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Sample records for anion transporter sat1

  1. Ability of sat-1 to transport sulfate, bicarbonate, or oxalate under physiological conditions.

    Science.gov (United States)

    Krick, Wolfgang; Schnedler, Nina; Burckhardt, Gerhard; Burckhardt, Birgitta C

    2009-07-01

    Tubular reabsorption of sulfate is achieved by the sodium-dependent sulfate transporter, NaSi-1, located at the apical membrane, and the sulfate-anion exchanger, sat-1, located at the basolateral membrane. To delineate the physiological role of rat sat-1, [(35)S]sulfate and [(14)C]oxalate uptake into sat-1-expressing oocytes was determined under various experimental conditions. Influx of [(35)S]sulfate was inhibited by bicarbonate, thiosulfate, sulfite, and oxalate, but not by sulfamate and sulfide, in a competitive manner with K(i) values of 2.7 +/- 1.3 mM, 101.7 +/- 9.7 microM, 53.8 +/- 10.9 microM, and 63.5 +/- 38.7 microM, respectively. Vice versa, [(14)C]oxalate uptake was inhibited by sulfate with a K(i) of 85.9 +/- 9.5 microM. The competitive type of inhibition indicates that these compounds are most likely substrates of sat-1. Physiological plasma bicarbonate concentrations (25 mM) reduced sulfate and oxalate uptake by more than 75%. Simultaneous application of sulfate, bicarbonate, and oxalate abolished sulfate as well as oxalate uptake. These data and electrophysiological studies using a two-electrode voltage-clamp device provide evidence that sat-1 preferentially works as an electroneutral sulfate-bicarbonate or oxalate-bicarbonate exchanger. In kidney proximal tubule cells, sat-1 likely completes sulfate reabsorption from the ultrafiltrate across the basolateral membrane in exchange for bicarbonate. In hepatocytes, oxalate extrusion is most probably mediated either by an exchange for sulfate or bicarbonate. PMID:19369292

  2. Transportcharakteristika des Sulfat Anionen Transporter 1, sat-1, und seine Regulation durch Vorstufen des Oxalats

    OpenAIRE

    Schnedler, Nina

    2010-01-01

    Nierensteine sind eine weit verbreitete Erkrankung und bestehen meistens aus Calciumoxalat. Über den Oxalattransport im Körper ist bis heute wenig bekannt. Im Rahmen dieser Arbeit wurde der Sulfat Anionen Transporter 1 (sat-1) untersucht, der neben Sulfat auch Oxalat und Bicarbonat transportiert und in Leber, Nieren und wahrscheinlich auch im Darm lokalisiert ist. Die Transportcharakteristika des sat-1 wurden in sat-1-exprimierenden Oozyten, die Regulation des sat-1 in HepG2-Zellen, die de...

  3. SAT1, a glutamine transporter, is preferentially expressed in GABAergic neurons

    Directory of Open Access Journals (Sweden)

    Tom Tallak Solbu

    2010-02-01

    Full Text Available Subsets of GABAergic neurons are able to maintain high frequency discharge patterns, which requires efficient replenishment of the releasable pool of GABA. Although glutamine is considered a preferred precursor of GABA, the identity of transporters involved in glutamine uptake by GABAergic neurons remains elusive. Molecular analyses revealed that SAT1 (Slc38a1 features system A characteristics with a preferential affinity for glutamine, and that SAT1 mRNA expression is associated with GABAergic neurons. By generating specific antibodies against SAT1 we show that this glutamine carrier is particularly enriched in GABAergic neurons. Cellular SAT1 distribution resembles that of GAD67, an essential GABA synthesis enzyme, suggesting that SAT1 can be involved in translocating glutamine into GABAergic neurons to facilitate inhibitory neurotransmitter generation.

  4. Anion Transport with Chalcogen Bonds.

    Science.gov (United States)

    Benz, Sebastian; Macchione, Mariano; Verolet, Quentin; Mareda, Jiri; Sakai, Naomi; Matile, Stefan

    2016-07-27

    In this report, we introduce synthetic anion transporters that operate with chalcogen bonds. Electron-deficient dithieno[3,2-b;2',3'-d]thiophenes (DTTs) are identified as ideal to bind anions in the focal point of the σ holes on the cofacial endocyclic sulfur atoms. Anion binding in solution and anion transport across lipid bilayers are found to increase with the depth of the σ holes of the DTT anionophores. These results introduce DTTs and related architectures as a privileged motif to engineer chalcogen bonds into functional systems, complementary in scope to classics such as 2,2'-bipyrroles or 2,2'-bipyridines that operate with hydrogen bonds and lone pairs, respectively. PMID:27433964

  5. Towards predictable transmembrane transport: QSAR analysis of anion binding and anion transport

    OpenAIRE

    Gale, Philip A.; Busschaert, Nathalie; Bradberry, Samuel J.; Wenzel, Marco; Haynes, Cally; Hiscock, Jennifer R.; Kirby, Isabelle; Karagiannidis, Louise E.; Moore, Stephen J.; Wells, Neil; Herniman, Julie; Langley, John; Horton, Peter; Mark E. Light; Marques, Igor

    2013-01-01

    The transport of anions across biological membranes by small molecules is a growing research field due to the potential therapeutic benefits of these compounds. However, little is known about the exact mechanism by which these drug-like molecules work and which molecular features make a good transporter. An extended series of 1-hexyl-3-phenylthioureas were synthesized, fully characterized (NMR, mass spectrometry, IR and single crystal diffraction) and their anion binding and anion transport p...

  6. Anion transport and GABA signaling

    Directory of Open Access Journals (Sweden)

    Christian Andreas Huebner

    2013-10-01

    Full Text Available Whereas activation of GABAA receptors by GABA usually results in a hyperpolarizing influx of chloride into the neuron, the reversed chloride driving force in the immature nervous system results in a depolarizing efflux of chloride. This GABAergic depolarization is deemed to be important for the maturation of the neuronal network. The concept of a developmental GABA switch has mainly been derived from in vitro experiments and reliable in vivo evidence is still missing. As GABAA receptors are permeable for both chloride and bicarbonate, the net effect of GABA also critically depends on the distribution of bicarbonate. Whereas chloride can either mediate depolarizing or hyperpolarizing currents, bicarbonate invariably mediates a depolarizing current under physiological conditions. Intracellular bicarbonate is quickly replenished by cytosolic carbonic anhydrases. Intracellular bicarbonate levels also depend on different bicarbonate transporters expressed by neurons. The expression of these proteins is not only developmentally regulated but also differs between cell types and even subcellular regions. In this review we will summarize current knowledge about the role of some of these transporters for brain development and brain function.

  7. Intestinal transporters for endogenic and pharmaceutical organic anions

    DEFF Research Database (Denmark)

    Grandvuinet, Anne Sophie; Vestergaard, Henrik Tang; Rapin, Nicolas; Steffansen, Bente

    2012-01-01

    This review provides an overview of intestinal human transporters for organic anions and stresses the need for standardization of the various in-vitro methods presently employed in drug-drug interaction (DDI) investigations.......This review provides an overview of intestinal human transporters for organic anions and stresses the need for standardization of the various in-vitro methods presently employed in drug-drug interaction (DDI) investigations....

  8. Two independent anion transport systems in rabbit mandibular salivary glands

    DEFF Research Database (Denmark)

    Novak, I; Young, J A

    1986-01-01

    Cholinergically stimulated Cl and HCO3 transport in perfused rabbit mandibular glands has been studied with extracellular anion substitution and administration of transport inhibitors. In glands perfused with HCO3-free solutions, replacement of Cl with other anions supported secretion in the...... stimulated secretion by about 30%, but when infused in addition to furosemide (0.1 mmol/l), it inhibited by about 20%. Amiloride (1.0 mmol/l) caused no inhibition. The results suggest that there are at least three distinct carriers in the rabbit mandibular gland. One is a furosemide-sensitive Na-coupled Cl...

  9. Organic anion transporter 3- and organic anion transporting polypeptides 1B1- and 1B3-mediated transport of catalposide

    Directory of Open Access Journals (Sweden)

    Jeong HU

    2015-01-01

    Full Text Available Hyeon-Uk Jeong,1 Mihwa Kwon,2 Yongnam Lee,3 Ji Seok Yoo,3 Dae Hee Shin,3 Im-Sook Song,2 Hye Suk Lee1 1College of Pharmacy, The Catholic University of Korea, Bucheon 420-743, Korea; 2College of Pharmacy and Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu 702-701, Korea; 3Central R&D Institute, Yungjin Pharm Co., Ltd., Suwon 443-270, Korea Abstract: We investigated the in vitro transport characteristics of catalposide in HEK293 cells overexpressing organic anion transporter 1 (OAT1, OAT3, organic anion transporting polypeptide 1B1 (OATP1B1, OATP1B3, organic cation transporter 1 (OCT1, OCT2, P-glycoprotein (P-gp, and breast cancer resistance protein (BCRP. The transport mechanism of catalposide was investigated in HEK293 and LLC-PK1 cells overexpressing the relevant transporters. The uptake of catalposide was 319-, 13.6-, and 9.3-fold greater in HEK293 cells overexpressing OAT3, OATP1B1, and OATP1B3 transporters, respectively, than in HEK293 control cells. The increased uptake of catalposide via the OAT3, OATP1B1, and OATP1B3 transporters was decreased to basal levels in the presence of representative inhibitors such as probenecid, furosemide, and cimetidine (for OAT3 and cyclosporin A, gemfibrozil, and rifampin (for OATP1B1 and OATP1B3. The concentration-dependent OAT3-mediated uptake of catalposide revealed the following kinetic parameters: Michaelis constant (Km =41.5 µM, maximum uptake rate (Vmax =46.2 pmol/minute, and intrinsic clearance (CLint =1.11 µL/minute. OATP1B1- and OATP1B3-mediated catalposide uptake also showed concentration dependency, with low CLint values of 0.035 and 0.034 µL/minute, respectively. However, the OCT1, OCT2, OAT1, P-gp, and BCRP transporters were apparently not involved in the uptake of catalposide into cells. In addition, catalposide inhibited the transport activities of OAT3, OATP1B1, and OATP1B3 with half-maximal inhibitory concentration values of 83, 200, and 235 µ

  10. Epithelial Anion Transport as Modulator of Chemokine Signaling

    Science.gov (United States)

    Schnúr, Andrea; Hegyi, Péter; Rousseau, Simon; Lukacs, Gergely L.; Veit, Guido

    2016-01-01

    The pivotal role of epithelial cells is to secrete and absorb ions and water in order to allow the formation of a luminal fluid compartment that is fundamental for the epithelial function as a barrier against environmental factors. Importantly, epithelial cells also take part in the innate immune system. As a first line of defense they detect pathogens and react by secreting and responding to chemokines and cytokines, thus aggravating immune responses or resolving inflammatory states. Loss of epithelial anion transport is well documented in a variety of diseases including cystic fibrosis, chronic obstructive pulmonary disease, asthma, pancreatitis, and cholestatic liver disease. Here we review the effect of aberrant anion secretion with focus on the release of inflammatory mediators by epithelial cells and discuss putative mechanisms linking these transport defects to the augmented epithelial release of chemokines and cytokines. These mechanisms may contribute to the excessive and persistent inflammation in many respiratory and gastrointestinal diseases. PMID:27382190

  11. Hydroxide Solvation and Transport in Anion Exchange Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chen [Univ. of Chicago, IL (United States); Wuhan Univ. (China); Tse, Ying-Lung Steve [Univ. of Chicago, IL (United States); Lindberg, Gerrick E. [Northern Arizona Univ., Flagstaff, AZ (United States); Knight, Chris [Argonne National Lab. (ANL), Argonne, IL (United States); Voth, Gregory A. [Univ. of Chicago, IL (United States)

    2016-01-27

    Understanding hydroxide solvation and transport in anion exchange membranes (AEMs) can provide important insight into the design principles of these new membranes. To accurately model hydroxide solvation and transport, we developed a new multiscale reactive molecular dynamics model for hydroxide in aqueous solution, which was then subsequently modified for an AEM material. With this model, we investigated the hydroxide solvation structure and transport mechanism in the membrane. We found that a relatively even separation of the rigid side chains produces a continuous overlapping region for hydroxide transport that is made up of the first hydration shell of the tethered cationic groups. Our results show that hydroxide has a significant preference for this overlapping region, transporting through it and between the AEM side chains with substantial contributions from both vehicular (standard diffusion) and Grotthuss (proton hopping) mechanisms. Comparison of the AEM with common proton exchange membranes (PEMs) showed that the excess charge is less delocalized in the AEM than the PEMs, which is correlated with a higher free energy barrier for proton transfer reactions. The vehicular mechanism also contributes considerably more than the Grotthuss mechanism for hydroxide transport in the AEM, while our previous studies of PEM systems showed a larger contribution from the Grotthuss mechanism than the vehicular mechanism for proton transport. The activation energy barrier for hydroxide diffusion in the AEM is greater than that for proton diffusion in PEMs, implying a more significant enhancement of ion transport in the AEM at elevated temperatures.

  12. Efficient, non-toxic anion transport by synthetic carriers in cells and epithelia

    Science.gov (United States)

    Li, Hongyu; Valkenier, Hennie; Judd, Luke W.; Brotherhood, Peter R.; Hussain, Sabir; Cooper, James A.; Jurček, Ondřej; Sparkes, Hazel A.; Sheppard, David N.; Davis, Anthony P.

    2016-01-01

    Transmembrane anion transporters (anionophores) have potential for new modes of biological activity, including therapeutic applications. In particular they might replace the activity of defective anion channels in conditions such as cystic fibrosis. However, data on the biological effects of anionophores are scarce, and it remains uncertain whether such molecules are fundamentally toxic. Here, we report a biological study of an extensive series of powerful anion carriers. Fifteen anionophores were assayed in single cells by monitoring anion transport in real time through fluorescence emission from halide-sensitive yellow fluorescent protein. A bis-(p-nitrophenyl)ureidodecalin shows especially promising activity, including deliverability, potency and persistence. Electrophysiological tests show strong effects in epithelia, close to those of natural anion channels. Toxicity assays yield negative results in three cell lines, suggesting that promotion of anion transport may not be deleterious to cells. We therefore conclude that synthetic anion carriers are realistic candidates for further investigation as treatments for cystic fibrosis.

  13. Expression and function of renal and hepatic organic anion transporters in extrahepatic cholestasis

    Institute of Scientific and Technical Information of China (English)

    Anabel Brandoni; María Herminia Hazelhoff; Romina Paula Bulacio; Adriana Mónica Torres

    2012-01-01

    Obstructive jaundice occurs in patients suffering from cholelithiasis and from neoplasms affecting the pancreas and the common bile duct.The absorption,distribution and elimination of drugs are impaired during this pathology.Prolonged cholestasis may alter both liver and kidney function.Lactam antibiotics,diuretics,non-steroidal anti-inflammatory drugs,several antiviral drugs as well as endogenous compounds are classified as organic anions.The hepatic and renal organic anion transport pathways play a key role in the pharmacokinetics of these compounds.It has been demonstrated that acute extrahepatic cholestasis is associated with increased renal elimination of organic anions.The present work describes the molecular mechanisms involved in the regulation of the expression and function of the renal and hepatic organic anion transporters in extrahepatic cholestasis,such as multidrug resistanceassociated protein 2,organic anion transporting polypeptide 1,organic anion transporter 3,bilitranslocase,bromosulfophthalein/bilirubin binding protein,organic anion transporter 1 and sodium dependent bile salt transporter.The modulation in the expression of renal organic anion transporters constitutes a compensatory mechanism to overcome the hepatic dysfunction in the elimination of organic anions.

  14. Synthetic ion transporters can induce apoptosis by facilitating chloride anion transport into cells

    Science.gov (United States)

    Ko, Sung-Kyun; Kim, Sung Kuk; Share, Andrew; Lynch, Vincent M.; Park, Jinhong; Namkung, Wan; van Rossom, Wim; Busschaert, Nathalie; Gale, Philip A.; Sessler, Jonathan L.; Shin, Injae

    2014-10-01

    Anion transporters based on small molecules have received attention as therapeutic agents because of their potential to disrupt cellular ion homeostasis. However, a direct correlation between a change in cellular chloride anion concentration and cytotoxicity has not been established for synthetic ion carriers. Here we show that two pyridine diamide-strapped calix[4]pyrroles induce coupled chloride anion and sodium cation transport in both liposomal models and cells, and promote cell death by increasing intracellular chloride and sodium ion concentrations. Removing either ion from the extracellular media or blocking natural sodium channels with amiloride prevents this effect. Cell experiments show that the ion transporters induce the sodium chloride influx, which leads to an increased concentration of reactive oxygen species, release of cytochrome c from the mitochondria and apoptosis via caspase activation. However, they do not activate the caspase-independent apoptotic pathway associated with the apoptosis-inducing factor. Ion transporters, therefore, represent an attractive approach for regulating cellular processes that are normally controlled tightly by homeostasis.

  15. Synthetic ion transporters that work with anion-π interactions, halogen bonds, and anion-macrodipole interactions.

    Science.gov (United States)

    Vargas Jentzsch, Andreas; Hennig, Andreas; Mareda, Jiri; Matile, Stefan

    2013-12-17

    The transport of ions and molecules across lipid bilayer membranes connects cells and cellular compartments with their environment. This biological process is central to a host of functions including signal transduction in neurons and the olfactory and gustatory sensing systems, the translocation of biosynthetic intermediates and products, and the uptake of nutrients, drugs, and probes. Biological transport systems are highly regulated and selectively respond to a broad range of physical and chemical stimulation. A large percentage of today's drugs and many antimicrobial or antifungal agents take advantage of these systems. Other biological transport systems are highly toxic, such as the anthrax toxin or melittin from bee venom. For more than three decades, organic and supramolecular chemists have been interested in developing new transport systems. Over time, curiosity about the basic design has evolved toward developing of responsive systems with applications in materials sciences and medicine. Our early contributions to this field focused on the introduction of new structural motifs with emphasis on rigid-rod scaffolds, artificial β-barrels, or π-stacks. Using these scaffolds, we have constructed selective systems that respond to voltage, pH, ligands, inhibitors, or light (multifunctional photosystems). We have described sensing applications that cover the three primary principles of sensor development: immunosensors that use aptamers, biosensors (an "artificial" tongue), and differential sensors (an "artificial" nose). In this Account, we focus on our recent interest in applying synthetic transport systems as analytical tools to identify the functional relevance of less common noncovalent interactions, anion-π interactions, halogen bonds, and anion-macrodipole interactions. Anion-π interactions, the poorly explored counterpart of cation-π interactions, occur in aromatic systems with a positive quadrupole moment, such as TNT or hexafluorobenzene. To observe

  16. Aza-Bambusurils En Route to Anion Transporters.

    Science.gov (United States)

    Singh, Mandeep; Solel, Ephrath; Keinan, Ehud; Reany, Ofer

    2016-06-20

    Previous calculations of anion binding with various bambusuril analogs predicted that the replacement of oxygen by nitrogen atoms to produce semiaza-bambus[6]urils would award these new cavitands with multiple anion binding properties. This study validates the hypothesis by efficient synthesis, crystallography, thermogravimetric analysis and calorimetry. These unique host molecules are easily accessible from the corresponding semithio-bambusurils in a one-pot reaction, which converts a single anion receptor into a potential anion channel. Solid-state structures exhibit simultaneous accommodation of three anions, linearly positioned within the cavity along the main symmetry axis. The ability to hold anions at a short distance of about 4 Å is reminiscent of natural chloride channels in E. coli, which exhibit similar distances between their adjacent anion binding sites. The calculated transition-state energy for double-anion movement through the channel suggests that although these host-guest complexes are thermodynamically stable they enjoy high kinetic flexibility to render them efficient anion channels. PMID:27225332

  17. TU Sat 1: A Novel Communications and Scientific Satellite

    OpenAIRE

    Holmes, W. C.; Bryson, Josh; Gerig, Brent; Oehrig, Jacob; Rodriguez, Jonathan; Schea, Jeremy; Schutt, Noel; Voss, David; Voss, Jonathan; Whittington, David; Bennett, Adam; Fennig, Chris; Brandle, Stefan; Dailey, Jeff; Voss, H.D.

    2002-01-01

    TU Sat 1 is a multipurpose nanosatellite scheduled for launch on the first CubeSat mission, a 650 km polar orbit. TU Sat 1 provides a low-cost store and forward email communication system for individuals in 3rd world nations. The satellite includes a 115 Kbps primary transceiver and a 1.2 Kbps secondary Ham transceiver. The primary data link uses a 900 MHz COTS data transceiver with a lightweight patch antenna. The satellite 386 CPU on a board processes scientific data, emails and attachments...

  18. Organic anion transporter (Slc22a) family members as mediators of toxicity

    International Nuclear Information System (INIS)

    Exposure of the body to toxic organic anions is unavoidable and occurs from both intentional and unintentional sources. Many hormones, neurotransmitters, and waste products of cellular metabolism, or their metabolites, are organic anions. The same is true for a wide variety of medications, herbicides, pesticides, plant and animal toxins, and industrial chemicals and solvents. Rapid and efficient elimination of these substances is often the body's best defense for limiting both systemic exposure and the duration of their pharmacological or toxicological effects. For organic anions, active transepithelial transport across the renal proximal tubule followed by elimination via the urine is a major pathway in this detoxification process. Accordingly, a large number of organic anion transport proteins belonging to several different gene families have been identified and found to be expressed in the proximal nephron. The function of these transporters, in combination with the high volume of renal blood flow, predisposes the kidney to increased toxic susceptibility. Understanding how the kidney mediates the transport of organic anions is integral to achieving desired therapeutic outcomes in response to drug interactions and chemical exposures, to understanding the progression of some disease states, and to predicting the influence of genetic variation upon these processes. This review will focus on the organic anion transporter (OAT) family and discuss the known members, their mechanisms of action, subcellular localization, and current evidence implicating their function as a determinant of the toxicity of certain endogenous and xenobiotic agents

  19. NigComSat-1R Entered into Orbit Precisely

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    China launched the NigComSat-1R communications satellite with a Long March 3B/E from the Xichang Satellite Launch Center (XSLC) at 00:41 on December 20.Twenty six minutes after the lift-off,the satellite separated with the rocket and entered precisely into a geostationary transfer orbit with a perigee of 203km,an apogee of 42007km and an inelination of 24.8 degrees.

  20. Function of the anion transporter AtCLC-d in the trans-Golgi network

    OpenAIRE

    von der Fecht-Bartenbach, Jennifer; Bogner, Martin; Krebs, Melanie; Stierhof, York-Dieter; Schumacher, Karin; Ludewig, Uwe

    2007-01-01

    Anion transporting proteins of the CLC type are involved in anion homeostasis in a variety of organisms. CLCs from Arabidopsis have been shown to participate in nitrate accumulation and storage. In this study, the physiological role of the functional chloride transporter AtCLC-d from Arabidopsis was investigated. AtCLC-d is weakly expressed in various tissues, including the root. When transiently expressed as a GFP fusion in protoplasts, it co-localized with the VHA-a1 subunit of the proton-t...

  1. Interaction of sirolimus and everolimus with hepatic and intestinal organic anion-transporting polypeptide transporters.

    Science.gov (United States)

    Picard, Nicolas; Levoir, Laure; Lamoureux, Fabien; Yee, Sook Wah; Giacomini, Kathleen M; Marquet, Pierre

    2011-09-01

    The goal of this study was to assess the interaction of the mTOR inhibitors (ImTORs) sirolimus and everolimus with the human organic anion-transporting polypeptides (OATPs) expressed in hepatocytes and enterocytes by conducting uptake experiments using (i) transfected HEK293T cells, (ii) the hepatocyte-like HepaRG cell line and (iii) the enterocyte-like Caco-2 cell line. Sirolimus and everolimus inhibited in a dose-dependent manner the uptake of [³H]-estrone sulphate by OATP1A2 and OATP1B1 and that of mycophenolic acid 7-O-glucuronide (MPAG) by OATP1B3. ImTOR apparent 50% inhibitory concentrations (IC₅₀) for OATPs were 11.9 µM (OATP1A2), 9.8 µM (OATP1B1) and 1.3 µM (OATP1B3) for sirolimus and 4.2 µM (OATP1A2), 4.1 µM (OATP1B1) and 4.3 µM (OATP1B3) for everolimus. No transport of sirolimus or everolimus by OATP1A2, OATP1B1 or OATP1B3 was observed in HEK-transfected cells and the OAT/OATP/MRP chemical inhibitor probenecid did not significantly decrease the uptake of sirolimus and everolimus in HepaRG and Caco-2 cells, but tended to increase their intracellular accumulation presumably through efflux inhibition. In conclusion, our data suggest that the major OATP transporters expressed in the liver and the intestine do not contribute to the pharmacokinetics of sirolimus and everolimus. However, ImTORs are inhibitors of these transporters. PMID:21524191

  2. Molecular architecture and the structural basis for anion interaction in prestin and SLC26 transporters

    Science.gov (United States)

    Gorbunov, Dmitry; Sturlese, Mattia; Nies, Florian; Kluge, Murielle; Bellanda, Massimo; Battistutta, Roberto; Oliver, Dominik

    2014-04-01

    Prestin (SLC26A5) is a member of the SLC26/SulP anion transporter family. Its unique quasi-piezoelectric mechanical activity generates fast cellular motility of cochlear outer hair cells, a key process underlying active amplification in the mammalian ear. Despite its established physiological role, it is essentially unknown how prestin can generate mechanical force, since structural information on SLC26/SulP proteins is lacking. Here we derive a structural model of prestin and related transporters by combining homology modelling, MD simulations and cysteine accessibility scanning. Prestin’s transmembrane core region is organized in a 7+7 inverted repeat architecture. The model suggests a central cavity as the substrate-binding site located midway of the anion permeation pathway, which is supported by experimental solute accessibility and mutational analysis. Anion binding to this site also controls the electromotile activity of prestin. The combined structural and functional data provide a framework for understanding electromotility and anion transport by SLC26 transporters.

  3. Polyspecific drug and steroid clearance by an organic anion transporter of mammalian liver

    NARCIS (Netherlands)

    Bossuyt, [No Value; Muller, M; Hagenbuch, B; Meier, PJ

    1996-01-01

    An organic anion-transporting polypeptide that mediates sodium-independent uptake of negatively charged sulfobromophthalein and bile salts has recently been cloned from rat liver (Jacquemin et al., 1994). In this study we have extended the substrate specificity studies to neutral and positively char

  4. Extracellular Cl(-) regulates human SO4 (2-)/anion exchanger SLC26A1 by altering pH sensitivity of anion transport.

    Science.gov (United States)

    Wu, Meng; Heneghan, John F; Vandorpe, David H; Escobar, Laura I; Wu, Bai-Lin; Alper, Seth L

    2016-08-01

    Genetic deficiency of the SLC26A1 anion exchanger in mice is known to be associated with hyposulfatemia and hyperoxaluria with nephrolithiasis, but many aspects of human SLC26A1 function remain to be explored. We report here the functional characterization of human SLC26A1, a 4,4'-diisothiocyanato-2,2'-stilbenedisulfonic acid (DIDS)-sensitive, electroneutral sodium-independent anion exchanger transporting sulfate, oxalate, bicarbonate, thiosulfate, and (with divergent properties) chloride. Human SLC26A1-mediated anion exchange differs from that of its rodent orthologs in its stimulation by alkaline pHo and inhibition by acidic pHo but not pHi and in its failure to transport glyoxylate. SLC26A1-mediated transport of sulfate and oxalate is highly dependent on allosteric activation by extracellular chloride or non-substrate anions. Extracellular chloride stimulates apparent V max of human SLC26A1-mediated sulfate uptake by conferring a 2-log decrease in sensitivity to inhibition by extracellular protons, without changing transporter affinity for extracellular sulfate. In contrast to SLC26A1-mediated sulfate transport, SLC26A1-associated chloride transport is activated by acid pHo, shows reduced sensitivity to DIDS, and exhibits cation dependence of its DIDS-insensitive component. Human SLC26A1 resembles SLC26 paralogs in its inhibition by phorbol ester activation of protein kinase C (PKC), which differs in its undiminished polypeptide abundance at or near the oocyte surface. Mutation of SLC26A1 residues corresponding to candidate anion binding site-associated residues in avian SLC26A5/prestin altered anion transport in patterns resembling those of prestin. However, rare SLC26A1 polymorphic variants from a patient with renal Fanconi Syndrome and from a patient with nephrolithiasis/calcinosis exhibited no loss-of-function phenotypes consistent with disease pathogenesis. PMID:27125215

  5. Roles of organic anion transporters in the progression of chronic renal failure.

    Science.gov (United States)

    Enomoto, Atsushi; Niwa, Toshimitsu

    2007-10-01

    Renal proximal and distal tubules carry out specialized directional transport of various solutes. The family of organic anion transporters (OATs), which belongs to the major facilitator superfamily (SLC22A), are expressed in the renal epithelial cells to regulate the excretion and the reabsorption of endogenous and exogenous organic anions that include various kinds of drugs and their metabolites. In recent years, it is revealed that indoxyl sulfate, one of uremic toxins, is a novel physiological substrate for OAT family, and its accumulation within the renal tubules via OATs induces renal dysfunction. The OATs are also expressed in the blood-brain barrier, muscle cells, and bone osteoblasts, which hint at various pathogenic roles of OAT-mediated transport of uremic toxins. In this review, we introduce and discuss the function of OATs in the context of their roles in the progression of chronic renal disease. PMID:17976081

  6. Influence of glucose and urea on 125I transport across an anion exchange paper membrane

    International Nuclear Information System (INIS)

    In order to study the influence of glucose and urea on the 125I transport across an anion exchange paper membrane, the transmembrane potential, the fluxes, and the concentrations of 125I, glucose and urea within the membrane were measured in the Na125I concentration-cell system containing glucose or urea. Glucose and urea increased the membrane/solution distribution of the iodide ion, but scarcely affected the diffusion process of iodide ion within the membrane

  7. Molecular evidence for an involvement of organic anion transporters (OATs) in aristolochic acid nephropathy.

    OpenAIRE

    Bakhiya, Nadiya; Arlt, Volker M.; Bahn, Andrew; Burckhardt, Gerhard; Phillips, David H.; Glatt, Hansruedi

    2009-01-01

    Aristolochic acid (AA), present in Aristolochia species, is the major causative agent in the development of severe renal failure and urothelial cancers in patients with AA nephropathy. It may also be a cause of Balkan endemic nephropathy. Epithelial cells of the proximal tubule are the primary cellular target of AA. To study whether organic anion transporters (OATs) expressed in proximal tubule cells are involved in uptake of AA, we used human epithelial kidney (HEK293) cells stably expressin...

  8. Adsorption-transport modeling of anions through PVD membrane in the presence of the screen phenomenon

    Science.gov (United States)

    Madaeni, S. S.; Salehi, E.

    2009-01-01

    A mathematical model for transport and adsorption of chloride and sulphate ions through PVD membrane is presented at two pressures; 8 and 15 bar and 40 °C. The PVD membrane is negatively charged. Saturated brine containing NaCl with the concentration higher than 97% was challenged with the membrane as the feed. Other available ions in the solution were Fe 2+, Ca 2+, Mg 2+ and SO 42-. The screen effect of the cations on the membrane surface charge facilitates the passage of the anions through the membrane without any noticeable electrostatic repulsion. Hermia blocking laws combined with experimental results indicate that the internal pore closure of the membrane by anions and cake deposition on the membrane surface by cations are the separation mechanisms. The transmission of anions through the membrane may be predicted with a simple transport equation (convection and diffusion) combined with an adsorption isotherm. Both Langmuir and Freundlich adsorption isotherms were employed due to the simplicity and validity in liquid systems. The isotherm's parameters were determined at 10 bar during the unsteady state filtration. Under this condition, the permeate flux and concentration varied sharply due to adsorption. Finally, the model was compared with the experimental rejection data. An acceptable agreement around 95% at 8 bar and 92% at 15 bar was observed between theoretical model and experimental data.

  9. Anion exchange pathways for Cl- transport in rabbit renal microvillus membranes

    International Nuclear Information System (INIS)

    The authors evaluated the mechanisms of chloride transport in microvillus membrane vesicles isolated from the rabbit renal cortex. The presence of Cl-formate exchange was confirmed. Outward gradients of oxaloacetate, HCO3, acetate, lactate, succinate, sulfate, and p-aminohippurate (PAH) stimulated the rate of Cl uptake minimally or not at all. However, an outward gradient of oxalate stimulated Cl uptake by 70%, and an outward Cl gradient induced uphill oxalate uptake, indicting Cl-oxalate exchange. Moreover, an outward formate gradient induced uphill oxalate uptake, indicating formate-oxalate exchange. Studies of inhibitor and substrate specificity indicated the probably operation of at least two separate anion exchangers in mediating Cl transport. The Cl-formate exchanger accepted Cl and formate as substrates, had little or no affinity for oxalate, was sensitive to inhibition by furosemide, and was less sensitive to inhibition by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). The Cl (formate)-oxalate exchanger also accepted Cl and formate as substrates but had high affinity for oxalate, was highly sensitive to inhibition by DIDS, and was less sensitive to inhibition by furosemide. The Cl-formate exchanger was electroneutral, whereas the Cl (formate)-oxalate exchanger was electrogenic. They conclude that at least separate anion exchangers mediating Cl transport are present on the luminal membrane of the rabbit proximal tubule cell. These exchangers may play important roles in mediating transtubular Cl and oxalate transport in this nephron segment

  10. Organic anion transporter OAT1 is involved in renal handling of citrulline.

    Science.gov (United States)

    Nakakariya, Masanori; Shima, Yoichiro; Shirasaka, Yoshiyuki; Mitsuoka, Keisuke; Nakanishi, Takeo; Tamai, Ikumi

    2009-07-01

    Because citrulline plasma concentration is elevated in kidney failure, citrulline could be a biomarker of renal insufficiency, although the mechanism regulating its disposition in the kidney has not been clarified. In rat kidney slices, citrulline uptake was apparently Na(+) dependent, saturable with K(m) 556 microM, and significantly inhibited by anionic (PAH) and cationic (TEA) compounds, but not by probenecid at 1 mM. Preincubation of kidney slices with glutarate increased citrulline uptake, while such an increase was not observed after preincubation of the slices in Na(+)-free buffer. This result suggested that a sodium-dependent dicarboxylate cotransporter is involved in citrulline uptake by rat kidney slices. In studies using transporter-overexpressing cells, human organic anion transporter 1 (OAT1) and rat Oat1 exhibited citrulline transport activity with K(m) values of 238 and 373 microM, respectively, while other OATs and organic cation transporters (OCTs) did not transport citrulline. Based on the relative activity factor method, the contribution of rat Oat1 to the overall uptake of citrulline in rat kidney slices was approximately 70%. Moreover, the interaction among citrulline, PAH, and probenecid uptakes via rat Oat1 suggested that there are multiple functional sites on Oat1 and that the citrulline site may be distinct from the PAH and probenecid site. Thus OAT1/Oat1 appears to be one of the major contributors to renal basolateral uptake of citrulline, and impaired activities of these transporters may contribute substantially to the increase in plasma citrulline in renal failure. Accordingly, citrulline may be useful for diagnosis of kidney function as is creatinine. PMID:19403644

  11. Electrically silent anion transport through bilayer lipid membrane induced by tributyltin and triethyllead.

    Science.gov (United States)

    Antonenko YuN

    1990-02-01

    The method of the measurement of the nonelectrogenic fluxes of hydrogen (or hydroxyl) ions (JH) based on the local proton gradients formation in the unstirred layers near a bilayer lipid membrane (BLM) is applied for recording the nonelectrogenic anion/OH- exchange on BLM induced by tributyltin (TBT) and a novel carrier (Hager, A., Moser, I., & Berthold, W. 1987. Z. Naturforsch., 42C:1116-1120), triethyllead (TEL). This method has been used previously for measuring the cation fluxes through BLM. TBT and TEL are shown to be equally efficient in the induction of Cl-/OH- exchange. JH induced by TBT is constant at 4 less than pH less than 7. JH decreases at pH less than 4 and pH greater than 7. Both ionophores have a transport sequence: I- greater than Br- greater than Cl- greater than F-. The quantitative measurements reveal that TEL better discriminates these four anions than TBT. It is concluded that this method may prove helpful in a search and study of anion/OH(-)-exchangers isolated from natural membranes. PMID:2319590

  12. Effects of cation and anion solvation on ion transport in functionalized perfluoropolyethers electrolytes

    Science.gov (United States)

    Timachova, Ksenia; Chintapalli, Mahati; Olsen, Kevin; Desimone, Joseph; Balsara, Nitash

    Advances in polymer electrolytes for use in lithium batteries have been limited by the incorporation of selective lithium binding groups that provide necessary solvation for the lithium but ultimately restrict the mobility of the lithium ions relative to anions. Perfluoropolyether electrolytes (PFPE) are a new class of nonflammable liquid polymer electrolytes that have been functionalized with solvating groups for both lithium ions and fluorinated anions. PFPEs with different endgroups mixed with LiN(SO2CF3)2 salt have shown substantial differences in conductivity and allows us to investigate the effects of varying solvating environments on ion transport. To study the independent motion of cations and anions in these systems, the individual diffusion coefficients of the Li + and (SO2CF3)2 - ions were measured using pulsed-field gradient nuclear magnetic resonance (PFG-NMR). Comparing conductivity calculated using these diffusion coefficients with electrochemical measurements yields an estimation for the number of charge carrier in the system. The amount of salt dissociation, not the mobility of the salt, is the primary driver of differences in electrochemical conductivities between PFPEs with different solvating groups.

  13. Contribution of hepatic organic anion-transporting polypeptides to docetaxel uptake and clearance.

    Science.gov (United States)

    Lee, Hannah H; Leake, Brenda F; Teft, Wendy; Tirona, Rommel G; Kim, Richard B; Ho, Richard H

    2015-04-01

    The antimicrotubular agent docetaxel is a widely used chemotherapeutic drug for the treatment of multiple solid tumors and is predominantly dependent on hepatic disposition. In this study, we evaluated drug uptake transporters capable of transporting radiolabeled docetaxel. By screening an array of drug uptake transporters in HeLa cells using a recombinant vaccinia-based method, five organic anion-transporting polypeptides (OATP) capable of docetaxel uptake were identified: OATP1A2, OATP1B1, OATP1B3, OATP1C1, and Oatp1b2. Kinetic analysis of docetaxel transport revealed similar kinetic parameters among hepatic OATP1B/1b transporters. An assessment of polymorphisms (SNPs) in SLCO1B1 and SLCO1B3 revealed that a number of OATP1B1 and OATP1B3 variants were associated with impaired docetaxel transport. A Transwell-based vectorial transport assay using MDCKII stable cells showed that docetaxel was transported significantly into the apical compartment of double-transfected (MDCKII-OATP1B1/MDR1 and MDCKII-OATP1B3/MDR1) cells compared with single-transfected (MDCKII-OATP1B1 and MDCKII-OATP1B3) cells (P control (MDCKII-Co) cells (P 5.5-fold higher plasma concentrations (P < 0.01) and approximately 3-fold decreased liver-to-plasma ratio (P < 0.05) of docetaxel compared with wild-type (WT) mice. The plasma clearance of docetaxel in Slco1b2(-/-) mice was 83% lower than WT mice (P < 0.05). In conclusion, this study demonstrates the important roles of OATP1B transporters to the hepatic disposition and clearance of docetaxel, and supporting roles of these transporters for docetaxel pharmacokinetics. PMID:25695959

  14. Ammonium Bicarbonate Transport in Anion Exchange Membranes for Salinity Gradient Energy

    KAUST Repository

    Geise, Geoffrey M.

    2013-09-17

    Many salinity gradient energy technologies such as reverse electrodialysis (RED) rely on highly selective anion transport through polymeric anion exchange membranes. While there is considerable interest in using thermolytic solutions such as ammonium bicarbonate (AmB) in RED processes for closed-loop conversion of heat energy to electricity, little is known about membrane performance in this electrolyte. The resistances of two commercially available cation exchange membranes in AmB were lower than their resistances in NaCl. However, the resistances of commercially available anion exchange membranes (AEMs) were much larger in AmB than in NaCl, which would adversely affect energy recovery. The properties of a series of quaternary ammonium-functionalized poly(phenylene oxide) and Radel-based AEMs were therefore examined to understand the reasons for increased resistance in AmB to overcome this performance penalty due to the lower mobility of bicarbonate, 4.59 × 10-4 cm2/(V s), compared to chloride, 7.90 × 10-4 cm2/(V s) (the dilute aqueous solution mobility ratio of HCO3 - to Cl- is 0.58). Most membrane resistances were generally consistent with the dilute solution mobilities of the anions. For a few key samples, however, increased water uptake in AmB solution reduced the ionic resistance of the polymer compared to its resistance in NaCl solution. This increased water uptake was attributed to the greater hydration of the bicarbonate ion compared to the chloride ion. The increased resistance due to the use of bicarbonate as opposed to chloride ions in AEMs can therefore be mitigated by designing polymers that swell more in AmB compared to NaCl solutions, enabling more efficient energy recovery using AmB thermolytic solutions in RED. © 2013 American Chemical Society.

  15. Renal Organic Anion Transporters (SLC22 Family): Expression, Regulation, Roles in Toxicity, and Impact on Injury and Disease

    OpenAIRE

    Wang, Li; Sweet, Douglas H.

    2012-01-01

    Organic solute flux across the basolateral and apical membranes of renal proximal tubule cells is a key process for maintaining systemic homeostasis. It represents an important route for the elimination of metabolic waste products and xenobiotics, as well as for the reclamation of essential compounds. Members of the organic anion transporter (OAT, SLC22) family expressed in proximal tubules comprise one pathway mediating the active renal secretion and reabsorption of organic anions. Many drug...

  16. Organic anion transporting polypeptides in the hepatic uptake of PBDE congeners in mice

    International Nuclear Information System (INIS)

    BDE47, BDE99 and BDE153 are the predominant polybrominated diphenyl ether (PBDE) congeners detected in humans and can induce drug metabolizing enzymes in the liver. We have previously demonstrated that several human liver organic anion transporting polypeptides (humans: OATPs; rodents: Oatps) can transport PBDE congeners. Mice are commonly used to study the toxicity of chemicals like the PBDE congeners. However, the mechanism of the hepatic PBDE uptake in mice is not known. Therefore, the purpose of the current study was to test the hypothesis that BDE47, BDE99, and BDE153 are substrates of mouse hepatic Oatps (Oatp1a1, Oatp1a4, Oatp1b2, and Oatp2b1). We used Human Embryonic Kidney 293 (HEK293) cells transiently expressing individual Oatps and quantified the uptake of BDE47, BDE99, and BDE153. Oatp1a4, Oatp1b2, and Oatp2b1 transported all three PBDE congeners, whereas Oatp1a1 did transport none. Kinetic studies demonstrated that Oatp1a4 and Oatp1b2 transported BDE47 with the greatest affinity, followed by BDE99 and BDE153. In contrast, Oatp2b1 transported all three PBDE congeners with similar affinities. The importance of hepatic Oatps for the liver accumulation of BDE47 was confirmed using Oatp1a4-, and Oatp1b2-null mice. -- Highlights: ► PBDE congeners are substrates of OATPs expressed in human hepatocytes. ► Mice are commonly used to study the toxicity of chemicals like the PBDE congeners. ► Oatp1a4, Oatp1b2, and Oatp2b1 transported all three PBDE congeners in vitro. ► In vivo Oatp1a4 plays a minor and Oatp1b2 a major role in BDE47 liver accumulation.

  17. Flight Results from the GeneSat-1 Biological Microsatellite Mission

    OpenAIRE

    Kitts, Christopher; Ronzano, Karolyn; Rasay, Richard; Mas, Ignacio; Williams, Phelps; Mahacek, Paul; Minelli, Giovanni; Hines, John; Agasid, Elwood; Friedericks, Charlie; Piccini, Matthew; Parra, Macarena; Timucin, Linda; Beasley, C.; Henschke, Mike

    2007-01-01

    The mission of the GeneSat-1 technology demonstration spacecraft is to validate the use of research-quality instrumentation for in situ biological research and processing. To execute this mission, the GeneSat-1 satellite was launched on December 16, 2006 from Wallops Flight Facility as a secondary payload off of a Minotaur launch vehicle. During the first week of operation, the core biological growth test was successfully executed, and by the end of the first month of operation all primary sc...

  18. Rapid screening of antineoplastic candidates for the human organic anion transporter OATP1B3 substrates using fluorescent probes

    OpenAIRE

    Yamaguchi, Hiroaki; KOBAYASHI, Minako; Okada, Masahiro; Takeuchi, Toshiko; Unno, Michiaki; ABE, Takaaki; Goto, Junichi; Hishinuma, Takanori; Mano, Nariyasu

    2008-01-01

    A rapid screening system has been established to extract novel candidates that exhibit potent inhibition of the transport of fluorescent substrate by organic anion transporting polypeptide (OATP) 1B3. OATP1B3 is abundantly expressed in solid digestive organ cancers. Thus, the identification of new substrates leads to novel strategies for effective cancer chemotherapy with minimal adverse effects. We used an automated image acquisition and analysis system (IN Cell Analyzer 1000) to visualize ...

  19. Sulfuric Acid and Ammonia Generation by Bipolar Membranes Electrodialysis: Transport Rate Model for Ion and Water through Anion Exchange Membrane

    OpenAIRE

    Zhang, Xiaoyan; Lu, Wenhua; Ren, HongYan; Cong, Wei

    2008-01-01

    Regeneration of sulfuric acid and ammonia from ammonium sulfate by bipolar membrane electrodialysis (BMED) coupling with stripping ammonia by air-blowing was studied. The result showed that it was feasible to regenerate sulfuric acid and ammonia from ammonium sulfate solution using this method. Empirical models to describe the ion and water transport behaviors through anion exchange membrane for BMED system were successfully developed. The models were valid to evaluate water transport rate an...

  20. Fruit juice, organic anion transporting polypeptides, and drug interactions in psychiatry.

    Science.gov (United States)

    Andrade, Chittaranjan

    2014-11-01

    Organic anion transporting polypeptides (OATPs) are a group of membrane transport proteins that facilitate the influx of endogenous and exogenous substances across biological membranes. OATPs are found in enterocytes and hepatocytes and in brain, kidney, and other tissues. In enterocytes, OATPs facilitate the gastrointestinal absorption of certain orally administered drugs. Fruit juices such as grapefruit juice, orange juice, and apple juice contain substances that are OATP inhibitors. These fruit juices diminish the gastrointestinal absorption of certain antiallergen, antibiotic, antihypertensive, and β-blocker drugs. While there is no evidence, so far, that OATP inhibition affects the absorption of psychotropic medications, there is no room for complacency because the field is still nascent and because the necessary studies have not been conducted. Patients should therefore err on the side of caution, taking their medications at least 4 hours distant from fruit juice intake. Doing so is especially desirable with grapefruit juice, orange juice, and apple juice; with commercial fruit juices in which OATP-inhibiting substances are likely to be present in higher concentrations; with calcium-fortified fruit juices; and with medications such as atenolol and fexofenadine, the absorption of which is substantially diminished by concurrent fruit juice intake. PMID:25470100

  1. Understanding ion and solvent transport in anion exchange membranes under humidified conditions

    Science.gov (United States)

    Sarode, Himanshu

    Anion exchange membranes (AEM) have been studied for more than a decade for potential applications in low temperature fuel cells and other electrochemical devices. They offer the advantage of faster reaction kinetics under alkaline conditions and ability to perform without costly platinum catalyst. Inherently slow diffusion of hydroxide ions compared to protons is a primary reason for synthesizing and studying the ion transport properties in AEMs. The aim of this thesis is to understand ion transport in novel AEMs using Pulse Gradient stimulated Spin Echo Nuclear Magnetic Resonance technique (PGSE NMR), water uptake, ionic conductivity, Small Angle X-ray Scattering (SAXS) etc. All experiments were performed under humidified conditions (80--95% relative humidity) and fuel cell operating temperatures of 30--90°C. In this work, the NMR tube design was modified for humidifying the entire NMR tube evenly from our previous design. We have developed a new protocol for replacing caustic hydroxide with harmless fluoride or bicarbonate ions for 19F and 13 C NMR diffusion experiments. After performing these NMR experiments, we have obtained in-depth understanding of the morphology linked ion transport in AEMs. We have obtained the highest fluoride self-diffusion coefficient of > 1 x 10-5 cm2/sec ( 55°C) for ETFE-g-PVBTMA membrane which is a result of low tortuosity of 1 obtained for the membrane. This faster fluoride transport combined with low tortuosity of the membrane resulted in > 100mS/cm hydroxide conductivity for the membrane. Polycyclooctene (PCOE) based triblock copolymers are also studied for in-depth understanding of molecular weight, IEC, mechanical and transport properties. Effect of melting temperature of PCOE has favorable effect on increasing ion conductivity and lowering activation energy. Mechanical properties of these types of membranes were studied showing detrimental effect of water plasticization which results in unsuitable mechanical properties

  2. Organic anion and cation transport in vitro by dog choroid plexus: Effects of neuroleptics and tricyclic antidepressants

    International Nuclear Information System (INIS)

    Dog lateral choroid plexus accumulates the cation 14C-emepronium and the divalent anion 125I-iodipamide in vitro. At 10 μM, high potency neuroleptics with a substituted piperazine side chain and also haloperidol depress only the uptake of the cation and even stimulate the uptake of the anion. In contrast, at 1-10μM, the accumulation of both test substances is inhibited by neuroleptics and tricyclic antidepresssants with an aliphatic side chain. Such unspecific effects on seemingly unrelated transport systems at concentrations reached clinically in the CSF might explain some side actions of low potency neuroleptics and antidepressants. (author)

  3. SAT-1 -1415T/C polymorphism and susceptibility to schizophrenia.

    Science.gov (United States)

    Bermudo-Soriano, Carlos Riaza; Vaquero-Lorenzo, Concepcion; Diaz-Hernandez, Montserrat; Perez-Rodriguez, M Mercedes; Fernandez-Piqueras, Jose; Saiz-Ruiz, Jeronimo; Baca-Garcia, Enrique

    2009-03-17

    Patients suffering from psychosis show increased blood and fibroblast total polyamine levels. Spermidine/spermine N1-acetyltransferase (SSAT-1) and its coding gene (SAT-1) are the main factors regulating polyamine catabolism. The aim of the present study was to examine the association between the SAT-1 -1415T/C single nucleotide polymorphism (SNP) and schizophrenia. A case-control design was used in order to compare the genotypes for the SNP between schizophrenia patients (n=180, 83 females and 97 males), other non-psychotic psychiatric patients (n=413, 256 females and 157 males), and healthy controls (n=251, 101 females and 150 males). No significant differences in the distribution of the genotypes of the SAT-1 -1415T/C SNP were found groups among groups. We failed to demonstrate a significant association between the SAT-1 -1415T/C SNP and schizophrenia, but a mild association between allele C and psychopathology was found in the female group. PMID:19162121

  4. Evidence for functional interaction of plasma membrane electron transport, voltage-dependent anion channel and volume-regulated anion channel in frog aorta

    Indian Academy of Sciences (India)

    Rashmi P Rao; J Prakasa Rao

    2010-12-01

    Frog aortic tissue exhibits plasma membrane electron transport (PMET) owing to its ability to reduce ferricyanide even in the presence of mitochondrial poisons, such as cyanide and azide. Exposure to hypotonic solution (108 mOsmol/kg H2O) enhanced the reduction of ferricyanide in excised aortic tissue of frog. Increment in ferricyanide reductase activity was also brought about by the presence of homocysteine (100 M dissolved in isotonic frog Ringer solution), a redox active compound and a potent modulator of PMET. Two plasma-membrane-bound channels, the volume regulated anion channel (VRAC) and the voltage-dependent anion channel (VDAC), are involved in the response to hypotonic stress. The presence of VRAC and VDAC antagonists–tamoxifen, glibenclamide, fluoxetine and verapamil, and 4,4′-diisothiocyanatostilbene-2,2′-disulphonic acid (DIDS), respectively–inhibited this enhanced activity brought about by either hypotonic stress or homocysteine. The blockers do not affect the ferricyanide reductase activity under isotonic conditions. Taken together, these findings indicate a functional interaction of the three plasma membrane proteins, namely, ferricyanide reductase (PMET), VDAC and VRAC.

  5. Organic anion transporting polypeptide-1B1 haplotypes in Chinese patients

    Institute of Scientific and Technical Information of China (English)

    Lin-yong XU; Hong-hao ZHOU; Zhen-qiu SUN; Yi-jing HE; Wei ZHANG; Sheng Deng; Qing LI; Wei-xia ZHANG; Zhao-qian LIU; Dan WANG; Yuan-fei HUANG

    2007-01-01

    Aim: To detect 388G>A and 521T>C variant alleles in the organic anion transporting polypeptide- 1B 1 (OATP 1B 1, encoding gene SLCOIB1) gene. Methods:One hundred and eleven healthy volunteers were screened for OATPIB 1 alleles in our study. PCR-restriction fragment length polymorphism was used to identify the 388G>A polymorphism and a 1-step tetra-primer method was developed for the determination of 521T>C mutation. Results: The frequencies of the 388G>A and 521T>C variant alleles in the Chinese population were 73.4%and 14.0%,respectively. The frequencies of the SLCO1BI*lb and *15 haplotypes were 59.9% and 14.0%, respectively. Conclusion: The SLCO1B1*1b and SLCO1B1*15 variants are relatively common in the Chinese population. Their frequencies are similar to that in the Japanese, but significantly different from that in Caucasians and blacks.

  6. POTENT INHIBITORS OF HUMAN ORGANIC ANION TRANSPORTERS 1 AND 3 FROM CLINICAL DRUG LIBRARIES: DISCOVERY AND MOLECULAR CHARACTERIZATION

    OpenAIRE

    Duan, Peng; Li, Shanshan; Ai, Ni; Hu, Longqin; Welsh, William J.; You, Guofeng

    2012-01-01

    Transporter-mediated drug-drug interactions in the kidney dramatically influence the pharmacokinetics and other clinical effects of drugs. Human organic anion transporters 1 (hOAT1) and 3 (hOAT3) are the major transporters in the basolateral membrane of kidney proximal tubules, mediating the rate-limiting step in the elimination of a broad spectrum of drugs. In the present study, we screened two clinical drug libraries against hOAT1 and hOAT3. Of the 727 compounds screened, 92 compounds inhib...

  7. Arsenic retention and transport behavior in the presence of typical anionic and nonionic surfactants.

    Science.gov (United States)

    Liang, Chuan; Wang, Xianliang; Peng, Xianjia

    2016-01-01

    The massive production and wide use of surfactants have resulted in a large amount of surfactant residuals being discharged into the environment, which could have an impact on arsenic behavior. In the present study, the influence of the anionic surfactant sodium dodecyl benzene sulfonate (SDBS) and nonionic surfactant polyethylene glycol octylphenyl ether (Triton X-100) on arsenic behavior was investigated in batch and column tests. The presence of SDBS and Triton X-100 reduced arsenic retention onto ferrihydrite (FH), enhanced arsenic transport through FH coated sand (FH-sand) columns and promoted arsenic release from the FH surface. With coexisting surfactants in solution, the equilibrium adsorbed amount of arsenic on FH decreased by up to 29.7% and the adsorption rate decreased by up to 52.3%. Pre-coating with surfactants caused a decrease in the adsorbed amount and adsorption rate of arsenic by up to 15.1% and 58.3%, respectively. Because of the adsorption attenuation caused by surfactants, breakthrough of As(V) and As(III) with SDBS in columns packed with FH-sand was 23.8% and 14.3% faster than that in those without SDBS, respectively. In columns packed with SDBS-coated FH-sand, transport of arsenic was enhanced to a greater extent. Breakthrough of As(V) and As(III) was 52.4% and 43.8% faster and the cumulative retention amount was 44.5% and 57.3% less than that in pure FH-sand column systems, respectively. Mobilization of arsenic by surfactants increased with the increase of the initial adsorbed amount of arsenic. The cumulative release amount of As(V) and As(III) from the packed column reached 10.8% and 36.0%, respectively. PMID:26899663

  8. Organic anion transporting polypeptide 1a1 null mice are sensitive to cholestatic liver injury.

    Science.gov (United States)

    Zhang, Youcai; Csanaky, Iván L; Cheng, Xingguo; Lehman-McKeeman, Lois D; Klaassen, Curtis D

    2012-06-01

    Organic anion transporting polypeptide 1a1 (Oatp1a1) is predominantly expressed in livers of mice and is thought to transport bile acids (BAs) from blood into liver. Because Oatp1a1 expression is markedly decreased in mice after bile duct ligation (BDL). We hypothesized that Oatp1a1-null mice would be protected against liver injury during BDL-induced cholestasis due largely to reduced hepatic uptake of BAs. To evaluate this hypothesis, BDL surgeries were performed in both male wild-type (WT) and Oatp1a1-null mice. At 24 h after BDL, Oatp1a1-null mice showed higher serum alanine aminotransferase levels and more severe liver injury than WT mice, and all Oatp1a1-null mice died within 4 days after BDL, whereas all WT mice survived. At 24 h after BDL, surprisingly Oatp1a1-null mice had higher total BA concentrations in livers than WT mice, suggesting that loss of Oatp1a1 did not prevent BA accumulation in the liver. In addition, secondary BAs dramatically increased in serum of Oatp1a1-null BDL mice but not in WT BDL mice. Oatp1a1-null BDL mice had similar basolateral BA uptake (Na(+)-taurocholate cotransporting polypeptide and Oatp1b2) and BA-efflux (multidrug resistance-associated protein [Mrp]-3, Mrp4, and organic solute transporter α/β) transporters, as well as BA-synthetic enzyme (Cyp7a1) in livers as WT BDL mice. Hepatic expression of small heterodimer partner Cyp3a11, Cyp4a14, and Nqo1, which are target genes of farnesoid X receptor, pregnane X receptor, peroxisome proliferator-activated receptor alpha, and NF-E2-related factor 2, respectively, were increased in WT BDL mice but not in Oatp1a1-null BDL mice. These results demonstrate that loss of Oatp1a1 function exacerbates cholestatic liver injury in mice and suggest that Oatp1a1 plays a unique role in liver adaptive responses to obstructive cholestasis. PMID:22461449

  9. Probenecid-resistant J774 cell expression of enhanced organic anion transport by a mechanism distinct from multidrug resistance.

    Science.gov (United States)

    Cao, C; Steinberg, T H; Neu, H C; Cohen, D; Horwitz, S B; Hickman, S; Silverstein, S C

    1993-08-01

    Macrophages possess organic anion transporters that carry membrane-impermeant fluorescent dyes, such as lucifer yellow (LY) and carboxy-fluorescein, from the cytoplasm into endosomes and out of the cells. Probenecid, an organic anion transport inhibitor, blocks these processes. Prolonged incubation of J774 cells in medium containing 2.5 mM probenecid eventually kills most of these cells. To identify J774 variants that express increased organic anion transport activity, we selected probenecid-resistant (PBR) J774 cells by growing them in medium containing increasing concentrations of probenecid. When PBR and unselected J774 cells were loaded with LY by ATP4- permeabilization, the amount of LY accumulated by the PBR cells was about half that in the unselected cells. This difference was abolished by adding 10 mM probenecid to the medium in which the cells were loaded, suggesting that the diminished LY accumulation in PBR cells was due to enhanced LY secretion and that the PBR cells expressed increased organic anion transport activity. Direct comparison of LY efflux from J774 and PBR J774 cells showed a faster initial rate of secretion of LY from PBR J774 cells than from unselected J774 cells. To determine whether LY efflux is mediated by P-glycoprotein, we compared LY efflux in unselected J774 cells, PBR J774 cells, and multidrug-resistant J774 cells (J7.C1). LY efflux from J7.C1 cells was not sensitive to verapamil, which inhibits multidrug-resistance transporters, and reverses the multidrug-resistant phenotype of J7.C1 cells. The rates of LY efflux from unselected J774 and J7.C1 cells were virtually identical.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7909709

  10. Tumor-Specific Expression of Organic Anion-Transporting Polypeptides: Transporters as Novel Targets for Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Veronika Buxhofer-Ausch

    2013-01-01

    Full Text Available Members of the organic anion transporter family (OATP mediate the transmembrane uptake of clinical important drugs and hormones thereby affecting drug disposition and tissue penetration. Particularly OATP subfamily 1 is known to mediate the cellular uptake of anticancer drugs (e.g., methotrexate, derivatives of taxol and camptothecin, flavopiridol, and imatinib. Tissue-specific expression was shown for OATP1B1/OATP1B3 in liver, OATP4C1 in kidney, and OATP6A1 in testis, while other OATPs, for example, OATP4A1, are expressed in multiple cells and organs. Many different tumor entities show an altered expression of OATPs. OATP1B1/OATP1B3 are downregulated in liver tumors, but highly expressed in cancers in the gastrointestinal tract, breast, prostate, and lung. Similarly, testis-specific OATP6A1 is expressed in cancers in the lung, brain, and bladder. Due to their presence in various cancer tissues and their limited expression in normal tissues, OATP1B1, OATP1B3, and OATP6A1 could be a target for tumor immunotherapy. Otherwise, high levels of ubiquitous expressed OATP4A1 are found in colorectal cancers and their metastases. Therefore, this OATP might serve as biomarkers for these tumors. Expression of OATP is regulated by nuclear receptors, inflammatory cytokines, tissue factors, and also posttranslational modifications of the proteins. Through these processes, the distribution of the transporter in the tissue will be altered, and a shift from the plasma membrane to cytoplasmic compartments is possible. It will modify OATP uptake properties and, subsequently, change intracellular concentrations of drugs, hormones, and various other OATP substrates. Therefore, screening tumors for OATP expression before therapy should lead to an OATP-targeted therapy with higher efficacy and decreased side effects.

  11. Selenium-containing organic nanoparticles as silent precursors for ultra-sensitive thiol-responsive transmembrane anion transport

    Science.gov (United States)

    Lang, Chao; Zhang, Xin; Dong, Zeyuan; Luo, Quan; Qiao, Shanpeng; Huang, Zupeng; Fan, Xiaotong; Xu, Jiayun; Liu, Junqiu

    2016-01-01

    An anion transporter with a selenoxide group was able to form nanoparticles in water, whose activity was fully turned off due to the aggregation effect. The formed nanoparticles have a uniform size and can be readily dispersed in water at high concentrations. Turn-on of the nanoparticles by reducing molecules is proposed to be a combined process, including the reduction of selenoxide to selenide, disassembly of the nanoparticles and location of the transporter to the lipid membrane. Accordingly, a special acceleration phase can be observed in the turn-on kinetic curves. Since turn-on of the nanoparticles is quantitatively related to the amount of reductant, the nanoparticles can be activated in a step-by-step manner. Due to the sensibility of this system to thiols, cysteine can be detected at low nanomolar concentrations. This ultra-sensitive thiol-responsive transmembrane anion transport system is quite promising in biological applications.An anion transporter with a selenoxide group was able to form nanoparticles in water, whose activity was fully turned off due to the aggregation effect. The formed nanoparticles have a uniform size and can be readily dispersed in water at high concentrations. Turn-on of the nanoparticles by reducing molecules is proposed to be a combined process, including the reduction of selenoxide to selenide, disassembly of the nanoparticles and location of the transporter to the lipid membrane. Accordingly, a special acceleration phase can be observed in the turn-on kinetic curves. Since turn-on of the nanoparticles is quantitatively related to the amount of reductant, the nanoparticles can be activated in a step-by-step manner. Due to the sensibility of this system to thiols, cysteine can be detected at low nanomolar concentrations. This ultra-sensitive thiol-responsive transmembrane anion transport system is quite promising in biological applications. Electronic supplementary information (ESI) available: Synthetic procedure and

  12. Does lipophilicity affect the effectiveness of a transmembrane anion transporter? Insight from squaramido-functionalized bis(choloyl) conjugates.

    Science.gov (United States)

    Li, Zhi; Deng, Li-Qun; Chen, Jin-Xiang; Zhou, Chun-Qiong; Chen, Wen-Hua

    2015-12-28

    Six squaramido-functionalized bis(choloyl) conjugates were synthesized and fully characterized on the basis of NMR ((1)H and (13)C) and ESI MS (LR and HR) data. Their transmembrane anionophoric activity was investigated in detail by means of chloride ion selective electrode technique and pyranine assay. The data indicate that this set of compounds is capable of promoting the transmembrane transport of anions presumably via proton/anion symport and anion exchange processes, and that lipophilicity in terms of clog P from 3.90 to 8.32 affects the apparent ion transport rate in a concentration-dependent fashion. Detailed kinetic analysis on the data obtained from both the chloride efflux and pH discharge experiments reveals that there may exist an optimum clog P range for the intrinsic ion transport rate. However, lipophilicity exhibits little effect on the effectiveness of this set of compounds in terms of either k2/Kdiss or EC50 values. PMID:26488550

  13. Molecular evidence for an involvement of organic anion transporters (OATs) in aristolochic acid nephropathy

    International Nuclear Information System (INIS)

    Aristolochic acid (AA), present in Aristolochia species, is the major causative agent in the development of severe renal failure and urothelial cancers in patients with AA nephropathy. It may also be a cause of Balkan endemic nephropathy. Epithelial cells of the proximal tubule are the primary cellular target of AA. To study whether organic anion transporters (OATs) expressed in proximal tubule cells are involved in uptake of AA, we used human epithelial kidney (HEK293) cells stably expressing human (h) OAT1, OAT3 or OAT4. AA potently inhibited the uptake of characteristic substrates, p-aminohippurate for hOAT1 and estrone sulfate for hOAT3 and hOAT4. Aristolochic acid I (AAI), the more cytotoxic and genotoxic AA congener, exhibited high affinity for hOAT1 (Ki = 0.6 μM) as well as hOAT3 (Ki = 0.5 μM), and lower affinity for hOAT4 (Ki = 20.6 μM). Subsequently, AAI-DNA adduct formation (investigated by 32P-postlabelling) was used as a measure of AAI uptake. Significantly higher levels of adducts occurred in hOAT-expressing cells than in control cells: this effect was abolished in the presence of the OAT inhibitor probenecid. In Xenopus laevis oocytes hOAT-mediated efflux of p-aminohippurate was trans-stimulated by extracellular AA, providing further molecular evidence for AA translocation by hOATs. Our study indicates that OATs can mediate the uptake of AA into proximal tubule cells and thereby participate in kidney cell damage by this toxin.

  14. Molecular evidence for an involvement of organic anion transporters (OATs) in aristolochic acid nephropathy.

    Science.gov (United States)

    Bakhiya, Nadiya; Arlt, Volker M; Bahn, Andrew; Burckhardt, Gerhard; Phillips, David H; Glatt, Hansruedi

    2009-10-01

    Aristolochic acid (AA), present in Aristolochia species, is the major causative agent in the development of severe renal failure and urothelial cancers in patients with AA nephropathy. It may also be a cause of Balkan endemic nephropathy. Epithelial cells of the proximal tubule are the primary cellular target of AA. To study whether organic anion transporters (OATs) expressed in proximal tubule cells are involved in uptake of AA, we used human epithelial kidney (HEK293) cells stably expressing human (h) OAT1, OAT3 or OAT4. AA potently inhibited the uptake of characteristic substrates, p-aminohippurate for hOAT1 and estrone sulfate for hOAT3 and hOAT4. Aristolochic acid I (AAI), the more cytotoxic and genotoxic AA congener, exhibited high affinity for hOAT1 (K(i)=0.6 microM) as well as hOAT3 (K(i)=0.5 microM), and lower affinity for hOAT4 (K(i)=20.6 microM). Subsequently, AAI-DNA adduct formation (investigated by (32)P-postlabelling) was used as a measure of AAI uptake. Significantly higher levels of adducts occurred in hOAT-expressing cells than in control cells: this effect was abolished in the presence of the OAT inhibitor probenecid. In Xenopus laevis oocytes hOAT-mediated efflux of p-aminohippurate was trans-stimulated by extracellular AA, providing further molecular evidence for AA translocation by hOATs. Our study indicates that OATs can mediate the uptake of AA into proximal tubule cells and thereby participate in kidney cell damage by this toxin. PMID:19643159

  15. Clinical CYP3A inhibitor alternatives to ketoconazole, clarithromycin and itraconazole, are not transported into the liver by hepatic organic anion transporting polypeptides and organic cation transporter 1.

    Science.gov (United States)

    Higgins, J William; Ke, Alice B; Zamek-Gliszczynski, Maciej J

    2014-11-01

    Ketoconazole is no longer available for clinical determination of worst-case victim drug-drug interaction (DDI) potential for cytochrome P450 3A (CYP3A)-substrate drugs; clarithromycin and itraconazole are the proposed replacements. Ketoconazole DDIs are described by unbound systemic exposures due to absence of carrier-facilitated hepatic uptake, but this aspect of clarithromycin and itraconazole disposition has not been investigated. At present, transport of clarithromycin, itraconazole, and hydroxyitraconazole by hepatic organic anion transporting polypeptides (OATPs) and organic cation transporter 1 (OCT1) was examined in vitro and in vivo. As for ketoconazole, uptake of clarithromycin, itraconazole, and hydroxyitraconazole into OATP1B1, OATP1B3, OATP2B1, and OCT1 expressing human embryonic kidney 293 (HEK293) cells was not greater than in vector controls. Uptake into these HEK293 cells and human hepatocytes was not impaired by the prototypical OATP, OCT, and sodium/taurocholate cotransporting polypeptide inhibitors bromosulfophthalein, imipramine, and taurocholate, respectively. In contrast, uptake of the positive controls, atorvastatin for OATPs and metformin for OCT1, was significantly enhanced by relevant transporter expression, and uptake into both these HEK293 cells and human hepatocytes was significantly impaired by prototypical inhibitors. In Oatp1a/1b gene cluster knockout mice, which lack the major hepatic Oatps, and in Oct1/2 knockout mice, ketoconazole, clarithromycin, itraconazole, and hydroxyitraconazole oral exposure was not increased, and the liver-to-blood partition coefficient (Kp) was not decreased. By contrast relative to wild-type mice, in Oatp1a/1b- and Oct1/2-knockout mice, atorvastatin and metformin oral exposure was significantly increased, and liver Kp was significantly decreased. The present studies provide in vitro and in vivo evidence that, like ketoconazole, clarithromycin, itraconazole, and hydroxyitraconazole are not transported

  16. Intestinal transporters for endogenic and pharmaceutical organic anions: The challenges of deriving in-vitro kinetic parameters for the prediction of clinically relevant drug-drug interactions

    DEFF Research Database (Denmark)

    Grandvuinet, Anne Sophie; Vestergaard, Henrik Tang; Rapin, Nicolas;

    2012-01-01

    the apical sodium-dependent bile acid transporter (ASBT), the breast cancer resistance protein (BCRP), the monocarboxylate transporters (MCT) 1, MCT3-5, the multidrug resistance associated proteins (MRP) 1-6, the organic anion transporting polypetides (OATP) 2B1, 1A2, 3A1 and 4A1, and the organic...

