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Sample records for affinity solid phase

  1. Peptide-based affinity media for solid-phase extraction of Ochratoxin A from wine samples: Effect of the solid support on binding properties.

    PubMed

    Giovannoli, Cristina; Passini, Cinzia; Volpi, Giorgio; Di Nardo, Fabio; Anfossi, Laura; Baggiani, Claudio

    2015-11-01

    A suitable sample clean up is a key point in the development of an analytical method. Peptide-based affinity media have recently gained attention in the selective extraction of defined target analytes from complex samples. In this paper we investigated the thermodynamic and kinetic binding properties of different stationary phases (Amberlite IRC-50, Lewatit CNP105, Toyopearl CM-650 M, porous silica gel beads and micrometric glass beads) functionalized with a hexapeptide sequence binding the Ochratoxin A. The highest values of the equilibrium binding constant (Keq) and binding site concentration (Bmax) were obtained for Lewatit CNP105 (Keq: 98.1×10(6) M(-1), Bmax: 30.8 μmol/g), followed by Toyopearl and micrometric glass beads, whereas the worst performances were obtained with Amberlite IRC-50 and porous silica gel beads. Also kinetic performances show the same trend. These results highlight that the surface chemical nature has a key role in the binding properties of solid supports used as affinity media for the selective extraction of well-defined target molecules. Finally, Lewatit CNP105 was compared with Amberlite IRC-50 as solid support in SPE extraction of OTA from 14 wine samples fortified with OTA at 2 and 4 μg l(-1) levels. The extracts were analyzed by HPLC with fluorescence detection (λexc 333 nm, λem 460 nm) showing no significant matrix effects, with a LOD and LOQ of 0.45 and 1.5 μgl(-1), respectively, and good recoveries between 71% and 108% for Amberlite IRC-50 and 91% and 101% for Lewatit CNP105. While both supports showed a statistically comparable extraction accuracy, a statistically significant difference was found in terms of extraction precision, confirming that the solid phase based on Lewatit CNP105 performs better than the solid phase based on Amberlite IRC-50. PMID:26452853

  2. Differences in binding affinities of MDA, MDMA, MDEA, Amphetamine, Methamphetamine, and their deuterated analogues to solid-phase extraction cartridges.

    PubMed

    Romberg, R W; Ntamack, A G; Blacik, L J; Kazarian, C M; Snyder, J Jacob; Welsh, E R

    2011-01-01

    This study evaluated the potential for partial separation of drugs from their deuterated internal standards using Cerex(®) Polycrom™ CLIN II solid-phase extraction (SPE) cartridges. After elution from the column and derivatization, gas chromatography-mass spectrometry results showed that the target compound eluted from the SPE cartridge prior to its deuterated form. This elution separation effect was greater for 3,4-methylenedioxymethamphetamine (MDMA) and methamphetamine (MAMP) than for the other drugs studied. When the drugs were eluted in 0.5 mL increments from a 50 mg sorbent bed, no drug appeared in the first fraction. The drug to internal standard ratios (expected value 1.00) for subsequent fractions collected were 1.30, 1.07, and 0.83 for MDA/MDA-d(5); 1.65, 1.18, 0.67, and 0.56 for MDMA/MDMAd(5); and 1.37, 1.18, and 0.95 for MDEA/MDEA-d(6). For d-AMP and d-MAMP, the expected ratio was 0.40. The subsequent ratios were 0.63, 0.46, 0.35, and 0.34 for d-AMP/d-AMP-d(11); and 1.00, 0.59, 0.25, and 0.18 for d-MAMP/d-MAMP-d(14). The affinity of d-MAMPd(14) was shown to be greater than that of d-MAMP-d(5), and deuteration at the propyl end of the molecule was shown to increase binding more than deuteration on the phenyl group.

  3. A solid-phase combinatorial approach for indoloquinolizidine-peptides with high affinity at D(1) and D(2) dopamine receptors.

    PubMed

    Molero, Anabel; Vendrell, Marc; Bonaventura, Jordi; Zachmann, Julian; López, Laura; Pardo, Leonardo; Lluis, Carme; Cortés, Antoni; Albericio, Fernando; Casadó, Vicent; Royo, Miriam

    2015-06-01

    Ligands acting at multiple dopamine receptors hold potential as therapeutic agents for a number of neurodegenerative disorders. Specifically, compounds able to bind at D1R and D2R with high affinity could restore the effects of dopamine depletion and enhance motor activation on degenerated nigrostriatal dopaminergic systems. We have directed our research towards the synthesis and characterisation of heterocycle-peptide hybrids based on the indolo[2,3-a]quinolizidine core. This privileged structure is a water-soluble and synthetically accessible scaffold with affinity for diverse GPCRs. Herein we have prepared a solid-phase combinatorial library of 80 indoloquinolizidine-peptides to identify compounds with enhanced binding affinity at D2R, a receptor that is crucial to re-establish activity on dopamine-depleted degenerated GABAergic neurons. We applied computational tools and high-throughput screening assays to identify 9a{1,3,3} as a ligand for dopamine receptors with nanomolar affinity and agonist activity at D2R. Our results validate the application of indoloquinolizidine-peptide combinatorial libraries to fine-tune the pharmacological profiles of multiple ligands at D1 and D2 dopamine receptors.

  4. Online micro-solid-phase extraction based on boronate affinity monolithic column coupled with high-performance liquid chromatography for the determination of monoamine neurotransmitters in human urine.

    PubMed

    Yang, Xiaoting; Hu, Yufei; Li, Gongke

    2014-05-16

    Quantification of monoamine neurotransmitters is very important in diagnosing and monitoring of patients with neurological disorders. We developed an online analytical method to selectively determine urinary monoamine neurotransmitters, which coupled the boronate affinity monolithic column micro-solid-phase extraction with high-performance liquid chromatography (HPLC). The boronate affinity monolithic column was prepared by in situ polymerization of vinylphenylboronic acid (VPBA) and N,N'-methylenebisacrylamide (MBAA) in a stainless capillary column. The prepared monolithic column showed good permeability, high extraction selectivity and capacity. The column-to-column reproducibility was satisfactory and the enrichment factors were 17-243 for four monoamine neurotransmitters. Parameters that influence the online extraction efficiency, including pH of sample solution, flow rate of extraction and desorption, extraction volume and desorption volume were investigated. Under the optimized conditions, the developed method exhibited low limit of detection (0.06-0.80μg/L), good linearity (with R(2) between 0.9979 and 0.9993). The recoveries in urine samples were 81.0-105.5% for four monoamine neurotransmitters with intra- and inter-day RSDs of 2.1-8.2% and 3.7-10.6%, respectively. The online analytical method was sensitive, accurate, selective, reliable and applicable to analysis of trace monoamine neurotransmitters in human urine sample.

  5. Affinity-purified antibodies of defined specificity for use in a solid-phase microplate radioimmunoassay of human Tamm-Horsfall glycoprotein in urine.

    PubMed

    Hunt, J S; McGiven, A R; Groufsky, A; Lynn, K L; Taylor, M C

    1985-05-01

    Rabbit antibodies to human Tamm-Horsfall glycoprotein (prepared by salt precipitation from normal urine) were purified by affinity chromatography using columns containing Tamm-Horsfall glycoprotein linked to CNBr-activated Sepharose 4B. The specificity of these antibodies was determined by analysis of their binding characteristics on Western blots of Tamm-Horsfall protein from sodium dodecyl sulphate/polyacrylamide gradient gels and comparison with the reactivity of monoclonal antibodies to this glycoprotein. Optimal conditions of adsorption to poly(vinyl chloride) microtitre plates were established such that these purified antibodies could be used in a solid-phase radioimmunoassay for the determination of urinary Tamm-Horsfall-glycoprotein concentration. The specificity of the immunoassay was confirmed by competitive inhibition of the urinary Tamm-Horsfall glycoprotein by purified freeze-dried material in solution. A standard curve obtained with this material showed the radioimmunoassay to have a sensitivity of at least 5 ng/ml, with linearity between 30 and 600 ng/ml. The mean coefficient of variation over the linear section of the curve was 11.3 +/- 2.2% (n = 13). The effects of dialysis and freezing of urine samples before determination of Tamm-Horsfall-glycoprotein concentrations were investigated and the mean 24 h urinary excretion rate in 60 normal donors was shown to be 84.9 +/- 44.1 mg.

  6. Comprehensive profiling of ribonucleosides modification by affinity zirconium oxide-silica composite monolithic column online solid-phase microextraction - Mass spectrometry analysis.

    PubMed

    Jiang, Han-Peng; Chu, Jie-Mei; Lan, Meng-Dan; Liu, Ping; Yang, Na; Zheng, Fang; Yuan, Bi-Feng; Feng, Yu-Qi

    2016-09-01

    More than 140 modified ribonucleosides have been identified in RNA. Determination of endogenous modified ribonucleosides in biological fluids may serve as non-invasive disease diagnostic strategy. However, detection of the modified ribonucleosides in biological fluids is challenging, especially for the low abundant modified ribonucleosides due to the serious matrix interferences of biological fluids. Here, we developed a facile preparation strategy and successfully synthesized zirconium oxide-silica (ZrO2/SiO2) composite capillary monolithic column that exhibited excellent performance for the selective enrichment of cis-diol-containing compounds. Compared with the boronate-based affinity monolith, the ZrO2/SiO2 monolith showed ∼2 orders of magnitude higher extraction capacity and can be used under physiological pH (pH 6.5-7.5). Using the prepared ZrO2/SiO2 composite monolith as the trapping column and reversed-phase C18 column as the analytical column, we further established an online solid-phase microextraction (SPME) in combination with liquid chromatography-mass spectrometry (online SPME-LC-MS/MS) analysis for the comprehensive profiling of ribonucleosides modification in human urine. Our results showed that 68 cis-diol-containing ribosylated compounds were identified in human urine, which is, to the best of our knowledge, the highest numbers of cis-diol-containing compounds were determined in a single analysis. It is worth noting that four modified ribonucleosides were discovered in the human urine for the first time. In addition, the quantification results from the pooled urine samples showed that compared to healthy controls, the contents of sixteen ribose conjugates in the urine of gastric cancer, eleven in esophagus cancer and seven in lymphoma increased more than two folds. Among these ribose conjugates, four ribose conjugates increased more than two folds in both gastric cancer and esophagus cancer; three ribose conjugates increased more than two

  7. Comprehensive profiling of ribonucleosides modification by affinity zirconium oxide-silica composite monolithic column online solid-phase microextraction - Mass spectrometry analysis.

    PubMed

    Jiang, Han-Peng; Chu, Jie-Mei; Lan, Meng-Dan; Liu, Ping; Yang, Na; Zheng, Fang; Yuan, Bi-Feng; Feng, Yu-Qi

    2016-09-01

    More than 140 modified ribonucleosides have been identified in RNA. Determination of endogenous modified ribonucleosides in biological fluids may serve as non-invasive disease diagnostic strategy. However, detection of the modified ribonucleosides in biological fluids is challenging, especially for the low abundant modified ribonucleosides due to the serious matrix interferences of biological fluids. Here, we developed a facile preparation strategy and successfully synthesized zirconium oxide-silica (ZrO2/SiO2) composite capillary monolithic column that exhibited excellent performance for the selective enrichment of cis-diol-containing compounds. Compared with the boronate-based affinity monolith, the ZrO2/SiO2 monolith showed ∼2 orders of magnitude higher extraction capacity and can be used under physiological pH (pH 6.5-7.5). Using the prepared ZrO2/SiO2 composite monolith as the trapping column and reversed-phase C18 column as the analytical column, we further established an online solid-phase microextraction (SPME) in combination with liquid chromatography-mass spectrometry (online SPME-LC-MS/MS) analysis for the comprehensive profiling of ribonucleosides modification in human urine. Our results showed that 68 cis-diol-containing ribosylated compounds were identified in human urine, which is, to the best of our knowledge, the highest numbers of cis-diol-containing compounds were determined in a single analysis. It is worth noting that four modified ribonucleosides were discovered in the human urine for the first time. In addition, the quantification results from the pooled urine samples showed that compared to healthy controls, the contents of sixteen ribose conjugates in the urine of gastric cancer, eleven in esophagus cancer and seven in lymphoma increased more than two folds. Among these ribose conjugates, four ribose conjugates increased more than two folds in both gastric cancer and esophagus cancer; three ribose conjugates increased more than two

  8. Study of immobilized metal affinity chromatography sorbents for the analysis of peptides by on-line solid-phase extraction capillary electrophoresis-mass spectrometry.

    PubMed

    Ortiz-Martin, Lorena; Benavente, Fernando; Medina-Casanellas, Silvia; Giménez, Estela; Sanz-Nebot, Victoria

    2015-03-01

    Several commercial immobilized metal affinity chromatography sorbents were evaluated in this study for the analysis of two small peptide fragments of the amyloid β-protein (Aβ) (Aβ(1-15) and Aβ(10-20) peptides) by on-line immobilized metal affinity SPE-CE (IMA-SPE-CE). The performance of a nickel metal ion (Ni(II)) sorbent based on nitrilotriacetic acid as a chelating agent was significantly better than two copper metal ion (Cu(II)) sorbents based on iminodiacetic acid. A BGE of 25 mM phosphate (pH 7.4) and an eluent of 50 mM imidazole (in BGE) yielded a 25-fold and 5-fold decrease in the LODs by IMA-SPE-CE-UV for Aβ(1-15) and Aβ(10-20) peptides (0.1 and 0.5 μg/mL, respectively) with regard to CE-UV (2.5 μg/mL for both peptides). The phosphate BGE was also used in IMA-SPE-CE-MS, but the eluent needed to be substituted by a 0.5% HAc v/v solution. Under optimum preconcentration and detection conditions, reproducibility of peak areas and migration times was acceptable (23.2 and 12.0%RSD, respectively). The method was more sensitive for Aβ(10-20) peptide, which could be detected until 0.25 μg/mL. Linearity for Aβ(10-20) peptide was good in a narrow concentration range (0.25-2.5 μg/mL, R(2) = 0.93). Lastly, the potential of the optimized Ni(II)-IMA-SPE-CE-MS method for the analysis of amyloid peptides in biological fluids was evaluated by analyzing spiked plasma and serum samples. PMID:25640944

  9. Solid phase extraction membrane

    DOEpatents

    Carlson, Kurt C [Nashville, TN; Langer, Roger L [Hudson, WI

    2002-11-05

    A wet-laid, porous solid phase extraction sheet material that contains both active particles and binder and that possesses excellent wet strength is described. The binder is present in a relatively small amount while the particles are present in a relatively large amount. The sheet material is sufficiently strong and flexible so as to be pleatable so that, for example, it can be used in a cartridge device.

  10. Non-affine fields in solid-solid transformations: the structure and stability of a product droplet.

    PubMed

    Paul, Arya; Sengupta, Surajit; Rao, Madan

    2014-01-01

    We describe the microstructure, morphology, and dynamics of growth of a droplet of martensite nucleating in a parent austenite during a solid-solid transformation, using a Landau theory written in terms of both conventional affine elastic deformations and non-affine deformations. Non-affineness, φ, serves as a source of strain incompatibility and screens long-ranged elastic interactions. It is produced wherever the local stress exceeds a threshold and anneals diffusively thereafter. Using a variational calculation, we find three types of stable solution (labeled I, II, and III) for the structure of the product droplet, depending on the stress threshold and the scaled mobilities of φ parallel and perpendicular to the parent-product interface. The profile of the non-affine field φ is different in these three solutions: I is characterized by a vanishingly small φ, II admits large values of φ localized in regions of high stress within the parent-product interface, and III is a structure in which φ completely wets the parent-product interface. The width l and size W of the twins follow the relation l is proportional to √W in solution I; this relation does not hold for II or III. We obtain a dynamical phase diagram featuring these solutions, and argue that they represent specific solid-state microstructures.

  11. Gas-phase lithium cation affinity of glycine.

    PubMed

    Bourcier, Sophie; Chiaa, Ru Xuan; Mimbong, Rosa Ngo Biboum; Bouchoux, Guy

    2015-01-01

    The gas-phase lithium cation binding thermochemistry of glycine has been determined theoretically by quantum chemical calculations at the G4 level and experimentally by the extended kinetic method using electrospray ionization quadrupole time-of-flight tandem mass spectrometry. The lithium cation affinity of glycine, ∆(Li)H°(298)(GLY), i.e. the∆(Li)H°(298) of the reaction GlyLi(+)→ Gly + Li(+)) given by the G4 method is equal to 241.4 kJ.mol(-1) if only the most stable conformer of glycine is considered or to 242.3 kJ.mol(-1) if the 298K equilibrium mixture of neutral conformers is included in the calculation. The ∆(Li)H°(298)(GLY) deduced from the extended kinetic method is obviously dependent on the choice of the Li(+) affinity scale, thus∆(Li)H°(298)(GLY) is equal to 228.7±0.9(2.0) kJ.mol(- 1) if anchored to the recently re-evaluated lithium cation affinity scale but shifted to 235.4±1.0 kJ.mol(-1) if G4 computed lithium cation affinities of the reference molecules is used. This difference of 6.3 kJ.mol(-1) may originate from a compression of the experimental lithium affinity scale in the high ∆(Li)H°(298) region. The entropy change associated with the reaction GlyLi(+)→Gly + Li(+) reveals a gain of approximately 15 J.mol(-) 1.K(-1) with respect to monodentate Li(+) acceptors. The origin of this excess entropy is attributed to the bidentate interaction between the Li(+) cation and both the carbonyl oxygen and the nitrogen atoms of glycine. The computed G4 Gibbs free energy,∆(Li)G°(298)(GLY) is equal to 205.3 kJ.mol(-1), a similar result, 201.0±3.4 kJ.mol(-1), is obtained from the experiment if the∆(Li)G°(298) of the reference molecules is anchored on the G4 results. PMID:26307695

  12. Gas-phase lithium cation affinity of glycine.

    PubMed

    Bourcier, Sophie; Chiaa, Ru Xuan; Mimbong, Rosa Ngo Biboum; Bouchoux, Guy

    2015-01-01

    The gas-phase lithium cation binding thermochemistry of glycine has been determined theoretically by quantum chemical calculations at the G4 level and experimentally by the extended kinetic method using electrospray ionization quadrupole time-of-flight tandem mass spectrometry. The lithium cation affinity of glycine, ∆(Li)H°(298)(GLY), i.e. the∆(Li)H°(298) of the reaction GlyLi(+)→ Gly + Li(+)) given by the G4 method is equal to 241.4 kJ.mol(-1) if only the most stable conformer of glycine is considered or to 242.3 kJ.mol(-1) if the 298K equilibrium mixture of neutral conformers is included in the calculation. The ∆(Li)H°(298)(GLY) deduced from the extended kinetic method is obviously dependent on the choice of the Li(+) affinity scale, thus∆(Li)H°(298)(GLY) is equal to 228.7±0.9(2.0) kJ.mol(- 1) if anchored to the recently re-evaluated lithium cation affinity scale but shifted to 235.4±1.0 kJ.mol(-1) if G4 computed lithium cation affinities of the reference molecules is used. This difference of 6.3 kJ.mol(-1) may originate from a compression of the experimental lithium affinity scale in the high ∆(Li)H°(298) region. The entropy change associated with the reaction GlyLi(+)→Gly + Li(+) reveals a gain of approximately 15 J.mol(-) 1.K(-1) with respect to monodentate Li(+) acceptors. The origin of this excess entropy is attributed to the bidentate interaction between the Li(+) cation and both the carbonyl oxygen and the nitrogen atoms of glycine. The computed G4 Gibbs free energy,∆(Li)G°(298)(GLY) is equal to 205.3 kJ.mol(-1), a similar result, 201.0±3.4 kJ.mol(-1), is obtained from the experiment if the∆(Li)G°(298) of the reference molecules is anchored on the G4 results.

  13. A solid phase antibody screen.

    PubMed

    Plapp, F V; Sinor, L T; Rachel, J M; Beck, M L; Coenen, W M; Bayer, W L

    1984-12-01

    An automated solid phase antibody screen (SPAS) in microplates has been developed. Red blood cell (RBC) adherence was used as the end point instead of agglutination. Consequently, positive and negative reactions were readily distinguished by a microplate spectrophotometer. The SPAS performed as well as conventional antiglobulin methods for detecting IgG antibodies in donor sera and had increased sensitivity as determined by serial dilutions of antibodies.

  14. SODIUM ALUMINOSILICATE SOLIDS AFFINITY FOR CESIUM AND ACTINIDES

    SciTech Connect

    Peters, T; Bill Wilmarth, B; Samuel Fink, S

    2007-07-31

    Washed sodium-aluminosilicate (NAS) solids at initial concentrations of 3.55 and 5.4 g/L sorb or uptake virtually no cesium over 288 hours, nor do any NAS solids generated during that time. These concentrations of solids are believed to conservatively bound current and near-term operations. Hence, the NAS solids should not have affected measurements of the cesium during the mass transfer tests and there is minimal risk of accumulating cesium during routine operations (and hence posing a gamma radiation exposure risk in maintenance). With respect to actinide uptake, it appears that NAS solids sorb minimal quantities of uranium - up to 58 mg U per kg NAS solid. The behavior with plutonium is less well understood. Additional study may be needed for radioactive operations relative to plutonium or other fissile component sorption or trapping by the solids. We recommend this testing be incorporated in the planned tests using samples from Tank 25F and Tank 49H to extend the duration to bound expected inventory time for solution.

  15. Aptamer stationary phase for protein capture in affinity capillary chromatography.

    PubMed

    Connor, Adam C; McGown, Linda B

    2006-04-14

    The thrombin-binding DNA aptamer was used with thrombin as a model system to investigate protein capture using aptamer stationary phases in affinity capillary chromatography. The aptamer was covalently attached to the inner surface of a bare fused-silica glass capillary to serve as the stationary phase. Proteins were loaded onto the capillary via an applied pressure. The capillary was then washed to remove unbound and non-specifically associated proteins. Finally, the bound protein was released and eluted using 20 mM Tris buffer containing 8 M urea, pH 7.3, at 50 degrees C. Eluate was collected after each step (load, wash and elute) and relative amounts of protein each were compared using fluorescence spectroscopy. The identity of the protein in the collections was confirmed using matrix assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry. The experiment was repeated for thrombin on a bare (unmodified) capillary and a capillary coated with a scrambled-sequence, non-G-quartet forming oligonucleotide that does not bind with thrombin. The results show that the aptamer stationary phase captures approximately three times as much thrombin as the control columns. The experiment was also repeated using human serum albumin (HSA) alone and in an equimolar mixture with thrombin. HSA was not retained on the aptamer capillary, nor did it affect the capture of thrombin from the mixture.

  16. Colorimetric Solid-Phase Extractor

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The heart of a colorimetric solid phase extractor (CSPE) test kit quickly measures the concentration of the biocides silver or iodine in astronauts' drinking water to determine whether concentrations are safe. When 10 milliliters (ml) of water is drawn through the disk, the disk will turn color (yellow in this picture for iodine) indicating the presence of the biocides. The device could someday be used to test water safety at reservoirs and water treatment plants on Earth. (photo credit: Microanalytical Instrumentation Center, Iowa State University).

  17. Solid phase microextraction field kit

    DOEpatents

    Nunes, Peter J.; Andresen, Brian D.

    2005-08-16

    A field kit for the collection, isolation and concentration of trace amounts of high explosives (HE), biological weapons (BW) and chemical weapons (CW) residues in air, soil, vegetation, swipe, and liquid samples. The field kit includes a number of Solid Phase Microextraction (SPME) fiber and syringe assemblies in a hermetically sealed transportation container or tubes which includes a sampling port, a number of extra SPME fiber and syringe assemblies, the fiber and syringe assemblies including a protective cap for the fiber, and an extractor for the protective cap, along with other items including spare parts, protective glove, and an instruction manual, all located in an airtight container.

  18. Allantoin as a solid phase adsorbent for removing endotoxins.

    PubMed

    Vagenende, Vincent; Ching, Tim-Jang; Chua, Rui-Jing; Gagnon, Pete

    2013-10-01

    In this study we present a simple and robust method for removing endotoxins from protein solutions by using crystals of the small-molecule compound 2,5-dioxo-4-imidazolidinyl urea (allantoin) as a solid phase adsorbent. Allantoin crystalline powder is added to a protein solution at supersaturated concentrations, endotoxins bind and undissolved allantoin crystals with bound endotoxins are removed by filtration or centrifugation. This method removes an average of 99.98% endotoxin for 20 test proteins. The average protein recovery is ∼80%. Endotoxin binding is largely independent of pH, conductivity, reducing agent and various organic solvents. This is consistent with a hydrogen-bond based binding mechanism. Allantoin does not affect protein activity and stability, and the use of allantoin as a solid phase adsorbent provides better endotoxin removal than anion exchange, polymixin affinity and biological affinity methods for endotoxin clearance.

  19. Solid Phase Characterization of Solids Recovered from Failed Sluicer Arm

    SciTech Connect

    Cooke, Gary A.

    2015-03-09

    The Enclosure to this memo discusses the solid phase characterization of a solid sample that was retrieved from the single-shell Tank 241-C-111 extended reach sluicer #2. This sluicer, removed from riser #3 on September 25, 2014, was found to have approximately 0.4 gallons of solid tank waste adhering to the nozzle area.

  20. A comparison of observables for solid-solid phase transitions

    SciTech Connect

    Smilowitz, Laura B; Henson, Bryan F; Romero, Jerry J

    2009-01-01

    The study of solid-solid phase transformations is hindered by the difficulty of finding a volumetric probe to use as a progress variable. Solids are typically optically opaque and heterogeneous. Over the past several years, second harmonic generation (SHG) has been used as a kinetic probe for a solid-solid phase transition in which the initial and final phases have different symmetries. Bulk generation of SHG is allowed by symmetry only in noncentrosymmetric crystallographic space groups. For the organic energetic nitramine octahydro-1,3 ,5,7 -tetranitro-1,3 ,5,7 -tatrazocine (HMX), the beta phase is centro symmetric (space group P2{sub 1}/c) and the delta phase iS noncentrosymmetric (space group P6{sub 1}22) making SHG an extremely sensitive, essentially zero background probe of the phase change progress. We have used SHG as a tool to follow the progress of the transformation from beta to delta phase during the solid-solid transformation. However, kinetic models of the transformation derived using different observables from several other groups have differed, showing later onset for the phase change and faster progression to completion. In this work, we have intercompared several techniques to understand these differences. The three techniques discussed are second harmonic generation, Raman spectroscopy, and differential scanning calorimetry (DSC). The progress of the beta to delta phase transition in HMX observed with each of these different probes will be discussed and advantages and disadvantages of each technique described. This paper compares several different observables for use in measuring the kinetics of solid-solid phase transitions. Relative advantages and disadvantages for each technique are described and a direct comparison of results is made for the beta to delta polymorphic phase transition of the energetic nitramine, octahydro-1,3,5,7-tetranitro-1,3,5,7-tatrazocine.

  1. Solid-phase synthesis of molecularly imprinted nanoparticles.

    PubMed

    Canfarotta, Francesco; Poma, Alessandro; Guerreiro, Antonio; Piletsky, Sergey

    2016-03-01

    Molecularly imprinted polymers (MIPs) are synthetic materials, generally based on acrylic or methacrylic monomers, that are polymerized in the presence of a specific target molecule called the 'template' and capable of rebinding selectively to this target molecule. They have the potential to be low-cost and robust alternatives to biomolecules such as antibodies and receptors. When prepared by traditional synthetic methods (i.e., with free template in solution), their usefulness has been limited by high binding site heterogeneity, the presence of residual template and the fact that the production methods are complex and difficult to standardize. To overcome some of these limitations, we developed a method for the synthesis of MIP nanoparticles (nanoMIPs) using an innovative solid-phase approach, which relies on the covalent immobilization of the template molecules onto the surface of a solid support (glass beads). The obtained nanoMIPs are virtually free of template and demonstrate high affinity for the target molecule (e.g., melamine and trypsin in our published work). Because of an affinity separation step performed on the solid phase after polymerization, poor binders and unproductive polymer are removed, so the final product has more uniform binding characteristics. The overall protocol, starting from the immobilization of the template onto the solid phase and including the purification and characterization of the nanoparticles, takes up to 1 week.

  2. Solid-phase synthesis of molecularly imprinted nanoparticles.

    PubMed

    Canfarotta, Francesco; Poma, Alessandro; Guerreiro, Antonio; Piletsky, Sergey

    2016-03-01

    Molecularly imprinted polymers (MIPs) are synthetic materials, generally based on acrylic or methacrylic monomers, that are polymerized in the presence of a specific target molecule called the 'template' and capable of rebinding selectively to this target molecule. They have the potential to be low-cost and robust alternatives to biomolecules such as antibodies and receptors. When prepared by traditional synthetic methods (i.e., with free template in solution), their usefulness has been limited by high binding site heterogeneity, the presence of residual template and the fact that the production methods are complex and difficult to standardize. To overcome some of these limitations, we developed a method for the synthesis of MIP nanoparticles (nanoMIPs) using an innovative solid-phase approach, which relies on the covalent immobilization of the template molecules onto the surface of a solid support (glass beads). The obtained nanoMIPs are virtually free of template and demonstrate high affinity for the target molecule (e.g., melamine and trypsin in our published work). Because of an affinity separation step performed on the solid phase after polymerization, poor binders and unproductive polymer are removed, so the final product has more uniform binding characteristics. The overall protocol, starting from the immobilization of the template onto the solid phase and including the purification and characterization of the nanoparticles, takes up to 1 week. PMID:26866789

  3. Stable solid-phase Rh antigen.

    PubMed

    Yared, M A; Moise, K J; Rodkey, L S

    1997-12-01

    Numerous investigators have attempted to isolate the Rh antigens in a stable, immunologically reactive form since the discovery of the Rh system over 56 years ago. We report here a successful and reproducible approach to solubilizing and adsorbing the human Rh antigen(s) to a solid-phase matrix in an antigenically active form. Similar results were obtained with rabbit A/D/F red blood cell antigens. The antigen preparation was made by dissolution of the red blood cell membrane lipid followed by fragmentation of the residual cytoskeleton in an EDTA solution at low ionic strength. The antigenic activity of the soluble preparations was labile in standard buffers but was stable in zwitterionic buffers for extended periods of time. Further studies showed that the antigenic activity of these preparations was enhanced, as was their affinity for plastic surfaces, in the presence of acidic zwitterionic buffers. Adherence to plastic surfaces at low pH maintained antigenic reactivity and specificity for antibody was retained. The data show that this approach yields a stable form of antigenically active human Rh D antigen that could be used in a red blood cell-free assay for quantitative analysis of Rh D antibody and for Rh D antibody immunoadsorption and purification.

  4. Ultrasensitive Analysis of Binding Affinity of HIV Receptor and Neutralizing Antibody Using Solution-Phase Electrochemiluminescence Assay

    PubMed Central

    Xu, Xiao-Hong Nancy; Wen, Zhaoyang; Brownlow, William J.

    2012-01-01

    Binding of a few ligand molecules with its receptors on cell surface can initiate cellular signaling transduction pathways, and trigger viral infection of host cells. HIV-1 infects host T-cells by binding its viral envelope protein (gp120) with its receptor (a glycoprotein, CD4) on T cells. Primary strategies to prevent and treat HIV infection is to develop therapies (e.g., neutralizing antibodies) that can block specific binding of CD4 with gp120. The infection often leads to the lower counts of CD4 cells, which makes it an effective biomarker to monitor the AIDS progression and treatment. Despite research over decades, quantitative assays for effective measurements of binding affinities of protein-protein (ligand-receptor, antigen-antibody) interactions remains highly sought. Solid-phase electrochemiluminescence (ECL) immunoassay has been commonly used to capture analytes from the solution for analysis, which involves immobilization of antibody on solid surfaces (micron-sized beads), but it cannot quantitatively measure binding affinities of molecular interactions. In this study, we have developed solution-phase ECL assay with a wide dynamic range (0–2 nM) and high sensitivity and specificity for quantitative analysis of CD4 at femtomolar level and their binding affinity with gp120 and monoclonal antibodies (MABs). We found that binding affinities of CD4 with gp120 and MAB (Q4120) are 9.5×108 and 1.2×109 M−1, respectively. The results also show that MAB (Q4120) of CD4 can completely block the binding of gp120 with CD4, while MAB (17b) of gp120 can only partially block their interaction. This study demonstrates that the solution-phase ECL assay can be used for ultrasensitive and quantitative analysis of binding affinities of protein-protein interactions in solution for better understating of protein functions and identification of effective therapies to block their interactions. PMID:23565071

  5. Solid-solid phase transitions via melting in metals.

    PubMed

    Pogatscher, S; Leutenegger, D; Schawe, J E K; Uggowitzer, P J; Löffler, J F

    2016-04-22

    Observing solid-solid phase transitions in-situ with sufficient temporal and spatial resolution is a great challenge, and is often only possible via computer simulations or in model systems. Recently, a study of polymeric colloidal particles, where the particles mimic atoms, revealed an intermediate liquid state in the transition from one solid to another. While not yet observed there, this finding suggests that such phenomena may also occur in metals and alloys. Here we present experimental evidence for a solid-solid transition via the formation of a metastable liquid in a 'real' atomic system. We observe this transition in a bulk glass-forming metallic system in-situ using fast differential scanning calorimetry. We investigate the corresponding transformation kinetics and discuss the underlying thermodynamics. The mechanism is likely to be a feature of many metallic glasses and metals in general, and may provide further insight into phase transition theory.

  6. Solid-solid phase transitions via melting in metals

    NASA Astrophysics Data System (ADS)

    Pogatscher, S.; Leutenegger, D.; Schawe, J. E. K.; Uggowitzer, P. J.; Löffler, J. F.

    2016-04-01

    Observing solid-solid phase transitions in-situ with sufficient temporal and spatial resolution is a great challenge, and is often only possible via computer simulations or in model systems. Recently, a study of polymeric colloidal particles, where the particles mimic atoms, revealed an intermediate liquid state in the transition from one solid to another. While not yet observed there, this finding suggests that such phenomena may also occur in metals and alloys. Here we present experimental evidence for a solid-solid transition via the formation of a metastable liquid in a `real' atomic system. We observe this transition in a bulk glass-forming metallic system in-situ using fast differential scanning calorimetry. We investigate the corresponding transformation kinetics and discuss the underlying thermodynamics. The mechanism is likely to be a feature of many metallic glasses and metals in general, and may provide further insight into phase transition theory.

  7. Solid phase sequencing of biopolymers

    SciTech Connect

    Cantor, Charles R.; Hubert, Koster

    2014-06-24

    This invention relates to methods for detecting and sequencing target nucleic acid sequences, to mass modified nucleic acid probes and arrays of probes useful in these methods, and to kits and systems which contain these probes. Useful methods involve hybridizing the nucleic acids or nucleic acids which represent complementary or homologous sequences of the target to an array of nucleic acid probes. These probes comprise a single-stranded portion, an optional double-stranded portion and a variable sequence within the single-stranded portion. The molecular weights of the hybridized nucleic acids of the set can be determined by mass spectroscopy, and the sequence of the target determined from the molecular weights of the fragments. Probes may be affixed to a solid support such as a hybridization chip to facilitate automated molecular weight analysis and identification of the target sequence.

  8. Solid phase sequencing of biopolymers

    DOEpatents

    Cantor, Charles; Koster, Hubert

    2010-09-28

    This invention relates to methods for detecting and sequencing target nucleic acid sequences, to mass modified nucleic acid probes and arrays of probes useful in these methods, and to kits and systems which contain these probes. Useful methods involve hybridizing the nucleic acids or nucleic acids which represent complementary or homologous sequences of the target to an array of nucleic acid probes. These probes comprise a single-stranded portion, an optional double-stranded portion and a variable sequence within the single-stranded portion. The molecular weights of the hybridized nucleic acids of the set can be determined by mass spectroscopy, and the sequence of the target determined from the molecular weights of the fragments. Nucleic acids whose sequences can be determined include DNA or RNA in biological samples such as patient biopsies and environmental samples. Probes may be fixed to a solid support such as a hybridization chip to facilitate automated molecular weight analysis and identification of the target sequence.

  9. Solid-liquid phase transition in argon

    NASA Technical Reports Server (NTRS)

    Tsang, T.; Tang, H. T.

    1978-01-01

    Starting from the Lennard-Jones interatomic potential, a modified cell theory has been used to describe the solid-liquid phase transition in argon. The cell-size variations may be evaluated by a self-consistent condition. With the inclusion of cell-size variations, the transition temperature, the solid and liquid densities, and the liquid-phase radial-distribution functions have been calculated. These ab initio results are in satisfactory agreement with molecular-dynamics calculations as well as experimental data on argon.

  10. Solid-Solid Phase Transition Kinetics of FOX-7

    SciTech Connect

    Burnham, A K; Weese, R K; Wang, R; Kwok, Q M; Jones, D G

    2005-07-12

    Since it was developed in the late 1990s, 1,1-diamino-2,2-dinitroethene (FOX-7), with lower sensitivity and comparable performance to RDX, has received increasing interest. This paper will present our results for the phase changes of FOX-7 using DSC and HFC (Heat Flow Calorimetry). DSC thermal curves recorded at linear heating rates of 0.10, 0.35 and 1.0 C min{sup -1} show two endothermic peaks and two exothermic peaks. The two endothermic peaks represent solid-solid phase transitions, which have been observed in the literature at 114 C ({beta}-{gamma}) and 159 C ({gamma}-{delta}) by both DSC and XPD (X-ray powder diffraction) measurements. The first transition shifts from 114.5 to 115.8 C as the heating rate increases from 0.10 to 1.0 C min{sup -1}, while the second transition shifts from 158.5 to 160.4 C. Cyclical heating experiments show the endotherms and exotherms for a first heating through the {gamma} phase to the {delta} phase, a cooling and reversion to the {alpha} or {beta} phase, and a second heating to the {gamma} and {delta} phases. The data are interpreted using kinetic models with thermodynamic constraints.

  11. Solid-phase fermentation of sweet sorghum

    SciTech Connect

    Bryan, W.L.; Parrish, R.L.

    1982-12-01

    Solid-phase fermentations of chopped Wray sweet sorghum, (0.6 and 2.5 cm size) occurred in 7-liter fermentors at higher rates than juice fermentations and produced 80% ethanol yields, compared to 73% for juice. Heat loss from fermentors limited maximum temperatures to 38 degrees C. Low ethanol yields may have been caused by natural inhibitors or by thermal inhibition.

  12. Multiplexed Colorimetric Solid-Phase Extraction

    NASA Technical Reports Server (NTRS)

    Gazda, Daniel B.; Fritz, James S.; Porter, Marc D.

    2009-01-01

    Multiplexed colorimetric solid-phase extraction (MC-SPE) is an extension of colorimetric solid-phase extraction (C-SPE) an analytical platform that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water. In CSPE, analytes are extracted and complexed on the surface of an extraction membrane impregnated with a colorimetric reagent. The analytes are then quantified directly on the membrane surface using a handheld diffuse reflectance spectrophotometer. Importantly, the use of solid-phase extraction membranes as the matrix for impregnation of the colorimetric reagents creates a concentration factor that enables the detection of low concentrations of analytes in small sample volumes. In extending C-SPE to a multiplexed format, a filter holder that incorporates discrete analysis channels and a jig that facilitates the concurrent operation of multiple sample syringes have been designed, enabling the simultaneous determination of multiple analytes. Separate, single analyte membranes, placed in a readout cartridge create unique, analyte-specific addresses at the exit of each channel. Following sample exposure, the diffuse reflectance spectrum of each address is collected serially and the Kubelka-Munk function is used to quantify each water quality parameter via calibration curves. In a demonstration, MC-SPE was used to measure the pH of a sample and quantitate Ag(I) and Ni(II).

  13. Astronomical observations of solid phase carbon

    NASA Technical Reports Server (NTRS)

    Jura, M.

    1990-01-01

    In the outer envelopes of red giants, when the gas cools sufficiently, molecules and solids form. Thermodynamically, the most stable molecule is CO, and it is usually assumed that all the available carbon and oxygen are consumed in the formation of this molecule (Salpeter 1977). If the carbon abundance is greater than the oxygen abundance, then the carbon left over after the formation of CO is available for solid grains. Because carbon is by far the most abundant species available for making solids in these environments, researchers anticipate that the grains are composed of nearly pure carbon in some form. The observations which can be used to infer the nature of this solid phase carbon are discussed. The observations of the dust around carbon-rich red giants are discussed. These results are then placed into their broader astrophysical context.

  14. Directed evolution and solid phase enzyme screening

    NASA Astrophysics Data System (ADS)

    Bylina, Edward J.; Grek, Christina L.; Coleman, William J.; Youvan, Douglas C.

    2000-03-01

    A new digital imaging spectrophotometer and a series of colorimetric solid phase arrays have been developed to screen bacterial libraries expressing mutagenized enzymes undergoing directed evolution. This high-throughput solid- phase array system (known as `Kcat Technology') can detect less than a 20% difference in enzyme rates within microcolonies grown at a nearly confluent density of 500 colonies per cm2 on an assay disk. Each microcolony is analyzed simultaneously at single-pixel resolution (1.5 megapixels; 75 micron/pixel), requiring less than 100 nanoliters of substrate per measurement, a 1000-fold reduction over conventional liquid phase assays. Here we report the successful identification of variants of Agrobacterium (beta) -glucosidase--a glycosidase with broad substrate specificity that favors cleavage of glucosides over galactosides--by simultaneously assaying two different substrates tagged with spectrally distinct chromogenic reporters.

  15. Solid-phase synthesis of prenylcysteine analogs

    PubMed Central

    Donelson, James L.; Hodges-Loaiza, Heather B.; Henriksen, Brian S.; Hrycyna, Christine A.

    2009-01-01

    Prenylcysteine derivatives are of interest for a variety of different biological reasons, including probing the CaaX protein processing pathway. A solid-phase synthesis protocol for the preparation of prenylcysteines using 2-chlorotrityl chloride resin as a solid support has been developed. A series of novel amide-modified farnesylcysteine analogs were synthesized in both high purity and yield under mild conditions. The farnesylcysteine analogs were evaluated using human isoprenylcysteine carboxyl methyltransferase (Icmt) as a biological target, and several new inhibitors, one with significantly enhanced potency, were identified. PMID:19320430

  16. Solid-phase fermentation of sweet sorghum

    SciTech Connect

    Bryan, W.L.; Parrish, R.L.

    1982-12-01

    Solid-phase fermentations of chopped Wray sweet sorghum, (0.6 and 2.5 cm size) occurred in 7-liter fermentors at higher rates than juice fermentations and produced 80% ethanol yields, compared to 73% for juice. Heat loss from fermentors limited maximum temperatures to 38/sup 0/C. Low ethanol yields may have been caused by natural inhibitors or by thermal inhibition.

  17. [Solid phase techniques in blood group serology].

    PubMed

    Uthemann, H; Sturmfels, L; Lenhard, V

    1993-06-01

    As alternatives to hemagglutination, solid-phase red blood cell adherence assays are of increasing importance. The adaptation of the new techniques to microplates offers several advantages over hemagglutination. Using microplates the assays may be processed semiautomatically, and the results can be read spectrophotometrically and interpreted by a personal computer. In this paper, different red blood cell adherence assays for AB0 grouping, Rh typing, Rh phenotyping, antibody screening and identification, as well as crossmatching will be described.

  18. Solid-state dimer method for calculating solid-solid phase transitions

    SciTech Connect

    Xiao, Penghao; Henkelman, Graeme; Sheppard, Daniel; Rogal, Jutta

    2014-05-07

    The dimer method is a minimum mode following algorithm for finding saddle points on a potential energy surface of atomic systems. Here, the dimer method is extended to include the cell degrees of freedom for periodic solid-state systems. Using this method, reaction pathways of solid-solid phase transitions can be determined without having to specify the final state structure or reaction mechanism. Example calculations include concerted phase transitions between CdSe polymorphs and a nucleation and growth mechanism for the A15 to BCC transition in Mo.

  19. A liquid phase affinity capture assay using magnetic beads to study protein-protein interaction: the poliovirus-nanobody example.

    PubMed

    Schotte, Lise; Rombaut, Bart; Thys, Bert

    2012-05-29

    In this article, a simple, quantitative, liquid phase affinity capture assay is presented. Provided that one protein can be tagged and another protein labeled, this method can be implemented for the investigation of protein-protein interactions. It is based on one hand on the recognition of the tagged protein by cobalt coated magnetic beads and on the other hand on the interaction between the tagged protein and a second specific protein that is labeled. First, the labeled and tagged proteins are mixed and incubated at room temperature. The magnetic beads, that recognize the tag, are added and the bound fraction of labeled protein is separated from the unbound fraction using magnets. The amount of labeled protein that is captured can be determined in an indirect way by measuring the signal of the labeled protein remained in the unbound fraction. The described liquid phase affinity assay is extremely useful when conformational conversion sensitive proteins are assayed. The development and application of the assay is demonstrated for the interaction between poliovirus and poliovirus recognizing nanobodies(1). Since poliovirus is sensitive to conformational conversion(2) when attached to a solid surface (unpublished results), the use of ELISA is limited and a liquid phase based system should therefore be preferred. An example of a liquid phase based system often used in polioresearch(3,4) is the micro protein A-immunoprecipitation test(5). Even though this test has proven its applicability, it requires an Fc-structure, which is absent in the nanobodies(6,7). However, as another opportunity, these interesting and stable single-domain antibodies(8) can be easily engineered with different tags. The widely used (His)(6)-tag shows affinity for bivalent ions such as nickel or cobalt, which can on their turn be easily coated on magnetic beads. We therefore developed this simple quantitative affinity capture assay based on cobalt coated magnetic beads. Poliovirus was labeled

  20. Kinetics of Solid-Solid Phase Transition in Iron (u)

    SciTech Connect

    Schwartz, Cynthia, L

    2011-01-27

    Previously, dynamic experiments on iron have observed a non-zero transition time and width in the solid-solid {alpha}-{var_epsilon} phase transition. Using Proton Radiography at the los Alamos Neutron Science Center, we have performed plate impact experiments on iron to further study the {alpha}-{var_epsilon} phase transition which occurs at 13GPa. A 40mm bore powder gun was coupled to a proton radiography beam line and imaging system and synchronized to the impact of the projectile on the target sample with the proton beam pattern. A typical experimental configuration for the iron study, as shown below in 3 color-enhanced radiographs, is a 40mm diameter aluminum sabot impacting a 40mm diameter of polycrystalline ARMCO iron. The iron is backed by a sapphire optical window for velocimetry measurements. The aluminum flyer on the left of the iron is barely visible for visual display purposes. Direct density jumps were measured which corresponded to calculations to within 1% using a Wondy multi-phase equation of state model. In addition, shock velocities were measured using an edge fitting technique and followed that edge movement from radiograph to radiograph, where rad iographs are separated in time by 500 ns. Preliminary measurements give a shock velocity (P1 wave) of 5.251 km/s. The projectile velocity was 0.725 km/s which translate to a peak stress of 17.5 GPa. Assuming the P1 wave is instantaneous, we are able to calibrate the chromatic, motion, object and camera blur by measuring the width of the P1 wave. This approximation works in this case since each of the two density jumps are small compared to the density of the object. Subtracting the measured width of the P1 wave in quadrature from the width of the P2 wave gives a preliminary measurement of the transition length of 265 {micro}m. Therefore, a preliminary measured phase transition relaxation time {tau} = transition length/u{sub s} = 265 {micro}m/5.251 km/s = 50 ns. Both Boettger1 & Jensen2 conclude that

  1. Solid-state phased array (SSPA) performance

    NASA Astrophysics Data System (ADS)

    Kley, Robert C., Jr.; Hull, W. Porter, Jr.; Lamb, Franklin D.

