Sample records for acid anion concentrations

  1. External concentration of organic acid anions and pH: key independent variables for studying how organic acids inhibit growth of bacteria in mildly acidic foods.

    PubMed

    Carpenter, C E; Broadbent, J R

    2009-01-01

    Although the mechanisms by which organic acids inhibit growth of bacteria in mildly acidic foods are not fully understood, it is clear that intracellular accumulation of anions is a primary contributor to inhibition of bacterial growth. We hypothesize that intracellular accumulation of anions is driven by 2 factors, external anion concentration and external acidity. This hypothesis follows from basic chemistry principles that heretofore have not been fully applied to studies in the field, and it has led us to develop a novel approach for predicting internal anion concentration by controlling the external concentration of anions and pH. This approach overcomes critical flaws in contemporary experimental design that invariably target concentration of either protonated acid or total acid in the growth media thereby leaving anion concentration to vary depending on the pK(a) of the acids involved. Failure to control external concentration of anions has undoubtedly confounded results, and it has likely led to misleading conclusions regarding the antimicrobial action of organic acids. In summary, we advocate an approach for directing internal anion levels by controlling external concentration of anions and pH because it presents an additional opportunity to study the mechanisms by which organic acids inhibit bacterial growth. Knowledge gained from such studies would have important application in the control of important foodborne pathogens such as Listeria monocytogenes, and may also facilitate efforts to promote the survival in foods or beverages of desirable probiotic bacteria.

  2. Purification Or Organic Acids Using Anion Exchange Chromatography.

    DOEpatents

    Ponnampalam; Elankovan

    2001-09-04

    Disclosed is a cost-effective method for purifying and acidifying carboxylic acids, including organic acids and amino acids. The method involves removing impurities by allowing the anionic form of the carboxylic acid to bind to an anion exchange column and washing the column. The carboxylic anion is displaced as carboxylic acid by washing the resin with a strong inorganic anion. This method is effective in removing organic carboxylic acids and amino acids from a variety of industrial sources, including fermentation broths, hydrolysates, and waste streams.

  3. Roles of Organic Acid Anion Secretion in Aluminium Tolerance of Higher Plants

    PubMed Central

    Yang, Lin-Tong; Qi, Yi-Ping; Jiang, Huan-Xin; Chen, Li-Song

    2013-01-01

    Approximately 30% of the world's total land area and over 50% of the world's potential arable lands are acidic. Furthermore, the acidity of the soils is gradually increasing as a result of the environmental problems including some farming practices and acid rain. At mildly acidic or neutral soils, aluminium(Al) occurs primarily as insoluble deposits and is essentially biologically inactive. However, in many acidic soils throughout the tropics and subtropics, Al toxicity is a major factor limiting crop productivity. The Al-induced secretion of organic acid (OA) anions, mainly citrate, oxalate, and malate, from roots is the best documented mechanism of Al tolerance in higher plants. Increasing evidence shows that the Al-induced secretion of OA anions may be related to the following several factors, including (a) anion channels or transporters, (b) internal concentrations of OA anions in plant tissues, (d) temperature, (e) root plasma membrane (PM) H+-ATPase, (f) magnesium (Mg), and (e) phosphorus (P). Genetically modified plants and cells with higher Al tolerance by overexpressing genes for the secretion and the biosynthesis of OA anions have been obtained. In addition, some aspects needed to be further studied are also discussed. PMID:23509687

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

    PubMed

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

    2015-05-01

    The application of ion chromatography with the single pump cycling-column-switching technique was described for the analysis of trace inorganic anions in weak acid salts within a single run. Due to the hydrogen ions provided by an anion suppressor electrolyzing water, weak acid anions could be transformed into weak acids, existing as molecules, after passing through the suppressor. Therefore, an anion suppressor and ion-exclusion column were adopted to achieve on-line matrix elimination of weak acid anions with high concentration for the analysis of trace inorganic anions in weak acid salts. A series of standard solutions consisting of target anions of various concentrations from 0.005 to 10 mg/L were analyzed, with correlation coefficients r ≥ 0.9990. The limits of detection were in the range of 0.67 to 1.51 μg/L, based on the signal-to-noise ratio of 3 and a 25 μL injection volume. Relative standard deviations for retention time, peak area, and peak height were all less than 2.01%. A spiking study was performed with satisfactory recoveries between 90.3 and 104.4% for all anions. The chromatographic system was successfully applied to the analysis of trace inorganic anions in five weak acid salts. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Relationships between stream acid anion-base cation chemistry and watershed soil types on the Allegheny high plateau

    Treesearch

    Gregory P. Lewis

    1999-01-01

    The leaching of calcium and magnesium from forests by atmospherically-deposited strong acid anions (sulfate and nitrate) is evidenced in some watersheds by the positive correlation in stream water between concentrations of these base cations and acid anions.

  6. Cation–Anion Interactions within the Nucleic Acid Ion Atmosphere Revealed by Ion Counting

    PubMed Central

    Gebala, Magdalena; Giambasu, George M.; Lipfert, Jan; Bisaria, Namita; Bonilla, Steve; Li, Guangchao; York, Darrin M.; Herschlag, Daniel

    2016-01-01

    The ion atmosphere is a critical structural, dynamic, and energetic component of nucleic acids that profoundly affects their interactions with proteins and ligands. Experimental methods that “count” the number of ions thermodynamically associated with the ion atmosphere allow dissection of energetic properties of the ion atmosphere, and thus provide direct comparison to theoretical results. Previous experiments have focused primarily on the cations that are attracted to nucleic acid polyanions, but have also showed that anions are excluded from the ion atmosphere. Herein, we have systematically explored the properties of anion exclusion, testing the zeroth-order model that anions of different identity are equally excluded due to electrostatic repulsion. Using a series of monovalent salts, we find, surprisingly, that the extent of anion exclusion and cation inclusion significantly depends on salt identity. The differences are prominent at higher concentrations and mirror trends in mean activity coefficients of the electrolyte solutions. Salts with lower activity coefficients exhibit greater accumulation of both cations and anions within the ion atmosphere, strongly suggesting that cation–anion correlation effects are present in the ion atmosphere and need to be accounted for to understand electrostatic interactions of nucleic acids. To test whether the effects of cation–anion correlations extend to nucleic acid kinetics and thermodynamics, we followed the folding of P4–P6, a domain of the Tetrahymena group I ribozyme, via single-molecule fluorescence resonance energy transfer in solutions with different salts. Solutions of identical concentration but lower activity gave slower and less favorable folding. Our results reveal hitherto unknown properties of the ion atmosphere and suggest possible roles of oriented ion pairs or anion-bridged cations in the ion atmosphere for electrolyte solutions of salts with reduced activity. Consideration of these new

  7. Glutamate transporter-associated anion channels adjust intracellular chloride concentrations during glial maturation.

    PubMed

    Untiet, Verena; Kovermann, Peter; Gerkau, Niklas J; Gensch, Thomas; Rose, Christine R; Fahlke, Christoph

    2017-02-01

    Astrocytic volume regulation and neurotransmitter uptake are critically dependent on the intracellular anion concentration, but little is known about the mechanisms controlling internal anion homeostasis in these cells. Here we used fluorescence lifetime imaging microscopy (FLIM) with the chloride-sensitive dye MQAE to measure intracellular chloride concentrations in murine Bergmann glial cells in acute cerebellar slices. We found Bergmann glial [Cl - ] int to be controlled by two opposing transport processes: chloride is actively accumulated by the Na + -K + -2Cl - cotransporter NKCC1, and chloride efflux through anion channels associated with excitatory amino acid transporters (EAATs) reduces [Cl - ] int to values that vary upon changes in expression levels or activity of these channels. EAATs transiently form anion-selective channels during glutamate transport, and thus represent a class of ligand-gated anion channels. Age-dependent upregulation of EAATs results in a developmental chloride switch from high internal chloride concentrations (51.6 ± 2.2 mM, mean ± 95% confidence interval) during early development to adult levels (35.3 ± 0.3 mM). Simultaneous blockade of EAAT1/GLAST and EAAT2/GLT-1 increased [Cl - ] int in adult glia to neonatal values. Moreover, EAAT activation by synaptic stimulations rapidly decreased [Cl - ] int . Other tested chloride channels or chloride transporters do not contribute to [Cl - ] int under our experimental conditions. Neither genetic removal of ClC-2 nor pharmacological block of K + -Cl - cotransporter change resting Bergmann glial [Cl - ] int in acute cerebellar slices. We conclude that EAAT anion channels play an important and unexpected role in adjusting glial intracellular anion concentration during maturation and in response to cerebellar activity. GLIA 2017;65:388-400. © 2016 Wiley Periodicals, Inc.

  8. Elution of Re-188 from W-188/Re-188 generators with salts of weak acids permits efficient concentration to low volumes using a new tandem cation/anion exchange system

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

    Guhlke, S.; Beets, A.L.; Knapp, F.F. Jr.

    1997-05-01

    Re-188, available from a W-188/Re-188 generator, is an important therapeutic radioisotope for bone pain palliation, cancer therapy and intravascular brachytherapy, etc. Because of the relatively low specific activity of reactor-produced W-188 (ORNL HFIR, 296-370 MBq mCi/mg W-186 for 2 cycles), methods of concentrating the Re-188 bolus (10-12 mL) from clinical scale (18.5-37 BGq W-188) generators (5-6 gm alumina) are thus very important. We demonstrate for the first time a new strategy of generator elution with salts of weak acids and specific perrhenate anion {open_quotes}trapping{close_quotes} with QMA anion columns. Re-188 perrhenate is efficiently eluted (65-75%) from the alumina-based generator with 0.15-0.3more » M ammonium acetate. An acetic acid solution of Re-188 perrhenic acid is obtained by subsequent on-line passage of the generator eluant through a DOWEX AG 50Wx8 (200-400 mesh, H{sup +} form) column. Since acetic acid is not ionized (< 0.001%) at this pH (< pK{sub a} = 4.76) the perrhenate anion is then specifically trapped on a QMA {open_quotes}Light{close_quotes} anion extraction column. QMA elution with 0.9% NaCl, provides Re-188 perrhenate solution in <1 mL. Concentration of 10-20 mL of Re-188 solution (> 15 BGq) in <1 mL has been demonstrated using this simple new approach, which is also effective for concentration of Tc-99m from low specific activity Mo-99 (n,y) generators. The cation/anion tandem system is inexpensive and disposable and use can be easily automated. The availability of this very simple, efficient system is important for broad use of rhenium-188.« less

  9. Effect of anions and humic acid on the performance of nanoscale zero-valent iron particles coated with polyacrylic acid.

    PubMed

    Kim, Hong-Seok; Ahn, Jun-Young; Kim, Cheolyong; Lee, Seockheon; Hwang, Inseong

    2014-10-01

    Effects of anions (NO3(-), HCO3(-), Cl(-), SO4(2-)) and humic acid on the reactivity and core/shell chemistries of polyacrylic acid-coated nanoscale zero-valent iron (PAA-NZVI) and inorganically modified NZVI (INORG-NZVI) particles were investigated. The reactivity tests under various ion concentrations (0.2-30mN) revealed the existence of a favorable molar ratio of anion/NZVI that increased the reactivity of NZVI particles. The presence of a relatively small amount of humic acid (0.5mgL(-1)) substantially decreased the INORG-NZVI reactivity by 76%, whereas the reactivity of PAA-NZVI decreased only by 12%. The XRD and TEM results supported the role of the PAA coating of PAA-NZVI in impeding the oxidation of the Fe(0) core by groundwater solutes. This protective role provided by the organic coating also resulted in a 2.3-fold increase in the trichloroethylene (TCE) reduction capacity of PAA-NZVI compared to that of INORG-NZVI in the presence of anions/humic acid. Ethylene and ethane were simultaneously produced as the major reduction products of TCE in both NZVI systems, suggesting that a hydrodechlorination occurred without the aid of metallic catalysts. The PAA coating, originally designed to improve the mobility of NZVI, enhanced TCE degradation performances of NZVI in the presence of anions and humic acid. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Enhancing Cation Diffusion and Suppressing Anion Diffusion via Lewis-Acidic Polymer Electrolytes.

    PubMed

    Savoie, Brett M; Webb, Michael A; Miller, Thomas F

    2017-02-02

    Solid polymer electrolytes (SPEs) have the potential to increase both the energy density and stability of lithium-based batteries, but low Li + conductivity remains a barrier to technological viability. SPEs are designed to maximize Li + diffusivity relative to the anion while maintaining sufficient salt solubility. It is thus remarkable that poly(ethylene oxide) (PEO), the most widely used SPE, exhibits Li + diffusivity that is an order of magnitude smaller than that of typical counterions at moderate salt concentrations. We show that Lewis-basic polymers like PEO favor slow cation and rapid anion diffusion, while this relationship can be reversed in Lewis-acidic polymers. Using molecular dynamics, polyboranes are identified that achieve up to 10-fold increases in Li + diffusivities and significant decreases in anion diffusivities, relative to PEO in the dilute-ion regime. These results illustrate a general principle for increasing Li + diffusivity and transference number with chemistries that exhibit weaker cation and stronger anion coordination.

  11. Amino acid analysis in mammalian cell culture media containing serum and high glucose concentrations by anion exchange chromatography and integrated pulsed amperometric detection.

    PubMed

    Genzel, Yvonne; König, Susanne; Reichl, Udo

    2004-12-01

    The direct separation detection of amino acids by anion exchange chromatography with integrated pulsed amperometric detection was optimized for the analysis of typical mammalian cell culture broth samples. Existing gradient elution conditions were adapted, considering the additions of peptone (2 g/L) and 10 vol% fetal calf serum to the medium as well as changing concentrations of glucose from 5.5 g/L up to complete consumption. Samples had to be analyzed in two dilutions with water (1:33.3 and 1:200) due to the strongly varying amino acid concentrations in the samples as a result of the medium composition and cell metabolism. The method was validated in a linear working range for the most common amino acids (2.5-7.5 and 1.25-3.75 microM for cystine/cysteine with 15 microl injection volume). The relative standard deviation of the method for all amino acids was less than 5%, with detection limits of less than 0.6 microM and quantitation limits of less than 1.6 microM. As an example, data for the amino acid composition of different media used for the production of inactivated influenza vaccines in cell culture are shown.

  12. Freezing-Enhanced Dissolution of Iron Oxides: Effects of Inorganic Acid Anions.

    PubMed

    Jeong, Daun; Kim, Kitae; Min, Dae Wi; Choi, Wonyong

    2015-11-03

    Dissolution of iron from mineral dust particles greatly depends upon the type and amount of copresent inorganic anions. In this study, we investigated the roles of sulfate, chloride, nitrate, and perchlorate on the dissolution of maghemite and lepidocrocite in ice under both dark and UV irradiation and compared the results with those of their aqueous counterparts. After 96 h of reaction, the total dissolved iron in ice (pH 3 before freezing) was higher than that in the aqueous phase (pH 3) by 6-28 times and 10-20 times under dark and UV irradiation, respectively. Sulfuric acid was the most efficient in producing labile iron under dark condition, whereas hydrochloric acid induced the most dissolution of the total and ferrous iron in the presence of light. This ice-induced dissolution result was also confirmed with Arizona Test Dust (AZTD). In the freeze-thaw cycling test, the iron oxide samples containing chloride, nitrate, or perchlorate showed a similar extent of total dissolved iron after each cycling while the sulfate-containing sample rapidly lost its dissolution activity with repeating the cycle. This unique phenomenon observed in ice might be related to the freeze concentration of protons, iron oxides, and inorganic anions in the liquid-like ice grain boundary region. These results suggest that the ice-enhanced dissolution of iron oxides can be a potential source of bioavailable iron, and the acid anions critically influence this process.

  13. Temporary anion states of selected amino acids

    NASA Astrophysics Data System (ADS)

    Aflatooni, K.; Hitt, B.; Gallup, G. A.; Burrow, P. D.

    2001-10-01

    Vertical attachment energies for the formation of low-lying temporary anion states of glycine, alanine, phenylalanine, tryptophan, and proline in the gas phase are reported using electron transmission spectroscopy. Electron attachment into the empty π* orbital of the -COOH group was observed in all the compounds. Temporary anion states associated with the side groups in phenylalanine and tryptophan are found to be stabilized with respect to those in the reference compounds toluene and indole, respectively, by approximately 0.2 eV. We attribute this to electrostatic effects and explore, using simple theoretical models, the extent to which such anion states could be further stabilized if these amino acids were in zwitterionic form.

  14. The serum anion gap in the evaluation of acid-base disorders: what are its limitations and can its effectiveness be improved?

    PubMed

    Kraut, Jeffrey A; Nagami, Glenn T

    2013-11-01

    The serum anion gap has been utilized to identify errors in the measurement of electrolytes, to detect paraproteins, and, most relevant to the nephrologist, to evaluate patients with suspected acid-base disorders. In regard to the latter purpose, traditionally an increased anion gap is identified when it exceeds the upper limit of normal for a particular clinical laboratory measurement. However, because there is a wide range of normal values (often 8-10 mEq/L), an increase in anion concentration can be present in the absence of an increased anion gap. In addition, the type of retained anion can affect the magnitude of the increase in anion gap relative to change in serum [HCO3(-)] being greater with lactic acidosis compared with ketoacidosis. This review examines the methods of calculation of the serum anion gap in textbooks and published literature, the effect of perturbations other than changes in acid-base balance, and its effectiveness in identifying mild and more severe disturbances in acid-base balance. Limitations of the present methods of determining the normal anion gap and change in the anion gap are highlighted. The possibility of identifying the baseline value for individuals to optimize the use of the calculation in the detection of metabolic acidosis is suggested.

  15. The Serum Anion Gap in the Evaluation of Acid-Base Disorders: What Are Its Limitations and Can Its Effectiveness Be Improved?

    PubMed Central

    Nagami, Glenn T.

    2013-01-01

    Summary The serum anion gap has been utilized to identify errors in the measurement of electrolytes, to detect paraproteins, and, most relevant to the nephrologist, to evaluate patients with suspected acid-base disorders. In regard to the latter purpose, traditionally an increased anion gap is identified when it exceeds the upper limit of normal for a particular clinical laboratory measurement. However, because there is a wide range of normal values (often 8–10 mEq/L), an increase in anion concentration can be present in the absence of an increased anion gap. In addition, the type of retained anion can affect the magnitude of the increase in anion gap relative to change in serum [HCO3−] being greater with lactic acidosis compared with ketoacidosis. This review examines the methods of calculation of the serum anion gap in textbooks and published literature, the effect of perturbations other than changes in acid-base balance, and its effectiveness in identifying mild and more severe disturbances in acid-base balance. Limitations of the present methods of determining the normal anion gap and change in the anion gap are highlighted. The possibility of identifying the baseline value for individuals to optimize the use of the calculation in the detection of metabolic acidosis is suggested. PMID:23833313

  16. Recurrent high anion gap metabolic acidosis secondary to 5-oxoproline (pyroglutamic acid).

    PubMed

    Tailor, Prayus; Raman, Tuhina; Garganta, Cheryl L; Njalsson, Runa; Carlsson, Katarina; Ristoff, Ellinor; Carey, Hugh B

    2005-07-01

    High anion gap metabolic acidosis in adults is a severe metabolic disorder for which the primary organic acid usually is apparent by clinical history and standard laboratory testing. We report a case of recurrent high anion gap metabolic acidosis in a 48-year-old man who initially presented with anorexia and malaise. Physical examination was unrevealing. Arterial pH was 6.98, P co 2 was 5 mm Hg, and chemistry tests showed a bicarbonate level of 3 mEq/L (3 mmol/L), anion gap of 32 mEq/L (32 mmol/L), and a negative toxicology screen result, except for an acetaminophen (paracetamol) level of 7.5 mug/mL. Metabolic acidosis resolved with administration of intravenous fluids. Subsequently, he experienced 5 more episodes of high anion gap metabolic acidosis during an 8-month span. Methanol, ethylene glycol, acetone, ethanol, d -lactate, and hippuric acid screens were negative. Lactate levels were modestly elevated, and acetaminophen levels were elevated for 5 of 6 admissions. These episodes defied explanation until 3 urinary organic acid screens, obtained on separate admissions, showed striking elevations of 5-oxoproline levels. Inborn errors of metabolism in the gamma-glutamyl cycle causing recurrent 5-oxoprolinuria and high anion gap metabolic acidosis are rare, but well described in children. Recently, there have been several reports of apparent acquired 5-oxoprolinuria and high anion gap metabolic acidosis in adults in association with acetaminophen use. Acetaminophen may, in susceptible individuals, disrupt regulation of the gamma-glutamyl cycle and result in excessive 5-oxoproline production. Suspicion for 5-oxoproline-associated high anion gap metabolic acidosis should be entertained when the cause of high anion gap metabolic acidosis remains poorly defined, the anion gap cannot be explained reasonably by measured organic acids, and there is concomitant acetaminophen use.

  17. Retention of metal and sulphate ions from acidic mining water by anionic nanofibrillated cellulose.

    PubMed

    Venäläinen, Salla H; Hartikainen, Helinä

    2017-12-01

    We carried out an adsorption experiment to investigate the ability of anionic nanofibrillated cellulose (NFC) to retain metal and SO 4 2- ions from authentic highly acidic (pH3.2) mining water. Anionic NFC gels of different consistencies (1.1-%, 1.4-% and 1.8-% w/w) were allowed to react for 10min with mining water, after which NFC-induced changes in the metal and SO 4 2- concentrations of the mining water were determined. The sorption capacities of the NFC gels were calculated as the difference between the element concentrations in the untreated and NFC-treated mining water samples. All the NFCs efficiently co-adsorbed both metals and SO 4 2- . The retention of metals was concluded to take place through formation of metal-ligand complexes. The reaction between the NFC ligand and the polyvalent cations renders the cellulose nanofibrils positively charged and, thus, able to retain SO 4 2- electrostatically. Adsorption capacity of the NFC gels substantially increased upon decreasing DM content as a result of the dilution-induced weakening of the mutual interactions between individual cellulose nanofibrils. This outcome reveals that the dilution of the NFC gel not only increases its purification capacity but also reduces the demand for cellulosic raw material. These results suggest that anionic NFC made of renewable materials serves as an environmentally sound and multifunctional purification agent for acidic multimetal mining waters or AMDs of high ionic strength. Unlike industrial minerals traditionally used to precipitate valuable metals from acidic mining effluents before their permanent disposal from the material cycle, NFC neither requires mining of unrenewable raw materials nor produces inorganic sludges. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Boric acid increases the expression levels of human anion exchanger genes SLC4A2 and SLC4A3.

    PubMed

    Akbas, F; Aydin, Z

    2012-04-03

    Boron is an important micronutrient in plants and animals. The role of boron in living systems includes coordinated regulation of gene expression, growth and proliferation of higher plants and animals. There are several well-defined genes associated with boron transportation and tolerance in plants and these genes show close homology with human anion exchanger genes. Mutation of these genes also characterizes some genetic disorders. We investigated the toxic effects of boric acid on HEK293 cells and mRNA expression of anion exchanger (SLC4A1, SLC4A2 and SLC4A3) genes. Cytotoxicity of boric acid at different concentrations was tested by using the methylthiazolyldiphenyl-tetrazolium bromide assay. Gene expression profiles were examined using quantitative real-time PCR. In the HEK293 cells, the nontoxic upper concentration of boric acid was 250 μM; more than 500 μM caused cytotoxicity. The 250 μM boric acid concentration increased gene expression level of SLC4A2 up to 8.6-fold and SLC4A3 up to 2.6-fold, after 36-h incubation. There was no significant effect of boric acid on SLC4A1 mRNA expression levels.

  19. Concentration sensor based on a tilted fiber Bragg grating for anions monitoring

    NASA Astrophysics Data System (ADS)

    Melo, L. B.; Rodrigues, J. M. M.; Farinha, A. S. F.; Marques, C. A.; Bilro, L.; Alberto, N.; Tomé, J. P. C.; Nogueira, R. N.

    2014-08-01

    The ubiquity and importance of anions in many crucial roles accounts for the current high interest in the design and preparation of effective sensors for these species. Therefore, a tilted fiber Bragg grating sensor was fabricated to investigate individual detection of different anion concentrations in ethyl acetate, namely acetate, fluoride and chloride. The influence of the refractive index on the transmission spectrum of a tilted fiber Bragg grating was determined by developing a new demodulation method. This is based on the calculation of the standard deviation between the cladding modes of the transmission spectrum and its smoothing function. The standard deviation method was used to monitor concentrations of different anions. The sensor resolution obtained for the anion acetate, fluoride and chloride is 79 × 10-5 mol/dm3, 119 × 10-5 mol/dm3 and 78 × 10-5 mol/dm3, respectively, within the concentration range of (39-396) × 10-5 mol/dm3.

  20. Capturing and concentrating adenovirus using magnetic anionic nanobeads

    PubMed Central

    Sakudo, Akikazu; Baba, Koichi; Ikuta, Kazuyoshi

    2016-01-01

    We recently demonstrated how various enveloped viruses can be efficiently concentrated using magnetic beads coated with an anionic polymer, poly(methyl vinyl ether-maleic anhydrate). However, the exact mechanism of interaction between the virus particles and anionic beads remains unclear. To further investigate whether these magnetic anionic beads specifically bind to the viral envelope, we examined their potential interaction with a nonenveloped virus (adenovirus). The beads were incubated with either adenovirus-infected cell culture medium or nasal aspirates from adenovirus-infected individuals and then separated from the supernatant by applying a magnetic field. After thoroughly washing the beads, adsorption of adenovirus was confirmed by a variety of techniques, including immunochromatography, polymerase chain reaction, Western blotting, and cell culture infection assays. These detection methods positively identified the hexon and penton capsid proteins of adenovirus along with the viral genome on the magnetic beads. Furthermore, various types of adenovirus including Types 5, 6, 11, 19, and 41 were captured using the magnetic bead procedure. Our bead capture method was also found to increase the sensitivity of viral detection. Adenovirus below the detectable limit for immunochromatography was efficiently concentrated using the magnetic bead procedure, allowing the virus to be successfully detected using this methodology. Moreover, these findings clearly demonstrate that a viral envelope is not required for binding to the anionic magnetic beads. Taken together, our results show that this capture procedure increases the sensitivity of detection of adenovirus and would, therefore, be a valuable tool for analyzing both clinical and experimental samples. PMID:27274228

  1. Generation of aliphatic acid anions and carbon dioxide by hydrous pyrolysis of crude oils

    USGS Publications Warehouse

    Kharaka, Y.K.; Lundegard, P.D.; Ambats, G.; Evans, William C.; Bischoff, J.L.

    1993-01-01

    Two crude oils with relatively high (0.60 wt%) and low (0.18 wt%) oxygen contents were heated in the presence of water in gold-plated reactors at 300??C for 2348 h. The high-oxygen oil was also heated at 200??C for 5711 h. The compositions of aqueous organic acid anions of the oils and of the headspace gases were monitored inn order to investigate the distribution of organic acids that can be generated from liquid petroleum. The oil with higher oxygen content generated about five times as much organic anions as the other oil. The dominant organic anions produced were acetate, propionate and butyrate. Small amounts of formate, succinate, methyl succinate and oxalate were also produced. The dominant oxygen-containing product was CO2, as has been observed in similar studies on the hydrous pyrolysis of kerogen. These results indicate that a significant portion (10-30%) of organic acid anions reported i be generated by thermal alteration of oils in reservoir rocks. The bulk of organic acid anions present in formation waters, however, is most likely generated by thermal alteration of kerogen in source rocks. Kerogen is more abundant than oil in sedimentary basins and the relative yields of organic acid anions reported from the hydrous pyrolysis of kerogen are much higher than the yields obtained for the two oils. ?? 1993.

  2. Acid generation mechanism in anion-bound chemically amplified resists used for extreme ultraviolet lithography

    NASA Astrophysics Data System (ADS)

    Komuro, Yoshitaka; Yamamoto, Hiroki; Kobayashi, Kazuo; Ohomori, Katsumi; Kozawa, Takahiro

    2015-03-01

    Extreme ultraviolet (EUV) lithography is the most promising candidate for the high-volume production of semiconductor devices with half-pitches of sub 10nm. An anion-bound polymer(ABP), in which at the anion part of onium salts is polymerized, has attracted much attention from the viewpoint of the control of acid diffusion. In this study, the acid generation mechanism in ABP films was investigated using γ and EUV radiolysis. On the basis of experimental results, the acid generation mechanism in anion-bound chemically amplified resists was proposed. The protons of acids are considered to be mainly generated through the reaction of phenyl radicals with diphenylsulfide radical cations that are produced through the hole transfer to the decomposition products of onium salts.

  3. Contamination of commercial cane sugars by some organic acids and some inorganic anions.

    PubMed

    Wojtczak, Maciej; Antczak, Aneta; Lisik, Krystyna

    2013-01-01

    The aim of the paper was the identification and the quantitative evaluation of the following inorganic anions: chloride, phosphate, nitrate, nitrite, sulphate and the following organic acids: lactic, acetic, formic, malic and citric in commercial "unrefined" brown cane sugars and in cane raw sugars. The determination was carried out by high performance anion exchange chromatography with conductivity detector HPAEC-CD. The conducted analyses have shown that the content of some inorganic anions and organic acids in cane sugars may be an important criterion of the quality of commercial "unrefined" brown cane sugars. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Effect of dietary potassium and anionic salts on acid-base and mineral status in periparturient cows.

    PubMed

    Rérat, M; Schlegel, P

    2014-06-01

    Dry cow diets based on grassland forage from intensive production contain high amounts of K and could be responsible for a reduced ability to maintain Ca homoeostasis. The aim of this study was to determine whether a moderate anionic salt supplementation to a forage-based pre-calving diet with varying native K content affects the mineral and acid-base status in transition cows. Twenty-four dry and pregnant Holstein cows, without antecedent episodes of clinical hypocalcemia, were assigned to two diets during the last 4 weeks before estimated calving date. Twelve cows were fed a hay-based diet low in K (18 g K/kg DM), and 12, a hay-based diet high in K (35 g K/kg DM). Within each diet, six cows received anionic salts during the last 2 weeks before the estimated calving day. After calving, all cows received the high K diet ad libitum. Blood samples were taken daily from day 11 pre-partum to day 5 post-partum. Urine samples were taken on days 7 and 2 pre-partum and on day 2 post-partum. The anionic salt did not alter feed intake during the pre-partum period. Serum Ca was not influenced by the dietary treatments. Feeding pre-partum diets with low K concentrations induced a reduced metabolic alkalotic charge, as indicated by reduced pre-partum urinary base-acid quotient. Transition cows fed the low K diet including anionic salts induced a mild metabolic acidosis before calving, as indicated by higher urinary Ca, lower urinary pH and net acid-base excretion. Although serum Ca during the post-partum period was not affected by dietary treatment, feeding a low K diet moderately supplemented with anionic salts to reach a dietary cation-anion difference close to zero permitted to obtain a metabolic response in periparturient cows without altering the dry matter intake. Journal of Animal Physiology and Animal Nutrition © 2013 Blackwell Verlag GmbH.

  5. Weak acid-concentration Atot and dissociation constant Ka of plasma proteins in racehorses.

    PubMed

    Stampfli, H R; Misiaszek, S; Lumsden, J H; Carlson, G P; Heigenhauser, G J

    1999-07-01

    The plasma proteins are a significant contributor to the total weak acid concentration as a net anionic charge. Due to potential species difference, species-specific values must be confirmed for the weak acid anionic concentrations of proteins (Atot) and the effective dissociation constant for plasma weak acids (Ka). We studied the net anion load Atot of equine plasma protein in 10 clinically healthy mature Standardbred horses. A multi-step titration procedure, using a tonometer covering a titration range of PCO2 from 25 to 145 mmHg at 37 degrees C, was applied on the plasma of these 10 horses. Blood gases (pH, PCO2) and electrolytes required to calculate the strong ion difference ([SID] = [(Na(+) + K(+) + Ca(2+) + Mg(2+))-(Cl(-) + Lac(-) + PO4(2-))]) were simultaneously measured over a physiological pH range from 6.90-7.55. A nonlinear regression iteration to determine Atot and Ka was performed using polygonal regression curve fitting applied to the electrical neutrality equation of the physico-chemical system. The average anion-load Atot for plasma protein of 10 Standardbred horses was 14.89 +/- 0.8 mEq/l plasma and Ka was 2.11 +/- 0.50 x 10(-7) Eq/l (pKa = 6.67). The derived conversion factor (iterated Atot concentration/average plasma protein concentration) for calculation of Atot in plasma is 0.21 mEq/g protein (protein-unit: g/l). This value compares closely with the 0.24 mEq/g protein determined by titration of Van Slyke et al. (1928) and 0.22 mEq/g protein recently published by Constable (1997) for horse plasma. The Ka value compares closely with the value experimentally determined by Constable in 1997 (2.22 x 10(7) Eq/l). Linear regression of a set of experimental data from 5 Thoroughbred horses on a treadmill exercise test, showed excellent correlation with the regression lines not different from identity for the calculated and measured variables pH, HCO3 and SID. Knowledge of Atot and Ka for the horse is useful especially in exercise studies and in

  6. Influence of acidic eluent for retention behaviors of common anions and cations by ion-exclusion/cation-exchange chromatography on a weakly acidic cation-exchange resin in the H+ -form.

    PubMed

    Mori, Masanobu; Tanaka, Kazuhiko; Satori, Tatsuya; Ikedo, Mikaru; Hu, Wenzhi; Itabashi, Hideyuki

    2006-06-16

    Influence of acidic eluent on retention behaviors of common anions and cations by ion-exclusion/cation-exchange chromatography (ion-exclusion/CEC) were investigated on a weakly acidic cation-exchange resin in the H(+)-form with conductivity. Sensitivities of analyte ions, especially weak acid anions (F(-) and HCOO(-)), were affected with degree of background conductivity level with pK(a1) (first dissociation constant) of acid in eluent. The retention behaviors of anions and cations were related to that of elution dip induced after eluting acid to separation column and injecting analyte sample. These results were largely dependent on the natures of acid as eluent. Through this study, succinic acid as the eluent was suitable for simultaneous separation of strong acid anions (SO(4)(2-), Cl(-), NO(3)(-) and I(-)), weak acid anions (F(-), HCOO(-) and CH(3)COO(-)), and cations (Na(+), K(+), NH(4)(+), Mg(2+) and Ca(2+)). The separation was achieved in 20 min under the optimum eluent condition, 20 mM succinic acid/2 mM 18-crown-6. Detection limits at S/N=3 ranged from 0.10 to 0.51 microM for strong acid anions, 0.20 to 5.04 microM for weak acid anions and 0.75 to 1.72 microM for cations. The relative standard deviations of peak areas in the repeated chromatographic runs (n=10) were in the range of 1.1-2.9% for anions and 1.8-4.5% for cations. This method was successfully applied to hot spring water containing strong acid anions, weak acid anions and cations, with satisfactory results.

  7. Acid generation mechanism in anion-bound chemically amplified resists used for extreme ultraviolet lithography

    NASA Astrophysics Data System (ADS)

    Komuro, Yoshitaka; Yamamoto, Hiroki; Kobayashi, Kazuo; Utsumi, Yoshiyuki; Ohomori, Katsumi; Kozawa, Takahiro

    2014-11-01

    Extreme ultraviolet (EUV) lithography is the most promising candidate for the high-volume production of semiconductor devices with half-pitches of sub-10 nm. An anion-bound polymer (ABP), in which the anion part of onium salts is polymerized, has attracted much attention from the viewpoint of the control of acid diffusion. In this study, the acid generation mechanism in ABP films was investigated using electron (pulse), γ, and EUV radiolyses. On the basis of experimental results, the acid generation mechanism in anion-bound chemically amplified resists was proposed. The major path for proton generation in the absence of effective proton sources is considered to be the reaction of phenyl radicals with diphenylsulfide radical cations that are produced through hole transfer to the decomposition products of onium salts.

  8. Simultaneous determination of gallic acid and gentisic acid in organic anion transporter expressing cells by liquid chromatography-tandem mass spectrometry.

    PubMed

    Wang, Li; Halquist, Matthew S; Sweet, Douglas H

    2013-10-15

    In order to elucidate the role of organic anion transporters (OATs) in the renal elimination of gallic acid and gentisic acid, a new, rapid, and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the simultaneous determination of gallic acid and gentisic acid in cell lysate, using Danshensu as the internal standard (IS). After a simple liquid-liquid extraction, the analytes were detected in negative ESI mode using selected reaction monitoring. The precursor-to-product ion transitions (m/z) were 169.0→125.0, 153.1→108.0, and 196.8→135.2 for gallic acid, gentisic acid, and the IS, respectively. Chromatographic separation was achieved on a C18 column using mobile phases consisting of water with 0.1% acetic acid (A) and acetonitrile with 0.05% formic acid. (B) The total run time was 3min and calibration curves were linear over the concentrations of 0.33-2400ng/mL for both compounds (r(2)>0.995). Good precision (between 3.11% and 14.1% RSD) and accuracy (between -12.7% and 11% bias) was observed for quality controls at concentrations of 0.33 (lower limit of quantification), 1, 50, and 2000ng/mL. The mean extraction recovery of gallic acid and gentisic acid was 80.7% and 83.5%, respectively. Results from post-column infusion and post-extraction methods indicated that the analytical method exhibited negligible matrix effects. Finally, this validated assay was successfully applied in a cellular uptake study to determine the intracellular concentrations of gallic acid and gentisic acid in OAT expressing cells. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Selection of anion exchangers for detoxification of dilute-acid hydrolysates from spruce.

    PubMed

    Horváth, Ilona Sárvári; Sjöde, Anders; Nilvebrant, Nils-Olof; Zagorodni, Andrei; Jönsson, Leif J

    2004-01-01

    Six anion-exchange resins with different properties were compared with respect to detoxification of a dilute-acid hydrolysate of spruce prior to ethanolic fermentation with Saccharomyces cerevisiae. The six resins encompassed strong and weak functional groups as well as styrene-, phenol-, and acrylic-based matrices. In an analytical experimental series, fractions from columns packed with the different resins were analyzed regarding pH, glucose, furfural, hydroxymethylfurfural, phenolic compounds, levulinic acid, acetic acid, formic acid, and sulfate. An initial adsorption of glucose occurred in the strong alkaline environment and led to glucose accumulation at a later stage. Acetic and levulinic acid passed through the column before formic acid, whereas sulfate had the strongest affinity. In a preparative experimental series, one fraction from each of six columns packed with the different resins was collected for assay of the fermentability and analysis of glucose, mannose, and fermentation inhibitors. The fractions collected from strong anion-exchange resins with styrene-based matrices displayed the best fermentability: a sevenfold enhancement of ethanol productivity compared with untreated hydrolysate. Fractions from a strong anion exchanger with acrylic-based matrix and a weak exchanger with phenol-based resin displayed an intermediate improvement in fermentability, a four- to fivefold increase in ethanol productivity. The fractions from two weak exchangers with styrene- and acrylic-based matrices displayed a twofold increase in ethanol productivity. Phenolic compounds were more efficiently removed by resins with styrene- and phenol-based matrices than by resins with acrylic-based matrices.

  10. Methods development for separation of inorganic anions, organic acids and bases, and neutral organic compounds by ion chromatography and capillary electrophoresis

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

    Li, Jie

    1999-04-01

    A novel anion-exchange resin containing three amine groups was prepared by reaction of a chloromethylated polystyrene-divinylbenzene (PS-DVB) resin with diethylenetriamine. After being protonated by contact with an aqueous acid, this resin can be used for ion chromatographic separation of anions. The charge on the resins can be varied from +1 to +3 by changing the mobile phase pH. The selectivity of the new ion exchangers for various inorganic anions was quite different from that of conventional anion exchangers. The performance of this new anion exchanger was studied by changing the pH and the concentration of the eluent, and several differentmore » eluents were used with some common anions as testing analytes. Conductivity detection and UV-visible detection were applied to detect the anions after separation. The new resin can also be used for HPLC separation of neutral organic compounds. Alkylphenols and alkylbenzenes were separated with this new polymeric resin, and excellent separations were obtained under simple conditions. This report contains Chapter 1: General introduction and Chapter 6: General conclusions.« less

  11. Aromatic aldehyde-catalyzed gas-phase decarboxylation of amino acid anion via imine intermediate: An experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Xiang, Zhang

    2013-10-01

    It is generally appreciated that carbonyl compound can promote the decarboxylation of the amino acid. In this paper, we have performed the experimental and theoretical investigation into the gas-phase decarboxylation of the amino acid anion catalyzed by the aromatic aldehyde via the imine intermediate on the basis of the tandem mass spectrometry (MS/MS) technique and density functional theory (DFT) calculation. The results show that the aromatic aldehyde can achieve a remarkable catalytic effect. Moreover, the catalytic mechanism varies according to the type of amino acid: (i) The decarboxylation of α-amino acid anion is determined by the direct dissociation of the Csbnd C bond adjacent to the carboxylate, for the resulting carbanion can be well stabilized by the conjugation between α-carbon, Cdbnd N bond and benzene ring. (ii) The decarboxylation of non-α-amino acid anion proceeds via a SN2-like transition state, in which the dissociation of the Csbnd C bond adjacent to the carboxylate and attacking of the resulting carbanion to the Cdbnd N bond or benzene ring take place at the same time. Specifically, for β-alanine, the resulting carbanion preferentially attacks the benzene ring leading to the benzene anion, because attacking the Cdbnd N bond in the decarboxylation can produce the unstable three or four-membered ring anion. For the other non-α-amino acid anion, the Cdbnd N bond preferentially participates in the decarboxylation, which leads to the pediocratic nitrogen anion.

  12. ANION EXCHANGE METHOD FOR SEPARATION OF METAL VALUES

    DOEpatents

    Hyde, E.K.; Raby, B.A.

    1959-02-10

    A method is described for selectively separating radium, bismuth, poloniums and lead values from a metallic mixture of thc same. The mixture is dissolved in aqueous hydrochloric acid and the acidity is adjusted to between 1 to 2M in hydrochloric acid to form the anionic polychloro complexes of polonium and bismuth. The solution is contacted with a first anion exchange resin such as strong base quaternary ammonia type to selectively absorb the polonium and bismuth leaving the radium and lead in the effluent. The effluent, after treatment in hydrochloric acid to increase the hydrochloric acid concentration to 6M is contacted with a second anion exchange iesin of the same type as the above to selectively adsorb the lead leaving the radium in the effluent. Radium is separately recovered from the effluent from the second exchange column. Lead is stripped from the loaded resin of the second column by treatment with 3M hydrochloric acid solution. The loaded resin of the first column is washed with 8M hydrochloric acid solution to recover bismuth and then treated with strong nitric acid solution to recover polonium.

  13. Quantification of urinary zwitterionic organic acids using weak-anion exchange chromatography with tandem MS detection.

    PubMed

    Bishop, Michael Jason; Crow, Brian S; Kovalcik, Kasey D; George, Joe; Bralley, James A

    2007-04-01

    A rapid and accurate quantitative method was developed and validated for the analysis of four urinary organic acids with nitrogen containing functional groups, formiminoglutamic acid (FIGLU), pyroglutamic acid (PYRGLU), 5-hydroxyindoleacetic acid (5-HIAA), and 2-methylhippuric acid (2-METHIP) by liquid chromatography tandem mass spectrometry (LC/MS/MS). The chromatography was developed using a weak anion-exchange amino column that provided mixed-mode retention of the analytes. The elution gradient relied on changes in mobile phase pH over a concave gradient, without the use of counter-ions or concentrated salt buffers. A simple sample preparation was used, only requiring the dilution of urine prior to instrumental analysis. The method was validated based on linearity (r2>or=0.995), accuracy (85-115%), precision (C.V.<12%), sample preparation stability (acids.

  14. Photophysics and Photochemistry of 2-Aminobenzoic Acid Anion in Aqueous Solution

    NASA Astrophysics Data System (ADS)

    Pozdnyakov, Ivan P.; Plyusnin, Victor F.; Grivin, Vjacheslav P.

    2009-11-01

    Nanosecond laser flash photolysis and absorption and fluorescence spectroscopy were used to study photochemical processes of 2-aminobenzoic acid anion (ABA-) in aqueous solutions. Excitation of this species gives rise to the ABA- triplet state to the ABA• radical and to the hydrated electron (eaq-). The last two species result from two-photon processes. In a neutral medium, the main decay channels of ABA- triplet state, the ABA• radical, and eaq- are T-T annihilation, recombination, and capture by the ABA- anion, respectively.

  15. 8. VIEW OF GLOVE BOXES USED IN THE ANION EXCHANGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. VIEW OF GLOVE BOXES USED IN THE ANION EXCHANGE PROCESS. THE ANION EXCHANGE PROCESS PURIFIED AND CONCENTRATED PLUTONIUM-BEARING NITRIC ACID SOLUTIONS TO MAKE THEM ACCEPTABLE AS FEED FOR CONVERSION TO METAL. (6/20/60) - Rocky Flats Plant, Plutonium Recovery & Fabrication Facility, North-central section of plant, Golden, Jefferson County, CO

  16. Anion dependent ion pairing in concentrated ytterbium halide solutions

    NASA Astrophysics Data System (ADS)

    Klinkhammer, Christina; Böhm, Fabian; Sharma, Vinay; Schwaab, Gerhard; Seitz, Michael; Havenith, Martina

    2018-06-01

    We have studied ion pairing of ytterbium halide solutions. THz spectra (30-400 cm-1) of aqueous YbCl3 and YbBr3 solutions reveal fundamental differences in the hydration structures of YbCl3 and YbBr3 at high salt concentrations: While for YbBr3 no indications for a changing local hydration environment of the ions were experimentally observed within the measured concentration range, the spectra of YbCl3 pointed towards formation of weak contact ion pairs. The proposed anion specificity for ion pairing was confirmed by supplementary Raman measurements.

  17. Investigation of atmospheric oxidation of propyl gallate in an anionic surfactant system in the absence and presence of ascorbic acid.

    PubMed

    Szymula, M

    2004-01-01

    The antioxidant efficiency of two hydrophilic species, ascorbic acid (AA) and propyl gallate (PG), in an anionic surfactant system are studied. Ascorbic acid and propyl gallate are dissolved/solubilized in a microemulsion formed by water, pentanol, and sodium dodecyl sulfate. The determination of propyl gallate decomposition/oxidation kinetics shows enhanced oxidation of PG with increasing pentanol concentration in the system. When ascorbic acid and propyl gallate are both present in water, in surfactant aqueous solution, and in the studied microemulsion systems, the molecular complex AAPG is formed. After some time the complex decomposes.

  18. Anion sensing with a Lewis acidic BODIPY-antimony(v) derivative.

    PubMed

    Christianson, Anna M; Gabbaï, François P

    2017-02-21

    We describe the synthesis of a BODIPY dye substituted with a Lewis acidic antimony(v) moiety. This compound, which has been fully characterized, shows a high affinity for small anions including fluoride and cyanide, the complexation of which elicits a fluorescence turn-on response.

  19. Protective activity of hamamelitannin on cell damage induced by superoxide anion radicals in murine dermal fibroblasts.

    PubMed

    Masaki, H; Atsumi, T; Sakurai, H

    1995-01-01

    Previously we demonstrated that hamamelitannin (2',5-di-O-galloyl hamamelose) in Hamamelis virginiana L. exhibits potent superoxide-anion scavenging activity. We then examined the physiological and pharmacological activities of hamamelitannin as well as its functional homologues, gallic acid and syringic acid. The following results were obtained: (1) Hamamelitannin has a higher protective activity against cell damages induced by superoxide anions than gallic acid which is the functional moiety of hamamelitannin. The protective activity of hamamelitannin on murine fibroblast-damage induced by superoxide anions was found at a minimum concentration of 50 microM, while the corresponding figure for gallic acid was 100 microM. (2) Pre-treatment of fibroblasts with hamamelitannin enhances cell survival. (3) The superoxide-anion scavenging activity of the compound in terms of its IC50 value (50% inhibition concentration of superoxide anion radicals generated) was evaluated by ESR spin-trapping. Both hamamelitannin (IC50 = 1.31 +/- 0.06 microM) and gallic acid (IC50 = 1.01 +/- 0.03 microM) exhibited high superoxide-anion scavenging activity followed by syringic acid (IC50 = 13.90 +/- 2.38 microM). (4) When hamamelitannin was treated with superoxide anions generated by a KO2-crown ether system, HPLC analysis showed the disappearance of hamamelitannin and the concomitant formation of hamamelitannin-derived radicals (g = 2.005, delta H1 = 2.16 G, delta H2 = 4.69 G) was detected by ESR spectrometry.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Photophysics and photochemistry of 2-aminobenzoic acid anion in aqueous solution.

    PubMed

    Pozdnyakov, Ivan P; Plyusnin, Victor F; Grivin, Vjacheslav P

    2009-12-24

    Nanosecond laser flash photolysis and absorption and fluorescence spectroscopy were used to study photochemical processes of 2-aminobenzoic acid anion (ABA(-)) in aqueous solutions. Excitation of this species gives rise to the ABA(-) triplet state to the ABA* radical and to the hydrated electron (e(aq)(-)). The last two species result from two-photon processes. In a neutral medium, the main decay channels of ABA(-) triplet state, the ABA* radical, and e(aq)(-) are T-T annihilation, recombination, and capture by the ABA(-) anion, respectively.

  1. Separation of thorium and uranium in nitric acid solution using silica based anion exchange resin.

    PubMed

    Chen, Yanliang; Wei, Yuezhou; He, Linfeng; Tang, Fangdong

    2016-09-30

    To separate thorium and uranium in nitric acid solution using anion exchange process, a strong base silica-based anion exchange resin (SiPyR-N4) was synthesized. Batch experiments were conducted and the separation factor of thorium and uranium in 9M nitric acid was about 10. Ion exchange chromatography was applied to separate thorium and uranium in different ratios. Uranium could be eluted by 9M nitric acid and thorium was eluted by 0.1M nitric acid. It was proved that thorium and uranium can be separated and recovered successfully by this method. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Effects of Low Phytanic Acid-Concentrated DHA on Activated Microglial Cells: Comparison with a Standard Phytanic Acid-Concentrated DHA.

    PubMed

    Ruiz-Roso, María Belén; Olivares-Álvaro, Elena; Quintela, José Carlos; Ballesteros, Sandra; Espinosa-Parrilla, Juan F; Ruiz-Roso, Baltasar; Lahera, Vicente; de Las Heras, Natalia; Martín-Fernández, Beatriz

    2018-05-30

    Docosahexaenoic acid (DHA, 22:6 n-3) is an essential omega-3 (ω-3) long chain polyunsaturated fatty acid of neuronal membranes involved in normal growth, development, and function. DHA has been proposed to reduce deleterious effects in neurodegenerative processes. Even though, some inconsistencies in findings from clinical and pre-clinical studies with DHA could be attributed to the presence of phytanic acid (PhA) in standard DHA treatments. Thus, the aim of our study was to analyze and compare the effects of a low PhA-concentrated DHA with a standard PhA-concentrated DHA under different neurotoxic conditions in BV-2 activated microglial cells. To this end, mouse microglial BV-2 cells were stimulated with either lipopolysaccharide (LPS) or hydrogen peroxide (H 2 O 2 ) and co-incubated with DHA 50 ppm of PhA (DHA (PhA:50)) or DHA 500 ppm of PhA (DHA (PhA:500)). Cell viability, superoxide anion (O 2 - ) production, Interleukin 6 (L-6), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), glutathione peroxidase (GtPx), glutathione reductase (GtRd), Caspase-3, and the brain-derived neurotrophic factor (BDNF) protein expression were explored. Low PhA-concentrated DHA protected against LPS or H 2 O 2 -induced cell viability reduction in BV-2 activated cells and O 2 - production reduction compared to DHA (PhA:500). Low PhA-concentrated DHA also decreased COX-2, IL-6, iNOS, GtPx, GtRd, and SOD-1 protein expression when compared to DHA (PhA:500). Furthermore, low PhA-concentrated DHA increased BDNF protein expression in comparison to DHA (PhA:500). The study provides data supporting the beneficial effect of low PhA-concentrated DHA in neurotoxic injury when compared to a standard PhA-concentrated DHA in activated microglia.

  3. NO3- anions can act as Lewis acid in the solid state

    NASA Astrophysics Data System (ADS)

    Bauzá, Antonio; Frontera, Antonio; Mooibroek, Tiddo J.

    2017-02-01

    Identifying electron donating and accepting moieties is crucial to understanding molecular aggregation, which is of pivotal significance to biology. Anions such as NO3- are typical electron donors. However, computations predict that the charge distribution of NO3- is anisotropic and minimal on nitrogen. Here we show that when the nitrate's charge is sufficiently dampened by resonating over a larger area, a Lewis acidic site emerges on nitrogen that can interact favourably with electron rich partners. Surveys of the Cambridge Structural Database and Protein Data Bank reveal geometric preferences of some oxygen and sulfur containing entities around a nitrate anion that are consistent with this `π-hole bonding' geometry. Computations reveal donor-acceptor orbital interactions that confirm the counterintuitive Lewis π-acidity of nitrate.

  4. Vaginal concentrations of lactic acid potently inactivate HIV

    PubMed Central

    Aldunate, Muriel; Tyssen, David; Johnson, Adam; Zakir, Tasnim; Sonza, Secondo; Moench, Thomas; Cone, Richard; Tachedjian, Gilda

    2013-01-01

    Objectives When Lactobacillus spp. dominate the vaginal microbiota of women of reproductive age they acidify the vagina to pH <4.0 by producing ∼1% lactic acid in a nearly racemic mixture of d- and l-isomers. We determined the HIV virucidal activity of racemic lactic acid, and its d- and l-isomers, compared with acetic acid and acidity alone (by the addition of HCl). Methods HIV-1 and HIV-2 were transiently treated with acids in the absence or presence of human genital secretions at 37°C for different time intervals, then immediately neutralized and residual infectivity determined in the TZM-bl reporter cell line. Results l-lactic acid at 0.3% (w/w) was 17-fold more potent than d-lactic acid in inactivating HIVBa-L. Complete inactivation of different HIV-1 subtypes and HIV-2 was achieved with ≥0.4% (w/w) l-lactic acid. At a typical vaginal pH of 3.8, l-lactic acid at 1% (w/w) more potently and rapidly inactivated HIVBa-L and HIV-1 transmitter/founder strains compared with 1% (w/w) acetic acid and with acidity alone, all adjusted to pH 3.8. A final concentration of 1% (w/w) l-lactic acid maximally inactivated HIVBa-L in the presence of cervicovaginal secretions and seminal plasma. The anti-HIV activity of l-lactic acid was pH dependent, being abrogated at neutral pH, indicating that its virucidal activity is mediated by protonated lactic acid and not the lactate anion. Conclusions l-lactic acid at physiological concentrations demonstrates potent HIV virucidal activity distinct from acidity alone and greater than acetic acid, suggesting a protective role in the sexual transmission of HIV. PMID:23657804

  5. Chloride concentration affects Kv channel voltage-gating kinetics: Importance of experimental anion concentrations.

    PubMed

    Bekar, L K; Loewen, M E; Forsyth, G W; Walz, W

    2005-09-30

    Chloride concentration has been shown to have a dramatic impact on protein folding and subsequent tertiary conformation [K.D. Collins, Ions from the Hofmeister series and osmolytes: effects on proteins in solution and in the crystallization process, Methods 34 (2004) 300-311; I. Jelesarov, E. Durr, R.M. Thomas, H.R. Bosshard, Salt effects on hydrophobic interaction and charge screening in the folding of a negatively charged peptide to a coiled coil (leucine zipper), Biochemistry 37 (1998) 7539-7550]. As it is known that Kv channel gating is linked to the stability of the cytoplasmic T1 multimerization domain conformation [D.L. Minor, Y.F. Lin, B.C. Mobley, A. Avelar, Y.N. Jan, L.Y. Jan, J.M. Berger, The polar T1 interface is linked to conformational changes that open the voltage-gated potassium channel, Cell 102 (2000) 657-670; B.A. Yi, D.L. Minor Jr., Y.F. Lin, Y.N. Jan, L.Y. Jan, Controlling potassium channel activities: interplay between the membrane and intracellular factors, Proc. Natl. Acad. Sci. U.S.A. 98 (2001) 11016-11023] and that intracellular chloride concentration has been linked to Kv channel kinetics [L.K. Bekar, W. Walz, Intracellular chloride modulates A-type potassium currents in astrocytes, Glia 39 (2002) 207-216; W.B. Thoreson, S.L. Stella, Anion modulation of calcium current voltage dependence and amplitude in salamander rods, Biochim. Biophys. Acta 1464 (2000) 142-150], the objective of the present study was to address how chloride concentration changes affect Kv channel kinetics more closely in an isolated expression system. Initially, no significant chloride concentration-dependent effects on channel steady-state gating kinetics were observed. Only after disruption of the cytoskeleton with cytochalasin-D did we see significant chloride concentration-dependent shifts in gating kinetics. This suggests that the shift in gating kinetics is mediated through effects of intracellular chloride concentration on cytoplasmic domain tertiary

  6. Anion channel sensitivity to cytosolic organic acids implicates a central role for oxaloacetate in integrating ion flux with metabolism in stomatal guard cells.

    PubMed

    Wang, Yizhou; Blatt, Michael R

    2011-10-01

    Stomatal guard cells play a key role in gas exchange for photosynthesis and in minimizing transpirational water loss from plants by opening and closing the stomatal pore. The bulk of the osmotic content driving stomatal movements depends on ionic fluxes across both the plasma membrane and tonoplast, the metabolism of organic acids, primarily Mal (malate), and its accumulation and loss. Anion channels at the plasma membrane are thought to comprise a major pathway for Mal efflux during stomatal closure, implicating their key role in linking solute flux with metabolism. Nonetheless, little is known of the regulation of anion channel current (I(Cl)) by cytosolic Mal or its immediate metabolite OAA (oxaloacetate). In the present study, we have examined the impact of Mal, OAA and of the monocarboxylic acid anion acetate in guard cells of Vicia faba L. and report that all three organic acids affect I(Cl), but with markedly different characteristics and sidedness to their activities. Most prominent was a suppression of ICl by OAA within the physiological range of concentrations found in vivo. These findings indicate a capacity for OAA to co-ordinate organic acid metabolism with I(Cl) through the direct effect of organic acid pool size. The findings of the present study also add perspective to in vivo recordings using acetate-based electrolytes.

  7. Enolate Stabilization by Anion-π Interactions: Deuterium Exchange in Malonate Dilactones on π-Acidic Surfaces.

    PubMed

    Miros, François N; Zhao, Yingjie; Sargsyan, Gevorg; Pupier, Marion; Besnard, Céline; Beuchat, César; Mareda, Jiri; Sakai, Naomi; Matile, Stefan

    2016-02-18

    Of central importance in chemistry and biology, enolate chemistry is an attractive topic to elaborate on possible contributions of anion-π interactions to catalysis. To demonstrate the existence of such contributions, experimental evidence for the stabilization of not only anions but also anionic intermediates and transition states on π-acidic aromatic surfaces is decisive. To tackle this challenge for enolate chemistry with maximal precision and minimal uncertainty, malonate dilactones are covalently positioned on the π-acidic surface of naphthalenediimides (NDIs). Their presence is directly visible in the upfield shifts of the α-protons in the (1) H NMR spectra. The reactivity of these protons on π-acidic surfaces is measured by hydrogen-deuterium (H-D) exchange for 11 different examples, excluding controls. The velocity of H-D exchange increases with π acidity (NDI core substituents: SO2 R>SOR>H>OR>OR/NR2 >SR>NR2 ). The H-D exchange kinetics vary with the structure of the enolate (malonates>methylmalonates, dilactones>dithiolactones). Moreover, they depend on the distance to the π surface (bridge length: 11-13 atoms). Most importantly, H-D exchange depends strongly on the chirality of the π surface (chiral sulfoxides as core substituents; the crystal structure of the enantiopure (R,R,P)-macrocycle is reported). For maximal π acidity, transition-state stabilizations up to -18.8 kJ mol(-1) are obtained for H-D exchange. The Brønsted acidity of the enols increases strongly with π acidity of the aromatic surface, the lowest measured pKa =10.9 calculates to a ΔpKa =-5.5. Corresponding to the deprotonation of arginine residues in neutral water, considered as "impossible" in biology, the found enolate-π interactions are very important. The strong dependence of enolate stabilization on the unprecedented seven-component π-acidity gradient over almost 1 eV demonstrates quantitatively that such important anion-π activities can be expected only from

  8. Anion capture and sensing with cationic boranes: on the synergy of Coulombic effects and onium ion-centred Lewis acidity.

    PubMed

    Zhao, Haiyan; Leamer, Lauren A; Gabbaï, François P

    2013-06-21

    Stimulated by the growing importance and recognized toxicity of anions such as fluoride, cyanide and azides, we have, in the past few years, developed a family of Lewis acidic triarylboranes that can be used for the complexation of these anions in organic and protic solvents, including water. A central aspect of our approach lies in the decoration of the boranes with peripheral ammonium, phosphonium, sulfonium stibonium or telluronium groups. The presence of these cationic groups provides a Coulombic drive for the capture of the anion, leading to boranes that can be used in aqueous solutions where anion hydration and/or protonation are usually competitive. The anion affinity of these boranes can be markedly enhanced by narrowing the separation between the anion binding site (i.e. the boron atom) and the onium ion. In such systems, the latent Lewis acidity of the onium ion also plays a role as manifested by the formation of B-X→E (E = P, S, Sb, or Te; X = F, CN or N3) chelate motifs that provide additional stability to the resulting complexes. These effects, which are maximum in stibonium and telluronium boranes, show that the Lewis acidity of heavy onium ions can be exploited for anion coordination and capture. The significance of these advances is illustrated by the development of applications in anion sensing, fluorination chemistry and (18)F radiolabeling for positron emission tomography.

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

    PubMed

    Voipio, Juha; Boron, Walter F; Jones, Stephen W; Hopfer, Ulrich; Payne, John A; Kaila, Kai

    2014-09-05

    Glykys et al. (Reports, 7 February 2014, p. 670) conclude that, rather than ion transporters, "local impermeant anions establish the neuronal chloride concentration" and thereby determine "the magnitude and direction of GABAAR currents at individual synapses." If this were possible, perpetual ion-motion machines could be constructed. The authors' conclusions conflict with basic thermodynamic principles. Copyright © 2014, American Association for the Advancement of Science.

  10. Separation of the rare earths by anion-exchange in the presence of lactic acid

    NASA Technical Reports Server (NTRS)

    Faris, J. P.

    1969-01-01

    Investigation of adsorption of rare earths and a few other elements to an anion-exchange resin from mixed solvents containing lactic acid shows that the lanthanides are absorbed more strongly than from the alpha-hydroxyisobutryric acid system, but with less separation between adjacent members of the series.

  11. Anion-π Catalysts with Axial Chirality.

    PubMed

    Wang, Chao; Matile, Stefan

    2017-09-04

    The idea of anion-π catalysis is to stabilize anionic transition states by anion-π interactions on aromatic surfaces. For asymmetric anion-π catalysis, π-acidic surfaces have been surrounded with stereogenic centers. This manuscript introduces the first anion-π catalysts that operate with axial chirality. Bifunctional catalysts with tertiary amine bases next to π-acidic naphthalenediimide planes are equipped with a bulky aromatic substituent in the imide position to produce separable atropisomers. The addition of malonic acid half thioesters to enolate acceptors is used for evaluation. In the presence of a chiral axis, the selective acceleration of the disfavored but relevant enolate addition was much better than with point chirality, and enantioselectivity could be observed for the first time for this reaction with small-molecule anion-π catalysts. Enantioselectivity increased with the π acidity of the π surface, whereas the addition of stereogenic centers around the aromatic plane did not cause further improvements. These results identify axial chirality of the active aromatic plane generated by atropisomerism as an attractive strategy for asymmetric anion-π catalysis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Kinetics of Corrosion Inhibition of Aluminum in Acidic Media by Water-Soluble Natural Polymeric Pectates as Anionic Polyelectrolyte Inhibitors.

    PubMed

    Hassan, Refat M; Zaafarany, Ishaq A

    2013-06-17

    Corrosion inhibition of aluminum (Al) in hydrochloric acid by anionic polyeletrolyte pectates (PEC) as a water-soluble natural polymer polysaccharide has been studied using both gasometric and weight loss techniques. The results drawn from these two techniques are comparable and exhibit negligible differences. The inhibition efficiency was found to increase with increasing inhibitor concentration and decrease with increasing temperature. The inhibition action of PEC on Al metal surface was found to obey the Freundlich isotherm. Factors such as the concentration and geometrical structure of the inhibitor, concentration of the corrosive medium, and temperature affecting the corrosion rates were examined. The kinetic parameters were evaluated and a suitable corrosion mechanism consistent with the kinetic results is discussed in the paper.

  13. Concentration of enteric viruses from tap water using an anion exchange resin-based method.

    PubMed

    Pérez-Méndez, A; Chandler, J C; Bisha, B; Goodridge, L D

    2014-09-01

    Detecting low concentrations of enteric viruses in water is needed for public health-related monitoring and control purposes. Thus, there is a need for sensitive, rapid and cost effective enteric viral concentration methods compatible with downstream molecular detection. Here, a virus concentration method based on adsorption of the virus to an anion exchange resin and direct isolation of nucleic acids is presented. Ten liter samples of tap water spiked with different concentrations (10-10,000 TCID50/10 L) of human adenovirus 40 (HAdV-40), hepatitis A virus (HAV) or rotavirus (RV) were concentrated and detected by real time PCR or real time RT-PCR. This method improved viral detection compared to direct testing of spiked water samples where the ΔCt was 12.1 for AdV-40 and 4.3 for HAV. Direct detection of RV in water was only possible for one of the three replicates tested (Ct of 37), but RV detection was improved using the resin method (all replicates tested positive with an average Ct of 30, n=3). The limit of detection of the method was 10 TCID50/10 L for HAdV-40 and HAV, and 100 TCID50/10 L of water for RV. These results compare favorably with detection limits reported for more expensive and laborious methods. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Chemiluminescence involving acidic and ambient ion light emitters. The chemiluminescence of the 9-acridinepercarboxylate anion

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

    White, E.H.; Roswell, D.F.; Dupont, A.C.

    The reaction of phenyl 9-acridinecarboxylate with an excess of peroxide ion in THF/water (67/33 mol %) leads to the emission of either bright yellow-green light or bright blue light, depending on the reaction conditions. The blue emission is favored by high concentrations of hydrogen peroxide and water, for example. 9-Acridinepercarboxylic acid is a common intermediate in the reactions. The light emitter responsible for the blue chemiluminescence is acridone, whereas that responsible for the yellow-green chemiluminescence is the anion of acridone. The effects of base concentration and solvent composition on the relative proportions of these two emitters have produced evidence that,more » contrary to the expectation of simple theory, a dioxetanone is not an intermediate in the reaction. Other cases where chemiluminescence may involve percarboxylate and peroxide ions are discussed.« less

  15. Stability of coordination compounds of Ni2+ and Co2+ ions with succinic acid anion in water-ethanol solvents

    NASA Astrophysics Data System (ADS)

    Tukumova, N. V.; Dieu Thuan, Tran Thi; Usacheva, T. R.; Koryshev, N. E.; Sharnin, V. A.

    2017-04-01

    Stability constants of the coordination compounds of nickel(II) and cobalt(II) ions with succinic acid anion in water-ethanol solvents are determined via potentiometric titration at ionic strength of 0.1 and at T = 298.15 K. It is found that logβ values of monoligand complexes of these ions and succinic acid anions rise along with the content of ethanol in solution ( X EtOH = 0-0.7 mole fractions). Based on an analysis of the thermodynamic characteristics of the solvation of the reagents involved in complex formation, it is found that the increased stability of succinate complexes of nickel(II) and cobalt(II) ions in water-ethanol solvents is mainly determined by the weakening of the solvation of succinic acid anion (Y2-).

  16. Reactivity of amino acid anions with nitrogen and oxygen atoms.

    PubMed

    Wang, Zhe-Chen; Li, Ya-Ke; He, Sheng-Gui; Bierbaum, Veronica M

    2018-02-14

    For many decades, astronomers have searched for biological molecules, including amino acids, in the interstellar medium; this endeavor is important for investigating the hypothesis of the origin of life from space. The space environment is complex and atomic species, such as nitrogen and oxygen atoms, are widely distributed. In this work, the reactions of eight typical deprotonated amino acids (glycine, alanine, cysteine, proline, aspartic acid, histidine, tyrosine, and tryptophan) with ground state nitrogen and oxygen atoms are studied by experiment and theory. These amino acid anions do not react with nitrogen atoms. However, the reactions of these ions with oxygen atoms show an intriguing variety of ionic products and the reaction rate constants are of the order of 10 -10 cm 3 s -1 . Density functional calculations provide detailed mechanisms of the reactions, and demonstrate that spin conversion is essential for some processes. Our study provides important data and insights for understanding the kinetic and dynamic behavior of amino acids in space environments.

  17. Kinetics of Corrosion Inhibition of Aluminum in Acidic Media by Water-Soluble Natural Polymeric Pectates as Anionic Polyelectrolyte Inhibitors

    PubMed Central

    Hassan, Refat M.; Zaafarany, Ishaq A.

    2013-01-01

    Corrosion inhibition of aluminum (Al) in hydrochloric acid by anionic polyeletrolyte pectates (PEC) as a water-soluble natural polymer polysaccharide has been studied using both gasometric and weight loss techniques. The results drawn from these two techniques are comparable and exhibit negligible differences. The inhibition efficiency was found to increase with increasing inhibitor concentration and decrease with increasing temperature. The inhibition action of PEC on Al metal surface was found to obey the Freundlich isotherm. Factors such as the concentration and geometrical structure of the inhibitor, concentration of the corrosive medium, and temperature affecting the corrosion rates were examined. The kinetic parameters were evaluated and a suitable corrosion mechanism consistent with the kinetic results is discussed in the paper. PMID:28809282

  18. L-shaped benzimidazole fluorophores: synthesis, characterization and optical response to bases, acids and anions.

    PubMed

    Lirag, Rio Carlo; Le, Ha T M; Miljanić, Ognjen Š

    2013-05-14

    Nine L-shaped benzimidazole fluorophores have been synthesized, computationally evaluated and spectroscopically characterized. These "half-cruciform" fluorophores respond to bases, acids and anions through changes in fluorescence that vary from moderate to dramatic.

  19. [Nutrition, acid-base metabolism, cation-anion difference and total base balance in humans].

    PubMed

    Mioni, R; Sala, P; Mioni, G

    2008-01-01

    The relationship between dietary intake and acid-base metabolism has been investigated in the past by means of the inorganic cation-anion difference (C(+)(nm)-A(-)(nm)) method based on dietary ash-acidity titration after the oxidative combustion of food samples. Besides the inorganic components of TA (A(-)(nm)-C(+)(nm)), which are under renal control, there are also metabolizable components (A(-)(nm)-C(+)(nm)) of TA, which are under the control of the intermediate metabolism. The whole body base balance, NBb(W), is obtained only by the application of C(+)(nm)-A(-)(nm) to food, feces and urine, while the metabolizable component (A(-)(nm)-C(+)(nm)) is disregarded. A novel method has been subsequently suggested to calculate the net balance of fixed acid, made up by the difference between the input of net endogenous acid production: NEAP = SO(4)(2-)+A(-)(m)-(C(+)(nm)-A(-)(nm)), and the output of net acid excretion: NAE = TA + NH(4)(+) - HCO(3)(-). This approach has been criticized because 1) it includes metabolizable acids, whose production cannot be measured independently; 2) the specific control of metabolizable acid and base has been incorrectly attributed to the kidney; 3) the inclusion of A-m in the balance input generates an acid overload; 4) the object of measurement in making up a balance has to be the same, a condition not fulfilled as NEAP is different from NAE. Lastly, by rearranging the net balance of the acid equation, the balance of nonmetabolizable acid equation is obtained. Therefore, any discrepancy between these two equations is due to the inaccuracy in the urine measurement of metabolizable cations and/or anions.

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

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

    Bowman-James, Kristen

    2004-12-01

    This project have focuses on the basic chemical aspects of anion receptor design of functional pH independent systems, with the ultimate goal of targeting the selective binding of sulfate, as well as design of separations strategies for selective and efficient removal of targeted anions. Key findings include: (1) the first synthetic sulfate-selective anion-binding agents; (2) simple, structure-based methods for modifying the intrinsic anion selectivity of a given class of anion receptors; and (3) the first system capable of extracting sulfate anion from acidic, nitrate-containing aqueous media. Areas probed during the last funding period include: the design, synthesis, and physical andmore » structural characterization of receptors and investigation of anion and dual ion pair extraction using lipophilic amide receptors for anion binding. A new collaboration has been added to the project in addition to the one with Dr. Bruce Moyer at Oak Ridge National Laboratory, with Professor Jonathan Sessler at the University of Texas at Austin.« less

  1. The anionic (9-methyladenine)-(1-methylthymine) base pair solvated by formic acid. A computational and photoelectron spectroscopy study.

    PubMed

    Storoniak, Piotr; Mazurkiewicz, Kamil; Haranczyk, Maciej; Gutowski, Maciej; Rak, Janusz; Eustis, Soren N; Ko, Yeon Jae; Wang, Haopeng; Bowen, Kit H

    2010-09-02

    The photoelectron spectrum for (1-methylthymine)-(9-methyladenine)...(formic acid) (1MT-9MA...FA) anions with the maximum at ca. 1.87 eV was recorded with 2.54 eV photons and interpreted through the quantum-chemical modeling carried out at the B3LYP/6-31+G(d,p) level. The relative free energies of the anions and their calculated vertical detachment energies suggest that only seven anionic structures contribute to the observed PES signal. We demonstrate that electron binding to the (1MT-9MA...FA) complex can trigger intermolecular proton transfer from formic acid, leading to the strong stabilization of the resulting radical anion. The SOMO distribution indicates that an excess electron may localize not only on the pyrimidine but also on the purine moiety. The biological context of DNA-environment interactions concerning the formation of single-strand breaks induced by excess electrons has been briefly discussed.

  2. Interaction and dynamics of ionic liquids based on choline and amino acid anions

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

    Campetella, M.; Bodo, E., E-mail: enrico.bodo@uniroma1.it; Caminiti, R., E-mail: ruggero.caminiti@uniroma1.it

    2015-06-21

    The combination of amino acid anions with the choline cation gives origin to a new and potentially important class of organic ionic liquids that might represent a viable and bio-compatible alternative with respect to the traditional ones. We present here a detailed study of the bulk phase of the prototype system composed of the simplest amino acid (alanine) anion and the choline cation, based on ab initio and classical molecular dynamics. Theoretical findings have been validated by comparing with accurate experimental X-ray diffraction data and infrared spectra. We find that hydrogen bonding (HB) features in these systems are crucial inmore » establishing their local geometric structure. We have also found that these HBs once formed are persistent and that the proton resides exclusively on the choline cation. In addition, we show that a classical force field description for this particular ionic liquid can be accurately performed by using a slightly modified version of the generalized AMBER force field.« less

  3. Interaction and dynamics of ionic liquids based on choline and amino acid anions

    NASA Astrophysics Data System (ADS)

    Campetella, M.; Bodo, E.; Caminiti, R.; Martino, A.; D'Apuzzo, F.; Lupi, S.; Gontrani, L.

    2015-06-01

    The combination of amino acid anions with the choline cation gives origin to a new and potentially important class of organic ionic liquids that might represent a viable and bio-compatible alternative with respect to the traditional ones. We present here a detailed study of the bulk phase of the prototype system composed of the simplest amino acid (alanine) anion and the choline cation, based on ab initio and classical molecular dynamics. Theoretical findings have been validated by comparing with accurate experimental X-ray diffraction data and infrared spectra. We find that hydrogen bonding (HB) features in these systems are crucial in establishing their local geometric structure. We have also found that these HBs once formed are persistent and that the proton resides exclusively on the choline cation. In addition, we show that a classical force field description for this particular ionic liquid can be accurately performed by using a slightly modified version of the generalized AMBER force field.

  4. Determination of uranium isotopes in environmental samples by anion exchange in sulfuric and hydrochloric acid media.

    PubMed

    Popov, L

    2016-09-01

    Method for determination of uranium isotopes in various environmental samples is presented. The major advantages of the method are the low cost of the analysis, high radiochemical yields and good decontamination factors from the matrix elements, natural and man-made radionuclides. The separation and purification of uranium is attained by adsorption with strong base anion exchange resin in sulfuric and hydrochloric acid media. Uranium is electrodeposited on a stainless steel disk and measured by alpha spectrometry. The analytical method has been applied for the determination of concentrations of uranium isotopes in mineral, spring and tap waters from Bulgaria. The analytical quality was checked by analyzing reference materials. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Concentration of perrhenate and pertechnetate solutions

    DOEpatents

    Knapp, F.F.; Beets, A.L.; Mirzadeh, S.; Guhlke, S.

    1998-03-17

    A method is described for preparing a concentrated solution of a carrier-free radioisotope which includes the steps of: (a) providing a generator column loaded with a composition containing a parent radioisotope; (b) eluting the generator column with an eluent solution which includes a salt of a weak acid to elute a target daughter radioisotope from the generator column in a first eluate; (c) eluting a cation-exchange column with the first eluate to exchange cations of the salt for hydrogen ions and to elute the target daughter radioisotope and a weak acid in a second eluate; (d) eluting an anion-exchange column with the second eluate to trap and concentrate the target daughter radioisotope and to elute the weak acid solution therefrom; and (e) eluting the concentrated target daughter radioisotope from the anion-exchange column with a saline solution. 1 fig.

  6. Concentration of perrhenate and pertechnetate solutions

    DOEpatents

    Knapp, Furn F.; Beets, Arnold L.; Mirzadeh, Saed; Guhlke, Stefan

    1998-01-01

    A method of preparing a concentrated solution of a carrier-free radioisotope which includes the steps of: a. providing a generator column loaded with a composition containing a parent radioisotope; b. eluting the generator column with an eluent solution which includes a salt of a weak acid to elute a target daughter radioisotope from the generator column in a first eluate. c. eluting a cation-exchange column with the first eluate to exchange cations of the salt for hydrogen ions and to elute the target daughter radioisotope and a weak acid in a second eluate; d. eluting an anion-exchange column with the second eluate to trap and concentrate the target daughter radioisotope and to elute the weak acid solution therefrom; and e. eluting the concentrated target daughter radioisotope from the anion-exchange column with a saline solution.

  7. A preference for edgewise interactions between aromatic rings and carboxylate anions: the biological relevance of anion-quadrupole interactions.