  17. Interaction of environmental contaminants with zebrafish organic anion transporting polypeptide, Oatp1d1 (Slco1d1).

    Science.gov (United States)

    Popovic, Marta; Zaja, Roko; Fent, Karl; Smital, Tvrtko

    2014-10-01

    Polyspecific transporters from the organic anion transporting polypeptide (OATP/Oatp) superfamily mediate the uptake of a wide range of compounds. In zebrafish, Oatp1d1 transports conjugated steroid hormones and cortisol. It is predominantly expressed in the liver, brain and testes. In this study we have characterized the transport of xenobiotics by the zebrafish Oatp1d1 transporter. We developed a novel assay for assessing Oatp1d1 interactors using the fluorescent probe Lucifer yellow and transient transfection in HEK293 cells. Our data showed that numerous environmental contaminants interact with zebrafish Oatp1d1. Oatp1d1 mediated the transport of diclofenac with very high affinity, followed by high affinity towards perfluorooctanesulfonic acid (PFOS), nonylphenol, gemfibrozil and 17α-ethinylestradiol; moderate affinity towards carbaryl, diazinon and caffeine; and low affinity towards metolachlor. Importantly, many environmental chemicals acted as strong inhibitors of Oatp1d1. A strong inhibition of Oatp1d1 transport activity was found by perfluorooctanoic acid (PFOA), chlorpyrifos-methyl, estrone (E1) and 17β-estradiol (E2), followed by moderate to low inhibition by diethyl phthalate, bisphenol A, 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4 tetrahydronapthalene and clofibrate. In this study we identified Oatp1d1 as a first Solute Carrier (SLC) transporter involved in the transport of a wide range of xenobiotics in fish. Considering that Oatps in zebrafish have not been characterized before, our work on zebrafish Oatp1d1 offers important new insights on the understanding of uptake processes of environmental contaminants, and contributes to the better characterization of zebrafish as a model species. PMID:25088042

  18. Carbon dioxide transport in molten calcium carbonate occurs through an oxo-Grotthuss mechanism via a pyrocarbonate anion

    Science.gov (United States)

    Corradini, Dario; Coudert, François-Xavier; Vuilleumier, Rodolphe

    2016-05-01

    The reactivity, speciation and solvation structure of CO2 in carbonate melts are relevant for both the fate of carbon in deep geological formations and for its electroreduction to CO (to be used as fuel) when solvated in a molten carbonate electrolyte. In particular, the high solubility of CO2 in carbonate melts has been tentatively attributed to the formation of the pyrocarbonate anion, C2O52–. Here we study, by first-principles molecular dynamics simulations, the behaviour of CO2 in molten calcium carbonate. We find that pyrocarbonate forms spontaneously and the identity of the CO2 molecule is quickly lost through O2– exchange. The transport of CO2 in this molten carbonate thus occurs in a fashion similar to the Grotthuss mechanism in water, and is three times faster than molecular diffusion. This shows that Grotthuss-like transport is more general than previously thought.

  19. Interaction of environmental contaminants with zebrafish organic anion transporting polypeptide, Oatp1d1 (Slco1d1)

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, Marta; Zaja, Roko [Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10 000 Zagreb (Croatia); Fent, Karl [University of Applied Sciences Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Swiss Federal Institute of Technology (ETH Zürich), Department of Environmental System Sciences, Institute of Biogeochemistry and Pollution Dynamics, CH-8092 Zürich (Switzerland); Smital, Tvrtko, E-mail: smital@irb.hr [Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10 000 Zagreb (Croatia)

    2014-10-01

    Polyspecific transporters from the organic anion transporting polypeptide (OATP/Oatp) superfamily mediate the uptake of a wide range of compounds. In zebrafish, Oatp1d1 transports conjugated steroid hormones and cortisol. It is predominantly expressed in the liver, brain and testes. In this study we have characterized the transport of xenobiotics by the zebrafish Oatp1d1 transporter. We developed a novel assay for assessing Oatp1d1 interactors using the fluorescent probe Lucifer yellow and transient transfection in HEK293 cells. Our data showed that numerous environmental contaminants interact with zebrafish Oatp1d1. Oatp1d1 mediated the transport of diclofenac with very high affinity, followed by high affinity towards perfluorooctanesulfonic acid (PFOS), nonylphenol, gemfibrozil and 17α-ethinylestradiol; moderate affinity towards carbaryl, diazinon and caffeine; and low affinity towards metolachlor. Importantly, many environmental chemicals acted as strong inhibitors of Oatp1d1. A strong inhibition of Oatp1d1 transport activity was found by perfluorooctanoic acid (PFOA), chlorpyrifos-methyl, estrone (E1) and 17β-estradiol (E2), followed by moderate to low inhibition by diethyl phthalate, bisphenol A, 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4 tetrahydronapthalene and clofibrate. In this study we identified Oatp1d1 as a first Solute Carrier (SLC) transporter involved in the transport of a wide range of xenobiotics in fish. Considering that Oatps in zebrafish have not been characterized before, our work on zebrafish Oatp1d1 offers important new insights on the understanding of uptake processes of environmental contaminants, and contributes to the better characterization of zebrafish as a model species. - Highlights: • We optimized a novel assay for determination of Oatp1d1 interactors • Oatp1d1 is the first SLC characterized fish xenobiotic transporter • PFOS, nonylphenol, diclofenac, EE2, caffeine are high affinity Oatp1d1substrates • PFOA, chlorpyrifos

  20. Interaction of environmental contaminants with zebrafish organic anion transporting polypeptide, Oatp1d1 (Slco1d1)

    International Nuclear Information System (INIS)

    Polyspecific transporters from the organic anion transporting polypeptide (OATP/Oatp) superfamily mediate the uptake of a wide range of compounds. In zebrafish, Oatp1d1 transports conjugated steroid hormones and cortisol. It is predominantly expressed in the liver, brain and testes. In this study we have characterized the transport of xenobiotics by the zebrafish Oatp1d1 transporter. We developed a novel assay for assessing Oatp1d1 interactors using the fluorescent probe Lucifer yellow and transient transfection in HEK293 cells. Our data showed that numerous environmental contaminants interact with zebrafish Oatp1d1. Oatp1d1 mediated the transport of diclofenac with very high affinity, followed by high affinity towards perfluorooctanesulfonic acid (PFOS), nonylphenol, gemfibrozil and 17α-ethinylestradiol; moderate affinity towards carbaryl, diazinon and caffeine; and low affinity towards metolachlor. Importantly, many environmental chemicals acted as strong inhibitors of Oatp1d1. A strong inhibition of Oatp1d1 transport activity was found by perfluorooctanoic acid (PFOA), chlorpyrifos-methyl, estrone (E1) and 17β-estradiol (E2), followed by moderate to low inhibition by diethyl phthalate, bisphenol A, 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4 tetrahydronapthalene and clofibrate. In this study we identified Oatp1d1 as a first Solute Carrier (SLC) transporter involved in the transport of a wide range of xenobiotics in fish. Considering that Oatps in zebrafish have not been characterized before, our work on zebrafish Oatp1d1 offers important new insights on the understanding of uptake processes of environmental contaminants, and contributes to the better characterization of zebrafish as a model species. - Highlights: • We optimized a novel assay for determination of Oatp1d1 interactors • Oatp1d1 is the first SLC characterized fish xenobiotic transporter • PFOS, nonylphenol, diclofenac, EE2, caffeine are high affinity Oatp1d1substrates • PFOA, chlorpyrifos

  1. Meta-analysis of expression of hepatic organic anion-transporting polypeptide (OATP) transporters in cellular systems relative to human liver tissue.

    Science.gov (United States)

    Badée, Justine; Achour, Brahim; Rostami-Hodjegan, Amin; Galetin, Aleksandra

    2015-04-01

    Organic anion-transporting polypeptide (OATP)1B1, OATP1B3, and OATP2B1 transporters play an important role in hepatic drug disposition. Recently, an increasing number of studies have reported proteomic expression data for OATP transporters. However, systematic analysis and understanding of the actual differences in OATP expression between liver tissue and commonly used cellular systems is lacking. In the current study, meta-analysis was performed to assess the protein expression of OATP transporters reported in hepatocytes relative to liver tissue and to identify any potential correlations in transporter expression levels in the same individual. OATP1B1 was identified as the most abundant uptake transporter at 5.9 ± 8.3, 5.8 ± 3.3, and 4.2 ± 1.7 fmol/μg protein in liver tissue, sandwich-cultured human hepatocytes (SCHH), and cryopreserved suspended hepatocytes, respectively. The rank order in average expression in liver tissue and cellular systems was OATP1B1 > OATP1B3 ≈ OATP2B1. Abundance levels of the OATP transporters investigated were not significantly different between liver and cellular systems, with the exception of OATP2B1 expression in SCHH relative to liver tissue. Analysis of OATP1B1, OATP1B3, and OATP2B1 liver expression data in the same individuals (n = 86) identified weak (OATP1B1-OATP2B1) to moderately (OATP1B3-OATP2B1) significant correlations. A significant weak correlation was noted between OATP1B1 abundance and age of human donors, whereas expression of the OATPs investigated was independent of sex. Implications of the current analysis on the in vitro-in vivo extrapolation of transporter-mediated drug disposition using physiologically based pharmacokinetic models are discussed. PMID:25564656

  2. Transport of strontium cation through a hollow fiber supported dichlorobenzene membrane using 18-C-6 crown ether. Nitrate and anion of dinonylnaphtalen sulfonic acid

    International Nuclear Information System (INIS)

    The transport of strontium cation through a hollow fiber supported dichlorobenzene membrane using 18-C-6 crown ether, nitrate and anion of dinonylnaphtalen sulfonic acid has been studied. A permeation device-single hollow fiber module with on-line radiometric detection of strontium using 85Sr tracer was used, (author). 5 refs., 7 figs., 1 tab

  3. Zinc Potentiates an Uncoupled Anion Conductance Associated with the Dopamine Transporter

    DEFF Research Database (Denmark)

    Meinild, Anne-Kristine; Sitte, Harald H; Gether, Ulrik

    2004-01-01

    Binding of Zn(2+) to an endogenous binding site in the dopamine transporter (DAT) leads to inhibition of dopamine (DA) uptake and enhancement of carrier-mediated substrate efflux. To elucidate the molecular mechanism for this dual effect, we expressed the DAT and selected mutants in Xenopus laevis...

  4. Interactions between organic anions on multiple transporters in Caco-2 cells

    DEFF Research Database (Denmark)

    Grandvuinet, Anne Sophie; Steffansen, Bente

    2011-01-01

    Caco-2 cell line may be used as an overall model to predict interactions on multiple membrane transporters in the intestine. Taurocholic acid (TCA) and estrone-3-sulfate (E1S) were used as model substrates. Possible inhibitors studied were TCA, E1S, taurolithocholic acid, fluvastatin, and glipizide...

  5. Key structural features for substrate binding to organic anion transporter 1 (Oat1; slc22a6) identified by global untargeted metabolomics of Oat1null plasma

    OpenAIRE

    William R. Wikoff; Nagle, Megha A.; Kouznetsova, Valentina L.; Tsigelny, Igor F.; Nigam, Sanjay K.

    2011-01-01

    Untargeted metabolomics on the plasma and urine from wild-type and organic anion transporter-1 (Oat1/Slc22a6) knockout mice identified a number of physiologically important metabolites, including several not previously linked to Oat1-mediated transport. Several, such as indoxyl sulfate, derive from Phase II metabolism of enteric gut precursors and accumulate in chronic kidney disease (CKD). Other compounds included vitamins (pantothenic acid, 4-pyridoxic acid), urate, and metabolites in the t...

  6. Untargeted metabolomics identifies enterobiome metabolites and putative uremic toxins as substrates of organic anion transporter 1 (Oat1).

    Science.gov (United States)

    Wikoff, William R; Nagle, Megha A; Kouznetsova, Valentina L; Tsigelny, Igor F; Nigam, Sanjay K

    2011-06-01

    Untargeted metabolomics on the plasma and urine from wild-type and organic anion transporter-1 (Oat1/Slc22a6) knockout mice identified a number of physiologically important metabolites, including several not previously linked to Oat1-mediated transport. Several, such as indoxyl sulfate, derive from Phase II metabolism of enteric gut precursors and accumulate in chronic kidney disease (CKD). Other compounds included vitamins (pantothenic acid, 4-pyridoxic acid), urate, and metabolites in the tryptophan and nucleoside pathways. Three metabolites, indoxyl sulfate, kynurenine, and xanthurenic acid, were elevated in the plasma and interacted strongly and directly with Oat1 in vitro with IC50 of 18, 12, and 50 μM, respectively. A pharmacophore model based on several identified Oat1 substrates was used to screen the NCI database and candidate compounds interacting with Oat1 were validated in an in vitro assay. Together, the data suggest a complex, previously unidentified remote communication between the gut microbiome, Phase II metabolism in the liver, and elimination via Oats of the kidney, as well as indicating the importance of Oat1 in the handling of endogenous toxins associated with renal failure and uremia. The possibility that some of the compounds identified may be part of a larger remote sensing and signaling pathway is also discussed. PMID:21476605

  7. Involvement of organic anion-transporting polypeptides in the hepatic uptake of dioscin in rats and humans.

    Science.gov (United States)

    Zhang, Aijie; Wang, Changyuan; Liu, Qi; Meng, Qiang; Peng, Jinyong; Sun, Huijun; Ma, Xiaochi; Huo, Xiaokui; Liu, Kexin

    2013-05-01

    The objective of this study was to clarify the mechanism underlying hepatic uptake of dioscin (diosgenyl 2,4-di-O-a-L-rhamnopyranosyl-p-D-glucopyranoside), an herbal ingredient with antihepatitis activity, in rats and humans. The liver uptake index (LUI) in vivo, perfused rat liver in situ, rat liver slices, isolated rat hepatocytes, and human organic anion-transporting polypeptide (OATP)-transfected cells in vitro were used to evaluate hepatic uptake of dioscin. Values of 11.9% ± 1.6% and 15.0% ± 0.9% of dose for uptake of dioscin were observed by LUI in vivo and perfused rat livers in situ, respectively. The time course of dioscin uptake by rat liver slices was temperature-dependent. Uptake of dioscin by rat liver slices and isolated rat hepatocytes was inhibited significantly by Oatp modulators, such as ibuprofen (Oatp1a1 inhibitor), digoxin (Oatp1a4 substrate), and glycyrrhizic acid (Oatp1b2 inhibitor), but not by TEA or p-aminohippurate. Uptake of dioscin in rat hepatocytes and OATP1B3-human embryonic kidney (HEK) 293 cells indicated a saturable process with a Km of 3.75 ± 0.51 μM and 2.08 ± 0.27 μM, respectively. (-)-Epigallocatechin gallate, cyclosporin A, rifampicin, and telmisartan inhibited transport of dioscin in OATP1B3-HEK293 cells. However, transcellular transport of dioscin in OATP1B1- or OATP1B1/multidrug resistance-associated protein 2-Madin-Darby canine kidney strain II cells was not observed. These results indicate that hepatic uptake of dioscin is involved in OATP1B3 in humans, and multiple Oatps might participate in this process in rats. PMID:23396419

  8. Evolutionary analysis of foot-and-mouth disease virus serotype SAT 1 isolates from east africa suggests two independent introductions from southern africa

    DEFF Research Database (Denmark)

    Sangula, Abraham K.; Belsham, Graham; Muwanika, Vincent B.;

    2010-01-01

    Background: In East Africa, foot-and-mouth disease virus serotype SAT 1 is responsible for occasional severe outbreaks in livestock and is known to be maintained within the buffalo populations. Little is known about the evolutionary forces underlying its epidemiology in the region. To enhance our...... appreciation of the epidemiological status of serotype SAT 1 virus in the region, we inferred its evolutionary and phylogeographic history by means of genealogy-based coalescent methods using 53 VP1 coding sequences covering a sampling period from 1948-2007. Results: The VP1 coding sequence of 11 serotype SAT...... 1 FMD viruses from East Africa has been determined and compared with known sequences derived from other SAT 1 viruses from sub-Saharan Africa. Purifying (negative) selection and low substitution rates characterized the SAT 1 virus isolates in East Africa. Two virus groups with probable independent...

  9. Atorvastatin improves renal organic anion transporter 3 and renal function in gentamicin-induced nephrotoxicity in rats.

    Science.gov (United States)

    Jaikumkao, Krit; Pongchaidecha, Anchalee; Chattipakorn, Nipon; Chatsudthipong, Varanuj; Promsan, Sasivimon; Arjinajarn, Phatchawan; Lungkaphin, Anusorn

    2016-06-01

    What is the central question of this study? This study was designed to determine the renoprotective effects of atorvastatin treatment in an experimental model of gentamicin-induced nephrotoxicity through modulating the Nrf2 pathway by decreasing the oxidative stress. What is the main finding and its importance? Atorvastatin exerts a nephroprotective effect by attenuating oxidative stress, protecting renal function and renal organic anion transporter 3 function from the effects of gentamicin. Atorvastatin might protect the tissues via its antioxidant property and by modulating the antioxidant enzymes through the Nrf2 signalling pathway, which may be the underlying mechanisms of these protective effects. Recent evidence demonstrates that statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, exert not only lipid-lowering effects but also antioxidant, anti-inflammatory and anti-apoptotic effects. Nephrotoxicity, a serious side-effect of gentamicin, is related to an increase in reactive oxygen species in the kidney. This study was designed to determine the renoprotective effects of atorvastatin treatment in an experimental model of gentamicin-induced nephrotoxicity. Male Sprague-Dawley rats were used. Nephrotocixity was induced by i.p. injection of gentamicin, 100 mg kg(-1)  day(-1) , for 15 days. Atorvastatin, 10 mg kg(-1)  day(-1) , was administered by gavage 30 min before gentamicin injection (pretreatment) for 15 days or only on days 10-15 (post-treatment). Renal function and renal organic anion transporter 3 (Oat3) function and expression were examined. Gentamicin-treated rats demonstrated impaired renal function by attenuation of creatinine clearance and increased oxidative stress. Gentamicin treatment also decreased renal Oat3 function and expression as shown by decreased [(3) H]estrone sulfate uptake into renal cortical slices and decreased expression. The protein expressions of protein kinase C, Nrf2, NAD(P)H:quinone oxidoreductase 1

  10. Studies on transport of anionic plutonium complex from nitric acid medium across ALIQUAT 336/N-dodecane liquid membrane

    International Nuclear Information System (INIS)

    Aliquat 336 is quaternary ammonium salt and its large organic cation is associated with chloride ion. It forms complexes with anions with wider range of acidity/pH and it works as anion exchanger. In the PUREX process, plutonium product solution is chemically conditioned to all plutonium into fourth valence state by addition of suitable amount of 13 M HNO3. The extraction of anionic complex of plutonium by Aliquat 336 is affected by anion exchange mechanism. This extraction mechanism is in resemblance with the ion exchange method used for purification and concentration of plutonium in the PUREX process

  11. Bezafibrate-mizoribine interaction: Involvement of organic anion transporters OAT1 and OAT3 in rats.

    Science.gov (United States)

    Feng, Yuan; Wang, Changyuan; Liu, Qi; Meng, Qiang; Huo, Xiaokui; Liu, Zhihao; Sun, Pengyuan; Yang, Xiaobo; Sun, Huijun; Qin, Jianhua; Liu, Kexin

    2016-01-01

    A patient with rheumatoid arthritis developed rhabdomyolysis while undergoing treatment with mizoribine concomitantly with bezafibrate. The symptoms rapidly disappeared and laboratory test results normalized when she discontinued the two drugs. The purpose of the present study was to elucidate the transporter-mediated molecular pharmacokinetic mechanisms of drug-drug interactions between bezafibrate and mizoribine. Comparing bezafibrate-mizoribine group with bezafibrate group, the Tmax and Cmax of bezafibrate were essentially unchanged in rats. The AUC of bezafibrate was significantly increased and t1/2β was prolonged markedly with an obviously reduction in plasma clearance and cumulative urinary excretion. The changes were similar to oral studies following intravenous co-administration. In rat kidney slices, the uptake of bezafibrate was markedly inhibited by p-aminohippurate, benzylpenicillin and probenecid but not by tetraethyl ammonium. Mizoribine not only decreased the uptake of bezafibrate, but also inhibited the uptake of p-aminohippurate and benzylpenicillin. The uptakes of bezafibrate and mizoribine were significantly higher compared to vector-HEK293 cells. The uptakes of bezafibrate and mizoribine in highest concentration were increased 1.63 and 1.46 folds in hOAT1-transfected cells, 1.43 and 1.24 folds in hOAT3-transfected cells, respectively. The Km values of bezafibrate uptake by hOAT1/3hOAT1-/hOAT3-HEK293 K293 cells were increased 1.68 fold in hOAT1-HEK293 cell and 2.12 fold in hOAT3-HEK293 cell in the presence of mizoribine with no change of Vmax. It indicated that mizoribine could inhibit the uptake of bezafibrate by hOAT1/3-HEK293 cells in a competitive way. In conclusion, OAT1 and OAT3 are the target transporters of drug-drug interactions between bezafibrate and mizoribine in pharmacokinetic aspects. PMID:26474691

  12. Novel insights into xenobiotic transport by organic anion transporting polypeptides (OATPs) and OATP-expression profiling in ovarian carcinoma and other solid tumors

    International Nuclear Information System (INIS)

    Eleven members of the organic anion transporting polypeptides (OATP) family have been identified in humans. They are responsible for the Na+ independent cellular uptake of a broad range of substances. The aim of this thesis was to investigate the possible role of OATPs present in various cancer entities including breast, bone, liver and ovary. In the first study, carrier-mediated uptake of paclitaxel was studied in X. laevis oocytes expressing all known human OATPs and in ovarian cancer cell lines. OATP1B1 could be identified as an uptake transporter for paclitaxel showing a Km value of 0.6 μM indicating high affinity to this taxane. Subsequently, the expression status of OATPs and several ABC transporters was assessed in malignant specimens from 191 ovarian cancer patients. OATP3A1 was significantly correlated with the FIGO stage of tumors. Moreover, OATP6A1, ABCB2 and ABCC3 were identified as highly significant predictor for the disease free survival of ovarian cancer patients. In additional studies we showed distinct OATP expression patterns in cancer tissues compared to normal tissue or benign tumors. In general, higher OATP levels were detected in normal tissues compared to malignant ones in breast cancer as well as bone cancer. In liver cancer, we observed upregulation of OATP2A1 and 5A1 in primary and secondary hepatic tumors but OATP4A1 was only upregulated in secondary hepatic tumors. The distinct expression pattern for individual OATPs in tumor cells suggest their specific functions which may involve transport of molecules important for cellular signaling as well as of drugs used in therapy. (author)

  13. The roles of anion and solvent transport during the redox switching process at a poly(butyl viologen) film studied by an EQCM

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Chih-Yu.; Liao, Chun-Hao [Department of Chemical Engineering, National Taiwan University, Taipei 10617 (China); Ho, Kuo-Chuan [Department of Chemical Engineering, National Taiwan University, Taipei 10617 (China); Institute of Polymer Science and Engineering, National Taiwan University, Taipei 10617 (China)

    2008-02-15

    In this study, three electrolytes (KCl, LiCl, and KNO{sub 3}, each at 0.5 M in aqueous solution) were chosen to study the ion and solvent effect on the redox performance of poly(butyl viologen) (PBV) thin-films between its di-cation and radical-cation state, which is referred as its first redox couple. Before considering the role of ionic transport on the redox process, the exchange between ferrocyanide and anion should be completed. Since the deposition solution of PBV contains potassium ferrocyanide, the residual ferrocyanides inside the films would be exchanged by smaller anions from the bulk solution during the redox reaction of PBV. From cyclic voltammetry (CV) and electrochemical quartz crystal microbalance (EQCM) results, the exchange was almost complete around 50 cycles when scanning the potential within its first redox range. After completion of the exchange process, the transfer would reach a steady state. At 50 cycles, the EQCM results suggested that the transport involves anions and water only for both being extracted upon reduction and being inserted upon oxidation. Therefore, we could obtain the molar fluxes of Cl{sup -}, NO{sub 3}{sup -}, and water. Besides, the average numbers of accompanying water were calculated to be about 24.8 per Cl{sup -} and 14.2 per NO{sub 3}{sup -} upon redox switching process. The instantaneous water to anion molar ratios at any potential were also obtained for Cl{sup -} and NO{sub 3}{sup -}. (author)

  14. Variability in hepatic expression of organic anion transporter 7/SLC22A9, a novel pravastatin uptake transporter: impact of genetic and regulatory factors.

    Science.gov (United States)

    Emami Riedmaier, A; Burk, O; van Eijck, B A C; Schaeffeler, E; Klein, K; Fehr, S; Biskup, S; Müller, S; Winter, S; Zanger, U M; Schwab, M; Nies, A T

    2016-08-01

    Human organic anion transporter 7 (OAT7, SLC22A9) is a hepatic transport protein poorly characterized so far. We therefore sought to identify novel OAT7 substrates and factors contributing to variable hepatic OAT7 expression. Using OAT7-expressing cells, pravastatin was identified as a substrate. Hepatic SLC22A9/OAT7 mRNA and protein expression varied 28-fold and 15-fold, respectively, in 126 Caucasian liver samples. Twenty-four variants in SLC22A9 were genotyped, including three rare missense variants (rs377211288, rs61742518, rs146027075), which occurred only heterozygously. No variant significantly affected hepatic SLC22A9/OAT7 expression. The three missense variants, however, showed functional consequences when expressed in vitro. Hepatic nuclear factor 4-alpha (HNF4α) emerged as a major transcriptional regulator of SLC22A9 by a series of in silico and in vitro analyses. In conclusion, pravastatin is the first identified OAT7 drug substrate. Substantial inter-individual variability in hepatic OAT7 expression, majorly driven by HNF4α, may contribute to pravastatin drug disposition and might affect response.The Pharmacogenomics Journal advance online publication, 4 August 2015; doi:10.1038/tpj.2015.55. PMID:26239079

  15. Complementarity of ResourceSat-1 AWiFS and Landsat TM/ETM+ sensors

    Science.gov (United States)

    Goward, S.N.; Chander, G.; Pagnutti, M.; Marx, A.; Ryan, R.; Thomas, N.; Tetrault, R.

    2012-01-01

    Considerable interest has been given to forming an international collaboration to develop a virtual moderate spatial resolution land observation constellation through aggregation of data sets from comparable national observatories such as the US Landsat, the Indian ResourceSat and related systems. This study explores the complementarity of India's ResourceSat-1 Advanced Wide Field Sensor (AWiFS) with the Landsat 5 Thematic Mapper (TM) and Landsat 7 Enhanced Thematic Mapper Plus (ETM+). The analysis focuses on the comparative radiometry, geometry, and spectral properties of the two sensors. Two applied assessments of these data are also explored to examine the strengths and limitations of these alternate sources of moderate resolution land imagery with specific application domains. There are significant technical differences in these imaging systems including spectral band response, pixel dimensions, swath width, and radiometric resolution which produce differences in observation data sets. None of these differences was found to strongly limit comparable analyses in agricultural and forestry applications. Overall, we found that the AWiFS and Landsat TM/ETM+ imagery are comparable and in some ways complementary, particularly with respect to temporal repeat frequency. We have found that there are limits to our understanding of the AWiFS performance, for example, multi-camera design and stability of radiometric calibration over time, that leave some uncertainty that has been better addressed for Landsat through the Image Assessment System and related cross-sensor calibration studies. Such work still needs to be undertaken for AWiFS and similar observatories that may play roles in the Global Earth Observation System of Systems Land Surface Imaging Constellation.

  16. Cysteinyl Leukotriene Receptor 1/2 Antagonists Nonselectively Modulate Organic Anion Transport by Multidrug Resistance Proteins (MRP1-4).

    Science.gov (United States)

    Csandl, Mark A; Conseil, Gwenaëlle; Cole, Susan P C

    2016-06-01

    Active efflux of both drugs and organic anion metabolites is mediated by the multidrug resistance proteins (MRPs). MRP1 (ABCC1), MRP2 (ABCC2), MRP3 (ABCC3), and MRP4 (ABCC4) have partially overlapping substrate specificities and all transport 17β-estradiol 17-(β-d-glucuronide) (E217βG). The cysteinyl leukotriene receptor 1 (CysLT1R) antagonist MK-571 inhibits all four MRP homologs, but little is known about the modulatory effects of newer leukotriene modifiers (LTMs). Here we examined the effects of seven CysLT1R- and CysLT2R-selective LTMs on E217βG uptake into MRP1-4-enriched inside-out membrane vesicles. Their effects on uptake of an additional physiologic solute were also measured for MRP1 [leukotriene C4 (LTC4)] and MRP4 [prostaglandin E2 (PGE2)]. The two CysLT2R-selective LTMs studied were generally more potent inhibitors than CysLT1R-selective LTMs, but neither class of antagonists showed any MRP selectivity. For E217βG uptake, LTM IC50s ranged from 1.2 to 26.9 μM and were most comparable for MRP1 and MRP4. The LTM rank order inhibitory potencies for E217βG versus LTC4 uptake by MRP1, and E217βG versus PGE2 uptake by MRP4, were also similar. Three of four CysLT1R-selective LTMs also stimulated MRP2 (but not MRP3) transport and thus exerted a concentration-dependent biphasic effect on MRP2. The fourth CysLT1R antagonist, LY171883, only stimulated MRP2 (and MRP3) transport but none of the MRPs were stimulated by either CysLT2R-selective LTM. We conclude that, in contrast to their CysLTR selectivity, CysLTR antagonists show no MRP homolog selectivity, and data should be interpreted cautiously if obtained from LTMs in systems in which more than one MRP is present. PMID:27068271

  17. Age- and sex-related differences of organic anion-transporting polypeptide gene expression in livers of rats

    International Nuclear Information System (INIS)

    Organic anion-transporting polypeptides (Oatps) play important roles in transporting endogenous substances and xenobiotics into the liver and are implicated in drug-drug interactions. Many factors could influence their expression and result in alterations in drug disposition, efficacy and toxicity. This study was aimed to examine the development-, aging-, and sex-dependent Oatps expression in livers of rats. The livers from SD rats during development (− 2, 1, 7, 14, 21, 28, 35, and 60 d) and aging (60, 180, 540 and/or 800 d) were collected and total RNAs were extracted, purified, and subjected to real-time PCR analysis. Total proteins were extracted for western-blot analysis. Results showed that Oatp1a1, Oatp1a4, Oatp1a5 and Oatp1b2 were all hardly detectable in fetal rat livers, low at birth, rapidly increased after weaning (21 d), and reached the peak at 60 d. The Oatps remained stable during the age between 60–180 d, and decreased at elderly (540 and/or 800 d). After birth, Oatp1a1, Oatp1a4, and Oatp1b2 were all highly expressed in liver, in contrast, Oatp1a5 expression was low. Oatp expressions are male-predominant in rat livers. In the livers of aged rats, the Oatp expression decreased and shared a consistent ontogeny pattern at the mRNA and protein level. In conclusion, this study showed that in rat liver, Oatp1a1, Oatp1a4, Oatp1a5 and Oatp1b2 gene expressions are influenced by age and gender, which could provide a basis of individual variation in drug transport, metabolism and toxicity in children, elderly and women. - Highlights: • Oatp1a1, Oatp1a4, Oatp1a5 and Oatp1b2 expression in livers of rats. • Ontogenic changes of Oatps at − 2, 1, 7, 14, 21, 28, 35, and 60 days. • Age-related changes of Oatps at 60, 180, 540, and 800 days. • Sex-difference of Oatps at the both mRNA and protein levels

  18. Age- and sex-related differences of organic anion-transporting polypeptide gene expression in livers of rats

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Wei-Yu; Xu, Shang-Fu; Zhu, Qiong-Ni; Lu, Yuan-Fu [Key Lab for Pharmacology of Ministry of Education, Zunyi Medical College, Zunyi 563003 (China); Cheng, Xing-Guo [Department of Pharmaceutical Sciences, St. John’s University, New York, NY 11439 (United States); Liu, Jie, E-mail: Jieliu@zmc.edu.cn [Key Lab for Pharmacology of Ministry of Education, Zunyi Medical College, Zunyi 563003 (China)

    2014-10-15

    Organic anion-transporting polypeptides (Oatps) play important roles in transporting endogenous substances and xenobiotics into the liver and are implicated in drug-drug interactions. Many factors could influence their expression and result in alterations in drug disposition, efficacy and toxicity. This study was aimed to examine the development-, aging-, and sex-dependent Oatps expression in livers of rats. The livers from SD rats during development (− 2, 1, 7, 14, 21, 28, 35, and 60 d) and aging (60, 180, 540 and/or 800 d) were collected and total RNAs were extracted, purified, and subjected to real-time PCR analysis. Total proteins were extracted for western-blot analysis. Results showed that Oatp1a1, Oatp1a4, Oatp1a5 and Oatp1b2 were all hardly detectable in fetal rat livers, low at birth, rapidly increased after weaning (21 d), and reached the peak at 60 d. The Oatps remained stable during the age between 60–180 d, and decreased at elderly (540 and/or 800 d). After birth, Oatp1a1, Oatp1a4, and Oatp1b2 were all highly expressed in liver, in contrast, Oatp1a5 expression was low. Oatp expressions are male-predominant in rat livers. In the livers of aged rats, the Oatp expression decreased and shared a consistent ontogeny pattern at the mRNA and protein level. In conclusion, this study showed that in rat liver, Oatp1a1, Oatp1a4, Oatp1a5 and Oatp1b2 gene expressions are influenced by age and gender, which could provide a basis of individual variation in drug transport, metabolism and toxicity in children, elderly and women. - Highlights: • Oatp1a1, Oatp1a4, Oatp1a5 and Oatp1b2 expression in livers of rats. • Ontogenic changes of Oatps at − 2, 1, 7, 14, 21, 28, 35, and 60 days. • Age-related changes of Oatps at 60, 180, 540, and 800 days. • Sex-difference of Oatps at the both mRNA and protein levels.

  19. A Small Platform for Astrophysical Research Based on the UPM-Sat 1 Satellite of the Universidad Politécnica de Madrid

    OpenAIRE

    Sanz Andres, Angel Pedro; Meseguer Ruiz, José; Perales Perales, José Manuel

    2003-01-01

    UPM-Sat 1 is a small scientific, in-orbit demonstration, educational satellite which has been designed, built, tested, integrated, launched and operated by a team of professors, students, and auxiliary personnel belonging to the Universidad Politécnica de Madrid (UPM). After completion of UPM-Sat 1 Mission a new small satellite, UPM-Sat 2, oriented to low-Earth-orbit scientific mission has been designed. In this paper the different subsystems of UPM-Sat 1 are described and the main characteri...

  20. Downregulation of organic anion transporters in rat kidney under ischemia/reperfusion-induced acute [corrected] renal failure.

    Science.gov (United States)

    Matsuzaki, T; Watanabe, H; Yoshitome, K; Morisaki, T; Hamada, A; Nonoguchi, H; Kohda, Y; Tomita, K; Inui, K; Saito, H

    2007-03-01

    The effect of acute renal failure (ARF) induced by ischemia/reperfusion (I/R) of rat kidney on the expression of organic anion transporters (OATs) was examined. The level of serum indoxyl sulfate (IS), a uremic toxin and substrate of OATs in renal tubules, shows a marked increase with the progression of ARF. However, this increase was significantly attenuated by ingestion of cobalt. The level of mRNA and protein of both rOAT1 and rOAT3 were markedly depressed in the ischemic kidney. The uptake of p-aminohippuric acid (PAH) and estrone sulfate (ES) by renal slices of ischemic rats was significantly reduced compared to control rats. Renal slices taken from ischemic rats treated with cobalt displayed significantly elevated levels of ES uptake. Cobalt intake did not affect PAH uptake, indicating the functional restoration of rOAT3 but not rOAT1. The expression of Na(+)/K(+)-ATPase was markedly depressed in the ischemic kidney, suggesting that the inward Na(+) gradient in renal tubular cells had collapsed, thereby reducing the outward gradient of alpha-ketoglutarate, a driving force of both rOATs. The decreased expression of Na(+)/K(+)-ATPase was significantly restored by cobalt treatment. Our results suggest that the downregulation of renal rOAT1 and rOAT3 could be responsible for the increase in serum IS level of ischemic rats. Cobalt treatment has a significant protective effect on ischemia-induced ARF, being accompanied by the restoration of rOAT3 and/or Na(+)/K(+)-ATPase function. PMID:17245393

  1. Comparison of inhibitory duration of grapefruit juice on organic anion-transporting polypeptide and cytochrome P450 3A4.

    Science.gov (United States)

    Tanaka, Shimako; Uchida, Shinya; Miyakawa, Sachiko; Inui, Naoki; Takeuchi, Kazuhiko; Watanabe, Hiroshi; Namiki, Noriyuki

    2013-01-01

    Recently, a new type of interaction has been reported in which fruit juices diminish oral drug bioavailability through inhibition of organic anion-transporting polypeptide (OATP). In this study, we aimed to clarify the duration of OATP inhibition by grapefruit juice (GFJ), and to compare it with the duration of GFJ-induced inhibition of cytochrome P450 (CYP) 3A4 activity. Seven healthy volunteers were enrolled in this open-label, single-sequence study. They were orally administered celiprolol (100 mg) and midazolam (15 µg/kg) with water on the control day. Three days later, they ingested GFJ (200 mL) 3 times a day for 3 d. On day 1, the same drugs were administered with GFJ. On days 3 and 7, the same drugs were administered with water. Pharmacokinetics of both drugs were evaluated on each trial day. The peak plasma concentration (Cmax) and the area under the plasma concentration-time curve from 0 to 8 h (AUC0-8) of celiprolol significantly decreased on day 1, and the mean ratios of these values and the corresponding control-day values were 0.18 and 0.25, respectively. The Cmax and AUC0-8 returned to the control levels on days 3 and 7. In contrast, AUC0-8 of midazolam were higher on days 1 and 3 than on the control day (mean ratio, 2.12 and 1.47, respectively). The AUC0-8 returned to the control level on day 7. In conclusion, results of this study indicated that the OATP inhibition caused by GFJ dissipated faster than GFJ-mediated alterations in CYP3A4 activity, which were sustained for at least 48 h. PMID:24292052

  2. Molecular-weight-dependent, anionic-substrate-preferential transport of β-lactam antibiotics via multidrug resistance-associated protein 4.

    Science.gov (United States)

    Akanuma, Shin-Ichi; Uchida, Yasuo; Ohtsuki, Sumio; Kamiie, Jun-ichi; Tachikawa, Masanori; Terasaki, Tetsuya; Hosoya, Ken-ichi

    2011-01-01

    β-Lactam antibiotics have cerebral and peripheral adverse effects. Multidrug resistance-associated protein 4 (MRP4) has been reported to transport several β-lactam antibiotics, and its expression at the blood-brain barrier also serves to limit their distribution to the brain. Therefore, the purpose of this study was to clarify the structure-activity relationship of MRP4-mediated transport of β-lactam antibiotics using MRP4-expressing Sf9 membrane vesicles. The transport activity was evaluated as MRP4-mediated transport per MRP4 protein [nL/(min·fmol MRP4 protein)] based on measurement of MRP4 protein expression by means of liquid chromatography-tandem mass spectrometry. Cefotiam showed the greatest MRP4-mediated transport activity [8.90 nL/(min·fmol MRP4 protein)] among the β-lactam antibiotics examined in this study. Measurements of differential transport activity of MRP4 for various β-lactam antibiotics indicated that (i) cephalosporins were transported via MRP4 at a greater rate than were penams, β-lactamase inhibitors, penems, or monobactams; (ii) MRP4-mediated transport activity of anionic cephalosporins was greater than that of zwitterionic cephalosporins; and (iii) higher-molecular-weight anionic β-lactam antibiotics showed greater MRP4-mediated transport activity than lower-molecular-weight ones, whereas zwitterionic β-lactam antibiotics did not show molecular weight dependency of MRP4-mediated transport. These quantitative data should prove useful for understanding MRP-related adverse effects of β-lactam antibiotics and their derivatives. PMID:21897051

  3. Evolutionary analysis of foot-and-mouth disease virus serotype SAT 1 isolates from east africa suggests two independent introductions from southern africa

    DEFF Research Database (Denmark)

    Sangula, Abraham K.; Belsham, Graham; Muwanika, Vincent B.;

    2010-01-01

    Background: In East Africa, foot-and-mouth disease virus serotype SAT 1 is responsible for occasional severe outbreaks in livestock and is known to be maintained within the buffalo populations. Little is known about the evolutionary forces underlying its epidemiology in the region. To enhance our...... 1 FMD viruses from East Africa has been determined and compared with known sequences derived from other SAT 1 viruses from sub-Saharan Africa. Purifying (negative) selection and low substitution rates characterized the SAT 1 virus isolates in East Africa. Two virus groups with probable independent...... appreciation of the epidemiological status of serotype SAT 1 virus in the region, we inferred its evolutionary and phylogeographic history by means of genealogy-based coalescent methods using 53 VP1 coding sequences covering a sampling period from 1948-2007. Results: The VP1 coding sequence of 11 serotype SAT...

  4. Evolutionary analysis of foot-and-mouth disease virus serotype SAT 1 isolates from east africa suggests two independent introductions from southern africa

    Directory of Open Access Journals (Sweden)

    Balinda Sheila N

    2010-11-01

    Full Text Available Abstract Background In East Africa, foot-and-mouth disease virus serotype SAT 1 is responsible for occasional severe outbreaks in livestock and is known to be maintained within the buffalo populations. Little is known about the evolutionary forces underlying its epidemiology in the region. To enhance our appreciation of the epidemiological status of serotype SAT 1 virus in the region, we inferred its evolutionary and phylogeographic history by means of genealogy-based coalescent methods using 53 VP1 coding sequences covering a sampling period from 1948-2007. Results The VP1 coding sequence of 11 serotype SAT 1 FMD viruses from East Africa has been determined and compared with known sequences derived from other SAT 1 viruses from sub-Saharan Africa. Purifying (negative selection and low substitution rates characterized the SAT 1 virus isolates in East Africa. Two virus groups with probable independent introductions from southern Africa were identified from a maximum clade credibility tree. One group was exclusive to Uganda while the other was present within Kenya and Tanzania. Conclusions Our results provide a baseline characterization of the inter-regional spread of SAT 1 in sub-Saharan Africa and highlight the importance of a regional approach to trans-boundary animal disease control in order to monitor circulating strains and apply appropriate vaccines.

  5. Regulation of Expression of Renal Organic Anion Transporters OAT1 and OAT3 in a Model of Ischemia/Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Christina Preising

    2015-08-01

    Full Text Available Background: Recently, we gained evidence that impairment of rOat1 and rOat3 expression induced by ischemic acute kidney injury (AKI is mediated by COX metabolites and this suppression might be critically involved in renal damage. Methods: (i Basolateral organic anion uptake into proximal tubular cells after model ischemia and reperfusion (I/R was investigated by fluorescein uptake. The putative promoter sequences from hOAT1 (SLC22A6 and hOAT3 (SCL22A8 were cloned into a reporter plasmid, transfected into HEK cells and (ii transcriptional activity was determined after model ischemia and reperfusion as a SEAP reporter gen assay. Inhibitors or antagonists were applied with the beginning of reperfusion. Results: By using inhibitors of PKA (H89 and PLC (U73122, antagonists of E prostanoid receptor type 2 (AH6809 and type 4 (L161,982, we gained evidence that I/R induced down regulation of organic anion transport is mediated by COX1 metabolites via E prostanoid receptor type 4. The latter signaling was confirmed by application of butaprost (EP2 agonist or TCS2510 (EP4 agonist to control cells. In brief, the latter signaling was verified for the transcriptional activity in the reporter gen assay established. Therein, selective inhibitors for COX1 (SC58125 and COX2 (SC560 were also applied. Conclusion: Our data show (a that COX1 metabolites are involved in the regulation of renal organic anion transport(ers after I/R via the EP4 receptor and (b that this is due to transcriptional regulation of the respective transporters. As the promoter sequences cloned were of human origin and expressed in a human renal epithelial cell line we (c hypothesize that the regulatory mechanisms described after I/R is meaningful for humans as well.

  6. A study on the electron transport properties of ZnON semiconductors with respect to the relative anion content

    Science.gov (United States)

    Park, Jozeph; Kim, Yang Soo; Ok, Kyung-Chul; Park, Yun Chang; Kim, Hyun You; Park, Jin-Seong; Kim, Hyun-Suk

    2016-04-01

    High-mobility zinc oxynitride (ZnON) semiconductors were grown by RF sputtering using a Zn metal target in a plasma mixture of Ar, N2, and O2 gas. The RF power and the O2 to N2 gas flow rates were systematically adjusted to prepare a set of ZnON films with different relative anion contents. The carrier density was found to be greatly affected by the anion composition, while the electron mobility is determined by a fairly complex mechanism. First-principles calculations indicate that excess vacant nitrogen sites (VN) in N-rich ZnON disrupt the local electron conduction paths, which may be restored by having oxygen anions inserted therein. The latter are anticipated to enhance the electron mobility, and the exact process parameters that induce such a phenomenon can only be found experimentally. Contour plots of the Hall mobility and carrier density with respect to the RF power and O2 to N2 gas flow rate ratio indicate the existence of an optimum region where maximum electron mobility is obtained. Using ZnON films grown under the optimum conditions, the fabrication of high-performance devices with field-effect mobility values exceeding 120 cm2/Vs is demonstrated based on simple reactive RF sputtering methods.

  7. Arsenic and Mercury Containing Traditional Chinese Medicine (Realgar and Cinnabar) Strongly Inhibit Organic Anion Transporters, Oat1 and Oat3, In Vivo in Mice

    Science.gov (United States)

    Yu, Wen-Hao; Zhang, Na; Qi, Jin-Feng; Sun, Chen; Wang, Yong-Hui; Lin, Mei

    2015-01-01

    Toxic heavy metals, including mercury (Hg) and arsenic (As), accumulate preferentially in kidneys and always cause acute renal failure. The aim of this study was to investigate whether these samples affect organic anion transporters, Oat1 and Oat3, in vivo in mice kidney. Mice (n = 10) were orally treated with investigational samples. After last administration, all mice were i.v. p-aminohippuric acid (PAH), and the blood and kidneys samples were collected. The concentrations of PAH were quantified by spectrophotometry. mRNA expressions of Oat1 and Oat3 were assayed by real-time PCR. In comparison with corresponding control, major pharmacokinetic parameters of PAH in sera were significantly changed by investigational samples (p Oat1 and Oat3 mRNA expression were significantly inhibited in investigational sample groups. Arsenic and mercury containing traditional Chinese medicine (Realgar and Cinnabar) probably induce kidney damage through inhibiting several members of the organic anion transporters (such as OAT1 and OAT3). PMID:26788513

  8. Transcriptional regulation of organic anion transporting polypeptide SLCO4C1 as a new therapeutic modality to prevent chronic kidney disease.

    Science.gov (United States)

    Suzuki, Takehiro; Toyohara, Takafumi; Akiyama, Yasutoshi; Takeuchi, Yoichi; Mishima, Eikan; Suzuki, Chitose; Ito, Sadayoshi; Soga, Tomoyoshi; Abe, Takaaki

    2011-09-01

    Uremic toxins accumulate in patients with chronic kidney diseases (CKDs) and cause further progression of renal damage and cardiovascular diseases. Recently, it was reported that some of the organic anion transporting polypeptides (OATPs) and the organic anion transporters (OATs) are involved in the renal elimination of uremic toxins. SLCO4C1 is the only OATP expressed at the basolateral side of proximal tubular cells in human kidney, and it mediates the excretion of uremic toxins. The overexpression of human SLCO4C1 in rat kidney promotes the renal excretion of uremic toxins and reduces hypertension, cardiomegaly, and renal inflammation in renal failure. Statins induce SLCO4C1 expression thorough transcriptional factor Aryl hydrocarbon receptor through binding of the xenobiotic responsive element at its promoter region. The administration of statin in a rat renal failure model facilitated the elimination of uremic toxins and mitigated organ damage. In addition, metabolomic analysis of rat renal failure models and patients with CKD by capillary electrophoresis-mass spectrometry is a useful method for identifying new uremic solutes and explores surrogate biomarkers for detecting the progression of early stage CKD. PMID:21656517

  9. Design and analysis of algorithms for enhancing the quality and the resolution of Dubai Sat-1 images

    Science.gov (United States)

    Al-Mansoori, Saeed

    2011-11-01

    DubaiSat-1 (DS1) captures multispectral images with 5-meter resolution using three visible bands red (420 to 510 nm), green (510 to 580 nm), blue (600 to 720 nm) and one near-IR band (760 to 890 nm). It also has a panchromatic channel with 2.5-meter resolution (420 to 720 nm). [1] Under certain conditions, degradation in quality might occur over DS1 captured images. The aim of this project is to enhance the quality of the image in terms of resolution, sharpness and color quality. It is well known that the enhancement procedure is a very difficult task due to the significant noise increase resulted from any sharpening action. Moreover, sometimes the color of the captured images might become saturated, thus some areas will be given false coloring (i.e., some colors will be presented as gray instead of their original colors).

  10. Demonstrating soil moisture remote sensing with observations from the UK TechDemoSat-1 satellite mission

    Science.gov (United States)

    Chew, Clara; Shah, Rashmi; Zuffada, Cinzia; Hajj, George; Masters, Dallas; Mannucci, Anthony J.

    2016-04-01

    The ability of spaceborne Global Navigation Satellite System (GNSS) bistatic radar receivers to sense changes in soil moisture is investigated using observations from the low Earth orbiting UK TechDemoSat-1 satellite (TDS-1). Previous studies using receivers on aircraft or towers have shown that ground-reflected GNSS signals are sensitive to changes in soil moisture, though the ability to sense this variable from space has yet to be quantified. Data from TDS-1 show a 7 dB sensitivity of reflected signals to temporal changes in soil moisture. If the effects of surface roughness and vegetation on the reflected signals can be quantified, spaceborne GNSS bistatic radar receivers could provide soil moisture on relatively small spatial and temporal scales.

  11. [Dynamics of ultrastructure changes in sheet plate fiber flax with braking transport assimilate by nitrate-anion].

    Science.gov (United States)

    Abdrakhimov, F A; Batasheva, S N; Bakirova, G G; Chikov, V I

    2008-01-01

    Changes in leaf mesophyll cell ultrastructure under nitrate feeding into the apoplast of common flax (Linum usitatissimum L.) in the form of 50 mM KNO3 solution were studied. In 30 min after the beginning of nitrate feeding through the transpiration water stream, swelling of mitochondrial and microbodies, clarification of their matrices, and curling of dictyosome discs into annular structures were observed. These events characterized symplastic domain formed by mesophyll, bundle sheath and phloem parenchyma cells, and were not found in companion cell-sieve element complex. Simultaneously, formation of large central vacuoles in companion cells was noted. Restoration of organelle structures in assimilating cells and phloem parenchyma in 1-2 h after treatment was accompanied by enhancement of morphological changes in phloem elements and companion cells and signs of plasmolysis in the mesophyll cells. It was supposed that the two-phase character of changes in leaf organelle ultrastructure and photosynthesis might reflect duality of leaf cell response to nitrate ion. The rapid alterations of the structure can be coupled with direct influence of the anion on cell metabolism and(or) with signal-regulatory functions of oxidized nitrogen forms, while the slower ones reflect the result of suppression of photoassimilate export from leaves by the anion. PMID:18822790

  12. Effect of SLC26 anion transporter disease-causing mutations on the stability of the homologous STAS domain of E. coli DauA (YchM).

    Science.gov (United States)

    Bai, Xiaoyun; Moraes, Trevor F; Reithmeier, Reinhart A F

    2016-03-01

    The human solute carrier 26 (SLC26) family of anion transporters consists of ten members that are found in various organs in the body including the stomach, intestine, kidney, thyroid and ear where they transport anions including bicarbonate, chloride and sulfate, typically in an exchange mode. Mutations in these genes cause a plethora of diseases such as diastrophic dysplasia affecting sulfate uptake into chondrocytes (SLC26A2), congenital chloride-losing diarrhoea (SLC26A3) affecting chloride secretion in the intestine and Pendred's syndrome (SLC26A4) resulting in hearing loss. To understand how these mutations affect the structures of the SLC26 membrane proteins and their ability to function properly, 12 human disease-causing mutants from SLC26A2, SLC26A3 and SLC26A4 were introduced into the equivalent sites of the sulfate transporter anti-sigma factor antagonist (STAS) domain of a bacterial homologue SLC26 protein DauA (YchM). Biophysical analyses including size-exclusion chromatography, circular dichroism (CD), differential scanning fluorimetry (DSF) and tryptophan fluorescence revealed that most mutations caused protein instability and aggregation. The mutation A463K, equivalent to N558K in human SLC26A4, which is located within α-helix 1 of the DauA STAS domain, stabilized the protein. CD measurements showed that most disease-related mutants had a mildly reduced helix content, but were more sensitive to thermal denaturation. Fluorescence spectroscopy showed that the mutants had more open structures and were more readily denatured by urea, whereas DSF indicated more labile folds. Overall, we conclude that the disease-associated mutations destabilized the STAS domain resulting in an increased propensity to misfold and aggregate. PMID:26635355

  13. Genetic polymorphisms and function of the organic anion-transporting polypeptide 1A2 and its clinical relevance in drug disposition.

    Science.gov (United States)

    Zhou, Yinhui; Yuan, Jingjing; Li, Zhisong; Wang, Zhongyu; Cheng, Dan; Du, Yingying; Li, Wenlu; Kan, Quancheng; Zhang, Wei

    2015-01-01

    The solute carrier organic anion-transporting polypeptides (OATPs) are a family of transporter proteins that have been extensively recognized as key determinants of absorption, distribution, metabolism and excretion of various drugs because of their broad substrate specificity and wide tissue distribution as well as the involvement of drug-drug interaction. Human OATP1A2 is a drug uptake transporter known for its broad substrate specificity, including many drugs in clinical use. OATP1A2 expression has been detected in the intestine, liver, brain and kidney. A considerable number of single nucleotide polymorphisms have been found for the OATP1A2 gene. A number of studies have shown that the cellular uptake and pharmacokinetic behavior of some drugs may be impaired in the case of certain OATP1A2 variants. Interestingly, some studies show that the mRNA expression of OATP1A2 is nearly 10-fold higher in breast cancer compared with adjacent healthy breast tissues. This review is, therefore, focused on the genetic polymorphisms, function and clinical relevance of OATP1A2 as well as on the substrates transported by it. PMID:25924632

  14. Identification of novel inhibitors of the steroid sulfate carrier 'sodium-dependent organic anion transporter' SOAT (SLC10A6) by pharmacophore modelling.

    Science.gov (United States)

    Grosser, Gary; Baringhaus, Karl-Heinz; Döring, Barbara; Kramer, Werner; Petzinger, Ernst; Geyer, Joachim

    2016-06-15

    The sodium-dependent organic anion transporter SOAT specifically transports sulfated steroid hormones and is supposed to play a role in testicular steroid regulation and male fertility. The present study aimed to identify novel specific SOAT inhibitors for further in vitro and in vivo studies on SOAT function. More than 100 compounds of different molecular structures were screened for inhibition of the SOAT-mediated transport of dehydroepiandrosterone sulfate in stably transfected SOAT-HEK293 cells. Twenty-five of these with IC50 values covering four orders of magnitude were selected as training set for 3D pharmacophore modelling. The SOAT pharmacophore features were calculated by CATALYST and consist of three hydrophobic sites and two hydrogen bond acceptors. By substrate database screening, compound T 0511-1698 was predicted as a novel SOAT inhibitor with an IC50 of 15 μM. This value was confirmed by cell-based transport assays. Therefore, the developed SOAT pharmacophore model demonstrated its suitability in predicting novel SOAT inhibitors. PMID:27033324

  15. Multivariate analysis of the transport in an ion exchange membrane bioreactor for removal of anionic micropollutants from drinking water.

    Science.gov (United States)

    Ricardo, A R; Velizarov, S; Crespo, J G; Reis, M A M

    2011-01-01

    The present study focuses on investigating the effects of biological compartment conditions on the transport of nitrate and perchlorate in an Ion Exchange Membrane Bioreactor (IEMB). In this hybrid process, the transport depends not only on the membrane properties but also on the biological compartment conditions. The experiments were planned according to the Plackett-Burman statistical design in order to cover a broader range of experimental conditions, under which a previously developed mechanistic transport model was not able to predict correctly the transport fluxes of the target pollutants. Using Principal Component Analysis, it was possible to identify not only the concentrations of target (nitrate and perchlorate) and of major driving counter-ion (chloride) but also those of some biomedium components (e.g. ammonia, ethanol and sulphate) as variables that affect the transport rate of micropollutants across the membrane. These conclusions are based on the loadings of the two first principal components that describe 84% of the data variance. The present study also revealed that the hydraulic retention time and the hydrodynamic conditions in the biocompartment have a minor contribution to the micropollutants transport. The results obtained are important for process optimization purposes. PMID:21977639

  16. Organic anion and cation SLC22 "drug" transporter (Oat1, Oat3, and Oct1 regulation during development and maturation of the kidney proximal tubule.

    Directory of Open Access Journals (Sweden)

    Thomas F Gallegos

    Full Text Available Proper physiological function in the pre- and post-natal proximal tubule of the kidney depends upon the acquisition of selective permeability, apical-basolateral epithelial polarity and the expression of key transporters, including those involved in metabolite, toxin and drug handling. Particularly important are the SLC22 family of transporters, including the organic anion transporters Oat1 (originally identified as NKT and Oat3 as well as the organic cation transporter Oct1. In ex vivo cultures of metanephric mesenchyme (MM; the embryonic progenitor tissue of the nephron Oat function was evident before completion of nephron segmentation and corresponded with the maturation of tight junctions as measured biochemically by detergent extractability of the tight junction protein, ZO-1. Examination of available time series microarray data sets in the context of development and differentiation of the proximal tubule (derived from both in vivo and in vitro/ex vivo developing nephrons allowed for correlation of gene expression data to biochemically and functionally defined states of development. This bioinformatic analysis yielded a network of genes with connectivity biased toward Hnf4α (but including Hnf1α, hyaluronic acid-CD44, and notch pathways. Intriguingly, the Oat1 and Oat3 genes were found to have strong temporal co-expression with Hnf4α in the cultured MM supporting the notion of some connection between the transporters and this transcription factor. Taken together with the ChIP-qPCR finding that Hnf4α occupies Oat1, Oat3, and Oct1 proximal promoters in the in vivo differentiating rat kidney, the data suggest a network of genes with Hnf4α at its center plays a role in regulating the terminal differentiation and capacity for drug and toxin handling by the nascent proximal tubule of the kidney.

  17. A particle-based model of size or anion exclusion with application to microbial transport in Porous Media

    International Nuclear Information System (INIS)

    This paper presents a novel approach to the quantification of pore-scale exclusion processes, based on the truncation of the distribution of local dispersive displacements in a random-walk particle model. This approach increases the mean velocity of colloidal-sized particles relative to inert solute tracers, and decreases the apparent dispersion. An equivalent continuum (concentration-based) model, with modified velocity and dispersion parameters, is derived. The model was applied to the results of laboratory experiments on bacterial transport in intact cores from a research site near Oyster, Virginia. The significant observed decrease in bacterial arrival times relative to a bromide tracer was closely reproduced by the particle-based model with modest degrees of truncation (8% maximum). The approach provides a conceptually consistent means of incorporating the exclusion process into groundwater transport models

  18. Expression of Organic Anion Transporters 1 and 3 in the Ovine Fetal Brain During the Latter Half of Gestation

    OpenAIRE

    Cousins, Roderick; Charles E. Wood

    2010-01-01

    Development and maturation of the fetal brain is critical for homeostasis in utero, responsiveness to fetal stress and, in ruminants, control of the timing of birth. In the sheep, as in the human, the placenta secretes estrogen and other signaling molecules into both the fetal and maternal blood, molecules whose entry or exit across the blood-brain barrier is likely to be facilitated by transporters. The purpose of this study was to test the hypothesis that the ovine fetal brain expresses org...

  19. Casein Kinase 2 Is a Novel Regulator of the Human Organic Anion Transporting Polypeptide 1A2 (OATP1A2) Trafficking.

    Science.gov (United States)

    Chan, Ting; Cheung, Florence Shin Gee; Zheng, Jian; Lu, Xiaoxi; Zhu, Ling; Grewal, Thomas; Murray, Michael; Zhou, Fanfan

    2016-01-01

    Human organic anion transporting polypeptides (OATPs) mediate the influx of many important drugs into cells. Casein kinase 2 (CK2) is a critical protein kinase that phosphorylates >300 protein substrates and is dysregulated in a number of disease states. Among the CK2 substrates are several transporters, although whether this includes human OATPs has not been evaluated. The current study was undertaken to evaluate the regulation of human OATP1A2 by CK2. HEK-239T cells in which OATP1A2 was overexpressed were treated with CK2 specific inhibitors or transfected with CK2 specific siRNA, and the activity, expression, and subcellular trafficking of OATP1A2 was evaluated. CK2 inhibition decreased the uptake of the prototypic OATP1A2 substrate estrone-3-sulfate (E3S). Kinetic studies revealed that this was due to a decrease in the maximum velocity (Vmax) of E3S uptake, while the Michaelis constant was unchanged. The cell surface expression, but not the total cellular expression of OATP1A2, was impaired by CK2 inhibition and knockdown of the catalytic α-subunits of CK2. CK2 inhibition decreased the internalization of OATP1A2 via a clathrin-dependent pathway, decreased OATP1A2 recycling, and likely impaired OATP1A2 targeting to the cell surface. Consistent with these findings, CK2 inhibition also disrupted the colocalization of OATP1A2 and Rab GTPase (Rab)4-, Rab8-, and Rab9-positive endosomal and secretory vesicles. Taken together, CK2 has emerged as a novel regulator of the subcellular trafficking and stability of OATP1A2. Because OATP1A2 transports many molecules of physiological and pharmacological importance, the present data may inform drug selection in patients with diseases in which CK2 and OATP1A2 are dysregulated. PMID:26580496

  20. Organic Anion Transporting Polypeptide (OATP)2B1 Contributes to Gastrointestinal Toxicity of Anticancer Drug SN-38, Active Metabolite of Irinotecan Hydrochloride.

    Science.gov (United States)

    Fujita, Daichi; Saito, Yoshimasa; Nakanishi, Takeo; Tamai, Ikumi

    2016-01-01

    Gastrointestinal toxicity, such as late-onset diarrhea, is a significant concern in irinotecan hydrochloride (CPT-11)-containing regimens. Prophylaxis of late-onset diarrhea has been reported with use of Japanese traditional (Kampo) medicine containing baicalin and with the antibiotic cefixime, and this has been explained in terms of inhibition of bacterial deconjugation of SN-38-glucuronide since unconjugated SN-38 (active metabolite of CPT-11) is responsible for the gastrointestinal toxicity. It is also prerequisite for SN-38 to be accumulated in intestinal tissues to exert toxicity. Based on the fact that liver-specific organic anion transporting polypeptide (OATP)1B1, a member of the same family as OATP2B1, is known to be involved in hepatic transport of SN-38, we hypothesized that intestinal transporter OATP2B1 contributes to the accumulation of SN-38 in gastrointestinal tissues, and its inhibition would help prevent associated toxicity. We found that uptake of SN-38 by OATP2B1-expressing Xenopus oocytes was significantly higher than that by control oocytes. OATP2B1-mediated uptake of SN-38 was saturable, pH dependent, and decreased in the presence of baicalin, cefixime, or fruit juices such as apple juice. In vivo gastrointestinal toxicity of SN-38 in mice caused by oral administration for consecutive 5 days was prevented by coingestion of apple juice. Thus, OATP2B1 contributes to the uptake of SN-38 by intestinal tissues, triggering gastrointestinal toxicity. So, in addition to the reported inhibition of bacterial β-glucuronidase by cefixime or baicalin, inhibition of OATP2B1 may also contribute to prevention of gastrointestinal toxicity. Apple juice may be helpful for prophylaxis of late-onset diarrhea observed in CPT-11 therapy without disturbance of the intestinal microflora. PMID:26526067

  1. The Antimicrobial Agent Fusidic Acid Inhibits Organic Anion Transporting Polypeptide-Mediated Hepatic Clearance and May Potentiate Statin-Induced Myopathy.

    Science.gov (United States)

    Eng, Heather; Scialis, Renato J; Rotter, Charles J; Lin, Jian; Lazzaro, Sarah; Varma, Manthena V; Di, Li; Feng, Bo; West, Michael; Kalgutkar, Amit S

    2016-05-01

    Chronic treatment of methicillin-resistantStaphylococcus aureusstrains with the bacteriostatic agent fusidic acid (FA) is frequently associated with myopathy including rhabdomyolysis upon coadministration with statins. Because adverse effects with statins are usually the result of drug-drug interactions, we evaluated the inhibitory effects of FA against human CYP3A4 and clinically relevant drug transporters such as organic anion transporting polypeptides OATP1B1 and OATP1B3, multidrug resistant protein 1, and breast cancer resistance protein, which are involved in the oral absorption and/or systemic clearance of statins including atorvastatin, rosuvastatin, and simvastatin. FA was a weak reversible (IC50= 295 ± 1.0μM) and time-dependent (KI= 216 ± 41μM andkinact= 0.0179 ± 0.001 min(-1)) inhibitor of CYP3A4-catalyzed midazolam-1'-hydroxylase activity in human liver microsomes. FA demonstrated inhibition of multidrug resistant protein 1-mediated digoxin transport with an IC50value of 157 ± 1.0μM and was devoid of breast cancer resistance protein inhibition (IC50> 500μM). In contrast, FA showed potent inhibition of OATP1B1- and OATP1B3-specific rosuvastatin transport with IC50values of 1.59μM and 2.47μM, respectively. Furthermore, coadministration of oral rosuvastatin and FA to rats led to an approximately 19.3-fold and 24.6-fold increase in the rosuvastatin maximum plasma concentration and area under the plasma concentration-time curve, respectively, which could be potentially mediated through inhibitory effects of FA on rat Oatp1a4 (IC50= 2.26μM) and Oatp1b2 (IC50= 4.38μM) transporters, which are responsible for rosuvastatin uptake in rat liver. The potent inhibition of human OATP1B1/OATP1B3 by FA could attenuate hepatic uptake of statins, resulting in increased blood and tissue concentrations, potentially manifesting in musculoskeletal toxicity. PMID:26888941

  2. Molecular physiology of EAAT anion channels.

    Science.gov (United States)

    Fahlke, Christoph; Kortzak, Daniel; Machtens, Jan-Philipp

    2016-03-01

    Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system. After release from presynaptic nerve terminals, glutamate is quickly removed from the synaptic cleft by a family of five glutamate transporters, the so-called excitatory amino acid transporters (EAAT1-5). EAATs are prototypic members of the growing number of dual-function transport proteins: they are not only glutamate transporters, but also anion channels. Whereas the mechanisms underlying secondary active glutamate transport are well understood at the functional and at the structural level, mechanisms and cellular roles of EAAT anion conduction have remained elusive for many years. Recently, molecular dynamics simulations combined with simulation-guided mutagenesis and experimental analysis identified a novel anion-conducting conformation, which accounts for all experimental data on EAAT anion currents reported so far. We here review recent findings on how EAATs accommodate a transporter and a channel in one single protein. PMID:26687113

  3. The volume-regulated anion channel is formed by LRRC8 heteromers – molecular identification and roles in membrane transport and physiology.

    Science.gov (United States)

    Stauber, Tobias

    2015-09-01

    Cellular volume regulation is fundamental for numerous physiological processes. The volume-regulated anion channel, VRAC, plays a crucial role in regulatory volume decrease. This channel, which is ubiquitously expressed in vertebrates, has been vastly characterized by electrophysiological means. It opens upon cell swelling and conducts chloride and arguably organic osmolytes. VRAC has been proposed to be critically involved in various cellular and organismal functions, including cell proliferation and migration, apoptosis, transepithelial transport, swelling-induced exocytosis and intercellular communication. It may also play a role in pathological states like cancer and ischemia. Despite many efforts, the molecular identity of VRAC had remained elusive for decades, until the recent discovery of heteromers of LRRC8A with other LRRC8 family members as an essential VRAC component. This identification marks a starting point for studies on the structure-function relation, for molecular biological investigations of its cell biology and for re-evaluating the physiological roles of VRAC. This review recapitulates the identification of LRRC8 heteromers as VRAC components, depicts the similarities between LRRC8 proteins and pannexins, and discussed whether VRAC conducts larger osmolytes. Furthermore, proposed physiological functions of VRAC and the present knowledge about the physiological significance of LRRC8 proteins are summarized and collated. PMID:25868000

  4. Organic anion transporting polypeptides OATP1B1 and OATP1B3 and their genetic variants influence the pharmacokinetics and pharmacodynamics of raloxifene

    Directory of Open Access Journals (Sweden)

    Trdan Lušin Tina

    2012-04-01

    Full Text Available Abstract Background Raloxifene, a selective estrogen receptor modulator, exhibits quite large and unexplained interindividual variability in pharmacokinetics and pharmacodynamics. The aim of this study was to determine the role of organic-anion transporting polypeptides OATP1B1 and OATP1B3 and their genetic variants in the pharmacokinetics and pharmacodynamics of raloxifene. Methods To test the role of OATP1B1 and OATP1B3 transporters on hepatic uptake of raloxifene and its metabolites an in vitro model of Chinese Hamster Ovary cells expressing OATP1B1 or OATP1B3 was employed. The influence of OATP1B1 and OATP1B3 genetic variants on in vivo pharmacokinetics and pharmacodynamics was evaluated in 53 osteoporotic postmenopausal women treated with raloxifene. Results Our in vitro results showed that raloxifene and two of the three metabolites, raloxifene-4'-β-glucuronide (M2 and raloxifene-6,4'-diglucuronide (M3, interact with OATP1B1 and OATP1B3. Higher M3 and total raloxifene serum concentrations in patients correlated with lower serum levels of bone resorption marker, serum C-terminal telopeptide fragments of type I collagen, indicating a higher antiresorptive effect of raloxifene. Higher concentrations of M2 correlated with higher increase of lumbar spine bone mineral density supporting the raloxifene vertebral fracture specific protection effect. Finally, raloxifene, M3 and total raloxifene serum concentrations were significantly higher in patients with SLCO1B1 c.388A > G polymorphism and *1b haplotype implicating a considerable genetic effect on pharmacokinetics and pharmacodynamics of raloxifene. Conclusions These findings indicate that SLCO1B1 c.388A > G polymorphism could play an important role in pharmacokinetics and pharmacodynamics of raloxifene.

  5. Comparative effects of nodularin and microcystin-LR in zebrafish: 1. Uptake by organic anion transporting polypeptide Oatp1d1 (Slco1d1).

    Science.gov (United States)

    Faltermann, Susanne; Prétôt, René; Pernthaler, Jakob; Fent, Karl

    2016-02-01

    Microcystin-LR (MC-LR) and nodularin are hepatotoxins produced by several cyanobacterial species. Their toxicity is based on active cellular uptake and subsequent inhibition of protein phosphatases PP1/2A, leading to hyperphosphorylation and cell death. To date, uptake of MC-LR and nodularin in fish is poorly understood. Here, we investigated the role of the organic anion transporting polypeptide Oatp1d1 in zebrafish (drOatp1d1, Slco1d1) in cellular uptake in zebrafish. We stably transfected CHO and HEK293 cell lines expressing drOatp1d1. In both transfectants, uptake of MC-LR and nodularin was demonstrated by competitive inhibition of uptake with fluorescent substrate lucifer yellow. Direct uptake of MC-LR was demonstrated by immunostaining, and indirectly by the high cytotoxicity in stable transfectants. By means of a synthesized fluorescent labeled MC-LR derivative, direct uptake was further confirmed in HEK293 cells expressing drOatp1d1. Additionally, uptake and toxicity was investigated in the permanent zebrafish liver cell line ZFL. These cells had only a low relative abundance of drOatp1d1, drOatp2b1 and drOatp1f transcripts, which correlated with the lack of MC-LR induced cytotoxicity and transcriptional changes of genes indicative of endoplasmic reticulum stress, a known effect of this toxin. Our study demonstrates that drOatp1d1 functions as an uptake transporter for both MC-LR and nodularin in zebrafish. PMID:26769064

  6. The glutamate aspartate transporter (GLAST) mediates L-glutamate-stimulated ascorbate-release via swelling-activated anion channels in cultured neonatal rodent astrocytes.