    The solid-state phased-array (SSPA) is an active electronically scanned array (AESA) designed and built for airborne radar applications using transmit/receive module hybrid technology. Details of its subassemblies and results of testing the array and its subassemblies are presented. The SSPA T/R (transmit/receive) modules used a hybrid construction that is labor-intensive and leads to parameter variations. The next generation of modules uses monolithic microwave integrated circuit (MMIC) devices, which will result in more uniform parameters and lower manufacturing cost.

  2. Solid drop based liquid-phase microextraction.

    PubMed

    Ganjali, Mohammad Reza; Sobhi, Hamid Reza; Farahani, Hadi; Norouzi, Parviz; Dinarvand, Rassoul; Kashtiaray, Amir

    2010-04-16

    Solid drop based liquid-phase microextraction (SDLPME) is a novel sample preparation technique possessing obvious advantages of simple operation with a high pre-concentration factor, low cost and low consumption of organic solvent. SDLPME coupled with gas chromatography (GC), high-performance liquid chromatography (HPLC), and atomic absorption spectrometry (AAS) has been widely applied to the analyses of a different variety of samples. The basic principles, parameters affecting the extraction efficiency, and the latest applications of SDLPME are reviewed in this article. PMID:19962710

  3. Unification of radar phenomena as spacetime curvature: prediction and observation of an affine-phase effect.

    PubMed

    Gabriel, Andrew K

    2004-07-01

    The many properties of radar echoes and other radiative systems were recently described by Gabriel [J. Opt. Soc. Am. A 19, 946 (2002)] as lower-dimensional projections of simple forms in special relativity. A broader treatment including coherent phenomena is summarized, in which the phase properties of radar images and interferograms are also shown to have a simple unified structure. Their apparent complexity is a result of projection onto the lower dimension(s) of the observation. A predicted new property, locally scalable (affine) phase, is observed in a radar interferogram. PMID:15259737

  4. Solid-phase extraction in segmented flow.

    PubMed

    Rendl, Martin; Brandstetter, Thomas; Rühe, Jürgen

    2014-11-01

    Two-phase flow systems are increasingly popular for miniaturized, high-throughput performance of analytical or chemical reactions. In this contribution, we extend a previously described method that allows to increase the range of applications of heterogeneous reactions in two-phase flow, i.e., reactions that rely on isolation and purification of the compound of interest for downstream analysis. Our concept is based on liquid plugs, which serve as miniaturized compartments for the analytical reactions. Purification of the target compound is achieved by extracting the analyte from the aqueous compartments using magnetic beads as solid carriers. In the present paper, we elucidate the influence of parameters such as the polarity of the liquid/liquid and solid/liquid interfaces, the magnetic forces and the fluidic conditions onto the extraction performance. The conditions for reliable extraction and purification of the target compounds are determined. Furthermore, we investigate how to facilitate breaking of the plugs through reduction of the surface tension of the solid/liquid interface. When a lower surface tension is employed, a smaller number of beads is required for the extraction process, which implies a higher sensitivity of the device. In addition, we generate channels with different surface chemistries, which are able to manipulate the flow of the two immiscible liquids. We describe a very simple way to generate such devices and show that we can achieve a transition from segmented flow of plugs to a side-by side flow of the two immiscible liquids, a key requirement for the purification of the compounds. PMID:25300748

  5. Biotin-functionalized poly(ethylene terephthalate) capillary-channeled polymer fibers as HPLC stationary phase for affinity chromatography.

    PubMed

    Jiang, Liuwei; Marcus, R Kenneth

    2015-01-01

    Native poly(ethylene terephthalate) (PET) capillary-channeled polymer (C-CP) fibers have been used as the stationary phase for high-performance liquid chromatography (HPLC) of proteins via reversed-phase and ion-exchange processes. Functionalization can be used to bring about greater selectivity through surface modification. PET fibers were treated with ethylenediamine to generate primary amine groups on the fiber surface, enabling subsequent covalent attachment of ligands. The ninhydrin test for primary amines revealed surface densities of 13.9-60.0 μmol m(-2) for PET fibers exposed for periods of 3-12 min. Here, 8-amino-3,6-dioxaoctanoic acid was linked to the EDA-treated PET fiber surface as a hydrophilic spacer, and then D-biotin was attached on the end of the spacer as an affinity ligand. The streptavidin binding capacity and binding homogeneity were studied on the biotin-functionalized PET C-CP fiber microbore column. The selectivity of the biotin surface functionalization was assessed by spiking lysate with Texas Red-labeled streptavidin and enhanced green fluorescent protein. Greater than 99% selectivity was realized. This ligand-coupling strategy from standard solid-phase peptide synthesis used in stationary phase functionalization creates great potential for PET C-CP fiber-packed HPLC columns to perform a variety of chromatographic separations. PMID:25410640

  6. Solid-phase glycan isolation for glycomics analysis

    PubMed Central

    Yang, Shuang; Zhang, Hui

    2013-01-01

    Glycosylation is one of the most significant protein PTMs. The biological activities of proteins are dramatically changed by the glycans associated with them. Thus, structural analysis of the glycans of glycoproteins in complex biological or clinical samples is critical in correlation with the functions of glycans with diseases. Profiling of glycans by HPLC-MS is a commonly used technique in analyzing glycan structures and quantifying their relative abundance in different biological systems. Methods relied on MS require isolation of glycans from negligible salts and other contaminant ions since salts and ions may interfere with the glycans, resulting in poor glycan ionization. To accomplish those objectives, glycan isolation and clean-up methods including SPE, liquid-phase extraction, chromatography, and electrophoresis have been developed. Traditionally, glycans are isolated from proteins or peptides using a combination of hydrophobic and hydrophilic columns: proteins and peptides remain on hydrophobic absorbent while glycans, salts, and other hydrophilic reagents are collected as flowthrough. The glycans in the flowthrough are then purified through graphite-activated carbon column by hydrophilic interaction LC. Yet, the drawback in these affinity-based approaches is nonspecific binding. As a result, chemical methods by hydrazide or oxime have been developed for solid-phase isolation of glycans with high specificity and yield. Combined with high-resolution MS, specific glycan isolation techniques provide tremendous potentials as useful tools for glycomics analysis. PMID:23090885

  7. Solvent-assisted dispersive solid phase extraction.

    PubMed

    Jamali, Mohammad Reza; Firouzjah, Ahmad; Rahnama, Reyhaneh

    2013-11-15

    In this research, a novel extraction technique termed solvent-assisted dispersive solid phase extraction (SADSPE) was developed for the first time. The new method was based on the dispersion of the sorbent into the sample to maximize the contact surface. In this method, the dispersion of the sorbent at a very low milligram level was achieved by injecting a solution of the sorbent into the aqueous sample. Thereby, a cloudy solution formed. The cloudy state resulted from the dispersion of the fine particles of the sorbent in the bulk aqueous sample. After extraction, phase separation was performed by centrifugation and the enriched analyte in the sedimented phase could be determined by instrumental methods. The performance of SADSPE was illustrated with the determination of the trace amounts of cobalt(II) as a test analyte in food and environmental water samples by using flame atomic absorption spectrometry detection. Some key parameters for SADSPE, such as sorbent selection and amount, type and volume of dispersive solvent, pH, chelating agent concentration, and salt concentration, were investigated. Under the most favorable conditions, good limit of detection (as low as 0.2 µg L(-1)) and repeatability of extraction (RSD below 2.2%, n=10) was obtained. The accuracy of the method was tested with standard reference material (SRM-1643e and SRM-1640a) and spiked addition. The advantages of SADSPE method are simplicity of operation, rapidity, low cost, high recovery, and enrichment factor. PMID:24148429

  8. Solid phase microextraction device using aerogel

    DOEpatents

    Miller, Fred S.; Andresen, Brian D.

    2005-06-14

    A sample collection substrate of aerogel and/or xerogel materials bound to a support structure is used as a solid phase microextraction (SPME) device. The xerogels and aerogels may be organic or inorganic and doped with metals or other compounds to target specific chemical analytes. The support structure is typically formed of a glass fiber or a metal wire (stainless steel or kovar). The devices are made by applying gel solution to the support structures and drying the solution to form aerogel or xerogel. Aerogel particles may be attached to the wet layer before drying to increase sample collection surface area. These devices are robust, stable in fields of high radiation, and highly effective at collecting gas and liquid samples while maintaining superior mechanical and thermal stability during routine use. Aerogel SPME devices are advantageous for use in GC/MS analyses due to their lack of interfering background and tolerance of GC thermal cycling.

  9. Offline solid phase microextraction sampling system

    DOEpatents

    Harvey, Chris A.

    2008-12-16

    An offline solid phase microextraction (SPME) sampling apparatus for enabling SPME samples to be taken a number of times from a previously collected fluid sample (e.g. sample atmosphere) stored in a fused silica lined bottle which keeps volatile organics in the fluid sample stable for weeks at a time. The offline SPME sampling apparatus has a hollow body surrounding a sampling chamber, with multiple ports through which a portion of a previously collected fluid sample may be (a) released into the sampling chamber, (b) SPME sampled to collect analytes for subsequent GC analysis, and (c) flushed/purged using a fluidically connected vacuum source and purging fluid source to prepare the sampling chamber for additional SPME samplings of the same original fluid sample, such as may have been collected in situ from a headspace.

  10. Improvement of solid material for affinity resins by application of long PEG spacers to capture the whole target complex of FK506.

    PubMed

    Mabuchi, Miyuki; Shimizu, Tadashi; Ueda, Masahiro; Mitamura, Kuniko; Ikegawa, Shigeo; Tanaka, Akito

    2015-07-15

    Solid materials for affinity resins bearing long PEG spacers between a functional group used for immobilization of a bio-active compound and the solid surface were synthesized to capture not only small target proteins but also large and/or complex target proteins. Solid materials with PEG1000 or PEG2000 as spacers, which bear a benzenesulfonamide derivative, exhibited excellent selectivity between the specific binding protein carbonic anhydrase type II (CAII) and non-specific ones. These materials also exhibited efficacy in capturing a particular target at a maximal amount. Affinity resins using solid materials with PEG1000 or PEG2000 spacers, bear a FK506 derivative, successfully captured the whole target complex of specific binding proteins at the silver staining level, while all previously known affinity resins with solid materials failed to achieve this objective. These novel affinity resins captured other specific binding proteins such as dynamin and neurocalcin δ as well. PMID:26025877

  11. Automated solid-phase peptide synthesis to obtain therapeutic peptides

    PubMed Central

    Mäde, Veronika; Els-Heindl, Sylvia

    2014-01-01

    Summary The great versatility and the inherent high affinities of peptides for their respective targets have led to tremendous progress for therapeutic applications in the last years. In order to increase the drugability of these frequently unstable and rapidly cleared molecules, chemical modifications are of great interest. Automated solid-phase peptide synthesis (SPPS) offers a suitable technology to produce chemically engineered peptides. This review concentrates on the application of SPPS by Fmoc/t-Bu protecting-group strategy, which is most commonly used. Critical issues and suggestions for the synthesis are covered. The development of automated methods from conventional to essentially improved microwave-assisted instruments is discussed. In order to improve pharmacokinetic properties of peptides, lipidation and PEGylation are described as covalent conjugation methods, which can be applied by a combination of automated and manual synthesis approaches. The synthesis and application of SPPS is described for neuropeptide Y receptor analogs as an example for bioactive hormones. The applied strategies represent innovative and potent methods for the development of novel peptide drug candidates that can be manufactured with optimized automated synthesis technologies. PMID:24991269

  12. Recent developments in solid-phase microextraction.

    PubMed

    Risticevic, Sanja; Niri, Vadoud H; Vuckovic, Dajana; Pawliszyn, Janusz

    2009-02-01

    The main objective of this review is to describe the recent developments in solid-phase microextraction technology in food, environmental and bioanalytical chemistry applications. We briefly introduce the historical perspective on the very early work associated with the development of theoretical principles of SPME, but particular emphasis is placed on the more recent developments in the area of automation, high-throughput analysis, SPME method optimization approaches and construction of new SPME devices and their applications. The area of SPME automation for both GC and LC applications is particularly addressed in this review, as the most recent developments in this field have allowed the use of this technology for high-throughput applications. The development of new autosamplers with SPME compatibility and new-generation metal fibre assemblies has enhanced sample throughput for SPME-GC applications, the latter being attributed to the possibility of using the same fibre for several hundred extraction/injection cycles. For LC applications, high-throughput analysis (>1,000 samples per day) can be achieved for the first time with a multi-SPME autosampler which uses multi-well plate technology and allows SPME sample preparation of up to 96 samples in parallel. The development and evolution of new SPME devices such as needle trap, thin-film microextraction and cold-fibre headspace SPME have offered significant improvements in performance characteristics compared with the conventional fibre-SPME arrangement.

  13. Preparation of Ion Exchange Films for Solid-Phase Spectrophotometry and Solid-Phase Fluorometry

    NASA Technical Reports Server (NTRS)

    Hill, Carol M.; Street, Kenneth W.; Tanner, Stephen P.; Philipp, Warren H.

    2000-01-01

    Atomic spectroscopy has dominated the field of trace inorganic analysis because of its high sensitivity and selectivity. The advantages gained by the atomic spectroscopies come with the disadvantage of expensive and often complicated instrumentation. Solid-phase spectroscopy, in which the analyte is preconcentrated on a solid medium followed by conventional spectrophotometry or fluorometry, requires less expensive instrumentation and has considerable sensitivity and selectivity. The sensitivity gains come from preconcentration and the use of chromophore (or fluorophore) developers and the selectivity is achieved by use of ion exchange conditions that favor the analyte in combination with speciative chromophores. Little work has been done to optimize the ion exchange medium (IEM) associated with these techniques. In this report we present a method for making ion exchange polymer films, which considerably simplify the solid-phase spectroscopic techniques. The polymer consists of formaldehyde-crosslinked polyvinyl alcohol with polyacrylic acid entrapped therein. The films are a carboxylate weak cation exchanger in the calcium form. They are mechanically sturdy and optically transparent in the ultraviolet and visible portion of the spectrum, which makes them suitable for spectrophotometry and fluorometry.

  14. Air sampling with solid phase microextraction

    NASA Astrophysics Data System (ADS)

    Martos, Perry Anthony

    There is an increasing need for simple yet accurate air sampling methods. The acceptance of new air sampling methods requires compatibility with conventional chromatographic equipment, and the new methods have to be environmentally friendly, simple to use, yet with equal, or better, detection limits, accuracy and precision than standard methods. Solid phase microextraction (SPME) satisfies the conditions for new air sampling methods. Analyte detection limits, accuracy and precision of analysis with SPME are typically better than with any conventional air sampling methods. Yet, air sampling with SPME requires no pumps, solvents, is re-usable, extremely simple to use, is completely compatible with current chromatographic equipment, and requires a small capital investment. The first SPME fiber coating used in this study was poly(dimethylsiloxane) (PDMS), a hydrophobic liquid film, to sample a large range of airborne hydrocarbons such as benzene and octane. Quantification without an external calibration procedure is possible with this coating. Well understood are the physical and chemical properties of this coating, which are quite similar to those of the siloxane stationary phase used in capillary columns. The log of analyte distribution coefficients for PDMS are linearly related to chromatographic retention indices and to the inverse of temperature. Therefore, the actual chromatogram from the analysis of the PDMS air sampler will yield the calibration parameters which are used to quantify unknown airborne analyte concentrations (ppb v to ppm v range). The second fiber coating used in this study was PDMS/divinyl benzene (PDMS/DVB) onto which o-(2,3,4,5,6- pentafluorobenzyl) hydroxylamine (PFBHA) was adsorbed for the on-fiber derivatization of gaseous formaldehyde (ppb v range), with and without external calibration. The oxime formed from the reaction can be detected with conventional gas chromatographic detectors. Typical grab sampling times were as small as 5 seconds

  15. Solid-solid phase transitions determined by differential scanning calorimetry.

    NASA Technical Reports Server (NTRS)

    Murrill, E.; Whitehead, M. E.; Breed, L.

    1972-01-01

    Data are presented to show that tris(hydroxymethyl)acetic acid, monochloropentaerythritol, monofluoropentaerythritol, difluoropentaerythritol, monoaminopentaerythritol, and diaminopentaerythritol exhibit solid-state transitions to a plastic crystalline state. Transitional enthalpies in many of these substances are lower than might be expected by analogy with related structures, suggesting that some configurational contributions to their entropy increments have been inhibited.

  16. Affinity Selection of Peptide Binders with Magnetic Beads via Organic Phase Separation (MOPS).

    PubMed

    Murai, Ryuichi; Nogi, Taiki; Tateoka, Komei; Sato, Atsushi

    2015-01-01

    We describe a new method for affinity selection of peptide binders for soluble protein targets using magnetic beads via organic phase separation (MOPS) from a phage display library. As a model target molecule, a mouse monoclonal antibody against human integrin α9β1 (Y9A2) immobilized onto protein G magnetic beads was incubated with a 15-mer or 20-mer random peptide phage-display library. The suspensions containing the phage-magnetic beads conjugates were then transferred onto the organic phase and centrifuged in order to recover the Y9A2 bound phage immobilized on the protein G magnetic beads in the lower organic phase. After three rounds of biopanning, we were able to isolate specific phage clones that could not be obtained by the conventional approach. Furthermore, this new approach was found to be highly effective for isolating phage-binders for Fc-fusion constructs; indeed, enrichment of specific phage-binders was observed after only the first panning cycle. Thus, MOPS can improve the selection of specific phage-binders for soluble protein targets mainly due to the removal of non-specific binders.

  17. Crystal-Phase Control by Solution-Solid-Solid Growth of II-VI Quantum Wires.

    PubMed

    Wang, Fudong; Buhro, William E

    2016-02-10

    A simple and potentially general means of eliminating the planar defects and phase alternations that typically accompany the growth of semiconductor nanowires by catalyzed methods is reported. Nearly phase-pure, defect-free wurtzite II-VI semiconductor quantum wires are grown from solid rather than liquid catalyst nanoparticles. The solid-catalyst nanoparticles are morphologically stable during growth, which minimizes the spontaneous fluctuations in nucleation barriers between zinc blende and wurtzite phases that are responsible for the defect formation and phase alternations. Growth of single-phase (in our cases the wurtzite phase) nanowires is thus favored. PMID:26731426

  18. Solid lubrication design methodology, phase 2

    NASA Technical Reports Server (NTRS)

    Pallini, R. A.; Wedeven, L. D.; Ragen, M. A.; Aggarwal, B. B.

    1986-01-01

    The high temperature performance of solid lubricated rolling elements was conducted with a specially designed traction (friction) test apparatus. Graphite lubricants containing three additives (silver, phosphate glass, and zinc orthophosphate) were evaluated from room temperature to 540 C. Two hard coats were also evaluated. The evaluation of these lubricants, using a burnishing method of application, shows a reasonable transfer of lubricant and wear protection for short duration testing except in the 200 C temperature range. The graphite lubricants containing silver and zinc orthophosphate additives were more effective than the phosphate glass material over the test conditions examined. Traction coefficients ranged from a low of 0.07 to a high of 0.6. By curve fitting the traction data, empirical equations for slope and maximum traction coefficient as a function of contact pressure (P), rolling speed (U), and temperature (T) can be developed for each lubricant. A solid lubricant traction model was incorporated into an advanced bearing analysis code (SHABERTH). For comparison purposes, preliminary heat generation calculations were made for both oil and solid lubricated bearing operation. A preliminary analysis indicated a significantly higher heat generation for a solid lubricated ball bearing in a deep groove configuration. An analysis of a cylindrical roller bearing configuration showed a potential for a low friction solid lubricated bearing.

  19. The two solid phases of chlorodifluoromethane

    NASA Astrophysics Data System (ADS)

    Binbrek, O. S.; Torrie, B. H.; von Dreele, R.; Powelle, B. M.

    The crystal structure of the two phases of chlorodifluoromethane (CHClF ) were determined at 70 K and 10 K using Rietveld refinement of neutron powder profiles. The upper phase is tetragonal P4 on (C ) with eight molecules in the unit cell occupying general positions. The h lattice constants are a 10 3711(1) A and c 5 5915(2) A. The lower phase is monoclinic P112on (C ) with eight molecules in the unit cell with dimensions a 10 1106(2), b h 10 4830(2), c 5 5868(2) A and gamma 90 319(2) . The asymmetric unit has two molecules in general positions. The phase transition is of a displacive type but there are no large changes in the molecular positions or orientations at the transition.

  20. Novel cross-linked alcohol-insoluble solid (CL-AIS) affinity gel from pea pod for pectinesterase purification.

    PubMed

    Wu, Ming-Chang; Lin, Guan-Hui; Wang, Yuh-Tai; Jiang, Chii-Ming; Chang, Hung-Min

    2005-10-01

    Alcohol-insoluble solids (AIS) from pea pod were cross-linked (CL-AIS) and used as an affinity gel matrix to isolate pectin esterases (PEs) from tendril shoots of chayote (TSC) and jelly fig achenes (JFA), and the results were compared with those isolated by ion-exchange chromatography with a commercial resin. CL-AIS gel matrix in a column displayed poor absorption and purification fold of PE; however, highly methoxylated CL-AIS (HM-CL-AIS), by exposing CL-AIS to methanolic sulfuric acid to increase the degree of esterification (DE) to 92%, facilitated the enzyme purification. The purified TSC PE and JFA PE by the HM-CL-AIS column were proofed as a single band on an SDS-PAGE gel, showing that the HM-CL-AIS column was a good matrix for purification of PE, either with alkaline isoelectric point (pI) (TSC PE) or with acidic pI (JFA PE).

  1. A fullerene C60-based ligand in a stationary phase for affine chromatography of membrane porphyrin-binding proteins

    NASA Astrophysics Data System (ADS)

    Amirshakhi, N.; Alyautdin, R. N.; Orlov, A. P.; Poloznikov, A. A.; Kuznetsov, D. A.

    2008-11-01

    A new affine chromatography technique is suggested for the purification of porphyrin-binding proteins (PBP) from mammal cell membranes. The procedure uses new fullerene-porphyrin ligands immobilized on agarose and bound to the polysaccharide matrix via the epoxycyclohexyl residue. A selective PBP stationary phase was used in a single-column chromatography run for the complete purification of a monomeric protein (17.6 kDa) from mitochondrial membranes of rat myocardium. This protein was characterized by high affinity for porphyrin-related structures. To separate it from other nonspecifically sorbed membrane proteins, synchronous linear pH and ionic strength gradients were used.

  2. Solid-liquid phase boundaries of lens protein solutions.

    PubMed Central

    Berland, C R; Thurston, G M; Kondo, M; Broide, M L; Pande, J; Ogun, O; Benedek, G B

    1992-01-01

    We report measurement of the solid-liquid phase boundary, or liquidus line, for aqueous solutions of three pure calf gamma-crystallin proteins: gamma II, gamma IIIa, and gamma IIIb. We also studied the liquidus line for solutions of native gamma IV-crystallin calf lens protein, which consists of 85% gamma IVa/15% gamma IVb. In all four proteins the liquidus phase boundaries lie higher in temperature than the previously determined liquid-liquid coexistence curves. Thus, over the range of concentration and temperature for which liquid-liquid phase separation occurs, the coexistence of a protein crystal phase with a protein liquid solution phase is thermodynamically stable relative to the metastable separated liquid phases. The location of the liquidus lines clearly divides these four crystallin proteins into two groups: those in which liquidus lines flatten at temperatures greater than 70 degrees C: gamma IIIa and gamma IV, and those in which liquidus lines flatten at temperatures less than 50 degrees C: gamma II and gamma IIIb. We have analyzed the form of the liquidus lines by using specific choices for the structures of the Gibbs free energy in solution and solid phases. By applying the thermodynamic conditions for equilibrium between the two phases to the resulting chemical potentials, we can estimate the temperature-dependent free energy change upon binding of protein and water into the solid phase. PMID:1741375

  3. High power phase conjugated solid state lasers

    SciTech Connect

    Hackel, L.A.; Dane, C.B.; Zapata, L.E.; Hermann, M.R.

    1994-07-01

    Three laser systems that are being developed for use in x-ray generation which incorporate SBS phase conjugate mirrors are described. A 25J/pulse Nd:glass laser is being developed for commercial proximity print x-ray lithography; a 0.5J/pulse, 1.3 kHz pulse repetition frequency laser is being built for soft x-ray projection lithography; and a 1 kJ/pulse laser driver for a table top x-ray laser has been designed. The results of prototypical experimental investigations are presented and the basic design principles for high average power phase conjugated laser systems shared by each of these lasers are discussed.

  4. Solid state photomultiplier for astronomy, phase 2

    NASA Technical Reports Server (NTRS)

    Besser, P. J.; Hays, K. M.; Laviolette, R. A.

    1989-01-01

    Epitaxial layers with varying donor concentration profiles were grown on silicon substrate wafers using chemical vapor deposition (CVD) techniques, and solid state photomultiplier (SSPM) devices were fabricated from the wafers. Representative detectors were tested in a low background photon flux, low temperature environment to determine the device characteristics for comparison to NASA goals for astronomical applications. The SSPM temperatures varied between 6 and 11 K with background fluxes in the range from less than 5 x 10 to the 6th power to 10 to the 13th power photons/square cm per second at wavelengths of 3.2 and 20 cm. Measured parameters included quantum efficiency, dark count rate and bias current. Temperature for optimal performance is 10 K, the highest ever obtained for SSPMs. The devices exhibit a combination of the lowest dark current and highest quantum efficiency yet achieved. Experimental data were reduced, analyzed and used to generate recommendations for future studies. The background and present status of the microscopic theory of SSPM operation were reviewed and summarized. Present emphasis is on modeling of the avalanche process which is the basis for SSPM operation. Approaches to the solution of the Boltzmann transport equation are described and the treatment of electron scattering mechanisms is presented. The microscopic single-electron transport theory is ready to be implemented for large-scale computations.

  5. Solid-phase techniques in blood transfusion serology.

    PubMed

    Beck, M L; Plapp, F V; Sinor, L T; Rachel, J M

    1986-01-01

    For nearly a century, erythrocyte agglutination has persisted as the most widely used method for the demonstration of antigen-antibody reaction in immunohematology. So far, no other system has been developed which can match its simplicity, versatility, and general reliability. The major disadvantage of agglutination reactions is the lack of an objective endpoint, which has severely hindered attempts to automate routine pretransfusion tests. To overcome this problem, we have designed a series of solid-phase assays for ABO and Rh grouping, antibody screening, compatibility, and hepatitis tests. Each of these solid-phase assays shares a common endpoint of red cell adherence, which is easily interpreted visually or spectrophotometrically. Computer interface permits the automatic interpretation and recording of results. We believe this solid-phase system should finally bring the blood bank laboratory into the age of automation.

  6. Recent developments in matrix solid-phase dispersion extraction.

    PubMed

    Capriotti, Anna Laura; Cavaliere, Chiara; Giansanti, Piero; Gubbiotti, Riccardo; Samperi, Roberto; Laganà, Aldo

    2010-04-16

    Matrix solid-phase dispersion is a sample preparation strategy widely applied to solid, semisolid or viscous samples, including animal tissues and foods with a high lipidic content. The process consists in blending the matrix onto a solid support, allowing the matrix cell disruption and the subsequent extraction of target analytes by means of a suitable elution solvent. First introduced in 1989, MSPD employment and developments are still growing because of the feasibility and versatility of the process, as evidenced by the several reviews that have been published since nineties. Therefore, the aim of the present review is to provide a general overview and an update of the last developments of MSPD.

  7. Molecularly imprinted hollow spheres for the solid phase extraction of estrogens.

    PubMed

    Chen, Wei; Xue, Min; Xue, Fei; Mu, Xiangrong; Xu, Zhibin; Meng, Zihui; Zhu, Guangxian; Shea, Kenneth J

    2015-08-01

    Solid phase extraction (SPE) is widely used in many different areas, such as environmental, biological, and food analysis, where cleaning and pre-concentration of samples are key steps in the analytical protocol. New materials have significant impact on the development of solid phase extraction. In this paper, mono-dispersed molecularly imprinted hollow spheres (MIHSs) of β-estradiol (E2) were synthesized using silica nanospheres particles as the sacrificial matrix. Compared to the corresponding non-imprinted hollow spheres (NIHSs), the MIHSs with uniform size of 290 nm have outstanding affinity in aqueous solution. Static saturation adsorption required only 15min to achieve equilibrium, with a binding capacity (Qmax) of 44.5 μmol g(-1). The extraction of E2, ethinyl estradiol (EE), diethylstilbestrol (DES), ethisterone (ES) and estrone (E1) from water samples by MIHSs was also investigated. In the spiked samples of tap water, Qinghe river water and Zhanjiang river water, more than 90.42% of E2, but less than 79% of EE, DES, ES and E1 were recovered. The limits of detection (LOD) ranged from 0.1 to 0.26 µmol L(-1) after solid phase extraction by MIHSs and HPLC-UV analysis. The adsorption capacity of the MIHSs showed no significant deterioration after six rounds of regeneration. PMID:26048825

  8. SOLID PHASE MICROEXTRACTION SAMPLING OF HIGH EXPLOSIVE RESIDUES IN THE PRESENCE OF RADIONUCLIDES AND RADIONUCLIDE SURROGATE METALS

    SciTech Connect

    Duff, M; S Crump, S; Robert02 Ray, R; Donna Beals, D

    2007-04-13

    The Federal Bureau of Investigation (FBI) Laboratory currently does not have on site facilities for handling radioactive evidentiary materials and there are no established FBI methods or procedures for decontaminating high explosive (HE) evidence while maintaining evidentiary value. One experimental method for the isolation of HE residue involves using solid phase microextraction or SPME fibers to remove residue of interest. Due to their high affinity for organics, SPME fibers should have little affinity for most metals. However, no studies have measured the affinity of radionuclides for SPME fibers. The focus of this research was to examine the affinity of dissolved radionuclide ({sup 239/240}Pu, {sup 238}U, {sup 237}Np, {sup 85}Sr, {sup 133}Ba, {sup 137}Cs, {sup 60}Co and {sup 226}Ra) and stable radionuclide surrogate metals (Sr, Co, Ir, Re, Ni, Ba, Cs, Nb, Zr, Ru, and Nd) for SPME fibers at the exposure conditions that favor the uptake of HE residues. Our results from radiochemical and mass spectrometric analyses indicate these metals have little measurable affinity for these SPME fibers during conditions that are conducive to HE residue uptake with subsequent analysis by liquid or gas phase chromatography with mass spectrometric detection.

  9. Theoretical phase diagrams for solid H{sub 2}

    SciTech Connect

    Surh, M.P.; Runge, K.J.

    1993-07-01

    Possible phase diagrams for solid molecular para-hydrogen in the 0-200 GPa pressure regime are constructed on the basis of ab initio calculations. Structures for the broken symmetry phase (BSP) and H-A phase have recently been proposed under the assumption that the molecules are centered on sites of a hexagonal close-packed lattice with the ideal c/a ratio, i.e., only molecular orientational and electronic changes are allowed. Symmetry considerations then dictate the simplest phase diagrams consistent with experimental observations, although the possibility of additional transitions cannot be ruled out. A simple model is introduced to describe the BSP and H-A transitions.

  10. SOLID PHASE MICROEXTRACTION SAMPLING OF FIRE DEBRIS RESIDUES IN THE PRESENCE OF RADIONUCLIDE SURROGATE METALS

    SciTech Connect

    Duff, M; Keisha Martin, K; S Crump, S

    2007-03-23

    The Federal Bureau of Investigation (FBI) Laboratory currently does not have on site facilities for handling radioactive evidentiary materials and there are no established FBI methods or procedures for decontaminating highly radioactive fire debris (FD) evidence while maintaining evidentiary value. One experimental method for the isolation of FD residue from radionuclide metals involves using solid phase microextraction (SPME) fibers to remove the residues of interest. Due to their high affinity for organics, SPME fibers should have little affinity for most (radioactive) metals. The focus of this research was to develop an examination protocol that was applicable to safe work in facilities where high radiation doses are shielded from the workers (as in radioactive shielded cells or ''hot cells''). We also examined the affinity of stable radionuclide surrogate metals (Co, Ir, Re, Ni, Ba, Cs, Nb, Zr and Nd) for sorption by the SPME fibers. This was done under exposure conditions that favor the uptake of FD residues under conditions that will provide little contact between the SPME and the FD material (such as charred carpet or wood that contains commonly-used accelerants). Our results from mass spectrometric analyses indicate that SPME fibers show promise for use in the room temperature head space uptake of organic FD residue (namely, diesel fuel oil, kerosene, gasoline and paint thinner) with subsequent analysis by gas chromatography (GC) with mass spectrometric (MS) detection. No inorganic forms of ignitable fluids were included in this study.

  11. All solid-state SBS phase conjugate mirror

    DOEpatents

    Dane, C.B.; Hackel, L.A.

    1999-03-09

    A stimulated Brillouin scattering (SBS) phase conjugate laser mirror uses a solid-state nonlinear gain medium instead of the conventional liquid or high pressure gas medium. The concept has been effectively demonstrated using common optical-grade fused silica. An energy threshold of 2.5 mJ and a slope efficiency of over 90% were achieved, resulting in an overall energy reflectivity of >80% for 15 ns, 1 um laser pulses. The use of solid-state materials is enabled by a multi-pass resonant architecture which suppresses transient fluctuations that would otherwise result in damage to the SBS medium. This all solid state phase conjugator is safer, more reliable, and more easily manufactured than prior art designs. It allows nonlinear wavefront correction to be implemented in industrial and defense laser systems whose operating environments would preclude the introduction of potentially hazardous liquids or high pressure gases. 8 figs.

  12. All solid-state SBS phase conjugate mirror

    DOEpatents

    Dane, Clifford B.; Hackel, Lloyd A.

    1999-01-01

    A stimulated Brillouin scattering (SBS) phase conjugate laser mirror uses a solid-state nonlinear gain medium instead of the conventional liquid or high pressure gas medium. The concept has been effectively demonstrated using common optical-grade fused silica. An energy threshold of 2.5 mJ and a slope efficiency of over 90% were achieved, resulting in an overall energy reflectivity of >80% for 15 ns, 1 um laser pulses. The use of solid-state materials is enabled by a multi-pass resonant architecture which suppresses transient fluctuations that would otherwise result in damage to the SBS medium. This all solid state phase conjugator is safer, more reliable, and more easily manufactured than prior art designs. It allows nonlinear wavefront correction to be implemented in industrial and defense laser systems whose operating environments would preclude the introduction of potentially hazardous liquids or high pressure gases.

  13. Solid–solid phase transitions via melting in metals

    PubMed Central

    Pogatscher, S.; Leutenegger, D.; Schawe, J. E. K.; Uggowitzer, P. J.; Löffler, J. F.

    2016-01-01

    Observing solid–solid phase transitions in-situ with sufficient temporal and spatial resolution is a great challenge, and is often only possible via computer simulations or in model systems. Recently, a study of polymeric colloidal particles, where the particles mimic atoms, revealed an intermediate liquid state in the transition from one solid to another. While not yet observed there, this finding suggests that such phenomena may also occur in metals and alloys. Here we present experimental evidence for a solid–solid transition via the formation of a metastable liquid in a ‘real' atomic system. We observe this transition in a bulk glass-forming metallic system in-situ using fast differential scanning calorimetry. We investigate the corresponding transformation kinetics and discuss the underlying thermodynamics. The mechanism is likely to be a feature of many metallic glasses and metals in general, and may provide further insight into phase transition theory. PMID:27103085

  14. Recent Approaches Toward Solid Phase Synthesis of β-Lactams

    NASA Astrophysics Data System (ADS)

    Mandal, Bablee; Ghosh, Pranab; Basu, Basudeb

    Since the discovery of penicillin in 1929, β-lactam antibiotics have been recognized as potentially chemotherapeutic drugs of incomparable effectiveness, conjugating a broad spectrum of activity with very low toxicity. The primary motif azetidin-2-one ring (β-lactam) has been considered as specific pharmacophores and scaffolds. With the advent of combinatorial chemistry and automated parallel synthesis coupled with ample interests from the pharmaceutical industries, recent trends have been driven mostly by adopting solid phase techniques and polymer-supported synthesis of β-lactams. The present survey will present an overview of the developments on the polymer-supported and solid phase techniques for the preparation of β-lactam ring or β-lactam containing antibiotics published over the last decade. Both unsubstituted and substitutions with different functional groups at various positions of β-lactams have been synthesized using solid phase technology. However, Wang resin and application of Staudinger [2+2] cycloaddition reaction have remained hitherto the major choice. It may be expected that other solid phase approaches involving different resins would be developed in the coming years.

  15. Pyrrole-Imidazole Polyamides: Automated Solid-Phase Synthesis.

    PubMed

    Fang, Lijing; Pan, Zhengyin; Cullis, Paul M; Burley, Glenn A; Su, Wu

    2015-01-01

    In this unit, the fully automated solid-phase synthetic strategy of hairpin Py-Im polyamides is described using triphosgene (BTC) as a coupling agent. This automated methodology is compatible with all the typical building blocks, enabling the facile synthesis of polyamide libraries in 9% to 20% yield in 3 days. PMID:26623976

  16. Kinetics of Microbial Reduction of Solid Phase U(VI)

    SciTech Connect

    Liu, Chongxuan; Jeon, Byong Hun; Zachara, John M.; Wang, Zheming; Dohnalkova, Alice; Fredrickson, Jim K.

    2006-10-01

    Sodium boltwoodite (NaUO2SiO3OH ?1.5H2O) was used to assess the kinetics of microbial reduction of solid phase U(VI) by a dissimilatory metal-reducing bacterium (DMRB), Shewanella oneidensis strain MR-1. The bioreduction kinetics was studied with Na-boltwoodite in suspension or within alginate beads. Concentrations of U(VI)tot and cell number were varied to evaluate the coupling of U(VI) dissolution, diffusion, and microbial activity. Batch experiments were performed in a non-growth medium with lactate as electron donor at pH 6.8 buffered with PIPES. Microscopic and spectroscopic analyses with transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and laser-induced fluorescence spectroscopy (LIFS) collectively indicated that solid phase U(VI) was first dissolved and diffused out of grain interiors before it was reduced on bacterial surfaces and/or within the periplasm. The kinetics of solid phase U(VI) bioreduction was well described by a coupled model of bicarbonate-promoted dissolution of Na-boltwoodite, intraparticle uranyl diffusion, and Monod type bioreduction kinetics with respect to dissolved U(VI) concentration. The results demonstrated the intimate coupling of biological, chemical, and physical processes in microbial reduction of solid phase U(VI).

  17. Affinity of titanium dioxide nanoparticles for sodium montmorillonite clay: Implications for disposal in municipal solid waste landfills

    NASA Astrophysics Data System (ADS)

    Harns, Carrie

    Manufactured nanomaterials are used in a diverse array of commercially available products. Like other consumer goods, a portion of manufactured nano-products will enter municipal solid waste (MSW) landfills. Currently there is little information on the behavior and fate of engineered nanomaterials in MSW landfills and thus we do not know if current landfill designs are suitable for engineered nanomaterials. Of great consequence is understanding how nanomaterials will interact with clays, as they are integral components of composite liner systems. The overall objectives were to determine the affinity of titanium dioxide (TiO2) nanomaterials for montmorillonite as a function of solution chemistry and evaluate the mobility of TiO2 nanomaterials across clay barriers. It was observed that under favorable electrostatic conditions, TiO2 will heteroaggregate with montmorillonite, and TiO2-montmorillonite suspensions will remain stable under unfavorable electrostatic conditions. Additionally, it was observed that under simplified landfill leachate conditions, the clay barrier retained TiO2.

  18. Stress-driven phase transformation and the roughening of solid-solid interfaces.

    PubMed

    Angheluta, L; Jettestuen, E; Mathiesen, J; Renard, F; Jamtveit, B

    2008-03-01

    The application of stress to multiphase solid-liquid systems often results in morphological instabilities. Here we propose a solid-solid phase transformation model for roughening instability in the interface between two porous materials with different porosities under normal compression stresses. This instability is triggered by a finite jump in the free energy density across the interface, and it leads to the formation of fingerlike structures aligned with the principal direction of compaction. The model is proposed as an explanation for the roughening of stylolites-irregular interfaces associated with the compaction of sedimentary rocks that fluctuate about a plane perpendicular to the principal direction of compaction.

  19. Neutron Scattering Studies of Pre-Transitional Effects in Solid-Solid Phase Transformations

    SciTech Connect

    Shapiro, S. M.

    1999-06-30

    Neutron scattering studies have played a fundamental role in understanding solid-solid phase transformations, particularly in studying the lattice dynamical behavior associated with precursor effects. A review of the studies performed on solids exhibiting Martensitic transformations is given below. The mode softening and associated elastic diffuse scattering, previously observed in NiAl alloys, will be discussed as well as more recent work on Ni{sub 2}MnGa, a system exhibiting magnetic order as well as a Martensitic transformation. Also, new results on the precursor effects in ordered and disordered FePt alloys will be presented.

  20. Distribution of Dechlorinating Bacteria between the Aqueous and Solid Phases

    NASA Astrophysics Data System (ADS)

    Cápiro, N. L.; Hatt, J. K.; Wang, Y.; Loeffler, F. E.; Pennell, K. D.

    2010-12-01

    Microbial monitoring of aquifers relies on nucleic acid biomarker analysis, which is typically performed with biomass recovered from groundwater samples; however, it is unclear what fraction of the target population(s) is associated with groundwater (i.e., planktonic cells) or is attached to solid phases (i.e., biofilms). Understanding how the titer of target organism(s) in groundwater correlates with the true cell titers of the target organism in the aquifer (i.e., planktonic plus attached cells) is critical for a meaningful interpretation of the data, the prediction of bioremediation performance, and the implementation of site management strategies. To evaluate the distribution of active cells between resident solid phase and the aqueous phase, one-dimensional columns were packed under water-saturated conditions with Bio-Dechlor INOCULUM, a PCE-to ethene-dechlorinating bacterial consortium containing both multiple Dehalococcoides (Dhc) strains and Geobacter lovleyi strain SZ (GeoSZ). The columns were packed with two distinct solid matrices: a low organic content sandy Federal Fine Ottawa soil or Appling soil with higher organic matter content. Influent reduced mineral salts medium supplied at a groundwater pore-water velocity of 0.3 m/day contained both 10 mM lactate as electron donor and 0.33 mM PCE as electron acceptor. Routine collection of biomass from column side ports and effluent samples measured the titers of target cells in the aqueous phase and determined when steady state conditions had been reached. A second set of column experiments evaluated delivery and filtration effects by the solid matrix (i.e., Federal Fine Ottawa sand versus Appling soil) under the same conditions except that electron donor or acceptor were omitted (no growth conditions). Quantitative real-time PCR (qPCR) analysis using Dhc and GeoSZ 16S rRNA gene-targeted primer and probe sets determined the planktonic cell counts, and destructive sampling of the columns allowed measurement

  1. The solid phase of ginkgolide K: Structure and physicochemical properties

    NASA Astrophysics Data System (ADS)

    Zhang, Yiwen; Zhang, Guoshun; Wang, Zhenzhong; Lv, Yang; Xiao, Wei

    2016-05-01

    Four solvates of ginkgolide K with dimethyl sulfoxide(I), water molecule(II), acetone-isopropyl alcohol(III), methanol-ethanol(IV) and one solvate-free (V) have been described in this work. And the solid-state techniques such as X-ray diffraction, thermal analysis and Fourier transform infrared spectroscopy were used for characterization of the solid phases. The single crystal structures of ginkgolide K solvates (I-IV) have been determined. Ginkgolide K shows strong inflexibility and solvents being incorporated in the crystal structure results in it forming polymorphs via the diverse hydrogen bond interactions.

  2. Phase field simulation of a droplet impacting a solid surface

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Qian, Tie-Zheng; Wang, Xiao-Ping

    2016-02-01

    We simulate a droplet impacting on a solid surface using a phase field model consisting of the Cahn-Hilliard and Navier Stokes equations with the generalized Navier boundary condition. An efficient gradient stable scheme is used to solve the system in axisymmetric coordinates. Our objective is to understand numerically the mechanisms leading to different impacting phenomena such as adherence, bouncing, partial bouncing, and splashing. In particular, we study how various processes are affected by the relevant dimensionless parameters: the Reynolds number, Weber number, density ratio, viscosity ratio, and the wettability of the solid surface. We also compare our numerical results with the experimental results and observe almost quantitative agreement.

  3. Formation of target-specific binding sites in enzymes: solid-phase molecular imprinting of HRP

    NASA Astrophysics Data System (ADS)

    Czulak, J.; Guerreiro, A.; Metran, K.; Canfarotta, F.; Goddard, A.; Cowan, R. H.; Trochimczuk, A. W.; Piletsky, S.

    2016-05-01

    Here we introduce a new concept for synthesising molecularly imprinted nanoparticles by using proteins as macro-functional monomers. For a proof-of-concept, a model enzyme (HRP) was cross-linked using glutaraldehyde in the presence of glass beads (solid-phase) bearing immobilized templates such as vancomycin and ampicillin. The cross-linking process links together proteins and protein chains, which in the presence of templates leads to the formation of permanent target-specific recognition sites without adverse effects on the enzymatic activity. Unlike complex protein engineering approaches commonly employed to generate affinity proteins, the method proposed can be used to produce protein-based ligands in a short time period using native protein molecules. These affinity materials are potentially useful tools especially for assays since they combine the catalytic properties of enzymes (for signaling) and molecular recognition properties of antibodies. We demonstrate this concept in an ELISA-format assay where HRP imprinted with vancomycin and ampicillin replaced traditional enzyme-antibody conjugates for selective detection of templates at micromolar concentrations. This approach can potentially provide a fast alternative to raising antibodies for targets that do not require high assay sensitivities; it can also find uses as a biochemical research tool, as a possible replacement for immunoperoxidase-conjugates.Here we introduce a new concept for synthesising molecularly imprinted nanoparticles by using proteins as macro-functional monomers. For a proof-of-concept, a model enzyme (HRP) was cross-linked using glutaraldehyde in the presence of glass beads (solid-phase) bearing immobilized templates such as vancomycin and ampicillin. The cross-linking process links together proteins and protein chains, which in the presence of templates leads to the formation of permanent target-specific recognition sites without adverse effects on the enzymatic activity. Unlike

  4. Phenomena of solid state grain boundaries phase transition in technology

    SciTech Connect

    Minaev, Y. A.