    PubMed

    Jackson, Michael R; Beahm, Robert; Duvvuru, Suman; Narasimhan, Chandrasegara; Wu, Jun; Wang, Hsin-Neng; Philip, Vivek M; Hinde, Robert J; Howell, Elizabeth E

    2007-07-19

    Noncovalent interactions are quite important in biological structure-function relationships. To study the pairwise interaction of aromatic amino acids (phenylalanine, tyrosine, tryptophan) with anionic amino acids (aspartic and glutamic acids), small molecule mimics (benzene, phenol or indole interacting with formate) were used at the MP2 level of theory. The overall energy associated with an anion-quadrupole interaction is substantial (-9.5 kcal/mol for a benzene-formate planar dimer at van der Waals contact distance), indicating the electropositive ring edge of an aromatic group can interact with an anion. Deconvolution of the long-range coplanar interaction energy into fractional contributions from charge-quadrupole interactions, higher-order electrostatic interactions, and polarization terms was achieved. The charge-quadrupole term contributes between 30 to 45% of the total MP2 benzene-formate interaction; most of the rest of the interaction arises from polarization contributions. Additional studies of the Protein Data Bank (PDB Select) show that nearly planar aromatic-anionic amino acid pairs occur more often than expected from a random angular distribution, while axial aromatic-anionic pairs occur less often than expected; this demonstrates the biological relevance of the anion-quadrupole interaction. While water may mitigate the strength of these interactions, they may be numerous in a typical protein structure, so their cumulative effect could be substantial.

  8. Kinetics of corrosion inhibition of aluminum in acidic media by water-soluble natural polymeric chondroitin-4-sulfate as anionic polyelectrolyte inhibitor.

    PubMed

    Hassan, Refat M; Ibrahim, Samia M; Takagi, Hideo D; Sayed, Suzan A

    2018-07-15

    Corrosion inhibition of aluminum (Al) in hydrochloric acid by anionic polyelectrolyte chondroitin-4-sulfate (CS) polysaccharide has been studied using both gasometrical and weight-loss techniques. The results drawn from these two techniques are comparable and exhibit negligible differences. The inhibition efficiency was found to increase with increasing the inhibitor concentration and decreased with increasing temperature. The inhibition action of CS on Al metal surface was found to obey both of Langmuir and Freundlich isotherms. The factors affecting the corrosion rates such as the concentration and geometrical structure of the inhibitor, concentration of the corrosive medium, and the temperature were examined. The kinetic parameters were evaluated and a suitable corrosion mechanism consistent with the results obtained is discussed. Copyright © 2018. Published by Elsevier Ltd.

  9. Determination of Amino Acids in Cell Culture and Fermentation Broth Media Using Anion-Exchange Chromatography with Integrated Pulsed Amperometric Detection

    PubMed Central

    Hanko, Valoran P.; Heckenberg, Andrea; Rohrer, Jeffrey S.

    2004-01-01

    Anion-exchange chromatography with integrated pulsed amperometric detection (AE-IPAD) separates and directly detects amino acids, carbohydrates, alditols, and glycols in the same injection without pre- or post-column derivatization. These separations use a combination of NaOH and NaOH/sodium acetate eluents. We previously published the successful use of this technique, also known as AAA-Direct, to determine free amino acids in cell culture and fermentation broth media. We showed that retention of carbohydrates varies with eluent NaOH concentration differently than amino acids, and thus separations can be optimized by varying the initial NaOH concentration and its duration. Unfortunately, some amino acids eluting in the acetate gradient portion of the method were not completely resolved from system-related peaks and from unknown peaks in complex cell culture and fermentation media. In this article, we present changes in method that improve amino acid resolution and system ruggedness. The success of these changes and their compatibility with the separations previously designed for fermentation and cell culture are demonstrated with yeast extract-peptone-dextrose broth, M199, Dulbecco’s modified Eagle’s (with F-12), L-15 (Leibovitz), and McCoy’s 5A cell culture media. PMID:15585828

  10. Essential role for uncoupling protein-3 in mitochondrial adaptation to fasting but not in fatty acid oxidation or fatty acid anion export.

    PubMed

    Seifert, Erin L; Bézaire, Véronic; Estey, Carmen; Harper, Mary-Ellen

    2008-09-12

    Uncoupling protein-3 (UCP3) is a mitochondrial inner membrane protein expressed most abundantly in skeletal muscle and to a lesser extent in heart and brown adipose tissue. Evidence supports a role for UCP3 in fatty acid oxidation (FAO); however, the underlying mechanism has not been explored. In 2001 we proposed a role for UCP3 in fatty acid export, leading to higher FAO rates (Himms-Hagen, J., and Harper, M. E. (2001) Exp. Biol. Med. (Maywood) 226, 78-84). Specifically, this widely held hypothesis states that during elevated FAO rates, UCP3 exports fatty acid anions, thereby maintaining mitochondrial co-enzyme A availability; reactivation of exported fatty acid anions would ultimately enable increased FAO. Here we tested mechanistic aspects of this hypothesis as well as its functional implications, namely increased FAO rates. Using complementary mechanistic approaches in mitochondria from wild-type and Ucp3(-/-) mice, we find that UCP3 is not required for FAO regardless of substrate type or supply rate covering a 20-fold range. Fatty acid anion export and reoxidation during elevated FAO, although present in skeletal muscle mitochondria, are independent of UCP3 abundance. Interestingly, UCP3 was found to be necessary for the fasting-induced enhancement of FAO rate and capacity, possibly via mitigated mitochondrial oxidative stress. Thus, although our observations indicate that UCP3 can impact FAO rates, the mechanistic basis is not via an integral function for UCP3 in the FAO machinery. Overall our data indicate a function for UCP3 in mitochondrial adaptation to perturbed cellular energy balance and integrate previous observations that have linked UCP3 to reduced oxidative stress and FAO.

  11. Anionic 11-mercaptoundecanoic acid capped ZnO nanoparticles

    NASA Astrophysics Data System (ADS)

    Šimšíková, Michaela; Antalík, Marián; Kaňuchová, Mária; Škvarla, Jiří

    2013-10-01

    The anionic zinc oxide nanoparticles have been prepared at room temperature by a precipitation method using ZnCl2 and NaOH and surface modification with 11-mercaptoundecanoic acid (MUA). Atomic force microscopy (AFM) was used for definition of morphology and size of prepared nanoparticles which was proved by measurements of particle size distribution using Zetasizer. Successful coating with MUA as surfactant was acknowledged by X-ray photoelectron spectroscopy and ATR FT-IR spectroscopy. The isoelectric point (IEP) of ZnO-MUA nanoparticles was obtained by measurements of zeta potential and FT-IR dependence on pH; the obtained value was approximately 3.58. The value of exchanged protons was 2.88 which indicates a positive binding cooperativity of modified nanoparticles.

  12. A systematic tandem mass spectrometric study of anion attachment for improved detection and acidity evaluation of nitrogen-rich energetic compounds.

    PubMed

    Gaiffe, Gabriel; Bridoux, Maxime C; Costanza, Christine; Cole, Richard B

    2018-01-01

    The development of rapid, efficient, and reliable detection methods for the characterization of energetic compounds is of high importance to security forces concerned with terrorist threats. With a mass spectrometric approach, characteristic ions can be produced by attaching anions to analyte molecules in the negative ion mode of electrospray ionization mass spectrometry (ESI-MS). Under optimized conditions, formed anionic adducts can be detected with higher sensitivities as compared with the deprotonated molecules. Fundamental aspects pertaining to the formation of anionic adducts of 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX), 1,3,5-trinitro-1,3,5-triazinane (RDX), pentaerythritol tetranitrate (PETN), nitroglycerin (NG), and 1,3,5-trinitroso-1,3,5-triazinane energetic (R-salt) compounds using various anions have been systematically studied by ESI-MS and ESI tandem mass spectrometry (collision-induced dissociation) experiments. Bracketing method results show that the gas-phase acidities of PETN, RDX, and HMX fall between those of HF and acetic acid. Moreover, PETN and RDX are each less acidic than HMX in the gas phase. Nitroglycerin was found to be the most acidic among the nitrogen-rich explosives studied. The ensemble of bracketing results allows the construction of the following ranking of gas-phase acidities: PETN (1530-1458 kJ/mol) > RDX (approximately 1458 kJ/mol) > HMX (approximately 1433 kJ/mol) > nitroglycerin (1427-1327.8 kJ/mol). Copyright © 2017 John Wiley & Sons, Ltd.

  13. Sulfidic Anion Concentrations on Early Earth for Surficial Origins-of-Life Chemistry.

    PubMed

    Ranjan, Sukrit; Todd, Zoe R; Sutherland, John D; Sasselov, Dimitar D

    2018-04-08

    A key challenge in origin-of-life studies is understanding the environmental conditions on early Earth under which abiogenesis occurred. While some constraints do exist (e.g., zircon evidence for surface liquid water), relatively few constraints exist on the abundances of trace chemical species, which are relevant to assessing the plausibility and guiding the development of postulated prebiotic chemical pathways which depend on these species. In this work, we combine literature photochemistry models with simple equilibrium chemistry calculations to place constraints on the plausible range of concentrations of sulfidic anions (HS - , HSO 3 - , SO 3 2- ) available in surficial aquatic reservoirs on early Earth due to outgassing of SO 2 and H 2 S and their dissolution into small shallow surface water reservoirs like lakes. We find that this mechanism could have supplied prebiotically relevant levels of SO 2 -derived anions, but not H 2 S-derived anions. Radiative transfer modeling suggests UV light would have remained abundant on the planet surface for all but the largest volcanic explosions. We apply our results to the case study of the proposed prebiotic reaction network of Patel et al. ( 2015 ) and discuss the implications for improving its prebiotic plausibility. In general, epochs of moderately high volcanism could have been especially conducive to cyanosulfidic prebiotic chemistry. Our work can be similarly applied to assess and improve the prebiotic plausibility of other postulated surficial prebiotic chemistries that are sensitive to sulfidic anions, and our methods adapted to study other atmospherically derived trace species. Key Words: Early Earth-Origin of life-Prebiotic chemistry-Volcanism-UV radiation-Planetary environments. Astrobiology 18, xxx-xxx.

  14. Analyses of sulfonamide antibiotics by a successive anion- and cation-selective injection coupled to microemulsion electrokinetic chromatography.

    PubMed

    Lin, Yun-Ta; Liu, Yu-Wei; Cheng, Yi-Jie; Huang, Hsi-Ya

    2010-07-01

    In this study, an MEEKC was used to detect and analyze nine sulfonamide antibiotics. Owing to an insufficient sensitivity of on-column UV detection, a field-amplified sample injection, successive anion- and cation-selective injection, was used for the on-line concentration of the nine antibiotics. In the successive anion- and cation-selective injection mode, a leading water plug was introduced prior to anion injection, and then an acidic plug followed by a terminal water plug had to be used before subsequent cation injection. The results indicated some sulfonamides (sulfamonomethoxine, sulfamethazine, sulfamerazine and sulfadiazine) were determined as split signals in pairs, and this was likely due to the use of a longer acid plug (360 s) which caused the sulfonamide anions and cations to be stacked in two distinct zones of the leading water and acid plugs. Meanwhile, all the sulfonamides that were introduced either by anion or cation injection were stacked within the leading water plug when a shorter acid plug (210 s) was used. As a result, the nine sulfonamides were determined as single and symmetrical peaks with low LODs (0.9-4.2 microg/L). Furthermore, the MEEKC method was successfully applied for the detection of trace sulfonamide residues in several food and water samples.

  15. Sensitive determination of anions in saliva using capillary electrophoresis after transient isotachophoretic preconcentration.

    PubMed

    Xu, Zhongqi; Doi, Takayuki; Timerbaev, Andrei R; Hirokawa, Takeshi

    2008-10-19

    A transient isotachophoresis-capillary electrophoresis (tITP-CE) system for the determination of minor inorganic anions in saliva is described. The complete separation and quantification of bromide, iodide, nitrate, nitrite, and thiocyanate has been achieved with only centrifugation and dilution of the saliva sample. In-line tITP preconcentration conditions, created by introduction of the plugs of 5 mM dithionic acid (leading electrolyte) and 10 mM formic acid (terminating electrolyte) before and after the sample zone, respectively, allowed the limits of direct UV absorption detection (at 200 nm) to be up to 50-fold improved as compared with CE without tITP. As a result, nitrate and thiocyanate were still detectable at 4.6 and 3.8 microgl(-1), respectively, in 1000 times diluted saliva. The daily variations of anionic concentrations in saliva samples taken from a smoking health volunteer were discussed based on the results of tITP-CE analysis. It was confirmed that the thiocyanate concentration in saliva noticeably increased after smoking. This is apparently the first report on simultaneous quantification of more than four anionic salivary constituents using CE.

  16. Chitosan as cationic polyelectrolyte for the modification of electroosmotic flow and its utilization for the separation of inorganic anions by capillary zone electrophoresis.

    PubMed

    Takayanagi, Toshio; Motomizu, Shoji

    2006-09-01

    Cationic polyelectrolyte of chitosan was used for the reversal of electroosmotic flow in capillary zone electrophoresis. The chitosan was dissolved in acetic acid solution, and stable electroosmotic flow was obtained at the chitosan concentrations between 50 and 300 microg/mL. Separation of inorganic anions was carried out using the dynamically coated capillary by capillary zone electrophoresis. Nine kinds of anions were separated and detected with the capillary. The electrophoretic mobility of the analyte anions decreased with increasing concentrations of chitosan in the migrating solution through ion-ion interaction, but the migration order of the analyte anions was not changed in the concentration range of the chitosan examined. The signal shape for the analyte anions was developed by using field-enhanced sample stacking with 10 mM sodium sulfate.

  17. Snowmelt controls on concentration-discharge relationships and the balance of oxidative and acid-base weathering fluxes in an alpine catchment, East River, Colorado: ACID-BASE VERSUS OXIDATIVE WEATHERING FLUXES

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

    Winnick, Matthew J.; Carroll, Rosemary W. H.; Williams, Kenneth H.

    Although important for riverine solute and nutrient fluxes, the connections between biogeochemical processes and subsurface hydrology remain poorly characterized. We investigate these couplings in the East River, CO, a high-elevation shale-dominated catchment in the Rocky Mountains, using concentration-discharge (C-Q) relationships for major cations, anions, and organic carbon. Dissolved organic carbon (DOC) displays a positive C-Q relationship with clockwise hysteresis, indicating mobilization and depletion of DOC in the upper soil horizons and emphasizing the importance of shallow flowpaths during snowmelt. Cation and anion concentrations demonstrate that carbonate weathering, which dominates solute fluxes, is promoted by both sulfuric acid derived from pyritemore » oxidation in the shale bedrock and carbonic acid derived from subsurface respiration. Sulfuric acid weathering dominates during baseflow conditions when waters infiltrate below the inferred pyrite oxidation front, whereas carbonic acid weathering plays a dominant role during snowmelt as a result of shallow flowpaths. Differential C-Q relationships between solutes suggest that infiltrating waters approach calcite saturation before reaching the pyrite oxidation front, after which sulfuric acid reduces carbonate alkalinity. This reduction in alkalinity results in CO 2 outgassing when waters equilibrate to surface conditions, and reduces the riverine export of carbon and alkalinity by roughly 33% annually. In conclusion, future changes in snowmelt dynamics that control the balance of carbonic and sulfuric acid weathering may substantially alter carbon cycling in the East River. Ultimately, we demonstrate that differential C-Q relationships between major solutes can provide unique insights into the complex subsurface flow and biogeochemical dynamics that operate at catchment scales.« less

  18. Snowmelt controls on concentration-discharge relationships and the balance of oxidative and acid-base weathering fluxes in an alpine catchment, East River, Colorado: ACID-BASE VERSUS OXIDATIVE WEATHERING FLUXES

    DOE PAGES

    Winnick, Matthew J.; Carroll, Rosemary W. H.; Williams, Kenneth H.; ...

    2017-03-01

    Although important for riverine solute and nutrient fluxes, the connections between biogeochemical processes and subsurface hydrology remain poorly characterized. We investigate these couplings in the East River, CO, a high-elevation shale-dominated catchment in the Rocky Mountains, using concentration-discharge (C-Q) relationships for major cations, anions, and organic carbon. Dissolved organic carbon (DOC) displays a positive C-Q relationship with clockwise hysteresis, indicating mobilization and depletion of DOC in the upper soil horizons and emphasizing the importance of shallow flowpaths during snowmelt. Cation and anion concentrations demonstrate that carbonate weathering, which dominates solute fluxes, is promoted by both sulfuric acid derived from pyritemore » oxidation in the shale bedrock and carbonic acid derived from subsurface respiration. Sulfuric acid weathering dominates during baseflow conditions when waters infiltrate below the inferred pyrite oxidation front, whereas carbonic acid weathering plays a dominant role during snowmelt as a result of shallow flowpaths. Differential C-Q relationships between solutes suggest that infiltrating waters approach calcite saturation before reaching the pyrite oxidation front, after which sulfuric acid reduces carbonate alkalinity. This reduction in alkalinity results in CO 2 outgassing when waters equilibrate to surface conditions, and reduces the riverine export of carbon and alkalinity by roughly 33% annually. In conclusion, future changes in snowmelt dynamics that control the balance of carbonic and sulfuric acid weathering may substantially alter carbon cycling in the East River. Ultimately, we demonstrate that differential C-Q relationships between major solutes can provide unique insights into the complex subsurface flow and biogeochemical dynamics that operate at catchment scales.« less

  19. Anionic magnetite nanoparticle conjugated with pyrrolidinyl peptide nucleic acid for DNA base discrimination

    NASA Astrophysics Data System (ADS)

    Khadsai, Sudarat; Rutnakornpituk, Boonjira; Vilaivan, Tirayut; Nakkuntod, Maliwan; Rutnakornpituk, Metha

    2016-09-01

    Magnetite nanoparticles (MNPs) were surface modified with anionic poly( N-acryloyl glycine) (PNAG) and streptavidin for specific interaction with biotin-conjugated pyrrolidinyl peptide nucleic acid (PNA). Hydrodynamic size ( D h) of PNAG-grafted MNPs varied from 334 to 496 nm depending on the loading ratio of the MNP to NAG in the reaction. UV-visible and fluorescence spectrophotometries were used to confirm the successful immobilization of streptavidin and PNA on the MNPs. About 291 pmol of the PNA/mg MNP was immobilized on the particle surface. The PNA-functionalized MNPs were effectively used as solid supports to differentiate between fully complementary and non-complementary/single-base mismatch DNA using the PNA probe. These novel anionic MNPs can be efficiently applicable for use as a magnetically guidable support for DNA base discrimination.

  20. Extraction of anionic dye from aqueous solutions by emulsion liquid membrane.

    PubMed

    Dâas, Attef; Hamdaoui, Oualid

    2010-06-15

    In this work, the extraction of Congo red (CR), an anionic disazo direct dye, from aqueous solutions by emulsion liquid membrane (ELM) was investigated. The important operational parameters governing emulsion stability and extraction behavior of dye were studied. The extraction of CR was influenced by a number of variables such as surfactant concentration, stirring speed, acid concentration in the feed solution and volume ratios of internal phase to organic phase and of emulsion to feed solution. Under most favorable conditions, practically all the CR molecules present in the feed phase were extracted even in the presence of salt (NaCl). At the optimum experimental conditions, total removal of antharaquinonic dye Acid Blue 25 was attained after only 10 min. Influence of sodium carbonate concentration as internal receiving phase on the stripping efficiency of CR was examined. The best sodium carbonate concentration in the internal phase that conducted to excellent stripping efficiency (>99%) and emulsion stability was 0.1N. The membrane recovery was total and the permeation of CR was not decreased up to seven runs. ELM process is a promising alternative to conventional methods and should increase awareness of the potential for recovery of anionic dyes. Copyright 2010 Elsevier B.V. All rights reserved.

  1. The effect of cation source and dietary cation-anion difference on rumen ion concentrations in lactating dairy cows.

    PubMed

    Catterton, T L; Erdman, R A

    2016-08-01

    Many studies have focused on the influence of dietary cation-anion difference (DCAD) on animal performance but few have examined the effect of DCAD on the rumen ionic environment. The objective of this study was to examine the effects of DCAD, cation source (Na vs. K), and anion source (Cl vs. bicarbonate or carbonate) on rumen environment and fermentation. The study used 5 rumen-fistulated dairy cows and 5 dietary treatments that were applied using a 5×5 Latin square design with 2-wk experimental periods. Treatments consisted of (1) the basal total mixed ration (TMR); (2) the basal TMR plus 340mEq/kg of Na (dry matter basis) using NaCl; (3) the basal TMR plus 340mEq/kg of K using KCl; (4) the basal TMR plus 340mEq/kg of Na using NaHCO3; and (5) the basal TMR plus 340mEq/kg of K using K2CO3. On the last day of each experimental period, rumen samples were collected and pooled from 5 different locations at 0, 1.5, 3, 4.5, 6, 9, and 12h postfeeding for measurement of rumen pH and concentrations of strong ions and volatile fatty acids (VFA). Dietary supplementation of individual strong ions increased the corresponding rumen ion concentration. Rumen Na was decreased by 24mEq/L when K was substituted for Na in the diet, but added dietary Na had no effect on rumen K. Rumen Cl was increased by 10mEq/L in diets supplemented with Cl. Cation source had no effect on rumen pH or total VFA concentration. Increased DCAD increased rumen pH by 0.10 pH units and increased rumen acetate by 4mEq/L but did not increase total VFA. This study demonstrated that rumen ion concentrations can be manipulated by dietary ion concentrations. If production and feed efficiency responses to DCAD and ionophores in the diet are affected by rumen Na and K concentrations, then manipulating dietary Na and K could be used either to enhance or diminish those responses. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  2. Modeling the oxidation kinetics of sono-activated persulfate's process on the degradation of humic acid.

    PubMed

    Songlin, Wang; Ning, Zhou; Si, Wu; Qi, Zhang; Zhi, Yang

    2015-03-01

    Ultrasound degradation of humic acid has been investigated in the presence of persulfate anions at ultrasonic frequency of 40 kHz. The effects of persulfate anion concentration, ultrasonic power input, humic acid concentration, reaction time, solution pH and temperature on humic acid removal efficiency were studied. It is found that up to 90% humic acid removal efficiency was achieved after 2 h reaction. In this system, sulfate radicals (SO₄⁻·) were considered to be the mainly oxidant to mineralize humic acid while persulfate anion can hardly react with humic acid directly. A novel kinetic model based on sulfate radicals (SO₄⁻·) oxidation was established to describe the humic acid mineralization process mathematically and chemically in sono-activated persulfate system. According to the new model, ultrasound power, persulfate dosage, solution pH and reaction temperature have great influence on humic acid degradation. Different initial concentration of persulfate anions and humic acid, ultrasonic power, initial pH and reaction temperature have been discussed to valid the effectiveness of the model, and the simulated data showed new model had good agreement with the experiments data.

  3. Isatinphenylsemicarbazones as efficient colorimetric sensors for fluoride and acetate anions - anions induce tautomerism.

    PubMed

    Jakusová, Klaudia; Donovalová, Jana; Cigáň, Marek; Gáplovský, Martin; Garaj, Vladimír; Gáplovský, Anton

    2014-04-05

    The anion induced tautomerism of isatin-3-4-phenyl(semicarbazone) derivatives is studied herein. The interaction of F(-), AcO(-), H2PO4(-), Br(-) or HSO4(-) anions with E and Z isomers of isatin-3-4-phenyl(semicarbazone) and N-methylisatin-3-4-phenyl(semicarbazone) as sensors influences the tautomeric equilibrium of these sensors in the liquid phase. This tautomeric equilibrium is affected by (1) the inter- and intra-molecular interactions' modulation of isatinphenylsemicarbazone molecules due to the anion induced change in the solvation shell of receptor molecules and (2) the sensor-anion interaction with the urea hydrogens. The acid-base properties of anions and the difference in sensor structure influence the equilibrium ratio of the individual tautomeric forms. Here, the tautomeric equilibrium changes were indicated by "naked-eye" experiment, UV-VIS spectral and (1)H NMR titration, resulting in confirmation that appropriate selection of experimental conditions leads to a high degree of sensor selectivity for some investigated anions. Sensors' E and Z isomers differ in sensitivity, selectivity and sensing mechanism. Detection of F(-) or CH3COO(-) anions at high weakly basic anions' excess is possible. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Single-Photon, Double Photodetachment of Nickel Phthalocyanine Tetrasulfonic Acid 4- Anions.

    PubMed

    Daly, Steven; Girod, Marion; Vojkovic, Marin; Giuliani, Alexandre; Antoine, Rodolphe; Nahon, Laurent; O'Hair, Richard A J; Dugourd, Philippe

    2016-07-07

    Single-photon, two-electron photodetachment from nickel phthalocyanine tetrasulfonic acid tetra anions, [NiPc](4-), was examined in the gas-phase using a linear ion trap coupled to the DESIRS VUV beamline of the SOLEIL Synchrotron. This system was chosen since it has a low detachment energy, known charge localization, and well-defined geometrical and electronic structures. A threshold for two-electron loss is observed at 10.2 eV, around 1 eV lower than previously observed double detachment thresholds on multiple charged protein anions. The photodetachment energy of [NiPc](4-) has been previously determined to be 3.5 eV and the photodetachment energy of [NiPc](3-•) is determined in this work to be 4.3 eV. The observed single photon double electron detachment threshold is hence 5.9 eV higher than the energy required for sequential single electron loss. Possible mechanisms are for double photodetachment are discussed. These observations pave the way toward new, exciting experiments for probing double photodetachment at relatively low energies, including correlation measurements on emitted photoelectrons.

  5. Studies of anions sorption on natural zeolites.

    PubMed

    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. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Metabolic Acidosis or Respiratory Alkalosis? Evaluation of a Low Plasma Bicarbonate Using the Urine Anion Gap.

    PubMed

    Batlle, Daniel; Chin-Theodorou, Jamie; Tucker, Bryan M

    2017-09-01

    Hypobicarbonatemia, or a reduced bicarbonate concentration in plasma, is a finding seen in 3 acid-base disorders: metabolic acidosis, chronic respiratory alkalosis and mixed metabolic acidosis and chronic respiratory alkalosis. Hypobicarbonatemia due to chronic respiratory alkalosis is often misdiagnosed as a metabolic acidosis and mistreated with the administration of alkali therapy. Proper diagnosis of the cause of hypobicarbonatemia requires integration of the laboratory values, arterial blood gas, and clinical history. The information derived from the urinary response to the prevailing acid-base disorder is useful to arrive at the correct diagnosis. We discuss the use of urine anion gap, as a surrogate marker of urine ammonium excretion, in the evaluation of a patient with low plasma bicarbonate concentration to differentiate between metabolic acidosis and chronic respiratory alkalosis. The interpretation and limitations of urine acid-base indexes at bedside (urine pH, urine bicarbonate, and urine anion gap) to evaluate urine acidification are discussed. Copyright © 2017 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  7. Dehydroacetic Acid Derivatives Bearing Amide or Urea Moieties as Effective Anion Receptors.

    PubMed

    Bregović, Nikola; Cindro, Nikola; Bertoša, Branimir; Barišić, Dajana; Frkanec, Leo; Užarević, Krunoslav; Tomišić, Vladislav

    2017-08-01

    Derivatives of dehydroacetic acid comprising amide or urea subunits have been synthesized and their anion-binding properties investigated. Among a series of halides and oxyanions, the studied compounds selectively bind acetate and dihydrogen phosphate in acetonitrile and dimethyl sulfoxide. The corresponding complexation processes were characterized by means of 1 H NMR titrations, which revealed a 1:1 complex stoichiometry in most cases, with the exception of dihydrogen phosphate, which formed 2:1 (anion/ligand) complexes in acetonitrile. The complex stability constants were determined and are discussed with respect to the structural properties of the receptors, the hydrogen-bond-forming potential of the anions, and the characteristics of the solvents used. Based on the spectroscopic data and results of Monte Carlo simulations, the amide or urea groups were affirmed as the primary binding sites in all cases. The results of the computational methods indicate that an array of both inter- and intramolecular hydrogen bonds can form in the studied systems, and these were shown to play an important role in defining the overall stability of the complexes. Solubility measurements were carried out in both solvents and the thermodynamics of transfer from acetonitrile to dimethyl sulfoxide were characterized on a quantitative level. This has afforded a detailed insight into the impact of the medium on the complexation reactions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. A Multi-responsive Regenerable Europium-Organic Framework Luminescent Sensor for Fe3+ , CrVI Anions, and Picric Acid.

    PubMed

    Liu, Wei; Huang, Xin; Xu, Cong; Chen, Chunyang; Yang, Lizi; Dou, Wei; Chen, Wanmin; Yang, Huan; Liu, Weisheng

    2016-12-23

    A novel luminescent microporous lanthanide metal-organic framework (Ln-MOF) based on a urea-containing ligand has been successfully assembled. Structural analysis revealed that the framework features two types of 1D channels, with urea N-H bonds projecting into the pores. Luminescence studies have revealed that the Ln-MOF exhibits high sensitivity, good selectivity, and a fast luminescence quenching response towards Fe 3+ , Cr VI anions, and picric acid. In particular, in the detection of Cr 2 O 7 2- and picric acid, the Ln-MOF can be simply and quickly regenerated, thus exhibiting excellent recyclability. To the best of our knowledge, this is the first example of a multi-responsive luminescent Ln-MOF sensor for Fe 3+ , Cr VI anions, and picric acid based on a urea derivative. This Ln-MOF may potentially be used as a multi-responsive regenerable luminescent sensor for the quantitative detection of toxic and harmful substances. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Toxic and signalling effects of oxalic acid

    PubMed Central

    Lehner, Arnaud; Meimoun, Patrice; Errakhi, Rafik; Madiona, Karine; Barakate, Mustapha

    2008-01-01

    Oxalic acid is thought to be a key factor of the early pathogenic stage in a wide range of necrotrophic fungi. We have recently published that oxalic acid induces Programmed Cell Death (PCD) in Arabidopsis thaliana cells. This cell death results from an early anionic efflux which is a prerequisite for the synthesis of ethylene and the PCD. Complementary experiments have been carried out by using seedlings of A. thaliana. The effects of millimolar concentrations of oxalic acid were analysed on A. thaliana seedlings. A treatment with a 3 mM oxalic acid solution does not alter the development of the plants but induces the transcription of defence related genes which are anion channel dependant. Moreover, our results suggest that a pre-treatment of the seedlings with oxalic acid is able to confer the resistance of A. thaliana against Sclerotium rolfsii. Regarding our results, we suggest that oxalic acid plays two distinct roles, depending on the concentration: a high concentration of oxalic acid induces a large PCD and then contribute to the progression of the fungi. However, at low concentration it is able to induce the establishment of a resistance of the plant against the fungi. PMID:19704845

  10. Gas-Phase Anionic σ-Adduct (Trans)formations in Heteroaromatic Systems1

    NASA Astrophysics Data System (ADS)

    Zimnicka, Magdalena; Danikiewicz, Witold

    2015-07-01

    Anions of nitroderivatives of thiophene and furan were subjected to the reactions with selected C-H acids in the gas phase. Various structures and reaction pathways were proposed for the observed ionic products. In general, the reactions of heteroaromatic anions with C-H acids may be divided into three groups, depending on the proton affinity difference between C-H acid's conjugate base and heteroaromatic anion (ΔPA). The proton transfer from C-H acid to heteroaromatic anion is a dominant process in the reactions for which ΔPA < 0 kcal mol-1, whereas the reactions with high ΔPA (ΔPA > 16 kcal mol-1) do not lead to any ionic products. The formation of σ-adducts and products of their further transformations according to the VNS, SNAr, cine, and tele substitution mechanisms have been proposed for reactions with moderate ΔPA. The other possible mechanisms as SN2 reaction, nucleophilic addition to the cyano group, ring-opening pathway, and halogenophilic reaction have also been discussed to contribute in the reactions between heteroaromatic anions and C-H acids.

  11. Dihydrogenphosphate recognition: Assistance from the acidic OH moiety of the anion

    NASA Astrophysics Data System (ADS)

    Das, Rituraj; Pathak, Nibedan; Choudhury, Samarjit; Borah, Suchibrata; Mahanta, Sanjeev Pran

    2017-11-01

    The binding affinity of the acidic hydrogen i.e. OH moiety of dihydrogenphosphate was investigated with receptors having competent H-bond donor and H-bond acceptor component. Three derivatives of 2, 3-dipyrrol-2‧-ylquinoxaline substituted with H-bond acceptor moiety at pyrrole α- positions were synthesized and their dihydrogenphosphate affinity was studied. All the three receptors shows general affinity towards fluoride, acetate and cyanide ions in DMSO solution. Interestingly, formyl substitution at both the pyrrole α-positions of 2, 3-dipyrrol-2‧-ylquinoxaline leads to binding of H2PO4-. 1H-NMR study rules out the involvement of the H-bond donor unit of the receptor in the biding event and reveals that the binding occurs predominantly via the Osbnd H⋯O interaction between the acidic OH moiety of the anion and the Cdbnd O of the formyl group of the receptor.

  12. Efficient in situ separation and production of L-lactic acid by Bacillus coagulans using weak basic anion-exchange resin.

    PubMed

    Zhang, Yitong; Qian, Zijun; Liu, Peng; Liu, Lei; Zheng, Zhaojuan; Ouyang, Jia

    2018-02-01

    To get rid of the dependence on lactic acid neutralizer, a simple and economical approach for efficient in situ separation and production of L-lactic acid was established by Bacillus coagulans using weak basic anion-exchange resin. During ten tested resins, the 335 weak basic anion-exchange resins demonstrated the highest adsorption capacity and selectivity for lactic acid recovery. The adsorption study of the 335 resins for lactic acid confirmed that it is an efficient adsorbent under fermentation condition. Langmuir models gave a good fit to the equilibrium data at 50 °C and the maximum adsorption capacity for lactic acid by 335 resins was about 402 mg/g. Adsorption kinetic experiments showed that pseudo-second-order kinetics model gave a good fit to the adsorption rate. When it was used for in situ fermentation, the yield of L-lactic acid by B. coagulans CC17 was close to traditional fermentation and still maintained at about 82% even after reuse by ten times. These results indicated that in situ separation and production of L-lactic acid using the 335 resins were efficient and feasible. This process could greatly reduce the dosage of neutralizing agent and potentially be used in industry.

  13. Capillary ion electrophoresis of inorganic anions and uric acid in human saliva using a polyvinyl alcohol coated capillary column and hexamethonium chloride as additive of background electrolyte.

    PubMed

    Mori, Masanobu; Yamamoto, Tsukasa; Kaseda, Maki; Yamada, Sachiko; Itabashi, Hideyuki

    2012-03-01

    A combination of polyvinyl alcohol chemically coated capillary (PVA capillary) and background electrolyte (BGE) with ion-pair reagent (hexamethonium dichloride, HMC) was used on capillary ion electrophoresis-UV detection (CIE-UV) for analysis of Br⁻, I⁻, NO₂⁻, NO₃⁻, SCN⁻ and uric acid in human saliva. The PVA capillary prepared in our laboratory minimized electro-osmotic flow (EOF) at the BGE in pH 3-10, and did not affect the UV detection at 210 nm by the PVA-layer on capillary wall. Therefore, use of the PVA capillary was suitable for sensitive UV detection for analyte anions, as well as suppression of protein adsorption. In this study, we optimized the BGE of 10 mM phosphate plus 10 mM HMC with applying a voltage of -15 kV. HMC as an additive to BGE could manipulate the electrophoretic mobility of anions, without electrostatic adsorption to the PVA capillary. The CIE-UV could separate and determine analyte anions in human saliva containing proteins by the direct injection without pretreatments such as dilution or deproteinization within 13 min. The relative standard deviations (n=10) were ranged of 0.5-1.6% in migration times, 2.2-6.8% in peak heights and 2.8-8.4% in peak areas. The limits of detection (S/N=3) were ranged of 3.42-6.87 μM. The peak height of anions in this system was gradually decreased through the successive injections of saliva samples, but the problem was successfully solved by periodically conditioning the PVA capillary. The quantifiability of anions in human saliva samples by the CIE-UV was evaluated through the recoveries by standard addition methods and comparison of other representative analytical methods, as well as identification by ion chromatography (IC). From the anion analyses in 12 different saliva samples, the CIE-UV demonstrated that can obtain obvious differences in concentrations of SCN⁻ between of smoker and non-smoker and those of uric acid between male and female with satisfactory results. Copyright

  14. Hydrophobic interactions between polymethacrylic acid and sodium laureth sulfate in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Yaremko, Z. M.; Fedushinskaya, L. B.; Burka, O. A.; Soltys, M. N.

    2014-09-01

    The role of hydrophobic interaction in the development of associative processes is demonstrated, based on the concentration dependences of the viscosity and pH of binary solutions of polymethacrylic acid as an anionic polyelectrolyte and sodium laureth sulfate as an anionic surfactant. It is found that the inflection point on the dependence of the difference between the pH values of binary solutions of polymethacrylic acid and sodium laureth sulfate on the polyelectrolyte concentration is a criterion for determining the predominant contribution from hydrophobic interaction, as is the inflection point on the dependence of pH of individual solutions of polymethacrylic acid on the polyelectrolyte concentration.

  15. Regeneration of strong-base anion-exchange resins by sequential chemical displacement

    DOEpatents

    Brown, Gilbert M.; Gu, Baohua; Moyer, Bruce A.; Bonnesen, Peter V.

    2002-01-01

    A method for regenerating strong-base anion exchange resins utilizing a sequential chemical displacement technique with new regenerant formulation. The new first regenerant solution is composed of a mixture of ferric chloride, a water-miscible organic solvent, hydrochloric acid, and water in which tetrachloroferrate anion is formed and used to displace the target anions on the resin. The second regenerant is composed of a dilute hydrochloric acid and is used to decompose tetrachloroferrate and elute ferric ions, thereby regenerating the resin. Alternative chemical displacement methods include: (1) displacement of target anions with fluoroborate followed by nitrate or salicylate and (2) displacement of target anions with salicylate followed by dilute hydrochloric acid. The methodology offers an improved regeneration efficiency, recovery, and waste minimization over the conventional displacement technique using sodium chloride (or a brine) or alkali metal hydroxide.

  16. Investigating the Weak to Evaluate the Strong: An Experimental Determination of the Electron Binding Energy of Carborane Anions and the Gas phase Acidity of Carborane Acids

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

    Meyer, Matthew M; Wang, Xue B; Reed, Christopher A

    2009-12-23

    Five CHB 11X 6Y 5 - carborane anions from the series X = Br, Cl, I and Y = H, Cl, CH 3 were generated by electrospray ionization, and their reactivity with a series of Brønsted acids and electron transfer reagents were examined in the gas phase. The undecachlorocarborane acid, H(CHB 11Cl 11), was found to be far more acidic than the former record holder, (1-C 4F 9SO 2) 2NH (i.e., ΔH° acid = 241 ± 29 vs 291.1 ± 2.2 kcal mol -1) and bridges the gas-phase acidity and basicity scales for the first time. Its conjugate base, CHBmore » 11Cl 11 -, was found by photoelectron spectroscopy to have a remarkably large electron binding energy (6.35 ± 0.02 eV) but the value for the (1-C 4F 9SO 2) 2N - anion is even larger (6.5 ± 0.1 eV). Consequently, it is the weak H-(CHB 11Cl 11) BDE (70.0 kcal mol -1, G3(MP2)) compared to the strong BDE of (1-C 4F 9SO 2) 2N-H (127.4 ± 3.2 kcal mol -1) that accounts for the greater acidity of carborane acids.« less

  17. Acid-base chemistry of dissolved organic matter in aqueous leaf extracts: Application to organic acids in throughfall. [Chrysolepis sempervirens; Pinus monticola; Salix orestera

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

    Brown, A.D.; Sposito, G.

    Elemental composition data were obtained for bulk precipitation and throughfall samples and for aqueous extracts of leaves of three woody plant species common in the subalpine Sierras Nevada range, California: chinquapin (Chrysolepis sempervirens Hjelmqvist), western white pine (Pinus monticola Dougl.), and willow (Salix orestera Schneider). The acid-base equilibria of the extracts were characterized by potentiometric titration and proton formation functions were computed. The latter then were modeled assuming four classes of quasiparticle acidic functional groups, yielding negative logarithms of conditional protonation constants in the range 4.8 to 5.0, 6.1 to 6.6, 7.4 to 7.7, and 9.1 to 9.4. The relativemore » concentration of a given acidic functional group class varied markedly among the three woody species, but the conditional protonation constants were very similar. The model parameters, along with dissolved organic C concentration and pH values, were used to estimate net anion deficits in throughfall samples collected from the same sites as the leaf samples. On average, the calculated charge concentration of free organic anions in the western white pine extract matched the throughfall anion deficit, whereas the deficits in the chinquapin and willow throughfall samples were not accounted for by free anion concentrations. Metal complexation and in situ, species-dependent leaf surfaces processes may account for these latter differences.« less

  18. A chloride-anion insensitive colorimetric chemosensor for trinitrobenzene and picric acid.

    PubMed

    Kim, Dae-Sik; Lynch, Vincent M; Nielsen, Kent A; Johnsen, Carsten; Jeppesen, Jan O; Sessler, Jonathan L

    2009-09-01

    A new receptor, the bisTTF-calix[2]thiophene[2]pyrrole derivative 3, has been prepared from the Lewis acid-catalyzed condensation of 2,5-bis(1-hydroxymethylethyl)thiopheno-TTF and pyrrole. This new system is found to form complexes with the electron-deficient guests, trinitrobenzene (TNB) and picric acid (PA), which serve as models for nitroaromatic explosives. The binding phenomenon, which has been studied in organic solution using proton nuclear magnetic resonance and absorption spectroscopies, results in an easy-to-visualize color change in chloroform that is independent of the presence of chloride anion, a known interferant for an earlier tetrakisTTF-calix[4]pyrrole TNB chemosensor. Support for the proposed binding mode comes from a preliminary solid state structure of the complex formed from TNB, namely TNB subset3. A color change is also observed when dichloromethane solutions of chemosensor 3 are added to solvent-free samples of TNB, PA, and 2,4,6-trinitrotoluene supported on silica gel.

  19. Separation of anionic oligosaccharides by high-performance liquid chromatography

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

    Green, E.D.; Baenziger, J.U.

    1986-10-01

    The authors have developed methods for rapid fractionation of anionic oligosaccharides containing sulfate and/or sialic acid moieties by high-performance liquid chromatography (HPLC). Ion-exchange HPLC on amine-bearing columns (Micropak AX-10 and AX-5) at pH 4.0 is utilized to separate anionic oligosaccharides bearing zero, one, two, three, or four charges, independent of the identity of the anionic moieties (sulfate and/or sialic acid). Ion-exchange HPLC at pH 1.7 allows separation of neutral, mono-, di-, and tetrasialylated, monosulfated, and disulfated oligosaccharides. Oligosaccharides containing three sialic acid residues and those bearing one each of sulfate and sialic acid, however, coelute at pH 1.7. Since themore » latter two oligosaccharide species separate at pH 4.0, analysis at pH 4.0 followed by analysis at pH 1.7 can be utilized to completely fractionate complex mixtures of sulfated and sialylated oligosaccharides. Ion-suppression amine adsorption HPLC has previously been shown to separate anionic oligosaccharides on the basis of net carbohydrate content (size). In this study they demonstrate the utility of ion-suppression amine adsorption HPLC for resolving sialylated oligosaccharide isomers which differ only in the linkages of sialic acid residues (..cap alpha..2,3 vs ..cap alpha..2,6) and/or location of ..cap alpha..2,3- and ..cap alpha..2,6-linked sialic acid moieties on the peripheral branches of oligosaccharides. These two methods can be used in tandem to separate oligosaccharides, both analytically and preparatively, based on their number, types, and linkages of anionic moieties.« less

  20. Increased anion gap metabolic acidosis as a result of 5-oxoproline (pyroglutamic acid): a role for acetaminophen.

    PubMed

    Fenves, Andrew Z; Kirkpatrick, Haskell M; Patel, Viralkumar V; Sweetman, Lawrence; Emmett, Michael

    2006-05-01

    The endogenous organic acid metabolic acidoses that occur commonly in adults include lactic acidosis; ketoacidosis; acidosis that results from the ingestion of toxic substances such as methanol, ethylene glycol, or paraldehyde; and a component of the acidosis of kidney failure. Another rare but underdiagnosed cause of severe, high anion gap metabolic acidosis in adults is that due to accumulation of 5-oxoproline (pyroglutamic acid). Reported are four patients with this syndrome, and reviewed are 18 adult patients who were reported previously in the literature. Twenty-one patients had major exposure to acetaminophen (one only acute exposure). Eighteen (82%) of the 22 patients were women. Most of the patients were malnourished as a result of multiple medical comorbidities, and most had some degree of kidney dysfunction or overt failure. The chronic ingestion of acetaminophen, especially by malnourished women, may generate high anion gap metabolic acidosis. This undoubtedly is an underdiagnosed condition because measurements of serum and/or urinary 5-oxoproline levels are not readily available.

  1. Adsorption behavior of benzenesulfonic acid by novel weakly basic anion exchange resins.

    PubMed

    Sun, Yue; Zuo, Peng; Luo, Junfen; Singh, Rajendra Prasad

    2017-04-01

    Two novel weakly basic anion exchange resins (SZ-1 and SZ-2) were prepared via the reaction of macroporous chloromethylated polystyrene-divinylbenzene (Cl-PS-DVB) beads with dicyclohexylamine and piperidine, respectively. The physicochemical structures of the resulting resins were characterized using Fourier Transform Infrared Spectroscopy and pore size distribution analysis. The adsorption behavior of SZ-1 and SZ-2 for benzenesulfonic acid (BA) was evaluated, and the common commercial weakly basic anion exchanger D301 was also employed for comparison purpose. Adsorption isotherms and influence of solution pH, temperature and coexisting competitive inorganic salts (Na 2 SO 4 and NaCl) on adsorption behavior were investigated and the optimum desorption agent was obtained. Adsorption isotherms of BA were found to be well represented by the Langmuir model. Thermodynamic parameters involving ΔH, ΔG and ΔS were also calculated and the results indicate that adsorption is an exothermic and spontaneous process. Enhanced selectivity of BA sorption over sulfate on the two novel resins was observed by comparison with the commercial anion exchanger D301. The fact that the tested resins loaded with BA can be efficiently regenerated by NaCl solution indicates the reversible sorption process. From a mechanistic viewpoint, this observation clearly suggests that electrostatic interaction is the predominant adsorption mechanism. Furthermore, results of column tests show that SZ-1 possesses a better adsorption property than D301, which reinforces the feasibility of SZ-1 for potential industrial application. Copyright © 2016. Published by Elsevier B.V.

  2. Evaluation of anionic surfactant concentrations in US effluents and probabilistic determination of their combined ecological risk in mixing zones.

    PubMed

    McDonough, Kathleen; Casteel, Kenneth; Itrich, Nina; Menzies, Jennifer; Belanger, Scott; Wehmeyer, Kenneth; Federle, Thomas

    2016-12-01

    Alcohol sulfates (AS), alcohol ethoxysulfates (AES), linear alkyl benzenesulfonates (LAS) and methyl ester sulfonates (MES) are anionic surfactants that are widely used in household detergents and consumer products resulting in over 1 million tons being disposed of down the drain annually in the US. A monitoring campaign was conducted which collected grab effluent samples from 44 wastewater treatment plants (WWTPs) across the US to generate statistical distributions of effluent concentrations for anionic surfactants. The mean concentrations for AS, AES, LAS and MES were 5.03±4.5, 1.95±0.7, 15.3±19, and 0.35±0.13μg/L respectively. Since each of these surfactants consist of multiple homologues that differ in their toxicity, the concentration of each homologue measured in an effluent sample was converted into a toxic unit (TU) by normalizing to the predicted no effect concentration (PNEC) derived from high tier effects data (mesocosm studies). The statistical distributions of the combined TUs in the effluents were used in combination with distributions of dilution factors for WWTP mixing zones to conduct a US-wide probabilistic risk assessment for the aquatic environment for each of the surfactants. The 90th percentile level of TUs for AS, AES, LAS and MES in mixing zones were 1.89×10 -2 , 2.73×10 -3 , 2.72×10 -2 , and 3.65×10 -5 under 7Q10 (lowest river flow occurring over a 7day period every 10years) low flow conditions. Because these surfactants have the same toxicological mode of action, the TUs were summed and the aquatic safety for anionic surfactants as a whole was assessed. At the 90th percentile level under the conservative 7Q10 low flow conditions the forecasted TUs were 4.21×10 -2 which indicates that there is a significant margin of safety for the class of anionic surfactants in US aquatic environments. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Comparison of 0.46% calcium diets with and without added anions with a 0.7% calcium anionic diet as a means to reduce periparturient hypocalcemia.

    PubMed

    Goff, Jesse P; Koszewski, Nicholas J

    2018-06-01

    .46 and 0.72% Ca anion diets, respectively. Precalving plasma PTH and 1,25-dihydroxyvitamin D concentrations were similar in cows fed the 0.46% Ca diets and the 0.72% Ca diets, suggesting that the 0.46% Ca diets were not low enough in Ca to place the cow in negative Ca balance before calving. In experiment 2, adding the anion supplements to a 2.05% K diet did not reduce urine pH below 8.0. Periparturient plasma Ca concentrations did not differ in cows in any group in experiment 2. Precalving diets that are 0.46% Ca fed ad libitum are too high in Ca to stimulate Ca homeostasis before calving. Adding anions to a diet can benefit periparturient cow plasma Ca concentration, but only if it alters acid-base status enough to reduce urine pH below 7.5. The Authors. Published by FASS Inc. and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

  4. Effect of pore structure on the removal of clofibric acid by magnetic anion exchange resin.

    PubMed

    Tan, Liang; Shuang, Chendong; Wang, Yunshu; Wang, Jun; Su, Yihong; Li, Aimin

    2018-01-01

    The effect of pore structure of resin on clofibric acid (CA) adsorption behavior was investigated by using magnetic anion exchange resins (ND-1, ND-2, ND-3) with increasing pore diameter by 11.68, 15.37, 24.94 nm. Resin with larger pores showed faster adsorption rates and a higher adsorption capacity because the more opened tunnels provided by larger pores benefit the CA diffusion into the resin matrix. The ion exchange by the electrostatic interactions between Cl-type resin and CA resulted in chloride releasing to the solution, and the ratio of released chloride to CA adsorption amount decreased from 0.90 to 0.65 for ND-1, ND-2 and ND-3, indicating that non-electrostatic interactions obtain a larger proportional part of the adsorption into the pores. Co-existing inorganic anions and organic acids reduced the CA adsorption amounts by the competition effect of electrostatic interaction, whereas resins with more opened pore structures weakened the negative influence on CA adsorption because of the existence of non-electrostatic interactions. 85.2% and 65.1% adsorption amounts decrease are calculated for resin ND-1 and ND-3 by the negative influence of 1 mmol L -1 NaCl. This weaken effect of organic acid is generally depends on its hydrophobicity (Log Kow) for carboxylic acid and its ionization degree (pKb) for sulfonic acid. The resins could be reused with the slightly decreases by 1.9%, 3.2% and 5.4% after 7 cycles of regeneration, respectively for ND-1, ND-2 and ND-3, suggesting the ion exchange resin with larger pores are against its reuse by the brine solution regeneration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Roles of organic anion transporters in the renal excretion of perfluorooctanoic acid.

    PubMed

    Nakagawa, Hatsuki; Hirata, Taku; Terada, Tomohiro; Jutabha, Promsuk; Miura, Daisaku; Harada, Kouji H; Inoue, Kayoko; Anzai, Naohiko; Endou, Hitoshi; Inui, Ken-Ichi; Kanai, Yoshikatsu; Koizumi, Akio

    2008-07-01

    Perfluorooctanoic acid, an environmental contaminant, is found in both wild animals and human beings. There are large species and sex differences in the renal excretion of perfluorooctanoic acid. In the present study, we aimed to characterize organic anion transporters 1-3 (OAT1-3) in human beings and rats to investigate whether the species differences in the elimination kinetics of perfluorooctanoic acid from the kidneys can be attributed to differences in the affinities of these transporters for perfluorooctanoic acid. We used human (h) and rat (r) OAT transient expression cell systems and measured the [(14)C] perfluorooctanoic acid transport activities. Both human and rat OAT1 and OAT3 mediated perfluorooctanoic acid transport to similar degrees. Specifically, the kinetic parameters, K(m), were 48.0 +/- 6.4 microM for h OAT1; 51.0 +/- 12.0 microM for rOAT1; 49.1 +/- 21.4 microM for hOAT3 and 80.2 +/- 17.8 microM for rOAT3, respectively. These data indicate that both human and rat OAT1 and OAT3 have high affinities for perfluorooctanoic acid and that the species differences in its renal elimination are not attributable to affinity differences in these OATs between human beings and rats. In contrast, neither hOAT2 nor rOAT2 transported perfluorooctanoic acid. In conclusion, OAT1 and OAT3 mediated perfluorooctanoic acid transport in vitro, suggesting that these transporters also transport perfluorooctanoic acid through the basolateral membrane of proximal tubular cells in vivo in both human beings and rats. Neither human nor rat OAT2 mediated perfluorooctanoic acid transport. Collectively, the difference between the perfluorooctanoic acid half-lives in human beings and rats is not likely to be attributable to differences in the affinities of these transporters for perfluorooctanoic acid.

  6. Expression pattern of the type 1 sigma receptor in the brain and identity of critical anionic amino acid residues in the ligand-binding domain of the receptor.

    PubMed

    Seth, P; Ganapathy, M E; Conway, S J; Bridges, C D; Smith, S B; Casellas, P; Ganapathy, V

    2001-07-25

    The type 1 sigma receptor (sigmaR1) has been shown to participate in a variety of functions in the central nervous system. To identify the specific regions of the brain that are involved in sigmaR1 function, we analyzed the expression pattern of the receptor mRNA in the mouse brain by in situ hybridization. SigmaR1 mRNA was detectable primarily in the cerebral cortex, hippocampus, and Purkinje cells of cerebellum. To identify the critical anionic amino acid residues in the ligand-binding domain of sigmaR1, we employed two different approaches: chemical modification of anionic amino acid residues and site-directed mutagenesis. Chemical modification of anionic amino acids in sigmaR1 with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide reduced the ligand-binding activity markedly. Since it is known that a splice variant of this receptor which lacks exon 3 does not have the ability to bind sigma ligands, the ligand-binding domain with its critical anionic amino acid residues is likely to be present in or around the region coded by exon 3. Therefore, each of the anionic amino acids in this region was mutated individually and the influence of each mutation on ligand binding was assessed. These studies have identified two anionic amino acids, D126 and E172, that are obligatory for ligand binding. Even though the ligand-binding function was abolished by these two mutations, the expression of these mutants was normal at the protein level. These results show that sigmaR1 is expressed at high levels in specific areas of the brain that are involved in memory, emotion and motor functions. The results also provide important information on the chemical nature of the ligand-binding site of sigmaR1 that may be of use in the design of sigmaR1-specific ligands with potential for modulation of sigmaR1-related brain functions.

  7. Anion photoelectron spectroscopy of acid-base systems, solvated molecules and MALDI matrix molecules

    NASA Astrophysics Data System (ADS)

    Eustis, Soren Newman

    Gas phase, mass-selected, anion photoelectron spectroscopic studies were performed on a variety of molecular systems. These studies can be grouped into three main themes: acid-base interactions, solvation, and ions of analytical interest. Acid-base interactions represent some of the most fundamental processes in chemistry. The study of these processes elucidates elementary principles such as inner and outer sphere complexes, hard and soft ions, and salt formation---to name a few. Apart from their appeal from a pedagogical standpoint, the ubiquity of chemical reactions which involve acids, bases or the resulting salts makes the study of their fundamental interactions both necessary and fruitful. With this in mind, the neutral and anionic series (NH3···HX) (X= F, Cl, Br, I) were examined experimentally and theoretically. The relatively small size of these systems, combined with the advances in computational methods, allowed our experimental results to be compared with very high level ab initio theoretical results. The synergy between theory and experiment yielded an understanding of the nature of the complexes that could not be achieved with either method in isolation. The second theme present in this body or work is molecular solvation. Solvation is a phenomenon which is present in biology, chemistry and physics. Many biological molecules do not become 'active' until they are solvated by water. Thus, the study of biologically relevant species solvated by water is one step in a bottom up approach to studying the biochemical interactions in living organisms. Furthermore, the hydration of acidic molecules in the atmosphere is what drives the formation of 'free' protons or hydronium ions which are the key players in acid driven chemistry. Here are presented two unique solvation studies, Adenine(H2O)-n and C6F6(H2O)-n, these systems are very distinct, but show somewhat similar responses to hydration. The last theme presented in this work is the electronic properties

  8. An anionic rhodium eta4-quinonoid complex as a multifunctional catalyst for the arylation of aldehydes with arylboronic acids.

    PubMed

    Son, Seung Uk; Kim, Sang Bok; Reingold, Jeffrey A; Carpenter, Gene B; Sweigart, Dwight A

    2005-09-07

    The pi-bonded rhodium quinonoid complex, K+[(1,4-benzoquinone)Rh(COD)]-, functions as a good catalyst for the coupling of arylboronic acid and aldehydes to afford diaryl alcohols. The catalysis is heterobimetallic in that both the transition metal and concomitant alkali metal counterion play an integral part in the reaction. In addition, the anionic quinonoid catalyst itself plays a bifunctional role by acting as a ligand to the boronic acid and as a Lewis acid receptor site for the transferring aryl group.

  9. Chaotropic Monovalent Anion-Induced Rectification Inversion at Nanopipettes Modified by Polyimidazolium Brushes.

    PubMed

    He, Xiulan; Zhang, Kailin; Liu, Yang; Wu, Fei; Yu, Ping; Mao, Lanqun

    2018-04-16

    A nonintuitive observation of monovalent anion-induced ion current rectification inversion at polyimidazolium brush (PimB)-modified nanopipettes is presented. The rectification inversion degree is strongly dependent on the concentration and species of monovalent anions. For chaotropic anions (for example, ClO 4 - ), the rectification inversion is easily observed at a low concentration (5 mm), while there is no rectification inversion observed for kosmotropic anions (Cl - ) even at a high concentration (1 m). Moreover, at the specific concentration (for example, 10 mm), the variation of rectification ratio on the type of anions is ranged by Hofmeister series (Cl - ≥NO 3 - >BF 4 - >ClO 4 - >PF 6 - >Tf 2 N - ). Estimation of the electrokinetic charge density (σ ek ) demonstrates that rectification inversion originates from the charge inversion owing to the over-adsorption of chaotropic monovalent anion. To qualitatively understand this phenomenon, a concentration-dependent adsorption mechanism is proposed. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. [5-0xoproline (pyroglutamic acid) acidosis and acetaminophen- a differential diagnosis in high anion gap metabolic acidosis].

    PubMed

    Weiler, Stefan; Bellmann, Romuald; Kullak-Ublick, Gerd A

    2015-12-01

    Rare cases of high anion gap metabolic acidosis during long-term paracetamol administration in therapeutic doses with causative 5-oxoproline (pyroglutamic acid} accumulation have been reported. Other concomitant risk factors such as malnutrition, alcohol abuse, renal or hepatic dysfunction, comedication with flue/oxacillin, vigabatrin, netilmicin or sepsis have been described. The etiology seems to be a drug-induced reversible inhibition of glutathione synthetase or 5-oxoprolinase leading to elevated serum and urine levels of 5-oxoproline. Other more frequent differential diagnoses, such as intoxications, ketoacidosis or lactic acidosis should be excluded. Causative substances should be stopped. 5-oxoproline concentrations in urine can be quantified to establish the diagnosis. Adverse drug reactions, which are not listed or insufficiently described in the respective Swiss product information, should be reported to the regional pharmacovigilance centres for early signal detection. 5-0 xoproline acidosis will be integrated as a potential adverse drug reaction in the Swiss product information for paracetamol.

  11. A novel multi-hyphenated analytical method to simultaneously determine xanthine oxidase inhibitors and superoxide anion scavengers in natural products.

    PubMed

    Qi, Jin; Sun, Li-Qiong; Qian, Steven Y; Yu, Bo-Yang

    2017-09-01

    Natural products, such as rosmarinic acid and apigenin, can act as xanthine oxidase inhibitors (XOIs) as well as superoxide anion scavengers, and have potential for treatment of diseases associated with high uric acid levels and oxidative stress. However, efficient simultaneous screening of these two bioactivities in natural products has been challenging. We have developed a novel method by assembling a multi-hyphenated high performance liquid chromatography (HPLC) system that combines a photo-diode array, chemiluminescence detector and a HPLC system with a variable wavelength detector, to simultaneously detect components that act as both XOIs and superoxide anion scavengers in natural products. Superoxide anion scavenging activity in the analyte was measured by on-line chemiluminescence chromatography based on pyrogallol-luminol oxidation, while xanthine oxidase inhibitory activity was determined by semi-on-line HPLC analysis. After optimizing multiple elements, including chromatographic conditions (e.g., organic solvent concentration and mobile phase pH), concentrations of xanthine/xanthine oxidase and reaction temperature, our validated analytical method was capable of mixed sample analysis. The final results from our method are presented in an easily understood visual format including comprehensive bioactivity data of natural products. Copyright © 2017. Published by Elsevier B.V.

  12. Modelling of Batch Lactic Acid Fermentation in
the Presence of Anionic Clay

    PubMed Central

    Jinescu, Cosmin; Aruş, Vasilica Alisa; Nistor, Ileana Denisa

    2014-01-01

    Summary Batch fermentation of milk inoculated with lactic acid bacteria was conducted in the presence of hydrotalcite-type anionic clay under static and ultrasonic conditions. An experimental study of the effect of fermentation temperature (t=38–43 °C), clay/milk ratio (R=1–7.5 g/L) and ultrasonic field (ν=0 and 35 kHz) on process dynamics was performed. A mathematical model was selected to describe the fermentation process kinetics and its parameters were estimated based on experimental data. A good agreement between the experimental and simulated results was achieved. Consequently, the model can be employed to predict the dynamics of batch lactic acid fermentation with values of process variables in the studied ranges. A statistical analysis of the data based on a 23 factorial experiment was performed in order to express experimental and model-regressed process responses depending on t, R and ν factors. PMID:27904318

  13. Determination of Inorganic Cations and Anions in Chitooligosaccharides by Ion Chromatography with Conductivity Detection.

    PubMed

    Cao, Lidong; Li, Xiuhuan; Fan, Li; Zheng, Li; Wu, Miaomiao; Zhang, Shanxue; Huang, Qiliang

    2017-02-22

    Chitooligosaccharides (COSs) are a promising drug candidate and food ingredient because they are innately biocompatible, non-toxic, and non-allergenic to living tissues. Therefore, the impurities in COSs must be clearly elucidated and precisely determined. As for COSs, most analytical methods focus on the determination of the average degrees of polymerization (DPs) and deacetylation (DD), as well as separation and analysis of the single COSs with different DPs. However, little is known about the concentrations of inorganic cations and anions in COSs. In the present study, an efficient and sensitive ion chromatography coupled with conductivity detection (IC-CD) for the determination of inorganic cations Na⁺, NH₄⁺, K⁺, Mg 2+ , Ca 2+ , and chloride, acetate and lactate anions was developed. Detection limits were 0.01-0.05 μM for cations and 0.5-0.6 μM for anions. The linear range was 0.001-0.8 mM. The optimized analysis was carried out on IonPac CS12A and IonPac AS12A analytical column for cations and anions, respectively, using isocratic elution with 20 mM methanesulfonic acid and 4 mM sodium hydroxide aqueous solution as the mobile phase at a 1.0 mL/min flow rate. Quality parameters, including precision and accuracy, were fully validated and found to be satisfactory. The fully validated IC-CD method was readily applied for the quantification of various cations and anions in commercial COS technical concentrate.

  14. Determination of Inorganic Cations and Anions in Chitooligosaccharides by Ion Chromatography with Conductivity Detection

    PubMed Central

    Cao, Lidong; Li, Xiuhuan; Fan, Li; Zheng, Li; Wu, Miaomiao; Zhang, Shanxue; Huang, Qiliang

    2017-01-01

    Chitooligosaccharides (COSs) are a promising drug candidate and food ingredient because they are innately biocompatible, non-toxic, and non-allergenic to living tissues. Therefore, the impurities in COSs must be clearly elucidated and precisely determined. As for COSs, most analytical methods focus on the determination of the average degrees of polymerization (DPs) and deacetylation (DD), as well as separation and analysis of the single COSs with different DPs. However, little is known about the concentrations of inorganic cations and anions in COSs. In the present study, an efficient and sensitive ion chromatography coupled with conductivity detection (IC-CD) for the determination of inorganic cations Na+, NH4+, K+, Mg2+, Ca2+, and chloride, acetate and lactate anions was developed. Detection limits were 0.01–0.05 μM for cations and 0.5–0.6 μM for anions. The linear range was 0.001–0.8 mM. The optimized analysis was carried out on IonPac CS12A and IonPac AS12A analytical column for cations and anions, respectively, using isocratic elution with 20 mM methanesulfonic acid and 4 mM sodium hydroxide aqueous solution as the mobile phase at a 1.0 mL/min flow rate. Quality parameters, including precision and accuracy, were fully validated and found to be satisfactory. The fully validated IC-CD method was readily applied for the quantification of various cations and anions in commercial COS technical concentrate. PMID:28241416

  15. Acid rain effects on aluminum mobilization clarified by inclusion of strong organic acids.

    PubMed

    Lawrence, G B; Sutherland, J W; Boylen, C W; Nierzwicki-Bauer, S W; Momen, B; Baldigo, B P; Simonin, H A

    2007-01-01

    Assessments of acidic deposition effects on aquatic ecosystems have often been hindered by complications from naturally occurring organic acidity. Measurements of pH and ANCG, the most commonly used indicators of chemical effects, can be substantially influenced by the presence of organic acids. Relationships between pH and inorganic Al, which is toxic to many forms of aquatic biota, are also altered by organic acids. However, when inorganic Al concentrations are plotted against ANC (the sum of Ca2+, Mg2+, Na+, and K+, minus S042-, N03-, and Cl-), a distinct threshold for Al mobilization becomes apparent. If the concentration of strong organic anions is included as a negative component of ANC, the threshold occurs at an ANC value of approximately zero, the value expected from theoretical charge balance constraints. This adjusted ANC is termed the base-cation surplus. The threshold relationship between the base-cation surplus and Al was shown with data from approximately 200 streams in the Adirondack region of New York, during periods with low and high dissolved organic carbon concentrations, and for an additional stream from the Catskill region of New York. These results indicate that (1) strong organic anions can contribute to the mobilization of inorganic Al in combination with SO42- and N03-, and (2) the presence of inorganic Al in surface waters is an unambiguous indication of acidic deposition effects.

  16. Extraction of acidic degradation products of organophosphorus chemical warfare agents. Comparison between silica and mixed-mode strong anion-exchange cartridges.

    PubMed

    Kanaujia, Pankaj K; Pardasani, Deepak; Gupta, A K; Kumar, Rajesh; Srivastava, R K; Dubey, D K

    2007-08-17

    The analysis of alkyl alkylphosphonic acids (AAPAs) and alkylphosphonic acids (APAs), the hydrolyzed products of nerve agents, constitutes an important aspect for verifying the compliance to the Chemical weapons convention (CWC). This work devotes on the development of solid-phase extraction method using polymeric mixed-mode strong anion-exchange (Oasis MAX) cartridges for extraction of AAPAs and APAs from water. The extracted analytes were analyzed by GC-MS under full scan and selected ion monitoring mode. The extraction efficiencies of MAX and silica-based anion-exchange cartridges were compared, and results revealed that MAX sorbents yielded better recoveries. Extraction parameters, such as loading capacity, extraction solvent, its volume, and washing solvent were optimized. Best recoveries were obtained using 1 mL of acidic methanol (0.1 M), and limits of detection could be achieved up to 5 x 10(-4) microg mL(-1) (in SIM) and 0.05 microg mL(-1) in full scan mode. The method was successfully employed for the detection and identification of alkylphosphonic acids present in soil sample sent by the Organization for Prohibition of Chemical Weapons (OPCW) in the official proficiency tests.

  17. Anion-exchange high-performance liquid chromatography with post-column detection for the analysis of phytic acid and other inositol phosphates

    NASA Technical Reports Server (NTRS)

    Rounds, M. A.; Nielsen, S. S.; Mitchell, C. A. (Principal Investigator)

    1993-01-01

    The use of gradient anion-exchange HPLC, with a simple post-column detection system, is described for the separation of myo-inositol phosphates, including "phytic acid" (myo-inositol hexaphosphate). Hexa-, penta-, tetra-, tri- and diphosphate members of this homologous series are clearly resolved within 30 min. This method should facilitate analysis and quantitation of "phytic acid" and other inositol phosphates in plant, food, and soil samples.

  18. Concentration-Discharge Relationships, Nested Reaction Fronts, and the Balance of Oxidative and Acid-Base Weathering Fluxes in an Alpine Catchment, East River, Colorado

    NASA Astrophysics Data System (ADS)

    Winnick, M.; Carroll, R. W. H.; Williams, K. H.; Maxwell, R. M.; Maher, K.

    2016-12-01

    Although important for solute production and transport, the varied interactions between biogeochemical processes and subsurface hydrology remain poorly characterized. We investigate these couplings in the headwaters of the East River, CO, a high-elevation shale-dominated catchment system in the Rocky Mountains, using concentration-discharge (C-Q) relationships for major cations, anions, and organic carbon. Dissolved organic carbon (DOC) displays a positive C-Q relationship with well-defined clockwise hysteresis, indicating the mobilization and depletion of DOC in the upper soil horizons and highlighting the importance of shallow flowpaths through the snowmelt period. Cation and anion concentrations demonstrate that carbonate weathering, which dominates solute fluxes, is promoted by both carbonic acid and sulfuric acid derived from oxidation of pyrite in the shale bedrock. Sulfuric acid weathering in the deep subsurface dominates during base flow conditions when waters have infiltrated below the hypothesized pyrite oxidation front, whereas carbonic acid weathering plays a dominant role during the snowmelt period as a result of shallow flowpaths. Differential C-Q relationships between solutes suggest that infiltrating waters approach calcite saturation before reaching the pyrite oxidation front, after which sulfuric acid reduces carbonate alkalinity. This increase in CO2(aq) at the expense of HCO3- results in outgassing of CO2 when waters equilibrate to surface conditions, and reduces the export of carbon and alkalinity from the East River by roughly 33% annually. Future changes in snowmelt dynamics that control the balance of carbonic and sulfuric acid weathering therefore have the capacity to substantially alter the cycling of carbon in the East River catchment. Ultimately, we demonstrate that differential C-Q relationships between major solutes can provide unique insights into the complex subsurface flow and biogeochemical dynamics that operate at catchment scales.

  19. Functionalized UO[sub 2] salenes. Neutral receptors for anions

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

    Rudkevich, D.M.; Verboom, W.; Brzozka, Z.

    1994-05-18

    A novel class of neutral receptors for anions that contain a unique combination of an immobilized Lewis acidic binding site (UO[sub 2][sup 2+]) and additional amide C(O)NH groups, which can form a favorable H-bond with a coordinated anion guest, has been developed. The unique combination of a Lewis acidic UO[sub 2] center and amide C(O)NH groups in one receptor leads to highly specific H[sub 2]PO[sub 4[sup [minus

  20. Experimentally quantifying anion polarizability at the air/water interface.

    PubMed

    Tong, Yujin; Zhang, Igor Ying; Campen, R Kramer

    2018-04-03

    The adsorption of large, polarizable anions from aqueous solution on the air/water interface controls important atmospheric chemistry and is thought to resemble anion adsorption at hydrophobic interfaces generally. While the favourability of adsorption of such ions is clear, quantifying adsorption thermodynamics has proven challenging because it requires accurate description of the structure of the anion and its solvation shell at the interface. In principle anion polarizability offers a structural window, but to the best of our knowledge there has so far been no experimental technique that allowed its characterization with interfacial specificity. Here, we meet this challenge using interface-specific vibrational spectroscopy of Cl-O vibrations of the [Formula: see text] anion at the air/water interface and report that the interface breaks the symmetry of the anion, the anisotropy of [Formula: see text]'s polarizability tensor is more than two times larger than in bulk water and concentration dependent, and concentration-dependent polarizability changes are consistent with correlated changes in surface tension.

  1. THE KINETICS OF SAPONIFICATION OF IODOACETIC ACID BY SODIUM HYDROXIDE AND BY CERTAIN ALKALINE BUFFER SOLUTIONS.

    PubMed

    Brdicka, R

    1936-07-20

    1. The rate of the saponification of iodoacetic acid in sodium hydroxide and alkaline buffer solutions yielding glycollic acid was measured by means of Heyrovský's polarographic method. 2. From the bimolecular velocity constants, increasing with the ionic strength of the solution, the Brönsted factor, F, which characterizes the primary salt effect, was calculated. 3. In the borate buffer solutions the monomolecular constants of the saponification were determined which, at values above the pH of neutralization of boric acid, show a proportionality to the concentration of hydroxyl anions. Below the pH of neutralization of boric acid, they are proportional to the concentration of borate anions.

  2. Ion-exchange equilibrium of N-acetyl-D-neuraminic acid on a strong anionic exchanger.

    PubMed

    Wu, Jinglan; Ke, Xu; Zhang, Xudong; Zhuang, Wei; Zhou, Jingwei; Ying, Hanjie

    2015-09-15

    N-acetyl-D-neuraminic acid (Neu5Ac) is a high value-added product widely applied in the food industry. A suitable equilibrium model is required for purification of Neu5Ac based on ion-exchange chromatography. Hence, the equilibrium uptake of Neu5Ac on a strong anion exchanger, AD-1 was investigated experimentally and theoretically. The uptake of Neu5Ac by the hydroxyl form of the resin occurred primarily by a stoichiometric exchange of Neu5Ac(-) and OH(-). The experimental data showed that the selectivity coefficient for the exchange of Neu5Ac(-) with OH(-) was a non-constant quantity. Subsequently, the Saunders' model, which took into account the dissociation reactions of Neu5Ac and the condition of electroneutrality, was used to correlate the Neu5Ac sorption isotherms at various solution pHs and Neu5Ac concentrations. The model provided an excellent fit to the binary exchange data for Cl(-)/OH(-) and Neu5Ac(-)/OH(-), and an approximate prediction of equilibrium in the ternary system Cl(-)/Neu5Ac(-)/OH(-). This basic information combined with the general mass transfer model could lay the foundation for the prediction of dynamic behavior of fixed bed separation process afterwards. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Acid rain effects on aluminum mobilization clarified by inclusion of strong organic acids

    USGS Publications Warehouse

    Lawrence, G.B.; Sutherland, J.W.; Boylen, C.W.; Nierzwicki-Bauer, S. W.; Momen, B.; Baldigo, Barry P.; Simonin, H.A.

    2007-01-01

    Assessments of acidic deposition effects on aquatic ecosystems have often been hindered by complications from naturally occurring organic acidity. Measurements of pH and ANCG, the most commonly used indicators of chemical effects, can be substantially influenced by the presence of organic acids. Relationships between pH and inorganic Al, which is toxic to many forms of aquatic biota, are also altered by organic acids. However, when inorganic Al concentrations are plotted against ANC (the sum of Ca2+, Mg 2+, Na+, and K+, minus SO42-, NO3-, and Cl-), a distinct threshold for Al mobilization becomes apparent. If the concentration of strong organic anions is included as a negative component of ANC, the threshold occurs at an ANC value of approximately zero, the value expected from theoretical charge balance constraints. This adjusted ANC is termed the base-cation surplus. The threshold relationship between the base-cation surplus and Al was shown with data from approximately 200 streams in the Adirondack region of New York, during periods with low and high dissolved organic carbon concentrations, and for an additional stream from the Catskill region of New York. These results indicate that (1) strong organic anions can contribute to the mobilization of inorganic Al in combination with SO42- and NO 3-, and (2) the presence of inorganic Al in surface waters is an unambiguous indication of acidic deposition effects. ?? 2007 American Chemical Society.

  4. Concentration and purification of plutonium or thorium

    DOEpatents

    Hayden, John A.; Plock, Carl E.

    1976-01-01

    In this invention a first solution obtained from such as a plutonium/thorium purification process or the like, containing plutonium (Pu) and/or thorium (Th) in such as a low nitric acid (HNO.sub.3) concentration may have the Pu and/or Th separated and concentrated by passing an electrical current from a first solution having disposed therein an anode to a second solution having disposed therein a cathode and separated from the first solution by a cation permeable membrane, the Pu or Th cation permeating the cation membrane and forming an anionic complex within the second solution, and electrical current passage affecting the complex formed to permeate an anion membrane separating the second solution from an adjoining third solution containing disposed therein an anode, thereby effecting separation and concentration of the Pu and/or Th in the third solution.

  5. Recovery of boric acid from ion exchangers

    DOEpatents

    Pollock, Charles W.

    1976-01-01

    The recovery of boric acid from an anion exchange resin is improved by eluting the boric acid with an aqueous solution of ammonium bicarbonate. The boric acid can be readily purified and concentrated by distilling off the water and ammonium bicarbonate. This process is especially useful for the recovery of boric acid containing a high percentage of .sup.10 B which may be found in some nuclear reactor coolant solutions.

  6. Donnan membrane technique (DMT) for anion measurement.

    PubMed

    Vega, Flora Alonso; Weng, Liping; Temminghoff, Erwin J M; Van Riemsdijk, Willem H

    2010-04-01

    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 NO(3)(-), 1-4 days for SO(4)(2-) and SeO(4)(2-), and 1-14 days for H(2)PO(4)(-) in a background of 2-200 mM KCl or K(2)SO(4). The strongest effect of ionic strength on equilibrium time is found for H(2)PO(4)(-), followed by SO(4)(2-) and SeO(4)(2-), and then by Cl(-) and NO(3)(-). The negatively charged organic particles of fulvic and humic acids do not pass the membrane. Two approaches for the measurement of different anion species of the same element, such as SeO(4)(2-) and HSeO(3)(-), using DMT are proposed and tested. These two approaches are based on transport kinetics or response to ionic strength difference. A transport model that was developed previously for cation DMT is applied in this work to analyze the rate-limiting step in the anion DMT. In the absence of mobile/labile complexes, transport tends to be controlled by diffusion in solution at a low ionic strength, whereas at a higher ionic strength, diffusion in the membrane starts to control the transport.

  7. Bond Dissociation Free Energies (BDFEs) of the Acidic H-A Bonds in HA(*)(-) Radical Anions by Three Different Pathways.

    PubMed

    Zhao, Yongyu; Bordwell, Frederick G.

    1996-09-20

    Cleavage of radical anions, HA(*)(-), have been considered to give either H(*) + A(-) (path a) or H(-) + A(*) (path b), and factors determining the preferred mode of cleavage have been discussed. It is conceivable that cleavage to give a proton and a radical dianion, HA(*)(-) right harpoon over left harpoon H(+) + A(*)(2)(-) (path c), might also be feasible. A method, based on a thermodynamic cycle, to estimate the bond dissociation free energy (BDFE) by path c has been devised. Comparison of the BDFEs for cleavage of the radical anions derived from 24 nitroaromatic OH, SH, NH, and CH acids by paths a, b, c has shown that path c is favored thermodynamically.