    Science.gov (United States)

    Lane, Darius J R; Lawen, Alfons

    2013-03-01

    Vitamin C (ascorbate) plays important neuroprotective and neuromodulatory roles in the mammalian brain. Astrocytes are crucially involved in brain ascorbate homeostasis and may assist in regenerating extracellular ascorbate from its oxidised forms. Ascorbate accumulated by astrocytes can be released rapidly by a process that is stimulated by the excitatory amino acid, L-glutamate. This process is thought to be neuroprotective against excitotoxicity. Although of potential clinical interest, the mechanism of this stimulated ascorbate-release remains unknown. Here, we report that primary cultures of mouse and rat astrocytes release ascorbate following initial uptake of dehydroascorbate and accumulation of intracellular ascorbate. Ascorbate-release was not due to cellular lysis, as assessed by cellular release of the cytosolic enzyme lactate dehydrogenase, and was stimulated by L-glutamate and L-aspartate, but not the non-excitatory amino acid L-glutamine. This stimulation was due to glutamate-induced cellular swelling, as it was both attenuated by hypertonic and emulated by hypotonic media. Glutamate-stimulated ascorbate-release was also sensitive to inhibitors of volume-sensitive anion channels, suggesting that the latter may provide the conduit for ascorbate efflux. Glutamate-stimulated ascorbate-release was not recapitulated by selective agonists of either ionotropic or group I metabotropic glutamate receptors, but was completely blocked by either of two compounds, TFB-TBOA and UCPH-101, which non-selectively and selectively inhibit the glial Na(+)-dependent excitatory amino acid transporter, GLAST, respectively. These results suggest that an impairment of astrocytic ascorbate-release may exacerbate neuronal dysfunction in neurodegenerative disorders and acute brain injury in which excitotoxicity and/or GLAST deregulation have been implicated. PMID:22886112

  7. The impact of Organic Anion-Transporting Polypeptides (OATPs) on disposition and toxicity of antitumor drugs: Insights from knockout and humanized mice.

    Science.gov (United States)

    Durmus, Selvi; van Hoppe, Stéphanie; Schinkel, Alfred H

    2016-07-01

    It is now widely accepted that organic anion-transporting polypeptides (OATPs), especially members of the OATP1A/1B family, can have a major impact on the disposition and elimination of a variety of endogenous molecules and drugs. Owing to their prominent expression in the sinusoidal plasma membrane of hepatocytes, OATP1B1 and OATP1B3 play key roles in the hepatic uptake and plasma clearance of a multitude of structurally diverse anti-cancer and other drugs. Here, we present a thorough assessment of the currently available OATP1A and OATP1B knockout and transgenic mouse models as key tools to study OATP functions in vivo. We discuss recent studies using these models demonstrating the importance of OATPs, primarily in the plasma and hepatic clearance of anticancer drugs such as taxanes, irinotecan/SN-38, methotrexate, doxorubicin, and platinum compounds. We further discuss recent work on OATP-mediated drug-drug interactions in these mouse models, as well as on the role of OATP1A/1B proteins in the phenomenon of hepatocyte hopping, an efficient and flexible way of liver detoxification for both endogenous and exogenous substrates. Interestingly, glucuronide conjugates of both the heme breakdown product bilirubin and the protein tyrosine kinase-targeted anticancer drug sorafenib are strongly affected by this process. The clinical relevance of variation in OATP1A/1B activity in patients has been previously revealed by the effects of polymorphic variants and drug-drug interactions on drug toxicity. The development of in vivo tools to study OATP1A/1B functions has greatly advanced our mechanistic understanding of their functional role in drug pharmacokinetics, and their implications for therapeutic efficacy and toxic side effects of anticancer and other drug treatments. PMID:27449599

  8. Low doses of ochratoxin A upregulate the protein expression of organic anion transporters Oat1, Oat2, Oat3 and Oat5 in rat kidney cortex

    International Nuclear Information System (INIS)

    Mycotoxin ochratoxin A (OTA) is nephrotoxic in various animal species. In rodents, OTA intoxication impairs various proximal tubule (PT) functions, including secretion of p-aminohippurate (PAH), possibly via affecting the renal organic anion (OA) transporters (Oat). However, an effect of OTA on the activity/expression of specific Oats in the mammalian kidney has not been reported. In this work, male rats were gavaged various doses of OTA every 2nd day for 10 days, and in their kidneys we studied: tubule integrity by microscopy, abundance of basolateral (rOat1, rOat3) and brush-border (rOat2, rOat5) rOat proteins by immunochemical methods, and expression of rOats mRNA by RT-PCR. The OTA treatment caused: a) dose-dependent damage of the cells in S3 segments of medullary rays, b) dual effect upon rOats in PT: low doses (50-250 μg OTA/kg b.m.) upregulated the abundance of all rOats, while a high dose (500 μg OTA/kg b.m.) downregulated the abundance of rOat1, and c) unchanged mRNA expression for all rOats at low OTA doses, and its downregulation at high OTA dose. Changes in the expression of renal Oats were associated with enhanced OTA accumulation in tissue and excretion in urine, whereas the indicators of oxidative stress either remained unchanged (malondialdehyde, glutathione, 8-hydroxydeoxyguanosine) or became deranged (microtubules). While OTA accumulation and downregulation of rOats in the kidney are consistent with the previously reported impaired renal PAH secretion in rodents intoxicated with high OTA doses, the post-transcriptional upregulation of Oats at low OTA doses may contribute to OTA accumulation and development of nephrotoxicity.

  9. Pu Anion Exchange Process Intensification

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-08

    This project seeks to improve the efficiency of the plutonium anion-exchange process for purifying Pu through the development of alternate ion-exchange media. The objective of the project in FY15 was to develop and test a porous foam monolith material that could serve as a replacement for the current anion-exchange resin, Reillex® HPQ, used at the Savannah River Site (SRS) for purifying Pu. The new material provides advantages in efficiency over the current resin by the elimination of diffusive mass transport through large granular resin beads. By replacing the large resin beads with a porous foam there is much more efficient contact between the Pu solution and the anion-exchange sites present on the material. Several samples of a polystyrene based foam grafted with poly(4-vinylpyridine) were prepared and the Pu sorption was tested in batch contact tests.

  10. Renal elimination of organic anions in cholestasis

    Institute of Scientific and Technical Information of China (English)

    Adriana Mónica Tortes

    2008-01-01

    The disposition of most drugs is highly dependent on specialized transporters.OAT1 and OAT3 are two organic anion transporters expressed in the basolateral membrane of renal proximal tubule cells,identified as contributors to xenobiotic and endogenous organic anion secretion.It is well known that cholestasis may cause renal damage.Impairment of kidney function produces modifications in the renal elimination of drugs.Recent studies have demonstrated that the renal abundance of OAT1 and OAT3 plays an important role in the renal elimination of organic anions in the presence of extrahepatic cholestasis.Time elapsed after obstructive cholestasis has an important impact on the regulation of both types of organic anion transporters.The renal expression of OAT1 and OAT3 should be taken into account in order to improve pharmacotherapeutic efficacy and to prevent drug toxicity during the onset of this hepatic disease.

  11. Anion binding in biological systems

    Energy Technology Data Exchange (ETDEWEB)

    Feiters, Martin C [Department of Organic Chemistry, Institute for Molecules and Materials, Faculty of Science, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Meyer-Klaucke, Wolfram [EMBL Hamburg Outstation at DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Kostenko, Alexander V; Soldatov, Alexander V [Faculty of Physics, Southern Federal University, Sorge 5, Rostov-na-Donu, 344090 (Russian Federation); Leblanc, Catherine; Michel, Gurvan; Potin, Philippe [Centre National de la Recherche Scientifique and Universite Pierre et Marie Curie Paris-VI, Station Biologique de Roscoff, Place Georges Teissier, BP 74, F-29682 Roscoff cedex, Bretagne (France); Kuepper, Frithjof C [Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Oban, Argyll PA37 1QA, Scotland (United Kingdom); Hollenstein, Kaspar; Locher, Kaspar P [Institute of Molecular Biology and Biophysics, ETH Zuerich, Schafmattstrasse 20, Zuerich, 8093 (Switzerland); Bevers, Loes E; Hagedoorn, Peter-Leon; Hagen, Wilfred R, E-mail: m.feiters@science.ru.n [Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft (Netherlands)

    2009-11-15

    We compare aspects of biological X-ray absorption spectroscopy (XAS) studies of cations and anions, and report on some examples of anion binding in biological systems. Brown algae such as Laminaria digitata (oarweed) are effective accumulators of I from seawater, with tissue concentrations exceeding 50 mM, and the vanadate-containing enzyme haloperoxidase is implicated in halide accumulation. We have studied the chemical state of iodine and its biological role in Laminaria at the I K edge, and bromoperoxidase from Ascophyllum nodosum (knotted wrack) at the Br K edge. Mo is essential for many forms of life; W only for certain archaea, such as Archaeoglobus fulgidus and the hyperthermophilic archaeon Pyrococcus furiosus, and some bacteria. The metals are bound and transported as their oxo-anions, molybdate and tungstate, which are similar in size. The transport protein WtpA from P. furiosus binds tungstate more strongly than molybdate, and is related in sequence to Archaeoglobus fulgidus ModA, of which a crystal structure is known. We have measured A. fulgidus ModA with tungstate at the W L{sub 3} (2p{sub 3/2}) edge, and compared the results with the refined crystal structure. XAS studies of anion binding are feasible even if only weak interactions are present, are biologically relevant, and give new insights in the spectroscopy.

  12. Anion binding in biological systems

    Science.gov (United States)

    Feiters, Martin C.; Meyer-Klaucke, Wolfram; Kostenko, Alexander V.; Soldatov, Alexander V.; Leblanc, Catherine; Michel, Gurvan; Potin, Philippe; Küpper, Frithjof C.; Hollenstein, Kaspar; Locher, Kaspar P.; Bevers, Loes E.; Hagedoorn, Peter-Leon; Hagen, Wilfred R.

    2009-11-01

    We compare aspects of biological X-ray absorption spectroscopy (XAS) studies of cations and anions, and report on some examples of anion binding in biological systems. Brown algae such as Laminaria digitata (oarweed) are effective accumulators of I from seawater, with tissue concentrations exceeding 50 mM, and the vanadate-containing enzyme haloperoxidase is implicated in halide accumulation. We have studied the chemical state of iodine and its biological role in Laminaria at the I K edge, and bromoperoxidase from Ascophyllum nodosum (knotted wrack) at the Br K edge. Mo is essential for many forms of life; W only for certain archaea, such as Archaeoglobus fulgidus and the hyperthermophilic archaeon Pyrococcus furiosus, and some bacteria. The metals are bound and transported as their oxo-anions, molybdate and tungstate, which are similar in size. The transport protein WtpA from P. furiosus binds tungstate more strongly than molybdate, and is related in sequence to Archaeoglobus fulgidus ModA, of which a crystal structure is known. We have measured A. fulgidus ModA with tungstate at the W L3 (2p3/2) edge, and compared the results with the refined crystal structure. XAS studies of anion binding are feasible even if only weak interactions are present, are biologically relevant, and give new insights in the spectroscopy.

  13. NCBI nr-aa BLAST: CBRC-PABE-05-0000 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PABE-05-0000 sp|Q9H2B4|S26A1_HUMAN Sulfate anion transporter 1 (SAT -1) (Solute carrier fami ... gb|AAG22075.1|AF297659_1 sulfate/anion transporter SAT -1 protein [Homo sapiens] Q9H2B4 0.0 95% ...

  14. NCBI nr-aa BLAST: CBRC-CFAM-03-0030 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-CFAM-03-0030 sp|Q9H2B4|S26A1_HUMAN Sulfate anion transporter 1 (SAT -1) (Solute carrier fami ... gb|AAG22075.1|AF297659_1 sulfate/anion transporter SAT -1 protein [Homo sapiens] Q9H2B4 0.0 80% ...

  15. NCBI nr-aa BLAST: CBRC-BTAU-01-3012 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-BTAU-01-3012 sp|Q9H2B4|S26A1_HUMAN Sulfate anion transporter 1 (SAT -1) (Solute carrier fami ... gb|AAG22075.1|AF297659_1 sulfate/anion transporter SAT -1 protein [Homo sapiens] Q9H2B4 0.0 78% ...

  16. Anion exchange membrane

    Science.gov (United States)

    Verkade, John G; Wadhwa, Kuldeep; Kong, Xueqian; Schmidt-Rohr, Klaus

    2013-05-07

    An anion exchange membrane and fuel cell incorporating the anion exchange membrane are detailed in which proazaphosphatrane and azaphosphatrane cations are covalently bonded to a sulfonated fluoropolymer support along with anionic counterions. A positive charge is dispersed in the aforementioned cations which are buried in the support to reduce the cation-anion interactions and increase the mobility of hydroxide ions, for example, across the membrane. The anion exchange membrane has the ability to operate at high temperatures and in highly alkaline environments with high conductivity and low resistance.

  17. Training the next generation of Space and Earth Science Engineers and Scientists through student design and development of an Earth Observation Nanosatellite, AlbertaSat-1

    Science.gov (United States)

    Lange, B. A.; Bottoms, J.

    2011-12-01

    This presentation addresses the design and developmental process of a Nanosatellite by an interdisciplinary team of undergraduate and graduate students at the University of Alberta. The Satellite, AlbertaSat-1, is the University of Alberta's entry in the Canadian Satellite Design Challenge (CDSC); an initiative to entice Canadian students to contribute to space and earth observation technologies and research. The province of Alberta, while home to a few companies, is very limited in its space industry capacity. The University of Alberta reflects this fact, where one of the major unifying foci of the University is oil, the provinces greatest resource. For students at the U of A, this lack of focus on astronautical, aerospace and space/earth observational research limits their education in these industries/disciplines. A fully student operated project such as AlbertaSat-1 provides this integral experience to almost every discipline. The AlbertaSat-1 team is comprised of students from engineering, physics, chemistry, earth and atmospheric science, business, and computer science. While diverse in discipline, the team is also diverse in experience, spanning all levels from 1st year undergraduate to experienced PhD. Many skill sets are required and the diverse group sees that this is covered and all opinions voiced. Through immersion in the project, students learn quickly and efficiently. The necessity for a flawless product ensures that only the highest quality of work is presented. Students participating must research and understand their own subsystem as well as all others. This overall system view provides the best educational tool, as students are able to see the real impacts of their work on other subsystems. As the project is completely student organized, the participants gain not only technical engineering, space and earth observational education, but experience in operations and financial management. The direct exposure to all aspects of the space and earth

  18. Anions in Cometary Comae

    Science.gov (United States)

    Charnley, Steven B.

    2011-01-01

    The presence of negative ions (anions) in cometary comae is known from Giotto mass spectrometry of IP/Halley. The anions 0-, OH-, C-, CH- and CN- have been detected, as well as unidentified anions with masses 22-65 and 85-110 amu (Chaizy et al. 1991). Organic molecular anions are known to have a significant impact on the charge balance of interstellar clouds and circumstellar envelopes and have been shown to act as catalysts for the gas-phase synthesis of larger hydrocarbon molecules in the ISM, but their importance in cometary comae has not yet been explored. We present details of the first attempt to model the chemistry of anions in cometary comae. Based on the combined chemical and hydro dynamical model of Rodgers & Charnley (2002), we investigate the role of large carbon-chain anions in cometary coma chemistry. We calculate the effects of these anions on coma thermodynamics, charge balance and examine their impact on molecule formation.

  19. Unrecognized circulation of SAT 1 foot-and-mouth disease virus in cattle herds around Queen Elizabeth National Park in Uganda

    DEFF Research Database (Denmark)

    Dhikusooka, Moses Tefula; Ayebazibwe, Chrisostom; Namatovu, Alice;

    2016-01-01

    Foot-and-mouth disease (FMD) is endemic in Uganda in spite of the control measures used. Various aspects of the maintenance and circulation of FMD viruses (FMDV) in Uganda are not well understood; these include the role of the African buffalo (Syncerus caffer) as a reservoir for FMDV. To better...... understand the epidemiology of FMD at the livestock-wildlife-interface, samples were collected from young, unvaccinated cattle from 24 pastoral herds that closely interact with wildlife around Queen Elizabeth National Park in Uganda, and analysed for evidence of FMDV infection. In total, 37 (15 %) of 247...... serum samples had detectable antibodies against FMDV non-structural proteins (NSPs) using a pan-serotypic assay. Within these 37 sera, antibody titres ≥ 80 against the structural proteins of serotypes O, SAT 1, SAT 2 and SAT 3 were detected by ELISA in 5, 7, 4 and 3 samples, respectively, while...

  20. Anion Solvation in Carbonate Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhengcheng

    2015-11-16

    With the correlation between Li+ solvation and interphasial chemistry on anodes firmly established in Li-ion batteries, the effect of cation–solvent interaction has gone beyond bulk thermodynamic and transport properties and become an essential element that determines the reversibility of electrochemistry and kinetics of Li-ion intercalation chemistries. As of now, most studies are dedicated to the solvation of Li+, and the solvation of anions in carbonate-based electrolytes and its possible effect on the electrochemical stability of such electrolytes remains little understood. As a mirror effort to prior Li+ solvation studies, this work focuses on the interactions between carbonate-based solvents and two anions (hexafluorophosphate, PF6–, and tetrafluoroborate, BF4–) that are most frequently used in Li-ion batteries. The possible correlation between such interaction and the interphasial chemistry on cathode surface is also explored.

  1. Expression of organic anion-transporting polypeptides 1B3, 1B1, and 1A2 in human pancreatic cancer reveals a new class of potential therapeutic targets

    Directory of Open Access Journals (Sweden)

    Kounnis V

    2011-04-01

    Full Text Available Valentinos Kounnis1, Elli Ioachim2, Martin Svoboda3, Andreas Tzakos4, Ioannis Sainis1, Theresia Thalhammer3, Georg Steiner5, Evangelos Briasoulis11Cancer Biobank Center of the University of Ioannina, Greece; 2Pathology Department of Hatzikosta General Hospital, Ioannina Greece; 3Department of Pathophysiology and Allergy Research, Medical University of Vienna, Austria; 4Department of Chemistry, University of Ioannina, Greece; 5TissueGnostics GmbH, Vienna, AustriaBackground: Organic anion-transporting polypeptides (OATPs are influx transporters that mediate intracellular uptake of selective endogenous and xenobiotic compounds. Identification of new molecular targets and discovery of novel targeted therapies is top priority for pancreatic cancer, which lacks any effective therapy.Materials and methods: We studied expression of OATP 1A2, 1B1, and 1B3 in pancreatic cancer tissue and in cell lines. Formalin-fixed paraffin-embedded biopsy material of 12 human pancreatic cancers was immunohistochemically assessed for protein expression of the three studied influx transporters. Immunohistochemistry was evaluated by experienced pathologists and quantified by use of an automated image analysis system. BxPC-3 and MIA PaCa-2 pancreatic cancer cell lines were used to quantify transcripts of OATP 1B1 and 1B3.Results: OATP 1A2, 1B1, and 1B3 proteins were found ubiquitously expressed in all studied cases. Quantification performed by HistoQuest system revealed that mean intensity was 53 for 1A2, 45 for 1B1, and 167 for OATP 1B1/1B3 on a range scale 0–250 units. At mRNA level, 1B1 and 1B3 were overexpressed in both studied cancer cell lines but not in normal pancreatic tissue.Conclusion: OATPs 1A2, 1B1, and 1B3 are highly expressed in pancreatic adenocarcinoma. We suggest that expression of these transporters in pancreatic cancer justify research efforts towards discovery of novel therapeutics targeting OATPs.Keywords: organic anion-transporting polypeptides

  2. Modification of the charge transport properties of the copper phthalocyanine/poly(vinyl alcohol) interface using cationic or anionic surfactant for field-effect transistor performance enhancement

    Science.gov (United States)

    Jastrombek, Diana; Nawaz, Ali; Koehler, Marlus; Meruvia, Michelle S.; Hümmelgen, Ivo A.

    2015-08-01

    We report on the performance enhancement of organic field-effect transistors prepared using cross-linked poly(vinyl alcohol) as gate dielectric and copper phthalocyanine as channel semiconductor through gate dielectric surface treatment. The gate dielectric surface was treated using either a cationic surfactant, hexadecyltrimethylammonium bromide (CTAB), or an anionic surfactant, sodium dodecyl sulfate (SDS). We determined the charge-carrier field-effect mobility ( μ FET) in these transistors as a function of the effective channel thickness in the channel bottleneck, near to the transistor source. When compared to the untreated devices, in the devices treated with CTAB or SDS, the channel formation occurs at lower gate voltage and the carrier mobility in the thinnest channel region, corresponding to the immediate vicinity of the insulator/semiconductor interface, is significantly higher. The surfactant treatment leads to a tenfold increase in μ FET and significant enhancement in capacitance, on/off current ratio and transconductance of the transistor.

  3. Modification of the charge transport properties of the copper phthalocyanine/poly(vinyl alcohol) interface using cationic or anionic surfactant for field-effect transistor performance enhancement

    International Nuclear Information System (INIS)

    We report on the performance enhancement of organic field-effect transistors prepared using cross-linked poly(vinyl alcohol) as gate dielectric and copper phthalocyanine as channel semiconductor through gate dielectric surface treatment. The gate dielectric surface was treated using either a cationic surfactant, hexadecyltrimethylammonium bromide (CTAB), or an anionic surfactant, sodium dodecyl sulfate (SDS). We determined the charge-carrier field-effect mobility ( μ FET) in these transistors as a function of the effective channel thickness in the channel bottleneck, near to the transistor source. When compared to the untreated devices, in the devices treated with CTAB or SDS, the channel formation occurs at lower gate voltage and the carrier mobility in the thinnest channel region, corresponding to the immediate vicinity of the insulator/semiconductor interface, is significantly higher. The surfactant treatment leads to a tenfold increase in μ FET and significant enhancement in capacitance, on/off current ratio and transconductance of the transistor. (paper)

  4. Functional interaction of the cystic fibrosis transmembrane conductance regulator with members of the SLC26 family of anion transporters (SLC26A8 and SLC26A9): physiological and pathophysiological relevance.

    Science.gov (United States)

    El Khouri, Elma; Touré, Aminata

    2014-07-01

    The solute carrier 26 (SLC26) proteins are transmembrane proteins located at the plasma membrane of the cells and transporting a variety of monovalent and divalent anions, including chloride, bicarbonate, sulfate and oxalate. In humans, 11 members have been identified (SLC26A1 to SLC26A11) and although part of them display a very restricted tissue expression pattern, altogether they are widely expressed in the epithelial cells of the body where they contribute to the composition and the pH regulation of the secreted fluids. Importantly, mutations in SLC26A2, A3, A4, and A5 have been associated with distinct human genetic recessive disorders (i.e. diastrophic dysplasia, congenital chloride diarrhea, Pendred syndrome and deafness, respectively), demonstrating their essential and non-redundant functions in many tissues. During the last decade, physical and functional interactions of SLC26 members with the cystic fibrosis transmembrane conductance regulator (CFTR) have been highly documented, leading to the model of a crosstalk based on the binding of the SLC26 STAS domain to the CFTR regulatory domain. In this review, we will focus on the functional interaction of SLC26A8 and SLC26A9 with the CFTR channel. In particular we will highlight the newly published studies indicating that mutations in SLC26A8 and SLC26A9 proteins are associated with a deregulation of the CFTR anion transport activity in the pathophysiological context of the sperm and the pulmonary cells. These studies confirm the physiological relevance of SLC26 and CFTR cross-regulation, opening new gates for the treatment of cystic fibrosis. PMID:24530837

  5. Intrinsic anion oxidation potentials.

    Science.gov (United States)

    Johansson, Patrik

    2006-11-01

    Anions of lithium battery salts have been investigated by electronic structure calculations with the objective to find a computational measure to correlate with the observed (in)stability of nonaqueous lithium battery electrolytes vs oxidation often encountered in practice. Accurate prediction of intrinsic anion oxidation potentials is here made possible by computing the vertical free energy difference between anion and neutral radical (Delta Gv) and further strengthened by an empirical correction using only the anion volume as a parameter. The 6-311+G(2df,p) basis set, the VSXC functional, and the C-PCM SCRF algorithm were used. The Delta Gv calculations can be performed using any standard computational chemistry software. PMID:17078600

  6. Anion-π catalysis.

    Science.gov (United States)

    Zhao, Yingjie; Beuchat, César; Domoto, Yuya; Gajewy, Jadwiga; Wilson, Adam; Mareda, Jiri; Sakai, Naomi; Matile, Stefan

    2014-02-01

    The introduction of new noncovalent interactions to build functional systems is of fundamental importance. We here report experimental and theoretical evidence that anion-π interactions can contribute to catalysis. The Kemp elimination is used as a classical tool to discover conceptually innovative catalysts for reactions with anionic transition states. For anion-π catalysis, a carboxylate base and a solubilizer are covalently attached to the π-acidic surface of naphthalenediimides. On these π-acidic surfaces, transition-state stabilizations up to ΔΔGTS = 31.8 ± 0.4 kJ mol(-1) are found. This value corresponds to a transition-state recognition of KTS = 2.7 ± 0.5 μM and a catalytic proficiency of 3.8 × 10(5) M(-1). Significantly increasing transition-state stabilization with increasing π-acidity of the catalyst, observed for two separate series, demonstrates the existence of "anion-π catalysis." In sharp contrast, increasing π-acidity of the best naphthalenediimide catalysts does not influence the more than 12 000-times weaker substrate recognition (KM = 34.5 ± 1.6 μM). Together with the disappearance of Michaelis-Menten kinetics on the expanded π-surfaces of perylenediimides, this finding supports that contributions from π-π interactions are not very important for anion-π catalysis. The linker between the π-acidic surface and the carboxylate base strongly influences activity. Insufficient length and flexibility cause incompatibility with saturation kinetics. Moreover, preorganizing linkers do not improve catalysis much, suggesting that the ideal positioning of the carboxylate base on the π-acidic surface is achieved by intramolecular anion-π interactions rather than by an optimized structure of the linker. Computational simulations are in excellent agreement with experimental results. They confirm, inter alia, that the stabilization of the anionic transition states (but not the neutral ground states) increases with the π-acidity of the

  7. Frequencies of two functionally significant SNPs and their haplotypes of organic anion transporting polypeptide 1B1 SLCO1B1 gene in six ethnic groups of Pakistani population

    Directory of Open Access Journals (Sweden)

    Tausif Ahmed Rajput

    2014-06-01

    Full Text Available Objective(s:Organic anion transporter polypeptide 1B1 (OATP1B1 encoded by solute carrier organic transporter 1B1 (SLCO1B1 gene; a transporter involved in the uptake of drugs and endogenous compounds is present in hepatocyte sinusoidal membrane. Aim of this study was to investigate the frequencies of functionally significant SNPs (388A>G and 521T>C and their haplotypes in 6 ethnic groups of Pakistani population through the development of rapid and efficient Tetra amplification refractory mutation system (T. ARMS genotyping assay. Materials and Methods: Frequencies of alleles, genotype, and haplotypes of two functionally significant Single nucleotide polymorphism in 180 healthy Pakistani subjects and distributions in six ethnic groups by using a single step T. ARMS genotyping assay. Results: The allelic frequency for 388A>G SNP was 50% in total Pakistani population with distributions of 9.7%, 15.1%, 19.4%, 16.1%, 18.3%, and 21.5% in Punjabi, Sindhi, Balouchi, Pathan, Kashmiri and Hazara/Baltistan groups respectively; and for 521T>C SNP it was 23.9% in total Pakistani population with distributions of 11.1%, 8.9%, 15.6%, 11.1%, 31.1% and 22.2% in Punjabi, Sindhi, Balouchi, Pathan, Kashmiri, and Hazara/Baltistan groups. Both functionally significant SNPs occurred in four major haplotypes with a frequency of 35.5% for 388A/521T (*1A, 40.5% for 388G/521T (*1B, 14.4% for 388A/521C (*5, and 9.4% for 388G/521C (*15 with varying distributions among six ethnic groups. Conclusion: The 388A>G and 521T>C genotypes and corresponding haplotypes are present at varying frequencies in various ethnic groups of Pakistani population. Pharmacokinetic and pharmacodynamic

  8. Vanadogermanate cluster anions.

    Science.gov (United States)

    Whitfield, T; Wang, X; Jacobson, A J

    2003-06-16

    Three novel vanadogermanate cluster anions have been synthesized by hydrothermal reactions. The cluster anions are derived from the (V(18)O(42)) Keggin cluster shell by substitution of V=O(2+) "caps" by Ge(2)O(OH)(2)(4+) species. In Cs(8)[Ge(4)V(16)O(42)(OH)(4)].4.7H(2)O, 1, (monoclinic, space group C2/c (No. 15), Z = 8, a = 44.513(2) A, b = 12.7632(7) A, c = 22.923(1) A, beta = 101.376(1) degrees ) and (pipH(2))(4)(pipH)(4)[Ge(8)V(14)O(50).(H(2)O)] (pip = C(4)N(2)H(10)), 2 (tetragonal, space group P4(2)/nnm (No. 134), Z = 2, a = 14.9950(7) A, c = 18.408(1) A), two and four VO(2+) caps are replaced, respectively, and each cluster anion encapsulates a water molecule. In K(5)H(8)Ge(8)V(12)SO(52).10H(2)O, 3, (tetragonal, space group I4/m (No. 87), Z = 2, a = 15.573(1) A, c = 10.963(1) A), four VO(2+) caps are replaced by Ge(2)O(OH)(2)(4+) species, and an additional two are omitted. The cluster ion in 3 contains a sulfate anion disordered over two positions. The cluster anions are analogous to the vanadoarsenate anions [V(18)(-)(n)()As(2)(n)()O(42)(X)](m)(-) (X = SO(3), SO(4), Cl; n = 3, 4) previously reported. PMID:12793808

  9. Ocean wind and roughness retrieval with spaceborne GNSS-Reflectometry: first results from the UK TechDemoSat-1 mission

    Science.gov (United States)

    Gommenginger, C.; Foti, G.

    2015-12-01

    GNSS-Reflectometry (GNSS-R) is a ground breaking ocean remote sensing technique that exploits reflected signals from Global Navigation Satellite Systems (GNSS) to retrieve geophysical information about the ocean surface such as near-surface winds above the ocean. Adopting a bistatic radar configuration, signals emitted by GNSS satellites flying in Medium Earth Orbit (MEO) are received by a GNSS-R receiver on a Low Earth Orbit (LEO) observatory utilizing both a zenith antenna to receive the direct signal from the GNSS and a nadir antenna to acquire the earth-reflected signal. The reflected signal originated from a glistening zone on the ocean surface sited around the Specular Point (SP), the geometrical point on the Earth surface where GNSS signals are forward scattered in the specular direction. The two signals are correlated for different shifts in time (delay) and frequency (Doppler) relative to the specular point (SP) to produce a so-called Delay Doppler Map (DDM) of forward-scattered electromagnetic power over the surface. This paper gives an overview of recent results obtained for wind speed and ocean roughness retrieval with the Low-Earth-Orbiting UK TechDemoSat-1 satellite (TDS-1). Launched in July 2014, TDS-1 provides the first new spaceborne Global Navigation Satellite System-Reflectometry (GNSS-R) data since the pioneering UK-Disaster Monitoring Mission experiment in 2003. We present examples of onboard-processed delay Doppler Maps, including excellent DDM data quality for winds up to 27.9 m/s. The relationship between observed GNSS-R signals, wind speed and ocean roughness is explored using global collocated matchup datasets with METOP ASCAT scatterometer winds and WaveWatch3 numerical wave model output. Several Geophysical Model Functions are proposed, that make it possible to retrieve wind speed without bias and with a precision of the order of 2 m/s even without calibration. This work demonstrates the capabilities of low-cost, low-mass, low-power GNSS

  10. Anion Ordering in Bichalcogenides

    Directory of Open Access Journals (Sweden)

    Martin Valldor

    2016-07-01

    Full Text Available This review contains recent developments and new insights in the research on inorganic, crystalline compounds with two different chalcogenide ions (bichalcogenides. Anion ordering is used as a parameter to form structural dimensionalities as well as local- and global-electric polarities. The reason for the electric polarity is that, in the heterogeneous bichalcogenide lattice, the individual bond-lengths between cations and anions are different from those in a homogeneous anion lattice. It is also shown that heteroleptic tetrahedral and octahedral coordinations offer a multitude of new crystal fields and coordinations for involved cations. This coordination diversity in bichalcogenides seems to be one way to surpass electro-chemical redox potentials: three oxidation states of a single transition metal can be stabilized, e.g., Ba15V12S34O3. A new type of disproportionation, related to coordination, is presented and results from chemical pressure on the bichalcogenide lattices of (La,CeCrS2O, transforming doubly [CrS3/3S2/2O1/1]3− (5+1 into singly [CrS4/2S2/3]7/3− (6+0 and [CrS4/3O2/1]11/3− (4+2 coordinations. Also, magnetic anisotropy is imposed by the anion ordering in BaCoSO, where magnetic interactions via S or O occur along two different crystallographic directions. Further, the potential of the anion lattice is discussed as a parameter for future materials design.

  11. Whole-body distribution and radiation dosimetry of [11C]telmisartan as a biomarker for hepatic organic anion transporting polypeptide (OATP) 1B3

    International Nuclear Information System (INIS)

    Introduction: Telmisartan, a nonpeptide angiotensin II AT1 receptor antagonist used as an antihypertensive drug, is specifically taken up by the liver through the OATP1B3. PET imaging with [11C]telmisartan is expected to provide information about the whole body pharmacokinetics of telmisartan as well as its transport property by OATP1B3. The purpose of the study was to determine the biodistribution and radiation dosimetry of [11C]telmisartan in humans. Methods: Biodistribution of [11C]telmisartan was measured in three rats and six healthy male human volunteers. In the rat study, a dynamic emission scan was performed for 90 min. In the human study, dynamic whole-body PET images were acquired after intravenous injection of [11C]telmisartan. ROIs were defined for source organs on the PET images to measure time-course of [11C]telmisartan uptake as percentage injected dose and the number of disintegration for each organ. Radiation dosimetry was calculated with OLINDA/EXM. Results: In the rat study, most radioactivity was rapidly taken up by the liver and part of it was excreted into the biliary tract and intestine. Extrapolating from the rat data, the effective dose for the adult human being was estimated to be 3.65±0.01 microSv/MBq (n=3). In the human study, most of the tracer was taken up by the liver as well, although not as rapidly as in the rat. The activity in the gall bladder and intestine increased gradually. The effective dose for the adult human being was 4.24±0.09 microSv/MBq (n=6). Conclusions: [11C]Telmisartan is a safe PET tracer with a dosimetry profile comparable to other common 11C PET tracers.

  12. Migration of Cations and Anions in Amorphous Polymer Electrolytes

    Institute of Scientific and Technical Information of China (English)

    N.A.Stolwijk; S.H.Obeidi; M.Wiencierz

    2007-01-01

    1 Results Polymer electrolytes are used as ion conductors in batteries and fuel cells.Simple systems consist of a polymer matrix complexing an inorganic salt and are fully amorphous at the temperatures of interest.Both cations and anions are mobile and contribute to charge transport.Most studies on polymer electrolytes use the electrical conductivity to characterize the ion mobility.However,conductivity measurements cannot discriminate between cations and anions.This paper reports some recent results fr...

  13. Modeling Donnan Dialysis Separation for Carboxylic Anion Recovery

    DEFF Research Database (Denmark)

    Prado Rubio, Oscar Andres; Møllerhøj, Martin; Jørgensen, Sten Bay;

    2010-01-01

    dynamic model for transport of multiple ions through an anion exchange membrane is derived based on an irreversible thermodynamics approach. This model accounts for the convective transport of the dissociated and undissociated species in the channels with diffusion and migration across the bounda...

  14. Resonant spectra of quadrupolar anions

    CERN Document Server

    Fossez, K; Nazarewicz, W; Michel, N; Garrett, W R; Płoszajczak, M

    2016-01-01

    In quadrupole-bound anions, an extra electron is attached at a sufficiently large quadrupole moment of a neutral molecule, which is lacking a permanent dipole moment. The nature of the bound states and low-lying resonances of such anions is of interest for understanding the threshold behavior of open quantum systems in general. In this work, we investigate the properties of quadrupolar anions as extreme halo systems, the formation of rotational bands, and the transition from a subcritical to supercritical electric quadrupole moment. We solve the electron-plus-molecule problem using a non-adiabatic coupled-channel formalism by employing the Berggren ensemble, which explicitly contains bound states, narrow resonances, and the scattering continuum. We demonstrate that binding energies and radii of quadrupolar anions strictly follow the scaling laws for two-body halo systems. Contrary to the case of dipolar anions, ground-state band of quadrupolar anions smoothly extend into the continuum, and many rotational ban...

  15. Bound anionic states of adenine

    OpenAIRE

    Harańczyk, Maciej; Gutowski, Maciej; Li, Xiang; Bowen, Kit H.

    2007-01-01

    Anionic states of nucleic acid bases are involved in DNA damage by low-energy electrons and in charge transfer through DNA. Previous gas phase studies of free, unsolvated nucleic acid base parent anions probed only dipole-bound states, which are not present in condensed phase environments, but did not observe valence anionic states, which for purine bases are thought to be adiabatically unbound. Contrary to this expectation, we have demonstrated that some thus far ignored tautomers of adenine...

  16. Transport

    International Nuclear Information System (INIS)

    Transport is one of the major causes of environmental damage in Austria. Energy consumption, pollutants emissions, noise emissions, use of surfaces, sealing of surfaces, dissection of ecosystems and impact on landscape are the most significant environmental impacts caused by it. An overview of the transport development of passengers and freight in Austria is presented. Especially the energy consumption growth, carbon dioxide and nitrogen oxide emissions by type of transport, and the emissions development (HC, particle and carbon monoxide) of goods and passengers transport are analyzed covering the years 1980 - 1999. The health cost resulting from transport-related air pollution in Austria is given and measures to be taken for an effective control of the transport sector are mentioned. Figs. 8, Table 1. (nevyjel)

  17. Chemical Modeling of Cometary Anions

    Science.gov (United States)

    Cordiner, Martin; Charnley, S. B.

    2009-09-01

    The presence of negative ions (anions) in cometary comae is known from Giotto mass spectrometry of 1P/Halley. The anions O-, OH-, C-, CH- and CN- have been detected, as well as unidentified anions with masses 22-65 and 85-110 amu (Chaizy et al. 1991). Organic molecular anions are known to have a significant impact on the charge balance of interstellar clouds and circumstellar envelopes and have been shown to act as catalysts for the gas-phase synthesis of larger hydrocarbon molecules in the ISM, but their importance in cometary comae has not previously been explored. We present details of the first attempt to model the chemistry of anions in cometary comae. Based on the combined chemical and hydrodynamical model of Rodgers & Charnley (2002), we investigate the role of the hydrocarbon and nitrile anions Cn-, CnH- and CnN- in the coma. We calculate the effects of these anions on the charge balance and examine their impact on cometary coma chemistry. References: Chaizy, P. et al. 1991, Nature, 349, 393 Rodgers, S.D. & Charnley, S.B. 2002, MNRAS, 330, 660

  18. Phosphazene-promoted anionic polymerization

    KAUST Repository

    Zhao, Junpeng

    2014-01-01

    In the recent surge of metal-free polymerization techniques, phosphazene bases have shown their remarkable potential as organic promoters/catalysts for the anionic polymerization of various types of monomers. By complexation with the counterion (e.g. proton or lithium cation), phosphazene base significantly improve the nucleophilicity of the initiator/chain-end resulting in rapid and usually controlled anionic/quasi-anionic polymerization. In this review, we will introduce the general mechanism, i.e. in situ activation (of initiating sites) and polymerization, and summarize the applications of such a mechanism on macromolecular engineering toward functionalized polymers, block copolymers and complex macromolecular architectures.

  19. Grain boundary mobility in anion doped MgO

    Science.gov (United States)

    Kapadia, C. M.; Leipold, M. H.

    1973-01-01

    Certain anions OH(-), F(-) and Gl(-) are shown to enhance grain growth in MgO. The magnitude of their effect decreases in the order in which the anions are listed and depends on their location (solid-solution, second phase) in the MgO lattice. As most anions exhibit relatively high vapor pressures at sintering temperatures, they retard densification and invariably promote residual porosity. The role of anions on grain growth rates was studied in relation to their effect on pore mobility and pore removal; the atomic process controlling the actual rates was determined from observed kinetics in conjunction with the microstructural features. With respect to controlling mechanisms, the effects of all anions are not the same. OH(-) and F(-) control behavior through creation of a defect structure and a grain boundary liquid phase while Cl(-) promotes matter transport within pores by evaporation-condensation. Studies on an additional anion, S to the minus 2nd power gave results which were no different from undoped MgO, possibly because of evaporative losses during hot pressing. Hence, the effect of sulphur is negligible or undetermined.

  20. The many ways of making anionic clays

    Indian Academy of Sciences (India)

    Michael Rajamathi; Grace S Thomas; P Vishnu Kamath

    2001-10-01

    Together with hydrotalcite-like layered double hydroxides, bivalent and trivalent metal hydroxides and their hydroxy salts are actually anionic clays consisting of positively charged hydroxide layers with anions intercalated in the interlayer region. The anionic clays exhibit anion sorption, anion diffusion and exchange properties together with surface basicity making them materials of importance for many modern applications. In this article, we discuss many different ways of making anionic clays and compare and contrast the rich diversity of this class of materials with the better-known cationic clays.

  1. Aquaporins with anion/monocarboxylate permeability: mechanisms, relevance for pathogen-host interactions

    Directory of Open Access Journals (Sweden)

    Janis eRambow

    2014-09-01

    Full Text Available Classically, aquaporins are divided based on pore selectivity into water specific, orthodox aquaporins and solute-facilitating aquaglyceroporins, which conduct e.g. glycerol and urea. However, more aquaporin-passing substrates have been identified over the years, such as the gases ammonia and carbon dioxide or the water-related hydrogen peroxide, and it became apparent that not all aquaporins clearly fit into one of only two subfamilies. Furthermore, certain aquaporins from both major subfamilies have been reported to conduct inorganic anions, such as chloride, or monoacids/monocarboxylates, such as lactic acid/lactate. Here, we summarize the findings on aquaporin anion transport, analyze the pore layout of such aquaporins in comparison to prototypical non-selective anion channels, monocarboxylate transporters, and formate-nitrite transporters, and discuss in which scenarios anion conducting aquaporins may be of physiological relevance.

  2. IMPROVING OF ANION EXCHANGERES REGENERATION

    Directory of Open Access Journals (Sweden)

    Muzher M. Ibrahim

    2013-05-01

    Full Text Available Inthis study, Different basis [NaOH and KOH] of variable concentration are usedto reactivate Anion exchangers employing different schemes .The Laboratoryresults showed large improvement in efficiency of these exchangers ( i.eoperating time was increased from 12 to 42 hours .The results of this work showed that the environmentalload (waste water can be reduced greatly when using the proposed regenerationscheme .

  3. Efficient Amide Based Halogenide Anion Receptors

    Institute of Scientific and Technical Information of China (English)

    Hong Xing WU; Feng Hua LI; Hai LIN; Shou Rong ZHU; Hua Kuan LIN

    2005-01-01

    In this paper, we present the synthesis and anion recognition properties of the amide based phenanthroline derivatives 1, 2 and 3. In all cases 1:1 receptor: anion complexes were observed. The receptors were found to be selective for fluoride and chloride respectively over other putative anionic guest species.

  4. Alkaline Anion-Exchange Membranes Containing Mobile Ion Shuttles.

    Science.gov (United States)

    Ge, Xiaolin; He, Yubin; Guiver, Michael D; Wu, Liang; Ran, Jin; Yang, Zhengjin; Xu, Tongwen

    2016-05-01

    A new class of alkaline anion-exchange membranes containing mobile ion shuttles is developed. It is achieved by threading ionic linear guests into poly(crown ether) hosts via host-guest molecular interaction. The thermal- and pH-triggered shuttling of ionic linear guests remarkably increases the solvation-shell fluctuations in inactive hydrated hydroxide ion complexes (OH(-) (H2 O)4 ) and accelerates the OH(-) transport. PMID:26972938

  5. Laser Cooling of Molecular Anions

    CERN Document Server

    Yzombard, Pauline; Gerber, Sebastian; Doser, Michael; Comparat, Daniel

    2015-01-01

    We propose a scheme for laser cooling of negatively charged molecules. We briefly summarise the requirements for such laser cooling and we identify a number of potential candidates. A detailed computation study with C$\\_2^-$, the most studied molecular anion, is carried out. Simulations of 3D laser cooling in a gas phase show that this molecule could be cooled down to below 1 mK in only a few tens of milliseconds, using standard lasers. Sisyphus cooling, where no photo-detachment process is present, as well as Doppler laser cooling of trapped C$\\_2^-$, are also simulated. This cooling scheme has an impact on the study of cold molecules, molecular anions, charged particle sources and antimatter physics.

  6. Polymerization of anionic wormlike micelles.

    Science.gov (United States)

    Zhu, Zhiyuan; González, Yamaira I; Xu, Hangxun; Kaler, Eric W; Liu, Shiyong

    2006-01-31

    Polymerizable anionic wormlike micelles are obtained upon mixing the hydrotropic salt p-toluidine hydrochloride (PTHC) with the reactive anionic surfactant sodium 4-(8-methacryloyloxyoctyl)oxybenzene sulfonate (MOBS). Polymerization captures the cross-sectional radius of the micelles (approximately 2 nm), induces micellar growth, and leads to the formation of a stable single-phase dispersion of wormlike micellar polymers. The unpolymerized and polymerized micelles were characterized using static and dynamic laser light scattering, small-angle neutron scattering, 1H NMR, and stopped-flow light scattering. Stopped-flow light scattering was also used to measure the average lifetime of the unpolymerized wormlike micelles. A comparison of the average lifetime of unpolymerized wormlike micelles with the surfactant monomer propagation rate was used to elucidate the mechanism of polymerization. There is a significant correlation between the ratio of the average lifetime to the monomer propagation rate and the average aggregation number of the polymerized wormlike micelles. PMID:16430253

  7. Environmental behavior of inorganic anions

    International Nuclear Information System (INIS)

    Recent efforts have addressed two aspects of anion behavior in the soil/plant system. The first involves evaluation of the gaseous component of the terrestrial iodine cycle in soils and plants. Field analyses of 129I in soils and vegetation adjacent to a fuels reprocessing facility, which was idle for 10 years prior to the study, indicated that there may be a significant gaseous component to the terrestrial iodine cycle. Soil substrates, including a silt-sand, organic forest soil, quartz sand, and a sterilized soil, were amended with radioiodide, and the rates and quality of the volatile components evaluated

  8. Modelling and optimization of the ion exchange membrane bioreactor for removal of anionic pollutants from drinking water streams

    OpenAIRE

    Ricardo, Ana Rita da Fonseca

    2011-01-01

    The present work aimed at studying the treatment of drinking water supplies contaminated with perchlorate and nitrate, using the Ion Exchange Membrane Bioreactor (IEMB) concept. This system combines the transport of these two anions from contaminated water, through an anion exchange membrane, with their biological reduction in a separate compartment. In the IEMB, the mass transport is dependent not only from membrane properties but also from the biocompartment conditions. Multivariate stat...

  9. Electron transfer in dinucleoside phosphate anions

    International Nuclear Information System (INIS)

    The electron transfer reaction within various dinucleoside phosphate radical anions has been investigated by ESR spectroscopy and pulse radiolysis. In the ESR work electrons are produced by photolysis of K4Fe(CN)6 in a 12 M LiCl glass at 770K. Upon photobleaching the electrons react with the dinucleoside phosphate to form the anion radical. The anions of the four DNA nucleosides were also produced and their ESR spectra were appropriately weighted and summed by computer to simulate the spectra found for the dinucleoside phosphate anions. From the analysis the relative amounts of each of the nucleoside anions in the dinucleoside phosphate anion were determined. Evidence suggests the electron affinity of the pyrimidine bases are greater than the purine bases; however, the results are not sufficient to distinguish between the individual purine or pyrimidine. When dinucleoside phosphate anions containing thymidine are warmed, protonation occurs only on thymine to produce the well known ''thymyl'' spectrum. Pulse radiolysis experiments on individual nucleotides (TMP, dAMP), mixtures of these nucleotides and the dinucleoside phosphate, TdA, in aqueous solution at room temperature show that in the TdA anion electron transfer occurs from adenine to thymine, whereas no electron transfer is found for mixtures of individual nucleotides. Protonation is found to occur only on thymine in the TdA anion in agreement with the ESR results

  10. Absence of transepithelial anion exchange by rabbit OMCD: Evidence against reversal of cell polarity

    International Nuclear Information System (INIS)

    In the rabbit cortical collecting duct (CCD), Cl tracer crosses the epithelium predominantly via an anion exchange system that operates in either a Cl-Cl or Cl-HCO3 exchange mode. In the present study, the authors used the 36Cl lumen-to-bath rate coefficient (KCl, nm/s), a sensitive measurement of CCD transepithelial anion transport, to investigate the nature of Cl transport in the medullary collecting duct dissected from inner stripe, outer medulla (OMCD). The KCl in OMCD perfused and bathed in HCO3-Ringer solution was low and similar to that value observed in the CCD when anion exchange is inhibited and Cl permeates the epithelium by diffusion. To test the hypothesis that metabolic alkalosis could reverse the polarity of intercalated cells and thus induce an apical Cl-HCO3 exchanger in H+-secreting OMCD cells, they measured KCl in OMCD from rabbits make alkalotic by deoxycorticosterone and furosemide. Although the base-line KCl was slightly higher than in OMCD from control rabbits, the value was still far lower than the KCl under comparable conditions in CCD. They conclude (1) Cl transport across the MCD by anion exchange is immeasurably low or nonexistent; (2) unlike the CCD, Cl transport in OMCD is not responsive to cAMP; and (3) metabolic alkalosis does not induce an apical anion exchanger in OMCD, i.e., does not cause epithelial polarity reversal

  11. The STAS domain of mammalian SLC26A5 prestin harbours an anion-binding site.

    Science.gov (United States)

    Lolli, Graziano; Pasqualetto, Elisa; Costanzi, Elisa; Bonetto, Greta; Battistutta, Roberto

    2016-02-15

    Prestin is a unique ATP- and Ca(2+)-independent molecular motor with piezoelectric characteristics responsible for the electromotile properties of mammalian cochlear outer hair cells, i.e. the capacity of these cells to modify their length in response to electric stimuli. This 'electromotility' is at the basis of the exceptional sensitivity and frequency selectivity distinctive of mammals. Prestin belongs to the SLC26 (solute carrier 26) family of anion transporters and needs anions to function properly, particularly Cl(-). In the present study, using X-ray crystallography we reveal that the STAS (sulfate transporter and anti-sigma factor antagonist) domain of mammalian prestin, considered an 'incomplete' transporter, harbours an unanticipated anion-binding site. In parallel, we present the first crystal structure of a prestin STAS domain from a non-mammalian vertebrate prestin (chicken) that behaves as a 'full' transporter. Notably, in chicken STAS, the anion-binding site is lacking because of a local structural rearrangement, indicating that the presence of the STAS anion-binding site is exclusive to mammalian prestin. PMID:26635354

  12. Ionic Block Copolymers for Anion Exchange Membranes

    Science.gov (United States)

    Tsai, Tsung-Han; Herbst, Dan; Giffin, Guinevere A.; di Noto, Vito; Witten, Tom; Coughlin, E. Bryan

    2013-03-01

    Anion exchange membrane (AEM) fuel cells have regained interest because it allows the use of non-noble metal catalysts. Until now, most of the studies on AEM were based on random polyelectrolytes. In this work, Poly(vinylbenzyltrimethylammonium bromide)-b- (methylbutylene) ([PVBTMA][Br]-b-PMB) was studied by SAXS, TEM and dielectric spectroscopy to understand the fundamental structure-conductivity relationship of ion transport mechanisms within well-ordered block copolymers. The ionic conductivity and the formation of order structure were dependent on the casting solvent. Higher ion exchange capacity (IEC) of the membranes showed higher conductivity at as IEC values below 1.8mmol/g, as above this, the ionic conductivity decreases due to more water uptake leading to dilution of charge density. The humidity dependence of morphology exhibited the shifting of d-spacing to higher value and the alteration in higher characteristic peak of SAXS plot as the humidity increase from the dry to wet state. This phenomenon can be further explained by a newly developed polymer brush theory. Three ionic conduction pathways with different conduction mechanism within the membranes can be confirmed by broadband electric spectroscopy. US Army MURI (W911NF1010520)

  13. Ursodeoxycholic acid and superoxide anion

    Institute of Scientific and Technical Information of China (English)

    Predrag Ljubuncic; Omar Abu-Salach; Arieh Bomzon

    2005-01-01

    AIM: To investigate the ability of ursodeoxycholic acid (UDCA) to scavenge superoxide anion (O2-).METHODS: We assessed the ability of UDCA to scavenge (O2-) generated by xanthine-xanthine oxidase (X-XO) in a cell-free system and its effect on the rate of O2--induced ascorbic acid (AA) oxidation in hepatic post-mitochondrial supernatants.RESULTS: UDCA at a concentration as high as 1 mmol/Ldid not impair the ability of the X-XO system to generate O2-, but could scavenge O2- at concentrations of 0.5 and 1 mmol/L, and decrease the rate of AA oxidation at a concentration of 100 μmol/L.CONCLUSION: UDCA can scavenge O2-, an action that may be beneficial to patients with primary biliary cirrhosis.

  14. Tripodal Receptors for Cation and Anion Sensors

    Directory of Open Access Journals (Sweden)

    David N. Reinhoudt

    2006-08-01

    Full Text Available This review discusses different types of artificial tripodal receptors for the selectiverecognition and sensing of cations and anions. Examples on the relationship between structure andselectivity towards cations and anions are described. Furthermore, their applications as potentiometricion sensing are emphasised, along with their potential applications in optical sensors or optodes.

  15. Test procedure for anion exchange chromatography

    International Nuclear Information System (INIS)

    Plutonium from stored nitrate solutions will be sorbed onto anion exchange resins and converted to storable plutonium dioxide. Useful information will be simultaneously gained on the thermal stability and ion exchange capacity of four commercially available anion exchange resins over several years and under severe degradative conditions. This information will prove useful in predicting the safe and efficient lifetimes of these resins

  16. Simultaneous anion and cation mobility in polypyrrole

    DEFF Research Database (Denmark)

    Skaarup, Steen; Bay, Lasse; Vidanapathirana, K.;

    2003-01-01

    Polypyrrole (PPy) polymer films permanently doped with large, immobile anion dodecyl benzene sulfonate (DBS) have been characterized by cyclic voltammetry in order to clarify the roles of cations and anions in the aqueous electrolyte as mobile ions in the film. Aqueous solutions of 0.05-0.1 M alk...

  17. Counterintuitive interaction of anions with benzene derivatives

    Science.gov (United States)

    Quiñonero, David; Garau, Carolina; Frontera, Antonio; Ballester, Pau; Costa, Antonio; Deyà, Pere M.

    2002-06-01

    Ab initio calculations were carried out on complexes between 1,3,5-trinitrobenzene (TNB) and anions, where the anion is positioned over the ring along the C3 axis. This study combines crystallographic and computational evidences to demonstrate an attractive interaction between the anion and the π-cloud of TNB. This interaction is rationalized based on the important role of the quadrupole moment of TNB and the anion-induced polarization. In addition, this study has been extended to 1,3,5-trifluorobenzene (TFB), which possesses a very small quadrupole moment. As a result, minimum energy complexes have been found between TFB and both anions and cations due to the stabilization obtained from the ion-induced polarization.

  18. Biliary secretion of organic anions in the dog: association with defined lipid particles

    International Nuclear Information System (INIS)

    Organic anions have recently been found to partition in vitro into various biliary lipid particulate species according to their relative hydrophobicities. To establish the physiological relevance of these observations, we intravenously injected various radiolabeled organic anions and assessed the distributions of parent compounds and their metabolites to lipid particles in canine bile. Partitioning into various biliary lipid particles was determined by gel permeation chromatography. Relative hydrophobicities of the various organic anions and their radiolabeled conjugates were determined by reverse-phase high-pressure liquid chromatography. A strong positive correlation (P less than 0.001) was found between percent vesicular association and degree of hydrophobicity for a given organic anion and/or its more polar conjugate. We conclude that 1) the hydrophobic-hydrophilic balance of organic anions is a key factor governing their partitioning to lipid particles secreted in bile; 2) the present study agrees well with our previously published in vitro observations; and 3) other chemical constituents, e.g., proteins, mucin, etc., appear to have little or no effect on organic anion transport in bile

  19. Experimental evidence for the functional relevance of anion-π interactions

    Science.gov (United States)

    Dawson, Ryan E.; Hennig, Andreas; Weimann, Dominik P.; Emery, Daniel; Ravikumar, Velayutham; Montenegro, Javier; Takeuchi, Toshihide; Gabutti, Sandro; Mayor, Marcel; Mareda, Jiri; Schalley, Christoph A.; Matile, Stefan

    2010-07-01

    Attractive in theory and confirmed to exist, anion-π interactions have never really been seen at work. To catch them in action, we prepared a collection of monomeric, cyclic and rod-shaped naphthalenediimide transporters. Their ability to exert anion-π interactions was demonstrated by electrospray tandem mass spectrometry in combination with theoretical calculations. To relate this structural evidence to transport activity in bilayer membranes, affinity and selectivity sequences were recorded. π-acidification and active-site decrowding increased binding, transport and chloride > bromide > iodide selectivity, and supramolecular organization inverted acetate > nitrate to nitrate > acetate selectivity. We conclude that anion-π interactions on monomeric surfaces are ideal for chloride recognition, whereas their supramolecular enhancement by π,π-interactions appears perfect to target nitrate. Chloride transporters are relevant to treat channelopathies, and nitrate sensors to monitor cellular signaling and cardiovascular diseases. A big impact on organocatalysis can be expected from the stabilization of anionic transition states on chiral π-acidic surfaces.

  20. Perpendicularly Aligned, Anion Conducting Nanochannels in Block Copolymer Electrolyte Films

    Energy Technology Data Exchange (ETDEWEB)

    Arges, Christopher G.; Kambe, Yu; Suh, Hyo Seon; Ocola, Leonidas E.; Nealey, Paul F.

    2016-03-08

    Connecting structure and morphology to bulk transport properties, such as ionic conductivity, in nanostructured polymer electrolyte materials is a difficult proposition because of the challenge to precisely and accurately control order and the orientation of the ionic domains in such polymeric films. In this work, poly(styrene-block-2-vinylpyridine) (PSbP2VP) block copolymers were assembled perpendicularly to a substrate surface over large areas through chemical surface modification at the substrate and utilizing a versatile solvent vapor annealing (SVA) technique. After block copolymer assembly, a novel chemical vapor infiltration reaction (CVIR) technique selectively converted the 2-vinylpyridine block to 2-vinyl n-methylpyridinium (NMP+ X-) groups, which are anion charge carriers. The prepared block copolymer electrolytes maintained their orientation and ordered nanostructure upon the selective introduction of ion moieties into the P2VP block and post ion-exchange to other counterion forms (X- = chloride, hydroxide, etc.). The prepared block copolymer electrolyte films demonstrated high chloride ion conductivities, 45 mS cm(-1) at 20 degrees C in deionized water, the highest chloride ion conductivity for anion conducting polymer electrolyte films. Additionally, straight-line lamellae of block copolymer electrolytes were realized using chemoepitaxy and density multiplication. The devised scheme allowed for precise and accurate control of orientation of ionic domains in nanostructured polymer electrolyte films and enables a platform for future studies that examines the relationship between polymer electrolyte structure and ion transport.

  1. Efficiency of adsorption concentration of single-charged inorganic anions

    International Nuclear Information System (INIS)

    Results of adsorption concentration of inorganic anions Br-, I-, SCN- from diluted aqueous solutions using of N-alkylpyridinium chlorides (alkyl C13-C16) are presented. It is ascertained that interaction between extracted anion and surfactant cation, determining the efficiency of foam flotation of the anions investigated, increases with the decrease in anion hydration in the series Br-, I-, SCN-

  2. Novel pseudo-delocalized anions for lithium battery electrolytes.

    Science.gov (United States)

    Jónsson, Erlendur; Armand, Michel; Johansson, Patrik

    2012-05-01

    A novel anion concept of pseudo-delocalized anions, anions with distinct positive and negative charge regions, has been studied by a computer aided synthesis using DFT calculations. With the aim to find safer and better performing lithium salts for lithium battery electrolytes two factors have been evaluated: the cation-anion interaction strength via the dissociation reaction LiAn ⇌ Li(+) + An(-) and the anion oxidative stability via a vertical ionisation from anion to radical. Based on our computational results some of these anions have shown promise to perform well as lithium salts for modern lithium batteries and should be interesting synthetic targets for future research. PMID:22441354

  3. Studies of anions sorption on natural zeolites.

    Science.gov (United States)

    Barczyk, K; Mozgawa, W; Król, M

    2014-12-10

    This work presents results of FT-IR spectroscopic studies of anions-chromate, phosphate and arsenate - sorbed from aqueous solutions (different concentrations of anions) on zeolites. The sorption has been conducted on natural zeolites from different structural groups, i.e. chabazite, mordenite, ferrierite and clinoptilolite. The Na-forms of sorbents were exchanged with hexadecyltrimethylammonium cations (HDTMA(+)) and organo-zeolites were obtained. External cation exchange capacities (ECEC) of organo-zeolites were measured. Their values are 17mmol/100g for chabazite, 4mmol/100g for mordenite and ferrierite and 10mmol/100g for clinoptilolite. The used initial inputs of HDTMA correspond to 100% and 200% ECEC of the minerals. Organo-modificated sorbents were subsequently used for immobilization of mentioned anions. It was proven that aforementioned anions' sorption causes changes in IR spectra of the HDTMA-zeolites. These alterations are dependent on the kind of anions that were sorbed. In all cases, variations are due to bands corresponding to the characteristic Si-O(Si,Al) vibrations (occurring in alumino- and silicooxygen tetrahedra building spatial framework of zeolites). Alkylammonium surfactant vibrations have also been observed. Systematic changes in the spectra connected with the anion concentration in the initial solution have been revealed. The amounts of sorbed CrO4(2-), AsO4(3-) and PO4(3-) ions were calculated from the difference between their concentrations in solutions before (initial concentration) and after (equilibrium concentration) sorption experiments. Concentrations of anions were determined by spectrophotometric method. PMID:25002191

  4. Recognition of anions by protonated methylazacalixpyridines

    Institute of Scientific and Technical Information of China (English)

    Han-yuan GONG; De-xian WANG; Zhi-tang HUANG; Mei-xiang WANG

    2009-01-01

    Methylazacalixpyridines are a unique kind of macro-cyclic molecules that are able to self-regulate their conformations to best fit the guests. They had shown good recognition to both neutral molecules such as diols and fullerenes and cations. After protonation, the conformation of methylazacalixpyridines became more flexible and could serve as receptors for anions.In the solution, the protonated methylazacalix[2]pyri-dine[2]arene formed complexes with halides yield-ing biding constants of 79(mol/L)-1 for chloride,10 (mol/L)-1 for bromide, and 79 (mol/L)-1 for iodide,respectively. The crystal structures of the complexes between protonated methylazaealix[4]pyridine (MACP-4), methylazacalix[2]pyridine[2] arene (MACP-2-A-2), and iodide anion showed a multiple interaction mode including electrostatic attraction,hydrogen bonding, and anion-π interactions.

  5. Identification and characterization of anion binding sites in RNA

    Energy Technology Data Exchange (ETDEWEB)

    Kieft, Jeffrey S.; Chase, Elaine; Costantino, David A.; Golden, Barbara L. (Purdue); (Colorado)

    2010-05-24

    Although RNA molecules are highly negatively charged, anions have been observed bound to RNA in crystal structures. It has been proposed that anion binding sites found within isolated RNAs represent regions of the molecule that could be involved in intermolecular interactions, indicating potential contact points for negatively charged amino acids from proteins or phosphate groups from an RNA. Several types of anion binding sites have been cataloged based on available structures. However, currently there is no method for unambiguously assigning anions to crystallographic electron density, and this has precluded more detailed analysis of RNA-anion interaction motifs and their significance. We therefore soaked selenate into two different types of RNA crystals and used the anomalous signal from these anions to identify binding sites in these RNA molecules unambiguously. Examination of these sites and comparison with other suspected anion binding sites reveals features of anion binding motifs, and shows that selenate may be a useful tool for studying RNA-anion interactions.

  6. 菊苣对高尿酸血症鹌鹑肾脏有机阴离子转运体OAT3-LIKE的影响%Effect of Chinese Herb Chicory on Renal Organic Anion Transporter OAT3-LIKE of Hyperuricemia Quails

    Institute of Scientific and Technical Information of China (English)

    李丽玉; 林志健; 张冰; 王雪洁; 朱春胜; 牛红娟; 周月; 董百惠

    2015-01-01

    目的:从肾脏转运蛋白角度探究中药菊苣降尿酸的药效机制。方法将40只雄性迪法克鹌鹑按体质量随机分为5组,正常组给予普通饲料,其余各组均给予含酵母饲料(15 g·kg-1·d-1)建立高尿酸血症模型,同时给药组分别给予菊苣5,7.5 g·kg-1·d-1,苯溴马隆20 mg·kg-1·d-1,实验第35天处死。检测鹌鹑血清尿酸(Uric Acid,UA)、尿素氮(Urea Nitrogen,BUN)水平,并用Real-time RT-PCR(Real-time Reverse Transcription-Polymerase Chain Reaction)方法检测其肾脏有机阴离子转运体OAT3-LIKE(Organic Anion Transporter3-LIKE)的mRNA表达水平,同时测定肝脏尿酸代谢相关酶活性。结果与正常组比较,实验第21天、28天、35天模型组鹌鹑血尿酸升高,第35天肾脏OAT3-LIKE mRNA表达水平下降。与模型组比较,实验第35天,菊苣可以降低鹌鹑血尿酸水平,上调其肾脏OAT3-LIKE mRNA表达水平并降低肝脏腺苷脱氨酶(ADA)活性。结论高嘌呤食饵可以成功诱导鹌鹑高尿酸血症;菊苣具有抑制高尿酸血症鹌鹑尿酸生成和促进尿酸排泄的双重作用;菊苣药效机制可能与降低ADA活性及上调OAT3-LIKE表达水平相关。%Objective To explore the pharmacodynamic mechanism of chicory on lowering uric acid from the aspects of renal transport protein. Methods Forty male quails were randomly divided into five groups. The normal group was fed with common forage, and the other groups were fed with forage containing yeast(15 g·kg-1·d-1) to establish hyperuricemia model. At the same time,the medication groups were given chicory in the dosage of 5,7.5 g·kg-1·d-1, and benzbromarone 20 mg·kg-1·d-1, respectively. The quails were sacrificed on the 35th day. We detected serum uric acid(UA) and urea nitrogen levels and hepatic adenosine deaminase(ADA) activity, and examined the expression levels of renal organic anion transporter protein OAT3-LIKE mRNA using real

  7. Energy and structure of bonds in the interaction of organic anions with layered double hydroxide nanosheets: A molecular dynamics study

    Science.gov (United States)

    Tsukanov, A. A.; Psakhie, S. G.

    2016-01-01

    The application of hybrid and hierarchical nanomaterials based on layered hydroxides and oxyhydroxides of metals is a swiftly progressing field in biomedicine. Layered double hydroxides (LDH) possess a large specific surface area, significant surface electric charge and biocompatibility. Their physical and structural properties enable them to adsorb various kinds of anionic species and to transport them into cells. However, possible side effects resulting from the interaction of LDH with anions of the intercellular and intracellular medium need to be considered, since such interaction can potentially disrupt ion transport, signaling processes, apoptosis, nutrition and proliferation of living cells. In the present paper molecular dynamics is used to determine the energies of interaction of organic anions (aspartic acid, glutamic acid and bicarbonate) with a fragment of layered double hydroxide Mg/Al-LDH. The average number of hydrogen bonds between the anions and the hydroxide surface and characteristic binding configurations are determined. Possible effects of LDH on the cell resulting from binding of protein fragments and replacement of native intracellular anions with delivered anions are considered.

  8. Electron Photodetachment from Aqueous Anions. III. Dynamics of Geminate Pairs Derived from Photoexcitation of Mono- vs. Poly- atomic Anions

    CERN Document Server

    Lian, R; Crowell, R A; Shkrob, I A; Chen, X; Bradforth, S E; Lian, Rui; Oulianov, Dmitri A.; Crowell, Robert A.; Shkrob, Ilya A.; Bradforth, Stephen E.

    2005-01-01

    Photostimulated electron detachment from aqueous inorganic anions is the simplest example of solvent-mediated electron transfer. Here we contrast the behavior of halide anions with that of small polyatomic anions, such as pseudohalide anions (e.g., HS-) and common polyvalent anions (e.g., SO32-). Geminate recombination dynamics of hydrated electrons generated by 200 nm photoexcitation of aqueous anions (I-, Br-, OH-, HS-, CNS-, CO32-, SO32-, and Fe(CN)64-) have been studied. Prompt quantum yields for the formation of solvated, thermalized electrons and quantum yields for free electrons were determined. Pump-probe kinetics for 200 nm photoexcitation were compared with kinetics obtained at lower photoexcitation energy (225 nm or 242 nm) for the same anions, where possible. Free diffusion and mean force potential models of geminate recombination dynamics were used to analyze these kinetics. These analyses suggest that for polyatomic anions (including all polyvalent anions studied) the initial electron distributi...

  9. The assessment of pellicular anion-exchange resins for the determination of anions by ion chromatography

    International Nuclear Information System (INIS)

    Because pellicular anion-exchange resins suitable for the determination, by ion chromatography, of anions with alkaline eluents were unavailable in South Africa at the inception of this work, an attempt was made to prepare such resins. In this study it is shown that the pellicular resins produced are more efficient than the surface-aminated resins used previously. The simultaneous separation and determination of five common anions is demonstrated. The method was applied to the analysis of uranium leach liquors, effluent samples, and a solid sample of ferric oxide (goethite)

  10. Photoelectron spectroscopy and theoretical studies of anion-π interactions: binding strength and anion specificity.

    Science.gov (United States)

    Zhang, Jian; Zhou, Bin; Sun, Zhen-Rong; Wang, Xue-Bin

    2015-02-01

    Proposed in theory and then their existence confirmed, anion-π interactions have been recognized as new and important non-covalent binding forces. Despite extensive theoretical studies, numerous crystal structural identifications, and a plethora of solution phase investigations, anion-π interaction strengths that are free from complications of condensed-phase environments have not been directly measured in the gas phase. Herein we present a joint photoelectron spectroscopic and theoretical study on this subject, in which tetraoxacalix[2]arene[2]triazine 1, an electron-deficient and cavity self-tunable macrocyclic, was used as a charge-neutral molecular host to probe its interactions with a series of anions with distinctly different shapes and charge states (spherical halides Cl(-), Br(-), I(-), linear thiocyanate SCN(-), trigonal planar nitrate NO3(-), pyramidic iodate IO3(-), and tetrahedral sulfate SO4(2-)). The binding energies of the resultant gaseous 1 : 1 complexes (1·Cl(-), 1·Br(-), 1·I(-), 1·SCN(-), 1·NO3(-), 1·IO3(-) and 1·SO4(2-)) were directly measured experimentally, exhibiting substantial non-covalent interactions with pronounced anion-specific effects. The binding strengths of Cl(-), NO3(-), IO3(-) with 1 are found to be strongest among all singly charged anions, amounting to ca. 30 kcal mol(-1), but only about 40% of that between 1 and SO4(2-). Quantum chemical calculations reveal that all the anions reside in the center of the cavity of 1 with an anion-π binding motif in the complexes' optimized structures, where 1 is seen to be able to self-regulate its cavity structure to accommodate anions of different geometries and three-dimensional shapes. Electron density surface and charge distribution analyses further support anion-π binding formation. The calculated binding energies of the anions and 1 nicely reproduce the experimentally estimated electron binding energy increase. This work illustrates that size-selective photoelectron

  11. Donnan Membrane Technique (DMT) for Anion Measurement

    NARCIS (Netherlands)

    Alonso Vega, M.F.; Weng, L.P.; Temminghoff, E.J.M.; Riemsdijk, van W.H.