    2015-03-30

    The results of study the phenomenon, discovered by author (1971), of the phase transition of grain boundary by the formation of two-dimensional liquid or quasi-liquid films have been done. The described phenomena of the first order phase transition (two-dimensional melting) at temperatures 0.6 – 0.9 T{sub S0} (of the solid state melting point) is a fundamental property of solid crystalline materials, which has allowed to revise radically scientific representations about a solid state of substance. Using the mathematical tools of the film thermodynamics it has been obtained the generalized equation of Clausius - Clapeyron type for two-dimensional phase transition. The generalized equation has been used for calculating grain boundary phase transition temperature T{sub Sf} of any metal, which value lies in the range of (0.55…0.86) T{sub S0}. Based on these works conclusions the develop strategies for effective forming of coatings (by thermo-chemical processing) on surface layers of functional alloys and hard metals have been made. The short overview of the results of some graded alloys characterization has been done.

  5. Fundamental and practical studies on high-performance liquid affinity chromatography of biopolymers with novel stationary phases

    SciTech Connect

    Bacolod, M.D.

    1992-01-01

    Rigid microparticulate stationary phases having surface-bound metal chelating functions were developed and evaluated in high performance metal chelate affinity chromatography of proteins. Silica- and polystyrene-divinylbenzene-based metal chelate sorbents were produced in wide pore and in non-porous type of column packings. A major effort has been placed on development of non-porous highly crosslinked polystyrene-divinylbenzene (PSDVB). These PSDVB microparticles were produced by a two-step swelling polymerization, and exhibited excellent mechanical strength over a wide range of flow-rates and composition used in high performance liquid chromatography (HPLC). Simple and reproducible hydrophilic coatings were developed for the surface modification of hydrophobic PSDVB supports. A tetradentate metal chelating ligand, ethylenediamine-N, N[prime]-diacetic acid (EDDA), was covalently bound to the surface of the various supports. Sorbents having iminodiacetic acid (IDA) metal chelating functions were also evaluated. The hydrophilic character and surface coverage of various stationary phases were assessed chromatographically. Studies concerning the effects of eluent pH as well as the nature and concentration of salts on retention and selectivity with different metal chelate stationary phases having various immobilized metal ions were carried out. Elution schemes were developed for rapid separation of proteins in metal chelate affinity chromatography. EDDA stationary phases in metal forms can be viewed as complementary to IDA stationary phases since they afforded different selectivity and retentivity toward proteins. Hydrophilic PSDVB could be functionalized with IDA or EDDA metal chelating ligands or lectins. The non-porous metal chelate stationary phases afforded rapid separation of proteins by the development of multiple gradient systems, which permitted higher column peak capacity, enabling the separation of a greater number of proteins in a single chromatographic run.

  6. Synthesis of chitosan molecularly imprinted polymers for solid-phase extraction of methandrostenolone.

    PubMed

    Wang, Yun; Wang, Enlan; Wu, Ziming; Li, Huan; Zhu, Zhi; Zhu, Xinsheng; Dong, Ying

    2014-01-30

    Chitosan molecularly imprinted polymers (CHI-MIPs) for selective extraction of methandrostenolone (MA) was synthesized by cross-linking of chitosan with epichlorohydrin in the presence of MA as the template molecule. Systematic investigations of the influences of template, functional polymer, cross-linker as well as porogen concentrations on the rebinding capacity of CHI-MIPs were carried out. Adsorption and kinetic binding experiments indicated that the synthesized CHI-MIPs had high adsorption and excellent affinity to MA. Solid-phase extraction (SPE) using the prepared CHI-MIPs as adsorbent was then investigated, and the optimum loading and eluting conditions for SPE of the MA were established. The optimized SPE procedure was used to extract the MA from several spiked samples and a good sample clean-up was obtained with the average recoveries ranged from 95.97 to 101.79%. PMID:24299807

  7. Synthesis and application of cephalexin imprinted polymer for solid phase extraction in milk.

    PubMed

    Lata, Kiran; Sharma, Rajan; Naik, Laxmana; Rajput, Y S; Mann, Bimlesh

    2015-10-01

    Molecular imprinted polymer (MIP) against cephalexin was synthesized by co-polymerization of functional monomer, cross-linker, radical initiator, along with target molecule (cephalexin) in a porogenic material. Binding of cephalexin towards prepared MIP was studied in different solvents (water, methanol, 1M NaCl, acetone and acetonitrile) and best binding was observed in methanol. Partition coefficient and selectivity of prepared imprint and non-imprint was also studied. Cross reactivity in terms of binding efficiency was also assessed with other antibiotics. Chromatographic study of MIP was carried out by packing prepared imprint into glass column. MIP was used as matrix in solid phase extraction (SPE) for recovery of cephalexin from spiked milk samples for further estimation by high performance liquid chromatography. No interference was observed from milk components after elution of cephalexin from MIP, indicating selectivity and affinity of MIP. On the other hand, interference was observed in eluate obtained from C18 SPE column. PMID:25872441

  8. Direct potentiometric quantification of histamine using solid-phase imprinted nanoparticles as recognition elements.

    PubMed

    Basozabal, Itsaso; Guerreiro, Antonio; Gomez-Caballero, Alberto; Aranzazu Goicolea, M; Barrio, Ramón J

    2014-08-15

    A new potentiometric sensor based on molecularly imprinted nanoparticles produced via the solid-phase imprinting method was developed. For histamine quantification, the nanoparticles were incorporated within a membrane, which was then used to fabricate an ion-selective electrode. The use of nanoparticles with high affinity and specificity allowed for label-free detection/quantification of histamine in real samples with short response times. The sensor could selectively quantify histamine in presence of other biogenic amines in real wine and fish matrices. The limit of detection achieved was 1.12×10(-6)molL(-1), with a linear range between 10(-6) and 10(-2)molL(-1) and a response time below 20s, making the sensor as developed a promising tool for direct quantification of histamine in the food industry.

  9. Studies in Solid Phase Peptide Synthesis: A Personal Perspective

    SciTech Connect

    Mitchell, A R

    2007-06-01

    By the early 1970s it had became apparent that the solid phase synthesis of ribonuclease A could not be generalized. Consequently, virtually every aspect of solid phase peptide synthesis (SPPS) was reexamined and improved during the decade of the 1970s. The sensitive detection and elimination of possible side reactions (amino acid insertion, N{sup {alpha}}-trifluoroacetylation, N{sup {alpha}{var_epsilon}}-alkylation) was examined. The quantitation of coupling efficiency in SPPS as a function of chain length was studied. A new and improved support for SPPS, the 'PAM-resin', was prepared and evaluated. These and many other studies from the Merrifield laboratory and elsewhere increased the general acceptance of SPPS leading to the 1984 Nobel Prize in Chemistry for Bruce Merrifield.

  10. Kinetics of Solid Phase Reactions at High Pressure and Temperature

    SciTech Connect

    Zaug, J M; Farber, D L; Saw, C K; Weeks, B L

    2002-02-11

    We report on the subject of temperature and/or pressure induced solid-solid phase transitions of energetic molecular crystals. Over the last three years we have applied experimental techniques that when used simultaneously provide insight into some of the complexities that govern reaction rate processes. After more than 55 years of study a global kinetics model describing the P-T phase space transition kinetics of such materials as HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) is not only missing, but from a formal perspective is perhaps as many years away from completion. The essence of this report describes what material parameters affect first-order reaction rates of the CHNO moiety of molecular crystals and introduces the application of new experimental tools thus permitting quantifiable studies of important rate limiting mechanisms.

  11. Solid-Phase Biological Assays for Drug Discovery

    NASA Astrophysics Data System (ADS)

    Forsberg, Erica M.; Sicard, Clémence; Brennan, John D.

    2014-06-01

    In the past 30 years, there has been a significant growth in the use of solid-phase assays in the area of drug discovery, with a range of new assays being used for both soluble and membrane-bound targets. In this review, we provide some basic background to typical drug targets and immobilization protocols used in solid-phase biological assays (SPBAs) for drug discovery, with emphasis on particularly labile biomolecular targets such as kinases and membrane-bound receptors, and highlight some of the more recent approaches for producing protein microarrays, bioaffinity columns, and other devices that are central to small molecule screening by SPBA. We then discuss key applications of such assays to identify drug leads, with an emphasis on the screening of mixtures. We conclude by highlighting specific advantages and potential disadvantages of SPBAs, particularly as they relate to particular assay formats.

  12. Oscillatory burning of solid propellants including gas phase time lag.

    NASA Technical Reports Server (NTRS)

    T'Ien, J. S.

    1972-01-01

    An analysis has been performed for oscillatory burning of solid propellants including gas phase time lag. The gaseous flame is assumed to be premixed and laminar with a one-step overall chemical reaction. The propellant is assumed to decompose according to the Arrenhius Law, with no condensed phase reaction. With this model, strong gas phase resonance has been found in certain cases at the characteristic gas-phase frequencies, but the peaking of the acoustic admittance is in the direction favoring the damping of pressure waves. At still higher frequencies, moderate wave-amplifying ability was found. The limit of low frequency response obtained previously by Denison and Baum was recovered, and the limitations of the quasi-steady theory were investigated.

  13. New Phase Transition of Solid Bromine under High Pressure

    SciTech Connect

    San-Miguel, A.; Libotte, H.; Gaspard, J.-P.; Gauthier, M.; Aquilanti, G.; Pascarelli, S.

    2007-07-06

    Solid bromine has been studied by x-ray absorption spectroscopy experiments up to a maximum pressure of 75 GPa. The data analysis of the extended fine structure reveals that the intramolecular distance first increases, reaching its maximum value at 25{+-}5 GPa. From this value the intramolecular distance abruptly begins to decrease evidencing a nonpreviously observed phase transformation taking place at 25{+-}5 GPa. A maximum variation of 0.08 A ring is observed at 65{+-}5 GPa where again a phase transition occurs. This last transformation could correspond with the recently observed change to an incommensurate modulated phase. We discuss the possible generalization of the observed new phase transition at 25{+-}5 GPa to the case of the other halogens.

  14. Solid-phase chemistry driven by energetic processing

    NASA Astrophysics Data System (ADS)

    Palumbo, M. E.

    2015-01-01

    Molecules in the solid phase have been detected in the line of sight of quiescent molecular clouds and star forming regions as icy mantles on dust grains. Although about 10 molecular species have been firmly identified in icy grain mantles, it is believed that many, also complex, species are present in the solid phase which are not detected due to the detection limits of infrared spectroscopy. It is generally accepted that some of the observed species (such as CO) freeze out from the gas phase while others (such as water and methanol) are formed on grains after surface reactions. Other species (such as CO2 and OCS), are not expected to freeze out in significant amount from the gas phase and grain surface models do not account for their observed abundance. It has been suggested that these molecules, along with other more complex species, are formed after energetic processing (i.e. cosmic ion and UV irradiation) of icy grain mantles. All these species are released to the gas-phase after desorption of icy mantles. Here we will present some recent laboratory experiments which show the formation of (complex) molecular species after energetic processing of simple ices. Icy targets have been processed by ion bombardment and UV photolysis both in separate experiments and recently, for the first time, simultaneously. When C-rich species are present in the initial ice, an organic refractory material is also formed.

  15. Clinically relevant interpretation of solid phase assays for HLA antibody

    PubMed Central

    Bettinotti, Maria P.; Zachary, Andrea A.; Leffell, Mary S.

    2016-01-01

    Purpose of review Accurate and timely detection and characterization of human leukocyte antigen (HLA) antibodies are critical for pre-transplant and post-transplant immunological risk assessment. Solid phase immunoassays have provided increased sensitivity and specificity, but test interpretation is not always straightforward. This review will discuss the result interpretation considering technical limitations; assessment of relative antibody strength; and the integration of data for risk stratification from complementary testing and the patient's immunological history. Recent findings Laboratory and clinical studies have provided insight into causes of test failures – false positive reactions because of antibodies to denatured HLA antigens and false negative reactions resulting from test interference and/or loss of native epitopes. Test modifications permit detection of complement-binding antibodies and determination of the IgG subclasses. The high degree of specificity of single antigen solid phase immunoassays has revealed the complexity and clinical relevance of antibodies to HLA-C, HLA-DQ, and HLA-DP antigens. Determination of antibody specificity for HLA epitopes enables identification of incompatible antigens not included in test kits. Summary Detection and characterization of HLA antibodies with solid phase immunoassays has led to increased understanding of the role of those antibodies in graft rejection, improved treatment of antibody-mediated rejection, and increased opportunities for transplantation. However, realization of these benefits requires careful and accurate interpretation of test results. PMID:27200498

  16. Immobilization and functional reconstitution of antibody Fab fragment by solid-phase refolding.

    PubMed

    Kumada, Yoichi; Hamasaki, Kyoto; Nakagawa, Aya; Sasaki, Eiju; Shirai, Tatsunori; Okumura, Masahiro; Inoue, Manami; Kishimoto, Michimasa

    2013-12-31

    In this study, we demonstrated the successful preparation of a Fab antibody-immobilized hydrophilic polystyrene (phi-PS) plate via one- and two-step solid-phase refolding methods. Both polystyrene-binding peptide (PS-tag)-fused Fd fragment of heavy chain (Fab H-PS) and full-length of light-chain (Fab L-PS) were individually produced in insoluble fractions of Escherichia coli cells, and they were highly purified in the presence of 8M of urea. Antigen-binding activities of Fab antibody immobilized were correctly recovered by the one-step solid-phase refolding method that a mixture of Fab H-PS and Fab L-PS was immobilized in the presence of 0.5-2M urea, followed by surface washing of the phi-PS plate with PBST. These results indicate that by genetic fusion of a PS-tag, a complex between Fab H and Fab L was efficiently immobilized on the surface of a phi-PS plate even in the presence of a low concentration of urea, and was then correctly refolded to retain its high antigen-binding activity via removal of the urea. A two-step solid-phase refolding method whereby Fab H-PS and Fab L-PS were successively refolded on the surface of a phi-PS plate also resulted in Fab antibody formation on the plate. Furthermore, both the binding affinity and the specificity of the Fab antibody produced by the two-step method were highly maintained, according to the results of sandwich ELISA and competitive ELISA using Fab antibody-immobilized plate via two-step solid-phase refolding. Thus, the solid-phase refolding method demonstrated in this study should be quite useful for the preparation of a Fab antibody-immobilized PS surface with high efficiency from individually produced Fab H-PS and Fab L-PS. This method will be applicable to the preparation of a large Fab antibody library on the surface of a PS plate for use in antibody screening.

  17. Phase field modeling and simulation of three-phase flow on solid surfaces

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Wang, Xiao-Ping

    2016-08-01

    Phase field models are widely used to describe the two-phase system. The evolution of the phase field variables is usually driven by the gradient flow of a total free energy functional. The generalization of the approach to an N phase (N ≥ 3) system requires some extra consistency conditions on the free energy functional in order for the model to give physically relevant results. A projection approach is proposed for the derivation of a consistent free energy functional for the three-phase Cahn-Hilliard equations. The system is then coupled with the Navier-Stokes equations to describe the three-phase flow on solid surfaces with moving contact line. An energy stable scheme is developed for the three-phase flow system. The discrete energy law of the numerical scheme is proved which ensures the stability of the scheme. We also show some numerical results for the dynamics of triple junctions and four phase contact lines.

  18. Selective removal of phosphorus from wastewater combined with its recovery as a solid-phase fertilizer.

    PubMed

    Sengupta, Sukalyan; Pandit, Arka

    2011-05-01

    Influx of Phosphorus (P) into freshwater ecosystems is the primary cause of eutrophication which has many undesirable effects. Therefore, P discharge limits for effluents from WWTPs is becoming increasingly common, and may be as low as 10 μg/L as P. While precipitation, filtration, membrane processes, Enhanced Biological Phosphorus Removal (EBPR) and Physico-chemical (adsorption based) methods have been successfully used to effect P removal, only adsorption has the potential to recover the P as a usable fertilizer. This benefit will gain importance with time since P is a non-renewable resource and is mined from P-rich rocks. This article provides details of a process where a polymeric anion exchanger is impregnated with iron oxide nanoparticles to effectuate selective P removal from wastewater and its recovery as a solid-phase fertilizer. Three such hybrid materials were studied: HAIX, DOW-HFO, & DOW-HFO-Cu. Each of these materials combines the durability, robustness, and ease-of-use of a polymeric ion-exchanger resin with the high sorption affinity of Hydrated Ferric Oxide (HFO) toward phosphate. Laboratory experiments demonstrate that each of the three materials studies can selectively remove phosphate from the background of competing anions and phosphorus can be recovered as a solid-phase fertilizer upon efficient regeneration of the exchanger and addition of a calcium or magnesium salt in equimolar (Ca/P or Mg/P) ratio. Also, there is no leaching of Fe or Cu from any of these hybrid exchangers.

  19. Development of andrographolide molecularly imprinted polymer for solid-phase extraction

    NASA Astrophysics Data System (ADS)

    Yin, Xiaoying; Liu, Qingshan; Jiang, Yifan; Luo, Yongming

    2011-06-01

    A method employing molecularly imprinted polymer (MIP) as selective sorbent for solid-phase extraction (SPE) to pretreat samples was developed. The polymers were prepared by precipitation polymerization with andrographolide as template molecule. The structure of MIP was characterized and its static adsorption capacity was measured by the Scatchard equation. In comparison with C 18-SPE and non-imprinted polymer (NIP) SPE column, MIP-SPE column displays high selectivity and good affinity for andrographolide and dehydroandrographolide for extract of herb Andrographis paniculata ( Burm.f.) Nees (APN). MIP-SPE column capacity was 11.9 ± 0.6 μmol/g and 12.1 ± 0.5 μmol/g for andrographolide and dehydroandrographolide, respectively and was 2-3 times higher than that of other two columns. The precision and accuracy of the method developed were satisfactory with recoveries between 96.4% and 103.8% (RSD 3.1-4.3%, n = 5) and 96.0% and 104.2% (RSD 2.9-3.7%, n = 5) for andrographolide and dehydroandrographolide, respectively. Various real samples were employed to confirm the feasibility of method. This developed method demonstrates the potential of molecularly imprinted solid phase extraction for rapid, selective, and effective sample pretreatment.

  20. Formation of target-specific binding sites in enzymes: solid-phase molecular imprinting of HRP.

    PubMed

    Czulak, J; Guerreiro, A; Metran, K; Canfarotta, F; Goddard, A; Cowan, R H; Trochimczuk, A W; Piletsky, S

    2016-06-01

    Here we introduce a new concept for synthesising molecularly imprinted nanoparticles by using proteins as macro-functional monomers. For a proof-of-concept, a model enzyme (HRP) was cross-linked using glutaraldehyde in the presence of glass beads (solid-phase) bearing immobilized templates such as vancomycin and ampicillin. The cross-linking process links together proteins and protein chains, which in the presence of templates leads to the formation of permanent target-specific recognition sites without adverse effects on the enzymatic activity. Unlike complex protein engineering approaches commonly employed to generate affinity proteins, the method proposed can be used to produce protein-based ligands in a short time period using native protein molecules. These affinity materials are potentially useful tools especially for assays since they combine the catalytic properties of enzymes (for signaling) and molecular recognition properties of antibodies. We demonstrate this concept in an ELISA-format assay where HRP imprinted with vancomycin and ampicillin replaced traditional enzyme-antibody conjugates for selective detection of templates at micromolar concentrations. This approach can potentially provide a fast alternative to raising antibodies for targets that do not require high assay sensitivities; it can also find uses as a biochemical research tool, as a possible replacement for immunoperoxidase-conjugates. PMID:27174700

  1. Leaching behavior and solubility -- Controlling solid phases of heavy metals in municipal solid waste incinerator ash

    SciTech Connect

    Johnson, C.A.; Ziegler, F.; Kersten, M.; Moor, H.C.

    1996-12-31

    This paper highlights the uses and limitations of thermodynamic calculations in the planning of leach tests in the laboratory or for research in the field. Heavy metal solubility has been studied in leachate from Landfill Lostorf, AG, Switzerland. Also, the influence of pH on the solubility of Cu, Pb, Cd and Zn has been determined in the laboratory. The results have been compared with the maximum allowable heavy metal concentrations in equilibrium with the appropriate (hydr)oxides and carbonates. Copper is supersaturated with respect to Cu(OH){sub 2} in both laboratory and field studies. Complexation with organic ligands is a probable explanation for this observation. Both Zn and Pb are undersaturated with respect to pure (hydr)oxides and carbonates, though agreement between calculations and measurements are close enough, that PbCO{sub 3} could be controlling the solubility in the laboratory experiments. The markedly lower concentrations of Pb in the field in comparison with the laboratory data could be explained by the affinity for Pb to bind to solids and the higher solid:solution ratio in field conditions. The solubility of Cd could be controlled by the formation of CdCO{sub 3}. The relatively high concentrations of Mo in the landfill leachate could be limited by the precipitation of CaMoO{sub 4}.

  2. Mechanism of phase transition, from vapor to solid: Transient liquid phase is between the two

    NASA Astrophysics Data System (ADS)

    Mahapatra, A. K.; Wang, Junyong; Zhang, Hongwei; Han, Min

    2016-08-01

    The mechanism of phase transition, from vapor to solid, is studied by producing non-stoichiometric ZnO and CdS nanoclusters (NCs) by low-energy cluster beam deposition technique, and examining their morphological and compositional evolution over a long span of time. It is concluded that the transition of vapor to solid goes through a transient liquid phase: coagulation of a large number of atomic clusters first forms liquid NCs which then solidify. The nature of the material and the experimental conditions determine crystallinity and shape of the NCs during the solidification process.

  3. Engineering aspects of solid-state phase conjugate lasers

    NASA Astrophysics Data System (ADS)

    Gregor, Eduard; Mordaunt, David W.; Matthews, Steven C.; Kahan, Osher; Muir, Alexander R.; Palombo, Mario

    1992-06-01

    An engineering approach for the development of laser hardware that takes advantage of the special properties of phase conjugation is reported. The principal advantages of conjugate solid-state lasers are alignment stability and passive compensation of thermal distortion in a double pass laser amplifier chain. Attention is given to the application of phase conjugation techniques to the design, fabrication, and field testing of an Nd:YAG second harmonic 0.5 Joule, 30 Hertz flashlamp pumped laser in a master oscillator power amplifier configuration. The double pass amplifier featured a phase conjugate mirror and a second harmonic crystal within the amplifier chain. The basic Nd:YAG laser produced a doubling efficiency of 75 percent from 1064 to 532 nm. This output was subsequently used as the source, and a conversion efficiency of 80 percent into six wavelengths in the visible spectrum was obtained using stimulated rotational Raman scattering.

  4. The Influence of the Linker Geometry in Bis(3-hydroxy-N-methyl-pyridin-2-one) Ligands on Solution-Phase Uranyl Affinity

    SciTech Connect

    Szigethy, Geza; Raymond, Kenneth

    2010-08-12

    Seven water-soluble, tetradentate bis(3-hydroxy-N-methyl-pyridin-2-one) (bis-Me-3,2-HOPO) ligands were synthesized that vary only in linker geometry and rigidity. Solution phase thermodynamic measurements were conducted between pH 1.6 and pH 9.0 to determine the effects of these variations on proton and uranyl cation affinity. Proton affinity decreases by introduction of the solubilizing triethylene glycol group as compared to un-substituted reference ligands. Uranyl affinity was found to follow no discernable trends with incremental geometric modification. The butyl-linked 4Li-Me-3,2-HOPO ligand exhibited the highest uranyl affinity, consistent with prior in vivo decorporation results. Of the rigidly-linked ligands, the o-phenylene linker imparted the best uranyl affinity to the bis-Me-3,2-HOPO ligand platform.

  5. Immunomagnetic separation and solid-phase detection of Bordetella pertussis.

    PubMed Central

    Stark, M; Reizenstein, E; Uhlén, M; Lundeberg, J

    1996-01-01

    In the present study, novel solid-phase methods were used for both sample preparation and PCR detection of Bordetella pertussis. The sample preparation was performed by immunomagnetic separation with paramagnetic beads coated with polyclonal antibodies directed toward the surface antigens of the bacteria. The precoated immunobeads were directly used on nasopharyngeal aspirates to capture the bacteria on the solid support and were subsequently transferred to the PCR tube with no further manipulations. The region encompassing the pertussis toxin promoter was analyzed to allow direct discrimination between the three major Bordetella species (B. pertussis, B. parapertussis, and B. bronchiseptica). The resulting amplicons were captured on a second magnetic solid phase, allowing detection and restriction analysis of the target sequence. A colorimetric detection system based on a DNA binding fusion protein enabled the use of standardized enzyme-linked immunosorbent format tests both for the detection of Bordetella spp. and for species evaluation. When the optimized system was evaluated on 55 clinical aspirate samples, 21 of 22 (95%) culture-positive samples were positive by the system that we developed. In addition, two samples were positive by the PCR-based assay, while the culture assay was negative. The implications of these results are discussed. PMID:8815083

  6. Solid State NMR Studies of the Aluminum Hydride Phases

    NASA Technical Reports Server (NTRS)

    Hwang, Son-Jong; Bowman, R. C., Jr.; Graetz, Jason; Reilly, J. J.

    2006-01-01

    Several solid state NMR techniques including magic-angle-spinning (MAS) and multiple-quantum (MQ) MAS experiments have been used to characterize various AlH3 samples. MAS-NMR spectra for the 1H and 27Al nuclei have been obtained on a variety of AlH3 samples that include the (beta)- and (gamma)- phases as well as the most stable (alpha)-phase. While the dominant components in these NMR spectra correspond to the aluminum hydride phases, other species were found that include Al metal, molecular hydrogen (H2), as well as peaks that can be assigned to Al-O species in different configurations. The occurrence and concentration of these extraneous components are dependent upon the initial AlH3 phase composition and preparation procedures. Both the (beta)-AlH3 and (gamma)-AlH3 phases were found to generate substantial amounts of Al metal when the materials were stored at room temperature while the (alpha)-phase materials do not exhibit these changes.

  7. 40 CFR 227.32 - Liquid, suspended particulate, and solid phases of a material.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... solid phases of a material. 227.32 Section 227.32 Protection of Environment ENVIRONMENTAL PROTECTION... MATERIALS Definitions § 227.32 Liquid, suspended particulate, and solid phases of a material. (a) For the... obtained above prior to centrifugation and filtration. The solid phase includes all material settling...

  8. Heterogeneous Phase Transfer Catalysis in Solid Phase Syntheses of Anth-Cyclic Tetrapeptides.

    PubMed

    Xin, Dongyue; Yuan, Jian; Wong, Kwok-Yin; Burgess, Kevin

    2016-09-01

    This study features solid phase syntheses of cyclic tetrapeptides containing anthranilic acid (Anth) on relatively inexpensive resins derived from polystyrene. It proved to be difficult to hydrolyze a supported Anth-methyl ester unless a phase transfer catalyst was added to facilitate transport of hydroxide into the swollen hydrophobic gel state of the resin. We suggest this may be an under-appreciated strategy for improving syntheses on polystyrene supports. PMID:27552148

  9. Solid Phase Synthesis of Helically Folded Aromatic Oligoamides.

    PubMed

    Dawson, S J; Hu, X; Claerhout, S; Huc, I

    2016-01-01

    Aromatic amide foldamers constitute a growing class of oligomers that adopt remarkably stable folded conformations. The folded structures possess largely predictable shapes and open the way toward the design of synthetic mimics of proteins. Important examples of aromatic amide foldamers include oligomers of 7- or 8-amino-2-quinoline carboxylic acid that have been shown to exist predominantly as well-defined helices, including when they are combined with α-amino acids to which they may impose their folding behavior. To rapidly iterate their synthesis, solid phase synthesis (SPS) protocols have been developed and optimized for overcoming synthetic difficulties inherent to these backbones such as low nucleophilicity of amine groups on electron poor aromatic rings and a strong propensity of even short sequences to fold on the solid phase during synthesis. For example, acid chloride activation and the use of microwaves are required to bring coupling at aromatic amines to completion. Here, we report detailed SPS protocols for the rapid production of: (1) oligomers of 8-amino-2-quinolinecarboxylic acid; (2) oligomers containing 7-amino-8-fluoro-2-quinolinecarboxylic acid; and (3) heteromeric oligomers of 8-amino-2-quinolinecarboxylic acid and α-amino acids. SPS brings the advantage to quickly produce sequences having varied main chain or side chain components without having to purify multiple intermediates as in solution phase synthesis. With these protocols, an octamer could easily be synthesized and purified within one to two weeks from Fmoc protected amino acid monomer precursors. PMID:27586338

  10. Experimental determination of the gas phase proton affinities of the conjugate base anions of 2-iodoxybenzoic acid (IBX) and 2-iodosobenzoic acid (IBA).

    PubMed

    Waters, Tom; Boulton, Jack; Clark, Timothy; Gallen, Michael J; Williams, Craig M; O'Hair, Richard A J

    2008-07-21

    The gas phase anion proton affinities of the periodinane anions IBX- and IBA- were examined using mass spectrometry-based experiments, and estimated as 1300 +/- 25 and 1390 +/- 10 kJ mol(-1), respectively. The experimental results were supported by theoretical calculations, which yielded proton affinities of 1336 and 1392 kJ mol(-1) for IBX- and IBA- respectively, at the B3LYP/aug-cc-PVDZ level of theory.

  11. Solid phase microextraction fills the gap in tissue sampling protocols.

    PubMed

    Bojko, Barbara; Gorynski, Krzysztof; Gomez-Rios, German Augusto; Knaak, Jan Matthias; Machuca, Tiago; Spetzler, Vinzent Nikolaus; Cudjoe, Erasmus; Hsin, Michael; Cypel, Marcelo; Selzner, Markus; Liu, Mingyao; Keshavjee, Shaf; Pawliszyn, Janusz

    2013-11-25

    Metabolomics and biomarkers discovery are an integral part of bioanalysis. However, untargeted tissue analysis remains as the bottleneck of such studies due to the invasiveness of sample collection, as well as the laborious and time-consuming sample preparation protocols. In the current study, technology integrating in vivo sampling, sample preparation and global extraction of metabolites--solid phase microextraction was presented and evaluated during liver and lung transplantation in pig model. Sampling approaches, including selection of the probe, transportation, storage conditions and analyte coverage were discussed. The applicability of the method for metabolomics studies was demonstrated during lung transplantation experiments. PMID:24216199

  12. Solid-Phase Synthesis of Tetrahydropyridazinedione-Constrained Peptides

    PubMed Central

    2015-01-01

    The design and solid-phase synthesis of tetrahydropyridazine-3,6-dione (Tpd) peptidomimetics derived from backbone-aminated peptides is reported. The described protocol features the synthesis of chiral α-hydrazino acids suitable for chemoselective incorporation into growing peptide chains. Acid-catalyzed cyclization to form the Tpd ring during cleavage affords the target peptidomimetics in good yield and purity. The scope of Tpd incorporation is demonstrated through the synthesis of constrained peptides featuring nucleophilic/electrophilic side chains and sterically encumbered α-substituted hydrazino acid residues. PMID:25295511

  13. Nitrogen containing privileged structures and their solid phase combinatorial synthesis.

    PubMed

    Verma, Amit; Yadav, Mange Ram; Giridhar, Rajani; Prajapati, Navnit; Tripathi, Avinash C; Saraf, Shailendra K

    2013-06-01

    The existence of preferred molecular scaffolds that possess inherent biological activity, called privileged structures, is now well recognized. Such privileged structures not only provide enhanced drug-like properties but also give new hits for developing leads. The synthesis of combinatorial libraries, especially with the insertion of privileged substructures into heterocyclic moieties containing nitrogen, provides for a greater probability of the discovery of novel lead compounds using chemical transformation. The review focuses on the progress in the solid-phase synthetic strategies of nitrogen containing privileged structures over the years.

  14. Advances in solid-phase extraction disks for environmental chemistry

    USGS Publications Warehouse

    Thurman, E.M.; Snavely, K.

    2000-01-01

    The development of solid-phase extraction (SPE) for environmental chemistry has progressed significantly over the last decade to include a number of new sorbents and new approaches to SPE. One SPE approach in particular, the SPE disk, has greatly reduced or eliminated the use of chlorinated solvents for the analysis of trace organic compounds. This article discusses the use and applicability of various SPE disks, including micro-sized disks, prior to gas chromatography-mass spectrometry for the analysis of trace organic compounds in water. Copyright (C) 2000 Elsevier Science B.V.

  15. Liquid and Solid Phases of ^{3}He on Graphite.

    PubMed

    Gordillo, M C; Boronat, J

    2016-04-01

    Recent heat-capacity experiments show quite unambiguously the existence of a liquid ^{3}He phase adsorbed on graphite. This liquid is stable at an extremely low density, possibly one of the lowest found in nature. Previous theoretical calculations of the same system, and in strictly two dimensions, agree with the result that this liquid phase is not stable and the system is in the gas phase. We calculated the phase diagram of normal ^{3}He adsorbed on graphite at T=0 using quantum Monte Carlo methods. Considering a fully corrugated substrate, we observe that at densities lower than 0.006  Å^{-2} the system is a very dilute gas that, at that density, is in equilibrium with a liquid of density 0.014  Å^{-2}. Our prediction matches very well the recent experimental findings on the same system. On the contrary, when a flat substrate is considered, no gas-liquid coexistence is found, in agreement with previous calculations. We also report results on the different solid structures, and on the corresponding phase transitions that appear at higher densities.

  16. Liquid and Solid Phases of 3He on Graphite

    NASA Astrophysics Data System (ADS)

    Gordillo, M. C.; Boronat, J.

    2016-04-01

    Recent heat-capacity experiments show quite unambiguously the existence of a liquid 3He phase adsorbed on graphite. This liquid is stable at an extremely low density, possibly one of the lowest found in nature. Previous theoretical calculations of the same system, and in strictly two dimensions, agree with the result that this liquid phase is not stable and the system is in the gas phase. We calculated the phase diagram of normal 3He adsorbed on graphite at T =0 using quantum Monte Carlo methods. Considering a fully corrugated substrate, we observe that at densities lower than 0.006 Å-2 the system is a very dilute gas that, at that density, is in equilibrium with a liquid of density 0.014 Å-2 . Our prediction matches very well the recent experimental findings on the same system. On the contrary, when a flat substrate is considered, no gas-liquid coexistence is found, in agreement with previous calculations. We also report results on the different solid structures, and on the corresponding phase transitions that appear at higher densities.

  17. Mechanisms of Neutral and Anionic Surfactant Sorption to Solid-Phase Microextraction Fibers.

    PubMed

    Haftka, Joris J-H; Hammer, Jort; Hermens, Joop L M

    2015-09-15

    Octanol-water partitioning (Kow) is considered a key parameter for hydrophobicity and is often applied in the prediction of the environmental fate and exposure of neutral organic compounds. However, surfactants can create difficulties in the determination of Kow because of emulsification of both water and octanol phases. Moreover, not only is sorption behavior of ionic surfactants related to hydrophobicity, but also other interactions are relevant in sorption processes. A different approach to develop parameters that can be applied in predictive modeling of the fate of surfactants in the environment is therefore required. Distribution between solid-phase microextraction (SPME) fibers and water was used in this study to measure the affinity of surfactants to a hydrophobic phase. Fiber-water sorption coefficients of alcohol ethoxylates, alkyl carboxylates, alkyl sulfates, and alkyl sulfonates were determined at pH 7 by equilibration of the test analytes between fiber and water. Distribution between fiber and water of anionic compounds with pKa ∼ 5 (i.e., alkyl carboxylates) was dominated by the neutral fraction. Anionic surfactants with pKa ≤ 2 (i.e., alkyl sulfates and alkyl sulfonates) showed strong nonlinear distribution to the fiber. The fiber-water sorption coefficients for alcohol ethoxylates and alkyl sulfates showed a linear trend with bioconcentration factors from the literature. Fiber-water sorption coefficients are promising as a parameter to study the effects of hydrophobicity and other potential interactions on sorption behavior of neutral and anionic surfactants.

  18. Molecularly imprinted solid-phase extraction for the determination of fenitrothion in tomatoes.

    PubMed

    Pereira, Leandro Alves; Rath, Susanne

    2009-02-01

    Organophosphorus insecticides are widely employed in agriculture, and residues of them can remain after harvesting or storage. Pesticide residue control is an important task for ensuring food safety. Common chromatographic methods used in the determination of pesticide residues in food require clean-up and concentration steps prior to quantitation. While solid-phase extraction has been widely employed for this purpose, there is a need to improve selectivity. Due to their inherent biomimetic recognition systems, molecularly imprinted polymers (MIP) allow selectivity to be enhanced while keeping the costs of analysis low. In this work, a MIP that was designed to enable the selective extraction of fenitrothion (FNT) from tomatoes was synthesized using a noncovalent imprinting approach. The polymer was prepared using methacrylic acid as functional monomer and ethyleneglycol dimethacrylate as crosslinking monomer in dichloromethane (a porogenic solvent). The polymer was characterized by Fourier transform infrared spectroscopy, solid-state nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and nitrogen sorption porosimetry. The pore structure and the surface area were evaluated using the BET adsorption method. To characterize the batch rebinding behavior of the MIP, the adsorption isotherm was measured, allowing the total number of binding sites, the average binding affinity and the heterogeneity index to be established. A voltammetric method of quantifying FNT during the molecularly imprinted solid-phase extraction (MISPE) studies was developed. The polymer was placed in extraction cartridges which were then used to clean up and concentrate FNT in tomato samples prior to high-performance liquid chromatographic quantitation. The material presented a medium extraction efficiency of 59% (for analyses performed with three different cartridges on three days and a fortification level of 5.0 microg g(-1)) and selectivity when used in the preparation of

  19. Electrostatic levitation studies of supercooled liquids and metastable solid phases

    NASA Astrophysics Data System (ADS)

    Rustan, Gustav Errol

    been carried out to study the metastable phase formation in an Fe83B17 near eutectic alloy. Initial supercooling measurements using the ISU-ESL identified the formation of three metastable phases: a precipitate phase that shows stable coexistence with the deeply supercooled liquid, and two distinct bulk solidification phases. To identify the structure of the metastable phases, the Washington University Beamline ESL (WU-BESL) has been used to perform in-situ high energy x-ray diffraction measurements of the metastable phases. Based on the x-ray results, the precipitate phase has been identified as bcc-Fe, and the more commonly occurring bulk solidification product has been found to be a two-phase mixture of Fe23B6 plus fcc-Fe, which appears, upon cooling, to transform into a three phase mixture of Fe23B6, bcc-Fe, and an as-yet unidentified phase, with the transformation occurring at approximately the expected fcc-to-bcc transformation temperature of pure Fe. To further characterize the multi-phase metastable alloy, the ISU-ESL has been used to perform measurements of volume thermal expansion via the videographic technique, as well as RF susceptibility via the TDO technique. The results of the thermal expansion and susceptibility data have been found to be sensitive indicators of additional structural changes that may be occurring in the metastable solid at temperatures below 1000 K, and the susceptibility data has revealed that three distinct ferromagnetic phase transitions take place within the multi-phase mixture. Based on these results, it has been hypothesized that there may be an additional transformation taking place that leads to the formation of either bct- or o-Fe3B in addition to the Fe23B6 phase, although further work is required to test this hypothesis.

  20. Powder metallurgy: Solid and liquid phase sintering of copper

    NASA Technical Reports Server (NTRS)

    Sheldon, Rex; Weiser, Martin W.

    1993-01-01

    Basic powder metallurgy (P/M) principles and techniques are presented in this laboratory experiment. A copper based system is used since it is relatively easy to work with and is commercially important. In addition to standard solid state sintering, small quantities of low melting metals such as tin, zinc, lead, and aluminum can be added to demonstrate liquid phase sintering and alloy formation. The Taguchi Method of experimental design was used to study the effect of particle size, pressing force, sintering temperature, and sintering time. These parameters can be easily changed to incorporate liquid phase sintering effects and some guidelines for such substitutions are presented. The experiment is typically carried out over a period of three weeks.

  1. Nucleation of the diamond phase in aluminium-solid solutions

    NASA Technical Reports Server (NTRS)

    Hornbogen, E.; Mukhopadhyay, A. K.; Starke, E. A., Jr.

    1993-01-01

    Precipitation was studied from fcc solid solutions with silicon, germanium, copper and magnesium. Of all these elements only silicon and germanium form diamond cubic (DC) precipitates in fcc Al. Nucleation of the DC structure is enhanced if both types of atom are dissolved in the fcc lattice. This is interpreted as due to atomic size effects in the prenucleation stage. There are two modes of interference of fourth elements with nucleation of the DC phase in Al + Si, Ge. The formation of the DC phase is hardly affected if the atoms (for example, copper) are rejected from the (Si, Ge)-rich clusters. If additional types of atom are attracted by silicon and/or germanium, DC nuclei are replaced by intermetallic compounds (for example Mg2Si).

  2. Solid-phase differential display and bacterial expression systems in selection and functional analysis of cDNAs.

    PubMed

    Ståhl, S; Odeberg, J; Larsson, M; Røsok, O; Ree, A H; Lundeberg, J

    1999-01-01

    Differential gene expression can be expected during activation and differentiation of cells as well as during pathological conditions, such as cancer. A number of strategies have been described to identify and understand isolated differentially expressed genes. The differential display methodology has rapidly become a widely used technique to identify differentially expressed mRNAs. In this chapter we described a variant of the differential display method based on solid-phase technology. The solid-phase procedure offers an attractive alternative to solution-based differential display because minute amounts of sample can be analyzed in considerably less time than previously. The employed solid support, monodisperse super paramagnetic beads, which circumvents precipitation and centrifugations steps, has also allowed for optimization of the critical enzymatic and preparative steps in the differential display methodology. We also described how bacterial expression can be used as a means to elucidate gene function. An efficient dual-expression system was presented, together with a basic concept describing how parallel expression of selected portions of cDNAs can be used for production of cDNA-encoded proteins as parts of affinity-tagged fusion proteins. The fusion proteins are suitable both for the generation of antibodies reactive to the target cDNA-encoded protein and for the subsequent affinity enrichment of such antibodies. Affinity-enriched antibodies have proved to be valuable tools in various assays, including immunoblotting and immunocytochemical staining, and can thus be used to localize the target cDNA-encoded protein to certain cells in a tissue section or even to a specific cell compartment or organelle within a cell. High-resolution localization of a cDNA-encoded protein would provide valuable information toward the understanding of protein function. PMID:10349662

  3. Kinetics of (beta)(right arrow)(delta) Solid-Solid Phase Transition of HMX

    SciTech Connect

    Weese, R K

    2000-09-01

    In order to calculate the kinetic parameters from DSC data, we have used the generally accepted methods of Bershtein [13]. We have calculated the rate constants for 4 temperatures and the activation energy based on the shift in the transition temperature, {beta} {yields} {delta} for HMX. The values of E{sub a} from this work is 402 kJ/mol compared to previous results by Brill [9] of 204 kJ/mol. Brill and associates measured the phase transition of HMX using FTIR, sodium chloride plates and silicon oil. Given the differences in technique between FTIR and DSC the results found in this work are reasonable. In this investigation a large sample set (16) proved to be statistically valid for the determinations of k. Linear regressions were performed, observed and good fits were obtained, for each temperature. The enthalpy determination of {Delta}H{sub o}, for the {beta} {yields} {delta} phase transition was reproducible with in 3 parts in 100 over the range of this experiment. Thus, the data derived from this experiment k, E{sub a}, and {Delta}H{sub o} are valid parameters for the solid-solid phase transition. Obtaining pure {beta} phase HMX was very important for this investigation. Related to the phase change is the particle size distribution and is presented in Figure 3. Compared to previous work on HMX, this study utilized very pure {beta} phase material. In addition, the particle size was controlled more rigorously at about 160 {micro}m, giving a more consistent result for {alpha}. Thus, these kinetic results should have less scatter than results with less control of HMX purity and particle size. The kinetic basis of the polymorphic conversion is due to the cohesive forces in the HMX crystal lattice [21]. The energy required to bring about change from chair to chair-chair conformation has been reported by Brill [21] as ring torsion and is essentially a normal mode of the molecule that requires about 4 kJ mol{sup -1}. For the purpose of this investigation the energy

  4. [Determination of aflatoxins in hot chilli products by matrix solid-phase dispersion and liquid chromatography].

    PubMed

    Zheng, Ping; Sheng, Xuan; Yu, Xiaofeng; Hu, Yanyun

    2006-01-01

    A new method based on matrix solid-phase dispersion (MSPD) extraction with neutral alumina and co-column purification with graphitized carbon black has been developed to determine aflatoxins B1, B2, G1, G2 in hot chilli products. The method includes liquid chromatography and fluorescence detection with on-line post-column derivatization with bromine. Optimization of different parameters, such as the type of solid supports for matrix dispersion and co-column clean-up was carried out. The recoveries of aflatoxins B1, B2, G1 and G2 were 95.4%, 87.3%, 91.5% and 92.6%, respectively, with relative standard deviations ranging from 3.3% to 6.1%. The limits of detection were in the range of 0.10 ng/g (B2, G2) to 0.25 ng/g (B1, G1). In addition, the comparison of the extraction and purification effect of MSPD with immunity affinity column showed that, MSPD is a valid method to analyze aflatoxins in hot chilli products.

  5. Solid phase extraction of food contaminants using molecular imprinted polymers.

    PubMed

    Baggiani, Claudio; Anfossi, Laura; Giovannoli, Cristina

    2007-05-15

    Food contamination from natural or anthropogenic sources poses severe risks to human health. It is now largely accepted that continuous exposure to low doses of toxic chemicals can be related to several chronic diseases, including some type of cancer and serious hormonal dysfunctions. Contemporary analytical methods have the sensitivity required for contamination detection and quantification, but direct application of these methods on food samples can be rarely performed. In fact, the matrix introduces severe disturbances, and analysis can be performed only after some clean-up and preconcentration steps. Current sample pre-treatment methods, mostly based on the solid phase extraction technique, are very fast and inexpensive but show a lack of selectivity, while methods based on immunoaffinity extraction are very selective but expensive and not suitable for harsh environments. Thus, inexpensive, rapid and selective clean-up methods, relaying on "intelligent" materials are needed. Recent years have seen a significant increase of the "molecularly imprinted solid phase extraction" (MISPE) technique in the food contaminant analysis. In fact, this technique seems to be particularly suitable for extractive applications where analyte selectivity in the presence of very complex and structured matrices represents the main problem. In this review, several applications of MISPE in food contamination analysis will be discussed, with particular emphasis on the extraction of pesticides, drugs residua, mycotoxins and environmental contaminants.