  8. Intercalation of p-methycinnamic acid anion into Zn-Al layered double hydroxide to improve UV aging resistance of asphalt

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

    Peng, Chao; State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070; Dai, Jing

    2015-02-15

    A UV absorber, p-methycinnamic acid (PMCA), was intercalated into Zn-Al layered double hydroxide (LDH) by calcination recovery. Fourier transform infrared spectroscopy showed that the PMCA anions completely replaced the CO{sub 3}{sup 2−} anions in the interlayer galleries of Zn-Al-LDH containing PMCA anions (Zn-Al-PMCA-LDH). X-ray diffraction and transmission electron microscopy showed that the interlayer distance increased from 0.78 nm to 1.82 nm after the substitution of PMCA anions for CO{sub 3}{sup 2−} anions. The similar diffraction angles of the CO{sub 3}{sup 2−} anion-containing Zn-Al-LDH (Zn-Al-CO{sub 3}{sup 2−}-LDH) and the Zn-Al-CO{sub 3}{sup 2−}-LDH/styrene–butadiene–styrene (SBS) modified asphalt implied that the asphalt molecules domore » not enter into the LDH interlayer galleries to form separated-phase structures. The different diffraction angles of Zn-Al-PMCA-LDH and Zn-Al-PMCA-LDH/SBS modified asphalt indicated that the asphalt molecules penetrated into the LDH interlayer galleries to form an expanded-phase structure. UV-Vis absorbance analyses showed that Zn-Al-PMCA-LDH was better able to block UV light due to the synergistic effects of PMCA and Zn-Al-LDH. Conventional physical tests and atomic force microscopy images of the SBS modified asphalt, Zn-Al-CO{sub 3}{sup 2−}-LDH/SBS modified asphalt and Zn-Al-PMCA-LDH/SBS modified asphalt before and after UV aging indicated that Zn-Al-PMCA-LDH improved the UV aging resistance of SBS modified asphalts.« less

  9. THE KINETICS OF SAPONIFICATION OF IODOACETIC ACID BY SODIUM HYDROXIDE AND BY CERTAIN ALKALINE BUFFER SOLUTIONS

    PubMed Central

    Brdička, R.

    1936-01-01

    1. The rate of the saponification of iodoacetic acid in sodium hydroxide and alkaline buffer solutions yielding glycollic acid was measured by means of Heyrovský's polarographic method. 2. From the bimolecular velocity constants, increasing with the ionic strength of the solution, the Brönsted factor, F, which characterizes the primary salt effect, was calculated. 3. In the borate buffer solutions the monomolecular constants of the saponification were determined which, at values above the pH of neutralization of boric acid, show a proportionality to the concentration of hydroxyl anions. Below the pH of neutralization of boric acid, they are proportional to the concentration of borate anions. PMID:19872968

  10. A delicate case of unidirectional proton transfer from water to an aromatic heterocyclic anion.

    PubMed

    Biswas, Sohag; Mallik, Bhabani S

    2016-11-21

    We present the characteristic proton transfer process from water to the pyrazole anion, infrared signatures of hydroxyl groups and the free energy profile of the process in aqueous solution combining first principles simulations, wavelet analysis and metadynamics. Our results show that the presence of minimum three water molecules in the gas phase cluster with a particular arrangement is sufficient to facilitate the proton transfer process from water to the anion. The overall reaction is very rapid in aqueous solution, and the free energy barrier for this process is found to be 4.2 kcal mol -1 . One of the earlier reported fundamental reasons for the transfer of proton from water to the anion is the change in the acidity of OH groups surrounding the anion. We have correlated the stretching frequencies of the surrounding OH groups with this acidity. We find that the development of less energetic vibrational states, and the OH mode having lowest average stretching frequency contains the most acidic proton. A large frequency shift of the OH mode belonging to one of the surrounding water molecules is observed during the transfer of proton from water to the anion; this shift is due to the change in acidity of the adjacent hydroxyl groups in the vicinity of the anion.

  11. Sample stacking of fast-moving anions in capillary zone electrophoresis with pH-suppressed electroosmotic flow.

    PubMed

    Quirino, J P; Terabe, S

    1999-07-30

    On-line sample concentration of fast moving inorganic anions by large volume sample stacking (LVSS) and field enhanced sample injection (FESI) with a water plug under acidic conditions is presented. Detection sensitivity enhancements were around 100 and 1000-fold for LVSS and FESI, respectively. However, reproducibility and linearity of response in the LVSS approach is superior compared to the FESI approach.

  12. Impact of glycolate anion on aqueous corrosion in DWPF and downstream facilities

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

    Mickalonis, J. I.

    2015-12-15

    Glycolic acid is being evaluated as an alternate reductant in the preparation of high level waste for the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). During processing, the glycolic acid may not be completely consumed with small quantities of the glycolate anion being carried forward to other high level waste (HLW) facilities. The impact of the glycolate anion on the corrosion of the materials of construction (MoC) throughout the waste processing system has not been previously evaluated. A literature review had revealed that corrosion data were not available for the MoCs in glycolic-bearing solutions applicable tomore » SRS systems. Data on the material compatibility with only glycolic acid or its derivative products were identified; however, data were limited for solutions containing glycolic acid or the glycolate anion.« less

  13. Amino acid anions in organic ionic compounds. An ab initio study of selected ion pairs.

    PubMed

    Benedetto, A; Bodo, E; Gontrani, L; Ballone, P; Caminiti, R

    2014-03-06

    The combination of amino acids in their deprotonated and thus anionic form with a choline cation gives origin to a new and potentially important class of organic ionic compounds. A series of such neutral ion pairs has been investigated by first principle methods. The results reveal intriguing structural motives as well as regular patterns in the charge distribution and predict a number of vibrational and optical properties that could guide the experimental investigation of these compounds. The replacement of choline with its phosphocholine analogue causes the spontaneous reciprocal neutralization of cations and anions, taking place through the transfer of a proton between the two ions. Systems of this kind, therefore, provide a wide and easily accessible playground to probe the ionic/polar transition in organic systems, while the easy transfer of H(+) among neutral and ionic species points to their potential application as proton conductors. The analysis of the ab initio data highlights similarities as well as discrepancies from the rigid-ions force-field picture and suggests directions for the improvement of empirical models.

  14. Enhancement of encaged electron concentration by Sr(2+) doping and improvement of Gd(3+) emission through controlling encaged anions in conductive C12A7 phosphors.

    PubMed

    Zhang, Meng; Liu, Yuxue; Zhu, Hancheng; Yan, Duanting; Yang, Jian; Zhang, Xinyang; Liu, Chunguang; Xu, Changshan

    2016-07-28

    Conductive C12A7:0.1%Gd(3+),y%Sr(2+) powders with different Sr(2+) doping concentrations have been prepared in a H2 atmosphere by a solid state method in combination with subsequent UV-irradiation. The encaged electron concentration could be modulated through tuning Sr(2+) doping and its maximum value reaches 2.3 × 10(19) cm(-3). This is attributed to the competition between enhanced uptake and the release of the encaged anions during their formation and diffusion processes and the suppression of encaged electrons generation due to the increased encaged OH(-) anions and the decreased encaged O(2-) anions. Although there exists encaged electrons and different encaged anions (O(2-), H(-) and OH(-)) in C12A7 conductive powders prepared through the hydrogen route, a dominant local environment around Gd(3+) could be observed using electron spin resonance (ESR) detection. It can be ascribed to the stronger coupling of the encaged OH(-) to the framework of C12A7 than those of the encaged electrons, O(2-) and H(-) anions. In addition, emission of Gd(3+) ions is enhanced under UV or low voltage electron beam excitation and a new local environment around Gd(3+) ions appears through the thermal annealing in air because of the decrease of the encaged OH(-) anions and the increase of the encaged O(2-) anions. Our results suggested that Sr(2+) doping in combination with thermal annealing in air is an effective strategy for increasing the conductive performance and enhancing the emission of rare earth ions doped into C12A7 conductive phosphors for low-voltage field emission displays (FEDs).

  15. Interaction of bovine serum albumin with N-acyl amino acid based anionic surfactants: Effect of head-group hydrophobicity.

    PubMed

    Ghosh, Subhajit; Dey, Joykrishna

    2015-11-15

    The function of a protein depends upon its structure and surfactant molecules are known to alter protein structure. For this reason protein-surfactant interaction is important in biological, pharmaceutical, and cosmetic industries. In the present work, interactions of a series of anionic surfactants having the same hydrocarbon chain length, but different amino acid head group, such as l-alanine, l-valine, l-leucine, and l-phenylalanine with the transport protein, bovine serum albumin (BSA), were studied at low surfactant concentrations using fluorescence and circular dichroism (CD) spectroscopy, and isothermal titration calorimetry (ITC). The results of fluorescence measurements suggest that the surfactant molecules bind simultaneously to the drug binding site I and II of the protein subdomain IIA and IIIA, respectively. The fluorescence as well as CD spectra suggest that the conformation of BSA goes to a more structured state upon surfactant binding at low concentrations. The binding constants of the surfactants were determined by the use of fluorescence as well as ITC measurements and were compared with that of the corresponding glycine-derived surfactant. The binding constant values clearly indicate a significant head-group effect on the BSA-surfactant interaction and the interaction is mainly hydrophobic in nature. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Three-Stream, Bicarbonate-Based Hemodialysis Solution Delivery System Revisited: With an Emphasis on Some Aspects of Acid-Base Principles.

    PubMed

    Lew, Susie Q; Kohn, Orly F; Cheng, Yuk-Lun; Kjellstrand, Carl M; Ing, Todd S

    2017-06-01

    Hemodialysis patients can acquire buffer base (i.e., bicarbonate and buffer base equivalents of certain organic anions) from the acid and base concentrates of a three-stream, dual-concentrate, bicarbonate-based, dialysis solution delivery machine. The differences between dialysis fluid concentrate systems containing acetic acid versus sodium diacetate in the amount of potential buffering power were reviewed. Any organic anion such as acetate, citrate, or lactate (unless when combined with hydrogen) delivered to the body has the potential of being converted to bicarbonate. The prescribing physician aware of the role that organic anions in the concentrates can play in providing buffering power to the final dialysis fluid, will have a better knowledge of the amount of bicarbonate and bicarbonate precursors delivered to the patient. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  17. Hyaluronic acid concentration in liver diseases.

    PubMed

    Gudowska, Monika; Gruszewska, Ewa; Panasiuk, Anatol; Cylwik, Bogdan; Flisiak, Robert; Świderska, Magdalena; Szmitkowski, Maciej; Chrostek, Lech

    2016-11-01

    The aim of this study was to evaluate the effect of liver diseases of different etiologies and clinical severity of liver cirrhosis on the serum level of hyaluronic acid. The results were compared with noninvasive markers of liver fibrosis: APRI, GAPRI, HAPRI, FIB-4 and Forn's index. Serum samples were obtained from 20 healthy volunteers and patients suffering from alcoholic cirrhosis (AC)-57 patients, non-alcoholic cirrhosis (NAC)-30 and toxic hepatitis (HT)-22. Cirrhotic patients were classified according to Child-Pugh score. Hyaluronic acid concentration was measured by the immunochemical method. Non-patented indicators were calculated using special formulas. The mean serum hyaluronic acid concentration was significantly higher in AC, NAC and HT group in comparison with the control group. There were significant differences in the serum hyaluronic acid levels between liver diseases, and in AC they were significantly higher than those in NAC and HT group. The serum hyaluronic acid level differs significantly due to the severity of cirrhosis and was the highest in Child-Pugh class C. The sensitivity, specificity, accuracy, positive and negative predictive values and the area under the ROC curve for hyaluronic acid and all non-patented algorithms were high and similar to each other. We conclude that the concentration of hyaluronic acid changes in liver diseases and is affected by the severity of liver cirrhosis. Serum hyaluronic acid should be considered as a good marker for noninvasive diagnosis of liver damage, but the combination of markers is more useful.

  18. Electronic structures and spectra of two antioxidants: uric acid and ascorbic acid

    NASA Astrophysics Data System (ADS)

    Shukla, M. K.; Mishra, P. C.

    1996-04-01

    Electronic absorption and fluorescence spectra of aqueous solutions of two well known antioxidants, uric acid and ascorbic acid (vitamin C), have been studied at different pH. The observed spectra have been interpreted in terms of neutral and anionic forms of the molecules with the help of molecular orbital calculations. The N 3 site of uric acid has been shown to be the most acidic. Fluorescence of uric acid seems to originate from an anion of the molecule in a wide pH range. Around pH 3, both the neutral and anionic forms of ascorbic acid appear to be present in aqueous solutions. In aqueous media, ascorbic acid appears to get converted easily to its dehydro form and this conversion does not seem to be reversible. An anion of dehydroascorbic acid seems to be formed on heating dehydroascorbic acid in aqueous solutions.

  19. Discovery and Validation of Pyridoxic Acid and Homovanillic Acid as Novel Endogenous Plasma Biomarkers of Organic Anion Transporter (OAT) 1 and OAT3 in Cynomolgus Monkeys.

    PubMed

    Shen, Hong; Nelson, David M; Oliveira, Regina V; Zhang, Yueping; Mcnaney, Colleen A; Gu, Xiaomei; Chen, Weiqi; Su, Ching; Reily, Michael D; Shipkova, Petia A; Gan, Jinping; Lai, Yurong; Marathe, Punit; Humphreys, W Griffith

    2018-02-01

    Perturbation of organic anion transporter (OAT) 1- and OAT3-mediated transport can alter the exposure, efficacy, and safety of drugs. Although there have been reports of the endogenous biomarkers for OAT1/3, none of these have all of the characteristics required for a clinical useful biomarker. Cynomolgus monkeys were treated with intravenous probenecid (PROB) at a dose of 40 mg/kg in this study. As expected, PROB increased the area under the plasma concentration-time curve (AUC) of coadministered furosemide, a known substrate of OAT1 and OAT3, by 4.1-fold, consistent with the values reported in humans (3.1- to 3.7-fold). Of the 233 plasma metabolites analyzed using a liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based metabolomics method, 29 metabolites, including pyridoxic acid (PDA) and homovanillic acid (HVA), were significantly increased after either 1 or 3 hours in plasma from the monkeys pretreated with PROB compared with the treated animals. The plasma of animals was then subjected to targeted LC-MS/MS analysis, which confirmed that the PDA and HVA AUCs increased by approximately 2- to 3-fold by PROB pretreatments. PROB also increased the plasma concentrations of hexadecanedioic acid (HDA) and tetradecanedioic acid (TDA), although the increases were not statistically significant. Moreover, transporter profiling assessed using stable cell lines constitutively expressing transporters demonstrated that PDA and HVA are substrates for human OAT1, OAT3, OAT2 (HVA), and OAT4 (PDA), but not OCT2, MATE1, MATE2K, OATP1B1, OATP1B3, and sodium taurocholate cotransporting polypeptide. Collectively, these findings suggest that PDA and HVA might serve as blood-based endogenous probes of cynomolgus monkey OAT1 and OAT3, and investigation of PDA and HVA as circulating endogenous biomarkers of human OAT1 and OAT3 function is warranted. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

  20. Profound metabolic acidosis from pyroglutamic acidemia: an underappreciated cause of high anion gap metabolic acidosis.

    PubMed

    Green, Thomas J; Bijlsma, Jan Jaap; Sweet, David D

    2010-09-01

    The workup of the emergency patient with a raised anion gap metabolic acidosis includes assessment of the components of “MUDPILES” (methanol; uremia; diabetic ketoacidosis; paraldehyde; isoniazid, iron or inborn errors of metabolism; lactic acid; ethylene glycol; salicylates). This approach is usually sufficient for the majority of cases in the emergency department; however, there are many other etiologies not addressed in this mnemonic. Organic acids including 5-oxoproline (pyroglutamic acid) are rare but important causes of anion gap metabolic acidosis. We present the case of a patient with profound metabolic acidosis with raised anion gap, due to pyroglutamic acid in the setting of malnutrition and chronic ingestion of acetaminophen.

  1. Anion channels in the sea urchin sperm plasma membrane.

    PubMed

    Morales, E; de la Torre, L; Moy, G W; Vacquier, V D; Darszon, A

    1993-10-01

    Ionic fluxes in sea urchin sperm plasma membrane regulate cell motility and the acrosome reaction (AR). Although cationic channels mediate some of the ionic movements, little is known about anion channels in these cells. The fusion of sperm plasma membranes into lipid bilayers allowed identification of a 150 pS anion channel. This anion channel was enriched from detergent-solubilized sperm plasma membranes using a wheat germ agglutinin Sepharose column. Vesicles formed from this preparation were fused into black lipid membranes (BLM), yielding single channel anion-selective activity with the properties of those found in the sperm membranes. The following anion selectivity sequence was found: NO3- > CNS- > Br- > Cl-. This anion channel has a high open probability at the holding potentials tested, it is partially blocked by 4,4'-diisothiocyano-2,2'-stilbendisulfonic acid (DIDS), and it often displays substates. The sperm AR was also inhibited by DIDS.

  2. Simultaneous separation of inorganic anions and metal-citrate complexes on a zwitterionic stationary phase with on-column complexation.

    PubMed

    Nesterenko, Ekaterina P; Nesterenko, Pavel N; Paull, Brett

    2008-12-05

    The retention and separation selectivity of inorganic anions and on-column derivatised negatively charged citrate or oxalate metal complexes on reversed-phase stationary phases dynamically coated with N-(dodecyl-N,N-dimethylammonio)undecanoate (DDMAU) has been investigated. The retention mechanism for the metal-citrate complexes was predominantly anion exchange, although the amphoteric/zwitterionic nature of the stationary phase coating undoubtedly also contributed to the unusual separation selectivity shown. A mixture of 10 inorganic anions and metal cations was achieved using a 20 cm monolithic DDMAU modified column and a 1 mM citrate eluent, pH 4.0, flow rate equal to 0.8 mL/min. Selectivity was found to be strongly pH dependent, allowing additional scope for manipulation of solute retention, and thus application to complex samples. This is illustrated with the analysis of an acidic mine drainage sample with a range of inorganic anions and transition metal cations, varying significantly in their concentrations levels.

  3. Transepithelial transport of PEGylated anionic poly(amidoamine) dendrimers: implications for oral drug delivery.

    PubMed

    Sweet, Deborah M; Kolhatkar, Rohit B; Ray, Abhijit; Swaan, Peter; Ghandehari, Hamidreza

    2009-08-19

    The purpose of this work was to assess the impact of PEGylation on transepithelial transport of anionic poly(amidoamine) dendrimers. Cytotoxicity, uptake and transport across Caco-2 cells of PEGylated G3.5 and G4.5 PAMAM dendrimers were studied. Methoxy polyethylene glycol (750 Da) was conjugated to carboxylic acid-terminated PAMAM dendrimers at feed ratios of 1, 2 and 4 PEG per dendrimer. Compared to the control, PEGylation of anionic dendrimers did not significantly alter cytotoxicity up to a concentration of 0.1 mM. PEGylation of G3.5 dendrimers significantly decreased cellular uptake and transepithelial transport while PEGylation of G4.5 dendrimers led to a significant increase in uptake, but also a significant decrease in transport. Dendrimer PEGylation reduced the opening of tight junctions as evidenced by confocal microscopy techniques. Modulation of the tight junctional complex correlated well with changes in PEGylated dendrimer transport and suggests that anionic dendrimers are transported primarily through the paracellular route. PEGylated dendrimers show promise in oral delivery applications where increased functionality for drug conjugation and release is desired.

  4. Transepithelial Transport of PEGylated Anionic Poly(amidoamine) Dendrimers: Implications for Oral Drug Delivery

    PubMed Central

    Sweet, Deborah M.; Kolhatkar, Rohit B.; Ray, Abhijit; Swaan, Peter; Ghandehari, Hamidreza

    2009-01-01

    The purpose of this work was to assess the impact of PEGylation on transepithelial transport of anionic poly(amidoamine) dendrimers. Cytotoxicity, uptake and transport across Caco-2 cells of PEGylated G3.5 and G4.5 PAMAM dendrimers were studied. Methoxy polyethylene glycol (750 Da) was conjugated to carboxylic acid-terminated PAMAM dendrimers at feed ratios of 1, 2 and 4 PEG per dendrimer. Compared to the control, PEGylation of anionic dendrimers did not significantly alter cytotoxicity up to a concentration of 0.1 mM. PEGylation of G3.5 dendrimers significantly decreased cellular uptake and transepithelial transport while PEGylation of G4.5 dendrimers led to a significant increase in uptake, but also a significant decrease in transport. Dendrimer PEGylation reduced the opening of tight junctions as evidenced by confocal microscopy techniques. Modulation of the tight junctional complex correlated well with changes in PEGylated dendrimer transport and suggests that anionic dendrimers are transported primarily through the paracellular route. PEGylated dendrimers show promise in oral delivery applications where increased functionality for drug conjugation and release is desired. PMID:19393702

  5. Impact of Glycolate Anion on Aqueous Corrosion in DWPF and Downstream Facilities

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

    Mickalonis, J.

    Glycolic acid is being evaluated as an alternate reductant in the preparation of high level waste for the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). During processing, the glycolic acid may not be completely consumed with small quantities of the glycolate anion being carried forward to other high level waste (HLW) facilities. The SRS liquid waste contractor requested an assessment of the impact of the glycolate anion on the corrosion of the materials of construction (MoC) throughout the waste processing system since this impact had not been previously evaluated. A literature review revealed that corrosion datamore » were not available for the MoCs in glycolic-bearing solutions applicable to SRS systems. Data on the material compatibility with only glycolic acid or its derivative products were identified; however, data were limited for solutions containing glycolic acid or the glycolate anion. For the proprietary coating systems applied to the DWPF concrete, glycolic acid was deemed compatible since the coatings were resistant to more aggressive chemistries than glycolic acid. Additionally, similar coating resins showed acceptable resistance to glycolic acid.« less

  6. Impact of Glycolate Anion on Aqueous Corrosion in DWPF and Downstream Facilities

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

    Mickalonis, J.

    Glycolic acid is being evaluated as an alternate reductant in the preparation of high level waste for the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). During processing, the glycolic acid may not be completely consumed with small quantities of the glycolate anion being carried forward to other high level waste (HLW) facilities. The SRS liquid waste contractor requested an assessment of the impact of the glycolate anion on the corrosion of the materials of construction (MoC) throughout the waste processing system since this impact had not been previously evaluated. A literature review revealed that corrosion datamore » were not available for the MoCs in glycolic-bearing solutions applicable to SRS systems. Data on the material compatibility with only glycolic acid or its derivative products were identified; however, data were limited for solutions containing glycolic acid or the glycolate anion. For the proprietary coating systems applied to the DWPF concrete, glycolic acid was deemed compatible since the coatings were resistant to more aggressive chemistries than glycolic acid. Additionally similar coating resins showed acceptable resistance to glycolic acid.« less

  7. Evaluation of an anion exchange resin-based method for concentration of F-RNA coliphages (enteric virus indicators) from water samples.

    PubMed

    Pérez-Méndez, A; Chandler, J C; Bisha, B; Goodridge, L D

    2014-08-01

    Enteric viral contaminants in water represent a public health concern, thus methods for detecting these viruses or their indicator microorganisms are needed. Because enteric viruses and their viral indicators are often found at low concentrations in water, their detection requires upfront concentration methods. In this study, a strong basic anion exchange resin was evaluated as an adsorbent material for the concentration of F-RNA coliphages (MS2, Qβ, GA, and HB-P22). These coliphages are recognized as enteric virus surrogates and fecal indicator organisms. Following adsorption of the coliphages from 50ml water samples, direct RNA isolation and real time RT-PCR detection were performed. In water samples containing 10(5)pfu/ml of the F-RNA coliphages, the anion exchange resin (IRA-900) adsorbed over 96.7% of the coliphages present, improving real time RT-PCR detection by 5-7 cycles compared to direct testing. F-RNA coliphage RNA recovery using the integrated method ranged from 12.6% to 77.1%. Resin-based concentration of samples with low levels of the F-RNA coliphages allowed for 10(0)pfu/ml (MS2 and Qβ) and 10(-1)pfu/ml (GA and HB-P22) to be detected. The resin-based method offers considerable advantages in cost, speed, simplicity and field adaptability. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Ca(2+)-activated anion channels and membrane depolarizations induced by blue light and cold in Arabidopsis seedlings

    NASA Technical Reports Server (NTRS)

    Lewis, B. D.; Karlin-Neumann, G.; Davis, R. W.; Spalding, E. P.; Evans, M. L. (Principal Investigator)

    1997-01-01

    The activation of an anion channel in the plasma membrane of Arabidopsis thaliana hypocotyls by blue light (BL) is believed to be a signal-transducing event leading to growth inhibition. Here we report that the open probability of this particular anion channel depends on cytoplasmic Ca2+ ([Ca2+]cyt) within the concentration range of 1 to 10 microM, raising the possibility that BL activates the anion channel by increasing [Ca2+]cyt. Arabidopsis seedlings cytoplasmically expressing aequorin were generated to test this possibility. Aequorin luminescence did not increase during or after BL, providing evidence that Ca2+ does not play a second-messenger role in the activation of anion channels. However, cold shock simultaneously triggered a large increase in [Ca2+]cyt and a 110-mV transient depolarization of the plasma membrane. A blocker of the anion channel, 5-nitro-2-(3-phenylpropylamino)-benzoic acid, blocked 61% of the cold-induced depolarization without affecting the increase in [Ca2+]cyt. These data led us to propose that cold shock opens Ca2+ channels at the plasma membrane, allowing an inward, depolarizing Ca2+ current. The resulting large increase in [Ca2+]cyt activates the anion channel, which further depolarizes the membrane. Although an increase in [Ca2+]cyt may activate anion channels in response to cold, it appears that BL does so via a Ca(2+)-independent pathway.

  9. Manipulating the dietary cation-anion difference via drenching to early-lactation dairy cows grazing pasture.

    PubMed

    Roche, J R; Petch, S; Kay, J K

    2005-01-01

    Diets offered to grazing dairy cows can vary considerably in their dietary cation-anion difference (DCAD) and are often well in excess of what has been considered optimal. The effects of a range of DCAD on the health and production of pasture-based dairy cows in early lactation was examined in a randomized block design. Four groups of 8 cows were offered a generous allowance of pasture (45 +/- 6 kg/d of dry matter (DM) per cow) for 35 d and achieved mean pasture intakes of approximately 17 kg/d of DM per cow. Cows were drenched twice daily with varying combinations of mineral compounds to alter the DCAD. Dietary cation-anion difference ranged from +23 to +88 mEq/100 g of DM. A linear increase in blood pH and HCO(3)(-) concentration and blood base excess, and a curvilinear increase in the pH of urine with increasing DCAD indicated a nonrespiratory effect of DCAD on metabolic acid-base balance. Plasma concentrations of Mg, K, and Cl declined as DCAD increased, whereas Na concentration increased. Urinary excretion of Ca decreased linearly as DCAD increased, although the data suggest that the decline may be curvilinear. These results in conjunction with the increased concentrations of ionized Ca suggest that intestinal absorption of Ca or bone resorption, or both, increased as DCAD declined. Dry matter intake, as measured using indigestible markers, was not significantly affected by DCAD. However, the linear increase in the yield of linolenic acid, vaccenic acid, and cis-9, trans-11 conjugated linoleic acid in milk, as DCAD increased is consistent with a positive effect of DCAD on DM intake. Increasing DCAD did not significantly affect milk yield or milk protein, but the concentration and yield of milk fat linearly increased with increasing DCAD. The increased milk fat yield was predominantly a result of increased de novo synthesis in the mammary epithelial cells, although an increase in the yield of preformed fatty acids also occurred. Milk production results suggest

  10. Anion complexation and the Hofmeister effect.

    PubMed

    Carnegie, Ryan S; Gibb, Corinne L D; Gibb, Bruce C

    2014-10-20

    The (1)H NMR spectroscopic analysis of the binding of the ClO4(-) anion to the hydrophobic, concave binding site of a deep-cavity cavitand is presented. The strength of association between the host and the ClO4(-) anion is controlled by both the nature and concentration of co-salts in a manner that follows the Hofmeister series. A model that partitions this trend into the competitive binding of the co-salt anion to the hydrophobic pocket of the host and counterion binding to its external carboxylate groups successfully accounts for the observed changes in ClO4(-) affinity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Boric acid and boronic acids inhibition of pigeonpea urease.

    PubMed

    Reddy, K Ravi Charan; Kayastha, Arvind M

    2006-08-01

    Urease from the seeds of pigeonpea was competitively inhibited by boric acid, butylboronic acid, phenylboronic acid, and 4-bromophenylboronic acid; 4-bromophenylboronic acid being the strongest inhibitor, followed by boric acid > butylboronic acid > phenylboronic acid, respectively. Urease inhibition by boric acid is maximal at acidic pH (5.0) and minimal at alkaline pH (10.0), i.e., the trigonal planar B(OH)3 form is a more effective inhibitor than the tetrahedral B(OH)4 -anionic form. Similarly, the anionic form of phenylboronic acid was least inhibiting in nature.

  12. [Water-soluble anions of atmosphere on Tianwan nuclear power station].

    PubMed

    Zhao, Heng-Qiang; He, Ying; Zheng, Xiao-Ling; Chen, Fa-Rong; Pang, Shi-Ping; Wang, Cai-Xia; Wang, Xiao-Ru

    2010-11-01

    Three major water-soluble anions (Cl-, SO4(2-) and NO3-) in the atmosphere of the Tianwan nuclear power station in Lianyungang were determined by ion chromatography from June 2005 to May 2006. The results showed that the annual average concentration of Cl-, SO4(2-) and NO3- in the atmosphere of Tianwan nuclear power station was (33.12 +/- 53.63) microg x m(-3), (53.34 +/- 30.34) microg x m(-3) and (8.34 +/- 4.47) microg x m(-3), respectively. The concentrations of the three water-soluble anions showed evident trend of seasonal variation. The concentrations of Cl-, SO4(2-) reached the highest level in summer and the lowest level in winter, while the concentration of NO3- in autumn and winter was higher than those in summer and spring. Meteorological parameters such as wind direction, wind speed, temperature and relative humidity were studied and showed definite influence to the anions concentration of the atmosphere. This is the first simultaneous monitoring of corrosive anions in the atmosphere of Chinese coastal nuclear power plant, and it will provide basis for the prevention of marine atmospheric corrosion, which will ensure the safely operating of our nuclear power industry.

  13. Preparation of pH-sensitive anionic liposomes designed for drug delivery system (DDS) application.

    PubMed

    Aoki, Asami; Akaboshi, Hikaru; Ogura, Taku; Aikawa, Tatsuo; Kondo, Takeshi; Tobori, Norio; Yuasa, Makoto

    2015-01-01

    We prepared pH-sensitive anionic liposomes composed solely of anionic bilayer membrane components that were designed to promote efficient release of entrapped agents in response to acidic pH. The pH-sensitive anionic liposomes showed high dispersion stability at neutral pH, but the fluidity of the bilayer membrane was enhanced in an acidic environment. These liposomes were rather simple and were composed of dimyristoylphosphatidylcholine (DMPC), an anionic bilayer membrane component, and polyoxyethylene sorbitan monostearate (Tween 80). In particular, the present pH-sensitive anionic liposomes showed higher temporal stability than those of conventional DMPC/DPPC liposomes. We found that pHsensitive properties strongly depended on the molecular structure, pKa value, and amount of an incorporated anionic bilayer membrane component, such as sodium oleate (SO), dimyristoylphosphatidylserine (DMPS), or sodium β-sitosterol sulfate (SS). These results provide an opportunity to manipulate liposomal stability in a pH-dependent manner, which could lead to the formulation of a high performance drug delivery system (DDS).

  14. Seasonal evolution of anionic, cationic and non-ionic surfactant concentrations in coastal aerosols from Askö, Sweden

    NASA Astrophysics Data System (ADS)

    Gérard, Violaine; Nozière, Barbara; Baduel, Christine

    2015-04-01

    Surfactants present in atmospheric aerosols are expected to enhance the activation into cloud droplets by acting on one of the two key parameters of the Köhler equation: the surface tension, σ. But because the magnitude of this effect and its regional and temporal variability are still highly uncertain [1,2], various approaches have been developed to evidence it directly in the atmosphere. This work presents the analysis of surfactants present in PM2.5 aerosol fractions collected at the coastal site of Askö, Sweden (58° 49.5' N, 17° 39' E) from July to October 2010. The total surfactant fraction was extracted from the samples using an improved double extraction technique. Surface tension measurements performed with the pendant drop technique [3] indicated the presence of very strong surfactants (σ ~ 30 - 35 mN/m) in these aerosols. In addition, these extractions were combined with colorimetric methods to determine the anionic, cationic and non-ionic surfactant concentrations [4,5], and provided for the first time interference-free surfactant concentrations in atmospheric aerosols. At this site, the total surfactant concentration in the PM2.5 samples varied between 7 to 150 mM and was dominated by anionic and non-ionic ones. The absolute surface tension curves obtained for total surfactant fraction displayed Critical Micelle Concentrations (CMC) in the range 50 - 400 uM, strongly suggesting a biological origin for the surfactants. The seasonal evolution of these concentrations and their relationships with environmental or meteorological parameters at the site will be discussed. [1] Ekström, S., Nozière, B. et al., Biogeosciences, 2010, 7, 387 [2] Baduel, C., Nozière, B., Jaffrezo, J.-L., Atmos. Environ., 2012, 47, 413 [3] Nozière, B., Baduel, C., Jaffrezo, J.-L., Nat. Commun., 2014, 5, 1 [4] Latif, M. T.; Brimblecombe, P. Environ. Sci. Technol., 2004, 38, 6501 [5] Pacheco e Silva et al., Method to measure surfactant in fluid, 2013, US 2013/0337568 A1

  15. Sulfhydryl modification of V449C in the glutamate transporter EAAT1 abolishes substrate transport but not the substrate-gated anion conductance

    PubMed Central

    Seal, Rebecca P.; Shigeri, Yasushi; Eliasof, Scott; Leighton, Barbara H.; Amara, Susan G.

    2001-01-01

    Excitatory amino acid transporters (EAATs) buffer and remove synaptically released l-glutamate and maintain its concentrations below neurotoxic levels. EAATs also mediate a thermodynamically uncoupled substrate-gated anion conductance that may modulate cell excitability. Here, we demonstrate that modification of a cysteine substituted within a C-terminal domain of EAAT1 abolishes transport in both the forward and reverse directions without affecting activation of the anion conductance. EC50s for l-glutamate and sodium are significantly lower after modification, consistent with kinetic models of the transport cycle that link anion channel gating to an early step in substrate translocation. Also, decreasing the pH from 7.5 to 6.5 decreases the EC50 for l-glutamate to activate the anion conductance, without affecting the EC50 for the entire transport cycle. These findings demonstrate for the first time a structural separation of transport and the uncoupled anion flux. Moreover, they shed light on some controversial aspects of the EAAT transport cycle, including the kinetics of proton binding and anion conductance activation. PMID:11752470

  16. Association between Serum Unmetabolized Folic Acid Concentrations and Folic Acid from Fortified Foods.

    PubMed

    Palchetti, Cecília Zanin; Paniz, Clóvis; de Carli, Eduardo; Marchioni, Dirce M; Colli, Célia; Steluti, Josiane; Pfeiffer, Christine M; Fazili, Zia; Guerra-Shinohara, Elvira Maria

    2017-01-01

    To investigate the association between serum unmetabolized folic acid (UMFA) concentrations and folic acid from fortified foods and nutrients known as dietary methyl-group donors (folate, methionine, choline, betaine and vitamins B2, B6 and B12) in participants exposed to mandatory fortification of wheat and maize flours with folic acid. Cross-sectional study carried out with 144 healthy Brazilian participants, both sexes, supplement nonusers. Serum folate, UMFA, vitamin B12 and total plasma homocysteine (tHcy) were biochemically measured. Dietary intake was assessed by 2 non-consecutive 24-hour dietary recalls (24-HRs) and deattenuated energy-adjusted nutrient data were used for statistical analysis. Ninety eight (68.1%) participants were women. Median (interquartile range) age was 35.5 (28.0-52.0) years. Elevated serum folate concentrations (>45 nmol/L) were found in 17 (11.8%), while folate deficiency (<7 nmol/L) in 10 (6.9%) participants. No one had vitamin B12 deficiency (<148 pmol/L). An elevated serum UMFA concentration was defined as > 1 nmol/L (90th percentile). UMFA concentrations were positively correlated with folic acid intake and negatively correlated to choline, methionine and vitamin B6 intakes. Participants in the lowest quartile of UMFA concentrations had lower dietary intake of total folate (DFEs) and folic acid, and higher dietary intake of methionine, choline and vitamin B6 than participants in the highest quartile of UMFA. Folic acid intake (OR [95% CI] = 1.02 [1.01-1.04)] and being a male (OR [95% CI] = 0.40 [0.19-0.87) were associated with increased and reduced odds for UMFA concentrations > 0.55 nmol/L (median values), respectively. UMFA concentrations were directly influenced by folic acid intake from fortified foods in a healthy convenience sample of adult Brazilians exposed to mandatory flour fortification with folic acid.

  17. High Concentrations of Tranexamic Acid Inhibit Ionotropic Glutamate Receptors.

    PubMed

    Lecker, Irene; Wang, Dian-Shi; Kaneshwaran, Kirusanthy; Mazer, C David; Orser, Beverley A

    2017-07-01

    The antifibrinolytic drug tranexamic acid is structurally similar to the amino acid glycine and may cause seizures and myoclonus by acting as a competitive antagonist of glycine receptors. Glycine is an obligatory co-agonist of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors. Thus, it is plausible that tranexamic acid inhibits NMDA receptors by acting as a competitive antagonist at the glycine binding site. The aim of this study was to determine whether tranexamic acid inhibits NMDA receptors, as well as α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and kainate subtypes of ionotropic glutamate receptors. Tranexamic acid modulation of NMDA, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, and kainate receptors was studied using whole cell voltage-clamp recordings of current from cultured mouse hippocampal neurons. Tranexamic acid rapidly and reversibly inhibited NMDA receptors (half maximal inhibitory concentration = 241 ± 45 mM, mean ± SD; 95% CI, 200 to 281; n = 5) and shifted the glycine concentration-response curve for NMDA-evoked current to the right. Tranexamic acid also inhibited α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (half maximal inhibitory concentration = 231 ± 91 mM; 95% CI, 148 to 314; n = 5 to 6) and kainate receptors (half maximal inhibitory concentration = 90 ± 24 mM; 95% CI, 68 to 112; n = 5). Tranexamic acid inhibits NMDA receptors likely by reducing the binding of the co-agonist glycine and also inhibits α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and kainate receptors. Receptor blockade occurs at high millimolar concentrations of tranexamic acid, similar to the concentrations that occur after topical application to peripheral tissues. Glutamate receptors in tissues including bone, heart, and nerves play various physiologic roles, and tranexamic acid inhibition of these receptors may contribute to adverse drug effects.

  18. A New Approach to Non-Coordinating Anions: Lewis Acid Enhancement of Porphyrin Metal Centers in a Zwitterionic Metal$-$Organic Framework

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

    Johnson, Jacob A.; Petersen, Brenna M.; Kormos, Attila

    Here, we describe a new strategy to generate non-coordinating anions using zwitterionic metal–organic frameworks (MOFs). By assembly of anionic inorganic secondary building blocks (SBUs) ([In(CO 2) 4] $-$) with cationic metalloporphyrin-based organic linkers, we prepared zwitterionic MOFs in which the complete internal charge separation effectively prevents the potential binding of the counteranion to the cationic metal center. We demonstrate the enhanced Lewis acidity of Mn III- and Fe III-porphyrins in the zwitterionic MOFs in three representative electrocyclization reactions: [2 + 1] cycloisomerization of enynes, [3 + 2] cycloaddition of aziridines and alkenes, and [4 + 2] hetero-Diels–Alder cycloaddition of aldehydesmore » with dienes. Lastly, this work paves a new way to design functional MOFs for tunable chemical catalysis.« less

  19. Inhibition of nuclear waste solutions containing multiple aggressive anions

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

    Congdon, J.W.

    1988-01-01

    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.

  20. Inhibition of nuclear waste solutions containing multiple aggressive anions

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

    Congdon, J.W.

    1988-05-01

    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.

  1. Determination of glycerophosphate and other anions in dentifrices by ion chromatography.

    PubMed

    Chen, Yongxin; Ye, Mingli; Cui, Hairong; Wu, Feiyan; Zhu, Yan; Fritz, James S

    2006-06-16

    Simple, reliable and sensitive analytical methods to determine the anions, such as fluoride, monofluorophaosphate, glycerophosphate related to anticaries are necessary for basic investigations of anticaries and quality control of dentifrices. A method for the simultaneous determination of organic acids, organic anions and inorganic anions in the sample of commercial toothpaste is proposed. Nine anions (fluoride, chloride, nitrite, nitrate, sulfate, phosphate, monofluorophaosphate, glycerophosphate and oxalic acid) were analyzed by means of ion chromatography using a gradient elution with KOH as mobile phase, IonPac AS18 as the separation column and suppressed conductivity detection. Optimized analytical conditions were further validated in terms of accuracy, precision and total uncertainty and the results showed the reliability of the IC method. The relative standard deviations (RSD) of the retention time and peak area of all species were less than 0.170 and 1.800%, respectively. The correlation coefficients for target analytes ranged from 0.9985 to 0.9996. The detection limit (signal to noise ratio of 3:1) of this method was at low ppb level (<15 ppb). The spiked recoveries for the anions were 96-103%. The method was applied to toothpaste without interferences.

  2. Purification of organic acids by chromatography with strong anionic resins: Investigation of uptake mechanisms.

    PubMed

    Lemaire, Julien; Blanc, Claire-Line; Lutin, Florence; Théoleyre, Marc-André; Stambouli, Moncef; Pareau, Dominique

    2016-08-05

    Bio-based organic acids are promising renewable carbon sources for the chemical industry. However energy-consuming purification processes are used, like distillation or crystallization, to reach high purities required in some applications. That is why preparative chromatography was studied as an alternative separation technique. In a previous work dealing with the purification of lactic, succinic and citric acids, the Langmuir model was insufficient to explain the elution profiles obtained with a strong anionic resin. Consequently the Langmuir model was coupled with a usual ion-exchange model to take into account the retention of their conjugate bases (<2%), which are commonly neglected at low pH (<1.5). Elution simulations with both uptake mechanisms fitted very well with experimental pulse tests. Only two parameters were optimized (equilibrium constant of acid uptake and ion-exchange selectivity coefficient of conjugate base) and their value were coherent with experimental and resin suppliers' data. These results confirmed that the singular tailing and apparent delay observed with succinic and citric acids can be explained by the high affinity of succinate and citrate for resin cationic sites. The model was implemented in a preparative chromatography simulation program in order to optimize operating parameters of our pilot-scale ISMB unit (Improved Simulated Moving Bed). The comparison with experimental ISMB profiles was conclusive. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Anionic poly(amino acid)s dissolve F-actin and DNA bundles, enhance DNase activity, and reduce the viscosity of cystic fibrosis sputum.

    PubMed

    Tang, Jay X; Wen, Qi; Bennett, Andrew; Kim, Brian; Sheils, Catherine A; Bucki, Robert; Janmey, Paul A

    2005-10-01

    Bundles of F-actin and DNA present in the sputum of cystic fibrosis (CF) patients but absent from normal airway fluid contribute to the altered viscoelastic properties of sputum that inhibit clearance of infected airway fluid and exacerbate the pathology of CF. Previous strategies to remove these filamentous aggregates have focused on DNase to enzymatically depolymerize DNA to constituent monomers and gelsolin to sever F-actin to small fragments. The high densities of negative surface charge on DNA and F-actin suggest that the bundles of these filaments, which alone exhibit a strong electrostatic repulsion, may be stabilized by multivalent cations such as histones, antimicrobial peptides, and other positively charged molecules prevalent in airway fluid. This study reports that bundles of DNA or F-actin formed after addition of histone H1 or lysozyme are efficiently dissolved by soluble multivalent anions such as polymeric aspartate or glutamate. Addition of poly-aspartate or poly-glutamate also disperses DNA and actin-containing bundles in CF sputum and lowers the elastic moduli of these samples to levels comparable to those obtained after treatment with DNase I or gelsolin. Addition of poly-aspartic acid also increased DNase activity when added to samples containing DNA bundles formed with histone H1. When added to CF sputum, poly-aspartic acid significantly reduced the growth of bacteria, suggesting activation of endogenous antibacterial factors. These findings suggest that soluble multivalent anions have potential alone or in combination with other mucolytic agents to selectively dissociate the large bundles of charged biopolymers that form in CF sputum.

  4. Evaluating of arsenic(V) removal from water by weak-base anion exchange adsorbents.

    PubMed

    Awual, M Rabiul; Hossain, M Amran; Shenashen, M A; Yaita, Tsuyoshi; Suzuki, Shinichi; Jyo, Akinori

    2013-01-01

    Arsenic contamination of groundwater has been called the largest mass poisoning calamity in human history and creates severe health problems. The effective adsorbents are imperative in response to the widespread removal of toxic arsenic exposure through drinking water. Evaluation of arsenic(V) removal from water by weak-base anion exchange adsorbents was studied in this paper, aiming at the determination of the effects of pH, competing anions, and feed flow rates to improvement on remediation. Two types of weak-base adsorbents were used to evaluate arsenic(V) removal efficiency both in batch and column approaches. Anion selectivity was determined by both adsorbents in batch method as equilibrium As(V) adsorption capacities. Column studies were performed in fixed-bed experiments using both adsorbent packed columns, and kinetic performance was dependent on the feed flow rate and competing anions. The weak-base adsorbents clarified that these are selective to arsenic(V) over competition of chloride, nitrate, and sulfate anions. The solution pH played an important role in arsenic(V) removal, and a higher pH can cause lower adsorption capacities. A low concentration level of arsenic(V) was also removed by these adsorbents even at a high flow rate of 250-350 h(-1). Adsorbed arsenic(V) was quantitatively eluted with 1 M HCl acid and regenerated into hydrochloride form simultaneously for the next adsorption operation after rinsing with water. The weak-base anion exchange adsorbents are to be an effective means to remove arsenic(V) from drinking water. The fast adsorption rate and the excellent adsorption capacity in the neutral pH range will render this removal technique attractive in practical use in chemical industry.

  5. Spectroscopic studies on the antioxidant activity of p-coumaric acid

    NASA Astrophysics Data System (ADS)

    Kiliç, Ismail; Yeşiloğlu, Yeşim

    2013-11-01

    p-coumaric acid (4-hydroxycinnamic acid), a phenolic acid, is a hydroxyl derivative of cinnamic acid. It decreases low density lipoprotein (LDL) peroxidation and reduces the risk of stomach cancer. In vitro radical scavenging and antioxidant capacity of p-coumaric acid were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2‧-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe2+) chelating activity and ferric ions (Fe3+) reducing ability. p-Coumaric acid inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45 μg/mL concentration. On the other hand, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and ascorbic acid displayed 66.8%, 69.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, p-coumaric acid had an effective DPPHrad scavenging, ABTSrad + scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe3+) reducing power and ferrous ions (Fe2+) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that p-coumaric acid can be used in the pharmacological and food industry because of these properties.

  6. Dibutyl Phosphoric Acid Solubility in High-Acid, Uranium-Bearing Solutions at SRS

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

    Pierce, R.A.

    1998-10-02

    The Savannah River Site has enriched uranium (EU) solution which has been stored for almost 10 years since being purified in the second uranium cycle of the H area solvent extraction process. The concentrations in solution are approximately 6 g/L U and about 0.1 M nitric acid. Residual tributylphosphate in the solutions has slowly hydrolyzed to form dibutyl phosphoric acid (HDBP) at concentrations averaging 50 mg/L. Uranium is known to form compounds with the dibutylphosphate ion (DBP) which have limited solubility. The potential to form uranium-DBP solids raises a nuclear criticality safety issue. Prior SRTC tests (WSRC-TR-98-00188) showed that U-DBPmore » solids precipitate at concentrations potentially attainable during the storage of enriched uranium solutions. Furthermore, evaporation of the existing EUS solution without additional acidification could result in the precipitation of U-DBP solids if the DBP concentration in the resulting solution exceeds 110 mg/L at ambient temperature. The same potential exists for evaporation of unwashed 1CU solutions. As a follow-up to the earlier studies, SRTC studied the solubility limits for solutions containing acid concentrations above 0.5M HNO3. The data obtained in these tests reveals a shift to higher levels of DBP solubility above 0.5M HNO3 for both 6 g/L and 12 g/L uranium solutions. Analysis of U-DBP solids from the tests identified a mixture of different molecular structures for the solids created. The analysis distinguished UO2(DBP)2 as the dominant compound present at low acid concentrations. As the acid concentration increases, the crystalline UO2(DBP)2 shows molecular substitutions and an increase in amorphous content. Further analysis by methods not available at SRS will be needed to better identify the specific compounds present. This data indicates that acidification prior to evaporation can be used to increase the margin of safety for the storage of the EUS solutions. Subsequent experimentation evaluated

  7. Serum bile acid concentrations in dairy cattle with hepatic lipidosis.

    PubMed

    Garry, F B; Fettman, M J; Curtis, C R; Smith, J A

    1994-01-01

    This study was designed to evaluate serum bile acid measurements as indicatory, of liver function and/or hepatic fat infiltration in dairy cattle. Serum bile acid concentrations were measured in healthy dairy cattle at different stages of lactation after fasting or feeding. Bile acid concentrations were compared with liver fat content and sulfobromophthalein (BSP) half-life (T 1/2). Serum bile acid concentrations were higher in cows in early lactation and with higher daily milk production. Compared with prefasting values, bile acid concentrations were decreased at 8, 14, and 24 hours of fasting. Blood samples from fed cows at 1- to 2-hour intervals had wide and inconsistent variations in bile acid concentration. Because serum bile acids correlated well with BSP T 1/2, it is suggested that both measurements evaluate a similar aspect of liver function. Neither bile acids nor BSP T 1/2 correlated with differences in liver fat content among cows. Because of large variability in serum bile acid concentrations in fed cows and the lack of correlation of measured values with liver fat content, bile acid determinations do not appear useful for showing changes in hepatic function in fed cows with subclinical hepatic lipidosis nor serve as a screening test for this condition.

  8. Molecular anions.

    PubMed

    Simons, Jack

    2008-07-24

    The experimental and theoretical study of molecular anions has undergone explosive growth over the past 40 years. Advances in techniques used to generate anions in appreciable numbers as well as new ion-storage, ion-optics, and laser spectroscopic tools have been key on the experimental front. Theoretical developments on the electronic structure and molecular dynamics fronts now allow one to achieve higher accuracy and to study electronically metastable states, thus bringing theory in close collaboration with experiment in this field. In this article, many of the experimental and theoretical challenges specific to studying molecular anions are discussed. Results from many research groups on several classes of molecular anions are overviewed, and both literature citations and active (in online html and pdf versions) links to numerous contributing scientists' Web sites are provided. Specific focus is made on the following families of anions: dipole-bound, zwitterion-bound, double-Rydberg, multiply charged, metastable, cluster-based, and biological anions. In discussing each kind of anion, emphasis is placed on the structural, energetic, spectroscopic, and chemical-reactivity characteristics that make these anions novel, interesting, and important.

  9. Optimization of SHINE Process: Design and Verification of Plant-Scale AG 1 Anion-Exchange Concentration Column and Titania Sorbent Pretreatment

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

    Stepinski, Dominique C.; Abdul, Momen; Youker, Amanda J.

    2016-06-01

    Argonne National Laboratory has developed a Mo-recovery and -purification system for the SHINE medical technologies process, which uses a uranyl sulfate solution for the accelerator-driven production of Mo-99. The objective of this effort is to reduce the processing time for the acidification of the Mo-99 product prior to loading onto a concentration column and concentration of the Mo-99 product solution. Two methods were investigated: (1) the replacement of the titania concentration column by an anion-exchange column to decrease processing time and increase the radioiodine-decontamination efficiency and (2) pretreatment of the titania sorbent to improve its effectiveness for the Mo-recovery andmore » -concentration columns. Promising results are reported for both methods.« less

  10. Myocardial concentrations of fatty acids in dogs with dilated cardiomyopathy.

    PubMed

    Smith, Caren E; Freeman, Lisa M; Meydani, Mohsen; Rush, John E

    2005-09-01

    To compare myocardial concentrations of fatty acids in dogs with dilated cardiomyopathy (DCM) with concentrations in control dogs. Myocardial tissues from 7 dogs with DCM and 16 control dogs. Myocardial tissues were homogenized, and total fatty acids were extracted and converted to methyl esters. Myocardial concentrations of fatty acids were analyzed by use of gas chromatography and reported as corrected percentages. The amount of docosatetraenoic acid (C22:4 n-6) was significantly higher in myocardial samples from dogs with DCM (range, 0.223% to 0.774%; median, 0.451%), compared with the amount in samples obtained from control dogs (range, 0.166% to 0.621%; median, 0.280%). There were no significant differences between DCM and control dogs for concentrations of any other myocardial fatty acids. Although concentrations of most myocardial fatty acids did not differ significantly between dogs with DCM and control dogs, the concentration of docosatetraenoic acid was significantly higher in dogs with DCM. Additional investigation in a larger population is warranted to determine whether this is a primary or secondary effect of the underlying disease and whether alterations in fatty acids may be a target for intervention in dogs with DCM.

  11. Oxygen anion (O- ) and hydroxide anion (HO- ) reactivity with a series of old and new refrigerants.

    PubMed

    Le Vot, Clotilde; Lemaire, Joël; Pernot, Pascal; Heninger, Michel; Mestdagh, Hélène; Louarn, Essyllt

    2018-04-01

    The reactivity of a series of commonly used halogenated compounds (trihalomethanes, chlorofluorocarbon, hydrochlorofluorocarbon, fluorocarbons, and hydrofluoroolefin) with hydroxide and oxygen anion is studied in a compact Fourier transform ion cyclotron resonance. O - is formed by dissociative electron attachment to N 2 O and HO - by a further ion-molecule reaction with ammonia. Kinetic experiments are performed by increasing duration of introduction of the studied molecule at a constant pressure. Hydroxide anion reactions mainly proceed by proton transfer for all the acidic compounds. However, nucleophilic substitution is observed for chlorinated and brominated compounds. For fluorinated compounds, a specific elimination of a neutral fluorinated alkene is observed in our results in parallel with the proton transfer reaction. Oxygen anion reacts rapidly and extensively with all compounds. Main reaction channels result from nucleophilic substitution, proton transfer, and formal H 2 + transfer. We highlight the importance of transfer processes (atom or ion) in the intermediate ion-neutral complex, explaining part of the observed reactivity and formed ions. In this paper, we present the first reactivity study of anions with HFO 1234yf. Finally, the potential of O - and HO - as chemical ionization reagents for trace analysis is discussed. Copyright © 2017 John Wiley & Sons, Ltd.

  12. Relationship of Cell Sap pH to Organic Acid Change During Ion Uptake 1

    PubMed Central

    Hiatt, A. J.

    1967-01-01

    Excised roots of barley (Hordeum vulgare, var. Campana) were incubated in KCl, K2SO4, CaCl2, and NaCl solutions at concentrations of 10−5 to 10−2 n. Changes in substrate solution pH, cell sap pH, and organic acid content of the roots were related to differences in cation and anion absorption. The pH of expressed sap of roots increased when cations were absorbed in excess of anions and decreased when anions were absorbed in excess of cations. The pH of the cell sap shifted in response to imbalances in cation and anion uptake in salt solutions as dilute as 10−5 n. Changes in cell sap pH were detectable within 15 minutes after the roots were placed in 10−3 n K2SO4. Organic acid changes in the roots were proportional to expressed sap pH changes induced by unbalanced ion uptake. Changes in organic acid content in response to differential cation and anion uptake appear to be associated with the low-salt component of ion uptake. PMID:16656506

  13. An anionic defensin from Plutella xylostella with potential activity against Bacillus thuringiensis.

    PubMed

    Xu, X-X; Zhang, Y-Q; Freed, S; Yu, J; Gao, Y-F; Wang, S; Ouyang, L-N; Ju, W-Y; Jin, F-L

    2016-12-01

    Insect defensins, are cationic peptides that play an important role in immunity against microbial infection. In the present study, an anionic defensin from Plutella xylostella, (designated as PxDef) was first cloned and characterized. Amino acid sequence analysis showed that the mature peptide owned characteristic six-cysteine motifs with predicted isoelectric point of 5.57, indicating an anionic defensin. Quantitative real-time polymerase chain reaction analysis showed that PxDef was significantly induced in epidermis, fat body, midgut and hemocytes after injection of heat-inactivated Bacillus thuringiensis, while such an induction was delayed by the injection of live B. thuringiensis in the 4th instar larvae of P. xylostella. Knocking down the expression of nuclear transcription factor Dorsal in P. xylostella by RNA interference significantly decreased the mRNA level of PxDef, and increased the sensitivity of P. xylostella larvae to the infection by live B. thuringiensis. The purified recombinant mature peptide (PxDef) showed higher activity against Gram-positive bacteria, with the minimum inhibition concentrations of 1.6 and 2.6 µM against B. thuringiensis and Bacillus subtilis, respectively. To our knowledge, this is the first report about an anionic PxDef, which may play an important role in the immune system of P. xylostella against B. thuringiensis.

  14. Anions coordinating anions: analysis of the interaction between anionic Keplerate nanocapsules and their anionic ligands.

    PubMed

    Melgar, Dolores; Bandeira, Nuno A G; Bonet Avalos, Josep; Bo, Carles

    2017-02-15

    Keplerates are a family of anionic metal oxide spherical capsules containing up to 132 metal atoms and some hundreds of oxygen atoms. These capsules holding a high negative charge of -12 coordinate both mono-anionic and di-anionic ligands thus increasing their charge up to -42, even up to -72, which is compensated by the corresponding counter-cations in the X-ray structures. We present an analysis of the relative importance of several energy terms of the coordinate bond between the capsule and ligands like carbonate, sulphate, sulphite, phosphinate, selenate, and a variety of carboxylates, of which the overriding component is contributed by solvation/de-solvation effects.

  15. Concentrating phenolic acids from Lonicera japonica by nanofiltration technology

    NASA Astrophysics Data System (ADS)

    Li, Cunyu; Ma, Yun; Li, Hongyang; Peng, Guoping

    2017-03-01

    Response surface analysis methodology was used to optimize the concentrate process of phenolic acids from Lonicera japonica by nanofiltration technique. On the basis of the influences of pressure, temperature and circulating volume, the retention rate of neochlorogenic acid, chlorogenic acid and 4-dicaffeoylquinic acid were selected as index, molecular weight cut-off of nanofiltration membrane, concentration and pH were selected as influencing factors during concentrate process. The experiment mathematical model was arranged according to Box-Behnken central composite experiment design. The optimal concentrate conditions were as following: nanofiltration molecular weight cut-off, 150 Da; solutes concentration, 18.34 µg/mL; pH, 4.26. The predicted value of retention rate was 97.99% under the optimum conditions, and the experimental value was 98.03±0.24%, which was in accordance with the predicted value. These results demonstrate that the combination of Box-Behnken design and response surface analysis can well optimize the concentrate process of Lonicera japonica water-extraction by nanofiltration, and the results provide the basis for nanofiltration concentrate for heat-sensitive traditional Chinese medicine.

  16. A randomized controlled study on the effects of acetate-free biofiltration on organic anions and acid-base balance in hemodialysis patients.

    PubMed

    Sánchez-Canel, Juan J; Hernández-Jaras, Julio; Pons-Prades, Ramón

    2015-02-01

    Metabolic acidosis correction is achieved by the transfer of bicarbonate and other buffer anions in dialysis. The aim of this study was to evaluate changes in the main anions of intermediary metabolism on standard hemodiafiltration (HDF) and on acetate-free biofiltration (AFB). A prospective, in-center, crossover study was carried out with 22 patients on maintenance dialysis. Patients were randomly assigned to start with 12 successive sessions of standard HDF with bicarbonate (34 mmol/L) and acetate dialysate (3 mmol/L) or 12 successive sessions of AFB without base in the dialysate. Acetate increased significantly during the standard HDF session from 0.078 ± 0.062 mmol/L to 0.156 ± 0.128 mmol/L (P < 0.05) and remained unchanged at 0.044 ± 0.034 mmol and 0.055 ± 0.028 mmol/L in AFB modality. Differences in the acetate levels were observed at two hours (P < 0.005), at the end (P < 0.005) and thirty minutes after the session between HDF and AFB (P < 0.05). There were significantly more patients above the normal range in HDF group than AFB group (68.1% vs 4.5% P < 0.005) postdialysis and 30 minutes later. Serum lactate and pyruvate concentrations decreased during the sessions without differences between modalities. Citrate decreased only in the AFB group (P < 0.05). Acetoacetate and betahydroxybutyrate increased in both modalities, but the highest betahydroxybutyrate values were detected in HDF (P < 0.05). The sum of postdialysis unusual measured organic anions (OA) were higher in HDF compared to AFB (P < 0.05). AFB achieves an optimal control of acid-base equilibrium through a bicarbonate substitution fluid. It also prevents hyperacetatemia and restores internal homeostasis with less production of intermediary metabolites. © 2014 The Authors. Therapeutic Apheresis and Dialysis © 2014 International Society for Apheresis.

  17. Synthetic cation-selective nanotube: permeant cations chaperoned by anions.

    PubMed

    Hilder, Tamsyn A; Gordon, Dan; Chung, Shin-Ho

    2011-01-28

    The ability to design ion-selective, synthetic nanotubes which mimic biological ion channels may have significant implications for the future treatment of bacteria, diseases, and as ultrasensitive biosensors. We present the design of a synthetic nanotube made from carbon atoms that selectively allows monovalent cations to move across and rejects all anions. The cation-selective nanotube mimics some of the salient properties of biological ion channels. Before practical nanodevices are successfully fabricated it is vital that proof-of-concept computational studies are performed. With this in mind we use molecular and stochastic dynamics simulations to characterize the dynamics of ion permeation across a single-walled (10, 10), 36 Å long, carbon nanotube terminated with carboxylic acid with an effective radius of 5.08 Å. Although cations encounter a high energy barrier of 7 kT, its height is drastically reduced by a chloride ion in the nanotube. The presence of a chloride ion near the pore entrance thus enables a cation to enter the pore and, once in the pore, it is chaperoned by the resident counterion across the narrow pore. The moment the chaperoned cation transits the pore, the counterion moves back to the entrance to ferry another ion. The synthetic nanotube has a high sodium conductance of 124 pS and shows linear current-voltage and current-concentration profiles. The cation-anion selectivity ratio ranges from 8 to 25, depending on the ionic concentrations in the reservoirs.

  18. Acetaminophen-induced anion gap metabolic acidosis and 5-oxoprolinuria (pyroglutamic aciduria) acquired in hospital.

    PubMed

    Humphreys, Benjamin D; Forman, John P; Zandi-Nejad, Kambiz; Bazari, Hasan; Seifter, Julian; Magee, Colm C

    2005-07-01

    A rare cause of high anion gap acidosis is 5-oxoproline (pyroglutamic acid), an organic acid intermediate of the gamma-glutamyl cycle. Acetaminophen and several other drugs have been implicated in the development of transient 5-oxoprolinemia in adults. We report the case of a patient with lymphoma who was admitted for salvage chemotherapy. The patient subsequently developed fever and neutropenia and was administered 20.8 g of acetaminophen during 10 days. During this time, anion gap increased from 14 to 30 mEq/L (14 to 30 mmol/L) and altered mental status developed. After usual causes of high anion gap acidosis were ruled out, a screen for urine organic acids showed 5-oxoproline levels elevated at 58-fold greater than normal values. Predisposing factors in this case included renal dysfunction and sepsis. Clinicians need to be aware of this unusual cause of anion gap acidosis because it may be more common than expected, early discontinuation of the offending agent is therapeutic, and administration of N -acetylcysteine could be beneficial.

  19. Inhibition of nuclear waste solutions containing multiple aggressive anions

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

    Congdon, J.W.

    1987-01-01

    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. 10more » refs., 5 figs., 2 tabs.« less

  20. Hydrothermal carbon nanosphere-based agglomerated anion exchanger for ion chromatography.

    PubMed

    Zhao, Qiming; Wu, Shuchao; Zhang, Kai; Lou, Chaoyan; Zhang, Peiming; Zhu, Yan

    2016-10-14

    This work reports the application of hydrothermal carbon nanospheres (HCNSs) as stationary phases in ion chromatography. HCNSs were facilely quaternized through polycondensation of methylamine and 1,4-butanediol diglycidyl ether. The quaternization was confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Owing to the electrostatic interaction, quaternized HCNSs were equably attached onto the surface of sulfonated polystyrene-divinylbenzene (PS-DVB) beads to construct the anion exchangers. The aggregation was verified by scanning electron microscopy and elemental analysis. Common anions, aliphatic monocarboxylic acids, polarizable anions, and aromatic acids were well separated on the stationary phases with good stability and symmetry. The prepared column was further applied to detect phosphate content in Cola drink samples. The limit of detection (S/N=3) was 0.09mg/L, and the relative standard deviation (n=10) of retention time was 0.31%. The average recovery was 99.58%. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Co-assembly of Peptide Amphiphiles and Lipids into Supramolecular Nanostructures Driven by Anion-π Interactions

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

    Yu, Zhilin; Erbas, Aykut; Tantakitti, Faifan

    Co-assembly of binary systems driven by specific non-covalent interactions can greatly expand the structural and functional space of supramolecular nanostructures. We report here on the self-assembly of peptide amphiphiles and fatty acids driven primarily by anion-π interactions. The peptide sequences investigated were functionalized with a perfluorinated phenylalanine residue to promote anion-π interactions with carboxylate headgroups in fatty acids. These interactions were verified here by NMR and circular dichroism experiments as well as investigated using atomistic simulations. Positioning the aromatic units close to the N-terminus of the peptide backbone near the hydrophobic core of cylindrical nanofibers leads to strong anion-π interactionsmore » between both components. With a low content of dodecanoic acid in this position, the cylindrical morphology is preserved. However, as the aromatic units are moved along the peptide backbone away from the hydrophobic core, the interactions with dodecanoic acid transform the cylindrical supramolecular morphology into ribbon-like structures. Increasing the ratio of dodecanoic acid to PA leads to either the formation of large vesicles in the binary systems where the anion-π interactions are strong, or a heterogeneous mixture of assemblies when the peptide amphiphiles associate weakly with dodecanoic acid. Our findings reveal how co-assembly involving designed specific interactions can drastically change supramolecular morphology and even cross from nano to micro scales.« less

  2. An anionic Na(i)-organic framework platform: separation of organic dyes and post-modification for highly sensitive detection of picric acid.

    PubMed

    Chen, Di-Ming; Tian, Jia-Yue; Wang, Zhuo-Wei; Liu, Chun-Sen; Chen, Min; Du, Miao

    2017-09-26

    A cage-based anionic Na(i)-organic framework with a unique Na 9 cluster-based secondary building unit and a cage-in-cage structure was constructed. The selective separation of dyes with different charges and sizes was investigated. Furthermore, the Rh6G@MOF composite could be applied as a recyclable fluorescent sensor for detecting picric acid (PA) with high sensitivity and selectivity.

  3. Loss of benzene to generate an enolate anion by a site-specific double-hydrogen transfer during CID fragmentation of o-alkyl ethers of ortho-hydroxybenzoic acids.

    PubMed

    Attygalle, Athula B; Bialecki, Jason B; Nishshanka, Upul; Weisbecker, Carl S; Ruzicka, Josef

    2008-09-01

    Collision-induced dissociation of anions derived from ortho-alkyloxybenzoic acids provides a facile way of producing gaseous enolate anions. The alkyloxyphenyl anion produced after an initial loss of CO(2) undergoes elimination of a benzene molecule by a double-hydrogen transfer mechanism, unique to the ortho isomer, to form an enolate anion. Deuterium labeling studies confirmed that the two hydrogen atoms transferred in the benzene loss originate from positions 1 and 2 of the alkyl chain. An initial transfer of a hydrogen atom from the C-1 position forms a phenyl anion and a carbonyl compound, both of which remain closely associated as an ion/neutral complex. The complex breaks either directly to give the phenyl anion by eliminating the neutral carbonyl compound, or to form an enolate anion by transferring a hydrogen atom from the C-2 position and eliminating a benzene molecule in the process. The pronounced primary kinetic isotope effect observed when a deuterium atom is transferred from the C-1 position, compared to the weak effect seen for the transfer from the C-2 position, indicates that the first transfer is the rate determining step. Quantum mechanical calculations showed that the neutral loss of benzene is a thermodynamically favorable process. Under the conditions used, only the spectra from ortho isomers showed peaks at m/z 77 for the phenyl anion and m/z 93 for the phenoxyl anion, in addition to that for the ortho-specific enolate anion. Under high collision energy, the ortho isomers also produce a peak at m/z 137 for an alkene loss. The spectra of meta and para compounds show a peak at m/z 92 for the distonic anion produced by the homolysis of the O-C bond. Moreover, a small peak at m/z 136 for a distonic anion originating from an alkyl radical loss allows the differentiation of para compounds from meta isomers.

  4. Spectroscopic studies on the antioxidant activity of p-coumaric acid.

    PubMed

    Kiliç, Ismail; Yeşiloğlu, Yeşim

    2013-11-01

    p-coumaric acid (4-hydroxycinnamic acid), a phenolic acid, is a hydroxyl derivative of cinnamic acid. It decreases low density lipoprotein (LDL) peroxidation and reduces the risk of stomach cancer. In vitro radical scavenging and antioxidant capacity of p-coumaric acid were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe(2+)) chelating activity and ferric ions (Fe(3+)) reducing ability. p-Coumaric acid inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45μg/mL concentration. On the other hand, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and ascorbic acid displayed 66.8%, 69.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, p-coumaric acid had an effective DPPH scavenging, ABTS(+) scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe(3+)) reducing power and ferrous ions (Fe(2+)) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that p-coumaric acid can be used in the pharmacological and food industry because of these properties. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Action of some foreign cations and anions on the chloride permeability of frog muscle

    PubMed Central

    Hutter, O. F.; Warner, Anne E.

    1967-01-01

    1. Evidence for the existence in skeletal muscle of a specific cation binding system capable of lowering the chloride permeability was obtained by testing the effect of several metal ion species upon the efflux of 36Cl from frog muscles equilibrated in high-KCl solution. 2. Cu2+, Zn2+ and UO22+ ions, when present in concentrations of approximately 10-4 M in inactive wash solution at pH 7·4 slowed the efflux of 36Cl to half its original value. At pH 5·0, when the chloride permeability was already low as a consequence of hydrogen ion binding, these metal ions had little further effect. 3. Presence of Ni2+, Co2+, Pb2+, Ce3+ and La3+ in 10-4 M or higher concentrations had no detectable influence on the 36Cl efflux. Wide variations in Ca2+ concentration were similarly ineffective. 4. The influence of more adsorbable anions on the chloride permeability was examined at different pH values. Extracellular iodide greatly slowed the rapid efflux of 36Cl into alkaline solution. In acid solutions, when the chloride permeability was already low, the effect of iodide was less pronounced, but still demonstrable. The chloride permeability was consequently increased to a lesser extent by a rise in pH in the presence of iodide. 5. The efflux of iodide and bromide was measured at different pH values under conditions of self exchange. In alkaline solution the permeabilities to iodide and bromide were considerably lower than that to chloride. In acid solution the membrane differentiated less between anion species of different adsorbability. PMID:6040156

  6. Anionic Four Electron Donor-Based Palladacycles as Catalysts for Addition Reactions of Arylboronic Acids with α,β-Unsaturated Ketones, Aldehydes and α-Ketoesters

    PubMed Central

    He, Ping; Lu, Yong; Dong, Cheng-Guo; Hu, Qiao-Sheng

    2008-01-01

    Anionic four electron donor-based palladacycle-catalyzed 1,4-additions of arylboronic acids with α,β-unsaturated ketones and 1,2-additions of arylboronic acids with aldehydes and α-ketoesters are described. Our study demonstrated that palladacycles were highly efficient, practical catalysts for these addition reactions. The work described here not only opened a new paradigm for the application of palladacycles, but may also pave the road for other metalacycles as practically useful catalysts for such addition reactions including asymmetric ones. PMID:17217300

  7. An interference-free glucose biosensor based on an anionic redox polymer-mediated enzymatic oxidation of glucose.

    PubMed

    Deng, Huimin; Shen, Wei; Gao, Zhiqiang

    2013-07-22

    Herein a novel strategy for the construction of an amperometric biosensor for highly sensitive and selective determination of glucose is described. The biosensor is made of a biocomposite membrane of glucose oxidase (GOx) and an Os(bpy)2 (bpy=2,2'-bipyridine)-based anionic redox polymer (Os-RP) mediator. The biosensor is fabricated through the co-immobilization of GOx and the Os-RP on the surface of a glassy carbon electrode by a simple one-step chemical crosslinking process. The crosslinked Os-RP/GOx composite membrane shows excellent catalytic activity toward the oxidation of glucose. Under optimal experimental conditions, a linear correlation between the oxidation current of glucose in amperometry at 0.25 V (vs. Ag/AgCl) and glucose concentration up to 10 mM with a sensitivity of 16.5 μA mM(-1) cm(-2) and a response time <5 s. Due to the presence of anionic sulfonic acid groups in the backbone of the redox polymer, the biosensor exhibits excellent selectivity to glucose in the presence of ascorbic acid and uric acid. The low hydrophobicity of the composite membrane also effectively retards the transport of molecular oxygen within the membrane. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. 21 CFR 146.148 - Reduced acid frozen concentrated orange juice.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... that the ratio of the Brix reading to the grams of acid, expressed as anhydrous citric acid, per 100... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Reduced acid frozen concentrated orange juice. 146... Canned Fruit Juices and Beverages § 146.148 Reduced acid frozen concentrated orange juice. (a) Reduced...

  9. 21 CFR 146.148 - Reduced acid frozen concentrated orange juice.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... that the ratio of the Brix reading to the grams of acid, expressed as anhydrous citric acid, per 100... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Reduced acid frozen concentrated orange juice. 146... Canned Fruit Juices and Beverages § 146.148 Reduced acid frozen concentrated orange juice. (a) Reduced...

  10. 21 CFR 146.148 - Reduced acid frozen concentrated orange juice.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... that the ratio of the Brix reading to the grams of acid, expressed as anhydrous citric acid, per 100... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Reduced acid frozen concentrated orange juice. 146... Canned Fruit Juices and Beverages § 146.148 Reduced acid frozen concentrated orange juice. (a) Reduced...

  11. 21 CFR 146.148 - Reduced acid frozen concentrated orange juice.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... that the ratio of the Brix reading to the grams of acid, expressed as anhydrous citric acid, per 100... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Reduced acid frozen concentrated orange juice. 146... Canned Fruit Juices and Beverages § 146.148 Reduced acid frozen concentrated orange juice. (a) Reduced...

  12. Surface properties and aggregate morphology of partially fluorinated carboxylate-type anionic gemini surfactants.

    PubMed

    Yoshimura, Tomokazu; Bong, Miri; Matsuoka, Keisuke; Honda, Chikako; Endo, Kazutoyo

    2009-11-01

    Three anionic homologues of a novel partially fluorinated carboxylate-type anionic gemini surfactant, N,N'-di(3-perfluoroalkyl-2-hydroxypropyl)-N,N'-diacetic acid ethylenediamine (2C(n)(F) edda, where n represents the number of carbon atoms in the fluorocarbon chain (4, 6, and 8)) were synthesized. In these present gemini surfactants, the relatively small carboxylic acid moieties form hydrophilic head groups. The surface properties or structures of the aggregates of these surfactants are strongly influenced by the nonflexible fluorocarbons and small head groups; this is because these surfactants have a closely packed molecular structure. The equilibrium surface tension properties of these surfactants were measured at 298.2K for various fluorocarbon chain lengths. The plot of the logarithm of the critical micelle concentration (cmc) against the fluorocarbon chain lengths for 2C(n)(F) edda (n=4, 6, and 8) showed a minimum for n=6. Furthermore, the lowest surface tension of 2C(6)(F) edda at the cmc was 16.4mNm(-1). Such unique behavior has not been observed even in the other fluorinated surfactants. Changes in the shapes and sizes of these surfactant aggregate with concentration were investigated by dynamic light scattering and transmission electron microscopy (TEM). The TEM micrographs showed that in an aqueous alkali solution, 2C(n)(F) edda mainly formed aggregates with stringlike (n=4), cagelike (n=6), and distorted bilayer structures (n=8). The morphological changes in the aggregates were affected by the molecular structure composed of nonflexible fluorocarbon chains and flexible hydrocarbon chains.

  13. Cation-enhanced capillary electrophoresis separation of atropoisomer anions.

    PubMed

    Na, Yun-Cheol; Berthod, Alain; Armstrong, Daniel W

    2015-12-01

    CE was used to study the separation of the atropoisomers of four phosphoric acids and two sulfonic acids and the enantiomers of two phosphoric acids. All solutes are in their anionic forms in aqueous electrolytes. The chiral additives were two hydroxypropyl cyclodextrins (CDs) and cyclofructan 6 (CF6). The CDs were able to separate four solutes and the CF6 additive could separate only one: 1,1'-binaphthyl-2,2'-diyl hydrogenphosphate (BHP). Since CF6 is able to bind with cations, nitrate of alkaline metals, Ba(2+) , and Pb(2+) were added, greatly improving the BHP separation at the expense of longer migration times. There seems to be a link between CF6-cation-binding constants and BHP resolution factors. Cation additions were also performed with CD selectors that are less prone to form complexes with cations. Significant improvements of enantiomer or atropoisomer separations were observed also associated with longer migration times. It is speculated that the anionic solutes associate with the added cations forming larger entities better differentiated by CDs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Acetaminophen-induced anion gap metabolic acidosis secondary to 5-oxoproline: a case report.

    PubMed

    Abkur, Tarig Mohammed; Mohammed, Waleed; Ali, Mohamed; Casserly, Liam

    2014-12-06

    5-oxoproline (pyroglutamic acid), an organic acid intermediate of the gamma-glutamyl cycle, is a rare cause of high anion gap metabolic acidosis. Acetaminophen and several other drugs have been implicated in the development of transient 5-oxoprolinemia in adults. We believe that reporting all cases of 5-oxoprolinemia will contribute to a better understanding of this disease. Here, we report the case of a patient who developed transient 5-oxoprolinemia following therapeutic acetaminophen use. A 75-year-old Caucasian woman was initially admitted for treatment of an infected hip prosthesis and subsequently developed transient high anion gap metabolic acidosis. Our patient received 40 g of acetaminophen over a 10-day period. After the more common causes of high anion gap metabolic acidosis were excluded, a urinary organic acid screen revealed a markedly increased level of 5-oxoproline. The acidosis resolved completely after discontinuation of the acetaminophen. 5-oxoproline acidosis is an uncommon cause of high anion gap metabolic acidosis; however, it is likely that it is under-diagnosed as awareness of the condition remains low and testing can only be performed at specialized laboratories. The diagnosis should be suspected in cases of anion gap metabolic acidosis, particularly in patients with recent acetaminophen use in combination with sepsis, malnutrition, liver disease, pregnancy or renal failure. This case has particular interest in medicine, especially for the specialties of nephrology and orthopedics. We hope that it will add more information to the literature about this rare condition.