    2010-01-01

    Donnan membrane technique (DMT) is developed and tested for determination of free anion concentrations. Time needed to reach the Donnan membrane equilibrium depends on type of ions and the background. The Donnan membrane equilibrium is reached in 1 day for Cl-, 1-2 days for NO3-, 1-4 days for SO42-

  12. Gas-Phase Reactivity of Microsolvated Anions

    DEFF Research Database (Denmark)

    Thomsen, Ditte Linde

    intrinsic factors and solvent effects is the enhanced reactivity of α-nucleophiles – nucleophiles with a lone-pair adjacent to the attacking site – referred to as the α-effect. This thesis concerns the reactivity of microsolvated anions and in particular how the presence of a single solvent molecule affects...

  13. Comparison And Assessment for Major Anions

    Directory of Open Access Journals (Sweden)

    Mayada Mohammed

    2013-05-01

    Full Text Available Four major anions (nitrate, phosphate, sulfate and chloride  are measured in Tigris river at Mosul in six locations since Sept.2005 to June 2006.  The same 4 anions are measured previously by researches or thesis, so their results are added to the former one for comparison. The variation of flow is also reported for the whole period in order to study the concentration-flow relationship. The nitrate and phosphate concentrations are increasing with the river flow increase and decreasing with its decrease for most periods, (reaching up to1.05mg/l at June for nitrate and 0.482mg/l at April for phosphate .The lowest concentrations are observed (as low as 0.285 mg/l at Dec. for nitrate and 0.07mg/l at Jan for phosphate. Sulfate and chloride concentration are varying oppositely to the river flow for most periods, both showing their peaks at Jan. and their lowest at June (reaching up to 170 mg/l for sulfate, and 33.4 mg/l for chloride while the minimum values are 68mg/l for sulfate, and 15.6 mg/l for chloride. The data of the previous years are not complete and data for only 8 years are available. It indicates that the anions concentrations variation corresponding to the river flow is similar to that of  the studied years. However the data with equal flow rate only are used for comparison purposes to achieve correct results. All of the studied anions are increasing since 1982-2006 in different percentages except the phosphate. The 4 major anions are lower than the standards and MCL for the recent and previous studies.

  14. Understanding and modeling removal of anionic organic contaminants (AOCs) by anion exchange resins.

    Science.gov (United States)

    Zhang, Huichun; Shields, Anthony J; Jadbabaei, Nastaran; Nelson, Maurice; Pan, Bingjun; Suri, Rominder P S

    2014-07-01

    Ionic organic contaminants (OCs) are a growing concern for water treatment and the environment and are removed inefficiently by many existing technologies. This study examined removal of anionic OCs by anion exchange resins (AXRs) as a promising alternative. Results indicate that two polystyrene AXRs (IRA910 and IRA96) have higher sorption capacities and selectivity than a polyacrylate resin (A860). For the polystyrene resins, selectivity follows: phenolates ≥ aromatic dicarboxylates > aromatic monocarboxylates > benzenesulfonate > aliphatic carboxylates. This trend can be explained based on hydration energy, the number of exchange groups, and aromaticity and hydrophobicity of the nonpolar moiety (NPM) of the anions. For A860, selectivity only varies within a narrow range (0.13-1.64). Despite the importance of the NPM of the anions, neutral solutes were sorbed much less, indicating synergistic combinations of electrostatic and nonelectrostatic interactions in the overall sorption. By conducting multiple linear regression between Abraham's descriptors and nature log of selectivity, induced dipole-related interactions and electrostatic interactions were found to be the most important interaction forces for sorption of the anions, while solute H-bond basicity has a negative effect. A predictive model was then developed for carboxylates and phenolates based on the poly parameter linear free energy relationships established for a diverse range of 16 anions and 5 neutral solutes, and was validated by accurate prediction of sorption of five test solutes within a wide range of equilibrium concentrations and that of benzoate at different pH. PMID:24877792

  15. Electronic structure calculations of acetonitrile cluster anions: Stabilization mechanism of molecular radical anions by solvation

    International Nuclear Information System (INIS)

    Systematic electronic structure calculations have been performed for (CH3CN)n-(n=2-10) anion clusters with the hybrid B3LYP and non-hybrid PW91 density-functional methods in order to understand the stabilization mechanism of an acetonitrile dimer radical anion core by solvent molecules. Since the excess negative charge is mainly localized on N atoms in the dimer anion core, solvent acetonitrile molecules are bound to the N atoms by C-H...Nδ- hydrogen-bond-like attractive interaction with the binding energy per bond being about 10-13kcal/mol. Due to this stabilization mechanism, the anion cluster for n>=4-6 is stable with respect to the electron autodetachment. Geometry optimization was also carried out for the (CH3CN)6- anion cluster where an excess electron was internally trapped. The size dependence of the stabilization energy and vertical detachment energy for the (CH3CN)n- anion clusters is discussed

  16. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance

    International Nuclear Information System (INIS)

    The major thrust of this project, led by the University of Kansas (Prof. Kristin Bowman-James), entails an exploration of the basic determinants of anion recognition and their application to the design, synthesis, and testing of novel sulfate extractants. A key scientific inspiration for the work comes from the need, codified in simple-to-appreciate terms by the Oak Ridge National Laboratory component of the team (viz. Dr. Bruce Moyer), for chemical entities that can help in the extractive removal of species that have low solubilities in borosilicate glass. Among such species, sulfate anion, has been identified as particularly insidious. Its presence interferes with the vitrification process, thus rendering the remediation of tank waste from, e.g., the Hanford site far more difficult and expensive. The availability of effective extractants, that would allow for the separation of separating sulfate from the major competing anions in the waste, especially nitrate, could allow for pre-vitrification removal of sulfate via liquid-liquid extraction. The efforts at The University of Texas, the subject of this report, have thus concentrated on the development of new sulfate receptors. These systems are designed to increase our basic understanding of anion recognition events and set the stage for the development of viable sulfate anion extractants. In conjunction with the Oak Ridge National Laboratory (ORNL) members of the research team, several of these new receptors were studied as putative extractants, with two of the systems being shown to act as promising synergists for anion exchange.

  17. Reversible photochromism of an N-salicylidene aniline anion.

    Science.gov (United States)

    Jacquemin, Pierre-Loïc; Robeyns, Koen; Devillers, Michel; Garcia, Yann

    2014-01-21

    The first N-salicylidene aniline anion showing reversible solid state thermochromic and photochromic properties is described. The photo-isomerization involves a trans-keto form which is stabilized thanks to the local anion surrounding. This photochromic anion can be used as a guest for the preparation of hybrid materials by insertion into a cationic host matrix. PMID:24022381

  18. Ionic Resistance and Permselectivity Tradeoffs in Anion Exchange Membranes

    KAUST Repository

    Geise, Geoffrey M.

    2013-10-23

    Salinity gradient energy technologies, such as reverse electrodialysis (RED) and capacitive mixing based on Donnan potential (Capmix CDP), could help address the global need for noncarbon-based energy. Anion exchange membranes (AEMs) are a key component in these systems, and improved AEMs are needed in order to optimize and extend salinity gradient energy technologies. We measured ionic resistance and permselectivity properties of quaternary ammonium-functionalized AEMs based on poly(sulfone) and poly(phenylene oxide) polymer backbones and developed structure-property relationships between the transport properties and the water content and fixed charge concentration of the membranes. Ion transport and ion exclusion properties depend on the volume fraction of water in the polymer membrane, and the chemical nature of the polymer itself can influence fine-tuning of the transport properties to obtain membranes with other useful properties, such as chemical and dimensional stability. The ionic resistance of the AEMs considered in this study decreased by more than 3 orders of magnitude (i.e., from 3900 to 1.6 Ω m) and the permselectivity decreased by 6% (i.e., from 0.91 to 0.85) as the volume fraction of water in the polymer was varied by a factor of 3.8 (i.e., from 0.1 to 0.38). Water content was used to rationalize a tradeoff relationship between the permselectivity and ionic resistance of these AEMs whereby polymers with higher water content tend to have lower ionic resistance and lower permselectivity. The correlation of ion transport properties with water volume fraction and fixed charge concentration is discussed with emphasis on the importance of considering water volume fraction when interpreting ion transport data. © 2013 American Chemical Society.

  19. 高脂及劳倦伤脾大鼠有机阴离子转运肽oatp4a1 mRNA及蛋白表达%Organic Anion Transporting Polypeptide (oatp4a1) mRNA and Protein Expressions in High Fat and Overfatigue Impairing Pi Rats

    Institute of Scientific and Technical Information of China (English)

    董霄; 潘爱珍; 孙保国; 周厚明; 陈泽雄; 张诗军

    2012-01-01

    目的 观察有机阴离子转运肽oatp4a1在脾虚模型大鼠各组织中的表达.探讨其在水液湿浊转运中的作用机制.方法 选取6只SPF级大鼠制备劳倦伤脾模型,另选取12只大鼠随机分为空白对照组(空白组)、高脂饮食组(高脂组),每组6只.劳倦伤脾模型组(劳倦组)单号日期采用特制束缚筒,每次3h,双号日期令大鼠在冷水[(10±1)℃]中游泳7 min,连续2周.劳倦组、空白组常规标准大鼠颗粒饲料喂养12周,高脂组大鼠以高脂饲料喂养12周,均自由饮食饮水.采用RT-PCR和Western blot法检测肺、脾、肝、肾、胃、小肠、大肠组织oatp4a1 mRNA、蛋白表达.结果 劳倦组大鼠扎堆懒动,烂便,毛色粗糙,饮食饮水量减少,体重下降(P<0.05),与临床脾虚证表现基本相符,提示劳倦伤脾动物模型造模全部成功.高脂组大鼠第9周之后开始出现食欲不振,精神萎靡,嗜卧懒动,毛发疏松粗糙,晦暗无光泽等脾虚症状,形成痰湿证大鼠.与空白组比较,高脂组第9周平均体重升高(P<0.05).oatp4a1 mRNA在肺、脾、肝、肾、胃、小肠、大肠7种脏器中都有表达;各组各组织oatp4a1 mRNA表达量比较,差异均无统计学意义(P>0.05);高脂组大鼠肺、肾oatp4a1 mRNA表达量均高于肝(P<0.05).结论 oatp4a1可能是高脂伤脾大鼠机体参与湿浊转运的物质基础之一,其中肺、肾、大肠在湿浊转运中可能起着重要作用.%Objective To study organic anion transporting polypeptide (OATP) superfamily member 4a1 (oatp4a1) mRNA expression in the Pi deficiency model rats, thus exploring its mechanism for transporting and transforming the dampness. Methods Six SD rats of SPF grade were used to prepare over-fatigue impairing Pi model. Another 12 SD rats were randomly divided into the blank control group and the high fat diets group, 6 in each. The special binding tube was used for the over-fatigue impairing Pi model group on the odd day, 3 h each

  20. Presence of monovalent oxygen anions in oxides demonstrated using X-ray photoelectron spectra

    International Nuclear Information System (INIS)

    The oxygen vacancy model has been used to explain the magnetic and electrical transport properties of dilute magnetic semiconductors and resistive switching. In particular, some authors have claimed that they found a symmetric peak corresponding to the oxygen vacancies in O1s photoelectron spectra. In this paper, using X-ray photoelectron spectra with argon ion etching, it is shown that this symmetric peak may also be interpreted as being related to O1− anions, rather than to oxygen vacancies

  1. Anion photoelectron spectroscopy of radicals and clusters

    Energy Technology Data Exchange (ETDEWEB)

    Travis, Taylor R.

    1999-12-16

    Anion photoelectron spectroscopy is used to study free radicals and clusters. The low-lying {sup 2}{Sigma} and {sup 2}{Pi} states of C{sub 2n}H (n = 1--4) have been studied. The anion photoelectron spectra yielded electron affinities, term values, and vibrational frequencies for these combustion and astrophysically relevant species. Photoelectron angular distributions allowed the author to correctly assign the electronic symmetry of the ground and first excited states and to assess the degree of vibronic coupling in C{sub 2}H and C{sub 4}H. Other radicals studied include NCN and I{sub 3}. The author was able to observe the low-lying singlet and triplet states of NCN for the first time. Measurement of the electron affinity of I{sub 3} revealed that it has a bound ground state and attachment of an argon atom to this moiety enabled him to resolve the symmetric stretching progression.

  2. The chemistry of gold as an anion.

    Science.gov (United States)

    Jansen, Martin

    2008-09-01

    Due to relativistic and classical shell structure effects, the 6s orbital of gold is significantly contracted and energetically stabilized. This is reflected by a strikingly high electron affinity, and a distinct tendency to adopt negatively polarized valence states. This tutorial review focuses on the chemistry of gold as an anion, displaying the integral ionic charge number of 1-. Two synthetic approaches to compounds containing monoatomic gold anions have become available: (1) reacting elemental gold with molten caesium and an oxide, e.g. Cs2O; (2) metathesis reactions involving Au- dissolved in liquid ammonia. Both procedures have proven to be rather versatile. Aurides synthesized along these routes are surveyed, in particular with respect to their structures and bonding properties. PMID:18762832

  3. Specific anion effects in Artemia salina.

    Science.gov (United States)

    Lo Nostro, Pierandrea; Ninham, Barry W; Carretti, Emiliano; Dei, Luigi; Baglioni, Piero

    2015-09-01

    The specific anion effect on the vitality of Artemia salina was investigated by measuring the Lethal Time LT50 of the crustaceans in the presence of different sodium salts solutions at room temperature and at the same ionic strength as natural seawater. Fluoride, thiocyanate and perchlorate are the most toxic agents, while chloride, bromide and sulfate are well tolerated. The rates of oxygen consumption of brine shrimps were recorded in mixed NaCl+NaF or NaCl+NaSCN solutions as a function of time. The results are discussed in terms of the Hofmeister series, and suggest that, besides the biochemical processes that involve F(-), SCN(-) and ClO4(-), the different physico-chemical properties of the strong kosmotropic and chaotropic anions may contribute in determining their strong toxicity for A. salina. PMID:25978674

  4. Politseiuuringud kooskõlastamisele / Liivia Anion

    Index Scriptorium Estoniae

    Anion, Liivia

    2003-01-01

    1. aprillil 2003. a. moodustatud uurimistööde kooskõlastamise komisjoni tegevuse eesmärk on saada ülevaade kõrgkoolides õppivate töötajate poolt politseis korraldatavatest uurimustest, kasutada saadud infot politsei kasuks ja vältida teenistujate tööd segavate uurimuste tegemist. Komisjoni liige Liivia Anion teeb ülevaate komisjoni otsustuspädevuse valdkondadest ja töökorraldusest

  5. Several hemicyanine dyes as fluorescence chemosensors for cyanide anions

    Science.gov (United States)

    Liang, Muhan; Wang, Kangnan; Guan, Ruifang; Liu, Zhiqiang; Cao, Duxia; Wu, Qianqian; Shan, Yanyan; Xu, Yongxiao

    2016-05-01

    Four hemicyanine dyes as chemosensors for cyanide anions were synthesized easily. Their photophysical properties and recognition properties for cyanide anions were investigated. The results indicate that all the dyes can recognize cyanide anions with obvious color, absorption and fluorescence change. The recognition mechanism analysis basing on in situ 1H NMR and Job plot data indicates that to the compounds with hydroxyl group, the recognition mechanism is intramolecular hydrogen bonding interaction. However, to the compounds without hydroxyl group, cyanide anion is bonded to carbon-carbon double bond in conjugated bridge and induces N+ CH3 to neutral NCH3. Fluorescence of the compounds is almost quenched upon the addition of cyanide anions.

  6. The benzene radical anion: A computationally demanding prototype for aromatic anions

    International Nuclear Information System (INIS)

    The benzene radical anion is studied with ab initio coupled-cluster theory in large basis sets. Unlike the usual assumption, we find that, at the level of theory investigated, the minimum energy geometry is non-planar with tetrahedral distortion at two opposite carbon atoms. The anion is well known for its instability to auto-ionization which poses computational challenges to determine its properties. Despite the importance of the benzene radical anion, the considerable attention it has received in the literature so far has failed to address the details of its structure and shape-resonance character at a high level of theory. Here, we examine the dynamic Jahn-Teller effect and its impact on the anion potential energy surface. We find that a minimum energy geometry of C2 symmetry is located below one D2h stationary point on a C2h pseudo-rotation surface. The applicability of standard wave function methods to an unbound anion is assessed with the stabilization method. The isotropic hyperfine splitting constants (Aiso) are computed and compared to data obtained from experimental electron spin resonance experiments. Satisfactory agreement with experiment is obtained with coupled-cluster theory and large basis sets such as cc-pCVQZ

  7. Susceptibility of antibiotic-resistant and antibiotic-sensitive foodborne pathogens to acid anionic sanitizers.

    Science.gov (United States)

    Lopes, J A

    1998-10-01

    Acid anionic sanitizers for treatment of fruits and vegetables were prepared using ingredients generally recognized as safe by the U.S. Food and Drug Administration or anionic surfactants and organic acid food additives. They met the regulatory definition as sanitizers by showing bactericidal efficacy of 99.999% in 30 s against Staphylococcus aureus ATCC 6538 and Escherichia coli ATCC 11229. These sanitizers showed a broad spectrum of microbicidal activity against both gram-positive and gram-negative bacteria. Antibiotic-sensitive and resistant strains of Listeria monocytogenes and Salmonella typhimurium were equally susceptible to these sanitizers. The acid anionic sanitizers showed microbicidal efficacy equal to that of hypochlorite against Aeromonas hydrophila, E. coli O157:H7, L. monocytogenes, Pseudomonas aeruginosa, S. typhimurium, and S. aureus. Unlike most other sanitizers, these agents do not covalently react with organic components of food; unlike cationic agents, they do not leave residues. The acid anionic sanitizers are prepared using stable, biodegradable, and nontoxic ingredients. Rapid microbicidal activity and the ease of storage, transportation, and use make these sanitizers an attractive alternative to hypochlorite for sanitizing fruits and vegetables. PMID:9798163

  8. How Phosphorylation and ATPase Activity Regulate Anion Flux though the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR).

    Science.gov (United States)

    Zwick, Matthias; Esposito, Cinzia; Hellstern, Manuel; Seelig, Anna

    2016-07-01

    The cystic fibrosis transmembrane conductance regulator (CFTR, ABCC7), mutations of which cause cystic fibrosis, belongs to the ATP-binding cassette (ABC) transporter family and works as a channel for small anions, such as chloride and bicarbonate. Anion channel activity is known to depend on phosphorylation by cAMP-dependent protein kinase A (PKA) and CFTR-ATPase activity. Whereas anion channel activity has been extensively investigated, phosphorylation and CFTR-ATPase activity are still poorly understood. Here, we show that the two processes can be measured in a label-free and non-invasive manner in real time in live cells, stably transfected with CFTR. This study reveals three key findings. (i) The major contribution (≥90%) to the total CFTR-related ATP hydrolysis rate is due to phosphorylation by PKA and the minor contribution (≤10%) to CFTR-ATPase activity. (ii) The mutant CFTR-E1371S that is still conductive, but defective in ATP hydrolysis, is not phosphorylated, suggesting that phosphorylation requires a functional nucleotide binding domain and occurs in the post-hydrolysis transition state. (iii) CFTR-ATPase activity is inversely related to CFTR anion flux. The present data are consistent with a model in which CFTR is in a closed conformation with two ATPs bound. The open conformation is induced by ATP hydrolysis and corresponds to the post-hydrolysis transition state that is stabilized by phosphorylation and binding of chloride channel potentiators. PMID:27226582

  9. Optimized anion exchange membranes for vanadium redox flow batteries.

    Science.gov (United States)

    Chen, Dongyang; Hickner, Michael A; Agar, Ertan; Kumbur, E Caglan

    2013-08-14

    In order to understand the properties of low vanadium permeability anion exchange membranes for vanadium redox flow batteries (VRFBs), quaternary ammonium functionalized Radel (QA-Radel) membranes with three ion exchange capacities (IECs) from 1.7 to 2.4 mequiv g(-1) were synthesized and 55-60 μm thick membrane samples were evaluated for their transport properties and in-cell battery performance. The ionic conductivity and vanadium permeability of the membranes were investigated and correlated to the battery performance through measurements of Coulombic efficiency, voltage efficiency and energy efficiency in single cell tests, and capacity fade during cycling. Increasing the IEC of the QA-Radel membranes increased both the ionic conductivity and VO(2+) permeability. The 1.7 mequiv g(-1) IEC QA-Radel had the highest Coulombic efficiency and best cycling capacity maintenance in the VRFB, while the cell's voltage efficiency was limited by the membrane's low ionic conductivity. Increasing the IEC resulted in higher voltage efficiency for the 2.0 and 2.4 mequiv g(-1) samples, but the cells with these membranes displayed reduced Coulombic efficiency and faster capacity fade. The QA-Radel with an IEC of 2.0 mequiv g(-1) had the best balance of ionic conductivity and VO(2+) permeability, achieving a maximum power density of 218 mW cm(-2) which was higher than the maximum power density of a VRFB assembled with a Nafion N212 membrane in our system. While anion exchange membranes are under study for a variety of VRFB applications, this work demonstrates that the material parameters must be optimized to obtain the maximum cell performance. PMID:23799776

  10. Supramolecular chemistry of selective anion recognition for anions of environmental relevance. 1998 annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    Bowman-James, K.; Wilson, G.S.; Kuczera, K. [Univ. of Kansas, Lawrence, KS (US); Moyer, B. [Oak Ridge National Lab., TN (US)

    1998-06-01

    'This project has as its focus the design and synthesis of polyammonium macrocyclic receptors for oxoanions of environmental importance. The basic research aspects of this project involve: (1) synthesis (and the search for improved synthetic methods); (2) solid state structure determination and thermodynamics studies (to ascertain structural criteria for and strength of anion binding); and (3) molecular dynamics simulations (to assess solution characteristics of the interactions between anions and their receptors). Applications-oriented goals include the fabrication of more selective anion-selective electrodes and the use of these compounds in liquid-liquid separations. The latter goal comprises the subcontract with Dr. Bruce Moyer at Oak Ridge National Laboratory. This report summarizes work after 1 year and 7 months of a 3-year project. To date, the authors have focussed on the design and synthesis of selective receptors for nitrate and phosphate.'

  11. Expanded Porphyrin-Anion Supramolecular Assemblies: Environmentally Responsive Sensors for Organic Solvents and Anions.

    Science.gov (United States)

    Zhang, Zhan; Kim, Dong Sub; Lin, Chung-Yon; Zhang, Huacheng; Lammer, Aaron D; Lynch, Vincent M; Popov, Ilya; Miljanić, Ognjen Š; Anslyn, Eric V; Sessler, Jonathan L

    2015-06-24

    Porphyrins have been used frequently to construct supramolecular assemblies. In contrast, noncovalent ensembles derived from expanded porphyrins, larger congeners of naturally occurring tetrapyrrole macrocycles, are all but unknown. Here we report a series of expanded porphyrin-anion supramolecular assemblies. These systems display unique environmentally responsive behavior. Addition of polar organic solvents or common anions to the ensembles leads to either a visible color change, a change in the fluorescence emission features, or differences in solubility. The actual response, which could be followed easily by the naked eye, was found to depend on the specifics of the assembly, as well as the choice of analyte. Using the ensembles of this study, it proved possible to differentiate between common solvents, such as diethyl ether, THF, ethyl acetate, acetone, alcohol, acetonitrile, DMF, and DMSO, identify complex solvent systems, as well as distinguish between the fluoride, chloride, bromide, nitrate, and sulfate anions. PMID:25965790

  12. Anionic complexes of Cu(I) with the closo-decaborate anion

    International Nuclear Information System (INIS)

    General procedures for synthesis of anionic Cu(I) complexes with the closo-decaborate anion were worked out; they make it possible to prepare coordination compounds with a wide set of organic cations. The interaction of onium closo-decaborates with [Cu2B10H10] in acetonitrile acidified with anhydrous trifluoroacetic acid was found to be the most effective synthetic method that secures high yield and quality of the obtained products. The structure of {(C2H5)3NH[CuB10H10]} was determined by X-ray diffraction analysis

  13. Organic superconductors with an incommensurate anion structure

    Directory of Open Access Journals (Sweden)

    Tadashi Kawamoto and Kazuo Takimiya

    2009-01-01

    Full Text Available Superconducting incommensurate organic composite crystals based on the methylenedithio-tetraselenafulvalene (MDT-TSF series donors, where the energy band filling deviates from the usual 3/4-filled, are reviewed. The incommensurate anion potential reconstructs the Fermi surface for both (MDT-TSF(AuI20.436 and (MDT-ST(I30.417 neither by the fundamental anion periodicity q nor by 2q, but by 3q, where MDT-ST is 5H-2-(1,3-dithiol-2-ylidene-1,3-diselena-4,6-dithiapentalene, and q is the reciprocal lattice vector of the anion lattice. The selection rule of the reconstructing vectors is associated with the magnitude of the incommensurate potential. The considerably large interlayer transfer integral and three-dimensional superconducting properties are due to the direct donor–donor interactions coming from the characteristic corrugated conducting sheet structure. The materials with high superconducting transition temperature, Tc, have large ratios of the observed cyclotron masses to the bare ones, which indicates that the strength of the many-body effect is the major determinant of Tc. (MDT-TS(AuI20.441 shows a metal–insulator transition at TMI=50 K, where MDT-TS is 5H-2-(1,3-diselenol-2-ylidene-1,3,4,6-tetrathiapentalene, and the insulating phase is an antiferromagnet with a high Néel temperature (TN=50 K and a high spin–flop field (Bsf=6.9 T. There is a possibility that this material is an incommensurate Mott insulator. Hydrostatic pressure suppresses the insulating state and induces superconductivity at Tc=3.2 K above 1.05 GPa, where Tc rises to the maximum, Tcmax=4.9 K at 1.27 GPa. This compound shows a usual temperature–pressure phase diagram, in which the superconducting phase borders on the antiferromagnetic insulating phase, despite the unusual band filling.

  14. Infrared Spectroscopy of Discrete Uranyl Anion Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Gary S. Groenewold; Anita K. Gianotto; Michael E. McIlwain; Michael J. Van Stipdonk; Michael Kullman; Travis J. Cooper; David T. Moore; Nick Polfer; Jos Oomens; Ivan Infante; Lucas Visscher; Bertrand Siboulet; Wibe A. de Jong

    2007-12-01

    The Free-Electron Laser for Infrared Experiments, FELIX, was used to study the wavelength-resolved multiphoton dissociation of discrete, gas phase uranyl (UO22+) complexes containing a single anionic ligand (A), with or without ligated solvent molecules (S). The apparent uranyl antisymmetric and symmetric stretching frequencies were measured for complexes with general formula [UO2A(S)n]+, where A was either hydroxide, methoxide or acetate, S was water, ammonia, acetone or acetonitrile, and n = 0-2. The values for the antisymmetric stretching frequency for uranyl ligated with only an anion ([UO2A]+) were as low or lower than measurements for [UO2]2+ ligated with as many as five strong neutral donor ligands, and are comparable to solution phase values. This result was surprising because initial DFT calculations using B3LYP predicted values that were 30 – 40 cm-1 higher, consistent with intuition but not with the data. Modification of the basis set and use of alternative functionals improved computational accuracy for the methoxide and acetate complexes, but calculated values for the hydroxide were greater than the measurement regardless of the computational method used. Attachment of a neutral donor ligand S to [UO2A]+ produced [UO2AS]+, which resulted only very modest changes to the uranyl frequency, and did not universally shift values lower. DFT calculations for [UO2AS]+ were in accord with trends in the data, and showed that attachment of the solvent was accommodated by weakening of the U-anion bond as well as the uranyl. When uranyl frequencies were compared for [UO2AS]+ species having different solvent neutrals, values decreased with increasing neutral nucleophilicity.

  15. Infared Spectroscopy of Discrete Uranyl Anion Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Groenewold, G. S.; Gianotto, Anita K.; McIIwain, Michael E.; Van Stipdonk, Michael J.; Kullman, Michael; Moore, David T.; Polfer, Nick; Oomens, Jos; Infante, Ivan A.; Visscher, Lucas; Siboulet, Bertrand; De Jong, Wibe A.

    2008-01-24

    The Free-Electron Laser for Infrared Experiments (FELIX) w 1 as used to study the wavelength-resolved multiple photon photodissociation of discrete, gas phase uranyl (UO2 2 2+) complexes containing a single anionic ligand (A), with or without ligated solvent molecules (S). The uranyl antisymmetric and symmetric stretching frequencies were measured for complexes with general formula [UO2A(S)n]+, where A was either hydroxide, methoxide, or acetate; S was water, ammonia, acetone, or acetonitrile; and n = 0-3. The values for the antisymmetric stretching frequency for uranyl ligated with only an anion ([UO2A]+) were as low or lower than measurements for [UO2]2+ ligated with as many as five strong neutral donor ligands, and are comparable to solution phase values. This result was surprising because initial DFT calculations predicted values that were 30–40 cm-1 higher, consistent with intuition but not with the data. Modification of the basis sets and use of alternative functionals improved computational accuracy for the methoxide and acetate complexes, but calculated values for the hydroxide were greater than the measurement regardless of the computational method used. Attachment of a neutral donor ligand S to [UO2A]+ produced [UO2AS]+, which produced only very modest changes to the uranyl antisymmetric stretch frequency, and did not universally shift the frequency to lower values. DFT calculations for [UO2AS]+ were in accord with trends in the data, and showed that attachment of the solvent was accommodated by weakening of the U-anion bond as well as the uranyl. When uranyl frequencies were compared for [UO2AS]+ species having different solvent neutrals, values decreased with increasing neutral nucleophilicity.

  16. Infrared Spectroscopy of Discrete Uranyl Anion Complexes

    International Nuclear Information System (INIS)

    The Free-Electron Laser for Infrared Experiments (FELIX) w 1 as used to study the wavelength-resolved multiple photon photodissociation of discrete, gas phase uranyl (UO2 2 2+) complexes containing a single anionic ligand (A), with or without ligated solvent molecules (S). The uranyl antisymmetric and symmetric stretching frequencies were measured for complexes with general formula [UO2A(S)n]+, where A was either hydroxide, methoxide, or acetate; S was water, ammonia, acetone, or acetonitrile; and n = 0-3. The values for the antisymmetric stretching frequency for uranyl ligated with only an anion ([UO2A]+) were as low or lower than measurements for [UO2]2+ ligated with as many as five strong neutral donor ligands, and are comparable to solution phase values. This result was surprising because initial DFT calculations predicted values that were 30-40 cm-1 higher, consistent with intuition but not with the data. Modification of the basis sets and use of alternative functionals improved computational accuracy for the methoxide and acetate complexes, but calculated values for the hydroxide were greater than the measurement regardless of the computational method used. Attachment of a neutral donor ligand S to [UO2A]+ produced [UO2AS]+, which produced only very modest changes to the uranyl antisymmetric stretch frequency, and did not universally shift the frequency to lower values. DFT calculations for [UO2AS]+ were in accord with trends in the data, and showed that attachment of the solvent was accommodated by weakening of the U-anion bond as well as the uranyl. When uranyl frequencies were compared for [UO2AS]+ species having different solvent neutrals, values decreased with increasing neutral nucleophilicity

  17. Effect of anionic surfactant concentration on the variable range hopping conduction in polypyrrole nanoparticles

    Science.gov (United States)

    Rawal, Ishpal; Kaur, Amarjeet

    2014-01-01

    The mechanism of charge transport in polypyrrole (PPy) nanoparticles prepared with different concentrations (5 to 30 mM) of anionic surfactant (sodium dodecyl sulfate) is reported. Transmission electron microscopy technique confirms the formation of PPy nanoparticles of sizes ˜52 to 28 nm under surfactant directed approach. The room temperature electrical conductivity of the prepared nanoparticles found to increase from 3 to 22 S/cm with surfactant concentration. The temperature dependent activation energy rules out the possibility of band conduction mechanism in the prepared PPy nanoparticles and thus the synthesized nanoparticles are analyzed under variable range hopping (VRH) model for conduction mechanism. The PPy nanoparticles, reduced with liquid ammonia, hold 3D VRH conduction mechanism for the charge transport. However, in the doped samples, some deviation from 3D VRH conduction behavior at higher temperatures (>150 K) has been observed. This may be attributed to the presence of anionic surfactant in these samples. The doping of anionic surfactant causes rise in conducting islands, which may lead to the change in the shape/distribution of density of states governed by Gaussian or exponential type near Fermi level.

  18. Perspective: Electrospray photoelectron spectroscopy: From multiply-charged anions to ultracold anions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lai-Sheng, E-mail: Lai-Sheng-Wang@brown.edu [Department of Chemistry, Brown University, Providence, Rhode Island 02912 (United States)

    2015-07-28

    Electrospray ionization (ESI) has become an essential tool in chemical physics and physical chemistry for the production of novel molecular ions from solution samples for a variety of spectroscopic experiments. ESI was used to produce free multiply-charged anions (MCAs) for photoelectron spectroscopy (PES) in the late 1990 s, allowing many interesting properties of this class of exotic species to be investigated. Free MCAs are characterized by strong intramolecular Coulomb repulsions, which create a repulsive Coulomb barrier (RCB) for electron emission. The RCB endows many fascinating properties to MCAs, giving rise to meta-stable anions with negative electron binding energies. Recent development in the PES of MCAs includes photoelectron imaging to examine the influence of the RCB on the electron emission dynamics, pump-probe experiments to examine electron tunneling through the RCB, and isomer-specific experiments by coupling PES with ion mobility for biological MCAs. The development of a cryogenically cooled Paul trap has led to much better resolved PE spectra for MCAs by creating vibrationally cold anions from the room temperature ESI source. Recent advances in coupling the cryogenic Paul trap with PE imaging have allowed high-resolution PE spectra to be obtained for singly charged anions produced by ESI. In particular, the observation of dipole-bound excited states has made it possible to conduct vibrational autodetachment spectroscopy and resonant PES, which yield much richer vibrational spectroscopic information for dipolar free radicals than traditional PES.

  19. Perspective: Electrospray photoelectron spectroscopy: From multiply-charged anions to ultracold anions

    International Nuclear Information System (INIS)

    Electrospray ionization (ESI) has become an essential tool in chemical physics and physical chemistry for the production of novel molecular ions from solution samples for a variety of spectroscopic experiments. ESI was used to produce free multiply-charged anions (MCAs) for photoelectron spectroscopy (PES) in the late 1990 s, allowing many interesting properties of this class of exotic species to be investigated. Free MCAs are characterized by strong intramolecular Coulomb repulsions, which create a repulsive Coulomb barrier (RCB) for electron emission. The RCB endows many fascinating properties to MCAs, giving rise to meta-stable anions with negative electron binding energies. Recent development in the PES of MCAs includes photoelectron imaging to examine the influence of the RCB on the electron emission dynamics, pump-probe experiments to examine electron tunneling through the RCB, and isomer-specific experiments by coupling PES with ion mobility for biological MCAs. The development of a cryogenically cooled Paul trap has led to much better resolved PE spectra for MCAs by creating vibrationally cold anions from the room temperature ESI source. Recent advances in coupling the cryogenic Paul trap with PE imaging have allowed high-resolution PE spectra to be obtained for singly charged anions produced by ESI. In particular, the observation of dipole-bound excited states has made it possible to conduct vibrational autodetachment spectroscopy and resonant PES, which yield much richer vibrational spectroscopic information for dipolar free radicals than traditional PES

  20. Preorganized anion traps for exploiting anion-π interactions: an experimental and computational study.

    Science.gov (United States)

    Bretschneider, Anne; Andrada, Diego M; Dechert, Sebastian; Meyer, Steffen; Mata, Ricardo A; Meyer, Franc

    2013-12-01

    1,3-Bis(pentafluorophenyl-imino)isoindoline (A(F)) and 3,6-di-tert-butyl-1,8-bis(pentafluorophenyl)-9H-carbazole (B(F)) have been designed as preorganized anion receptors that exploit anion-π interactions, and their ability to bind chloride and bromide in various solvents has been evaluated. Both receptors A(F) and B(F) are neutral but provide a central NH hydrogen bond that directs the halide anion into a preorganized clamp of the two electron-deficient appended arenes. Crystal structures of host-guest complexes of A(F) with DMSO, Cl(-), or Br(-) (A(F):DMSO, A(F):Cl(-), and A(2)(F):Br(-)) reveal that in all cases the guest is located in the cleft between the perfluorinated flaps, but NMR spectroscopy shows a more complex situation in solution because of E,Z/Z,Z isomerism of the host. In the case of the more rigid receptor B(F), Job plots evidence 1:1 complex formation with Cl(-) and Br(-), and association constants up to 960 M(-1) have been determined depending on the solvent. Crystal structures of B(F) and B(F):DMSO visualize the distinct preorganization of the host for anion-π interactions. The reference compounds 1,3-bis(2-pyrimidylimino)isoindoline (A(N)) and 3,6-di-tert-butyl-1,8-diphenyl-9H-carbazole (B(H)), which lack the perfluorinated flaps, do not show any indication of anion binding under the same conditions. A detailed computational analysis of the receptors A(F) and B(F) and their host-guest complexes with Cl(-) or Br(-) was carried out to quantify the interactions in play. Local correlation methods were applied, allowing for a decomposition of the ring-anion interactions. The latter were found to contribute significantly to the stabilization of these complexes (about half of the total energy). Compounds A(F) and B(F) represent rare examples of neutral receptors that are well preorganized for exploiting anion-π interactions, and rare examples of receptors for which the individual contributions to the binding energy have been quantified. PMID

  1. Photoelectron Spectroscopy and Theoretical Studies of Anion-pi Interactions: Binding Strength and Anion Specificity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jian; Zhou, Bin; Sun, Zhenrong; Wang, Xue B.

    2015-01-01

    Proposed in theory and confirmed to exist, anion–π interactions have been recognized as new and important non-covalent binding forces. Despite extensive theoretical studies, numerous crystal structural identifications, and a plethora of solution phase investigations, intrinsic anion–π interaction strengths that are free from complications of condensed phases’ environments, have not been directly measured in the gas phase. Herein we present a joint photoelectron spectroscopic and theoretical study on this subject, in which tetraoxacalix[2]arene[2]triazine 1, an electron-deficient and cavity self-tunable macrocyclic was used as a charge-neutral molecular host to probe its interactions with a series of anions with distinctly different shapes and charge states (spherical halides Cl⁻, Br⁻, I⁻, linear thiocyanate SCN⁻, trigonal planar nitrate NO₃⁻, pyramidic iodate IO₃⁻, and tetrahedral sulfate SO₄²⁻). The binding energies of the resultant gaseous 1:1 complexes (1•Cl⁻,1•Br⁻, 1•I⁻, 1•SCN⁻, 1•NO₃⁻, 1•IO₃⁻ and 1•SO₄²⁻) were directly measured experimentally, exhibiting substantial non-covalent interactions with pronounced anion specific effects. The binding strengths of Cl⁻, NO₃⁻, IO₃⁻ with 1 are found to be strongest among all singly charged anions, amounting to ca. 30 kcal/mol, but only about 40% of that between 1 and SO₄²⁻. Quantum chemical calculations reveal that all anions reside in the center of the cavity of 1 with anion–π binding motif in the complexes’ optimized structures, where 1 is seen to be able to self-regulate its cavity structure to accommodate anions of different geometries and three-dimensional shapes. Electron density surface and natural bond orbital charge distribution analysis further support anion–π binding formation. The calculated binding energies of the anions and 1 nicely reproduce the experimentally estimated electron binding energy increase. This work

  2. Anions in laser-induced plasmas

    Science.gov (United States)

    Shabanov, S. V.; Gornushkin, I. B.

    2016-07-01

    The equation of state for plasmas containing negative atomic and molecular ions (anions) is modeled. The model is based on the assumption that all ionization processes and chemical reactions are at local thermal equilibrium and the Coulomb interaction in the plasma is described by the Debye-Hückel theory. In particular, the equation of state is obtained for plasmas containing the elements Ca, Cl, C, Si, N, and Ar. The equilibrium reaction constants are calculated using the latest experimental and ab initio data of spectroscopic constants for the molecules CaCl_2, CaCl, Cl_2, N_2, C_2, Si_2, CN, SiN, SiC, and their positive and negative ions. The model is applied to laser-induced plasmas (LIPs) by including the equation of state into a fluid dynamic numerical model based on the Navier-Stokes equations describing an expansion of LIP plumes into an ambient gas as a reactive viscous flow with radiative losses. In particular, the formation of anions Cl-, C-, Si-, {{Cl}}2^{ - }, {{Si}}2^{ - }, {{C}}2^{ - }, CN-, SiC-, and SiN- in LIPs is investigated in detail.

  3. Porating anion-responsive copolymeric gels.

    Science.gov (United States)

    England, Dustin; Yan, Feng; Texter, John

    2013-09-24

    A polymerizable ionic liquid surfactant, 1-(11-acryloyloxyundecyl)-3-methylimidiazolium bromide (ILBr), was copolymerized with methyl methacrylate (MMA) in aqueous microemulsions at 30% (ILBr w/w) and various water to MMA ratios. The ternary phase diagram of the ILBr/MMA/water system was constructed at 25 and 60 °C. Homopolymers and copolymers of ILBr and MMA were produced by thermally initiated chain radical microemulsion polymerization at various compositions in bicontinuous and reverse microemulsion subdomains. Microemulsion polymerization reaction products varied from being gel-like to solid, and these materials were analyzed by thermal and scanning electron microscopy methods. Microemulsion polymerized materials were insoluble in all solvents tested, consistent with light cross-linking. Ion exchange between Br(-) and PF6(-) in these copolymeric materials resulted in the formation of open-cell porous structures in some of these materials, as was confirmed by scanning electron microscopy (SEM). Several compositions illustrate the capture of prepolymerization nanoscale structure by thermally initiated polymerization, expanding the domain of compositions exhibiting this feat and yet to be demonstrated in any other system. Regular cylindrical pores in interpenetrating ILBr-co-MMA and PMMA networks are produced by anion exchange in the absence of templates. A percolating cluster/bicontinuous transition is "captured" by SEM after using anion exchange to visualize the mixed cluster/pore morphology. Some design principles for achieving this capture and for obtaining stimuli responsive solvogels are articulated, and the importance of producing solvogels in capturing the nanoscale is highlighted. PMID:23968242

  4. Protein Camouflage: Supramolecular Anion Recognition by Ubiquitin.

    Science.gov (United States)

    Mallon, Madeleine; Dutt, Som; Schrader, Thomas; Crowley, Peter B

    2016-04-15

    Progress in the field of bio-supramolecular chemistry, the bottom-up assembly of protein-ligand systems, relies on a detailed knowledge of molecular recognition. To address this issue, we have characterised complex formation between human ubiquitin (HUb) and four supramolecular anions. The ligands were: pyrenetetrasulfonic acid (4PSA), p-sulfonato-calix[4]arene (SCLX4), bisphosphate tweezers (CLR01) and meso-tetrakis (4-sulfonatophenyl)porphyrin (TPPS), which vary in net charge, size, shape and hydrophobicity. All four ligands induced significant changes in the HSQC spectrum of HUb. Chemical shift perturbations and line-broadening effects were used to identify binding sites and to quantify affinities. Supporting data were obtained from docking simulations. It was found that these weakly interacting ligands bind to extensive surface patches on HUb. A comparison of the data suggests some general indicators for the protein-binding specificity of supramolecular anions. Differences in binding were observed between the cavity-containing and planar ligands. The former had a preference for the arginine-rich, flexible C terminus of HUb. PMID:26818656

  5. Advancements in Anion Exchange Membrane Cations

    Energy Technology Data Exchange (ETDEWEB)

    Sturgeon, Matthew R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Long, Hai [National Renewable Energy Lab. (NREL), Golden, CO (United States); Park, Andrew M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Pivovar, Bryan S. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-10-15

    Anion-exchange membrane fuel cells (AME-FCs) are of increasingly popular interest as they enable the use of non-Pt fuel cell catalysts, the primary cost limitation of proton exchange membrane fuel cells. Benzyltrimethyl ammonium (BTMA) is the standard cation that has historically been utilized as the hydroxide conductor in AEMs. Herein we approach AEMs from two directions. First and foremost we study the stability of several different cations in a hydroxide solution at elevated temperatures. We specifically targeted BTMA and methoxy and nitro substituted BTMA. We've also studied the effects of adding an akyl spacer units between the ammonium cation and the phenyl group. In the second approach we use computational studies to predict stable ammonium cations, which are then synthesized and tested for stability. Our unique method to study cation stability in caustic conditions at elevated temperatures utilizes Teflon Parr reactors suitable for use under various temperatures and cation concentrations. NMR analysis was used to determine remaining cation concentrations at specific time points with GCMS analysis verifying product distribution. We then compare the experimental results with calculated modeling stabilities. Our studies show that the electron donating methoxy groups slightly increase stability (compared to that of BTMA), while the electron withdrawing nitro groups greatly decrease stability in base. These results give insight into possible linking strategies to be employed when tethering a BTMA like ammonium cation to a polymeric backbone; thus synthesizing an anion exchange membrane.

  6. Reversible photochromism of an N-salicylidene aniline anion

    OpenAIRE

    Jacquemin, Pierre-Loïc; Robeyns, Koen; Devillers, Michel; Garcia, Yann

    2014-01-01

    The first N-salicylidene aniline anion showing reversible solid state thermochromic and photochromic properties is described. The photo-isomerization involves a trans-keto form which is stabilized thanks to the local anion surrounding. This photochromic anion can be used as a guest for the preparation of hybrid materials by insertion into a cationic host matrix. © 2014 The Royal Society of Chemistry.

  7. Anion concurrence and anion selectivity in the sorption of radionuclides by organotones

    International Nuclear Information System (INIS)

    Some long-lived and radiologically important nuclear fission products, such as I-129 (half-life t1/2 = 1,6 . 107 a), Tc-99 (t1/2 = 2,1 . 105 a), and Se-79 (t1/2 = 6,5 . 104 a) are anionic in aqueous environments. This study focuses on the adsorption of such anions to organoclays and the understanding of the selectivity of the process. The organoclays used in this study were prepared from a bentonite (MX-80) and a vermiculite clay, and the cationic surfactants hexadcylpyridium, hexadecyltrimethylammonium, and benzethonium. Surfactant adsorption to the bentonite exceeds the cation exchange capacity of the clay, with the surplus positive charge being balanced by the co-adsorption of chloride. The interlayer distance of the bentonites is increased sufficiently to contain bi- and pseudotrimolecular structures of the surfactants. Adsorption experiments were carried out using the batch technique. Anion adsorption of iodide, perrhenate, selenite, nitrate, and sulphate is mainly due to ion exchange with chloride. As an additional adsorption mechanism, the incorporation of inorganic ion pairs into the interlayer space of the clay is proposed as a result of experiments showing differences in the adsorption levels of sodium and potassium iodide. Anion adsorption results show a clear selectivity of the organoclays, with the affinity sequence being: ReO-4 > I- > NO-3 > Cl- > SO2-4 > SeO2-3. This sequence corresponds to the sequence of increasing hydration energies of the anions, thus selectivity could be due to the process of minimization of free energy of the system. (orig.)

  8. Hypotonicity induced K+ and anion conductive pathways activation in eel intestinal epithelium

    DEFF Research Database (Denmark)

    Lionetto, M G; Giordano, M E; De Nuccio, F; Nicolardi, G; Hoffmann, E K; Schettino, T

    2005-01-01

    electrogenic V(te) and I(sc) responses to hypotonicity resulted from the activation of different K+ and anion conductive pathways on the apical and basolateral membranes of the epithelium: (a) iberiotoxin-sensitive K+ channels on the apical and basolateral membrane, (b) apamin-sensitive K+ channels mainly on...... the basolateral membrane, (c) DIDS-sensitive anion channels on the apical membrane. The functional integrity of the basal Cl- conductive pathway on the basolateral membrane is also required. The electrophysiological response to hypotonic stress was completely abolished by Ca2+ removal from the Ringer...... activation of 'emergency' systems of rapid cell volume regulation is fundamental in their physiology. The aim of the present work was to study the physiological response to hypotonic stress in a salt-transporting epithelium, the intestine of the euryhaline teleost Anguilla anguilla. Eel intestinal epithelium...

  9. Ab initio studies of complexation of anions to neutral species

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Patrik [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden)]. E-mail: patrikj@fy.chalmers.se; Jacobsson, Per [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden)

    2005-06-30

    The complexation of simple anions (F{sup -} and Cl{sup -}) to different neutral species, anion-coordinating agents, has been studied using electronic structure calculations. The obtained changes in the equilibrium constants for salt dissolution reactions in different typical electrolyte systems are reported. In addition the lithium ion affinities of the obtained anionic complexes have been calculated. Using the present results we discuss strategies for future usage of anion complexing agents and make recommendations of salt and agent combinations for better lithium battery electrolyte performance.

  10. Inhibition of nuclear waste solutions containing multiple aggressive anions

    International Nuclear Information System (INIS)

    The inhibition of localized corrosion of carbon steel in caustic, high-level radioactive waste solutions was studied using cyclic potentiodynamic polarization scans supplemented by partially immersed coupon tests. The electrochemical tests provided a rapid and accurate means of determining the relationship between the minimum inhibitor requirements and the concentration of the aggressive anions in this system. Nitrate, sulfate, chloride, and fluoride were identified as aggressive anions; however, no synergistic effects were observed between these anions. This observation may have important theoretical implications because it tends to contradict the behavior of aggressive anions as predicted by existing theories for localized corrosion

  11. Identification and characterization of anion binding sites in RNA.

    Science.gov (United States)

    Kieft, Jeffrey S; Chase, Elaine; Costantino, David A; Golden, Barbara L

    2010-06-01

    Although RNA molecules are highly negatively charged, anions have been observed bound to RNA in crystal structures. It has been proposed that anion binding sites found within isolated RNAs represent regions of the molecule that could be involved in intermolecular interactions, indicating potential contact points for negatively charged amino acids from proteins or phosphate groups from an RNA. Several types of anion binding sites have been cataloged based on available structures. However, currently there is no method for unambiguously assigning anions to crystallographic electron density, and this has precluded more detailed analysis of RNA-anion interaction motifs and their significance. We therefore soaked selenate into two different types of RNA crystals and used the anomalous signal from these anions to identify binding sites in these RNA molecules unambiguously. Examination of these sites and comparison with other suspected anion binding sites reveals features of anion binding motifs, and shows that selenate may be a useful tool for studying RNA-anion interactions. PMID:20410239

  12. Aluminum Zintl anion moieties within sodium aluminum clusters

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haopeng; Zhang, Xinxing; Ko, Yeon Jae; Grubisic, Andrej; Li, Xiang; Ganteför, Gerd; Bowen, Kit H., E-mail: AKandalam@wcupa.edu, E-mail: kiran@mcneese.edu, E-mail: kbowen@jhu.edu [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Schnöckel, Hansgeorg [Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Eichhorn, Bryan W. [Department of Chemistry, University of Maryland at College Park, College Park, Maryland 20742 (United States); Lee, Mal-Soon; Jena, P. [Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Kandalam, Anil K., E-mail: AKandalam@wcupa.edu, E-mail: kiran@mcneese.edu, E-mail: kbowen@jhu.edu [Department of Physics, West Chester University of Pennsylvania, West Chester, Pennsylvania 19383 (United States); Kiran, Boggavarapu, E-mail: AKandalam@wcupa.edu, E-mail: kiran@mcneese.edu, E-mail: kbowen@jhu.edu [Department of Chemistry, McNeese State University, Lake Charles, Louisiana 70609 (United States)

    2014-02-07

    Through a synergetic combination of anion photoelectron spectroscopy and density functional theory based calculations, we have established that aluminum moieties within selected sodium-aluminum clusters are Zintl anions. Sodium–aluminum cluster anions, Na{sub m}Al{sub n}{sup −}, were generated in a pulsed arc discharge source. After mass selection, their photoelectron spectra were measured by a magnetic bottle, electron energy analyzer. Calculations on a select sub-set of stoichiometries provided geometric structures and full charge analyses for both cluster anions and their neutral cluster counterparts, as well as photodetachment transition energies (stick spectra), and fragment molecular orbital based correlation diagrams.

  13. Approach to the Patient With a Negative Anion Gap.

    Science.gov (United States)

    Emmett, Michael

    2016-01-01

    When anion gap calculation generates a very small or negative number, an explanation must be sought. Sporadic (nonreproducible) measurement errors and systematic (reproducible) laboratory errors must be considered. If an error is ruled out, 2 general possibilities exist. A true anion gap reduction can be generated by either reduced concentrations of unmeasured anions such as albumin or increased concentrations of unmeasured cations such as magnesium, calcium, or lithium. This teaching case describes a patient with aspirin (salicylate) poisoning whose anion gap was markedly reduced (-47 mEq/L). The discussion systematically reviews the possibilities and provides the explanation for this unusual laboratory result. PMID:26363848

  14. Making a match for Valinomycin: steroidal scaffolds in the design of electroneutral, electrogenic anion carriers.

    Science.gov (United States)

    Valkenier, Hennie; Davis, Anthony P

    2013-12-17

    The natural product Valinomycin is a well-known transmembrane cation carrier. Despite being uncharged, this molecule can extract potassium ions from water without counterions and ferry them through a membrane interior. Because it only transports positive ions, it is electrogenic, mediating a flow of charge across the membrane. Equivalent agents for anions would be valuable research tools and may have therapeutic applications, especially in the treatment of "channelopathies" such as cystic fibrosis. However, no such molecules have been found in nature. In this Account, we describe our research toward synthetic and rationally designed "anti-Valinomycins". As our core approach to this problem, we used the steroid nucleus, provided by cholic acid, as a scaffold for the assembly of anion receptors. By positioning H-bond donors on this framework, especially urea and thiourea groups in conformationally constrained axial positions, we created binding sites capable of exceptionally high affinities (up to 10(11) M(-1) for R4N(+)Cl(-) in chloroform). The extended hydrocarbon surface of the steroid helped to maintain compatibility with nonpolar media. When we tested these "cholapods" for chloride transport in vesicles, they provided the first evidence for electrogenic anion transport mediated by electroneutral organic carriers: in other words, they are the first authenticated anti-Valinomycins. They also proved active in live cells that we grew and assayed in an Ussing chamber. In subsequent work, we have shown that the cholapods can exhibit very high activities, with transport observed down to carrier/lipid ratios of 1:250,000. We also understand some of the effects of structure on the activity of these molecules. For example, in most cases, powerful transporters also act as powerful receptors. On the other hand, some modifications which favor binding do not promote transport. We gained functional advantages by cyclizing the cholapod architecture, which encloses the anion

  15. Cation and anion dynamics in the fast-ion conducting rotor phase of 7Li2SO4

    International Nuclear Information System (INIS)

    Complete text of publication follows. At 848 K, lithium sulfate undergoes a first-order phase transition. The high-temperature cubic a phase is a good cation conductor. At the same time, the oxo-anions are rotationally disordered. There has been a long debate about whether and how the rapid anion reorientation might enhance the canon transport through the crystal. We have performed quasielastic neutron scattering experiments on 7Li2SO4 in order to examine both anion and cation dynamics in this material. At Q -1, the quasielastic linewidth varies as DQ2 where D represents the Li tracer diffusion coefficient. At higher Q, we find a wave-like structure with linewidth maxima at 1.4 A-1 and 2.5 A-1 and a minimum at 1.9 A-1. This behavior is typical of coherent diffusion (7Li scatters both coherently and incoherently). We also see, at higher Q, a (coherent) quasielastic contribution from the oxygen nuclei due to the anion reorientation. Oxygen scattering is also found in the sodium cation conducting rotor phase of Na3PO4 where it is the predominant quasielastic component. Since the quasielastic scattering of 7Li2SO4 contains both cation and anion contributions, we perform classical molecular dynamics studies based on pair potentials from the literature. Results of these simulations are compared to the experimental dynamic structure factors. (author)

  16. Structural evolution of small ruthenium cluster anions

    Energy Technology Data Exchange (ETDEWEB)

    Waldt, Eugen [Institut für Nanotechnologie, Karlsruher Institut für Technologie, Postfach 3640, 76021 Karlsruhe (Germany); Hehn, Anna-Sophia; Ahlrichs, Reinhart [Institute für Physikalische Chemie, Karlsruher Institut für Technologie, Kaiserstrasse 12, 76128 Karlsruhe (Germany); Kappes, Manfred M.; Schooss, Detlef, E-mail: detlef.schooss@kit.edu [Institut für Nanotechnologie, Karlsruher Institut für Technologie, Postfach 3640, 76021 Karlsruhe (Germany); Institute für Physikalische Chemie, Karlsruher Institut für Technologie, Kaiserstrasse 12, 76128 Karlsruhe (Germany)

    2015-01-14

    The structures of ruthenium cluster anions have been investigated using a combination of trapped ion electron diffraction and density functional theory computations in the size range from eight to twenty atoms. In this size range, three different structural motifs are found: Ru{sub 8}{sup −}–Ru{sub 12}{sup −} have simple cubic structures, Ru{sub 13}{sup −}–Ru{sub 16}{sup −} form double layered hexagonal structures, and larger clusters form close packed motifs. For Ru{sub 17}{sup −}, we find hexagonal close packed stacking, whereas octahedral structures occur for Ru{sub 18}{sup −}–Ru{sub 20}{sup −}. Our calculations also predict simple cubic structures for the smaller clusters Ru{sub 4}{sup −}–Ru{sub 7}{sup −}, which were not accessible to electron diffraction measurements.

  17. Advanced polymer chemistry of organometallic anions

    Energy Technology Data Exchange (ETDEWEB)

    Chamberlin, R.M.; Abney, K.D. [Los Alamos National Lab., NM (United States); Balaich, G.J.; Fino, S.A. [Air Force Academy, CO (United States)

    1997-11-01

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of the project was to prepare and characterize new polymers incorporating cobalt dicarbollide. Specific goals were to prepare polymerizable cobalt dicarbollide monomers using the nucleophilic substitution route discovered in laboratories and to establish the reaction conditions required to form polymers from these complexes. This one-year project resulted in two publications (in press), and provided the foundation for further investigations into polymer synthesis and characterization using cobalt dicarbollide and other metallocarboranes. Interest in synthesizing organometallic polymers containing the cobalt bis(dicarbollide) anion is motivated by their possible application as cation exchange materials for the remediation of cesium-137 and strontium-90 from nuclear wastes.

  18. Anion binding by biotin[6]uril in water

    DEFF Research Database (Denmark)

    Lisbjerg, Micke; Nielsen, Bjarne Enrico; Milhøj, Birgitte Olai; Sauer, Stephan P. A.; Pittelkow, Michael

    2015-01-01

    In this contribution we show that the newly discovered 6 + 6 biotin-formaldehyde macrocycle Biotin[6]uril binds a variety of anionic guest molecules in water. We discuss how and why the anions are bound based on data obtained using NMR spectroscopy, mass spectrometry, isothermal titration...... calorimetry (ITC), computational calculations and single crystal X-ray crystallography....

  19. Isothiouronium Salts Based on Anthracene and Pyrene as Anion Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Quynh Pham Bao; Kim, Taek Hyeon [Chonnam National Univ., Gwangju (Korea, Republic of)

    2010-03-15

    In summary, we prepared anthracene-bisisothiouronium and pyrene-isothiouronium salts as anion chemosensors, which showed significant fluorescence enhancement upon the addition of fluoride, acetate and dihydrogen phosphate, even in an aqueous medium. Due to the isomerism that occurred, the two isomers of the anthracene-bisisothiouronium salt bound the fluoride anion in equilibrium, while the two isomers of the pyrene-isothiouronium salt bound the fluoride anion in parallel. Organic sensors have attracted much attention due to their many possible applications in analytical and biomedical research. Therefore, a variety of synthetic receptors for anions have been reported. Among them, thiourea receptors have been thoroughly exploited in the field of molecular recognition, due to their binding of anions through hydrogen bonding. The use of isothiouronium groups has not been explored very much in the area of anion binding. Such groups can enhance the acidity of the NH moieties, thereby functioning as a better binder compared to the thiourea group. However, in some cases, the investigation of the anion sensing properties of isothiouronium receptors was complicated by the presence of isomerism. In a previous report, the isomerism of anthracene-isothiouronium salts was detected at room temperature. Herein, we wish to report the isomerism of different isothiouronium structures, viz. anthracene-bisisothiouronium and pyrene-isothiouronium salts. The anion sensing properties of these structures was also examined.

  20. Anion binding by biotin[6]uril in water

    DEFF Research Database (Denmark)

    Lisbjerg, Micke; Nielsen, Bjarne Enrico; Milhøj, Birgitte Olai;

    2015-01-01

    In this contribution we show that the newly discovered 6 + 6 biotin-formaldehyde macrocycle Biotin[6]uril binds a variety of anionic guest molecules in water. We discuss how and why the anions are bound based on data obtained using NMR spectroscopy, mass spectrometry, isothermal titration...

  1. Diffuse neutron scattering from anion-excess strontium chloride

    DEFF Research Database (Denmark)

    Goff, J.P.; Clausen, K.N.; Fåk, B.;

    1992-01-01

    The defect structure and diffusional processes have been studied in the anion-excess fluorite (Sr, Y)Cl2.03 by diffuse neutron scattering techniques. Static cuboctahedral clusters found at ambient temperature break up at temperatures below 1050 K, where the anion disorder is highly dynamic. The...

  2. A colorimetric tetrathiafulvalene-calix 4 pyrrole anion sensor

    DEFF Research Database (Denmark)

    Nielsen, K. A.

    2012-01-01

    The interaction and colorimetric sensing properties of a tetrathiafulvalene substituted calix[4]pyrrole sensor with anions were investigated using H-1 NMR and absorption spectroscopic techniques. Visual color changes were observed upon addition of different anions (Cl-, Br-, CN-, and AcO-) to a s...

  3. Triflyloxy-substituted carboranes as useful weakly coordinating anions.

    Science.gov (United States)

    Press, Loren P; McCulloch, Billy J; Gu, Weixing; Chen, Chun-Hsing; Foxman, Bruce M; Ozerov, Oleg V

    2015-09-25

    New carborane anions carrying one or three triflyloxy substituents are described. The mono-triflyloxy substituted carborane can be halogenated to give pentabromo and decachloro derivatives with preservation of the B-OTf linkage. The use of [HCB11Cl10OTf](-) as a weakly coordinating anion is demonstrated. PMID:26251850

  4. Protonation Reaction of Benzonitrile Radical Anion and Absorption of Product

    DEFF Research Database (Denmark)

    Holcman, Jerzy; Sehested, Knud

    1975-01-01

    The rate constant for the protonation of benzonitrile radical anions formed in pulse radiolysis of aqueous benzonitrile solutions is (3.5 ± 0.5)× 1010 dm3 mol–1 s–1. A new 270 nm absorption band is attributed to the protonated benzonitrile anion. The pK of the protonation reaction is determined to...

  5. Extraction of monoclonal antibodies (IgG1) using anionic and anionic/nonionic reverse micelles.

    Science.gov (United States)

    George, Daliya A; Stuckey, David C

    2010-01-01

    Purification schemes for antibody production based on affinity chromatography are trying to keep pace with increases in cell culture expression levels and many current research initiatives are focused on finding alternatives to chromatography for the purification of Monoclonal antibodies (MAbs). In this article, we have investigated an alternative separation technique based on liquid-liquid extraction called the reverse micellar extraction. We extracted MAb (IgG1) using reverse micelles of an anionic surfactant, sodium bis 2-ethyl-hexyl sulfosuccinate (AOT) and a combination of anionic (AOT) and nonionic surfactants (Brij-30, Tween-85, Span-85) using isooctane as the solvent system. The extraction efficiency of IgG1 was studied by varying parameters, such as pH of the aqueous phase, cation concentration, and type and surfactant concentration. Using the AOT/Isooctane reverse micellar system, we could achieve good overall extraction of IgG1 (between 80 and 90%), but only 30% of the bioactivity of IgG1 could be recovered at the end of the extraction by using its binding to affinity chromatography columns as a surrogate measure of activity. As anionic surfactants were suspected as being one of the reasons for the reduced activity, we decided to combine a nonionic surfactant with an anionic surfactant and then study its effect on the extraction efficiency and bioactivity. The best results were obtained using an AOT/Brij-30/Isooctane reverse micellar system, which gave an overall extraction above 90 and 59% overall activity recovery. An AOT/Tween-85/Isooctane reverse micellar system gave an overall extraction of between 75 and 80% and overall activity recovery of around 40-45%. The results showed that the activity recovery of IgG1 can be significantly enhanced using different surfactant combination systems, and if the recovery of IgG1 can be further enhanced, the technique shows considerable promise for the downstream purification of MAbs. PMID:20665658

  6. ARE MODELS OF ANION HYDRATION OVERBOUND ? THE SOLVATION OF THE ELECTRON AND CHLORIDE ANION COMPARED

    OpenAIRE

    Sprik, M.

    1991-01-01

    By means of a fully polarizable model for the chloride ion-water interaction we show that the modelling of anion solvation suffers from a similar inconsistency as the current electron-solvent potentials. Either the bulk hydration enthalpies are correct with the first hydration shell overbound, or the potential is adapted to describe the local environment of the solute at the expense of a major loss of solvation enthalpy. It is argued that boundary effects in the simulation are at least partly...

  7. Coumarin amide derivatives as fluorescence chemosensors for cyanide anions

    International Nuclear Information System (INIS)

    Four coumarin amide derivatives with 4-methyl coumarin or pyrene as terminal group have been synthesized. Their photophysical properties and recognition properties for cyanide anions have been examined. The results indicate that the compounds can recognize cyanide anions with obvious absorption and fluorescence spectra change, at the same time, obvious color and fluorescence change can be observed by naked eye. The in situ hydrogen nuclear magnetic resonance spectra and photophysical properties change confirm that Michael additions between the chemosensors and cyanide anions take place at the 4-position of coumarin. - Highlights: • Four coumarin amide derivatives with 4-methyl coumarin or pyrene as terminal group were synthesized. • The compounds can recognize cyanide anions with obvious absorption and fluorescence spectra change. • Michael additions between the chemosensors and cyanide anions take place at the 4-position of coumarin

  8. K4[Fe(CN)6] immobilized anion sensitive protonated amine functionalized polysilsesquioxane films for ultra-low electrochemical detection of dsDNA.

    Science.gov (United States)

    Silambarasan, Krishnamoorthy; Narendra Kumar, Alam Venugopal; Joseph, James

    2016-03-14

    Charge transport in polymeric films bound by redox reagents is a topic of current interest. The dynamics of electroinactive ions across the interface is studied by immobilizing ferrocyanide anion in a polysilsesquioxanes (PSQs) modified electrode. Redox reagents can stay in the polymeric film by either physical forces or electrostatic binding. The present work describes the immobilization of ferro/ferricyanide redox couples in PSQ films possessing protonated amine functional groups by electrostatic interactions. Charge transport in [Fe(CN)6](4-)-PSQs film was found to be anion dependent, and its formal potential value varied with the relative hydrophilic or hydrophobic nature of the anion used in the supporting electrolyte, unlike the observed dependence on solution cation for electrodes modified with metal hexacyanoferrates (Prussian Blue analogues). The [Fe(CN)6](4-) bound PSQs films were extensively characterized by varying different supporting electrolytes anions using cyclic voltammetry. The redox peak currents were linearly proportional to the square root of the scan rate, implying that the transport of charge carriers is accompanied with redox ion diffusion and electron hopping in a confined space. dsDNA molecules were found to interact with this polymer matrix through anionic phosphate groups. Both voltammetry and A.C. impedance spectroscopy studies revealed that these interactions could be exploited for the determination of ultra-low level (0.5 attomolar) of dsDNA present in aqueous solution. PMID:26898169

  9. The Drosophila Anion Exchanger (DAE lacks a detectable interaction with the spectrin cytoskeleton

    Directory of Open Access Journals (Sweden)

    Base Christine

    2010-06-01

    Full Text Available Abstract Background Current models suggest that the spectrin cytoskeleton stabilizes interacting ion transport proteins at the plasma membrane. The human erythrocyte anion exchanger (AE1 was the first membrane transport protein found to be associated with the spectrin cytoskeleton. Here we evaluated a conserved anion exchanger from Drosophila (DAE as a marker for studies of the downstream effects of spectrin cytoskeleton mutations. Results Sequence comparisons established that DAE belongs to the SLC4A1-3 subfamily of anion exchangers that includes human AE1. Striking sequence conservation was observed in the C-terminal membrane transport domain and parts of the N-terminal cytoplasmic domain, but not in the proposed ankyrin-binding site. Using an antibody raised against DAE and a recombinant transgene expressed in Drosophila S2 cells DAE was shown to be a 136 kd plasma membrane protein. A major site of expression was found in the stomach acid-secreting region of the larval midgut. DAE codistributed with an infolded subcompartment of the basal plasma membrane of interstitial cells. However, spectrin did not codistribute with DAE at this site or in anterior midgut cells that abundantly expressed both spectrin and DAE. Ubiquitous knockdown of DAE with dsRNA eliminated antibody staining and was lethal, indicating that DAE is an essential gene product in Drosophila. Conclusions Based on the lack of colocalization and the lack of sequence conservation at the ankyrin-binding site, it appears that the well-characterized interaction between AE1 and the spectrin cytoskeleton in erythrocytes is not conserved in Drosophila. The results establish a pattern in which most of the known interactions between the spectrin cytoskeleton and the plasma membrane in mammals do not appear to be conserved in Drosophila.

  10. Study of high-anionic conducting sulfonated microporous membranes for zinc-air electrochemical cells

    International Nuclear Information System (INIS)

    High-performance electrochemical membranes have been in great demand due to the rapid market growth in the portable power source devices. The electrochemical characteristics of high-anionic conducting membrane separators were studied in this report using microporous membranes with different sulfonation degrees obtained by changing the sulfonation reaction time. The degree of sulfonation treatment and the effects on the membrane separators were carefully investigated. The room temperature anionic conductivity of the membranes was improved by 132% to 3.52 x 10-2 S cm-1 when the sulfonation treatment time was 128 h. It was about 1.52 x 10-2 S cm-1 for the unsulfonated membranes. The anionic transport number in 1 M KOH aqueous solution was also improved to 0.89 from 0.79. The characteristic properties of these membrane separators were studied by infrared spectroscopy (IR), elemental analysis (EA), X-ray diffraction (XRD), scanning electron microscopy (SEM), AC impedance, contact angle measuring system and stress-strain tests. In addition, the solid-state zinc-air cells assembled from the sulfonated membrane separators showed enhanced battery power density of 38 mW cm-2 while the discharge current density was higher at 45 mA cm-2. The battery power density was around 20 mW cm-2 and the discharge current density was 25 mA cm-2 for the unsulfonated samples. Therefore, the sulfonated microporous membranes could be tailored for the different electrochemical cell applications

  11. Ectopic expression of the erythrocyte band 3 anion exchange protein, using a new avian retrovirus vector

    DEFF Research Database (Denmark)

    Fuerstenberg, S; Beug, H; Introna, M;

    1990-01-01

    A retrovirus vector was constructed from the genome of avian erythroblastosis virus ES4. The v-erbA sequences of avian erythroblastosis virus were replaced by those coding for neomycin phosphotransferase, creating a gag-neo fusion protein which provides G418 resistance as a selectable marker. The...... exchange protein has been expressed from the vector in both chicken embryo fibroblasts and QT6 cells and appears to function as an active, plasma membrane-based anion transporter. The ectopic expression of band 3 protein provides a visual marker for vector function in these cells....