  6. Effects of sample homogenization on solid phase sediment toxicity

    SciTech Connect

    Anderson, B.S.; Hunt, J.W.; Newman, J.W.; Tjeerdema, R.S.; Fairey, W.R.; Stephenson, M.D.; Puckett, H.M.; Taberski, K.M.

    1995-12-31

    Sediment toxicity is typically assessed using homogenized surficial sediment samples. It has been recognized that homogenization alters sediment integrity and may result in changes in chemical bioavailability through oxidation-reduction or other chemical processes. In this study, intact (unhomogenized) sediment cores were taken from a Van Veen grab sampler and tested concurrently with sediment homogenate from the same sample in order to investigate the effect of homogenization on toxicity. Two different solid-phase toxicity test protocols were used for these comparisons. Results of amphipod exposures to samples from San Francisco Bay indicated minimal difference between intact and homogenized samples. Mean amphipod survival in intact cores relative to homogenates was similar at two contaminated sites. Mean survival was 34 and 33% in intact and homogenized samples, respectively, at Castro Cove. Mean survival was 41% and 57%, respectively, in intact and homogenized samples from Islais Creek. Studies using the sea urchin development protocol, modified for testing at the sediment/water interface, indicated considerably more toxicity in intact samples relative to homogenized samples from San Diego Bay. Measures of metal flux into the overlying water demonstrated greater flux of metals from the intact samples. Zinc flux was five times greater, and copper flux was twice as great in some intact samples relative to homogenates. Future experiments will compare flux of metals and organic compounds in intact and homogenized sediments to further evaluate the efficacy of using intact cores for solid phase toxicity assessment.

  7. Hyperdoping silicon with selenium: solid vs. liquid phase epitaxy

    PubMed Central

    Zhou, Shengqiang; Liu, Fang; Prucnal, S.; Gao, Kun; Khalid, M.; Baehtz, C.; Posselt, M.; Skorupa, W.; Helm, M.

    2015-01-01

    Chalcogen-hyperdoped silicon shows potential applications in silicon-based infrared photodetectors and intermediate band solar cells. Due to the low solid solubility limits of chalcogen elements in silicon, these materials were previously realized by femtosecond or nanosecond laser annealing of implanted silicon or bare silicon in certain background gases. The high energy density deposited on the silicon surface leads to a liquid phase and the fast recrystallization velocity allows trapping of chalcogen into the silicon matrix. However, this method encounters the problem of surface segregation. In this paper, we propose a solid phase processing by flash-lamp annealing in the millisecond range, which is in between the conventional rapid thermal annealing and pulsed laser annealing. Flash lamp annealed selenium-implanted silicon shows a substitutional fraction of ~ 70% with an implanted concentration up to 2.3%. The resistivity is lower and the carrier mobility is higher than those of nanosecond pulsed laser annealed samples. Our results show that flash-lamp annealing is superior to laser annealing in preventing surface segregation and in allowing scalability. PMID:25660096

  8. Hyperdoping silicon with selenium: solid vs. liquid phase epitaxy.

    PubMed

    Zhou, Shengqiang; Liu, Fang; Prucnal, S; Gao, Kun; Khalid, M; Baehtz, C; Posselt, M; Skorupa, W; Helm, M

    2015-01-01

    Chalcogen-hyperdoped silicon shows potential applications in silicon-based infrared photodetectors and intermediate band solar cells. Due to the low solid solubility limits of chalcogen elements in silicon, these materials were previously realized by femtosecond or nanosecond laser annealing of implanted silicon or bare silicon in certain background gases. The high energy density deposited on the silicon surface leads to a liquid phase and the fast recrystallization velocity allows trapping of chalcogen into the silicon matrix. However, this method encounters the problem of surface segregation. In this paper, we propose a solid phase processing by flash-lamp annealing in the millisecond range, which is in between the conventional rapid thermal annealing and pulsed laser annealing. Flash lamp annealed selenium-implanted silicon shows a substitutional fraction of ~ 70% with an implanted concentration up to 2.3%. The resistivity is lower and the carrier mobility is higher than those of nanosecond pulsed laser annealed samples. Our results show that flash-lamp annealing is superior to laser annealing in preventing surface segregation and in allowing scalability. PMID:25660096

  9. Electrochemically controlled in-tube solid phase microextraction.

    PubMed

    Ahmadi, Seyyed Hamid; Manbohi, Ahmad; Heydar, Kourosh Tabar

    2015-01-01

    We report a new in-tube solid phase microextraction approach named electrochemically controlled in-tube solid phase microextraction (EC in-tube SPME). This approach, which combined electrochemistry and in-tube SPME, led to decrease in total analysis time and increase in sensitivity. At first, pyrrole was elctropolymerized on the inner surface of a stainless steel tube. Then, the polypyrrole (PPy)-coated in-tube SPME was coupled on-line to liquid chromatography (HPLC) to achieve automated in-tube SPME-HPLC analysis. After the completion of EC-in-tube SPME-HPLC setup, the PPy-coated tube was used as working electrode for uptake of diclofenac as target analyte. Extraction ability of the tube in presence and in absence of applied electrical field was investigated. It was found that, under the same extraction conditions, the extraction efficiency could be greatly enhanced by using the constant potential. Important factors are also optimized. The detection limit (S/N=3) and precision were 0.1 μg L(-1) and 4.4%, respectively.

  10. Studies of phase transitions in the aripiprazole solid dosage form.

    PubMed

    Łaszcz, Marta; Witkowska, Anna

    2016-01-01

    Studies of the phase transitions in an active substance contained in a solid dosage form are very complicated but essential, especially if an active substance is classified as a BCS Class IV drug. The purpose of this work was the development of sensitive methods for the detection of the phase transitions in the aripiprazole tablets containing initially its form III. Aripiprazole exhibits polymorphism and pseudopolymorphism. Powder diffraction, Raman spectroscopy and differential scanning calorimetry methods were developed for the detection of the polymorphic transition between forms III and I as well as the phase transition of form III into aripiprazole monohydrate in tablets. The study involved the initial 10 mg and 30 mg tablets, as well as those stored in Al/Al blisters, a triplex blister pack and HDPE bottles (with and without desiccant) under accelerated and long term conditions. The polymorphic transition was not observed in the initial and stored tablets but it was visible on the DSC curve of the Abilify(®) 10 mg reference tablets. The formation of the monohydrate was observed in the diffractograms and Raman spectra in the tablets stored under accelerated conditions. The monohydrate phase was not detected in the tablets stored in the Al/Al blisters under long term conditions. The results showed that the Al/Al blisters can be recommended as the packaging of the aripiprazole tablets containing form III. PMID:26397209

  11. Studies of phase transitions in the aripiprazole solid dosage form.

    PubMed

    Łaszcz, Marta; Witkowska, Anna

    2016-01-01

    Studies of the phase transitions in an active substance contained in a solid dosage form are very complicated but essential, especially if an active substance is classified as a BCS Class IV drug. The purpose of this work was the development of sensitive methods for the detection of the phase transitions in the aripiprazole tablets containing initially its form III. Aripiprazole exhibits polymorphism and pseudopolymorphism. Powder diffraction, Raman spectroscopy and differential scanning calorimetry methods were developed for the detection of the polymorphic transition between forms III and I as well as the phase transition of form III into aripiprazole monohydrate in tablets. The study involved the initial 10 mg and 30 mg tablets, as well as those stored in Al/Al blisters, a triplex blister pack and HDPE bottles (with and without desiccant) under accelerated and long term conditions. The polymorphic transition was not observed in the initial and stored tablets but it was visible on the DSC curve of the Abilify(®) 10 mg reference tablets. The formation of the monohydrate was observed in the diffractograms and Raman spectra in the tablets stored under accelerated conditions. The monohydrate phase was not detected in the tablets stored in the Al/Al blisters under long term conditions. The results showed that the Al/Al blisters can be recommended as the packaging of the aripiprazole tablets containing form III.

  12. IHPRPT Phase I Solid Boost Demonstrator: A Success Story

    NASA Astrophysics Data System (ADS)

    Glaittli, Steven R.

    2001-06-01

    The integrated High-Payoff Rocket Propulsion Technology or IHPRPT program seeks to double the launch capability of the United States by the year 2010. The program is organized into three phases, with a technology demonstrator at the end of each phase. The IHPRPT Phase I Solid Boost Demonstrator Program is presented. Materials and processing technologies developed under the IHPRPT program and on other contracted technology and privately funded programs were combined into one full-scale booster demonstrator culminating six years of new technology work. New materials and processes were used in all components of the demonstration motor to achieve the cost and performance goals identified for the Phase I Boost & Orbit Transfer Propulsion mission area in the IHPRPT program. New materials utilized in the motor included low cost high performance carbon fibers in the composite case energetic ingredients in the propellant. net molded structural parts in the nozzle. and an all-new electromechanical Thrust Vector Actuation (TVA) system. The demonstrator was successfully static tested on 16 November 2000 The static test has been heralded as a success by government and industry observers alike.

  13. Selecting polymers for two-phase partitioning bioreactors (TPPBs): Consideration of thermodynamic affinity, crystallinity, and glass transition temperature.

    PubMed

    Bacon, Stuart L; Peterson, Eric C; Daugulis, Andrew J; Parent, J Scott

    2015-01-01

    Two-phase partitioning bioreactor technology involves the use of a secondary immiscible phase to lower the concentration of cytotoxic solutes in the fermentation broth to subinhibitory levels. Although polymeric absorbents have attracted recent interest due to their low cost and biocompatibility, material selection requires the consideration of properties beyond those of small molecule absorbents (i.e., immiscible organic solvents). These include a polymer's (1) thermodynamic affinity for the target compound, (2) degree of crystallinity (wc ), and (3) glass transition temperature (Tg ). We have examined the capability of three thermodynamic models to predict the partition coefficient (PC) for n-butyric acid, a fermentation product, in 15 polymers. Whereas PC predictions for amorphous materials had an average absolute deviation (AAD) of ≥16%, predictions for semicrystalline polymers were less accurate (AAD ≥ 30%). Prediction errors were associated with uncertainties in determining the degree of crystallinity within a polymer and the effect of absorbed water on n-butyric acid partitioning. Further complications were found to arise for semicrystalline polymers, wherein strongly interacting solutes increased the polymer's absorptive capacity by actually dissolving the crystalline fraction. Finally, we determined that diffusion limitations may occur for polymers operating near their Tg , and that the Tg can be reduced by plasticization by water and/or solute. This study has demonstrated the impact of basic material properties that affects the performance of polymers as sequestering phases in TPPBs, and reflects the additional complexity of polymers that must be taken into account in material selection. PMID:26259846

  14. Selecting polymers for two-phase partitioning bioreactors (TPPBs): Consideration of thermodynamic affinity, crystallinity, and glass transition temperature.

    PubMed

    Bacon, Stuart L; Peterson, Eric C; Daugulis, Andrew J; Parent, J Scott

    2015-01-01

    Two-phase partitioning bioreactor technology involves the use of a secondary immiscible phase to lower the concentration of cytotoxic solutes in the fermentation broth to subinhibitory levels. Although polymeric absorbents have attracted recent interest due to their low cost and biocompatibility, material selection requires the consideration of properties beyond those of small molecule absorbents (i.e., immiscible organic solvents). These include a polymer's (1) thermodynamic affinity for the target compound, (2) degree of crystallinity (wc ), and (3) glass transition temperature (Tg ). We have examined the capability of three thermodynamic models to predict the partition coefficient (PC) for n-butyric acid, a fermentation product, in 15 polymers. Whereas PC predictions for amorphous materials had an average absolute deviation (AAD) of ≥16%, predictions for semicrystalline polymers were less accurate (AAD ≥ 30%). Prediction errors were associated with uncertainties in determining the degree of crystallinity within a polymer and the effect of absorbed water on n-butyric acid partitioning. Further complications were found to arise for semicrystalline polymers, wherein strongly interacting solutes increased the polymer's absorptive capacity by actually dissolving the crystalline fraction. Finally, we determined that diffusion limitations may occur for polymers operating near their Tg , and that the Tg can be reduced by plasticization by water and/or solute. This study has demonstrated the impact of basic material properties that affects the performance of polymers as sequestering phases in TPPBs, and reflects the additional complexity of polymers that must be taken into account in material selection.

  15. Solid Phase Characterization of Tank 241-C-108 Residual Waste Solids Samples

    SciTech Connect

    Cooke, Gary A.; Pestovich, John A.; Huber, Heinz J.

    2013-05-29

    This report presents the results for solid phase characterization (SPC) of solid samples removed from tank 241-C-108 (C-108) on August 12-13,2012, using the off-riser sampler. Samples were received at the 222-S Laboratory on August 13 and were described and photographed. The SPC analyses that were performed include scanning electron microscopy (SEM) using the ASPEX(R)l scanning electron microscope, X-ray diffraction (XRD) using the Rigaku(R) 2 MiniFlex X-ray diffractometer, and polarized light microscopy (PLM) using the Nikon(R) 3 Eclipse Pol optical microscope. The SEM is equipped with an energy dispersive X-ray spectrometer (EDS) to provide chemical information. Gary A. Cooke conducted the SEM analysis, John A. Pestovich performed the XRD analysis, and Dr. Heinz J. Huber performed the PLM examination. The results of these analyses are presented here.

  16. Modified phase-field-crystal model for solid-liquid phase transitions

    NASA Astrophysics Data System (ADS)

    Guo, Can; Wang, Jincheng; Wang, Zhijun; Li, Junjie; Guo, Yaolin; Tang, Sai

    2015-07-01

    A modified phase-field-crystal (PFC) model is proposed to describe solid-liquid phase transitions by reconstructing the correlation function. The effects of fitting parameters of our modified PFC model on the bcc-liquid phase diagram, numerical stability, and solid-liquid interface properties during planar interface growth are examined carefully. The results indicate that the increase of the correlation function peak width at k =km will enhance the stability of the ordered phase, while the increase of peak height at k =0 will narrow the two-phase coexistence region. The third-order term in the free-energy function and the short wave-length of the correlation function have significant influences on the numerical stability of the PFC model. During planar interface growth, the increase of peak width at k =km will decrease the interface width and the velocity coefficient C , but increase the anisotropy of C and the interface free energy. Finally, the feasibility of the modified phase-field-crystal model is demonstrated with a numerical example of three-dimensional dendritic growth of a body-centered-cubic structure.

  17. Modified phase-field-crystal model for solid-liquid phase transitions.

    PubMed

    Guo, Can; Wang, Jincheng; Wang, Zhijun; Li, Junjie; Guo, Yaolin; Tang, Sai

    2015-07-01

    A modified phase-field-crystal (PFC) model is proposed to describe solid-liquid phase transitions by reconstructing the correlation function. The effects of fitting parameters of our modified PFC model on the bcc-liquid phase diagram, numerical stability, and solid-liquid interface properties during planar interface growth are examined carefully. The results indicate that the increase of the correlation function peak width at k=k(m) will enhance the stability of the ordered phase, while the increase of peak height at k=0 will narrow the two-phase coexistence region. The third-order term in the free-energy function and the short wave-length of the correlation function have significant influences on the numerical stability of the PFC model. During planar interface growth, the increase of peak width at k=k(m) will decrease the interface width and the velocity coefficient C, but increase the anisotropy of C and the interface free energy. Finally, the feasibility of the modified phase-field-crystal model is demonstrated with a numerical example of three-dimensional dendritic growth of a body-centered-cubic structure. PMID:26274309

  18. Molecularly imprinted polymers-curcuminoids and its application for solid phase extraction

    NASA Astrophysics Data System (ADS)

    Wulandari, Meyliana; Amran, M. B.; Lopez, A. B. Descalzo; Urraca, J. L.; Moreno-Bondi, M. C.

    2014-03-01

    Molecularly Imprinted Polymers (MIPs) for the selective recognition properties of curcumin (CUR), a cancer chemopreventive agent were obtained by a non-covalent imprinting approach with bisdemetoxycurcumin (BDMC) as the template molecule. The double bond of BDMC has been reduced in order not to be involved in polymerization and make the template molecules easy to be eluted. Several functional monomers have been evaluated to maximize the interactions with the template molecule during polymerization. MIPs prepared by bulk of N-(2-aminoethyl) metacrylamid hydrochlorideas functional monomer, ethylene glycol dimethacrylate as crosslinker, 2,2'-azobis (2'4-dimethyl valeronitril) as initiator and acetonitrile as porogen. Non-imprinted polymer (NIP) have been also synthesized for reference purposes. UV-vis spectroscopy has been used to predict the template to functional monomer ratio which indicates the formation of 2:1 complexes between monomer and curcumin and the association constants (K11 = 2529 μM and K12 = 1960.75 μM in acetonitrile). The capacity and imprinting factor have been evaluated as stationary phases in high-pressure liquid chromatography to CUR and BDMC. The binding properties and the homogeneity of the binding sites of the different polymers have been studied by Freundlich isotherm modeling and weight average affinity and number of binding sites. One of the foremost applications of molecular imprinting has been in molecularly imprinted solid phase extraction and it has the ability to separate and preconcentrate between closely related compounds in curcuminoids.

  19. Application of low-temperature glassy carbon films in solid-phase microextraction.

    PubMed

    Giardina, M; Olesik, S V

    2001-12-15

    Low-temperature glassy carbon (LTGC) films were investigated as a sorbent coating for solid-phase microextraction because of its uniquely selective adsorptive characteristics. The selectivity of these coatings is primarily controlled by shape characteristics of the solute molecule and the final processing temperature used to form the LTGC, demonstrating unique adsorptive characteristics compared to commercial phases. The LTGC films were prepared by first coating porous silica particles with a diethylnyl oligomer precursor and then heat curing at temperatures between 300 and 1000 degrees C to form the LTGC. Then, using a sol-gel process, the LTGC-coated silica particles were immobilized onto stainless steel fibers and subsequently used for headspace and liquid extractions followed by GC-FID analysis. The selectivity of the LTGC is demonstrated by the extraction of a variety of aromatic hydrocarbons as well as the taste and odor contaminants geosmin, 2-methylisoborneol, and 2,4,6-trichloroanisole commonly found in water supplies. The data show that the LTGC coating has the highest affinity for molecules with the greatest cross-sectional surface area and polarizability and that this selective mechanism increases as a function of LTGC processing temperature. PMID:11791552

  20. Ferrofluid-based dispersive solid phase extraction of palladium.

    PubMed

    Farahani, Malihe Davudabadi; Shemirani, Farzaneh; Gharehbaghi, Maysam

    2013-05-15

    A new mode of dispersive solid phase extraction based on ferrofluid has been developed. In this method, an appropriate amount of ferrofluid is injected rapidly into the aqueous sample by a syringe. Since the sorbent is highly dispersed in the aqueous phase, extraction can be achieved within a few seconds. The ferrofluid can be attracted by a magnet and no centrifugation step is needed for phase separation. Palladium was used as a model compound in the development and evaluation of the extraction procedure in combination with flame atomic absorption spectrometry. The experimental parameters (pH, DDTC concentration, type and concentration of eluent, the amount of adsorbent, extraction time, and the effect of interfering ions) were investigated in detail. Under the optimized conditions, the calibration graph was linear over the range of 1-100 μg L(-1) and relative standard deviation of 3.3% at 0.1 μg mL(-1) was obtained (n=7). The limit of detection and enrichment factor (EF) was obtained to be 0.35 μg L(-1) and 267, respectively. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 24.6 mg g(-1) for Pd(II). The method was validated using certified reference material, and has been applied for the determination of trace Pd(II) in actual samples with satisfactory results. PMID:23618148

  1. System for exchange of hydrogen between liquid and solid phases

    DOEpatents

    Reilly, James J.; Grohse, Edward W.; Johnson, John R.; Winsche, deceased, Warren E.

    1988-01-01

    The reversible reaction M+x/2 H.sub.2 .rarw..fwdarw.MH.sub.x, wherein M is a reversible metal hydride former that forms a hydride MH.sub.x in the presence of H.sub.2, generally used to store and recall H.sub.2, is found to proceed under an inert liquid, thereby reducing contamination, providing better temperature control, providing in situ mobility of the reactants, and increasing flexibility in process design. Thus, a slurry of particles of a metal hydride former with an inert solvent is subjected to a temperature and pressure controlled atmosphere containing H.sub.2, to store hydrogen and to release previously stored hydrogen. The direction of the flow of the H.sub.2 through the liquid is dependent upon the H.sub.2 pressure in the gas phase at a given temperature. When the actual H.sub.2 pressure is above the equilibrium absorption pressure of the respective hydride the reaction proceeds to the right, i.e., the metal hydride is formed and hydrogen is stored in the solid particles. When the actual pressure in the gas phase is below the equilibrium dissociation pressure of the respective hydride the reaction proceeds to the left, the metal hydride is decomposed and hydrogen is released into the gas phase.

  2. System for exchange of hydrogen between liquid and solid phases

    DOEpatents

    Reilly, J.J.; Grohse, E.W.; Johnson, J.R.; Winsche, W.E.

    1985-02-22

    The reversible reaction M + x/2 H/sub 2/ reversible MH/sub x/, wherein M is a reversible metal hydride former that forms a hydride MH/sub x/ in the presence of H/sub 2/, generally used to store and recall H/sub 2/, is found to proceed under an inert liquid, thereby reducing contamination, providing better temperature control, providing in situ mobility of the reactants, and increasing flexibility in process design. Thus, a slurry of particles of a metal hydride former with an inert solvent is subjected to a temperature and pressure controlled atmosphere containing H/sub 2/, to store hydrogen and to release previously stored hydrogen. The direction of the flow of the H/sub 2/ through the liquid is dependent upon the H/sub 2/ pressure in the gas phase at a given temperature. When the actual H/sub 2/ pressure is above the equilibrium absorption pressure of the respective hydride the reaction proceeds to the right, i.e., the metal hydride is formed and hydrogen is stored in the solid particle. When the actual pressure in the gas phase is below the equilibrium dissociation pressure of the respective hydride the reaction proceeds to the left, the metal hydride is decomposed and hydrogen is released into the gas phase.

  3. Antibody-based affinity cryo-EM grid.

    PubMed

    Yu, Guimei; Li, Kunpeng; Jiang, Wen

    2016-05-01

    The Affinity Grid technique combines sample purification and cryo-Electron Microscopy (cryo-EM) grid preparation into a single step. Several types of affinity surfaces, including functionalized lipids monolayers, streptavidin 2D crystals, and covalently functionalized carbon surfaces have been reported. More recently, we presented a new affinity cryo-EM approach, cryo-SPIEM, which applies the traditional Solid Phase Immune Electron Microscopy (SPIEM) technique to cryo-EM. This approach significantly simplifies the preparation of affinity grids and directly works with native macromolecular complexes without need of target modifications. With wide availability of high affinity and high specificity antibodies, the antibody-based affinity grid would enable cryo-EM studies of the native samples directly from cell cultures, targets of low abundance, and unstable or short-lived intermediate states.

  4. Finite-temperature Wigner solid and other phases of ripplonic polarons on a helium film

    NASA Astrophysics Data System (ADS)

    Klimin, Serghei N.; Tempere, Jacques; Misko, Vyacheslav R.; Wouters, Michiel

    2016-07-01

    Electrons on liquid helium can form different phases depending on density, and temperature. Also the electron-ripplon coupling strength influences the phase diagram, through the formation of so-called "ripplonic polarons", that change how electrons are localized, and that shifts the transition between the Wigner solid and the liquid phase. We use an all-coupling, finite-temperature variational method to study the formation of a ripplopolaron Wigner solid on a liquid helium film for different regimes of the electron-ripplon coupling strength. In addition to the three known phases of the ripplopolaron system (electron Wigner solid, polaron Wigner solid, and electron fluid), we define and identify a fourth distinct phase, the ripplopolaron liquid. We analyse the transitions between these four phases and calculate the corresponding phase diagrams. This reveals a reentrant melting of the electron solid as a function of temperature. The calculated regions of existence of the Wigner solid are in agreement with recent experimental data.

  5. Method for preparing a solid phase microextraction device using aerogel

    DOEpatents

    Miller, Fred S.; Andresen, Brian D.

    2006-10-24

    A sample collection substrate of aerogel and/or xerogel materials bound to a support structure is used as a solid phase microextraction (SPME) device. The xerogels and aerogels may be organic or inorganic and doped with metals or other compounds to target specific chemical analytes. The support structure is typically formed of a glass fiber or a metal wire (stainless steel or kovar). The devices are made by applying gel solution to the support structures and drying the solution to form aerogel or xerogel. Aerogel particles may be attached to the wet layer before drying to increase sample collection surface area. These devices are robust, stable in fields of high radiation, and highly effective at collecting gas and liquid samples while maintaining superior mechanical and thermal stability during routine use. Aerogel SPME devices are advantageous for use in GC/MS analyses due to their lack of interfering background and tolerance of GC thermal cycling.

  6. Gold nanoshells as solid-phase dot assay labels

    NASA Astrophysics Data System (ADS)

    Khlebtsov, Boris N.; Dykman, Lev A.; Bogatyrev, Vadimir A.; Khlebtsov, Nikolai G.

    2007-05-01

    We report on the first application of silica-gold nanoshells to a solid-phase dot immunoassay. The assay principle is based on staining of a drop (1μL ) analyte on a nitrocellulose membrane strip by using silica/gold nanoshells conjugated with biospecific probing molecules. Experimental example is human IgG (hIgG, target molecules) and protein A (probing molecules). For usual 15-nm colloidal gold conjugates, the minimal detectable amount of hIgG is about 4ng. By contrast, for nanoshell conjugates (silica core diameter of 70 nm and gold outer diameter of 100 nm) we have found significant increase in detection sensitivity and the minimal detectable amount of hIgG is about 0.5 ng.

  7. Solid phase indirect radioimmunoassay: standardization and applications in viral serology.

    PubMed

    Yung, L L; Loh, W; ter Meulen, V

    1977-07-18

    In solid phase indirect radioimmunoassay (IRIA) antiviral immunoglobulins (Ig) bind specifically to the viral antigen fixed onto wells of microtiter plates. Radioactively labeled (125I) anti-Ig can be used to detect these antiviral antibodies. The sensitivity of the IRIA depends on the amount of antigen in the microtiter wells and the concentration of the 125I-labeled anti-Ig used. To standardize the assay, a method of antigen titration in the IRIA was devised, using parainfluenza type 1 viruses as antigens. The IRIA provides a means to titrate viral antigens with different biologic activities and antibodies against them. A binding inhibition test (BIT) based on IRIA allows the antigenic analysis of different virus strains, as is demonstrated for two closely related parainfluenza type 1 virus strains.

  8. Synthesis of phytochelatins by the continuous flow solid phase procedure.

    PubMed

    Chen, Z; Hemmasi, B

    1993-11-01

    A nona- and an undecapeptide corresponding to phytochelatins with the general structure H-[gamma-Glu-Cys]n-Gly-OH were each synthesized by the continuous flow solid phase method using two different methodologies. Fmoc-amino acid derivatives were used as precursors, and two different H2N-POE-PS supports were employed. Different procedures were used to remove Acm protecting groups from Cys residues. In a second synthesis, Acm groups were removed before cleavage of the peptides from the polymer supports. The partially protected peptides of the first synthesis were purified by preparative HPLC. The purity and identity of all the synthesized peptides were verified by analytical HPLC and IS-MS and in some cases by amino acid analysis. PMID:8292265

  9. Hydrogen cleavage by solid-phase frustrated Lewis pairs.

    PubMed

    Xing, Jun-Yi; Buffet, Jean-Charles; Rees, Nicholas H; Nørby, Peter; O'Hare, Dermot

    2016-08-18

    We report the direct synthesis of a solid-phase frustrated Lewis pair (s-FLP) by combining a silica-supported Lewis acid ([triple bond, length as m-dash]SiOB(C6F5)2, s-BCF) with a Lewis base (tri-tert-butylphosphine, (t)Bu3P) to give [[triple bond, length as m-dash]SiOB(C6F5)2][(t)Bu3P]. Reaction of this s-FLP with H2 under mild conditions led to heterolytic H-H bond cleavage and the formation of [[triple bond, length as m-dash]SiOB(H)(C6F5)2][(t)Bu3PH].

  10. Porous protective solid phase micro-extractor sheath

    DOEpatents

    Andresen, Brian D.; Randich, Erik

    2005-03-29

    A porous protective sheath for active extraction media used in solid phase microextraction (SPME). The sheath permits exposure of the media to the environment without the necessity of extending a fragile coated fiber from a protective tube or needle. Subsequently, the sheath can pierce and seal with GC-MS septums, allowing direct injection of samples into inlet ports of analytical equipment. Use of the porous protective sheath, within which the active extraction media is contained, mitigates the problems of: 1) fiber breakage while the fiber is extended during sampling, 2) active media coating loss caused by physical contact of the bare fiber with the sampling environment; and 3) coating slough-off during fiber extension and retraction operations caused by rubbing action between the fiber and protective needle or tube.

  11. Bench-scale solid phase biotreatment: Benfield Industries Superfund site

    SciTech Connect

    Marlowe, M.W.; Harper, T.R.; Semenak, R.K.

    1995-12-31

    The Benfield Industries, Inc. Superfund site located in Hazelwood, North Carolina has been found to have approximately 15,000 cubic yards of polycyclic aromatic hydrocarbon (PAH) contaminated soil. Risk based clean up goals were specified at the site for eight target PAH compounds including benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, chrysene, indeno(1,2,3-cd)pyrene, naphthalene, and pentachlorophenol. Treatability studies were performed to evaluate solid phase bioremediation, which includes ex-situ and in-situ land treatment processes, for treatment of the site soil. All treatments were conducted using only indigenous microorganisms maintained under aerobic conditions. Two soil samples with different levels of PAH contamination were collected from the site for use in the treatability evaluations. The two soil samples were contaminated with total PAHs at concentrations of approximately 30 milligrams per kilogram (mg/kg) and 6,000 mg/kg, respectively. Three solid phase bioremediation studies were conducted over a one and one half year period using starting concentrations of total PAHs of approximately 30; 600; and 6,000 mg/kg. The objectives of the studies included determining (1) if clean up goals could be achieved, (2) the approximate biodegradation rate of PAHs in the site soils, and (3) the optimum environmental conditions for biodegradation of the PAHs. Some of the environmental parameters which were varied during the testing included moisture levels, soil conditioners, nutrients and pH. The results of the testing indicated that total and target PAHs can be reduced by up to 90 percent in less than 50 days, depending on environmental conditions maintained in the reactors. Clean up goals for all of the target compounds were achieved at some point during the study.

  12. Municipal solid waste development phases: Evidence from EU27.

    PubMed

    Vujić, Goran; Gonzalez-Roof, Alvaro; Stanisavljević, Nemanja; Ragossnig, Arne M

    2015-12-01

    Many countries in the European Union (EU) have very developed waste management systems. Some of its members have managed to reduce their landfilled waste to values close to zero during the last decade. Thus, European Union legislation is very stringent regarding waste management for their members and candidate countries, too. This raises the following questions: Is it possible for developing and developed countries to comply with the European Union waste legislation, and under what conditions? How did waste management develop in relation to the economic development in the countries of the European Union? The correlation between waste management practices and economic development was analysed for 27 of the European Union Member States for the time period between 1995 and 2007. In addition, a regression analysis was performed to estimate landfilling of waste in relation to gross domestic product for every country. The results showed a strong correlation between the waste management variables and the gross domestic product of the EU27 members. The definition of the municipal solid waste management development phases followed a closer analysis of the relation between gross domestic product and landfilled waste. The municipal solid waste management phases are characterised by high landfilling rates at low gross domestic product levels, and landfilling rates near zero at high gross domestic product levels. Hence the results emphasize the importance of wider understanding of what is required for developing countries to comply with the European Union initiatives, and highlight the importance of allowing developing countries to make their own paths of waste management development. PMID:26574580

  13. Phosphoprotein Isotope-Coded Solid-Phase Tag Approach for Enrichment and Quantitative Analysis of Phosphopeptides from Complex Mixtures

    SciTech Connect

    Qian, Weijun ); Goshe, Michael B.; Camp, David G. ); Yu, Li-Rong ); Tang, Keqi ); Smith, Richard D. )

    2003-10-15

    Many cellular processes are regulated by reversible protein phosphorylation and the ability to identify and quantify phosphoproteins from proteomes is essential for gaining a better understanding of these dynamic cellular processes. However, a sensitive, efficient and global method capable of addressing the phosphoproteome has yet to be developed. Here we describe an improved stable-isotope labeling method using a Phosphoprotein Isotope-coded Solid-phase Tag (PhIST) for isolating and measuring the relative abundance of phosphorylated peptides from complex peptide mixtures resulting from the enzymatic digestion of extracted proteins. The PhIST approach is an extension of the previously reported Phosphoprotein Isotope-coded Affinity Tag (PhIAT)approach developed by our laboratory1-2, where the O-phosphate moiety on phosphoseryl or phosphothreonyl residues were derivatized by hydroxide ion-medated B-elimination followed by the addition of 1,2-ethanedithiol (EDT). Instead of using the biotin affinity tag, peptides containing the EDT moiety were captured and labeled in one step using isotope-coded solid-phase reagents containing either light (12C6, 14N) or heavy (13C6, 15N) stable isotopes. The captured peptides labeled with the isotope-coded tags were released from the solid-phase support by UV photocleavage and analyzed by capillary LC-MS/MS. The efficiency and sensitivity of the PhIST labeling approach for identification of phosphopeptides from mixtures was demonstrated using casein phosphoproteins. Its utility for proteomic applications is demonstrated by the labeling of soluble proteins from human breast cancer cell line.

  14. Evaluation of a molecularly imprinted polymer for determination of steroids in goat milk by matrix solid phase dispersion.

    PubMed

    Gañán, Judith; Morante-Zarcero, Sonia; Gallego-Picó, Alejandrina; Garcinuño, Rosa María; Fernández-Hernando, Pilar; Sierra, Isabel

    2014-08-01

    A molecularly imprinted polymer-matrix solid-phase dispersion methodology for simultaneous determination of five steroids in goat milk samples was proposed. Factors affecting the extraction recovery such as sample/dispersant ratio and washing and elution solvents were investigated. The molecularly imprinted polymer used as dispersant in the matrix solid-phase dispersion procedure showed high affinity to steroids, and the obtained extracts were sufficiently cleaned to be directly analyzed. Analytical separation was performed by micellar electrokinetic chromatography using a capillary electrophoresis system equipped with a diode array detector. A background electrolyte composed of borate buffer (25mM, pH 9.3), sodium dodecyl sulfate (10mM) and acetonitrile (20%) was used. The developed MIP-MSPD methodology was applied for direct determination of testosterone (T), estrone (E1), 17β-estradiol (17β-E2), 17α-ethinylestradiol (EE2) and progesterone (P) in different goat milk samples. Mean recoveries obtained ranged from 81% to 110%, with relative standard deviations (RSD)≤12%. The molecularly imprinted polymer-matrix solid-phase dispersion method is fast, selective, cost-effective and environment-friendly compared with other pretreatment methods used for extraction of steroids in milk.

  15. New methods and materials for solid phase extraction and high performance liquid chromatography

    SciTech Connect

    Dumont, P.J.

    1996-04-23

    This paper describes methods for solid phase extraction and high performance liquid chromatography (HPLC). The following are described: Effects of Resin Sulfonation on the Retention of Polar Organic Compounds in Solid Phase Extraction; Ion-Chromatographic Separation of Alkali Metals In Non-Aqueous Solvents; Cation-Exchange Chromatography in Non-Aqueous Solvents; and Silicalite As a Stationary Phase For HPLC.

  16. Phase diagrams and kinetics of solid-liquid phase transitions in crystalline polymer blends

    NASA Astrophysics Data System (ADS)

    Matkar, Rushikesh A.

    A free energy functional has been formulated based on an order parameter approach to describe the competition between liquid-liquid phase separation and solid-liquid phase separation. In the free energy description, the assumption of complete solvent rejection from the crystalline phase that is inherent in the Flory diluent theory was removed as solvent has been found to reside in the crystalline phase in the form of intercalates. Using this approach, we have calculated various phase diagrams in binary blends of crystalline and amorphous polymers that show upper or lower critical solution temperature. Also, the discrepancy in the chi values obtained from different experimental methods reported in the literature for the polymer blend of poly(vinylidenefluoride) and poly(methylmethacrylate) has been discussed in the context of the present model. Experimental phase diagram for the polymer blend of poly(caprolactone) and polystyrene has also been calculated. Of particular importance is that the crystalline phase concentration as a function of temperature has been calculated using free energy minimization methods instead of assuming it to be pure. In the limit of complete immiscibility of the solvent in the crystalline phase, the Flory diluent theory is recovered. The model is extended to binary crystalline blends and the formation of eutectic, peritectic and azeotrope phase diagrams has been explained on the basis of departure from ideal solid solution behavior. Experimental eutectic phase diagram from literature of a binary blend of crystalline polymer poly(caprolactone) and trioxane were recalculated using the aforementioned approach. Furthermore, simulations on the spatio temporal dynamics of crystallization in blends of crystalline and amorphous polymers were carried out using the Ginzburg-Landau approach. These simulations have provided insight into the distribution of the amorphous polymer in the blends during the crystallization process. The simulated results

  17. Development of novel solid-phase protein formulations

    NASA Astrophysics Data System (ADS)

    Montalvo Ortiz, Brenda Liz

    Proteins are the next-generation drugs for the treatment of several diseases. However, the number of protein drugs is still limited due to the physical or chemical instability of proteins during processing, formulation, storage, and delivery. The formulation of proteins at the solid state has advantages over liquid state, such as improved stability during long-term storage and delivery and decreases transportation costs. In this dissertation, we developed new solid-phase protein formulations in which the integrity of the protein was not compromised. The long term goal of this research was to use these protein formulations to improve protein stability in drug delivery devices, such as poly(lactic-co-glycolic) acid (PLGA). The first solid-phase protein formulation developed in this investigation was named "glassification". We proposed glassification as an alternative protein dehydration technique to the common used one, lyophilization, because this last method involves a series of steps which are detrimental to protein structure and stability. The glassification method consisted on protein dehydration by the use of organic solvents. As a result of the glassification process a small (micrometer size range) protein solid bead was obtained. The proteins used to study the glassification process were lysozyme (LYS), alpha-chymotrypsin (CHYMO) and horseradish peroxidase (HRP). These studies revealed that the glassification process itself did not alter protein structure and the activity was preserved. Ethyl acetate was the most effective organic solvent for protein glassification because it led to the highest protein residual activity, no insoluble aggregate formation and is a relatively non-toxic solvent, which allow the incorporation of these protein microparticles in PLGA microspheres. The incorporation of spherical HRP microparticles into PLGA microspheres resulted in superior properties when compared with encapsulated lyophilized HRP powder, such as improved release

  18. Size Dependence of a Temperature-Induced Solid-Solid Phase Transition in Copper(I) Sulfide

    SciTech Connect

    Rivest, Jessy B; Fong, Lam-Kiu; Jain, Prashant K; Toney, Michael F; Alivisatos, A Paul

    2011-07-24

    Determination of the phase diagrams for the nanocrystalline forms of materials is crucial for our understanding of nanostructures and the design of functional materials using nanoscale building blocks. The ability to study such transformations in nanomaterials with controlled shape offers further insight into transition mechanisms and the influence of particular facets. Here we present an investigation of the size-dependent, temperature-induced solid-solid phase transition in copper sulfide nanorods from low- to high-chalcocite. We find the transition temperature to be substantially reduced, with the high chalcocite phase appearing in the smallest nanocrystals at temperatures so low that they are typical of photovoltaic operation. Size dependence in phase trans- formations suggests the possibility of accessing morphologies that are not found in bulk solids at ambient conditions. These other- wise-inaccessible crystal phases could enable higher-performing materials in a range of applications, including sensing, switching, lighting, and photovoltaics.

  19. Transformation of ferulic acid to vanillin using a fed-batch solid-liquid two-phase partitioning bioreactor.

    PubMed

    Ma, Xiao-kui; Daugulis, Andrew J

    2014-01-01

    Amycolatopsis sp. ATCC 39116 (formerly Streptomyces setonii) has shown promising results in converting ferulic acid (trans-4-hydroxy-3-methoxycinnamic acid; substrate), which can be derived from natural plant wastes, to vanillin (4-hydroxy-3-methoxybenzaldehyde). After exploring the influence of adding vanillin at different times during the growth cycle on cell growth and transformation performance of this strain and demonstrating the inhibitory effect of vanillin, a solid-liquid two-phase partitioning bioreactor (TPPB) system was used as an in situ product removal technique to enhance transformation productivity by this strain. The thermoplastic polymer Hytrel(®) G4078W was found to have superior partitioning capacity for vanillin with a partition coefficient of 12 and a low affinity for the substrate. A 3-L working volume solid-liquid fed-batch TPPB mode, using 300 g Hytrel G4078W as the sequestering phase, produced a final vanillin concentration of 19.5 g/L. The overall productivity of this reactor system was 450 mg/L. h, among the highest reported in literature. Vanillin was easily and quantitatively recovered from the polymers mostly by single stage extraction into methanol or other organic solvents used in food industry, simultaneously regenerating polymer beads for reuse. A polymer-liquid two phase bioreactor was again confirmed to easily outperform single phase systems that feature inhibitory or easily further degraded substrates/products. This enhancement strategy might reasonably be expected in the production of other flavor and fragrance compounds obtained by biotransformations.

  20. Immobilized metal ion affinity partitioning, a method combining metal-protein interaction and partitioning of proteins in aqueous two-phase systems.

    PubMed

    Birkenmeier, G; Vijayalakshmi, M A; Stigbrand, T; Kopperschläger, G

    1991-02-22

    Immobilized metal ions were used for the affinity extraction of proteins in aqueous two-phase systems composed of polyethylene glycol (PEG) and dextran or PEG and salt. Soluble chelating polymers were prepared by covalent attachment of metal-chelating groups to PEG. The effect on the partitioning of proteins of such chelating PEG derivatives coordinated with different metal ions is demonstrated. The proteins studied were alpha 2-macroglobulin, tissue plasminogen activator, superoxide dismutase and monoclonal antibodies. The results indicate that immobilized metal ion affinity partitioning provides excellent potential for the extraction of proteins. PMID:1710621

  1. Phase field modeling of grain growth in porous polycrystalline solids

    NASA Astrophysics Data System (ADS)

    Ahmed, Karim E.

    The concurrent evolution of grain size and porosity in porous polycrystalline solids is a technically important problem. All the physical properties of such materials depend strongly on pore fraction and pore and grain sizes and distributions. Theoretical models for the pore-grain boundary interactions during grain growth usually employ restrictive, unrealistic assumptions on the pore and grain shapes and motions to render the problem tractable. However, these assumptions limit the models to be only of qualitative nature and hence cannot be used for predictions. This has motivated us to develop a novel phase field model to investigate the process of grain growth in porous polycrystalline solids. Based on a dynamical system of coupled Cahn-Hilliard and All en-Cahn equations, the model couples the curvature-driven grain boundary motion and the migration of pores via surface diffusion. As such, the model accounts for all possible interactions between the pore and grain boundary, which highly influence the grain growth kinetics. Through a formal asymptotic analysis, the current work demonstrates that the phase field model recovers the corresponding sharp-interface dynamics of the co-evolution of grain boundaries and pores; this analysis also fixes the model kinetic parameters in terms of real materials properties. The model was used to investigate the effect of porosity on the kinetics of grain growth in UO2 and CeO2 in 2D and 3D. It is shown that the model captures the phenomenon of pore breakaway often observed in experiments. Pores on three- and four- grain junctions were found to transform to edge pores (pores on two-grain junction) before complete separation. The simulations demonstrated that inhomogeneous distribution of pores and pore breakaway lead to abnormal grain growth. The simulations also showed that grain growth kinetics in these materials changes from boundary-controlled to pore-controlled as the amount of porosity increases. The kinetic growth

  2. Multiplexed MALDI-MS arrays for screening of MIP solid phase extraction materials.

    PubMed

    Jagadeesan, Kishore Kumar; Wierzbicka, Celina; Laurell, Thomas; Sellergren, Börje; Shinde, Sudhirkumar; Ekström, Simon

    2016-05-15

    Technology that facilitates rapid investigation of solid phase extraction protocols using very small amounts of sorbent can save both time and money. The microfabricated ISET (Integrated Selective Enrichment Target) interfaced with MALDI mass spectrometry is able to provide an efficient, economic and generic optimization process for SPE sample preparation. The SPE is performed in a rapid and parallel fashion, with a processing time off only 2h per ISET with 96 samples. Each of the 96 wells on the ISET can hold 600nL of SPE sorbent. The ability to work with small amounts of sorbent and samples in the ISET platform provides a big advantage when developing affinity sorbents, such as molecularly imprinted polymers (MIPs). Here it is demonstrated that an amount of 25mg phosphoserine imprinted MIP (pS-MIP) sorbent can allow for analysis of more than 500 ISET nanovials using a multitude of different conditions. In the presented case, the multiplexed experiments allowed for early discovery of unspecific interactions and subsequent minimization of these, resulting in a protocol that provided improved enrichment of phosphopeptides.