  15. Anion exchange of organic carboxylate by soils responsible for positive Km-fc relationship from methanol mixture.

    PubMed

    Kim, Minhee; Han, Junho; Hyun, Seunghun

    2013-09-01

    The cosolvency model was not applicable for predicting the sorption of organic carboxylic acids. The reason of inapplicability was investigated by analyzing the solubility (Sm) and sorption (Km) of benzoic acid, 2,4-dichlorophenoxyacetic acid (2,4-D), and 2,4,6-trichlorophenol (2,4,6-TCP). The Sm and Km by two iron-rich soils was measured as a function of methanol volume fraction (fc), electrolyte compositions, and pH(app). For 2,4,6-TCP, the Km of both neutral and anion species was well-explainable by the cosolvency model, exemplifying the knowledge of cosolvency power (σ) being sufficient to describe its sorption. However, for benzoic acid and 2,4-D, the Km of organic anions increased with fc, illustrating the organic carboxylate to be responsible for the deviation. The Sm of organic anions was not affected by the ionic valence (Ca(2+) vs. K(+)) of liquid phase. Among hydrophilic quantities of the 2,4-D sorption, the fraction of anion exchange increased with fc while the fraction of Ca-bridge decreased in the same range. Adding solvent in soil-water system is likely to render soil surface charge more positive, fortifying the anion exchange, but opposing the formation of Ca-bridging. Therefore, it can be concluded that the positive Km-fc relationship is due to the anion exchange of organic carboxylate with positively charged soil surface, whose contribution is >50% of overall sorption at solvent-free system and becomes greater with fc up to 82%. Copyright © 2013. Published by Elsevier Ltd.

  16. Neutral and anionic duality of 1,2,4-triazole α-amino acid scaffold in 1D coordination polymers

    NASA Astrophysics Data System (ADS)

    Naik, Anil D.; Dîrtu, Marinela M.; Garcia, Yann

    2012-03-01

    A tiny supramolecular synthon, 4H-1,2,4-triazol-4-yl acetic acid (HGlytrz) which is bifunctional by design having an electronic asymmetry and conformational flexibility has been introduced to synthesize iron(II) complexes. Having 1,2,4-triazole or carboxylic extremities on the same framework HGlytrz could display dual functionality by acting as a neutral as well as anionic ligand based on the possibility of deprotonation of carboxylic group. Four new iron(II) HGlytrz complexes with ClO4- ( 1), NO3- ( 2), BF4- ( 3) and CF3SO3- ( 4) anions were prepared. Formulation of their composition which is complicated due to ligand deprotonation is discussed. Unlike its ester protected counterpart ethyl-4H-1,2,4-triazol-4-yl-acetate ( αGlytrz) which show hysteretic room temperature spin crossover, 1- 4 remain in the high-spin state as revealed by 57Mössbauer spectroscopy. Prospects of such 1D coordination polymers with dangling unbounded carboxylic entities in the realm of self-assembled monolayer (SAM) are discussed.

  17. Self-exchange reactions of radical anions in n-hexane.

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

    Werst, D. W.; Chemistry

    The formation and reactions of radical anions in n-hexane at 190 K were investigated by pulse radiolysis and time-resolved fluorescence-detected magnetic resonance (FDMR). Electron attachment was found to occur for compounds with gas-phase electron affinities (EA) more positive than -1.1 {+-} 0.1 eV. The FDMR concentration and time dependence are interpreted as evidence for self-exchange electron-transfer reactions, indicating that formation of dimer radical anions is not prevalent for the range of molecules studied. FDMR detection of radical anions is mainly restricted to electron acceptors with EA less than approximately 0.5 eV.

  18. Adsorption mechanism of mixed cationic/anionic collectors in feldspar-quartz flotation system.

    PubMed

    Vidyadhar, A; Hanumantha Rao, K

    2007-02-15

    The adsorption mechanism of mixed cationic alkyl diamine and anionic sulfonate/oleate collectors at acidic pH values was investigated on microcline and quartz minerals through Hallimond flotation, electrokinetic and diffuse reflectance FTIR studies. In the presence of anionic collectors, neither of the minerals responded to flotation but the diamine flotation of the minerals was observed to be pH and concentration dependent. The presence of sulfonate enhanced the diamine flotation of the minerals by its co-adsorption. The difference in surface charge between the minerals at pH 2 was found to be the basis for preferential feldspar flotation from quartz in mixed diamine/sulfonate collectors. The infrared spectra revealed no adsorption of sulfonate collector when used alone but displayed its co-adsorption as diamine-sulfonate complex when used with diamine. The presence of sulfonate increased the diamine adsorption due to a decrease in the electrostatic head-head repulsion between the adjacent surface ammonium ions and thereby increasing the lateral tail-tail hydrophobic bonds. The mole ratio of diamine/sulfonate was found to be an important factor in the orientation of alkyl chains and thus the flotation response of minerals. The increase in sulfonate concentration beyond diamine concentration leads to the formation of soluble 1:2 diamine-sulfonate complex or precipitate and the adsorption of these species decreased the flotation since the alkyl chains are in chaotical orientation with a conceivable number of head groups directing towards the solution phase.

  19. Experimental and theoretical elucidation of structural and antioxidant properties of vanillylmandelic acid and its carboxylate anion

    NASA Astrophysics Data System (ADS)

    Dimić, Dušan; Milenković, Dejan; Ilić, Jelica; Šmit, Biljana; Amić, Ana; Marković, Zoran; Dimitrić Marković, Jasmina

    2018-06-01

    Vanillylmandelic acid (VMA), an important metabolite of catecholamines that is routinely screened as tumor marker, was investigated by the various spectroscopic techniques (IR, Raman, UV-Vis, antioxidant decolorization assay and NMR). Structures optimized by the employment of five common functionals (M05-2X, M06-2X, B3LYP, CAM-B3LYP, B3LYP-D3) were compared with the crystallographic data. The M05-2X functional reproduced the most reliable experimental bond lengths and angles (correlation coefficient >0.999). The importance of intramolecular hydrogen bonds for structural stability was discussed and quantified by the NBO analysis. The most prominent bands in vibrational spectrum were analyzed and compared to the experimental data. The positions of the carbon and hydrogen atoms in NMR spectra were well reproduced. The differences in UV-Vis spectrum were investigated by adding the explicit solvent and by performing NBO and QTAIM analyses. The discrepancy in the two spectra of about 50 nm could be explained by the solvent effect on carboxyl group. The most probable antioxidant activity mechanism was discussed for VMA and its carboxylate anion. The Molecular Docking study with the C - reactive protein additionally proved that variety of functional groups present in VMA and its anion allowed strong hydrogen and hydrophobic interactions.

  20. Structure and in vitro activities of a Copper II-chelating anionic peptide from the venom of the scorpion Tityus stigmurus.

    PubMed

    Melo, Menilla M A; Daniele-Silva, Alessandra; Teixeira, Diego G; Estrela, Andréia B; Melo, Karolline R T; Oliveira, Verônica S; Rocha, Hugo A O; Ferreira, Leandro de Santis; Pontes, Daniel L; Lima, João P M S; Silva-Júnior, Arnóbio A; Barbosa, Euzebio G; Carvalho, Eneas; Fernandes-Pedrosa, Matheus F

    2017-08-01

    Anionic Peptides are molecules rich in aspartic acid (Asp) and/or glutamic acid (Glu) residues in the primary structure. This work presents, for the first time, structural characterization and biological activity assays of an anionic peptide from the venom of the scorpion Tityus stigmurus, named TanP. The three-dimensional structure of TanP was obtained by computational modeling and refined by molecular dynamic (MD) simulations. Furthermore, we have performed circular dichroism (CD) analysis to predict TanP secondary structure, and UV-vis spectroscopy to evaluate its chelating activity. CD indicated predominance of random coil conformation in aqueous medium, as well as changes in structure depending on pH and temperature. TanP has chelating activity on copper ions, which modified the peptide's secondary structure. These results were corroborated by MD data. The molar ratio of binding (TanP:copper) depends on the concentration of peptide: at lower TanP concentration, the molar ratio was 1:5 (TanP:Cu 2+ ), whereas in concentrated TanP solution, the molar ratio was 1:3 (TanP:Cu 2+ ). TanP was not cytotoxic to non-neoplastic or cancer cell lines, and showed an ability to inhibit the in vitro release of nitric oxide by LPS-stimulated macrophages. Altogether, the results suggest TanP is a promising peptide for therapeutic application as a chelating agent. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Cadmium Alters the Concentration of Fatty Acids in THP-1 Macrophages.

    PubMed

    Olszowski, Tomasz; Gutowska, Izabela; Baranowska-Bosiacka, Irena; Łukomska, Agnieszka; Drozd, Arleta; Chlubek, Dariusz

    2018-03-01

    Fatty acid composition of human immune cells influences their function. The aim of this study was to evaluate the effects of known toxicant and immunomodulator, cadmium, at low concentrations on levels of selected fatty acids (FAs) in THP-1 macrophages. The differentiation of THP-1 monocytes into macrophages was achieved by administration of phorbol myristate acetate. Macrophages were incubated with various cadmium chloride (CdCl 2 ) solutions for 48 h at final concentrations of 5 nM, 20 nM, 200 nM, and 2 μM CdCl 2 . Fatty acids were extracted from samples according to the Folch method. The fatty acid levels were determined using gas chromatography. The following fatty acids were analyzed: long-chain saturated fatty acids (SFAs) palmitic acid and stearic acid, very long-chain saturated fatty acid (VLSFA) arachidic acid, monounsaturated fatty acids (MUFAs) palmitoleic acid, oleic acid and vaccenic acid, and n-6 polyunsaturated fatty acids (PUFAs) linoleic acid and arachidonic acid. Treatment of macrophages with very low concentrations of cadmium (5-200 nM) resulted in significant reduction in the levels of arachidic, palmitoleic, oleic, vaccenic, and linoleic acids and significant increase in arachidonic acid levels (following exposure to 5 nM Cd), without significant reduction of palmitic and stearic acid levels. Treatment of macrophages with the highest tested cadmium concentration (2 μM) produced significant reduction in the levels of all examined FAs: SFAs, VLSFA, MUFAs, and PUFAs. In conclusion, cadmium at tested concentrations caused significant alterations in THP-1 macrophage fatty acid levels, disrupting their composition, which might dysregulate fatty acid/lipid metabolism thus affecting macrophage behavior and inflammatory state.

  2. Interaction of the Spo20 membrane-sensor motif with phosphatidic acid and other anionic lipids, and influence of the membrane environment.

    PubMed

    Horchani, Habib; de Saint-Jean, Maud; Barelli, Hélène; Antonny, Bruno

    2014-01-01

    The yeast protein Spo20 contains a regulatory amphipathic motif that has been suggested to recognize phosphatidic acid, a lipid involved in signal transduction, lipid metabolism and membrane fusion. We have investigated the interaction of the Spo20 amphipathic motif with lipid membranes using a bioprobe strategy that consists in appending this motif to the end of a long coiled-coil, which can be coupled to a GFP reporter for visualization in cells. The resulting construct is amenable to in vitro and in vivo experiments and allows unbiased comparison between amphipathic helices of different chemistry. In vitro, the Spo20 bioprobe responded to small variations in the amount of phosphatidic acid. However, this response was not specific. The membrane binding of the probe depended on the presence of phosphatidylethanolamine and also integrated the contribution of other anionic lipids, including phosphatidylserine and phosphatidyl-inositol-(4,5)bisphosphate. Inverting the sequence of the Spo20 motif neither affected the ability of the probe to interact with anionic liposomes nor did it modify its cellular localization, making a stereo-specific mode of phosphatidic acid recognition unlikely. Nevertheless, the lipid binding properties and the cellular localization of the Spo20 alpha-helix differed markedly from that of another amphipathic motif, Amphipathic Lipid Packing Sensor (ALPS), suggesting that even in the absence of stereo specific interactions, amphipathic helices can act as subcellular membrane targeting determinants in a cellular context.

  3. Solvent and H/D isotope effects on the proton transfer pathways in heteroconjugated hydrogen-bonded phenol-carboxylic acid anions observed by combined UV-vis and NMR spectroscopy.

    PubMed

    Koeppe, Benjamin; Guo, Jing; Tolstoy, Peter M; Denisov, Gleb S; Limbach, Hans-Heinrich

    2013-05-22

    Heteroconjugated hydrogen-bonded anions A···H···X(-) of phenols (AH) and carboxylic/inorganic acids (HX) dissolved in CD2Cl2 and CDF3/CDF2Cl have been studied by combined low-temperature UV-vis and (1)H/(13)C NMR spectroscopy (UVNMR). The systems constitute small molecular models of hydrogen-bonded cofactors in proteins such as the photoactive yellow protein (PYP). Thus, the phenols studied include the PYP cofactor 4-hydroxycinnamic acid methyl thioester, and the more acidic 4-nitrophenol and 2-chloro-4-nitrophenol which mimic electronically excited cofactor states. It is shown that the (13)C chemical shifts of the phenolic residues of A···H···X(-), referenced to the corresponding values of A···H···A(-), constitute excellent probes for the average proton positions. These shifts correlate with those of the H-bonded protons, as well as with the H/D isotope effects on the (13)C chemical shifts. A combined analysis of UV-vis and NMR data was employed to elucidate the proton transfer pathways in a qualitative way. Dual absorption bands of the phenolic moiety indicate a double-well situation for the shortest OHO hydrogen bonds studied. Surprisingly, when the solvent polarity is low the carboxylates are protonated whereas the proton shifts toward the phenolic oxygens when the polarity is increased. This finding indicates that because of stronger ion-dipole interactions small anions are stabilized at high solvent polarity and large anions exhibiting delocalized charges at low solvent polarities. It also explains the large acidity difference of phenols and carboxylic acids in water, and the observation that this difference is strongly reduced in the interior of proteins when both partners form mutual hydrogen bonds.

  4. Structures and energetics of hydrated deprotonated cis-pinonic acid anion clusters and their atmospheric relevance

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

    Hou, Gao-Lei; Zhang, Jun; Valiev, Marat

    2017-01-01

    Pinonic acid, a C10-monocarboxylic acid with a hydrophilic –CO 2H group and a hydrophobic hydrocarbon backbone, is a key intermediate oxidation product of α-pinene – an important monoterpene compound in biogenic emission processes that influences the atmosphere. Molecular interaction between cis-pinonic acid and water is essential for understanding its role in the formation and growth of pinene-derived secondary organic aerosols. In this work, we studied the structures, energetics, and optical properties of hydrated clusters of cis-pinonate anion (cPA–), the deprotonated form of cis-pinonic acid, by negative ion photoelectron spectroscopy and ab initio theoretical calculations. Our results show that cPA– canmore » adopt two different structural configurations – open and folded. In the absence of waters, the open configuration has the lowest energy and provides the best agreement with the experiment. The addition waters, which mainly interact with the negatively charged -CO 2– group, gradually stabilize the folded configuration and lower its energy difference relative to the most stable open-configured structure. Thermochemical and equilibrium hydrate distribution analysis suggests that the mono- and di- hydrates are likely to exist in humid atmospheric environment with high populations. The detailed molecular description of cPA– hydrated clusters unraveled in this study provides a valuable reference for understanding the initial nucleation process and aerosol formation involving organics containing both hydrophilic and hydrophobic groups, as well as for analyzing the optical properties of those organic aerosols.« less

  5. Process for separating and recovering an anionic dye from an aqueous solution

    DOEpatents

    Rogers, Robin; Horwitz, E. Philip; Bond, Andrew H.

    1998-01-01

    A solid/liquid phase process for the separation and recovery of an anionic dye from an aqueous solution is disclosed. The solid phase comprises separation particles having surface-bonded poly(ethylene glycol) groups, whereas the aqueous solution from which the anionic dye molecules are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved lyotropic salt. After contact between the aqueous solution and separation particles, the anionic dye is bound to the particles. The bound anionic dye molecules are freed from the separation particles by contacting the anionic dye-bound particles with an aqueous solution that does not contain a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved lyotropic salt to form an aqueous anionic dye solution whose anionic dye concentration is preferably higher than that of the initial dye-containing solution.

  6. Process for separating and recovering an anionic dye from an aqueous solution

    DOEpatents

    Rogers, R.; Horwitz, E.P.; Bond, A.H.

    1998-01-13

    A solid/liquid phase process for the separation and recovery of an anionic dye from an aqueous solution is disclosed. The solid phase comprises separation particles having surface-bonded poly(ethylene glycol) groups, whereas the aqueous solution from which the anionic dye molecules are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved lyotropic salt. After contact between the aqueous solution and separation particles, the anionic dye is bound to the particles. The bound anionic dye molecules are freed from the separation particles by contacting the anionic dye-bound particles with an aqueous solution that does not contain a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved lyotropic salt to form an aqueous anionic dye solution whose anionic dye concentration is preferably higher than that of the initial dye-containing solution. 7 figs.

  7. Effect of Hydrochloric Acid Concentration on the Conversion of Sugarcane Bagasse to Levulinic Acid

    NASA Astrophysics Data System (ADS)

    Anggorowati, Heni; Jamilatun, Siti; Cahyono, Rochim B.; Budiman, Arief

    2018-01-01

    Levulinic acid is a new green platform chemical used to the synthesis of a variety of materials for numerous applications such as fuel additives, polymers and resins. It can be produced using renewable resources such as biomass like sugarcane bagasse which are cheap and widely available as waste in Indonesia. In this study, sugarcane bagasse was hydrolyzed using hydrochloric acid with a solid liquid ratio 1:10. The effects of hydrochloric acid concentration at temperature of 180 °C and reaction time of 30 min were studied. The presence of levulinic acid in product of hydrolysis was measured with gas chromatography (GC). It was found that the highest concentration of levulinic acid was obtained at 1 M hydrochloric acid in 25.56 yield%.

  8. Anion binding in biological systems

    NASA Astrophysics Data System (ADS)

    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.

  9. Effect of a commercial anion dietary supplement on acid-base balance, urine volume, and urinary ion excretion in male goats fed oat or grass hay diets.

    PubMed

    Stratton-Phelps, Meri; House, John K

    2004-10-01

    To determine whether feeding a commercial anionic dietary supplement as a urinary acidifier to male goats may be useful for management of urolithiasis. 8 adult sexually intact male Toggenburg, Saanen, and Nubian goats. Goats were randomly assigned by age-, breed-, and weight-matched pairs to an oat or grass hay diet that was fed for 12 days. On days 13 to 14 (early sample collection time before supplementation), measurements were made of blood and urine sodium, potassium, calcium, magnesium, chloride, phosphorus, and sulfur concentrations; blood and urine pH; urine production; and water consumption. During the next 28 days, the anionic dietary supplement was added to the oat and grass hay diets to achieve a dietary cation-anion difference of 0 mEq/100g of dry matter. Blood and urine samples were analyzed during dietary supplementation on days 12 to 13 (middle sample collection time) and 27 to 28 (late sample collection time). Blood bicarbonate, pH, and urine pH of goats fed grass hay and goats fed oat hay were significantly decreased during the middle and late sample collection times, compared with the early sample collection time. Water consumption and urine production in all goats increased significantly during the late sample collection time, compared with the early sample collection time. The anionic dietary supplement used in our study increases urine volume, alters urine ion concentrations, and is an efficacious urinary acidifier in goats. Goats treated with prolonged anionic dietary supplementation should be monitored for secondary osteoporosis from chronic urinary calcium loss.

  10. Composition and stability of complexes of maleic and succinic acids with Cu2+ ions in water-ethanol solutions at 298 K

    NASA Astrophysics Data System (ADS)

    Tukumova, N. V.; Usacheva, T. R.; Thuan, Tran Thi Dieu; Sharnin, V. A.

    2014-10-01

    The composition and stability of coordination compounds of the anions of maleic (H2L) and succinic (H2Y) acids with copper(II) ions in water-ethanol solutions is studied by means of potentiometric titration at a sodium perchlorate ionic strength of 0.1 and a temperature of 298.15 K. The composition of the water-ethanol solvent was varied from 0 to 0.7 molar parts of ethanol for maleic acid and from 0 to 0.4 molar parts for succinic acid. The stability of monoligand complexes of copper ions with the anions of maleic and succinic acids grows with increase of ethanol concentration from 3.86 to 6.62 for logβCuL and from 2.98 to 6.01 for logβCuY. It is shown that a monotonic rise in stability upon an increase in the content of ethanol in solution is observed, while the values of logβCuL change more sharply. The succinic acid anion forms a stronger complex with copper ions than maleic acid anions do at an ethanol content of 0.4 molar parts. The possibility of the formation of a protonated CuHY+ particle is established.

  11. Re-entrant phase behavior of a concentrated anionic surfactant system with strongly binding counterions.

    PubMed

    Ghosh, Sajal Kumar; Rathee, Vikram; Krishnaswamy, Rema; Raghunathan, V A; Sood, A K

    2009-08-04

    The phase behavior of the anionic surfactant sodium dodecyl sulfate (SDS) in the presence of the strongly binding counterion p-toluidine hydrochloride (PTHC) has been examined using small-angle X-ray diffraction and polarizing microscopy. A hexagonal-to-lamellar transition on varying the PTHC to SDS molar ratio (alpha) occurs through a nematic phase of rodlike micelles (Nc) --> isotropic (I) --> nematic of disklike micelles (N(D)) at a fixed surfactant concentration (phi). The lamellar phase is found to coexist with an isotropic phase (I') over a large region of the phase diagram. Deuterium nuclear magnetic resonance investigations of the phase behavior at phi = 0.4 confirm the transition from N(C) to N(D) on varying alpha. The viscoelastic and flow behaviors of the different phases were examined. A decrease in the steady shear viscosity across the different phases with increasing alpha suggests a decrease in the aspect ratio of the micellar aggregates. From the transient shear stress response of the N() and N(D) nematic phases in step shear experiments, they were characterized to be tumbling and flow aligning, respectively. Our studies reveal that by tuning the morphology of the surfactant micelles strongly binding counterions modify the phase behavior and rheological properties of concentrated surfactant solutions.

  12. Experimental IR and Raman spectra and quantum chemical studies of molecular structures, conformers and vibrational characteristics of L-ascorbic acid and its anion and cation

    NASA Astrophysics Data System (ADS)

    Yadav, R. A.; Rani, P.; Kumar, M.; Singh, R.; Singh, Priyanka; Singh, N. P.

    2011-12-01

    IR and spectra of the L-ascorbic acid ( L-AA) also known as vitamin C have been recorded in the region 4000-50 cm -1. In order to make vibrational assignments of the observed IR and Raman bands computations were carried out by employing the RHF and DFT methods to calculate the molecular geometries and harmonic vibrational frequencies along with other related parameters for the neutral L-AA and its singly charged anionic ( L-AA -) and cationic ( L-AA +) species. Significant changes have been found for different characteristics of a number of vibrational modes. The four ν(O-H) modes of the L-AA molecule are found in the order ν(O 9-H 10) > ν(O 19-H 20) > ν(O 7-H 8) > ν(O 14-H 15) which could be due to complexity of hydrogen bonding in the lactone ring and the side chain. The C dbnd O stretching wavenumber ( ν46) decreases by 151 cm -1 in going from the neutral to the anionic species whereas it increases by 151 cm -1 in going from the anionic to the cationic species. The anionic radicals have less kinetic stabilities and high chemical reactivity as compared to the neutral molecule. It is found that the cationic radical of L-AA is kinetically least stable and chemically most reactive as compared to its neutral and anionic species.

  13. Anion exchange membrane

    DOEpatents

    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.

  14. An anion channel in Arabidopsis hypocotyls activated by blue light

    NASA Technical Reports Server (NTRS)

    Cho, M. H.; Spalding, E. P.; Evans, M. L. (Principal Investigator)

    1996-01-01

    A rapid, transient depolarization of the plasma membrane in seedling stems is one of the earliest effects of blue light detected in plants. It appears to play a role in transducing blue light into inhibition of hypocotyl (stem) elongation, and perhaps other responses. The possibility that activation of a Cl- conductance is part of the depolarization mechanism was raised previously and addressed here. By patch clamping hypocotyl cells isolated from dark-grown (etiolated) Arabidopsis seedlings, blue light was found to activate an anion channel residing at the plasma membrane. An anion-channel blocker commonly known as NPPB 15-nitro-2-(3-phenylpropylamino)-benzoic acid] potently and reversibly blocked this anion channel. NPPB also blocked the blue-light-induced depolarization in vivo and decreased the inhibitory effect of blue light on hypocotyl elongation. These results indicate that activation of this anion channel plays a role in transducing blue light into growth inhibition.

  15. Metabolomic profiling of anionic metabolites by capillary electrophoresis mass spectrometry.

    PubMed

    Soga, Tomoyoshi; Igarashi, Kaori; Ito, Chiharu; Mizobuchi, Katsuo; Zimmermann, Hans-Peter; Tomita, Masaru

    2009-08-01

    We describe a sheath flow capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS) method in the negative mode using a platinum electrospray ionization (ESI) spray needle, which allows the comprehensive analysis of anionic metabolites. The material of the spray needle had significant effect on the measurement of anions. A stainless steel spray needle was oxidized and corroded at the anodic electrode due to electrolysis. The precipitation of iron oxides (rust) plugged the capillary outlet, resulting in shortened capillary lifetime. Many anionic metabolites also formed complexes with the iron oxides or migrating nickel ion, which was also generated by electrolysis and moved toward the cathode (the capillary inlet). The metal-anion complex formation significantly reduced detection sensitivity of the anionic compounds. The use of a platinum ESI needle prevented both oxidation of the metals and needle corrosion. Sensitivity using the platinum needle increased from several- to 63-fold, with the largest improvements for anions exhibiting high metal chelating properties such as carboxylic acids, nucleotides, and coenzyme A compounds. The detection limits for most anions were between 0.03 and 0.87 micromol/L (0.8 and 24 fmol) at a signal-to-noise ratio of 3. This method is quantitative, sensitive, and robust, and its utility was demonstrated by the analysis of the metabolites in the central metabolic pathways extracted from mouse liver.

  16. Determination of the dissolved anion composition of ancient lakes from fossil ostracodes.

    USGS Publications Warehouse

    Forester, R.M.

    1986-01-01

    The mineralogy of evaporite and other precipitated minerals has provided traditional sources of information about the major dissolved ion composition of ancient lakes. The paleocompositional resolving power of these methods is generally greatest in high-salinity lakes. Ostracodes live in dilute saline lakes where a species occurrence is determined by the relative proportions of the lake's major dissolved anions, so that each species describes specific areas on an anion trilinear diagram. The upper salinity tolerance of each species depends upon the types of major anions in solution and is therefore anion-specific. Knowledge about both anion and anion-salinity tolerances of an ostracode may ultimately provide a means of estimating absolute anion concentrations in paleolakes. Because ostracodes are common fossils in lake sediments, they provide an important new source of original paleocompositional information suitable for many geologic, climatic, geochemical, and paleontologic studies. -from Author

  17. Nectar sugars and amino acids in day- and night-flowering Nicotiana species are more strongly shaped by pollinators' preferences than organic acids and inorganic ions.

    PubMed

    Tiedge, Kira; Lohaus, Gertrud

    2017-01-01

    Floral nectar contains mainly sugars but also amino acids, organic acids, inorganic ions and secondary compounds to attract pollinators. The genus Nicotiana exhibits great diversity among species in floral morphology, flowering time, nectar compositions, and predominant pollinators. We studied nectar samples of 20 Nicotiana species, composed equally of day- and night-flowering plants and attracting different groups of pollinators (e.g. hummingbirds, moths or bats) to investigate whether sugars, amino acids, organic acids and inorganic ions are influenced by pollinator preferences. Glucose, fructose and sucrose were the only sugars found in the nectar of all examined species. Sugar concentration of the nectar of day-flowering species was 20% higher and amino acid concentration was 2-3-fold higher compared to the nectar of night-flowering species. The sucrose-to-hexose ratio was significantly higher in night-flowering species and the relative share of sucrose based on the total sugar correlated with the flower tube length in the nocturnal species. Flowers of different tobacco species contained varying volumes of nectar which led to about 150-fold higher amounts of total sugar per flower in bat- or sunbird-pollinated species than in bee-pollinated or autogamous species. This difference was even higher for total amino acids per flower (up to 1000-fold). As a consequence, some Nicotiana species invest large amounts of organic nitrogen for certain pollinators. Higher concentrations of inorganic ions, predominantly anions, were found in nectar of night-flowering species. Therefore, higher anion concentrations were also associated with pollinator types active at night. Malate, the main organic acid, was present in all nectar samples but the concentration was not correlated with pollinator type. In conclusion, statistical analyses revealed that pollinator types have a stronger effect on nectar composition than phylogenetic relations. In this context, nectar sugars and amino

  18. Nectar sugars and amino acids in day- and night-flowering Nicotiana species are more strongly shaped by pollinators’ preferences than organic acids and inorganic ions

    PubMed Central

    Tiedge, Kira; Lohaus, Gertrud

    2017-01-01

    Floral nectar contains mainly sugars but also amino acids, organic acids, inorganic ions and secondary compounds to attract pollinators. The genus Nicotiana exhibits great diversity among species in floral morphology, flowering time, nectar compositions, and predominant pollinators. We studied nectar samples of 20 Nicotiana species, composed equally of day- and night-flowering plants and attracting different groups of pollinators (e.g. hummingbirds, moths or bats) to investigate whether sugars, amino acids, organic acids and inorganic ions are influenced by pollinator preferences. Glucose, fructose and sucrose were the only sugars found in the nectar of all examined species. Sugar concentration of the nectar of day-flowering species was 20% higher and amino acid concentration was 2-3-fold higher compared to the nectar of night-flowering species. The sucrose-to-hexose ratio was significantly higher in night-flowering species and the relative share of sucrose based on the total sugar correlated with the flower tube length in the nocturnal species. Flowers of different tobacco species contained varying volumes of nectar which led to about 150-fold higher amounts of total sugar per flower in bat- or sunbird-pollinated species than in bee-pollinated or autogamous species. This difference was even higher for total amino acids per flower (up to 1000-fold). As a consequence, some Nicotiana species invest large amounts of organic nitrogen for certain pollinators. Higher concentrations of inorganic ions, predominantly anions, were found in nectar of night-flowering species. Therefore, higher anion concentrations were also associated with pollinator types active at night. Malate, the main organic acid, was present in all nectar samples but the concentration was not correlated with pollinator type. In conclusion, statistical analyses revealed that pollinator types have a stronger effect on nectar composition than phylogenetic relations. In this context, nectar sugars and amino

  19. Altered fatty acid concentrations in prefrontal cortex of schizophrenic patients

    PubMed Central

    Taha, Ameer Y.; Cheon, Yewon; Ma, Kaizong; Rapoport, Stanley I.; Rao, Jagadeesh S.

    2013-01-01

    Background Disturbances in prefrontal cortex phospholipid and fatty acid composition have been reported in schizophrenic (SCZ) patients, often as percent of total lipid concentration or incomplete lipid profile. In this study, we quantified absolute concentrations (nmol/g wet weight) of several lipid classes and their constituent fatty acids in postmortem prefrontal cortex of SCZ patients (n = 10) and age-matched controls (n = 10). Methods Lipids were extracted, fractionated with thin layer chromatography and assayed. Results Mean total lipid, phospholipid, individual phospholipids, plasmalogen, triglyceride and cholesteryl ester concentrations did not differ significantly between the groups. Compared to controls, SCZ brains showed significant increases in several monounsaturated and polyunsaturated fatty acids in cholesteryl ester. Significant increases or decreases occurred in palmitoleic, linoleic, γ-linolenic and n-3 docosapentaenoic acid in total lipids, triglycerides or phospholipids. Conclusion These changes suggest disturbed prefrontal cortex fatty acid concentrations, particularly within cholesteryl esters, as a pathological aspect of schizophrenia. PMID:23428160

  20. Organotin-mediated exchange diffusion of anions in human red cells

    PubMed Central

    1979-01-01

    Organotin cations (R3Sn+) form electrically neutral ion pairs with monovalent anions. It is demonstrated that the tin derivatives induce exchange diffusion of chloride in red cells and resealed ghosts, without any detectable increase of membrane permeability to net movements of chloride ions. The obligatory anion exchange is believed to be due to the permeation of electroneural ion pairs, whereas the organic cation (R3Sn+) has an extremely low membrane permeability. Exchange fluxes of chloride increased with the lipophilicity of the substituting group (R3). At the same molar concentration of organotin, the relative potencies of the tin derivatives as anion carriers (with trimethyltin as a reference) were: methyl 1, ethyl 30, propyl = phenyl 1,00, and butyl 10,000. Tributyltin-mediated anion exchange was studied in detail. The organotin-induced anion transport increased through the sequence: F- less than Cl- less than Br- less than I- = SCN- less than OH-. Partitioning of tributyltin into red cell membranes was greater in iodide than in chloride media (partition coefficients 6.6 and 1.7 x 10(- 3) cm, respectively). Bicarbonate, fluoride, nitrate, phosphate, and sulphate did not exchange with chloride in the presence of tributyltin. Chloride exchange fluxes increased linearly with tributylin concentrations up to 10(-5) M, and with chloride concentrations up to at least 0.9 M. The apparent turnover number for tributyltin-mediated chloride exchange increased from 15 to 1,350 s-1 between 0 and 38 degrees C. These figures are minimum turnover numbers, because it is not known what fraction of the organotin in the membrane exists as chloride ion pairs. PMID:479814

  1. Environmental management of acid water problems in mining areas

    NASA Astrophysics Data System (ADS)

    Singh, Gurdeep; Bhatnagar, Mridula; Sinha, D. K.

    1990-03-01

    Acid Mine Drainage (AMD) originates from the oxidation and leaching of sulphide minerals present in coal and metalliferrous ore bodies and gives rise to several environmental degradation problems. An investigation has been carried out to combat the acidic water problems. Results of this investigation indicate that application of anionic surfactant (sodium lauryl sulphate) and food preservatives (sodium benzoate and potassium sorbate) effectively abate the acid formation at low concentration levels (15-40 ppm) as tested in laboratory as well as at pilot-scale levels. Acidity, sulphate and iron concentrations are found to reduce by over 70 percent and remained low for more than three months after treatment. Thus this investigation demonstrates the management of these problems in an environmentally safe manner by controlling acid formation at its source.

  2. Concentrations of amino acids in the plasma of neonatal foals with septicemia.

    PubMed

    Zicker, S C; Spensley, M S; Rogers, Q R; Willits, N H

    1991-07-01

    Concentrations of amino acids in the plasma of 13 neonatal foals with septicemia were compared with the concentrations of amino acids in the plasma of 13 age-matched neonatal foals without septicemia. Analysis of the results revealed significantly lower concentrations of arginine, citrulline, isoleucine, proline, threonine, and valine in the plasma of foals with septicemia. The ratio of the plasma concentrations of the branched chain amino acids (isoleucine, leucine, and valine) to the aromatic amino acids (phenylalanine and tyrosine), was also significantly lower in the foals with septicemia. In addition, the concentrations of alanine, glycine, and phenylalanine were significantly higher in the plasma of foals with septicemia. Therefore, neonatal foals with septicemia had significant differences in the concentrations of several amino acids in their plasma, compared with concentrations from healthy foals. These differences were compatible with protein calorie inadequacy and may be related to an alteration in the intake, production, use, or clearance of amino acids from the plasma pool in sepsis.

  3. Electron anions and the glass transition temperature.

    PubMed

    Johnson, Lewis E; Sushko, Peter V; Tomota, Yudai; Hosono, Hideo

    2016-09-06

    Properties of glasses are typically controlled by judicious selection of the glass-forming and glass-modifying constituents. Through an experimental and computational study of the crystalline, molten, and amorphous [Ca12Al14O32](2+) ⋅ (e(-))2, we demonstrate that electron anions in this system behave as glass modifiers that strongly affect solidification dynamics, the glass transition temperature, and spectroscopic properties of the resultant amorphous material. The concentration of such electron anions is a consequential control parameter: It invokes materials evolution pathways and properties not available in conventional glasses, which opens a unique avenue in rational materials design.

  4. Electron anions and the glass transition temperature

    DOE PAGES

    Johnson, Lewis E.; Sushko, Peter V.; Tomota, Yudai; ...

    2016-08-24

    Properties of glasses are typically controlled by judicious selection of the glass-forming and glass-modifying constituents. Through an experimental and computational study of the crystalline, molten, and amorphous [Ca 12Al 14O 32] 2+ ∙ (e –) 2, we demonstrate that electron anions in this system behave as glass-modifiers that strongly affect solidification dynamics, the glass transition temperature, and spectroscopic properties of the resultant amorphous material. Concentration of such electron anions is a consequential control parameter: it invokes materials evolution pathways and properties not available in conventional glasses, which opens a new avenue in rational materials design.

  5. Strategies for improving production performance of probiotic Pediococcus acidilactici viable cell by overcoming lactic acid inhibition.

    PubMed

    Othman, Majdiah; Ariff, Arbakariya B; Wasoh, Helmi; Kapri, Mohd Rizal; Halim, Murni

    2017-11-27

    Lactic acid bacteria are industrially important microorganisms recognized for fermentative ability mostly in their probiotic benefits as well as lactic acid production for various applications. Fermentation conditions such as concentration of initial glucose in the culture, concentration of lactic acid accumulated in the culture, types of pH control strategy, types of aeration mode and different agitation speed had influenced the cultivation performance of batch fermentation of Pediococcus acidilactici. The maximum viable cell concentration obtained in constant fed-batch fermentation at a feeding rate of 0.015 L/h was 6.1 times higher with 1.6 times reduction in lactic acid accumulation compared to batch fermentation. Anion exchange resin, IRA 67 was found to have the highest selectivity towards lactic acid compared to other components studied. Fed-batch fermentation of P. acidilactici coupled with lactic acid removal system using IRA 67 resin showed 55.5 and 9.1 times of improvement in maximum viable cell concentration compared to fermentation without resin for batch and fed-batch mode respectively. The improvement of the P. acidilactici growth in the constant fed-batch fermentation indicated the use of minimal and simple process control equipment is an effective approach for reducing by-product inhibition. Further improvement in the cultivation performance of P. acidilactici in fed-bath fermentation with in situ addition of anion-exchange resin significantly helped to enhance the growth of P. acidilactici by reducing the inhibitory effect of lactic acid and thus increasing probiotic production.

  6. Long term (1987-2012) trends in water chemistry of acid sensitive Swedish lakes

    NASA Astrophysics Data System (ADS)

    Futter, Martyn; Valinia, Salar; Fölster, Jens

    2014-05-01

    Acidification of surface waters is a serious concern in Sweden. During the 1970s and 1980s, many surface waters in Sweden were acidified by long-range pollution. Legislated emissions reductions have led to the recovery of many water bodies but today, there are concerns about the possibility of re-acidification. Sweden is committed to a goal of natural acidification only (i.e. no anthropogenic acidification). Here, we present long term (1987-2012) trends in strong acid anion, base cation, organic carbon and alkalinity measurements. Lakes are defined as acidified in Sweden if pH is more than 0.4 units less than a reference (1860) pH estimated using MAGIC, a widely used process-based model of acidification. Using this criteria, many acid sensitive Swedish lakes are still acidified. A changing climate and more intensive forest harvesting may further delay the recovery from acidification. Average measured alkalinity in the 38 lakes presented here was <= 0.02 mekv/l between 2000-2012. Strong acid anion concentrations declined, primarily as a result of declines in sulfate. Chloride is now the dominant anion in many of these lakes. Base cations concentrations have declined less rapidly, leading to an increase in charge balance ANC. This increase in charge balance ANC has not been matched by an increase in measured alkalinity. Total organic carbon concentrations have increased significantly in many of these lakes, to the point where modeled organic acidity is now approximately equal to inorganic acidity. While the results presented here conform to acidification theory, they illustrate the value of long-term monitoring for assessing the effects of pollutant reduction measures, identifying new threats to water quality and corroborating model results. Most importantly, the long-term monitoring results presented here can be an important tool for informing environmental policy.

  7. Squarylium-based chromogenic anion sensors

    NASA Astrophysics Data System (ADS)

    Lee, Eun-Mi; Gwon, Seon-Yeong; Son, Young-A.; Kim, Sung-Hoon

    2012-09-01

    A squarylium (SQ) dye was synthesized by the reaction between squaric acid and 2,3,3-trimethylindolenine and its anion sensing properties were investigated using absorption and emission spectroscopy. This chemosensor exhibited high selectivity for CN- as compared with F-, CHCO2-, Br-, HPO4-, Cl-, and NO3- in acetonitrile, which was attributed to the formation of a 1:1 squarylium:CN- coordination complex, the formation of which was supported by the calculated geometry of the complex.

  8. Novel fragmentation pathways of anionic adducts of steroids formed by electrospray anion attachment involving regioselective attachment, regiospecific decompositions, charge-induced pathways, and ion-dipole complex intermediates.

    PubMed

    Rannulu, Nalaka S; Cole, Richard B

    2012-09-01

    The analysis of several bifunctional neutral steroids, 5-α-pregnane diol (5-α-pregnane-3α-20βdiol), estradiol (3,17α-dihydroxy-1,3,5(10)-estratriene), progesterone (4-pregnene-3,20-dione), lupeol (3β-hydroxy-20(29)-lupene), pregnenolone (5-pregnen-3β-ol-20-one), and pregnenolone acetate (5-pregnen-3β-ol-20-one acetate) was accomplished by negative ion electrospray mass spectrometry (ESI-MS) employing adduct formation with various anions: fluoride, bicarbonate, acetate, and chloride. Fluoride yielded higher abundances of anionic adducts and more substantial abundances of deprotonated molecules compared with other investigated anions. Collision-induced dissociation (CID) of precursor [M + anion](-) adducts of these steroids revealed that fluoride adduct [M + F](-) precursors first lose HF to produce [M - H](-) and then undergo consecutive decompositions to yield higher abundances of structurally-informative product ions than the other tested anions. In addition to charge-remote fragmentations, the majority of CID pathways of estradiol are deduced to occur via charge-induced fragmentation. Most interestingly, certain anions exhibit preferential attachment to a specific site on these bifunctional steroid molecules, which we are calling "regioselective anion attachment." Regioselective anion attachment is evidenced by subsequent regiospecific decomposition. Regioselective attachment of fluoride (and acetate) anions to low (and moderate) acidity functional groups of pregnenolone, respectively, is demonstrated using deuterated compounds. Moreover, the formation of unique intermediate ion-dipole complexes leading to novel fragmentation pathways of fluoride adducts of pregnenolone acetate, and bicarbonate adducts of d(4)-pregnenolone, are also discussed.

  9. Novel Fragmentation Pathways of Anionic Adducts of Steroids Formed by Electrospray Anion Attachment Involving Regioselective Attachment, Regiospecific Decompositions, Charge-Induced Pathways, and Ion-Dipole Complex Intermediates

    NASA Astrophysics Data System (ADS)

    Rannulu, Nalaka S.; Cole, Richard B.

    2012-09-01

    The analysis of several bifunctional neutral steroids, 5-α-pregnane diol (5-α-pregnane-3α-20βdiol), estradiol (3,17α-dihydroxy-1,3,5(10)-estratriene), progesterone (4-pregnene-3,20-dione), lupeol (3β-hydroxy-20(29)-lupene), pregnenolone (5-pregnen-3β-ol-20-one), and pregnenolone acetate (5-pregnen-3β-ol-20-one acetate) was accomplished by negative ion electrospray mass spectrometry (ESI-MS) employing adduct formation with various anions: fluoride, bicarbonate, acetate, and chloride. Fluoride yielded higher abundances of anionic adducts and more substantial abundances of deprotonated molecules compared with other investigated anions. Collision-induced dissociation (CID) of precursor [M + anion]- adducts of these steroids revealed that fluoride adduct [M + F]- precursors first lose HF to produce [M - H]- and then undergo consecutive decompositions to yield higher abundances of structurally-informative product ions than the other tested anions. In addition to charge-remote fragmentations, the majority of CID pathways of estradiol are deduced to occur via charge-induced fragmentation. Most interestingly, certain anions exhibit preferential attachment to a specific site on these bifunctional steroid molecules, which we are calling "regioselective anion attachment." Regioselective anion attachment is evidenced by subsequent regiospecific decomposition. Regioselective attachment of fluoride (and acetate) anions to low (and moderate) acidity functional groups of pregnenolone, respectively, is demonstrated using deuterated compounds. Moreover, the formation of unique intermediate ion-dipole complexes leading to novel fragmentation pathways of fluoride adducts of pregnenolone acetate, and bicarbonate adducts of d4-pregnenolone, are also discussed.

  10. Thermal decarboxylation of acetic acid: Implications for origin of natural gas

    USGS Publications Warehouse

    Kharaka, Y.K.; Carothers, W.W.; Rosenbauer, R.J.

    1983-01-01

    Laboratory experiments on the thermal decarboxylation of solutions of acetic acid at 200??C and 300??C were carried out in hydrothermal equipment allowing for on-line sampling of both the gas and liquid phases for chemical and stable-carbon-isotope analyses. The solutions had ambient pH values between 2.5 and 7.1; pH values and the concentrations of the various acetate species at the conditions of the experiments were computed using a chemical model. Results show that the concentrations of acetic acid, and not total acetate in solution, control the reaction rates which follow a first order equation based on decreasing concentrations of acetic acid with time. The decarboxylation rates at 200??C (1.81 ?? 10-8 per second) and 300??C (8.17 ?? 10-8 per second) and the extrapolated rates at lower temperatures are relatively high. The activation energy of decarboxylation is only 8.1 kcal/mole. These high decarboxylation rates, together with the distribution of short-chained aliphatic acid anions in formation waters, support the hypothesis that acid anions are precursors for an important portion of natural gas. Results of the ??13C values of CO2, CH4, and total acetate show a reasonably constant fractionation factor of about 20 permil between CO2 and CH4 at 300??C. The ??13C values of CO2 and CH4 are initially low and become higher as decarboxylation increases. ?? 1983.

  11. Methodology of analysis of very weak acids by isotachophoresis with electrospray-ionization mass-spectrometric detection: Anionic electrolyte systems for the medium-alkaline pH range.

    PubMed

    Malá, Zdena; Gebauer, Petr

    2018-01-15

    This work describes for the first time a functional electrolyte system setup for anionic isotachophoresis (ITP) with electrospray-ionization mass-spectrometric (ESI-MS) detection in the neutral to medium-alkaline pH range. So far no application was published on the analysis of very weak acids by anionic ITP-MS although there is a broad spectrum of potential analytes with pK a values in the range 5-10, where application of this technique promises interesting gains in both sensitivity and specificity. The problem so far was the lack of anionic ESI-compatible ITP systems in the mentioned pH range as all typical volatile anionic system components are fully ionized at neutral and alkaline pH and thus too fast to suit as terminators. We propose an original solution of the problem based on the combination of two ITP methods: (i) use of the hydroxyl ion as a natural and ESI-compatible terminator, and (ii) use of configurations based on moving-boundary ITP. The former method ensures effective stacking of analytes by an alkaline terminator of sufficiently low mobility and the latter offers increased flexibility for tuning of the separation window and selectivity according to actual needs. A theoretical description of the proposed model is presented and applied to the design of very simple functional electrolyte configurations. The properties of example systems are demonstrated by both computer simulation and experiments with a group of model analytes. Potential effects of carbon dioxide present in the solutions are demonstrated for particular systems. Experimental results confirm that the proposed methodology is well capable of performing sensitive and selective ITP-MS analyses of very weak acidic analytes (e.g. sulfonamides or chlorophenols). Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Effect of Acid-Base Equilibrium on Absorption Spectra of Humic acid in the Presence of Copper Ions

    NASA Astrophysics Data System (ADS)

    Lavrik, N. L.; Mulloev, N. U.

    2014-03-01

    The reaction between humic acid (HA, sample IHSS) and a metal ion (Cu2+) that was manifested as absorption bands in the range 210-350 nm was recorded using absorption spectroscopy. The reaction was found to be more effective as the pH increased. These data were interpreted in the framework of generally accepted concepts about the influence of acid-base equilibrium on the dissociation of salts, according to which increasing the solution pH increases the concentration of HA anions. It was suggested that [HA-Cu2+] complexes formed.

  13. What is the clinical significance of 5-oxoproline (pyroglutamic acid) in high anion gap metabolic acidosis following paracetamol (acetaminophen) exposure?

    PubMed

    Liss, D B; Paden, M S; Schwarz, E S; Mullins, M E

    2013-11-01

    Paracetamol (acetaminophen) ingestion is the most frequent pharmaceutical overdose in the developed world. Metabolic acidosis sometimes occurs, but the acidosis is infrequently persistent or severe. A growing number of case reports and case series describe high anion gap metabolic acidosis (HAGMA) following paracetamol exposure with subsequent detection or measurement of 5-oxoproline (also called pyroglutamic acid) in blood, urine, or both. Typically 5-oxoprolinuria or 5-oxoprolinemia occurs in the setting of inborn genetic errors in glutathione metabolism. It is unknown whether 5-oxoprolinemia in the setting of paracetamol exposure reflects an acquired or transient derangement of glutathione metabolism or previously unrecognized genetic defects. We reviewed the published cases of 5-oxoprolinemia or 5-oxoprolinuria among patients with HAGMA in the setting of paracetamol exposure. Our goal was to identify any consistent features that might increase our understanding of the pathophysiology, diagnosis, and treatment of similar cases. We searched the medical literature using PUBMED and EMBASE from inception to 28 August 2013 applying search terms ("oxoproline" OR "pyroglutamic acid" AND "paracetamol" OR "acetaminophen"). The intersection of these two searches returned 77 articles, of which 64 involved human subjects and were in English. Two articles, one each in Spanish and Dutch, were reviewed. An additional Google Scholar search was done with the same terms. We manually searched the reference lists of retrieved articles to identify additional four relevant articles. We focused on articles including measured 5-oxoproline concentrations in urine or blood. Twenty-two articles included quantified 5-oxoproline concentrations. Several additional articles mentioned only qualitative detection of 5-oxoproline in urine or blood without concentrations being reported. Our manual reference search yielded four additional articles for a total of 24 articles describing 43 patients

  14. Spectroscopic studies on the antioxidant activity of ellagic acid

    NASA Astrophysics Data System (ADS)

    Kilic, Ismail; Yeşiloğlu, Yeşim; Bayrak, Yüksel

    2014-09-01

    Ellagic acid (EA, C14H6O8) is a natural dietary polyphenol whose benefits in a variety of diseases shown in epidemiological and experimental studies involve anti-inflammation, anti-proliferation, anti-angiogenesis, anticarcinogenesis and anti-oxidation properties. In vitro radical scavenging and antioxidant capacity of EA were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2‧-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe2+) chelating activity and ferric ions (Fe3+) reducing ability. EA inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45 μg/mL concentration. On the other hand, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), α-tocopherol and ascorbic acid displayed 69.8%, 66.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, EA had an effective DPPH• scavenging, ABTSrad + scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe3+) reducing power and ferrous ions (Fe2+) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that EA can be used in the pharmacological, food industry and medicine because of these properties.

  15. Capillary electrophoresis separation of neutral organic compounds, pharmaceutical drugs, proteins and peptides, enantiomers, and anions

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

    Ding, Wei -Liang

    1999-02-12

    Addition of a novel anionic surfactant, namely lauryl polyoxyethylene sulfate, to an aqueous-acetonitrile electrolyte makes it possible to separate nonionic organic compounds by capillary electrophoresis. Separation is based on differences in the association between analytes and the surfactant. Highly hydrophobic compounds such as polyaromatic hydrocarbons are well separated by this new surfactant. Migration times of analytes can be readily changed over an unusually large range by varying the additive concentration and the proportion of acetonitrile in the electrolyte. Several examples are given, including the separation of four methylbenz[a]anthracene isomers and the separation of normal and deuterated acetophenone. The effect ofmore » adding this new surfactant to the acidic electrolyte was also investigated. Incorporation of cetyltrimethylammonium bromide in the electrolyte is shown to dynamically coat the capillary and reverse electroosmotic flow. Chiral recognition mechanism is studied using novel synthetic surfactants as chiral selectors, which are made from amino acids reacting with alkyl chloroformates. A satisfactory separation of both inorganic and organic anions is obtained using electrolyte solutions as high as 5 M sodium chloride using direct photometric detection. The effect of various salts on electrophoretic and electroosmotic mobility is further discussed. Several examples are given under high-salt conditions.« less

  16. Pentacoordinate silicon(IV): cationic, anionic and neutral complexes derived from the reaction of NHC→SiCl4 with highly Lewis acidic (C2F5)2SiH2.

    PubMed

    Böttcher, T; Steinhauer, S; Neumann, B; Stammler, H-G; Röschenthaler, G-V; Hoge, B

    2014-06-14

    Addition of NHC→SiCl4 to the highly Lewis acidic bis(pentafluoroethyl)silane ((C2F5)2SiH2) afforded the salt [(NHC)2SiCl2H][(C2F5)2SiCl3] with pentacoordinate silicon in the cation and the anion. The anion represents the first example of a chlorosilicate structurally characterized in the solid state. In this reaction, the long sought pentacoordinate NHC-adduct of silicochloroform was identified as an intermediate and its crystal structure is presented.

  17. Comparative semiempirical and ab initio study of the structural and chemical properties of uric acid and its anions

    NASA Astrophysics Data System (ADS)

    Altarsha, Muhannad; Monard, Gérald; Castro, Bertrand

    Semiempirical, density functional theory (DFT), and ab initio calculations have been performed to assess the relative stabilities of 15 possible tautomer forms of neutral uric acid, and of the different urate mono- and dianion forms. These methods have also been used to compute ionization potentials (IPs) for uric acid and its derived anions. Overall, we have found that semiempirical calculations, in particular PM3, perform well as compared with B3LYP or MP2 computations toward these different structural and chemical properties of uric acid: the triketo form of uric acid is the most stable tautomer form of neutral uric acid. Three other tautomer forms are relatively close in energy, within the range 2-6 kcal/mol above the triketo form, with a mean energy deviation of only 1.3 kcal/mol between PM3 and DFT or ab initio results; the monoanion form of uric acid obtained by abstracting one proton in position 3 (denoted UAN3-) is the most stable form among all four possible urate monoanions both in gas phase and in solution; the dianion form of uric acid obtained by abstracting two protons, respectively, in positions 3 and 9 of uric acid (denoted UAN3-N9-) is the most stable urate dianion form both in gas phase and in solution. However, these two most stable species do not have the lowest IPs in solution: among monoanions and dianions, respectively, the species with the lowest IPs are UAN7- and UAN7-N9-.

  18. Diclofenac removal in urine using strong-base anion exchange polymer resins.

    PubMed

    Landry, Kelly A; Boyer, Treavor H

    2013-11-01

    One of the major sources of pharmaceuticals in the environment is wastewater effluent of which human urine contributes the majority of pharmaceuticals. Urine source separation has the potential to isolate pharmaceuticals at a higher concentration for efficient removal as well as produce a nutrient byproduct. This research investigated the efficacy of using strong-base anion exchange polymer resins to remove the widely detected and abundant pharmaceutical, diclofenac, from synthetic human urine under fresh and ureolyzed conditions. The majority of experiments were conducted using a strong-base, macroporous, polystyrene resin (Purolite A520E). Ion-exchange followed a two-step removal rate with rapid removal in 1 h and equilibrium removal in 24 h. Diclofenac removal was >90% at a resin dose of 8 mL/L in both fresh and ureolyzed urine. Sorption of diclofenac onto A520E resin was concurrent with desorption of an equivalent amount of chloride, which indicates the ion-exchange mechanism is occurring. The presence of competing ions such as phosphate and citrate did not significantly impact diclofenac removal. Comparisons of three polystyrene resins (A520E, Dowex 22, Dowex Marathon 11) as well as one polyacrylic resin (IRA958) were conducted to determine the major interactions between anion exchange resin and diclofenac. The results showed that polystyrene resins provide the highest level of diclofenac removal due to electrostatic interactions between quaternary ammonium functional groups of resin and carboxylic acid of diclofenac and non-electrostatic interactions between resin matrix and benzene rings of diclofenac. Diclofenac was effectively desorbed from A520E resin using a regeneration solution that contained 4.5% (m/m) NaCl in an equal-volume mixture of methanol and water. The greater regeneration efficiency of the NaCl/methanol-water mixture over the aqueous NaCl solution supports the importance of non-electrostatic interactions between resin matrix and benzene rings

  19. Anion exchange membranes for electrochemical oxidation-reduction energy storage system

    NASA Technical Reports Server (NTRS)

    Odonnell, P. M.; Sheibley, D. W.; Gahn, R. F.

    1977-01-01

    Oxidation-reduction couples in concentrated solutions separated by appropriate ion selective membranes were considered as an attractive approach to bulk electrical energy storage. A key problem is the development of the membrane. Several promising types of anionic membranes are discussed which were developed and evaluated for redox energy storage systems. The copolymers of ethyleneglycoldimethacrylate with either 2-vinylpyridine or vinylbenzl chloride gave stable resistance values compared to the copolymer of vinylbenzlchloride and divinylbenzene which served as the baseline membrane. A polyvinylchloride film aminated with tetraethylenepentamine had a low resistance but a high ion transfer rate. A slurry coated vinylpyridine had the lowest ion transfer rate. All these membranes functioned well in laboratory cells at ambient temperatures with the acidic chloride oxidant/reductant system, Fe 3, Fe 2/Ti 3, Ti 4.

  20. Intercalation of anionic organic ultraviolet ray absorbers into layered zinc hydroxide nitrate.

    PubMed

    Cursino, Ana Cristina Trindade; Gardolinski, José Eduardo Ferreira da Costa; Wypych, Fernando

    2010-07-01

    Layered zinc hydroxide nitrate (ZHN) was synthesized and nitrate ions were topotactically exchanged with three different anionic species of commercial organic ultraviolet (UV) ray absorbers: 2-mercaptobenzoic acid, 2-aminobenzoic acid, and 4-aminobenzoic acid. The exchange reactions were confirmed by X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR), ultraviolet visible (UV-Vis) spectroscopy, and thermal analysis (thermogravimetry, TGA, and differential thermal analysis, DTA). In all the anionic exchanged products, evidence of grafting of the organic species onto the inorganic matrix was obtained. In general, after intercalation/grafting, the UV absorption ability was improved in relation to the use of the parent organic material, showing that layered hydroxide salts (LHS) can be good alternative matrixes for the immobilization of organic species with UV-blocking properties in cosmetic products. Copyright 2010 Elsevier Inc. All rights reserved.

  1. Glomerular anionic site distribution in nonproteinuric rats. A computer-assisted morphometric analysis.

    PubMed

    Pilia, P A; Swain, R P; Williams, A V; Loadholt, C B; Ainsworth, S K

    1985-12-01

    The cationic ultrastructural tracer polyethyleneimine (PEI: pI approximately equal to 11.0), binds electrophysically to uniformly spaced discrete electron-dense anionic sites present in the laminae rarae of the rat glomerular basement membrane (GBM), mesangial reflections of the GBM, Bowman's capsule, and tubular basement membranes when administered intravenously. Computer-assisted morphometric analysis of glomerular anionic sites reveals that the maximum concentration of stainable lamina rara externa (lre) sites (21/10,000 A GBM) occurs 60 minutes after PEI injection with a site-site interspacing of 460 A. Lamina rara interna (lri) sites similarly demonstrate a maximum concentration (20/10,000 A GBM) at 60 minutes with a periodicity of 497 A. The concentration and distribution of anionic sites within the lri was irregular in pattern and markedly decreased in number, while the lre possesses an electrical field that is highly regular at all time intervals analyzed (15, 30, 60, 120, 180, 240, and 300 minutes). Immersion and perfusion of renal tissue with PEI reveals additional heavy staining of the epithelial and endothelial cell sialoprotein coatings. PEI appears to bind to glomerular anionic sites reversibly: ie, between 60 and 180 minutes the concentration of stained sites decreases. At 300 minutes, the interspacing once again approaches the 60-minute concentration. This suggests a dynamic turnover or dissociation followed by a reassociation of glomerular negatively charged PEI binding sites. In contrast, morphometric analysis of anionic sites stained with lysozyme and protamine sulfate reveals interspacings of 642 A and 585 A, respectively; in addition, these tracers produce major glomerular ultrastructural alterations and induce transient proteinuria. PEI does not induce proteinuria in rats, nor does it produce glomerular morphologic alterations when ten times the tracer dosage is administered intravenously. These findings indicate that the choice of

  2. Removal of anionic dye Congo red from aqueous solution by raw pine and acid-treated pine cone powder as adsorbent: equilibrium, thermodynamic, kinetics, mechanism and process design.

    PubMed

    Dawood, Sara; Sen, Tushar Kanti

    2012-04-15

    Pine cone a natural, low-cost agricultural by-product in Australia has been studied for its potential application as an adsorbent in its raw and hydrochloric acid modified form. Surface study of pine cone and treated pine cone was investigated using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The modification process leads to increases in the specific surface area and decreases mean particle sizes of acid-treated pine cone when compared to raw pine cone biomass. Batch adsorption experiments were performed to remove anionic dye Congo red from aqueous solution. It was found that the extent of Congo red adsorption by both raw pine cone biomass and acid-treated biomass increased with initial dye concentration, contact time, temperature but decreased with increasing solution pH and amount of adsorbent of the system. Overall, kinetic studies showed that the dye adsorption process followed pseudo-second-order kinetics based on pseudo-first-order and intra-particle diffusion models. The different kinetic parameters including rate constant, half-adsorption time, and diffusion coefficient were determined at different physico-chemical conditions. Equilibrium data were best represented by Freundlich isotherm model among Langmuir and Freundlich adsorption isotherm models. It was observed that the adsorption was pH dependent and the maximum adsorption of 32.65 mg/g occurred at pH of 3.55 for an initial dye concentration of 20 ppm by raw pine cone, whereas for acid-treated pine cone the maximum adsorption of 40.19 mg/g for the same experimental conditions. Freundlich constant 'n' also indicated favourable adsorption. Thermodynamic parameters such as ∆G(0), ∆H(0), and ∆S(0) were calculated. A single-stage batch absorber design for the Congo red adsorption onto pine cone biomass also presented based on the Freundlich isotherm model equation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Acid-base equilibrium in aqueous solutions of 1,3-dimethylbarbituric acid as studied by 13C NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Gryff-Keller, A.; Kraska-Dziadecka, A.

    2011-12-01

    13C NMR spectra of 1,3-dimethylbarbituric acid in aqueous solutions of various acidities and for various solute concentrations have been recorded and interpreted. The spectra recorded at pH = 2 and below contain the signals of the neutral solute molecule exclusively, while the ones recorded at pH = 7 and above only the signals of the appropriate anion, which has been confirmed by theoretical GIAO-DFT calculations. The signals in the spectra recorded for solutions of pH < 7 show dynamic broadenings. The lineshape analysis of these signals has provided information on the kinetics of the processes running in the dynamic acid-base equilibrium. The kinetic data determined this way have been used to clarify the mechanisms of these processes. The numerical analysis has shown that under the investigated conditions deprotonation of the neutral solute molecules undergoes not only via a simple transfer of the C-H proton to water molecules but also through a process with participation of the barbiturate anions. Moreover, the importance of tautomerism, or association, or both these phenomena for the kinetics of the acid-base transformations in the investigated system has been shown. Qualitatively similar changes of 13C NMR spectra with the solution pH variation have been observed for the parent barbituric acid.

  4. Molecular structure investigation of neutral, dimer and anion forms of 3,4-pyridinedicarboxylic acid: A combined experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Karabacak, Mehmet; Bilgili, Sibel; Atac, Ahmet

    2015-01-01

    In this study, the structural and vibrational analysis of 3,4-pyridinedicarboxylic acid (3,4-PDCA) are presented using experimental techniques as FT-IR, FT-Raman, NMR, UV and quantum chemical calculations. FT-IR and FT-Raman spectra of 3,4-pyridinedicarboxylic acid in the solid phase are recorded in the region 4000-400 cm-1 and 4000-50 cm-1, respectively. The geometrical parameters and energies of all different and possible monomer, dimer, anion-1 and anion-2 conformers of 3,4-PDCA are obtained from Density Functional Theory (DFT) with B3LYP/6-311++G(d,p) basis set. There are sixteen conformers (C1sbnd C16) for this molecule (neutral form). The most stable conformer of 3,4-PDCA is the C1 conformer. The complete assignments are performed on the basis of the total energy distribution (TED) of the vibrational modes calculated with scaled quantum mechanics (SQM) method. 1H and 13C NMR spectra are recorded and the chemical shifts are calculated by using DFT/B3LYP methods with 6-311++G(d,p) basis set. The UV absorption spectrum of the studied compound is recorded in the range of 200-400 nm by dissolved in ethanol. The optimized geometric parameters were compared with experimental data via the X-ray results derived from complexes of this molecule. In addition these, molecular electrostatic potential (MEP), thermodynamic and electronic properties, HOMO-LUMO energies and Mulliken atomic charges, are performed.

  5. Oxidation of Gas-Phase SO2 on the Surfaces of Acidic Microdroplets: Implications for Sulfate and Sulfate Radical Anion Formation in the Atmospheric Liquid Phase.

    PubMed

    Hung, Hui-Ming; Hoffmann, Michael R

    2015-12-01

    The oxidation of SO2(g) on the interfacial layers of microdroplet surfaces was investigated using a spray-chamber reactor coupled to an electrospray ionization mass spectrometer. Four major ions, HSO3(-), SO3(•-), SO4(•-) and HSO4(-), were observed as the SO2(g)/N2(g) gas-mixture was passed through a suspended microdroplet flow, where the residence time in the dynamic reaction zone was limited to a few hundred microseconds. The relatively high signal intensities of SO3(•-), SO4(•-), and HSO4(-) compared to those of HSO3(-) as observed at pH < 3 without addition of oxidants other than oxygen suggests an efficient oxidation pathway via sulfite and sulfate radical anions on droplets possibly via the direct interfacial electron transfer from HSO3(-) to O2. The concentrations of HSO3(-) in the aqueous aerosol as a function of pH were controlled by the deprotonation of hydrated sulfur dioxide, SO2·H2O, which is also affected by the pH dependent uptake coefficient. When H2O2(g) was introduced into the spray chamber simultaneously with SO2(g), HSO3(-) is rapidly oxidized to form bisulfate in the pH range of 3 to 5. Conversion to sulfate was less at pH < 3 due to relatively low HSO3(-) concentration caused by the fast interfacial reactions. The rapid oxidation of SO2(g) on the acidic microdroplets was estimated as 1.5 × 10(6) [S(IV)] (M s(-1)) at pH ≤ 3. In the presence of acidic aerosols, this oxidation rate is approximately 2 orders of magnitude higher than the rate of oxidation with H2O2(g) at a typical atmospheric H2O2(g) concentration of 1 ppb. This finding highlights the relative importance of the acidic surfaces for SO2 oxidation in the atmosphere. Surface chemical reactions on aquated aerosol surfaces, as observed in this study, are overlooked in most atmospheric chemistry models. These reaction pathways may contribute to the rapid production of sulfate aerosols that is often observed in regions impacted by acidic haze aerosol such as Beijing and other

  6. The influence of total organic carbon (TOC) on the relationship between acid neutralizing capacity (ANC) and fish status in Norwegian lakes.

    PubMed

    Lydersen, Espen; Larssen, Thorjørn; Fjeld, Eirik

    2004-06-29

    Acid neutralizing capacity (ANC) is the parameter most commonly used as chemical indicator for fish response to acidification. Empirical relationships between fish status of surface waters and ANC have been documented earlier. ANC is commonly calculated as the difference between base cations ([BC]=[Ca2+]+[Mg2+]+[N+]+[K+]) and strong acid anions ([SAA]=[SO4(2)-]+[NO3-]+[Cl-]). This is a very robust calculation of ANC, because none of the parameters incorporated are affected by the partial pressure of CO2, in contrast to the remaining major ions in waters, pH ([H+]), aluminum ([Aln+]), alkalinity ([HCO3-/CO3(2)-]) and organic anions ([An-]). Here we propose a modified ANC calculation where the permanent anionic charge of the organic acids is assumed as a part of the strong acid anions. In many humic lakes, the weak organic acids are the predominant pH-buffering system. Because a significant amount of the weak organic acids have pK-values<3.0-3.5, these relatively strong acids will permanently be deprotonated in almost all natural waters (i.e. pH>4.5). This means that they will be permanently present as anions, equal to the strong acid inorganic anions, SO4(2)-, NO3- and Cl-. In the literature, natural organic acids are often described as triprotic acids with a low pK1 value. Assuming a triprotic model, we suggest to add 1/3 of the organic acid charge density to the strong acid anions in the ANC calculation. The suggested organic acid adjusted ANC (ANC(OAA)), is then calculated as follows: ANC(OAA)=[BC]-([SAA]+1/3CD*TOC) where TOC is total organic carbon (mg C L(-1)), and CD=10.2 is charge density of the organic matter (microeq/mg C), based on literature data from Swedish lakes. ANC(OAA) gives significant lower values of ANC in order to achieve equal fish status compared with the traditional ANC calculation. Using ANC(OAA) the humic conditions in lakes are better taken into account. This may also help explain observations of higher ANC needed to have reproducing fish

  7. Contact ion pair formation between hard acids and soft bases in aqueous solutions observed with 2DIR spectroscopy.

    PubMed

    Sun, Zheng; Zhang, Wenkai; Ji, Minbiao; Hartsock, Robert; Gaffney, Kelly J

    2013-12-12

    The interaction of charged species in aqueous solution has important implications for chemical, biological, and environmental processes. We have used 2DIR spectroscopy to study the equilibrium dynamics of thiocyanate chemical exchange between free ion (NCS(-)) and contact ion pair configurations (MNCS(+)), where M(2+) = Mg(2+) or Ca(2+). Detailed studies of the influence of anion concentration and anion speciation show that the chemical exchange observed with the 2DIR measurements results from NCS(-) exchanging with other anion species in the first solvation shell surrounding Mg(2+) or Ca(2+). The presence of chemical exchange in the 2DIR spectra provides an indirect, but robust, determinant of contact ion pair formation. We observe preferential contact ion pair formation between soft Lewis base anions and hard Lewis acid cations. This observation cannot be easily reconciled with Pearson's acid-base concept or Collins' Law of Matching Water Affinities. The anions that form contact ion pairs also correspond to the ions with an affinity for water and protein surfaces, so similar physical and chemical properties may control these distinct phenomena.

  8. Strong ion calculator--a practical bedside application of modern quantitative acid-base physiology.

    PubMed

    Lloyd, P

    2004-12-01

    To review acid-base balance by considering the physical effects of ions in solution and describe the use of a calculator to derive the strong ion difference and Atot and strong ion gap. A review of articles reporting on the use of strong ion difference and Atot in the interpretation of acid base balance. Tremendous progress has been made in the last decade in our understanding of acid-base physiology. We now have a quantitative understanding of the mechanisms underlying the acidity of an aqueous solution. We can now predict the acidity given information about the concentration of the various ion-forming species within it. We can predict changes in acid-base status caused by disturbance of these factors, and finally, we can detect unmeasured anions with greater sensitivity than was previously possible with the anion gap, using either arterial or venous blood sampling. Acid-base interpretation has ceased to be an intuitive and arcane art. Much of it is now an exact computation that can be automated and incorporated into an online hospital laboratory information system. All diseases and all therapies can affect a patient's acid-base status only through the final common pathway of one or more of the three independent factors. With Constable's equations we can now accurately predict the acidity of plasma. When there is a discrepancy between the observed and predicted acidity we can deduce the net concentration of unmeasured ions to account for the difference.

  9. Secular trend of serum docosahexaenoic acid, eicosapentaenoic acid, and arachidonic acid concentrations among Japanese-a 4- and 13-year descriptive epidemiologic study.

    PubMed

    Otsuka, Rei; Kato, Yuki; Imai, Tomoko; Ando, Fujiko; Shimokata, Hiroshi

    2015-03-01

    Cross-sectional studies have shown age-related increases in blood docosahexaenoic and eicosapentaenoic acid and decreases in arachidonic acid. We describe serum docosahexaenoic, eicosapentaenoic, and arachidonic acid concentrations over 13 years (1997-2012) across four study waves and serum fatty acid composition over 4 years (2006-2012) between two study waves according to age groups by sex in the same subjects. We included 443 men and 435 women aged 40-79 years at baseline. Serum arachidonic acid concentrations increased in all sex and age groups over 13 years, and eicosapentaenoic or docosahexaenoic acid concentrations increased in males and females who were younger and middle-aged at baseline. Only serum arachidonic acid composition increased over 4 years in men and women who were 40-69 years at baseline, even after adjustment for arachidonic acid intake. These findings suggest a secular increase trend in serum arachidonic acid levels over 13 years among randomly selected community-dwelling middle-aged and elderly Japanese. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Influence of humic acid on the removal of arsenate and arsenic by ferric chloride: effects of pH, As/Fe ratio, initial As concentration, and co-existing solutes.

    PubMed

    Kong, Yanli; Kang, Jing; Shen, Jimin; Chen, Zhonglin; Fan, Leitao

    2017-01-01

    The influence of humic acid (HA) on the removal of arsenic by FeCl 3 was systematically studied in this paper. Jar tests were performed to investigate the influence on arsenic during FeCl 3 coagulation of the pH adjusting method, the initial As/Fe ratio, the equilibrium As concentration, and co-occurring anions and cations. Compared with results in HA-free systems, the removal trends of arsenic in HA solutions were quite different. It was found that As(V) removal was higher at low equilibrium concentration, yet the opposite was true for As(III) removal. The presence of HA influenced the effective number of active sites for arsenic removal by FeCl 3 flocculation. In addition, in the presence of HA, the impacts of co-existing solutions on arsenic removal were also different from that of an HA-free system. This study examined the influence of co-occurring anions, such as phosphate, sulfate, and silicate on arsenic removal, depending on their ability to compete for sorption sites and to hinder or facilitate the aggregation of ferric hydroxide flocs. The presence of Ca 2+ or Cd 2+ significantly increased arsenic removal at higher pH. Low concentrations of dissolved HA and high concentrations of colloid affected the adsorption of arsenic onto iron oxide. The influence of HA on the adsorption of arsenic onto iron oxide primarily depended on the relative content of the dissolved and mineral combination states of HA and the interface combination forms.

  11. Pu Anion Exchange Process Intensification

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

    Taylor-Pashow, Kathryn M. L.

    This research is focused on improving the efficiency of the anion exchange process for purifying plutonium. While initially focused on plutonium, the technology could also be applied to other ion-exchange processes. Work in FY17 focused on the improvement and optimization of porous foam columns that were initially developed in FY16. These foam columns were surface functionalized with poly(4-vinylpyridine) (PVP) to provide the Pu specific anion-exchange sites. Two different polymerization methods were explored for maximizing the surface functionalization with the PVP. The open-celled polymeric foams have large open pores and large surface areas available for sorption. The fluid passes through themore » large open pores of this material, allowing convection to be the dominant mechanism by which mass transport takes place. These materials generally have very low densities, open-celled structures with high cell interconnectivity, small cell sizes, uniform cell size distributions, and high structural integrity. These porous foam columns provide advantages over the typical porous resin beads by eliminating the slow diffusion through resin beads, making the anion-exchange sites easily accessible on the foam surfaces. The best performing samples exceeded the Pu capacity of the commercially available resin, and also offered the advantage of sharper elution profiles, resulting in a more concentrated product, with less loss of material to the dilute heads and tails cuts. An alternate approach to improving the efficiency of this process was also explored through the development of a microchannel array system for performing the anion exchange.« less

  12. The effect of interlayer anion on the reactivity of Mg-Al layered double hydroxides: improving and extending the customization capacity of anionic clays.

    PubMed

    Rojas, Ricardo; Bruna, Felipe; de Pauli, Carlos P; Ulibarri, M Ángeles; Giacomelli, Carla E

    2011-07-01

    Layered double hydroxides (LDHs) reactivity and interfacial behavior are closely interconnected and control particle properties relevant to the wide range of these solids' applications. Despite their importance, their relationship has been hardly described. In this work, chloride and dodecylsulfate (DDS(-)) intercalated LDHs are studied combining experimental data (electrophoretic mobility and contact angle measurements, hydroxyl and organic compounds uptake) and a simple mathematical model that includes anion-binding and acid-base reactions. This approach evidences the anion effect on LDHs interfacial behavior, reflected in the opposite particle charge and the different surface hydrophobic/hydrophilic character. LDHs reactivity are also determined by the interlayer composition, as demonstrated by the cation uptake capability of the DDS(-) intercalated sample. Consequently, the interlayer anion modifies the LDHs interfacial properties and reactivity, which in turn extends the customization capacity of these solids. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. Surface charge fine tuning of reversed-phase/weak anion-exchange type mixed-mode stationary phases for milder elution conditions.

    PubMed

    Zimmermann, Aleksandra; Horak, Jeannie; Sánchez-Muñoz, Orlando L; Lämmerhofer, Michael

    2015-08-28

    A series of new mixed-mode reversed-phase/weak anion-exchange (RP/WAX) phases have been synthesized by immobilization of N-undecenyl-3-α-aminotropane onto thiol-modified silica gel by thiol-ene click chemistry and subsequent introduction of acidic thiol-endcapping functionalities of different type and surface densities. Click chemistry allowed to adjust a controlled surface concentration of the RP/WAX ligand in such a way that a sufficient quantity of residual thiols remained unmodified which have been capped by thiol click with either 3-butenoic acid or allylsulfonic acid as co-ligands. In another embodiment, performic acid oxidation of N-undecenyl-3-α-aminotropane-derivatized thiol-modified silica gave a RP/WAX phase with high density of sulfonic acid end-capping groups. ζ-Potential determinations confirmed the fine-tuned pI of these mixed-mode stationary phases which was shifted from 9.5 to 8.2, 7.8, and 6.5 with 3-butenoic acid and allylsulfonic acid end-capping as well as performic acid oxidation. For acidic solutes, the co-ionic endcapping leads to strongly reduced retention times and clearly allowed elution of these analytes under lower ionic strength thus milder elution conditions. In spite of the acidic endcapping, the new mixed-mode phases maintained their hydrophobic and anion-exchange selectivity as well as their multimodal nature featuring RP and HILIC elution domains at acetonitrile percentages below and above 50%, respectively. Column classification by principal component analysis of an extended retention map in comparison to a set of polar commercial and in-house synthesized stationary phases confirmed complementarity of the new mixed-mode phases with respect to HILIC, polar RP, amino and commercial mixed-mode phases. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Potential for food-drug interactions by dietary phenolic acids on human organic anion transporters 1 (SLC22A6), 3 (SLC22A8), and 4 (SLC22A11).

    PubMed

    Wang, Li; Sweet, Douglas H

    2012-10-15

    Phenolic acids exert beneficial health effects such as anti-oxidant, anti-carcinogenic, and anti-inflammatory activities and show systemic exposure after consumption of common fruits, vegetables, and beverages. However, knowledge regarding which components convey therapeutic benefits and the mechanism(s) by which they cross cell membranes is extremely limited. Therefore, we determined the inhibitory effects of nine food-derived phenolic acids, p-coumaric acid, ferulic acid, gallic acid, gentisic acid, 4-hydroxybenzoic acid, protocatechuic acid, sinapinic acid, syringic acid, and vanillic acid, on human organic anion transporter 1 (hOAT1), hOAT3, and hOAT4. In the present study, inhibition of OAT-mediated transport of prototypical substrates (1 μM) by phenolic acids (100 μM) was examined in stably expressing cell lines. All compounds significantly inhibited hOAT3 transport, while just ferulic, gallic, protocatechuic, sinapinic, and vanillic acid significantly blocked hOAT1 activity. Only sinapinic acid inhibited hOAT4 (~35%). For compounds exhibiting inhibition > ~60%, known clinical plasma concentration levels and plasma protein binding in humans were examined to select compounds to evaluate further with dose-response curves (IC(50) values) and drug-drug interaction (DDI) index determinations. IC(50) values ranged from 1.24 to 18.08 μM for hOAT1 and from 7.35 to 87.36 μM for hOAT3. Maximum DDI indices for gallic and gentisic acid (≫0.1) indicated a very strong potential for DDIs on hOAT1 and/or hOAT3. This study indicates that gallic acid from foods or supplements, or gentisic acid from salicylate-based drug metabolism, may significantly alter the pharmacokinetics (efficacy and toxicity) of concomitant therapeutics that are hOAT1 and/or hOAT3 substrates. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Extracellular determinants of anion discrimination of the Cl-/H+ antiporter protein CLC-5.