  12. Presence of monovalent oxygen anions in oxides demonstrated using X-ray photoelectron spectra

    Energy Technology Data Exchange (ETDEWEB)

    Wu, L. Q.; Li, Z. Z.; Tang, G. D., E-mail: tanggd@mail.hebtu.edu.cn; Qi, W. H.; Xue, L. C.; Ding, L. L.; Ge, X. S. [Hebei Advanced Thin Film Laboratory, Department of Physics, Hebei Normal University, Shijiazhuang 050024 (China); Li, S. Q. [Hebei Advanced Thin Film Laboratory, Department of Physics, Hebei Normal University, Shijiazhuang 050024 (China); School of Sciences, Hebei University of Science and Technology, Shijiazhuang 050018 (China); Li, Y. C. [No. 46 Research Institute of China Electronics Technology Group Corporation, Tianjin 300220 (China)

    2016-01-11

    The oxygen vacancy model has been used to explain the magnetic and electrical transport properties of dilute magnetic semiconductors and resistive switching. In particular, some authors have claimed that they found a symmetric peak corresponding to the oxygen vacancies in O1s photoelectron spectra. In this paper, using X-ray photoelectron spectra with argon ion etching, it is shown that this symmetric peak may also be interpreted as being related to O{sup 1−} anions, rather than to oxygen vacancies.

  13. An outwardly rectifying anionic background current in atrial myocytes from the human heart

    OpenAIRE

    Li, H.; Zhang, H.; Hancox, J C; Kozlowski, R. Z.

    2007-01-01

    This report describes a hitherto unreported anionic background current from human atrial cardiomyocytes. Under whole-cell patch-clamp with anion-selective conditions, an outwardly rectifying anion current (I ANION) was observed, which was larger with iodide than nitrate, and with nitrate than chloride as charge carrier. In contrast with a previously identified background anionic current from small mammal cardiomyocytes, I ANION was not augmented by the pyrethroid tefluthrin (10 μM); neither w...

  14. Designing New Electrolytes for Lithium Ion Batteries Using Superhalogen Anions

    CERN Document Server

    Srivastava, Ambrish Kumar

    2016-01-01

    The electrolytes used in Lithium Ion Batteries (LIBs) such as LiBF4, LiPF6 etc. are Li-salts of some complex anions, BF4-, PF6- etc. The investigation shows that the vertical detachment energy (VDE) of these anions exceeds to that of halogen, and therefore they behave as superhalogen anions. Consequently, it might be possible to design new electrolytic salts using other superhalogen anions. We have explored this possibility using Li-salts of various superhalogen anions such as BO2-, AlH4-, TiH5- and VH6- as well as hyperhalogen anions, BH4-y(BH4)y-(y = 1 to 4). Our density functional calculations show that Li-salts of these complex anions possess similar characteristics as those of electrolytic salts in LIBs. Note that they all are halogen free and hence, non-toxic and safer than LiBF4, LiPF6 etc. In particular, LiB4H13 and LiB5H16 are two potential candidates for electrolytic salt due to their smaller Li-dissociation energy ({\\Delta}E) than those of LiBF4, LiPF6 etc. We have also noticed that {\\Delta}E of Li...

  15. Interaction of saposin D with membranes: effect of anionic phospholipids and sphingolipids.

    Science.gov (United States)

    Ciaffoni, Fiorella; Tatti, Massimo; Salvioli, Rosa; Vaccaro, Anna Maria

    2003-08-01

    Saposin (Sap) D is an endolysosomal protein that, together with three other similar proteins, Sap A, Sap B and Sap C, is involved in the degradation of sphingolipids and, possibly, in the solubilization and transport of gangliosides. We found that Sap D is able to destabilize and disrupt membranes containing each of the three anionic phospholipids most abundant in the acidic endolysosomal compartment, namely lysobisphosphatidic acid (LBPA), phosphatidylinositol (PI) and phosphatidylserine (PS). The breakdown of the membranes, which occurs when the Sap D concentration on the lipid surface reaches a critical value, is a slow process that gives rise to small particles. The Sap D-particle complexes formed in an acidic milieu can be dissociated by an increase in pH, suggesting a dynamic association of Sap D with membranes. The presence of anionic phospholipids is required also for the Sap D-induced perturbation and solubilization of membranes containing a neutral sphingolipid such as ceramide or a ganglioside such as G(M1). At appropriate Sap D concentrations Cer and G(M1) are solubilized as constituents of small phospholipid particles. Our findings imply that most functions of Sap D are dependent on its interaction with anionic phospholipids, which mediate the Sap D effect on other components of the membrane such as sphingolipids. On consideration of the properties of Sap D we propose that Sap D might have a role in the definition of the structure and function of membranes, such as the intra-endolysosomal membranes, that are rich in anionic phospholipids. PMID:12733985

  16. Antimicrobial Ionic Liquids with Fumarate Anion

    Directory of Open Access Journals (Sweden)

    Biyan He

    2013-01-01

    Full Text Available The shortage of new antimicrobial drugs and increasing resistance of microbe to antimicrobial agents have been of some concern. The formulation studies of new antibacterial and antifungal agents have been an active research field. Ionic liquids are known as designed liquids with controllable physical/chemical/biological properties and specific functions, which have been attracting considerable interest over recent years. However, no attention has been made towards the preparation of ionic liquids with antimicrobial activities. In this paper, a new class of ionic liquids (ILs with fumarate anion was synthesized by neutralization of aqueous 1-butyl-3-methylimidazolium hydroxide with equimolar monoester fumarate and characterized using NMR and thermal gravimetric analysis. The ILs are soluble in water and polar organic solvents and also soluble in the common ILs. The antimicrobial activities of the ILs are more active than commercially available potassium sorbate and are greatly affected by the alkyl chain length. The significant antimicrobial properties observed in this research suggest that the ILs may have potential applications in the modern biotechnology.

  17. Photoelectron spectroscopic study of the ethyl cyanoacrylate anion

    Science.gov (United States)

    Zhang, Xinxing; Tang, Xin; Bowen, Kit

    2013-09-01

    Anion photoelectron spectroscopy and density functional theory have been utilized to study the parent, ethyl cyanoacrylate molecular anion, ECA-. The measured electron affinity (0.9 ± 0.2 eV), vertical detachment energy (1.3 ± 0.1 eV), and anion-to-triplet neutral, photodetachment transition energies (4.0 ± 0.1 eV and 4.5 ± 0.1 eV) all compare well with their calculated values. The relatively high electron affinity of the ECA monomer is responsible for the fact that its “anionic” polymerization mechanism proceeds even with weak nucleophiles, such as water.

  18. Simultaneous determination of inorganic and organic anions by ion chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yang Soon; Joe, Ki Soo; Han, Sun Ho; Park, Soon Dal; Choi, Kwang Soon

    1999-06-01

    Four methods were investigated for the simultaneous determination of several inorganic and organic anions in aqueous solution by ion chromatography. The first is two columns coupled system. The second is the gradient elution system with an anion exchange column. The third is the system with a mixed-mode stationary phase. The fourth is the system with an anion exchange column and the eluant of low conductivity without ion suppressor. The advantages and disadvantages of individual systems were discussed. The suitable methods were proposed for the application to the samples of the nuclear power industry and the environment. (author)

  19. Energy and structure of bonds in the interaction of organic anions with layered double hydroxide nanosheets: A molecular dynamics study

    OpenAIRE

    Tsukanov, A.A.; S.G. Psakhie

    2016-01-01

    The application of hybrid and hierarchical nanomaterials based on layered hydroxides and oxyhydroxides of metals is a swiftly progressing field in biomedicine. Layered double hydroxides (LDH) possess a large specific surface area, significant surface electric charge and biocompatibility. Their physical and structural properties enable them to adsorb various kinds of anionic species and to transport them into cells. However, possible side effects resulting from the interaction of LDH with anio...

  20. Fluoride Induces a Volume Reduction in CA1 Hippocampal Slices Via MAP Kinase Pathway Through Volume Regulated Anion Channels

    OpenAIRE

    Lee, Jaekwang; Han, Young-Eun; Favorov, Oleg; Tommerdahl, Mark; Whitsel, Barry; Lee, C. Justin

    2016-01-01

    Regulation of cell volume is an important aspect of cellular homeostasis during neural activity. This volume regulation is thought to be mediated by activation of specific transporters, aquaporin, and volume regulated anion channels (VRAC). In cultured astrocytes, it was reported that swelling-induced mitogen-activated protein (MAP) kinase activation is required to open VRAC, which are thought to be important in regulatory volume decrease and in the response of CNS to trauma and excitotoxicit...

  1. Unmeasured anions and mortality in critically ill patients in 2016.

    Science.gov (United States)

    Kotake, Yoshifumi

    2016-01-01

    The presence of acid-base disturbances, especially metabolic acidosis may negatively affect the outcome of critically ill patients. Lactic acidosis is the most frequent etiology and has largest impact on the prognosis. Since lactate measurement might not have always been available at bedside, it had been regarded as one of the unmeasured anions. Therefore, anion gap and strong ion gap has been used to as a surrogate of lactate concentration. From this perspective, the relationship between either anion gap or strong ion gap and mortality has been explored. Then, lactate became routinely measurable at bedside and the direct comparison between directly measured lactate and these surrogate parameters can be possible. Currently available evidence suggests that directly measured lactate has larger prognostic ability for mortality than albumin-corrected anion gap and strong ion gap without lactate. In this commentary, the rationale and possible clinical implications of these findings are discussed. PMID:27429758

  2. Fluorinated and trifluoromethylated CB11 carborane anions and radicals

    Czech Academy of Sciences Publication Activity Database

    Higelin, Alexander; Šembera, Filip; Tamadon, F.; Wahab, Abdul; Janoušek, Zbyněk; Ludvík, Jiří; Klíma, Jiří; Crespo, R.; Piqueras, M. C.; Michl, Josef

    San Francisco: American Chemical Society, 2014. 37FLUO. [ACS National Meeting & Exposition /248./. 10.08.2014-14.08.2014, San Francisco] Institutional support: RVO:61388963 Keywords : carborane anions Subject RIV: CC - Organic Chemistry

  3. Adsorption of inorganic anionic contaminants on surfactant modified minerals

    Directory of Open Access Journals (Sweden)

    MAGDALENA TOMASEVIC-CANOVIC

    2003-11-01

    Full Text Available Organo-mineral complexes were obtained by treatment of aluminosilicate minerals (zeolite, bentonite and diatomaceous earth with a primary amine (oleylamine and an alkyl ammonium salt (stearyldimethylbenzyl ammonium chloride. The modification of the zeolite surface was carried out in two steps. The first step was treatment of the zeolite with 2 M HCl. This acid treatment of the zeolite increased its affinity for neutral molecules such as surface-active amines. The second step of the modification was the adsorption of oleylamine on the acid treated zeolite. Four types of organo-mineral complexes were prepared and their anion adsorption properties were compared to those of organo-zeolite. The adsorption of sulphate, bichromate and dihydrogenphosphate anions on the organo-mineral complexes was investigated. The anion adsorption measurements showed that the most efficient adsorbent for anion water pollutants was the primary amine modified H+-form zeolite.

  4. Metal ion separations using hydrophobic anions: Aspects of ligand design

    International Nuclear Information System (INIS)

    Metal ion extraction using hydrophobic anions has been investigated by several researchers for remediation of Cs-137 and Sr-90 in nuclear waste. The rich derivative chemistry of the cobalt bis-dicarbollide anion makes it amendable to systematic studies of the relative importance of anion structure, solvent, and synergists on the extraction selectivity and efficiency. Halogenation or alkylation of cobalt dicarbollide strongly influences the anion's solubility and stability but has little effect on extraction properties. Alkali metal selectivity depends primarily on solvent, while alkaline earth selectivity is driven by the concentration and molecular weight of polyethylene glycol synergists. Additional aspects of ligand design, including a simple extraction and recovery cycle based on redox-active metal centers, will be discussed

  5. Adsorption of anionic dyes on ammonium-functionalized MCM-41

    International Nuclear Information System (INIS)

    Investigations were conducted in a batch reactor system to study the adsorption behavior of four anionic dyes (Methyl orange (MO), Orange IV (OIV), Reactive brilliant red X-3B (X-3B), and Acid fuchsine (AF)) on ammonium-functionalized MCM-41 (NH3+-MCM-41) from aqueous medium by varying the parameters such as contact time, initial dye concentration, pH and competitive anions. Dye adsorption was broadly independent of initial dye concentration. The intraparticle diffusion model was the best in describing the adsorption kinetics for the four anionic dyes on NH3+-MCM-41. The adsorption data for the four dyes were well fitted with the Langmuir model. The electrostatic interaction was considered to be the main mechanism for the dye adsorption. Finally, it was observed that the anion of soft acid inhibited the adsorption capacity significantly

  6. Reaction of tungsten anion clusters with molecular and atomic nitrogen

    OpenAIRE

    Kim, Young Dok; Stolcic, Davor; Fischer, Matthias; Ganteför, Gerd

    2003-01-01

    Ultraviolet photoelectron spectra for WnN-2 (n=1 8) clusters produced by addition of atomic and molecular nitrogen on W anion clusters are presented. Evidence is provided that molecular chemisorption of N2 is more stable than the dissociative one on tungsten anion clusters consisting of eight atoms or less, which is completely different from the results on tungsten bulk surfaces. A general tendency toward molecular chemisorption for small clusters can be explained by reduced charge transfer f...

  7. GAS-GRAIN MODELS FOR INTERSTELLAR ANION CHEMISTRY

    International Nuclear Information System (INIS)

    Long-chain hydrocarbon anions CnH– (n = 4, 6, 8) have recently been found to be abundant in a variety of interstellar clouds. In order to explain their large abundances in the denser (prestellar/protostellar) environments, new chemical models are constructed that include gas-grain interactions. Models including accretion of gas-phase species onto dust grains and cosmic-ray-induced desorption of atoms are able to reproduce the observed anion-to-neutral ratios, as well as the absolute abundances of anionic and neutral carbon chains, with a reasonable degree of accuracy. Due to their destructive effects, the depletion of oxygen atoms onto dust results in substantially greater polyyne and anion abundances in high-density gas (with nH2∼>105 cm–3). The large abundances of carbon-chain-bearing species observed in the envelopes of protostars such as L1527 can thus be explained without the need for warm carbon-chain chemistry. The C6H– anion-to-neutral ratio is found to be most sensitive to the atomic O and H abundances and the electron density. Therefore, as a core evolves, falling atomic abundances and rising electron densities are found to result in increasing anion-to-neutral ratios. Inclusion of cosmic-ray desorption of atoms in high-density models delays freeze-out, which results in a more temporally stable anion-to-neutral ratio, in better agreement with observations. Our models include reactions between oxygen atoms and carbon-chain anions to produce carbon-chain-oxide species C6O, C7O, HC6O, and HC7O, the abundances of which depend on the assumed branching ratios for associative electron detachment.

  8. GAS-GRAIN MODELS FOR INTERSTELLAR ANION CHEMISTRY

    Energy Technology Data Exchange (ETDEWEB)

    Cordiner, M. A. [Also at Institute for Astrophysics and Computational Sciences, Catholic University of America, Washington, DC 20064 (United States); Charnley, S. B., E-mail: martin.cordiner@nasa.gov [Astrochemistry Laboratory and Goddard Center for Astrobiology, Mailstop 691, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20770 (United States)

    2012-04-20

    Long-chain hydrocarbon anions C{sub n}H{sup -} (n = 4, 6, 8) have recently been found to be abundant in a variety of interstellar clouds. In order to explain their large abundances in the denser (prestellar/protostellar) environments, new chemical models are constructed that include gas-grain interactions. Models including accretion of gas-phase species onto dust grains and cosmic-ray-induced desorption of atoms are able to reproduce the observed anion-to-neutral ratios, as well as the absolute abundances of anionic and neutral carbon chains, with a reasonable degree of accuracy. Due to their destructive effects, the depletion of oxygen atoms onto dust results in substantially greater polyyne and anion abundances in high-density gas (with n{sub H{sub 2}}{approx}>10{sup 5} cm{sup -3}). The large abundances of carbon-chain-bearing species observed in the envelopes of protostars such as L1527 can thus be explained without the need for warm carbon-chain chemistry. The C{sub 6}H{sup -} anion-to-neutral ratio is found to be most sensitive to the atomic O and H abundances and the electron density. Therefore, as a core evolves, falling atomic abundances and rising electron densities are found to result in increasing anion-to-neutral ratios. Inclusion of cosmic-ray desorption of atoms in high-density models delays freeze-out, which results in a more temporally stable anion-to-neutral ratio, in better agreement with observations. Our models include reactions between oxygen atoms and carbon-chain anions to produce carbon-chain-oxide species C{sub 6}O, C{sub 7}O, HC{sub 6}O, and HC{sub 7}O, the abundances of which depend on the assumed branching ratios for associative electron detachment.

  9. Gas-Grain Models for Interstellar Anion Chemistry

    Science.gov (United States)

    Cordiner, M. A.; Charnely, S. B.

    2012-01-01

    Long-chain hydrocarbon anions C(sub n) H(-) (n = 4, 6, 8) have recently been found to be abundant in a variety of interstellar clouds. In order to explain their large abundances in the denser (prestellar/protostellar) environments, new chemical models are constructed that include gas-grain interactions. Models including accretion of gas-phase species onto dust grains and cosmic-ray-induced desorption of atoms are able to reproduce the observed anion-to-neutral ratios, as well as the absolute abundances of anionic and neutral carbon chains, with a reasonable degree of accuracy. Due to their destructive effects, the depletion of oxygen atoms onto dust results in substantially greater polyyne and anion abundances in high-density gas (with n(sub H2) approx > / cubic cm). The large abundances of carbon-chain-bearing species observed in the envelopes of protostars such as L1527 can thus be explained without the need for warm carbon-chain chemistry. The C6H(-) anion-to-neutral ratio is found to be most sensitive to the atomic O and H abundances and the electron density. Therefore, as a core evolves, falling atomic abundances and rising electron densities are found to result in increasing anion-to-neutral ratios. Inclusion of cosmic-ray desorption of atoms in high-density models delays freeze-out, which results in a more temporally stable anion-to-neutral ratio, in better agreement with observations. Our models include reactions between oxygen atoms and carbon-chain anions to produce carbon-chain-oxide species C6O, C7O, HC6O, and HC7O, the abundances of which depend on the assumed branching ratios for associative electron detachment

  10. Core-modified octaphyrins: Syntheses and anion-binding properties

    Indian Academy of Sciences (India)

    Rajneesh Misra; Venkataramanarao G Anand; Harapriya Rath; Tavarekere K Chandrashekar

    2005-03-01

    In this paper, a brief review of the syntheses, characterization and anion-binding properties of core-modified octaphyrins is presented. It has been shown that the core-modified octaphyrins exhibit aromaticity both in solution and in solid state, confirming the validity of the (4 + 2) Huckel rule for larger -electron systems. Solid-state binding characteristics of TFA anions of two core-modified octaphyrins are also described.

  11. Synthesis and Binding Properties of Two New Artificial Anion Receptors

    Institute of Scientific and Technical Information of China (English)

    ZENG Zhen-Ya; HUANG Yan-Yan; HU Ling; WANG Fa-Jun; HE Yong-Bing

    2003-01-01

    @@ The development of anion receptor has attracted increasing interest in supramolecular chemistry, due to poten tial applications in clinical diagnosis, environmental monitoring and biological process. [1] In comparison with thelarge variety of ligands that have been described for cations, [2] the development of selective artificial receptors foranion is still very limited. [3] Two new neutral anion receptors (1 and 2) containing thiourea and amide groups weresynthesized as shown in Scheme 1.

  12. Membrane vesicles: A simplified system for studying auxin transport

    Energy Technology Data Exchange (ETDEWEB)

    Goldsmith, M.H.M.

    1989-01-01

    Indoleacetic acid (IAA), the auxin responsible for regulation of growth, is transported polarly in plants. Several different models have been suggested to account for IAA transport by cells and its accumulation by membrane vesicles. One model sees diffusion of IAA driven by a pH gradient. The anion of a lipophilic weak acid like IAA or butyrate accumulates in an alkaline compartment in accord with the size of the pH gradient The accumulation of IAA may be diminished by the permeability of its lipophilic anion. This anion leak may be blocked by NPA. With anion efflux blocked, a gradient of two pH units would support an IAA accumulation of less than 50-fold at equilibrium (2) Another model sees diffusion of IAA in parallel with a saturable symport (IAA[sup [minus

  13. Sources of anions in aerosols in northeast Greenland during late winter

    DEFF Research Database (Denmark)

    Lauridsen, Marlene Fenger; Sørensen, Lise Lotte; Kristensen, Kasper;

    2013-01-01

    The knowledge of climate effects of atmospheric aerosols is associated with large uncertainty, and a better understanding of their physical and chemical properties is needed, especially in the Arctic environment. The objective of the present study is to improve our understanding of the processes...... affecting the composition of aerosols in the high Arctic. Therefore size-segregated aerosols were sampled at a high Arctic site, Station Nord (Northeast Greenland), in March 2009 using a Micro Orifice Uniform Deposit Impactor. The aerosol samples were extracted in order to analyse three water-soluble anions...... ), respectively. The aerosols in late winter/early spring, after polar sunrise, are found to be a mixture of long-range transported and regional to local originating aerosols. Fine particles, smaller than 1 μm, containing SO2−4 , Cl− and NO− 3 , are hypothesized to originate from long-range transport, where SO2...

  14. Diffusion of hydrogen, hydrogen sulfide and large molecular weight anions in bentonite

    International Nuclear Information System (INIS)

    The diffusivities of HS- and H2 have been determined from profile analysis and steady state transport experiments. The diffusivity of HS- was found to be 9x10-12 and 4x10xsec1 in MX-80 and Erbsloeh bentonite respectively. The results are in fair agreement with the results earlier obtained for Cl- and I-. The H2 diffusivity calculated from steady state transport was found to be surprisingly low (3.6x10-12m2xsec-1). Various heavy anions with molecular weights 290-30x103 were found to migrate through MX-80 bentonite with diffusivities in the range (2,1-0,75)x10-15m2xsec-1. (Author)

  15. Leveraging material properties in fluorescence anion sensor arrays: a general approach.

    Science.gov (United States)

    Anzenbacher, Pavel; Liu, Yuanli; Palacios, Manuel A; Minami, Tsuyoshi; Wang, Zhuo; Nishiyabu, Ryuhei

    2013-06-24

    As the demand for probes suitable for sensor development increases, investigation of approaches that utilize known successful receptors gains in general importance. This study describes a two-prong approach that can be used as a guide to developing sensors from known receptors. First, the conversion of a simple receptor, calix[4]pyrrole, into a fluorescent probe to establish a ratiometric signal is described. Secondly, the sensors that employ an output from a single ratiometric calix[4]pyrrole probe are fabricated by using poly(ether-urethane) hydrogel copolymers. These hydrogels are designed to absorb, internalize and transport aqueous electrolytes. A sensor array of ten different poly(ether-urethane) matrices with varying comonomer proportions were doped with a single probe and were exposed to eight different anions: acetate, benzoate, fluoride, chloride, phosphate, pyrophosphate, hydrogen sulfide, and cyanide, eight urine samples and anti-inflammatory drugs (NSAIDs). The poly(ether-urethane) matrices comprise different proportions of anion-binding urethane moieties and different hydrophilicity given by the ratio between ethylene glycol ether and butylene glycol ether. This diversity in the hydration behavior provides different environment polarity, in which the recognition and self-assembly processes display enough diverse behavior to allow for unique response of the probe to the analytes. Furthermore, a single probe is shown to recognize eight different aqueous anions and eight urine samples when embedded in ten different polyurethanes in an array that displays 100 % classification accuracy. To demonstrate the potential of the concept for quantitative studies, an estimation of non-steroidal anti-inflammatory drugs ibuprofen and diclofenac in water and in saliva was performed. A limit of detection of 0.1 ppm and a dynamic range of 0.1-0.6 and 0.05-60 ppm was observed, respectively. Given the general difficulty of chemosensors to recognize aqueous anions

  16. Study of the simultaneous complexation of a cation and of an anion using functionalized calixarenes

    International Nuclear Information System (INIS)

    The chemical reprocessing of irradiated nuclear fuels leads to the production of high-level radioactive liquid wastes which contain long-lived toxic radioelements. In the framework of the long-term management of these wastes, important research work is carried out for the separation of these radioelements for their further transmutation or immobilization inside specific matrices. These radioelements are present in acid solutions of fission products in the form of cations (cesium), anions (technetium, selenium) and molecules (iodine). Crown calixarenes have been successfully used for the extraction of cesium thanks to their exceptional selectivities. This work is mainly based on the use of the chelating properties of calixarenes for the extraction of anionic radioelements. Calixarenes functionalized by amino-carbon chains have been selected. The synthesis of amine calix[4]arenes and calix[6]arenes is described and their extractive and ionophoretic properties with respect to radioelements are shown using aqueous selective separation techniques like the liquid-liquid extraction and the supported liquid membrane transport. Technetium and selenium are extracted by amine calixarenes from a 10-2 M aqueous solution of nitric acid. At this acidity, no selenium transport is observed, while technetium transport is efficient: the solution is quasi-totally decontaminated in 6 hours. Molecular iodine is efficiently extracted with a simple organic diluent, the 1,2-nitro-phenyl-hexyl-ether, from a strongly concentrated aqueous solution of nitric acid (HNO3 = 3 M). The transport of iodine becomes faster and more efficient when its concentration in the solution is higher. (J.S.)

  17. Ionic liquids formed with polycyano 1,1,3,3-tetracyanoallyl anions: substituent effects of anions on liquid properties.

    Science.gov (United States)

    Yoshida, Yukihiro; Kondo, Masatoshi; Saito, Gunzi

    2009-07-01

    A series of ionic liquids based on five kinds of polycyano 1,1,3,3-tetracyanoallyl anions with 2-substituents having different electron-withdrawing or -donating abilities were prepared. The influence of the chemical modification on their thermal properties, viscosity, ionic conductivity, ion association, and solvatochromic shifts was characterized and compared with the case of previously reported polycyano anions, N(CN)(2)(-) and C(CN)(3)(-). Among the 1-butyl-3-methylimidazolium (BMI) salts, cyano-substituted (i.e., 1,1,2,3,3-pentacyanoallyl anion) salt has the highest melting point (42 degrees C), possibly indicating the importance of high local symmetry over decreased interionic CN...cation interactions due to the limited electron densities on terminal nitrogens of the anions, predicted by ab initio calculations. In the liquid state, methoxy-substituted (i.e., 2-methoxy-1,1,3,3-tetracyanoallyl anion) salt has the highest fluidity and ionic conductivity, associated with the significant conformational degree of freedom in the methoxy group. Although the ion diffusivity has no definite correlation with the Hammett parameter of the substituents, the introduction of electron-withdrawing cyano or cyanomethyl (i.e., 2-cyanomethyl-1,1,3,3-tetracyanoallyl anion) groups leads to the decrease in the degree of ion association and solvent donor ability, which were manifested in the Walden rule deviation and solvatochromic shift, respectively. PMID:19518062

  18. DISCOVERY OF INTERSTELLAR ANIONS IN CEPHEUS AND AURIGA

    International Nuclear Information System (INIS)

    We report the detection of microwave emission lines from the hydrocarbon anion C6H- and its parent neutral C6H in the star-forming region L1251A (in Cepheus), and the pre-stellar core L1512 (in Auriga). The carbon-chain-bearing species C4H, HC3N, HC5N, HC7N, and C3S are also detected in large abundances. The observations of L1251A constitute the first detections of anions and long-chain polyynes and cyanopolyynes (with more than five carbon atoms) in the Cepheus Flare star-forming region, and the first detection of anions in the vicinity of a protostar outside of the Taurus molecular cloud complex, indicating a possible wider importance for anions in the chemistry of star formation. Rotational excitation temperatures have been derived from the HC3N hyperfine structure lines and are found to be 6.2 K for L1251A and 8.7 K for L1512. The anion-to-neutral ratios are 3.6% and 4.1%, respectively, which are within the range of values previously observed in the interstellar medium, and suggest a relative uniformity in the processes governing anion abundances in different dense interstellar clouds. This research contributes toward the growing body of evidence that carbon chain anions are relatively abundant in interstellar clouds throughout the Galaxy, but especially in the regions of relatively high density and high depletion surrounding pre-stellar cores and young, embedded protostars.

  19. Choroid plexus transport: gene deletion studies

    Directory of Open Access Journals (Sweden)

    Keep Richard F

    2011-11-01

    Full Text Available Abstract This review examines the use of transporter knockout (KO animals to evaluate transporter function at the choroid plexus (the blood-CSF barrier; BCSFB. Compared to the blood-brain barrier, there have been few such studies on choroid plexus (CP function. These have primarily focused on Pept2 (an oligopeptide transporter, ATP-binding cassette (ABC transporters, Oat3 (an organic anion transporter, Svct2 (an ascorbic acid transporter, transthyretin, ion transporters, and ion and water channels. This review focuses on the knowledge gained from such studies, both with respect to specific transporters and in general to the role of the CP and its impact on brain parenchyma. It also discusses the pros and cons of using KO animals in such studies and the technical approaches that can be used.

  20. Silent S-Type Anion Channel Subunit SLAH1 Gates SLAH3 Open for Chloride Root-to-Shoot Translocation.

    Science.gov (United States)

    Cubero-Font, Paloma; Maierhofer, Tobias; Jaslan, Justyna; Rosales, Miguel A; Espartero, Joaquín; Díaz-Rueda, Pablo; Müller, Heike M; Hürter, Anna-Lena; Al-Rasheid, Khaled A S; Marten, Irene; Hedrich, Rainer; Colmenero-Flores, José M; Geiger, Dietmar

    2016-08-22

    Higher plants take up nutrients via the roots and load them into xylem vessels for translocation to the shoot. After uptake, anions have to be channeled toward the root xylem vessels. Thereby, xylem parenchyma and pericycle cells control the anion composition of the root-shoot xylem sap [1-6]. The fact that salt-tolerant genotypes possess lower xylem-sap Cl(-) contents compared to salt-sensitive genotypes [7-10] indicates that membrane transport proteins at the sites of xylem loading contribute to plant salinity tolerance via selective chloride exclusion. However, the molecular mechanism of xylem loading that lies behind the balance between NO3(-) and Cl(-) loading remains largely unknown. Here we identify two root anion channels in Arabidopsis, SLAH1 and SLAH3, that control the shoot NO3(-)/Cl(-) ratio. The AtSLAH1 gene is expressed in the root xylem-pole pericycle, where it co-localizes with AtSLAH3. Under high soil salinity, AtSLAH1 expression markedly declined and the chloride content of the xylem sap in AtSLAH1 loss-of-function mutants was half of the wild-type level only. SLAH3 anion channels are not active per se but require extracellular nitrate and phosphorylation by calcium-dependent kinases (CPKs) [11-13]. When co-expressed in Xenopus oocytes, however, the electrically silent SLAH1 subunit gates SLAH3 open even in the absence of nitrate- and calcium-dependent kinases. Apparently, SLAH1/SLAH3 heteromerization facilitates SLAH3-mediated chloride efflux from pericycle cells into the root xylem vessels. Our results indicate that under salt stress, plants adjust the distribution of NO3(-) and Cl(-) between root and shoot via differential expression and assembly of SLAH1/SLAH3 anion channel subunits. PMID:27397895

  1. Poly-anion production in Penning and RFQ ion traps

    Energy Technology Data Exchange (ETDEWEB)

    Bandelow, Steffi; Martinez, Franklin; Marx, Gerrit; Schweikhard, Lutz [Institute for Physics, Ernst-Moritz-Arndt University, 17487 Greifswald (Germany)

    2014-07-01

    The poly-anion production is being investigated in Penning and linear radio-frequency quadrupole (RFQ) traps at the ClusterTrap setup. The range of anionic charge states produced with the electron-bath technique in a Penning trap is restricted by the upper mass limit of this trap. By installation of a cylindrical Penning trap with a 12-Tesla superconducting magnet, the mass and thus cluster-size range is enhanced by a factor of 20 compared to the previously used hyperbolic 5-Tesla Penning trap. For first experimental tests with the 12-Tesla cylindrical Penning trap, gold cluster mono-anions Au{sup n-1}, n=330-350, have been exposed to an electron bath. As a result, higher negative charge states up to hexa-anionic clusters have been observed for the first time. In a parallel effort, di- and tri-anionic gold clusters have been produced in an RFQ-trap. To this end, an electron beam is guided through the RFQ-trap, which is operated by 2- or 3-state digital driving voltages. In addition, both polyanion-production techniques have been combined by pre-charging clusters in the RFQ-trap, transferring the resulting dianions into the Penning trap and applying the electron-bath technique to produce higher charge states.

  2. Metal-Oxide Film Conversions Involving Large Anions

    Energy Technology Data Exchange (ETDEWEB)

    Pretty, S.; Zhang, X.; Shoesmith, D.W.; Wren, J.C. [The University of Western Ontario, Chemistry Department, 1151 Richmond St., N6A 5B7, London, Ontario (Canada)

    2008-07-01

    The main objective of my research is to establish the mechanism and kinetics of metal-oxide film conversions involving large anions (I{sup -}, Br{sup -}, S{sup 2-}). Within a given group, the anions will provide insight on the effect of anion size on the film conversion, while comparison of Group 6 and Group 7 anions will provide insight on the effect of anion charge. This research has a range of industrial applications, for example, hazardous radioiodine can be immobilized by reaction with Ag to yield AgI. From the perspective of public safety, radioiodine is one of the most important fission products from the uranium fuel because of its large fuel inventory, high volatility, and radiological hazard. Additionally, because of its mobility, the gaseous iodine concentration is a critical parameter for safety assessment and post-accident management. A full kinetic analysis using electrochemical techniques has been performed on the conversion of Ag{sub 2}O to (1) AgI and (2) AgBr. (authors)

  3. REACTIVITY OF ANIONS IN INTERSTELLAR MEDIA: DETECTABILITY AND APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Senent, M. L. [Departamento de Quimica y Fisica Teoricas, Instituto de Estructura de la Materia, IEM-C.S.I.C., Serrano 121, Madrid E-28006 (Spain); Hochlaf, M., E-mail: senent@iem.cfmac.csic.es, E-mail: hochlaf@univ-mlv.fr [Laboratoire de Modelisation et Simulation Multi Echelle, Universite Paris-Est, MSME UMR 8208 CNRS, 5 boulevard Descartes, F-77454 Marne-la-Vallee (France)

    2013-05-01

    We propose a general rule to distinguish between detectable and undetectable astronomical anions. We believe that only few anions live long enough in the interstellar medium and thus can be detected. Our method is based on quantum mechanical calculations capable of describing accurately the evolution of electronic states during chemical processes. The still not fully understood reactivity at low temperatures is discussed considering non-adiabatic effects. The role of excited states has usually been neglected in previous works which basically focused on the ground electronic state for interpretations of experimental observations. Here, we deal with unsaturated carbon chains (e.g., C{sub n} H{sup -}), which show a high density of electronic states close to their corresponding ground electronic states, complex molecular dynamics, and non-adiabatic phenomena. Our general rule shows that it is not sufficient that anions exist in the gas phase (in the laboratory) to be present in media such as astrophysical media, since formation and decomposition reactions of these anions may allow the population of anionic electronic states to autodetach, forming neutrals. For C{sub n} H, reactivity depends strongly on n, where long and short chains behave differently. Formation of linear chains is relevant.

  4. REACTIVITY OF ANIONS IN INTERSTELLAR MEDIA: DETECTABILITY AND APPLICATIONS

    International Nuclear Information System (INIS)

    We propose a general rule to distinguish between detectable and undetectable astronomical anions. We believe that only few anions live long enough in the interstellar medium and thus can be detected. Our method is based on quantum mechanical calculations capable of describing accurately the evolution of electronic states during chemical processes. The still not fully understood reactivity at low temperatures is discussed considering non-adiabatic effects. The role of excited states has usually been neglected in previous works which basically focused on the ground electronic state for interpretations of experimental observations. Here, we deal with unsaturated carbon chains (e.g., Cn H–), which show a high density of electronic states close to their corresponding ground electronic states, complex molecular dynamics, and non-adiabatic phenomena. Our general rule shows that it is not sufficient that anions exist in the gas phase (in the laboratory) to be present in media such as astrophysical media, since formation and decomposition reactions of these anions may allow the population of anionic electronic states to autodetach, forming neutrals. For Cn H, reactivity depends strongly on n, where long and short chains behave differently. Formation of linear chains is relevant.

  5. Determination of inorganic anions in papermaking waters by ion chromatography

    Directory of Open Access Journals (Sweden)

    DARJA ŽARKOVIĆ

    2009-03-01

    Full Text Available A suppressed ion chromatography (IC method for the determination of inorganic anions in process water from paperboard production was developed and validated. Common inorganic anions (Cl-, NO3-, PO43- and SO42- were detected in fresh and process water samples collected from a paperboard production system at 16 characteristic points. It was shown that the use of an IonPac®-AS14 column under isocratic conditions with Na2CO3/NaHCO3 as the eluent and a suppression device proved to be a reliable analytical solution for the separation of the inorganic anions present in papermaking waters. This IC method is quite satisfactory concerning selectivity and sensitivity, and enables the determination of several inorganic anions over a wide concentration range. According to the obtained results, the total amount of analyzed inorganic anions was below 0.1 g/L, i.e., below the critical value which may trigger operational problems in paper production.

  6. Anion adsorption and atomic friction on Au(1 1 1)

    International Nuclear Information System (INIS)

    Highlights: ► Electrochemical lateral force microscopy on Au(1 1 1) in sulphuric and perchloric acid. ► Lateral forces at the atomic scale are sensitive to the adsorption state of anions. ► Friction changes at lower potentials than expected from cyclic voltammograms. ► Friction increases with normal load when sliding on specifically adsorbed anions. ► A dramatic increase in friction occurs upon electrochemical oxidation of the surface. - Abstract: The influence of anion adsorption on friction forces in an electrochemical environment has been studied by means of lateral force microscopy on Au(1 1 1) surfaces. Sensitivity to atomic stick-slip motion allows to reveal sulphate adsorption in ordered layers under the sliding tip at potentials lower than expected from cyclic voltammetry for the open surface. No ordered adsorption is found in lateral force measurements for the weakly adsorbed perchlorate anions. Correspondingly, some increase in friction in the anion adsorption regime is observed for sulphate but none for perchlorate adsorption. Friction increases significantly at the onset of oxidation in both sulphuric and perchloric acid solutions.

  7. Metal-Oxide Film Conversions Involving Large Anions

    International Nuclear Information System (INIS)

    The main objective of my research is to establish the mechanism and kinetics of metal-oxide film conversions involving large anions (I-, Br-, S2-). Within a given group, the anions will provide insight on the effect of anion size on the film conversion, while comparison of Group 6 and Group 7 anions will provide insight on the effect of anion charge. This research has a range of industrial applications, for example, hazardous radioiodine can be immobilized by reaction with Ag to yield AgI. From the perspective of public safety, radioiodine is one of the most important fission products from the uranium fuel because of its large fuel inventory, high volatility, and radiological hazard. Additionally, because of its mobility, the gaseous iodine concentration is a critical parameter for safety assessment and post-accident management. A full kinetic analysis using electrochemical techniques has been performed on the conversion of Ag2O to (1) AgI and (2) AgBr. (authors)

  8. Poly-anion production in Penning and RFQ ion traps

    International Nuclear Information System (INIS)

    The poly-anion production is being investigated in Penning and linear radio-frequency quadrupole (RFQ) traps at the ClusterTrap setup. The range of anionic charge states produced with the electron-bath technique in a Penning trap is restricted by the upper mass limit of this trap. By installation of a cylindrical Penning trap with a 12-Tesla superconducting magnet, the mass and thus cluster-size range is enhanced by a factor of 20 compared to the previously used hyperbolic 5-Tesla Penning trap. For first experimental tests with the 12-Tesla cylindrical Penning trap, gold cluster mono-anions Aun-1, n=330-350, have been exposed to an electron bath. As a result, higher negative charge states up to hexa-anionic clusters have been observed for the first time. In a parallel effort, di- and tri-anionic gold clusters have been produced in an RFQ-trap. To this end, an electron beam is guided through the RFQ-trap, which is operated by 2- or 3-state digital driving voltages. In addition, both polyanion-production techniques have been combined by pre-charging clusters in the RFQ-trap, transferring the resulting dianions into the Penning trap and applying the electron-bath technique to produce higher charge states.

  9. Anion-Dependent Aggregate Formation and Charge Behavior of Colloidal Fullerenes (n-C60)

    Science.gov (United States)

    Mukherjee, B.; Weaver, J. W.

    2009-12-01

    The fate and transport of colloidal fullerenes (n-C60) in the environment are likely to be guided by their electrokinetic and aggregation behavior. In natural water bodies inorganic ions exert significant effects in determining the size and charge of dispersed n-C60. Although the effects of cations on the behavior of n-C60 have been studied extensively; studies on the effect of anions are relatively few and thus were the focus of our investigation. The effects of anions (e.g., Cl- , SO42-) on average aggregate size (DH) and zeta potential (ZP) of n-C60 were found to be absent in presence of monovalent cations (e.g., Na+) over the tested range of pH (3-to-12) and ionic strength (0-to-20 mM). Similar observations were noted in the presence of multivalent cations (e.g., Mg2+) near acidic and neutral pH conditions. However, under alkaline conditions (pH~10) a strong anion-dependent reversal of surface charge was noted. The ZP of n-C60 changed from -65 mV, when dispersed in DI water, to +4 mV and +40 mV in the presence of SO42- and Cl-, respectively in a 10mM salt concentration (i.e., MgCl2 and MgSO4). The corresponding DH of the dispersed n-C60 changed simultaneously from 115 nm, in DI water, to 1450 nm and 225 nm for the MgSO4 and MgCl2 electrolytes. These findings provide a better understanding of interfacial interaction characteristics of n-C60 NPs, and may lead to remediation strategies for n-C60 NPs in the environment.

  10. Anion exchange sorption of molybdate and germanate from salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kislinskaya, G.E.; Denisova, T.I.; Sheka, I.A. (AN Ukrainskoj SSR, Kiev. Inst. Obshchej i Neorganicheskoj Khimii)

    1983-02-01

    A study has been made of the state of Mo(6) and Ge(4) in solutions containing various concentrations (5-300 g/l) of HCl and their sorption with highly-alkaline macroporous anionites (Duolite 101 D, ChFO, AM, AMP) and hydroxides of iron and aluminium, depending on pH value, element concentration and time of solution contact with sorbent. Polymer anions of molybdate with a sorption maximum at pH=1-3 and monomer anions of germanate at pH>8 are found to be the most active forms of molybdenum and germanium, as to their sorption, at their concentrations of 10/sup -6/-10/sup -5/g-atom/l in sodium chloride solutions. Regions of molybdate and germanate effective sorption with anionites and hydroxides of iron and aluminium in electrolyte solutions get narrower, as compared with aqueous solutions, due to competing sorption of a background electrolyte anion.

  11. Organization and function of anionic phospholipids in bacteria.

    Science.gov (United States)

    Lin, Ti-Yu; Weibel, Douglas B

    2016-05-01

    In addition to playing a central role as a permeability barrier for controlling the diffusion of molecules and ions in and out of bacterial cells, phospholipid (PL) membranes regulate the spatial and temporal position and function of membrane proteins that play an essential role in a variety of cellular functions. Based on the very large number of membrane-associated proteins encoded in genomes, an understanding of the role of PLs may be central to understanding bacterial cell biology. This area of microbiology has received considerable attention over the past two decades, and the local enrichment of anionic PLs has emerged as a candidate mechanism for biomolecular organization in bacterial cells. In this review, we summarize the current understanding of anionic PLs in bacteria, including their biosynthesis, subcellular localization, and physiological relevance, discuss evidence and mechanisms for enriching anionic PLs in membranes, and conclude with an assessment of future directions for this area of bacterial biochemistry, biophysics, and cell biology. PMID:27026177

  12. Selection of anion exchange resins for boron thermal regeneration systems

    International Nuclear Information System (INIS)

    Boron concentration changes in the reactor coolant are effected using a new development called the boron thermal regeneration system (BTRS). Thermal regeneration refers to the use of ion-exchange resins in either retaining or releasing borate ions as a function of temperature. For the BTRS the equilibrium capacity of commercial and special anion exchange resins was investigated for the degree of cross-linking of anion resins. The equilibrium capacity increases with decreased temperature and depends strongly on the degree of cross-linking having the maximum point at about 7% of DVB. The temperature coefficient of equilibrium capacity of boric acid is also a function of the concentration of external solution and of the cross-linking having a maximum point of around 7% of DVB. Other basic characteristics of anion exchange resin were also investigated. (author)

  13. Determination of arsenate in water by anion selective membrane electrode using polyurethane–silica gel fibrous anion exchanger composite

    International Nuclear Information System (INIS)

    Highlights: • PU–Si gel is new anion exchanger material synthesized and characterized. • This material used as anion exchange membrane is applied for electroanalytical studies. • The method for detection and determination of AsO43− in traces amounts discussed. • The results are also verified from arsenic analyzer. -- Abstract: Polyurethane (PU)–silica (Si gel) based fibrous anion exchanger composites were prepared by solid–gel polymerization of polyurethane in the presence of different amounts of silica gel. The formation of PU–Si gel fibrous anion exchanger composite was characterized by Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA-DTA), scanning electron microscopy (SEM) and elemental analysis. The membrane having a composition of 5:3 (PU:Si gel) shows best results for water content, porosity, thickness and swelling. Our studies show that the present ion selective membrane electrode is selective for arsenic, having detection limit (1 × 10−8 M to 1 × 10−1 M), response time (45 s) and working pH range (5–8). The selectivity coefficient values for interfering ions indicate good selectivity for arsenate (AsO43−) over interfering anions. The accuracy of the detection limit results was compared by PCA-Arsenomat

  14. Gas-grain models for interstellar anion chemistry

    OpenAIRE

    Cordiner, M. A.; Charnley, S. B.

    2012-01-01

    Long-chain hydrocarbon anions CnH- (n=4, 6, 8) have recently been found to be abundant in a variety of interstellar clouds. In order to explain their large abundances in the denser (prestellar/protostellar) environments, new chemical models are constructed that include gas-grain interactions. Models including accretion of gas-phase species onto dust grains and cosmic-ray-induced desorption of atoms are able to reproduce the observed anion-to-neutral ratios, as well as the absolute abundances ...

  15. Electrostatic charge confinement using bulky tetraoctylammonium cation and four anions

    Science.gov (United States)

    Andreeva, Nadezhda A.; Chaban, Vitaly V.

    2016-04-01

    Thanks to large opposite electrostatic charges, cations and anions establish strong ionic bonds. However, applications of ionic systems - electrolytes, gas capture, solubilization, etc. - benefit from weaker non-covalent bonds. The common approaches are addition of cosolvents and delocalization of electron charge density via functionalization of ions. We report fine tuning of closest-approach distances, effective radii, and cation geometry by different anions using the semi-empirical molecular dynamics simulations. We found that long fatty acid chains employed in the tetraalkylammonium cation are largely inefficient and new substituents must be developed. The reported results foster progress of task-specific ionic liquids.

  16. Procedure for reducing hydrogen ion concentration in acidic anion eluate

    International Nuclear Information System (INIS)

    A procedure is suggested for reducing the concentration of hydrogen ions in the acidic anionic eluate formed during the separation of uranium. The procedure involves anex elution, precipitation, filtration, precipitate rinsing, and anex rinsing. The procedure is included in the uranium elution process and requires at least one ion exchanger column and at least one tank in the continuous or discontinuous mode. Sparing the neutralizing agent by reducing the hydrogen ion concentration in the acidic anionic eluate is a major asset of this procedure. (Z.S.). 1 fig

  17. Photoelectron spectroscopy of boron aluminum hydride cluster anions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haopeng; Zhang, Xinxing; Ko, Yeon Jae; Gantefoer, Gerd; Bowen, Kit H., E-mail: kbowen@jhu.edu, E-mail: kiran@mcneese.edu [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Li, Xiang [Center for Space Science and Technology, University of Maryland–Baltimore County, Baltimore, Maryland 21250 (United States); Kiran, Boggavarapu, E-mail: kbowen@jhu.edu, E-mail: kiran@mcneese.edu [Department of Chemistry and Physics, McNeese State University, Lake Charles, Louisiana 70609 (United States); Kandalam, Anil K. [Department of Physics, West Chester University, West Chester, Pennsylvania 19383 (United States)

    2014-04-28

    Boron aluminum hydride clusters are studied through a synergetic combination of anion photoelectron spectroscopy and density functional theory based calculations. Boron aluminum hydride cluster anions, B{sub x}Al{sub y}H{sub z}{sup −}, were generated in a pulsed arc cluster ionization source and identified by time-of-flight mass spectrometry. After mass selection, their photoelectron spectra were measured by a magnetic bottle-type electron energy analyzer. The resultant photoelectron spectra as well as calculations on a selected series of stoichiometries reveal significant geometrical changes upon substitution of aluminum atoms by boron atoms.

  18. Recovery of niobium anions from aqueous solutions by ion flotation

    International Nuclear Information System (INIS)

    In principle the feasibility of recovering niobates (K2NbOF5 and K2NbF7) from aqueous media by ion flotation was established. When using quaternary ammonium bases or amines as the collectors, the optimal conditions lie in the interval pH = 5.0-9.0. The interaction of niobates with cationic surfactants may proceed through an anion-exchange mechanism. The presence of acid in the solution suppresses this interaction, owing to the competition from the anions that are present and owing to binding of the surface-active collectors into a complex. 3 figures

  19. A lanthanide complex for metal encapsulations and anion exchanges.

    Science.gov (United States)

    Sun, Yan-Qiong; Wan, Fang; Li, Xin-Xiong; Lin, Jian; Wu, Tao; Zheng, Shou-Tian; Bu, Xianhui

    2016-08-01

    A cationic lanthanide metalloligand with 3 dangling carboxylate groups on its periphery co-assembles with nitrate into a porous thermochromic solid responsive to both external cations and anions, owing to the presence of exchangeable NO3(-) as well as cation cavities arising from cooperative orientation of free carboxylate groups. An especially interesting feature is the structural memory effect during crystallization exhibited by the metalloligand, even after dissolution and binding to secondary cations (Cu(2+), Cd(2+)…). Moreover, the porous solid can undergo ion-exchange with various anions, leading to tunable thermochromic temperature and color range. PMID:27463609

  20. The thiocyanate anion as a polydentate halogen bond acceptor

    OpenAIRE

    Cauliez, Pascal; Polo, Victor; Roisnel, Thierry; Llhusar, Rosa; Fourmigué, Marc

    2010-01-01

    International audience Co-crystallisation of the Et4N+ or n-Bu4N+ salts of the thiocyanate anion with o-, m- and p-diodoperfluorobenzene or the sym-trifluorotriiodobenzene allowed for the isolation of six different salts which were structurally characterized by single crystal X-ray diffraction. Halogen bonding interactions are observed between the neutral iodinated molecules acting as halogen bond donors and the S or N ends of the thiocyanate anion, with a variety of bonding modes (termina...

  1. Isotope Fractionation of chlorine in Aqueous System: One Study on Anion-Exchange Chromatography.

    Science.gov (United States)

    Musashi, M.; Oi, T.; Eggenkamp, H.; Van Cappellen, P.

    2001-05-01

    Stable chlorine isotopes such as 37Cl and 35Cl have been paid attention as useful tool identifying the source, and monitoring the transport process and natural fate of chlorinated organic pollutants in air and groundwater. However, it is not established yet whether any isotope effects accompany biodegradation or reductive dehalogenation of the pollutants (Clark and Fritz, 1997). Here we first present an experimental determination of isotope fractionation factor of chlorine in aqueous system by using anion-exchange chromatographic technique. Into the Cl-free anion exchange resin (Muromac, OH- form) packed in a 30 cm long pyrex glass column and controlled temperature at 25 oC, hydrochloric solution was fed with controlling the flow rate constant. Effluent from the column was recovered by an automatic fraction collector and prepared for Cl isotope analysis. The Cl isotope ratio (δ 37Cl vs. SMOC) was measured by IR-MS at the Utrecht University with precision of 0.06 per-mil. Magnitude of the factor obtained was 1.00035 at 25 oC. The result indicates that the lighter isotope (35Cl) was preferably fractionated into the resin phase, while the heavier one (37Cl) was enriched into the aqueous phase. This trend suggests that molecular structure of hydrolysis with Cl in aqueous phase may be more stable than that of Cl ionically bonding with the resin. This result may offer physico-chemical insights into behavior and fate of the pollutants.

  2. Electron Photodetachment from Aqueous Anions. I. Quantum Yields for Generation of Hydrated Electron by 193 and 248 nm Laser Photoexcitation of Miscellaneous Inorganic Anions

    CERN Document Server

    Sauer, M C; Shkrob, I A; Sauer, Myran C.; Shkrob, Ilya A.

    2004-01-01

    Time resolved transient absorption spectroscopy has been used to determine quantum yields for electron photodetachment in 193 nm and (where possible) 248 nm laser excitation of miscellaneous aqueous anions, including hexacyanoferrate(II), sulfate, sulfite, halide anions (Cl-, Br-, and I-), pseudohalide anions (OH-, HS-, CNS-), and several common inorganic anions for which no quantum yields have been reported heretofore: SO3=, NO2-, NO3-, ClO3- and ClO4-. Molar extinction coefficients for these anions and photoproducts of electron detachment from these anions at the excitation wavelengths were also determined. These results are discussed in the context of recent ultrafast kinetic studies and compared with the previous data obtained by product analyses. We suggest using electron photodetachment from the aqueous halide and pseudohalide anions as actinometric standard for time-resolved studies of aqueous photosystems in the UV.

  3. Anion-Anion Bonding and Topology in Ternary Iridium Seleno-Stannides

    Energy Technology Data Exchange (ETDEWEB)

    Trump, Benjamin A.; Tutmaher, Jake A.; McQueen, Tyrel M. [JHU

    2016-09-06

    The synthesis and physical properties of two new and one known Ir–Sn–Se compound are reported. Their crystal structures are elucidated with transmission electron microscopy and powder X-ray diffraction. IrSn0.45Se1.55 is a pyrite phase which consists of tilted corner-sharing IrX6 octahedra with randomly distributed (Sn–Se)4– and (Se–Se)2– dimers. Ir2Sn3Se3 is a known trigonally distorted skutterudite that consists of cooperatively tilted corner-sharing IrSn3Se3 octahedra with ordered (Sn–Se)24– tetramers. Ir2SnSe5 is a layered, distorted β-MnO2 (pyrolusite) structure consisting of a double IrSe6 octrahedral row, corner sharing in the a direction and edge sharing in the b direction. This distorted pyrolusite contains (Se–Se)2– dimers and Se2– anions, and each double row is “capped” with a (Sn–Se)n polymeric chain. Resistivity, specific heat, and magnetization measurements show that all three have insulating and diamagnetic behavior, indicative of low-spin 5d6 Ir3+. Electronic structure calculations on Ir2Sn3Se3 show a single, spherical, nonspin–orbit split valence band and suggest that Ir2Sn3Se3 is topologically nontrivial under tensile strain due to inversion of Ir-d and Se-p states.

  4. A new anionic exchange stir bar sorptive extraction coating based on monolithic material for the extraction of inorganic anion.

    Science.gov (United States)

    Huang, Xiaojia; Lin, Jianbing; Yuan, Dongxing

    2010-07-23

    A novel anionic exchange stir bar sorptive extraction (SBSE) coating based on poly(2-(methacryloyloxy)ethyltrimethylammonium chloride-co-divinylbenzene) monolithic material for the extraction of inorganic anion was prepared. The effect of preparation conditions such as ratio of functional monomer to cross-linker, content of porogenic solvent on the extraction efficiencies were investigated in detailed. The monolithic material was characterized by elemental analysis, scanning electron microscopy and infrared spectroscopy. In order to investigate the extraction capacity of the new coating for inorganic anion, the new SBSE was combined with ionic chromatography with conductivity detection, Br-, NO3-, PO4(3-) and SO4(2-) were selected as detected solutes. Several extractive parameters, including pH value and ionic strength in sample matrix, desorption solvent, extraction and desorption time were optimized. The results showed that strongly ionic strength did not favor the extraction of anlaytes. Under the optimum experimental conditions, low detection limits (S/N=3) and quantification limits (S/N=10) of the proposed method for the target anions were achieved within the range of 0.92-2.62 and 3.03-9.25 microg/L, respectively. The method also showed good linearity, simplicity, practicality and low cost for the extraction inorganic anions. Finally, the proposed method was successfully used to detect the two different trademarks of commercial purified water with satisfactory recovery in the range of 70.0-92.6%. To the best of our knowledge, this is the first to use SBSE to enrich inorganic anions. PMID:20576270

  5. Quasielastic neutron scattering study of tetrahydroborate anion dynamical perturbations in sodium borohydride due to partial halide anion substitution

    International Nuclear Information System (INIS)

    Highlights: • NaBH4–NaX (X = Cl, I) solutions were made by ball-milling/annealing pure compounds. • BH4− reorientational motions were studied by quasielastic neutron scattering. • Mobility increased from X = Cl to NaBH4 to X = I, consistent with expanding lattices. • Near 400 K, BH4− favored cubic tumbling for X = Cl and tetrahedral tumbling for X = I. • Activation energies were in the range of 11–12 kJ mol−1 for both compounds. - Abstract: Equimolar NaBH4–NaX (X = Cl and I) solid solutions were synthesized to study, via quasielastic neutron scattering, the effect of partial halide anion substitution on the reorientational dynamics of tetrahydroborate (BH4−) anions in NaBH4. The BH4− reorientational mobility increased in the order of NaBH4–NaCl, NaBH4, and NaBH4–NaI, which corresponded with expanding face-centered-cubic lattices accommodating the respective increasing sizes of the Cl−, BH4−, and I− anions. The BH4− anions in NaBH4–NaCl were found (at least above 400 K) to undergo ‘cubic’ tumbling motions with the four H atoms per anion visiting all eight corners of a cube, similar to what was previously observed for NaBH4. In contrast, the BH4− anions in NaBH4–NaI were found to undergo something more akin to ‘tetrahedral’ tumbling motions, where the H atoms visit all four corners of a tetrahedron. Despite a noticeable softening of the BH4− torsional energies with increasing lattice constant amongst NaBH4 and the two solid solutions, all three compounds exhibited similar activation energies for reorientation of about 11–12 kJ mol−1

  6. Physiological and pharmacological functions of OATP1A/1B transporters

    OpenAIRE

    Steeg, E.

    2010-01-01

    Organic Anion Transporting Polypeptide (OATP; mouse Oatp) transporters of the 1A/1B subfamilies are uptake transporters that mediate the cellular uptake of a wide range of endogenous and xenobiotic compounds. Since OATP1A/1B transporters are expressed in pharmacological important organs, like liver, kidney and small intestine, it has been hypothesized that OATP1A/1B transporters play an important role in drug disposition and elimination. By generating and utilizing novel Oatp1a/1b cluster kno...

  7. Oxidation of silicon surface with atomic oxygen radical anions

    Institute of Scientific and Technical Information of China (English)

    Wang Lian; Song Chong-Fu; Sun Jian-Qiu; Hou Ying; Li Xiao-Guang; Li Quan-Xin

    2008-01-01

    The surface oxidation of silicon (Si) wafers by atomic oxygen radical anions (O- anions) and the preparation of metal-oxide-semiconductor (MOS) capacitors on the O--oxidized Si substrates have been examined for the first time. The O- anions are generated from a recently developed O- storage-emission material of [Ca24Al28O64]4+.4O- (C12A7-O- for short). After it has been irradiated by an O- anion beam (0.5 μA/cm2) at 300℃ for 1-10 hours, the Si wafer achieves an oxide layer with a thickness ranging from 8 to 32 nm. X-ray photoelectron spectroscopy (XPS) results reveal that the oxide layer is of a mixture of SiO2, Si2O3, and Si2O distributed in different oxidation depths. The features of the MOS capacitor of are investigated by measuring capacitance-voltage (C - V) and current-voltage (Ⅰ - Ⅴ) curves. The oxide charge density is about 6.0×1011 cm-2 derived from the C - V curves. The leakage current density is in the order of 10-6 A/cm2 below 4 MV/cm, obtained from the Ⅰ - Ⅴ curves. The Oanions formed by present method would have potential applications to the oxidation and the surface-modification of materials together with the preparation of semiconductor devices.

  8. Anionic surfactant electrical and surface properties of polypyrrole containing

    Czech Academy of Sciences Publication Activity Database

    Omastová, M.; Chehimi, M. M.; Trchová, Miroslava; Stejskal, Jaroslav

    Dublin: Trinity College Dublin, 2006. 110-TH. [International Conference on Science and Technology of Synthetic Metals. 02.07.2006-07.07.2006, Dublin] Grant ostatní: Slovak Ministry of Education (SK) VEGA-2/4024/04 Institutional research plan: CEZ:AV0Z40500505 Keywords : polypyrrole * anionic polymerization Subject RIV: CD - Macromolecular Chemistry

  9. The Determination of Anionic Surfactants in Natural and Waste Waters.

    Science.gov (United States)

    Crisp, P. T.; And Others

    1983-01-01

    Background information, procedures, and results of an experiment suitable for measuring subpart per million concentrations of anionic surfactants in natural waters and waste effluents are provided. The experiment required only a spectrophotometer or filter photometer and has been successfully performed by students in an undergraduate environmental…

  10. Advancing Analytical Methods for Characterization of Anionic Carbohydrate Biopolymers

    OpenAIRE

    Langeslay, Derek Joseph

    2013-01-01

    The focus of this dissertation is on the development of improved analytical methods for the characterization of anionic carbohydrate biopolymers. Our goal is to extract important information from complex mixtures of heterogeneous polysaccharides by characterizing their substituent oligosaccharides in terms of monosaccharide composition and primary and secondary structure. This work focuses on the application of two major analytical platforms: spectroscopy and chromatography. The development ...

  11. Materials chemistry approach to anion-sensor design

    Czech Academy of Sciences Publication Activity Database

    Anzenbacher Jr., P.; Jursiková, K.; Aldakov, D.; Marquez, M.; Pohl, Radek

    2004-01-01

    Roč. 60, č. 49 (2004), s. 11163-11168. ISSN 0040-4020 Institutional research plan: CEZ:AV0Z4055905 Keywords : conductive polymer * anion sensing * polythiophene Subject RIV: CC - Organic Chemistry Impact factor: 2.643, year: 2004

  12. Anion-free bambus[6]uril and its supramolecular properties

    Czech Academy of Sciences Publication Activity Database

    Švec, J.; Dušek, Michal; Fejfarová, Karla; Štacko, P.; Klán, P.; Kaifer, A.E.; Li, W.; Hudečková, E.; Šindelář, V.

    2011-01-01

    Roč. 17, č. 20 (2011), s. 5605-5612. ISSN 0947-6539 Grant ostatní: AVČR(CZ) Praemium Academiae Institutional research plan: CEZ:AV0Z10100521 Keywords : anion receptors * halides * host-guest systems * macrocycles * supramolecular chemistry Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 5.925, year: 2011

  13. Molecular Anions in Protostars, Prestellar Cores and Dark Clouds

    Science.gov (United States)

    Cordiner, Martin; Charnley, Steven; Buckle, Jane; Wash, Catherine; Millar, Tom

    2011-01-01

    From our recent survey work using the Green Bank Telescope, microwave emission lines from the hydrocarbon anion C6H(-) and its parent neutral C6H have been detected in six new sources. Using HC3N = 10(exp -9) emission maps, we targeted the most carbon-chain-rich sources for our anion survey, which included the low-mass Class 0 protostar L1251A-IRS3, the prestellar cores L1389-SMM1 and L1512, and the interstellar clouds Ll172A, TMC-1C and L1495B. Derived [C6H(-)]/[C6H] anion-to-neutral ratios are approximately 1-10. The greatest C6H(-) column densities are found in the quiescent clouds TMC-1C and L1495B, but the anion-to-neutral ratios are greatest in the prestellar cores and protostars. These results are interpreted in terms of the physical and chemical properties of the sources, and the implications for molecular cloud chemistry are discussed.

  14. Capacity gradient anion chromatography with a borate complex as eluent.

    Science.gov (United States)

    Yamamoto, A; Inoue, Y; Kodama, S; Matsunaga, A

    1999-07-30

    Complex formation between borate compounds and vicinal diols is well recognized. Generally, in a chemically bonded anion-exchange resin, many hydroxyl groups are introduced on the surface of the resin in order to make the resin hydrophilic. The borate as an eluting reagent also reacts to these hydroxyl groups, and this complex formation decreases the apparent ion-exchange capacity of the column by being dissociated to the anion depending on the eluent pH. In the present work a method is described for the simultaneous determination of anions based on the capacity gradient for suppressed ion chromatography. A Tosoh IC-Anion-PW column and dihydroxyphenylborane-mannitol eluent system were used. To maintain baseline stability, it was helpful to keep the borate concentration constant during a gradient of 16 to 0 mM mannitol as a modifier to prevent the complex formation with the hydroxyl on the resin. The chemical composition of the eluents and gradient profiles are discussed and the application to the analysis of the condensed phosphates with widely varying retention times as food additives in a cheese sample is presented. PMID:10457467

  15. Synthesis and Anion Recognition of a Novel Heterocyclic Organotin Complex

    Institute of Scientific and Technical Information of China (English)

    Li Xin ZHANG; Gui Zhi LI; Zhi Qiang LI

    2004-01-01

    A novel heterocyclic hexacoordinate organotin(IV) complex, bis(O-vanillin)-semi ethylenediamino dibenzyltin (VEDBT) was synthesized by the reaction of dibenzyltin dichloride with bis(O-vanillin)-semiethyenediamine, its structure has been characterized by spectral methods.The electrodes using VEDBT as a neutral carrier show high selectivity for salicylate anions.

  16. Functional Block Copolymers via Anionic Polymerization for Electroactive Membranes

    OpenAIRE

    Schultz, Alison

    2013-01-01

           Ion-containing block copolymers blend ionic liquid properties with well-defined polymer architectures. This provides conductive materials with robust mechanical stability, efficient processability, and tunable macromolecular design. Conventional free radical polymerization and anion exchange achieved copolymers containing n-butyl acrylate and phosphonium ionic liquids. These compositions incorporated vinylbenzyl triphenyl phosphonium and vinylbenzyl tricyclohexyl phosphonium cations be...

  17. Rejuvenation processes applied to 'poisoned' anion exchangers in uranium processing

    International Nuclear Information System (INIS)

    The removal of 'poisons' from anion exchangers in uranium processing of Canadian radioactive ores is commonly called rejuvenation or regeneration. The cost of the ion exchange recovery of uranium is adversely affected by a decrease in the capacity and efficiency of the anion exchangers, due to their being 'poisoned' by silica, elemental sulphur, molybdenum and tetrathionates. These 'poisons' have a high affinity for the anion exchangers, are adsorbed in preference to the uranyl complex, and do not desorb with the reagents used normally in the uranyl desorption phase. The frequency of rejuvenation and the reagents required for rejuvenation are determined by the severity of the 'poisoning' accumulated by the exchanger in contact with the uranium leach liquor. Caustic soda (NaOH) at approximately equal to 18 cents/lb is commonly used to remove uranium anion exchangers of tetrathionate ((S406)/-/-) 'poisons'. A potential saving in operating cost would be of consequence if other reagents, e.g. sodium carbonate (Na2CO3) at approximately equal to 3.6 cents/lb or calcium hydroxide (Ca(OH)2) at approximately equal to 1.9 cents/lb, were effective in removing (S406)/-/-) from a 'poisoned' exchanger. A rejuvenation process for a test program was adopted after a perusal of the literature

  18. Anionic micelles and vesicles induce tau fibrillization in vitro.

    Science.gov (United States)

    Chirita, Carmen N; Necula, Mihaela; Kuret, Jeff

    2003-07-11

    Alzheimer's disease is defined in part by the intraneuronal accumulation of filaments comprised of the microtubule-associated protein tau. In vitro, fibrillization of recombinant tau can be induced by treatment with various agents, including phosphotransferases, polyanionic compounds, and fatty acids. Here we characterize the structural features required for the fatty acid class of tau fibrillization inducer using recombinant full-length tau protein, arachidonic acid, and a series of straight chain anionic, cationic, and nonionic detergents. Induction of measurable tau fibrillization required an alkyl chain length of at least 12 carbons and a negative charge consisting of carboxylate, sulfonate, or sulfate moieties. All detergents and fatty acids were micellar at active concentrations, due to a profound, taudependent depression of their critical micelle concentrations. Anionic surfaces larger than detergent micelles, such as those supplied by phosphatidylserine vesicles, also induced tau fibrillization with resultant filaments originating from their surface. These data suggest that anionic surfaces presented as micelles or vesicles can serve to nucleate tau fibrillization, that this mechanism underlies the activity of fatty acid inducers, and that anionic membranes may serve this function in vivo. PMID:12730214

  19. Anion complexation by calix[4]arene–TTF conjugates

    Czech Academy of Sciences Publication Activity Database

    Flídrová, K.; Tkadlecová, M.; Lang, Kamil; Lhoták, P.

    2012-01-01

    Roč. 92, č. 1 (2012), s. 668-673. ISSN 0143-7208 R&D Projects: GA ČR GA203/09/0691 Institutional research plan: CEZ:AV0Z40320502 Keywords : calix[4]arene * tetrathiafulvalene * anion recognition * receptor * NMR titration * UV/vis spectroscopy Subject RIV: CA - Inorganic Chemistry Impact factor: 3.532, year: 2012

  20. The D‐amino acid transport by the invertebrate SLC6 transporters KAAT1 and CAATCH1 from Manduca sexta

    OpenAIRE

    Vollero, Alessandra; Imperiali, Francesca G.; Cinquetti, Raffaella; Margheritis, Eleonora; Peres, Antonio; Bossi, Elena

    2016-01-01

    Abstract The ability of the SLC6 family members, the insect neutral amino acid cotransporter KAAT1(K+‐coupled amino acid transporter 1) and its homologous CAATCH1(cation anion activated amino acid transporter/channel), to transport D‐amino acids has been investigated through heterologous expression in Xenopus laevis oocytes and electrophysiological techniques. In the presence of D‐isomers of leucine, serine, and proline, the ms KAAT1 generates inward, transport‐associated, currents with varia...