  3. Measurement of associations of pharmaceuticals with dissolved humic substances using solid phase extraction.

    PubMed

    Ding, Yunjie; Teppen, Brian J; Boyd, Stephen A; Li, Hui

    2013-04-01

    An innovative method was developed to determine association of carbadox, lincomycin and tetracycline with dissolved humic acids using solid phase extraction (SPE). Dissolved organic matter (DOM) and DOM-bound pharmaceuticals passed through the SPE cartridge while the cartridge retained freely dissolved pharmaceuticals from water. This method was validated by comparison with the results measured using the common equilibrium dialysis technique. For the SPE method pharmaceutical interaction with DOM required ∼30h to approach the equilibration, whereas 50-120h was needed for the equilibrium dialysis technique. The uneven distributions of freely membrane-penetrating pharmaceuticals and protons inside vs. outside of the dialysis cell due to the Donnan effect resulted in overestimates of pharmaceutical affinity with DOM for the equilibrium dialysis method. The SPE technique eliminates the Donnan effect, and demonstrates itself as a more efficient, less laborious and more accurate method. The measured binding coefficients with DOM followed the order of carbadox

  4. Vacuum-assisted headspace solid phase microextraction of polycyclic aromatic hydrocarbons in solid samples.

    PubMed

    Yiantzi, Evangelia; Kalogerakis, Nicolas; Psillakis, Elefteria

    2015-08-26

    For the first time, Vacuum Assisted Headspace Solid Phase Microextraction (Vac-HSSPME) is used for the recovery of polycyclic aromatic hydrocarbons (PAHs) from solid matrices. The procedure was investigated both theoretically and experimentally. According to the theory, reducing the total pressure increases the vapor flux of chemicals at the soil surface, and hence improves HSSPME extraction kinetics. Vac-HSSPME sampling could be further enhanced by adding water as a modifier and creating a slurry mixture. For these soil-water mixtures, reduced pressure conditions may increase the volatilization rates of compounds with a low K(H) present in the aqueous phase of the slurry mixture and result in a faster HSSPME extraction process. Nevertheless, analyte desorption from soil to water may become a rate-limiting step when significant depletion of the aqueous analyte concentration takes place during Vac-HSSPME. Sand samples spiked with PAHs were used as simple solid matrices and the effect of different experimental parameters was investigated (extraction temperature, modifiers and extraction time). Vac-HSSPME sampling of dry spiked sand samples provided the first experimental evidence of the positive combined effect of reduced pressure and temperature on HSSPME. Although adding 2 mL of water as a modifier improved Vac-HSSPME, humidity decreased the amount of naphthalene extracted at equilibrium as well as impaired extraction of all analytes at elevated sampling temperatures. Within short HSSPME sampling times and under mild sampling temperatures, Vac-HSSPME yielded linear calibration curves in the range of 1-400 ng g(-1) and, with the exception of fluorene, regression coefficients were found higher than 0.99. The limits of detection for spiked sand samples ranged from 0.003 to 0.233 ng g(-1) and repeatability from 4.3 to 10 %. Finally, the amount of PAHs extracted from spiked soil samples was smaller compared to spiked sand samples, confirming that soil could bind target

  5. Vacuum-assisted headspace solid phase microextraction of polycyclic aromatic hydrocarbons in solid samples.

    PubMed

    Yiantzi, Evangelia; Kalogerakis, Nicolas; Psillakis, Elefteria

    2015-08-26

    For the first time, Vacuum Assisted Headspace Solid Phase Microextraction (Vac-HSSPME) is used for the recovery of polycyclic aromatic hydrocarbons (PAHs) from solid matrices. The procedure was investigated both theoretically and experimentally. According to the theory, reducing the total pressure increases the vapor flux of chemicals at the soil surface, and hence improves HSSPME extraction kinetics. Vac-HSSPME sampling could be further enhanced by adding water as a modifier and creating a slurry mixture. For these soil-water mixtures, reduced pressure conditions may increase the volatilization rates of compounds with a low K(H) present in the aqueous phase of the slurry mixture and result in a faster HSSPME extraction process. Nevertheless, analyte desorption from soil to water may become a rate-limiting step when significant depletion of the aqueous analyte concentration takes place during Vac-HSSPME. Sand samples spiked with PAHs were used as simple solid matrices and the effect of different experimental parameters was investigated (extraction temperature, modifiers and extraction time). Vac-HSSPME sampling of dry spiked sand samples provided the first experimental evidence of the positive combined effect of reduced pressure and temperature on HSSPME. Although adding 2 mL of water as a modifier improved Vac-HSSPME, humidity decreased the amount of naphthalene extracted at equilibrium as well as impaired extraction of all analytes at elevated sampling temperatures. Within short HSSPME sampling times and under mild sampling temperatures, Vac-HSSPME yielded linear calibration curves in the range of 1-400 ng g(-1) and, with the exception of fluorene, regression coefficients were found higher than 0.99. The limits of detection for spiked sand samples ranged from 0.003 to 0.233 ng g(-1) and repeatability from 4.3 to 10 %. Finally, the amount of PAHs extracted from spiked soil samples was smaller compared to spiked sand samples, confirming that soil could bind target

  6. Modeling the solid-liquid phase transition in saturated triglycerides

    NASA Astrophysics Data System (ADS)

    Pink, David A.; Hanna, Charles B.; Sandt, Christophe; MacDonald, Adam J.; MacEachern, Ronald; Corkery, Robert; Rousseau, Dérick

    2010-02-01

    We investigated theoretically two competing published scenarios for the melting transition of the triglyceride trilaurin (TL): those of (1) Corkery et al. [Langmuir 23, 7241 (2007)], in which the average state of each TL molecule in the liquid phase is a discotic "Y" conformer whose three chains are dynamically twisted, with an average angle of ˜120° between them, and those of (2) Cebula et al. [J. Am. Oil Chem. Soc. 69, 130 (1992)], in which the liquid-state conformation of the TL molecule in the liquid phase is a nematic h∗-conformer whose three chains are in a modified "chair" conformation. We developed two competing models for the two scenarios, in which TL molecules are in a nematic compact-chair (or "h") conformation, with extended, possibly all-trans, chains at low-temperatures, and in either a Y conformation or an h∗ conformation in the liquid state at temperatures higher than the phase-transition temperature, T∗=319 K. We defined an h-Y model as a realization of the proposal of Corkery et al. [Langmuir 23, 7241 (2007)], and explored its predictions by mapping it onto an Ising model in a temperature-dependent field, performing a mean-field approximation, and calculating the transition enthalpy ΔH. We found that the most plausible realization of the h-Y model, as applied to the solid-liquid phase transition in TL, and likely to all saturated triglycerides, gave a value of ΔH in reasonable agreement with the experiment. We then defined an alternative h-h∗ model as a realization of the proposal of Cebula et al. [J. Am. Oil Chem. Soc. 69, 130 (1992)], in which the liquid phase exhibits an average symmetry breaking similar to an h conformation, but with twisted chains, to see whether it could describe the TL phase transition. The h-h∗ model gave a value of ΔH that was too small by a factor of ˜3-4. We also predicted the temperature dependence of the 1132 cm-1 Raman band for both models, and performed measurements of the ratios of three TL Raman

  7. Solid-Phase Synthesis of Oligodeoxynucleotide Analogs Containing Phosphorodithioate Linkages.

    PubMed

    Yang, Xianbin

    2016-01-01

    The oligodeoxynucleotide phosphorodithioate modification (PS2-ODN) uses two sulfur atoms to replace two non-bridging oxygen atoms at an internucleotide phosphordiester backbone linkage. Like a natural phosphodiester ODN backbone linkage, a PS2-modified backbone linkage is achiral at phosphorus. PS2-ODNs are highly stable to nucleases and numerous in vitro assays have demonstrated their biological activity. For example, PS2-ODNs activated RNase H in vitro, strongly inhibited human immunodeficiency virus (HIV) reverse transcriptase, induced B-cell proliferation and differentiation, and bound to protein targets in the form of PS2-aptamers (thioaptamers). Thus, the interest in and promise of PS2-ODNs has spawned a variety of strategies for synthesizing, isolating, and characterizing this compounds. ODN-thiophosphoramidite monomers are commercially available from either AM Biotechnologies or Glen Research and this unit describes an effective methodology for solid-phase synthesis, deprotection, and purification of ODNs having PS2 internucleotide linkages. © 2016 by John Wiley & Sons, Inc. PMID:27584703

  8. Solid-phase synthesis of oxaliplatin-TAT peptide bioconjugates.

    PubMed

    Abramkin, Sergey; Valiahdi, Seied M; Jakupec, Michael A; Galanski, Markus; Metzler-Nolte, Nils; Keppler, Bernhard K

    2012-03-14

    Platinum-based drugs play a crucial role in the fight against cancer. Oxaliplatin, which is used in the treatment of colorectal carcinoma, was the last platinum-based agent to be approved worldwide. However, the efficiency of the therapy is limited for example by a low accumulation of the drug in cancer cells. Cell-penetrating peptides (CPPs) are known to ease the cellular membrane transport and are used as vectors for low-molecular-weight drugs and drug carriers; of them, TAT peptides are the best-studied group. In this work, a TAT-peptide fragment (YGRKKRRQRRR) was for the first time conjugated to a platinum(IV) analog of oxaliplatin as a vehicle for membrane penetration. Solid-phase peptide synthesis and subsequent coupling with the platinum complex afforded mono- and difunctionalized conjugates, which were separated by preparative HPLC and characterized by analytical HPLC, ESI-MS, and (1)H NMR spectroscopy. Both conjugates are active in the low micromolar range in CH1 and SW480 human cancer cells, requiring much lower concentrations than the untargeted analogs for equal effects.

  9. Solid phase microextraction of pesticide residues from strawberries.

    PubMed

    Hu, R; Hennion, B; Urruty, L; Montury, M

    1999-03-01

    A new solid phase microextraction method for the determination of pesticide residues in strawberries for 16 commonly used compounds was described. The strawberries were crushed and centrifuged. An aliquot of the well agitated aqueous supernatant (4 ml) was extracted with a fibre coated with polydimethylsiloxane (PDMS, 100 microns) for 45 min at room temperature. Identification and quantification were achieved using a gas chromatography-mass spectrometry (GC-MS) system and selective ion monitoring (SIM). The method was tested for the following pesticides: carbofuran, diethofencarb, penconazole, hexaconazole, metalaxyl, folpet, bromopropylate, dichlofluanid, alpha-endosulfan, beta-endosulfan, parathion ethyl, procymidone, iprodione, vinclozolin, myclobutanil and chlorothalonil. Limits of detection, repeatability and linearity for standard calibration in strawberries were obtained. Positive and negative effects of the matrix between the extracting solution of strawberries and water were observed. Stabilities of these compounds in the extracting solution of strawberries were determined. The solvent-free SPME procedure was found to be quicker and more cost effective than the solvent extraction methods commonly used.

  10. Solid-phase microextraction and the human fecal VOC metabolome.

    PubMed

    Dixon, Emma; Clubb, Cynthia; Pittman, Sara; Ammann, Larry; Rasheed, Zeehasham; Kazmi, Nazia; Keshavarzian, Ali; Gillevet, Pat; Rangwala, Huzefa; Couch, Robin D

    2011-01-01

    The diagnostic potential and health implications of volatile organic compounds (VOCs) present in human feces has begun to receive considerable attention. Headspace solid-phase microextraction (SPME) has greatly facilitated the isolation and analysis of VOCs from human feces. Pioneering human fecal VOC metabolomic investigations have utilized a single SPME fiber type for analyte extraction and analysis. However, we hypothesized that the multifarious nature of metabolites present in human feces dictates the use of several diverse SPME fiber coatings for more comprehensive metabolomic coverage. We report here an evaluation of eight different commercially available SPME fibers, in combination with both GC-MS and GC-FID, and identify the 50/30 µm CAR-DVB-PDMS, 85 µm CAR-PDMS, 65 µm DVB-PDMS, 7 µm PDMS, and 60 µm PEG SPME fibers as a minimal set of fibers appropriate for human fecal VOC metabolomics, collectively isolating approximately 90% of the total metabolites obtained when using all eight fibers. We also evaluate the effect of extraction duration on metabolite isolation and illustrate that ex vivo enteric microbial fermentation has no effect on metabolite composition during prolonged extractions if the SPME is performed as described herein. PMID:21494609

  11. Solid-Phase Microextraction and the Human Fecal VOC Metabolome

    PubMed Central

    Dixon, Emma; Clubb, Cynthia; Pittman, Sara; Ammann, Larry; Rasheed, Zeehasham; Kazmi, Nazia; Keshavarzian, Ali; Gillevet, Pat; Rangwala, Huzefa; Couch, Robin D.

    2011-01-01

    The diagnostic potential and health implications of volatile organic compounds (VOCs) present in human feces has begun to receive considerable attention. Headspace solid-phase microextraction (SPME) has greatly facilitated the isolation and analysis of VOCs from human feces. Pioneering human fecal VOC metabolomic investigations have utilized a single SPME fiber type for analyte extraction and analysis. However, we hypothesized that the multifarious nature of metabolites present in human feces dictates the use of several diverse SPME fiber coatings for more comprehensive metabolomic coverage. We report here an evaluation of eight different commercially available SPME fibers, in combination with both GC-MS and GC-FID, and identify the 50/30 µm CAR-DVB-PDMS, 85 µm CAR-PDMS, 65 µm DVB-PDMS, 7 µm PDMS, and 60 µm PEG SPME fibers as a minimal set of fibers appropriate for human fecal VOC metabolomics, collectively isolating approximately 90% of the total metabolites obtained when using all eight fibers. We also evaluate the effect of extraction duration on metabolite isolation and illustrate that ex vivo enteric microbial fermentation has no effect on metabolite composition during prolonged extractions if the SPME is performed as described herein. PMID:21494609

  12. Solid Phase Microextraction for the Analysis of Nuclear Weapons

    SciTech Connect

    Chambers, D M

    2001-06-01

    This document is a compendium of answers to commonly asked questions about solid phase microextraction as it relates to the analysis of nuclear weapons. We have also included a glossary of terms associated with this analytical method as well as pertinent weapons engineering terminology. Microextraction is a new collection technique being developed to nonintrusively sample chemicals from weapon headspace gases for subsequent analysis. The chemicals that are being targeted outgas from the high explosives and other organic materials used in the weapon assembly. This technique is therefore a valuable tool to: (1) remotely detect and assess the aging of Lawrence Livermore National Laboratory (LLNL) and, in some cases, Sandia National Laboratory (SNL) organic materials; and (2) identify potential compatibility issues (i.e., materials interactions) that should be more carefully monitored during surveillance tear-downs. Microextraction is particularly attractive because of the practical constraints inherent to the weapon surveillance procedure. To remain transparent to other core surveillance activities and fall within nuclear safety guidelines, headspace analysis of the weapons requires a procedure that: (1) maintains ambient temperature conditions; (2) allows practical collection times of less than 20 min; (3) maintains the integrity of the weapon gas volume; (4) provides reproducible and quantitative results; and (5) can identify all possible targets.

  13. Molecularly imprinted solid phase extraction of fluconazole from pharmaceutical formulations.

    PubMed

    Manzoor, S; Buffon, R; Rossi, A V

    2015-03-01

    This work encompasses a direct and coherent strategy to synthesise a molecularly imprinted polymer (MIP) capable of extracting fluconazole from its sample. The MIP was successfully prepared from methacrylic acid (functional monomer), ethyleneglycoldimethacrylate (crosslinker) and acetonitrile (porogenic solvent) in the presence of fluconazole as the template molecule through a non-covalent approach. The non-imprinted polymer (NIP) was prepared following the same synthetic scheme, but in the absence of the template. The data obtained from scanning electronic microscopy, infrared spectroscopy, thermogravimetric and nitrogen Brunauer-Emmett-Teller plot helped to elucidate the structural as well as the morphological characteristics of the MIP and NIP. The application of MIP as a sorbent was demonstrated by packing it in solid phase extraction cartridges to extract fluconazole from commercial capsule samples through an offline analytical procedure. The quantification of fluconazole was accomplished through UPLC-MS, which resulted in LOD≤1.63×10(-10) mM. Furthermore, a high percentage recovery of 91±10% (n=9) was obtained. The ability of the MIP for selective recognition of fluconazole was evaluated by comparison with the structural analogues, miconazole, tioconazole and secnidazole, resulting in percentage recoveries of 51, 35 and 32%, respectively.

  14. Molecularly imprinted solid phase extraction of fluconazole from pharmaceutical formulations.

    PubMed

    Manzoor, S; Buffon, R; Rossi, A V

    2015-03-01

    This work encompasses a direct and coherent strategy to synthesise a molecularly imprinted polymer (MIP) capable of extracting fluconazole from its sample. The MIP was successfully prepared from methacrylic acid (functional monomer), ethyleneglycoldimethacrylate (crosslinker) and acetonitrile (porogenic solvent) in the presence of fluconazole as the template molecule through a non-covalent approach. The non-imprinted polymer (NIP) was prepared following the same synthetic scheme, but in the absence of the template. The data obtained from scanning electronic microscopy, infrared spectroscopy, thermogravimetric and nitrogen Brunauer-Emmett-Teller plot helped to elucidate the structural as well as the morphological characteristics of the MIP and NIP. The application of MIP as a sorbent was demonstrated by packing it in solid phase extraction cartridges to extract fluconazole from commercial capsule samples through an offline analytical procedure. The quantification of fluconazole was accomplished through UPLC-MS, which resulted in LOD≤1.63×10(-10) mM. Furthermore, a high percentage recovery of 91±10% (n=9) was obtained. The ability of the MIP for selective recognition of fluconazole was evaluated by comparison with the structural analogues, miconazole, tioconazole and secnidazole, resulting in percentage recoveries of 51, 35 and 32%, respectively. PMID:25618633

  15. Determining the solid phases hosting arsenic in Mekong Delta sediments

    NASA Astrophysics Data System (ADS)

    Wucher, M.; Stuckey, J. W.; McCurdy, S.; Fendorf, S.

    2011-12-01

    The major river systems originating from the Himalaya deposit arsenic bearing sediment into the deltas of South and Southeast Asia. High rates of sediment and organic carbon deposition combined with frequent flooding leads to anaerobic processes that release arsenic into the pore-water. Arsenic concentrations in the groundwater of these sedimentary basins are often above the World Health Organization drinking water standard of 10 μg As L-1. As a result, 150 million people are at risk of chronic arsenic poisoning through water and rice consumption. The composition of the iron bearing phases hosting the arsenic in these deltaic sediments is poorly understood. Here we implemented a suite of selective chemical extractions to help constrain the types of arsenic bearing solid phases, which were complimented with synchrotron-based X-ray absorption spectroscopy and X-ray diffraction analyses to define the arsenic and iron mineralogy of the system. Sediment cores were collected in triplicate from a seasonally-inundated wetland in Cambodia at depths of 10, 50, 100, and 150 centimeters. We hypothesize that (i) arsenic will be predominantly associated with iron oxides, and (ii) the ratio of crystalline to amorphous iron oxides will increase with sediment depth (and age). We performed four selective extractions in parallel to quantify the various pools of arsenic. First, 1 M MgCl2 was used to extract electrostatically-bound arsenic (labile forms) from the sediment. Second, 1 M NaH2PO4 targeted strongly adsorbed arsenic. Third, 1 M HCl was used to liberated arsenic coprecipitated with amorphous Fe/Mn oxides, carbonates, and acid-volatile sulfides. Finally, a dithionite extraction was used to account for arsenic associated with reducible Fe/Mn oxides. Through this work, we identified the composition of the phases hosting arsenic at various depths through the soil profile, improving our understanding of how arsenic persists in the aquifer. In addition, defining the arsenic and

  16. The Iron-Iron Carbide Phase Diagram: A Practical Guide to Some Descriptive Solid State Chemistry.

    ERIC Educational Resources Information Center

    Long, Gary J.; Leighly, H. P., Jr.

    1982-01-01

    Discusses the solid state chemistry of iron and steel in terms of the iron-iron carbide phase diagram. Suggests that this is an excellent way of introducing the phase diagram (equilibrium diagram) to undergraduate students while at the same time introducing the descriptive solid state chemistry of iron and steel. (Author/JN)

  17. Manual Solid-Phase Peptide Synthesis of Metallocene-Peptide Bioconjugates

    ERIC Educational Resources Information Center

    Kirin, Srecko I.; Noor, Fozia; Metzler-Nolte, Nils; Mier, Walter

    2007-01-01

    A simple and relatively inexpensive procedure for preparing a biologically active peptide using solid phase peptide synthesis (SPPS) is described. Fourth-year undergraduate students have gained firsthand experience from the solid-phase synthesis techniques and they have become familiar with modern analytical techniques based on the particular…

  18. Estimating production and consumption of solid reactive Fe phases in marine sediments from concentration profiles

    EPA Science Inventory

    1D diffusion models may be used to estimate rates of production and consumption of dissolved metabolites in marine sediments, but are applied less often to the solid phase. Here we used a numerical inverse method to estimate solid phase Fe(III) and Fe(II) consumption and product...

  19. Influence of solid polymers on the response of multi-phase bioreactors treating α-pinene-polluted air.

    PubMed

    Montes, María; Veiga, María C; Kennes, Christian

    2014-09-25

    The use of biological techniques for the removal of hydrophobic and recalcitrant volatile compounds at industrial scale has recently significantly increased. In the present work, studies were undertaken aimed at comparing the performance of a continuous stirred tank bioreactor (CSTB) with either a single liquid phase or in the presence of a solid non-aqueous phase (NAP), for the biodegradation of α-pinene. Specifically, 3.5mm diameter beads of Hytrel G3548L were selected as solid NAP based on their affinity for α-pinene. Performance was evaluated over a period of 322 days. However, the experimental results showed no significant enhancement of α-pinene biodegradation in presence of the NAP compared to the reactor with a single liquid phase. Under steady-state conditions, when Hytrel G3548L (5%) was added to the CSTB, the maximum elimination capacity (ECmax) achieved was ∼60 g m(-3)h(-1), which was similar as in the absence of the NAP. Under transient shock-load conditions similar results were obtained with or without NAP, although attenuation was observed in the decrease of the removal efficiency (RE) during overload when polymer beads were present.

  20. Novel materials and methods for solid-phase extraction and liquid chromatography

    SciTech Connect

    Ambrose, D.

    1997-06-24

    This report contains a general introduction which discusses solid-phase extraction and solid-phase micro-extraction as sample preparation techniques for high-performance liquid chromatography, which is also evaluated in the study. This report also contains the Conclusions section. Four sections have been removed and processed separately: silicalite as a sorbent for solid-phase extraction; a new, high-capacity carboxylic acid functionalized resin for solid-phase extraction; semi-micro solid-phase extraction of organic compounds from aqueous and biological samples; and the high-performance liquid chromatographic determination of drugs and metabolites in human serum and urine using direct injection and a unique molecular sieve.

  1. Use of Solid-Phase Extraction To Determine Ergosterol Concentrations in Plant Tissue Colonized by Fungi

    PubMed Central

    Gessner, M. O.; Schmitt, A. L.

    1996-01-01

    At present, the ergosterol and acetate-to-ergosterol techniques are generally considered to be the methods of choice to quantify fungal biomass, growth rate, and productivity under natural conditions. Both methods rely on the accurate isolation and quantification of ergosterol, a major membrane component of eumycotic fungi. Taking advantage of the solid-phase extraction (SPE) technique, we present a novel method to determine the ergosterol concentration in lipid extracts derived from plant tissues and dead organic matter colonized by fungi. In this method, a primary alkaline extract is acidified and passed through a reversed-phase (C(inf18)) SPE column. The column is then washed with an alkaline methanol-water solution to eliminate interfering substances and increase pH and is thoroughly dried in air. Ergosterol is eluted with alkaline isopropanol. This eluting solvent was chosen to produce a strongly basic pH of the final extract and thus confer stability on the ergosterol molecule before high-performance liquid chromatography analysis. The recovery of ergosterol from plant tissues and the O(infhf) horizon of a woodland soil ranged from 85 to 98%, and the overall extraction efficiency was similar to that obtained by a conventional procedure involving liquid-liquid extraction. Potential pitfalls of ergosterol analysis by SPE include (i) insufficient acidification before sample loading on the extraction column, resulting in a poor affinity of ergosterol for the sorbent; (ii) incomplete drying of the sorbent bed before the elution step; and (iii) chemical breakdown of ergosterol after elution, which was found to be related to a low pH of the final extract and a high concentration of matrix compounds. When these pitfalls are avoided, SPE is an attractive alternative to existing methods of ergosterol analysis of environmental samples. PMID:16535229

  2. Affinity Chromatography.

    ERIC Educational Resources Information Center

    Gray, Gary R.

    1980-01-01

    Presents selected recent advances in immobilization chemistry which have important connections to affinity chromatography. Discusses ligand immobilization and support modification. Cites 51 references. (CS)

  3. Porous, High Capacity Coatings for Solid Phase Microextraction by Sputtering.

    PubMed

    Diwan, Anubhav; Singh, Bhupinder; Roychowdhury, Tuhin; Yan, DanDan; Tedone, Laura; Nesterenko, Pavel N; Paull, Brett; Sevy, Eric T; Shellie, Robert A; Kaykhaii, Massoud; Linford, Matthew R

    2016-02-01

    We describe a new process for preparing porous solid phase microextraction (SPME) coatings by the sputtering of silicon onto silica fibers. The microstructure of these coatings is a function of the substrate geometry and mean free path of the silicon atoms, and the coating thickness is controlled by the sputtering time. Sputtered silicon structures on silica fibers were treated with piranha solution (a mixture of concd H2SO4 and 30% H2O2) to increase the concentration of silanol groups on their surfaces, and the nanostructures were silanized with octadecyldimethylmethoxysilane in the gas phase. The attachment of this hydrophobic ligand was confirmed by X-ray photoelectron spectroscopy and contact angle goniometry on model, planar silicon substrates. Sputtered silicon coatings adhered strongly to their surfaces, as they were able to pass the Scotch tape adhesion test. The extraction time and temperature for headspace extraction of mixtures of alkanes and alcohols on the sputtered fibers were optimized (5 min and 40 °C), and the extraction performances of SPME fibers with 1.0 or 2.0 μm of sputtered silicon were compared to those from a commercial 7 μm poly(dimethylsiloxane) (PDMS) fiber. For mixtures of alcohols, aldehydes, amines, and esters, the 2.0 μm sputtered silicon fiber yielded signals that were 3-9, 3-5, 2.5-4.5, and 1.5-2 times higher, respectively, than those of the commercial fiber. For the heavier alkanes (undecane-hexadecane), the 2.0 μm sputtered fiber yielded signals that were approximately 1.0-1.5 times higher than the commercial fiber. The sputtered fibers extracted low molecular weight analytes that were not detectable with the commercial fiber. The selectivity of the sputtered fibers appears to favor analytes that have both a hydrophobic component and hydrogen-bonding capabilities. No detectable carryover between runs was noted for the sputtered fibers. The repeatability (RSD%) for a fiber (n = 3) was less than 10% for all analytes tested

  4. Solid rocket motor fire tests: Phases 1 and 2

    NASA Astrophysics Data System (ADS)

    Chang, Yale; Hunter, Lawrence W.; Han, David K.; Thomas, Michael E.; Cain, Russell P.; Lennon, Andrew M.

    2002-01-01

    JHU/APL conducted a series of open-air burns of small blocks (3 to 10 kg) of solid rocket motor (SRM) propellant at the Thiokol Elkton MD facility to elucidate the thermal environment under burning propellant. The propellant was TP-H-3340A for the STAR 48 motor, with a weight ratio of 71/18/11 for the ammonium perchlorate, aluminum, and HTPB binder. Combustion inhibitor applied on the blocks allowed burning on the bottom and/or sides only. Burns were conducted on sand and concrete to simulate near-launch pad surfaces, and on graphite to simulate a low-recession surface. Unique test fixturing allowed propellant self-levitation while constraining lateral motion. Optics instrumentation consisted of a longwave infrared imaging pyrometer, a midwave spectroradiometer, and a UV/visible spectroradiometer. In-situ instrumentation consisted of rod calorimeters, Gardon gauges, elevated thermocouples, flush thermocouples, a two-color pyrometer, and Knudsen cells. Witness materials consisted of yttria, ceria, alumina, tungsten, iridium, and platinum/rhodium. Objectives of the tests were to determine propellant burn characteristics such as burn rate and self-levitation, to determine heat fluxes and temperatures, and to carry out materials analyses. A summary of qualitative results: alumina coated almost all surfaces, the concrete spalled, sand moisture content matters, the propellant self-levitated, the test fixtures worked as designed, and bottom-burning propellant does not self-extinguish. A summary of quantitative results: burn rate averaged 1.15 mm/s, thermocouples peaked at 2070 C, pyrometer readings matched MWIR data at about 2400 C, the volume-averaged plume temperatures were 2300-2400 C with peaks of 2400-2600 C, and the heat fluxes peaked at 125 W/cm2. These results are higher than other researchers' measurements of top-burning propellant in chimneys, and will be used, along with Phase 3 test results, to analyze hardware response to these environments, including General

  5. Versatile Solid Phase Syntheses of Structured Nanoparticle Hybrids

    NASA Astrophysics Data System (ADS)

    Koberstein, Jeffrey

    2011-03-01

    While it is widely recognized that nanoparticles can exhibit a wide variety of exciting size-dependent properties and responses, it is equally important to recognize that devices and systems cannot be created from bare nanoparticles alone. The potential of nanoparticles can only be achieved by proper consideration of matrices that not only provide mechanical support and integrity to the nanoparticles, but can also control various aspects of their spatial assembly such as geometry and interparticle spacing. Polymers represent a logical and robust matrix for the creation of nanocomposite assemblies, however, phenomena such as aggregation are often problematic when blending nanoparticles and homopolymers. These problems can be avoided by preparation of nanoparticle hybrids wherein all required polymers are covalently tethered to the nanoparticles prior to assembly so that a polymer matrix is not necessary. We report on a new method for covalent decoration of nanoparticles with polymers of tailored molecular design that is based upon a solid phase synthesis strategy. The modular process, much like molecular Tinker Toys, is capable of decorating nanoparticles with essentially any type of branched or copolymeric structure using only a few elementary heterobifunctional building blocks. Because end group functionality is always retained in the process, functional nanoparticles can be readily crosslinked by simple orthogonal reactions such as azide-alkyne click chemistry. The method can be used to create sophisticated hybrid nanoparticle structures important to drug delivery applications, to form highly functional crosslinkers that gel at conversions as low as a few percent, or to fabricate crosslinked matrix-free nanocomposites. Supported by grants DMR-0704054 from the NSF and W911NF-10-1-0184 from the US Army Research Office.

  6. Solid-phase synthesis of peptide-4-nitroanilides.

    PubMed

    Kaspari, A; Schierhorn, A; Schutkowski, M

    1996-11-01

    A wide variety of Glu/Asp and Gln containing peptide-4-nitroanilides and other chromogenic peptidyl-arylamides could be quickly synthesized by a Fmoc-based solid-phase synthesis strategy employing the side-chain carboxyl groups for transient anchoring to the resin. Suitable synthons for this method, Fmoc-Glu-NH-Np and Fmoc-Asp-NH-Np, were prepared using a diphenylphosphinic chloride-mediated coupling reaction. Peptides of the common structure Suc-Ala-Phe-Pro-Xaa-NH-Np (Xaa = Glu/Asp, Gln) were synthesized and were shown to be substrates for the protease subtilisin Carlsberg (E.C.3.4.21.14a) and for peptidyl-prolyl cis/trans-isomerases (PPIases E.C. 5.2.1.8.). The method was extended to amino acids possessing a side chain missing an anchor for binding to the matrix. We synthesized Suc-Ala-Phe-Pro-Gln-Phe-NH-Np anchoring the dipeptide derivative Fmoc-Glu-Phe-NH-Np with the carboxyl group to Rink amide resin using standard SPPS procedures. Additionally this procedure allowed us the preparation of peptidyl-arylamides, utilizing the commercial available Fmoc-Glu-OAll as building block. A mixture of pentapeptide-4-nitroanilides with the general sequence Ala-Ala-Xaa-Pro-Gln-NH-Np was synthesized. Electrospray ionization mass spectrometry (ESI-MS) was used to evaluate the hydrolysis of the peptide mixture by the protease subtilisin Carlsberg. It could be shown that peptides with the hydrophobic amino acids Phe, Tyr, Leu and Val in the varied P3-position were most rapidly cleaved under the chosen conditions. Hydrolysis of the Gln-NH-Np bond in Ala-Ala-Pro-Pro-Gln-NH-Np has not been observed.

  7. Application of solid phase microextraction on dental composite resin analysis.

    PubMed

    Wang, Ven-Shing; Chang, Ta-Yuan; Lai, Chien-Chen; Chen, San-Yue; Huang, Long-Chen; Chao, Keh-Ping

    2012-08-15

    A direct immersion solid phase microextraction (DI-SPME) method was developed for the analysis of dentin monomers in saliva. Dentine monomers, such as triethylene glycol dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA) and 2,2-bis-[4-(2-hydroxy-3-methacryloyloxypropoxy) phenyl]-propane (Bis-GMA), have a high molecular weight and a low vapor pressure. The polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber with a medium polarity was employed for DI-SPME, and 215 nm of detection wavelength was found to be optimum in the chromatogram of HPLC measurement. The calibration range for DI-SPME was 0.30-300 μg/mL with correlation coefficients (r) greater than 0.998 for each analyte. The DI-SPME method achieved good accuracy (recovery 96.1-101.2%) and precision (2.30-8.15% CV) for both intra- and inter-day assays of quality control samples for three target compounds. Method validation was performed on standards dissolved in blank saliva, and there was no significant difference (p>0.2) between the DI-SPME method and the liquid injection method. However, the detection limit of DI-SPME was as low as 0.03, 0.27 and 0.06 μg/mL for TEGDMA, UDMA and Bis-GMA, respectively. Real sample analyses were performed on commercial dentin products after curing for the leaching measurement. In summary, DI-SPME is a more sensitive method that requires less sample pretreatment procedures to measure the resin materials leached in saliva.

  8. Use of continuous solid-phase synthesis to obtain phosphors based on strontium aluminate

    NASA Astrophysics Data System (ADS)

    Kerbel, B.; Katsnelson, L.; Falkovich, Yu; Prokopyev, D.

    2016-02-01

    The effect of conditions of continuous solid-phase synthesis on particle size distribution of nanostructured powders of strontium aluminate was studied. It was shown that continuous solid-phase synthesis allows for: synthesis of strontium aluminate in the form of nanostructured powders with controlled particle size distribution directly during its synthesis; in the presence of a liquid phase strontium aluminate is synthesized with a high level of monophasity. It was shown that in order to optimize the illuminating parameters of phosphors based on strontium aluminate, it is advisable to use continuous solid-phase synthesis.

  9. Reconstruction of Porous Media with Multiple Solid Phases

    PubMed

    Losic; Thovert; Adler

    1997-02-15

    A process is proposed to generate three-dimensional multiphase porous media with fixed phase probabilities and an overall correlation function. By varying the parameters, a specific phase can be located either at the interface between two phases or within a single phase. When the interfacial phase has a relatively small probability, its shape can be chosen as granular or lamellar. The influence of a third phase on the macroscopic conductivity of a medium is illustrated. PMID:9056372

  10. Solid-phase radioimmunoassay for human neutrophil elastase: a sensitive method for determining secreted and cell-associated enzyme

    SciTech Connect

    Dunn, T.L.; Blackburn, W.D.; Koopman, W.J.; Heck, L.W.

    1985-10-01

    A solid-phase radioimmunoassay for measuring neutrophil elastase in the range 0.08-4 ng/ml has been developed. A monospecific, precipitating antibody capable of inhibiting elastinolysis was produced by repeated immunizations of a goat. The IgG fraction and affinity-purified antibodies of this serum were then obtained and used to develop this radioimmunoassay. There was no cross-reactivity in binding of the radiolabeled antisera with lactoferrin, cathepsin G, or serine proteinases with amino-terminal amino acid sequence homology. Although serum influences the measurement of catalytically active neutrophil elastase when compared to diisopropylfluorophosphate-treated neutrophil elastase, antigenic elastase may still be measured in body fluids. Furthermore, this assay is more sensitive than commercially available substrates used for quantitating neutrophil elastase by functional activity. We have found this quantitative assay extremely useful in balance studies to measure secreted and cell-associated elastase and in screening of biological fluids for the presence of the enzyme.

  11. Solid-phase extraction based on ground methacrylate monolith modified with gold nanoparticles for isolation of proteins.

    PubMed

    Vergara-Barberán, María; Lerma-García, María Jesús; Simó-Alfonso, Ernesto Francisco; Herrero-Martínez, José Manuel

    2016-04-21

    In this study, a novel polymeric material functionalized with gold nanoparticles (AuNPs) was prepared as solid-phase extraction (SPE) sorbent for isolation of proteins. The sorbent was synthesized from a powdered poly(glycidyl-co-ethylene dimethacrylate) monolith, and modified with ammonia, followed by immobilization of AuNPs on the pore surface of the material. To evaluate the performance of this SPE support, proteins were selected as test solutes, being the extraction conditions and other parameters (loading capacity and regenerative ability of sorbent) established. The results indicated that this sorbent could be employed to selectively capture proteins according to their pI, on the basis of the strong affinity of these biomacromolecules towards to AuNPs surface. The applicability of this sorbent was demonstrated by isolating protein species of interest (bovine serum albumin, cytochrome c and lectins in European mistletoe leaves), followed by SDS-PAGE analysis. PMID:27026598

  12. Solid-Phase Extraction Strategies to Surmount Body Fluid Sample Complexity in High-Throughput Mass Spectrometry-Based Proteomics

    PubMed Central

    Bladergroen, Marco R.; van der Burgt, Yuri E. M.

    2015-01-01

    For large-scale and standardized applications in mass spectrometry- (MS-) based proteomics automation of each step is essential. Here we present high-throughput sample preparation solutions for balancing the speed of current MS-acquisitions and the time needed for analytical workup of body fluids. The discussed workflows reduce body fluid sample complexity and apply for both bottom-up proteomics experiments and top-down protein characterization approaches. Various sample preparation methods that involve solid-phase extraction (SPE) including affinity enrichment strategies have been automated. Obtained peptide and protein fractions can be mass analyzed by direct infusion into an electrospray ionization (ESI) source or by means of matrix-assisted laser desorption ionization (MALDI) without further need of time-consuming liquid chromatography (LC) separations. PMID:25692071

  13. Solid-phase extraction based on ground methacrylate monolith modified with gold nanoparticles for isolation of proteins.

    PubMed

    Vergara-Barberán, María; Lerma-García, María Jesús; Simó-Alfonso, Ernesto Francisco; Herrero-Martínez, José Manuel

    2016-04-21

    In this study, a novel polymeric material functionalized with gold nanoparticles (AuNPs) was prepared as solid-phase extraction (SPE) sorbent for isolation of proteins. The sorbent was synthesized from a powdered poly(glycidyl-co-ethylene dimethacrylate) monolith, and modified with ammonia, followed by immobilization of AuNPs on the pore surface of the material. To evaluate the performance of this SPE support, proteins were selected as test solutes, being the extraction conditions and other parameters (loading capacity and regenerative ability of sorbent) established. The results indicated that this sorbent could be employed to selectively capture proteins according to their pI, on the basis of the strong affinity of these biomacromolecules towards to AuNPs surface. The applicability of this sorbent was demonstrated by isolating protein species of interest (bovine serum albumin, cytochrome c and lectins in European mistletoe leaves), followed by SDS-PAGE analysis.

  14. Solid-phase extraction strategies to surmount body fluid sample complexity in high-throughput mass spectrometry-based proteomics.

    PubMed

    Bladergroen, Marco R; van der Burgt, Yuri E M

    2015-01-01

    For large-scale and standardized applications in mass spectrometry- (MS-) based proteomics automation of each step is essential. Here we present high-throughput sample preparation solutions for balancing the speed of current MS-acquisitions and the time needed for analytical workup of body fluids. The discussed workflows reduce body fluid sample complexity and apply for both bottom-up proteomics experiments and top-down protein characterization approaches. Various sample preparation methods that involve solid-phase extraction (SPE) including affinity enrichment strategies have been automated. Obtained peptide and protein fractions can be mass analyzed by direct infusion into an electrospray ionization (ESI) source or by means of matrix-assisted laser desorption ionization (MALDI) without further need of time-consuming liquid chromatography (LC) separations. PMID:25692071

  15. The IgG detected in the C1q solid-phase immune-complex assay is not always of immune-complex nature.

    PubMed

    Hack, C E; Belmer, A J

    1986-01-01

    The properties of the solid-phase C1q immune-complex assay as well as the nature of the IgG detected by this assay in patients' sera were investigated. Aggregated IgG was used as a model for immune complexes. Aggregated IgG bound to solid-phase C1q was detected by 125I-anti-IgG. Fluid-phase C1q (either in normal human serum or purified) neither inhibited the binding of aggregated IgG to solid-phase C1q nor dissociated bound aggregated IgG from the solid-phase C1q. Therefore, we concluded that the solid-phase C1q has a higher affinity for aggregated IgG than the fluid-phase C1q, probably because of the polymerization of the solid-phase C1q. To get more insight into the nature of the IgG detected by the C1q solid-phase assay in patients' sera, we investigated whether C4 and/or C3 were present on it. With the use of 125I-anti-C4 and 125I-anti-C3 instead of 125I-anti-IgG, C4 and C3, respectively, were easily detected on the aggregated IgG that had bound to the solid-phase C1q. The lower limit of detection of these assays was 30 micrograms aggregated IgG/ml of normal human serum. Sera of patients suffering from rheumatoid arthritis and systemic lupus erythematosus were tested with these assays and, despite positive results with 125I-anti-IgG, no positive results were obtained with either 125I-anti-C4 or 125I-anti-C3. So, on the IgG detected by the C1q solid-phase assay in patients' sera, neither C4 nor C3 are present. Furthermore, in five of the six sera tested, this IgG sedimented as monomeric IgG. Therefore, it seems unjustified to refer to this IgG as circulating immune complexes.

  16. Phase interface effects in the total enthalpy-based lattice Boltzmann model for solid-liquid phase change

    NASA Astrophysics Data System (ADS)

    Huang, Rongzong; Wu, Huiying

    2015-08-01

    In this paper, phase interface effects, including the differences in thermophysical properties between solid and liquid phases and the numerical diffusion across phase interface, are investigated for the recently developed total enthalpy-based lattice Boltzmann model for solid-liquid phase change, which has high computational efficiency by avoiding iteration procedure and linear equation system solving. For the differences in thermophysical properties (thermal conductivity and specific heat) between solid and liquid phases, a novel reference specific heat is introduced to improve the total enthalpy-based lattice Boltzmann model, which makes the thermal conductivity and specific heat decoupled. Therefore, the differences in thermal conductivity and specific heat can be handled by the dimensionless relaxation time and equilibrium distribution function, respectively. As for the numerical diffusion across phase interface, it is revealed for the first time and found to be induced by solid-liquid phase change. To reduce such numerical diffusion, multiple-relaxation-time collision scheme is exploited, and a special value (one fourth) for the so-called "magic" parameter, a combination of two relaxation parameters, is found. Numerical tests show that the differences in thermophysical properties can be correctly handled and the numerical diffusion across phase interface can be dramatically reduced. Finally, theoretical analyses are carried out to offer insights into the roles of the reference specific heat and "magic" parameter in the treatments of phase interface effects.

  17. Microwave spectroscopic observation of distinct electron solid phases in wide quantum wells.

    PubMed

    Hatke, A T; Liu, Yang; Magill, B A; Moon, B H; Engel, L W; Shayegan, M; Pfeiffer, L N; West, K W; Baldwin, K W

    2014-06-20

    In high magnetic fields, two-dimensional electron systems can form a number of phases in which interelectron repulsion plays the central role, since the kinetic energy is frozen out by Landau quantization. These phases include the well-known liquids of the fractional quantum Hall effect, as well as solid phases with broken spatial symmetry and crystalline order. Solids can occur at the low Landau-filling termination of the fractional quantum Hall effect series but also within integer quantum Hall effects. Here we present microwave spectroscopy studies of wide quantum wells that clearly reveal two distinct solid phases, hidden within what in d.c. transport would be the zero diagonal conductivity of an integer quantum-Hall-effect state. Explanation of these solids is not possible with the simple picture of a Wigner solid of ordinary (quasi) electrons or holes.

  18. Microwave spectroscopic observation of distinct electron solid phases in wide quantum wells

    PubMed Central

    Hatke, A. T.; Liu, Yang; Magill, B. A.; Moon, B. H.; Engel, L. W.; Shayegan, M.; Pfeiffer, L. N.; West, K. W.; Baldwin, K. W.

    2014-01-01

    In high magnetic fields, two-dimensional electron systems can form a number of phases in which interelectron repulsion plays the central role, since the kinetic energy is frozen out by Landau quantization. These phases include the well-known liquids of the fractional quantum Hall effect, as well as solid phases with broken spatial symmetry and crystalline order. Solids can occur at the low Landau-filling termination of the fractional quantum Hall effect series but also within integer quantum Hall effects. Here we present microwave spectroscopy studies of wide quantum wells that clearly reveal two distinct solid phases, hidden within what in d.c. transport would be the zero diagonal conductivity of an integer quantum-Hall-effect state. Explanation of these solids is not possible with the simple picture of a Wigner solid of ordinary (quasi) electrons or holes. PMID:24948190

  19. Materials research for passive solar systems: solid-state phase-change materials

    SciTech Connect

    Benson, D.K.; Webb, J.D.; Burrows, R.W.; McFadden, J.D.O.; Christensen, C.

    1985-03-01

    A set of solid-state phase-change materials is being evaluated for possible use in passive solar thermal energy storage systems. The most promising materials are organic solid solutions of pentaerythritol (C/sub 5/H/sub 12/O/sub 4/), pentaglycerinve (C/sub 5/H/sub 12/O/sub 3/), and neopentyl glycol (C/sub 5/H/sub 12/O/sub 2/). Solid solution mixtures of these compounds can be tailored so that they exhibit solid-to-solid phase transformations at any desired temperature betweeen 25/sup 0/C and 188/sup 0/C, and have latent heats of transformation between 20 and 70 cal/g. Transformation temperatures, specific heats, and latent heats of transformation have been measured for a number of these materials. Limited cyclic experiments suggest that the solid solutions are stable. These phase-change materials exhibit large amounts of undercooling; however, the addition of certain nucleating agents as particulate dispersions in the solid phase-change material greatly reduces this effect. Computer simulations suggest that the use of an optimized solid-state phase-change material in a Trombe wall could provide better performance than a concrete Trombe wall four times thicker and nine times heavier. Nevertheless, a higher cost of the phase-change materials (approx. =$0.70 per pound) is likely to limit their applicability in passive solar systems unless their performance can be significantly improved through further research.

  20. Proposed method for controlling turbid particles in solid-phase bioluminescent toxicity measurement.

    PubMed

    Yeo, Seul-Ki; Park, Jun-Boum; Ahn, Joo-Sung; Han, Young-Soo

    2015-06-01

    In the recent half century, numerous methods have been developed to assess ecological toxicity. However, the presence of solid-particle turbidity sometimes causes such tests to end with questionable results. Many researchers focused on controlling this arbitrary turbidity effect when using the Microtox® solid-phase toxicity system, but there is not yet a standard method. In this study, we examined four solid-phase sample test methods recommended in the Microtox® manual, or proposed from the literature, and compared the existing methods with our proposed method (centrifuged basic solid-phase test, c-BSPT). Four existing methods use the following strategies to control turbid particles: complete separation of liquid and solid using 0.45-μm filtration before contacting solid samples and bacteria, natural settlement, moderate separation of large particles using coarser pore size filtration, and exclusion of light loss in the toxicity calculation caused by turbidity after full disturbance of samples. Our proposed method uses moderate centrifugation to separate out the heavier soil particles from the lighter bacteria after direct contact between them. Among the solid-phase methods tested, in which the bacteria and solid particles were in direct contact (i.e., the three existing methods and the newly proposed one, c-BSPT), no single method could be recommended as optimal for samples over a range of turbidity. Instead, a simple screening strategy for selecting a sample-dependent solid-phase test method was suggested, depending on the turbidity of the solid suspension. The results of this study highlight the importance of considering solid particles, and the necessity for optimal selection of test method to reduce errors in the measurement of solid-phase toxicity.