    PubMed

    De Stefano, Silvia; Pusch, Michael; Zifarelli, Giovanni

    2011-12-23

    Mammalian CLC proteins comprise both Cl- channels and Cl-/H+ antiporters that carry out fundamental physiological tasks by transporting Cl- across plasma membrane and intracellular compartments. The NO3- over Cl- preference of a plant CLC transporter has been pinpointed to a conserved serine residue located at Scen and it is generally assumed that the other two binding sites of CLCs, Sext and Sin, do not substantially contribute to anion selectivity. Here we show for the Cl-/H+ antiporter CLC-5 that the conserved and extracellularly exposed Lys210 residue is critical to determine the anion specificity for transport activity. In particular, mutations that neutralize or invert the charge at this position reverse the NO3- over Cl- preference of WT CLC-5 at a concentration of 100 mm, but do not modify the coupling stoichiometry with H+. The importance of the electrical charge is shown by chemical modification of K210C with positively charged cysteine-reactive compounds that reintroduce the WT preference for Cl-. At saturating extracellular anion concentrations, neutralization of Lys210 is of little impact on the anion preference, suggesting an important role of Lys210 on the association rate of extracellular anions to Sext.

  16. High serum uric acid concentration predicts poor survival in patients with breast cancer.

    PubMed

    Yue, Cai-Feng; Feng, Pin-Ning; Yao, Zhen-Rong; Yu, Xue-Gao; Lin, Wen-Bin; Qian, Yuan-Min; Guo, Yun-Miao; Li, Lai-Sheng; Liu, Min

    2017-10-01

    Uric acid is a product of purine metabolism. Recently, uric acid has gained much attraction in cancer. In this study, we aim to investigate the clinicopathological and prognostic significance of serum uric acid concentration in breast cancer patients. A total of 443 female patients with histopathologically diagnosed breast cancer were included. After a mean follow-up time of 56months, survival was analysed using the Kaplan-Meier method. To further evaluate the prognostic significance of uric acid concentrations, univariate and multivariate Cox regression analyses were applied. Of the clinicopathological parameters, uric acid concentration was associated with age, body mass index, ER status and PR status. Univariate analysis identified that patients with increased uric acid concentration had a significantly inferior overall survival (HR 2.13, 95% CI 1.15-3.94, p=0.016). In multivariate analysis, we found that high uric acid concentration is an independent prognostic factor predicting death, but insufficient to predict local relapse or distant metastasis. Kaplan-Meier analysis indicated that high uric acid concentration is related to the poor overall survival (p=0.013). High uric acid concentration predicts poor survival in patients with breast cancer, and might serve as a potential marker for appropriate management of breast cancer patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Ultraslow Phase Transitions in an Anion-Anion Hydrogen-Bonded Ionic Liquid.

    PubMed

    Faria, Luiz F O; Lima, Thamires A; Ferreira, Fabio F; Ribeiro, Mauro C C

    2018-02-15

    A Raman spectroscopy study of 1-ethyl-3-methylimidazolium hydrogen sulfate, [C 2 C 1 im][HSO 4 ], as a function of temperature, has been performed to reveal the role played by anion-anion hydrogen bond on the phase transitions of this ionic liquid. Anion-anion hydrogen bonding implies high viscosity, good glass-forming ability, and also moderate fragility of [C 2 C 1 im][HSO 4 ] in comparison with other ionic liquids. Heating [C 2 C 1 im][HSO 4 ] from the glassy phase results in cold crystallization at ∼245 K. A solid-solid transition (crystal I → crystal II) is barely discernible in calorimetric measurements at typical heating rates, but it is clearly revealed by Raman spectroscopy and X-ray diffraction. Raman spectroscopy indicates that crystal I has extended ([HSO 4 ] - ) n chains of hydrogen-bonded anions but crystal II has not. Raman spectra recorded at isothermal condition show the ultraslow dynamics of cold crystallization, solid-solid transition, and continuous melting of [C 2 C 1 im][HSO 4 ]. A brief comparison is also provided between [C 2 C 1 im][HSO 4 ] and [C 4 C 1 im][HSO 4 ], as Raman spectroscopy shows that the latter does not form the crystalline phase with extended anion-anion chains.

  18. Anionic surfactant enhanced phosphate desorption from Mg/Al-layered double hydroxides by micelle formation.

    PubMed

    Shimamura, Akihiro; Jones, Mark I; Metson, James B

    2013-12-01

    Desorption of interlayer hydrogen phosphate (HPO4) from hydrogen phosphate intercalated Mg/Al-layered double hydroxide (LDH-HPO4) by anion exchange with surfactant anions has been investigated under controlled conditions. Three types of surfactant, Dodecylbenzenesulphonate (DBS), Dodecylsulphate (DS) and 1-Octanesulphonate (OS), anions were used for intercalation experiments over a range of concentrations, and for all solutions, it was shown that the desorption of hydrogen phosphate is enhanced at concentrations close to the critical micelle concentration (CMC). Intercalation of the surfactant anions into LDH-HPO4 was confirmed by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning electron microscopy (SEM). More than 90% removal of the hydrogen phosphate was achieved at CMC. Repeat adsorption tests to investigate recyclability showed that desorption with 0.005 M DBS improved subsequent phosphate re-adsorption, allowing around 90% of the original adsorption over three cycles. This is much higher than when desorption was conducted using either Na2CO3 or NaCl-NaOH solutions, even at much higher concentrations. This study suggests potential economic and environmental advantages in using these surfactants in improving the cycling performance of LDH materials as absorbents for clean-up of water systems. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Diagnostic cyclisation reactions which follow phosphate transfer to carboxylate anion centres for energised [M-H]- anions of pTyr-containing peptides.

    PubMed

    Tran, T T Nha; Wang, Tianfang; Hack, Sandra; Bowie, John H

    2011-09-15

    The low-energy negative ion phosphoTyr to C-terminal -CO(2)PO(3)H(2) rearrangement occurs for energised peptide [M-H](-) anions even when there are seven amino acid residues between the pTyr and C-terminal amino acid residues. The rearranged C-terminal -CO(2)PO(2)H(O(-)) group effects characteristic S(N)i cyclisation/cleavage reactions. The most pronounced of these involves the electrophilic central backbone carbon of the penultimate amino acid residue. This reaction is aided by the intermediacy of an H-bonded intermediate in which the nucleophilic and electrophilic reaction centres are held in proximity in order for the S(N)i cyclisation/cleavage to proceed. The ΔG(reaction) is +184 kJ mol(-1) with the barrier to the S(N)i transition state being +240 kJ mol(-1) at the HF/6-31 + G(d)//AM1 level of theory. A similar phosphate rearrangement from pTyr to side chain CO(2)(-) (of Asp or Glu) may also occur for energised peptide [M-H](-) anions. The reaction is favourable: ΔG(reaction) is -44 kJ mol(-1) with a maximum barrier of +21 kJ mol(-1) (to the initial transition state) when Asp and Tyr are adjacent. The rearranged species R(1)-Tyr-NHCH(CH(2)CO(2)PO(3)H(-))COR(2) (R(1)  = CHO; R(2)  = OCH(3)) may undergo an S(N)i six-centred cyclisation/cleavage reaction to form the product anion R(1)-Tyr(NH(-)). This process has a high energy requirement [ΔG(reaction)  = +224 kJ mol(-1), with the barrier to the S(N)i transition state being +299 kJ mol(-1)]. Copyright © 2011 John Wiley & Sons, Ltd.

  20. Effect of different concentrations of sodium dodecyl sulfate and additional anionic surfactant on properties of low protein natural rubber latex

    NASA Astrophysics Data System (ADS)

    Abdullah, Nurulhuda; Manaf, Siti Nor Qamarina; Hassan, Aziana Abu

    2017-12-01

    This paper describes the chemical deproteinization process of natural rubber latex (NRL) using chemical denaturants namely urea and sodium dodecyl sulfate (SDS). Commercial high ammoniated natural rubber latex (HANRL) was incubated with both denaturants - urea and SDS for selected period of time before centrifugation and characterization. The role of SDS in NRL deproteinization process was further elucidated by manipulating the concentration of SDS at 0.3 phr and 0.5 phr during the incubation process. It was found that the physical properties of NRL especially stability, were governed by the amount of SDS, whereby higher concentration of SDS used led to greater NRL stability. However, too much concentration of SDS in the system might cause detrimental effect on the properties of low protein NRL. The effects of additional anionic surfactant namely potassium laurate on the physical properties of low protein NRL and its stabilization were also scrutinized. Characterizations include nitrogen determination by Kjeldahl method, zeta potential, and morphological analysis by Field Emission Scanning Electron Microscopy (FESEM).

  1. Determination of concentration and molar absorptivity of hypochlorous acid and hypobromous acid species by hydrogen peroxide titration

    NASA Astrophysics Data System (ADS)

    Uehara, H.; Arakaki, T.

    2017-12-01

    Hypochlorous acid and hypobromous acid (abbreviated as "HypoX acids") are the main ingredients of bleaching and bactericides. The HypoX acids change their chemical forms depending on environmental factors such as pH and various chemical reactions. For example, it has been reported that hypobromite ion in water changes to carcinogenic bromate by photochemical reaction with ultraviolet light. In this study, concentrations of HypoX acids were determined by UV-VIS absorbance measurement utilizing the fact that HypoX acids react with hydrogen peroxide and do not co-exist in the solution. The method for determining the concentration by titration with hydrogen peroxide can be carried out simpler and more efficiently than the DPD method or the current titration method generally used for chlorine concentration measurement. Molar absorptivity between 250 - 500 nm of HypoX acids, including their conjugate base species, was determined by solving theoretical acid-base formula including molar fraction of each chemical species at various pHs. Molar absorptivity of OCl- and OBr- between 250 - 500 nm was determined based on the concentrations obtained from titration with hydrogen peroxide and absorbance at pH > 10, where OCl- and OBr- dominate. Furthermore, the HypoX acids solutions were irradiated with a solar simulator, and the photolysis rate constants were obtained. Based on those values, the half-lives were calculated and the behavior of HypoX acids in the environment was elucidated.

  2. Interaction of inorganic anions with iron-mineral adsorbents in aqueous media--a review.

    PubMed

    Kumar, Eva; Bhatnagar, Amit; Hogland, William; Marques, Marcia; Sillanpää, Mika

    2014-01-01

    A number of inorganic anions (e.g., nitrate, fluoride, bromate, phosphate, and perchlorate) have been reported in alarming concentrations in numerous drinking water sources around the world. Their presence even in very low concentrations may cause serious environmental and health related problems. Due to the presence and significance of iron minerals in the natural aquatic environment and increasing application of iron in water treatment, the knowledge of the structure of iron and iron minerals and their interactions with aquatic pollutants, especially inorganic anions in water are of great importance. Iron minerals have been known since long as potential adsorbents for the removal of inorganic anions from aqueous phase. The chemistry of iron and iron minerals reactions in water is complex. The adsorption ability of iron and iron minerals towards inorganic anions is influenced by several factors such as, surface characteristics of the adsorbent (surface area, density, pore volume, porosity, pore size distribution, pHpzc, purity), pH of the solution, and ionic strength. Furthermore, the physico-chemical properties of inorganic anions (pore size, ionic radius, bulk diffusion coefficient) also significantly influence the adsorption process. The aim of this paper is to provide an overview of the properties of iron and iron minerals and their reactivity with some important inorganic anionic contaminants present in water. It also summarizes the usage of iron and iron minerals in water treatment technology. © 2013.

  3. Outer-sphere interaction of aluminum and gallium solvates with competitive anions in 1,2-propanediol solutions

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

    Petrosyants, S.P.; Buslaeva, E.R.

    1986-04-01

    The interaction of aluminum and gallium solvates with ..pi..-acid ligand in 1,2-propanediol solutions has been investigated. The formation of associates of hexacoordinate aluminum solvates depends on the solvation of the anions in the bulk of the solution or on the faces of the solvento complexes. In the case of gallium the association of the solvates with the anions is determined by two factors: the existence of a configurational equilibrium for the solvento complexes and the preferential solvation of the competitive ..pi..-acid ligands.

  4. The efficiency of Amberjet 4200 resin in removing nitrate in the presence of competitive anions from Shiraz drinking water.

    PubMed

    Dehghani, M; Haghighi, A Binaee; Zamanian, Z

    2010-06-01

    The aim of this research is to study the feasibility of removing nitrates from water by means of anion exchange. In the purposed work an attempt was made to utilize strong basic anion resin to remove nitrate in the presence of competitive anion. Amberjet Cl- 4200 ion exchange resin was used in a batch scale. The fixation rate of nitrate without the presences of any competitive anion was almost constant (94.60-96.43) when the nitrate concentrations are in the range of 100-150 mg L(-1). The fixation rate of nitrate in the presences of two competitive anions (sulphate and chloride) was reduced to 82% when the concentration of nitrate was 100 mg L(-1).

  5. Anions in Cometary Comae

    NASA Technical Reports Server (NTRS)

    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.

  6. Supramolecular architectures with π-acidic 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine cavities: role of anion-π interactions in the remarkable stability of Fe(II) metallacycles in solution.

    PubMed

    Chifotides, Helen T; Giles, Ian D; Dunbar, Kim R

    2013-02-27

    The comprehensive investigation reported herein provides compelling evidence that anion-π interactions are the main driving force in the formation of self-assembled Fe(II)-templated metallacycles with bptz [3,6-bis(2-pyridyl)-1,2,4,5-tetrazine] in high yields. It was demonstrated by X-ray crystallography, (1)H NMR, solution and solid-state MAS (19)F NMR spectroscopies, CV and MS studies that the anions [X](-) = [BF(4)](-), [ClO(4)](-) and the anions [Y](-) = [SbF(6)](-), [AsF(6)](-), [PF(6)](-) template molecular squares [Fe(4)(bptz)(4)(CH(3)CN)(8)][X](8) and pentagons [Fe(5)(bptz)(5)(CH(3)CN)(10)][Y](10), respectively. The X-ray structures of [{Fe(4)(bptz)(4)(CH(3)CN)(8)}⊂BF(4)][BF(4)](7) and [{Fe(5)(bptz)(5)(CH(3)CN)(10)}⊂2SbF(6)][SbF(6)](8) revealed that the [BF(4)](-) and [SbF(6)](-) anions occupy the π-acidic cavities, establishing close directional F···C(tetrazine) contacts with the tetrazine rings that are by ~0.4 Å shorter than the sum of the F···C van der Waals radii (ΣR(vdW) F···C = 3.17 Å). The number and strength of F···C(tetrazine) contacts are maximized; the F···C(tetrazine) distances and anion positioning versus the polygon opposing tetrazine rings are in agreement with DFT calculations for C(2)N(4)R(2)···[X](-)···C(2)N(4)R(2) (R = F, CN; [X](-) = [BF(4)](-), [PF(6)](-)). In unprecedented solid-state (19)F MAS NMR studies, the templating anions, engaged in anion-π interactions in the solid state, exhibit downfield chemical shifts Δδ((19)F) ≈ 3.5-4.0 ppm versus peripheral anions. NMR, CV, and MS studies also establish that the Fe(II) metallacycles remain intact in solution. Additionally, interconversion studies between the Fe(II) metallacycles in solution, monitored by (1)H NMR spectroscopy, underscore the remarkable stability of the metallapentacycles [Fe(5)(bptz)(5)(CH(3)CN)(10)][PF(6)](10) ≪ [Fe(5)(bptz)(5)(CH(3)CN)(10)][SbF(6)](10) < [Fe(5)(bptz)(5)(CH(3)CN)(10)][AsF(6)](10) versus [Fe(4)(bptz)(4)(CH(3)CN)(8

  7. Tandem mass spectrometry characteristics of polyester anions and cations formed by electrospray ionization.

    PubMed

    Arnould, Mark A; Buehner, Rita W; Wesdemiotis, Chrys; Vargas, Rafael

    2005-01-01

    Electrospray ionization of polyesters composed of isophthalic acid and neopentyl glycol produces carboxylate anions in negative mode and mainly sodium ion adducts in positive mode. A tandem mass spectrometry (MS/MS) study of these ions in a quadrupole ion trap shows that the collisionally activated dissociation pathways of the anions are simpler than those of the corresponding cations. Charge-remote fragmentations predominate in both cases, but the spectra obtained in negative mode are devoid of the complicating cation exchange observed in positive mode. MS/MS of the Na(+) adducts gives rise to a greater number of fragments but not necessarily more structural information. In either positive or negative mode, polyester oligomers with different end groups fragment by similar mechanisms. The observed fragments are consistent with rearrangements initiated by the end groups. Single-stage ESI mass spectra also are more complex in positive mode because of extensive H/Na substitutions; this is also true for matrix-assisted laser desorption ionization (MALDI) mass spectra. Hence, formation and analysis of anions might be the method of choice for determining block length, end group structure and copolymer sequence, provided the polyester contains at least one carboxylic acid end group that is ionizable to anions.

  8. Growth inhibition of fungus Phycomyces blakesleeanus by anion channel inhibitors anthracene-9-carboxylic and niflumic acid attained through decrease in cellular respiration and energy metabolites.

    PubMed

    Stanić, Marina; Križak, Strahinja; Jovanović, Mirna; Pajić, Tanja; Ćirić, Ana; Žižić, Milan; Zakrzewska, Joanna; Antić, Tijana Cvetić; Todorović, Nataša; Živić, Miroslav

    2017-03-01

    Increasing resistance of fungal strains to known fungicides has prompted identification of new candidates for fungicides among substances previously used for other purposes. We have tested the effects of known anion channel inhibitors anthracene-9-carboxylic acid (A9C) and niflumic acid (NFA) on growth, energy metabolism and anionic current of mycelium of fungus Phycomyces blakesleeanus. Both inhibitors significantly decreased growth and respiration of mycelium, but complete inhibition was only achieved by 100 and 500 µM NFA for growth and respiration, respectively. A9C had no effect on respiration of human NCI-H460 cell line and very little effect on cucumber root sprout clippings, which nominates this inhibitor for further investigation as a potential new fungicide. Effects of A9C and NFA on respiration of isolated mitochondria of P. blakesleeanus were significantly smaller, which indicates that their inhibitory effect on respiration of mycelium is indirect. NMR spectroscopy showed that both A9C and NFA decrease the levels of ATP and polyphosphates in the mycelium of P. blakesleeanus, but only A9C caused intracellular acidification. Outwardly rectifying, fast inactivating instantaneous anionic current (ORIC) was also reduced to 33±5 and 21±3 % of its pre-treatment size by A9C and NFA, respectively, but only in the absence of ATP. It can be assumed from our results that the regulation of ORIC is tightly linked to cellular energy metabolism in P. blakesleeanus, and the decrease in ATP and polyphosphate levels could be a direct cause of growth inhibition.

  9. Dependence of Non-Prestonian Behavior of Ceria Slurry with Anionic Surfactant on Abrasive Concentration and Size in Shallow Trench Isolation Chemical Mechanical Polishing

    NASA Astrophysics Data System (ADS)

    Kang, Hyun‑Goo; Kim, Dae‑Hyeong; Katoh, Takeo; Kim, Sung‑Jun; Paik, Ungyu; Park, Jea‑Gun

    2006-05-01

    The dependencies of the non-Prestonian behavior of ceria slurry with anionic surfactant on the size and concentration of abrasive particles were investigated by performing chemical mechanical polishing (CMP) experiments using blanket wafers. We found that not only the abrasive size but also the abrasive concentration with surfactant addition influences the non-Prestonian behavior. Such behavior is clearly exhibited with small abrasive sizes and a higher concentrations of abrasives with surfactant addition, because the abrasive particles can locally contact the film surface more effectively with applied pressure. We introduce a factor to quantify these relations with the non-Prestonian behavior of a slurry. For ceria slurry, this non-Prestonian factor, βNP, was determined to be almost independent of the abrasive concentration for a larger size and a smaller weight conentration of abrasive particles, but it increased with the surfactant concentration for a smaller size and a higher concentration of abrasives with surfactant addition.

  10. Determination of selected anions in water by ion chromatography

    USGS Publications Warehouse

    Fishman, Marvin J.; Pyen, Grace

    1979-01-01

    Ion chromatography is a rapid, sensitive, precise, and accurate method for the determination of major anions in rain water and surface waters. Simultaneous analyses of a single sample for bromide, chloride, fluoride, nitrate, nitrite, orthophosphate, and sulfate require approximately 20 minutes to obtain a chromatogram.Minimum detection limits range from 0.01 milligrams per liter for fluoride to 0.20 milligrams per liter for chloride and sulfate. Percent relative standard deviations were less than nine percent for all anions except nitrite in Standard Reference Water Samples. Only one reference sample contained nitrite and its concentration was near the minimum level of detection. Similar precision was found for chloride, nitrate, and sulfate at concentrations less than 5 milligrams per liter in rainfall samples. Precision for fluoride ranged from 12 to 22 percent, but is attributed to the low concentrations in these samples. The other anions were not detected.To determine accuracy of results, several samples were spiked with known concentrations of fluoride, chloride, nitrate, and sulfate; recoveries ranged from 96 to 103 percent. Known amounts of bromide and phosphate were added, separately, to several other waters, which contained bromide or phosphate. Recovery of added bromide and phosphate ranged from approximately 95 to 104 percent. No recovery data were obtained for nitrite.Chloride, nitrate, nitrite, orthophosphate, and sulfate, in several samples, were also determined independently by automated colorimetric procedures. An automated ion-selective electrode method was used to determine fluoride. Results are in agreement with results obtained by ion chromatography.

  11. PHASE BEHAVIOR OF WATER/PERCHLOROETHYLENE/ANIONIC SURFACTANT SYSTEMS

    EPA Science Inventory

    Winsor Type I (o/w), Type II (w/o), and Type III (middle phase) microemulsions have been generated for water and perchloroethylene (PCE) in combination with anionic surfactants and the appropriate electrolyte concentration. The surfactant formulation was a combination of sodium d...

  12. Squarylium-based chromogenic anion sensors.

    PubMed

    Lee, Eun-Mi; Gwon, Seon-Yeong; Son, Young-A; Kim, Sung-Hoon

    2012-09-01

    A squarylium (SQ) dye was synthesized by the reaction between squaric acid and 2,3,3-trimethylindolenine and its anion sensing properties were investigated using absorption and emission spectroscopy. This chemosensor exhibited high selectivity for CN(-) as compared with F(-), CH(3)CO(2)(-), Br(-), H(2)PO(4)(-), Cl(-), and NO(3)(-) in acetonitrile, which was attributed to the formation of a 1:1 squarylium:CN(-) coordination complex, the formation of which was supported by the calculated geometry of the complex. Copyright © 2012 Elsevier B.V. All rights reserved.

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

    NASA Astrophysics Data System (ADS)

    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.

  14. A micrometer-sized europium(iii)-organic framework for selective sensing of the Cr2O72- anion and picric acid in water systems.

    PubMed

    He, Hongming; Chen, Si-Hang; Zhang, De-Yu; Hao, Rui; Zhang, Chao; Yang, En-Cui; Zhao, Xiao-Jun

    2017-10-10

    A micrometer-sized europium(iii)-organic framework with asymmetric binuclear metal subunits extended by 4,5-dichlorophthalaten (DCPA), [Eu 2 (H 2 O)(DCPA) 3 ] n , was easily obtained using a reverse microemulsion method. The framework exhibits good dispersibility, excellent thermal and environmental stability and easy regeneration ability. More importantly, the complex displays strong red emission and can selectively and sensitively detect both inorganic Cr 2 O 7 2- anions (K sv = 8.7 × 10 3 M -1 ) and organic picric acid contaminants (K sv = 1.07 × 10 4 M -1 ) in water systems through fluorescence quenching. A luminescent film of 1 was further prepared and successfully used to detect the Cr 2 O 7 2- anion in an aqueous system. These interesting results indicate that the well-dispersed europium(iii)-organic framework can serve as a promising dual-responsive luminescent sensor for environmental pollutant monitoring.

  15. Concentration variations of amino acids in mammalian fossils: effects of diagenesis and the implications for amino acid racemization analysis

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

    Blackwell, B.; Rutter, N.W.

    Detailed amino acid analysis of bones, teeth, and antler from several mammal species have shown that concentrations of several amino acids can be related to three factors: type of material analyzed, diagenetic alteration of the material, and relative age of the fossil. Concentrations of several amino acids are significantly different in enamel compared to those of dentine or cement. This can be used to check that no contamination of one material by another has occurred, which is critical for using the data for amino acid dating, since all three materials have different racemization rates for some acids. With increased inmore » growth of secondary minerals, generally reduced amino acid concentrations are observed. Interacid ratios and concentrations vary significantly the norms expected for the type of material with increasing degrees of alteration. These effects can be linked to abnormal racemization ratios observed in the same samples. Therefore, abnormal concentrations and/or interacid ratios can be used to detect samples in which the D/L amino acid ratios otherwise appear normal, thereby insuring better accuracy of amino acid racemization analysis. For unaltered fossils, with increasing sample age regardless the type of material, some amino acids steadily degrade, while others actually increase in concentration initially due to their generation as by-products of decay. Preliminary studies indicate that this progressive alteration can used to complement racemization data for determining relative stratigraphic sequences.« less

  16. CATALYTIC PROMOTION OF THE ADSORPTION OF VANADIUM ON AN ANIONIC EXCHANGE RESIN

    DOEpatents

    Bailes, R.H.; Ellis, D.A.

    1958-08-26

    An improvement in the process for the recovery of vanadium from acidic phosphatic solutions is presented. In this process the vanadium is first oxidized to the pentavaleat state, and is then separated by contacting such solutions with an anion exchange resin whereby adsorption of the complexed pentavalent vanadium is effected. The improvement lies in the fact that adsorp tion of the vanadium complex by the anion exchange resin is promoted and improved by providing fiuoride ions in solution to be contacted.

  17. Ca2+ and Mg2+-enhanced reduction of arsenazo III to its anion free radical metabolite and generation of superoxide anion by an outer mitochondrial membrane azoreductase.

    PubMed

    Moreno, S N; Mason, R P; Docampo, R

    1984-12-10

    At the concentrations usually employed as a Ca2+ indicator, arsenazo III underwent a one-electron reduction by rat liver mitochondria to produce an azo anion radical as demonstrated by electron-spin resonance spectroscopy. Either NADH or NADPH could serve as a source of reducing equivalents for the production of this free radical by intact rat liver mitochondria. Under aerobic conditions, addition of arsenazo III to rat liver mitochondria produced an increase in electron flow from NAD(P)H to molecular oxygen, generating superoxide anion. NAD(P)H generated from endogenous mitochondrial NAD(P)+ by intramitochondrial reactions could not be used for the NAD(P)H azoreductase reaction unless the mitochondria were solubilized by detergent or anaerobiosis. In addition, NAD(P)H azoreductase activity was higher in the crude outer mitochondrial membrane fraction than in mitoplasts and intact mitochondria. The steady-state concentration of the azo anion radical and the arsenazo III-stimulated cyanide-insensitive oxygen consumption were enhanced by calcium and magnesium, suggesting that, in addition to an enhanced azo anion radical-stabilization by complexation with the metal ions, enhanced reduction of arsenazo III also occurred. Accordingly, addition of cations to crude outer mitochondrial membrane preparations increased arsenazo III-stimulated cyanide-insensitive O2 consumption, H2O2 formation, and NAD(P)H oxidation. Antipyrylazo III was much less effective than arsenazo III in increasing superoxide anion formation by rat liver mitochondria and gave a much weaker electron spin resonance spectrum of an azo anion radical. These results provide direct evidence of an azoreductase activity associated with the outer mitochondrial membrane and of a stimulation of arsenazo III reduction by cations.

  18. Molecular structure investigation of neutral, dimer and anion forms of 3,4-pyridinedicarboxylic acid: a combined experimental and theoretical study.

    PubMed

    Karabacak, Mehmet; Bilgili, Sibel; Atac, Ahmet

    2015-01-25

    In this study, the structural and vibrational analysis of 3,4-pyridinedicarboxylic acid (3,4-PDCA) are presented using experimental techniques as FT-IR, FT-Raman, NMR, UV and quantum chemical calculations. FT-IR and FT-Raman spectra of 3,4-pyridinedicarboxylic acid in the solid phase are recorded in the region 4000-400 cm(-1) and 4000-50 cm(-1), respectively. The geometrical parameters and energies of all different and possible monomer, dimer, anion(-1) and anion(-2) conformers of 3,4-PDCA are obtained from Density Functional Theory (DFT) with B3LYP/6-311++G(d,p) basis set. There are sixteen conformers (C1C16) for this molecule (neutral form). The most stable conformer of 3,4-PDCA is the C1 conformer. The complete assignments are performed on the basis of the total energy distribution (TED) of the vibrational modes calculated with scaled quantum mechanics (SQM) method. (1)H and (13)C NMR spectra are recorded and the chemical shifts are calculated by using DFT/B3LYP methods with 6-311++G(d,p) basis set. The UV absorption spectrum of the studied compound is recorded in the range of 200-400 nm by dissolved in ethanol. The optimized geometric parameters were compared with experimental data via the X-ray results derived from complexes of this molecule. In addition these, molecular electrostatic potential (MEP), thermodynamic and electronic properties, HOMO-LUMO energies and Mulliken atomic charges, are performed. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. CTP:phosphocholine cytidylyltransferase binds anionic phospholipid vesicles in a cross-bridging mode.

    PubMed

    Taneva, Svetla G; Patty, Philipus J; Frisken, Barbara J; Cornell, Rosemary B

    2005-07-05

    CTP:phosphocholine cytidylyltransferase (CCT) catalyzes the rate-limiting step in phosphatidylcholine (PC) synthesis, and its activity is regulated by reversible association with membranes, mediated by an amphipathic helical domain M. Here we describe a new feature of the CCTalpha isoform, vesicle tethering. We show, using dynamic light scattering and transmission electron microscopy, that dimers of CCTalpha can cross-bridge separate vesicles to promote vesicle aggregation. The vesicles contained either class I activators (anionic phospholipids) or the less potent class II activators, which favor nonlamellar phase formation. CCT increased the apparent hydrodynamic radius and polydispersity of anionic phospholipid vesicles even at low CCT concentrations corresponding to only one or two dimers per vesicle. Electron micrographs of negatively stained phosphatidylglycerol (PG) vesicles confirmed CCT-mediated vesicle aggregation. CCT conjugated to colloidal gold accumulated on the vesicle surfaces and in areas of vesicle-vesicle contact. PG vesicle aggregation required both the membrane-binding domain and the intact CCT dimer, suggesting binding of CCT to apposed membranes via the two M domains situated on opposite sides of the dimerization domain. In contrast to the effects on anionic phospholipid vesicles, CCT did not induce aggregation of PC vesicles containing the class II lipids, oleic acid, diacylglycerol, or phosphatidylethanolamine. The different behavior of the two lipid classes reflected differences in measured binding affinity, with only strongly binding phospholipid vesicles being susceptible to CCT-induced aggregation. Our findings suggest a new model for CCTalpha domain organization and membrane interaction, and a potential involvement of the enzyme in cellular events that implicate close apposition of membranes.

  20. Kinetic and thermodynamic studies on the adsorption of anionic surfactant on quaternary ammonium cationic cellulose.

    PubMed

    Zhang, Yuanzhang; Shi, Wenjian; Zhou, Hualan; Fu, Xing; Chen, Xuan

    2010-06-01

    Removal of anionic surfactants from aqueous solutions by adsorption onto quaternary ammonium cationic cellulose (QACC) was investigated. The effects of solution acidity, initial concentration, adsorption time, and temperature on the adsorption of sodium dodecyl-benzene sulfonate (SDBS), sodium lauryl sulfate (SLS), and sodium dodecyl sulfonate (SDS) were studied. The kinetic experimental data fit well with the pseudo-second-order model; the rate constant of the adsorption increased with temperature. The values of apparent activation energy for the adsorption were calculated as ranging from 10.2 to 17.4 kJ/ mol. The adsorption isotherm can be described by the Langmuir isotherm. The values of thermodynamic parameters (deltaH0, deltaS0, and deltaG0) for the adsorption indicated that this process was spontaneous and endothermic. At 318 K, the saturated adsorption capacities of QACC for SDBS, SLS, and SDS were 1.75, 1.53, and 1.39 mmol/g, respectively. The adsorption process was mainly chemisorption and partially physisorption. The results show that QACC is effective for the removal of anionic surfactants.

  1. Organoboron compounds as Lewis acid receptors of fluoride ions in polymeric membranes.

    PubMed

    Jańczyk, Martyna; Adamczyk-Woźniak, Agnieszka; Sporzyński, Andrzej; Wróblewski, Wojciech

    2012-07-06

    Newly synthesized organoboron compounds - 4-octyloxyphenylboronic acid (OPBA) and pinacol ester of 2,4,6-trifluorophenylboronic acid (PE-PBA) - were applied as Lewis acid receptors of fluoride anions. Despite enhanced selectivity, the polymer membrane electrodes containing the lipophilic receptor OPBA exhibited non-Nernstian slopes of the responses toward fluoride ions in acidic conditions. Such behavior was explained by the lability of the B-O bond in the boronic acids, and the OH(-)/F(-) exchange at higher fluoride content in the sample solution. In consequence, the stoichiometry of the OPBA-fluoride complexes in the membrane could vary during the calibration, changing the equilibrium concentration of the primary anion in membrane and providing super-Nernstian responses. The proposed mechanism was supported by (19)F NMR studies, which indicated that the fluoride complexation proceeds more effectively in acidic solution leading mainly to PhBF(3)(-) species. Finally, the performances of the membranes based on the phenylboronic acid pinacol ester, with a more stable B-O bond, were tested. As it was expected, Nernstian fluoride responses were recorded for such membranes with worsened fluoride selectivity. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. The effects of caffeic, coumaric and ferulic acids on proliferation, superoxide production, adhesion and migration of human tumor cells in vitro.

    PubMed

    Nasr Bouzaiene, Nouha; Kilani Jaziri, Soumaya; Kovacic, Hervé; Chekir-Ghedira, Leila; Ghedira, Kamel; Luis, José

    2015-11-05

    Reactive oxygen species are well-known mediators of various biological responses. In this study, we examined the effect of three phenolic acids, caffeic, coumaric and ferulic acids, on superoxide anion production, adhesion and migration of human lung (A549) and colon adenocarcinoma (HT29-D4) cancer cell lines. Proliferation of both tumor cells was inhibited by phenolic acids. Caffeic, coumaric and ferulic acids also significantly inhibited superoxide production in A549 and HT29-D4 cells. Superoxide anion production decreased by 92% and 77% at the highest tested concentration (200 µM) of caffeic acid in A549 and HT29-D4 cell lines respectively. Furthermore, A549 and HT29-D4 cell adhesion was reduced by 77.9% and 79.8% respectively at the higher tested concentration of ferulic acid (200 µM). Migration assay performed towards A549 cell line, revealed that tested compounds reduced significantly cell migration. At the highest concentration tested (200 µM), the covered surface was 7.7%, 9.5% and 35% for caffeic, coumaric or ferulic acids, respectively. These results demonstrate that caffeic, coumaric and ferulic acids may participate as active ingredients in anticancer agents against lung and colon cancer development, at adhesion and migration steps of tumor progression. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Counting the ions surrounding nucleic acids

    PubMed Central

    2017-01-01

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

  4. Dynamics of Pseudomonas aeruginosa association with anionic hydrogel surfaces in the presence of aqueous divalent-cation salts

    PubMed Central

    Tran, Victoria B.; Sung, Ye Suel; Fleiszig, Suzanne M.J.; Evans, David J.; Radke, C.J.

    2013-01-01

    Binding of bacteria to solid surfaces is complex with many aspects incompletely understood. We investigate Pseudomonas aeruginosa uptake kinetics onto hydrogel surfaces representative of soft-contact lenses made of nonionic poly(2-hydroxyethylmethacrylate) (p-HEMA), anionic poly(methacrylic acid) (p-MAA), and anionic poly(acrylic acid) (p-AA). Using a parallel-plate flow cell under phase-contrast microscopy, we document a kinetic “burst” at the anionic hydrogel surface: dilute aqueous P. aeruginosa first rapidly accumulates and then rapidly depletes. Upon continuing flow, divalent cations in the suspending solution sorb into the hydrogel network causing the previously surface-accumulated bacteria to desorb. The number of bacteria eventually bound to the surface is low compared to the nonionic p-HEMA hydrogel. We propose that the kinetic burst is due to reversible divalent-cation bridging between the anionic bacteria and the negatively charged hydrogel surface. The number of surface bridging sites diminishes as divalent cations impregnate into and collapse the gel. P. aeruginosa association with the surface then falls. Low eventual binding of P. aeruginosa to the anionic hydrogel is ascribed to increased surface hydrophilicity compared to the counterpart nonionic p-HEMA hydrogel. PMID:21723562

  5. Maize ZmALMT2 is a root anion transporter that mediates constitutive root malate efflux

    USDA-ARS?s Scientific Manuscript database

    Aluminum (Al) toxicity is a primary limitation to crop productivity on acid soils throughout the plant. Root efflux of organic acid anions constitutes a mechanism by which plants cope with toxic aluminum (Al) ions on acid soils. In this study, we have characterized ZmALMT2 (a member of aluminum-acti...

  6. Extracellular Determinants of Anion Discrimination of the Cl−/H+ Antiporter Protein CLC-5*

    PubMed Central

    De Stefano, Silvia; Pusch, Michael; Zifarelli, Giovanni

    2011-01-01

    Mammalian CLC proteins comprise both Cl− channels and Cl−/H+ antiporters that carry out fundamental physiological tasks by transporting Cl− across plasma membrane and intracellular compartments. The NO3− over Cl− preference of a plant CLC transporter has been pinpointed to a conserved serine residue located at Scen and it is generally assumed that the other two binding sites of CLCs, Sext and Sin, do not substantially contribute to anion selectivity. Here we show for the Cl−/H+ antiporter CLC-5 that the conserved and extracellularly exposed Lys210 residue is critical to determine the anion specificity for transport activity. In particular, mutations that neutralize or invert the charge at this position reverse the NO3− over Cl− preference of WT CLC-5 at a concentration of 100 mm, but do not modify the coupling stoichiometry with H+. The importance of the electrical charge is shown by chemical modification of K210C with positively charged cysteine-reactive compounds that reintroduce the WT preference for Cl−. At saturating extracellular anion concentrations, neutralization of Lys210 is of little impact on the anion preference, suggesting an important role of Lys210 on the association rate of extracellular anions to Sext. PMID:21921031

  7. High elevation watersheds in the southern Appalachians: indicators of sensitivity to acidic deposition and the potential for restoration through liming

    Treesearch

    Jennifer D. Knoepp; James M. Vose; William A. Jackson; Katherine J. Elliott; Stan Zarnoch

    2016-01-01

    Southern Appalachian high elevation watersheds have deep rocky soils with high organic matter content, different vegetation communities, and receive greater inputs of acidic deposition compared to low elevation sites within the region. Since the implementation of the Clean Air Act Amendment in the 1990s, concentrations of acidic anions in rainfall have...

  8. Short communication: Association of milk fatty acids with early lactation hyperketonemia and elevated concentration of nonesterified fatty acids.

    PubMed

    Mann, S; Nydam, D V; Lock, A L; Overton, T R; McArt, J A A

    2016-07-01

    The objective of our study was to extend the limited research available on the association between concentrations of milk fatty acids and elevated nonesterified fatty acids (NEFA) and β-hydroxybutyrate (BHB) concentrations in early lactation dairy cattle. Measurement of milk fatty acids for detection of cows in excessive negative energy balance has the potential to be incorporated in routine in-line monitoring systems. Blood samples were taken from 84 cows in second or greater lactation 3 times per week between 3 to 14 d in milk. Cows were characterized as hyperketonemic (HYK) if blood BHB concentration was ≥1.2mmol/L at least once and characterized as having elevated concentrations of NEFA (NEFAH) if serum NEFA concentration was ≥1mmol/L at least once. Composition of colostrum and milk fatty acids at wk 2 postpartum was used to investigate the potential diagnostic value of individual fatty acids and fatty acid ratios for the correct classification of cows with NEFA and BHB concentrations above these thresholds, respectively. Receiver operating characteristic (ROC) curves were used to identify thresholds of fatty acid concentration and fatty acid ratios when ROC area under the curve was ≥0.70. Correct classification rate (CCR, %) was calculated as {[(number of true positives + number of true negatives)/total number tested] × 100}. None of the colostrum fatty acids yielded a sufficiently high area under the curve in ROC analysis for the association with HYK and NEFAH. The following fatty acids and fatty acid ratios were identified for an association with NEFAH (threshold, CCR): C15:0 (≤0.65g/100g, 68.3%); cis-9 C16:1 (≥1.85g/100g, 70.7%); cis-9 C18:1 (≥26g/100g, 69.5%), cis-9 C18:1 to C15:0 ratio (≥45, 69.5%); cis-9 C16:1 to C15:0 (≥2.50, 73.2%). Several fatty acids were associated with HYK (threshold, CCR): C6:0 (≤1.68g/100g, 80.5%), C8:0 (≤0.80g/100g, 80.5%), C10:0 (≤1.6g/100g, 79.3%); C12:0 (≤1.42g/100g, 82.9%); C14:0 (≤6.10g/100g, 84

  9. EFFECT OF INORGANIC CATIONS ON BACTERICIDAL ACTIVITY OF ANIONIC SURFACTANTS

    PubMed Central

    Voss, J. G.

    1963-01-01

    Voss, J. G. (Procter & Gamble Co., Cincinnati, Ohio). Effect of inorganic cations on bactericidal activity of anionic surfactants. J. Bacteriol. 86:207–211. 1963.—The bactericidal effectiveness of two alkyl benzene sulfonates and of three other types of anionic surfactants against Staphylococcus aureus is increased in the presence of low concentrations of divalent cations, especially alkaline earths and metals of group IIB of the periodic table. The cations may act by decreasing the negative charge at the cell surface and increasing adsorption of the surfactant anions, leading to damage to the cytoplasmic membrane and death of the cell. Increased adsorption of surfactant is also found with Escherichia coli, but does not lead to death of the cell. PMID:14058942

  10. Optimization of the separation of lysergic acid diethylamide in urine by a sweeping technique using micellar electrokinetic chromatography.

    PubMed

    Fang, Ching; Liu, Ju-Tsung; Lin, Cheng-Huang

    2002-07-25

    The separation and on-line concentrations of lysergic acid diethylamide (LSD), iso-lysergic acid diethylamide (iso-LSD) and lysergic acid N,N-methylpropylamide (LAMPA) in human urine were investigated by capillary electrophoresis-fluorescence spectroscopy using sodium dodecyl sulfate (SDS) as an anionic surfactant. A number of parameters such as buffer pH, SDS concentration, Brij-30 concentration and the content of organic solvent used in separation, were optimized. The techniques of sweeping-micellar electrokinetic chromatography (sweeping-MEKC) and cation-selective exhaustive injection-sweep-micellar electrokinetic chromatography (CSEI-sweep-MEKC) were used for determining on-line concentrations. The advantages and disadvantages of this procedure with respect to sensitivity, precision and simplicity are discussed and compared. Copyright 2002 Elsevier Science BV.

  11. Orphenadrinium picrate picric acid.

    PubMed

    Fun, Hoong-Kun; Hemamalini, Madhukar; Siddaraju, B P; Yathirajan, H S; Narayana, B

    2010-02-24

    The asymmetric unit of the title compound N,N-dimethyl-2-[(2-methyl-phen-yl)phenyl-meth-oxy]ethanaminium picrate picric acid, C(18)H(24)NO(+)·C(6)H(2)N(3)O(7) (-)·C(6)H(3)N(3)O(7), contains one orphenadrinium cation, one picrate anion and one picric acid mol-ecule. In the orphenadrine cation, the two aromatic rings form a dihedral angle of 70.30 (7)°. There is an intra-molecular O-H⋯O hydrogen bond in the picric acid mol-ecule, which generates an S(6) ring motif. In the crystal structure, the orphenadrine cations, picrate anions and picric acid mol-ecules are connected by strong inter-molecular N-H⋯O hydrogen bonds, π⋯π inter-actions between the benzene rings of cations and anions [centroid-centroid distance = 3.5603 (9) Å] and weak C-H⋯O hydrogen bonds, forming a three-dimensional network.

  12. [What is the contribution of Stewart's concept in acid-base disorders analysis?].

    PubMed

    Quintard, H; Hubert, S; Ichai, C

    2007-05-01

    To explain the different approaches for interpreting acid-base disorders; to develop the Stewart model which offers some advantages for the pathophysiological understanding and the clinical interpretation of acid-base imbalances. Record of french and english references from Medline data base. The keywords were: acid-base balance, hyperchloremic acidosis, metabolic acidosis, strong ion difference, strong ion gap. Data were selected including prospective and retrospective studies, reviews, and case reports. Acid-base disorders are commonly analysed by using the traditional Henderson-Hasselbalch approach which attributes the variations in plasma pH to the modifications in plasma bicarbonates or PaCO2. However, this approach seems to be inadequate because bicarbonates and PaCO2 are completely dependent. Moreover, it does not consider the role of weak acids such as albuminate, in the determination of plasma pH value. According to the Stewart concept, plasma pH results from the degree of plasma water dissociation which is determined by 3 independent variables: 1) strong ion difference (SID) which is the difference between all the strong plasma cations and anions; 2) quantity of plasma weak acids; 3) PaCO2. Thus, metabolic acid-base disorders are always induced by a variation in SID (decreased in acidosis) or in weak acids (increased in acidosis), whereas respiratory disorders remains the consequence of a change in PaCO2. These pathophysiological considerations are important to analyse complex acid-base imbalances in critically ill patients. For example, due to a decrease in weak acids, hypoalbuminemia increases SID which may counter-balance a decrease in pH and an elevated anion gap. Thus if using only traditional tools, hypoalbuminemia may mask a metabolic acidosis, because of a normal pH and a normal anion gap. In this case, the association of metabolic acidosis and alkalosis is only expressed by respectively a decreased SID and a decreased weak acids concentration

  13. [Ion chromatography of L-ascorbic acid, sulfite and thiosulfate using their postcolumn reactions with cerium (IV) and fluorescence detection of cerium (III)].

    PubMed

    Chen, Q; Hu, K; Miura, Y

    1999-09-01

    An ion chromatographic method was used to separate the species of L-ascorbic acid, sulfite and thiosulfate in their mixtures. This method is based on the separation of each anion in their mixtures by using a separation column, and then on the fluorimetric measurement of cerium (III) formed by a postcolumn reaction of cerium (IV) with the species of L-ascorbic acid, sulfite and thiosulfate in the effluent. The optimal conditions for separating and determining the above three species have been established. By using a 3 mmol/L carbonate eluent, the species of L-ascorbic acid, sulfite and thiosulfate could be eluted at the proper retention times of 1.7, 2.6 and 5.0 min, respectively, and these three anions could be separated completely. The effects of the concentrations of cerium (IV) and sulfuric acid in the postcolumn reaction solution on the chromatographic peak-height were tested in order to obtain the optimal peak-height. It was found that the peak-height at first increases rapidly with an increase in the concentration of cerium (IV) and sulfuric acid respectively up to a certain concertation, then increases slowly. These critical concentrations of cerium (IV) and sulfuric acid also depend on the amount of the analyte injected. Meanwhile the baseline signals of the sepectra increase with an increase in the concentration of cerium (IV). Some concentrations above the critical concentration of sulfuric acid could be selected as the optimal concentration of sulfuric acid, but the concentration of cerium (IV) should be optimized by establishing a compromise between the higher peak-height and the lower baseline signal. The detection limit of this method was found to be 1 mumol/L for thiosulfate when an amount of 100 microL analyte was injected.

  14. Congo red adsorption from aqueous solutions by using chitosan hydrogel beads impregnated with nonionic or anionic surfactant.

    PubMed

    Chatterjee, Sudipta; Lee, Dae S; Lee, Min W; Woo, Seung H

    2009-09-01

    The adsorption performance of CS beads impregnated with triton X-100 (TX-100) as a nonionic surfactant and sodium dodecyl sulfate (SDS) as an anionic surfactant was investigated for the removal of anionic dye (congo red) from aqueous solution. While the adsorption capacity of CS/TX-100 beads was enhanced at all concentrations of TX-100 (0.005-0.1%), the increase in the concentration of SDS above 0.01% in the CS/SDS beads gradually reduced the adsorption capacity of the beads. Equilibrium adsorption isotherm data indicated a good fit to the Sips isotherm model and a heterogeneous adsorption process. The Sips maximum adsorption capacity in dry weight of the CS/TX-100 beads was 378.79 mg/g and 318.47 mg/g for the CS/SDS beads, higher than the 223.25mg/g of the CS beads. Modification of CS beads by impregnation with nonionic surfactant, or even anionic surfactant, at low concentrations is a possible way to enhance adsorption of anionic dye.

  15. Effect of detergents, trypsin and unsaturated fatty acids on latent loquat fruit polyphenol oxidase: basis for the enzyme's activity regulation.

    PubMed

    Sellés-Marchart, Susana; Casado-Vela, Juan; Bru-Martínez, Roque

    2007-08-15

    The effects of detergents, trypsin and fatty acids on structural and functional properties of a pure loquat fruit latent polyphenol oxidase have been studied in relation to its regulation. Anionic detergents activated PPO at pH 6.0 below critical micelle concentration (cmc), but inhibited at pH 4.5 well above cmc. This behavior is due to a detergent-induced pH profile alkaline shift, accompanied by changes of intrinsic fluorescence of the protein. Gel filtration experiments demonstrate the formation of PPO-SDS mixed micelles. Partial PPO proteolysis suggest that latent PPO losses an SDS micelle-interacting region but conserves an SDS monomer-interacting site. Unsaturated fatty acids inhibit PPO at pH 4.5, the strongest being linolenic acid while the weakest was gamma-linolenic acid for both, the native and the trypsin-treated PPO. Down-regulation of PPO activity by anionic amphiphiles is discussed based on both, the pH profile shift induced upon anionic amphiphile binding and the PPO interaction with negatively charged membranes.

  16. Organosulfates and organic acids in Arctic aerosols: speciation, annual variation and concentration levels

    NASA Astrophysics Data System (ADS)

    Hansen, A. M. K.; Kristensen, K.; Nguyen, Q. T.; Zare, A.; Cozzi, F.; Nøjgaard, J. K.; Skov, H.; Brandt, J.; Christensen, J. H.; Ström, J.; Tunved, P.; Krejci, R.; Glasius, M.

    2014-02-01

    Sources, composition and occurrence of secondary organic aerosols (SOA) in the Arctic were investigated at Zeppelin Mountain, Svalbard, and Station Nord, northeast Greenland, during the full annual cycle of 2008 and 2010 respectively. We focused on the speciation of three types of SOA tracers: organic acids, organosulfates and nitrooxy organosulfates from both anthropogenic and biogenic precursors, here presenting organosulfate concentrations and compositions during a full annual cycle and chemical speciation of organosulfates in Arctic aerosols for the first time. Aerosol samples were analysed using High Performance Liquid Chromatography coupled to a quadrupole Time-of-Flight mass spectrometer (HPLC-q-TOF-MS). A total of 11 organic acids (terpenylic acid, benzoic acid, phthalic acid, pinic acid, suberic acid, azelaic acid, adipic acid, pimelic acid, pinonic acid, diaterpenylic acid acetate (DTAA) and 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA)), 12 organosulfates and one nitrooxy organosulfate were identified at the two sites. Six out of the 12 organosulfates are reported for the first time. Concentrations of organosulfates follow a distinct annual pattern at Station Nord, where high concentration were observed in late winter and early spring, with a mean total concentration of 47 (±14) ng m-3, accounting for 7 (±2)% of total organic matter, contrary to a considerably lower organosulfate mean concentration of 2 (±3) ng m-3 (accounting for 1 (±1)% of total organic matter) observed during the rest of the year. The organic acids followed the same temporal trend as the organosulfates at Station Nord; however the variations in organic acid concentrations were less pronounced, with a total mean organic acid concentration of 11.5 (±4) ng m-3 (accounting for 1.7 (±0.6)% of total organic matter) in late winter and early spring, and 2.2 (±1) ng m-3 (accounting for 0.9 (±0.4)% of total organic matter) during the rest of the year. At Zeppelin Mountain

  17. Study of Synthesis Polyethylene glycol oleate Sulfonated as an Anionic Surfactant for Enhanced Oil Recovery (EOR)

    NASA Astrophysics Data System (ADS)

    Sampora, Yulianti; Juwono, Ariadne L.; Haryono, Agus; Irawan, Yan

    2017-11-01

    Mechanical Enhanced Oil Recovery (EOR) through chemical injection is using an anionic surfactant to improve the recovery of oil residues, particularly in a reservoir area that has certain characteristics. This case led the authors to conduct research on the synthesis of an anionic surfactant based on oleic acid and polyethylene glycol 400 that could be applied as a chemical injection. In this work, we investigate the sulfonation of Polyethylene glycol oleate (PDO) in a sulfuric acid agent. PDO in this experiment was derived from Indonesian palm oil. Variation of mole reactant and reaction time have been studied. The surfactant has been characterized by measuring the interfacial tension, acid value, ester value, saponification value, iodine value, Fourier Transform Infrared (FTIR), and particle size analyzer. There is a new peak at 1170-1178 cm-1 indicating that S=O bond has formed. PDO sulfonate exhibits good surface activity due to interfacial tension of 0,003 mN/m. Thus, polyethylene glycol oleate sulfonate was successfully synthesized and it could be useful as a novel an anionic surfactant.

  18. Removal of dissolved organic matter by anion exchange: Effect of dissolved organic matter properties

    USGS Publications Warehouse

    Boyer, T.H.; Singer, P.C.; Aiken, G.R.

    2008-01-01

    Ten isolates of aquatic dissolved organic matter (DOM) were evaluated to determine the effect that chemical properties of the DOM, such as charge density, aromaticity, and molecular weight, have on DOM removal by anion exchange. The DOM isolates were characterized asterrestrial, microbial, or intermediate humic substances or transphilic acids. All anion exchange experiments were conducted using a magnetic ion exchange (MIEX) resin. The charge density of the DOM isolates, determined by direct potentiometric titration, was fundamental to quantifying the stoichiometry of the anion exchange mechanism. The results clearly show that all DOM isolates were removed by anion exchange; however, differences among the DOM isolates did influence their removal by MIEX resin. In particular, MIEX resin had the greatest affinity for DOM with high charge density and the least affinity for DOM with low charge density and low aromaticity. This work illustrates that the chemical characteristics of DOM and solution conditions must be considered when evaluating anion exchange treatment for the removal of DOM. ?? 2008 American Chemical Society.

  19. Organosulfates and organic acids in Arctic aerosols: speciation, annual variation and concentration levels

    NASA Astrophysics Data System (ADS)

    Hansen, A. M. K.; Kristensen, K.; Nguyen, Q. T.; Zare, A.; Cozzi, F.; Nøjgaard, J. K.; Skov, H.; Brandt, J.; Christensen, J. H.; Ström, J.; Tunved, P.; Krejci, R.; Glasius, M.

    2014-08-01

    Sources, composition and occurrence of secondary organic aerosols in the Arctic were investigated at Zeppelin Mountain, Svalbard, and Station Nord, northeastern Greenland, during the full annual cycle of 2008 and 2010, respectively. Speciation of organic acids, organosulfates and nitrooxy organosulfates - from both anthropogenic and biogenic precursors were in focus. A total of 11 organic acids (terpenylic acid, benzoic acid, phthalic acid, pinic acid, suberic acid, azelaic acid, adipic acid, pimelic acid, pinonic acid, diaterpenylic acid acetate and 3-methyl-1,2,3-butanetricarboxylic acid), 12 organosulfates and 1 nitrooxy organosulfate were identified in aerosol samples from the two sites using a high-performance liquid chromatograph (HPLC) coupled to a quadrupole Time-of-Flight mass spectrometer. At Station Nord, compound concentrations followed a distinct annual pattern, where high mean concentrations of organosulfates (47 ± 14 ng m-3) and organic acids (11.5 ± 4 ng m-3) were observed in January, February and March, contrary to considerably lower mean concentrations of organosulfates (2 ± 3 ng m-3) and organic acids (2.2 ± 1 ng m-3) observed during the rest of the year. At Zeppelin Mountain, organosulfate and organic acid concentrations remained relatively constant during most of the year at a mean concentration of 15 ± 4 ng m-3 and 3.9 ± 1 ng m-3, respectively. However during four weeks of spring, remarkably higher concentrations of total organosulfates (23-36 ng m-3) and total organic acids (7-10 ng m-3) were observed. Elevated organosulfate and organic acid concentrations coincided with the Arctic haze period at both stations, where northern Eurasia was identified as the main source region. Air mass transport from northern Eurasia to Zeppelin Mountain was associated with a 100% increase in the number of detected organosulfate species compared with periods of air mass transport from the Arctic Ocean, Scandinavia and Greenland. The results from this

  20. Effects of running the Bostom Marathon on plasma concentrations of large neutral amino acids

    NASA Technical Reports Server (NTRS)

    Conlay, L. A.; Wurtman, R. J.; Lopez G-Coviella, I.; Blusztajn, J. K.; Vacanti, C. A.; Logue, M.; During, M.; Caballero, B.; Maher, T. J.; Evoniuk, G.

    1989-01-01

    Plasma large neutral amino acid concentrations were measured in thirty-seven subjects before and after completing the Boston Marathon. Concentrations of tyrosine, phenylalanine, and methionine increased, as did their 'plasma ratios' (i.e., the ratio of each amino acid's concentration to the summed plasma concentrations of the other large neutral amino acids which compete with it for brain uptake). No changes were noted in the plasma concentrations of tryptophan, leucine, isoleucine, nor valine; however, the 'plasma ratios' of valine, leucine, and isoleucine all decreased. These changes in plasma amino acid patterns may influence neurotransmitter synthesis.

  1. Handling of the homocysteine S-conjugate of methylmercury by renal epithelial cells: role of organic anion transporter 1 and amino acid transporters.

    PubMed

    Zalups, Rudolfs K; Ahmad, Sarfaraz

    2005-11-01

    Recently, the activity of the organic anion transporter 1 (OAT1) protein has been implicated in the basolateral uptake of inorganic mercuric species in renal proximal tubular cells. Unfortunately, very little is known about the role of OAT1 in the renal epithelial transport of organic forms of mercury, such as methylmercury (CH(3)Hg(+)). Homocysteine (Hcy) S-conjugates of methylmercury [(S)-(3-amino-3-carboxypropylthio)(methyl)mercury (CH(3)Hg-Hcy)] have been identified recently as being potentially important biologically relevant forms of mercury. Thus, the present study was designed to characterize the transport of CH(3)Hg-Hcy in Madin-Darby canine kidney (MDCK) cells (which are derived from the distal nephron) that were transfected stably with the human isoform of OAT1 (hOAT1). Data on saturation kinetics, time dependence, substrate specificity, and temperature dependence demonstrated that CH(3)Hg-Hcy is a transportable substrate of hOAT1. However, substrate-specificity data from the control MDCK cells also showed that CH(3)Hg-Hcy is a substrate of one or more transporter(s) that is/are not hOAT1. Additional findings indicated that at least one amino acid transport system was probably responsible for this transport. It is noteworthy that the activity of amino acid transporters accounted for the greatest level of uptake of CH(3)Hg-Hcy in the hOAT1-expressing cells. Furthermore, rates of survival of the hOAT1-transfected MDCK cells were significantly lower than those of corresponding control MDCK cells when they were exposed to cytotoxic concentrations of CH(3)Hg-Hcy. Collectively, the present data indicate that CH(3)Hg-Hcy is a transportable substrate of OAT1 and amino acid transporters and, thus, is probably a transportable mercuric species taken up in vivo by proximal tubular epithelial cells.

  2. Forced swimming and imipramine modify plasma and brain amino acid concentrations in mice.

    PubMed

    Murakami, Tatsuro; Yamane, Haruka; Tomonaga, Shozo; Furuse, Mitsuhiro

    2009-01-05

    The relationships between monoamine metabolism and forced swimming or antidepressants have been well studied, however information is lacking regarding amino acid metabolism under these conditions. Therefore, the aim of the present study was to investigate the effects of forced swimming and imipramine on amino acid concentrations in plasma, the cerebral cortex and the hypothalamus in mice. Forced swimming caused cerebral cortex concentrations of L-glutamine, L-alanine, and taurine to be increased, while imipramine treatment caused decreased concentrations of L-glutamate, L-alanine, L-tyrosine, L-methionine, and L-ornithine. In the hypothalamus, forced swimming decreased the concentration of L-serine while imipramine treatment caused increased concentration of beta-alanine. Forced swimming caused increased plasma concentration of taurine, while concentrations of L-serine, L-asparagine, L-glutamine and beta-alanine were decreased. Imipramine treatment caused increased plasma concentration of all amino acid, except for L-aspartate and taurine. In conclusion, forced swimming and imipramine treatment modify central and peripheral amino acid metabolism. These results may aid in the identification of amino acids that have antidepressant-like effects, or may help to refine the dosages of antidepressant drugs.

  3. Extraction of steroidal glucosiduronic acids from aqueous solutions by anionic liquid ion-exchangers

    PubMed Central

    Mattox, Vernon R.; Litwiller, Robert D.; Goodrich, June E.

    1972-01-01

    A pilot study on the extraction of three steroidal glucosiduronic acids from water into organic solutions of liquid ion-exchangers is reported. A single extraction of a 0.5mm aqueous solution of either 11-deoxycorticosterone 21-glucosiduronic acid or cortisone 21-glucosiduronic acid with 0.1m-tetraheptylammonium chloride in chloroform took more than 99% of the conjugate into the organic phase; under the same conditions, the very polar conjugate, β-cortol 3-glucosiduronic acid, was extracted to the extent of 43%. The presence of a small amount of chloride, acetate, or sulphate ion in the aqueous phase inhibited extraction, but making the aqueous phase 4.0m with ammonium sulphate promoted extraction strongly. An increase in the concentration of ion-exchanger in the organic phase also promoted extraction. The amount of cortisone 21-glucosiduronic acid extracted by tetraheptylammonium chloride over the pH range of 3.9 to 10.7 was essentially constant. Chloroform solutions of a tertiary, a secondary, or a primary amine hydrochloride also will extract cortisone 21-glucosiduronic acid from water. The various liquid ion exchangers will extract steroidal glucosiduronic acid methyl esters from water into chloroform, although less completely than the corresponding free acids. The extraction of the glucosiduronic acids from water by tetraheptylammonium chloride occurs by an ion-exchange process; extraction of the esters does not involve ion exchange. PMID:5075264

  4. Stability studies for titanium dioxide nanoparticles upon adsorption of Suwannee River humic and fulvic acids and natural organic matter.

    PubMed

    Erhayem, Mohamed; Sohn, Mary

    2014-01-15

    In many studies humic acid, fulvic acid, or natural organic matter is used interchangeably to model the effect of naturally derived organic matter on geochemical processes in the environment. In this study, the term NOOM (naturally occurring organic matter) is used to include both humic and fulvic acids as well as natural organic matter and compares the effect of NOOM type on NOOM removal onto nano-TiO2. In general, regardless of variations in solution chemistry, the order of the percentage of removal of NOOM onto nano-TiO2 was humic acid>natural organic matter>fulvic acid. The order of adsorption constant values of NOOM onto nano-TiO2 was also found to be humic acid>natural organic matter>fulvic acid under all conditions studied. The extent of NOOM removal by nano-TiO2 was enhanced in the presence of the divalent ions, magnesium and calcium, at pH7.8 when compared to the presence of the monovalent ions, sodium and potassium. Also, lower NOOM removal by nano-TiO2 in the presence of sodium salts of dihydrogen phosphate, bicarbonate and nitrate relative to chloride was observed and was likely due to the competition between polyatomic anions and NOOM adsorption onto the surface of nano-TiO2 indicating an anionic effect. Low concentrations of NOOM (10-20 mg L(-1)) destabilized nano-TiO2 in solution, however, the stability of nano-TiO2 increased as the amount of NOOM adsorbed onto nano-TiO2 increased at higher dissolved NOOM concentrations and significant stabilization was seen at 25 mg L(-1) NOOM. Thus, the three fractions of NOOM, humic and fulvic acids and natural organic matter and their concentrations were found to affect nano-TiO2 stability to different degrees although pH dependent trends in cation and anion effects had similar patterns. While the effects of adsorption of these three commonly used types of NOOM onto nanoparticles are similar, there are important differences that can be related to structural differences. © 2013.

  5. Mimicking the cell membrane: bio-inspired simultaneous functions with monovalent anion selectivity and antifouling properties of anion exchange membrane

    PubMed Central

    Zhao, Yan; Liu, Huimin; Tang, Kaini; Jin, Yali; Pan, Jiefeng; der Bruggen, Bart Van; Shen, Jiangnan; Gao, Congjie

    2016-01-01

    A new bio-inspired method was applied in this study to simultaneously improve the monovalent anion selectivity and antifouling properties of anion exchange membranes (AEMs). Three-layer architecture was developed by deposition of polydopamine (PDA) and electro-deposition of N-O-sulfonic acid benzyl chitosan (NSBC). The innermost and outermost layers were PDA with different deposition time. The middle layer was prepared by NSBC. Fourier transform infrared spectroscopy and scanning electron microscopy confirmed that PDA and NSBC were successfully modified on the surfaces of AEMs. The contact angle of the membranes indicated an improved hydrophilicity of the modified membranes. A series of electrodialysis experiments in which Cl−/SO42− separation was studied, demonstrating the monovalent anion selectivity of the samples. The Cl−/SO42− permselectivity of the modified membranes can reach up to 2.20, higher than that of the commercial membrane (only 0.78) during 90 minutes in electrodialysis (ED). The increase value of the resistance of the membranes was also measured to evaluate the antifouling properties. Sodium dodecyl benzene sulfonate (SDBS) was used as the fouling material in the ED process and the membrane area resistance of modified membrane increase value of was only 0.08 Ωcm2 30 minutes later. PMID:27853255

  6. Mimicking the cell membrane: bio-inspired simultaneous functions with monovalent anion selectivity and antifouling properties of anion exchange membrane.

    PubMed

    Zhao, Yan; Liu, Huimin; Tang, Kaini; Jin, Yali; Pan, Jiefeng; der Bruggen, Bart Van; Shen, Jiangnan; Gao, Congjie

    2016-11-17

    A new bio-inspired method was applied in this study to simultaneously improve the monovalent anion selectivity and antifouling properties of anion exchange membranes (AEMs). Three-layer architecture was developed by deposition of polydopamine (PDA) and electro-deposition of N-O-sulfonic acid benzyl chitosan (NSBC). The innermost and outermost layers were PDA with different deposition time. The middle layer was prepared by NSBC. Fourier transform infrared spectroscopy and scanning electron microscopy confirmed that PDA and NSBC were successfully modified on the surfaces of AEMs. The contact angle of the membranes indicated an improved hydrophilicity of the modified membranes. A series of electrodialysis experiments in which Cl - /SO 4 2- separation was studied, demonstrating the monovalent anion selectivity of the samples. The Cl - /SO 4 2- permselectivity of the modified membranes can reach up to 2.20, higher than that of the commercial membrane (only 0.78) during 90 minutes in electrodialysis (ED). The increase value of the resistance of the membranes was also measured to evaluate the antifouling properties. Sodium dodecyl benzene sulfonate (SDBS) was used as the fouling material in the ED process and the membrane area resistance of modified membrane increase value of was only 0.08 Ωcm 2 30 minutes later.

  7. Mimicking the cell membrane: bio-inspired simultaneous functions with monovalent anion selectivity and antifouling properties of anion exchange membrane

    NASA Astrophysics Data System (ADS)

    Zhao, Yan; Liu, Huimin; Tang, Kaini; Jin, Yali; Pan, Jiefeng; der Bruggen, Bart Van; Shen, Jiangnan; Gao, Congjie

    2016-11-01

    A new bio-inspired method was applied in this study to simultaneously improve the monovalent anion selectivity and antifouling properties of anion exchange membranes (AEMs). Three-layer architecture was developed by deposition of polydopamine (PDA) and electro-deposition of N-O-sulfonic acid benzyl chitosan (NSBC). The innermost and outermost layers were PDA with different deposition time. The middle layer was prepared by NSBC. Fourier transform infrared spectroscopy and scanning electron microscopy confirmed that PDA and NSBC were successfully modified on the surfaces of AEMs. The contact angle of the membranes indicated an improved hydrophilicity of the modified membranes. A series of electrodialysis experiments in which Cl-/SO42- separation was studied, demonstrating the monovalent anion selectivity of the samples. The Cl-/SO42- permselectivity of the modified membranes can reach up to 2.20, higher than that of the commercial membrane (only 0.78) during 90 minutes in electrodialysis (ED). The increase value of the resistance of the membranes was also measured to evaluate the antifouling properties. Sodium dodecyl benzene sulfonate (SDBS) was used as the fouling material in the ED process and the membrane area resistance of modified membrane increase value of was only 0.08 Ωcm2 30 minutes later.

  8. Effects on grape amino acid concentration through foliar application of three different elicitors.

    PubMed

    Gutiérrez-Gamboa, G; Portu, J; Santamaría, P; López, R; Garde-Cerdán, T

    2017-09-01

    Elicitors play an important role in the defense against pathogens as an alternative to chemical pesticides by increasing secondary metabolites. Their effect on grape amino acid has been little investigated. Thus, the aim of this research was to study the influence of methyl jasmonate (MeJ), chitosan (CHT), and a yeast extract (YE) on grape amino acid composition, through foliar applications to grapevines. The must amino acid concentration was analyzed by HPLC. The results showed that CHT and YE treatments decreased the must concentration of several amino acids, affecting total amino acid content (from 2364 to 1961, and 1818mg/L, respectively). However, MeJ treatment had a slight effect on grape amino acid content, increasing the concentration of Met (from 8.95 to 12.13mg/L) and Phe (from 7.96 to 9.29mg/L). It seems to be that, the resistance induction through CHT and YE treatments results in physiological costs to grapevines associated with a decrease on grape amino acid concentration. Consequently, MeJ applications, as a viticultural practice, could be a better tool than CHT and YE treatments, because did not affect grape amino acid concentration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Effects of cultivar, fruit number and reflected photosynthetically active radiation on Fragaria x ananassa productivity and fruit ellagic acid and ascorbic acid concentrations.

    PubMed

    Atkinson, C J; Dodds, P A A; Ford, Y Y; Le Mière, J; Taylor, J M; Blake, P S; Paul, N

    2006-03-01

    A number of strawberry varieties were surveyed for their total ellagic acid concentration, and attempts were made to determine if ellagic acid and ascorbic acid concentrations of two strawberry cultivars could be increased by polythene reflective mulches. After adjusting crop yields and cultivation using polythene mulches with two different PAR reflective capacities, field- and polytunnel-grown strawberries were analysed for ellagic acid and ascorbic acid concentrations by HPLC. Comparative measurements of yield and fruit quality were determined along with plant developmental changes. Ellagic acid concentration varied widely with strawberry cultivar (60-341 microg g(-1) frozen weight), as did the ratio of conjugated ellagic acid : free ellagic acid. Also, there was significant year-to-year variation in total ellagic acid concentration with some cultivars. Mulches with different reflective capacities impacted on strawberry production; highly reflective mulches significantly increased growth and yield, the latter due to increases in fruit size and number. Highly reflective mulches significantly increased total concentrations of ellagic acid and ascorbic acid relative to control in fruit of different cultivars. The potential of agronomic practices to enhance the concentration and amounts of these important dietary bioactive compounds is discussed.

  10. Amino Acid Composition of an Organic Brown Rice Protein Concentrate and Isolate Compared to Soy and Whey Concentrates and Isolates.

    PubMed

    Kalman, Douglas S

    2014-06-30

    A protein concentrate (Oryzatein-80™) and a protein isolate (Oryzatein-90™) from organic whole-grain brown rice were analyzed for their amino acid composition. Two samples from different batches of Oryzatein-90™ and one sample of Oryzatein-80™ were provided by Axiom Foods (Los Angeles, CA, USA). Preparation and analysis was carried out by Covance Laboratories (Madison, WI, USA). After hydrolysis in 6-N hydrochloric acid for 24 h at approximately 110 °C and further chemical stabilization, samples were analyzed by HPLC after pre-injection derivitization. Total amino acid content of both the isolate and the concentrate was approximately 78% by weight with 36% essential amino acids and 18% branched-chain amino acids. These results are similar to the profiles of raw and cooked brown rice except in the case of glutamic acid which was 3% lower in the isolate and concentrate. The amino acid content and profile of the Oryzatein-90™ isolate was similar to published values for soy protein isolate but the total, essential, and branched-chain amino acid content of whey protein isolate was 20%, 39% and 33% greater, respectively, than that of Oryzatein-90™. These results provide a valuable addition to the nutrient database of protein isolates and concentrates from cereal grains.

  11. Amino Acid Composition of an Organic Brown Rice Protein Concentrate and Isolate Compared to Soy and Whey Concentrates and Isolates

    PubMed Central

    Kalman, Douglas S.

    2014-01-01

    A protein concentrate (Oryzatein-80™) and a protein isolate (Oryzatein-90™) from organic whole-grain brown rice were analyzed for their amino acid composition. Two samples from different batches of Oryzatein-90™ and one sample of Oryzatein-80™ were provided by Axiom Foods (Los Angeles, CA, USA). Preparation and analysis was carried out by Covance Laboratories (Madison, WI, USA). After hydrolysis in 6-N hydrochloric acid for 24 h at approximately 110 °C and further chemical stabilization, samples were analyzed by HPLC after pre-injection derivitization. Total amino acid content of both the isolate and the concentrate was approximately 78% by weight with 36% essential amino acids and 18% branched-chain amino acids. These results are similar to the profiles of raw and cooked brown rice except in the case of glutamic acid which was 3% lower in the isolate and concentrate. The amino acid content and profile of the Oryzatein-90™ isolate was similar to published values for soy protein isolate but the total, essential, and branched-chain amino acid content of whey protein isolate was 20%, 39% and 33% greater, respectively, than that of Oryzatein-90™. These results provide a valuable addition to the nutrient database of protein isolates and concentrates from cereal grains. PMID:28234326

  12. Synergism and Physicochemical Properties of Anionic/Amphoteric Surfactant Mixtures with Nonionic Surfactant of Amine Oxide Type

    NASA Astrophysics Data System (ADS)

    Blagojević, S. M.; Pejić, N. D.; Blagojević, S. N.

    2017-12-01

    The physicochemical properties of initial formulation, that is anionic/amphoteric surfactants mixture SLES/AOS/CAB (sodium lauryl ether sulfate (SLES), α-olefin sulfonates (AOS) and cocamidopropyl betaine (CAB) at ratio 80 : 15 : 5) with nonionic surfactant of amine oxide type (lauramine oxide (AO)) in various concentration (1-5%) were studied. To characterize the surfactants mixture, the critical micelle concentration (CMC), surface tension (γ), foam volume, biodegradability and irritability were determined. This study showed that adding of AO in those mixtures lowered both γ and CMC as well as enhanced SLES/AOS/CAB foaming properties, but did not significantly affect biodegradability and irritability of initial formulation. Moreover, an increase in AO concentration has a meaningful synergistic effect on the initial formulation properties. All those results indicates that a nonionic surfactant of amine oxide type significantly improves the performance of anionic/amphoteric mixed micelle systems, and because of that anionic/amphoteric/nonionic mixture can be used in considerably lower concentrations as a cleaning formulation.

  13. Wolframite Conversion in Treating a Mixed Wolframite-Scheelite Concentrate by Sulfuric Acid

    NASA Astrophysics Data System (ADS)

    Shen, Leiting; Li, Xiaobin; Zhou, Qiusheng; Peng, Zhihong; Liu, Guihua; Qi, Tiangui; Taskinen, Pekka

    2017-12-01

    Complete wolframite conversion in sulfuric acid is significant for expanding the applicability of the sulfuric acid method for producing ammonium paratungstate. In this paper, the conversion of wolframite in treating a mixed wolframite-scheelite concentrate by sulfuric acid was studied systematically. The results show that the conversion of wolframite in sulfuric acid is more difficult than that of scheelite, requiring rigorous reaction conditions. A solid H2WO4 layer forms on the surfaces of the wolframite particles and becomes denser with increasing H2SO4 concentration, thus hindering the conversion. Furthermore, the difficulty in wolframite conversion can be mainly attributed to the accumulation of Fe2+ (and/or Mn2+) in the H2SO4 solution, which can be solved by reducing Fe2+ (and/or Mn2+) concentration through oxidization and/or a two-stage process. Additionally, the solid converted product of the mixed wolframite-scheelite concentrate has an excellent leachability of tungsten in an aqueous ammonium carbonate solution at ambient temperature, with approximately 99% WO3 recovery. This work presents a route for manufacturing ammonium paratungstate by treating the mixed concentrate in sulfuric acid followed by leaching in ammonium carbonate solution.

  14. Wolframite Conversion in Treating a Mixed Wolframite-Scheelite Concentrate by Sulfuric Acid

    NASA Astrophysics Data System (ADS)

    Shen, Leiting; Li, Xiaobin; Zhou, Qiusheng; Peng, Zhihong; Liu, Guihua; Qi, Tiangui; Taskinen, Pekka

    2018-02-01

    Complete wolframite conversion in sulfuric acid is significant for expanding the applicability of the sulfuric acid method for producing ammonium paratungstate. In this paper, the conversion of wolframite in treating a mixed wolframite-scheelite concentrate by sulfuric acid was studied systematically. The results show that the conversion of wolframite in sulfuric acid is more difficult than that of scheelite, requiring rigorous reaction conditions. A solid H2WO4 layer forms on the surfaces of the wolframite particles and becomes denser with increasing H2SO4 concentration, thus hindering the conversion. Furthermore, the difficulty in wolframite conversion can be mainly attributed to the accumulation of Fe2+ (and/or Mn2+) in the H2SO4 solution, which can be solved by reducing Fe2+ (and/or Mn2+) concentration through oxidization and/or a two-stage process. Additionally, the solid converted product of the mixed wolframite-scheelite concentrate has an excellent leachability of tungsten in an aqueous ammonium carbonate solution at ambient temperature, with approximately 99% WO3 recovery. This work presents a route for manufacturing ammonium paratungstate by treating the mixed concentrate in sulfuric acid followed by leaching in ammonium carbonate solution.