  1. Leishmania amazonensis: Anionic currents expressed in oocytes upon microinjection of mRNA from the parasite.

    Science.gov (United States)

    Lagos M, Luisa F; Moran, Oscar; Camacho, Marcela

    2007-06-01

    Transport mechanisms involved in pH homeostasis are relevant for the survival of Leishmania parasites. The presence of chloride conductive pathways in Leishmania has been anticipated since anion channel inhibitors limit the proton extrusion mediated by the H+ATPase, which is the major regulator of intracellular pH in amastigotes. In this study, we used Xenopus laevis oocytes as a heterologous expression system in which to study the expression of ion channels upon microinjection of polyA mRNA from Leishmania amazonensis. After injection of polyA mRNA into the oocytes, we measured three different types of currents. We discuss the possible origin of each, and propose that Type 3 currents could be the result of the heterologous expression of proteins from Leishmania since they show different pharmacological and biophysical properties as compared to endogenous oocyte currents. PMID:17328895

  2. Endothelium modulates anion channel-dependent aortic contractions to iodide.

    Science.gov (United States)

    Lamb, F S; Barna, T J

    2000-05-01

    Anion currents contribute to vascular smooth muscle (VSM) membrane potential. The substitution of extracellular chloride (Cl) with iodide (I) or bromide (Br) initially inhibited and then potentiated isometric contractile responses of rat aortic rings to norepinephrine. Anion substitution alone produced a small relaxation, which occurred despite a lack of active tone and minimal subsequent contraction of endothelium-intact rings (4.2 +/- 1.2% of the response to 90 mM KCl). Endothelium-denuded rings underwent a similar initial relaxation but then contracted vigorously (I > Br). Responses to 130 mM I (93.7 +/- 1.9% of 90 mM KCl) were inhibited by nifedipine (10(-6) M), niflumic acid (10(-5) M), tamoxifen (10(-5) M), DIDS (10(-4) M), and HCO(-)(3)-free buffer (HEPES 10 mM) but not by bumetanide (10(-5) M). Intact rings treated with N(omega)-nitro-L-arginine (10(-4) M) responded weakly to I (15.5 +/- 2.1% of 90 mM KCl), whereas hemoglobin (10(-5) M), indomethacin (10(-6) M), 17-octadecynoic acid (10(-5) M), and 1H-[1,2, 4]oxadiazole[4,3-a]quinoxalin-1-one (10(-6) M) all failed to augment the response of intact rings to I. We hypothesize that VSM takes up I primarily via an anion exchanger. Subsequent I efflux through anion channels having a selectivity of I > Br > Cl produces depolarization. In endothelium-denuded or agonist-stimulated vessels, this current is sufficient to activate voltage-dependent calcium channels and cause contraction. Neither nitric oxide nor prostaglandins are the primary endothelial modulator of these anion channels. If they are regulated by an endothelium-dependent hyperpolarizing factor it is not a cytochrome P-450 metabolite. PMID:10775130

  3. Ciprofloxacin Is Actively Transported across Bronchial Lung Epithelial Cells Using a Calu-3 Air Interface Cell Model

    OpenAIRE

    Ong, Hui Xin; Traini, Daniela; Bebawy, Mary; Young, Paul M.

    2013-01-01

    Ciprofloxacin is a well-established broad-spectrum fluoroquinolone antibiotic that penetrates well into the lung tissues; still, the mechanisms of its transepithelial transport are unknown. The contributions of specific transporters, including multidrug efflux transporters, organic cation transporters, and organic anion-transporting polypeptide transporters, to the uptake of ciprofloxacin were investigated in vitro using an air interface bronchial epithelial model. Our results demonstrate tha...

  4. Reducing nitrogen crossover in microbial reverse-electrodialysis cells by using adjacent anion exchange membranes and anion exchange resin

    KAUST Repository

    Wallack, Maxwell J.

    2015-01-01

    Microbial reverse electrodialysis cells (MRECs) combine power generation from salinity gradient energy using reverse electrodialysis (RED), with power generation from organic matter using a microbial fuel cell. Waste heat can be used to distill ammonium bicarbonate into high (HC) and low salt concentration (LC) solutions for use in the RED stack, but nitrogen crossover into the anode chamber must be minimized to avoid ammonia loses, and foster a healthy microbial community. To reduce nitrogen crossover, an additional low concentration (LC) chamber was inserted before the anode using an additional anion exchange membrane (AEM) next to another AEM, and filled with different amounts of anion or cation ion exchange resins. Addition of the extra AEM increased the ohmic resistance of the test RED stack from 103 Ω cm2 (1 AEM) to 295 Ω cm2 (2 AEMs). However, the use of the anion exchange resin decreased the solution resistance of the LC chamber by 74% (637 Ω cm2, no resin; 166 Ω cm2 with resin). Nitrogen crossover into the anode chamber was reduced by up to 97% using 50% of the chamber filled with an anion exchange resin compared to the control (no additional chamber). The added resistance contributed by the use of the additional LC chamber could be compensated for by using additional LC and HC membrane pairs in the RED stack.

  5. Dramatic enhancement of fullerene anion formation in polymer solar cells by thermal annealing: Direct observation by electron spin resonance

    International Nuclear Information System (INIS)

    Using electron spin resonance (ESR), we clarified the origin of the efficiency degradation of polymer solar cells containing a lithium-fluoride (LiF) buffer layer created by a thermal annealing process after the deposition of an Al electrode (post-annealing). The device structure was indium-tin-oxide/ poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)/poly (3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PCBM)/LiF/Al. Three samples consisting of quartz/P3HT:PCBM/LiF/Al, quartz/P3HT:PCBM/Al, and quartz/PCBM/LiF/Al were investigated and compared. A clear ESR signal from radical anions on the PCBM was observed after LiF/Al was deposited onto a P3HT:PCBM layer because of charge transfer at the interface between the PCBM and the LiF/Al, which indicated the formation of PCBM−Li+ complexes. The number of radical anions on the PCBM was enhanced remarkably by the post-annealing process; this enhancement was caused by the surface segregation of PCBM and by the dissociation of LiF at the Al interface by the post-annealing process. The formation of a greater number of anions enhanced the electron scattering, decreased the electron-transport properties of the PCBM molecules, and caused an energy-level shift at the interface. These effects led to degradation in the device performance.

  6. Stimulating effects of a diet negative in dietary cation-anion difference on calcium absorption from the rumen in sheep.

    Science.gov (United States)

    Wilkens, M R; Praechter, C; Breves, G; Schröder, B

    2016-02-01

    The concept of feeding anionic salts in late gestation is widely used to prevent milk fever in dairy cows. While the effects of these diets on renal Ca excretion and tissue responsiveness towards parathyroid hormone have clearly been demonstrated, data on a potential impact on gastrointestinal Ca absorption are conflicting. Therefore, the aim of this study was to investigate the influence of feeding a diet negative in dietary cation-anion difference (DCAD) on ruminal mineral concentrations, fermentation products, electrophysiological properties of rumen epithelia and Ca flux rates. For this purpose, sheep were kept for 3 weeks on diets that were either positive or negative in DCAD. The induction of a compensated hyperchloremic metabolic acidosis could be demonstrated by increased plasma Cl and enhanced concentrations of ionised Ca, while plasma concentrations of HCO3- and base excess were decreased with the low DCAD diet. Neither transmural potential differences nor fermentation products were affected, but ruminal concentrations of Cl and Mg as well as the relation of ionised to total Ca were increased. Ussing chamber experiments revealed alterations of electrophysiological parameters and an increase in the electroneutral component of Ca flux rates from the mucosal to the serosal side of rumen epithelium. As plasma calcitriol concentrations were not affected, it can be concluded that the administration of anionic salts results in a vitamin D-independent stimulation of ruminal Ca transport. PMID:25643625

  7. Azide anions inhibit GH-18 endochitinase and GH-20 Exo β-N-acetylglucosaminidase from the marine bacterium Vibrio harveyi.

    Science.gov (United States)

    Sirimontree, Paknisa; Fukamizo, Tamo; Suginta, Wipa

    2016-02-01

    Vibrio harveyi is a bioluminescent marine bacterium that utilizes chitin as its sole source of energy. In the course of chitin degradation, the bacterium primarily secretes an endochitinase A (VhChiA) to hydrolyze chitin, generating chitooligosaccharide fragments that are readily transported into the cell and broken down to GlcNAc monomers by an exo β-N-acetylglucosaminidase (VhGlcNAcase). Here we report that sodium salts, especially sodium azide, inhibit two classes of these chitin-degrading enzymes (VhChiA and VhGlcNAcase) with distinct modes of action. Kinetic analysis of the enzymatic hydrolysis of pNP-glycoside substrates reveals that sodium azide inhibition of VhChiA has a mixed-type mode, but that it inhibits VhGlcNAcase competitively. We propose that azide anions inhibit chitinase activity by acting as strong nucleophiles that attack Cγ of the catalytic Glu or Cβ of the neighbouring Asp residues. Azide anions may bind not only to the catalytic centre, but also to the other subsites in the substrate-binding cleft of VhChiA. In contrast, azide anions may merely occupy the small-binding pocket of VhGlcNAcase, thereby blocking the accessibility of its active site by short-chain substrates. PMID:26330565

  8. Influence of anionic monomer content on the biodegradation and toxicity of polyvinyl-urethane carbonate-ceramic interpenetrating phase composites.

    Science.gov (United States)

    Yang, Liu; Hong, Jason; Wang, Jian; Pilliar, Robert M; Santerre, J Paul

    2005-10-01

    The objective of this study was to characterize a series of anionic biodegradable polymer resins for their compatibility in a biological environment, comparing them with respect to the influence of ionic function on enzyme catalyzed biodegradation when the polymers were incorporated into a porous calcium polyphosphate (CPP) 3-D structure to form an interpenetrating phase composite (IPC). The swelling behavior of the polymers was investigated by immersing the cured polymer resins in growth media at 37 degrees C. In vitro cytotoxicity of the polymer resins was assessed using a HeLa cell line. Cell viability increased when the amount of low molecular weight monomer was minimized. Despite observing that the addition of carboxylic acid groups into the polymer resin chains contributed to an improvement of the chemical bonding between the polymer and the CPP, the addition of high ionic content into the resin led to the greatest loss of bending strength for the samples incubated in phosphate buffer and cholesterol esterase enzyme solutions, when compared to their as made state. The increased degradation for the higher ionic component materials and their loss of physical strength was attributed to enhanced hydrolysis within the materials and by water transport deep within the composites, via the anionic components of the resin. The findings indicated that the introduction of anionic content must be optimized to promote increased mechanical performance for the CPP, balancing the features of polymer CPP bonding versus polymer swelling and cytotoxicity. PMID:15958241

  9. Controlled Release Kinetics in Hydroxy Double Salts: Effect of Host Anion Structure

    OpenAIRE

    Stephen Majoni; Jeanne M. Hossenlopp

    2014-01-01

    Nanodimensional layered metal hydroxides such as layered double hydroxides (LDHs) and hydroxy double salts (HDSs) can undergo anion exchange reactions releasing intercalated anions. Because of this, these metal hydroxides have found applications in controlled release delivery of bioactive species such as drugs and pesticides. In this work, isomers of hydroxycinnamate were used as model compounds to systematically explore the effects of anion structure on the rate and extent of anion release i...

  10. Supramolecular chemistry of selective anion recognition for anions of environmental relevance. Progress report, October 1996--July 1997

    Energy Technology Data Exchange (ETDEWEB)

    Bowman-James, K.; Wilson, G.S.; Kuczera, K. [Univ. of Kansas, Lawrence, KS (US); Moyer, B. [Oak Ridge National Lab., TN (US)

    1997-01-01

    'This project has as its focus the design and synthesis of polyammonium macrocyclic receptors for oxoanions of environmental importance. The basic research aspects of this project involve synthesis (and the search for improved synthetic methods), solid state structure determination and thermodynamics studies (to ascertain structural criteria for and strength of anion binding), and molecular dynamics simulations (to assess solution characteristics of the interactions between anions and their receptors). Applications-oriented goals include the fabrication of more efficient anion-selective electrodes and the use of these compounds in liquid- liquid separations. The latter goal is the subcontract with Bruce Moyer at Oak Ridge National Laboratory. This first year the authors have focused on nitrates and phosphates. Considerable progress has been made in the basic areas of synthesis, solid state Structure, and molecular dynamics. Anion selective electrodes have also be made which show promising selectivities for oxoanions of interest. Below are described the major findings and significance in the categories of synthesis, structure and molecular dynamics, and electrode studies. Synthesis. The synthesis of polyaza macrocycles which are the focus of these studies is often tedious and time-consuming. A major breakthrough which the authors have made this year is to identify other polyaza macrocycles, which also bind the desired anions, but which are simpler to synthesize via a two step Schiff base/reduction process with high yields. This is truly significant since now the authors can obtain large quantities of the macrocycles and do multiple studies at once (crystallizations, thermodynamics, electrode, and eventually separations). Most of their studies to date have focused on monocyclic systems, but they are now beginning to examine bicyclic macrocycles, which can be synthesized by the same method starting with the tetraamine known as tren.'

  11. Improving the Enzyme Catalytic Efficiency Using Ionic Liquids with Kosmotropic Anions

    Institute of Scientific and Technical Information of China (English)

    ZHAO, Hua; CAMPBELL, Sophia; SOLOMON, Jonathan; SONG, Zhi-Yan; OLUBAJO, Olarongbe

    2006-01-01

    The kosmotropicity of cations and anions in ionic liquids has a strong influence on the enzyme catalytic efficiency in aqueous environments. The kosmotropic anion CF3COO- seemed to activate the protease, and the chaotropic anions tended to destabilize the enzyme.

  12. Synthesis of unsymmetrical N-carboranyl NHCs: directing effect of the carborane anion.

    Science.gov (United States)

    Asay, Matthew J; Fisher, Steven P; Lee, Sarah E; Tham, Fook S; Borchardt, Dan; Lavallo, Vincent

    2015-03-28

    The syntheses of unsymmetrical N-heterocyclic carbenes (NHCs) that contain a single N-bound icosahedral carborane anion substituent are reported. Both anionic C-2 and doubly deprotonated dianionic C-2/C-5 NHC lithium complexes are isolated. The latter species is formed selectively, which reveals a surprising directing effect conveyed by icosahedral carborane anion substituents. PMID:25387660

  13. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance. Final Report

    International Nuclear Information System (INIS)

    increased understanding of the chemical rules that govern the selective sequestration of anions.

  14. Facile synthesis of hollow silica nanospheres employing anionic PMANa templates

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yan; Takai, Chika; Shirai, Takashi; Fuji, Masayoshi, E-mail: fuji@nitech.ac.jp [Nagoya Institute of Technology, Advanced Ceramic Research Center (Japan)

    2015-05-15

    This article presents a facile and green route to the synthesis of hollow silica particles by means of anionic particles of poly(sodium methacrylate) (PMANa) as templates. This method was composed of the following three steps: formation of PMANa particles in ethanol by nanoprecipitation, the deposition of silica shell on the polymer cores through sol–gel process of tetraethylorthosilicate under catalysis of ammonia, and removal of the polymer templates by washing with water. The templates’ size can be controlled in the range of about 70–140 nm by altering the ratio of ethanol to water, the polymer solution concentration, the ethanol amount in polymer solution, and the silica shell thickness can be adjusted between 15 and 30 nm by varying the ratio of silica precursor to the polymer cores. A tentative interpretation about the silica-coating process on the anionic PMANa particles was also proposed according to the experimental results.

  15. Electronic spectra of anions intercalated in layered double hydroxides

    Indian Academy of Sciences (India)

    S Radha; P Vishnu Kamath

    2013-10-01

    Transition metal complexes intercalated in layered double hydroxides have a different electronic structure as compared to their free state owing to their confinement within the interlayer gallery. UV–Vis absorptions of the intercalated complex anions show a significant shift as compared to their free state. The ligand to metal charge transfer transitions of the ferricyanide anion show a red shift on intercalation. The ferrocyanide ion shows a significant blue shift of – bands due to the increased separation between 2g and g levels on intercalation. MnO$^{-}_{4}$ ion shows a blue shift in its ligand to metal charge transfer transition since the non-bonding 1 level of oxygen from which the transition arises is stabilized.

  16. Thermal Properties of Anionic Polyurethane Composition for Leather Finishing

    Directory of Open Access Journals (Sweden)

    Olga KOVTUNENKO

    2016-09-01

    Full Text Available Thermal properties of anionic polyurethane composition mixed with collagen product and hydrophilic sodium form of montmorillonite for use in the finishing of leather were studied by thermogravimetric method. The thermal indices of processes of thermal and thermo-oxidative destruction depending on the polyurethane composition were determined. The influence of anionic polyurethane composition on thermal behavior of chromium tanned gelatin films that imitate the leather were studied. APU composition with natural compounds increases their thermal stability both in air and in nitrogen atmosphere due to the formation of additional bonds between active groups of APU, protein and chrome tanning agent as the result of chemical reactions between organic and inorganic parts with the new structure formation.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.10043

  17. The immobilization of anion exchange resins in polymer modified cements

    International Nuclear Information System (INIS)

    Organic anion exchange resins, loaded with 99-Tc as the pertechnate ion, were incorporated into polymer modified cements (Flexocrete Ltd, Preston). BFS/OPC (9:1 mix) also was modified by three polymers from the same source (styrene acrylic (2) styrene butadiene) and loaded with anion exchanger containing the pertechnate. Composites were tested for initial compressive strengths, under water and radiation stability and leach rate. IAEA standard leach testing was with simulated sea and ground waters. Ground water leaching also was carried out on composites subjected to 1.109 rads (γ). Leach testing correlated well with compressive strength. Modified composites performed better than the BFS/OPC mix under all conditions studied and were able to encapsulate higher resin loadings. (author)

  18. Mechanism of boric acid sorption on strongly basic anion exchangers

    International Nuclear Information System (INIS)

    The sorption was studied of boric acid at different temperatures and initial solution concentrations on the strongly basic anion exchange resin DIAION SA10A. The pH value of the ion exchange resin phase was determined using acidobasic indicators. The results of measurement, mathematically and graphically processed show that the increased sorption capacity of strongly basic anion exchange resins resulting from the increased concentration of the boric acid sorption solution is due to the presence of the polyborate forms (B3O3(OH)4- and B3O3(OH)52-) in the ion exchange phase. Increasing the temperature results in boric acid release from the ion exchange resin as a result of the transformation of sorbed polyborate forms to the simpler (B(OH)4-) forms. (Ha)

  19. Separation of B-10 with weakly basic anion exchange resin

    International Nuclear Information System (INIS)

    In the study of B-10 isotope separation with weakly basic anion exchanger, the sorption isotherms of boric acid on WA-21 weak-base anion exchange resin and the sorption band shapes as well as its migration velocities in a four-inch diameter ion exchange column, were studied. The isotherms show S-shapes with gentle slope at both low concentration and high concentration regions. In the band migration study, it has been found that these S-shaped isotherms affected the velocities of the peak maximum as the band migrated along the column. The velocities could be calculated with the simple solute movement equation. These results suggest that sorption of molecular species, rather than ion exchange of the counterions is the main process that occurs inside the pores of a weak-base ion exchange resin which is in contact with a very weak electrolytic solution, such as that of boric acid. (author)

  20. Macrocyclic bis(ureas as ligands for anion complexation

    Directory of Open Access Journals (Sweden)

    Claudia Kretschmer

    2014-08-01

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

  1. Facile synthesis of hollow silica nanospheres employing anionic PMANa templates

    International Nuclear Information System (INIS)

    This article presents a facile and green route to the synthesis of hollow silica particles by means of anionic particles of poly(sodium methacrylate) (PMANa) as templates. This method was composed of the following three steps: formation of PMANa particles in ethanol by nanoprecipitation, the deposition of silica shell on the polymer cores through sol–gel process of tetraethylorthosilicate under catalysis of ammonia, and removal of the polymer templates by washing with water. The templates’ size can be controlled in the range of about 70–140 nm by altering the ratio of ethanol to water, the polymer solution concentration, the ethanol amount in polymer solution, and the silica shell thickness can be adjusted between 15 and 30 nm by varying the ratio of silica precursor to the polymer cores. A tentative interpretation about the silica-coating process on the anionic PMANa particles was also proposed according to the experimental results

  2. Anion analysis using capillary electrophoresis in the Halden reactor

    International Nuclear Information System (INIS)

    A significant investment has been made over the last decade in water chemistry analysis capability at the Halden Reactor, reflecting both the need to maintain system reliability and to provide chemical analyses for the increasing number of corrosion and chemistry-related experiments being performed in the reactor. Control of concentrations of anionic species (chloride, sulphate and nitrate) is of crucial importance in reducing the potential of stainless steel components to undergo stress corrosion cracking. Currently at Halden, samples must be taken from the coolant in the reactor itself, several auxiliary systems and approximately 10 test loop systems. Previously, anion analyses were performed using ion chromatography. In 1996, this technique was superseded by capillary electrophoresis since the latter has several advantages over the former, including speed of analysis. This paper will present operational experience of using capillary electrophoresis from two different suppliers. A discussion of the advantages and disadvantages of the technique over ion chromatography is included. (author)

  3. Microsolvation effects on the electron binding energies of halide anions

    Science.gov (United States)

    Dolgounitcheva, O.; Zakrzewski, V. G.; Streit, L.; Ortiz, J. V.

    2014-02-01

    Ab initio electron propagator calculations in the partial third order (P3) and P3+ approximations were performed to obtain vertical electron detachment energies (VEDEs) of fluoride and chloride clusters with one through three molecules of water. Larger clusters of F- and Cl- with six water molecules were also treated with and without the polarisable continuum model (PCM). For the smaller clusters, good agreement between calculated VEDEs and peak positions in photoelectron spectra is achieved. Large shifts in VEDEs are observed for both hexameric fluoride-water and chloride-water complexes when the PCM is applied. Significant changes in coordination geometries about the chloride anion also occur in this model. In all fluoride complexes, Dyson orbitals for the lowest VEDEs are delocalised over oxygen atoms. On the contrary, for the case of chloride-water clusters, the Dyson orbitals corresponding to the lowest VEDEs are localised on the anion.

  4. Transport policy

    OpenAIRE

    1980-01-01

    Transport is a fundamental component of all modern economies. Transport Policy presents a wide ranging collection of previously published articles which aim to provide the reader with an understanding of the main elements of transport policy.

  5. Quasielastic neutron scattering study of tetrahydroborate anion dynamical perturbations in sodium borohydride due to partial halide anion substitution

    Energy Technology Data Exchange (ETDEWEB)

    Verdal, Nina [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102 (United States); Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742-2115 (United States); Udovic, Terrence J. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102 (United States); Rush, John J. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102 (United States); Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742-2115 (United States); Skripov, Alexander V. [Institute of Metal Physics, Ural Branch of the Russian Academy of Sciences, Ekaterinburg 620990 (Russian Federation)

    2015-10-05

    Highlights: • NaBH{sub 4}–NaX (X = Cl, I) solutions were made by ball-milling/annealing pure compounds. • BH{sub 4}{sup −} reorientational motions were studied by quasielastic neutron scattering. • Mobility increased from X = Cl to NaBH{sub 4} to X = I, consistent with expanding lattices. • Near 400 K, BH{sub 4}{sup −} favored cubic tumbling for X = Cl and tetrahedral tumbling for X = I. • Activation energies were in the range of 11–12 kJ mol{sup −1} for both compounds. - Abstract: Equimolar NaBH{sub 4}–NaX (X = Cl and I) solid solutions were synthesized to study, via quasielastic neutron scattering, the effect of partial halide anion substitution on the reorientational dynamics of tetrahydroborate (BH{sub 4}{sup −}) anions in NaBH{sub 4}. The BH{sub 4}{sup −} reorientational mobility increased in the order of NaBH{sub 4}–NaCl, NaBH{sub 4}, and NaBH{sub 4}–NaI, which corresponded with expanding face-centered-cubic lattices accommodating the respective increasing sizes of the Cl{sup −}, BH{sub 4}{sup −}, and I{sup −} anions. The BH{sub 4}{sup −} anions in NaBH{sub 4}–NaCl were found (at least above 400 K) to undergo ‘cubic’ tumbling motions with the four H atoms per anion visiting all eight corners of a cube, similar to what was previously observed for NaBH{sub 4}. In contrast, the BH{sub 4}{sup −} anions in NaBH{sub 4}–NaI were found to undergo something more akin to ‘tetrahedral’ tumbling motions, where the H atoms visit all four corners of a tetrahedron. Despite a noticeable softening of the BH{sub 4}{sup −} torsional energies with increasing lattice constant amongst NaBH{sub 4} and the two solid solutions, all three compounds exhibited similar activation energies for reorientation of about 11–12 kJ mol{sup −1}.

  6. Impact of microstructure on anion exclusion in compacted clay media

    OpenAIRE

    Tournassat, Christophe; Gaboreau, Stéphane; Robinet, Jean-Charles; Bourg, Ian C.; Steefel, Carl I

    2015-01-01

    International audience The sensitivity of ion concentration distribution models to three key model assumptions, the pore-size distribution of clay media, the distance of closest approach of ions to the clay surface, and the accessibility of sub-nanometer-wide clay mineral interlayer spaces to anions, was explored by solving the Poisson-Boltzmann equation for swelling and non-swelling clay materials. Our calculations show that all three model assumptions significantly impact values predicte...

  7. Local impermeant anions establish the neuronal chloride concentration

    DEFF Research Database (Denmark)

    Glykys, J; Dzhala, V; Egawa, K;

    2014-01-01

    Neuronal intracellular chloride concentration [Cl(-)](i) is an important determinant of γ-aminobutyric acid type A (GABA(A)) receptor (GABA(A)R)-mediated inhibition and cytoplasmic volume regulation. Equilibrative cation-chloride cotransporters (CCCs) move Cl(-) across the membrane, but accumulat...... anions determine the homeostatic set point for [Cl(-)], and hence, neuronal volume and the polarity of local GABA(A)R signaling....

  8. Synthesis of Cationic Extended Frameworks for Anion-Based Applications

    OpenAIRE

    Fei, Honghan

    2012-01-01

    Many of the metal pollutants listed as priorities by the EPA (U.S. Environmental Protection Agency) occur in water as their oxo-hydroxo anionic forms (e.g. perchlorate, chromate, selenite, etc.). Radioactive technetium (Tc-99) in the form of soluble pertechnetate (TcO4−) is highly problematic in low-activity waste (LAW) to separate the nuclear waste into primary solids. Its easy leakage from glass after vitrification does not meet long-term storage performance assessment requirements. ...

  9. Organic resin anion exchangers for the treatment of radioactive wastes

    International Nuclear Information System (INIS)

    Organic anion exchange resins are evaluated for 99-TcO4- (pertechnate) removed from aqueous nuclear waste streams. Chemical, thermal and radiation stabilities were studied. Selected resins were examined in detail for their selectivities in the presence of I-, NO3-, SO4=, CO3=, Cl- and OH-. Ion exchange equilibria and kinetic mechanisms were determined. Preliminary investigations of cement encapsulation in polymer modified form were made and some leach studies carried out. (author)

  10. Quasi-Chemical and Structural Analysis of Polarizable Anion Hydration

    OpenAIRE

    Rogers, David M.; Beck, Thomas L.

    2009-01-01

    Quasi-chemical theory is utilized to analyze the roles of solute polarization and size in determining the structure and thermodynamics of bulk anion hydration for the Hofmeister series Cl$^-$, Br$^-$, and I$^-$. Excellent agreement with experiment is obtained for whole salt hydration free energies using the polarizable AMOEBA force field. The quasi-chemical approach exactly partitions the solvation free energy into inner-shell, outer-shell packing, and outer-shell long-ranged contributions by...

  11. Factors Affecting Anion Movement and Retention in Four Forest Soils

    OpenAIRE

    D. W. Johnson; Cole, D. W.; Van Miegroet, Helga; Horng, F. W.

    1986-01-01

    Three hypotheses concerning the movement and retention of anions in forest soils were tested in a series of laboratory and field studies on two Tennessee Ultisols with mixed deciduous forest cover and two Washington Inceptisols, one with deciduous (red alder Alnus rubra Bong.) and one with coniferous [Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco] forest cover. The first hypothesis, that sulfate and phosphate retention was related to adsorption to free Fe and Al oxides, which were in turn...

  12. Uptake of trace elements in human hair by anion exchange

    International Nuclear Information System (INIS)

    The sorption of some trace elements to human hair is studied by means of radioactive tracers. Experiments with 59Fe, 64Cu, 65Zn, 72Ga and 115Cd in HCl media show a great similarity between human hair and Dowex 1-x10, indicating that the hair acts as a strongly basic anion exchanger. A corresponding similarity with strong cation exchangers is not found. Specific sorption of trace elements seems to be of little use in hair identification studies. (author)

  13. Thermal behaviour of synthetic pyroaurite-like anionic clay

    Czech Academy of Sciences Publication Activity Database

    Kovanda, F.; Balek, Vladimír; Dorničák, V.; Martinec, Petr; Mašláň, M.; Vaculíková, Lenka; Koloušek, D.; Bountsewa, M.

    2003-01-01

    Roč. 71, - (2003), s. 727-737. ISSN 0368-4466 R&D Projects: GA ČR GA202/00/0982; GA ČR GA106/02/0523 Institutional research plan: CEZ:AV0Z4032918; CEZ:AV0Z3086906 Keywords : pyroaurite-like anionic clay * thermal decomposition Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.094, year: 2003

  14. Thermal behaviour of synthetic pyroaurite-like anionic clay

    Czech Academy of Sciences Publication Activity Database

    Kovanda, F.; Balek, Vladimír; Dorničák, V.; Martinec, P.; Mašláň, M.; Bílková, L.; Koloušek, D.; Bountsewa, I. M.

    2003-01-01

    Roč. 72, č. 1 (2003), s. 727-737. ISSN 1388-6150 R&D Projects: GA MŠk LN00A028; GA ČR GA202/00/0982; GA ČR GA106/02/0523 Institutional research plan: CEZ:AV0Z4032918 Keywords : layered double hydroxide * pyroaurite-like anionic clay * thermal decomposition Subject RIV: CA - Inorganic Chemistry Impact factor: 1.094, year: 2003

  15. Inorganic anion exchangers for the treatment of radioactive wastes

    International Nuclear Information System (INIS)

    Inorganic anion exchangers are evaluated for Tc, I and S isotope removal from aqueous nuclear waste streams. Chemical, thermal, and radiation stabilities were examined. Selected exchangers were examined in detail for their selectivities, kinetics and mechanism of the sorption process (especially in NO3-, OH- and BO3- environments). Cement encapsulation and leaching experiments were made on the exchangers showing most promise for 'radwaste' treatment. (author)

  16. A Novel Methodology to Synthesize Highly Conductive Anion Exchange Membranes

    OpenAIRE

    Yubin He; Jiefeng Pan; Liang Wu; Yuan Zhu; Xiaolin Ge; Jin Ran; ZhengJin Yang; Tongwen Xu

    2015-01-01

    Alkaline polyelectrolyte fuel cell now receives growing attention as a promising candidate to serve as the next generation energy-generating device by enabling the use of non-precious metal catalysts (silver, cobalt, nickel et al.). However, the development and application of alkaline polyelectrolyte fuel cell is still blocked by the poor hydroxide conductivity of anion exchange membranes. In order to solve this problem, we demonstrate a methodology for the preparation of highly OH− conductiv...

  17. Block and Graft Copolymers Containing Carboxylate or Phosphonate Anions

    OpenAIRE

    Hu, Nan

    2014-01-01

    This dissertation focuses on synthesis and characterization of graft and block copolymers containing carboxylate or phosphonate anions that are potential candidates for biomedical applications such as drug delivery and dental adhesives. Ammonium bisdiethylphosphonate (meth)acrylate and acrylamide phosphonate monomers were synthesized based on aza-Michael addition reactions. Free radical copolymerizations of these monomers with an acrylate-functional poly(ethylene oxide) (PEO) macromonomer...

  18. Comment on "Local impermeant anions establish the neuronal chloride concentration".

    Science.gov (United States)

    Luhmann, Heiko J; Kirischuk, Sergei; Kilb, Werner

    2014-09-01

    Glykys et al. (Reports, 7 February 2014, p. 670) proposed that cytoplasmic impermeant anions and polyanionic extracellular matrix glycoproteins establish the local neuronal intracellular chloride concentration, [Cl(-)]i, and thereby the polarity of γ-aminobutyric acid type A (GABAA) receptor signaling. The experimental procedures and results in this study are insufficient to support these conclusions. Contradictory results previously published by these authors and other laboratories are not referred to. PMID:25190788

  19. Radiation Transport

    Energy Technology Data Exchange (ETDEWEB)

    Urbatsch, Todd James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-06-15

    We present an overview of radiation transport, covering terminology, blackbody raditation, opacities, Boltzmann transport theory, approximations to the transport equation. Next we introduce several transport methods. We present a section on Caseology, observing transport boundary layers. We briefly broach topics of software development, including verification and validation, and we close with a section on high energy-density experiments that highlight and support radiation transport.

  20. Stability of atoms in the anionic domain (Z

    CERN Document Server

    Gil, G

    2013-01-01

    We study the stability and universal behaviour of the ionization energy of N-electron atoms with nuclear charge Z in the anionic domain (Zanionic instability threshold. As testing systems we choose inert gases (He-like, Ne-like and Ar-like isoelectronic sequences) and alkali metals (Li-like, Na-like, K-like sequences). From the results, it is apparent that, for inert gases case, the stability relation with N is completely inverted in the singly-charged anion region (Z=N-1) with respect to the neutral atom region (Z=N), i.e. larger systems are more stable than the smaller ones. We devised a semi-analytical model (inspired by the zero-range forces theory) which lead us to establish the ionization energy dependence on the nuclear charge n...

  1. Chemistry of nitrile anions in the interstellar medium

    International Nuclear Information System (INIS)

    Despite the extreme conditions of temperature (down to 10K) and density (down to 100 molecules/cm3), the giant molecular clouds and the circumstellar envelopes present a rich and complex chemistry. To date, more than 180 molecules have been detected in the InterStellar Medium (ISM) with a large abundance of nitriles (RC≡N). In addition, several anions have been recently observed in this medium: C4H¯, C6H¯, C8H¯, CN¯, C3N¯ and C5N¯. These last species should play a key role in the molecular growth towards complexity. To explore this hypothesis, their reactivity must be studied in the laboratory. The FALP-MS and the CRESU experimental apparatuses of the Rennes University are able to measure absolute rate coefficient of various chemical reactions, including the ion – molecule reactions, in gas phase at low temperature (from 300K for the FALP-MS down to 15K for the CRESU). Therefore, these experimental tools are particularly adapted to the kinetic studies of reactions potentially involved in the Interstellar Medium. One of the difficulties encountered in experiments with anions is their generation. We describe here the formation of the CN¯ and C3N¯ anions by dissociative electron attachment on the molecular precursors BrCN and BrC3N

  2. Fixing of metallic acetates on an anion-exchange resin

    International Nuclear Information System (INIS)

    After giving a brief review of the theoretical principles governing the fixation of anionic complexes of metallic elements on an anion exchange resin, we consider the particular case of uranyl acetate. By plotting the partition curves we have been able to calculate the exchange constants in the resin. By studying the changes in the logarithm of the limiting partition coefficient as a function of the logarithm of the free acetate ion concentration, it has been possible to calculate the dissociation constants for the complexes in solution. The fixation of a large number of metallic acetates has been studied. All the tests have been negative except in the case of mercury. For this reason we have been able to consider the possibility of separating uranium from a certain number of elements. Some of these separations are possible even in the presence of interfering anions such as chlorides which have a greater affinity for the resin than have the acetate ions. In the case of water-ethanol and water-isopropanol mixtures, we have improved the conditions under which copper acetate and mercury acetate may be fixed. This study has enabled us to calculate the dissociation constant for the CuAc3- complex in the mixtures water +40% (by weight) isopropanol and water +50% (by weight) isopropanol. It should also make it possible to use separation conditions which could not hitherto be applied in aqueous media. (author)

  3. An anionic antimicrobial peptide from toad Bombina maxima.

    Science.gov (United States)

    Lai, Ren; Liu, Hen; Hui Lee, Wen; Zhang, Yun

    2002-07-26

    Amphibian skin is a rich resource of antimicrobial peptides like maximins and maximins H from toad Bombina maxima. A novel cDNA clone encoding a precursor protein that comprises maximin 3 and a novel peptide, named maximin H5, was isolated from a skin cDNA library of B. maxima. The predicted primary structure of maximin H5 is ILGPVLGLVSDTLDDVLGIL-NH2. Containing three aspartate residues and no basic amino acid residues, maximin H5 is characterized by an anionic property. Different from cationic maximin H peptides, only Gram-positive strain Staphylococcus aureus was sensitive to maximin H5, while the other bacterial and fungal strains tested were resistant to it. The presence of metal ions, like Zn2+ and Mg2+, did not increase its antimicrobial potency. Maximin H5 represents the first example of potential anionic antimicrobial peptides from amphibians. The results provide the first evidence that, together with cationic antimicrobial peptides, anionic antimicrobial peptides may also exist naturally as part of the innate defense system. PMID:12127963

  4. Phosphate Removal by Anion Binding on Functionalized Nanoporous Sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Chouyyok, Wilaiwan; Wiacek, Robert J.; Pattamakomsan, Kanda; Sangvanich, Thanapon; Grudzien, Rafal M.; Fryxell, Glen E.; Yantasee, Wasanna

    2010-03-26

    Phosphate was captured from aqueous solutions by cationic metal-EDA complexes anchored inside mesoporous silica MCM-41 supports (Cu(II)-EDA-SAMMS and Fe(III)-EDA-SAMMS). Fe-EDA-SAMMS was more effective at capturing phosphate than the Cu-EDA-SAMMS and was further studied for matrix effects (e.g., pH, ionic strength, and competing anions) and sorption performance (e.g., capacity and rate). The adsorption of phosphate was highly pH dependent; it increased with increasing pH from 1.0 to 6.5, and decreased above pH 6.5. The adsorption was affected by high ionic strength (0.1 M of NaCl). In the presence of 1000-fold molar excess of chloride and nitrate anions, phosphate removal by Fe-EDA-SAMMS was not affected. Slight, moderate and large impacts were seen with bicarbonate, sulfate and citrate anions, respectively. The phosphate adsorption data on Fe-EDA-SAMMS agreed well with the Langmuir model with the estimated maximum capacity of 43.3 mg/g. The material displayed rapid sorption rate (99% of phosphate removal within 1 min) and lowering the phosphate content to ~ 10 µg/L of phosphorus, which is lower than the EPA’s established freshwater contaminant level for phosphorous (20 µg/L).

  5. Effect of Anion on Adsorption of Rare Earth Elements on Kaolinite

    Institute of Scientific and Technical Information of China (English)

    Wan Yingxin; Liu Jianjun

    2007-01-01

    For a better understanding the adsorption of rare earth elements (REEs) on minerals and its controlling factors, adsorption experiments were performed with kaolin in a matrix of various concentration of anion (Cl-, ClO4-, SO42-) in the pH 6.5. The adsorption of REEs onto the kaolin increase with increasing anion concentration, especially in the presence of SO42-, which is ascribe to the Na+ mass effect and anion complexation. furthermore, the heavy REEs are more adsorbed onto kaolin in presence of higher concentration of anion, especially for Cl- and SO42-, presumably due to the difference of anion complexation with light REE and heavy REEs.

  6. Electron exchange between dipole-bound anion and polar molecule and dipole-bound anions dimer formation

    International Nuclear Information System (INIS)

    We consider collision between a dipole-bound molecular anion and a neutral polar molecule and show that the excess electron can bind two neutral molecules into a dimer. Using a variational approach similar to the Heitler-London model of H''+2 ion we obtain the energy terms of such a dimer. Their difference determines the cross-section of electron transfer from the anion to the neutral molecule in quasiclassical near-resonant Born-Oppenheimer approximation. We obtain for the cross-section an analytic expression containing the weak (logarythmic) factor depending on the molecular dipole moment, and collision velocity. Our analytic calculations are in a good accordance with the results of a recent experiment.

  7. Chamber transport

    Energy Technology Data Exchange (ETDEWEB)

    OLSON,CRAIG L.

    2000-05-17

    Heavy ion beam transport through the containment chamber plays a crucial role in all heavy ion fusion (HIF) scenarios. Here, several parameters are used to characterize the operating space for HIF beams; transport modes are assessed in relation to evolving target/accelerator requirements; results of recent relevant experiments and simulations of HIF transport are summarized; and relevant instabilities are reviewed. All transport options still exist, including (1) vacuum ballistic transport, (2) neutralized ballistic transport, and (3) channel-like transport. Presently, the European HIF program favors vacuum ballistic transport, while the US HIF program favors neutralized ballistic transport with channel-like transport as an alternate approach. Further transport research is needed to clearly guide selection of the most attractive, integrated HIF system.

  8. A Simple Halide-to-Anion Exchange Method for Heteroaromatic Salts and Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Neus Mesquida

    2012-04-01

    Full Text Available A broad and simple method permitted halide ions in quaternary heteroaromatic and ammonium salts to be exchanged for a variety of anions using an anion exchange resin (A− form in non-aqueous media. The anion loading of the AER (OH− form was examined using two different anion sources, acids or ammonium salts, and changing the polarity of the solvents. The AER (A− form method in organic solvents was then applied to several quaternary heteroaromatic salts and ILs, and the anion exchange proceeded in excellent to quantitative yields, concomitantly removing halide impurities. Relying on the hydrophobicity of the targeted ion pair for the counteranion swap, organic solvents with variable polarity were used, such as CH3OH, CH3CN and the dipolar nonhydroxylic solvent mixture CH3CN:CH2Cl2 (3:7 and the anion exchange was equally successful with both lipophilic cations and anions.

  9. A fluorescent coumarin-thiophene hybrid as a ratiometric chemosensor for anions: Synthesis, photophysics, anion sensing and orbital interactions

    Science.gov (United States)

    Yanar, Ufuk; Babür, Banu; Pekyılmaz, Damla; Yahaya, Issah; Aydıner, Burcu; Dede, Yavuz; Seferoğlu, Zeynel

    2016-03-01

    A colorimetric and fluorimetric fluorescent chemosensor (CT-2), having a coumarin ring as a signaling unit and an acetamido thiophene ring as an H-donor receptor, has been synthesized from amino derivative (CT-1) of CT-2 for the purpose of recognition of anions in DMSO. The absorption and emission maxima were both determined for the fluorescent dye in different solvents. Both hypsochromic shift at the absorption maximum, and quenching of fluorescence after interactions between the anions and the receptoric part, were observed. This phenomenon was explained using orbital interactions based on quantum chemical calculations. The selectivity and sensitivity of CT-2 for F-, Cl-, Br-, I-, AcO-, CN-, H2PO4-, HSO4- and ClO4- anions were determined with spectrophotometric, fluorimetric and 1H NMR titration techniques and it was found that CT-2 be utilized for the detection of CN-, F- and AcO- in the presence of other ions as competitors. Color and fluorescence changes visible to the naked eye and under UV (365 nm) were observed upon addition of CN-, F- and AcO- to the solution of chemosensor (CT-2) in DMSO. The sensor showed no colorimetric and fluorimetric response for the anions such as Cl-, Br-, I-, H2PO4-, HSO4-, and ClO4-. However, 1H NMR titration shows that the chemosensor was more sensitive to CN-, than F- and AcO- at the stochiometric ratio of 1:2.5 respectively. Additionally, the compounds CT-1 and CT-2 showed good thermal stability for practical applications.

  10. Study of the simultaneous complexation of a cation and of an anion using functionalized calixarenes; Etude de la complexation simultanee d'un cation et d'un anion par des calixarenes fonctionnalises

    Energy Technology Data Exchange (ETDEWEB)

    Moli, Ch. [CEA Cadarache, Dept. d' Etudes des Dechets, DED, 13 - Saint Paul lez Durance (France)]|[Universite Louis Pasteur, 67 - Strasbourg (France)

    2002-03-01

    The chemical reprocessing of irradiated nuclear fuels leads to the production of high-level radioactive liquid wastes which contain long-lived toxic radioelements. In the framework of the long-term management of these wastes, important research work is carried out for the separation of these radioelements for their further transmutation or immobilization inside specific matrices. These radioelements are present in acid solutions of fission products in the form of cations (cesium), anions (technetium, selenium) and molecules (iodine). Crown calixarenes have been successfully used for the extraction of cesium thanks to their exceptional selectivities. This work is mainly based on the use of the chelating properties of calixarenes for the extraction of anionic radioelements. Calixarenes functionalized by amino-carbon chains have been selected. The synthesis of amine calix[4]arenes and calix[6]arenes is described and their extractive and ionophoretic properties with respect to radioelements are shown using aqueous selective separation techniques like the liquid-liquid extraction and the supported liquid membrane transport. Technetium and selenium are extracted by amine calixarenes from a 10{sup -2} M aqueous solution of nitric acid. At this acidity, no selenium transport is observed, while technetium transport is efficient: the solution is quasi-totally decontaminated in 6 hours. Molecular iodine is efficiently extracted with a simple organic diluent, the 1,2-nitro-phenyl-hexyl-ether, from a strongly concentrated aqueous solution of nitric acid (HNO{sub 3} = 3 M). The transport of iodine becomes faster and more efficient when its concentration in the solution is higher. (J.S.)

  11. The role of the symmetry and the flexibility of the anion on the characteristics of the nanostructures and the viscosities of ionic liquids☆

    Institute of Scientific and Technical Information of China (English)

    Jianguang Qi; Yufeng Hu; Yamei Zhao; Jiguang Li

    2015-01-01

    The transport properties of ionic liquids (ILs) are crucial properties in view of their applications in electrochem-ical devices. One of the most important advantages of ILs is that their chemical–physical properties and conse-quently their bulk performances can be well tuned by optimizing the chemical structures of their ions. This will require elucidating the structural features of the ions that fundamentally determine the characteristics of the nanostructures and the viscosities of ILs. Here we showed for the first time that the“rigidity”, the order, and the compactness of the three-dimensional ionic networks generated by the anions and the cation head groups determine the formation and the sizes of the nanostructures in the apolar domains of ILs. We also found that the properties of ionic networks are governed by the conformational flexibility and the symmetry of the anion and/or the cation head group. The thermal stability of the nanostructures of ILs was shown to be con-trolled by the sensitivity of the conformational equilibrium of the anion to the change of temperature. We showed that the viscosity of ILs is strongly related to the symmetry and the flexibility of the constitute ions rather than to the size of the nanostructures of ILs. Therefore, the characteristics of the nanostructures and the viscosities of ILs, especially the thermal stability of the nanostructures, can be fine-tuned by tailoring the symmetry and the conformational flexibility of the anion.

  12. Biogeochemical behaviour of anionic radionuclides in soil: evidence for biotic interactions

    International Nuclear Information System (INIS)

    Among studies on radionuclides, very few have been devoted to the behaviour of long-lived anionic radionuclides as 99Tc and 79Se in soils. Yet these two species are supposed to be highly mobile in soils, because of their anionic forms. The understanding of their biogeochemical behaviour in soils will improve both the ecological and health risk assessment. Very often the interactions between the radionuclides and the different components of soil are considered only from a physico-chemical point of view. However in surface horizons and more specially in the rhizosphere, the micro-organisms can not be ignored as they can affect either directly or indirectly the speciation of most of the chemical species, and particularly these of Se and Tc. This study demonstrates the role of the microbial compartment in the retention of Se and Tc in soil by comparing experiments with a sterilized soil (no microbial activity) to experiments with a soil more or less amended with organic carbon and / or nitrate, to stimulate its microbial activity. Kd coefficients for Se and Tc were determined in batch experiments, whereas transport of Se and Tc was investigated through column leaching experiments. Kd for Se was enhanced for the natural soil without amendment compared to the value obtained for the sterilized soil. The retention of Se was higher again in the natural soil amended with glucose and nitrate together. In addition, these amendments facilitated the development of a biofilm at the entrance of the column, which can directly retain Se. This effect was less obvious for Tc in batch experiments, but was revealed by leaching experiments where a high quantity of Tc was retained in the soil column when added with glucose and nitrate. These results give evidence that micro-organisms are responsible for a greater retention of Se and Tc in soil. (author)

  13. Molecular physiology and genetics of Na+-independent SLC4 anion exchangers

    Science.gov (United States)

    Alper, Seth L.

    2009-01-01

    Summary Plasmalemmal Cl–/HCO3– exchangers are encoded by the SLC4 and SLC26 gene superfamilies, and function to regulate intracellular pH, [Cl–] and cell volume. The Cl–/HCO3– exchangers of polarized epithelial cells also contribute to transepithelial secretion and reabsorption of acid–base equivalents and Cl–. This review focuses on Na+-independent electroneutral Cl–/HCO3– exchangers of the SLC4 family. Human SLC4A1/AE1 mutations cause the familial erythroid disorders of spherocytic anemia, stomatocytic anemia and ovalocytosis. A largely discrete set of AE1 mutations causes familial distal renal tubular acidosis. The Slc4a2/Ae2–/– mouse dies before weaning with achlorhydria and osteopetrosis. A hypomorphic Ae2–/– mouse survives to exhibit male infertility with defective spermatogenesis and a syndrome resembling primary biliary cirrhosis. A human SLC4A3/AE3 polymorphism is associated with seizure disorder, and the Ae3–/– mouse has increased seizure susceptibility. The transport mechanism of mammalian SLC4/AE polypeptides is that of electroneutral Cl–/anion exchange, but trout erythroid Ae1 also mediates Cl– conductance. Erythroid Ae1 may mediate the DIDS-sensitive Cl– conductance of mammalian erythrocytes, and, with a single missense mutation, can mediate electrogenic SO42–/Cl– exchange. AE1 trafficking in polarized cells is regulated by phosphorylation and by interaction with other proteins. AE2 exhibits isoform-specific patterns of acute inhibition by acidic intracellular pH and independently by acidic extracellular pH. In contrast, AE2 is activated by hypertonicity and, in a pH-independent manner, by ammonium and by hypertonicity. A growing body of structure–function and interaction data, together with emerging information about physiological function and structure, is advancing our understanding of SLC4 anion exchangers. PMID:19448077

  14. Imidazolium-Based Polymeric Materials as Alkaline Anion-Exchange Fuel Cell Membranes

    Science.gov (United States)

    Narayan, Sri R.; Yen, Shiao-Ping S.; Reddy, Prakash V.; Nair, Nanditha

    2012-01-01

    Polymer electrolyte membranes that conduct hydroxide ions have potential use in fuel cells. A variety of polystyrene-based quaternary ammonium hydroxides have been reported as anion exchange fuel cell membranes. However, the hydrolytic stability and conductivity of the commercially available membranes are not adequate to meet the requirements of fuel cell applications. When compared with commercially available membranes, polystyrene-imidazolium alkaline membrane electrolytes are more stable and more highly conducting. At the time of this reporting, this has been the first such usage for imidazolium-based polymeric materials for fuel cells. Imidazolium salts are known to be electrochemically stable over wide potential ranges. By controlling the relative ratio of imidazolium groups in polystyrene-imidazolium salts, their physiochemical properties could be modulated. Alkaline anion exchange membranes based on polystyrene-imidazolium hydroxide materials have been developed. The first step was to synthesize the poly(styrene-co-(1-((4-vinyl)methyl)-3- methylimidazolium) chloride through a free-radical polymerization. Casting of this material followed by in situ treatment of the membranes with sodium hydroxide solutions provided the corresponding hydroxide salts. Various ratios of the monomers 4-chloromoethylvinylbenzine (CMVB) and vinylbenzine (VB) provided various compositions of the polymer. The preferred material, due to the relative ease of casting the film, and its relatively low hygroscopic nature, was a 2:1 ratio of CMVB to VB. Testing confirmed that at room temperature, the new membranes outperformed commercially available membranes by a large margin. With fuel cells now in use at NASA and in transportation, and with defense potential, any improvement to fuel cell efficiency is a significant development.

  15. Primary structure of a sperm cell anion exchanger and its messenger ribonucleic acid expression during spermatogenesis.

    Science.gov (United States)

    Holappa, K; Mustonen, M; Parvinen, M; Vihko, P; Rajaniemi, H; Kellokumpu, S

    1999-10-01

    Chloride/bicarbonate (Cl-/HCO(3)-) exchangers are a family of proteins (anion exchanger [AE] gene family) that regulate many vital cellular processes such as intracellular pH, cell volume, and Cl- concentration. They may also be involved in the regulation of sperm cell motility and acrosome reaction during fertilization, as these two phenomena are bicarbonate dependent, and we have previously shown that a polypeptide immunologically related to erythrocyte band 3 is expressed in mammalian sperm cells. We have now identified this putative sperm cell anion exchanger as the AE2 isoform of this gene family. First, we determined its complete primary structure from the human testis lambda gt 11 cDNA library. The cloned sequence was found to consist of 3896 base pairs (bp) with an open reading frame of 3726 bp, and to be almost identical to the previously published human genomic AE2 sequence. Only four amino acid disparities were found between these two sequences. Second, our in situ hybridization analyses showed that AE2 mRNA is expressed in developing sperm cells, indicating that the cloned sequence corresponds to the sperm cell AE. Our reverse transcription-polymerase chain reaction analyses suggested further that the expression of AE2 mRNA was variable to some extent during the epithelial cell cycle. Strongest expression was observed at stages VII-XIV except for stage X, i.e., when major structural and morphological changes take place. These results suggest that the full-length AE2 isoform regulates HCO(3)- transport in mature sperm cells and thus their motility in vivo. PMID:10491633

  16. Modelling the effective diffusion coefficient of anions in Callovo-Oxfordian argillite knowing the microstructure of the rock

    International Nuclear Information System (INIS)

    After having presented the issue of radioactive waste storage, the concept of geological storage and its application in the Meuse/Haute-Marne underground laboratory, and described the Callovo-Oxfordian geological formation and the argillite transport properties, this research thesis aims at developing a prediction of these properties at a macroscopic scale for water and anions. A first part presents the different experimental means implemented to acquire the diffusion coefficients for the studied materials (Callovo-Oxfordian argillite and purified Puy illite), and the spatial organisation of minerals by LIBS probe-based mapping to highlight a relationship between rock microstructure and its transport macroscopic properties. The next part presents the models which have been developed at the nanometer and micrometre scale to predict the diffusion coefficients. Experimental results are then compared with computed values

  17. Sustainable Transportation

    DEFF Research Database (Denmark)

    Hall, Ralph P.; Gudmundsson, Henrik; Marsden, Greg;

    2014-01-01

    that relate to the construction and maintenance of transportation infrastructure and the operation or use of the different transportation modes. The concept of sustainable transportation emerged in response to these concerns as part of the broader notion of sustainable development. Given the...... transportation sector’s significant contribution to global challenges such as climate change, it is often said that sustainable development cannot be achieved without sustainable transportation....

  18. Treatment of tyramine-induced brain edema with anion transport inhibitor L-644,711

    International Nuclear Information System (INIS)

    Tyramine induces coma in phenelzine-treated dogs. Development of coma in these animals is associated with brain edema, abnormal brain scans of Tc-99m-diethylene-triamine-penta-acetic acid (Tc-99m-DTPA), and elevated levels of CSF catecholamines. We found that the intravenous administration of 6-7 mg/kg of a single dose of L-644,711 given fifteen minutes after the oral administration of tyramine to phenelzine-pretreated animals followed by an infusion of normal saline containing 6-7 mg/kg of the drug given over a period of 2 hr caused reversal of brain injury. This was accompanied by full recovery within a period of 24 hr of all the animals tested. A follow-up study revealed that 24 hr after treatment with L-644,711 CSF levels of catecholamines and brain images of Tc-99m-DTPA were indistinguishable from normal controls. Animals that received no drug died from unresolved coma within 4 to 24 hr. Animals that had recovered due to therapy with L-644,711 were given 10-14 days rest followed by a repetition of the phenelzine and tyramine treatment but denied L-644,711 therapy. These animals also died of unresolved coma within 24 hr. This preliminary study suggest that the use of L-644,711 may constitute an important advance in treatment of brain edema of a wide range of neurological disorders

  19. ASSESSMENT OF ANIONIC SURFACTANT-TRICHLOROETHYLENE MICROEMULSION STABILITY DURING TRANSPORT THROUGH QUARTZ SEDIMENT. (R826650)

    Science.gov (United States)

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

  20. Targeting Organic Anion Transporter 3 with Probenecid as a Novel Anti-Influenza A Virus Strategy

    OpenAIRE

    Perwitasari, Olivia; Yan, Xiuzhen; Johnson, Scott; White, Caleb; Brooks, Paula; Tompkins, S. Mark; Tripp, Ralph A.

    2013-01-01

    Influenza A virus infection is a major global health concern causing significant mortality, morbidity, and economic loss. Antiviral chemotherapeutics that target influenza A virus are available; however, rapid emergence of drug-resistant strains has been reported. Consequently, there is a burgeoning need to identify novel anti-influenza A drugs, particularly those that target host gene products required for virus replication, to reduce the likelihood of drug resistance. In this study, a small...

  1. Anionic species transport through the soil (Electromigration versus Electroosmosis): The case of EDTA

    OpenAIRE

    García Rubio, Ana; Villén Guzmán, María; Paz García, José Manuel; Gómez-Lahoz, C.; García Herruzo, Francisco; Rodríguez Maroto, José Miguel

    2014-01-01

    The use of EDTA as a complexing agent to extract metals from soil is common. We have tested this possibility for the remediation feasibility studies of a soil contaminated with lead, collected in the mining district of Linares (Spain), a region where the mining activity has been going on for more than 20 centuries. In this work, we have found that close to 100% of Pb is removed from the contaminated soil when EDTA is used in batch reactor experiments. However, almost no Pb is removed when ...

  2. Macrophages possess probenecid-inhibitable organic anion transporters that remove fluorescent dyes from the cytoplasmic matrix

    OpenAIRE

    1987-01-01

    We introduced several membrane-impermeant fluorescent dyes, including Lucifer Yellow, carboxyfluorescein, and fura-2, into the cytoplasmic matrix of J774 cells and thioglycollate-elicited mouse peritoneal macrophages by ATP permeabilization of the plasma membrane and observed the subsequent fate of these dyes. The dyes did not remain within the cytoplasmic matrix; instead they were sequestered within phase-lucent cytoplasmic vacuoles and released into the extracellular medium. We used Lucifer...

  3. Carbon dioxide transport in alligator blood and its erythrocyte permeability to anions and water

    DEFF Research Database (Denmark)

    Jensen, F B; Wang, T; Jones, D R;

    1998-01-01

    Deoxygenation of alligator red blood cells (RBCs) caused binding of two HCO3- equivalents per hemoglobin (Hb) tetramer at physiological pH. At lowered pH, some HCO3- binding also occurred to oxygenated Hb. The erythrocytic total CO2 content was large, and Hb-bound HCO3-, free HCO3-, and carbamate...

  4. M8L12 cubic cages with all facial Δ or facial Λ configuration: effects of surface anions on the occupancy of the cage and anion exchange.

    Science.gov (United States)

    Yang, Jing; Chang, Xiao-Yong; Sham, Kiu-Chor; Yiu, Shek-Man; Kwong, Hoi-Lun; Che, Chi-Ming

    2016-05-21

    M8L12 cubic cages (M = Mn(II), Zn(II) or Cd(II)), with all eight metal ions having all facial Δ or facial Λ configurations and having an encapsulated anion, were prepared by the self-assembly of m-xylene-bridged imidazolyl-imine ligands and MX2 (X = PF6(-), SbF6(-), TfO(-)) salts; the encapsulated anion exchange with different anions (SbF6(-), Tf2N(-), NO3(-), TsO(-)) was studied and the results with NO3(-) and TsO(-) indicate that anions on the cage surfaces affect the encapsulated anion exchange and the occupancy of the cage. PMID:27064122

  5. Report membrane transport of lactic acid in the filamentous fungus Rhizopus

    Science.gov (United States)

    The fungus Rhizopus is frequently used for fermentative production of lactic acid, but little is known about the mechanisms or proteins for transporting this carboxylic acid. Since transport of the lactate anion across the plasma membrane is critical to prevent acidification of the cytoplasm, we ev...

  6. Transport of thyroid hormones is selectively inhibited by 3-iodothyronamine

    OpenAIRE

    Ianculescu, Alexandra G.; Friesema, Edith C.H.; Visser, Theo J; Giacomini, Kathleen M.; Scanlan, Thomas S.

    2010-01-01

    Thyroid hormone transporters are responsible for the cellular uptake of thyroid hormones, which is a prerequisite for their subsequent metabolism and action at nuclear thyroid hormone receptors. A recently discovered thyroid hormone derivative, 3-iodothyronamine (T1AM), has distinct biological effects that are opposite those of thyroid hormone. Here we investigate the effects of T1AM on thyroid hormone transporters using COS-1 cells transfected with the multispecific organic anion transportin...

  7. Solvation of benzophenone anion radical in ethanol and ethanol/2-methyltetrahydrofuran mixture

    International Nuclear Information System (INIS)

    The electron spin-echo modulations and the absoprtion spectra of benzophenone anion radicals generated by γ-irradiation in the glassy matrices of ethanol and ethanol2-methyltetrahydrofuran mixtures have been measured for elucidating the mechanism of spectral shift observed during the solvation of the anion radicals in alcohols. The anion radical generated at 4.2 K in the ethanol matrix maintains the same solvation structure as that of neutral benzophenone. At 77 K ethanol molecules solvate the anion radical by orienting the O-H dipoles toward the anion radical. The anion radical is hydrogen-bonded by two ethanol molecules through the p/sub z/ orbital on the benzophenone oxygen which composes the π orbitals of anion radical. Three kinds of anion radicals are observed in the mixed matrix at 77 K. Two of them are essentially the same as those observed in the ethanol matrix at 4.2 and 77 K. The third has the absorption maximum at 700 nm and is attributed to the anion radical hydrogen-bonded by one ethanol molecule through the p/sub z/ orbital. It is concluded that the spectral shift observed in alcohols is caused by the stabilization of a SOMO π* orbital induced by the hydrogen bonding with the (RO)H--O--H(OR) angle perpendicular to the molecular plane of the anion radical

  8. Adsorption and desorption dynamics of citric acid anions in soil

    KAUST Repository

    Oburger, E.

    2011-07-26

    The functional role of organic acid anions in soil has been intensively investigated, with special focus on (i) microbial respiration and soil carbon dynamics, (ii) nutrient solubilization or (iii) metal detoxification and reduction of plant metal uptake. Little is known about the interaction dynamics of organic acid anions with the soil matrix and the potential impact of adsorption and desorption processes on the functional significance of these effects. The aim of this study was to characterize experimentally the adsorption and desorption dynamics of organic acid anions in five agricultural soils differing in iron and aluminium oxide contents and using citrate as a model carboxylate. Results showed that both adsorption and desorption processes were fast in all soils, reaching a steady state within approximately 1 hour. However, for a given total soil citrate concentration (ct) the steady state was critically dependent on the starting conditions of the experiment, whether most of the citrate was initially present in solution (cl) or held on the solid phase (cs). Specifically, desorption-led processes resulted in significantly smaller steady-state solution concentrations than adsorption-led processes, indicating that hysteresis occurred. As it is not possible to distinguish between different adsorption and desorption pools in soil experimentally, a new dynamic hysteresis model that relies only on measured soil solution concentrations was developed. The model satisfactorily explained experimental data and was able to predict dynamic adsorption and desorption behaviour. To demonstrate its use, we applied the model to two relevant situations involving exudation and microbial degradation. The study highlighted the complex nature of citrate adsorption and desorption dynamics in soil. We conclude that existing models need to incorporate both temporal and hysteresis components to describe realistically the role and fate of organic acids in soil processes. © 2011 The

  9. Chemistry of nitrile anions in the interstellar medium

    Energy Technology Data Exchange (ETDEWEB)

    Carles, S.; Le Garrec, J.-L.; Biennier, L. [Institut de Physique de Rennes, Département de Physique Moléculaire, Astrophysique de Laboratoire, UMR CNRS 6251, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex (France); Guillemin, J.-C. [Institut des Sciences Chimiques de Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837,35708 Rennes Cedex 7 (France)

    2015-12-31

    Despite the extreme conditions of temperature (down to 10K) and density (down to 100 molecules/cm{sup 3}), the giant molecular clouds and the circumstellar envelopes present a rich and complex chemistry. To date, more than 180 molecules have been detected in the InterStellar Medium (ISM) with a large abundance of nitriles (RC≡N). In addition, several anions have been recently observed in this medium: C{sub 4}H{sup ¯}, C{sub 6}H{sup ¯}, C{sub 8}H{sup ¯}, CN{sup ¯}, C{sub 3}N{sup ¯} and C{sub 5}N{sup ¯}. These last species should play a key role in the molecular growth towards complexity. To explore this hypothesis, their reactivity must be studied in the laboratory. The FALP-MS and the CRESU experimental apparatuses of the Rennes University are able to measure absolute rate coefficient of various chemical reactions, including the ion – molecule reactions, in gas phase at low temperature (from 300K for the FALP-MS down to 15K for the CRESU). Therefore, these experimental tools are particularly adapted to the kinetic studies of reactions potentially involved in the Interstellar Medium. One of the difficulties encountered in experiments with anions is their generation. We describe here the formation of the CN{sup ¯} and C{sub 3}N{sup ¯} anions by dissociative electron attachment on the molecular precursors BrCN and BrC{sub 3}N.

  10. Natural minerals and synthetic materials for sorption of radioactive anions

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Mun Ja; Chun, Kwan Sik; Kim, Seung Soo

    1998-07-01

    Technetium-99 and iodine-129 are fission products with long half-lives, and exist as highly soluble anionic species. Studies on natural and synthetic materials sorbing TcO{sub 4} and/or I have been performed by several researchers. The application of these materials as an additive in the high-level waste disposal has been considered. The iron- or sulfide-containing minerals such as metal iron, iron powder, stibnite and pyrrhotite show a high capacity for TcO{sub 4} sorption. And the small amounts of activated carbon are reported to have high distribution coefficients recently. In the iodine sorption studies, sulfide-, copper-, lead- or mercury-containing minerals can be a candidate. Pyrite, chalcopyrite, galena, Cu{sub 2}S and CuS reveal a high capacity for I sorption. The synthetic materials were found to have high sorption capacity and compensate the defects of natural minerals, which contain hydrous oxides such as zirconium oxide, aluminium oxide and mercarbide. The mercarbide has the high distribution coefficients for the sorption of TcO{sub 4} and I. Recently it was proposed that the synthetic clay, hydrotalcite, could be useful for the fixation of anion. However, to determine the applicability of those natural and synthetic materials as an additive to a buffer or backfill material for sorption of TcO{sub 4} and/or I, the sorption behavior of the anions on those materials under the repository conditions should be identified. (author). 32 refs., 21 tabs., 10 figs

  11. Anion Photoelectron Spectroscopy of NbW- and W2-

    Science.gov (United States)

    Schnepper, D. Alex; Baudhuin, Melissa A.; Leopold, Doreen; Casey, Sean M.

    2015-06-01

    The 488 nm vibrationally-resolved photoelectron spectra of NbW- and W2- are reported. The electron affinity of W2 ( 1σg+ ← 2σu+ ) is found to be 1.118 ± 0.007 eV, which differs from the value reported in a previous anion photoelectron spectroscopic study of W2- (1.46 eV), but was accurately predicted by density functional calculations (1.12 eV). The fundamental vibrational frequency of W2 is measured to be 345 ± 15 wn, in agreement with the value previously reported in matrix resonance Raman studies (337 wn). The W2- anion is measured to have a fundamental frequency of 320 ± 15 wn. Several weak transitions to excited electronic states are seen and tentatively assigned based on calculated energies. NbW has an electron affinity of 0.856 ± 0.007 eV. Vibrational frequencies are found, by Franck-Condon fitting of overlapping transitions, to be 365 ± 20 cm-1 for NbW- and 410 ± 20 cm-1 for NbW. This increase in vibrational frequency upon photodetachment suggests that the extra electron is in an antibonding orbital, leading to ground state assignments of 3Δ and 2Δ for the anion and neutral, respectively. These results are compared to those obtained for other Group V and Group VI transition metal dimers and trends are discussed. H. Weidele et al., Chem. Phys. Lett. 237 (1995) 425-431 Z. J. Wu, X. F. Ma, Chem. Phys. Lett. 371 (2003) 35-39 Z. Hu, J.-G. Dong, J. R. Lombardi, D. M. Lindsay, J. Chem. Phys. 97 (1992) 8811-8812

  12. Understanding anionic Chugaev elimination in pericyclic tetracene formation

    OpenAIRE

    Burroughs, Laurence; Ritchie, John; Woodward, Simon

    2016-01-01

    The reaction pathway for the formation of tetracenes from the diols 1,2-C6H4(CHOHC≡CAr)2 , LiHDMS, CS2 and MeI has been modelled by computational methods at the CBS-QB3 level of theory. Comparison of PhCHOC(=S)YCCPh (Y = S- or SMe) indicates a slight kinetic advantage for the anionic system towards [3,3]-sigmatropic rearrangement [Eact(calc.) 19.7 vs 21.8 kcal mol-1]. Using anthracene-based models, 10-{SC(=O)Y}-4a,10-dihydroanthracene (Y = S- or SMe), allows direct comparison of both syn and...

  13. Fixation of metallic sulfosalicylate complexes on an anionic exchange resin

    International Nuclear Information System (INIS)

    Since sulfosalicylate ions have acid-base properties, sulfosalicylate complexes have an apparent stability which varies with the ph. As a result, the fixation of sulfo-salicylates on an anionic exchange resin depends on the ph of the solution in equilibrium with the resin. This research has been aimed at studying the influence of the ph on the fixation on an anionic exchange resin (Dowex 1 x 4) of sulfosalicylate anions on the one hand, and of metallic sulfosalicylate complexes on the other hand. In the first part of this work, a determination has been made, by frontal analysis of the distribution of sulfosalicylate ions in the resin according to the total sulfosalicylate I concentration in the aqueous solution in equilibrium with the resin. The exchange constants of these ions between the resin and the solution have been calculated. In the second part, a study has been made of the fixation of anionic sulfosalicylate complexes of Fe(III), Al(III), Cr(III), Cu(II), Ni(II), Co(II), Zn(II), Mn(II), Cd(II), Fe(II) and UO22+. By measuring the partition coefficients of these different elements between the resin and the solution it has been possible to give interpretation for the modes of fixation of the metallic ions, and to calculate their exchange constant between the resin and the solution. The relationship has been established for each metallic element studied, between its partition coefficient, the ph and the total concentration of the complexing agent in solution. Such a relationship makes it possible to predict, for given conditions, the nature of the species in solution and in the resin, as well as the partition coefficient of a metallic, element. Finally, in the third part of the work, use has been made of results obtained previously, to carry out some separations (Ni2+ - Co2+; Ni2+ - Co2+ - Cu2+; UO22+ - Fe3+; UO22+ - Cr3+; UO22+ - Cu2+; UO22+ - Ni2+; UO22+ - Co2+; UO22+ - Mn2+ and UO22+ - Cd2+), as well as the purification of a uranyl sulfosalicylate solution

  14. Ionic conductivity in crystal structures with isolated tetragonal anions

    International Nuclear Information System (INIS)

    A unique peculiarity - the presence of complex isolated tetrahedron anions TZK4(4y-Z), where K - oxygen or Hal atom, y - its valency, Z - T element valency, is showh to be characteristic for different groups of superionic conductors including complex oxides of zirconium, scandium and molybdenum. It is possible to integrate and systematize a large number of ionic conductors on the basis of the given peculiarities of the crystal structure. Such an approach allows to consider the structure and electrophysical properties of a great number of cation conductors on the common ground, and to mark the concrete ways for searching new ion conducting materials

  15. Quasichemical and structural analysis of polarizable anion hydration

    Science.gov (United States)

    Rogers, David M.; Beck, Thomas L.