  1. Hydrofluoric acid etched stainless steel wire for solid-phase microextraction.

    PubMed

    Xu, Hua-Ling; Li, Yan; Jiang, Dong-Qing; Yan, Xiu-Ping

    2009-06-15

    Stainless steel wire has been widely used as the substrate of solid-phase microextraction (SPME) fibers to overcome the shortcomings of conventional silica fibers such as fragility, by many researchers. However, in previous reports various sorbent coatings are always required in conjunction with the stainless steel wire for SPME. In this work, we report the bare stainless steel wire for SPME without the need for any additional coatings taking advantage of its high mechanical and thermal stability. To evaluate the performance of stainless steel wire for SPME, polycyclic aromatic hydrocarbons (PAHs), benzene, toluene, ethylbenzene, chlorobenzene, n-propylbenzene, aniline, phenol, n-hexane, n-octane, n-decane, n-undecane, n-dodecane, chloroform, trichloroethylene, n-octanol, and butanol were tested as analytes. Although the stainless steel wire had almost no extraction capability toward the tested analytes before etching, it did exhibit high affinity to the tested PAHs after etching with hydrofluoric acid. The etched stainless steel wire gave a much bigger enhancement factor (2541-3981) for the PAHs than the other analytes studied (< or = 515). Etching with hydrofluoric acid produced a porous and flower-like structure with Fe(2)O(3), FeF(3), Cr(2)O(3), and CrF(2) on the surface of the stainless steel wire, giving high affinity to the PAHs due to cation-pi interaction. On the basis of the high selectivity of the etched stainless steel wire for PAHs, a new SPME method was developed for gas chromatography with flame ionization detection to determine PAHs with the detection limits of 0.24-0.63 microg L(-1). The precision for six replicate extractions using one SPME fiber ranged from 2.9% to 5.3%. The fiber-to-fiber reproducibility for three parallel prepared fibers was 4.3-8.8%. One etched stainless steel wire can stand over 250 cycles of SPME without significant loss of extraction efficiency. The developed etched stainless steel wire is very stable, highly selective, and

  2. Nano-structured lead dioxide as a novel stationary phase for solid-phase microextraction.

    PubMed

    Mehdinia, Ali; Mousavi, Mir Fazllolah; Shamsipur, Mojtaba

    2006-11-17

    The first study on the high efficiency of nano-structured lead dioxide as a new fiber for solid-phase microextraction (SPME) purposes has been reported. The size of the PbO2 particles was in the range of 34-136 nm. Lead dioxide-based fibers were prepared via electrochemical deposition on a platinum wire. The extraction properties of the fiber to benzene, toluene, ethylbenzene, and xylenes (BTEX) were examined using headspace solid-phase microextraction (HS-SPME) mode coupled to gas chromatography-flame ionization detection (GC-FID). The results obtained proved the suitability of proposed fibers for the sampling of organic compounds from water. The extraction procedure was optimized by selecting the appropriate extraction parameters, including preparation conditions of coating, salt concentration, time and temperature of adsorption and desorption and stirring rate. The calibration graphs were linear in a concentration range of 0.1-100 microg l(-1) (R2 > 0.994) with detection limits below 0.012 microg l(-1) level. Single fiber repeatability and fiber-to-fiber reproducibility were less than 10.0 and 12.5%, respectively. The PbO2 coating was proved to be very stable at relatively high temperatures (up to 300 degrees C) with a high extraction capacity and long lifespan (more than 50 times). Higher chemical resistance and lower cost are among the advantages of PbO2 fibers over commercially available SPME fibers. Good recoveries (81-108%) were obtained when environmental samples were analyzed.

  3. Phase transitions in Kr -CH4 solid solutions and rotational excitations in phase II

    NASA Astrophysics Data System (ADS)

    Bagatskii, M. I.; Mashchenko, D. A.; Dudkin, V. V.

    2007-06-01

    The heat capacity CP of Kr-nCH4 solid solutions with CH4 concentrations n =0.82, 0.86, and 0.90 and of solutions with n =0.90, 0.95 doped with 0.002 O2 impurity is investigated under equilibrium vapor pressure over the interval 1-24K. The (T,n) phase diagram of Kr-nCH4 solid solutions is refined, and the region of two-phase states is determined. The contribution of the rotational subsystem, Crot, to the heat capacity of the solutions is separated. Analysis of Crot(T ) at T <3K makes it possible to estimate the effective conversion times τ and the energy gaps E1 and E2 between the tunneling levels of the A ,T and A ,E nuclear-spin species of CH4 molecules in the orientationally ordered subsystem and to determine the effective energy gaps E1 between the lowest levels of the A and T species. The relations τ(n ) and E1(n) stem from changes of the effective potential field in result of the replacement of CH4 molecules by Kr atoms at sites of the ordered sublattices. The effective gaps EL between a group of tunneling levels of the librational ground state and the nearest group of excited levels of the librational state of the ordered CH4 molecules in the solutions with n =0.90 (EL=52K) and 0.95 (EL=55K) is estimated.

  4. Ultrasonic detection of solid phase mass flow ratio of pneumatic conveying fly ash

    NASA Astrophysics Data System (ADS)

    Duan, Guang Bin; Pan, Hong Li; Wang, Yong; Liu, Zong Ming

    2014-04-01

    In this paper, ultrasonic attenuation detection and weight balance are adopted to evaluate the solid mass ratio in this paper. Fly ash is transported on the up extraction fluidization pneumatic conveying workbench. In the ultrasonic test. McClements model and Bouguer-Lambert-Beer law model were applied to formulate the ultrasonic attenuation properties of gas-solid flow, which can give the solid mass ratio. While in the method of weigh balance, the averaged mass addition per second can reveal the solids mass flow ratio. By contrast these two solid phase mass ratio detection methods, we can know, the relative error is less.

  5. Synthetic approaches to parabens molecularly imprinted polymers and their applications to the solid-phase extraction of river water samples.

    PubMed

    Beltran, A; Marcé, R M; Cormack, P A G; Borrull, F

    2010-09-10

    In this paper we describe the synthesis, characterisation and use of two distinct molecularly imprinted polymers (MIPs) prepared using esters of p-hydroxybenzoic acid (parabens) as templates: one MIP was synthesised by precipitation polymerisation using a semi-covalent molecularly imprinting strategy with methyl paraben as the template/target (MIP 1); the second MIP was prepared in monolithic form through a conventional non-covalent molecular imprinting strategy, with butyl paraben as the template (MIP 2). MIP 1 recognized methyl paraben, showed cross-selectivity for other parabens analytes used in the study and higher affinity towards these compounds than did a non-imprinted control polymer. Similarly, MIP 2 demonstrated higher affinity towards paraben analytes than a non-imprinted control polymer. For the analysis of environmental water samples, a solid-phase extraction (SPE) protocol was developed using MIP 2 as sorbent, and results were compared to a SPE using a commercial sorbent (Oasis HLB). With MIP 2 as sorbent and butyl paraben as target, when percolating 500 mL of river water spiked at 1 μg L(-1) through the SPE cartridge, and using 1 mL of isopropanol as cleaning solvent, a higher recovery of butyl 4-hydroxybenzoate (butyl paraben) and a cleaner chromatogram where achievable when using the MIP compared to the commercial sorbent.

  6. Application of solid phase microextraction for quantitation of polyunsaturated fatty acids in biological fluids.

    PubMed

    Birjandi, Afsoon Pajand; Mirnaghi, Fatemeh Sadat; Bojko, Barbara; Wąsowicz, Marcin; Pawliszyn, Janusz

    2014-12-16

    Development of a straightforward strategy for simultaneous quantitative analysis of nonesterified fatty acids (NEFA) species in biofluids is a challenging task because of the extreme complexity of fatty acid distribution in biological matrices. In this study, we present a direct immersion solid phase microextraction method coupled to a liquid chromatography-mass spectrometry platform (DI-SPME- HPLC-ESI -MS) for determination of unconjugated fatty acids (FA) in fish and human plasma. The proposed method was fully validated according to bioanalytical method validation guidelines. The LOD and LOQ were in the range of 0.5-2 and 5-12 ng/mL, respectively, with a linear dynamic range of 100 fold for each compound. Absolute and relative matrix effects were comprehensively evaluated and found to be in the acceptable range of 91-116%. The affinity constant (Ka) of individual FAs to protein albumin was determined to be 9.2 × 10(4) to 4.3 × 10(5) M(-1). The plasma protein binding (PPB%) was calculated and found to be in the range of 98.0-99.7% for different polyunsaturated fatty acids (PUFAs). The PUFAs under study were found at a high concentration range in fish plasma, whereas only a few were within quantification range in control human plasma. The method was successfully applied for monitoring PUFA changes during the operation in plasma samples obtained from patients undergoing cardiac surgery with the use of cardiopulmonary bypass (CPB). The most significant contribution induced by surgery was noticed in the concentration level of α-linolenic acid (18:3, ALA), arachidonic acid (20:4, AA), and docosahexanoic acid (22:6, DHA) soon after administration of CPB in all cases. PMID:25403310

  7. Anomalous bond length behavior and a new solid phase of bromine under pressure.

    PubMed

    Wu, Min; Tse, John S; Pan, Yuanming

    2016-01-01

    The behavior of diatomic molecular solids under pressure have attracted great interest and been extensively studied. Under ambient pressure, the structure of bromine is known to be a molecular phase (phase I). With increasing pressure, it transforms into an incommensurate phase (phase V) before eventually to a monoatomic phase (phase II). However, between phases I and V, the interatomic distance was found to first increase with pressure and then decreased abruptly. This anomalous bond length behavior is accompanied by the splitting of the Raman bands. These phenomena have not been resolved. Here we suggest a new solid phase that explains the Raman spectra. Furthermore, the anomalous bond length behavior is found to be the result of subtle second neighbor intermolecular interactions and is an intrinsic property of bromine in molecular phases. PMID:27156710

  8. Anomalous bond length behavior and a new solid phase of bromine under pressure

    PubMed Central

    Wu, Min; Tse, John S.; Pan, Yuanming

    2016-01-01

    The behavior of diatomic molecular solids under pressure have attracted great interest and been extensively studied. Under ambient pressure, the structure of bromine is known to be a molecular phase (phase I). With increasing pressure, it transforms into an incommensurate phase (phase V) before eventually to a monoatomic phase (phase II). However, between phases I and V, the interatomic distance was found to first increase with pressure and then decreased abruptly. This anomalous bond length behavior is accompanied by the splitting of the Raman bands. These phenomena have not been resolved. Here we suggest a new solid phase that explains the Raman spectra. Furthermore, the anomalous bond length behavior is found to be the result of subtle second neighbor intermolecular interactions and is an intrinsic property of bromine in molecular phases. PMID:27156710

  9. Anomalous bond length behavior and a new solid phase of bromine under pressure.

    PubMed

    Wu, Min; Tse, John S; Pan, Yuanming

    2016-05-09

    The behavior of diatomic molecular solids under pressure have attracted great interest and been extensively studied. Under ambient pressure, the structure of bromine is known to be a molecular phase (phase I). With increasing pressure, it transforms into an incommensurate phase (phase V) before eventually to a monoatomic phase (phase II). However, between phases I and V, the interatomic distance was found to first increase with pressure and then decreased abruptly. This anomalous bond length behavior is accompanied by the splitting of the Raman bands. These phenomena have not been resolved. Here we suggest a new solid phase that explains the Raman spectra. Furthermore, the anomalous bond length behavior is found to be the result of subtle second neighbor intermolecular interactions and is an intrinsic property of bromine in molecular phases.

  10. Solid-phase synthetic strategy and bioevaluation of a labeled delta-opioid receptor ligand Dmt-Tic-Lys for in vivo imaging.

    PubMed

    Josan, Jatinder S; Morse, David L; Xu, Liping; Trissal, Maria; Baggett, Brenda; Davis, Peg; Vagner, Josef; Gillies, Robert J; Hruby, Victor J

    2009-06-18

    A general solid-phase synthetic strategy is developed to prepare fluorescent and/or lanthanide-labeled derivatives of the delta-opioid receptor (deltaOR) ligand H-Dmt-Tic-Lys(R)-OH. The high delta-OR affinity (K(i) = 3 nM) and desirable in vivo characteristics of the Cy5 derivative 1 suggest its usefulness for structure-function studies and receptor localization and as a high-contrast noninvasive molecular marker for live imaging ex vivo or in vivo.

  11. Synthesis of functional nanocomposites based on solid-phase nanoreactors

    NASA Astrophysics Data System (ADS)

    Tretyakov, Yuri D.; Lukashin, Alexey V.; Eliseev, Andrei A.

    2004-09-01

    Approaches to the synthesis of functional nanocomposites based on zero-, one- and two-dimensional solid-state nanoreactors formed by zeolite cages, pores of mesoporous matrices, or interlayer cavities in layered compounds are considered. It is demonstrated that the use of solid-state nanoreactors opens up extensive opportunities for designing nanocomposites with specified physicochemical properties and makes it possible to avoid the aggregation of nanoparticles and to protect them from exposure to external factors, thus essentially facilitating the practical utility of these materials.

  12. DETERMINATION OF CHLOROETHENES IN ENVIRONMENTAL BIOLOGICAL SAMPLES USING GAS CHROMATOGRAPHY COUPLED WITH SOLID PHASE MICRO EXTRACTION

    EPA Science Inventory

    An analytical method has been developed to determine the chloroethene series, tetrachloroethene (PCE), trichloroethene (TCE),cisdichloroethene (cis-DCE) andtransdichloroethene (trans-DCE) in environmental biotreatment studies using gas chromatography coupled with a solid phase mi...

  13. EVALUATION OF SOLID PHASE MICROEXTRACTION FOR THE ANALYSIS OF HYDROPHILIC COMPOUNDS

    EPA Science Inventory

    Two commercially available solid phase microextractions (SPME) fibers, polyacrylate and carboxem/polydimethylsiloxane (PDMS), were evaluated for their ability to extract hydrophilic compounds from drinking water. Conditions, such as desorption time, desorption temperature, sample...

  14. Isostructural solid-solid phase transition in monolayers of soft core-shell particles at fluid interfaces: structure and mechanics.

    PubMed

    Rey, Marcel; Fernández-Rodríguez, Miguel Ángel; Steinacher, Mathias; Scheidegger, Laura; Geisel, Karen; Richtering, Walter; Squires, Todd M; Isa, Lucio

    2016-04-21

    We have studied the complete two-dimensional phase diagram of a core-shell microgel-laden fluid interface by synchronizing its compression with the deposition of the interfacial monolayer. Applying a new protocol, different positions on the substrate correspond to different values of the monolayer surface pressure and specific area. Analyzing the microstructure of the deposited monolayers, we discovered an isostructural solid-solid phase transition between two crystalline phases with the same hexagonal symmetry, but with two different lattice constants. The two phases corresponded to shell-shell and core-core inter-particle contacts, respectively; with increasing surface pressure the former mechanically failed enabling the particle cores to come into contact. In the phase-transition region, clusters of particles in core-core contacts nucleate, melting the surrounding shell-shell crystal, until the whole monolayer moves into the second phase. We furthermore measured the interfacial rheology of the monolayers as a function of the surface pressure using an interfacial microdisk rheometer. The interfaces always showed a strong elastic response, with a dip in the shear elastic modulus in correspondence with the melting of the shell-shell phase, followed by a steep increase upon the formation of a percolating network of the core-core contacts. These results demonstrate that the core-shell nature of the particles leads to a rich mechanical and structural behavior that can be externally tuned by compressing the interface, indicating new routes for applications, e.g. in surface patterning or emulsion stabilization.

  15. Isotope effects in dense solid hydrogen - Phase transition in deuterium at 190 + or - 20 GPa

    NASA Technical Reports Server (NTRS)

    Hemley, R. J.; Mao, H. K.

    1989-01-01

    Raman measurements of solid normal deuterium compressed in a diamond-anvil cell indicate that the material undergoes a structural phase transformation at 190 + or - 20 GPa and 77 K. Spectroscopically, the transition appears analogous to that observed in hydrogen at 145 + or - 5 GPa. The large isotope effect on the transition pressure suggests there is a significant vibrational contribution to the relative stability of the solid phases of hydrogen at very high densities.

  16. Phase transition of solid bismuth under high pressure

    NASA Astrophysics Data System (ADS)

    Chen, Hai-Yan; Xiang, Shi-Kai; Yan, Xiao-Zhen; Zheng, Li-Rong; Zhang, Yi; Liu, Sheng-Gang; Bi, Yan

    2016-10-01

    As a widely used pressure calibrator, the structural phase transitions of bismuth from phase I, to phase II, to phase III, and then to phase V with increasing pressure at 300 K have been widely confirmed. However, there are different structural versions for phase III, most of which are determined by x-ray diffraction (XRD) technology. Using x-ray absorption fine structure (XAFS) measurements combined with ab initio calculations, we show that the proposed incommensurate composite structure of bismuth of the three configurations is the best option. An abnormal continuous increase of the nearest-neighbor distance of phase III with elevated pressure is also observed. The electronic structure transformation from semimetal to metal is responsible for the complex behavior of structure transformation. Project supported by the National Natural Science Foundation of China (Grant Nos. 10904133, 11304294, 11274281, 11404006, and U1230201), the Development Foundation of China Academy of Engineering Physics (Grant Nos. 2015B0101004, 2013B0401062, and 2012A0101001), the Research Foundation of the Laboratory of Shock Wave and Detonation, China (Grant No. 9140C670201140C67282).

  17. New insights in Microbial Fuel Cells: novel solid phase anolyte.

    PubMed

    Tommasi, Tonia; Salvador, Gian Paolo; Quaglio, Marzia

    2016-01-01

    For the development of long lasting portable microbial fuel cells (MFCs) new strategies are necessary to overcome critical issues such as hydraulic pump system and the biochemical substrate retrieval overtime to sustain bacteria metabolism. The present work proposes the use of a synthetic solid anolyte (SSA), constituted by agar, carbonaceous and nitrogen sources dissolved into diluted seawater. Results of a month-test showed the potential of the new SSA-MFC as a long lasting low energy consuming system. PMID:27375205

  18. New insights in Microbial Fuel Cells: novel solid phase anolyte

    PubMed Central

    Tommasi, Tonia; Salvador, Gian Paolo; Quaglio, Marzia

    2016-01-01

    For the development of long lasting portable microbial fuel cells (MFCs) new strategies are necessary to overcome critical issues such as hydraulic pump system and the biochemical substrate retrieval overtime to sustain bacteria metabolism. The present work proposes the use of a synthetic solid anolyte (SSA), constituted by agar, carbonaceous and nitrogen sources dissolved into diluted seawater. Results of a month-test showed the potential of the new SSA-MFC as a long lasting low energy consuming system. PMID:27375205

  19. New insights in Microbial Fuel Cells: novel solid phase anolyte.

    PubMed

    Tommasi, Tonia; Salvador, Gian Paolo; Quaglio, Marzia

    2016-07-04

    For the development of long lasting portable microbial fuel cells (MFCs) new strategies are necessary to overcome critical issues such as hydraulic pump system and the biochemical substrate retrieval overtime to sustain bacteria metabolism. The present work proposes the use of a synthetic solid anolyte (SSA), constituted by agar, carbonaceous and nitrogen sources dissolved into diluted seawater. Results of a month-test showed the potential of the new SSA-MFC as a long lasting low energy consuming system.

  20. New insights in Microbial Fuel Cells: novel solid phase anolyte

    NASA Astrophysics Data System (ADS)

    Tommasi, Tonia; Salvador, Gian Paolo; Quaglio, Marzia

    2016-07-01

    For the development of long lasting portable microbial fuel cells (MFCs) new strategies are necessary to overcome critical issues such as hydraulic pump system and the biochemical substrate retrieval overtime to sustain bacteria metabolism. The present work proposes the use of a synthetic solid anolyte (SSA), constituted by agar, carbonaceous and nitrogen sources dissolved into diluted seawater. Results of a month-test showed the potential of the new SSA-MFC as a long lasting low energy consuming system.

  1. Analysis of the structure of synthetic and natural melanins by solid-phase

    SciTech Connect

    Duff, G.A.; Roberts, J.E.; Foster, N.

    1988-09-06

    The structures of one synthetic and two natural melanins are examined by solid-state NMR using cross polarization, magic angle sample spinning, and high-power proton decoupling. The structural features of synthetic dopa malanin are compared to those of melanin from malignant melanoma cells grown in culture and sepia melanin from squid ink. Natural abundance /sup 13/C and /sup 15/N spectra show resonances consistent with known pyrrolic and indolic structures within the heterogeneous biopolymer; /sup 13/C spectra indicate the presence of aliphatic residues in all three materials. These solid-phase experiments illustrate the promise of solid-phase NMR for elucidating structural from insoluble biomaterials.

  2. Phase relationships involving RDX and common solid propellant binders

    SciTech Connect

    Boyer, E.; Brown, P.W.; Kuo, K.K.

    1996-07-01

    The solubilities of the common propellant ingredients acetyl triethyl citrate (ATEC) and cellulose acetate butyrate (CAB) and their effects on RDX (cyclotrimethylenetrinitramine) unit cell dimensions were investigated. If there is appreciable solid solubility, solutions will form and will have enthalpies of fusion, melting temperatures, and other characteristics different from those of pure RDX. It is desirable to establish the properties of such mixtures when designing new propellant formulations. Samples were aged at an elevated temperature to speed the formation of solid solutions. A least-squares analysis of X-ray diffraction data was used to obtain the lattice parameters from which unit cell volume and solubility was deduced. Both ATEC and CAB caused an expansion of the unit cell, indicating the formation of a solid solution. The limit of solubility in the ATEC/RDX mixture appeared to be approximately 13 wt% ATEC, while the CAB/RDX limit is above 16 wt% CAB. In both mixes, the cell volume expanded linearly with increasing proportion of binder. The large amount of gas generated and high energy released during combustion make RDX very attractive for both rocket and gun propulsion applications. The absence of HCl in the combustion products makes RDX desirable on an environmental basis as well.

  3. Phase transitions of amorphous solid acetone in confined geometry investigated by reflection absorption infrared spectroscopy.

    PubMed

    Shin, Sunghwan; Kang, Hani; Kim, Jun Soo; Kang, Heon

    2014-11-26

    We investigated the phase transformations of amorphous solid acetone under confined geometry by preparing acetone films trapped in amorphous solid water (ASW) or CCl4. Reflection absorption infrared spectroscopy (RAIRS) and temperature-programmed desorption (TPD) were used to monitor the phase changes of the acetone sample with increasing temperature. An acetone film trapped in ASW shows an abrupt change in the RAIRS features of the acetone vibrational bands during heating from 80 to 100 K, which indicates the transformation of amorphous solid acetone to a molecularly aligned crystalline phase. Further heating of the sample to 140 K produces an isotropic solid phase, and eventually a fluid phase near 157 K, at which the acetone sample is probably trapped in a pressurized, superheated condition inside the ASW matrix. Inside a CCl4 matrix, amorphous solid acetone crystallizes into a different, isotropic structure at ca. 90 K. We propose that the molecularly aligned crystalline phase formed in ASW is created by heterogeneous nucleation at the acetone-water interface, with resultant crystal growth, whereas the isotropic crystalline phase in CCl4 is formed by homogeneous crystal growth starting from the bulk region of the acetone sample.

  4. Immobilized metal-ion affinity partitioning of NAD(+)-dependent dehydrogenases in poly(ethylene glycol)-dextran two-phase systems.

    PubMed

    Pesliakas, H; Zutautas, V; Baskeviciute, B

    1994-08-26

    Affinity partitioning of yeast alcohol dehydrogenase (YADH), lactate dehydrogenase from rabbit muscle (MLDH) and lactate and malate dehydrogenases from pig heart (HLDH and HMDH, respectively) were studied in aqueous two-phase systems containing metal ions (Cu2+, Ni2+, Zn2+ and Cd2+) chelated by iminodiacetate-poly(ethylene glycol) (IDA-PEG). The partitioning behaviour of the enzymes in the presence of Cu(II)-IDA-PEG was studied as a function of the concentration of NaCl, the pH of the medium and the concentration of added selected agents. It was demonstrated that the partition effect (delta log K) of dehydrogenases in the presence of Cu(II)-IDA-PEG and the affinity of enzymes for immobilized Cu2+ ions increases in the order MLDH > YADH > HMDH > or = HLDH. It was shown that the determined variations in the enzyme affinities for Cu(II)-IDA-PEG might be related to the differences in the content of histidine residues accessible to the solvent.

  5. A novel nickel-chelated surfactant for affinity-based aqueous two-phase micellar extraction of histidine-rich protein.

    PubMed

    Wang, Shuo; Xiong, Neng; Dong, Xiao-Yan; Sun, Yan

    2013-12-13

    Aqueous two-phase micellar systems (ATPMSs) composed of nonionic surfactants are considered promising for the separation and purification of proteins. To improve the specificity of ATPMSs, a novel nickel-chelated surfactant was prepared by successive modifications of Triton X-114 (TX). Characterizations by Fourier transformation infrared spectroscopy demonstrated the successful synthesis of the nickel-chelated surfactant (TX-Ni). The cloud point, critical micelle concentration (CMC), molecular interaction parameter and micelle size were measured for the mixed surfactant system of TX-Ni and TX to achieve a full understanding of their aggregation behaviors. The results showed that mixed micelles were formed, and the cloud point increased with the mole fraction of TX-Ni because TX-Ni had a more hydrophilic head group than TX. Moreover, the reduction of micelle size revealed by light scattering experiments indicated that the insertion of TX-Ni inhibited the micellar growth due to the increased steric and electrostatic repulsion. Finally, the efficiency of TX-Ni as an affinity surfactant was demonstrated by the affinity partitioning of histidine-tagged enhanced green fluorescent protein with an over 20-fold increase of the partition coefficient (from 0.60 to 12.42). This affinity-based ATPMS is thus considered promising for providing a versatile platform for the separation of histidine-rich proteins.

  6. The acidity and proton affinity of the damaged base 1,N6-ethenoadenine in the gas phase versus in solution: intrinsic reactivity and biological implications.

    PubMed

    Liu, Min; Xu, Meng; Lee, Jeehiun K

    2008-08-01

    1,N(6)-ethenoadenine (epsilonA) is a highly mutagenic lesion that is excised from human DNA by the enzyme alkyladenine DNA glycosylase (AAG). In an effort to understand the intrinsic properties of 1,N(6)-ethenoadenine, we examined its gas phase acidity and proton affinity using quantum mechanical calculations and mass spectrometric experimental methods. We measure two acidities for epsilonA: a more acidic site (DeltaH(acid) = 332 kcal mol(-1); DeltaG(acid) = 325 kcal mol(-1)) and a less acidic site (DeltaH(acid) = 367 kcal mol(-1); DeltaG(acid) = 360 kcal mol(-1)). We also find that the proton affinity of the most basic site of 1,N(6)-ethenoadenine is 232-233 kcal mol(-1) (GB = 224 kcal mol(-1)). These measurements, when compared to calculations, establish that, under our experimental conditions, we have only the canonical tautomer of 1,N(6)-ethenoadenine present. We also compare the gas phase acidic properties of epsilonA with that of the normal bases adenine and guanine and find that epsilonA is the most acidic. This supports the theory that AAG and other related enzymes may cleave damaged bases as anions. Furthermore, comparison of the gas phase and aqueous acidities indicates that the nonpolar environment of the enzyme enhances the acidity differences of epsilonA versus adenine and guanine. PMID:18593189

  7. Solid-matrix fluorescence and phosphorescence and solid-phase microextraction of polycyclic aromatic hydrocarbons with hydrophobic paper

    SciTech Connect

    Ackerman, A.H.; Hurtubise, R.J.

    1999-07-01

    Solid-matrix fluorescence (SMF) and solid-matrix phosphorescence (SMP) have been used in conjunction with solid-phase microextraction to characterize mixtures of polycyclic aromatic hydrocarbons (PAHs) isolated from water. Whatman 1PS paper was used to extract the PAH from water, and then the isolated PAHs were directly identified on the paper by obtaining SMF and SMP spectra. The SMF and SMP properties of 10 PAH were obtained, and the PAHs in a two-component mixture, a three-component mixture, and a four-component mixture were easily identified by a combination of SMF and SMP. No external heavy atom was needed to acquire the SMP data. Benzo[{ital e}]pyrene gave a limit of detection of 6.2 pg/mL with SMP, and with SMF benzo[{ital a}]pyrene gave a limit of detection of 19 pg/mL. {copyright} {ital 1999} {ital Society for Applied Spectroscopy}

  8. Synthesis of gold-silica composite nanowires through solid-liquid-solid phase growth.

    PubMed

    Paulose, Maggie; Varghese, Oomman K; Grimes, Craig A

    2003-08-01

    Nanoscale wires of silicon oxide, and silicon oxide with embedded gold-silicide nanospheres, are synthesized by heating of a gold-coated silicon wafer at temperatures of 1000 degrees C or above, with the resulting wires having diameters ranging from 30 to 150 nm and lengths of approximately 1 mm. This simple fabrication process should make possible economical bulk production of nanowires. Studies indicate that the growth of these gold-silica composite nanowires occurs directly on the silicon wafer by a solid-liquid-solid mechanism. PMID:14598450

  9. Determination of binding constants by affinity capillary electrophoresis, electrospray ionization mass spectrometry and phase-distribution methods

    PubMed Central

    Chen, Zhi; Weber, Stephen G.

    2008-01-01

    Many methods for determining intermolecular interactions have been described in the literature in the past several decades. Chief among them are methods based on spectroscopic changes, particularly those based on absorption or nuclear magnetic resonance (NMR) [especially proton NMR (1H NMR)]. Recently, there have been put forward several new methods that are particularly adaptable, use very small quantities of material, and do not place severe requirements on the spectroscopic properties of the binding partners. This review covers new developments in affinity capillary electrophoresis, electrospray ionization mass spectrometry (ESI-MS) and phasetransfer methods. PMID:19802330

  10. Existence of Solutions for a Mathematical Model Related to Solid-Solid Phase Transitions in Shape Memory Alloys

    NASA Astrophysics Data System (ADS)

    Bonetti, Elena; Colli, Pierluigi; Fabrizio, Mauro; Gilardi, Gianni

    2016-01-01

    We consider a strongly nonlinear PDE system describing solid-solid phase transitions in shape memory alloys. The system accounts for the evolution of an order parameter χ (related to different symmetries of the crystal lattice in the phase configurations), of the stress (and the displacement u), and of the absolute temperature ϑ. The resulting equations present several technical difficulties to be tackled; in particular, we emphasize the presence of nonlinear coupling terms, higher order dissipative contributions, possibly multivalued operators. As for the evolution of temperature, a highly nonlinear parabolic equation has to be solved for a right hand side that is controlled only in L 1. We prove the existence of a solution for a regularized version by use of a time discretization technique. Then, we perform suitable a priori estimates which allow us pass to the limit and find a weak global-in-time solution to the system.

  11. Simulating Solid-Solid Phase Transition in Shape-Memory Alloy Microstructure by Face-Offsetting Method

    SciTech Connect

    Bellur Ramaswamy, Ravi S.; Tortorelli, Daniel A.; Fried, Eliot; Jiao Xiangmin

    2008-02-15

    Advances in the understanding of martensitic transformations (diffusionless, solid-solid phase transformations) have been instrumental to the recent discovery of new low hysteresis alloys. However, some key fundamental issues must be better understood to design still better alloys. Restricting attention to antiplane shear, we use finite element analysis to model the shape-memory alloy microstructure within the Abeyaratne-Knowles continuum thermomechanical framework and use an interface kinetic relation of the kind proposed by Rosakis and Tsai. Geometric singularities and topological changes associated with microstructural evolution pose significant numerical challenges. We address such challenges with a recently developed front-tracking scheme called the face-offsetting method (FOM) to explicitly model phase interfaces. Initial results demonstrate the effectiveness of FOM in resolving needle-like twinned microstructures.

  12. Solid phase synthesis of complex natural products and libraries thereof.

    PubMed

    Nicolaou, K C; Pfefferkorn, J A

    2001-01-01

    Natural products have served as an important source of medicinal compounds and pharmaceutical leads over the last century. Within the last 10 years, significant interest has developed in applying combinatorial chemistry techniques to the study of natural products and their biological activities. In this review, we examine several representative efforts wherein natural product skeletons have been constructed or immobilized on solid support and subsequently derivatized, giving rise to analog libraries useful in understanding the structure-activity relationships of the parent natural product. Issues such as target selection, library design, linker development, automation, and library characterization are addressed. PMID:11774224

  13. Pentaerythrityltetramine scaffolds for solid-phase combinatorial chemistry.

    PubMed

    Virta, Pasi; Leppänen, Marika; Lönnberg, Harri

    2004-03-19

    Straightforward synthesis for two pentaerythrityltetramine precursors, 2,2-bis(azidomethyl)propane-1,3-diamine (1) and 2-[N-(allyloxycarbonyl)aminomethyl]-2-azidomethylpropane-1,3-diamine (2), has been described. Both propane-1,3-diamines have been attached by reductive amination to a solid-supported backbone amide linker derived from 4-(4-formyl-3,5-dimethoxyphenoxy)butyric acid. The presence of the two methoxy substituents on the linker is essential to avoid cross-linking between two linkers. The remaining free primary amino group of the propane-1,3-diamine moiety may then be selectively acylated with an appropriately protected amino acid using conventional N,N-dicyclohexylcarbodiimide/1-hydroxybenzotriazole (DCC/HOBt) activation without any interference by the secondary amino function. The latter group may be subsequently acylated by an anhydride method. Sequential reduction of the azido group and removal of the allyloxycarbonyl protection from 2 allow further coupling of two different amino acids, and hence, this handle may be utilized in construction of branched structures containing four different amino acids or peptides. Solid-supported 1 may, in turn, be used for the synthesis of similar constructs containing two identical branches. It is worth noting that no acid-labile protecting groups are required in this approach, and hence, this dimension may be saved for the cleavage of the linker. The applicability of the scaffolds to library synthesis has been demonstrated by preparation of 11 pentaerythrityl-branched tetra- and octapeptides.

  14. Development of a solid waste fired fluidized boiler, phase 1

    NASA Astrophysics Data System (ADS)

    Preuit, L. C.

    1982-02-01

    Tests were conducted to develop solid waste fired fluid bed boiler (FBB) technology. The fluid bed facility incorporates water tubes for heat extraction and can burn over seven tons of refuse derived fuel per day. Municipal solid waste from surrounding communities is shredded and air classified to remove inerts and recoverable materials. Current and past work shows that a fluid bed boiler will be able to operate at excess air levels well below those presently required by conventional grate-type waste fired boilers, and with comparable or superior combustion efficiencies. Tests were conducted to investigate: the range of process conditions over which satisfactory operation can be maintained; suppression of acid gas emissions; recycle of elutriated fines back to the fluid bed; and fuel technology. In previous testing, operation was stable while firing refuse derived fuel for the duration of a 300-hour test. No agglomeration of bed material or slag formation was experienced. Low excess air, low exhaust gas emissions, and constant bed temperature demonstrated feasibility of steam generation from fluid bed combustion.

  15. Solid and Vapor Phase UV Photocathodes for Gaseous Detectors

    SciTech Connect

    Vasileiadis, G.; Malamud, G.; Mine, P.; Vartsky, D.; /Ecole Polytechnique

    2012-09-20

    We measured the relative quantum efficiency of four organic materials: tetrathiafulvalene and bis(cyclopentadienyl)magnesium in the solidphase and t-butylferrocene and n-butylferrocene in the vapour phase. The measurements were performed in the wavelength range of 150-220 nm. We also present a new quantum efficiency measurement of ethylferrocene. The three ferrocene derivatives exhibit relatively high quantum efficiency.

  16. Altered condensed-phase electron affinities of carbonyl-/sup 13/C-, /sup 14/C, and -/sup 17/O- substituted ketones

    SciTech Connect

    Lauricella, T.L.; Pescatore, J.A. Jr.; Reiter, R.C.; Stevenson, R.D.; Stevenson, G.R.

    1988-06-16

    Electron spin resonance experiments have shown that the solution affinities of both benzoquinone (BQ) and benzophenone (BZO) in liquid ammonia are diminished when a /sup 13/C replaces the /sup 12/C in the carbonyl position. For the reaction *R + R/sup .-/ reversible *R/sup .-/ + R, where *R represents the /sup 13/C-substituted material (either BZO-13C or BQ-13C), the equilibrium constants (K/sub eq/) are 0.80 and 0.50 at -75/sup 0/ C for the BQ and BZO systems, respectively. The reduction of radioactive samples of benzophenone (mixtures of BZO and BZO-14C, /sup 14/C substitution at the carbonyl carbon) with deficient amounts of sodium metal in liquid ammonia followed by removal of the ammonia leaves a solid mixture of benzophenone and benzophenone ketyl. Sublimation of the neutral benzophenone from the anion radical salt produces benzophenone that is enhanced in radioactivity relative to the starting BZO/BZO-14C mixture. This enhancement in radioactivity is consistent with the equilibrium constant again being less than unity when *R represents the /sup 14/C-substituted benzophenone. In contrast to these results, substitution of the oxygen atom with /sup 17/O results in an increase in the relative solution electron affinity. This is explained in terms of the increase in bonding involving the oxygen upon reduction, due to ion association.

  17. Solid phase stability of molybdenum under compression: Sound velocity measurements and first-principles calculations

    SciTech Connect

    Zhang, Xiulu; Liu, Zhongli; Jin, Ke; Xi, Feng; Yu, Yuying; Tan, Ye; Dai, Chengda; Cai, Lingcang

    2015-02-07

    The high-pressure solid phase stability of molybdenum (Mo) has been the center of a long-standing controversy on its high-pressure melting. In this work, experimental and theoretical researches have been conducted to check its solid phase stability under compression. First, we performed sound velocity measurements from 38 to 160 GPa using the two-stage light gas gun and explosive loading in backward- and forward-impact geometries, along with the high-precision velocity interferometry. From the sound velocities, we found no solid-solid phase transition in Mo before shock melting, which does not support the previous solid-solid phase transition conclusion inferred from the sharp drops of the longitudinal sound velocity [Hixson et al., Phys. Rev. Lett. 62, 637 (1989)]. Then, we searched its structures globally using the multi-algorithm collaborative crystal structure prediction technique combined with the density functional theory. By comparing the enthalpies of body centered cubic structure with those of the metastable structures, we found that bcc is the most stable structure in the range of 0–300 GPa. The present theoretical results together with previous ones greatly support our experimental conclusions.

  18. Theoretical study on phase coexistence in ferroelectric solid solutions near the tricritical point

    SciTech Connect

    Lu, Xiaoyan E-mail: dzk@psu.edu; Li, Hui; Zheng, Limei; Cao, Wenwu

    2015-04-07

    Phase coexistence in ferroelectric solid solutions near the tricritical point has been theoretically analyzed by using the Landau-Devonshire theory. Results revealed that different phases having similar potential wells could coexist in a narrow composition range near the tricritical point in the classical Pb(Zr{sub 1−x}Ti{sub x})O{sub 3} system. The potential barrier between potential wells increases with the decrease of temperature. Coexisting phases or different domains of the same phase can produce adaptive strains to maintain atomic coherency at the interfaces or domain walls. Such compatibility strains have influence on the energy potential as well as the stability of relative phases, leading to the appearance of energetically unfavorable monoclinic phases. Those competing and coexisting phases also construct an easy phase transition path with small energy barrier in between, so that very small stimuli can produce large response in compositions near the morphotropic phase boundary, especially near the tricritical point.

  19. Molecularly imprinted macroporous monoliths for solid-phase extraction: Effect of pore size and column length on recognition properties.

    PubMed

    Vlakh, E G; Stepanova, M A; Korneeva, Yu M; Tennikova, T B

    2016-09-01

    The series of macroporous monolithic molecularly imprinted monoliths differed by pore size, column length (volume) and amount of template used for imprinting was synthesized using methacrylic acid and glycerol dimethacrylate as co-monomers and antibiotic ciprofloxacin as a template. The prepared monoliths were characterized regarding to their permeability, pore size, porosity, and resistance to the flow of a mobile phase. The surface morphology was also analyzed. The slight dependence of imprinting factor on flow rate, as well as its independence on pore size of macroporous molecularly imprinted monolithic media was observed. The column obtained at different conditions exhibited different affinity of ciprofloxacin to the imprinted sites that was characterized with Kdiss values in the range of 10(-5)-10(-4)M. The solid-phase extraction of ciprofloxacin from such biological liquids as human blood serum, human urine and cow milk serum was performed using the developed monolithic columns. In all cases, the extraction was found to be 95.0-98.6%. Additionally, the comparison of extraction of three fluoroqinolone analogues, e.g. ciprofloxacin, levofloxacin and moxifloxacin, from human blood plasma was carried out. Contrary to ciprofloxacin extracted with more than 95%, this parameter did not exceed 40% for its analogues. PMID:27433985

  20. C-Terminal Protein Characterization by Mass Spectrometry using Combined Micro Scale Liquid and Solid-Phase Derivatization

    PubMed Central

    Nika, Heinz; Nieves, Edward; Hawke, David H.; Angeletti, Ruth Hogue

    2013-01-01

    A sample preparation method for protein C-terminal peptide isolation has been developed. In this strategy, protein carboxylate glycinamidation was preceded by carboxyamidomethylation and optional α- and ϵ-amine acetylation in a one-pot reaction, followed by tryptic digestion of the modified protein. The digest was adsorbed on ZipTipC18 pipette tips for sequential peptide α- and ϵ-amine acetylation and 1-ethyl-(3-dimethylaminopropyl) carbodiimide-mediated carboxylate condensation with ethylenediamine. Amino group-functionalized peptides were scavenged on N-hydroxysuccinimide-activated agarose, leaving the C-terminal peptide in the flow-through fraction. The use of reversed-phase supports as a venue for peptide derivatization enabled facile optimization of the individual reaction steps for throughput and completeness of reaction. Reagents were exchanged directly on the support, eliminating sample transfer between the reaction steps. By this sequence of solid-phase reactions, the C-terminal peptide could be uniquely recognized in mass spectra of unfractionated digests of moderate complexity. The use of the sample preparation method was demonstrated with low-level amounts of a model protein. The C-terminal peptides were selectively retrieved from the affinity support and proved highly suitable for structural characterization by collisionally induced dissociation. The sample preparation method provides for robustness and simplicity of operation using standard equipment readily available in most biological laboratories and is expected to be readily expanded to gel-separated proteins. PMID:23543807

  1. Thermoelastic properties of solid phases: C++ object oriented library “SolidEOS”

    NASA Astrophysics Data System (ADS)

    Churakov, Sergey V.

    2005-07-01

    A new object-oriented C++ library (SolidEOS) for calculating the thermoelastic properties of solids is presented. The implementation is based on the Mie-Grüneisen-Debye equation of state (EOS) augmented by lowest order correction for anharmonicity. Several commonly used static EOS like Birch-Murnaghan and Vinet models are available. Although some widely used approximation for the Debye-Grüneisen parameter and static EOS are implemented, the final behaviour of the EOS can be easily modified by overloading predefined virtual functions. The article provides a basic physical background of the modern theory of high-pressure EOS. The detailed documentation of the class hierarchy is summarized in the appendix, which accompanies the source. Several examples of practical use are given in the appendix as well. The library is appropriate for applications in geophysics, petrology, material science or any other field where thermodynamic and elastic properties of solids are relevant. The source code is available from the Computers & Geoscience software archive.

  2. Isostructural solid-solid phase transition in monolayers of soft core-shell particles at fluid interfaces: structure and mechanics.

    PubMed

    Rey, Marcel; Fernández-Rodríguez, Miguel Ángel; Steinacher, Mathias; Scheidegger, Laura; Geisel, Karen; Richtering, Walter; Squires, Todd M; Isa, Lucio

    2016-04-21

    We have studied the complete two-dimensional phase diagram of a core-shell microgel-laden fluid interface by synchronizing its compression with the deposition of the interfacial monolayer. Applying a new protocol, different positions on the substrate correspond to different values of the monolayer surface pressure and specific area. Analyzing the microstructure of the deposited monolayers, we discovered an isostructural solid-solid phase transition between two crystalline phases with the same hexagonal symmetry, but with two different lattice constants. The two phases corresponded to shell-shell and core-core inter-particle contacts, respectively; with increasing surface pressure the former mechanically failed enabling the particle cores to come into contact. In the phase-transition region, clusters of particles in core-core contacts nucleate, melting the surrounding shell-shell crystal, until the whole monolayer moves into the second phase. We furthermore measured the interfacial rheology of the monolayers as a function of the surface pressure using an interfacial microdisk rheometer. The interfaces always showed a strong elastic response, with a dip in the shear elastic modulus in correspondence with the melting of the shell-shell phase, followed by a steep increase upon the formation of a percolating network of the core-core contacts. These results demonstrate that the core-shell nature of the particles leads to a rich mechanical and structural behavior that can be externally tuned by compressing the interface, indicating new routes for applications, e.g. in surface patterning or emulsion stabilization. PMID:26948023

  3. Enhanced denitrification of Pseudomonas stutzeri by a bioelectrochemical system assisted with solid-phase humin.

    PubMed

    Xiao, Zhixing; Awata, Takanori; Zhang, Dongdong; Zhang, Chunfang; Li, Zhiling; Katayama, Arata

    2016-07-01

    The denitrification reactions performed by Pseudomonas stutzeri JCM20778 were enhanced electrochemically with the use of solid-phase humin, although P. stutzeri itself was incapable of receiving electrons directly from the graphite electrode. Electrochemically reduced humin enhanced the microbial, but not abiotic, denitrification reactions. Electric current and cyclic voltammetry analyses suggested that the solid-phase humin functioned as an electron donor for the denitrification reactions of P. stutzeri. Nitrogen balance study and the estimation of the first-order rate constants of the consecutive denitrification reactions suggested that the solid-phase humin enhanced all reducing reactions from nitrate to nitrogen gas. Considering the wide distribution of humin in the environment, the findings that solid-phase humin can assist in electron transfer, from the electrode to a denitrifying bacterium that has little ability to directly utilize external electrons, has important implications for the widespread application of bioelectrochemical systems assisted by solid-phase humin for enhancing microbial denitrification.

  4. Determination of melamine in aquaculture feed samples based on molecularly imprinted solid-phase extraction.

    PubMed

    Lian, Ziru; Liang, Zhenlin; Wang, Jiangtao

    2015-10-01

    This research highlights the application of highly efficient molecularly imprinted solid-phase extraction for the preconcentration and analysis of melamine in aquaculture feed samples. Melamine-imprinted polymers were synthesized employing methacrylic acid and ethylene glycol dimethacrylate as functional monomer and cross-linker, respectively. The characteristics of obtained polymers were evaluated by scanning electron microscopy, Fourier transform infrared spectroscopy and binding experiments. The imprinted polymers showed an excellent adsorption ability for melamine and were applied as special solid-phase extraction sorbents for the selective cleanup of melamine. An off-line molecularly imprinted solid-phase extraction procedure was developed for the separation and enrichment of melamine from aquaculture feed samples prior to high-performance liquid chromatography analysis. Optimum molecularly imprinted solid-phase extraction conditions led to recoveries of the target in spiked feed samples in the range 84.6-96.6% and the relative standard deviation less than 3.38% (n = 3). The aquaculture feed sample was determined, and there was no melamine found. The results showed that the molecularly imprinted solid-phase extraction protocols permitted the sensitive, uncomplicated and inexpensive separation and pre-treatment of melamine in aquaculture feed samples.