  15. Determining gold in water by anion-exchange batch extraction

    USGS Publications Warehouse

    McHugh, J.B.

    1986-01-01

    This paper describes a batch procedure for determining gold in natural waters. It is completely adaptable to field operations. The water samples are filtered and acidified before they are equilibrated with an anion-exchange resin by shaking. The gold is then eluted with acetone-nitric acid solution, and the eluate evaporated to dryness. The residue is taken up in hydrobromic acid-bromine solution and the gold is extracted with methyl isobutyl ketone. The extract is electrothermally atomized in an atomic-absorption spectrophotometer. The limit of determination is 1 ng 1. ?? 1986.

  16. Process for the preparation of lactic acid and glyceric acid

    DOEpatents

    Jackson, James E [Haslett, MI; Miller, Dennis J [Okemos, MI; Marincean, Simona [Dewitt, MI

    2008-12-02

    Hexose and pentose monosaccharides are degraded to lactic acid and glyceric acid in an aqueous solution in the presence of an excess of a strongly anionic exchange resin, such as AMBERLITE IRN78 and AMBERLITE IRA400. The glyceric acid and lactic acid can be separated from the aqueous solution. Lactic acid and glyceric acid are staple articles of commerce.

  17. Preparation of a Highly Fluorophilic Phosphonium Salt and its Use in a Fluorous Anion-Exchanger Membrane with High Selectivity for Perfluorinated Acids

    PubMed Central

    Boswell, Paul G.; Anfang, Alyce C.; Bühlmann, Philippe

    2008-01-01

    Fluorous solvents are the most nonpolar, nonpolarizable phases known, whereas ions are inherently polar. This makes it difficult to create salts that are soluble in a fluorous solvent. Here we present the synthesis and characterization of a new fluorophilic phosphonium salt, tris{3,5-bis[(perfluorooctyl)propyl]phenyl}methylphosphonium methyl sulfate. The salt has a solubility of at least 14 mM in perfluoro(perhydrophenanthrene), perfluoro(methylcyclohexane), and perfluorohexanes. It also shows immediate potential for use as a phase-transfer catalyst in fluorous biphasic catalysis, but in this work it is used as an anion exchanger site in the first potentiometric fluorous-membrane anion-selective electrode. The membrane sensor exhibited the exceptional selectivity of 3.9 × 1010 to 1 for perfluorooctanesulfonate over chloride, and of 2.5 × 107 to 1 for perfluorooctanoate over chloride. With improvements to the sensor’s detection limit and lifetime, it has the potential to be an attractive alternative to the expensive, time-consuming methods currently employed for measurement of perfluorinated acids. PMID:22072222

  18. Therapeutic plasma concentrations of epsilon aminocaproic acid and tranexamic acid in horses.

    PubMed

    Fletcher, D J; Brainard, B M; Epstein, K; Radcliffe, R; Divers, T

    2013-01-01

    Antifibrinolytic drugs such as epsilon aminocaproic acid (EACA) and tranexamic acid (TEA) are used to treat various bleeding disorders in horses. Although horses are hypofibrinolytic compared to humans, dosing schemes have been derived from pharmacokinetic studies targeting plasma concentrations in humans. We hypothesized therapeutic plasma concentrations of antifibrinolytic drugs in horses would be significantly lower than in humans. Our objective was to use thromboleastography (TEG) and an in vitro model of hyperfibrinolysis to predict therapeutic concentrations of EACA and TEA in horses and humans. Citrated plasma collected from 24 random source clinically healthy research horses. Commercial pooled human citrated plasma with normal coagulation parameters was purchased. Minimum tissue plasminogen activator (tPA) concentration to induce complete fibrinolysis within 10 minutes was determined using serial dilutions of tPA in equine plasma. Results used to create an in vitro hyperfibrinolysis model with equine and human citrated plasma, and the minimum concentrations of EACA and TEA required to completely inhibit fibrinolysis for 30 minutes (estimated therapeutic concentrations) determined using serial dilutions of the drugs. Estimated therapeutic concentrations of EACA and TEA were significantly lower in horses (5.82; 95% CI 3.77-7.86 μg/mL and 0.512; 95% CI 0.277-0.748 μg/mL) than in humans (113.2; 95% CI 95.8-130.6 μg/mL and 11.4; 95% CI 8.62-14.1 μg/mL). Current dosing schemes for EACA and TEA in horses may be as much as 20× higher than necessary, potentially increasing cost of treatment and risk of adverse effects. Copyright © 2013 by the American College of Veterinary Internal Medicine.

  19. Detection of anions by normal Raman spectroscopy and surface-enhanced Raman spectroscopy of cationic-coated substrates.

    PubMed

    Mosier-Boss, P A; Lieberman, S H

    2003-09-01

    The use of normal Raman spectroscopy and surface-enhanced Raman spectroscopy (SERS) of cationic-coated silver and gold substrates to detect polyatomic anions in aqueous environments is examined. For normal Raman spectroscopy, using near-infrared excitation, linear concentration responses were observed. Detection limits varied from 84 ppm for perchlorate to 2600 ppm for phosphate. In general, detection limits in the ppb to ppm concentration range for the polyatomic anions were achieved using cationic-coated SERS substrates. Adsorption of the polyatomic anions on the cationic-coated SERS substrates was described by a Frumkin isotherm. The SERS technique could not be used to detect dichromate, as this anion reacted with the coatings to form thiol esters. A competitive complexation method was used to evaluate the interaction of chloride ion with the cationic coatings. Hydrogen bonding and pi-pi interactions play significant roles in the selectivity of the cationic coatings.

  20. Physicochemical treatments of anionic surfactants wastewater: Effect on aerobic biodegradability.

    PubMed

    Aloui, Fathi; Kchaou, Sonia; Sayadi, Sami

    2009-05-15

    The effect of different physicochemical treatments on the aerobic biodegradability of an industrial wastewater resulting from a cosmetic industry has been investigated. This industrial wastewater contains 11423 and 3148mgL(-1) of chemical oxygen demand (COD) and anionic surfactants, respectively. The concentration of COD and anionic surfactants were followed throughout the diverse physicochemical treatments and biodegradation experiments. Different pretreatments of this industrial wastewater using chemical flocculation process with lime and aluminium sulphate (alum), and also advanced oxidation process (electro-coagulation (Fe and Al) and electro-Fenton) led to important COD and anionic surfactants removals. The best results were obtained using electro-Fenton process, exceeding 98 and 80% of anionic surfactants and COD removals, respectively. The biological treatment by an isolated strain Citrobacter braakii of the surfactant wastewater, as well as the pretreated wastewater by the various physicochemical processes used in this study showed that the best results were obtained with electro-Fenton pretreated wastewater. The characterization of the treated surfactant wastewater by the integrated process (electro-coagulation or electro-Fenton)-biological showed that it respects Tunisian discharge standards.

  1. The use of elements of the Stewart model (Strong Ion Approach) for the diagnostics of respiratory acidosis on the basis of the calculation of a value of a modified anion gap (AGm) in brachycephalic dogs.

    PubMed

    Sławuta, P; Glińska-Suchocka, K; Cekiera, A

    2015-01-01

    Apart from the HH equation, the acid-base balance of an organism is also described by the Stewart model, which assumes that the proper insight into the ABB of the organism is given by an analysis of: pCO2, the difference of concentrations of strong cations and anions in the blood serum - SID, and the total concentration of nonvolatile weak acids - Acid total. The notion of an anion gap (AG), or the apparent lack of ions, is closely related to the acid-base balance described according to the HH equation. Its value mainly consists of negatively charged proteins, phosphates, and sulphates in blood. In the human medicine, a modified anion gap is used, which, including the concentration of the protein buffer of blood, is, in fact, the combination of the apparent lack of ions derived from the classic model and the Stewart model. In brachycephalic dogs, respiratory acidosis often occurs, which is caused by an overgrowth of the soft palate, making it impossible for a free air flow and causing an increase in pCO2--carbonic acid anhydride The aim of the present paper was an attempt to answer the question whether, in the case of systemic respiratory acidosis, changes in the concentration of buffering ions can also be seen. The study was carried out on 60 adult dogs of boxer breed in which, on the basis of the results of endoscopic examination, a strong overgrowth of the soft palate requiring a surgical correction was found. For each dog, the value of the anion gap before and after the palate correction procedure was calculated according to the following equation: AG = ([Na+ mmol/l] + [K+ mmol/l])--([Cl- mmol/l]+ [HCO3- mmol/l]) as well as the value of the modified AG--according to the following equation: AGm = calculated AG + 2.5 x (albumins(r)--albumins(d)). The values of AG calculated for the dogs before and after the procedure fell within the limits of the reference values and did not differ significantly whereas the values of AGm calculated for the dogs before and after

  2. Age dependence of plasma phospholipid fatty acid levels: potential role of linoleic acid in the age-associated increase in docosahexaenoic acid and eicosapentaenoic acid concentrations.

    PubMed

    de Groot, Renate H M; van Boxtel, Martin P J; Schiepers, Olga J G; Hornstra, Gerard; Jolles, Jelle

    2009-10-01

    Limited information is available with respect to the association between age and the plasma phospholipid fatty acid profile. Therefore we investigated the association between plasma phospholipid fatty acid status and age after correction for sex, smoking, alcohol use, BMI and fish intake. Plasma phospholipid fatty acid composition was measured and information on fish intake and other potential covariates was collected in 234 participants of the Maastricht Aging Study. The participants were healthy individuals of both sexes with an age range between 36 and 88 years. Hierarchical linear regression analyses were applied to study the relationship between age and fatty acid concentrations. After correction for fish consumption and other relevant covariates, a significant positive relationship was observed between age of the subjects and their plasma phospholipid concentrations of DHA (22 : 6n-3, P = 0.006) and EPA (20 : 5n-3; P = 0.001). Age contributed 2.3 and 3.9 % to the amount of explained variance, respectively. The higher n-3 long-chain PUFA status at advanced age was confirmed by lower concentrations of their putative 'shortage marker' Osbond acid (ObA, 22 : 5n-6; P = 0.022 for the relationship with age after correction for covariates and fish intake, R2 0.022). Concentrations of linoleic acid (LA; 18 : 2n-6) were negatively associated with age (P < 0.001; R2 0.061). In conclusion, DHA and EPA concentrations appeared to be higher in older age groups, partly because of a higher fish intake and partly because of another age-associated mechanism, possibly involving the well-known competition with LA.

  3. Calcium and protons affect the interaction of neurotransmitters and anesthetics with anionic lipid membranes.

    PubMed

    Pérez-Isidoro, Rosendo; Ruiz-Suárez, J C

    2016-09-01

    We study how zwitterionic and anionic biomembrane models interact with neurotransmitters (NTs) and anesthetics (ATs) in the presence of Ca(2+) and different pH conditions. As NTs we used acetylcholine (ACh), γ-aminobutyric acid (GABA), and l-glutamic acid (LGlu). As ATs, tetracaine (TC), and pentobarbital (PB) were employed. By using differential scanning calorimetry (DSC), we analyzed the changes such molecules produce in the thermal properties of the membranes. We found that calcium and pH play important roles in the interactions of NTs and ATs with the anionic lipid membranes. Changes in pH promote deprotonation of the phosphate groups in anionic phospholipids inducing electrostatic interactions between them and NTs; but if Ca(2+) ions are in the system, these act as bridges. Such interactions impact the physical properties of the membranes in a similar manner that anesthetics do. Beyond the usual biochemical approach, we claim that these effects should be taken into account to understand the excitatory-inhibitory orchestrated balance in the nervous system. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Plasma amino acid concentrations in 36 dogs with histologically confirmed superficial necrolytic dermatitis.

    PubMed

    Outerbridge, Catherine A; Marks, Stanley L; Rogers, Quinton R

    2002-08-01

    Plasma amino acid concentrations were measured in 36 dogs diagnosed with superficial necrolytic dermatitis (SND) via skin biopsy. The median age of the dogs was 10 years, and 27 out of 36 (75%) were male. Twenty-two out of 36 (61%) of the dogs were accounted for by six breeds; West Highland white terriers (six), Shetland sheepdogs (five), cocker spaniels (four), Scottish terriers (three), Lhasa apsos (two) and Border collies (two). The mean concentration (+/- standard deviation) was calculated for each measured plasma amino acid and compared to previously documented concentrations of plasma amino acids measured in dogs with acute and chronic hepatitis. The ratio of branched chain amino acids to aromatic amino acids in the dogs with SND was 2.6, slightly lower than that in normal dogs. The mean plasma amino acid concentrations for dogs with SND were significantly lower than for dogs with acute and chronic hepatitis. A metabolic hepatopathy in which there is increased hepatic catabolism of amino acids is hypothesized to explain the hypoaminoacidaemia seen in SND.

  5. Sublethal detergent concentrations increase metabolization of recalcitrant polyphosphonates by the cyanobacterium Spirulina platensis.

    PubMed

    Forlani, Giuseppe; Bertazzini, Michele; Giberti, Samuele; Wieczorek, Dorota; Kafarski, Paweł; Lipok, Jacek

    2013-05-01

    As a consequence of increasing industrial applications, thousand tons of polyphosphonates are introduced every year into the environment. The inherent stability of the C-P bond results in a prolonged half-life. Moreover, low uptake rates limit further their microbial metabolization. To assess whether low detergent concentrations were able to increase polyphosphonate utilization by the cyanobacterium Spirulina platensis, tolerance limits to the exposure to various detergents were determined by measuring the growth rate in the presence of graded levels below the critical micellar concentration. Then, the amount of hexamethylenediamine-N,N,N',N'-tetrakis(methylphosphonic acid) that is metabolized in the absence or in the presence of sublethal detergent concentrations was quantified by (31)P NMR analysis on either P-starved or P-fed cyanobacterial cultures. The strain tolerated the presence of detergents in the order: nonionic > anionic > cationic. When added to the culture medium at the highest concentrations showing no detrimental effects upon cell viability, detergents either improved or decreased polyphosphonate utilization, the anionic sodium dodecyl sulfate being the most beneficial. Metabolization was not lower in P-fed cells--a result that strengthens the possibility of using, in the future, this strain for bioremediation purposes.

  6. Effects of Hofmeister salt series on gluten network formation: Part II. Anion series.

    PubMed

    Tuhumury, H C D; Small, D M; Day, L

    2016-12-01

    Different anion salts from the Hofmeister series were used to investigate their effects on gluten network formation. The effects of these anion salts on the mixing properties of the dough and the rheological and chemical properties of gluten samples extracted from the dough with these respective salts were compared. The aim of this work was to determine how different anion salts influence the formation of the gluten structure during dough mixing. It was found that the Hofmeister anion salts affected the gluten network formation by interacting directly with specific amino acid residues that resulted in changes in gluten protein composition, specifically the percentage of the unextractable polymeric protein fractions (%UPP). These changes consequently led to remarkable differences in the mixing profiles and microstructural features of the dough, small deformation rheological properties of the gluten and a strain hardening behaviour of both dough and gluten samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Low-Temperature Reactivity of C2n+1N(-) Anions with Polar Molecules.

    PubMed

    Joalland, Baptiste; Jamal-Eddine, Nour; Kłos, Jacek; Lique, François; Trolez, Yann; Guillemin, Jean-Claude; Carles, Sophie; Biennier, Ludovic

    2016-08-04

    Following the recent discovery of molecular anions in the interstellar medium, we report on the kinetics of proton transfer reactions between cyanopolyynide anions C2n+1N(-) (n = 0, 1, 2) and formic acid HCOOH. The results, obtained from room temperature down to 36 K by means of uniform supersonic flows, show a surprisingly weak temperature dependence of the CN(-) reaction rate, in contrast with longer chain anions. The CN(-) + HCOOH reaction is further studied theoretically via a reduced dimensional quantum model that highlights a tendency of the reaction probability to decrease with temperature, in agreement with experimental data but at the opposite of conventional long-range capture theories. In return, comparing HCOOH to HC3N as target molecules suggests that dipole-dipole interactions must play an active role in overcoming this limiting effect at low temperatures. This work provides new fundamental insights on prototypical reactions between polar anions and polar molecules along with critical data for astrochemical modeling.

  8. GABA signalling modulates plant growth by directly regulating the activity of plant-specific anion transporters.

    PubMed

    Ramesh, Sunita A; Tyerman, Stephen D; Xu, Bo; Bose, Jayakumar; Kaur, Satwinder; Conn, Vanessa; Domingos, Patricia; Ullah, Sana; Wege, Stefanie; Shabala, Sergey; Feijó, José A; Ryan, Peter R; Gilliham, Matthew; Gillham, Matthew

    2015-07-29

    The non-protein amino acid, gamma-aminobutyric acid (GABA) rapidly accumulates in plant tissues in response to biotic and abiotic stress, and regulates plant growth. Until now it was not known whether GABA exerts its effects in plants through the regulation of carbon metabolism or via an unidentified signalling pathway. Here, we demonstrate that anion flux through plant aluminium-activated malate transporter (ALMT) proteins is activated by anions and negatively regulated by GABA. Site-directed mutagenesis of selected amino acids within ALMT proteins abolishes GABA efficacy but does not alter other transport properties. GABA modulation of ALMT activity results in altered root growth and altered root tolerance to alkaline pH, acid pH and aluminium ions. We propose that GABA exerts its multiple physiological effects in plants via ALMT, including the regulation of pollen tube and root growth, and that GABA can finally be considered a legitimate signalling molecule in both the plant and animal kingdoms.

  9. GABA signalling modulates plant growth by directly regulating the activity of plant-specific anion transporters

    PubMed Central

    Ramesh, Sunita A.; Tyerman, Stephen D.; Xu, Bo; Bose, Jayakumar; Kaur, Satwinder; Conn, Vanessa; Domingos, Patricia; Ullah, Sana; Wege, Stefanie; Shabala, Sergey; Feijó, José A.; Ryan, Peter R.; Gillham, Matthew

    2015-01-01

    The non-protein amino acid, gamma-aminobutyric acid (GABA) rapidly accumulates in plant tissues in response to biotic and abiotic stress, and regulates plant growth. Until now it was not known whether GABA exerts its effects in plants through the regulation of carbon metabolism or via an unidentified signalling pathway. Here, we demonstrate that anion flux through plant aluminium-activated malate transporter (ALMT) proteins is activated by anions and negatively regulated by GABA. Site-directed mutagenesis of selected amino acids within ALMT proteins abolishes GABA efficacy but does not alter other transport properties. GABA modulation of ALMT activity results in altered root growth and altered root tolerance to alkaline pH, acid pH and aluminium ions. We propose that GABA exerts its multiple physiological effects in plants via ALMT, including the regulation of pollen tube and root growth, and that GABA can finally be considered a legitimate signalling molecule in both the plant and animal kingdoms. PMID:26219411

  10. Circadian changes in endogenous concentrations of indole-3-acetic acid, melatonin, serotonin, abscisic acid and jasmonic acid in Characeae (Chara australis Brown).

    PubMed

    Beilby, Mary J; Turi, Christina E; Baker, Teesha C; Tymm, Fiona Jm; Murch, Susan J

    2015-01-01

    Giant-celled Characeae (Chara australis Brown), grown for 4 months on 12/12 hr day/night cycle and summer/autumn temperatures, exhibited distinct concentration maxima in auxin (indole-3-acetic acid; IAA), melatonin and serotonin about 4 hr after subjective daybreak. These concentration peaks persisted after 3 day pretreatment in continuous darkness: confirming a circadian rhythm, rather than a response to "light on." The plants pretreated for 3 d in continuous light exhibited several large IAA concentration maxima throughout the 24 hr. The melatonin and serotonin concentrations decreased and were less synchronized with IAA. Chara plants grown on 9/15 hr day/night cycle for 4 months and winter/spring temperatures contained much smaller concentrations of IAA, melatonin and serotonin. The IAA concentration maxima were observed in subjective dark phase. Serotonin concentration peaks were weakly correlated with those of IAA. Melatonin concentration was low and mostly independent of circadian cycle. The "dark" IAA concentration peaks persisted in plants treated for 3 d in the dark. The plants pretreated for 3 d in the light again developed more IAA concentration peaks. In this case the concentration maxima in melatonin and serotonin became more synchronous with those in IAA. The abscisic acid (ABA) and jasmonic acid (JA) concentrations were also measured in plants on winter regime. The ABA concentration did not exhibit circadian pattern, while JA concentration peaks were out of phase with those of IAA. The data are discussed in terms of crosstalk between metabolic pathways.

  11. Real-time analysis of multiple anion mixtures in aqueous media using a single receptor.

    PubMed

    Havel, Vaclav; Yawer, Mirza Arfan; Sindelar, Vladimir

    2015-03-18

    Bambusuril-based receptors have been used in conjunction with (1)H NMR spectroscopy to recognize mixtures of inorganic anions in aqueous solutions. This was achieved by examining complexation-induced changes in the receptors' (1)H NMR fingerprints. This approach enables the simultaneous identification of up to 9 anions and the quantification of up to 5 anions using a single receptor in DMSO-d6 containing 5% D2O. Toxic perchlorate was recognized and quantified at 0.1 μM (1.8 ppb, mol mol(-1)) concentration in pure water.

  12. Orphenadrinium picrate picric acid

    PubMed Central

    Fun, Hoong-Kun; Hemamalini, Madhukar; Siddaraju, B. P.; Yathirajan, H. S.; Narayana, B.

    2010-01-01

    The asymmetric unit of the title compound N,N-dimethyl-2-[(2-methyl­phen­yl)phenyl­meth­oxy]ethanaminium picrate picric acid, C18H24NO+·C6H2N3O7 −·C6H3N3O7, contains one orphenadrinium cation, one picrate anion and one picric acid mol­ecule. In the orphenadrine cation, the two aromatic rings form a dihedral angle of 70.30 (7)°. There is an intra­molecular O—H⋯O hydrogen bond in the picric acid mol­ecule, which generates an S(6) ring motif. In the crystal structure, the orphenadrine cations, picrate anions and picric acid mol­ecules are connected by strong inter­molecular N—H⋯O hydrogen bonds, π⋯π inter­actions between the benzene rings of cations and anions [centroid–centroid distance = 3.5603 (9) Å] and weak C—H⋯O hydrogen bonds, forming a three-dimensional network. PMID:21580426

  13. Favorable Effects of Weak Acids on Negative-Ion Electrospray Ionization Mass Spectrometry

    PubMed Central

    Wu, Zengru; Gao, Wenqing; Phelps, Mitch A.; Wu, Di; Miller, Duane D.; Dalton, James T.

    2007-01-01

    Despite widespread use in pharmacokinetic, drug metabolism, and pesticide residue studies, little is known about the factors governing response during reversed-phase liquid chromatography coupled with negative-ion electrospray ionization (ESI−) mass spectrometry. We examined the effects of various mobile-phase modifiers on the ESI− response of four selective androgen receptor modulators using a postcolumn infusion system. Acetic, propionic, and butyric acid improved the ESI− responses of analytes to varying extents at low concentrations. Formic acid suppressed ionization, as did neutral salts (ammonium formate, ammonium acetate) and bases (ammonium hydroxide, triethylamine) under most conditions. Two modifiers (2,2,2-trifluoroethanol, formaldehyde) that produce anions with high gas-phase proton affinity increased ESI− responses. However, the concentrations of these modifiers required to enhance ESI− response were higher than that of acidic modifiers, which is a phenomenon likely related to their low pKa values. 2,2,2-Trifluoroethanol increased response of more hydrophobic compounds but decreased response of a more hydrophilic compound. Formaldehyde improved response of all the compounds, especially the hydrophilic compound with lower surface activity. In summary, these results suggest that an ideal ESI− modifier should provide cations that can be easily electrochemically reduced and produce anions with small molecular volume and high gas-phase proton affinity. PMID:14750883

  14. A computer program for geochemical analysis of acid-rain and other low-ionic-strength, acidic waters

    USGS Publications Warehouse

    Johnsson, P.A.; Lord, D.G.

    1987-01-01

    ARCHEM, a computer program written in FORTRAN 77, is designed primarily for use in the routine geochemical interpretation of low-ionic-strength, acidic waters. On the basis of chemical analyses of the water, and either laboratory or field determinations of pH, temperature, and dissolved oxygen, the program calculates the equilibrium distribution of major inorganic aqueous species and of inorganic aluminum complexes. The concentration of the organic anion is estimated from the dissolved organic concentration. Ionic ferrous iron is calculated from the dissolved oxygen concentration. Ionic balances and comparisons of computed with measured specific conductances are performed as checks on the analytical accuracy of chemical analyses. ARCHEM may be tailored easily to fit different sampling protocols, and may be run on multiple sample analyses. (Author 's abstract)

  15. Mechanism for odd-electron anion generation of dihydroxybenzoic acid isomers in matrix-assisted laser desorption/ionization mass spectrometry with density functional theory calculations.

    PubMed

    Yamagaki, Tohru; Takeuchi, Michika; Watanabe, Takehiro; Sugahara, Kohtaro; Takeuchi, Takae

    2016-12-30

    Proton and radical are transferred between matrices and matrix and analyte in matrix-assisted laser desorption/ionization (MALDI) and these transfers drive ionization of analytes. The odd-electron anion [M-2H] •- was generated in dihydroxybenzoic acids (DHBs) and the ion abundance of the 2,5-DHB was the highest among six DHB isomers. We were interested in the mechanism of the ion generation of the odd-electron anion. The observed [M-2H] •- and [M-3H] - ions, which were generated with the hydrogen radical removed from the phenolic hydroxyl groups (OH) in DHB isomers, were analyzed using negative-ion MALDI-MS. The enthalpy for ion generation and their stable structures were calculated using the density functional theory (DFT) calculation program Gaussian 09 with the B3LYP functional and the 6-31+G(d) basis set. The number of observed [M-2H] •- and [M-3H] - ions of the DHB isomers was dependent on the positions of the phenolic OH groups in the DHB isomers because the carboxy group interacts with the ortho OH group due to neighboring group participation, as confirmed from the stable structures of the [M-2H] •- anions calculated with the Gaussian 09 program. The DHB isomers were placed into three categories according to the number of the ions. Odd-electron anions ([M-2H] •- ) and [M-2H • -H] - ([M-3H] - ) ions were generated from DHB isomers due to removal of the hydrogen radical from the phenolic groups. The enthalpy for ion generation revealed that ion formation proceeds via a two-step pathway through the [M-M] - ion as an intermediate. © 2016 The Authors. Rapid Communications in Mass Spectrometry Published by John Wiley & Sons Ltd. © 2016 The Authors. Rapid Communications in Mass Spectrometry Published by John Wiley & Sons Ltd.

  16. Field-based evaluation of a male-specific (F+) RNA coliphage concentration method.

    PubMed

    Chandler, J C; Pérez-Méndez, A; Paar, J; Doolittle, M M; Bisha, B; Goodridge, L D

    2017-01-01

    Fecal contamination of water poses a significant risk to public health due to the potential presence of pathogens, including enteric viruses. Therefore, sensitive, reliable and easy to use methods for the concentration, detection and quantification of microorganisms associated with the safety and quality of water are needed. In this study, we performed a field evaluation of an anion exchange resin-based method to concentrate male-specific (F+) RNA coliphages (FRNA), fecal indicator organisms, from diverse environmental waters that were suspected to be contaminated with feces. In this system, FRNA coliphages are adsorbed to anion exchange resin and direct nucleic acid isolation is performed, yielding a sample amenable to real-time reverse transcriptase (RT)-PCR detection. Matrix-dependent inhibition of this method was evaluated using known quantities of spiked FRNA coliphages belonging to four genogroups (GI, GII, GII and GIV). RT-PCR-based detection was successful in 97%, 72%, 85% and 98% of the samples spiked (10 6 pfu/l) with GI, GII, GIII and GIV, respectively. Differential FRNA coliphage genogroup detection was linked to inhibitors that altered RT-PCR assay efficiency. No association between inhibition and the physicochemical properties of the water samples was apparent. Additionally, the anion exchange resin method facilitated detection of naturally present FRNA coliphages in 40 of 65 environmental water samples (61.5%), demonstrating the viability of this system to concentrate FRNA coliphages from water. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Anion transport and supramolecular medicinal chemistry

    DOE PAGES

    Gale, Philip A.; Davis, Jeffery T.; Quesada, Roberto

    2017-04-05

    New approaches to the transmembrane transport of anions are discussed in this review. Advances in the design of small molecule anion carriers are reviewed in addition to advances in the design of synthetic anion channels. The application of anion transporters to the potential future treatment of disease is discussed in the context of recent findings on the selectivity of anion transporters.

  18. Anion transport and supramolecular medicinal chemistry

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

    Gale, Philip A.; Davis, Jeffery T.; Quesada, Roberto

    New approaches to the transmembrane transport of anions are discussed in this review. Advances in the design of small molecule anion carriers are reviewed in addition to advances in the design of synthetic anion channels. The application of anion transporters to the potential future treatment of disease is discussed in the context of recent findings on the selectivity of anion transporters.

  19. Detoxification of Organosolv-Pretreated Pine Prehydrolysates with Anion Resin and Cysteine for Butanol Fermentation.

    PubMed

    Li, Jing; Shi, Suan; Tu, Maobing; Via, Brain; Sun, Fubao Fuelbio; Adhikari, Sushil

    2018-05-02

    Bioconversion of lignocellulose to biofuels suffers from the degradation compounds formed during pretreatment and acid hydrolysis. In order to achieve an efficient biomass to biofuel conversion, detoxification is often required before enzymatic hydrolysis and microbial fermentation. Prehydrolysates from ethanol organosolv-pretreated pine wood were used as substrates in butanol fermentation in this study. Six detoxification approaches were studied and compared, including overliming, anion exchange resin, nonionic resin, laccase, activated carbon, and cysteine. It was observed that detoxification by anion exchange resin was the most effective method. The final butanol yield after anion exchange resin treatment was comparable to the control group, but the fermentation was delayed for 72 h. The addition of Ca(OH) 2 was found to alleviate this delay and improve the fermentation efficiency. The combination of Ca(OH) 2 and anion exchange resin resulted in completion of fermentation within 72 h and acetone-butanol-ethanol (ABE) production of 11.11 g/L, corresponding to a yield of 0.21 g/g sugar. The cysteine detoxification also resulted in good detoxification performance, but promoted fermentation towards acid production (8.90 g/L). The effect of salt on ABE fermentation was assessed and the possible role of Ca(OH) 2 was to remove the salts in the prehydrolysates by precipitation.

  20. Inhibitory effects of cardols and related compounds on superoxide anion generation by xanthine oxidase.

    PubMed

    Masuoka, Noriyoshi; Nihei, Ken-ichi; Maeta, Ayami; Yamagiwa, Yoshiro; Kubo, Isao

    2015-01-01

    5-Pentadecatrienylresorcinol, isolated from cashew nuts and commonly known as cardol (C₁₅:₃), prevented the generation of superoxide radicals catalysed by xanthine oxidase without the inhibition of uric acid formation. The inhibition kinetics did not follow the Michelis-Menten equation, but instead followed the Hill equation. Cardol (C₁₀:₀) also inhibited superoxide anion generation, but resorcinol and cardol (C₅:₀) did not inhibit superoxide anion generation. The related compounds 3,5-dihydroxyphenyl alkanoates and alkyl 2,4-dihydroxybenzoates, had more than a C9 chain, cooperatively inhibited but alkyl 3,5-dihydroxybenzoates, regardless of their alkyl chain length, did not inhibit the superoxide anion generation. These results suggested that specific inhibitors for superoxide anion generation catalysed by xanthine oxidase consisted of an electron-rich resorcinol group and an alkyl chain having longer than C9 chain. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Effects of various antipsychotic drugs upon the striatal concentrations of para-hydroxyphenylacetic acid and meta-hydroxyphenylacetic acid in the mouse.

    PubMed Central

    Juorio, A. V.; McQuade, P. S.

    1983-01-01

    The endogenous concentrations of p- and m-hydroxyphenylacetic acid in the mouse caudate nucleus were determined by a gas chromatographic or a gas chromatographic-mass spectrometric technique and the concentrations were about 30 and 11 ng g-1 respectively. The subcutaneous administration of (+)-butaclamol (1 mg kg-1), haloperidol (5 mg kg-1), molindone (100 mg kg-1), sulpiride (50 mg kg-1) or chlorpromazine (20 mg kg-1) increased the concentration of mouse striatal p- and m-hydroxyphenylacetic acid; the effects were observed at 2 h after drug administration. Lower doses of chlorpromazine (2 mg kg-1), haloperidol (0.2 mg kg-1) and molindone (2 mg kg-1) did not affect p- or m-hydroxyphenylacetic acid concentrations. The time course for the concentration changes produced by chlorpromazine (20 mg kg-1) revealed that the formation of the metabolites occurred within 30 min after its administration and that their efflux from the caudate nucleus took at least 4 h for p-hydroxyphenylacetic acid and more than 8 h for m-hydroxyphenylacetic acid. Promethazine and (-)-butaclamol which have chemical structures related to chlorpromazine or (+)-butaclamol respectively but which lack antipsychotic activity, produced no effect on striatal p- or m-hydroxyphenylacetic acid concentrations. The results suggest that antipsychotic drugs increase the utilization of mouse striatal p- and m-tyramine and that after use the amines are metabolized by monoamine oxidase to form p- or m-hydroxyphenylacetic acid. The synthesis of the acid metabolites occurs within 30 min after chlorpromazine administration and their efflux from the caudate nucleus takes from 4-8 h. PMID:6196070

  2. 5-Oxoproline as a cause of high anion gap metabolic acidosis: an uncommon cause with common risk factors.

    PubMed

    Kortmann, W; van Agtmael, M A; van Diessen, J; Kanen, B L J; Jakobs, C; Nanayakkara, P W B

    2008-09-01

    High anion gap metabolic acidosis might be caused by 5-oxoproline (pyroglutamic acid). As it is very easy to treat, it might be worth drawing attention to this uncommon and probably often overlooked diagnosis. We present three cases of high anion gap metabolic acidosis due to 5-oxoproline seen within a period of six months.

  3. Use of anionic clays for photoprotection and sunscreen photostability: Hydrotalcites and phenylbenzimidazole sulfonic acid

    NASA Astrophysics Data System (ADS)

    Perioli, Luana; Ambrogi, Valeria; Rossi, Carlo; Latterini, Loredana; Nocchetti, Morena; Costantino, Umberto

    2006-05-01

    Layered double hydroxides of hydrotalcite (HTlc) type have many applications as matrices in pharmaceutical and cosmetic fields when intercalated with active species in anionic form. The aim of this work was to intercalate 2-phenyl-1H-benzimidazole-5-sulfonic acid (Eusolex 232) (EUS) as sunscreen molecule into hydrotalcites in order to obtain the sunscreen stabilization, the reduction of its photodegradation and the elimination of close contact between skin and filter. Hydrotalcites MgAl and ZnAl were used as hosts and the intercalation products obtained were characterized by TG, RX and DSC. They were also submitted to spectrophotometric assays in order to study the matrix influence on sunlight protection and on sunscreen photostability. These experiments showed that both MgAl and ZnAl HTlc intercalation products maintained the sunscreen properties and eusolex photodegradation was reduced. The in vitro EUS release from both formulations was almost negligible when compared with formulations containing free EUS. The EUS intercalation in HTlc and the respective formulations provided advantages in the maintenance of photoprotection efficacy, filter photostabilization and avoidance of a close contact between skin and filter, with consequent elimination of allergy problems and photocross reactions.

  4. Peripartum cardiomyopathy is associated with increased uric acid concentrations: A population based study.

    PubMed

    Sagy, Iftach; Salman, Amjad Abu; Kezerle, Louise; Erez, Offer; Yoel, Idan; Barski, Leonid

    Peri-partum cardiomyopathy (PPCM) is a clinical heart failure that usually develops during the final stage of pregnancy or the first months following delivery. High maternal serum uric acid concentrations have been previous associated with heart failure and preeclampsia. 1) To explored the clinical characteristics of PPCM patients; and 2) to determine the association between maternal serum uric acid concentrations and PPCM. This is a retrospective population based case control study. Cases and controls were matched 1:4 (for gestational age, medical history of cardiac conditions and creatinine); conditional logistic regression was used to identify clinical parameters that were associated with PPCM. The prevalence of peripartum cardiomyopathy at our institution was 1-3832 deliveries (42/160,964). In a matched multivariate analysis high maternal serum uric acid concentrations were associated with PPCM (O.R 1.336, 95% C.I 1.003-1.778). Uric acid concentrations were higher within the Non-Jewish patients and mothers of male infant with PPCM in compare to those without PPCM (p value 0.003 and 0.01 respectively). PPCM patients had increased maternal serum uric acid concentrations. This observation aligns with previous report regarding the increased uric acid concentration in women with preeclampsia and congestive heart failure, suggestive of a common underlying mechanism that mediates the myocardial damage. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Circadian changes in endogenous concentrations of indole-3-acetic acid, melatonin, serotonin, abscisic acid and jasmonic acid in Characeae (Chara australis Brown)

    PubMed Central

    Beilby, Mary J; Turi, Christina E; Baker, Teesha C; Tymm, Fiona JM; Murch, Susan J

    2015-01-01

    Giant-celled Characeae (Chara australis Brown), grown for 4 months on 12/12 hr day/night cycle and summer/autumn temperatures, exhibited distinct concentration maxima in auxin (indole-3-acetic acid; IAA), melatonin and serotonin about 4 hr after subjective daybreak. These concentration peaks persisted after 3 day pretreatment in continuous darkness: confirming a circadian rhythm, rather than a response to “light on.” The plants pretreated for 3 d in continuous light exhibited several large IAA concentration maxima throughout the 24 hr. The melatonin and serotonin concentrations decreased and were less synchronized with IAA. Chara plants grown on 9/15 hr day/night cycle for 4 months and winter/spring temperatures contained much smaller concentrations of IAA, melatonin and serotonin. The IAA concentration maxima were observed in subjective dark phase. Serotonin concentration peaks were weakly correlated with those of IAA. Melatonin concentration was low and mostly independent of circadian cycle. The “dark” IAA concentration peaks persisted in plants treated for 3 d in the dark. The plants pretreated for 3 d in the light again developed more IAA concentration peaks. In this case the concentration maxima in melatonin and serotonin became more synchronous with those in IAA. The abscisic acid (ABA) and jasmonic acid (JA) concentrations were also measured in plants on winter regime. The ABA concentration did not exhibit circadian pattern, while JA concentration peaks were out of phase with those of IAA. The data are discussed in terms of crosstalk between metabolic pathways. PMID:26382914

  6. Effect of age on the concentrations of amino acids in the plasma of healthy foals.

    PubMed

    Zicker, S C; Spensley, M S; Rogers, Q R; Willits, N H

    1991-07-01

    The concentrations of 23 amino acids in the plasma of 13 healthy foals were determined before suckling, when foals were 1 to 2 days old, 5 to 7 days old, 12 to 14 days old, and 26 to 28 days old. The ratio of the branched chain amino acids to the aromatic amino acids was also calculated at the 5 time points. Analysis of the concentrations at the 5 ages revealed a significant temporal relationship for each amino acid ranging from a polynomial order of 1 to 4 inclusively. There were significant differences between several concentrations of amino acids in plasma at specific sample times; however, no consistent patterns were revealed. The concentrations of amino acids in healthy foals were markedly different from previously determined values in adult horses. The significant differences in the concentrations of amino acids in plasma of healthy foals at the 5 ages may represent developmental aspects of amino acid metabolism or nutrition.

  7. Reactivity of the cadmium ion in concentrated phosphoric acid solutions.

    PubMed

    De Gyves, J; Gonzales, J; Louis, C; Bessiere, J

    1989-07-01

    The solvation transfer coefficients which characterize the changes of ion reactivity with phosphoric acid concentration have been calculated for cadmium from the constants of the successive chloride complexes, and for silver and diethyldithiophosphate from potentiometric measurements. They evidence the strong desolvation of the cadmium species in concentrated phosphoric acid media, causing a remarkable increase of its reactivity. They allow the results of liquid-liquid extraction, precipitation and flotation reactions to be correctly interpreted and their changes to be foreseen when the reagents are modified.

  8. Effect of temperature and concentration on benzoyl peroxide bleaching efficacy and benzoic acid levels in whey protein concentrate.

    PubMed

    Smith, T J; Gerard, P D; Drake, M A

    2015-11-01

    Much of the fluid whey produced in the United States is a by-product of Cheddar cheese manufacture and must be bleached. Benzoyl peroxide (BP) is currently 1 of only 2 legal chemical bleaching agents for fluid whey in the United States, but benzoic acid is an unavoidable by-product of BP bleaching. Benzoyl peroxide is typically a powder, but new liquid BP dispersions are available. A greater understanding of the bleaching characteristics of BP is necessary. The objective of the study was to compare norbixin destruction, residual benzoic acid, and flavor differences between liquid whey and 80% whey protein concentrates (WPC80) bleached at different temperatures with 2 different benzoyl peroxides (soluble and insoluble). Two experiments were conducted in this study. For experiment 1, 3 factors (temperature, bleach type, bleach concentration) were evaluated for norbixin destruction using a response surface model-central composite design in liquid whey. For experiment 2, norbixin concentration, residual benzoic acid, and flavor differences were explored in WPC80 from whey bleached by the 2 commercially available BP (soluble and insoluble) at 5 mg/kg. In liquid whey, soluble BP bleached more norbixin than insoluble BP, especially at lower concentrations (5 and 10 mg/kg) at both cold (4°C) and hot (50°C) temperatures. The WPC80 from liquid whey bleached with BP at 50°C had lower norbixin concentration, benzoic acid levels, cardboard flavor, and aldehyde levels than WPC80 from liquid whey bleached with BP at 4°C. Regardless of temperature, soluble BP destroyed more norbixin at lower concentrations than insoluble BP. The WPC80 from soluble-BP-bleached wheys had lower cardboard flavor and lower aldehyde levels than WPC80 from insoluble-BP-bleached whey. This study suggests that new, soluble (liquid) BP can be used at lower concentrations than insoluble BP to achieve equivalent bleaching and that less residual benzoic acid remains in WPC80 powder from liquid whey

  9. Stabilization of α-amylase by using anionic surfactant during the immobilization process

    NASA Astrophysics Data System (ADS)

    El-Batal, A. I.; Atia, K. S.; Eid, M.

    2005-10-01

    This work describes the entrapment of α-amylase into butylacrylate-acrylic acid copolymer (BuA/AAc) using γ irradiation. The effect of an anionic surfactant (AOT), the reuse efficiency, and kinetic behavior of immobilized α-amylase were studied. Covering of α-amylase with bis-(2-ethylhexyl)sulfosuccinate sodium salt (AOT) made the enzyme more stable than the uncovered form. The hydrolytic activity of the pre-coated immobilized α-amylase was increased below the critical micelle concentration (cmc) (10 mmol/L). The results showed an increase in the relative activity with increase in the degree of hydration. The pre-coated immobilized α-amylase showed a higher k/K and lower activation energy compared to the free and uncoated-immobilized preparation, respectively. The results suggest that the immobilization of α-amylase is a potentially useful approach for commercial starch hydrolysis in two-phase systems.

  10. Ionic species produced on gamma radiolysis: Studies by matrix isolation technique—I. Electronic absorption spectra of perfluorosubstituted aromatic radical anions

    NASA Astrophysics Data System (ADS)

    Shou-te, Lian C. T.; Mittal, Jai P.

    The absorption spectra of several perfluorosubstituted aromatic radical anions are compared with the corresponding perhydro compounds in which the various transitions involved have been assigned to those predicted theoretically. The electronic absorption spectra were obtained for pentafluorostyrene, pentafluorobenzaldehyde, pentafluorobenzoic acid, pentafluorobenzonitride, tetrafluorophthalic acid and pentafluoroaniline, by gamma radiolysis in 2-methyltetrahydrofuran at 77 K. A general similarity in the absorption spectra between the perfluorinated and the corresponding perhydro radical anion is observed except for a shift in the absorption band.

  11. A hybrid sorption - Spectrometric method for determination of synthetic anionic dyes in foodstuffs.

    PubMed

    Tikhomirova, Tatyana I; Ramazanova, Gyulselem R; Apyari, Vladimir V

    2017-04-15

    A sorption-spectrometric method for determination of the anionic synthetic dyes based on their sorption on silica sorbent modified with hexadecyl groups (C16) followed by measuring the diffuse reflectance spectra on the surface of the sorbent has been proposed. Adsorption of sulfonated azo dyes Tartrazine (E102), Sunset Yellow FCF (E110), Ponceau 4R (E124) reaches maximum in acidic medium (1M HCl - pH 1). For the quinophthalone type dye Quinoline Yellow (E104), the adsorption is also maximal in an acidic medium (1M HCl - pH 2). The triphenylmethane dye Fast Green FCF (E143) is absorbed in the wider area of pH (1M HCl - pH 6). Increasing concentration of the dyes in a solution led to the increase in absorption band intensity in diffuse reflectance spectra of the adsorbent, which was used for their direct determination. The proposed method was applied to the determination of dyes in beverages and pharmaceuticals. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Bowl adamanzanes--bicyclic tetraamines: syntheses and crystal structures of complexes with cobalt(III) and chelating coordinated oxo-anions.

    PubMed

    Broge, Louise; Søtofte, Inger; Jensen, Kristian; Jensen, Nicolai; Pretzmann, Ulla; Springborg, Johan

    2007-09-14

    Seven cobalt(III) complexes of the macrobicyclic tetraamine ligand [2(4).3(1)]adamanzane ([2(4).3(1)]adz) are reported along with the crystal structure of six of these complexes. The solid state and solution structures are discussed, and a detailed assignment of the NMR spectra of the sulfato complex is provided. Four of the seven complexes contain a chelate coordinating oxo-anion (sulfate, formiate, nitrate, carbonate). Equilibration of these species with the corresponding diaqua complex is generally slow. The rates of equilibration in 5 mol dm(-3) perchloric acid at 25 degrees C have been measured, yielding half lives of 20 min, 10 min and 3 h for the sulfato, formiato and carbonato species respectively. The corresponding reaction for the nitrato complex occurs with a half life of less than 3 min. The concentration acid dissociation constant for the Co([2(4).3(1)]adz)(HCO(3))(2+) ion has been measured to K(a) = 0.33 mol dm(-3) [25 degrees C, I = 2 mol dm(-3)] and K(a) = 0.15 mol dm(-3) [25 degrees C, I = 5 mol dm(-3)]. The propensity for coordination of sulfate was found to be large enough for a quantitative conversion of the carbonato complex to the sulfato complex to occur in 3 mol dm(-3) triflic acid containing a small sulfate contamination. On this basis the decarboxylation in 5 mol dm(-3) triflic acid of the corresponding cobalt(III) carbonato complex of the larger macrobicyclic tetraamine ligand [3(5)]adz was reinvestigated and found to lead to the sulfato complex as well. The difference in exchange rate of the oxo-anion ligands for the cobalt(III) complexes of the two adamanzane ligands is discussed and attributed to fundamental differences in the molecular structure where an inverted configuration of the secondary non-bridged amine groups is seen for the complexes of the larger [3(5)]adz ligand. The high affinity for chelating coordination of oxo-anions for these two cobalt(iii)-adamanzane-moieties is rationalised on basis of the N-Co-N angles. N

  13. Anion-intercalated layered double hydroxides modified test strips for detection of heavy metal ions.

    PubMed

    Wang, Nan; Sun, Jianchao; Fan, Hai; Ai, Shiyun

    2016-01-01

    In this work, a novel approach for facile and rapid detection of heavy metal ions using anion-intercalated layered double hydroxides (LDHs) modified test strips is demonstrated. By intercalating Fe(CN)6(4-) or S(2-) anions into the interlayers of LDHs on the filter paper, various heavy metal ions can be easily detected based on the color change before and after reaction between the anions and the heavy metal ions. Upon the dropping of heavy metal ions solutions to the test strips, the colors of the test strips changed instantly, which can be easily observed by naked eyes. With the decrease of the concentration, the color depth changed obviously. The lowest detection concentration can be up to 1×10(-6) mol L(-1). Due to the easily intercalation of anions into the interlayer of the LDHs on test trips, this procedure provides a general method for the construction of LDHs modified test strips for detection of heavy metal ions. The stability of the prepared test strips is investigated. Furthermore, all the results were highly reproducible. The test strips may have potential applications in environmental monitoring fields. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. ZEOLITE PERFORMANCE AS AN ANION EXCHANGER FOR ARSENIC SEQUESTRATION IN WATER

    EPA Science Inventory

    Zeolites are well known for their use in ion exchange and acid catalysis reactions. The use of zeolites in anion or ligand exchange reactions is less studied. The NH4+ form of zeolite Y (NY6, Faujasite) has been tested in this work to evaluate its performance for arsenic removal...

  15. Bipyrrole-Strapped Calix[4]pyrroles: Strong Anion Receptors That Extract the Sulfate Anion

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

    Kim, Sung Kuk; Lee, Juhoon; Williams, Neil J

    Cage-type calix[4]pyrroles 2 and 3 bearing two additional pyrrole groups on the strap have been synthesized. Compared with the parent calix[4]pyrrole (1), they were found to exhibit remarkably enhanced affinities for anions, including the sulfate anion (TBA+ salts), in organic media (CD2Cl2). This increase is ascribed to participation of the bipyrrole units in anion binding. Receptors 2 and 3 extract the hydrophilic sulfate anion (as the methyltrialkyl(C8-10)ammonium (A336+) salt)) from aqueous media into a chloroform phase with significantly improved efficiency (>10-fold relative to calix[4]pyrrole 1). These two receptors also solubilize into chloroform the otherwise insoluble sulfate salt, (TMA)2SO4 (tetramethylammonium sulfate).

  16. Protic ionic liquids based on the dimeric and oligomeric anions: [(AcO)xH(x-1)]-.

    PubMed

    Johansson, K M; Izgorodina, E I; Forsyth, M; MacFarlane, D R; Seddon, K R

    2008-05-28

    We describe a fluidity and conductivity study as a function of composition in N-methylpyrrolidine-acetic acid mixtures. The simple 1 : 1 acid-base mixture appears to form an ionic liquid, but its degree of ionicity is quite low and such liquids are better thought of as poorly dissociated mixtures of acid and base. The composition consisting of 3 moles acetic acid and 1 mole N-methylpyrrolidine is shown to form the highest ionicity mixture in this binary due to the presence of oligomeric anionic species [(AcO)(x)H(x-1)](-) stabilised by hydrogen bonds. These oligomeric species, being weaker bases than the acetate anion, shift the proton transfer equilibrium towards formation of ionic species, thus generating a higher degree of ionicity than is present at the 1 : 1 composition. A Walden plot analysis, thermogravimetric behaviour and proton NMR data, as well as ab initio calculations of the oligomeric species, all support this conclusion.

  17. Analysis of hyaluronic acid concentration in rat vocal folds during estral and gravidic puerperal cycles.

    PubMed

    Pedroso, José Eduardo de Sá; Brasil, Osíris Camponês do; Martins, João Roberto Maciel; Nader, Helena Bociane; Simões, Manuel de Jesus

    2009-01-01

    Hormone plays an important role in the larynx. Among other substances, vocal folds contain hyaluronic acid, which tissue concentration may vary according to hormone action. the objective of this study is to analyze hyaluronic acid concentration in the vocal folds during estral and gravidic-puerperal cycles. Experimental study. 40 adult rats were divided into two groups. In the first group we used 20 rats to establish the concentration of hyaluronic acid during the estral cycle and in the second group, 20 animals were submitted to the same procedure but during the gravidic-puerperal cycle. Variations in hyaluronic acid concentration was not observed during the estral cycle. In the gravidic puerperal cycle group, an increase in hyaluronic acid concentration was observed in the puerperal subgroup. Comparing the two groups of estral and gravidic-puerperal cycles, no difference was observed. In comparing all subgroups of estral and gravidic-puerperal cycles, an increase in hyaluronic acid concentration was noticed only in the puerperal phase.

  18. The discovery of slowness: low-capacity transport and slow anion channel gating by the glutamate transporter EAAT5.

    PubMed

    Gameiro, Armanda; Braams, Simona; Rauen, Thomas; Grewer, Christof

    2011-06-08

    Excitatory amino acid transporters (EAATs) control the glutamate concentration in the synaptic cleft by glial and neuronal glutamate uptake. Uphill glutamate transport is achieved by the co-/countertransport of Na(+) and other ions down their concentration gradients. Glutamate transporters also display an anion conductance that is activated by the binding of Na(+) and glutamate but is not thermodynamically coupled to the transport process. Of the five known glutamate transporter subtypes, the retina-specific subtype EAAT5 has the largest conductance relative to glutamate uptake activity. Our results suggest that EAAT5 behaves as a slow-gated anion channel with little glutamate transport activity. At steady state, EAAT5 was activated by glutamate, with a K(m)= 61 ± 11 μM. Binding of Na(+) to the empty transporter is associated with a K(m) = 229 ± 37 mM, and binding to the glutamate-bound form is associated with a K(m) = 76 ± 40 mM. Using laser-pulse photolysis of caged glutamate, we determined the pre-steady-state kinetics of the glutamate-induced anion current of EAAT5. This was characterized by two exponential components with time constants of 30 ± 1 ms and 200 ± 15 ms, which is an order of magnitude slower than those observed in other glutamate transporters. A voltage-jump analysis of the anion currents indicates that the slow activation behavior is caused by two slow, rate-limiting steps in the transport cycle, Na(+) binding to the empty transporter, and translocation of the fully loaded transporter. We propose a kinetic transport scheme that includes these two slow steps and can account for the experimentally observed data. Overall, our results suggest that EAAT5 may not act as a classical high-capacity glutamate transporter in the retina; rather, it may function as a slow-gated glutamate receptor and/or glutamate buffering system. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  19. Measurement of plasma homovanillic acid concentrations in schizophrenic patients.

    PubMed

    Kaminski, R; Powchick, P; Warne, P A; Goldstein, M; McQueeney, R T; Davidson, M

    1990-01-01

    1. Several lines of evidence suggest that abnormalities of central dopaminergic transmission may be involved in the expression of some schizophrenic symptoms. However, elucidation of the role of dopamine (DA) in schizophrenia has eluded investigative efforts partially because no accurate and easily repeatable measure of brain DA activity exists. 2. The development of a technique to measure homovanillic acid in plasma has offered the possibility of performing serial measurements of this major DA metabolite. 3. Assuming that plasma homovanillic acid (PHVA) concentrations is an index of brain DA activity, measurement of PHVA can play a role in elucidating the DA abnormality in schizophrenia. 4. Results to date suggest that plasma homovanillic acid concentrations are lower in chronic schizophrenic patients compared to normal controls, and that PHVA values correlate with schizophrenic symptom severity. 5. In addition, PHVA levels were shown to initially rise and subsequently decline during chronic neuroleptic administration in treatment responsive but not in treatment refractory schizophrenic patients.

  20. [Effect of Ce3+ on volatile fatty acid concentrations during anaerobic granular sludge digestion].

    PubMed

    Liang, Rui; Xia, Qing; Ding, Li-Li; Shi, Xiao-Lei; Zhao, Ming-Yu; Ren, Hong-Qiang

    2009-04-15

    Batch experiments were conducted to investigate the effect of Ce3+ on volatile fatty acid(VFA) concentrations by anaerobic granular sludge digestion using D-Glucose and acetic sodium as substrate in the state of stabilization and restart-up. Results show that when the concentration of Ce3+ is lower than 1 mg/L, VFA concentration decreases, which suggests the transformation of butyric acid to acetic acid and acetic acid to methane is promoted. When the concentration of Ce3+ is 1-10 mg/L, the bacterial activity decreases and decomposition of the acetic acid and butyric acid becomes more difficult compared with the control. Adding Ce3+ brings little change in the constitution of VFA: 96% of VFA is acetic acid and butyric acid, while the propionic acid accounts for less than 3%. With the acetic sodium as the sole carbon and energy source, adding 0.05 mg/L Ce3+ could accelerate acetate degradation. After being conserved for 4 months, the activity of the Ce-containing anaerobic granular sludge is higher than that of the Ce-free sludge. The present of Ce contributes to the restart-up of anaerobic reactors.

  1. Simplified production and concentration of HIV-1-based lentiviral vectors using HYPERFlask vessels and anion exchange membrane chromatography

    PubMed Central

    Kutner, Robert H; Puthli, Sharon; Marino, Michael P; Reiser, Jakob

    2009-01-01

    Background During the past twelve years, lentiviral (LV) vectors have emerged as valuable tools for transgene delivery because of their ability to transduce nondividing cells and their capacity to sustain long-term transgene expression in target cells in vitro and in vivo. However, despite significant progress, the production and concentration of high-titer, high-quality LV vector stocks is still cumbersome and costly. Methods Here we present a simplified protocol for LV vector production on a laboratory scale using HYPERFlask vessels. HYPERFlask vessels are high-yield, high-performance flasks that utilize a multilayered gas permeable growth surface for efficient gas exchange, allowing convenient production of high-titer LV vectors. For subsequent concentration of LV vector stocks produced in this way, we describe a facile protocol involving Mustang Q anion exchange membrane chromatography. Results Our results show that unconcentrated LV vector stocks with titers in excess of 108 transduction units (TU) per ml were obtained using HYPERFlasks and that these titers were higher than those produced in parallel using regular 150-cm2 tissue culture dishes. We also show that up to 500 ml of an unconcentrated LV vector stock prepared using a HYPERFlask vessel could be concentrated using a single Mustang Q Acrodisc with a membrane volume of 0.18 ml. Up to 5.3 × 1010 TU were recovered from a single HYPERFlask vessel. Conclusion The protocol described here is easy to implement and should facilitate high-titer LV vector production for preclinical studies in animal models without the need for multiple tissue culture dishes and ultracentrifugation-based concentration protocols. PMID:19220915

  2. Severe anion gap metabolic acidosis from acetaminophen use secondary to 5-oxoproline (pyroglutamic acid) accumulation.

    PubMed

    Zand, Ladan; Muriithi, Angela; Nelsen, Eric; Franco, Pablo M; Greene, Eddie L; Qian, Qi; El-Zoghby, Ziad M

    2012-12-01

    Anion gap metabolic acidosis (AGMA) is commonly encountered in medical practice. Acetaminophen-induced AGMA is, however, not widely recognized. We report 2 cases of high anion gap metabolic acidosis secondary to 5-oxoproline accumulation resulting from acetaminophen consumption: the first case caused by acute one-time ingestion of large quantities of acetaminophen and the second case caused by chronic repeated ingestion in a patient with chronic liver disease. Recognition of this entity facilitated timely diagnosis and effective treatment. Given acetaminophen is commonly used over the counter medication, increased recognition of this adverse effect is of important clinical significance.

  3. Near-monodisperse sodium polymethacrylates: characterization by linear salt gradient anion-exchange chromatography

    PubMed

    Freydank; Krasia; Tiddy; Patrickios

    2000-05-01

    A family of six near-monodisperse homopolymers of sodium methacrylate (Mn = 1100, 3200, 5500, 7200, 14100, and 21000) is characterized by linear salt gradient anion-exchange chromatography. Although the retention times depend on the initial and final salt concentrations of the gradient, they are almost independent of the molecular weight of poly(sodium methacrylate). This suggests that anion-exchange chromatography is incapable of resolving mixtures of a given polyelectrolyte to their components of various molecular weights, and it is therefore impossible to identify the polydispersity of such a sample using this method. The independence of the retention times from molecular weight is also predicted by a theory based on stoichiometric mass-action ion-exchange. Using this theory and our experimental retention times, the equilibrium anion-exchange constant and the corresponding Gibbs free energy of anion-exchange of the monomer repeat unit are calculated to be around 2.1 and -1.8 kJ/mol, respectively.

  4. Control of exogenous factors affecting plasma homovanillic acid concentration.

    PubMed

    Davidson, M; Giordani, A B; Mohs, R C; Mykytyn, V V; Platt, S; Aryan, Z S; Davis, K L

    1987-04-01

    Measurements of plasma homovanillic acid (pHVA) concentrations appear to be a valid research strategy in psychiatric disorders in which a central dopamine (DA) abnormality has been implicated. This study provides guidance about the control of some of the exogenous factors affecting pHVA concentrations. Fasting for 14 hours eliminates the dietary effects on pHVA in healthy human subjects. Changing position, walking for 30 minutes, or smoking two cigarettes has no effect on pHVA concentrations.

  5. Unprecedented concentrations of indigenous amino acids in primitive CR meteorites

    NASA Astrophysics Data System (ADS)

    Ehrenfreund, Pascale; Martins, Zita; Alexander, Conel; Orzechowska, Grazyna; Fogel, Marylin

    CR meteorites are among the most primitive meteorites. We have performed pioneering work determining the compositional characteristics of amino acids in this type of carbonaceous chondrites. We report the first measurements of amino acids in Antarctic CR meteorites, two of which show the highest amino acid concentrations ever found in a chondrite. We have analyzed the amino acid content of the Antarctic CRs EET92042, GRA95229 and GRO95577 using high performance liquid chromatography with UV fluorescence detection (HPLC-FD) and gas chromatography-mass spectrometry (GC-MS). Additionally, compound-specific carbon isotopic measurements for most of the individual amino acids from the EET92042 and GRA95229 meteorites were achieved by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). Our data show that EET92042 and GRA95229 are the most amino acid-rich chondrites ever analyzed, with total amino acid concentrations of 180 and 249 parts-per-million (ppm), respectively. GRO95577, however, is depleted in amino acids (<1 ppm). The most abundant amino acids present in the EET92042 and GRA95229 meteorites are the α-amino acids glycine, isovaline, α-aminoisobutyric acid (α-AIB), and alanine, with δ 13 C values ranging from +31.6% to +50.5%. The highly enriched carbon isotope results together with racemic enantiomeric ratios determined for most amino acids indicate that primitive organic matter was preserved in these meteorites. In addition, the relative abundances of α-AIB and β-alanine amongst Antarctic CR meteorites appear to correspond to the degree of aqueous alteration on their respective parent body. Investigating the abundances and isotopic composition of amino acids in primitive chondrites helps to understand the role of meteorites as a source of extraterrestrial prebiotic organic compounds to the early Earth.

  6. Catalytic actions of alkaline salts in reactions between 1,2,3,4-butanetetracarboxylic acid and cellulose: II. Esterification.

    PubMed

    Ji, Bolin; Tang, Peixin; Yan, Kelu; Sun, Gang

    2015-11-05

    1,2,3,4-Butanetetracarboxylic acid (BTCA) reacts with cellulose in two steps with catalysis of alkaline salts such as sodium hypophosphite: anhydride formation and esterification of anhydride with cellulose. The alkali metal ions were found effective in catalyzing formation of BTCA anhydride in a previous report. In this work, catalytic functions of the alkaline salts in the esterification reaction between BTCA anhydride and cellulose were investigated. Results revealed that acid anions play an important role in the esterification reaction by assisting removal of protons on intermediates and completion of the esterification between cellulose and BTCA. Besides, alkaline salts with lower pKa1 values of the corresponding acids are more effective ones for the reaction since addition of these salts could lead to lower pH values and higher acid anion concentrations in finishing baths. The mechanism explains the results of FTIR and wrinkle recovery angles of the fabrics cured under different temperatures and times. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. The identification of aluminium-resistance genes provides opportunities for enhancing crop production on acid soils.

    PubMed

    Ryan, P R; Tyerman, S D; Sasaki, T; Furuichi, T; Yamamoto, Y; Zhang, W H; Delhaize, E

    2011-01-01

    Acid soils restrict plant production around the world. One of the major limitations to plant growth on acid soils is the prevalence of soluble aluminium (Al(3+)) ions which can inhibit root growth at micromolar concentrations. Species that show a natural resistance to Al(3+) toxicity perform better on acid soils. Our understanding of the physiology of Al(3+) resistance in important crop plants has increased greatly over the past 20 years, largely due to the application of genetics and molecular biology. Fourteen genes from seven different species are known to contribute to Al(3+) tolerance and resistance and several additional candidates have been identified. Some of these genes account for genotypic variation within species and others do not. One mechanism of resistance which has now been identified in a range of species relies on the efflux of organic anions such as malate and citrate from roots. The genes controlling this trait are members of the ALMT and MATE families which encode membrane proteins that facilitate organic anion efflux across the plasma membrane. Identification of these and other resistance genes provides opportunities for enhancing the Al(3+) resistance of plants by marker-assisted breeding and through biotechnology. Most attempts to enhance Al(3+) resistance in plants with genetic engineering have targeted genes that are induced by Al(3+) stress or that are likely to increase organic anion efflux. In the latter case, studies have either enhanced organic anion synthesis or increased organic anion transport across the plasma membrane. Recent developments in this area are summarized and the structure-function of the TaALMT1 protein from wheat is discussed.

  8. Metal and anion composition of two biopolymeric chemical stabilizers and toxicity risk implication for the environment.

    PubMed

    Ndibewu, P P; Mgangira, M B; Cingo, N; McCrindle, R I

    2010-01-01

    The objective of this study was to (1) measure the concentration of four anions (Cl(-), F(-), [image omitted], and [image omitted]) and nine other elements (Al, Ba, Ca, K, Mg, Mn, Fe, Ni, and Si) in two nontraditional biopolymeric chemical stabilizers (EBCS1 and EBCS2), (2) investigate consequent environmental toxicity risk implications, and (3) create awareness regarding environmental health issues associated with metal concentration levels in enzyme-based chemical stabilizers that are now gaining widespread application in road construction and other concrete materials. Potential ecotoxicity impacts were studied on aqueous extracts of EBCS1 and EBCS2 using two thermodynamic properties models: the Pitzer-Mayorga model (calculation of the electrolyte activity coefficients) and the Millero-Pitzer model (calculation of the ionic activity coefficients). Results showed not only high concentrations of a variety of metal ions and inorganic anions, but also a significant variation between two chemical stabilizing mixtures. The mixture (EBCS2) with the lower pH value was richer in all the cationic and anionic species than (EBCS1). Sulfate (SO(2-)(4)) concentrations were found to be higher in EBCS2 than in EBCS1. There was no correlation between electrolyte activity and presence of the ionic species, which may be linked to a possible high ionic environmental activity. The concentrations of trace metals found (Mn, Fe, and Ni) were low compared to those of earth metals (Ba, Ca, K, and Mg). The metal concentrations were higher in EBCS1 than in EBCS2. Data suggest that specific studies are needed to establish "zero" permissible metal ecotoxicity values for elements and anions in any such strong polyelectrolytic enzyme-based chemical stabilizers.

  9. Partial molar volume of anionic polyelectrolytes in aqueous solution.

    PubMed

    Salamanca, Constain; Contreras, Martín; Gamboa, Consuelo

    2007-05-15

    In this work the partial molar volumes (V) of different anionic polyelectrolytes and hydrophobically modified polyelectrolytes (PHM) were measured. Polymers like polymaleic acid-co-styrene, polymaleic acid-co-1-olefin, polymaleic acid-co-vinyl-2-pyrrolidone, and polyacrylic acid (abbreviated as MAS-n, PA-n-K2, AMVP, and PAA, respectively) were employed. These materials were investigated by density measurements in highly dilute aqueous solutions. The molar volume results allow us to discuss the effect of the carboxylic groups and the contributions from the comonomeric principal chain. The PAA presents the smaller V, while the largest V value was for AMVP. The V of PHM shows a linear relationship with the number of methylene groups in the lateral chain. It is found that the magnitude of the contribution per methylene group decreases as the hydrophobic character of the environment increases.

  10. A macrocyclic polyamine as an anion receptor in the capillary electrochromatographic separation of carbohydrates.

    PubMed

    Liu, Chuen-Ying; Chen, Tse-Hsien; Misra, Tarun Kumar

    2007-06-22

    An analytical approach of the 32-membered macrocyclic polyamine, 1,5,9,13,17,21,25,29-octaazacyclodotriacontane ([32]ane-N8) was described for the capillary electrochromatographic (CEC) separation of derivatized mono- and disaccharides. The column displayed reversal electroosmotic flow (EOF) at pH below 7.0, while a cathodic EOF was shown at pH above 7.0. The reductive amination of saccharides was carried out with p-aminobenzoic acid. Some parameters that affect the CEC separations were investigated. Several competitive ligands, such as Tris, EDTA and phosphate were also examined for the effect on the performance. We achieved a complete separation of all compounds as well as the excess derivatizing agent by using borate buffer (pH 9.0) in a mode of concentration gradient (60 mM inlet side and 70 mM outlet side). The relative standard deviation of the retention time measured for each sample was less than 4% in six continuous runs, suggesting that the bonded phase along with the gradient formed inside the column was quite stable. With the mixing modes of anion coordination, anion exchange, and shape discrimination, the interaction adequately accomplishes the separation of carbohydrates which are epimers or have different glycosidic linkage, although the electrophoretic migration is also involved in the separation mechanism.

  11. Effects of squat exercise and branched-chain amino acid supplementation on plasma free amino acid concentrations in young women.

    PubMed

    Shimomura, Yoshiharu; Kobayashi, Hisamine; Mawatari, Kazunori; Akita, Keiichi; Inaguma, Asami; Watanabe, Satoko; Bajotto, Gustavo; Sato, Juichi

    2009-06-01

    The present study was conducted to examine alterations in plasma free amino acid concentrations induced by squat exercise and branched-chain amino acid (BCAA) supplementation in young, untrained female subjects. In the morning on the exercise session day, participants ingested drinks containing either BCAA (isoleucine:leucine:valine=1:2.3:1.2) or dextrin (placebo) at 0.1 g/kg body weight 15 min before a squat exercise session, which consisted of 7 sets of 20 squats, with 3 min intervals between sets. In the placebo trial, plasma BCAA concentrations were decreased subsequent to exercise, whereas they were significantly increased in the BCAA trial until 2 h after exercise. Marked changes in other free amino acids in response to squat exercise and BCAA supplementation were observed. In particular, plasma concentrations of methionine and aromatic amino acids were temporarily decreased in the BCAA trial, being significantly lower than those in the placebo trial. These results suggest that BCAA intake before exercise affects methionine and aromatic amino acid metabolism.

  12. Dehydrogenation of formic acid catalyzed by magnesium hydride anions, HMgL2- (L = Cl and HCO2)

    NASA Astrophysics Data System (ADS)

    Khairallah, George N.; O'Hair, Richard A. J.

    2006-08-01

    A two step gas-phase catalytic cycle for the dehydrogenation of formic acid was established using a combination of experiments carried out on a quadrupole ion trap mass spectrometer and DFT calculations. The catalysts are the magnesium hydride anions HMgL2- (L = Cl and HCO2), which are formed from the formate complexes, HCO2MgL2-, via elimination of carbon dioxide under conditions of collision induced dissociation. This is followed by an ion-molecule reaction between HMgL2- and formic acid, which yields hydrogen and also reforms the formate complex, HCO2MgL2-. A kinetic isotope effect in the range 2.3-2.9 was estimated for the rate determining decarboxylation step by carrying out CID on the (HCO2)(DCO2)MgCl2- and subjecting the resultant mixture of (H)(DCO2)MgCl2- and (HCO2)(D)MgCl2- ions at m/z 106 to ion-molecule reactions. DFT calculations (at the B3LYP/6-31 + G* level of theory) were carried out on the HMgCl2- system and revealed that: (i) the decarboxylation of HCO2MgCl2- is endothermic by 47.8 kcal mol-1, consistent with the need to carry out CID to form the HMgCl2-; (ii) HMgCl2- can react with formic acid via either a four centred transition state or a six centred transition state. The former reaction is favoured by 7.8 kcal mol-1.

  13. Highly Dynamic Anion-Quadrupole Networks in Proteins.

    PubMed

    Kapoor, Karan; Duff, Michael R; Upadhyay, Amit; Bucci, Joel C; Saxton, Arnold M; Hinde, Robert J; Howell, Elizabeth E; Baudry, Jerome

    2016-11-01

    The dynamics of anion-quadrupole (or anion-π) interactions formed between negatively charged (Asp/Glu) and aromatic (Phe) side chains are for the first time computationally characterized in RmlC (Protein Data Bank entry 1EP0 ), a homodimeric epimerase. Empirical force field-based molecular dynamics simulations predict anion-quadrupole pairs and triplets (anion-anion-π and anion-π-π) are formed by the protein during the simulated trajectory, which suggests that the anion-quadrupole interactions may provide a significant contribution to the overall stability of the protein, with an average of -1.6 kcal/mol per pair. Some anion-π interactions are predicted to form during the trajectory, extending the number of anion-quadrupole interactions beyond those predicted from crystal structure analysis. At the same time, some anion-π pairs observed in the crystal structure exhibit marginal stability. Overall, most anion-π interactions alternate between an "on" state, with significantly stabilizing energies, and an "off" state, with marginal or null stabilizing energies. The way proteins possibly compensate for transient loss of anion-quadrupole interactions is characterized in the RmlC aspartate 84-phenylalanine 112 anion-quadrupole pair observed in the crystal structure. A double-mutant cycle analysis of the thermal stability suggests a possible loss of anion-π interactions compensated by variations of hydration of the residues and formation of compensating electrostatic interactions. These results suggest that near-planar anion-quadrupole pairs can exist, sometimes transiently, which may play a role in maintaining the structural stability and function of the protein, in an otherwise very dynamic interplay of a nonbonded interaction network as well as solvent effects.

  14. The critical relation between chemical stability of cations and water in anion exchange membrane fuel cells environment

    NASA Astrophysics Data System (ADS)

    Dekel, Dario R.; Willdorf, Sapir; Ash, Uri; Amar, Michal; Pusara, Srdjan; Dhara, Shubhendu; Srebnik, Simcha; Diesendruck, Charles E.

    2018-01-01

    Anion exchange membrane fuel cells can potentially revolutionize energy storage and delivery; however, their commercial development is hampered by a significant technological impedance: the chemical decomposition of the anion exchange membranes during operation. The hydroxide anions, while transported from the cathode to the anode, attack the positively charged functional groups in the polymer membrane, neutralizing it and suppressing its anion-conducting capability. In recent years, several new quaternary ammonium salts have been proposed to address this challenge, but while they perform well in ex-situ chemical studies, their performance is very limited in real fuel cell studies. Here, we use experimental work, corroborated by molecular dynamics modeling to show that water concentration in the environment of the hydroxide anion, as well as temperature, significantly impact its reactivity. We compare different quaternary ammonium salts that have been previously studied and test their stabilities in the presence of relatively low hydroxide concentration in the presence of different amounts of solvating water molecules, as well as different temperatures. Remarkably, with the right amount of water and at low enough temperatures, even quaternary ammonium salts which are considered "unstable", present significantly improved lifetime.

  15. Screening of anionic-modified polymers in terms of stability, disintegration, and swelling behavior.

    PubMed

    Laffleur, Flavia; Ijaz, Muhammad; Menzel, Claudia

    2017-11-01

    This study aimed to screen the stability, disintegration, and swelling behavior of chemically modified anionic polymers. Investigated polymers were well-known and widely used staples of the pharmaceutical and medical field, namely, alginate (AL), carboxymethyl cellulose (CMC), polycarbophil (PC), and hyaluronic acid (HA). On the basis of amide bond formation between the carboxylic acid moieties of anionic polymers and the primary amino group of the modification ligand cysteine (CYS), the modified polymers were obtained. Unmodified polymers served as controls throughout all studies. With the Ellman's assay, modification degrees were determined of synthesized polymeric excipients. Stability assay in terms of erosion study at physiological conditions were performed. Moreover, water uptake of compressed polymeric discs were evaluated and further disintegration studies according to the USP were carried out to define the potential ranking. Results ranking figured out PCCYS > CMCCYS > HACYS > ALCYS in terms of water uptake capacity compared to respective controls. Cell viability assays on Caco-2 cell line as well as on RPMI 2650 (ATTC CCL30) proved modification not being harmful to those. Due to the results of this study, an intense screening of prominent anionic polymer derivate was performed in order to help the pharmaceutical research for the best choice of polymeric excipients for developments of controlled drug release systems.

  16. Anion-Regulated Selective Generation of Cobalt Sites in Carbon: Toward Superior Bifunctional Electrocatalysis

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

    Wan, Gang; Yang, Ce; Zhao, Wanpeng

    The introduction of active transition metal sites (TMSs) in carbon enables the synthesis of noble-metal-free electrocatalysts for clean energy conversion applications, however, there are often multiple existing forms of TMSs, which are of different natures and catalytic models. Regulating the evolution of distinctive TMSs is highly desirable but remains challenging to date. Anions, as essential elements involved in the synthesis, have been totally neglected previously in the construction of TMSs. Herein, the effects of anions on the creation of different types of TMSs is investigated for the first time. It is found that the active cobalt-nitrogen sites tend to bemore » selectively constructed on the surface of N-doped carbon by using chloride, while metallic cobalt nanoparticles encased in protective graphite layers are the dominant forms of cobalt species with nitrate ions. The obtained catalysts demonstrate cobalt-sites-dependent activity for ORR and HER in acidic media. And the remarkably enhanced catalytic activities approaching that of benchmark Pt/C in acidic medium has been obtained on the catalyst dominated with cobalt-nitrogen sites, confirmed by the advanced spectroscopic . Our finding demonstrates a general paradigm of anion-regulated evolution of distinctive TMSs, providing a new pathway for enhancing performances of various targeted reactions related with TMSs.« less

  17. On the inhibition of muscle membrane chloride conductance by aromatic carboxylic acids

    PubMed Central

    Palade, PT; Barchi, RL

    1977-01-01

    25 aromatic carboxylic acids which are analogs of benzoic acid were tested in the rat diaphragm preparation for effects on chloride conductance (G(Cl)). Of the 25, 19 were shown to reduce membrane G(Cl) with little effect on other membrane parameters, although their apparent K(i) varied widely. This inhibition was reversible if exposure times were not prolonged. The most effective analog studied was anthracene-9-COOH (9-AC; K(i) = 1.1 x 10(-5) M). Active analogs produced concentration-dependent inhibition of a type consistent with interaction at a single site or group of sites having similar binding affinities, although a correlation could also be shown between lipophilicity and K(i). Structure-activity analysis indicated that hydrophobic ring substitution usually increased inhibitory activity while para polar substitutions reduced effectiveness. These compounds do not appear to inhibit G(Cl) by altering membrane surface charge and the inhibition produced is not voltage dependent. Qualitative characteristics of the I-V relationship for Cl(-) current are not altered. Conductance to all anions is not uniformly altered by these acids as would be expected from steric occlusion of a common channel. Concentrations of 9-AC reducing G(Cl) by more than 90 percent resulted in slight augmentation of G(I). The complete conductance sequence obtained at high levels of 9-AC was the reverse of that obtained under control conditions. Permeability sequences underwent progressive changes with increasing 9-AC concentration and ultimately inverted at high levels of the analog. Aromatic carboxylic acids appear to inhibit G(Cl) by binding to a specific intramembrane site and altering the selectivity sequence of the membrane anion channel. PMID:894246

  18. The roles of organic anion permeases in aluminium resistance and mineral nutrition.

    PubMed

    Delhaize, Emmanuel; Gruber, Benjamin D; Ryan, Peter R

    2007-05-25

    Soluble aluminium (Al(3+)) is the major constraint to plant growth on acid soils. Plants have evolved mechanisms to tolerate Al(3+) and one type of mechanism relies on the efflux of organic anions that protect roots by chelating the Al(3+). Al(3+) resistance genes of several species have now been isolated and found to encode membrane proteins that facilitate organic anion efflux from roots. These proteins belong to the Al(3+)-activated malate transporter (ALMT) and multi-drug and toxin extrusion (MATE) families. We review the roles of these proteins in Al(3+) resistance as well as their roles in other aspects of mineral nutrition.