    2010-01-01

    Quasichemical theory is utilized to analyze the relative roles of solute polarization and size in determining the structure and thermodynamics of bulk anion hydration for the Hofmeister series Cl-, Br-, and I-. Excellent agreement with experiment is obtained for whole salt hydration free energies using the polarizable AMOEBA force field. The total hydration free energies display a stronger dependence on ion size than on polarizability. The quasichemical approach exactly partitions the solvation free energy into inner-shell, outer-shell packing, and outer-shell long-ranged contributions by means of a hard-sphere condition. The inner-shell contribution becomes slightly more favorable with increasing ion polarizability, indicating electrostriction of the nearby waters. Small conditioning radii, even well inside the first maximum of the ion-water(oxygen) radial distribution function, result in Gaussian behavior for the long-ranged contribution that dominates the ion hydration free energy. This in turn allows for a mean-field treatment of the long-ranged contribution, leading to a natural division into first-order electrostatic, induction, and van der Waals terms. The induction piece exhibits the strongest ion polarizability dependence, while the larger-magnitude first-order electrostatic piece yields an opposing but weaker polarizability dependence. The van der Waals piece is small and positive, and it displays a small ion specificity. The sum of the inner-shell, packing, and long-ranged van der Waals contributions exhibits little variation along the anion series for the chosen conditioning radii, targeting electrostatic effects (influenced by ion size) as the largest determinant of specificity. In addition, a structural analysis is performed to examine the solvation anisotropy around the anions. As opposed to the hydration free energies, the solvation anisotropy depends more on ion polarizability than on ion size: increased polarizability leads to increased anisotropy

  16. Separation of boron isotopes using NMG type anion exchange resin

    International Nuclear Information System (INIS)

    Ion exchange separation of boron isotopes (B-10 and B-11) has been studied by using a special boron selective ion exchange resin; NMG (n-methyl glucamine)-type anion exchange resin. The resin has shown a large isotope separation coefficient of 1.02 at the experimental conditions of temperature, 80degC, and boric acid concentration, 0.2 M (mole/dm3). Enriched B-10 (92%) was obtained after the migration of 1149 m by a recyclic operation of ion exchange columns in a merry-go-round method. (author)

  17. On the Adsorption of Some Anionic Collectors on Fluoride Minerals

    DEFF Research Database (Denmark)

    Sørensen, Emil

    1973-01-01

    Test flotations have been carried out in a small apparatus under standardized conditions in order to determine the dependence of the flotation yield on the reagent concentration for certain minerals and anionic collectors. The results suggest that a special adsorption mechanism is operating in th...... case of fluoride minerals, and a theory is presented which involves the joint action of ionic and hydrogen bonds. A precondition is the compatibility of the crystal geometry with the configuration of the polar group of the collector molecules....

  18. Quasichemical and structural analysis of polarizable anion hydration.

    Science.gov (United States)

    Rogers, David M; Beck, Thomas L

    2010-01-01

    Quasichemical theory is utilized to analyze the relative roles of solute polarization and size in determining the structure and thermodynamics of bulk anion hydration for the Hofmeister series Cl(-), Br(-), and I(-). Excellent agreement with experiment is obtained for whole salt hydration free energies using the polarizable AMOEBA force field. The total hydration free energies display a stronger dependence on ion size than on polarizability. The quasichemical approach exactly partitions the solvation free energy into inner-shell, outer-shell packing, and outer-shell long-ranged contributions by means of a hard-sphere condition. The inner-shell contribution becomes slightly more favorable with increasing ion polarizability, indicating electrostriction of the nearby waters. Small conditioning radii, even well inside the first maximum of the ion-water(oxygen) radial distribution function, result in Gaussian behavior for the long-ranged contribution that dominates the ion hydration free energy. This in turn allows for a mean-field treatment of the long-ranged contribution, leading to a natural division into first-order electrostatic, induction, and van der Waals terms. The induction piece exhibits the strongest ion polarizability dependence, while the larger-magnitude first-order electrostatic piece yields an opposing but weaker polarizability dependence. The van der Waals piece is small and positive, and it displays a small ion specificity. The sum of the inner-shell, packing, and long-ranged van der Waals contributions exhibits little variation along the anion series for the chosen conditioning radii, targeting electrostatic effects (influenced by ion size) as the largest determinant of specificity. In addition, a structural analysis is performed to examine the solvation anisotropy around the anions. As opposed to the hydration free energies, the solvation anisotropy depends more on ion polarizability than on ion size: increased polarizability leads to increased

  19. Minority anion substitution by Ni in ZnO

    CERN Document Server

    Pereira, Lino Miguel da Costa; Correia, João Guilherme; Amorim, Lígia Marina; Silva, Daniel José; David-Bosne, Eric; Decoster, Stefan; da Silva, Manuel Ribeiro; Temst, Kristiaan; Vantomme, André

    2013-01-01

    We report on the lattice location of implanted Ni in ZnO using the $\\beta$− emission channeling technique. In addition to the majority substituting for the cation (Zn), a significant fraction of the Ni atoms occupy anion (O) sites. Since Ni is chemically more similar to Zn than it is to O, the observed O substitution is rather puzzling. We discuss these findings with respect to the general understanding of lattice location of dopants in compound semiconductors. In particular, we discuss potential implications on the magnetic behavior of transition metal doped dilute magnetic semiconductors.

  20. Diffusion, sorption, and retardation processes of anions in bentonite and organo-bentonites for multibarrier systems

    Science.gov (United States)

    Schampera, Birgit; Dultz, Stefan

    2013-04-01

    The low permeability, high cation exchange capacity (CEC) and plasticity of bentonites favor their use in multibarrier systems of waste deposits [1]. Bentonites have a high CEC but their ability to sorb anions is very low. There is, however, need for retardation of anions and organic pollutants in many applications. Bentonites, modified with certain organic cations, have the capacity to sorb anions and non-polar organic compounds in addition to cations. Investigations on organically modified clays address a wide variety of applications including immobilization of pollutants in contaminated soils, waste water treatment and in situ placement for the protection of ground water [2]. Many experiments on anion and cation sorption of organo-clays were conducted in the batch mode which does not reflect solid-liquid ratios and material densities in barrier systems. Diffusion experiments on compacted clays allow the evaluation of transport processes and sorption of pollutants at conditions relevant for repositories. For organo-clays only few diffusion studies are published e.g. [3] measured the diffusion of tritium and [4] the diffusion of H2O in bentonite and organo-bentonites. The organic cation hexadecylpyridinium (HDPy) was added to Wyoming bentonite (MX-80) in amounts corresponding to 2-400 % of the CEC. The uptake of organic cations was determined by the C-content, XRD and IR-spectroscopy. Wettability was analyzed by the contact angle. Physical, chemical and mineralogical properties of clays were characterized. Diffusion experiments were carried out in situ in a cell attached to the ATR-unit of a FTIR-spectrometer. For H2O-diffusion the compacted organo-clays are saturated first with D2O, afterwards H2O is supplied to the surface at the top of the clay platelet. Anion-diffusion was conducted with NO3--solution instead of H2O only having characteristic IR band positions at 1350 cm-1. Three different concentrations (0.25M, 0.5M and 1M) were used. Additional batch

  1. Zn-Al LAYERED DOUBLE HYDROXIDE PILLARED BY DIFFERENT DICARBOXYLATE ANIONS

    Directory of Open Access Journals (Sweden)

    S. Gago

    2004-12-01

    Full Text Available Zn-Al layered double hydroxides (LDHs intercalated by terephthalate (TPH and biphenyl-4,4'-dicarboxylate (BPH anions have been synthesized by direct co-precipitation from aqueous solution. The Zn/Al ratio in the final materials was 1.8. The products were characterized by powder X-ray diffraction, thermogravimetric analysis, FTIR and FT Raman spectroscopy, and MAS NMR spectroscopy. The basal spacing for the TPH-LDH intercalate was 14.62 Å, indicating that the guest anions stack to form a monolayer with the aromatic rings perpendicular to the host layers. For the LDH intercalate containing BPH anions, a basal spacing of at least 19.2 Å would be expected if the anions adopted an arrangement similar to that for the TPH anions. The observed spacing was 18.24 Å, suggesting that the anions are tilted slightly with respect to the host layers.

  2. Investigation of Polyacrylate Anion-Exchangers for Separation of Rare Earth Element Complexes with EDTA

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The rare earth complexes with EDTA, Ln(edta), show an unusual sequence of affinity for the anion-exchangers. The sorption and chromatographic separation of Y3+ for Nd3+ complexes with EDTA was studied by using the strongly basic gel and macroporous polyacrylate anion-exchangers, Amberlite IRA 458 and Amberlite 958, and the weakly basic gel polyacrylate anion-exchanger, Amberlite IRA-68. The investigations on sorption and separation of rare earth complexes with EDTA on the polyacrylate anion-exchangers applied mainly in the environment protection so far indicate that they can be applied in anionexchange separation of lanthanide complexes with aminopolycarboxylic acids. It was shown that the weakly basic polyacrylate gel anion-exchanger Amberlite IRA-68 is the most effective in purification of Y3+ from Nd3+ in comparison with the strongly basic anion-exchangers of this type.

  3. Transport: Introduction

    Science.gov (United States)

    Lewis, William; Rosenberg, Sanders D.

    1992-01-01

    Space transportation requirements for the NASA baseline scenario for future space missions are discussed. Spacecraft/propulsion technologies required for surface-to-orbit, orbit-to-orbit, and surface (lunar) transportation are addressed.

  4. Pulse radiolysis study of the formation and the reactivity of baicalin radical anion, and in comparison with rutin, quercetin and acyrlate ester radical anions in ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Sun Gang [Department of Applied Chemistry, College of Chemical and Molecular Engineering, Peking University, Beijing 100871 (China) and Department of Internal Medicine, Division of Bioorganic Chemistry and Molecular Pharmacology, Washington University School of Medicine, St Louis, MO 63110 (United States)]. E-mail: gangsun@wustl.edu; Wang Wenfeng [Shanghai Institute of Applied Physics, Academic Sinica, P.O. Box 800-204, Shanghai 201800 (China); Wu Jilan [Department of Applied Chemistry, College of Chemical and Molecular Engineering, Peking University, Beijing 100871 (China)]. E-mail: wangwqchem@pku.edu.cn

    2007-06-15

    The reaction of solvated electrons with baicalin in N{sub 2}-saturated ethanol has been studied by pulse radiolysis. The results show that a solvated electron can add to baicalin and generate a baicalin radical anion with a maximum UV absorbance peak at 360 nm. Its molar extinction coefficient at this wavelength is 1.3x10{sup 4} M{sup -1} cm{sup -1}. The rate constant for the build-up of the baicalin radical anion is 1.3({+-}0.4)x10{sup 10} M{sup -1} s{sup -1}. Decay of the radical anion is induced by a proton transfer reaction and a recombination reaction, which involves a pseudo-first-order reaction with rate constant 2.6({+-}0.4)x10{sup 3} s{sup -1} and a second-order reaction with rate constant 1.3({+-}0.2)x10{sup 9} M{sup -1} s{sup -1}. The effect of acetaldehyde on the decay of the baicalin radical anion was also investigated. Electron transfer between the baicalin radical anion and acetaldehyde was not observed, probably due to the low rate of electron transfer between the baicalin radical anion and acetaldehyde. Reactivity of the rutin, quercetin, baicalin and ethyl acrylate radical anions are also compared.

  5. Anions dramatically enhance proton transfer through aqueous interfaces.

    Science.gov (United States)

    Mishra, Himanshu; Enami, Shinichi; Nielsen, Robert J; Hoffmann, Michael R; Goddard, William A; Colussi, Agustín J

    2012-06-26

    Proton transfer (PT) through and across aqueous interfaces is a fundamental process in chemistry and biology. Notwithstanding its importance, it is not generally realized that interfacial PT is quite different from conventional PT in bulk water. Here we show that, in contrast with the behavior of strong nitric acid in aqueous solution, gas-phase HNO(3) does not dissociate upon collision with the surface of water unless a few ions (> 1 per 10(6) H(2)O) are present. By applying online electrospray ionization mass spectrometry to monitor in situ the surface of aqueous jets exposed to HNO(3(g)) beams we found that NO(3)(-) production increases dramatically on > 30-μM inert electrolyte solutions. We also performed quantum mechanical calculations confirming that the sizable barrier hindering HNO(3) dissociation on the surface of small water clusters is drastically lowered in the presence of anions. Anions electrostatically assist in drawing the proton away from NO(3)(-) lingering outside the cluster, whose incorporation is hampered by the energetic cost of opening a cavity therein. Present results provide both direct experimental evidence and mechanistic insights on the counterintuitive slowness of PT at water-hydrophobe boundaries and its remarkable sensitivity to electrostatic effects. PMID:22689964

  6. Dynamics of anion-molecule reactions at low energy

    International Nuclear Information System (INIS)

    Anion-molecule reactions must find their way through deeply bound entrance and exit channel complexes separated by a central barrier. This results in low reaction rates and rich dynamics since direct pathways compete with the formation of transient intermediates. In this thesis we examine the probability of proton transfer to a small anion and transient lifetimes of a thermoneutral bimolecular nucleophilic substitution (SN2) reaction at well defined variable temperature down to 8 Kelvin in a multipole trap. The observed strong inverse temperature dependence is attributed to the deficit of available quantum states in the entrance channel at decreasing temperature. Furthermore we investigate scattering dynamics of SN2 reactions at defined relative energy between 0.4 and 10 eV by crossed beam slice imaging. A weakly exothermic reaction with high central barrier proceeds via an indirect, complex-mediated mechanism at low relative energies featuring high internal product excitation in excellent quantitative agreement with a statistical model. In contrast, direct backward scattering prevails for higher energies with product velocities close to the kinematical cutoff. For a strongly exothermic reaction, competing SN2-, dihalide- and proton transfer-channels are explored which proceed by complex mediation for low energy and various rebound-, grazing- and collision induced bond rupture-mechanisms at higher energy. From our data and a collaboration with theory we identify a new indirect roundabout SN2 mechanism involving CH3-rotation. (orig.)

  7. Functional role of anion channels in cardiac diseases

    Institute of Scientific and Technical Information of China (English)

    Da-yue DUAN; Luis LH LIU; Nathan BOZEAT; Z Maggie HUANG; Sunny Y XIANG; Guan-lei WANG; Linda YE; Joseph R HUME

    2005-01-01

    In comparison to cation (K+, Na+, and Ca2+) channels, much less is currently known about the functional role of anion (Cl-) channels in cardiovascular physiology and pathophysiology. Over the past 15 years, various types of Cl- currents have been recorded in cardiac cells from different species including humans. All cardiac Cl- channels described to date may be encoded by five different Cl- channel genes: the PKA- and PKC-activated cystic fibrosis tansmembrane conductance regulator (CFTR), the volume-regulated ClC-2 and ClC-3, and the Ca2+-activated CLCA or Bestrophin. Recent studies using multiple approaches to examine the functional role of Cl- channels in the context of health and disease have demonstrated that Cl- channels might contribute to: 1) arrhythmogenesis in myocardial injury; 2) cardiac ischemic preconditioning; and 3) the adaptive remodeling of the heart during myocardial hypertrophy and heart failure. Therefore,anion channels represent very attractive novel targets for therapeutic approaches to the treatment of heart diseases. Recent evidence suggests that Cl- channels,like cation channels, might function as a multiprotein complex or functional module.In the post-genome era, the emergence of functional proteomics has necessitated a new paradigm shift to the structural and functional assessment of integrated Cl- channel multiprotein complexes in the heart, which could provide new insight into our understanding of the underlying mechanisms responsible for heart disease and protection.

  8. A Novel Methodology to Synthesize Highly Conductive Anion Exchange Membranes

    Science.gov (United States)

    He, Yubin; Pan, Jiefeng; Wu, Liang; Zhu, Yuan; Ge, Xiaolin; Ran, Jin; Yang, Zhengjin; Xu, Tongwen

    2015-08-01

    Alkaline polyelectrolyte fuel cell now receives growing attention as a promising candidate to serve as the next generation energy-generating device by enabling the use of non-precious metal catalysts (silver, cobalt, nickel et al.). However, the development and application of alkaline polyelectrolyte fuel cell is still blocked by the poor hydroxide conductivity of anion exchange membranes. In order to solve this problem, we demonstrate a methodology for the preparation of highly OH- conductive anion exchange polyelectrolytes with good alkaline tolerance and excellent dimensional stability. Polymer backbones were grafted with flexible aliphatic chains containing two or three quaternized ammonium groups. The highly flexible and hydrophilic multi-functionalized side chains prefer to aggregate together to facilitate the formation of well-defined hydrophilic-hydrophobic microphase separation, which is crucial for the superior OH- conductivity of 69 mS/cm at room temperature. Besides, the as-prepared AEMs also exhibit excellent alkaline tolerance as well as improved dimensional stability due to their carefully designed polymer architecture, which provide new directions to pursue high performance AEMs and are promising to serve as a candidate for fuel cell technology.

  9. Dynamics of anion-molecule reactions at low energy

    Energy Technology Data Exchange (ETDEWEB)

    Mikosch, J.

    2007-11-15

    Anion-molecule reactions must find their way through deeply bound entrance and exit channel complexes separated by a central barrier. This results in low reaction rates and rich dynamics since direct pathways compete with the formation of transient intermediates. In this thesis we examine the probability of proton transfer to a small anion and transient lifetimes of a thermoneutral bimolecular nucleophilic substitution (S{sub N}2) reaction at well defined variable temperature down to 8 Kelvin in a multipole trap. The observed strong inverse temperature dependence is attributed to the deficit of available quantum states in the entrance channel at decreasing temperature. Furthermore we investigate scattering dynamics of S{sub N}2 reactions at defined relative energy between 0.4 and 10 eV by crossed beam slice imaging. A weakly exothermic reaction with high central barrier proceeds via an indirect, complex-mediated mechanism at low relative energies featuring high internal product excitation in excellent quantitative agreement with a statistical model. In contrast, direct backward scattering prevails for higher energies with product velocities close to the kinematical cutoff. For a strongly exothermic reaction, competing S{sub N}2-, dihalide- and proton transfer-channels are explored which proceed by complex mediation for low energy and various rebound-, grazing- and collision induced bond rupture-mechanisms at higher energy. From our data and a collaboration with theory we identify a new indirect roundabout S{sub N}2 mechanism involving CH{sub 3}-rotation. (orig.)

  10. Liquid anion-exchange separation of vanadium from malonate media

    International Nuclear Information System (INIS)

    Vanadium (IV) and (V) can be quantitatively extracted with 0.2 mol/l Amberlite LA-2 in xylene at pH 3.0 from 0.02 mol/l malonic acid, stripped with 0.5 mol/l hydrochloric acid, and determined spectrophotometrically. Five other liquid anion exchangers (Amberlite LA-1, Primene JM-T, Aliquat 336S, TOA and TIOA) were examined as possible extractants. The extraction of vanadium(IV) was found to be quantitative only with Amberlite LA-2, while that of vanadium(V) was quantitative with Amberlite LA-1 and LA-2, Primene JM-T and Aliquat 336S. Eight common solvents were tested as diluents; of these hexane, cyclohexane, benzene, and xylene were found to be satisfactory. Vanadium was separated from elements that do not form anionic complexes with malonic acid by selective extraction, from those that form weak complexes by washing the organic extract with water, and from metals that form strong malonato complexes by selective stripping with hydrochloric, nitric, or sulphuric acid. The method has been applied to the determination of vanadium in steel, coal fly ash and fuel oil. The precision of measurement is within ±5% and the detection limit of the method for vanadium is 0.5 mg/kg. (orig.)

  11. A consistent model for anion exclusion and surface diffusion

    International Nuclear Information System (INIS)

    A decomposition of the diffusion flux equation for an electrostatically bound and mobile hydrated ion into two components is proposed. The first component includes the effects arising solely from the irregular pore shape and increase in solvent viscosity in the proximity of negatively charged pore walls. Apart from these effects, the second flux component includes an additional contribution from an increased (decreased) concentration for cations (anions) close to the pore walls. Defining the distribution coefficient, Kd, in a fashion that allows negative values for co-ions readily accounts for their exclusion without the need to introduce somewhat artificial quantities like the effective co-ion porosity. In this study, it is thus possible to retain the purely volumetric meaning of the porosity and to maintain consistency throughout the conceptualization for anions, cations and electrically neutral species. Furthermore, the decomposition of the flux equation provides support for surface diffusion, a subject of great controversy and lively debate in the literature. In this connection, the role of concentration to regulate the diffusive flux for ions in relation to neutral species is emphasized. Implications for the theoretical apparent and effective diffusivities in compacted montmorillonite clay are also discussed and a modified form of the macroscopic theory is proposed

  12. Diffusion of anions and cations in compacted sodium bentonite

    International Nuclear Information System (INIS)

    The thesis presents the results of studies on the diffusion mechanisms of anions and cations in compacted sodium bentonite, which is planned to be used as a buffer material in nuclear waste disposal in Finland. The diffusivities and sorption factors were determined by tracer experiments. The pore volume accessible to chloride, here defined as effective porosity, was determined as a function of bentonite density and electrolyte concentration in water, and the Stern-Gouy double-layer model was used to explain the observed anion exclusion. The sorption of Cs+ and Sr2+ was studied in loose and compacted bentonite samples as a function of the electrolyte concentration in solution. In order to obtain evidence of the diffusion of exchangeable cations, defined as surface diffusion, the diffusivities of Cs+ and Sr2+ in compacted bentonite were studied as a function of the sorption factor, which was varied by electrolyte concentration in solution. The measurements were performed both by a non-steady state method and by a through-diffusion method. (89 refs., 35 fig., 4 tab.)

  13. Fibrin solubilizing properties of certain anionic and cationic detergents.

    Science.gov (United States)

    Chakrabarty, S

    1989-08-15

    The fibrinolytic (fibrin dissolving) properties of several anionic, cationic, nonionic and zwitterionic detergents were assessed in an in vitro fibrin agarose assay. Of the 4 anionic detergents tested, only sodium dodecyl sulfate (SDS) was found to be fibrinolytic. SDS was fibrinolytic either in the absence or presence of factor XIII. Four other cationic detergents were found to possess similar fibrinolytic properties. These cationic detergents were cetyltrimethylammonium bromide (CTAB), mix alkyltrimethyl ammonium bromide (MTAB), hexadecyltrimethylammonium bromide (HTAB) and cetylpyridium chloride (CPC). The nonionic (digitonin, triton X-100/tween 20) and zeitterionic (CHAPS, zeittergent 3-08) detergents were not fibrinolytic. Detergents mediated fibrinolysis, unlike that of tissue type plasminogen activator and urokinase, was independent of the presence of plasminogen. Non-detergents such as polyethylene glycol and highly charged compounds such as poly-1-lysine and poly-1-glutamic acid were not fibrinolytic. Fibrinolytic activity was observed for SDS and the cationic detergents at concentrations ranging from 0.1-10 percent. The effects of these fibrinolytic detergents (SDS, CTAB, MTAB, HTAB and CPC) on clot formation and on pre-formed clots were then assessed, using freshly drawn human venous blood. Incorporation of these detergents into blood inhibited the formation of clots in a concentration dependent manner. The detergents were also able to dissolve pre-formed clots in a similar fashion. SDS was found to be most potent in these properties. PMID:2510356

  14. Anion-exchangeable inorganic-organic hybrid materials synthesized without using templates

    Institute of Scientific and Technical Information of China (English)

    XU Xianzhu; SONG Jiangwei; LI Defeng; XIAO Fengshou

    2004-01-01

    Inorganic-organic hybrid materials have been obtained at room temperature in aqueous solution without using the templates of surfactants. The materials are care fully characterized by anion-exchange measurement, elements analysis, X-ray diffraction, and infrared spectroscopy. Notably, the anion-exchange capacity of the samples (3.9 Interestingly, both small and large anions could be easily exchanged into the samples due to the plasticity of the sam pies, along with the phase transition.

  15. Preparation, Characterization and Adsorption Performance of a Novel Anionic Starch Microsphere

    OpenAIRE

    Yati Yang; Xiuzhi Wei; Peng Sun; Juanmin Wan

    2010-01-01

    Neutral starch microspheres (NSMs) were synthesized by an inverse microemulsion technology with epichlorohydrin as a crosslinker and soluble starch as starting material. Anionic starch microspheres (ASMs) were prepared from NSMs by the secondary polymerization with chloroacetic acid as the anionic etherifying agent. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and laser diffraction particle size analyzer were used to characterize the anionic starch micro...

  16. Entwicklung anion-chiraler ionischer Flüssigkeiten und ihre Anwendung in der Katalyse

    OpenAIRE

    Gausepohl, Rolf

    2006-01-01

    The aim of this dissertation was the investigation of anion-chiral ionic liquids (ILs) in catalytic reactions in order to investigate a potential chirality transfer. Thus chirality has been incorporated into the anion of the molten salt. There are several examples of catalytic reactions known in literature to be heavily influenced by the choice of the anions covering a large scope of influence from conversion to even enantioselectivity. It was aimed to combine this effect with the structural ...

  17. On the Formation of (Anionic) Excited Helium Dimers in Helium Droplets

    OpenAIRE

    Huber, Stefan E.; Mauracher, Andreas

    2014-01-01

    Metastable atomic and molecular helium anions exhibiting high-spin quartet configurations can be produced in helium droplets via electron impact. Their lifetimes allow detection in mass spectrometric experiments. Formation of atomic helium anions comprises collision-induced excitation of ground state helium and concomitant electron capture. Yet the formation of molecular helium anions in helium droplets has been an unresolved issue. In this work, we explore the interaction of excited helium a...

  18. Modeling the interaction of nitrate anions with ozone and atmospheric moisture

    Institute of Scientific and Technical Information of China (English)

    A. Y. Galashev

    2015-01-01

    The molecular dynamics method is used to investigate the interaction between one–six nitrate anions and water clus-ters absorbing six ozone molecules. The infrared (IR) absorption and reflection spectra are reshaped significantly, and new peaks appear at Raman spectra due to the addition of ozone and nitrate anions to the disperse water system. After ozone and nitrate anions are captured, the average (in frequency) IR reflection coefficient of the water disperse system increased drastically and the absorption coefficient fell.

  19. Removal of chromium complex dye from aqueous solutions using strongly basic and weakly basic anion exchangers

    OpenAIRE

    Kauspediene, D.; Kazlauskiene E.; Selskiene, A.

    2010-01-01

    Removal of chromium complex dye from aqueous solutions by sorption onto a weakly basic, acrylic matrix anion exchanger Purolite A845 and a strongly basic, polystyrene matrix anion exchanger Purolite A 500P has been investigated under various experimental conditions: the initial dye concentration, pH and temperature. The sorption of chromium complex dye proceeds as a result of miscellaneous interactions between the dye and anion exchanger: ion exchange and physical sorption. The removal effici...

  20. Neurotransmitter transporters

    DEFF Research Database (Denmark)

    Gether, Ulrik; Andersen, Peter H; Larsson, Orla M;

    2006-01-01

    The concentration of neurotransmitters in the extracellular space is tightly controlled by distinct classes of membrane transport proteins. This review focuses on the molecular function of two major classes of neurotransmitter transporter that are present in the cell membrane of neurons and....... Recent research has provided substantial insight into the structure and function of these transporters. In particular, the recent crystallizations of bacterial homologs are of the utmost importance, enabling the first reliable structural models of the mammalian neurotransmitter transporters to be...

  1. The remarkable ability of anions to bind dihydrogen.

    Science.gov (United States)

    Della, Therese Davis; Suresh, Cherumuttathu H

    2016-05-25

    The structural features and hydrogen binding affinity of anions F(-), Cl(-), Br(-), OH(-), NH2(-), NO2(-), CN(-), and ClO(-) have been explored at the CCSD(T)/aug-cc-pVTZ//CCSD/6-311++G(d,p) level of coupled cluster theory and the M06L/6-311++G(d,p) level of density functional theory along with a two-point extrapolation to the complete basis set limit and a benchmark study at CCSD(T) and MP2 levels. The coupled cluster, MP2 and DFT methods yield comparable results and show that anions have very high capacity to store hydrogen as the weight percent of H2 in the highest H2-coordinated state of F(-), Cl(-), Br(-), OH(-), NH2(-), NO2(-), CN(-), and ClO(-) is 56.0, 47.6, 33.5, 64.0, 65.4, 41.2, 55.4, and 40.0 wt%, respectively. The CCSD(T)/aug-cc-pVTZ//CCSD/6-311++G(d,p) results are presented for anions coordinated with up to nine or ten H2 molecules, while up to the entire first coordination shell is computed using the M06L method which revealed H2 coordination numbers of 12, 16, 20, 15, 15, 16, 16, and 17, respectively, for F(-), Cl(-), Br(-), OH(-), NH2(-), NO2(-), CN(-), and ClO(-). An increase in the total interaction energy (Eint) and a decrease in the interaction energy per H2 molecule (Eint/H2) with an increase in the number of coordinated H2 molecules are observed. However, the decrease in Eint/H2 is very less and even in the highest coordinated anions, substantially good values of Eint/H2 are observed, viz. 4.24, 2.59, 2.09, 3.32, 3.07, 2.36, 2.31, and 2.63 kcal mol(-1) for F(-), Cl(-), Br(-), OH(-), NH2(-), NO2(-), CN(-), and ClO(-), respectively, which are comparable with the values obtained for complexes with lesser H2 coordination. The stability of the complexes is attributed to the formation of a large number of non-covalent X(-)H bonds as revealed by the identification of bond critical points in the quantum theory of atoms in molecules (QTAIM) analysis. Further, critical features of molecular electrostatic potential (MESP) have been used to correlate the

  2. Primary and secondary thyroid hormone transporters

    Directory of Open Access Journals (Sweden)

    Kinne Anita

    2011-08-01

    Full Text Available Abstract Thyroid hormones (TH are essential for the development of the human brain, growth and cellular metabolism. Investigation of TH transporters became one of the emerging fields in thyroid research after the discovery of inactivating mutations in the Monocarboxylate transporter 8 (MCT8, which was found to be highly specific for TH transport. However, additional transmembrane transporters are also very important for TH uptake and efflux in different cell types. They transport TH as secondary substrates and include the aromatic amino acid transporting MCT10, the organic anion transporting polypeptides (e.g. OATP1C1, OATP1A2, OPTP1A4 and the large neutral amino acid transporters (LAT1 and LAT2. These TH transporters characteristically possess 12 transmembrane spanners but due to the strong differing sequences between the three transporter families we assume an identical conformation is not very likely. In contrast to the others, the LAT family members form a heterodimer with the escort protein 4F2hc/CD98. A comparison of sequence proportions, locations and types of functional sensitive features for TH transport discovered by mutations, revealed that transport sensitive charged residues occur as conserved amino acids only within each family of the transporter types but not in all putative TH transporters. Based on the lack of highly conserved sensitive charged residues throughout the three transporter families as a common counterpart for the amino acid moiety of the substrates, we conclude that the molecular transport mechanism is likely organized either a by different molecular determinants in the divergent transporter types or b the counterparts for the substrates` amino acid moiety at the transporter are not any charged side chains but other proton acceptors or donators. However, positions of transport sensitive residues coincide at transmembrane helix 8 in the TH transporter MCT8, OATP1C1 and another amino acid transporter, the L

  3. A photoelectron spectroscopic and computational study of the o-dicarbadodecaborane parent anion

    Science.gov (United States)

    Zhang, Xinxing; Bowen, Kit

    2016-06-01

    We report a combined photoelectron spectroscopic and computational study of the o-dicarbadodecaborane (o-carborane) parent anion, (C2B10H12)-. Previous studies that focused on the electrophilic nature of o-carborane led to tantalizing yet mixed results. In our study, we confirmed that o-carborane does in fact form a parent anion and that it has considerable stability. This anion is an isomer ("Anion iso 2") where unlike in neutral o-carborane, the two carbon atoms are not bound.

  4. Halides with Fifteen Aliphatic C–H···Anion Interaction Sites

    Science.gov (United States)

    Shi, Genggongwo; Aliakbar Tehrani, Zahra; Kim, Dongwook; Cho, Woo Jong; Youn, Il-Seung; Lee, Han Myoung; Yousuf, Muhammad; Ahmed, Nisar; Shirinfar, Bahareh; Teator, Aaron J.; Lastovickova, Dominika N.; Rasheed, Lubna; Lah, Myoung Soo; Bielawski, Christopher W.; Kim, Kwang S.

    2016-07-01

    Since the aliphatic C–H···anion interaction is relatively weak, anion binding using hydrophobic aliphatic C–H (Cali–H) groups has generally been considered not possible without the presence of additional binding sites that contain stronger interactions to the anion. Herein, we report X-ray structures of organic crystals that feature a chloride anion bound exclusively by hydrophobic Cali–H groups. An X-ray structure of imidazolium-based scaffolds using Cali–H···A‑ interactions (A‑ = anion) shows that a halide anion is directly interacting with fifteen Cali–H groups (involving eleven hydrogen bonds, two bidentate hydrogen-bond-type binding interactions and two weakly hydrogen-bonding-like binding interactions). Additional supporting interactions and/or other binding sites are not observed. We note that such types of complexes may not be rare since such high numbers of binding sites for an anion are also found in analogous tetraalkylammonium complexes. The Cali–H···A‑ interactions are driven by the formation of a near-spherical dipole layer shell structure around the anion. The alternating layers of electrostatic charge around the anion arise because the repulsions between weakly positively charged H atoms are reduced by the presence of the weakly negatively charged C atoms connected to H atoms.

  5. Halides with Fifteen Aliphatic C-H···Anion Interaction Sites.

    Science.gov (United States)

    Shi, Genggongwo; Aliakbar Tehrani, Zahra; Kim, Dongwook; Cho, Woo Jong; Youn, Il-Seung; Lee, Han Myoung; Yousuf, Muhammad; Ahmed, Nisar; Shirinfar, Bahareh; Teator, Aaron J; Lastovickova, Dominika N; Rasheed, Lubna; Lah, Myoung Soo; Bielawski, Christopher W; Kim, Kwang S

    2016-01-01

    Since the aliphatic C-H···anion interaction is relatively weak, anion binding using hydrophobic aliphatic C-H (Cali-H) groups has generally been considered not possible without the presence of additional binding sites that contain stronger interactions to the anion. Herein, we report X-ray structures of organic crystals that feature a chloride anion bound exclusively by hydrophobic Cali-H groups. An X-ray structure of imidazolium-based scaffolds using Cali-H···A(-) interactions (A(-) = anion) shows that a halide anion is directly interacting with fifteen Cali-H groups (involving eleven hydrogen bonds, two bidentate hydrogen-bond-type binding interactions and two weakly hydrogen-bonding-like binding interactions). Additional supporting interactions and/or other binding sites are not observed. We note that such types of complexes may not be rare since such high numbers of binding sites for an anion are also found in analogous tetraalkylammonium complexes. The Cali-H···A(-) interactions are driven by the formation of a near-spherical dipole layer shell structure around the anion. The alternating layers of electrostatic charge around the anion arise because the repulsions between weakly positively charged H atoms are reduced by the presence of the weakly negatively charged C atoms connected to H atoms. PMID:27444513

  6. Reillex/trademark/ HPQ: A new, macroporous polyvinylpyridine resin for separating plutonium using nitrate anion exchange

    International Nuclear Information System (INIS)

    Anion exchange in nitric acid is the major aqueous process used to recover and purify plutonium from impure scrap materials. Most strong-base anion exchange resins incorporate a styrene-divinylbenzene copolymer. A newly available, macroporous anion exchange resin based on a copolymer of 1-methyl-4-vinylpyridine and divinylbenzene has been evaluated. Comparative data for Pu(IV) sorption kinetics and capacity are presented for this new resin and two other commonly used anion exchange resins. The new resin offers high capacity and rapid sorption kinetics for Pu(IV) from nitric acid, as well as greater stability to chemical and radiolytic degradation. 8 refs., 12 figs

  7. A colorimetric and fluorescence enhancement anion probe based on coumarin compounds.

    Science.gov (United States)

    Zhao, Limin; Liu, Ge; Zhang, Baofeng

    2016-12-01

    In this paper, anion probe 1 was designed and synthesized by using phenprocoumon containing acyl hydrazine with p-nitro azo salicylaldehyde reaction Dickson et al. (2008) Dickson et al. (2008) [1]. In the anion probe 1, the nitro moiety is a signaling group and the phenolic hydroxyl moiety is anion binding site. Then the anion probe 1 was characterized by mass spectra (MS) and infrared spectra (IR). The binding properties of the anion probe 1 for anions such as F(-), AcO(-), H2PO4(-), OH(-), Cl(-), Br(-) and I(-) were investigated by ultraviolet-visible (UV-Vis) spectra and fluorescence spectra Shao et al. (2008) Shao et al. (2008) [2]. Furthermore, the color of anion probe 1 after addition of F(-), AcO(-), H2PO4(-) and OH(-) in DMSO changed from yellow to blue, while no obvious color changes were observed by addition of other tested anions. Accordingly, the anion probe 1 could sense visually F(-), AcO(-), H2PO4(-) and OH(-) without resorting to any spectroscopic instrumentation Amendola et al. (2010) Amendola et al. (2010) [3]. PMID:27323317

  8. A photoelectron spectroscopic and computational study of the o-dicarbadodecaborane parent anion.

    Science.gov (United States)

    Zhang, Xinxing; Bowen, Kit

    2016-06-14

    We report a combined photoelectron spectroscopic and computational study of the o-dicarbadodecaborane (o-carborane) parent anion, (C2B10H12)(-). Previous studies that focused on the electrophilic nature of o-carborane led to tantalizing yet mixed results. In our study, we confirmed that o-carborane does in fact form a parent anion and that it has considerable stability. This anion is an isomer ("Anion iso 2") where unlike in neutral o-carborane, the two carbon atoms are not bound. PMID:27306011

  9. Anion retention in soil: Possible application to reduce migration of buried technetium and iodine

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, R.K.; Duckart, E.C. (California Univ., Berkeley, CA (United States). Dept. of Soil Science); O' Donnell, E. (Nuclear Regulatory Commission, Washington, DC (United States))

    1992-12-01

    Before testing the performance characteristics of andisols for retention of anions in the near-field environment of Low Level Wastes (LLW) disposal facilities it is necessary to locate one or more sufficiently extensive bodies of natural soil with the highest possible natural anion exchange capacity. For this purpose we developed a rugged, portable semiquantitative field test for anion exchange capacity based on short-term sorption of iodide by soil samples. We validated the iodide sorption field test against a well established quantitative laboratory test based on anion exchange of chloride and nitrate, then carried out an initial survey of volcanic terrain in northern California using the field test.

  10. The Influence of Active Transport Systems on Morphine -6-Glucuronide Transport in MDCKII and MDCK-PGP Cells

    Directory of Open Access Journals (Sweden)

    SO. Mashayekhi

    2011-12-01

    Full Text Available Background and the purpose of the study: Morphine-6-glucuronide (M6G is a potent metabolite of morphine which has high penetration into the brain despite its high polarity, which could be the result of an active transport system involved in M6G transport through blood brain barrier. Examples of such transporters are p-glycoprotein (PGP, probenecid-sensitive transport mechanism, multidrug resistance related protein 1-3, the organic anion transporter family, and the organic anion transporter polypeptide family. The aim of present study was to elucidate the mechanisms involved in transporting morphine's potent metabolite, M6G.Methods: M6G permeability via two cell lines; MDCKII and MDCK-PGP, was compared with that of sucrose. M6G transport was examined in different concentrations and in the presence of inhibitors of different transport systems such as cyclosporine, digoxin and probenecid. M6G concentration was measured using ELISA assay. The method was sensitive, reliable and reproducible.Results: The results confirmed that M6G could cross a layer of MDCK II or MDR-PGP cells more than sucrose could. It was also observed that M6G is a PGP transporter substrate. Its permeability was increased by the use of a PGP expressed cell line, and also in the presence of a strong PGP inhibitor. Digoxin related transporters such as Oatp2 may also involved in transport of M6G. M6G seemed to be a glucose transporter 1 substrate, but was not a substrate to probenecid sensitive transporters.Major conclusion: It is concluded that different transporters are responsible for M6G transports via different membrane, which could have effects on its pharmacokinetics or pharmacodynamics.

  11. Human vascular smooth muscle cells express a urate transporter.

    Science.gov (United States)

    Price, Karen L; Sautin, Yuri Y; Long, David A; Zhang, Li; Miyazaki, Hiroki; Mu, Wei; Endou, Hitoshi; Johnson, Richard J

    2006-07-01

    An elevated serum uric acid is associated with the development of hypertension and renal disease. Renal regulation of urate excretion is largely controlled by URAT1 (SLC22A12), a member of the organic anion transporter superfamily. This study reports the specific expression of URAT1 on human aortic vascular smooth muscle cells, as assessed by reverse transcription-PCR and Western blot analysis. Expression of URAT1 was localized to the cell membrane. Evidence that the URAT1 transporter was functional was provided by the finding that uptake of 14C-urate was significantly inhibited in the presence of probenecid, an organic anion transporter inhibitor. It is proposed that URAT1 may provide a mechanism by which uric acid enters the human vascular smooth muscle cell, a finding that may be relevant to the role of uric acid in cardiovascular disease. PMID:16775029

  12. Evaluation of Proposed In Vivo Probe Substrates and Inhibitors for Phenotyping Transporter Activity in Humans.

    Science.gov (United States)

    Momper, Jeremiah D; Tsunoda, Shirley M; Ma, Joseph D

    2016-07-01

    Drug transporters are present in various tissues and have a significant role in drug absorption, distribution, and elimination. The International Transporter Consortium has identified 7 transporters of increasing importance from evidence of clinically significant transporter-mediated drug-drug interactions. The transporters are P-glycoprotein, breast cancer resistance protein, organic anion transporting polypeptide (OATP) 1B1, OATP1B3, organic cation transporter 2, organic anion transporters (OAT) 1, and OAT3. Decision trees were created based on in vitro experiments to determine whether an in vivo transporter-mediated drug-drug interaction study is needed. Phenotyping is a methodology that evaluates real-time in vivo transporter activity, whereby changes in a probe substrate or probe inhibitor reflect alternations in the activity of the specified transporter. In vivo probe substrates and/or probe inhibitors have been proposed for each aforementioned transporter. In vitro findings and animal models provide the strongest evidence regarding probe specificity. However, such findings have not conclusively correlated with human phenotyping studies. Furthermore, the extent of contribution from multiple transporters in probe disposition complicates the ability to discern if study findings are the result of a specific transporter and thus provide a recommendation for a preferred probe for a drug transporter. PMID:27385182

  13. Formation reaction mechanisms of hydroxide anions from Mg(OH){sub 2} layers

    Energy Technology Data Exchange (ETDEWEB)

    Vaiss, Viviane S. [Departamento de Química, Universidade Federal de Juiz de Fora, Juiz de Fora, MG, 36036-330 (Brazil); Borges, Itamar [Departamento de Química, Instituto Militar de Engenharia, Rio de Janeiro, RJ, 22290-270 (Brazil); Wypych, Fernando [Departamento de Química, Universidade Federal do Paraná, Curitiba, PR, 81531-990 (Brazil); Leitão, Alexandre A., E-mail: alexandre.leitao@ufjf.edu.br [Departamento de Química, Universidade Federal de Juiz de Fora, Juiz de Fora, MG, 36036-330 (Brazil)

    2013-06-03

    Highlights: • Mg(OH){sub 2} hydroxide anion migrates to the surface thus producing an adsorbed free hydroxide anion. • Orbital contributions from adsorbed free hydroxide anion dominate the shape of total DOS in the region near the Fermi level. • The hydroxide anion formation reaction in Mg(OH){sub 2} from Mg(OH){sub 2} dissociation is slower than the formation from H{sub 2}O dissociation. • Formation of hydroxide anions in a layered hydroxide would involve reaction of H{sub 2}O molecules with layer hydroxide anions. - Abstract: DFT calculations with periodic boundary conditions were used to study two formation reaction mechanisms of adsorbed free hydroxide anions on the surface of the brucite, Mg(OH){sub 2}. In the first mechanism, we investigated the migration of a hydroxide anion present in the structure of Mg(OH){sub 2} to the layer surface. In the second, a mechanism composed of three elementary reactions was examined for the reaction of H{sub 2}O molecules with the brucite layer surface. The result in both mechanisms is the formation of hydroxide anions and a hydroxide vacancy in the positively charged Mg(OH){sub 2} layer. The global reaction is the same in both cases and the computed Gibbs free energy variation equals 37.5 kcal/mol at room temperature. The reaction barrier for the formation of hydroxide anion on Mg(OH){sub 2} surface from H{sub 2}O dissociation (27.6 kcal/mol) is lower than the reaction barrier for the formation of hydroxide anions from Mg(OH){sub 2} dissociation (43.2 kcal/mol)

  14. Formation reaction mechanisms of hydroxide anions from Mg(OH)2 layers

    International Nuclear Information System (INIS)

    Highlights: • Mg(OH)2 hydroxide anion migrates to the surface thus producing an adsorbed free hydroxide anion. • Orbital contributions from adsorbed free hydroxide anion dominate the shape of total DOS in the region near the Fermi level. • The hydroxide anion formation reaction in Mg(OH)2 from Mg(OH)2 dissociation is slower than the formation from H2O dissociation. • Formation of hydroxide anions in a layered hydroxide would involve reaction of H2O molecules with layer hydroxide anions. - Abstract: DFT calculations with periodic boundary conditions were used to study two formation reaction mechanisms of adsorbed free hydroxide anions on the surface of the brucite, Mg(OH)2. In the first mechanism, we investigated the migration of a hydroxide anion present in the structure of Mg(OH)2 to the layer surface. In the second, a mechanism composed of three elementary reactions was examined for the reaction of H2O molecules with the brucite layer surface. The result in both mechanisms is the formation of hydroxide anions and a hydroxide vacancy in the positively charged Mg(OH)2 layer. The global reaction is the same in both cases and the computed Gibbs free energy variation equals 37.5 kcal/mol at room temperature. The reaction barrier for the formation of hydroxide anion on Mg(OH)2 surface from H2O dissociation (27.6 kcal/mol) is lower than the reaction barrier for the formation of hydroxide anions from Mg(OH)2 dissociation (43.2 kcal/mol)

  15. Synergistic Malaria Parasite Killing by Two Types of Plasmodial Surface Anion Channel Inhibitors.

    Directory of Open Access Journals (Sweden)

    Margaret Pain

    Full Text Available Malaria parasites increase their host erythrocyte's permeability to a broad range of ions and organic solutes. The plasmodial surface anion channel (PSAC mediates this uptake and is an established drug target. Development of therapies targeting this channel is limited by several problems including interactions between known inhibitors and permeating solutes that lead to incomplete channel block. Here, we designed and executed a high-throughput screen to identify a novel class of PSAC inhibitors that overcome this solute-inhibitor interaction. These new inhibitors differ from existing blockers and have distinct effects on channel-mediated transport, supporting a model of two separate routes for solute permeation though PSAC. Combinations of inhibitors specific for the two routes had strong synergistic action against in vitro parasite propagation, whereas combinations acting on a single route produced only additive effects. The magnitude of synergism depended on external nutrient concentrations, consistent with an essential role of the channel in parasite nutrient acquisition. The identified inhibitors will enable a better understanding of the channel's structure-function and may be starting points for novel combination therapies that produce synergistic parasite killing.

  16. Flow Chronopotentiometry with Ion-Selective Membranes for Cation, Anion, and Polyion Detection.

    Science.gov (United States)

    Ghahraman Afshar, Majid; Crespo, Gastón A; Bakker, Eric

    2016-04-01

    We report here on the development of a chronopotentiometric readout for ion-selective electrodes that allows one to record transition times in continuous flow conditions without the necessity to stop the flow. A sample plug of 150 μL is injected into the carrier solution (0.5 mM NaCl) and subsequently transported to the detection cell (∼20 μL) at moderate flow rates (∼0.5 mL min(-1)), where a short current pulse (5s) is applied between the ionophore-based working electrode and a biocompatible and nonpolarizable Donnan exclusion anion-exchanger membrane reference/counter electrode. Flow conditions bear an influence on the thickness of the aqueous diffusion layer and result in a shift of the chronopotentiometric transition time with respect to stopped flow. Two models based on rotating disk electrodes and flow chronopotentiometry at metal-based electrodes were used to corroborate the data. The method was successfully applied to the determination of calcium, chloride, alkalinity, acidity, and protamine with a range of ion-selective membranes. Because of the limiting exposure time of ca. 20 s of the membranes with the sample, this approach is demonstrated to be useful for the detection of protamine in the therapeutic range of undiluted human blood. PMID:26932542

  17. Room-temperature silver-containing liquid metal salts with nitrate anions.

    Science.gov (United States)

    Schaltin, Stijn; Brooks, Neil R; Sniekers, Jeroen; Depuydt, Daphne; Van Meervelt, Luc; Binnemans, Koen; Fransaer, Jan

    2013-11-21

    The synthesis, structural, thermal and electrochemical properties of fluorine-free silver-containing ionic liquids are presented. The ionic liquid cations are formed by a silver(i) ion surrounded by two 1-alkylimidazole ligands, with the counter anions being nitrate ions. Depending on the alkyl chain length, the complexes were found to be liquids at room temperature or melting slightly above this. For the solid compounds it was possible to elucidate the structure by single crystal X-ray analysis. The ionic liquids are electroactive, have good mass transport properties and can be used for the electrodeposition of silver at high current densities. The thermal properties and stability of these compounds were tested by differential scanning calorimetry and thermogravimetric analysis. The viscosity of the ionic liquids follows a Vogel-Tamman-Fulcher relationship as a function of temperature. The electrochemical properties of the complexes were tested by cyclic voltammetry and the resulting electrodeposits were examined using scanning electron microscopy and atomic force microscopy. PMID:24097139

  18. Removal of both cationic and anionic contaminants by amphoteric starch.

    Science.gov (United States)

    Peng, Huanlong; Zhong, Songxiong; Lin, Qintie; Yao, Xiaosheng; Liang, Zhuoying; Yang, Muqun; Yin, Guangcai; Liu, Qianjun; He, Hongfei

    2016-03-15

    A novel amphoteric starch incorporating quaternary ammonium and phosphate groups was applied to investigate the efficiency and mechanism of cationic and anionic contaminant treatment. Its flocculation abilities for kaolin suspension and copper-containing wastewater were evaluated by turbidity reduction and copper removal efficiency, respectively. And the kinetics of formation, breakage and subsequent re-formation of aggregates were monitored using a Photometric Dispersion Analyzer (PDA) and characterized by flocculation index (FI). The results showed that amphoteric starch possessed the advantages of being lower-dosages-consuming and being stronger in shear resistance than cationic starch, and exhibited a good flocculation efficiency over a wide pH range from 3.0 to 11.0. PMID:26794754

  19. The sorption capacity of boron on anionic-exchange resin

    International Nuclear Information System (INIS)

    Boron sorption capacities on anionic-exchange resins vary with temperature, concentration, and resin cross-linkage. A semiempirical correlation, developed from boron solution chemistry, is presented to account for these variations. The relationship, based on boron chemistry and changes in Gibb's energy, can be stated approximately as Q = a1CBa2Za3 exp[-(a4T + a5T2 + a6Z0.5)]. Correlation parameters, which vary with resin type, are evaluated experimentally. Parameter values for macroporous resin Diaion PA 300 and for gel-type resins Diaion SA10 and Amberlite IRN 78LC are presented. The resulting expression is used to determine boron sorption and desorption limitations on ion exchangers at various temperatures and concentrations, and to determine the interfacial boron concentration in equilibrium and rate models

  20. The anion exchange behavior of Te and Sb

    International Nuclear Information System (INIS)

    The absorption behavior of Te and Sb in different oxidation states by anion exchange resins in hydrochloric acid medium has been studied. Distribution coefficients for Te(IV), Te(VI) as a function of HCl acid concentration (up to 3M HCl) have been determined. The absorbability for Sb(III) was noticed to be very high and could not be eluted out of the column using HCl as eluent. Sb(V) could be eluted quantitatively using 3M HCl. The present study clearly indicate that due to the EC/β+ decay of the parent isotopes 117,118Te, the daughter nuclei 117,118Sb are produced predominantly as Sb(III). (author)

  1. Vertical ionization energies of halogen anions in solution

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Based on the constrained equilibrium state theory,the nonequilibrium solvation energy is derived in the framework of the continuum model.The formula for spectral shift and vertical ionization energy are deduced for a single sphere cavity with the point charge assumption.The new model is adopted to investigate the vertical ionization for halogen atomic and molecular anions X(X = Cl,Br,I,Cl2,Br2,I2) in aqueous solution.According to the calculation using the CCSD-t/aug-cc-pVQZ method in vacuum,our final estimated vertical ionization energies in solution are very close to the experimental observations,while the traditional nonequilibrium solvation theory overestimates these vertical ionization energies.

  2. Uranium isotope separation by continuous anion exchange chromatography

    International Nuclear Information System (INIS)

    This paper reports a process for producing nuclear quality Uranium 235 (U235) from a substantially impure feed stock containing a mixture of uranium isotopes, including U235, forming a stationary phase from an anion exchange resin in the annulus of a rotating annular chromatograph; feeding the feed stock to the stationary phase to load less than 10% of the stationary phase; injecting a mobile phase comprising an eluant selected from the group consisting of aqueous solutions of sulfates, chlorides, nitrates and carbonates into the stationary phase; continuously rotating the annular chromatograph; collecting the U235 isotope in substantially pure, enriched form from the stationary phase; precipitating the U235 isotope as ammonium diurante with ammonium hydroxide; and calcining the ammonium diuranate to produce uranium oxide rich in U235 suitable for nuclear applications requiring substantially pure U235

  3. Anion formation in sputter ion sources by neutral resonant ionization

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, J. S., E-mail: johnsvogel@yahoo.com [University of California, 8300 Feliz Creek Dr., Ukiah, California 95482 (United States)

    2016-02-15

    Focused Cs{sup +} beams in sputter ion sources create mm-diameter pits supporting small plasmas that control anionization efficiencies. Sputtering produces overwhelmingly neutral products that the plasma can ionize as in a charge-change vapor. Electron capture between neutral atoms rises as the inverse square of the difference between the ionization potential of the Cs state and the electron affinity of the sputtered atom, allowing resonant ionization at very low energies. A plasma collision-radiation model followed electronic excitation up to Cs(7d). High modeled Cs(7d) in a 0.5 mm recess explains the 80 μA/mm{sup 2} C{sup −} current density compared to the 20 μA/mm{sup 2} from a 1 mm recess.

  4. UNCERTAINTIES OF ANION AND TOC MEASUREMENTS AT THE DWPF LABORATORY

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, T.

    2011-04-07

    The Savannah River Remediation (SRR) Defense Waste Processing Facility (DWPF) has identified a technical issue related to the amount of antifoam added to the Chemical Process Cell (CPC). Specifically, due to the long duration of the concentration and reflux cycles for the Sludge Receipt and Adjustment Tank (SRAT), additional antifoam has been required. The additional antifoam has been found to impact the melter flammability analysis as an additional source of carbon and hydrogen. To better understand and control the carbon and hydrogen contributors to the melter flammability analysis, SRR's Waste Solidification Engineering (WSE) has requested, via a Technical Task Request (TTR), that the Savannah River National Laboratory (SRNL) conduct an error evaluation of the measurements of key Slurry Mix Evaporator (SME) anions. SRNL issued a Task Technical and Quality Assurance Plan (TTQAP) [2] in response to that request, and the work reported here was conducted under the auspices of that TTQAP. The TTR instructs SRNL to conduct an error evaluation of anion measurements generated by the DWPF Laboratory using Ion Chromatography (IC) performed on SME samples. The anions of interest include nitrate, oxalate, and formate. Recent measurements of SME samples for these anions as well as measurements of total organic carbon (TOC) were provided to SRNL by DWPF Laboratory Operations (Lab OPS) personnel for this evaluation. This work was closely coordinated with the efforts of others within SRNL that are investigating the Chemical Process Cell (CPC) contributions to the melter flammability. The objective of that investigation was to develop a more comprehensive melter flammability control strategy that when implemented in DWPF will rely on process measurements. Accounting for the uncertainty of the measurements is necessary for successful implementation. The error evaluations conducted as part of this task will facilitate the integration of appropriate uncertainties for the

  5. Porphyrin Analogues of a Trityl Cation and Anion.

    Science.gov (United States)

    Kato, Kenichi; Kim, Woojae; Kim, Dongho; Yorimitsu, Hideki; Osuka, Atsuhiro

    2016-05-17

    Porphyrin-stabilized meso- or β-carbocations were generated upon treatment of the corresponding bis(4-tert-butylphenyl)porphyrinylcarbinols with trifluoroacetic acid (TFA). Bis(4-tert-butylphenyl)porphyrinylcarbinols were treated with TFA to generate the corresponding carbocations stabilized by a meso- or β-porphyrinyl group. The meso-porphyrinylmethyl carbocation displayed more effective charge delocalization with decreasing aromaticity compared with the β-porphyrinylmethyl carbocation. A propeller-like porphyrin trimer, tris(β-porphyrinyl)carbinol, was also synthesized and converted to the corresponding cation that displayed a more intensified absorption reaching over the NIR region. meso-Porphyrinylmethyl carbanion was generated as a stable species upon deprotonation of bis(4-tert-butylphenyl)(meso-porphyrinyl)methane with potassium bis(trimethylsilyl)amide (KHMDS) and [18]crown-6, whereas β-porphyrinylmethyl anions were highly unstable. PMID:26991021

  6. "Like-charge attraction" between anionic polyelectrolytes: molecular dynamics simulations.

    Science.gov (United States)

    Molnar, Ferenc; Rieger, Jens

    2005-01-18

    "Like-charge attraction" is a phenomenon found in many biological systems containing DNA or proteins, as well as in polyelectrolyte systems of industrial importance. "Like-charge attraction" between polyanions is observed in the presence of mobile multivalent cations. At a certain limiting concentration of cations, the negatively charged macroions cease to repel each other and even an attractive force between the anions is found. With classical molecular dynamics simulations it is possible to elucidate the processes that govern the attractive behavior with atomistic resolution. As an industrially relevant example we study the interaction of negatively charged carboxylate groups of sodium polyacrylate molecules with divalent cationic Ca2+ counterions. Here we show that Ca2+ ions initially associate with single chains of polyacrylates and strongly influence sodium ion distribution; shielded polyanions approach each other and eventually "stick" together (precipitate), contrary to the assumption that precipitation is initially induced by intermolecular Ca2+ bridging. PMID:15641856

  7. Preparation of anionic polyurethane nanoparticles and blood compatible behaviors.

    Science.gov (United States)

    Zhu, Qinshu; Wang, Yan; Zhou, Min; Mao, Chun; Huang, Xiaohua; Bao, Jianchun; Shen, Jian

    2012-05-01

    The anionic polyurethane nanoparticles (APU-NPs) were obtained by an emulsion polymerization method. It was found that the average size of the prepared APU-NPs is about 84 nm, and the APU-NPs have zeta-potential of -38.9 mV. The bulk characterization of synthesized APU-NPs was investigated by FTIR. The blood compatibility of APU-NPs was characterized by in vitro for coagulation tests, complement activation, platelet activation, cytotoxicity experiments, and hemolysis assay. The results showed that the APU-NPs synthesized in this paper are blood compatible with low level of cell cytotoxicity, and the results were significant for their potential use in vivo. PMID:22852346

  8. Anion Sensors as Logic Gates: A Close Encounter?

    Science.gov (United States)

    Madhuprasad; Bhat, Mahesh P; Jung, Ho-Young; Losic, Dusan; Kurkuri, Mahaveer D

    2016-04-25

    Computers have become smarter, smaller, and more efficient due to the downscaling of silicon-based components. Top-down miniaturisation of silicon-based computer components is fast reaching its limitations because of physical constraints and economical non-feasibility. Therefore, the possibility of a bottom-up approach that uses molecules to build nano-sized devices has been initiated. As a result, molecular logic gates based on chemical inputs and measurable optical outputs have captured significant attention very recently. In addition, it would be interesting if such molecular logic gates could be developed by making use of ion sensors, which can give significantly sensitive output information. This review provides a brief introduction to anion receptors, molecular logic gates, a comprehensive review on describing recent advances and progress on development of ion receptors for molecular logic gates, and a brief idea about the application of molecular logic gates. PMID:26890404

  9. Preliminary Testing For Anionic, Cationic and Non-ionic

    Directory of Open Access Journals (Sweden)

    Bokic, Lj.

    2007-11-01

    Full Text Available Detergents present a major environmental problem due to large quantities of surfactants released from laundries. For this reason, it is important to apply an appropriate analytical method for their determination. In this work, we propose two simple, fast and inexpensive analytical methods for anionic, cationic and non-ionic surfactant determination: thin layer chromatography (TLC separation for qualitative screening and quantitative potentiometric determination with ion-selective electrodes. These methods have been chosen because of their many advantages: rapidity, ease of operation, low cost of analysis and a wide variety of TLC application possibilities. The advantage of potentiometric titration is its very high degree of automation and very low detection limits obtained with different ion-selective electrodes applied for different surfactants.

  10. IR spectroscopy of gaseous fluorocarbon ions: The perfluoroethyl anion

    Energy Technology Data Exchange (ETDEWEB)

    Crestoni, Maria Elisa; Chiavarino, Barbara [Dipartimento di Chimica e Tecnologie del Farmaco, Universita di Roma ' La Sapienza' , P. le A. Moro 5, I-00185 Roma (Italy); Lemaire, Joel; Maitre, Philippe [Universite Paris Sud, Laboratoire de Chimie Physique - UMR8000 CNRS, Faculte des Sciences - Batiment 350, 91405 Orsay Cedex (France); Fornarini, Simonetta, E-mail: simonetta.fornarini@uniroma1.it [Dipartimento di Chimica e Tecnologie del Farmaco, Universita di Roma ' La Sapienza' , P. le A. Moro 5, I-00185 Roma (Italy)

    2012-04-04

    Highlights: Black-Right-Pointing-Pointer C{sub 2}F{sub 5}{sup -} ions are formed by dissociative electron capture in perfluoropropane. Black-Right-Pointing-Pointer Both their reactivity towards neutrals and IRMPD spectroscopy are investigated. Black-Right-Pointing-Pointer The sampled C{sub 2}F{sub 5}{sup -} ions are best described as covalently bound pentafluoroethyl anions. - Abstract: The first IR spectrum of a perfluorinated carbanion has been obtained in the gas phase by IRMPD spectroscopy. Quantum chemical calculations at the MP2/cc-pVTZ level were performed yielding the optimized geometries and IR spectra for a covalently bound C{sub 2}F{sub 5}{sup -} species and for conceivable loosely bound F{sup -}(C{sub 2}F{sub 4}) complexes. Both the computational results and the IR characterization point to a covalent structure for the assayed species in agreement with the reactivity pattern displayed with selected neutrals.

  11. Adsorption of Anionic Dyes onto Chitosan-modified Diatomite

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ge-shan; XUE Hong-hai; TANG Xiao-jian; PENG Fei; KANG Chun-li

    2011-01-01

    The purpose of this work is to study the possibility of anionic dyes Reactive Red M-8B(RR)and Direct Green B(DG)adsorbed on chitosan-modified diatomite.The characteristics of adsorbent,adsorption isotherms and the influence of adsorption time,temperature and pH were researched in this work.The results show that the modified diatomite had a much better adsorption capability than the natural diatomite.The adsorption capacities of chitosan-modified diatomite for RR and DG were 94.46 and 137.0 mg/g,respectively.Both adsorption time and adsorption temperature provided a positive effect on the dye adsorption.Within the experimental pH range,the adsorbance was enhanced at lower pH but reduced sharply at high pH.On the basis of the experimental results and discussion,electrostatic attraction is considered as the main mechanism of this chemisorption.

  12. Anion formation in sputter ion sources by neutral resonant ionization

    Science.gov (United States)

    Vogel, J. S.

    2016-02-01

    Focused Cs+ beams in sputter ion sources create mm-diameter pits supporting small plasmas that control anionization efficiencies. Sputtering produces overwhelmingly neutral products that the plasma can ionize as in a charge-change vapor. Electron capture between neutral atoms rises as the inverse square of the difference between the ionization potential of the Cs state and the electron affinity of the sputtered atom, allowing resonant ionization at very low energies. A plasma collision-radiation model followed electronic excitation up to Cs(7d). High modeled Cs(7d) in a 0.5 mm recess explains the 80 μA/mm2 C- current density compared to the 20 μA/mm2 from a 1 mm recess.

  13. Analytic description of dipole-bound anion photodetachment

    International Nuclear Information System (INIS)

    An analytical model for a dipole-bound anion (DBA) is proposed based on the exactly solvable three-dimensional Schroedinger equation for the excess electron bound by dipole potential of the parent neutral molecule (NM) in the Born-Oppenheimer approximation. The model gives reasonable analytical approximation for the dependence of the DBA binding energy on the NM dipole moment previously found numerically by many authors. The cross section of one-photon photodetachment of DBA is calculated in explicit analytical form. In the limit of high photon frequency, ω, the calculated cross-section displays ∼ω-2 behavior, which agrees perfectly with the experimental data [Bailey et al., J. Chem. Phys 104, 6976 (1996)]. At the threshold, the cross section demonstrates Gailitis-Damburg oscillations. Numerical dependence is provided for the maximal value of the cross section as a function of the NM dipole moment and the binding energy of the excess electron

  14. Alkaline direct alcohol fuel cells using an anion exchange membrane

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, Koji; Iriyama, Yasutoshi; Abe, Takeshi; Ogumi, Zempachi [Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Matsuoka, Masao [Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577 (Japan)

    2005-10-04

    Alkaline direct alcohol fuel cells using an OH-form anion exchange membrane and polyhydric alcohols were studied. A high open circuit voltage of ca. 800mV was obtained for a cell using Pt-Ru/C (anode) and Pt/C (cathode) at 323K, which was about 100-200mV higher than that for a DMFC using Nafion{sup R}. The maximum power densities were in the order of ethylene glycol>glycerol>methanol>erythritol>xylitol. Silver catalysts were used as a cathode catalyst to fabricate alkaline fuel cells, since silver catalyst is almost inactive in the oxidation of polyhydric alcohols. Alkaline direct ethylene glycol fuel cells using silver as a cathode catalyst gave excellent performance because higher concentrations of fuel could be supplied to the anode. (author)

  15. Anion exchange kinetics of uranium in sulphate media

    International Nuclear Information System (INIS)

    Experiments have shown that the sorption of uranium from acidic sulphate solutions onto strong base-anion exchange resins is particle diffusion controlled in the uranium concentration range 0.0001 to 0.004 M. A simplified diffusion model, based on Fick's Law, fits the kinetic data at each concentration. The rate of sorption falls significantly at lowered solution concentration. This corresponds with a lowered equilibrium loading of uranium and can be predicted with the Nernst-Planck equations using the measured self diffusion coefficient of uranium (1.65 x 10-8 cm2/s) and sulphate ions. The importance of this lowering of uranium sorption on the design of ion exchange equipment is stressed. (author)

  16. Experimental studies of single-photon photodetachment of atomic anions

    Science.gov (United States)

    Duvvuri, Srividya S.

    Laser photodetachment electron spectroscopy (LPES) has been used to study the structure of the terbium anion. The data was analyzed assuming that the terbium anion forms in dysprosium-like states. Using this assumption, the electron affinity of Tb([Xe]4f96s 2 6 Ho15/2 ) equals 1.98 +/- 0.10 eV, and the ground state of the terbium anion is assigned to the Dy-like Tb-([Xe]4f 106s2 5I 8) electronic configuration. At lust two bound excited states of Tb - are also evident in the photoelectron kinetic energy spectra, with binding energies of 0.449 +/- 0.01 and 1.67 +/- 0.07 eV relative to the Tb(6 Ho15/2 ) ground state. The energy scale of each Tb- photoelectron spectrum way calibrated using reference photoelectron peaks from 12 C-, 16O- and 23Na-, which have well known binding energies [1]. Photoelectron angular distribution measurements following the single-photon photodetachment of the lanthanide anions Tb- and Lu - are also presented. The asymmetry parameters were determined from the non-linear least-square fits of the photoelectron yields as a function of the angle between the photon polarization vector and the photoelectron momentum vector of the collected photoelectrons. The measurements indicated the single-photon photodetachment process hnu + Tb -([Xe]4f106s 2 5I8) → Tb([Xe]4 f96s2 6) Ho15/2 + e - has beta values of 1.51 +/- 0.08 and 1.35 +/- 0.08 at wavelengths of 514.5 and 488 nm, respectively. For Lu -, the fine-structure resolved photodetachment process hnu +Lu-([Xe]4f146s 26p5d 1D 2) → Lu([Xe]4f145 d6s2 2D 3/2) + e-, has been measured at wavelength of 532 nm yielding beta = 0.8 +/- 0.1, supporting the assertion that Lu - forms via the attachment of a 6p-electron to the neutral Lu atom [2]. Finally, photodetachment cross sections and the angular distributions of photo-electrons produced by the single-photon detachment of the Fe - and Cu- have also been measured at discrete visible photon wavelengths. From the measured photodetachment cross sections, the

  17. N-Arylazetidines: Preparation through Anionic Ring Closure.

    Science.gov (United States)

    Quinodoz, Pierre; Drouillat, Bruno; Wright, Karen; Marrot, Jérôme; Couty, François

    2016-04-01

    We report herein an efficient synthesis of diversely substituted N-aryl-2-cyanoazetidines based on an anionic ring-closure reaction. These compounds can be prepared from β-amino alcohols in enantiomerically pure form through a three-step sequence involving (i) copper-catalyzed N-arylation, (ii) N-cyanomethylation of the secondary aniline, and (iii) one-pot mesylation followed by ring closure induced by a base. This high-yielding sequence gives access to azetidines with a predictable and adjustable substitution pattern and also with predictable diastereoselectivity. These compounds are susceptible to multiple further derivatizations through Suzuki coupling or nitrile transformation, thus appearing as valuable new scaffolds for medicinal chemistry. Their rigid shape, featuring an almost planar N-arylamine and a planar four-membered ring, was revealed by both AM1 calculations and X-ray crystallography. PMID:26932242

  18. Anion formation in sputter ion sources by neutral resonant ionization

    International Nuclear Information System (INIS)

    Focused Cs+ beams in sputter ion sources create mm-diameter pits supporting small plasmas that control anionization efficiencies. Sputtering produces overwhelmingly neutral products that the plasma can ionize as in a charge-change vapor. Electron capture between neutral atoms rises as the inverse square of the difference between the ionization potential of the Cs state and the electron affinity of the sputtered atom, allowing resonant ionization at very low energies. A plasma collision-radiation model followed electronic excitation up to Cs(7d). High modeled Cs(7d) in a 0.5 mm recess explains the 80 μA/mm2 C− current density compared to the 20 μA/mm2 from a 1 mm recess

  19. The removal of anionic surfactants from water in coagulation process.

    Science.gov (United States)

    Kaleta, Jadwiga; Elektorowicz, Maria

    2013-01-01

    This paper presents the results of a laboratory study on the effectiveness of the coagulation process in removing surfactants from water. The application of traditional coagulants (aluminium sulfate and iron chlorides) has not brought satisfactory results, the reduction in anionic surfactant (AS) content reached 7.6% and 10%, respectively. Adding cationic polyelectrolyte (Zetag-50) increased the removal efficiency to 24%. Coagulation using a polyelectrolyte alone proved to be more efficient, the reduction in surfactant content fluctuated at a level of about 50%. Complete surfactant removal was obtained when powdered activated carbon was added 5 minutes before the basic coagulant to the coagulation process. The efficiency of surfactant coagulation also increased after the application of powdered clinoptilolite, but to a smaller degree. Then the removal of AS was found to be improved by dosing powdered clinoptilolite simultaneously or with short delay after the addition of the basic coagulant. PMID:23837351

  20. Benzimidazole-derived anion for lithium-conducting electrolytes

    Science.gov (United States)

    Niedzicki, Leszek; Oledzki, Piotr; Bitner, Anna; Bukowska, Maria; Szczecinski, Przemyslaw

    2016-02-01

    In this work we announce new lithium salt of 5,6-dicyano-2-(trifluoromethyl)benzimidazolide (LiTDBI) designed for application in lithium conductive electrolytes. It was synthesized and completely characterized by NMR techniques. Studies show salt's thermal stability up to 270 °C and electrochemical stability in liquid solvents up to +4.7 V vs. metallic lithium anode. Basic characterization of electrolytes made with this salt show conductivity over 1 mS cm-1 and unusually high transference number at high concentrations (0.74 in EC:DMC 1:2 ratio mixture) along with low onset of conductivity peak. As a final proof of concept, cycling in half-cell was performed and electrolyte based on LiTDBI showed perfect capacity retention. Such properties show remarkable progress in creating efficient lithium-conducting electrolytes with use of weakly-coordinating anions.