  5. Lignin isolated from steam-exploded eucalyptus wood chips by phase separation and its affinity to Trichoderma reesei cellulase.

    PubMed

    Nonaka, Hiroshi; Kobayashi, Ai; Funaoka, Masamitsu

    2013-07-01

    Steam-exploded eucalyptus wood chips were treated with p-cresol and 72% sulfuric acid at ambient temperature. Steam-exploded lignin was isolated as acetone-soluble and diethyl ether-insoluble compounds from the cresol layer. The lignin extraction yield was only 47%, and the amount of cresol grafted to lignin was much less than that in the case of eucalyptus lignin without steam explosion. Clearly, the steam explosion process depolymerized native lignin, and simultaneously, promoted polymerization via labile benzyl positions. The steam-exploded eucalyptus lignin adsorbed more Trichoderma reesei cellulase; however, its enzymatic activity was less than that of eucalyptus lignin that did not undergo steam explosion. It is evident that pretreatment potentially affects the affinity between lignin and cellulase and the resultant saccharification efficiency.

  6. The solid phase stress tensor in porous media mechanics and the Hill-Mandel condition

    NASA Astrophysics Data System (ADS)

    Gray, William G.; Schrefler, Bernhard A.; Pesavento, Francesco

    2009-03-01

    An assessment of the stress tensors used currently for the modeling of partially saturated porous media is made which includes concepts like total stress, solid phase stress, and solid pressure. Thermodynamically constrained averaging theory is used to derive the solid phase stress tensor. It is shown that in the upscaling procedure the Hill conditions are satisfied, which is not trivial. The stress tensor is then compared to traditional stress measures. The physical meaning of two forms of solid pressure and of the Biot coefficient is clarified. Finally, a Bishop-Skempton like form of the stress tensor is obtained and a form of the total stress tensor that does not make use of the effective stress concept.

  7. Solid phase sequencing of double-stranded nucleic acids

    DOEpatents

    Fu, Dong-Jing; Cantor, Charles R.; Koster, Hubert; Smith, Cassandra L.

    2002-01-01

    This invention relates to methods for detecting and sequencing of target double-stranded nucleic acid sequences, to nucleic acid probes and arrays of probes useful in these methods, and to kits and systems which contain these probes. Useful methods involve hybridizing the nucleic acids or nucleic acids which represent complementary or homologous sequences of the target to an array of nucleic acid probes. These probe comprise a single-stranded portion, an optional double-stranded portion and a variable sequence within the single-stranded portion. The molecular weights of the hybridized nucleic acids of the set can be determined by mass spectroscopy, and the sequence of the target determined from the molecular weights of the fragments. Nucleic acids whose sequences can be determined include nucleic acids in biological samples such as patient biopsies and environmental samples. Probes may be fixed to a solid support such as a hybridization chip to facilitate automated determination of molecular weights and identification of the target sequence.

  8. Biological nitrate removal from water and wastewater by solid-phase denitrification process.

    PubMed

    Wang, Jianlong; Chu, Libing

    2016-11-01

    Nitrate pollution in receiving waters has become a serious issue worldwide. Solid-phase denitrification process is an emerging technology, which has received increasing attention in recent years. It uses biodegradable polymers as both the carbon source and biofilm carrier for denitrifying microorganisms. A vast array of natural and synthetic biopolymers, including woodchips, sawdust, straw, cotton, maize cobs, seaweed, bark, polyhydroxyalkanoate (PHA), polycaprolactone (PCL), polybutylene succinate (PBS) and polylactic acid (PLA), have been widely used for denitrification due to their good performance, low cost and large available quantities. This paper presents an overview on the application of solid-phase denitrification in nitrate removal from drinking water, groundwater, aquaculture wastewater, the secondary effluent and wastewater with low C/N ratio. The types of solid carbon source, the influencing factors, the microbial community of biofilm attached on the biodegradable carriers, the potential adverse effect, and the cost of denitrification process are introduced and evaluated. Woodchips and polycaprolactone are the popular and competitive natural plant-like and synthetic biodegradable polymers used for denitrification, respectively. Most of the denitrifiers reported in solid-phase denitrification affiliated to the family Comamonadaceae in the class Betaproteobacteria. The members of genera Diaphorobacter, Acidovorax and Simplicispira were mostly reported. In future study, more attention should be paid to the simultaneous removal of nitrate and toxic organic contaminants such as pesticide and PPCPs by solid-phase denitrification, to the elucidation of the metabolic and regulatory relationship between decomposition of solid carbon source and denitrification, and to the post-treatment of the municipal secondary effluent. Solid-phase denitrification process is a promising technology for the removal of nitrate from water and wastewater.

  9. Biological nitrate removal from water and wastewater by solid-phase denitrification process.

    PubMed

    Wang, Jianlong; Chu, Libing

    2016-11-01

    Nitrate pollution in receiving waters has become a serious issue worldwide. Solid-phase denitrification process is an emerging technology, which has received increasing attention in recent years. It uses biodegradable polymers as both the carbon source and biofilm carrier for denitrifying microorganisms. A vast array of natural and synthetic biopolymers, including woodchips, sawdust, straw, cotton, maize cobs, seaweed, bark, polyhydroxyalkanoate (PHA), polycaprolactone (PCL), polybutylene succinate (PBS) and polylactic acid (PLA), have been widely used for denitrification due to their good performance, low cost and large available quantities. This paper presents an overview on the application of solid-phase denitrification in nitrate removal from drinking water, groundwater, aquaculture wastewater, the secondary effluent and wastewater with low C/N ratio. The types of solid carbon source, the influencing factors, the microbial community of biofilm attached on the biodegradable carriers, the potential adverse effect, and the cost of denitrification process are introduced and evaluated. Woodchips and polycaprolactone are the popular and competitive natural plant-like and synthetic biodegradable polymers used for denitrification, respectively. Most of the denitrifiers reported in solid-phase denitrification affiliated to the family Comamonadaceae in the class Betaproteobacteria. The members of genera Diaphorobacter, Acidovorax and Simplicispira were mostly reported. In future study, more attention should be paid to the simultaneous removal of nitrate and toxic organic contaminants such as pesticide and PPCPs by solid-phase denitrification, to the elucidation of the metabolic and regulatory relationship between decomposition of solid carbon source and denitrification, and to the post-treatment of the municipal secondary effluent. Solid-phase denitrification process is a promising technology for the removal of nitrate from water and wastewater. PMID:27396522

  10. Structural and optical properties of solid-phase singlet oxygen photosensitizers based on fullerene aqueous suspensions

    NASA Astrophysics Data System (ADS)

    Belousova, I. M.; Belousov, V. P.; Kiselev, V. M.; Murav'eva, T. D.; Kislyakov, I. M.; Sirotkin, A. K.; Starodubtsev, A. M.; Kris'ko, T. K.; Bagrov, I. V.; Ermakov, A. V.

    2008-11-01

    The relationship between the structural and photosensitizing properties of solid-phase particles of fullerene C60 in aqueous suspensions is studied using the methods of absorption spectroscopy, electron spin resonance spectroscopy (ESR), X-ray diffraction, and spectrophotometry of solutions of singlet oxygen chemical traps—histidine in combination with p-nitrosodimethylaniline. Two new variants are proposed for obtaining aqueous suspensions of particles of solid-phase fullerene whose structures are disordered and whose degrees of amorphization are 67 and 40%, respectively. It is shown that an increase in the disorder of the structure of particles in suspensions and a decrease in their average size facilitate an increase in the formation efficiency of singlet oxygen by solid-phase fullerene presumably due to an in increase in the concentration of surface localized excitons.

  11. In situ transmission electron microscopy of solid-liquid phase transition of silica encapsulated bismuth nanoparticles

    NASA Astrophysics Data System (ADS)

    Hu, Jianjun; Hong, Yan; Muratore, Chris; Su, Ming; Voevodin, Andrey A.

    2011-09-01

    The solid-liquid phase transition of silica encapsulated bismuth nanoparticles was studied by in situ transmission electron microscopy (TEM). The nanoparticles were prepared by a two-step chemical synthesis process involving thermal decomposition of organometallic precursors for nucleating bismuth and a sol-gel process for growing silica. The microstructural and chemical analyses of the nanoparticles were performed using high-resolution TEM, Z-contrast imaging, focused ion beam milling, and X-ray energy dispersive spectroscopy. Solid-liquid-solid phase transitions of the nanoparticles were directly recorded by electron diffractions and TEM images. The silica encapsulation of the nanoparticles prevented agglomeration and allowed particles to preserve their original volume upon melting, which is desirable for applications of phase change nanoparticles with consistently repeatable thermal properties.

  12. In situ transmission electron microscopy of solid-liquid phase transition of silica encapsulated bismuth nanoparticles.

    PubMed

    Hu, Jianjun; Hong, Yan; Muratore, Chris; Su, Ming; Voevodin, Andrey A

    2011-09-01

    The solid-liquid phase transition of silica encapsulated bismuth nanoparticles was studied by in situ transmission electron microscopy (TEM). The nanoparticles were prepared by a two-step chemical synthesis process involving thermal decomposition of organometallic precursors for nucleating bismuth and a sol-gel process for growing silica. The microstructural and chemical analyses of the nanoparticles were performed using high-resolution TEM, Z-contrast imaging, focused ion beam milling, and X-ray energy dispersive spectroscopy. Solid-liquid-solid phase transitions of the nanoparticles were directly recorded by electron diffractions and TEM images. The silica encapsulation of the nanoparticles prevented agglomeration and allowed particles to preserve their original volume upon melting, which is desirable for applications of phase change nanoparticles with consistently repeatable thermal properties.

  13. The Use of Functional Nucleic Acids in Solid-Phase Fluorimetric Assays

    NASA Astrophysics Data System (ADS)

    Rupcich, Nicholas; Nutiu, Razvan; Shen, Yutu; Li, Yingfu; Brennan, John D.

    The past 15 years have seen a revolution in the area of functional nucleic acid (FNA) research since the demonstration that single-stranded RNA and DNA species can be used for both ligand binding and catalysis. An emerging area of application for such species is in the development of solid-phase fluorimetric assays for biosensing, proteomics, and drug screening purposes. In this chapter, the methods for immobilization of functional nucleic acids are briefly reviewed, with emphasis on emerging technologies such as sol-gel encapsulation. Methods for generating fluorescence signals from aptamers and nucleic acid enzymes are then described, and the use of such species in solid-phase fluorimetric assays is then discussed. Unique features of sol-gel based materials for the development of solid-phase assays are highlighted, and some emerging applications of immobilized FNA species are discussed.

  14. The use of coal in a solid phase reduction of iron oxide

    NASA Astrophysics Data System (ADS)

    Nokhrina, O. I.; Rozhihina, I. D.; Hodosov, I. E.

    2015-09-01

    The results of the research process of producing metalized products by solid-phase reduction of iron using solid carbonaceous reducing agents. Thermodynamic modeling was carried out on the model of the unit the Fe-C-O and system with iron ore and coal. As a result of modeling the thermodynamic boundary reducing, oxidizing, and transition areas and the value of the ratio of carbon and oxygen in the system. Simulation of real systems carried out with the gas phase obtained in the pyrolys of coal. The simulation results allow to determine the optimal cost of coal required for complete reduction of iron ore from a given composition. The kinetics of the processes of solid-phase reduction of iron using coal of various technological brands.

  15. Solid-Phase Synthesis of Amine/Carboxyl Substituted Prolines and Proline Homologues: Scope and Limitations.

    PubMed

    Zhou, Ziniu; Scott, William L; O'Donnell, Martin J

    2016-03-15

    A solid-phase procedure is used to synthesize racemic peptidomimetics based on the fundamental peptide unit. The peptidomimetics are constructed around proline or proline homologues variably substituted at the amine and carbonyl sites. The procedure expands the diversity of substituted peptidomimetic molecules available to the Distributed Drug Discovery (D3) project. Using a BAL-based solid-phase synthetic sequence the proline or proline homologue subunit is both constructed and incorporated into the peptidomimetic by an α-alkylation, hydrolysis and intramolecular cyclization sequence. Further transformations on solid-phase provide access to a variety of piperazine derivatives representing a class of molecules known to exhibit central nervous system activity. The procedure works well with proline cores, but with larger six- and seven-membered ring homologues the nature of the carboxylic acid acylating the cyclic amine can lead to side reactions and result in poor overall yields.

  16. A scheme for a single molecule phase-shift gate in a solid matrix

    SciTech Connect

    Cui, Xiao-Dong; Zheng, Yujun

    2015-06-07

    We propose a feasible scheme to implement a phase-shift gate ( (table) ) based on a two-state single molecule in a solid matrix, where γ is a geometric phase controlled through a fast on-resonant laser field and a slow off-resonant radio-frequency field. In our scheme, a non-Hermitian quantum model is employed to characterize the single molecule in a solid matrix including the spontaneous decay effect. By the coupling between the radio-frequency field and the two-state permanent dipole difference resulting from the solid matrix, the spontaneous decay fatal to the preservation of geometric phase can be effectively suppressed for a considerably long waiting time.

  17. Phase equilibria and stability characteristics of chlorpropamide-urea solid dispersions.

    PubMed

    Ford, J L; Rubinstein, M H

    1977-04-01

    Physical mixtures and melts of various compositions of chlorpropamide and urea have been prepared. The phase diagrams and the effects of ageing of the systems have been measured by differential scanning calorimetry. The eutectic composition was found to contain 89% w/w chlorpropamide. Greater concentrations of chlorpropamide produced solid solutions of urea in chlorpropamide, whereas solid solution formation did not occur at compositions less than 89%. Melts in the range 50-100% chlorpropamide, which included the eutectic, existed as glass solids. The effect of ageing produced generally an increase in the liquidus peak temperature which was considered to be due to a gradual increase in crystal size. PMID:17669

  18. NASA satellite communications application research. Phase 2: Efficient high power, solid state amplifier for EFH communications

    NASA Technical Reports Server (NTRS)

    Benet, James

    1993-01-01

    The final report describes the work performed from 9 Jun. 1992 to 31 Jul. 1993 on the NASA Satellite Communications Application Research (SCAR) Phase 2 program, Efficient High Power, Solid State Amplifier for EHF Communications. The purpose of the program was to demonstrate the feasibility of high-efficiency, high-power, EHF solid state amplifiers that are smaller, lighter, more efficient, and less costly than existing traveling wave tube (TWT) amplifiers by combining the output power from up to several hundred solid state amplifiers using a unique orthomode spatial power combiner (OSPC).

  19. Binary Solid-Liquid Phase Diagram of Phenol and t-Butanol: An Undergraduate Physical Chemistry Experiment

    ERIC Educational Resources Information Center

    Xu, Xinhua; Wang, Xiaogang; Wu, Meifen

    2014-01-01

    The determination of the solid-liquid phase diagram of a binary system is always used as an experiment in the undergraduate physical chemistry laboratory courses. However, most phase diagrams investigated in the lab are simple eutectic ones, despite the fact that complex binary solid-liquid phase diagrams are more common. In this article, the…

  20. Solid-phase synthetic route to multiple derivatives of a fundamental peptide unit.

    PubMed

    Scott, William L; Zhou, Ziniu; Zajdel, Paweł; Pawłowski, Maciej; O'Donnell, Martin J

    2010-07-20

    Amino acids are Nature's combinatorial building blocks. When substituted on both the amino and carboxyl sides they become the basic scaffold present in all peptides and proteins. We report a solid-phase synthetic route to large combinatorial variations of this fundamental scaffold, extending the variety of substituted biomimetic molecules available to successfully implement the Distributed Drug Discovery (D3) project. In a single solid-phase sequence, compatible with basic amine substituents, three-point variation is performed at the amino acid a-carbon and the amino and carboxyl functionalities.

  1. CuAAC: An Efficient Click Chemistry Reaction on Solid Phase.

    PubMed

    Castro, Vida; Rodríguez, Hortensia; Albericio, Fernando

    2016-01-11

    Click chemistry is an approach that uses efficient and reliable reactions, such as Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), to bind two molecular building blocks. CuAAC has broad applications in medicinal chemistry and other fields of chemistry. This review describes the general features and applications of CuAAC in solid-phase synthesis (CuAAC-SP), highlighting the suitability of this kind of reaction for peptides, nucleotides, small molecules, supramolecular structures, and polymers, among others. This versatile reaction is expected to become pivotal for meeting future challenges in solid-phase chemistry.

  2. Optical Measurement for Solid- and Liquid-Phase Sb2Te3 around Its Melting Point

    NASA Astrophysics Data System (ADS)

    Kuwahara, Masashi; Endo, Rie; Tsutsumi, Kouichi; Morikasa, Fukuyoshi; Tsuruoka, Tohru; Fukaya, Toshio; Suzuki, Michio; Susa, Masahiro; Endo, Tomoyoshi; Tadokoro, Toshiyasu

    2013-11-01

    We have developed a system for measuring the complex refractive index of liquid- and solid-phase chalcogenide around their melting points. The system consists of a spectroscopic ellipsometer, an infrared heating system, and prism optics. As a container for the chalcogenide, we use a customized quartz cell, evacuated to several pascal level to avoid sample degradation. We adopted a measurement configuration that uses access from the bottom side, because a mirror-like surface which is necessary for optical measurement was naturally and easily created at the container bottom by gravity. We succeeded in observing the remarkable difference on the indices between liquid- and solid-phase Sb2Te3.

  3. Solid-Phase Spectrophotometric Analysis of 1-Naphthol Using Silica Functionalized with m-Diazophenylarsonic Acid

    NASA Astrophysics Data System (ADS)

    Zaitseva, Nataliya; Alekseev, Sergei; Zaitsev, Vladimir; Raks, Viktoria

    2016-03-01

    The m-aminophenylarsonic acid (m-APAA) was immobilized onto the silica gel surface with covalently grafted quaternary ammonium groups via ion exchange. The diazotization of ion-bonded m-APAA resulted in a new solid-phase spectrophotometric reagent for detection of 1-naphtol in environmental water samples. The procedure of solid-phase spectrophotometric analysis is characterized by 20 μg L-1 limit of detection (LOD) of 1-naphtol, up to 2000 concentration factor, and insensitivity to the presence of natural water components as well as to 30-fold excess of phenol, resorcinol, and catechol.

  4. Application of solid phase extraction procedures for rare earth elements determination in environmental samples.

    PubMed

    Pyrzynska, Krystyna; Kubiak, Anna; Wysocka, Irena

    2016-07-01

    Determination of rare earth elements in environmental samples requires often pre-concentration and separation step due to a low metal content and high concentration of the interfering matrix components. A solid phase extraction technique with different kind of solid sorbents offers a high enrichment factor, rapid phase separation and the possibility of its combination with various detection techniques used either in on-line or off-line mode. The recent developments in this area published over the last five years are presented and discussed in this paper.

  5. Automated extraction of acetylgestagens from kidney fat by matrix solid phase dispersion.

    PubMed

    Rosén, J; Hellenäs, K E; Törnqvist, P; Shearan, P

    1994-12-01

    A new extraction method for the acetylgestagens medroxyprogesterone acetate (MPA), chloromadinone acetate and megestrol acetate, from kidney fat, has been developed. The method is a combination of matrix solid phase dispersion and solid phase extraction and is simpler and safer than previous methods, especially as it can be automated. The recovery was estimated as 59 +/- 5% (mean +/- standard deviation) for MPA. For screening purposes detection can be achieved using a commercially available enzyme immunoassay kit giving detection limits in the range of 1.0-2.0 ng g-1.

  6. Solid-phase trapping of solutes for further chromatographic or electrophoretic analysis.

    PubMed

    Frit, J S; Macka, M

    2000-12-01

    Because of its simplicity, speed and effectiveness, solid-phase extraction (SPE) has become the preferred technique for concentration of selected analytes prior to chromatographic or electrophoretic analysis. In this review the historical development of SPE is briefly traced. Then the principles of SPE are reviewed in some detail. Numerous references are given on the format, sorbents, elution conditions, online techniques and automation with special emphasis on relatively recent developments. The principles and recent advances in solid-phase microextraction (SPME) are also reviewed. The final section on selected recent applications includes an extensive list of references to work published within the last three years. Future trends and developments are discussed briefly.

  7. Use of the 2-chlorotrityl chloride resin for microwave-assisted solid phase peptide synthesis.

    PubMed

    Ieronymaki, Matthaia; Androutsou, Maria Eleni; Pantelia, Anna; Friligou, Irene; Crisp, Molly; High, Kirsty; Penkman, Kirsty; Gatos, Dimitrios; Tselios, Theodore

    2015-09-01

    A fast and efficient microwave (MW)-assisted solid-phase peptide synthesis protocol using the 2-chlorotrityl chloride resin and the Fmoc/tBu methodology, has been developed. The established protocol combines the advantages of MW irradiation and the acid labile 2-chlorotrityl chloride resin. The effect of temperature during the MW irradiation, the degree of resin substitution during the coupling of the first amino acids and the rate of racemization for each amino acid were evaluated. The suggested solid phase methodology is applicable for orthogonal peptide synthesis and for the synthesis of cyclic peptides. PMID:26270247

  8. Selective enrichment of phenols from coal liquefaction oil by solid phase extraction method

    SciTech Connect

    Tian, M.; Feng, J.

    2009-07-01

    This study focuses on the solid phase extraction method for the enrichment and separation of phenol from coal liquefaction oil. The phenols' separation efficiency was compared on different solid phase extraction (SPE) cartridges, and the effect of solvents with different polarity and solubility parameter on amino-bonded silica was compared for selection of optimal elution solution. The result showed that amino-bonded silica has the highest selectivity and best extraction capability due to two factors, weak anion exchange adsorption and polar attraction adsorption.

  9. Detection of ibuprofen and ciprofloxacin by solid-phase extraction and UV/Vis spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhou, Zhengwei; Jiang, Jia Qian

    2012-07-01

    A simple and economic solid-phase extraction coupled with UV/Vis spectrophotometric method is described for the analysis of ibuprofen and ciprofloxacin. Following solid-phase extraction from model wastewater samples containing standard ibuprofen or ciprofloxacin, elutes were analyzed by a UV/Vis spectrophotometer at 225 nm for ibuprofen and 280 nm for ciprofloxacin. The assay was linear for both compounds with good coefficients of correlation. This method shows good recoveries for both compounds with 101.0 ± 9.8% for ibuprofen and 99.4 ± 11.8% ciprofloxacin.

  10. Use of a solid phase red blood cell adherence method for pretransfusion platelet compatibility testing.

    PubMed

    Rachel, J M; Summers, T C; Sinor, L T; Plapp, F V

    1988-07-01

    A solid phase red blood cell adherence method has been used for platelet antibody detection and crossmatching for refractory platelet recipients. Patient sera were first screened for HLA or platelet-specific antibodies, then crossmatched with potential apheresis platelet donors. The overall correlation of platelet crossmatch results with transfusion outcome was 97% in patients with no evidence of nonimmune platelet destruction. The solid phase red blood cell adherence method provided a feasible and effective alternative to HLA matching as a means of donor selection for refractory platelet recipients. The speed and simplicity of this method may allow most hospital laboratories to perform platelet antibody screening before routine platelet transfusions.

  11. Reusable and specific proton transfer signalling by inorganic cyanide in solution and solid phase.

    PubMed

    Kaloo, Masood Ayoub; Sankar, Jeyaraman

    2015-10-01

    A highly specific cyanide mediated proton transfer signalling (PTS) is exhibited by a simple diaminomalenonitrile (DAMN) derivative 1. By virtue of the functional groups on it, the chromophore offered a rigid anchoring on a silica surface via a simple dip method, while retaining the recognition behaviour. The PTS triggered a prompt dual-modal display i.e., chromogenic and fluorogenic. The signal readout can be visualized even in micromolar concentrations. It is noteworthy that PTS can be reversed in both solution and solid phases. The remarkable sensitivity of 1 to detect CN(-) from the solution and solid phase envisages a pivotal step towards field-usable sensing.

  12. Sobrerol enantiomers and racemates: solid-state spectroscopy, thermal behavior, and phase diagrams.

    PubMed

    Bettinetti, G; Giordano, F; Fronza, G; Italia, A; Pellegata, R; Villa, M; Ventura, P

    1990-06-01

    The characterization of the solid state of sobrerol enantiomers and racemates has been accomplished by a number of techniques on solid phase such as thermal analysis (DSC) and spectroscopy (IR, 13C NMR, and X-ray diffraction both on powders and on single crystal). Experimental and theoretical binary phase diagrams of cis- and trans-sobrerol enantiomers and their mixtures have been drawn and are discussed. Thermal analysis allowed, moreover, the detection of cis racemate polymorphism. Finally, the quantitative analysis of the cis racemate as an impurity of the trans racemate by means of microcalorimetric determinations is reported.

  13. Liquid-phase extraction coupled with metal-organic frameworks-based dispersive solid phase extraction of herbicides in peanuts.

    PubMed

    Li, Na; Wang, Zhibing; Zhang, Liyuan; Nian, Li; Lei, Lei; Yang, Xiao; Zhang, Hanqi; Yu, Aimin

    2014-10-01

    Liquid-phase extraction coupled with metal-organic frameworks-based dispersive solid phase extraction was developed and applied to the extraction of pesticides in high fatty matrices. The herbicides were ultrasonically extracted from peanut using ethyl acetate as extraction solvent. The separation of the analytes from a large amount of co-extractive fat was achieved by dispersive solid-phase extraction using MIL-101(Cr) as sorbent. In this step, the analytes were adsorbed on MIL-101(Cr) and the fat remained in bulk. The herbicides were separated and determined by high-performance liquid chromatography. The experimental parameters, including type and volume of extraction solvent, ultrasonication time, volume of hexane and eluting solvent, amount of MIL-101(Cr) and dispersive solid phase extraction time, were optimized. The limits of detection for herbicides range from 0.98 to 1.9 μg/kg. The recoveries of the herbicides are in the range of 89.5-102.7% and relative standard deviations are equal or lower than 7.0%. The proposed method is simple, effective and suitable for treatment of the samples containing high content of fat.

  14. Effects of gravity reduction on phase equilibria. Part 1: Unary and binary isostructural solids

    NASA Technical Reports Server (NTRS)

    Larson, D. J., Jr.

    1975-01-01

    Analysis of the Skylab II M553 Experiment samples resulted in the hypothesis that the reduced gravity environment was altering the melting and solidification reactions. A theoretical study was conducted to define the conditions under which such alteration of phase relations is feasible, determine whether it is restricted to space processing, and, if so, ascertain which alloy systems or phase reactions are most likely to demonstrate such effects. Phase equilibria of unary and binary systems with a single solid phase (unary and isomorphous) were considered.

  15. Thermally stable coexistence of liquid and solid phases in gallium nanoparticles

    NASA Astrophysics Data System (ADS)

    Losurdo, Maria; Suvorova, Alexandra; Rubanov, Sergey; Hingerl, Kurt; Brown, April S.

    2016-09-01

    Gallium (Ga), a group III metal, is of fundamental interest due to its polymorphism and unusual phase transition behaviours. New solid phases have been observed when Ga is confined at the nanoscale. Herein, we demonstrate the stable coexistence, from 180 K to 800 K, of the unexpected solid γ-phase core and a liquid shell in substrate-supported Ga nanoparticles. We show that the support plays a fundamental role in determining Ga nanoparticle phases, with the driving forces for the nucleation of the γ-phase being the Laplace pressure in the nanoparticles and the epitaxial relationship of this phase to the substrate. We exploit the change in the amplitude of the evolving surface plasmon resonance of Ga nanoparticle ensembles during synthesis to reveal in real time the solid core formation in the liquid Ga nanoparticle. Finally, we provide a general framework for understanding how nanoscale confinement, interfacial and surface energies, and crystalline relationships to the substrate enable and stabilize the coexistence of unexpected phases.

  16. Thermally stable coexistence of liquid and solid phases in gallium nanoparticles.

    PubMed

    Losurdo, Maria; Suvorova, Alexandra; Rubanov, Sergey; Hingerl, Kurt; Brown, April S

    2016-09-01

    Gallium (Ga), a group III metal, is of fundamental interest due to its polymorphism and unusual phase transition behaviours. New solid phases have been observed when Ga is confined at the nanoscale. Herein, we demonstrate the stable coexistence, from 180 K to 800 K, of the unexpected solid γ-phase core and a liquid shell in substrate-supported Ga nanoparticles. We show that the support plays a fundamental role in determining Ga nanoparticle phases, with the driving forces for the nucleation of the γ-phase being the Laplace pressure in the nanoparticles and the epitaxial relationship of this phase to the substrate. We exploit the change in the amplitude of the evolving surface plasmon resonance of Ga nanoparticle ensembles during synthesis to reveal in real time the solid core formation in the liquid Ga nanoparticle. Finally, we provide a general framework for understanding how nanoscale confinement, interfacial and surface energies, and crystalline relationships to the substrate enable and stabilize the coexistence of unexpected phases. PMID:27454047

  17. Thermally stable coexistence of liquid and solid phases in gallium nanoparticles.

    PubMed

    Losurdo, Maria; Suvorova, Alexandra; Rubanov, Sergey; Hingerl, Kurt; Brown, April S

    2016-09-01

    Gallium (Ga), a group III metal, is of fundamental interest due to its polymorphism and unusual phase transition behaviours. New solid phases have been observed when Ga is confined at the nanoscale. Herein, we demonstrate the stable coexistence, from 180 K to 800 K, of the unexpected solid γ-phase core and a liquid shell in substrate-supported Ga nanoparticles. We show that the support plays a fundamental role in determining Ga nanoparticle phases, with the driving forces for the nucleation of the γ-phase being the Laplace pressure in the nanoparticles and the epitaxial relationship of this phase to the substrate. We exploit the change in the amplitude of the evolving surface plasmon resonance of Ga nanoparticle ensembles during synthesis to reveal in real time the solid core formation in the liquid Ga nanoparticle. Finally, we provide a general framework for understanding how nanoscale confinement, interfacial and surface energies, and crystalline relationships to the substrate enable and stabilize the coexistence of unexpected phases.

  18. Recent developments and future trends in solid phase microextraction techniques towards green analytical chemistry.

    PubMed

    Spietelun, Agata; Marcinkowski, Łukasz; de la Guardia, Miguel; Namieśnik, Jacek

    2013-12-20

    Solid phase microextraction find increasing applications in the sample preparation step before chromatographic determination of analytes in samples with a complex composition. These techniques allow for integrating several operations, such as sample collection, extraction, analyte enrichment above the detection limit of a given measuring instrument and the isolation of analytes from sample matrix. In this work the information about novel methodological and instrumental solutions in relation to different variants of solid phase extraction techniques, solid-phase microextraction (SPME), stir bar sorptive extraction (SBSE) and magnetic solid phase extraction (MSPE) is presented, including practical applications of these techniques and a critical discussion about their advantages and disadvantages. The proposed solutions fulfill the requirements resulting from the concept of sustainable development, and specifically from the implementation of green chemistry principles in analytical laboratories. Therefore, particular attention was paid to the description of possible uses of novel, selective stationary phases in extraction techniques, inter alia, polymeric ionic liquids, carbon nanotubes, and silica- and carbon-based sorbents. The methodological solutions, together with properly matched sampling devices for collecting analytes from samples with varying matrix composition, enable us to reduce the number of errors during the sample preparation prior to chromatographic analysis as well as to limit the negative impact of this analytical step on the natural environment and the health of laboratory employees. PMID:24238710

  19. Recent developments and future trends in solid phase microextraction techniques towards green analytical chemistry.

    PubMed

    Spietelun, Agata; Marcinkowski, Łukasz; de la Guardia, Miguel; Namieśnik, Jacek

    2013-12-20

    Solid phase microextraction find increasing applications in the sample preparation step before chromatographic determination of analytes in samples with a complex composition. These techniques allow for integrating several operations, such as sample collection, extraction, analyte enrichment above the detection limit of a given measuring instrument and the isolation of analytes from sample matrix. In this work the information about novel methodological and instrumental solutions in relation to different variants of solid phase extraction techniques, solid-phase microextraction (SPME), stir bar sorptive extraction (SBSE) and magnetic solid phase extraction (MSPE) is presented, including practical applications of these techniques and a critical discussion about their advantages and disadvantages. The proposed solutions fulfill the requirements resulting from the concept of sustainable development, and specifically from the implementation of green chemistry principles in analytical laboratories. Therefore, particular attention was paid to the description of possible uses of novel, selective stationary phases in extraction techniques, inter alia, polymeric ionic liquids, carbon nanotubes, and silica- and carbon-based sorbents. The methodological solutions, together with properly matched sampling devices for collecting analytes from samples with varying matrix composition, enable us to reduce the number of errors during the sample preparation prior to chromatographic analysis as well as to limit the negative impact of this analytical step on the natural environment and the health of laboratory employees.

  20. X-ray phase determination of solid paraffins in asphalts

    SciTech Connect

    Biktimirova, T.G.; Aleksandrova, S.L.; Fryazinov, V.V.

    1984-03-01

    This article discusses the attempt to increase the sensitivity of the x-ray phase analysis and to broaden the field of its application in determining the content of paraffins in petroleum asphalts and residual stocks from various raw materials. Samples were prepared by blending technical-grade paraffin wax with a paraffin-free asphalt. The influence of the cooling time on the intensity of the paraffin lines was determined for the various asphalt samples. In order to improve the reproducibility of the line intensity, 1% microcrystalline wax with a known content of paraffins was added to each reference sample. Artificial mixtures of paraffins with model asphalts having various group compositions were prepared in order to determine the influence of the composition of the various asphalts on the intensity of the paraffin reflections under the preparation conditions (heating and cooling). It is established that with increasing takeoff of distillate in the vacuum distillation of atmospheric resids, or in the course of oxidation of residual stocks to produce asphalts, the paraffin content drops. Includes 2 tables.

  1. Liquid versus solid phase bioassays for dredged material toxicity assessment.

    PubMed

    Casado-Martínez, M C; Fernández, N; Forja, J M; DelValls, T A

    2007-05-01

    Since 1994 the results of the analyses of key chemical compounds (trace metals, polychlorinated biphenyls and polycyclic aromatic hydrocarbons) and the comparison with the corresponding sediment quality guidelines (SQGs) are used in decision-making for dredged material management in Spain. Nonetheless in the last decades a tiered testing approach is promoted for assessing the physical and chemical characteristics of dredged sediments and their potential biological effects in the environment. Bioassays have been used for sediment toxicity assessment in Spain but few or no experiences are reported on harbour sediments. We studied the incidence of toxicity in the 7 d bioassay using rotifers (Brachionus plicatilis) and the 48 h bioassay using sea urchin (Paracentrotus lividus) embryos over a series of experiments employing 22 different elutriates. The relative performance of this exposure phase was not comparable to data on the 10-d acute toxicity test using the burrowing amphipod Corophium volutator and the polychaete Arenicola marina, carried out on the whole sediments. These results evidence the importance of the exposure route and the test selected in decision-making, as the toxicity registered for the undiluted elutriates was largely due to the different solubility of sediment-bound contaminants. This work and other studies indicate that for many sediments, a complete battery of test is recommended together with physico-chemical analyses to decide whether dredged sediments are suitable for open water disposal or not. PMID:17174396

  2. High-pressure chemistry of molecular solids: evidences for novel extended phases of carbon dioxide

    SciTech Connect

    Yoo, C S

    1999-07-22

    At high pressures and temperatures, many molecular solids become unstable and transform into denser extended phases. Recently, we have discovered evidences for two novel extended phases of carbon dioxide at high pressures and temperatures: (1) an ionic form of dimeric CO,, C02+C03*- at 8-13 GPa and above 2000 K [I] and (2) a polymeric phase CO,-V above 35 GPa and 1800 K [2,3]. These extended phases can be quenched at room temperature at low pressures, from which their molecular and crystal structures have been determined. These transitions occur to soften highly repulsive intermolecular potentials via delocalization of electrons at high pressures and temperatures. Based on these and other previous results, we conjecture that three fundamental mechanisms of high-pressure chemistry are ionization, polymerization, and metallization, occurring in high-density molecular solids and fluids. [carbon dioxide, polymeric COZ, ionic CO, dimer, high-pressure chemistry, electron delocalization

  3. Solid dispersion of pharmaceutical ternary systems I: Phase diagram of aspirin-acetaminophen-urea system.

    PubMed

    el-Banna, H M

    1978-08-01

    The phase diagram of an aspirin-acetaminophen-urea system was constructed. The data obtained by the thermomicroscopic method showed that the binary systems of aspirin-acetaminophen, aspirin-urea, and acetaminophen-urea are simple eutectic mixtures with negligible formation of solid solutions or molecular compounds. The equilateral triangular phase diagram of the ternary system revealed that it forms, upon solidification, solid dispersions of the mechanical mixture type. The ternary eutectic corresponded to a composition of 60% aspirin, 20% acetaminophen, and 20% urea at 72 degrees. The method of calculating the composition finally solidified melts, lying within any area of the phase diagram, is presented. Use of the phase diagram in selecting the optimum ratio of components to enhance dissolution rates of these drugs may be possible. PMID:671247

  4. Bioproduction of benzaldehyde in a solid-liquid two-phase partitioning bioreactor using Pichia pastoris.

    PubMed

    Jain, Ashu N; Khan, Tanya R; Daugulis, Andrew J

    2010-11-01

    The bioproduction of benzaldehyde from benzyl alcohol using Pichia pastoris was examined in a solid-liquid two-phase partitioning bioreactor (TPPB) to reduce substrate and product inhibition. Rational polymer selection identified Elvax 40W as an effective sequestering phase, possessing partition coefficients for benzyl alcohol and benzaldehyde of 3.5 and 35.4, respectively. The use of Elvax 40W increased the overall mass of benzaldehyde produced by approx. 300% in a 5 l bioreactor, relative to a single phase biotransformation. The two-phase system had a molar yield of 0.99, indicating that only minor losses occurred. These results provide a promising starting point for solid-liquid TPPBs to enhance benzaldehyde production, and suggest that multiple, targeted polymers may provide relief for transformations characterized by multiple inhibitory substrates/product/by-products.

  5. Structures of lithiated lysine and structural analogues in the gas phase: effects of water and proton affinity on zwitterionic stability.

    PubMed

    Lemoff, Andrew S; Bush, Matthew F; O'Brien, Jeremy T; Williams, Evan R

    2006-07-13

    The structures of lithiated lysine, ornithine, and related molecules, both with and without a water molecule, are investigated using both density functional theory and blackbody infrared radiative dissociation experiments. The lowest-energy structure of lithiated lysine without a water molecule is nonzwitterionic; the metal ion interacts with both nitrogen atoms and the carbonyl oxygen. Structures in which lysine is zwitterionic are higher in energy by more than 29 kJ/mol. In contrast, the singly hydrated clusters with the zwitterionic and nonzwitterionic forms of lysine are more similar in energy, with the nonzwitterionic form more stable by only approximately 7 kJ/mol. Thus, a single water molecule can substantially stabilize the zwitterionic form of an amino acid. Analogous molecules that have methyl groups attached to either the N-terminus (NMeLys) or the side-chain amine (Lys(Me)) have proton affinities greater than that of lysine. In the lithiated clusters with a water molecule attached, the zwitterionic forms of NMeLys and Lys(Me) are calculated to be approximately 4 and approximately 11 kJ/mol more stable than the nonzwitterionic forms, respectively. Calculations of the potential-energy pathway for interconversion between the different forms of lysine in the lithiated complex indicate multiple stable intermediates with an overall barrier height of approximately 83 kJ/mol between the lowest-energy nonzwitterionic form and the most accessible zwitterionic form. Experimentally determined binding energies of water are similar for all these complexes and range from 57 to 64 kJ/mol. These results suggest that loss of a water molecule from the lysine complexes is both energetically and entropically favored compared to interconversion between the nonzwitterionic and zwitterionic structures. Comparisons to calculated binding energies of water to the various structures show that the experimental results are most consistent with the nonzwitterionic forms. PMID

  6. Sensitive determination of plasma protein binding of cationic drugs using mixed-mode solid-phase microextraction.

    PubMed

    Peltenburg, Hester; Bosman, Ingrid J; Hermens, Joop L M

    2015-11-10

    Freely dissolved concentrations are considered to be the most relevant concentration in pharmacology and toxicology, as they represent the active concentration available for interaction with its surroundings. Here, a solid-phase microextraction (SPME) coating that combines octadecyl and propylsulfonic acid groups as strong cation exchange sites, known as C18/SCX or "mixed-mode" SPME, is used to measure freely dissolved concentrations of amitriptyline, amphetamine, diazepam and tramadol to different binding matrices, including bovine serum albumin (BSA), human serum albumin (HSA), human plasma and human whole blood. A potential confounding factor in binding studies is that proteins may sorb to the fiber coating leading to incorrect measurement of protein sorption or changes in uptake kinetics to the fiber coating. Sorption of bovine serum albumin (BSA) was observed and quantified using a Lowry assay. BSA binds to the C18/SCX fiber in small amounts, but large changes in uptake kinetics were not observed. All experiments were performed at equilibrium. In addition, however, the effect of depletion and non-equilibrium extraction on the estimation of protein binding affinities was also studied. Binding affinities to BSA and human serum albumin (HSA) were calculated as log KBSA or log KHSA. These values were very similar to reported literature values. Sampling at either equilibrium or non-equilibrium resulted in similar binding affinities. Furthermore, SPME fibers were used to measure freely dissolved concentrations in undiluted human plasma and whole blood. Analysis of SPME extracts could be performed using HPLC-UV or HPLC with fluorescence detection without prior clean-up of the samples. Measured bound fractions in plasma using this SPME approach were comparable to literature reference values. Bound fractions in whole blood were always higher than in plasma, due to red blood cell partitioning. This work shows the potential of SPME as sampling tool for freely dissolved

  7. Ionic liquid acceleration of solid-phase suzuki-miyaura cross-coupling reactions.

    PubMed

    Revell, Jefferson D; Ganesan, A

    2002-09-01

    [reaction: see text] Room-temperature ionic liquids promote various transition metal-catalyzed reactions in the solution phase. Here, for the first time, we show that these effects are translatable to solid-phase reactions. The Suzuki-Miyaura cross-coupling of 4-iodophenol immobilized on polystyrene-Wang resin with various arylboronic acids was significantly accelerated by the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF(4)(-)]).

  8. Solid-phase microextraction for the enantiomeric analysis of flavors in beverages.

    PubMed

    Ebeler, S E; Sun, G M; Datta, M; Stremple, P; Vickers, A K

    2001-01-01

    Solid-phase microextraction combined with gas chromatographic/mass spectrometric analysis and separation on a chiral cyclodextrin stationary phase was a rapid, reliable technique for profiling chiral aroma compounds in flavored alcoholic beverages. Several enantiomeric terpenes, esters, alcohols, norisoprenoids, and lactones were identified in berry-, peach-, strawberry-, and citrus-flavored wine and malt beverages (wine coolers). Using this technique, we were able to confirm the addition of synthetic flavoring to several beverages, consistent with label designations. PMID:11324614

  9. Direct molecular dynamics simulation of liquid-solid phase equilibria for a three-component plasma.

    PubMed

    Hughto, J; Horowitz, C J; Schneider, A S; Medin, Zach; Cumming, Andrew; Berry, D K

    2012-12-01

    The neutron-rich isotope ²²Ne may be a significant impurity in carbon and oxygen white dwarfs and could impact how the stars freeze. We perform molecular dynamics simulations to determine the influence of ²²Ne in carbon-oxygen-neon systems on liquid-solid phase equilibria. Both liquid and solid phases are present simultaneously in our simulation volumes. We identify liquid, solid, and interface regions in our simulations using a bond angle metric. In general we find good agreement for the composition of liquid and solid phases between our MD simulations and the semianalytic model of Medin and Cumming. The trace presence of a third component, neon, does not appear to strongly impact the chemical separation found previously for two-component carbon and oxygen systems. This suggests that small amounts of ²²Ne may not qualitatively change how the material in white dwarf stars freezes. However, we do find systematically lower melting temperatures (higher Γ) in our MD simulations compared to the semianalytic model. This difference seems to grow with impurity parameter Q_{imp} and suggests a problem with simple corrections to the linear mixing rule for the free energy of multicomponent solid mixtures that is used in the semianalytic model. PMID:23368065

  10. Direct molecular dynamics simulation of liquid-solid phase equilibria for a three-component plasma.

    PubMed

    Hughto, J; Horowitz, C J; Schneider, A S; Medin, Zach; Cumming, Andrew; Berry, D K

    2012-12-01

    The neutron-rich isotope ²²Ne may be a significant impurity in carbon and oxygen white dwarfs and could impact how the stars freeze. We perform molecular dynamics simulations to determine the influence of ²²Ne in carbon-oxygen-neon systems on liquid-solid phase equilibria. Both liquid and solid phases are present simultaneously in our simulation volumes. We identify liquid, solid, and interface regions in our simulations using a bond angle metric. In general we find good agreement for the composition of liquid and solid phases between our MD simulations and the semianalytic model of Medin and Cumming. The trace presence of a third component, neon, does not appear to strongly impact the chemical separation found previously for two-component carbon and oxygen systems. This suggests that small amounts of ²²Ne may not qualitatively change how the material in white dwarf stars freezes. However, we do find systematically lower melting temperatures (higher Γ) in our MD simulations compared to the semianalytic model. This difference seems to grow with impurity parameter Q_{imp} and suggests a problem with simple corrections to the linear mixing rule for the free energy of multicomponent solid mixtures that is used in the semianalytic model.

  11. Fluid-solid coexistence from two-phase simulations: binary colloidal mixtures and square well systems.

    PubMed

    Méndez-Maldonado, G Arlette; Chapela, Gustavo A; Martínez-González, José Adrián; Moreno, José Antonio; Díaz-Herrera, Enrique; Alejandre, José

    2015-02-01

    Molecular dynamics simulations are performed to clarify the reasons for the disagreement found in a previous publication [G. A. Chapela, F. del Río, and J. Alejandre, J. Chem. Phys. 138(5), 054507 (2013)] regarding the metastability of liquid-vapor coexistence on equimolar charged binary mixtures of fluids interacting with a soft Yukawa potential with κσ = 6. The fluid-solid separation obtained with the two-phase simulation method is found to be in agreement with previous works based on free energy calculations [A. Fortini, A.-P. Hynninen, and M. Dijkstra, J. Chem. Phys. 125, 094502 (2006)] only when the CsCl structure of the solid is used. It is shown that when pressure is increased at constant temperature, the solids are amorphous having different structures, densities, and the diagonal components of the pressure tensor are not equal. A stable low density fluid-solid phase separation is not observed for temperatures above the liquid-vapor critical point. In addition, Monte Carlo and discontinuous molecular dynamics simulations are performed on the square well model of range 1.15σ. A stable fluid-solid transition is observed above the vapor-liquid critical temperature only when the solid has a face centered cubic crystalline structure.