  19. Hydration of a Large Anionic Charge Distribution - Naphthalene-Water Cluster Anions

    NASA Astrophysics Data System (ADS)

    Weber, J. Mathias; Adams, Christopher L.

    2010-06-01

    We report the infrared spectra of anionic clusters of naphthalene with up to three water molecules. Comparison of the experimental infrared spectra with theoretically predicted spectra from quantum chemistry calculations allow conclusions regarding the structures of the clusters under study. The first water molecule forms two hydrogen bonds with the π electron system of the naphthalene moiety. Subsequent water ligands interact with both the naphthalene and the other water ligands to form hydrogen bonded networks, similar to other hydrated anion clusters. Naphthalene-water anion clusters illustrate how water interacts with negative charge delocalized over a large π electron system. The clusters are interesting model systems that are discussed in the context of wetting of graphene surfaces and polyaromatic hydrocarbons.

  20. Acid-base and hormonal abnormalities in dogs with naturally occurring diabetes mellitus.

    PubMed

    Durocher, Lawren L; Hinchcliff, Kenneth W; DiBartola, Stephen P; Johnson, Susan E

    2008-05-01

    To examine acid-base and hormonal abnormalities in dogs with diabetes mellitus. Cross-sectional study. 48 dogs with diabetes mellitus and 17 healthy dogs. Blood was collected and serum ketone, glucose, lactate, electrolytes, insulin, glucagon, cortisol, epinephrine, norepinephrine, nonesterified fatty acid, and triglyceride concentrations were measured. Indicators of acid-base status were calculated and compared between groups. Serum ketone and glucose concentrations were significantly higher in diabetic than in healthy dogs, but there was no difference in venous blood pH or base excess between groups. Anion gap and strong ion difference were significantly higher and strong ion gap and serum bicarbonate concentration were significantly lower in the diabetic dogs. There were significant linear relationships between measures of acid-base status and serum ketone concentration, but not between measures of acid-base status and serum lactate concentration. Serum insulin concentration did not differ significantly between groups, but diabetic dogs had a wider range of values. All diabetic dogs with a serum ketone concentration > 1,000 micromol/L had a serum insulin concentration < 5 microU/mL. There were strong relationships between serum ketone concentration and serum glucagon-insulin ratio, serum cortisol concentration, and plasma norepinephrine concentration. Serum beta-hydroxybutyrate concentration, expressed as a percentage of serum ketone concentration, decreased as serum ketone concentration increased. Results suggested that ketosis in diabetic dogs was related to the glucagon-insulin ratio with only low concentrations of insulin required to prevent ketosis. Acidosis in ketotic dogs was attributable largely to high serum ketone concentrations.

  1. Analysis of amino acids and carbohydrates in green coffee.

    PubMed

    Murkovic, Michael; Derler, Karin

    2006-11-30

    The analysis of carbohydrates and amino acids in green coffee is of the utmost importance since these two classes of compounds act as precursors of the Maillard reaction during which the colour and aroma are formed. During the course of the Maillard reaction potentially harmful substances like acrylamide or 5-hydroxymethyl-furfural accrue as well. The carbohydrates were analysed by anion-exchange chromatography with pulsed amperometric detection and the amino acids by reversed phase chromatography after derivatization with 6-amino-quinolyl-N-hydroxysuccinimidyl carbamate and fluorescence detection. Both methods had to be optimized to obtain a sufficient resolution of the analytes for identification and quantification. Sucrose is the dominant carbohydrate in green coffee with a concentration of up to 90 mg/g (mean = 73 mg/g) in arabica beans and significantly lower amounts in robusta beans (mean=45 mg/g). Alanine is the amino acid with the highest concentration (mean = 1200 microg/g) followed by asparagine (mean = 680 microg/g) in robusta and 800 microg/g and 360 microg/g in arabica respectively. In general, the concentration of amino acids is higher in robusta than in arabica.

  2. Parturient hypocalcemia in jersey cows fed alfalfa haylage-based diets with different cation to anion ratios.

    PubMed

    Gaynor, P J; Mueller, F J; Miller, J K; Ramsey, N; Goff, J P; Horst, R L

    1989-10-01

    Jersey cows were fed three alfalfa haylage-based diets with different cation-anion balances beginning 6 wk preceding third or later calving and ending 24 to 36 h postpartum. Sodium and Cl as percentages of dietary DM were .08 and 1.66 in diet 1 (anionic, 5 cows), .44 and .91 in diet 2 (intermediate, 6 cows), and 1.60 and .34 in diet 3 (cationic, 6 cows). Cation-anion balances were 22, 60, and 126 meq/100 g DM; Ca:P ratios averaged 4:1. Cows fed diet 1 in comparison with cows fed diets 2 or 3 over 6 wk had similar concentrations of Ca, P, and Na but higher concentrations of Mg and K in plasma and higher urinary excretions of Ca and Mg. Concentrations of 1,25-dihydroxyvitamin D 3 d before parturition were higher in cows fed diet 1 than in cows fed diets 2 or 3. Within 36 h after calving, mean concentrations of Ca in plasma (mg/dl, range) of cows fed diets 1 to 3, respectively, were 7 (8.7 to 6.2), 6.5 (7.8 to 3.9), and 6.3 (7.8 to 3.8). Number of cases of clinical milk fever by diet were 0 of 5, 2 of 6, and 1 of 6 cows. Alteration of dietary cation-anion balance by addition of Cl may effectively reduce incidence and severity of parturient hypocalcemia.

  3. Effect of a protein-rich meal on urinary and salivary free amino acid concentrations in human subjects.

    PubMed

    Brand, H S; Jörning, G G; Chamuleau, R A; Abraham-Inpijn, L

    1997-08-08

    The aim of the present study was to investigate whether in healthy volunteers acute changes in plasma free amino acid composition after a protein-rich test meal are reflected in the urinary and salivary concentrations of the corresponding amino acids. The ingestion of a protein-rich meal elicited a significant increase of plasma and urine amino acid concentrations. The postprandial salivary amino acid excretion showed only minor changes. For several amino acids (alanine, arginine, asparagine, glycine, threonine and valine) significant relations were observed between the increase in concentration of these amino acids in venous plasma and urine. In whole saliva, only threonine and valine showed a significant relationship with the corresponding plasma concentration. Our data suggest that the urinary amino acid excretion of several amino acids has the potential for estimating short-term changes in plasma concentrations. Determination of salivary amino acid concentrations seems less appropriate for this purpose.

  4. Statins, fibrates, nicotinic acid, cholesterol absorption inhibitors, anion-exchange resins, omega-3 fatty acids: which drugs for which patients?

    PubMed

    Drexel, Heinz

    2009-12-01

    Classes of lipid lowering drugs differ strongly with respect to the types of lipids or lipoproteins they predominantly affect. Statins inhibit the de-novo synthesis of cholesterol. Consequently, the liver produces less VLDL, and the serum concentration primarily of LDL cholesterol (but, to a lesser extent, also of triglycerides) is lowered. Further, statins somewhat increase HDL cholesterol. There is abundant evidence that statins lower the rate of cardiovascular events. Cardiovascular risk reduction is the better, the lower the LDL cholesterol values achieved with statin therapy are. Some evidence is available that anion exchange resins which also decrease LDL cholesterol decrease vascular risk, too. This is not the case for the ezetimibe, which strongly lowers LDL cholesterol: its potential to decrease vascular risk remains to be proven. In contrast evidence for cardiovascular risk reduction through the mainly triglyceride lowering fibrates as well as for niacin is available. Niacin is the most potent HDL increasing drug currently available and besides increasing HDL cholesterol efficaciously lowers triglycerides and LDL cholesterol. Large ongoing trials address the decisive question whether treatment with fibrates and niacin provides additional cardiovascular risk reduction when given in addition to statin treatment.

  5. Ruthenium(II) 2,2'-bibenzimidazole complex as a second-sphere receptor for anions interaction and colorimeter.

    PubMed

    Cui, Ying; Niu, Yan-Li; Cao, Man-Li; Wang, Ke; Mo, Hao-Jun; Zhong, Yong-Rui; Ye, Bao-Hui

    2008-07-07

    A ruthenium(II) complex [Ru(bpy) 2(H 2bbim)](PF 6) 2 ( 1) as anions receptor has been exploited, where Ru(II)-bpy moiety acts as a chromophore and the H 2bbim ligand as an anion binding site. A systematic study suggests that 1 interacts with the Cl (-), Br (-), I (-), NO 3 (-), HSO 4 (-), and H 2PO 4 (-) anions via the formation of hydrogen bonds. Whereas 1 undergoes a stepwise process with the addition of F (-) and OAc (-) anions: formation of the monodeprotonated complex [Ru(bpy) 2(Hbbim)] with a low anion concentration, followed by the double-deprotonated complex [Ru(bpy) 2(bbim)], in the presence of a high anion concentration. These stepwise processes concomitant with the changes of vivid colors from yellow to orange brown and then to violet can be used for probing the F (-) and OAc (-) anions by naked eye. The deprotonation processes are not only determined by the basicity of the anion but also related to the strength of hydrogen bonding, as well as the stability of the formed compounds. Moreover, a double-deprotonated complex [Ru(bpy) 2(bbim)].CH 3OH.H 2O ( 3) has been synthesized, and the structural changes induced by the deprotonation has also been investigated. In addition, complexes [Ru(bpy) 2(Hbbim)] 2(HOAc) 3Cl 2.12H 2O ( 2), [Ru(bpy) 2(Hbbim)](HCCl 3CO 2)(CCl 3CO 2).2H 2O ( 4), and [Ru(bpy) 2(H 2bbim)](CF 3CO 2) 2.4H 2O ( 5) have been synthesized to observe the second sphere coordination between the Ru(II)-H 2bbim moiety and carboxylate groups via hydrogen bonds in the solid state.

  6. Protein Camouflage: Supramolecular Anion Recognition by Ubiquitin.

    PubMed

    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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Time-dependent changes in the plasma amino acid concentration in diabetes mellitus.

    PubMed

    Mochida, Taiga; Tanaka, Takayuki; Shiraki, Yasuko; Tajiri, Hiroko; Matsumoto, Shirou; Shimbo, Kazutaka; Ando, Toshihiko; Nakamura, Kimitoshi; Okamoto, Masahiro; Endo, Fumio

    2011-08-01

    We investigated longitudinal change in the amino acid (AA) profile in type 1 diabetes mellitus (DM) using AKITA mice, which develop DM as a result of insulin deficiency. The plasma concentrations of valine, leucine, isoleucine, as well as the total branched chain amino acids, alanine, citrulline and proline, were significantly higher in the diabetic mice. We show that the degree and timing of the changes were different among the plasma amino acid concentrations (pAAs) during the development of type 1 DM. Copyright © 2011 Elsevier Inc. All rights reserved.

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

    ERIC Educational Resources Information Center

    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…

  9. Anionic pH-Sensitive Lipoplexes.

    PubMed

    Mignet, Nathalie; Scherman, Daniel

    2017-01-01

    To provide long circulating nanoparticles able to carry a gene to tumors, we have designed anionic pegylated lipoplexes which are pH sensitive. Anionic pegylated lipoplexes have been prepared from the combined formulation of cationic lipoplexes and pegylated anionic liposomes. The neutralization of the particle surface charge as a function of the pH was monitored by light scattering in order to determine the ratio between anionic and cationic lipids that would give pH sensitive complexes. This ratio has been optimized to form particles sensitive to pH change in the range 5.5-6.5. Compaction of DNA into these newly formed anionic complexes is checked by DNA accessibility to picogreen. The transfection efficiency and pH sensitive property of these formulations has been shown in vitro using bafilomycin, a vacuolar H + -ATPase inhibitor.

  10. Anion-π Catalysis on Fullerenes.

    PubMed

    López-Andarias, Javier; Frontera, Antonio; Matile, Stefan

    2017-09-27

    Anion-π interactions on fullerenes are about as poorly explored as the use of fullerenes in catalysis. However, strong exchange-correlation contributions and the localized π holes on their surface promise unique selectivities. To elaborate on this promise, tertiary amines are attached nearby. Dependent on their positioning, the resulting stabilization of anionic transition states on fullerenes is shown to accelerate disfavored enolate addition and exo Diels-Alder reactions enantioselectively. The found selectivities are consistent with computational simulations, particularly concerning the discrimination of differently planarized and charge-delocalized enolate tautomers by anion-π interactions. Enolate-π interactions on fullerenes are much shorter than standard π-π interactions and anion-π interactions on planar surfaces, and alternative cation-π interactions are not observed. These findings open new perspectives with regard to anion-π interactions in general and the use of carbon allotropes in catalysis.

  11. Effects of Oral Glucosamine Hydrochloride Administration on Plasma Free Amino Acid Concentrations in Dogs

    PubMed Central

    Azuma, Kazuo; Osaki, Tomohiro; Tsuka, Takeshi; Imagawa, Tomohiro; Okamoto, Yoshiharu; Takamori, Yoshimori; Minami, Saburo

    2011-01-01

    We examined the effects of oral glucosamine hydrochloride (GlcN), N-acetyl-d-glucosamine (GlcNAc) and d-glucose (Glc) administration on plasma total free amino acid (PFAA) concentrations in dogs. The PFAA concentrations increased in the control group and the GlcNAc group at one hour after feeding, and each amino acid concentration increased. On the other hand, in the GlcN group and the Glc group PFAA concentrations decreased at one hour after feeding. A significant decrease in amino acid concentration was observed for glutamate, glycine and alanine. Our results suggest the existence of differences in PFAA dynamics after oral administration of GlcN and GlcNAc in dogs. PMID:21673884

  12. On-line packed magnetic in-tube solid phase microextraction of acidic drugs such as naproxen and indomethacin by using Fe3O4@SiO2@layered double hydroxide nanoparticles with high anion exchange capacity.

    PubMed

    Shamsayei, Maryam; Yamini, Yadollah; Asiabi, Hamid; Safari, Meysam

    2018-02-22

    The authors describe a 3-component nanoparticle system composed of a silica-coated magnetite (Fe 3 O 4 ) core and a layered double (Cu-Cr) hydroxide nanoplatelet shell. The sorbent has a high anion exchange capacity for extraction anionic species. A simple online system, referred to as "on-line packed magnetic-in-tube solid phase microextraction" was designed. The nanoparticles were placed in a stainless steel cartridge via dry packing. The cartridge was then applied to the preconcentration acidic drugs including naproxen and indomethacin from urine and plasma. Extraction and desorption times, pH values of the sample solution and flow rates of sample solution and eluent were optimized. Analytes were then quantified by HPLC with UV detection. Under optimal conditions, the limits of detection range from 70 to 800 ng L -1 , with linear responses from 0.1-500 μg L -1 (water samples), 0.6-500 μg L -1 (spiked urine), and 0.9-500 μg L -1 (spiked plasma). The inter- and intra-assay precisions (RSDs, for n = 5) are in the range of 2.2-5.4%, 2.8-4.9%, and 2.0-5.2% at concentration levels of 5, 25 and 50 μg L -1 , respectively. The method was applied to the analysis of the drugs in spiked human urine and plasma, and good results were achieved. Graphical abstract Fe 3 O 4 @SiO 2 @CuCr-LDH magnetic nanoparticles were synthesized and packed in to a stainless steel column. The column was applied to solid phase microextraction of acidic drugs from biological samples.

  13. Development of anion-selective membranes. [for energy storage

    NASA Technical Reports Server (NTRS)

    Lacey, R. E.; Cowsar, D. R.

    1975-01-01

    Methods were studied of preparing anion-exchange membranes that would have low resistance, high selectivity, and physical and chemical stability when used in acidic media in a redox energy storage system. Of the twelve systems selected for study, only the system that was based on crosslinked poly-4-vinylpyridinium chloride produced physically strong membranes when equilibrated in l M HCl. The resistivity of the best membrane was 12 ohm-cm, and the transference number for chloride ions was 0.81.

  14. Transport behaviors of anionic azo dyes at interface between surfactant-modified flax shives and aqueous solution: Synchrotron infrared and adsorption studies

    NASA Astrophysics Data System (ADS)

    Wang, Wenxia; Huang, Guohe; An, Chunjiang; Xin, Xiaying; Zhang, Yan; Liu, Xia

    2017-05-01

    From the viewpoint of sustainability, biomass adsorbent has a high potential in pollution control and there is an emerging interest to investigate the behaviors of pollutants at the interface between biomass adsorbent and solution. This study investigated the performance of cetyltrimethylammonium bromide surfactant-modified flax shives (MFS) for removal of anionic azo dyes from aqueous solution. The equilibrium and kinetic analysis for the adsorption of Acid Orange 7 (AO-7), Acid Red 18 (AR-18) and Acid Black 1 (AB-1) on MFS were conducted. The surface of MFS was characterized by synchrotron infrared and SEM analysis. The absorbed amount of three anionic azo dyes varied with the change of adsorbent dosage, pH and ionic strength. The adsorption isotherm data well fit to the Langmuir model. The adsorption process followed the pseudo-second-order kinetics and the liquid film diffusion models. Thermodynamic studies indicated that the adsorption of three anionic azo dyes was spontaneous. The adsorption of AR-18 and AB-1 onto MFS was endothermic while the adsorption of AO-7 was exothermic. The results can help better understand the behaviors of organic pollutants at biomass adsorbent-water interface. They also present the potential of using MFS as a suitable adsorbent for the removal of anionic azo dyes from wastewater.

  15. Elevational Variation in Soil Amino Acid and Inorganic Nitrogen Concentrations in Taibai Mountain, China.

    PubMed

    Cao, Xiaochuang; Ma, Qingxu; Zhong, Chu; Yang, Xin; Zhu, Lianfeng; Zhang, Junhua; Jin, Qianyu; Wu, Lianghuan

    2016-01-01

    Amino acids are important sources of soil organic nitrogen (N), which is essential for plant nutrition, but detailed information about which amino acids predominant and whether amino acid composition varies with elevation is lacking. In this study, we hypothesized that the concentrations of amino acids in soil would increase and their composition would vary along the elevational gradient of Taibai Mountain, as plant-derived organic matter accumulated and N mineralization and microbial immobilization of amino acids slowed with reduced soil temperature. Results showed that the concentrations of soil extractable total N, extractable organic N and amino acids significantly increased with elevation due to the accumulation of soil organic matter and the greater N content. Soil extractable organic N concentration was significantly greater than that of the extractable inorganic N (NO3--N + NH4+-N). On average, soil adsorbed amino acid concentration was approximately 5-fold greater than that of the free amino acids, which indicates that adsorbed amino acids extracted with the strong salt solution likely represent a potential source for the replenishment of free amino acids. We found no appreciable evidence to suggest that amino acids with simple molecular structure were dominant at low elevations, whereas amino acids with high molecular weight and complex aromatic structure dominated the high elevations. Across the elevational gradient, the amino acid pool was dominated by alanine, aspartic acid, glycine, glutamic acid, histidine, serine and threonine. These seven amino acids accounted for approximately 68.9% of the total hydrolyzable amino acid pool. The proportions of isoleucine, tyrosine and methionine varied with elevation, while soil major amino acid composition (including alanine, arginine, aspartic acid, glycine, histidine, leucine, phenylalanine, serine, threonine and valine) did not vary appreciably with elevation (p>0.10). The compositional similarity of many

  16. Elevational Variation in Soil Amino Acid and Inorganic Nitrogen Concentrations in Taibai Mountain, China

    PubMed Central

    Yang, Xin; Zhu, Lianfeng; Zhang, Junhua; Jin, Qianyu; Wu, Lianghuan

    2016-01-01

    Amino acids are important sources of soil organic nitrogen (N), which is essential for plant nutrition, but detailed information about which amino acids predominant and whether amino acid composition varies with elevation is lacking. In this study, we hypothesized that the concentrations of amino acids in soil would increase and their composition would vary along the elevational gradient of Taibai Mountain, as plant-derived organic matter accumulated and N mineralization and microbial immobilization of amino acids slowed with reduced soil temperature. Results showed that the concentrations of soil extractable total N, extractable organic N and amino acids significantly increased with elevation due to the accumulation of soil organic matter and the greater N content. Soil extractable organic N concentration was significantly greater than that of the extractable inorganic N (NO3−-N + NH4+-N). On average, soil adsorbed amino acid concentration was approximately 5-fold greater than that of the free amino acids, which indicates that adsorbed amino acids extracted with the strong salt solution likely represent a potential source for the replenishment of free amino acids. We found no appreciable evidence to suggest that amino acids with simple molecular structure were dominant at low elevations, whereas amino acids with high molecular weight and complex aromatic structure dominated the high elevations. Across the elevational gradient, the amino acid pool was dominated by alanine, aspartic acid, glycine, glutamic acid, histidine, serine and threonine. These seven amino acids accounted for approximately 68.9% of the total hydrolyzable amino acid pool. The proportions of isoleucine, tyrosine and methionine varied with elevation, while soil major amino acid composition (including alanine, arginine, aspartic acid, glycine, histidine, leucine, phenylalanine, serine, threonine and valine) did not vary appreciably with elevation (p>0.10). The compositional similarity of many

  17. Blood concentrations of amino acids, glucose and lactate during experimental swine dysentery.

    PubMed

    Jonasson, R; Essén-Gustavsson, B; Jensen-Waern, M

    2007-06-01

    The aim of this study was to examine blood concentrations of amino acids, glucose and lactate in association with experimental swine dysentery. Ten pigs (approximately 23kg) were orally inoculated with Brachyspira hyodysenteriae. Eight animals developed muco-haemorrhagic diarrhoea with impaired general appearance, changes in white blood cell counts and increased levels of the acute phase protein Serum Amyolid A. Blood samples were taken before inoculation, during the incubation period, during clinical signs of dysentery and during recovery. Neither plasma glucose nor lactate concentrations changed during the course of swine dysentery, but the serum concentrations of gluconeogenic non-essential amino acids decreased during dysentery. This was mainly due to decreases in alanine, glutamine, serine and tyrosine. Lysine increased during dysentery and at the beginning of the recovery period, and leucine increased during recovery. Glutamine, alanine and tyrosine levels show negative correlations with the numbers of neutrophils and monocytes. In conclusion, swine dysentery altered the blood concentrations of amino acids, but not of glucose or lactate.

  18. Sex Steroid Modulation of Fatty Acid Utilization and Fatty Acid Binding Protein Concentration in Rat Liver

    PubMed Central

    Ockner, Robert K.; Lysenko, Nina; Manning, Joan A.; Monroe, Scott E.; Burnett, David A.

    1980-01-01

    The mechanism by which sex steroids influence very low density hepatic lipoprotein triglyceride production has not been fully elucidated. In previous studies we showed that [14C]oleate utilization and incorporation into triglycerides were greater in hepatocyte suspensions from adult female rats than from males. The sex differences were not related to activities of the enzymes of triglyceride biosynthesis, whereas fatty acid binding protein (FABP) concentration in liver cytosol was greater in females. These findings suggested that sex differences in lipoprotein could reflect a sex steroid influence on the availability of fatty acids for hepatocellular triglyceride biosynthesis. In the present studies, sex steroid effects on hepatocyte [14C]oleate utilization and FABP concentration were investigated directly. Hepatocytes from immature (30-d-old) rats exhibited no sex differences in [14C]oleate utilization. With maturation, total [14C]oleate utilization and triglyceride biosynthesis increased moderately in female cells and decreased markedly in male cells; the profound sex differences in adults were maximal by age 60 d. Fatty acid oxidation was little affected. Rats were castrated at age 30 d, and received estradiol, testosterone, or no hormone until age 60 d, when hepatocyte [14C]oleate utilization was studied. Castration virtually eliminated maturational changes and blunted the sex differences in adults. Estradiol or testosterone largely reproduced the appropriate adult pattern of [14C]oleate utilization regardless of the genotypic sex of the treated animal. In immature females and males, total cytosolic FABP concentrations were similar. In 60-d-old animals, there was a striking correlation among all groups (females, males, castrates, and hormone-treated) between mean cytosolic FABP concentration on the one hand, and mean total [14C]oleate utilization (r = 0.91) and incorporation into triglycerides (r = 0.94) on the other. In 30-d-old animals rates of [14C

  19. Concentrations of amino acids in plasma from 45- to 47-week gestation mares and foetuses (Equus caballus).

    PubMed

    Zicker, S C; Vivrette, S; Rogers, Q R

    1994-06-01

    Concentrations of 16 of 24 amino acids in plasma of foetuses were significantly higher, while four of 24 were lower, than their concentration in maternal plasma. The higher foetal concentrations of amino acids in plasma are similar to other species, with some exceptions, and suggest that equine placenta actively transports and concentrates amino acids into the umbilical circulation. Concentrations of nine of 24 amino acids were significantly lower in plasma from the umbilical artery compared to plasma from the umbilical vein, while no significant differences were present between maternal artery and vein plasma. The umbilical venous-arterial difference in concentrations of amino acids in plasma suggests the foetus extracts amino acids from the umbilical circulation for catabolism or protein synthesis, as in other species.

  20. Hydrothermal syntheses and anion-induced structural transformation of three Cadmium phosphonates

    NASA Astrophysics Data System (ADS)

    Hu, Han; Zhai, Fupeng; Liu, Xiaofeng; Ling, Yun; Chen, Zhenxia; Zhou, Yaming

    2018-05-01

    Three cadmium phosphonate coordinated polymers, namely as [Cd5(ptz)3(SO4)2(5H2O)]·6H2O (Cdptz-1), [Cd3(ptz)2(Cl)2(4H2O)]·2H2O (Cdptz-2) and [Cd4(ptz)2(SO4)(Cl)(OH)H2O]·H2O (Cdptz-3) have been hydrothermally synthesized using 4-(1,2,4-triazol-4-yl)phenylphosphonic acid (H2ptz) as ligand. Single crystal X-ray analyses revealed Cdptz-2 as layered structure and Cdptz-1,3 as pillar-layered structures with Cl- or SO42- as bridging anions. Due to the weak bonding between metal and anions, Cdptz-1 and 2 can reversibly convert into each other by simple immersing in the corresponding solution at room temperature. While the transformations between Cdptz-1,2 and Cdptz-3 can only happen under hydrothermal condition. The causes for the transformation involve the metal-ligand bond breaking/formation, replacement of anions and enhancement/decrement of the network dimensionality.

  1. Amino acid concentrations in the nectars of Southern African bird-pollinated flowers, especially aloe and erythrina.

    PubMed

    Nicolson, Susan W

    2007-09-01

    Amino acids in nectar have received less attention than the more abundant sugars. The dilute nectars of 32 species of southern African plants that are pollinated by passerine birds were analyzed by HPLC, and the effect of pollen contamination and the variation among inflorescences and plants were also examined. Aloe marlothii and some Erythrina species were found to have high total amino acid concentrations, sometimes exceeding 100 mM. Other Aloe species, as well as Greyia, Strelitzia, Schotia, Cotyledon, and Melianthus, had low nectar amino acid concentrations. Total amino acid concentrations varied much more than the sugar concentrations of these nectars as measured with a refractometer. Pollen contamination, previously claimed to be a major source of error in the measurement of nectar amino acids, had no effect on amino acids in the nectar of A. marlothii. Variation among inflorescences of Erythrina lysistemon was greater than that among trees, and most of the variation was because of relatively abundant nonessential amino acids such as asparagine and glutamine. High amino acid concentrations, especially in 'dilute' nectars, represent a substantial contribution of nonsugar solutes to 'sugar' concentrations measured with a refractometer. Amino acids in nectar may contribute to the nitrogen requirements of bird pollinators.

  2. Concentration and fractionation of hydrophobic organic acid constituents from natural waters by liquid chromatography

    USGS Publications Warehouse

    Thurman, E.M.; Malcolm, R.L.

    1979-01-01

    A scheme is presented which used adsorption chromatography with pH gradient elution and size-exclusion chromatography to concentrate and separate hydrophobic organic acids from water. A review of chromatographic processes involved in the flow scheme is also presented. Organic analytes which appear in each aqueous fraction are quantified by dissolved organic carbon analysis. Hydrophobic organic acids in a water sample are concentrated on a porous acrylic resin. These acids usually constitute approximately 30-50 percent of the dissolved organic carbon in an unpolluted water sample and are eluted with an aqueous eluent (dilute base). The concentrate is then passed through a column of polyacryloylmorpholine gel, which separates the acids into high- and low-molecular-weight fractions. The high- and low-molecular-weight eluates are reconcentrated by adsorption chromatography, then are eluted with a pH gradient into strong acids (predominately carboxylic acids) and weak acids (predominately phenolic compounds). For standard compounds and samples of unpolluted waters, the scheme fractionates humic substances into strong and weak acid fractions that are separated from the low molecular weight acids. A new method utilizing conductivity is also presented to estimate the acidic components in the methanol fraction.

  3. Aza-Bambusurils En Route to Anion Transporters.

    PubMed

    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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Towards the Rational Design of Ionic Liquid Matrices for Secondary Ion Mass Spectrometry: Role of the Anion

    NASA Astrophysics Data System (ADS)

    Dertinger, Jennifer J.; Walker, Amy V.

    2013-08-01

    The role of the ionic liquid (IL) anion structure on analyte signal enhancements has been systematically investigated in secondary ion mass spectrometry (SIMS) using a variety of samples, including lipids, sterols, polymers, and peptides. Twenty-four ILs were synthesized. The 12 matrix acids were cinnamic acid derivatives. Two bases were employed: 1-methylimidazole and tripropylamine. Three matrices, methylimmidazolium o-coumarate, tripropylammonium o-coumarate, and tripropylammonium 3,4,5-trimethoxycinnamate, were "universal" matrices enhancing all analytes tested. The pKa of the matrix acid does not appear to have a strong effect on analyte ion intensities. Rather, it is observed that a single hydroxyl group on the anion aromatic ring leads to significantly increased molecular ion intensities. No analyte signal enhancements were observed for -CH3, -CF3 and -OCH3 groups present on the aromatic ring. The position of the -OH group on the aromatic ring also alters molecular ion intensity enhancements. As well as the chemical identity and position of substituents, the number of moieties on the aromatic ring may affect the analyte signal enhancements observed. These observations suggest that the activation of the IL anion aromatic ring is important for optimizing analyte signal intensities. The implications for SIMS imaging of complex structures, such as biological samples, are discussed.

  5. Are silver nanoparticles always toxic in the presence of environmental anions?

    PubMed

    Guo, Zhi; Chen, Guiqiu; Zeng, Guangming; Yan, Ming; Huang, Zhenzhen; Jiang, Luhua; Peng, Chuan; Wang, Jiajia; Xiao, Zhihua

    2017-03-01

    Increasing amounts of silver nanoparticles (AgNPs) are expected to enter the ecosystems where their toxicity in the environment is proposed. In this study, we exploited the effect of environmental anions on AgNP toxicity. AgNP were mixed with various environmental anions, and then exposed to Escherichia coli to determine the effect on bacteria growth inhibition. The results demonstrated that AgNP are not always toxic in the presence of sulfide, but can stimulate microbial growth at certain concentrations. Environmental chloride and phosphate anions cannot induce the stimulation because of their weak capacity to control the release of Ag + from AgNP. Ag + that released from AgNP is proven to be responsible for AgNP toxicity. Moreover, we found that AgNP toxicity is dependent on sulfuration rate. At the same sulfuration rate, AgNP shows an identical pattern of toxicity. This study indicates that only sulfide of the tested environmental anions can induce AgNP stimulation to microbial growth in a sulfuration rate dependent pattern and the toxicity originate from Ag + that released from AgNP. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Anion effects on anti-microbial activity of poly[1-vinyl-3-(2-sulfoethyl imidazolium betaine)].

    PubMed

    Garg, Godawari; Chauhan, Ghanshyam S; Gupta, Reena; Ahn, J-H

    2010-04-01

    Recent investigations in the anti-microbial properties of the functional polymers are predominantly focused on the structure of the cationic moieties. In the present study, we investigated that the nature of the anion present in polysulfobetaines affects activity against certain microorganisms and their anti-microbial properties have been rationalized in terms of the structure-activity relationship. Vinyl imidazolium-based polysulfobetaines were prepared by the quaternization of poly(N-vinyl imidazole) with sodium salt of 2-bromo ethanesulfonic acid. The bromide counter anion of the resulting polymer was exchanged with different anions to generate a series of polymers. These were characterized by FTIR, DSC, XRD, SEM, elemental analysis (C, H, N and S) and viscosity measurements. The anti-microbial activity studies were carried against three fungi (Aspergillus niger, Byssochlamys fulva and Mucor circenelliods) and two bacteria (Bacillus coagulans BTS-3 and Pseudomonas aeruginosa BTS-2). The nature of the anion affects the structure of polysulfobetaine by realignment of polymer chains. The anion-dependent anti-microbial properties of polysulfobetaines result from the interaction of the microbes at the polymer interface. Copyright 2009 Elsevier Inc. All rights reserved.

  7. Effect of uric acid on inflammatory COX-2 and ROS pathways in vascular smooth muscle cells.

    PubMed

    Oğuz, Nurgül; Kırça, Mustafa; Çetin, Arzu; Yeşilkaya, Akın

    2017-10-01

    Hyperuricemia is thought to play a role in cardiovascular diseases (CVD), including hypertension, coronary artery disease and atherosclerosis. However, exactly how uric acid contributes to these pathologies is unknown. An underlying mechanism of inflammatory diseases, such as atherosclerosis, includes enhanced production of cyclooxygenase-2 (COX-2) and superoxide anion. Here, we aimed to examine the effect of uric acid on inflammatory COX-2 and superoxide anion production and to determine the role of losartan. Primarily cultured vascular smooth muscle cells (VSMCs) were time and dose-dependently induced by uric acid and COX-2 and superoxide anion levels were measured. COX-2 levels were determined by ELISA, and superoxide anion was measured by the superoxide dismutase (SOD)-inhibitable reduction of ferricytochrome c method. Uric acid elevated COX-2 levels in a time-dependent manner. Angiotensin-II receptor blocker, losartan, diminished uric-acid-induced COX-2 elevation. Uric acid also increased superoxide anion level in VSMCs. Uric acid plays an important role in CVD pathogenesis by inducing inflammatory COX-2 and ROS pathways. This is the first study demonstrating losartan's ability to reduce uric-acid-induced COX-2 elevation.

  8. Solubilization of pyrene by anionic-nonionic mixed surfactants.

    PubMed

    Zhou, Wenjun; Zhu, Lizhong

    2004-06-18

    Surfactant-enhanced remediation (SER) is an effective approach for the removal of sorbed hydrophobic organic compounds from contaminated soils. The solubilization of pyrene by four anionic-nonionic mixed surfactants, sodium dodecyl sulfate (SDS) with Triton X-405 (TX405), Brij35, Brij58, and Triton X-100 (TX100), has been studied from measurements of the molar solubilization ratio (MSR), the micelle-water partition coefficient (Kmc), and the critical micelle concentration (CMC). The MSRs of pyrene in mixed surfactants are found to be larger than those predicted according to an ideal mixing rule. The mixing effect of anionic and nonionic surfactants on MSR for pyrene follows the order of SDS-TX405 > SDS-Brij35 > SDS-Brij58 > SDS-TX100 and increases with an increase in the hydrophile-lipophile balance (HLB) value of nonionic surfactant in mixed systems. In addition, the mixture of anionic and nonionic surfactants cause the Kmc value for pyrene to be greater than the ideal value in SDS-TX405 mixed system, but to be smaller than the ideal value in SDS-Brij35, SDS-Brij58, and SDS-TX100 mixed systems. Meanwhile, in the four mixed systems, the experimental CMCs are lower than the ideal CMCs at almost all mixed surfactant solution compositions. The mixing effect of anionic and nonionic surfactants on MSR for pyrene can be attributed to the conjunct or the net result of the negative deviation of the CMCs from ideal mixture and the increasing or decreasing Kmc.

  9. Strapped Calix[4]pyrroles Bearing an 1,3-Indanedione at a β-Pyrrolic Position: Chemodosimeters for the Cyanide Anion

    PubMed Central

    Kim, Sook-Hee; Hong, Seong-Jin; Yoo, Jaeduk; Kim, Sung Kuk; Sessler, Janathan L.; Lee, Chang-Hee

    2014-01-01

    A strapped calix[4]pyrrole bearing an 1,3-indanedione group at a β-pyrrolic position has been synthesized and studied as a ratiometric cyanide selective chemosensor. A concentration-dependent bleaching of the initial yellow color was observed upon addition of the cyanide anion. The bleaching, which was observed exclusively with the cyanide anion, occurred even in the presence of other anions. Spectroscopic studies provides support for a mechanistic interpretation wherein the cyanide anion forms a complex with the receptor (K = 2.78 × 104 M-1) through a fast equilibrium, which is followed by slow nucleophilic addition to the β-position of the 1,3-indanedione group. A minimum inhibitory effect from other anions was observed, a feature that could be beneficial in the selective sensing of the cyanide anion. PMID:19639968

  10. Enhancement of anion-exchange chromatography of DNA using compaction agents

    NASA Technical Reports Server (NTRS)

    Murphy, Jason C.; Fox, George E.; Willson, Richard C.

    2003-01-01

    The use of adsorptive chromatography for preparative nucleic acid separations is often limited by low capacity. The possibility that the adsorbent surface area sterically accessible to nucleic acid molecules could be increased by reducing their radius of gyration with compaction agents has been investigated. The equilibrium adsorption capacity of Q Sepharose anion-exchange matrix for plasmid DNA at 600 mM NaCl was enhanced by up to ca. 40% in the presence of 2.5 mM spermine. In addition, compaction agent selectivity has been demonstrated. Spermine, for example, enhances the adsorption of both plasmid and genomic DNA, spermidine enhances binding only of plasmid, and hexamine cobalt enhances only the binding of genomic DNA. Compaction may be generally useful for enhancing adsorptive separations of nucleic acids.

  11. Serum uric acid concentrations are directly associated with the presence of benign multiple sclerosis.

    PubMed

    Simental-Mendía, Esteban; Simental-Mendía, Luis E; Guerrero-Romero, Fernando

    2017-09-01

    It has been reported that patients with multiple sclerosis (MS) exhibit lower serum uric acid levels; however, the association between uric acid concentrations and benign MS (BMS) has not been assessed. Hence, the objective of the present study was to determine whether the serum concentrations of uric acid are associated with the presence of BMS. Men and non-pregnant women over 16 years of age with diagnosis of MS were enrolled in a cross-sectional study. Expanded Disability Status Scale score < 3, progression of disease ≤10 years, diabetes, renal or hepatic diseases, gout, malignancy, alcohol intake, and treatment with thiazide diuretics and/or acetylsalicylic acid were exclusion criteria. According to subtype of disease, the eligible patients were allocated into groups with BMS and other varieties of MS. A logistic regression analysis was conducted in order to evaluate the association between serum concentrations of uric acid and BMS. A total of 106 patients were included, 39 in the group with BMS and 67 in the group with other varieties of MS. The logistic regression analysis adjusted by age, sex, and disease duration showed that increased concentrations of uric acid, indeed within the physiological levels, are significantly associated with the presence of BMS (OR = 2.60; 95% CI: 1.55-4.38, p < 0.001). The results of the present study suggest that elevated concentrations of uric acid, indeed within the physiological range, are likely linked to the presence of BMS.

  12. Are carboxyl groups the most acidic sites in amino acids? Gas-phase acidities, photoelectron spectra, and computations on tyrosine, p-hydroxybenzoic acid, and their conjugate bases.

    PubMed

    Tian, Zhixin; Wang, Xue-Bin; Wang, Lai-Sheng; Kass, Steven R

    2009-01-28

    Deprotonation of tyrosine in the gas phase was found to occur preferentially at the phenolic site, and the conjugate base consists of a 70:30 mixture of phenoxide and carboxylate anions at equilibrium. This result was established by developing a chemical probe for differentiating these two isomers, and the presence of both ions was confirmed by photoelectron spectroscopy. Equilibrium acidity measurements on tyrosine indicated that deltaG(acid)(o) = 332.5 +/- 1.5 kcal mol(-1) and deltaH(acid)(o) = 340.7 +/- 1.5 kcal mol(-1). Photoelectron spectra yielded adiabatic electron detachment energies of 2.70 +/- 0.05 and 3.55 +/- 0.10 eV for the phenoxide and carboxylate anions, respectively. The H/D exchange behavior of deprotonated tyrosine was examined using three different alcohols (CF3CH2OD, C6H5CH2OD, and CH3CH2OD), and incorporation of up to three deuterium atoms was observed. Two pathways are proposed to account for these results, and all of the experimental findings are supplemented with B3LYP/aug-cc-pVDZ and G3B3 calculations. In addition, it was found that electrospray ionization of tyrosine from a 3:1 (v/v) CH3OH/H2O solution using a commercial source produces a deprotonated [M-H]- anion with the gas-phase equilibrium composition rather than the structure of the ion that exists in aqueous media. Electrospray ionization from acetonitrile, however, leads largely to the liquid-phase (carboxylate) structure. A control molecule, p-hydroxybenzoic acid, was found to behave in a similar manner. Thus, the electrospray conditions that are employed for the analysis of a compound can alter the isomeric composition of the resulting anion.

  13. Tip-localized Ca2+ -permeable channels control pollen tube growth via kinase-dependent R- and S-type anion channel regulation.

    PubMed

    Gutermuth, Timo; Herbell, Sarah; Lassig, Roman; Brosché, Mikael; Romeis, Tina; Feijó, José Alberto; Hedrich, Rainer; Konrad, Kai Robert

    2018-05-01

    Pollen tubes (PTs) are characterized by having tip-focused cytosolic calcium ion (Ca 2+ ) concentration ([Ca 2+ ] cyt ) gradients, which are believed to control PT growth. However, the mechanisms by which the apical [Ca 2+ ] cyt orchestrates PT growth are not well understood. Here, we aimed to identify these mechanisms by combining reverse genetics, cell biology, electrophysiology, and live-cell Ca 2+ and anion imaging. We triggered Ca 2+ -channel activation by applying hyperpolarizing voltage pulses and observed that the evoked [Ca 2+ ] cyt increases were paralleled by high anion channel activity and a decrease in the cytosolic anion concentration at the PT tip. We confirmed a functional correlation between these patterns by showing that inhibition of Ca 2+ -permeable channels eliminated the [Ca 2+ ] cyt increase, resulting in the abrogation of anion channel activity via Ca 2+ -dependent protein kinases (CPKs). Functional characterization of CPK and anion-channel mutants revealed a CPK2/20/6-dependent activation of SLAH3 and ALMT12/13/14 anion channels. The impaired growth phenotypes of anion channel and CPK mutants support the physiological significance of a kinase- and Ca 2+ -dependent pathway to control PT growth via anion channel activation. Other than unveiling this functional link, our membrane hyperpolarization method allows for unprecedented manipulation of the [Ca 2+ ] cyt gradient or oscillations in the PT tips and opens an array of opportunities for channel screenings. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  14. MinD and MinE Interact with Anionic Phospholipids and Regulate Division Plane Formation in Escherichia coli*

    PubMed Central

    Renner, Lars D.; Weibel, Douglas B.

    2012-01-01

    The Min proteins (MinC, MinD, and MinE) form a pole-to-pole oscillator that controls the spatial assembly of the division machinery in Escherichia coli cells. Previous studies identified that interactions of MinD with phospholipids positioned the Min machinery at the membrane. We extend these studies by measuring the affinity, kinetics, and ATPase activity of E. coli MinD, MinE, and MinDE binding to supported lipid bilayers containing varying compositions of anionic phospholipids. Using quartz crystal microbalance measurements, we found that the binding affinity (Kd) for the interaction of recombinant E. coli MinD and MinE with lipid bilayers increased with increasing concentration of the anionic phospholipids phosphatidylglycerol and cardiolipin. The Kd for MinD (1.8 μm) in the presence of ATP was smaller than for MinE (12.1 μm) binding to membranes consisting of 95:5 phosphatidylcholine/cardiolipin. The simultaneous binding of MinD and MinE to membranes revealed that increasing the concentration of anionic phospholipid stimulates the initial rate of adsorption (kon). The ATPase activity of MinD decreased in the presence of anionic phospholipids. These results indicate that anionic lipids, which are concentrated at the poles, increase the retention of MinD and MinE and explain its dwell time at this region of bacterial cells. These studies provide insight into interactions between MinD and MinE and between these proteins and membranes that are relevant to understanding the process of bacterial cell division, in which the interaction of proteins and membranes is essential. PMID:23012351

  15. Effect of the pore water composition on the diffusive anion transport in argillaceous, low permeability sedimentary rocks

    NASA Astrophysics Data System (ADS)

    Wigger, Cornelia; Van Loon, Luc R.

    2018-06-01

    The effect of the pore water composition on the diffusive anion transport was studied for two different argillaceous, low permeability sedimentary rocks, Opalinus Clay (OPA) and Helvetic Marl (HM). The samples were saturated with different solutions with varying molar concentration and different main cations in the solution: NaCl based pore solutions and CaCl2 based pore solutions. The total porosity was measured by through-diffusion experiments with the neutral tracer HTO. Experiments performed in NaCl solutions resulted in a porosity of 0.12 for OPA and 0.03 for HM, and are consistent with results of the experiments in CaCl2 solutions. The total porosity was independent of the molar concentration, in contrast to the measured anion porosity, which increased with increasing molar concentration. It could further be observed that the pore solution based on the bivalent cation calcium shielded the negative surface charge stronger than the monovalent cation sodium, resulting in a larger measureable anion-accessible porosity in the case of CaCl2 solutions. The data was modelled based on an adapted Donnan approach of Birgersson and Karnland (2009). The model had to be adjusted with a permanent free, uncharged porosity, as well as with structural information on the permanent anion exclusion because of so-called bottleneck pores. Both parameters can only be evaluated from experiments. Nevertheless, taking these two adaptions into account, the effect of varying pore water compositions on the anion-accessible porosity of the investigated argillaceous rocks could be satisfactorily described.

  16. Effect of the pore water composition on the diffusive anion transport in argillaceous, low permeability sedimentary rocks.

    PubMed

    Wigger, Cornelia; Van Loon, Luc R

    2018-06-01

    The effect of the pore water composition on the diffusive anion transport was studied for two different argillaceous, low permeability sedimentary rocks, Opalinus Clay (OPA) and Helvetic Marl (HM). The samples were saturated with different solutions with varying molar concentration and different main cations in the solution: NaCl based pore solutions and CaCl 2 based pore solutions. The total porosity was measured by through-diffusion experiments with the neutral tracer HTO. Experiments performed in NaCl solutions resulted in a porosity of 0.12 for OPA and 0.03 for HM, and are consistent with results of the experiments in CaCl 2 solutions. The total porosity was independent of the molar concentration, in contrast to the measured anion porosity, which increased with increasing molar concentration. It could further be observed that the pore solution based on the bivalent cation calcium shielded the negative surface charge stronger than the monovalent cation sodium, resulting in a larger measureable anion-accessible porosity in the case of CaCl 2 solutions. The data was modelled based on an adapted Donnan approach of Birgersson and Karnland (2009). The model had to be adjusted with a permanent free, uncharged porosity, as well as with structural information on the permanent anion exclusion because of so-called bottleneck pores. Both parameters can only be evaluated from experiments. Nevertheless, taking these two adaptions into account, the effect of varying pore water compositions on the anion-accessible porosity of the investigated argillaceous rocks could be satisfactorily described. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Association between the blood concentrations of ammonia and carnitine/amino acid of schizophrenic patients treated with valproic acid.

    PubMed

    Ando, Masazumi; Amayasu, Hideaki; Itai, Takahiro; Yoshida, Hisahiro

    2017-01-01

    Administration of valproic acid (VPA) is complicated with approximately 0.9% of patients developing hyperammonemia, but the pathogenesis of this adverse effect remains to be clarified. The aim of the present study was to search for mechanisms associated with VPA-induced hyperammonemia in the light of changes in serum amino acids concentrations associated with the urea cycle of schizophrenic patients. Blood samples (10 mL) were obtained from 37 schizophrenic patients receiving VPA for the prevention of violent behaviors in the morning after overnight fast. Blood concentrations of ammonia, VPA, free carnitine, acyl-carnitine, and 40 amino acids including glutamate and citrulline were measured for each patient. Univariate and multivariate regression analyses were performed to identify amino acids or concomitantly administered drugs that were associated with variability in the blood concentrations of ammonia. The blood ammonia level was positively correlated with the serum glutamate concentration ( r  = 0.44, p  < 0.01) but negatively correlated with glutamine ( r  = -0.41, p  = 0.01), citrulline ( r  = -0.42, p  = 0.01), and glycine concentrations ( r  = -0.54, p  < 0.01). It was also revealed that the concomitant administration of the mood stabilizers ( p  = 0.04) risperidone ( p  = 0.03) and blonanserin ( p  < 0.01) was positively associated with the elevation of the blood ammonia level. We hypothisized that VPA would elevate the blood ammonia level of schizophrenic patients. The observed changes in serum amino acids are compatible with urea cycle dysfunction, possibly due to reduced carbamoyl-phosphate synthase 1 (CPS1) activity. We conclude that VPA should be prudently prescribed to schizophrenic patients, particularly those receiving mood stabilizers or certain antipsychotics.

  18. Effect of antacid and ascorbic acid on serum salicylate concentration.

    PubMed

    Hansten, P D; Hayton, W L

    1980-01-01

    To determine the effect of antacid or ascorbic acid administration on plateau serum salicylate concentrations, nine healthy subjects were given each of the following treatments by balanced block design: choline salicylate (equivalent to 3.76 or 5.62 Gm/day of aspirin); choline salicylate plus magnesium-aluminum hydroxide (120 ml/day); or choline salicylate plus ascorbic acid (3 Gm/day). In subjects developing a control serum salicylate level above 10 mg/dl, antacid administration produced a decrease in serum salicylate level (mean 19.8 mg/dl vs. 15.8 mg/dl) (P less than 0.01). Ascorbic acid administration was not associated with a significant change in serum salicylate. The reduction in serum salicylate following antacid appears to be due to antacid-induced alkalinization of the urine with resultant increase in renal salicylate clearance. Antacid administration should be considered a potential cause of altered serum salicylate concentration in patients receiving large doses of salicylate.

  19. Concentration methods for high-resolution THz spectroscopy of nucleic-acid biomolecules and crystals

    NASA Astrophysics Data System (ADS)

    Brown, E. R.; Zhang, W.; Mendoza, E. A.; Kuznetsova, Y.; Brueck, S. R. J.; Rahman, M.; Norton, M. L.

    2012-03-01

    Biomolecules can exhibit low-lying vibrational modes in the THz region which are detectable in transmission given a strong molecular dipole moment and optical depth, and a spectrometer of adequate sensitivity. The nucleic acids are particularly interesting because of applications such as label-free gene assay, bio-agent detection, etc. However for nucleic acids, sample preparation and THz coupling are of paramount importance because of the strong absorption by liquid water and the small concentration of molecules present in physiological solutions. Concentration methods become necessary to make the THz vibrational modes detectable, either by concentrating the nucleic-acid sample itself in a small volume but large area, or by concentrating the THz radiation down to the volume of the sample. This paper summarizes one type of the first method: nanofluidic channel arrays for biological nucleic acids; and two types of the second method: (1) a circular-waveguide pinhole, and (2) a circular-waveguide, conical-horn coupling structure, both for DNA crystals. The first method has been demonstrated on a very short artificial nucleic acid [small-interfering (si) RNA (17-to-25 bp)] and a much longer, biological molecule [Lambda-phage DNA (48.5 kbp)]. The second method has been demonstrated on small (~100 micron) single crystals of DNA grown by the sitting-drop method.

  20. Synergistic Anion-(π) n-π Catalysis on π-Stacked Foldamers.

    PubMed

    Bornhof, Anna-Bea; Bauzá, Antonio; Aster, Alexander; Pupier, Marion; Frontera, Antonio; Vauthey, Eric; Sakai, Naomi; Matile, Stefan

    2018-04-11

    In this report, we demonstrate that synergistic effects between π-π stacking and anion-π interactions in π-stacked foldamers provide access to unprecedented catalytic activity. To elaborate on anion-(π) n -π catalysis, we have designed, synthesized and evaluated a series of novel covalent oligomers with up to four face-to-face stacked naphthalenediimides (NDIs). NMR analysis including DOSY confirms folding into π stacks, cyclic voltammetry, steady-state and transient absorption spectroscopy the electronic communication within the π stacks. Catalytic activity, assessed by chemoselective catalysis of the intrinsically disfavored but biologically relevant addition reaction of malonate half thioesters to enolate acceptors, increases linearly with the length of the stacks to reach values that are otherwise beyond reach. This linear increase violates the sublinear power laws of oligomer chemistry. The comparison of catalytic activity with ratiometric changes in absorption and decreasing energy of the LUMO thus results in superlinearity, that is synergistic amplification of anion-π catalysis by remote control over the entire stack. In computational models, increasing length of the π-stacked foldamers correlates sublinearly with changes in surface potentials, chloride binding energies, and the distances between chloride and π surface and within the π stack. Computational evidence is presented that the selective acceleration of disfavored but relevant enolate chemistry by anion-π catalysis indeed originates from the discrimination of planar and bent tautomers with delocalized and localized charges, respectively, on π-acidic surfaces. Computed binding energies of keto and enol intermediates of the addition reaction as well as their difference increase with increasing length of the π stack and thus reflect experimental trends correctly. These results demonstrate that anion-(π) n -π interactions exist and matter, ready for use as a unique new tool in catalysis

  1. Use of extractive distillation to produce concentrated nitric acid

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

    Campbell, P.C.; Griffin, T.P.; Irwin, C.F.

    1981-04-01

    Concentrated nitric acid (> 95 wt %) is needed for the treatment of off-gases from a fuels-reprocessing plant. The production of concentrated nitric acid by means of extractive distillation in the two-pot apparatus was studied to determine the steady-state behavior of the system. Four parameters, EDP volume (V/sub EDP/) and temperature (T/sub EDP/), acid feed rate, and solvent recycle, were independently varied. The major response factors were percent recovery (CPRR) and product purity (CCP). Stage efficiencies also provided information about the system response. Correlations developed for the response parameters are: CPRR = 0.02(V/sub EDP/ - 800 cc) + 53.5; CCPmore » = -0.87 (T/sub EDP/ - 140/sup 0/C) + 81; eta/sub V,EDP/ = 9.1(F/sub feed/ - 11.5 cc/min) - 0.047(V/sub EDP/ - 800 cc) - 2.8(F/sub Mg(NO/sub 3/)/sub 2// - 50 cc/min) + 390; and eta/sub L,EDP/ = 1.9(T/sub EDP/ - 140/sup 0/C) + 79. A computer simulation of the process capable of predicting steady-state conditions was developed, but it requires further work.« less

  2. Geochemical modeling of reactions and partitioning of trace metals and radionuclides during titration of contaminated acidic sediments.

    PubMed

    Zhang, Fan; Luo, Wensui; Parker, Jack C; Spalding, Brian P; Brooks, Scott C; Watson, David B; Jardine, Philip M; Gu, Baohua

    2008-11-01

    Many geochemical reactions that control aqueous metal concentrations are directly affected by solution pH. However, changes in solution pH are strongly buffered by various aqueous phase and solid phase precipitation/dissolution and adsorption/desorption reactions. The ability to predict acid-base behavior of the soil-solution system is thus critical to predict metal transport under variable pH conditions. This studywas undertaken to develop a practical generic geochemical modeling approach to predict aqueous and solid phase concentrations of metals and anions during conditions of acid or base additions. The method of Spalding and Spalding was utilized to model soil buffer capacity and pH-dependent cation exchange capacity by treating aquifer solids as a polyprotic acid. To simulate the dynamic and pH-dependent anion exchange capacity, the aquifer solids were simultaneously treated as a polyprotic base controlled by mineral precipitation/ dissolution reactions. An equilibrium reaction model that describes aqueous complexation, precipitation, sorption and soil buffering with pH-dependent ion exchange was developed using HydroGeoChem v5.0 (HGC5). Comparison of model results with experimental titration data of pH, Al, Ca, Mg, Sr, Mn, Ni, Co, and SO4(2-) for contaminated sediments indicated close agreement suggesting that the model could potentially be used to predictthe acid-base behavior of the sediment-solution system under variable pH conditions.

  3. Simultaneous determination of inorganic anions and cations in explosive residues by ion chromatography.

    PubMed

    Meng, Hong-Bo; Wang, Tian-Ran; Guo, Bao-Yuan; Hashi, Yuki; Guo, Can-Xiong; Lin, Jin-Ming

    2008-07-15

    A non-suppressed ion chromatographic method by connecting anion-exchange and cation-exchange columns directly was developed for the separation and determination of five inorganic anions (sulfate, nitrate, chloride, nitrite, and chlorate) and three cations (sodium, ammonium, and potassium) simultaneously in explosive residues. The mobile phase was composed of 3.5mM phthalic acid with 2% acetonitrile and water at flow rate of 0.2 mL/min. Under the optimal conditions, the eight inorganic ions were completely separated and detected simultaneously within 16 min. The limits of detection (S/N=3) of the anions and cations were in the range of 50-100 microg/L and 150-320 microg/L, respectively, the linear correlation coefficients were 0.9941-0.9996, and the R.S.D. of retention time and peak area were 0.10-0.29% and 5.65-8.12%, respectively. The method was applied successfully to the analysis of the explosive samples with satisfactory results.

  4. Ion exchange polymers for anion separations

    DOEpatents

    Jarvinen, Gordon D.; Marsh, S. Fredric; Bartsch, Richard A.

    1997-01-01

    Anion exchange resins including at least two positively charged sites and a ell-defined spacing between the positive sites are provided together with a process of removing anions or anionic metal complexes from aqueous solutions by use of such resins. The resins can be substituted poly(vinylpyridine) and substituted polystyrene.

  5. Ion exchange polymers for anion separations

    DOEpatents

    Jarvinen, G.D.; Marsh, S.F.; Bartsch, R.A.

    1997-09-23

    Anion exchange resins including at least two positively charged sites and a well-defined spacing between the positive sites are provided together with a process of removing anions or anionic metal complexes from aqueous solutions by use of such resins. The resins can be substituted poly(vinylpyridine) and substituted polystyrene.

  6. Cytosolic Nucleotides Block and Regulate the Arabidopsis Vacuolar Anion Channel AtALMT9*

    PubMed Central

    Zhang, Jingbo; Martinoia, Enrico; De Angeli, Alexis

    2014-01-01

    The aluminum-activated malate transporters (ALMTs) form a membrane protein family exhibiting different physiological roles in plants, varying from conferring tolerance to environmental Al3+ to the regulation of stomatal movement. The regulation of the anion channels of the ALMT family is largely unknown. Identifying intracellular modulators of the activity of anion channels is fundamental to understanding their physiological functions. In this study we investigated the role of cytosolic nucleotides in regulating the activity of the vacuolar anion channel AtALMT9. We found that cytosolic nucleotides modulate the transport activity of AtALMT9. This modulation was based on a direct block of the pore of the channel at negative membrane potentials (open channel block) by the nucleotide and not by a phosphorylation mechanism. The block by nucleotides of AtALMT9-mediated currents was voltage dependent. The blocking efficiency of intracellular nucleotides increased with the number of phosphate groups and ATP was the most effective cellular blocker. Interestingly, the ATP block induced a marked modification of the current-voltage characteristic of AtALMT9. In addition, increased concentrations of vacuolar anions were able to shift the ATP block threshold to a more negative membrane potential. The block of AtALMT9-mediated anion currents by ATP at negative membrane potentials acts as a gate of the channel and vacuolar anion tune this gating mechanism. Our results suggest that anion transport across the vacuolar membrane in plant cells is controlled by cytosolic nucleotides and the energetic status of the cell. PMID:25028514

  7. Cytosolic nucleotides block and regulate the Arabidopsis vacuolar anion channel AtALMT9.

    PubMed

    Zhang, Jingbo; Martinoia, Enrico; De Angeli, Alexis

    2014-09-12

    The aluminum-activated malate transporters (ALMTs) form a membrane protein family exhibiting different physiological roles in plants, varying from conferring tolerance to environmental Al(3+) to the regulation of stomatal movement. The regulation of the anion channels of the ALMT family is largely unknown. Identifying intracellular modulators of the activity of anion channels is fundamental to understanding their physiological functions. In this study we investigated the role of cytosolic nucleotides in regulating the activity of the vacuolar anion channel AtALMT9. We found that cytosolic nucleotides modulate the transport activity of AtALMT9. This modulation was based on a direct block of the pore of the channel at negative membrane potentials (open channel block) by the nucleotide and not by a phosphorylation mechanism. The block by nucleotides of AtALMT9-mediated currents was voltage dependent. The blocking efficiency of intracellular nucleotides increased with the number of phosphate groups and ATP was the most effective cellular blocker. Interestingly, the ATP block induced a marked modification of the current-voltage characteristic of AtALMT9. In addition, increased concentrations of vacuolar anions were able to shift the ATP block threshold to a more negative membrane potential. The block of AtALMT9-mediated anion currents by ATP at negative membrane potentials acts as a gate of the channel and vacuolar anion tune this gating mechanism. Our results suggest that anion transport across the vacuolar membrane in plant cells is controlled by cytosolic nucleotides and the energetic status of the cell. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. NMR studies reveal the role of biomembranes in modulating ligand binding and release by intracellular bile acid binding proteins.

    PubMed

    Pedò, Massimo; Löhr, Frank; D'Onofrio, Mariapina; Assfalg, Michael; Dötsch, Volker; Molinari, Henriette

    2009-12-18

    Bile acid molecules are transferred vectorially between basolateral and apical membranes of hepatocytes and enterocytes in the context of the enterohepatic circulation, a process regulating whole body lipid homeostasis. This work addresses the role of the cytosolic lipid binding proteins in the intracellular transfer of bile acids between different membrane compartments. We present nuclear magnetic resonance (NMR) data describing the ternary system composed of the bile acid binding protein, bile acids, and membrane mimetic systems, such as anionic liposomes. This work provides evidence that the investigated liver bile acid binding protein undergoes association with the anionic membrane and binding-induced partial unfolding. The addition of the physiological ligand to the protein-liposome mixture is capable of modulating this interaction, shifting the equilibrium towards the free folded holo protein. An ensemble of NMR titration experiments, based on nitrogen-15 protein and ligand observation, confirm that the membrane and the ligand establish competing binding equilibria, modulating the cytoplasmic permeability of bile acids. These results support a mechanism of ligand binding and release controlled by the onset of a bile salt concentration gradient within the polarized cell. The location of a specific protein region interacting with liposomes is highlighted.

  9. Relationship Between Equilibrium Forms of Lysozyme Crystals and Precipitant Anions

    NASA Technical Reports Server (NTRS)

    Nadarajah, Arunan

    1996-01-01

    Molecular forces, such as electrostatic, hydrophobic, van der Waals and steric forces, are known to be important in determining protein interactions. These forces are affected by the solution conditions and changing the pH, temperature or the ionic strength of the solution can sharply affect protein interactions. Several investigations of protein crystallization have shown that this process is also strongly dependent on solution conditions. As the ionic strength of the solution is increased, the initially soluble protein may either crystallize or form an amorphous precipitate at high ionic strengths. Studies done on the model protein hen egg white lysozyme have shown that different crystal forms can be easily and reproducibly obtained, depending primarily on the anion used to desolubilize the protein. In this study we employ pyranine to probe the effect of various anions on the water structure. Additionally, lysozyme crystallization was carried out at these conditions and the crystal form was determined by X-ray crystallography. The goal of the study was to understand the physico-chemical basis for the effect of changing the anion concentration on the equilibrium form of lysozyme crystals. It will also verify the hypothesis that the anions, by altering the bulk water structure in the crystallizing solutions, alter the surface energy of the between the crystal faces and the solution and, consequently, the equilibrium form of the crystals.

  10. Concentrations of nitrous acid, nitric acid, nitrite and nitrate in the gas and aerosol phase at a site in the emission zone during ESCOMPTE 2001 experiment

    NASA Astrophysics Data System (ADS)

    Acker, K.; Möller, D.; Auel, R.; Wieprecht, W.; Kalaß, D.

    2005-03-01

    Ground-based measurements were performed at the "Expérience sur Site pour COntraindre les Modèles de Pollution atmosphérique et de Transport d`Emissions" (ESCOMPTE) field site E3 (Realtor) about 30 km north of the urban environment of Marseille and east of the industrial centre Berre pond to investigate the formation of nitrous and nitric acid and to detect the distribution of reactive N-species between the gas and particle phase during photochemical pollution events. A wet denuder sampling for gases followed by a steam jet collection for aerosols was both coupled to anion chromatographic analysis. The analytical system provided data continuously with 30-min time resolution between June 13 and July 13, 2001. Indications for heterogeneous formation of nitrous acid during nighttime and daytime on ground and aerosol surfaces were found, the average HNO 2/NO 2 ratio was 6%. Highest concentrations were observed during two episodes of strong pollution accumulation when sea breeze transported industrial, traffic and urban pollution land-inwards. After nocturnal heterogeneous formation (about 0.1 ppb v h -1 were estimated corresponding to increasing HNO 2/NO 2 ratios) and accumulation processes up to 1.2 ppb v HNO 2 were observed. Their photolysis produces up to 5-9×10 6 OH cm -3 s -1 and will contribute significantly to initiation of the daily photochemistry in the lowest part of the troposphere. For the key tropospheric species, HNO 3 daily peaks up to 4 ppb v were detected.

  11. Substrate transport and anion permeation proceed through distinct pathways in glutamate transporters

    PubMed Central

    Cheng, Mary Hongying; Torres-Salazar, Delany; Gonzalez-Suarez, Aneysis D; Amara, Susan G; Bahar, Ivet

    2017-01-01

    Advances in structure-function analyses and computational biology have enabled a deeper understanding of how excitatory amino acid transporters (EAATs) mediate chloride permeation and substrate transport. However, the mechanism of structural coupling between these functions remains to be established. Using a combination of molecular modeling, substituted cysteine accessibility, electrophysiology and glutamate uptake assays, we identified a chloride-channeling conformer, iChS, transiently accessible as EAAT1 reconfigures from substrate/ion-loaded into a substrate-releasing conformer. Opening of the anion permeation path in this iChS is controlled by the elevator-like movement of the substrate-binding core, along with its wall that simultaneously lines the anion permeation path (global); and repacking of a cluster of hydrophobic residues near the extracellular vestibule (local). Moreover, our results demonstrate that stabilization of iChS by chemical modifications favors anion channeling at the expense of substrate transport, suggesting a mutually exclusive regulation mediated by the movement of the flexible wall lining the two regions. DOI: http://dx.doi.org/10.7554/eLife.25850.001 PMID:28569666

  12. Effect of Anions on Nanofiber Formation of β-sheet Propensity Amphiphile Peptide

    NASA Astrophysics Data System (ADS)

    Shamsudeen, H.; Tan, H. L.; Eshak, Z.

    2018-05-01

    Peptide self-assembly forms different nanostructures under simple alteration in the solution environment. Understanding the mechanism of the assembly will help us to control and tailor functional nanomaterials. This study aims to investigate the influence of anions on the self-assembly morphology and shape using a synthetic peptide of FFFFKK. Circular Dichoism (CD) and Environmental Scanning Electron Microscope (ESEM) were used to determine the secondary structure and self-assembly morphology, while Image J imaging software was used to measure diameter size. In the absence of anion, FFFFKK formed anti-parallel β-sheet that adopted sizeable fibrillar structure with a minimal increment over the first 7 hours of assembly. Irregular structure was observed in the presence of Iodide ion (I-) with a less stable secondary structure such as β-turn and β-loop. In the presence of perchlorate ion (ClO4 -), needle-like structure was observed with predominantly β-sheet structure. Our study showed that peptide morphology can be controlled by using different anions with careful selection of amino acid residues in peptide sequence.

  13. Anions in Electrothermal Supercharging of Proteins with Electrospray Ionization Follow a Reverse Hofmeister Series

    PubMed Central

    2015-01-01

    The effects of different anions on the extent of electrothermal supercharging of proteins from aqueous ammonium and sodium salt solutions were investigated. Sulfate and hydrogen phosphate are the most effective anions at producing high charge state protein ions from buffered aqueous solution, whereas iodide and perchlorate are ineffective with electrothermal supercharging. The propensity for these anions to produce high charge state protein ions follows the following trend: sulfate > hydrogen phosphate > thiocyanate > bicarbonate > chloride > formate ≈ bromide > acetate > iodide > perchlorate. This trend correlates with the reverse Hofmeister series over a wide range of salt concentrations (1 mM to 2 M) and with several physical properties, including solvent surface tension, anion viscosity B-coefficient, and anion surface/bulk partitioning coefficient, all of which are related to the Hofmeister series. The effectiveness of electrothermal supercharging does not depend on bubble formation, either from thermal degradation of the buffer or from coalescence of dissolved gas. These results provide evidence that the effect of different ions in the formation of high charge state ions by electrothermal supercharging is largely a result of Hofmeister effects on protein stability leading to protein unfolding in the heated ESI droplet. PMID:24410546

  14. Effect of pH, competitive anions and NOM on the leaching of arsenic from solid residuals.

    PubMed

    Ghosh, Amlan; Sáez, A Eduardo; Ela, Wendell

    2006-06-15

    Implementation of the new arsenic MCL in 2006 will lead to the generation of an estimated 6 million pounds of arsenic-bearing solid residuals (ABSRs) every year, which will be disposed predominantly in non-hazardous landfills. The Toxicity Characteristic Leaching Procedure (TCLP) is typically used to assess whether a waste is hazardous and most solid residuals pass the TCLP. However, recent research shows the TCLP significantly underestimates arsenic mobilization in landfills. A variety of compositional dissimilarities between landfill leachates and the TCLP extractant solution likely play a role. Among the abiotic factors likely to play a key role in arsenic remobilization/leaching from solid sorbents are pH, and the concentrations of natural organic matter (NOM) and anions like phosphate, bicarbonate, sulfate and silicate. This study evaluates the desorption of arsenic from actual treatment sorbents, activated alumina (AA) and granular ferric hydroxide (GFH), which are representative of those predicted for use in arsenic removal processes, and as a function of the specific range of pH and concentrations of the competitive anions and NOM found in landfills. The influence of pH is much more significant than that of competing anions or NOM. An increase in one unit of pH may increase the fraction of arsenic leached by 3-4 times. NOM and phosphate replace arsenic from sorbent surface sites up to three orders of magnitude more than bicarbonate, sulfate and silicate, on a per mole basis. Effects of anions are neither additive nor purely competitive. Leaching tests, which compare the fraction of arsenic mobilized by the TCLP vis-a-vis an actual or more realistic synthetic landfill leachate, indicate that higher pH, and greater concentrations of anions and NOM are all factors, but of varying significance, in causing higher extraction in landfill and synthetic leachates than the TCLP.

  15. Electrochemical generation of oxygen. 1: The effects of anions and cations on hydrogen chemisorption and anodic oxide film formation on platinum electrode. 2: The effects of anions and cations on oxygen generation on platinum electrode

    NASA Technical Reports Server (NTRS)

    Huang, C. J.; Yeager, E.; Ogrady, W. E.

    1975-01-01

    The effects were studied of anions and cations on hydrogen chemisorption and anodic oxide film formation on Pt by linear sweep voltammetry, and on oxygen generation on Pt by potentiostatic overpotential measurement. The hydrogen chemisorption and anodic oxide film formation regions are greatly influenced by anion adsorption. In acids, the strongly bound hydrogen occurs at more cathodic potential when chloride and sulfate are present. Sulfate affects the initial phase of oxide film formation by produced fine structure while chloride retards the oxide-film formation. In alkaline solutions, both strongly and weakly bound hydrogen are influenced by iodide, cyanide, and barium and calcium cations. These ions also influence the oxide film formation. Factors considered to explain these effects are discussed. The Tafel slope for oxygen generation was found to be independent on the oxide thickness and the presence of cations or anions. The catalytic activity indicated by the exchange current density was observed decreasing with increasing oxide layer thickness, only a minor dependence on the addition of certain cations and anions was found.

  16. Competitive Deprotonation and Superoxide [O₂⁻•)] Radical-Anion Adduct Formation Reactions of Carboxamides under Negative-Ion Atmospheric-Pressure Helium-Plasma Ionization (HePI) Conditions.

    PubMed

    Hassan, Isra; Pinto, Spencer; Weisbecker, Carl; Attygalle, Athula B

    2016-03-01

    Carboxamides bearing an N-H functionality are known to undergo deprotonation under negative-ion-generating mass spectrometric conditions. Herein, we report that N-H bearing carboxamides with acidities lower than that of the hydroperoxyl radical (HO-O(•)) preferentially form superoxide radical-anion (O2(-•)) adducts, rather than deprotonate, when they are exposed to the glow discharge of a helium-plasma ionization source. For example, the spectra of N-alkylacetamides show peaks for superoxide radical-anion (O2(-•)) adducts. Conversely, more acidic amides, such as N-alkyltrifluoroacetamides, preferentially undergo deprotonation under similar experimental conditions. Upon collisional activation, the O2(-•) adducts of N-alkylacetamides either lose the neutral amide or the hydroperoxyl radical (HO-O(•)) to generate the superoxide radical-anion (m/z 32) or the deprotonated amide [m/z (M - H)(-)], respectively. For somewhat acidic carboxamides, the association between the two entities is weak. Thus, upon mildest collisional activation, the adduct dissociates to eject the superoxide anion. Superoxide-adduct formation results are useful for structure determination purposes because carboxamides devoid of a N-H functionality undergo neither deprotonation nor adduct formation under HePI conditions.

  17. Simple new method for effective concentration of 188Re solutions from alumina-based 188W-188Re generator.

    PubMed

    Guhlke, S; Beets, A L; Oetjen, K; Mirzadeh, S; Biersack, H J; Knapp, F F

    2000-07-01

    (188)Re is a useful generator-produced radioisotope currently under evaluation for a variety of therapeutic applications, including bone pain palliation and intravascular radiation therapy. Because the (188)W parent is available only in a relatively low specific activity (<0.15-0.19 GBq/mg) from reactor irradiation of enriched (186)W, relatively large volumes of 0.9% saline (>15 mL) are required for elution of the (188)Re daughter from traditional alumina-based (188)W-(188)Re generators. Because these large bolus volumes result in solutions with a relatively low specific volume activity of (188)Re (<1 GBq/mL for the 18.5-GBq generator), the availability of effective methods for eluent concentration is important. Our new approach is based on the use of 0.3 mol/L ammonium acetate as a representative salt of a weak acid instead of saline for generator elution. After generator elution, the ammonium acetate generator eluent (15-20 mL) is passed through a tandem IC-H Plus cation (Dowex-H)-anion (QMA Light) column system. Exchange of ammonium cations with hydrogen ions on the cation column forms an acetic acid solution containing perrhenate anions from which the macroscopic levels of the acetate anion of the eluent have been effectively removed. Because perrhenic acid is fully dissociated at this pH, the QMA Light column specifically traps the (188)Re-perrhenate, which is subsequently eluted with a low volume (<1 mL) of saline. Concentration ratios greater than 20:1 are readily achieved with this method. A typical clinical-scale generator loaded with 19.2 GBq (188)W was used to validate the approach. Saline elution provided (188)Re in a 75%-80% yield. Although elution with 0.15 mol/L NH4OAc gave lower yields (55%-60%), use of 0.3 mol/L NH4OAc provided yields comparable with those of saline (70%-75%). (188)W parent breakthrough was not detected after passage of the bolus through the tandem concentration system. Bolus volumes of 15-20 mL, which initially contained as much

  18. Can Fe3+ and Al3+ ions serve as cationic bridges to facilitate the adsorption of anionic As(V) species on humic acids? A density functional theory study.

    PubMed

    Gorb, Leonid; Shukla, Manoj K

    2017-03-01

    A computational chemistry investigation was undertaken to shed light on the facilitatory role played by Fe 3+ and Al 3+ cations in the adsorption of anionic As(V) species by humic acids through the formation of so-called cationic bridges. Geometric and energetic parameters were obtained using density functional theory at the B3LYP/6-31G(d,p) level in conjunction with the polarizable continuum model (to account for the influence of bulk water). We found that, despite their similar molecular geometries, the adsorption energies of the As(V) species AsO 4 3- and H 2 AsO 4- differ when Fe 3+ , FeOH 2+ , Al 3+ , and AlOH 2+ participate in the bridge. We also found that effective adsorption of As(V) species by humic acids strongly depends on whether the considered cationic bridges are tightly coordinated by humic acids at the adsorption sites, as well as on the rigidity of these humic acid adsorption sites.

  19. Effects of Hofmeister Anions on the LCST of PNIPAM as a Function of Molecular Weight

    PubMed Central

    Zhang, Yanjie; Furyk, Steven; Sagle, Laura B.; Cho, Younhee; Bergbreiter, David E.; Cremer, Paul S.

    2008-01-01

    The effect of a series of sodium salts on the lower critical solution temperature (LCST) of poly(N-isopropylacrylamide), PNIPAM, was investigated as a function of molecular weight and polymer concentration with a temperature gradient microfluidic device under a dark-field microscope. In solutions containing sufficient concentrations of kosmotropic anions, the phase transition of PNIPAM was resolved into two separate steps for higher molecular weight samples. The first step of this two step transition was found to be sensitive to the polymer’s molecular weight and solution concentration, while the second step was not. Moreover, the binding of chaotropic anions to the polymer was also influenced by molecular weight. Both sets of results could be explained by the formation of intramolecular and intermolecular hydrogen-bonding between polymer chains. By contrast, the hydrophobic hydration of the isopropyl moieties and polymer backbone was found to be unaffected by either the polymer’s molecular weight or solution concentration. PMID:18820735

  20. Influence of low concentration acid treatment on lithium disilicate core/veneer ceramic bond strength

    PubMed Central

    Garcia, Rudan P.; Conti, Paulo CR.; Pereira, Jefferson R.; Valle, Accácio Ld.

    2013-01-01

    Objective: This study evaluated the influence of low concentration acid treatment on the shear bond strength between lithium disilicate (LD) infrastructure and veneering porcelain. The surface morphology characteristic after this acid treatment was also examined. Study Design: LD reinforced ceramic cylinders (n=10) (IPS e.max Press, Ivoclar-Vivadent, Schaan, Liechtenstein) were treated (LD-treated) with a low concentration acid solution (Invex Liquid – Ivoclar-Vivadent, Schaan, Liechtenstein) or not treated with the acid solution (LD-untreated). They were veneered with a glass ceramic (IPS e.max Ceram, Ivoclar-Vivadent, Schaan, Liechtenstein). A metal ceramic group (CoCr) was tested as control. Shear bond strength (SBS) was conducted using a universal testing machine at 0.5 mm/min. Surface morphology characteristics after acid treatment were analyzed using scanning electron microscopy. Results: The acid treatment at low concentrations did not influence the SBS of the LD/veneering porcelain interface. The CoCr group showed the significant higher SBS value (35.59 ± 5.97 MPa), followed by LD-untreated group (27.76 ± 3.59 MPa) and LD-treated (27.02 ± 4.79 MPa). The fracture modes were predominantly adhesive for CoCr group and cohesive within the infrastructure for DL groups. Scanning Electron Microscopy (SEM) analysis showed no morphological differences between treated and untreated LD surfaces. Conclusions: Low concentration acid treatment did not improved SBS of veneering ceramic to LD and did not cause morphological changes on the LD surface. Key words:Lithium disilicate, glass ceramics, acid etching, shear bond strength, scanning electron microscopy. PMID:24455073

  1. Relationship between the concentrations of plasma phospholipid stearic acid and plasma lipoprotein lipids in healthy men.