  1. Speciation and transport of radionuclides in ground water

    International Nuclear Information System (INIS)

    Studies of the chemical speciation of a number of radionuclides migrating in a slightly contaminated ground water plume are identifying the most mobile species and providing an opportunity to test and/or validate geochemical models of radionuclide transport in ground waters. Results to date have shown that most of the migrating radionuclides are present in anionic or nonionic forms. These include anionic forms of 55Fe, 60Co, /sup 99m/Tc, 106Ru, 131I, and nonionic forms of 63Ni and 125Sb. Strontium-70 and a small fraction of the mobile 60Co are the only cationic radionuclides which have been detected moving in the ground water plume beyond 30 meters from the source. A comparison of the observed chemical forms with the predicted species calculated from modeling thermodynamic data and ground water chemical parameters has indicated a good agreement for most of the radioelements in the system, including Tc, Np, Cs, Sr, Ce, Ru, Sb, Zn, and Mn. The discrepancies between observed and calculated solutions species were noted for Fe, Co, Ni and I. Traces of Fe, Co, and Ni were observed to migrate in anionic or nonionic forms which the calculations failed to predict. These anionic/nonionic species may be organic complexes having enhanced mobility in ground waters. The radioiodine, for example, was shown to behave totally as an anion but further investigation revealed that 49-57% of this anionic iodine was organically bound. The ground water and aqueous extracts of trench sediments contain a wide variety of organic compounds, some of which could serve as complexing agents for the radionuclides. These results indicate the need for further research at a variety of field sites in defining precisely the chemical forms of the mobile radionuclide species, and in better understanding the role of dissolved organic materials in ground water transport of radionuclides

  2. Electro membrane extraction of biological anions with ion chromatographic analysis.

    Science.gov (United States)

    Tan, Tsze Yin; Basheer, Chanbasha; Ng, Kai Perng; Lee, Hian Kee

    2012-08-20

    A simple and sensitive single step electro membrane extraction (EME) procedure was demonstrated for biological organic anions with determination by ion chromatography (IC). Nitrite, adipate, oxalate, iodide, fumarate, thiocyanate and perchlorate were extracted from aqueous donor solutions, across a supported liquid membrane (SLM) consisting of methanol impregnated in the walls of a porous polypropylene membrane bag and into an alkaline aqueous acceptor solution in the lumen of the propylene envelope by the application of potential of 12V applied across the SLM. The acceptor solution was analyzed by IC. Parameters affecting the extraction performance such as type of SLM, extraction time, pH of the donor and acceptor solution, and extraction voltage were studied. The most favorable EME conditions were methanol as the SLM, extraction time of 5min, pH of acceptor and sample solutions of 12 and 4, respectively, and a voltage of 12V. Portable 12V batteries were used in the study. Under these optimized conditions, all anions had enrichment factors ranging from 3.6 to 36.2 with relative standard deviations (n=3) of between 6.6 and 17.5%. Good linearity ranging from 0.1 to 10μgmL(-1) with coefficients of correlation (r) of between 0.9981 and 0.9996 were obtained. The limits of detection of the EME-IC method were from 0.01 to 0.14μgmL(-1). The developed methodology was applied to amniotic fluid samples to evaluate the feasibility of the method for real applications. PMID:22819047

  3. Enhanced DOC removal using anion and cation ion exchange resins.

    Science.gov (United States)

    Arias-Paic, Miguel; Cawley, Kaelin M; Byg, Steve; Rosario-Ortiz, Fernando L

    2016-01-01

    Hardness and DOC removal in a single ion exchange unit operation allows for less infrastructure, is advantageous for process operation and depending on the water source, could enhance anion exchange resin removal of dissolved organic carbon (DOC). Simultaneous application of cationic (Plus) and anionic (MIEX) ion exchange resin in a single contact vessel was tested at pilot and bench scales, under multiple regeneration cycles. Hardness removal correlated with theoretical predictions; where measured hardness was between 88 and 98% of the predicted value. Comparing bench scale DOC removal of solely treating water with MIEX compared to Plus and MIEX treated water showed an enhanced DOC removal, where removal was increased from 0.5 to 1.25 mg/L for the simultaneous resin application compared to solely applying MIEX resin. A full scale MIEX treatment plant (14.5 MGD) reduced raw water DOC from 13.7 mg/L to 4.90 mg/L in the treated effluent at a bed volume (BV) treatment rate of 800, where a parallel operation of a simultaneous MIEX and Plus resin pilot (10 gpm) measured effluent DOC concentrations of no greater than 3.4 mg/L, even at bed volumes of treatment 37.5% greater than the full scale plant. MIEX effluent compared to simultaneous Plus and MIEX effluent resulted in differences in fluorescence intensity that correlated to decreases in DOC concentration. The simultaneous treatment of Plus and MIEX resin produced water with predominantly microbial character, indicating the enhanced DOC removal was principally due to increased removal of terrestrially derived organic matter. The addition of Plus resin to a process train with MIEX resin allows for one treatment process to remove both DOC and hardness, where a single brine waste stream can be sent to sewer at a full-scale plant, completely removing lime chemical addition and sludge waste disposal for precipitative softening processes. PMID:26624231

  4. Formation of secondary minerals and uptake of various anions under naturally-occurring hyper-alkaline conditions in Oman - 16344

    International Nuclear Information System (INIS)

    In Japanese transuranic (TRU) waste disposal facilities, 129I is the most important key nuclide for the long-term safety assessment. Thus, the Kd values of I to natural minerals are important factor in the safety assessment. However, the degradation of cement materials in the repositories can produce high pH pore fluid which can affect the anion transport behavior. Therefore, it is necessary to understand the behavior of anions such as I- under the hyper-alkaline conditions. The natural hyper-alkaline spring water (pH>11) in the Oman ophiolite is known to be generated from the partly serpentinized peridotites. The spring water is characteristically hyper-alkaline, reducing, low-Mg, Si and HCO3-, and high-Ca, while the river water is moderately alkaline, oxidizing, high-Mg and HCO3-. The mixing of these spring and river water resulted in the formation of secondary minerals. In the present study, the naturally occurring hyper-alkaline conditions near the springs in Oman were used as natural analogue for the interaction between cement pore fluid and natural Mg-HCO3- groundwater. The present aim of this paper is to examine the conditions of secondary mineral formation and the anion uptake capacity of these mineral in this system. Water and precipitate samples were collected from the different locations around the spring vent to identify the effect of mixing ratios between spring and river water on mineral composition and water-mineral distribution coefficient of various anions. On-site synthesis was also carried out to support these data quantitatively. Aragonite was observed in all precipitates, while calcite, brucite and Mg-Al hydrotalcite-like compounds (HTlc) were also determined in some samples. Calcite was observed only closed to the springs. At locations far from the springs, calcite formation was inhibited due to high-Mg fluid from river water. Brucite was observed from the springs with relatively low-Al concentration and HTlc was the opposite. During the

  5. Anion release and uptake kinetics: structural changes of layered 2-dimensional ZnNiHN upon uptake of acetate and chlorinated acetate anions.

    Science.gov (United States)

    Machingauta, Cleopas; Hossenlopp, Jeanne M

    2013-12-01

    X-ray diffraction and UV-vis spectroscopy were used for the investigation of ion exchange reaction kinetics of nitrates with acetate (Ac), chloro acetate (ClAc), dichloro acetate (dClAc) and trichloro acetate (tClAc) anions, using zinc nickel hydroxy nitrate (ZnNiHN) as the exchange precursor. The exchange reactions conducted at 24, 30, 40 and 50°C revealed that rate constants were inversely related to the calculated anion electronic spatial extent (ESE), while a direct relationship between rate constants and the average oxygen charges was observed. Temporal solid phase structural transformations were shown to be affected by the nature of the guest anions. The amount of nitrates released into solution has been shown to decrease as the guest anions became more chlorinated. Use of isoconversional approach revealed that activation energies changed significantly with α during dClAc intercalation than for the other anions. The topotactic intercalation of the guest anions, except dClAc, followed the Avrami-Erofe'ev kinetic model for the entire reaction progress. PMID:24054447

  6. A new family of anionic organic–inorganic hybrid doughnut-like nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhuxiu; Gao, Wen-Yang; Wojtas, Lukasz; Zhang, Zhenjie; Zaworotko, Michael J. (Limerick); (USF)

    2015-06-15

    A family of soluble organic–inorganic hybrid doughnut-like anions, hydoughnuts, has been prepared by the self-assembly of polyoxovanadate anions and 1,3-benzenedicarboxylate (bdc) linkers. Derivatives of the parent hydoughnut, [(V₄O₈Cl)₄(bdc)₈]⁴⁻, can be obtained by changing the counter-ion or by using a variant of bdc.

  7. A C2-symmetric ratiometric fluorescence and colorimetric anion sensor based on pyrrole derivative

    International Nuclear Information System (INIS)

    A C2-symmetric fluorescence and colorimetric anion sensor (1) based on pyrrole derivative was designed and synthesized according to binding site-signaling subunit approach. The compound 1 was easily prepared by reaction of pyrrole-2,5-dicarboxaldehyde with 4-nitrophenylhydrazine in ethanol (yield=78%). In DMSO, the sensor 1 exhibited a visible color change from red to brown upon exposure to anions such as AcO- and F-; however, no obvious color changes were observed when the other tested anions (e. g. H2PO4-, Cl-, Br- and I-) were added. There was a significant redshift (Δλmax=160 nm) in UV-vis spectrum during UV-vis spectral titrations. In particular, the sensor 1 showed ratiometric fluorescence responses to anions. - Highlights: → C2-symmetric fluorescence and colorimetric anion sensor based on pyrrole derivative was designed and synthesized according to binding site-signaling subunit approach. → The sensor was easily prepared by reaction of pyrrole-2,5-dicarboxaldehyde with 4-nitrophenylhydrazine in ethanol (yield=78%). → In DMSO, the sensor exhibited a visible color change from red to brown upon exposure to anions such as AcO- and F-, however, no obvious color changes were observed when the other anions tested (e. g. H2PO4-, Cl-, Br- and I-) were added. → The sensor showed ratiometric fluorescence responses to anions.

  8. The saccharinate anion: a versatile and fascinating ligand in coordination chemistry

    Directory of Open Access Journals (Sweden)

    Enrique J. Baran

    2005-03-01

    Full Text Available The saccharinate anion, obtained by deprotonation of the N-H moiety of saccharin (o-sulfobenzimide is a very versatile and polyfunctional ligand in coordination chemistry. In this review the different forms of metal-to-ligand interactions involving this anion and some other coordination peculiarities are briefly discussed on the basis of some selected examples.

  9. CO{sub 2} binding in the (quinoline-CO{sub 2}){sup −} anionic complex

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Jacob D.; Buytendyk, Allyson M.; Wang, Yi; Bowen, Kit H., E-mail: kbowen@jhu.edu [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Kim, Seong K. [Department of Chemistry, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2015-06-21

    We have studied the (quinoline-CO{sub 2}){sup −} anionic complex by a combination of mass spectrometry, anion photoelectron spectroscopy, and density functional theory calculations. The (quinoline-CO{sub 2}){sup −} anionic complex has much in common with previously studied (N-heterocycle-CO{sub 2}){sup −} anionic complexes both in terms of geometric structure and covalent bonding character. Unlike the previously studied N-heterocycles, however, quinoline has a positive electron affinity, and this provided a pathway for determining the binding energy of CO{sub 2} in the (quinoline-CO{sub 2}){sup −} anionic complex. From the theoretical calculations, we found CO{sub 2} to be bound within the (quinoline-CO{sub 2}){sup −} anionic complex by 0.6 eV. We also showed that the excess electron is delocalized over the entire molecular framework. It is likely that the CO{sub 2} binding energies and excess electron delocalization profiles of the previously studied (N-heterocycle-CO{sub 2}){sup −} anionic complexes are quite similar to that of the (quinoline-CO{sub 2}){sup −} anionic complex. This class of complexes may have a role to play in CO{sub 2} activation and/or sequestration.

  10. Preassembly-driven ratiometric sensing of H2PO4(-) anions in organic and aqueous environments.

    Science.gov (United States)

    Gong, Wei-tao; Na, Duo; Fang, Le; Mehdi, Hassan; Ning, Gui-ling

    2015-02-21

    Gemini surfactant-like receptor is designed and synthesized. The special preassembly phenomenon of in a nonpolar solvent facilitates the novel ratiometric fluorescence sensing of H2PO4(-)via an anion-induced reassembly process in organic solvents and an anion-induced disassembly process in water. PMID:25563510

  11. The anionic basis of fluid secretion by the rabbit mandibular salivary gland

    DEFF Research Database (Denmark)

    Case, R M; Hunter, M; Novak, I;

    1984-01-01

    The role played by anions in salivary secretion has been studied in experiments on the isolated, perfused mandibular gland of the rabbit, in which perfusate Cl- and/or HCO3- were replaced by other anions. Replacement of Cl- with Br- had no significant effect on salivary secretion rate, but...

  12. Specificity of anion-binding in the substrate-pocket ofbacteriorhodopsin

    Energy Technology Data Exchange (ETDEWEB)

    Facciotti, Marc T.; Cheung, Vincent S.; Lunde, Christopher S.; Rouhani, Shahab; Baliga, Nitin S.; Glaeser, Robert M.

    2003-08-30

    The structure of the D85S mutant of bacteriorhodopsin with a nitrate anion bound in the Schiff-base binding site, and the structure of the anion-free protein have been obtained in the same crystal form. Together with the previously solved structures of this anion pump, in both the anion-free state and bromide-bound state, these new structures provide insight into how this mutant of bacteriorhodopsin is able to bind a variety of different anions in the same binding pocket. The structural analysis reveals that the main structural change that accommodates different anions is the repositioning of the polar side-chain of S85. On the basis of these x-ray crystal structures, the prediction is then made that the D85S/D212N double mutant might bind similar anions and do so over a broader pH range than does the single mutant. Experimental comparison of the dissociation constants, K{sub d}, for a variety of anions confirms this prediction and demonstrates, in addition, that the binding affinity is dramatically improved by the D212N substitution.

  13. Anionic polymerization and polyhomologation: An ideal combination to synthesize polyethylene-based block copolymers

    KAUST Repository

    Zhang, H.

    2013-08-07

    A novel one-pot methodology combining anionic polymerization and polyhomologation, through a "bridge" molecule (BF3OEt 2), was developed for the synthesis of polyethylene (PE)-based block copolymers. The anionically synthesized macroanion reacts with the "bridge" molecule to afford a 3-arm star (trimacromolecular borane) which serves as an initiator for the polyhomologation. 2013 The Royal Society of Chemistry.

  14. CO2 binding in the (quinoline-CO2)− anionic complex

    International Nuclear Information System (INIS)

    We have studied the (quinoline-CO2)− anionic complex by a combination of mass spectrometry, anion photoelectron spectroscopy, and density functional theory calculations. The (quinoline-CO2)− anionic complex has much in common with previously studied (N-heterocycle-CO2)− anionic complexes both in terms of geometric structure and covalent bonding character. Unlike the previously studied N-heterocycles, however, quinoline has a positive electron affinity, and this provided a pathway for determining the binding energy of CO2 in the (quinoline-CO2)− anionic complex. From the theoretical calculations, we found CO2 to be bound within the (quinoline-CO2)− anionic complex by 0.6 eV. We also showed that the excess electron is delocalized over the entire molecular framework. It is likely that the CO2 binding energies and excess electron delocalization profiles of the previously studied (N-heterocycle-CO2)− anionic complexes are quite similar to that of the (quinoline-CO2)− anionic complex. This class of complexes may have a role to play in CO2 activation and/or sequestration

  15. Sediment Transport

    DEFF Research Database (Denmark)

    Liu, Zhou

    Flow and sediment transport are important in relation to several engineering topics, e.g. erosion around structures, backfilling of dredged channels and nearshore morphological change. The purpose of the present book is to describe both the basic hydrodynamics and the basic sediment transport...... mechanics. Chapter 1 deals with fundamentals in fluid mechanics with emphasis on bed shear stress by currents, while chapter 3 discusses wave boundary layer theory. They are both written with a view to sediment transport. Sediment transport in rivers, cross-shore and longshore are dealt with in chapters 2...

  16. Two Multi-armed Neutral Receptors for α, ω-Dicarboxylate Anions

    Institute of Scientific and Technical Information of China (English)

    WU, Jin-Long; HE, Yong-Bing; WEI, Lan-Hua; LIU, Shun-Ying; XU, Kuo-Xi; MENG, Ling-Zhi

    2006-01-01

    Two new multi-armed neutral receptors 1 and 2 containing thiourea and amide groups were synthesized by simple steps in good yields. Receptors 1 and 2 have a better selectivity and higher association constants for malonate anion than other anions examined by the present work. In particular, distinct color changes were observed upon addition of dicarboxylate anions to the solution of 1 in DMSO. The UV-Vis and fluorescence spectra data indicate that a 1: 2 stoichiometry complex was formed between compound 1 or 2 and dicarboxylate anions of shorter carbon chain, and a 1: 1 stoichiometry complex was formed between compound 1 or 2 and dicarboxylate anions of longer carbon chain through hydrogen bonding interactions.

  17. Action spectroscopy of gas-phase carboxylate anions by multiple photon IR electron detachment/attachment

    CERN Document Server

    Steill, Jeffrey D

    2008-01-01

    We report on a form of gas-phase anion action spectroscopy based on infrared multiple photon electron detachment and subsequent capture of the free electrons by a neutral electron scavenger in a Fourier Transform Ion Cyclotron Resonance (FTICR) mass spectrometer. This method allows one to obtain background-free spectra of strongly bound anions, for which no dissociation channels are observed. The first gas-phase spectra of the acetate and propionate anions are presented using SF6 as electron scavenger and a free electron laser as source of intense and tunable infrared radiation. To validate the method, we compare infrared spectra obtained through multiple photon electron detachment/attachment and multiple photon dissociation for the benzoate anion. In addition, different electron acceptors are used, comparing both associative and dissociative electron capture. The relative energies of dissociation (by CO2 loss) and electron detachment are investigated for all three anions by DFT and CCSD(T) methods. DFT calcu...

  18. Effect of anionic salts on selenium metabolism in nonlactating, pregnant dairy cows.

    Science.gov (United States)

    Gant, R G; Sanchez, W; Kincaid, R L

    1998-06-01

    The objective of this trial was to determine whether anionic salts in the diets of nonlactating, pregnant cows for 14 to 21 d prepartum affected measures of Se status. One of three dietary treatments (control, anionic salts, and anionic salts plus Se) was administered to 34 nonlactating, pregnant cows using a completely randomized design with repeated measures. The anionic salts were delivered via gelatin capsules that were administered orally in two equal amounts per day, and the Se (3 mg/d) was administered via an intraruminal bolus. The incidence of milk fever among cows was not significantly different across dietary treatments. The severity of hypocalcemia as indicated by concentrations of ionized Ca in serum collected milk fever without danger of significantly reducing the transfer of Se from the dam to the calf and without compromising the Se status of the cow when the anionic salts are limited to administration for 14 to 21 d before calving. PMID:9684171

  19. A procedure for reducing the concentration of hydrogen ions in acid anionic eluate and equipment therefore

    International Nuclear Information System (INIS)

    The method is described of reducing the concentration of hydrogen ions in acid anionic eluate produced in the separation of uranium or other metals, in which anion exchanger elution, precipitation, filtration and precipitate and anion exchanger washing are used. The technological line for such elution comprises at least one ion exchange column and at least one container. They together form the first and the second stages of preparation of the acid anion elution solution, the sorption-elution separation of hydrogen ions on an cation exchanger being inserted between them. The preparation of the solution is divide into two stages. In the first stage, the acid and part of the solution for the preparation of the acid anion elution solution are supplied. The resulting enriched acid elution solution is fe onto the cation exchanger where the hydrogen ion concentration i reduced. It is then carried into the second stage where it is mixed with the remaining part of the solution. (B.S.)

  20. Anion-Exchange Properties of Trifluoroacetate and Triflate Salts of N-Alkylammonium Resorcinarenes.

    Science.gov (United States)

    Pan, Fangfang; Beyeh, Ngong Kodiah; Bertella, Stefania; Rissanen, Kari

    2016-03-01

    The synthesis of N-benzyl- and N-cyclohexylammonium resorcinarene trifluoroacetate (TFA) and triflate (OTf) salt receptors was investigated. Solid-state analysis by single-crystal X-ray diffraction revealed that the N-alkylammonium resorcinarene salts (NARSs) with different upper substituents had different cavity sizes and different affinities for anions. Anion-exchange experiments by mixing equimolar amounts of N-benzylammonium resorcinarene trifluoroacetate and N-cyclohexylammonium resorcinarene triflate, as well as N-benzylammonium resorcinarene triflate and N-cyclohexylammonium resorcinarene trifluoroacetate showed that the NARS with flexible benzyl groups preferred the larger OTf anion, whereas the rigid cyclohexyl groups preferred the smaller TFA anions. The anion-exchange processes were confirmed in the solid state by single-crystal and powder X-ray diffraction experiments and in the gas phase by electrospray ionization mass spectrometry. PMID:26749383

  1. Controlled Release Kinetics in Hydroxy Double Salts: Effect of Host Anion Structure

    Directory of Open Access Journals (Sweden)

    Stephen Majoni

    2014-01-01

    Full Text Available Nanodimensional layered metal hydroxides such as layered double hydroxides (LDHs and hydroxy double salts (HDSs can undergo anion exchange reactions releasing intercalated anions. Because of this, these metal hydroxides have found applications in controlled release delivery of bioactive species such as drugs and pesticides. In this work, isomers of hydroxycinnamate were used as model compounds to systematically explore the effects of anion structure on the rate and extent of anion release in HDSs. Following intercalation and subsequent release of the isomers, it has been demonstrated that the nature and position of substituent groups on intercalated anions have profound effects on the rate and extent of release. The extent of release was correlated with the magnitude of dipole moments while the rate of reaction showed strong dependence on the extent of hydrogen bonding within the layers. The orthoisomer showed a more sustained and complete release as compared to the other isomers.

  2. Sorption of Pu(IV) from nitric acid by bifunctional anion-exchange resins

    International Nuclear Information System (INIS)

    Anion exchange is attractive for separating plutonium because the Pu(IV) nitrate complex is very strongly sorbed and few other metal ions form competing anionic nitrate complexes. The major disadvantage of this process has been the unusually slow rate at which the Pu(IV) nitrate complex is sorbed by the resin. The paper summarizes the concept of bifunctional anion-exchange resins, proposed mechanism for Pu(IV) sorption, synthesis of the alkylating agent, calculation of Kd values from Pu(IV) sorption results, and conclusions from the study of Pu(IV) sorption from 7M nitric acid by macroporous anion-exchange resins including level of crosslinking, level of alkylation, length of spacer, and bifunctional vs. monofunctional anion-exchange resins

  3. Aprotic Heterocyclic Anion Triazolide Ionic Liquids - A New Class of Ionic Liquid Anion Accessed by the Huisgen Cycloaddition Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Robert L; Damodaran, Krishnan; Luebke, David; Nulwala, Hunaid

    2013-06-01

    The triazole core is a highly versatile heterocyclic ring which can be accessed easily with the Cu(I)-catalyzed Huisgen cycloaddition reaction. Herein we present the preparation of ionic liquids that incorporate a 1,2,3-triazolide anion. These ionic liquids were prepared by a facile procedure utilizing a base-labile pivaloylmethyl group at the 1-position, which can act as precursors to 1H- 4-substituted 1,2,3-triazole. These triazoles were then subsequently converted into ionic liquids after deprotonation using an appropriate ionic liquid cation hydroxide. The densities and thermal decompositions of these ionic liquids were measured. These novel ionic liquids have potential applications in gas separations and in metal-free catalysis.

  4. Transport Properties of the Organic Conductor (TMTSF)2BrO4: Evidence of Variable Range Hopping

    DEFF Research Database (Denmark)

    Mortensen, Kell; Jacobsen, Claus Schelde; Bechgaard, Klaus;

    1984-01-01

    A study of d.c. and microwave conductivity and thermoelectric power of the organic conductor (TMTSF)2BrO4 is presented. The transport properties are in qualitative agreement with charge transport via variable-range hopping among localized states. The localization is attributed to the anions, which...

  5. Improvement of barrier function and stimulation of colonic epithelial anion secretion by Menoease Pills

    Institute of Scientific and Technical Information of China (English)

    Jin-Xia Zhu; Ning Yang; Gui-Hong Zhang; Lai-Ling Tsang; Yu-Lin Gou; Hau-Yan Connie Wong; Yiu-Wa Chung; Hsiao-Chang Chan

    2004-01-01

    AIM: Menoease Pills (MP), a Chinese medicine-based new formula for postmenopausal women, has been shown to modulate the endocrine and immune systems[1]. The present study investigated the effects of MP and one of its active ingredients, ligustrazine, on epithelial barrier and ion transport function in a human colonic cell line, T84.METHODS: Colonic transepithelial electrophysiological characteristics and colonic anion secretion were studied using the short circuit current (ISC) technique. RT-PCR was used to examine the expression of cytoplasmic proteins associated with the tight junctions, ZO-1(zonula occludens-1) and ZO-2 (zonula occludens-2).RESULTS: Pretreatment of T84 cells with MP (15 μg/mL) for 72 h significantly increased basal potential difference,transepithelial resistance and basal ISC. RT-PCR results showed that the expressions of ZO-1 and ZO-2 were significantly increased after MP treatment, consistent with improved epithelial barrier function. Results of acute stimulation showed that apical addition of MP produced a concentrationdependent (10-5 000 μg/mL, EC50 = 293.9 μg/mL) increase in ISC. MP-induced ISC was inhibited by basolateral treatment with bumetanide (100 μmol/L), an inhibitor of the Na+-K+-2Cl- cotransporter, apical addition of Cl-channel blockers, diphenylamine-2, 2'-dicarboxylic acid (1 mmol/L) or glibenclamide (1 mmol/L), but not 4, 4'-diisothiocyanostilbene2, 2'-disulfonic acid or epithelial Na+ channel blocker,amiloride. The effect of MP on ZO-1 and ZO-2 was mimicked by Ligustrazine and the ligustrazine-induced ISC was also blocked by basolateral application of bumetanide and apical addition of diphenylamine-2, 2'-dicarboxylic acid or glibenclamide, and reduced by a removal of extracellular Cl-.CONCLUSION: The results of the present study suggest that MP and lligustrazine may improve epithelial barrier function and exert a stimulatory effect on colonic anion secretion, indicating the potential use of MP and its active ingredients

  6. Development and characterization of direct ethanol fuel cells using alkaline anion-exchange membranes

    Science.gov (United States)

    Lim, Peck Cheng

    2009-08-01

    Alkaline membrane fuel cell (AMFC) is a relatively new fuel cell technology that is generating considerable interests. It offers the electrocatalytic advantages of conventional alkaline fuel cells, and the manufacturing and cost advantages of solid polymer electrolyte fuel cells. This project was carried out to develop and characterize high performance membrane electrode assemblies (MEAs) for all-solid-state AMFCs. The primary fuel of interests is ethanol, but hydrogen was used in the development stages to facilitate the diagnostic and evaluation of the fuel cell performance. In the preliminary investigation, AMFC was assembled using off-the-shelf electrodes and anion-exchange membrane (AEM). It was found that the performance of AMFC operating on ethanol fuel was limited by a large high-frequency resistance (HFR) value. The advantage of using non-toxic ethanol fuel was also compromised by the need to add hydrazine and potassium hydroxide to the fuel blend. Subsequently, a high performance MEA was developed for an all-solid-state AMFC, in which liquid electrolyte or other additives were not required during the operation of the fuel cell. Ionomer was incorporated in the formulation of catalyst ink, and the catalyst ink was directly coated on the anion-exchange membrane (AEM). An ionomer content of 20 wt.% was found to be the optimum amount required in the catalyst layers. It was demonstrated that the AMFC generated a maximum power density of 365 mW/cm2 and 213 mW/cm 2 with the use of hydrogen/oxygen and hydrogen/pure air, respectively. The performance of the AMFC was also found to be influenced by exposure to carbon dioxide in the air. Hence, the CCMs were pre-treated in potassium hydroxide solution and pure oxygen was used to condition the fuel cell to maximize the power output from the AMFCs. Although satisfactory performance was demonstrated in the AMFC, its stability during cell operation remains a major issue. The poor stability was attributed to degradation of

  7. Effect of proquinazid and copper hydroxide on homeostasis of anions in winter wheat plants in generative phase of development

    Directory of Open Access Journals (Sweden)

    M. E. Riazanova

    2015-03-01

    Full Text Available The study deals with the effect of proquinazid and copper oxide application on structural characteristics and resistance of wheat to powdery mildew, as well as remobilisation and redistribution of anions pools at generative stage of development. The trial series was conducted in the experimental agricultural production of the Institute of Plant Physiology and Genetics, National Academy of Sciences of Ukraine. Field experiments were carried out with Smuglyanka variety of winter wheat. The trial series included the application of fungicides such as Talius (proquinazid, 200 g/L 0,25 L/ha and Kocide 2000 (copper hydroxide, 350 g/kg 150 and 300 g/ha, and combination of both fungicides. Sprays were applied at tillering stage in autumn in the first trial series and at tillering-booting stage in spring in the second one. Assessment of affected plants by powdery mildew was carried out visually in points. Anion concentration was determined with the use of ion chromatography. Application of fungicides at tillering stage increases the amount of productive stems in wheat plants. The highest effect was recorded for application of copper hydroxide at dose of 300 g/ha in autumn. Analysis of plants affected by powdery mildew shows that application of proquinazid and its composition with copper hydroxide provides sustained protection against Blumeria graminis (DC Speer. Application of fungicides at tillering stage contributes to increase of the pool of free nitrogen, phosphorus and sulfur anions in leaf tissues compared to control. These changes in anion composition may be caused by fungicide effect on activity of N, P, S transporters, as well as internal regulatory mechanisms of elements’ uptake by plants. Comparing the results of the autumn and spring application of fungicides should note the increase in concentration of free phosphates in wheat leaves in the 2nd trial with proquinazid and its composition with copper hydroxide. Accumulation of nitrogen in the

  8. Maritime Transport

    OpenAIRE

    Veenstra, A.W.

    2002-01-01

    This important volume brings together an authoritative selection of the leading papers on the subject of maritime transport. With a new introductory essay by the editors, the collection provides a thorough examination of the topics associated with this area, including maritime economics, transport law and policy.

  9. Neutron transport

    International Nuclear Information System (INIS)

    This bibliographical note presents a reference book which addresses the study of neutron transport in matter, the study of conditions for a chain reaction and the study of modifications of matter composition due to nuclear reactions. This book presents the main nuclear data, their measurement, assessment and processing, and the spallation. It proposes an overview of methods applied for the study of neutron transport: basic equations and their derived forms, deterministic methods and Monte Carlo method of resolution of the Boltzmann equation, methods of resolution of generalized Bateman equations, methods of time resolution of space kinetics coupled equations. It presents the main calculation codes, discusses the qualification and experimental aspects, and gives an overview of neutron transport applications: neutron transport calculation of reactors, neutron transport coupled with other disciplines, physics of fuel cycle, criticality

  10. Evaluating changes of transport properties of chemically degrading concrete using a coupled reactive transport model

    International Nuclear Information System (INIS)

    This paper presents a model to simulate chemical degradation of concrete due to leaching. The model considers simultaneously the multi-scale nature of concrete, a thermodynamic description of cement phases, and time-variable transport properties. It is implemented in the generic simulator HP1, which simulates the reactive transport in variably-saturated porous media. To illustrate the capabilities of the program, we simulate diffusive transport through concrete in contact with waters of different solution compositions (i.e., concentrations of major cations and anions and inorganic carbon contents) and use a homogenization scheme for up-scaling tortuosity. The simulations show the coupled effects between geochemical state variables, transport properties, and durability criteria for cementitious materials used in near-surface radioactive waste disposal facilities. (authors)

  11. Conversion kinetics for smelt anions: cyanate and sulfide

    Energy Technology Data Exchange (ETDEWEB)

    DeMartini, N.

    2004-07-01

    Cyanate and sulfide are two anions found in the molten salts (smelt) from the kraft recovery boiler of the chemical recovery cycle. Their concentrations in smelt are significantly different, as are their origins. The concentration of cyanate in smelt ranges between 0.4 and 2.1 g OCN{sup -}/kg smelt while the concentration of sulfide ranges between 78 and 115 g S{sup 2-}/kg smelt. Cyanate is a by-product of black liquor combustion. It is formed from organic nitrogen compounds in black liquor during the char burning stage. The charge of the cyanate anion is balanced by the alkali metals found in smelt, namely sodium and potassium. It has been found that the nitrogen in cyanate represents about 30% of the nitrogen entering the recovery boiler with the black liquor. This flow is similar in magnitude to the flows of black liquor nitrogen exiting the recovery boiler as the gaseous compounds NO and N{sub 2}. The method for cyanate analysis used in this work is presented in the Methods chapter of this thesis and Paper I. The results from nitrogen balances at three European kraft pulp mills are discussed in this thesis and Papers II and III, with a focus on the fate of cyanate in the recovery boiler and recausticizing process. Cyanate exits the recovery boiler with the smelt and reacts to form ammonia in the recausticizing solutions of the chemical recovery cycle. Papers IV and V of this thesis focus on the rate of ammonia formation from cyanate in model solutions and in kraft green liquors. The experiments were carried out at temperatures of 80 to 95 deg C, which are temperatures similar to those found in the recausticizing process of a kraft pulp mill. The kinetic studies help clarify the catalytic effect of bicarbonate. A rate equation applicable for use in describing ammonia formation from cyanate in highly alkaline solutions such as pulp mill recovery streams is presented. The sulfide anion, on the other hand, is a desired product of black liquor combustion as the

  12. Electroactive Materials for Anion Separation -- Technetium from Nitrate

    International Nuclear Information System (INIS)

    The general aim of this project is to design and prepare new electroactive ion-exchange (EaIX) materials that can be used to remove the radioactive components from high-level radioactive waste (HLW) at U.S. Department of Energy (DOE) sites nationwide. The specific objective is to develop and investigate redox-active polymers, such as polyvinylferrocene (PVF), that can be used to remove pertechnetate (TcO4-) ion from HLW. Electroactive materials are an important class of materials for this application because they can minimize or eliminate secondary waste streams associated with HLW processing, thereby reducing the costs of environmental cleanup. The technologies currently available for treatment and disposal of approximately 90 million gallons of HLW at the DOE Savannah River Site, Idaho National Engineering and Environmental Laboratory, and Hanford Site are neither cost-effective nor practical. Processes to separate the HLW constituents from the low-level waste (LLW) fraction are required to reduce the volume of waste that must be treated and disposed of and to reduce the cost of treatment and disposal. Use of EaIX materials, conjoined with the use of porous membranes that also are under development, can significantly reduce or eliminate secondary wastes associated with more traditional ion-exchange or solvent extraction technologies and, thus, can help improve the effectiveness and reduce the cost of DOE's waste treatment and disposal efforts. Beyond its importance as a cost issue, separation of TcO4- from HLW also addresses a critical environmental issue. The most common isotope of technetium (99Tc) has an extremely long half-life of 210,000 years. Rapid development of advanced methods to remove and separate this long-lived radioactive isotope is important because most of the technetium in the DOE HLW probably is in the form of TcO4-, which is highly mobile in soils and groundwater. This project is focused on anion separation and, in particular, the selective

  13. Photoelectron spectra and structure of the Mnn− anions (n = 2–16)

    International Nuclear Information System (INIS)

    Photoelectron spectra of the Mnn− anion clusters (n = 2–16) are obtained by anion photoelectron spectroscopy. The electronic and geometrical structures of the anions are computed using density functional theory with generalized gradient approximation and a basis set of triple-ζ quality. The electronic and geometrical structures of the neutral Mnn clusters have also been computed to estimate the adiabatic electron affinities. The average absolute difference between the computed and experimental vertical detachment energies of an extra electron is about 0.2 eV. Beginning with n = 6, all lowest total energy states of the Mnn− anions are ferrimagnetic with the spin multiplicities which do not exceed 8. The computed ionization energies of the neutral Mnn clusters are in good agreement with previously obtained experimental data. According to the results of our computations, the binding energies of Mn atoms are nearly independent on the cluster charge for n > 6 and possess prominent peaks at Mn13 and Mn13− in the neutral and anionic series, respectively. The density of states obtained from the results of our computations for the Mnn− anion clusters show the metallic character of the anion electronic structures

  14. Analysis of anionic post-blast residues of low explosives from soil samples of forensic interest

    International Nuclear Information System (INIS)

    The growing threats and terrorist activities in recent years have urged the need for rapid and accurate forensic investigation on post-blast samples. The analysis of explosives and their degradation products in soils are important to enable forensic scientist to identify the explosives used in the bombing and establish possible links to their likely origin. Anions of interest for post-blast identification of low explosives were detected and identified using ion chromatography (IC). IC separations of five anions (Cl-, NO2-, NO3-, SO42-, SCN-) employed a Metrosep Anion Dual 2 column with carbonate eluent. The anions were separated within 17 minutes. Sampling of post blast residues was carried out in Rompin, Pahang. The post-blast explosive residues were extracted from soil samples collected at the seat of three simulated explosion points. The homemade explosives comprised of black powder of various amounts (100 g, 150 g and 200 g) packed in small plastic sauce bottles. In black powder standard, three anions (Cl-, NO3-, SO42-) were identified. However, low amounts of nitrite (NO2-) were found present in post-blast soil samples. The amounts of anions were generally found to be decreased with decreasing amount of black powder explosive used. The anions analysis was indicative that nitrates were being used as one of the black powder explosive ingredients. (author)

  15. Polyethyleneimine as a novel desorbent for anionic organic dyes on layered double hydroxide surface.

    Science.gov (United States)

    Wang, Siming; Li, Zenghe; Lu, Chao

    2015-11-15

    Polyethyleneimine (PEI) is a positively charged polymer with hydrogen-bonding sites and hydrophobic chains. Therefore, it has been clearly established as an efficient adsorbent by means of these native properties in the literatures. However, there is apparently no good reason to disregard the use of PEI as a desired desorbent. Herein, using methyl orange as a model anionic dye, we investigated the desorption performances of PEI toward anionic dyes adsorbed on the surface of CO3-layered double hydroxides (LDHs) in a wide range of pH values. The experiment results showed that the positively charged PEI had very strong desorption capacity for anionic dyes at low pH values (9.5), PEI existed as neutral molecule, it could desorb methyl orange via hydrogen bonding between the amino groups of it and sulfonate group of methyl orange; simultaneously, the anion-exchange process occurred between abundant hydroxyl anions and anionic methyl orange. The adsorption capacity of the used LDH adsorbent was about 80% after five cycles of adsorption-desorption-regeneration, which was much higher than that conducted by 0.1M NaOH solution. These findings suggested that PEI could be regarded as a promising desorbent for enriching anionic dyes in wastewater and regenerating LDHs through surface adsorption-desorption cycles. PMID:26255712

  16. Separation of bivalent anti-T cell immunotoxin from Pichia pastoris glycoproteins by borate anion exchange.

    Science.gov (United States)

    Woo, Jung Hee; Neville, David M

    2003-08-01

    A major problem encountered in the large-scale purification of the bivalent anti-T cell immunotoxin, A-dmDT390-bisFv(G4S), from Pichia pastoris supernatants was the presence of host glycoproteins exhibiting similar charge, size, and hydrophobicity characteristics. We overcame this problem by employing borate anion exchange chromatography. The borate anion has an affinity for carbohydrates and imparts negative charges to these structures. We found that at a concentration of sodium borate between 50 and 100 mM, the nonglycosylated immunotoxin did not bind to Poros 50 HQ anion exchanger resin, but glycoproteins, including aggregates related to the immunotoxin, did. By using this property of the immunotoxin in the presence of sodium borate, we successfully developed a 3-step purification procedure: (i) Butyl-650M hydrophobic interaction chromatography, (ii) Poros 50 HQ anion exchange chromatography in the presence of borate, and (iii) HiTrap Q anion exchange chromatography. The final preparation exhibited a purity of greater than 98% and a yield of greater than 50% from the supernatant. Previously, boronic acid resins have been used to separate glycoproteins from proteins. However, combining borate anion with conventional anion exchange resins accomplishes the separation of the immunotoxin from glycoproteins and eliminates the need to evaluate nonstandard resins with respect to good manufacturing practice guidelines. PMID:12951782

  17. Role of anion polarizability in fluorescence sensitization of DNA-templated silver nanoclusters

    Science.gov (United States)

    Peng, Jian; Shao, Yong; Liu, Lingling; Zhang, Lihua; Fu, Wensheng; Liu, Hua

    2014-06-01

    Fluorescent silver nanoclusters (Ag NCs) as novel fluorophores have received much attention because of their high brightness, good photostability and widely tunable emissions from the visible to the near-infrared range as a result of their size and existing environment. However, efforts are still needed to find the factors that tune the emission of Ag NCs. In this work, Ag NCs that were size-selectively grown on DNA were used to investigate the effect of the electronic properties of coordinating ligands. Halogen anions were used as the paradigm because of their periodicity in element properties. We found that addition of halogen anions did not alter the emission wavelength of Ag NCs, but the fluorescence intensity showed an initial increase at low concentrations of Cl-, Br- and I- followed by a gradual decrease at high concentrations. No increase in fluorescence was observed for F- at either low or high concentration. Such specific halogen-anion sensitization of the fluorescence of Ag NCs suggests that the binding strength/manner and dipole polarizability of these anions synergistically tune the emission behavior of Ag NCs. Less fluorescence sensitization occurred for the anion having high enough polarizability to form a covalent bond with Ag NCs. The anion polarizability-sensitized fluorescence indicates the role of anion electronic properties in tuning the emission behavior of Ag NCs, which should be seriously considered in designing Ag NC-based sensors and devices.

  18. Low-lying electronic structure of EuH, EuOH, and EuO neutrals and anions determined by anion photoelectron spectroscopy and DFT calculations

    Energy Technology Data Exchange (ETDEWEB)

    Kafader, Jared O.; Ray, Manisha; Jarrold, Caroline Chick, E-mail: cjarrold@indiana.edu [Department of Chemistry, Indiana University, Bloomington, Indiana 47405 (United States)

    2015-07-21

    The anion photoelectron (PE) spectra of EuH{sup −} and the PE spectrum of overlapping EuOH{sup −} and EuO{sup −} anions are presented and analyzed with supporting results from density functional theory calculations on the various anions and neutrals. Results point to ionically bound, high-spin species. EuH and EuOH anions and neutrals exhibit analogous electronic structures: Transitions from {sup 8}Σ{sup −} anion ground states arising from the 4f{sup 7}σ{sub 6s}{sup 2} superconfiguration to the close-lying neutral {sup 9}Σ{sup −} and {sup 7}Σ{sup −} states arising from the 4f{sup 7}σ{sub 6s} superconfiguration are observed spaced by an energy interval similar to the free Eu{sup +} [4f{sup 7}6s] {sup 9}S - {sup 7}S splitting. The electron affinities (EAs) of EuH and EuOH are determined to be 0.771 ± 0.009 eV and 0.700 ± 0.011 eV, respectively. Analysis of spectroscopic features attributed to EuO{sup −} photodetachment is complicated by the likely presence of two energetically competitive electronic states of EuO{sup −} populating the ion beam. However, based on the calculated relative energies of the close-lying anion states arising from the 4f{sup 7}σ{sub 6s} and 4f{sup 6}σ{sub 6s}{sup 2} configurations and the relative energies of the one-electron accessible 4f{sup 7} and 4f{sup 6}σ{sub 6s} neutral states based on ligand-field theory [M. Dulick, E. Murad, and R. F. Barrow, J. Chem. Phys. 85, 385 (1986)], the remaining features are consistent with the 4f{sup 6}σ{sub 6s}{sup 2}  {sup 7}Σ{sup −} and 4f{sup 7}σ{sub 6s}{sup 7}Σ{sup −} anion states lying very close in energy (the former was calculated to be 0.15 eV lower in energy than the latter), though the true anion ground state and neutral EA could not be established unambiguously. Calculations on the various EuO anion and neutral states suggest 4f-orbital overlap with 2p orbitals in species with 4f{sup 6} occupancy.

  19. Low-lying electronic structure of EuH, EuOH, and EuO neutrals and anions determined by anion photoelectron spectroscopy and DFT calculations

    International Nuclear Information System (INIS)

    The anion photoelectron (PE) spectra of EuH− and the PE spectrum of overlapping EuOH− and EuO− anions are presented and analyzed with supporting results from density functional theory calculations on the various anions and neutrals. Results point to ionically bound, high-spin species. EuH and EuOH anions and neutrals exhibit analogous electronic structures: Transitions from 8Σ− anion ground states arising from the 4f7σ6s2 superconfiguration to the close-lying neutral 9Σ− and 7Σ− states arising from the 4f7σ6s superconfiguration are observed spaced by an energy interval similar to the free Eu+ [4f76s] 9S - 7S splitting. The electron affinities (EAs) of EuH and EuOH are determined to be 0.771 ± 0.009 eV and 0.700 ± 0.011 eV, respectively. Analysis of spectroscopic features attributed to EuO− photodetachment is complicated by the likely presence of two energetically competitive electronic states of EuO− populating the ion beam. However, based on the calculated relative energies of the close-lying anion states arising from the 4f7σ6s and 4f6σ6s2 configurations and the relative energies of the one-electron accessible 4f7 and 4f6σ6s neutral states based on ligand-field theory [M. Dulick, E. Murad, and R. F. Barrow, J. Chem. Phys. 85, 385 (1986)], the remaining features are consistent with the 4f6σ6s2  7Σ− and 4f7σ6s7Σ− anion states lying very close in energy (the former was calculated to be 0.15 eV lower in energy than the latter), though the true anion ground state and neutral EA could not be established unambiguously. Calculations on the various EuO anion and neutral states suggest 4f-orbital overlap with 2p orbitals in species with 4f6 occupancy

  20. Sodium-coupled dicarboxylate and citrate transporters from the SLC13 family

    OpenAIRE

    Pajor, AM

    2014-01-01

    The SLC13 family in humans and other mammals consists of sodium-coupled transporters for anionic substrates: three transporters for dicarboxylates/ citrate and two transporters for sulfate. This review will focus on the di- and tricarboxylate transporters: NaDC1 (SLC13A2), NaDC3 (SLC13A3), and NaCT (SLC13A5). The substrates of these transporters are metabolic intermediates of the citric acid cycle, including citrate, succinate, and α-ketoglutarate, which can exert signaling effects through sp...

  1. Theoretical investigations on the layer-anion interaction in Mg-Al layered double hydroxides: Influence of the anion nature and layer composition

    Science.gov (United States)

    Cuautli, Cristina; Ireta, Joel

    2015-03-01

    The influence of the anion nature and layer composition on the anion-layer interaction in Mg-Al layered double hydroxides (LDHs) is investigated using density functional theory. Changes in the strength of the anion-layer interaction are assessed calculating the potential energy surface (PES) associated to the interlayer anion (OH-/Cl-) in Mg-Al-OH and Mg-Al-Cl LDHs. The layer composition is varied changing the divalent to trivalent cation proportion (R). Mg-Al-OH is thus investigated with R = 2, 3, 3.5 and Mg-Al-Cl with R = 3. It is found that the PES for OH- in Mg-Al-OH/R = 3 presents wider energy basins and lower energy barriers than any other of the investigated compositions. It is shown that the latter is connected to the number of hydrogen bonds formed by the anions. These results have interesting implications for understanding the enhancement of the physicochemical properties of LDHs upon changing composition.

  2. Influence of montmorillonites exchange capacity on the basal spacing of cation–anion organo-montmorillonites

    Energy Technology Data Exchange (ETDEWEB)

    Sanqin, Wu [School of Materials Sciences and Technology, China University of Geosciences, No. 29 Xueyuan Road, Beijing, 100083 (China); Zepeng, Zhang, E-mail: unite508@163.com [School of Materials Sciences and Technology, China University of Geosciences, No. 29 Xueyuan Road, Beijing, 100083 (China); Yunhua, Wang [Zhejiang Fenghong New Material Co., Ltd. (China); Libing, Liao [School of Materials Sciences and Technology, China University of Geosciences, No. 29 Xueyuan Road, Beijing, 100083 (China); Jiansheng, Zhang [Tangshan College, Tangshan 063000 (China)

    2014-11-15

    Graphical abstract: This picture shows the distribution of organic modifier (CTAB and SDS) in Mt interlayer and the basal spacing changes of Mt modified by CTAB and SDS. Organic modifier molecule in Mt interlayer is more and more orderly. The basal spacing of Mt is from 1.5 nm to 5 nm as modifier added. - Highlights: • The d{sub 001} of Ca-Mt, R-Na-Mt, Na-Mt modified by CTAB and SDS can reach 5 nm. • It is easier to get cation–anion OMt with greater d{sub 001} if CEC is lower. • The organic molecules distribution in cation–anion OMt was analyzed. • The influence mechanism of Ca-Mt CEC on the d{sub 001} was discussed. - Abstract: With cationic and anionic surfactants cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfonate (SDS) as modifiers, Ca-montmorillonites (Ca-Mt), artificial Na-montmorillonites (R-Na-Mt) and natural Na-montmorillonites (Na-Mt) with different cation exchange capacity (CEC) were modified by solution intercalation method, respectively. Then cation–anion organo-montmorillonites (OMt) were prepared. The influence of CEC on the basal spacing of cation–anion OMt and the influence mechanism were discussed by X-ray diffraction (XRD) and zeta potential testing. The results indicate that the basal spacing of cation–anion OMt is related to CEC. For the same type montmorillonites, the basal spacing of cation–anion OMt decreases with the increase of CEC and it is easier to get cation–anion OMt with greater basal spacing when CEC is lower. Moreover, the CEC of Na-Mt has the greatest influence on the basal spacing of cation–anion OMt.

  3. Anion-π interactions in complexes of proteins and halogen-containing amino acids.

    Science.gov (United States)

    Borozan, Sunčica Z; Zlatović, Mario V; Stojanović, Srđan Đ

    2016-06-01

    We analyzed the potential influence of anion-π interactions on the stability of complexes of proteins and halogen-containing non-natural amino acids. Anion-π interactions are distance and orientation dependent and our ab initio calculations showed that their energy can be lower than -8 kcal mol(-1), while most of their interaction energies lie in the range from -1 to -4 kcal mol(-1). About 20 % of these interactions were found to be repulsive. We have observed that Tyr has the highest occurrence among the aromatic residues involved in anion-π interactions, while His made the least contribution. Furthermore, our study showed that 67 % of total interactions in the dataset are multiple anion-π interactions. Most of the amino acid residues involved in anion-π interactions tend to be buried in the solvent-excluded environment. The majority of the anion-π interacting residues are located in regions with helical secondary structure. Analysis of stabilization centers for these complexes showed that all of the six residues capable of anion-π interactions are important in locating one or more of such centers. We found that anion-π interacting residues are sometimes involved in simultaneous interactions with halogens as well. With all that in mind, we can conclude that the anion-π interactions can show significant influence on molecular organization and on the structural stability of the complexes of proteins and halogen-containing non-natural amino acids. Their influence should not be neglected in supramolecular chemistry and crystal engineering fields as well. PMID:26910415

  4. Purification of degraded TBP solvent using macroreticular anion exchange resin

    International Nuclear Information System (INIS)

    Tri-n-butyl phosphate (TBP) diluted with a suitable diluent is commonly used for solvent extraction in Purex process for the recovery of uranium and plutonium from irradiated nuclear fuels. This solvent gets degraded due to various factors, the main degradation product being dibutyl phosphoric acid (HDBP). A solvent cleanup step is generally incorporated in the process for removing the degradation products from the used solvent. A liquid-liquid cleanup system using sodium carbonate or sodium hydroxide solution is routinely used. Considering certain advantages, like the possibility of loading the resin almost to saturation capacity and the subsequent disposal of the spent resin by incineration and the feasibility of adopting it to the process, a liquid-solid system has been tried as an alternate method, employing various available macroreticular anion exchange resins in OH- form for the sorption of HDBP from TBP. After standardizing the various conditions for the satisfactory removal of HDBP from TBP using synthetic mixtures, resins were tested with process solvent in batch contacts. The parameters studied were (1) capacity of different resins for HDBP sorption (2) influence of acidity, uranium and HDBP on the sorption behaviour of the latter (3) removal of fission products from the solvent by the resin and (4) regeneration and recycling of the resin. (author). 2 figs., 13 tabs., 17 refs

  5. Anion-exchange sorption of molybdate and germanate

    Energy Technology Data Exchange (ETDEWEB)

    Kislinskaya, G.E.; Denisova, T.I.; Sheka, I.A.

    1983-07-20

    Interest in sorption of molybdenum and germanium from salt solutions is prompted by industrial requirements related to purification of such solutions and also to extraction of these elements from various industrial liquors.In order to identify the ionic forms of molybdenum and germanium having the highest sorption activity and to determine the optimal conditions for extraction of these elements from solutions with high electrolyte contents, we studied the states of molybdenum(VI) and germanium(IV) in solutions of sodium chloride in various concentrations, and sorption of these elements by strongly basic macroporous anion-exchange resins and by iron and aluminum hydroxides in relation to the pH, concentrations of the elements, and time of contact between the solution and the sorbent. Examination of literature data shows that the molecular and ionic states of these elements in the presence of high salt concentrations have been studied mainly in acidic solutions and at higher molybdenum and germanium concentrations. However, for selection of a method of removal of molybdenum and germanium from production liquors it is also necessary to have analogous information on their states when present in microconcentrations over wide ranges of pH.

  6. Anion-exchange sorption of molybdate and germanate

    International Nuclear Information System (INIS)

    Interest in sorption of molybdenum and germanium from salt solutions is prompted by industrial requirements related to purification of such solutions and also to extraction of these elements from various industrial liquors.In order to identify the ionic forms of molybdenum and germanium having the highest sorption activity and to determine the optimal conditions for extraction of these elements from solutions with high electrolyte contents, we studied the states of molybdenum(VI) and germanium(IV) in solutions of sodium chloride in various concentrations, and sorption of these elements by strongly basic macroporous anion-exchange resins and by iron and aluminum hydroxides in relation to the pH, concentrations of the elements, and time of contact between the solution and the sorbent. Examination of literature data shows that the molecular and ionic states of these elements in the presence of high salt concentrations have been studied mainly in acidic solutions and at higher molybdenum and germanium concentrations. However, for selection of a method of removal of molybdenum and germanium from production liquors it is also necessary to have analogous information on their states when present in microconcentrations over wide ranges of pH

  7. Conductance hysteresis in the voltage-dependent anion channel.

    Science.gov (United States)

    Rappaport, Shay M; Teijido, Oscar; Hoogerheide, David P; Rostovtseva, Tatiana K; Berezhkovskii, Alexander M; Bezrukov, Sergey M

    2015-09-01

    Hysteresis in the conductance of voltage-sensitive ion channels is observed when the transmembrane voltage is periodically varied with time. Although this phenomenon has been used in studies of gating of the voltage-dependent anion channel, VDAC, from the outer mitochondrial membrane for nearly four decades, full hysteresis curves have never been reported, because the focus was solely on the channel opening branches of the hysteresis loops. We studied the hysteretic response of a multichannel VDAC system to a triangular voltage ramp the frequency of which was varied over three orders of magnitude, from 0.5 mHz to 0.2 Hz. We found that in this wide frequency range the area encircled by the hysteresis curves changes by less than a factor of three, suggesting broad distribution of the characteristic times and strongly non-equilibrium behavior. At the same time, quasi-equilibrium two-state behavior is observed for hysteresis branches corresponding to VDAC opening. This enables calculation of the usual equilibrium gating parameters, gating charge and voltage of equipartitioning, which were found to be almost insensitive to the ramp frequency. To rationalize this peculiarity, we hypothesize that during voltage-induced closure and opening the system explores different regions of the complex free energy landscape, and, in the opening branch, follows quasi-equilibrium paths. PMID:26094068

  8. Studies on Anionic Surfactant Structure in the Aggregation with (Hydroxypropylcellulose

    Directory of Open Access Journals (Sweden)

    Ricardo M. de Martins

    2002-01-01

    Full Text Available Fluorescence probing, viscosity and light scattering measurements have been combined to study the aggregation of different anionic surfactants mainly in dilute solutions (0.5% w/v of (hydroxypropylcellulose (HPC MW 173,000, in moderate ionic strength (NaCl 0.1 mol.L-1. The set of surfactants includes natural cholesterol derivatives, sodium cholate (CS and sodium deoxycholate (DC, and the alkylsulphate, sodium dodecylsulphate (SDS. At 298 K the critical surfactant concentration related to aggregate/HPC formation (C1 decreases for SDS and DC whereas it increases slightly for CS. At 312 K the C1 values for CS and DC are slightly shifted toward higher values whereas it is not changed for SDS. All surfactant/HPC systems increase C1 values as the HPC concentration increases to 1.2%. Above C1 the viscosity increases for all surfactant/HPC systems but it is sharper in the increasing order CS, DC and SDS. The hydrodynamic behavior indicates that CS induces higher diffusion to HPC than SDS and DC. The aggregation in the surfactant/HPC systems is analyzed through the feature of surfactant/aggregate structure (size, charge density, etc.

  9. Removal of bromide and natural organic matter by anion exchange.

    Science.gov (United States)

    Hsu, Susan; Singer, Philip C

    2010-04-01

    Bromide removal by anion exchange was explored for various water qualities, process configurations, and resin characteristics. Simulated natural waters containing different amounts of natural organic matter (NOM), bicarbonate, chloride, and bromide were treated with a polyacrylate-based magnetic ion exchange (MIEX) resin on a batch basis to evaluate the effectiveness of the resin for removal of bromide. While bromide removal was achieved to some degree, alkalinity (bicarbonate), dissolved organic carbon (DOC), and chloride were shown to inhibit bromide removal in waters with bromide concentrations of 100 and 300 microg/L. Water was also treated using a two-stage batch MIEX process. Two-stage treatment resulted in only a slight improvement in bromide removal compared to single-stage treatment, presumably due to competition with the high concentration of chloride which is present along with bromide in natural waters. In view of the relatively poor bromide removal results for the MIEX resin, a limited set of experiments was performed using polystyrene resins. DOC and bromide removal were compared by treating model waters with MIEX and two polystyrene resins, Ionac A-641 and Amberlite IRA910. The two polystyrene resins were seen to be more effective for bromide removal, while the MIEX resin was more effective at removing DOC. PMID:20045170

  10. Electronic Structure Studies of Silicon Carbide Anionic Nanoclusters

    Science.gov (United States)

    Pradhan, Prachi

    2005-03-01

    As a continuation of our studies on the high stabilities and electronic structure properties of Si8C2 to Si14C2 clusters and Si60Cn (n=3-6) clusters,^1 we report here ab initio studies of small SimCn^- (1Gaussian03 suite of programs^2 with an all electron 6-311++G** basis set has been used. Complete geometry optimizations of different possible structures have been carried out. Carbon-rich and silicon rich species show distinctly different patterns with respect to the vertical detachment energies. For carbon-rich aggregates, the VDE's show an even odd alternation, similar to that of the carbon anions. We present results on binding energies, relative energies, fragmentation energies, vertical detachment energies, vibrational frequencies, and adiabatic electron affinities^3 for the optimized clusters. Detailed comparisons with published data in the literature will also be presented. * Work supported, in part, by the Welch Foundation, Houston, Texas (Grant No. Y-1525). ^1M. N. Huda and A. K. Ray, Phys. Rev. A (R) 69, 011201 (2004); Eur. Phys. J. D 31, 63 (2004). ^2 Gaussian03, Revision A.1, M. J. Frisch et al., Gaussian Inc., Pittsburgh, PA , 2003. ^3 P. Pradhan and A. K. Ray, J. Mol. Structure (Theochem), in press.

  11. Positive Anharmonicities: The Oxonide Anion as an Example

    Science.gov (United States)

    Lee, Timothy J.; Arnold, James O. (Technical Monitor)

    1997-01-01

    An accurate ab initio quartic force field for the ozonide anion has been determined at the singles and doubles coupled-cluster level of theory that includes a perturbational estimate of the effects of connected triple excitations, denoted CCSD(T), using the augmented valence triple-zeta correlation consistent one-particle basis set. Convergence of the harmonic frequencies with respect to the one-particle basis set has been demonstrated by computing quadratic force fields at the CCSD(T) level using augmented valence double-zeta and quadruple-zeta basis sets. Fundamental vibrational frequencies have been determined via second-order ro-vibrational perturbation theory and also using exact variational methods. Agreement is very good, and they both show that the antisymmetric O-O stretch, v 3, possesses a positive anharmonic correction (that is, the fundamental frequency is predicted to be higher in energy than the harmonic frequency). Comparison of the O_3 and O3 quartic force fields shows that the positive anharmonic correction is the result of a particularly large F3333 symmetry internal coordinate force constant. The reasonableness of this force constant has been tested by computing both F33 and F3333 at the CCSD, CCSD(T), and CASPT2 levels of theory. A discussion of known positive anharmonicities for stretching modes is presented.

  12. Gamma radiation effect on gas production in anion exchange resins

    International Nuclear Information System (INIS)

    Radiation-induced decomposition of Amberlite IRA400 anion exchange resin in hydroxide form by gamma radiolysis has been studied at various doses in different atmospheres (anaerobic, anaerobic with liquid water, and aerobic). The effect of these parameters on the degradation of ion exchange resins is rarely investigated in the literature. We focused on the radiolysis gases produced by resin degradation. When the resin was irradiated under anaerobic conditions with liquid water, the liquid phase over the resin was also analyzed to identify any possible water-soluble products released by degradation of the resin. The main products released are trimethylamine (TMA), molecular hydrogen (H2g) and carbon dioxide (CO2g). TMA and H2g are produced in all the irradiation atmospheres. However, TMA was in gaseous form under anaerobic and aerobic conditions and in aqueous form in presence of liquid water. In the latter conditions, TMAaq was associated with aqueous dimethylamine (DMAaq), monomethylamine (MMAaq) and ammonia (NH4+aq). CO2g is formed in the presence of oxygen due to oxidation of organic compounds present in the system, in particular the degradation products such as TMAg

  13. The ethylenedione anion: Elucidation of the intricate potential energy hypersurface

    International Nuclear Information System (INIS)

    Ab initio molecular orbital theory has been used to study the controversial potential energy surface of the ethylenedione anion C2O-2. Seven different basis sets, the largest being triple zeta plus two polarization functions and one set of higher angular momentum functions (TZ2Pf) in quality, were utilized in conjunction with five correlated methods, the highest-level being coupled-cluster theory including single, double, and perturbative triple excitations [CCSD(T)]. Equilibrium geometries and harmonic vibrational frequencies of the predicted 2Au trans-bent ground state are presented. The Renner--Teller potential energy surface resulting from the splitting of the doubly degenerate linear 2Πu transition state into the nondegenerate bent 2Au and linear 2Bu surfaces is also characterized by means of energy predictions for these three states. Several recent peak assignments in the experimental spectrum, as well as the isotopic shifts associated with them, are supported by theory. A correct description of the potential energy hypersurface is obtained only by application of large basis sets in conjunction with methods including high-level treatment of electron correlation effects. The TZP+/CCSD(T) methodology predicts the OCC bond angle to be 146.5 degree

  14. NITRORADICAL ANION FORMATION FROM NITROFURANTOIN IN CARBON ELECTRODES

    Directory of Open Access Journals (Sweden)

    M. MERINO

    2000-03-01

    Full Text Available The electrochemical nitroreduction of nitrofurantoin has been studiedon carbon paste and glassy carbon electrodes. We can observe a monoelectronicreversible couple ArNO2/ArNO2.- and anirreversible peak due to the further reduction of nitro radical to thehidroxilamine via three electrons. According to the experimental results, the reduction process shows atypical behavior of an EC mechanism. The k2 obtained values showed that the nitroradical anion was better stabilized on carbon paste electrodeLa formación electroquímica del nitro anión radicalde nitrofurantoína ha sido estudiada sobre electrodos de carbonovítreo y pasta de carbono. Se encontró que sobre ambos tipos de electrodos, existe un proceso monoelectrónico reversible correspondientea la cupla redox ArNO2/ArNO2.-, seguido de un pico irreversible correspodiente a la reducción víatres electrones del anión radical a la correspondiente hidroxilamina.De acuerdo a los resultados obtenidos, el proceso de reducción ocurrea través de un mecanismo EC, donde los valores de k2 encontrados, indican que el anión radical nitro es mejor estabilizadosobre electrodos de pasta de carbono

  15. Anion-exchange separations of metal ions in thiocyanate media.

    Science.gov (United States)

    Fritz, J S; Kaminski, E E

    1971-05-01

    The analytical potential of a weak-base macroreticular anion-exchange resin for the quantitative separation of metal ions in thiocyanate media is investigated and demonstrated. Distribution data are given for the sorption of some 25 metal ions from aqueous mixtures of potassium thiocyanate (1.0M or less) and 0.5M hydrochloric acid. The magnitude of the distribution data suggests many possible separations, some of which were quantitatively performed by procedures which are fast, simple and require only mild conditions. Representative separations are removal of traces of iron(III) and copper(II) from water samples prior to the determination of water hardness (calcium and magnesium), separation of nickel(II) from vanadium(IV) and the separation of thorium(IV) from titanium(IV). Some multicomponent separations are the separation of rare earths(III) and thorium(IV) from scandium(III) and the separation of rare earths(III) from iron(III) and uranium(VI). PMID:18960914

  16. Computer simulation of methanol exchange dynamics around cations and anions

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Santanu; Dang, Liem X.

    2016-03-03

    In this paper, we present the first computer simulation of methanol exchange dynamics between the first and second solvation shells around different cations and anions. After water, methanol is the most frequently used solvent for ions. Methanol has different structural and dynamical properties than water, so its ion solvation process is different. To this end, we performed molecular dynamics simulations using polarizable potential models to describe methanol-methanol and ion-methanol interactions. In particular, we computed methanol exchange rates by employing the transition state theory, the Impey-Madden-McDonald method, the reactive flux approach, and the Grote-Hynes theory. We observed that methanol exchange occurs at a nanosecond time scale for Na+ and at a picosecond time scale for other ions. We also observed a trend in which, for like charges, the exchange rate is slower for smaller ions because they are more strongly bound to methanol. This work was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. The calculations were carried out using computer resources provided by the Office of Basic Energy Sciences.

  17. Attribution of uranium ore concentrates using elemental and anionic data

    International Nuclear Information System (INIS)

    The capability to correctly identify the geological or geographical source of unknown uranium ore concentrates (UOCs) has obvious nuclear security benefits. This paper reports on a scoping study where the trace elemental and anionic compositions of 24 UOC samples, sourced mainly from mines in Australia and Canada, were examined for their ability to allow attribution of the sample to a particular geological U deposit type or to a particular geographical source. Results of statistical analysis using canonical analysis of principal coordinates (CAP) showed that samples originating from certain U ore deposit types, especially phosphorite and quartz-pebble conglomerate, contained a distinct impurity composition. Samples grouped according to their geographical region of origin appeared to contain distinctive impurities in certain cases (Elliot Lake and Bancroft, Ontario). The key impurities responsible for differentiating groups of samples from a particular geological deposit type were identified and the use of certain impurities as signatures of processing history is discussed. The methodology described in this scoping study provides a promising approach for more comprehensive databases.

  18. Inactivation of Bacillus Subtilis by Atomic Oxygen Radical Anion

    Institute of Scientific and Technical Information of China (English)

    LI Longchun; WANG Lian; YU Zhou; LV Xuanzhong; LI Quanxin

    2007-01-01

    UAtomic oxygen radical anion (O- ) is one of the most active oxygen species, and has extremely high oxidation ability toward small-molecules of hydrocarbons. However, to our knowledge, little is known about the effects of O- on cells of micro-organisms. This work showed that O- could quickly react with the Bacillus subtilis cells and seriously damage the cell walls a s well as their other contents, leading to a fast and irreversible inactivation. SEM micrographs revealed that the cell structures were dramatically destroyed by their exposure to O-. The inactivation efficiencies of B. subtilis depend on the O-- intensity, the initial population of cells and the treatment temperature, but not on the pH in the range of our investigation. For a cell concentration of 106 cfu/ml, the number of survived cells dropped from 106 cfu/ml to 103 cfu/ml after about five-minute irradiation by an O- flux in an intensity of 233 nA/cm2 under a dry argon environment (30 ℃, 1 atm, exposed size: 1.8 cm2). The inactivation mechanism of micro-organisms induced by O- is also discussed.

  19. Light-responsive viscoelastic fluids based on anionic wormlike micelles.

    Science.gov (United States)

    Lu, Yechang; Zhou, Tengfei; Fan, Qing; Dong, Jinfeng; Li, Xuefeng

    2013-12-15

    A new class of light-responsive viscoelastic fluids based on anionic wormlike micelles is reported. The key components are sodium oleate (NaOA) and a cationic azobenzene dye, 1-[2-(4-phenylazo-phenoxy)-ethyl]-3-methylimidazolium bromide (C0AZOC2IMB). These binary systems are gel-like fluids at certain concentration ratios of [C0AZOC2IMB]/[NaOA], e.g. 35/100, owing to the formation of long, entangled wormlike micelles. The viscosity of these fluids can be controlled reversibly by light due to photo isomerization between trans-C0AZOC2IMB and cis-C0AZOC2IMB. For example, the zero-shear viscosity (η0) of an originally gel-like sample is high up to ~1300 Pa s when C0AZOC2IMB is in its trans from, whereas the mixture becomes a Newtonian fluid with η0 about 0.01 Pa s after UV light irradiation. For the post-irradiated cis-C0AZOC2IMB, short cylindrical micelles form, hence accounting for the lower viscosity. Evidence for the structural transition is provided by UV-vis spectra, rheology, (1)H NMR and cryo-transmission electronic microscopy measurements. PMID:24144381

  20. Fouling mitigation of anion exchange membrane by zeta potential control.

    Science.gov (United States)

    Park, Jin-Soo; Lee, Hong-Joo; Choi, Seok-Ju; Geckeler, Kurt E; Cho, Jaeweon; Moon, Seung-Hyeon

    2003-03-15

    The feasibility of fouling mitigation of anion exchange membranes (AEMs) in the presence of humate was studied by adding three different types of water-soluble polymers, i.e., poly(acrylic acid) (PAA), poly(vinyl alcohol) (PVA), and poly(ethylene imine) (PEI), during electrodialysis (ED) desalination. Measurement of zeta potential of the humate used in this study showed highly negative potential (about -30 mV), implying that the humate had a strong fouling potential on the AEMs in ED. Of the three water-soluble polymers, PEI showed a positive zeta potential (about +14 mV) and is able to form an interpolymer complex with the humate. PAA and PVA hardly formed interpolymer complexes with humate due to electrostatic repulsion. The PEI-humate mixture with a volume ratio of 1:20 (PEI:humate) showed zero zeta potential, and a complexed humate with zero surface charge was formed, resulting in no fouling effects on the AEMs. Accordingly, the desalting ED experiments with PEI showed improved ED performance. Further, black colloids formed in the mixture did not cause the cell resistance to increase. PMID:16256509