    PubMed

    Li, D

    2001-01-01

    This study investigated the correlation between the plasma phospholipid (PL) saturated fatty acid (SFA) concentration (as a surrogate marker of SFA intake) and plasma lipid and lipoprotein lipid concentrations in 139 healthy Australian men aged 20-55 years old with widely varying intakes of saturated fat (vegans, n=18; ovolacto vegetarians, n=43; moderate meat eaters, n=60; high meat eaters, n=18). Both the ovolacto vegetarian and vegan groups demonstrated significant decreases in plasma total cholesterol (TC), low-density-lipoprotein cholesterol (LDL-C) and triacylglycerol concentrations compared with both the high-meat-eater and moderate-meat-eater groups. Total SFA and individual SFA [palmitic acid (16:0), stearic acid (18:0) and arachidic acid (20:0)] in the plasma PL were significantly lower in both the ovolacto vegetarian and vegan groups than in both the high- and moderate-meat-eater groups, while myristic acid (14:0) was significantly lower in the vegans than in the high-meat-eaters. Bivariate analysis of the results showed that the plasma PL stearic acid concentration was strongly positively correlated with plasma TC (P<0.0001), LDL-C (P<0.0001) and triacylglycerol (P<0.0001), with r(2) values of 0.655, 0.518 and 0.43 respectively. In multiple linear regression, after controlling for potential confounding factors (such as exercise, dietary group, age, body mass index, plasma PL myristic acid, palmitic acid and arachidic acid, and dietary total fat, saturated fat, cholesterol, carbohydrate and fibre intake), the plasma PL stearic acid concentration was still strongly positively correlated with plasma TC (P<0.0001) and LDL-C (P=0.006) concentrations. Based on the present data, it would seem appropriate for the population to reduce their dietary total SFA intake rather than to replace other SFA with stearic acid.

  2. Phenolic acids potentiate colistin-mediated killing of Acinetobacter baumannii by inducing redox imbalance.

    PubMed

    Ajiboye, Taofeek O; Skiebe, Evelyn; Wilharm, Gottfried

    2018-05-01

    Phenolic acids with catechol groups are good prooxidants because of their low redox potential. In this study, we provided data showing that phenolic acids, caffeic acid, gallic acid and protocatechuic acid, enhanced colistin-mediated bacterial death by inducing redox imbalance. The minimum inhibitory concentrations of these phenolic acids against Acinetobacter baumannii AB5075 were considerably lowered for ΔsodB and ΔkatG mutants. Checkerboard assay shows synergistic interactions between colistin and phenolic acids. The phenolic acids exacerbated colistin-induced oxidative stress in A. baumannii AB5075 through increased superoxide anion generation, NAD + /NADH and ADP/ATP ratio. In parallel, the level of reduced glutathione was significantly lowered. We conclude that phenolic acids potentiate colistin-induced oxidative stress in A. baumannii AB5075 by increasing ROS generation, energy metabolism and electron transport chain activity with a concomitant decrease in glutathione. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  3. Effect of dietary Rhodobacter capsulatus on cholesterol concentration and fatty acid composition in broiler meat.

    PubMed

    Salma, U; Miah, A G; Maki, T; Nishimura, M; Tsujii, H

    2007-09-01

    The study was designed to investigate the effects of dietary Rhodobacter capsulatus on cholesterol concentration and fatty acid composition in broiler meat. A total of 45 two-week-old male broiler chicks were randomly assigned into 3 treatment groups and fed ad libitum diets supplemented with 0 (control), 0.02, and 0.04% R. capsulatus for a 6-wk feeding period. The results of this study revealed that the supplementation of 0.04% R. capsulatus in diet reduced (P < 0.05) cholesterol and triglyceride concentrations in broiler meat. The concentrations (expressed as a percentage of total fatty acids) of oleic acid (18:1), linoleic acid (18:2), and linolenic (18:3) acid in thigh muscle and breast muscle were higher (P < 0.05) in the broilers fed the 0.04% R. capsulatus supplemented diet than in the broilers fed the control diet. The ratio of unsaturated fatty acids to saturated fatty acids was greater (P < 0.05) in both muscles of broilers fed the 0.04% R. capsulatus supplemented diet than the control diet. In addition, the concentrations of serum cholesterol and triglyceride, and hepatic cholesterol and triglyceride were also reduced (P < 0.05) by dietary R. capsulatus. Compared with the control diet, the 0.04% R. capsulatus supplemented diet reduced (P < 0.05) the ratio of low-density lipoprotein-cholesterol to high-density lipoprotein-cholesterol. Moreover, the supplementation of R. capsulatus in broiler diets did not show any adverse effect on production performance. Therefore, these results conclude that the application of R. capsulatus into diet may be feasible to reduce cholesterol concentration and improve the ratio of unsaturated fatty acids to saturated fatty acids in broiler meat.

  4. Heart Rate Response and Lactic Acid Concentration in Squash Players.

    ERIC Educational Resources Information Center

    Beaudin, Paula; And Others

    1978-01-01

    It was concluded that playing squash is an activity that results in heart rate responses of sufficient intensity to elicit aerobic training effects without producing high lactic acid concentration in the blood. (MM)

  5. A study of Lux-Flood acid-base reactions in KBr melts at 800°C

    NASA Astrophysics Data System (ADS)

    Rebrova, T. P.; Cherginets, V. L.; Ponomarenko, T. V.

    2009-11-01

    The dissociation of CO{3/2-} (p K = 2.4 ± 0.2) and precipitation of MgO (p L MgO = 10.66 ± 0.1) in a KBr melt at 800°C were studied potentiometrically with the use of a Pt(O2)|ZrO2|(Y2O3) membrane oxygen electrode. The direct calibration of the electrochemical circuit allowed only the equilibrium concentration of O2- (of strong bases) to be determined in the melt. The total concentration of oxygen-containing impurities, including CO{3/2-} and CO{4/2-} weak bases, can be found by the potentiometric titration of a sample of KBr by adding MgCl2 (Mg2+), a strong Lux-Flood acid, which causes the decomposition of these oxygen-containing anions. This reaction can also be used to remove oxo anions from alkali metal halide melts.

  6. Sensory profile, soluble sugars, organic acids, and mineral content in milk- and soy-juice based beverages.

    PubMed

    Andrés, Víctor; Tenorio, M Dolores; Villanueva, M José

    2015-04-15

    The juice industry has undergone a continuous innovation to satisfy the increasing healthy food demand by developing, among others, beverages based on fruits and milk or soybeans. The comparison among the sensory attributes between nineteen commercial mixed beverages showed significant differences in colour, sweetness, acidity, and consistency. Sucrose and citric acid were found in large proportion due to their natural presence or their addition. Potassium was the major macromineral (148-941 mg/L), especially in soy beverages. The low concentration of sodium in soy drinks is a healthy characteristic. The profile of inorganic anions has been included for the first time. Sulphate (39-278 mg/L) and phosphate (51-428 mg/L) were the predominant anions. High correlations were found between the percentage of fruit and consistency, fructose, malic acid, potassium and phosphate content (r(2)>0.790). Based on the data obtained, these beverages show pleasant organoleptic characteristics and constitute a good source of essential nutrients for regular consumers. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Synthesis and characterization of Mg-Al-layered double hydroxides intercalated with cubane-1,4-dicarboxylate anions.

    PubMed

    Rezvani, Zolfaghar; Arjomandi Rad, Farzad; Khodam, Fatemeh

    2015-01-21

    In the present work, Mg2Al-layered double hydroxide (LDH) intercalated with cubane-1,4-dicarboxylate anions was prepared from the reaction of solutions of Mg(ii) and Al(iii) nitrate salts with an alkaline solution of cubane-1,4-dicarboxylic acid by using the coprecipitation method. The successful preparation of a nanohybrid of cubane-1,4-dicarboxylate(cubane-dc) anions with LDH was confirmed by powder X-ray diffraction, FTIR spectroscopy and thermal gravimetric analysis (TGA). The increase in the basal spacing of LDHs from 8.67 Å to 13.40 Å shows that cubane-dc anions were successfully incorporated into the interlayer space. Thermogravimetric analyses confirm that the thermal stability of the intercalated cubane-dc anions is greater than that of the pure form before intercalation because of host-guest interactions involving hydrogen bonds. The interlayer structure, hydrogen bonding, and subsequent distension of LDH compounds containing cubane-dc anions were shown by molecular simulation. The RDF (radial distribution function), mean square displacement (MSD), and self-diffusion coefficient were calculated using the trajectory files on the basis of molecular dynamics (MD) simulations, and the results indicated that the cubane-dc anions were more stable when intercalated into the LDH layers. A good agreement was obtained between calculated and measured X-ray diffraction patterns and between experimental and calculated basal spacings.

  8. Nitrosamine, dimethylnitramine, and chloropicrin formation during strong base anion-exchange treatment.

    PubMed

    Kemper, Jerome M; Westerhoff, Paul; Dotson, Aaron; Mitch, William A

    2009-01-15

    Strong base anion-exchange resins represent an important option for water utilities and homeowners to address growing concerns with nitrate, arsenate, and perchlorate contamination of source waters. Most commercially available anion-exchange resins employ quaternary amine functional groups. Previous research has provided contradictory evidence regarding whether these resins serve as sources of nitrosamines, considered as highly carcinogenic nitrogenous disinfection byproducts (N-DBPs), even without disinfectants. For three common varieties of commercial anion-exchange resins, we evaluated the importance of releases of nitrosamines, and two other N-DBPs (dimethylnitramine and chloropicrin), when the resins were subjected to typical column flow conditions with and without free chlorine or chloramine application upstream or downstream of the columns. In the absence of disinfectants, fresh trimethylamine- and tributylamine-based type 1 and dimethylethanolamine-based type 2 anion-exchange resins usually released 2-10 ng/L nitrosamines, likely due to shedding of manufacturing impurities, with excursions of up to 20 ng/L following regeneration. However, the lack of significant nitrosamine release in a full-scale anion-exchange treatment system after multiple regeneration cycles indicates that releases may eventually subside. Resins also shed organic precursors that might contribute to nitrosamine formation within distribution systems when chloramines are applied downstream. With free chlorine or chloramine application upstream, nitrosamine concentrations were more significant, at 20-100 ng/L for the type 1 resins and approximately 400 ng/L for the type 2 resin. However, chloropicrin formation was lowest for the type 2 resin. Dimethylnitramine formation was significant with free chlorine application upstream but negligible with chloramines. Although no N-DBPs were detected in cation-exchange-based consumer point-of-use devices exposed to chlorinated or chloraminated waters

  9. Diel changes in metal concentrations in a geogenically acidic river: Rio Agrio, Argentina

    NASA Astrophysics Data System (ADS)

    Parker, Stephen R.; Gammons, Christopher H.; Pedrozo, Fernando L.; Wood, Scott A.

    2008-12-01

    Rio Agrio in Patagonia, Argentina is a geogenically acidic stream that derives its low-pH waters from condensation of acidic gases near its headwaters on the flanks of the active Copahue Volcano. This study reports the results of three diel (24-h) water samplings in three different pH regimes (3.2, 4.4 and 6.3) along the river. Changes in the concentration and speciation of Fe dominated the diel chemical changes at all three sites, although the timing and intensity of these cycles were different in each reach. At the two acidic sampling sites, total dissolved Fe and dissolved Fe(III) concentrations decreased during the day and increased at night, whereas dissolved Fe(II) showed the reverse pattern. These cycles are explained by Fe(III) photoreduction, as well as enhanced rates of precipitation of hydrous ferric oxide (HFO) during the warm afternoon hours. A strong correlation was observed between Fe(III) and As at the furthest upstream (pH 3.2) site, most likely due to co-precipitation of As with HFO. At the downstream (pH 6.3) location, Fe(II) concentrations increased at night, as did concentrations of rare earth elements and dissolved Al. Photoreduction does not appear to be an important process at pH 6.3, although it may be indirectly responsible for the observed diel cycle of Fe(II) due to advection of photochemically produced Fe(II) from acidic upstream waters. The results of this study of a naturally-acidic river are very similar to diel trends recently obtained from mining-impacted streams receiving acid rock drainage. The results are also used to explore the link between geochemistry and microbiology in acidic eco-systems. For example, Fe(III) photoreduction produces chemical potential energy (in the form of metastable Fe 2+) that helps support the bacterial community in this unique extreme environment.

  10. Acid neutralizing processes in an alpine watershed front range, Colorado, U.S.A.-1: Buffering capacity of dissolved organic carbon in soil solutions

    USGS Publications Warehouse

    Iggy, Litaor M.; Thurman, E.M.

    1988-01-01

    Soil interstitial waters in the Green Lakes Valley, Front Range, Colorado were studied to evaluate the capacity of the soil system to buffer acid deposition. In order to determine the contribution of humic substances to the buffering capacity of a given soil, dissolved organic carbon (DOC) and pH of the soil solutions were measured. The concentration of the organic anion, Ai-, derived from DOC at sample pH and the concentration of organic anion, Ax- at the equivalence point were calculated using carboxyl contents from isolated and purified humic material from soil solutions. Subtracting Ax- from Ai- yields the contribution of humic substances to the buffering capacity (Aequiv.-). Using this method, one can evaluate the relative contribution of inorganic and organic constituents to the acid neutralizing capacity (ANC) of the soil solutions. The relative contribution of organic acids to the overall ANC was found to be extremely important in the alpine wetland (52%) and the forest-tundra ecotone (40%), and somewhat less important in the alpine tundra sites (20%). A failure to recognize the importance of organic acids in soil solutions to the ANC will result in erroneous estimates of the buffering capacity in the alpine environment of the Front Range, Colorado. ?? 1988.

  11. Synthesis and selective IR absorption properties of iminodiacetic-acid intercalated MgAl-layered double hydroxide

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

    Wang Lijing; Xu Xiangyu; Evans, David G.

    2010-05-15

    An MgAl-NO{sub 3}-layered double hydroxide (LDH) precursor has been prepared by a method involving separate nucleation and aging steps (SNAS). Reaction with iminodiacetic acid (IDA) under weakly acidic conditions led to the replacement of the interlayer nitrate anions by iminodiacetic acid anions. The product was characterized by XRD, FT-IR, TG-DTA, ICP, elemental analysis and SEM. The results show that the original interlayer nitrate anions of LDHs precursor were replaced by iminodiacetic acid anions and that the resulting intercalation product MgAl-IDA-LDH has an ordered crystalline structure. MgAl-IDA-LDH was mixed with low density polyethylene (LDPE) using a masterbatch method. LDPE films filledmore » with MgAl-IDA-LDH showed a higher mid to far infrared absorption than films filled with MgAl-CO{sub 3}-LDH in the 7-25 {mu}m range, particularly in the key 9-11 {mu}m range required for application in agricultural plastic films. - Graphical abstract: Intercalation of iminodiacetic acid (IDA) anions in a MgAl-NO{sub 3}-layered double hydroxide host leads to an enhancement of its infrared absorbing ability for application in agricultural plastic films.« less

  12. Rheology of dilute acid hydrolyzed corn stover at high solids concentration

    Treesearch

    M.R. Ehrhardt; T.O. Monz; T.W. Root; R.K. Connelly; Tim Scott; D.J. Klingenberg

    2010-01-01

    The rheological properties of acid hydrolyzed corn stover at high solids concentration (20–35 wt.%) were investigated using torque rheometry. These materials are yield stress fluids whose rheological properties can be well represented by the Bingham model. Yield stresses increase with increasing solids concentration and decrease with increasing hydrolysis reaction...

  13. Electrodialytic extraction of anionic pharmaceutical compounds from a single drop of whole blood using a supported liquid membrane.

    PubMed

    Imoto, Yurika; Nishiyama, Hiroka; Nakamura, Yukihide; Ohira, Shin-Ichi; Toda, Kei

    2018-05-01

    A method to introduce target analytes to a chromatograph from a single drop of whole blood was investigated for minimally invasive monitoring of anionic pharmaceuticals. In this work, salicylate and loxoprofen were examined as organic anions. A micro ion extractor (MIE) has been developed for extraction of inorganic trace anions from whole blood, but this device is not suitable for extraction of pharmaceuticals. In the present study, we improved and optimized the MIE device for organic anion extraction. Various supported liquid membranes were evaluated for use as the ion transfer membrane, with each membrane placed between a droplet sample (donor) and an acceptor solution. A supported liquid membrane of porous polypropylene impregnated with 1-butanol was selected. In addition, the methods for electric field creation and electrode contact were examined to improve the characteristics of the MIE device. The current and extraction time were also optimized. With the optimized method, salicylate and loxoprofen were successfully extracted from a single drop of whole blood. Changes in the concentrations of these pharmaceuticals in blood over time were monitored after administration. As only 25μL of whole blood was required for analysis, repeat measurements could be conducted to monitor changes in the concentrations. This MIE will be useful for monitoring pharmaceutical concentrations in blood. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Influence of Bleaching on Flavor of 34% Whey Protein Concentrate and Residual Benzoic Acid Concentration in Dried Whey Proteins

    USDA-ARS?s Scientific Manuscript database

    Previous studies have shown that bleaching negatively affects the flavor of 70% whey protein concentrate (WPC70), but bleaching effects on lower-protein products have not been established. Benzoyl peroxide (BP), a whey bleaching agent, degrades to benzoic acid (BA) and may elevate BA concentrations...

  15. Influence of bleaching on flavor of 34% whey protein concentrate and residual benzoic acid concentration in dried whey products

    USDA-ARS?s Scientific Manuscript database

    Previous studies have shown that bleaching negatively affects the flavor of 70% whey protein concentrate (WPC70), but bleaching effects on lower-protein products have not been established. Benzoyl peroxide (BP), a whey bleaching agent, degrades to benzoic acid (BA) and may elevate BA concentrations...

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

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

    Wang, Lai-Sheng, E-mail: Lai-Sheng-Wang@brown.edu

    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 developmentmore » 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.« less

  17. SO2 Solvation in the 1-Ethyl-3-Methylimidazolium Thiocyanate Ionic Liquid by Incorporation into the Extended Cation-Anion Network.

    PubMed

    Firaha, Dzmitry S; Kavalchuk, Mikhail; Kirchner, Barbara

    We have carried out an ab initio molecular dynamics study on the sulfur dioxide (SO 2 ) solvation in 1-ethyl-3-methylimidazolium thiocyanate for which we have observed that both cations and anions play an essential role in the solvation of SO 2 . Whereas, the anions tend to form a thiocyanate- and much less often an isothiocyanate-SO 2 adduct, the cations create a "cage" around SO 2 with those groups of atoms that donate weak interactions like the alkyl hydrogen atoms as well as the heavy atoms of the [Formula: see text]-system. Despite these similarities between the solvation of SO 2 and CO 2 in ionic liquids, an essential difference was observed with respect to the acidic protons. Whereas CO 2 avoids accepting hydrogen bonds form the acidic hydrogen atoms of the cations, SO 2 can from O(SO 2 )-H(cation) hydrogen bonds and thus together with the strong anion-adduct it actively integrates in the hydrogen bond network of this particular ionic liquid. The fact that SO 2 acts in this way was termed a linker effect by us, because the SO 2 can be situated between cation and anion operating as a linker between them. The particular contacts are the H(cation)[Formula: see text]O(SO 2 ) hydrogen bond and a S(anion)-S(SO 2 ) sulfur bridge. Clearly, this observation provides a possible explanation for the question of why the SO 2 solubility in these ionic liquids is so high.

  18. Clinical review of delafloxacin: a novel anionic fluoroquinolone.

    PubMed

    Mogle, Bryan T; Steele, Jeffrey M; Thomas, Stephen J; Bohan, KarenBeth H; Kufel, Wesley D

    2018-06-01

    Delafloxacin is a novel anionic fluoroquinolone (FQ) approved for treatment of acute bacterial skin and skin structure infections (ABSSSIs) caused by a number of Gram-positive and Gram-negative organisms including MRSA and Pseudomonas aeruginosa. The unique chemical structure of delafloxacin renders it a weak acid and results in increased potency in acidic environments. In Phase III studies, delafloxacin had similar outcomes to comparator regimens for treatment of ABSSSIs, and was well tolerated overall. Similar to other FQs, delafloxacin is available in both intravenous and oral formulations, but differs in that delafloxacin exerts a minimal effect on cytochrome P450 enzymes and on the corrected QT interval. This novel FQ has the potential to be utilized across a wide variety of clinical settings; however, post-marketing surveillance and long-term safety and resistance data will be essential to identify optimal use scenarios.

  19. A direct ascorbate fuel cell with an anion exchange membrane

    NASA Astrophysics Data System (ADS)

    Muneeb, Omar; Do, Emily; Tran, Timothy; Boyd, Desiree; Huynh, Michelle; Ghosn, Gregory; Haan, John L.

    2017-05-01

    Ascorbic Acid (Vitamin C) is investigated as a renewable alternative fuel for alkaline direct liquid fuel cells (DLFCs). The environmentally- and biologically-friendly compound, L-ascorbic acid (AA) has been modeled and studied experimentally under acidic fuel cell conditions. In this work, we demonstrate that ascorbic acid is a more efficient fuel in alkaline media than in acidic media. An operating direct ascorbate fuel cell is constructed with the combination of L-ascorbic acid and KOH as the anode fuel, air or oxygen as the oxidant, a polymer anion exchange membrane, metal or carbon black anode materials and metal cathode catalyst. Operation of the fuel cell at 60 °C using 1 M AA and 1 M KOH as the anode fuel and electrolyte, respectively, and oxygen gas at the cathode, produces a maximum power density of 73 mW cm-2, maximum current density of 497 mA cm-2 and an open circuit voltage of 0.90 V. This performance is significantly greater than that of an ascorbic acid fuel cell with a cation exchange membrane, and it is competitive with alkaline DLFCs fueled by alcohols.

  20. Flavonoids Are Inhibitors of Human Organic Anion Transporter 1 (OAT1)–Mediated Transport

    PubMed Central

    An, Guohua; Wang, Xiaodong

    2014-01-01

    Organic anion transporter 1 (OAT1) has been reported to be involved in the nephrotoxicity of many anionic xenobiotics. As current clinically used OAT1 inhibitors are often associated with safety issues, identifying potent OAT1 inhibitors with little toxicity is of great value in reducing OAT1-mediated drug nephrotoxicity. Flavonoids are a class of polyphenolic compounds with exceptional safety records. Our objective was to evaluate the effects of 18 naturally occurring flavonoids, and some of their glycosides, on the uptake of para-aminohippuric acid (PAH) in both OAT1-expressing and OAT1-negative LLC-PK1 cells. Most flavonoid aglycones produced substantial decreases in PAH uptake in OAT1-expressing cells. Among the flavonoids screened, fisetin, luteolin, morin, and quercetin exhibited the strongest effect and produced complete inhibition of OAT1-mediated PAH uptake at a concentration of 50 μM. Further concentration-dependent studies revealed that both morin and luteolin are potent OAT1 inhibitors, with IC50 values of <0.3 and 0.47 μM, respectively. In contrast to the tested flavonoid aglycones, all flavonoid glycosides had negligible or small effects on OAT1. In addition, the role of OAT1 in the uptake of fisetin, luteolin, morin, and quercetin was investigated and fisetin was found to be a substrate of OAT1. Taken together, our results indicate that flavonoids are a novel class of OAT1 modulators. Considering the high consumption of flavonoids in the diet and in herbal products, OAT1-mediated flavonoid-drug interactions may be clinically relevant. Further investigation is warranted to evaluate the nephroprotective role of flavonoids in relation to drug-induced nephrotoxicity mediated by the OAT1 pathway. PMID:25002746

  1. Design and performance evaluation of a microfluidic ion-suppression module for anion-exchange chromatography.

    PubMed

    Wouters, Sam; Wouters, Bert; Jespers, Sander; Desmet, Gert; Eghbali, Hamed; Bruggink, Cees; Eeltink, Sebastiaan

    2014-08-15

    A microfluidic membrane suppressor has been constructed to suppress ions of alkaline mobile-phases via an acid-base reaction across a sulfonated poly(tetrafluoroethylene)-based membrane and was evaluated for anion-exchange separations using conductivity detection. The membrane was clamped between two chip substrates, accommodating rectangular microchannels for the eluent and regenerant flow, respectively. Additionally, a clamp-on chip holder has been constructed which allows the alignment and stacking of different chip modules. The response and efficacy of the microfluidic chip suppressor was assessed for a wide range of eluent (KOH) concentrations, using 127 and 183μm thick membranes, while optimizing the flow rate and concentration of the regenerant solution (H2SO4). The optimal operating eluent flow rate was determined at 5μL/min, corresponding to the optimal van-Deemter flow velocity of commercially-available column technology, i.e. a 0.4mm i.d.×250mm long column packed with 7.5μm anion-exchange particles. When equilibrated at 10mM KOH, a 99% decrease in conductivity signal could be obtained within 5min when applying 10mM H2SO4 regenerant at 75μL/min. A background signal as low as 1.2μS/cm was obtained, which equals the performance of a commercially-available electrolytic hollow-fiber suppressor. When increasing the temperature of the membrane suppressor from 15 to 20°C, ion suppression was significantly improved allowing the application of 75mM KOH. The applicability of the chip suppressor has been demonstrated with an isocratic baseline separation of a mixture of seven inorganic ions, yielding plate numbers between 5300 and 10,600 and with a gradient separation of a complex ion mixture. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Removal of fluorescent dissolved organic matter in biologically treated textile effluents by NDMP anion exchange process: efficiency and mechanism.

    PubMed

    Li, Wen-Tao; Xu, Zi-Xiao; Shuang, Chen-Dong; Zhou, Qing; Li, Hai-Bo; Li, Ai-Min

    2016-03-01

    The efficiency and mechanism of anion exchange resin Nanda Magnetic Polymer (NDMP) for removal of fluorescent dissolved organic matter in biologically treated textile effluents were studied. The bench-scale experiments showed that as well as activated carbon, anion exchange resin could efficiently remove both aniline-like and humic-like fluorescent components, which can be up to 40 % of dissolved organic matter. The humic-like fluorescent component HS-Em460-Ex3 was more hydrophilic than HS-Em430-Ex2 and contained fewer alkyl chains but more acid groups. As a result, HS-Em460-Ex3 was eliminated more preferentially by NDMP anion exchange. However, compared with adsorption resins, the polarity of fluorescent components had a relatively small effect on the performance of anion exchange resin. The long-term pilot-scale experiments showed that the NDMP anion exchange process could remove approximately 30 % of the chemical oxygen demand and about 90 % of color from the biologically treated textile effluents. Once the issue of waste brine from resin desorption is solved, the NDMP anion exchange process could be a promising alternative for the advanced treatment of textile effluents.

  3. Covalent Polymers Containing Discrete Heterocyclic Anion Receptors

    PubMed Central

    Rambo, Brett M.; Silver, Eric S.; Bielawski, Christopher W.; Sessler, Jonathan L.

    2010-01-01

    This chapter covers recent advances in the development of polymeric materials containing discrete heterocyclic anion receptors, and focuses on advances in anion binding and chemosensor chemistry. The development of polymers specific for anionic species is a relatively new and flourishing area of materials chemistry. The incorporation of heterocyclic receptors capable of complexing anions through non-covalent interactions (e.g., hydrogen bonding and electrostatic interactions) provides a route to not only sensitive but also selective polymer materials. Furthermore, these systems have been utilized in the development of polymers capable of extracting anionic species from aqueous environments. These latter materials may lead to advances in water purification and treatment of diseases resulting from surplus ions. PMID:20871791

  4. Pitting corrosion of titanium. The relationship between pitting potential and competitive anion adsorption at the oxide film/electrolyte interface

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

    Basame, S.B.; White, H.S.

    2000-04-01

    The potential-dependent breakdown of the native oxide film ({approximately}20 {angstrom} thick) on titanium has been investigated in aqueous Br{sup {minus}} solutions and in solutions that contain a mixture of Br{sup {minus}} and anions that inhibit oxide breakdown (i.e., Cl{sup {minus}}, I{sup {minus}}, SO{sub 4}{sup 2{minus}}, Fe(CN){sub 6}{sup 4{minus}}, and Fe(CN){sub 6}{sup 3{minus}}). The oxide film is unstable in neutral pH solutions containing only Br{sup {minus}}, resulting in the formation of stable corrosion pits at relatively low potentials ({approximately}1.4 V vs. Ag/AgCl). The pitting potential, E{sub p}, is strongly dependent upon the concentration of Br{sup {minus}}, and can be modeled usingmore » a Langmuir isotherm to describe the adsorption of Br{sup {minus}} at the oxide film/electrolyte interface. Addition of a second anion inhibits oxide film breakdown, as indicated by a large positive shift in E{sub p} and a decrease in the number of stable corrosion pits. The dependence of E{sub p} on the relative concentrations of Br{sup {minus}} and the inhibitor anion is consistent with competitive adsorption of the anions. Equilibrium adsorption coefficients for I{sup {minus}}, Br{sup {minus}}, and Cl{sup {minus}} are estimated from the dependence of E{sub p} on anion concentration. The results are used to establish a physical basis for the anomalously low pitting potential for titanium in aqueous Br{sup {minus}} solutions.« less

  5. Solvation of the fluorine containing anions and their lithium salts in propylene carbonate and dimethoxyethane.

    PubMed

    Chaban, Vitaly

    2015-07-01

    Electrolyte solutions based on the propylene carbonate (PC)-dimethoxyethane (DME) mixtures are of significant importance and urgency due to emergence of lithium-ion batteries. Solvation and coordination of the lithium cation in these systems have been recently attended in detail. However, analogous information concerning anions (tetrafluoroborate, hexafluorophosphate) is still missed. This work reports PM7-MD simulations (electronic-structure level of description) to include finite-temperature effects on the anion solvation regularities in the PC-DME mixture. The reported result evidences that the anions appear weakly solvated. This observation is linked to the absence of suitable coordination sites in the solvent molecules. In the concentrated electrolyte solutions, both BF4(-) and PF6(-) prefer to exist as neutral ion pairs (LiBF4, LiPF6).

  6. Predictions of diagenetic reactions in the presence of organic acids

    NASA Astrophysics Data System (ADS)

    Harrison, Wendy J.; Thyne, Geoffrey D.

    1992-02-01

    Stability constants have been estimated for cation complexes with anions of monofunctional and difunctional acids (combinations of Ca, Mg, Fe, Al, Sr, Mn, U, Th, Pb, Cu, Zn with formate, acetate, propionate, oxalate, malonate, succinate, and salicylate) between 0 and 200°C. Difunctional acid anions form much more stable complexes than monofunctional acid anions with aluminum; the importance of the aluminum-acetate complex is relatively minor in comparison to aluminum oxalate and malonate complexes. Divalent metal cations such as Mg, Ca, and Fe form more stable complexes with acetate than with difunctional acid anions. Aluminum-oxalate can dominate the species distribution of aluminum under acidic pH conditions, whereas the divalent cation-acetate and oxalate complexes rarely account for more than 60% of the total dissolved cation, and then only in more alkaline waters. Mineral thermodynamic affinities were calculated using the reaction path model EQ3/6 for waters having variable organic acid anion (OAA) contents under conditions representative of those found during normal burial diagenesis. The following scenarios are possible: 1) K-feldspar and albite are stable, anorthite dissolves 2) All feldpars are stable 3) Carbonates can be very unstable to slightly unstable, but never increase in stability. Organic acid anions are ineffective at neutral to alkaline pH in modifying stabilities of aluminosilicate minerals whereas the anions are variably effective under a wide range of pH in modifying carbonate mineral stabilities. Reaction path calculations demonstrate that the sequence of mineral reactions occurring in an arkosic sandstone-fluid system is only slightly modified by the presence of OAA. A spectrum of possible sandstone alteration mineralogies can be obtained depending on the selected boundary conditions: EQ3/6 predictions include quartz overgrowth, calcite replacement of plagioclase, albitization of plagioclase, and the formation of porosity-occluding calcite

  7. Geochemical Modeling of Reactions and Partitioning of Trace Metals and Radionuclides during Titration of Contaminated Acidic Sediments

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

    Zhang, Fan; Parker, Jack C.; Luo, Wensui

    2008-01-01

    Many geochemical reactions that control aqueous metal concentrations are directly affected by solution pH. However, changes in solution pH are strongly buffered by various aqueous phase and solid phase precipitation/dissolution and adsorption/desorption reactions. The ability to predict acid-base behavior of the soil-solution system is thus critical to predict metal transport under variable pH conditions. This study was undertaken to develop a practical generic geochemical modeling approach to predict aqueous and solid phase concentrations of metals and anions during conditions of acid or base additions. The method of Spalding and Spalding was utilized to model soil buffer capacity and pH-dependent cationmore » exchange capacity by treating aquifer solids as a polyprotic acid. To simulate the dynamic and pH-dependent anion exchange capacity, the aquifer solids were simultaneously treated as a polyprotic base controlled by mineral precipitation/dissolution reactions. An equilibrium reaction model that describes aqueous complexation, precipitation, sorption and soil buffering with pH-dependent ion exchange was developed using HydroGeoChem v5.0 (HGC5). Comparison of model results with experimental titration data of pH, Al, Ca, Mg, Sr, Mn, Ni, Co, and SO{sub 4}{sup 2-} for contaminated sediments indicated close agreement, suggesting that the model could potentially be used to predict the acid-base behavior of the sediment-solution system under variable pH conditions.« less

  8. Suitable Concentrations of Uric Acid Can Reduce Cell Death in Models of OGD and Cerebral Ischemia-Reperfusion Injury.

    PubMed

    Zhang, Bin; Yang, Ning; Lin, Shao-Peng; Zhang, Feng

    2017-07-01

    Cerebral infarction (CI) is a common clinical cerebrovascular disease, and to explore the pathophysiological mechanisms and seek effective treatment means are the hotspot and difficult point in medical research nowadays. Numerous studies have confirmed that uric acid plays an important role in CI, but the mechanism has not yet been clarified. When treating HT22 and BV-2 cells with different concentrations of uric acid, uric acid below 450 μM does not have significant effect on cell viability, but uric acid more than 500 μM can significantly inhibit cell viability. After establishing models of OGD (oxygen-glucose deprivation) with HT22 and BV-2 cells, uric acid at a low concentration (50 μM) cannot improve cell viability and apoptosis, and Reactive oxygen species (ROS) levels during OGD/reoxygenation; a suitable concentration (300 μM) of uric acid can significantly improve cell viability and apoptosis, and reduce ROS production during OGD/reoxygenation; but a high concentration (1000 μM) of uric acid can further reduce cell viability and enhance ROS production. After establishing middle cerebral artery occlusion of male rats with suture method, damage and increase of ROS production in brain tissue could be seen, and after adding suitable concentration of uric acid, the degree of brain damage and ROS production was reduced. Therefore, different concentrations of uric acid should have different effect, and suitable concentrations of uric acid have neuroprotective effect, and this finding may provide guidance for study on the clinical curative effect of uric acid.

  9. Interfacial activity in alkaline flooding enhanced oil recovery

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

    Chan, M.K.

    1981-01-01

    The ionization of long-chained organic acids in the crude oil to form soaps was shown to be primarily responsible for the lowering of oil-water interfacial tension at alkaline pH. These active acids can be concentrated by silica gel chromatography into a minor polar fraction. An equilibrium chemical model was proposed based on 2 competing reactions: the ionization of acids to form active anions, and the formation of undissociated soap between acid anions and sodium ions. It correlates the interfacial activity with the interfacial concentration of active acid anions which is expressed in terms of the concentrations of the chemical speciesmore » in the system. The model successfully predicts the observed oil-alkaline solution interfacial phenomenon, including its dependence on pH, alkali and salt concentrations, type of acid present and type of soap formed. Flooding at different alkali concentrations to activate different acid species present in the crude was shown to give better recovery than flooding at a single high alkali concentration. Treating the crude oil with a dilute solution of mineral acids liberates additional free active acids and yields better interfacial activity during subsequent alkali contact.« less

  10. Effect of sulfuric acid concentration of bentonite and calcination time of pillared bentonite

    NASA Astrophysics Data System (ADS)

    Mara, Ady; Wijaya, Karna; Trisunaryati, Wega; Mudasir

    2016-04-01

    An activation of natural clay has been developed. Activation was applied by refluxing the natural bentonite in variation of the sulfuric acid concentration and calcination time of pillared bentonite (PLC). Calcination was applied using oven in microwave 2,45 GHz. Determination of acidity was applied by measuring the amount of adsorbed ammonia and pyridine. Morphological, functional groups and chrystanility characterizations were analyzed using SEM, TEM, FTIR and XRD. Porosity was analyzed using SSA. The results showed that the greater of the concentration of sulfuric acid and calcination time was, the greater the acidity of bentonite as well as the pore diameter were. FTIR spectra showed no fundamental changes in the structure of the natural bentonite, SEM, and TEM images were showing an increase in space or field due to pillarization while the XRD patterns showed a shift to a lower peak. Optimization was obtained at a concentration of 2 M of sulfuric acid and calcination time of 20 minutes, keggin ion of 2.2 and suspension of 10 mmol, respectively each amounted to 11.7490 mmol/gram of ammonia and 2.4437 mmol/gram of pyridine with 154.6391 m2/gram for surface area, 0.130470 m3/gram of pore volume and 3.37484 nm of pore diameter.

  11. Volatile aromatic hydrocarbons and dicarboxylic acid concentrations in air at an urban site in the Southwestern US

    NASA Astrophysics Data System (ADS)

    Tran, Ngoc K.; Steinberg, Spencer M.; Johnson, Brian J.

    Concentrations of benzene, toluene, ethylbenzene, o-xylene, and m- and p-xylene were measured at an urban sampling site in Las Vegas, NV by sorbent sampling followed by thermal desorption and determination by GC-PID. Simultaneously, measurements of oxalic, malonic, succinic, and adipic acids were made at the same site by collection on quartz filters, extraction, esterification, and determination by GC-FID. For the period from April 7, 1997 to June 11, 1997, 201 sets of hydrocarbon measurements and 99 sets of acid measurements were made. Additional measurements of dicarboxylic acids were made on samples that represented potential direct sources, e.g. green plants and road dust. Correlations between the hydrocarbon and CO concentrations (measured by the Clark County Health District at a nearby site) were highly significant and a strong negative correlation of hydrocarbon concentration with ozone concentration (also from the county site) was observed under quiescent atmospheric conditions. In general, dicarboxylic acid concentrations were well correlated with one another (with the exception of adipic acid) but not well correlated with hydrocarbon, CO, and ozone concentrations. Multiple sources and complex formation processes are indicated for the dicarboxylic acids.

  12. An experimental and modeling study of humic acid concentration effect on H(+) binding: Application of the NICA-Donnan model.

    PubMed

    Vidali, Roza; Remoundaki, Emmanouela; Tsezos, Marios

    2009-11-15

    Humic substances are the most abundant components of the colloidal and the dissolved fraction of natural organic matter (NOM) and they are characterized by a strong binding capacity for both metals and organic pollutants, affecting their mobility and bioavailability. The understanding of the humic acidic character is the first necessary step for the study of the mechanisms of binding of other positively charged soluble metal species by humic molecules. The present work, which constitutes part of the Ph.D. thesis of Roza Vidali, reports results on the influence of the concentration of humic acids on the binding of protons obtained through both an experimental and a modeling approach. A reference purified peat humic acid (PPHA) isolated by the International Humic Substances Society (IHSS) and a humic acid from a Greek soil (GHA) were experimentally studied at various humic acid concentrations, ranging from 20 to 200mgL(-1). The proton binding isotherms obtained at different humic acid concentrations have shown that proton binding is dependent on the concentration of both humic acids. Proton binding experimental data were fitted to the NICA-Donnan model and the model parameter values were calculated for humic acid concentrations of 20 and >or=100mgL(-1). The results obtained for the NICA-Donnan parameters at humic acid concentrations >or=100mgL(-1) are in excellent agreement with those reported in the literature. However, these model parameter values cannot be used for modeling and predicting cation binding in natural aquatic systems, where humic acid concentrations are much lower. Two sets of the NICA-Donnan parameters are reported: one for humic acid concentrations of >or=100mgL(-1) and one for humic acid concentration of 20mgL(-1). The significance of the parameters values for each concentration level is also discussed.

  13. Organic anion exudation by ectomycorrhizal fungi and Pinus sylvestris in response to nutrient deficiencies.

    PubMed

    van Schöll, Laura; Hoffland, Ellis; van Breemen, Nico

    2006-01-01

    Low molecular weight organic anions (LMWOA) can enhance weathering of mineral grains. We tested the hypothesis that ectomycorrhizal (EcM) fungi and tree seedlings increase their exudation of LMWOA when supply of magnesium, potassium and phosphorus is low to enhance the mobilization of Mg, K and P from mineral grains. Ectomycorrhizal fungi and Pinus sylvestris seedlings were cultured in symbiosis and in isolation on glass beads with nutrient solution or with sand as a rooting medium, with a complete nutrient supply or with Mg, K, P or N in low supply. Concentrations of all dicarboxylic LMWOA in the rooting medium were measured. Nonmycorrhizal seedlings released predominantly malonate. Colonization with Hebeloma longicaudum decreased the amount of organic anions exuded, whereas Paxillus involutus and Piloderma croceum increased the concentration of oxalate but not the total amount of LMWOA. Phosphorus deficiency increased the concentration of LMWOA by nonmycorrhizal and EcM seedlings. Magnesium deficiency increased the concentration of oxalate by nonmycorrhizal and EcM seedlings, but not the concentration of total LMWOA. Paxillus involutus grown in pure culture responded differently to low nutrient supply compared with symbiotic growth. Ectomycorrhizal fungi did not increase the total concentration of LMWOA compared with nonmycorrhizal seedlings but, depending on the fungal species, they affected the type of LMWOA found.

  14. High extracellular concentration of excitatory amino acids glutamate and aspartate in human brain abscess.

    PubMed

    Dahlberg, Daniel; Ivanovic, Jugoslav; Hassel, Bjørnar

    2014-04-01

    Brain abscesses often cause symptoms of brain dysfunction, including seizures, suggesting interference with normal neurotransmission. We determined the concentration of extracellular neuroactive amino acids in brain abscesses from 16 human patients. Glutamate was present at 3.6 mmol/L (median value, range 0.5-10.8), aspartate at 1.0 mmol/L (range 0.09-6.8). For comparison, in cerebroventricular fluid glutamate was ∼0.6 μmol/L, and aspartate was not different from zero. The total concentration of amino acids was higher in eight patients with seizures: 66 mmol/L (median value, range 19-109) vs. 21 mmol/L (range 4-52) in eight patients without seizures (p=0.026). The concentration of aspartate and essential amino acids tryptophan, phenylalanine, tyrosine, leucine, and isoleucine was higher in pus from patients with seizures (p⩽0.040), whereas that of glutamate was not (p=0.095). The median concentration of the non-proteinogenic, inhibitory amino acid taurine was similar in the two groups, 0.7-0.8 mmol/L (range 0.1-6.1). GABA could not be detected in pus. The patient groups did not differ with respect to abscess volume, the cerebral lobe affected, age, or time from symptom onset to surgery. Seven patients with extracerebral, intracranial abscesses had significantly lower pus concentration of glutamate (352 μmol/L, range 83-1368) and aspartate (71 μmol/L, range 22-330) than intracerebral abscesses (p<0.001). We conclude that excitatory amino acids glutamate and aspartate may reach very high concentrations in brain abscesses, probably contributing to symptoms through activation of glutamate receptors in the surrounding brain tissue. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. The benzil-cyanide reaction and its application to the development of a selective cyanide anion indicator.

    PubMed

    Cho, Dong-Gyu; Kim, Jong Hoon; Sessler, Jonathan L

    2008-09-10

    The benzil-cyanide reaction is a cyanide-specific reaction that has been exploited to produce a colorimetric indicator for this toxic anion. This was done by producing a pi-extended analogue of benzil, 7, which is soluble in a 70:30 (v/v) mixture of methanol-water. In this medium, dilute solutions of 7 are yellow but produce colorless products when exposed to low concentrations of cyanide anion (> or = 1.7 microM; added as an aqueous NaCN solution), but no other common anions (e.g., OH(-), F(-), N3(-), benzoate(-), and H2PO4(-)). On the basis of these observations and supporting mechanistic analyses, it is concluded that the modified benzil system 7 is a promising cyanide anion indicator that is attractive in terms of its selectivity, ease-of-use, water compatibility, and the low, naked-eye discernible cyanide detection limit it provides.

  16. Changes in relative and absolute concentrations of plasma phospholipid fatty acids observed in a randomized trial of Omega-3 fatty acids supplementation in Uganda.

    PubMed

    Song, Xiaoling; Diep, Pho; Schenk, Jeannette M; Casper, Corey; Orem, Jackson; Makhoul, Zeina; Lampe, Johanna W; Neuhouser, Marian L

    2016-11-01

    Expressing circulating phospholipid fatty acids (PLFAs) in relative concentrations has some limitations: the total of all fatty acids are summed to 100%; therefore, the values of individual fatty acid are not independent. In this study we examined if both relative and absolute metrics could effectively measure changes in circulating PLFA concentrations in an intervention trial. 66 HIV and HHV8 infected patients in Uganda were randomized to take 3g/d of either long-chain omega-3 fatty acids (1856mg EPA and 1232mg DHA) or high-oleic safflower oil in a 12-week double-blind trial. Plasma samples were collected at baseline and end of trial. Relative weight percentage and absolute concentrations of 41 plasma PLFAs were measured using gas chromatography. Total cholesterol was also measured. Intervention-effect changes in concentrations were calculated as differences between end of 12-week trial and baseline. Pearson correlations of relative and absolute concentration changes in individual PLFAs were high (>0.6) for 37 of the 41 PLFAs analyzed. In the intervention arm, 17 PLFAs changed significantly in relative concentration and 16 in absolute concentration, 15 of which were identical. Absolute concentration of total PLFAs decreased 95.1mg/L (95% CI: 26.0, 164.2; P=0.0085), but total cholesterol did not change significantly in the intervention arm. No significant change was observed in any of the measurements in the placebo arm. Both relative weight percentage and absolute concentrations could effectively measure changes in plasma PLFA concentrations. EPA and DHA supplementation changes the concentrations of multiple plasma PLFAs besides EPA and DHA.Both relative weight percentage and absolute concentrations could effectively measure changes in plasma phospholipid fatty acid (PLFA) concentrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Effective charge measurements reveal selective and preferential accumulation of anions, but not cations, at the protein surface in dilute salt solutions

    PubMed Central

    Gokarn, Yatin R; Fesinmeyer, R Matthew; Saluja, Atul; Razinkov, Vladimir; Chase, Susan F; Laue, Thomas M; Brems, David N

    2011-01-01

    Specific-ion effects are ubiquitous in nature; however, their underlying mechanisms remain elusive. Although Hofmeister-ion effects on proteins are observed at higher (>0.3M) salt concentrations, in dilute (<0.1M) salt solutions nonspecific electrostatic screening is considered to be dominant. Here, using effective charge (Q*) measurements of hen-egg white lysozyme (HEWL) as a direct and differential measure of ion-association, we experimentally show that anions selectively and preferentially accumulate at the protein surface even at low (<100 mM) salt concentrations. At a given ion normality (50 mN), the HEWL Q* was dependent on anion, but not cation (Li+, Na+, K+, Rb+, Cs+, GdnH+, and Ca2+), identity. The Q* decreased in the order F− > Cl− > Br− > NO3− ∼ I− > SCN− > ClO4− ≫ SO42−, demonstrating progressively greater binding of the monovalent anions to HEWL and also show that the SO42− anion, despite being strongly hydrated, interacts directly with the HEWL surface. Under our experimental conditions, we observe a remarkable asymmetry between anions and cations in their interactions with the HEWL surface. PMID:21432935

  18. Process for removing sulfate anions from waste water

    DOEpatents

    Nilsen, David N.; Galvan, Gloria J.; Hundley, Gary L.; Wright, John B.

    1997-01-01

    A liquid emulsion membrane process for removing sulfate anions from waste water is disclosed. The liquid emulsion membrane process includes the steps of: (a) providing a liquid emulsion formed from an aqueous strip solution and an organic phase that contains an extractant capable of removing sulfate anions from waste water; (b) dispersing the liquid emulsion in globule form into a quantity of waste water containing sulfate anions to allow the organic phase in each globule of the emulsion to extract and absorb sulfate anions from the waste water and (c) separating the emulsion including its organic phase and absorbed sulfate anions from the waste water to provide waste water containing substantially no sulfate anions.

  19. Uric acid concentrations are associated with insulin resistance and birthweight in normotensive pregnant women.

    PubMed

    Laughon, S Katherine; Catov, Janet; Roberts, James M

    2009-12-01

    We sought to investigate whether uric acid concentrations are increased in pregnant women with insulin resistance and to correlate both with fetal growth. Uric acid, glucose, and insulin were measured in plasma at 20.4 (+/-2.0) weeks' gestation in 263 women. The association between uric acid and insulin resistance, as estimated using the homeostasis model assessment (HOMA), was analyzed and related to birthweights. In 212 (80.6%) women who remained normotensive throughout pregnancy, HOMA increased 1.23 U per 1-mg/dL increase in uric acid (95% confidence interval, 1.07-1.42; P=.003). Infants born to normotensive women in the upper quartile of uric acid and lowest HOMA quartile weighed 435.6 g less than infants of women with highest uric acid and HOMA quartiles (P<.005). Increasing uric acid concentrations were associated with insulin resistance in midpregnancy. Hyperuricemia was associated with lower birthweight in normotensive women, and this effect was attenuated by insulin resistance.

  20. The concentration of free amino acids in blood serum of dairy cows with primary ketosis.

    PubMed

    Marczuk, J; Brodzki, P; Brodzki, A; Kurek, Ł

    2018-03-01

    Ketosis is a common condition found in the initial stages of lactation in high-yielding dairy cows. The major cause of ketosis is a negative energy balance. During the energy deficiency, proteolysis processes develop parallel to lipolysis. During proteolysis, muscle tissue can be used as a source of amino acid. To date, the participation of amino acids in gluconeogenesis (glucogenic amino acids) and ketogenesis (ketogenic amino acids) has not been determined in detail. This paper presents the study on determination of the parameters of protein and free amino acid metabolism in blood serum of dairy cows with primary ketosis compared to healthy cows. This study contributes to better understanding of the role of amino acids in pathogenesis of ketosis. A total of 30 cows, divided into two groups: experimental (15 cows with ketosis) and control (15 healthy cows), were included in the study. The concentrations of glucose, β-hydroxybutyrate, total protein, albumin, urea, and free amino acids were determined in peripheral blood. Statistically significantly higher concentrations of glutamine, glutamic acid, isoleucine (p≤0.001), and tyrosine (p≤0.05) were found in cows with primary ketosis compared to healthy cows. Significant decrease in the concentrations of asparagine, histidine, methionine, and serine (p≤0.001), alanine, leucine, lysine and proline (p≤0.05) was observed. Significant increase of total ketogenic and glucogenic amino acids (p≤0.05), and an increased ratio of total ketogenic and glucogenic amino acids to total amino acids (p≤0.001) were noted in cows with ketosis. In our study, the changes, in particular observed in amino acid concentration in cows with primary ketosis, indicate its intensive use in both ketogenesis and gluconeogenesis processes. Therefore, a detailed understanding of the role that amino acids play in gluconeogenesis and ketogenesis will improve ketosis diagnostics and monitoring the course of a ketosis episode. Perhaps, the

  1. The desert plant Phoenix dactylifera closes stomata via nitrate-regulated SLAC1 anion channel.

    PubMed

    Müller, Heike M; Schäfer, Nadine; Bauer, Hubert; Geiger, Dietmar; Lautner, Silke; Fromm, Jörg; Riederer, Markus; Bueno, Amauri; Nussbaumer, Thomas; Mayer, Klaus; Alquraishi, Saleh A; Alfarhan, Ahmed H; Neher, Erwin; Al-Rasheid, Khaled A S; Ache, Peter; Hedrich, Rainer

    2017-10-01

    Date palm Phoenix dactylifera is a desert crop well adapted to survive and produce fruits under extreme drought and heat. How are palms under such harsh environmental conditions able to limit transpirational water loss? Here, we analysed the cuticular waxes, stomata structure and function, and molecular biology of guard cells from P. dactylifera. To understand the stomatal response to the water stress phytohormone of the desert plant, we cloned the major elements necessary for guard cell fast abscisic acid (ABA) signalling and reconstituted this ABA signalosome in Xenopus oocytes. The PhoenixSLAC1-type anion channel is regulated by ABA kinase PdOST1. Energy-dispersive X-ray analysis (EDXA) demonstrated that date palm guard cells release chloride during stomatal closure. However, in Cl - medium, PdOST1 did not activate the desert plant anion channel PdSLAC1 per se. Only when nitrate was present at the extracellular face of the anion channel did the OST1-gated PdSLAC1 open, thus enabling chloride release. In the presence of nitrate, ABA enhanced and accelerated stomatal closure. Our findings indicate that, in date palm, the guard cell osmotic motor driving stomatal closure uses nitrate as the signal to open the major anion channel SLAC1. This initiates guard cell depolarization and the release of anions together with potassium. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  2. [Effects of elevated ozone concentrations on enzyme activities and organic acids content in wheat rhizospheric soil.

    PubMed

    Yin, Wei Qin; Jing, Hao Qi; Wang, Ya Bo; Wei, Si Yu; Sun, Yue; Wang, Sheng Sen; Wang, Xuai Zhi

    2018-02-01

    The elevated concentration of tropospheric ozone (O 3 ) is an important global climate change driver, with adverse impacts on soil ecological environment and crop growth. In this study, a pot experiment was carried out in an open top chamber (OTC), to investigate the effects of elevated ozone concentration on soil enzyme activities (catalase, polyphenol oxidase, dehydrogenase and invertase), organic acids contents (oxalic acid, citric acid and malic acid) at different growth stages (tillering, jointing, heading and ripening stages) of wheat, and combined with the rhizospheric soil physicochemical properties and plant root characteristics to analyze the underlying reasons. The results showed that, elevated ozone concentration increased soil catalase, polyphenol oxidase, dehydrogenase and invertase activities at wheat ripening period to different degrees, with the effects on the activities of catalase and polyphenol oxidase being statistically significant. At the heading stage, activities of dehydrogenase and invertase were significantly increased by up to 76.7%. At the ripening stage, elevated ozone concentration significantly increased the content of citric acid and malic acid and redox potential (Eh) in rhizospheric soil, but reduced soil pH, electrical conductivity, total carbon and nitrogen. For root characteristics, elevated ozone concentrations significantly reduced the wheat root biomass, total root length and root surface area but increased the average root diameter.

  3. Perfluoroalkyl Acid Concentrations in Livers of Fox (Vulpes vulpes) and Chamois (Rupicapra rupicapra) from Germany and Austria.

    PubMed

    Riebe, Rika Alessa; Falk, Sandy; Georgii, Sebastian; Brunn, Hubertus; Failing, Klaus; Stahl, Thorsten

    2016-07-01

    The concentrations of 11 perfluorinated alkyl acids (PFAAs) were measured in the livers of foxes (Vulpes vulpes) from Germany, a primarily carnivorous species, and chamois (Rupicapra rupicapra) from Austria, an herbivorous species. Perfluorooctanesulfonate (PFOS) at concentrations [all results refer to wet weight (ww)] of 3.2-320 µg/kg were detected in all 40 fox livers tested, yielding an arithmetic mean of 46.6 µg/kg and a median of 29.8 µg/kg. Long-chain PFAAs were detected at concentrations of 1.7 µg/kg perfluorononanoic acid (PFNA) to 2.4 µg/kg perfluorodecanoic acid (PFDA) and perfluorododecanoic acid (PFDoDA). Of the short-chain PFAAs tested, only perfluorohexanoic acid (PFHxA) was found in 1 fox liver at a concentration of 1.4 µg/kg, and perfluorohexane sulfonate (PFHxS) was found in 2 fox livers at a concentration of 1 µg/kg each. PFOS and PFNA concentrations higher than limit of quantification (LOQ) were detected in 90.9 and 81.8 % of chamois livers, respectively. The arithmetic mean for PFOS concentrations was 2.2 µg/kg (median 2.4 µg/kg), a factor of 21 (median factor of 12) lower than in fox livers. The arithmetic mean for PFNA concentrations was 2.0 µg/kg (median 1.9 µg/kg). Perfluorobutanoic acid, PFHxA, perfluorooctanoic acid, perfluorobutanesulfonate, and PFHxS were not detected at concentrations higher than the LOQ in any of the samples. The various results are compared with one another and with the results of other studies of herbivorous, carnivorous, and omnivorous wild animals. The highest concentrations of PFAA, in particular PFOS, were found in omnivorous animals followed by carnivores. The lowest levels were present in herbivores.

  4. Stabilization of diketo tautomer of curcumin by premicellar anionic surfactants: UV-Visible, fluorescence, tensiometric and TD-DFT evidences

    NASA Astrophysics Data System (ADS)

    Dutta, Anisha; Boruah, Bornali; Manna, Arun K.; Gohain, Biren; Saikia, Palash M.; Dutta, Robin K.

    2013-03-01

    A newly observed UV band of aqueous curcumin, a biologically important molecule, in presence of anionic surfactants, viz., sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), and sodium dodecylsulfonate (SDSN) in buffered aqueous solutions has been studied experimentally and theoretically. The 425 nm absorption band of curcumin disappears and a new UV-band is observed at 355 nm on addition of the surfactants in the submicellar concentration range which is reversed as the surfactant concentration approaches the critical micelle concentration (CMC). The observed spectral absorption, fluorescence intensity and surface tension behavior, under optimal experimental conditions of submicellar concentration ranges of the surfactants in the pH range of 2.00-7.00, indicate that the new band is due to the β-diketo tautomer of curcumin stabilized by interactions between curcumin and the anionic surfactants. The stabilization of the diketo tautomer by submicellar anionic surfactants described here as well as by submicellar cationic surfactant, reported recently, is unique as this is the only such behavior observed in presence of submicellar surfactants of both charge types. The experimental results are in good agreement with the theoretical calculations using ab initio density functional theory combined with time dependent density functional theory (TD-DFT) calculations.

  5. Lymphatic trafficking kinetics and near-infrared imaging using star polymer architectures with controlled anionic character

    PubMed Central

    Bagby, Taryn R.; Cai, Shuang; Duan, Shaofeng; Yang, Qiuhong; Thati, Sharadvi; Berkland, Cory; Aires, Daniel J.; Forrest, M. Laird

    2015-01-01

    Targeted lymphatic delivery of nanoparticles for drug delivery and imaging is primarily dependent on size and charge. Prior studies have observed increased lymphatic uptake and retentions of over 48 hrs for negatively charged particles compared to neutral and positively charged particles. We have developed new polymeric materials that extend retention over a more pharmaceutically relevant 7-day period. We used whole body fluorescence imaging to observe in mice the lymphatic trafficking of a series of anionic star poly-(6-O-methacryloyl-D-galactose) polymer-NIR dye (IR820) conjugates. The anionic charge of polymers was increased by modifying galactose moieties in the star polymers with succinic anhydride. Increasing anionic nature was associated with enhanced lymphatic uptake up to a zeta potential of ca. -40 mV; further negative charge did not affect lymphatic uptake. Compared to the 20% acid-conjugate, the 40 to 90% acid-star-polymer conjugates exhibited a 2.5- to 3.5-fold increase in lymphatic uptake in both the popliteal and iliac nodes. The polymer conjugates exhibited node half-lives of 2 to 20 hrs in the popliteal nodes and 19 to 114 hrs in the deeper iliac nodes. These polymer conjugates can deliver drugs or imaging agents with rapid lymphatic uptake and prolonged deep-nodal retention; thus they may provide a useful vehicle for sustained intralymphatic drug delivery with low toxicity. PMID:22546180

  6. Background of the Hammett equation as observed for isolated molecules: meta- and para-substituted benzoic acids.

    PubMed

    Exner, Otto; Böhm, Stanislav

    2002-09-06

    Fundamental model compounds for the Hammett equation, meta- and para-substituted benzoic acids, were investigated by the density functional theory at the B3LYP/6-311+G(d,p) level. Energies of 25 acids and of their anions were calculated in all possible conformations and from them the energies of the assumed mixture of conformers. Relative acidities correlated with the experimental gas-phase acidities almost within the experimental uncertainty, much more precisely than in the case of previous calculations at lower levels. Dissection of the substituent effects into those operating in the acid molecule and in the anion was carried out by means of isodesmic reactions starting from monosubstituted benzenes. Both effects are cooperating in the resulting effect on the acidity; those in the acid molecule are smaller but not negligible. They are also responsible for some deviations from the Hammett equation (through-resonance of para donor substituents) and for the weaker resonance in the acid molecule in meta derivatives; in the anions the inductive and resonance effects are almost equal. On the other hand, the cooperation of effects in the acid and in the anion makes the relative acidity more sensitive to electron withdrawing and is probably one of the reasons why the Hammett equation is so generally valid.

  7. Comparison of Butyric acid concentrations in ordinary and probiotic yogurt samples in Iran.

    PubMed

    Vaseji, N; Mojgani, N; Amirinia, C; Iranmanesh, M

    2012-06-01

    Butyric acid has many applications in chemical, food and pharmaceutical industries. Applications of butyric acid are as an additive to food, flavorings, varnishes, perfumes, pharmaceuticals and disinfectants. Butyric acid concentrations have positive impact on the quality control of milk, yogurt and other probiotic dairy products. The present investigation was undertaken to determine and compare the concentrations of butyric acid (C4) in the ordinary and probiotic yogurt samples by GC method. Probiotic yogurt samples were prepared under laboratory scale conditions using two different commercial starters ABY1 and 211, while ordinary yogurt samples lacked the probiotic starter cultures. All samples were analyzed in duplicate, for C4 concentrations by gas chromatography after day 1, 2, 10 and 20 of production, during storage at 4°C. The results were analyzed using ANOVA and Duncan test. The level of the mentioned fatty acid in ABY1 yogurt sample was significantly higher (0.2%) than in 211 samples (0.17%). These values were significantly lower in ordinary yogurt samples and only 0.07% was recorded in these samples on first day of storage which decreased gradually during storage. The level of reduction in the yogurt samples tested during different time intervals was not similar in all the examined samples, and some showed enhanced reduction than other samples. Compared to ordinary yogurt samples, probiotic yogurt samples used in study showed higher levels of butyric acid with increased shelf life.

  8. Comparison of Butyric acid concentrations in ordinary and probiotic yogurt samples in Iran

    PubMed Central

    Vaseji, N; Mojgani, N; Amirinia, C; Iranmanesh, M

    2012-01-01

    Background and objectives Butyric acid has many applications in chemical, food and pharmaceutical industries. Applications of butyric acid are as an additive to food, flavorings, varnishes, perfumes, pharmaceuticals and disinfectants. Butyric acid concentrations have positive impact on the quality control of milk, yogurt and other probiotic dairy products. The present investigation was undertaken to determine and compare the concentrations of butyric acid (C4) in the ordinary and probiotic yogurt samples by GC method. Materials and Methods Probiotic yogurt samples were prepared under laboratory scale conditions using two different commercial starters ABY1 and 211, while ordinary yogurt samples lacked the probiotic starter cultures. All samples were analyzed in duplicate, for C4 concentrations by gas chromatography after day 1, 2, 10 and 20 of production, during storage at 4°C. The results were analyzed using ANOVA and Duncan test. Results The level of the mentioned fatty acid in ABY1 yogurt sample was significantly higher (0.2%) than in 211 samples (0.17%). These values were significantly lower in ordinary yogurt samples and only 0.07% was recorded in these samples on first day of storage which decreased gradually during storage. The level of reduction in the yogurt samples tested during different time intervals was not similar in all the examined samples, and some showed enhanced reduction than other samples. Conclusions Compared to ordinary yogurt samples, probiotic yogurt samples used in study showed higher levels of butyric acid with increased shelf life. PMID:22973475

  9. Urea, Uric Acid, Prolactin and fT4 Concentrations in Aqueous Humor of Keratoconus Patients.

    PubMed

    Stachon, Tanja; Stachon, Axel; Hartmann, Ulrike; Seitz, Berthold; Langenbucher, Achim; Szentmáry, Nóra

    2017-06-01

    Keratoconus is a noninflammatory disease of the cornea associated with progressive thinning and conical shape. Metabolic alterations in the urea cycle, with changes in collagen fibril stability, oxidative stress, thyroid hormones and prolactin with regulatory effect on biosynthesis and biomechanical stability of corneal stroma, may all play a role in keratoconus etiology. Our purpose was to determine urea, uric acid, prolactin and free thyroxin (fT4) concentrations in human aqueous humor (hAH) of keratoconus and cataract patients. hAH was collected from 100 keratoconus (penetrating keratoplasty) (41.9 ± 14.9 years, 69 males) and 100 cataract patients (cataract surgery) (71.2 ± 12.4 years, 58 males). Urea, uric acid, prolactin and fT4 concentrations were measured by Siemens clinical chemistry or immunoassay system. For statistical analysis, a generalized linear model (GLM) was used. Urea concentration was 11.88 ± 3.03 mg/dl in keratoconus and 16.44 ± 6.40 mg/dl in cataract patients, uric acid 2.04 ± 0.59 mg/dl in keratoconus and 2.18 ± 0.73 mg/dl in cataract groups. Prolactin concentration was 3.18 ± 0.34 ng/ml in keratoconus and 3.33 ± 0.32 ng/ml in cataract patients, fT4 20.57 ± 4.76 pmol/l in KC and 19.06 ± 3.86 pmol/l in cataract group. Urea concentration was effected through gender (p = 0.039), age (p = 0.001) and diagnosis (p = 0.025). Uric acid concentration was not effected through any of the analyzed parameters (p > 0.056). Prolactin and fT4 concentration were effected only through diagnosis (p = 0.009 and p = 0.006). Urea and prolactin concentrations are decreased, fT4 concentration is increased in aqueous humor of keratoconus patients, and uric acid concentration remains unchanged. Urea concentration in aqueous humor is also increased in older and male patients. Therefore, metabolic disorder and hormonal balance may both have an impact on keratoconus development. Further studies are necessary to assess the specific impact.

  10. Capillary electrophoresis of inorganic anions.

    PubMed

    Kaniansky, D; Masár, M; Marák, J; Bodor, R

    1999-02-26

    This review deals with the separation mechanisms applied to the separation of inorganic anions by capillary electrophoresis (CE) techniques. It covers various CE techniques that are suitable for the separation and/or determination of inorganic anions in various matrices, including capillary zone electrophoresis, micellar electrokinetic chromatography, electrochromatography and capillary isotachophoresis. Detection and sample preparation techniques used in CE separations are also reviewed. An extensive part of this review deals with applications of CE techniques in various fields (environmental, food and plant materials, biological and biomedical, technical materials and industrial processes). Attention is paid to speciations of anions of arsenic, selenium, chromium, phosphorus, sulfur and halogen elements by CE.

  11. Mobilization of aluminum by the acid percolates within unsaturated zone of sandstones.

    PubMed

    Navrátil, Tomáš; Vařilová, Zuzana; Rohovec, Jan

    2013-09-01

    The area of the Black Triangle has been exposed to extreme levels of acid deposition in the twentieth century. The chemical weathering of sandstones found within the Black Triangle became well-known phenomenon. Infiltration of acid rain solutions into the sandstone represents the main input of salt components into the sandstone. The infiltrated solutions--sandstone percolates--react with sandstone matrix and previously deposited materials such as salt efflorescence. Acidic sandstone percolates pH 3.2-4.8 found at ten sites within the National Park Bohemian Switzerland contained high Al-tot (0.8-10 mg L(-1)) concentrations and high concentrations of anions SO4 (5-66 mg L(-1)) and NO3 (2-42 mg L(-1)). A high proportion (50-98 %) of Al-tot concentration in acid percolates was represented by toxic reactive Al(n+). Chemical equilibrium modeling indicated as the most abundant Al species Al(3+), AlSO4 (+), and AlF(2+). The remaining 2-50 % of Al-tot concentration was present in the form of complexes with dissolved organic matter Al-org. Mobilization and transport of Al from the upper zones of sandstone causes chemical weathering and sandstone structure deterioration. The most acidic percolates contained the highest concentrations of dissolved organic material (estimated up to 42 mg L(-1)) suggesting the contribution of vegetation on sandstone weathering processes. Very low concentrations of Al-tot in springs at BSNP suggest that Al mobilized in unsaturated zone is transported deeper into the sandstone. This process of mobilization could represent a threat for the water quality small-perched aquifers.

  12. Kinetics of nonoxidative leaching of galena in perchloric, hydrobromic, and hydrochloric acid solutions

    NASA Astrophysics Data System (ADS)

    Núñez, C.; Espiell, F.; García-Zayas, J.

    1988-08-01

    Several kinetic studies are presented on the nonoxidative leaching of galena with solutions of hydrocloric, hydrobromic, and perchloric acid. The kinetic parameters were set up in terms of the mean ionic activities of the electrolytes. The apparent order of reaction for the mean ionic activity of perchloric acid is one. For hydrochloric acid the order of reaction over a wide range of concentrations is 3/2 with respect to its mean activity. For hydrobromic acid, whose anion has greater complex-forming power for lead than HC1, the order of reaction is 2. Activation energies are 64.4 kJ/mole for HC1, 71.5 kJ/mole for HC104, and 66.5 kJ mole for HBr. The complete kinetic equations are given for the three reactions.

  13. Semithiobambus[6]uril is a transmembrane anion transporter.

    PubMed

    Lang, Chao; Mohite, Amar; Deng, Xiaoli; Yang, Feihu; Dong, Zeyuan; Xu, Jiayun; Liu, Junqiu; Keinan, Ehud; Reany, Ofer

    2017-07-04

    Semithiobambus[6]uril is shown to be an efficient transmembrane anion transporter. Although all bambusuril analogs (having either O, S or N atoms in their portals) are excellent anion binders, only the sulfur analog is also an effective anion transporter capable of polarizing lipid membranes through selective anion uniport. This notable divergence reflects significant differences in the lipophilic character of the bambusuril analogs.

  14. Detection of naphthenic acids in fish exposed to commercial naphthenic acids and oil sands process-affected water.

    PubMed

    Young, R F; Orr, E A; Goss, G G; Fedorak, P M

    2007-06-01

    Naphthenic acids are a complex mixture of carboxylic acids that occur naturally in petroleum. During the extraction of bitumen from the oil sands in northeastern Alberta, Canada, naphthenic acids are released into the aqueous phase and these acids become the most toxic components in the process-affected water. Although previous studies have exposed fish to naphthenic acids or oil sands process-affected waters, there has been no analytical method to specifically detect naphthenic acids in fish. Here, we describe a qualitative method to specifically detect these acids. In 96-h static renewal tests, rainbow trout (Oncorhynchus mykiss) fingerlings were exposed to three different treatments: (1) fed pellets that contained commercial naphthenic acids (1.5mg g(-1) of food), (2) kept in tap water that contained commercial naphthenic acids (3mg l(-1)) and (3) kept in an oil sands process-affected water that contained 15mg naphthenic acids l(-1). Five-gram samples of fish were homogenized and extracted, then the mixture of free fatty acids and naphthenic acids was isolated from the extract using strong anion exchange chromatography. The mixture was derivatized and analyzed by gas chromatography-mass spectrometry. Reconstructed ion chromatograms (m/z=267) selectively detected naphthenic acids. These acids were present in each fish that was exposed to naphthenic acids, but absent in fish that were not exposed to naphthenic acids. The minimum detectable concentration was about 1microg naphthenic acids g(-1) of fish.

  15. Effects of debrisoquin and haloperidol on plasma homovanillic acid concentration in schizophrenic patients.

    PubMed

    Davidson, M; Losonczy, M F; Mohs, R C; Lesser, J C; Powchik, P; Freed, L B; Davis, B M; Mykytyn, V V; Davis, K L

    1987-12-01

    Plasma levels of the dopamine metabolite homovanillic acid (pHVA) may potentially reflect upon central dopamine activity. This study examines the effects of debrisoquin, haloperidol, and the two drugs combined on pHVA concentrations of schizophrenic patients. Debrisoquin is a drug that suppresses the peripheral formation of homovanillic acid without affecting the central formation. Acute haloperidol administration consistently increased pHVA concentrations in patients pretreated or not pretreated with debrisoquin, suggesting that this increment reflects haloperidol's central and not peripheral effects.

  16. Anion channels: master switches of stress responses.

    PubMed

    Roelfsema, M Rob G; Hedrich, Rainer; Geiger, Dietmar

    2012-04-01

    During stress, plant cells activate anion channels and trigger the release of anions across the plasma membrane. Recently, two new gene families have been identified that encode major groups of anion channels. The SLAC/SLAH channels are characterized by slow voltage-dependent activation (S-type), whereas ALMT genes encode rapid-activating channels (R-type). Both S- and R-type channels are stimulated in guard cells by the stress hormone ABA, which leads to stomatal closure. Besides their role in ABA-dependent stomatal movement, anion channels are also activated by biotic stress factors such as microbe-associated molecular patterns (MAMPs). Given that anion channels occur throughout the plant kingdom, they are likely to serve a general function as master switches of stress responses. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Endogenous flow of amino acids in the avian ileum as influenced by increasing dietary peptide concentrations.

    PubMed

    Ravindran, Velmurugu; Morel, Patrick C H; Rutherfurd, Shane M; Thomas, Donald V

    2009-03-01

    The aim of the present study was to establish whether feeding broiler chickens with diets containing increasing dietary peptide concentrations would cause increases in ileal endogenous amino acid flow. The flow of N and most amino acids increased quadratically (P < 0.05 to 0.001) with increasing dietary concentrations of peptides. The exceptions were the flow of threonine, serine, glycine, tyrosine and cystine, which increased linearly (P < 0.001) with dietary peptide levels. Another notable exception to the general trend was the flow of proline, which was significantly higher (P < 0.01) in birds fed the protein-free diet. The amino acid profile of endogenous protein, expressed as proportion of crude protein, indicated that the ratios of threonine, glutamic acid, proline, glycine, leucine, histidine, arginine and cystine were influenced (P < 0.05) with increasing dietary peptide concentrations. In general, compared with the protein-free diet, the ratios of threonine and arginine in endogenous protein were lower (P < 0.05) and those of glutamic acid, glycine and histidine were greater (P < 0.05) in diets with high concentrations of peptides. The ratio of proline was found to decrease (P < 0.05) with increasing dietary peptide concentrations. These changes in the amino acid profile of endogenous protein are probably reflective of changes in the output of one or more of the components of endogenous protein. Overall, the present results demonstrated that increasing dietary peptide concentrations increased the flow of endogenous amino acid flow at the terminal ileum of broiler chickens in a dose-dependent manner and also caused changes in the composition of endogenous protein. The observed changes in endogenous amino flow will influence the maintenance requirements for amino acids and also have implications for the calculation of true digestibility coefficient of feedstuffs.

  18. Anion recognition using newly synthesized hydrogen bonding disubstituted phenylhydrazone-based receptors: poly(vinyl chloride)-based sensor for acetate.

    PubMed

    Gupta, Vinod K; Goyal, Rajendra N; Sharma, Ram A

    2008-08-15

    A potentiometric acetate-selective sensor, based on the use of butane-2,3-dione,bis[(2,4-dinitrophenyl)hydrazone] (BDH) as a neutral carrier in poly(vinyl chloride) (PVC) matrix, is reported. Effect of various plasticizers and cation excluder, cetryaltrimethylammonium bromide (CTAB) was studied. The best performance was obtained with a membrane composition of PVC:BDH:CTAB ratio (w/w; mg) of 160:8:8. The sensor exhibits significantly enhanced selectivity toward acetate ions over a wide concentration range 5.0 x 10(-6) to 1.0 x 10(-1)M with a lower detection limit of 1.2 x 10(-6)M within pH range 6.5-7.5 with a response time of <15s and a Nernstian slope of 60.3+/-0.3 mV decade(-1) of activity. Influences of the membrane composition, and possible interfering anions were investigated on the response properties of the electrode. Fast and stable response, good reproducibility and long-term stability are demonstrated. The sensor has a response time of 15s and can be used for at least 65 days without any considerable divergence in their potential response. Selectivity coefficients determined with the separate solution method (SSM) and fixed interference method (FIM) indicate that high selectivity for acetate ion. The proposed electrode shows fairly good discrimination of acetate from several inorganic and organic anions. It was successfully applied to direct determination of acetate within food preservatives. Total concentration of acetic acid in vinegar samples were determined by direct potentiometry and the values agreed with those mentioned by the manufacturers.

  19. NUCLEIC ACID CONCENTRATION AND RADIOSENSITIVITY OF THE SCORPION ANDROCTONUS AMOREUXI AUD. AND SAV (in French)

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

    Pascaud, X.; Niaussat, P.

    1963-01-01

    The concentration of desoxyribonucleic acid and of ribonucleic acid in the soft tissues was determined for the two invertebrates of the arid zone, the scorpion Androctonus amoreuxi Aud. and Sav. and the tenebrionide Pimelia angulata expiata Peyer. The radiosensitivity to gamma rays had been previously determined: LD/sub 50/30// days is 100,000 r for Androctonus and 40,000 for Pimelia. The mean rate of nucleic acids determined in the scorpion was relatively low. A possible relation between the high radioresistance of the scorpion and the low nucleic acid concentration was discussed. (J.S.R.)

  20. Effect of citric acid concentration and hydrolysis time on physicochemical properties of sweet potato starches.

    PubMed

    Surendra Babu, Ayenampudi; Parimalavalli, Ramanathan; Rudra, Shalini Gaur

    2015-09-01

    Physicochemical properties of citric acid treated sweet potato starches were investigated in the present study. Sweet potato starch was hydrolyzed using citric acid with different concentrations (1 and 5%) and time periods (1 and 11 h) at 45 °C and was denoted as citric acid treated starch (CTS1 to CTS4) based on their experimental conditions. The recovery yield of acid treated starches was above 85%. The CTS4 sample displayed the highest amylose (around 31%) and water holding capacity its melting temperature was 47.66 °C. The digestibility rate was slightly increased for 78.58% for the CTS3 and CTS4. The gel strength of acid modified starches ranged from 0.27 kg to 1.11 kg. RVA results of acid thinned starches confirmed a low viscosity profile. CTS3 starch illustrated lower enthalpy compared to all other modified starches. All starch samples exhibited a shear-thinning behavior. SEM analysis revealed that the extent of visible degradation was increased at higher hydrolysis time and acid concentration. The CTS3 satisfied the criteria required for starch to act as a fat mimetic. Overall results conveyed that the citric acid treatment of sweet potato starch with 5% acid concentration and 11h period was an ideal condition for the preparation of a fat replacer. Copyright © 2015 Elsevier B.V. All rights reserved.