  12. Direct molecular dynamics simulation of liquid-solid phase equilibria for two-component plasmas.

    PubMed

    Schneider, A S; Hughto, J; Horowitz, C J; Berry, D K

    2012-06-01

    We determine the liquid-solid phase diagram for carbon-oxygen and oxygen-selenium plasma mixtures using two-phase molecular dynamics simulations. We identify liquid, solid, and interface regions using a bond angle metric. To study finite-size effects, we perform 27,648- and 55,296-ion simulations. To help monitor nonequilibrium effects, we calculate diffusion constants D(i). For the carbon-oxygen system we find that D(O) for oxygen ions in the solid is much smaller than D(C) for carbon ions and that both diffusion constants are 80 or more times smaller than diffusion constants in the liquid phase. There is excellent agreement between our carbon-oxygen phase diagram and that predicted by Medin and Cumming. This suggests that errors from finite-size and nonequilibrium effects are small and that the carbon-oxygen phase diagram is now accurately known. The oxygen-selenium system is a simple two-component model for more complex rapid proton capture nucleosynthesis ash compositions for an accreting neutron star. Diffusion of oxygen, in a predominantly selenium crystal, is remarkably fast, comparable to diffusion in the liquid phase. We find a somewhat lower melting temperature for the oxygen-selenium system than that predicted by Medin and Cumming. This is probably because of electron screening effects. PMID:23005226

  13. Dynamically slow solid-to-solid phase transition induced by thermal treatment of DimimFeCl4 magnetic ionic liquid.

    PubMed

    de Pedro, Imanol; Fabelo, Oscar; García-Saiz, Abel; Vallcorba, Oriol; Junquera, Javier; Blanco, Jesús Angel; Waerenborgh, João Carlos; Andreica, D; Wildes, Andrew; Fernández-Díaz, María Teresa; Fernández, Jesús Rodríguez

    2016-08-01

    The results reported here represent the first direct experimental observations supporting the existence of a solid-to-solid phase transition induced by thermal treatment in magnetic ionic liquids (MILs). The phase transitions of the solid phases of 1,3-dimethylimidazolium tetrachloroferrate, DimimFeCl4, are closely related to its thermal history. Two series of solid-to-solid phase transitions can be described in this MIL: (i) from room temperature (RT) phase II [space group (s.g.) = P21] to phase I-a [s.g. = P212121] via thermal quenching or via fast cooling at T > 2 K min(-1); (ii) from phase I-a to phase I-b [s.g. = P21/c] when the temperature was kept above 180 K for several minutes. The latter involves a slow translational and reorientational dynamical process of both the imidazolium cation and the tetrachloroferrate anion and has been characterized using synchrotron and neutron powder diffraction and DFT (density functional theory) studies. The transition is also related to the modification of the super-exchange pathways of low-temperature phases which show a overall antiferromagnetic behavior. A combination of several experimental methods such as magnetometry, Mössbauer and muon spectroscopy together with polarized and non-polarized neutron powder diffraction has been used in order to characterize the different features observed in these phases. PMID:27439896

  14. Use of itaconic acid-based polymers for solid-phase extraction of deoxynivalenol and application to pasta analysis.

    PubMed

    Pascale, Michelangelo; De Girolamo, Annalisa; Visconti, Angelo; Magan, Naresh; Chianella, Iva; Piletska, Elena V; Piletsky, Sergey A

    2008-02-25

    Molecular modelling and computational design were used to identify itaconic acid (IA) as a functional monomer with high affinity towards deoxynivalenol (DON), a Fusarium-toxin frequently occurring in cereals. IA-based polymers were photochemically synthesised in dimethyl formamide (porogen) using ethylenglycol dimethacrylate as cross-linker and 1,1'-azo-bis(cyclohexane carbonitrile) as initiator, and the relevant binding interactions with DON in solvents with different polarity were investigated. The performances of the non-imprinted IA-based polymer (blank polymer, BP) and the corresponding molecularly imprinted polymer (MIP) were compared using DON as a template. Both BP and MIP were able to bind about 90% DON either in toluene, water or water containing 5% polyethylene glycol. Non-imprinted polymers with different molar ratios of IA to cross-linker were evaluated as adsorbents for solid-phase extraction (SPE) clean-up and pre-concentration of DON from wheat and pasta samples prior to HPLC analysis. Samples were extracted with PBS/0.1M EDTA solution and cleaned up through a cartridge containing blank IA-based polymer. The column was washed with PBS (pH 9.2) and the toxin was eluted with methanol and quantified by reversed-phase HPLC with UV detector (lambda=220nm), using methanol:water:acetic acid (15:85:0.1, v/v/v) as the mobile phase. Effective removal of matrix interferences was observed only for pasta with DON recoveries higher than 70% (RSD<7%, n=3) at levels close to or higher than EU regulatory limit.

  15. Polydopamine supported preparation method for solid-phase microextraction coatings on stainless steel wire.

    PubMed

    Feng, Juanjuan; Sun, Min; Li, Jubai; Xu, Lili; Liu, Xia; Jiang, Shengxiang

    2011-06-10

    In this paper, we introduced a novel and versatile route to prepare solid-phase microextraction coatings on the chemically inert stainless steel wire. Polydopamine films can be created on metallic substrates by an oxidant-induced polymerization and subsequently support various secondary reactions to prepare functional surfaces. In the present work, polydopamine-bioactivated stainless steel wire was successfully modified by nanostructured hydroxyapatite. Extraction performance of the fiber was assessed on several polycyclic aromatic hydrocarbons in water solutions. Extraction mechanism was suggested based on the correlation of partition coefficients and LogPs. Both aqueous and solid real life samples were used to test the reliability of the solid-phase microextraction-gas chromatography method; some analytes were detected and quantified.

  16. The synthesis and chemical durability of Nd-doped single-phase zirconolite solid solutions

    NASA Astrophysics Data System (ADS)

    Cai, Xin; Teng, Yuancheng; Wu, Lang; Zhang, Kuibao; Huang, Yi

    2016-10-01

    Nd-doped single-phase zirconolite solid solutions was synthesized by solid-state reaction and following two steps of acid treatment. The phase composition, microstructure, and chemical durability of the zirconolite solid solutions were investigated. About 15 at% Nd was successfully stabilized into the zirconolite. The element mapping images of Ca, Zr, Nd and Ti show that all the elements are almost distributed homogeneously in the zirconolite waste forms. Product Consistency Test (PCT) was conducted under different pH values (pH = 5, 7 and 9) to evaluate the chemical durability of the Nd-doped zirconolite waste forms. The normalized element release rate of Ca (LRCa) in pH = 5 medium is higher than that of pH = 7 and 9, while the LRNd value remains almost unchanged under different pH values. The LRNd value is as low as 10-5 g m-2 d-1 after 42 days.

  17. Advances in automatic, manual and microwave-assisted solid-phase peptide synthesis.

    PubMed

    Sabatino, Giuseppina; Papini, Anna M

    2008-11-01

    Solid-phase strategies speed up the production of both short- and long-sequence peptides compared with solution methodologies. Therefore, solid-phase peptide synthesis (SPPS), proposed by Merrifield in the early 1960s, contributed to the 'Peptide Revolution' in the fields of diagnostics, and drug and vaccine development. Since then, peptide chemistry research has aimed to optimize these synthetic procedures, focusing on areas such as amide bond formation (the coupling step), solid supports and automation. Particular attention was devoted to the environmental impact of SPPS: the requirement for large amounts of organic solvents meant high costs for industrial peptide manufacturing that needed to be reduced. SPPS, alone or in hybrid technologies, has become strategic for the production of peptides as active pharmaceutical ingredients on a commercial scale.

  18. Development of a Solid Phase Extraction Method for Agricultural Pesticides in Large-Volume Water Samples

    EPA Science Inventory

    An analytical method using solid phase extraction (SPE) and analysis by gas chromatography/mass spectrometry (GC/MS) was developed for the trace determination of a variety of agricultural pesticides and selected transformation products in large-volume high-elevation lake water sa...

  19. Solid-phase microextraction of hydrocarbons from water in a centrifuge

    NASA Astrophysics Data System (ADS)

    Ryabov, A. Yu.; Chuikin, A. V.; Velikov, A. A.

    2016-06-01

    The results of our study of solid-phase microextraction of substances using a centrifuge for determining the microquantities of hydrocarbon impurities in water are presented. The cartridge diameter, sorbent mass, and solvent volume were shown to affect the percent extraction of substances and the analytical signal intensity. The relationship between the cartridge geometry, the sorbent mass, and the solvent volume was considered.

  20. A Discovery-Oriented Approach to Solid-Phase Peptide Synthesis

    ERIC Educational Resources Information Center

    Bockman, Matthew R.; Miedema, Christopher J.; Brennan, Brian B.

    2012-01-01

    In this discovery-oriented laboratory experiment, students use solid-phase synthesis techniques to construct a dipeptide containing an unknown amino acid. Following synthesis and cleavage from the polymeric support, electrospray ionization-mass spectrometry is employed to identify the unknown amino acid that was used in the peptide coupling. This…

  1. Determination of Plant Volatiles Using Solid Phase Microextraction GC-MS

    ERIC Educational Resources Information Center

    Van Bramer, Scott; Goodrich, Katherine R.

    2015-01-01

    This experiment combines analytical techniques of solid phase microextraction and gas chromatography-mass spectrometry with easily relatable and accessible plant volatile chemistry (floral and vegetative scents of local/available plants). The biosynthesis and structure of these chemicals are of interest in the areas of organic chemistry,…

  2. Effects of inoculum size on solid-phase fermentation of fodder beets for fuel ethanol production

    SciTech Connect

    Gibbons, W.R.; Westby, C.A.

    1986-10-01

    This fuel ethanol study examined the effects of Saccharomyces cerevisiae inoculum size on solid-phase fermentation of fodder beet pulp. A 5% inoculum (wt/wt) resulted in rapid yeast and ethanol (9.1% (vol/vol)) production. Higher inocula showed no advantages. Lower inocula resulted in lowered final yeast populations and increased fermentation times.

  3. COMPARISON OF TWO DIFFERENT SOLID PHASE EXTRACTION/LARGE VOLUME INJECTION PROCEDURES FOR METHOD 8270

    EPA Science Inventory

    Two solid phase (SPE) and one traditional continuous liquid-liquid extraction method are compared for analysis of Method 8270 SVOCs. Productivity parameters include data quality, sample volume, analysis time and solvent waste.

    One SPE system, unique in the U.S., uses aut...

  4. Use of Solid Phase Extraction in the Biochemistry Laboratory to Separate Different Lipids

    ERIC Educational Resources Information Center

    Flurkey, William H.

    2005-01-01

    Solid-phase extraction (SPE) was used to demonstrate how various lipids and lipid classes could be separated in a biochemistry laboratory setting. Three different SPE methods were chosen on their ability to separate a lipid mixture, consisting of a combination of a either a fatty acid, a triacylglycerol, a mono- or diacylglycerol, phospholipid,…

  5. THE DISTRIBUTION AND SOLID-PHASE SPECIATION OF AS IN IRON-BASED TREATMENT MEDIA

    EPA Science Inventory

    Arsenic concentrations (Total Recoverable As by EPA Method 3051) and solid-phase speciation (by X-ray Absorption Near-Edge Spectroscopy-XANES) were assessed as a function of depth through Fe-media beds for two commercially available products from pilot-scale field tests. These r...

  6. Final Report for Nucleation and growth of semiconductor nanocrystals by solid-phase reaction

    SciTech Connect

    P. D. Persans; T. M. Hayes

    2005-12-12

    This final report describes the technical output of a scientific program aimed at understanding the formation and structure of II-VI nanocrystals formed by solid phase precipitation within a glass environment. The principle probes were optical absorption spectroscopy to determine crystallite sizes, Raman scattering to determine composition, and x-ray absorption spectroscopy to study the evolution of local reactant environments.

  7. Thermal battery. [solid metal halide electrolytes with enhanced electrical conductance after a phase transition

    DOEpatents

    Carlsten, R.W.; Nissen, D.A.

    1973-03-06

    The patent describes an improved thermal battery whose novel design eliminates various disadvantages of previous such devices. Its major features include a halide cathode, a solid metal halide electrolyte which has a substantially greater electrical conductance after a phase transition at some temperature, and a means for heating its electrochemical cells to activation temperature.

  8. Micro versus macro solid phase extraction for monitoring water contaminants: a preliminary study using trihalomethanes.

    PubMed

    Alexandrou, Lydon D; Spencer, Michelle J S; Morrison, Paul D; Meehan, Barry J; Jones, Oliver A H

    2015-04-15

    Solid phase extraction is one of the most commonly used pre-concentration and cleanup steps in environmental science. However, traditional methods need electrically powered pumps, can use large volumes of solvent (if multiple samples are run), and require several hours to filter a sample. Additionally, if the cartridge is open to the air volatile compounds may be lost and sample integrity compromised. In contrast, micro cartridge based solid phase extraction can be completed in less than 2 min by hand, uses only microlitres of solvent and provides comparable concentration factors to established methods. It is also an enclosed system so volatile components are not lost. The sample can also be eluted directly into a detector (e.g. a mass spectrometer) if required. However, the technology is new and has not been much used for environmental analysis. In this study we compare traditional (macro) and the new micro solid phase extraction for the analysis of four common volatile trihalomethanes (trichloromethane, bromodichloromethane, dibromochloromethane and tribromomethane). The results demonstrate that micro solid phase extraction is faster and cheaper than traditional methods with similar recovery rates for the target compounds. This method shows potential for further development in a range of applications.

  9. SOLID PHASE MICROEXTRACTION FOR TRACE LEVEL ANALYSIS OF DISINFECTION BY-PRODUCTS

    EPA Science Inventory

    This presentation focuses on the development of a solid-phase microextraction (SPME)-gas chromatography (GC)/ion trap mass spectrometry (MS) method for the analysis of semivolatile disinfection by-products (DBPs) in drinking water in the low ug/L range. These DBPs were selected ...

  10. Efficient solid phase strategy for preparation of modified xanthene dyes for biolabelling.

    PubMed

    Cardenas-Maestre, Juan M; Sanchez-Martin, Rosario M

    2011-03-21

    An efficient solid phase strategy for the versatile functionalisation of xanthene dyes for conjugation and labelling of biomolecules is presented. The low cost, high purity and excellent spectral properties of the obtained materials provide an attractive alternative for the labelling of a wide range of molecules.

  11. Deglycobleomycin: solid-phase synthesis and DNA cleavage by the resin-bound ligand.

    PubMed

    Smith, Kenneth L; Tao, Zhi-Fu; Hashimoto, Shigeki; Leitheiser, Christopher J; Wu, Xihan; Hecht, Sidney M

    2002-04-01

    [structure: see text] A greatly improved solid-phase synthesis of deglycobleomycin using a Dde-based linker is reported. The resin-bound deglycobleomycin could be completely deblocked and assayed for DNA plasmid relaxation, sequence-selective DNA cleavage, and light production from a molecular beacon.

  12. Influence of Calcium on Microbial Reduction of Solid Phase Uranium (VI)

    SciTech Connect

    Liu, Chongxuan; Jeon, Byong-Hun; Zachara, John M.; Wang, Zheming

    2007-06-27

    The effect of calcium on microbial reduction of a solid phase U(VI), sodium boltwoodite (NaUO2SiO3OH ∙1.5H2O), was evaluated in a culture of a dissimilatory metal-reducing bacterium (DMRB), Shewanella oneidensis strain MR-1. Batch experiments were performed in a non-growth bicarbonate medium with lactate as electron donor at pH 7 buffered with PIPES. Calcium increased both the rate and extent of Na-boltwoodite dissolution by increasing its solubility through the formation of a ternary aqueous calcium-uranyl-carbonate species. The ternary species, however, decreased the rates of microbial reduction of aqueous U(VI). Laser-induced fluorescence spectroscopy (LIFS) and transmission electron microscopy (TEM) revealed that microbial reduction of solid phase U(VI) is a sequentially coupled process of Na-boltwoodite dissolution, U(VI) aqueous speciation, and microbial reduction of dissolved U(VI) to U(IV) that accumulated on bacterial surfaces/periplasm. The overall rates of microbial reduction of solid phase U(VI) can be described by the coupled rates of dissolution and microbial reduction that were both influenced by calcium. The results demonstrated that dissolved U(VI) concentration during microbial reduction was a complex function of solid phase U(VI) dissolution kinetics, aqueous U(VI) speciation, and microbial activity.

  13. Solid-gaseous phase transformation of elemental contaminants during the gasification of biomass.

    PubMed

    Jiang, Ying; Ameh, Abiba; Lei, Mei; Duan, Lunbo; Longhurst, Philip

    2016-09-01

    Disposal of plant biomass removed from heavy metal contaminated land via gasification achieves significant volume reduction and can recover energy. However, these biomass often contain high concentrations of heavy metals leading to hot-corrosion of gasification facilities and toxic gaseous emissions. Therefore, it is of significant interest to gain a further understanding of the solid-gas phase transition of metal(loid)s during gasification. Detailed elemental analyses (C, H, O, N and key metal/metalloid elements) were performed on five plant species collected from a contaminated site. Using multi-phase equilibria modelling software (MTDATA), the analytical data allows modelling of the solid/gas transformation of metal(loid)s during gasification. Thermodynamic modelling based on chemical equilibrium calculations was carried out in this study to predict the fate of metal(loid) elements during typical gasification conditions and to show how these are influenced by metal(loid) composition in the biomass and operational conditions. As, Cd, Zn and Pb tend to transform to their gaseous forms at relatively low temperatures (<1000°C). Ni, Cu, Mn and Co converts to gaseous forms within the typical gasification temperature range of 1000-1200°C. Whereas Cr, Al, Fe and Mg remain in solid phase at higher temperatures (>1200°C). Simulation of pressurised gasification conditions shows that higher pressures increase the temperature at which solid-to-gaseous phase transformations takes place. PMID:26603198

  14. AUTOMATED SOLID PHASE EXTRACTION GC/MS FOR ANALYSIS OF SEMIVOLATILES IN WATER AND SEDIMENTS

    EPA Science Inventory

    Data is presented on the development of a new automated system combining solid phase extraction (SPE) with GC/MS spectrometry for the single-run analysis of water samples containing a broad range of organic compounds. The system uses commercially available automated in-line sampl...

  15. Solid-gaseous phase transformation of elemental contaminants during the gasification of biomass.

    PubMed

    Jiang, Ying; Ameh, Abiba; Lei, Mei; Duan, Lunbo; Longhurst, Philip

    2016-09-01

    Disposal of plant biomass removed from heavy metal contaminated land via gasification achieves significant volume reduction and can recover energy. However, these biomass often contain high concentrations of heavy metals leading to hot-corrosion of gasification facilities and toxic gaseous emissions. Therefore, it is of significant interest to gain a further understanding of the solid-gas phase transition of metal(loid)s during gasification. Detailed elemental analyses (C, H, O, N and key metal/metalloid elements) were performed on five plant species collected from a contaminated site. Using multi-phase equilibria modelling software (MTDATA), the analytical data allows modelling of the solid/gas transformation of metal(loid)s during gasification. Thermodynamic modelling based on chemical equilibrium calculations was carried out in this study to predict the fate of metal(loid) elements during typical gasification conditions and to show how these are influenced by metal(loid) composition in the biomass and operational conditions. As, Cd, Zn and Pb tend to transform to their gaseous forms at relatively low temperatures (<1000°C). Ni, Cu, Mn and Co converts to gaseous forms within the typical gasification temperature range of 1000-1200°C. Whereas Cr, Al, Fe and Mg remain in solid phase at higher temperatures (>1200°C). Simulation of pressurised gasification conditions shows that higher pressures increase the temperature at which solid-to-gaseous phase transformations takes place.

  16. Investigating the Retention Mechanisms of Liquid Chromatography Using Solid-Phase Extraction Cartridges

    ERIC Educational Resources Information Center

    O'Donnell, Mary E.; Musial, Beata A.; Bretz, Stacey Lowery; Danielson, Neil D.; Ca, Diep

    2009-01-01

    Liquid chromatography (LC) experiments for the undergraduate analytical laboratory course often illustrate the application of reversed-phase LC to solve a separation problem, but rarely compare LC retention mechanisms. In addition, a high-performance liquid chromatography instrument may be beyond what some small colleges can purchase. Solid-phase…

  17. Soxhlet-assisted matrix solid phase dispersion to extract flavonoids from rape (Brassica campestris) bee pollen.

    PubMed

    Ma, Shuangqin; Tu, Xijuan; Dong, Jiangtao; Long, Peng; Yang, Wenchao; Miao, Xiaoqing; Chen, Wenbin; Wu, Zhenhong

    2015-11-15

    Soxhlet-assisted matrix solid phase dispersion (SA-MSPD) method was developed to extract flavonoids from rape (Brassica campestris) bee pollen. Extraction parameters including the extraction solvent, the extraction time, and the solid support conditions were investigated and optimized. The best extraction yields were obtained using ethanol as the extraction solvent, silica gel as the solid support with 1:2 samples to solid support ratio, and the extraction time of one hour. Comparing with the conventional solvent extraction and Soxhlet method, our results show that SA-MSPD method is a more effective technique with clean-up ability. In the test of six different samples of rape bee pollen, the extracted content of flavonoids was close to 10mg/g. The present work provided a simple and effective method for extracting flavonoids from rape bee pollen, and it could be applied in the studies of other kinds of bee pollen.

  18. Determination of aflatoxins in rice samples by ultrasound-assisted matrix solid-phase dispersion.

    PubMed

    Manoochehri, Mahboobeh; Asgharinezhad, Ali Akbar; Safaei, Mahdi

    2015-01-01

    This work describes the application of ultrasound-assisted matrix solid-phase dispersion as an extraction and sample preparation approach for aflatoxins (B1, B2, G1 and G2) and subsequent determination of them by high-performance liquid chromatography-fluorescence detection. A Box-Behnken design in combination with response surface methodology was used to determine the affecting parameters on the extraction procedure. The influence of different variables including type of dispersing phase, sample-to-dispersing phase ratio, type and quantity of clean-up phase, ultrasonication time, ultrasonication temperature, nature and volume of the elution solvent was investigated in the optimization study. C18, primary-secondary amine (PSA) and acetonitrile were selected as dispersing phase, clean-up phase and elution solvent, respectively. The obtained optimized values were sample-to-dispersing phase ratio of 1 : 1, 60 mg of PSA, 11 min ultrasonication time, 30°C ultrasonication temperature and 4 mL acetonitrile. Under the optimal conditions, the limits of detection were ranged from 0.09 to 0.14 ng g(-1) and the precisions [relative standard deviation (RSD%)] were <8.6%. The recoveries of the matrix solid-phase dispersion process ranged from 78 to 83% with RSD <10% in all cases. Finally, this method was successfully applied to the extraction of trace amounts of aflatoxins in rice samples.

  19. Aqueous- and solid-phase biogeochemistry of a calcareous aquifer system downgradient from a municipal solid waste landfill (Winterthur, Switzerland)

    SciTech Connect

    Amirbahman, A.; Schoenenberger, R.; Johnson, C.A.; Sigg, L. |

    1998-07-01

    This study addresses the biogeochemical changes that take place in a calcareous aquifer system under and down-gradient from a municipal solid waste landfill. Aqueous-phase chemical analysis of the redox-sensitive species indicates the presence of aerobic respiration, denitrification/NO{sub 3}{sup {minus}} reduction, and Fe(III), Mn(III/IV), and SO{sub 4} reduction processes under the landfill. Because available and released organic matter is limited, reduction processes downgradient from the landfill do not go far beyond aerobic respiration, denitrification, and Mn(III/IV) reduction. Assuming steady-state conditions, STEADYQL computer program has been used to model the biogeochemical processes by taking into account the kinetics of the redox reactions, calcite precipitation and dilution. Dilution has the most significant influence on the concentrations of the dissolved organic and inorganic carbon. Dissolved Mn(II) concentrations in the entire anaerobic zone are controlled by the solubility of rhodocrocite [MnCO{sub 3}(S)]. At selected locations under the landfill where SO{sub 4} reduction takes place, dissolved Fe(II) concentrations are regulated by the solubility of amorphous FeS. Chemical extraction of the aquifer solid phase indicates that the oxidation capacity of this aquifer system is largely controlled by iron(III)(hydr)-oxides.

  20. A phase-field approach to nonequilibrium phase transformations in elastic solids via an intermediate phase (melt) allowing for interface stresses.

    PubMed

    Momeni, Kasra; Levitas, Valery I

    2016-04-28

    A phase-field approach for phase transformations (PTs) between three different phases at nonequilibrium temperatures is developed. It includes advanced mechanics, thermodynamically consistent interfacial stresses, and interface interactions. A thermodynamic Landau-Ginzburg potential developed in terms of polar order parameters satisfies the desired instability and equilibrium conditions for homogeneous phases. The interfacial stresses were introduced with some terms from large-strain formulation even though the small-strain assumption was utilized. The developed model is applied to study the PTs between two solid phases via a highly disordered intermediate phase (IP) or an intermediate melt (IM) hundreds of degrees below the melting temperature. In particular, the β ↔ δ PTs in HMX energetic crystals via IM are analyzed. The effects of various parameters (temperature, ratios of widths and energies of solid-solid (SS) to solid-melt (SM) interfaces, elastic energy, and interfacial stresses) on the formation, stability, and structure of the IM within a propagating SS interface are studied. Interfacial and elastic stresses within a SS interphase and their relaxation and redistribution with the appearance of a partial or complete IM are analyzed. The energy and structure of the critical nucleus (CN) of the IM are studied as well. In particular, the interfacial stresses increase the aspect-ratio of the CN. Although including elastic energy can drastically reduce the energy of the CN of the IM, the activation energy of the CN of the IM within the SS interface increases when interfacial tension is taken into account. The developed thermodynamic potential can also be modified to model other multiphase physical phenomena, such as multi-variant martensitic PTs, grain boundary and surface-induced pre-melting and PTs, as well as developing phase diagrams for IPs.

  1. Free energy model for solid high-pressure phases of carbon.

    PubMed

    Schöttler, Manuel; French, Martin; Cebulla, Daniel; Redmer, Ronald

    2016-04-13

    Analytic free energy models for three solid high-pressure phases--diamond, body centered cubic phase with eight atoms in the unit cell (BC8), and simple cubic (SC)--are developed using density functional theory. We explicitly include anharmonic effects by performing molecular dynamics simulations and investigate their density and temperature dependence in detail. Anharmonicity in the nuclear motion shifts the phase transitions significantly compared to the harmonic approximation. Furthermore, we apply a thermodynamically constrained correction that brings the equation of state in accordance with diamond anvil cell experiments. The performance of our thermodynamic functions is validated against Hugoniot experiments. PMID:26974530

  2. Preparation and characteristics of new coating for solid-phase microextraction.

    PubMed

    Yang, Min; Wang, Yi-long; Zeng, Zhao-rui; Zhou, Ying

    2002-05-01

    Poly (methylphenylvinylsiloxane) (PMPVS) coating for solid-phase microextraction (SPME) was first prepared by using sol-gel approach and cross-linking of free radical initiation. The extraction properties of the novel coating for aromatic compounds were investigated using a self-made SPME device coupled with a gas chromatograph-flame ionization detector (GC-FID). The coating provided high surface areas and allowed high extraction efficiency. Compared with some commercial SPME stationary phases, the new phase showed better selectivity and sensitivity toward aromatic compounds. Furthermore, PMPVS coating showed good thermal stability and longer lifetime. PMID:12541936

  3. Solid solubility, phase transitions, thermal expansion, and compressibility in Sc1-xAlxF3

    NASA Astrophysics Data System (ADS)

    Morelock, Cody R.; Gallington, Leighanne C.; Wilkinson, Angus P.

    2015-02-01

    With the goal of thermal expansion control, the synthesis and properties of Sc1-xAlxF3 were investigated. The solubility limit of AlF3 in ScF3 at ~1340 K is ~50%. Solid solutions (x≤0.50) were characterized by synchrotron powder diffraction at ambient pressure between 100 and 900 K and at pressures <0.414 GPa while heating from 298 to 523 K. A phase transition from cubic to rhombohedral is observed. The transition temperature increases smoothly with Al3+ content, approaching 500 K at the solid solubility limit, and also upon compression at fixed Al3+ content. The slope of the pressure-temperature phase boundary is ~0.5 K MPa-1, which is steep relative to that for most symmetry-lowering phase transitions in perovskites. The volume coefficient of thermal expansion (CTE) for the rhombohedral phase is strongly positive, but the cubic-phase CTE varies from negative (x<0.15) to near-zero (x=0.15) to positive (x>0.20) between ~600 and 800 K. The cubic solid solutions elastically stiffen on heating, while Al3+ substitution causes softening at a given temperature.

  4. Fourier transform infrared study of a phase transition in solid chlorodifluoromethane

    NASA Astrophysics Data System (ADS)

    Anderson, A.; Beardsall, A. J.; Fraser, Jim

    1994-01-01

    Infrared spectra of solid chlorodifluoromethane (CHClF2 or Freon 22) at temperatures between 12 K and 105 K have been recorded. Both lattice and internal mode regions have been investigated by utilizing two Fourier transform spectrometers, one for the far-infrared region (20 - 400 cm-1) and the other for the mid-infrared region (400 - 4000 cm-1). Evidence for a solid state phase transition at 55 +/- 5 K is presented. Multiplet structure for the nine internal modes is observed over a wide range of temperature and in most cases is shown to result from crystal field rather than isotopic or other effects. This indicates that both phases are ordered with rather large unit cells, and that the phase transition is therefore of a displacive type.

  5. Accelerated exploration of multi-principal element alloys with solid solution phases

    PubMed Central

    Senkov, O.N.; Miller, J.D.; Miracle, D.B.; Woodward, C.

    2015-01-01

    Recent multi-principal element, high entropy alloy (HEA) development strategies vastly expand the number of candidate alloy systems, but also pose a new challenge—how to rapidly screen thousands of candidate alloy systems for targeted properties. Here we develop a new approach to rapidly assess structural metals by combining calculated phase diagrams with simple rules based on the phases present, their transformation temperatures and useful microstructures. We evaluate over 130,000 alloy systems, identifying promising compositions for more time-intensive experimental studies. We find the surprising result that solid solution alloys become less likely as the number of alloy elements increases. This contradicts the major premise of HEAs—that increased configurational entropy increases the stability of disordered solid solution phases. As the number of elements increases, the configurational entropy rises slowly while the probability of at least one pair of elements favouring formation of intermetallic compounds increases more rapidly, explaining this apparent contradiction. PMID:25739749

  6. Subscale solid motor nozzle tests, phase 4 and nozzle materials screening and thermal characterization, phase 5

    NASA Technical Reports Server (NTRS)

    Arnold, J.; Dodson, J.; Laub, B.

    1979-01-01

    Subscale solid motor nozzles containing a baseline material or low cost materials to be considered as potential replacements for the baseline material are designed and tested. Data are presented from tests of four identically designed 2.5 inch throat diameter nozzles and one 7 inch throat diameter nozzle. The screening of new candidate low cost materials, as well as their thermophysical and thermochemical characterization is also discussed.

  7. Formation routes of interstellar glycine involving carboxylic acids: possible favoritism between gas and solid phase.

    PubMed

    Pilling, Sergio; Baptista, Leonardo; Boechat-Roberty, Heloisa M; Andrade, Diana P P

    2011-11-01

    Despite the extensive search for glycine (NH₂CH₂COOH) and other amino acids in molecular clouds associated with star-forming regions, only upper limits have been derived from radio observations. Nevertheless, two of glycine's precursors, formic acid and acetic acid, have been abundantly detected. Although both precursors may lead to glycine formation, the efficiency of reaction depends on their abundance and survival in the presence of a radiation field. These facts could promote some favoritism in the reaction pathways in the gas phase and solid phase (ice). Glycine and these two simplest carboxylic acids are found in many meteorites. Recently, glycine was also observed in cometary samples returned by the Stardust space probe. The goal of this work was to perform theoretical calculations for several interstellar reactions involving the simplest carboxylic acids as well as the carboxyl radical (COOH) in both gas and solid (ice) phase to understand which reactions could be the most favorable to produce glycine in interstellar regions fully illuminated by soft X-rays and UV, such as star-forming regions. The calculations were performed at four different levels for the gas phase (B3LYP/6-31G*, B3LYP/6-31++G**, MP2/6-31G*, and MP2/6-31++G**) and at MP2/6-31++G** level for the solid phase (ice). The current two-body reactions (thermochemical calculation) were combined with previous experimental data on the photodissociation of carboxylic acids to promote possible favoritism for glycine formation in the scenario involving formic and acetic acid in both gas and solid phase. Given that formic acid is destroyed more in the gas phase by soft X-rays than acetic acid is, we suggest that in the gas phase the most favorable reactions are acetic acid with NH or NH₂OH. Another possible reaction involves NH₂CH₂ and COOH, one of the most-produced radicals from the photodissociation of acetic acid. In the solid phase, we suggest that the reactions of formic acid with NH

  8. Lights and shadows of anti-HLA antibodies detected by solid-phase assay.

    PubMed

    Picascia, Antonietta; Sabia, Chiara; Grimaldi, Vincenzo; Montesano, Maria Lourdes; Sommese, Linda; Schiano, Concetta; Napoli, Claudio

    2014-11-01

    Recently, management of patients awaiting solid organ transplantation has taken advantages after the development of more sensitive and accurate solid phase assays which have supported the historic complement dependent cytotoxicity. This approach has allowed the detection of antibodies in patients previously considered negative. The use of the single antigen beads resulted in a more accurate anti-human leukocyte antigen (HLA) antibody characterization. The detection of anti-HLA antibodies specific for C, DQ and DP loci that were not so well characterized has been possible through the implementation of the single antigen assay. The assessment of HLA compatibility has been expanded through the introduction of "epitope matching" concept and the definition of the unacceptable antigens for a more adequate evaluation of donor-recipient compatibility. However, the clinical impact of pre-formed and de novo anti-HLA antibodies detected by solid phase assays is still controversial due to the drawback related to result interpretation. Until today, the unresolved issues concern if all antibodies affect the medium and long term clinical outcome. An open debate on the clinical relevance of anti-HLA antibodies detected by single-antigen beads highlights needing to further investigations. Here, we describe the novel applications and the improvements of the solid-phase assay use. PMID:25171913

  9. Solid/Liquid phase diagram of the ammonium sulfate/maleic acid/water system.

    PubMed

    Beyer, Keith D; Schroeder, Jason R; Pearson, Christian S

    2011-12-01

    We have studied the low temperature phase diagram and water activities of the ammonium sulfate/maleic acid/water system using differential scanning calorimetry and infrared spectroscopy of thin films. Using the results from our experiments, we have mapped the solid/liquid ternary phase diagram, determined the water activities based on the freezing point depression, and determined the ice/maleic acid phase boundary as well as the ternary eutectic composition and temperature. We also compare our results to the predictions of the extended AIM aerosol thermodynamics model and find good agreement for the ice melting points in the ice primary phase field of this system; however significant differences were found with respect to phase boundaries, maleic acid dissolution, and ammonium sulfate dissolution. PMID:22017680

  10. Identification of unwanted photoproducts of cosmetic preservatives in personal care products under ultraviolet-light using solid-phase microextraction and micro-matrix solid-phase dispersion.

    PubMed

    Alvarez-Rivera, Gerardo; Llompart, Maria; Garcia-Jares, Carmen; Lores, Marta

    2015-04-17

    The photochemical transformation of widely used cosmetic preservatives including benzoates, parabens, BHA, BHT and triclosan has been investigated in this work applying an innovative double-approach strategy: identification of transformation products in aqueous photodegradation experiments (UV-light, 254nm), followed by targeted screening analysis of such photoproducts in UV-irradiated cosmetic samples. Solid-phase microextraction (SPME) was applied, using different fiber coatings, in order to widen the range of detectable photoproducts in water, whereas UV-irradiated personal care products (PCPs) containing the target preservatives were extracted by micro-matrix solid-phase dispersion (micro-MSPD). Both SPME and micro-MSPD-based methodologies were successfully optimized and validated. Degradation kinetics of parent species, and photoformation of their transformation by-products were monitored by gas chromatography coupled to mass spectrometry (GC-MS). Thirty nine photoproducts were detected in aqueous photodegradation experiments, being tentatively identified based on their mass spectra. Transformation pathways between structurally related by-products, consistent with their kinetic behavior were postulated. The photoformation of unexpected photoproducts such as 2- and 4-hydroxybenzophenones, and 2,8-dichlorodibenzo-p-dioxin in PCPs are reported in this work for the first time.

  11. Solid-phase fullerene-like nanostructures as singlet oxygen photosensitizers in liquid media

    NASA Astrophysics Data System (ADS)

    Belousova, I. M.; Danilov, O. B.; Kiselev, V. M.; Kislyakov, I. M.; Kris'ko, T. K.; Murav'eva, T. D.; Videnichev, D. A.

    2007-04-01

    Singlet oxygen generation by fullerene and astralen containing surfaces and powders under visible irradiation was studied in water and organic liquids by means of 1Δ g state luminescence and chemical scavenger transmittance measurements. The chemical method, pioneered for solid photosensitizers of 10 II, allowed to measure the singlet oxygen concentration in the aqueous medium down to 10 8 cm -3. The singlet oxygen sensitizing by the solid-phase fullerene-containing systems was found to be 100 times less effective then by fullerene in solution. The results obtained confirm the applicability of these structures in biology and medicine.

  12. Thermal Decomposition of the Solid Phase of Nitromethane: Ab Initio Molecular Dynamics Simulations

    NASA Astrophysics Data System (ADS)

    Chang, Jing; Lian, Peng; Wei, Dong-Qing; Chen, Xiang-Rong; Zhang, Qing-Ming; Gong, Zi-Zheng

    2010-10-01

    The Car-Parrinello molecular dynamics simulations were employed to investigate thermal decomposition of the solid nitromethane. It is found that it undergoes chemical decomposition at about 2200 K under ambient pressure. The initiation of reactions involves both proton transfer and commonly known C-N bond cleavage. About 75 species and 100 elementary reactions were observed with the final products being H2O, CO2, N2, and CNCNC. It represents the first complete simulation of solid-phase explosive reactions reported to date, which is of far-reaching implication for design and development of new energetic materials.

  13. Thermal decomposition of the solid phase of nitromethane: ab initio molecular dynamics simulations.

    PubMed

    Chang, Jing; Lian, Peng; Wei, Dong-Qing; Chen, Xiang-Rong; Zhang, Qing-Ming; Gong, Zi-Zheng

    2010-10-29

    The Car-Parrinello molecular dynamics simulations were employed to investigate thermal decomposition of the solid nitromethane. It is found that it undergoes chemical decomposition at about 2200 K under ambient pressure. The initiation of reactions involves both proton transfer and commonly known C-N bond cleavage. About 75 species and 100 elementary reactions were observed with the final products being H2O, CO2, N2, and CNCNC. It represents the first complete simulation of solid-phase explosive reactions reported to date, which is of far-reaching implication for design and development of new energetic materials. PMID:21231142

  14. alpha-DNA. VII. Solid phase synthesis of alpha-anomeric oligodeoxyribonucleotides.

    PubMed Central

    Morvan, F; Rayner, B; Leonetti, J P; Imbach, J L

    1988-01-01

    An efficient procedure for the synthesis of unnatural alpha-anomeric oligodeoxyribonucleotides is described. This solid-phase procedure is based on the use of alpha-nucleoside phosphoramidites and alpha-nucleoside derivatized solid supports corresponding to the four natural bases and allow rapid synthesis of oligonucleotides up to 20 alpha-deoxynucleotide units in length. After HPLC purification, a 15-mer: alpha-d(CCTCTCGTTCTTTAC) and a 20-mer: alpha-d(ATACTTGAGGAAGAGGTGTT) were obtained respectively in 27 and 29% overall yields. Their purity, nucleoside composition and primary structure were ascertained by HPLC and Maxam-Gilbert sequence analyses. Images PMID:3344220

  15. Affinity chromatography: a historical perspective.

    PubMed

    Hage, David S; Matsuda, Ryan

    2015-01-01

    Affinity chromatography is one of the most selective and versatile forms of liquid chromatography for the separation or analysis of chemicals in complex mixtures. This method makes use of a biologically related agent as the stationary phase, which provides an affinity column with the ability to bind selectively and reversibly to a given target in a sample. This review examines the early work in this method and various developments that have lead to the current status of this technique. The general principles of affinity chromatography are briefly described as part of this discussion. Past and recent efforts in the generation of new binding agents, supports, and immobilization methods for this method are considered. Various applications of affinity chromatography are also summarized, as well as the influence this field has played in the creation of other affinity-based separation or analysis methods. PMID:25749941

  16. Investigating the solid-liquid phase transition of water nanofilms using the generalized replica exchange method

    NASA Astrophysics Data System (ADS)

    Lu, Qing; Kim, Jaegil; Farrell, James D.; Wales, David J.; Straub, John E.

    2014-11-01

    The generalized Replica Exchange Method (gREM) was applied to study a solid-liquid phase transition in a nanoconfined bilayer water system using the monatomic water (mW) model. Exploiting optimally designed non-Boltzmann sampling weights with replica exchanges, gREM enables an effective sampling of configurations that are metastable or unstable in the canonical ensemble via successive unimodal energy distributions across phase transition regions, often characterized by S-loop or backbending in the statistical temperature. Extensive gREM simulations combined with Statistical Temperature Weighted Histogram Analysis Method (ST-WHAM) for nanoconfined mW water at various densities provide a comprehensive characterization of diverse thermodynamic and structural properties intrinsic to phase transitions. Graph representation of minimized structures of bilayer water systems determined by the basin-hopping global optimization revealed heterogeneous ice structures composed of pentagons, hexagons, and heptagons, consistent with an increasingly ordered solid phase with decreasing density. Apparent crossover from a first-order solid-liquid transition to a continuous one in nanoconfined mW water with increasing density of the system was observed in terms of a diminishing S-loop in the statistical temperature, smooth variation of internal energies and heat capacities, and a characteristic variation of lateral radial distribution functions, and transverse density profiles across transition regions.

  17. Investigating the solid-liquid phase transition of water nanofilms using the generalized replica exchange method

    SciTech Connect

    Lu, Qing; Kim, Jaegil; Straub, John E.; Farrell, James D.; Wales, David J.

    2014-11-14

    The generalized Replica Exchange Method (gREM) was applied to study a solid-liquid phase transition in a nanoconfined bilayer water system using the monatomic water (mW) model. Exploiting optimally designed non-Boltzmann sampling weights with replica exchanges, gREM enables an effective sampling of configurations that are metastable or unstable in the canonical ensemble via successive unimodal energy distributions across phase transition regions, often characterized by S-loop or backbending in the statistical temperature. Extensive gREM simulations combined with Statistical Temperature Weighted Histogram Analysis Method (ST-WHAM) for nanoconfined mW water at various densities provide a comprehensive characterization of diverse thermodynamic and structural properties intrinsic to phase transitions. Graph representation of minimized structures of bilayer water systems determined by the basin-hopping global optimization revealed heterogeneous ice structures composed of pentagons, hexagons, and heptagons, consistent with an increasingly ordered solid phase with decreasing density. Apparent crossover from a first-order solid-liquid transition to a continuous one in nanoconfined mW water with increasing density of the system was observed in terms of a diminishing S-loop in the statistical temperature, smooth variation of internal energies and heat capacities, and a characteristic variation of lateral radial distribution functions, and transverse density profiles across transition regions.

  18. Kerr-AdS analogue of triple point and solid/liquid/gas phase transition

    NASA Astrophysics Data System (ADS)

    Altamirano, Natacha; Kubizňák, David; Mann, Robert B.; Sherkatghanad, Zeinab

    2014-02-01

    We study the thermodynamic behavior of multi-spinning d = 6 Kerr-anti de Sitter black holes in the canonical ensemble of fixed angular momenta J1 and J2. We find, dependent on the ratio q = J2/J1, qualitatively different interesting phenomena known from the ‘every day thermodynamics’ of simple substances. For q = 0 the system exhibits recently observed reentrant large/small/large black hole phase transitions, but for 0 < q ≪ 1 we find an analogue of a ‘solid/liquid’ phase transition. Furthermore, for q ∈ (0.00905, 0.0985) the system displays the presence of a large/intermediate/small black hole phase transition with two critical and one triple (or tricritical) points. This behavior is reminiscent of the solid/liquid/gas phase transition except that the coexistence line of small and intermediate black holes does not continue for an arbitrary value of pressure (similar to the solid/liquid coexistence line) but rather terminates at one of the critical points. Finally, for q > 0.0985 we observe the ‘standard liquid/gas behavior’ of the Van der Waals fluid.

  19. Automated Solution-Phase Synthesis of Insect Glycans to Probe the Binding Affinity of Pea Enation Mosaic Virus

    PubMed Central

    2016-01-01

    Pea enation mosaic virus (PEMV)—a plant RNA virus transmitted exclusively by aphids—causes disease in multiple food crops. However, the aphid-virus interactions required for disease transmission are poorly understood. For virus transmission, PEMV binds to a heavily glycosylated receptor aminopeptidase N in the pea aphid gut and is transcytosed across the gut epithelium into the aphid body cavity prior to release in saliva as the aphid feeds. To investigate the role of glycans in PEMV–aphid interactions and explore the possibility of viral control through blocking a glycan interaction, we synthesized insect N-glycan terminal trimannosides by automated solution-phase synthesis. The route features a mannose building block with C-5 ester enforcing a β-linkage, which also provides a site for subsequent chain extension. The resulting insect N-glycan terminal trimannosides with fluorous tags were used in a fluorous microarray to analyze binding with fluorescein isothiocyanate-labeled PEMV; however, no specific binding between the insect glycan and PEMV was detected. To confirm these microarray results, we removed the fluorous tag from the trimannosides for isothermal titration calorimetry studies with unlabeled PEMV. The ITC studies confirmed the microarray results and suggested that this particular glycan–PEMV interaction is not involved in virus uptake and transport through the aphid. PMID:26457763

  20. Automated Solution-Phase Synthesis of Insect Glycans to Probe the Binding Affinity of Pea Enation Mosaic Virus.

    PubMed

    Tang, Shu-Lun; Linz, Lucas B; Bonning, Bryony C; Pohl, Nicola L B

    2015-11-01

    Pea enation mosaic virus (PEMV)--a plant RNA virus transmitted exclusively by aphids--causes disease in multiple food crops. However, the aphid-virus interactions required for disease transmission are poorly understood. For virus transmission, PEMV binds to a heavily glycosylated receptor aminopeptidase N in the pea aphid gut and is transcytosed across the gut epithelium into the aphid body cavity prior to release in saliva as the aphid feeds. To investigate the role of glycans in PEMV-aphid interactions and explore the possibility of viral control through blocking a glycan interaction, we synthesized insect N-glycan terminal trimannosides by automated solution-phase synthesis. The route features a mannose building block with C-5 ester enforcing a β-linkage, which also provides a site for subsequent chain extension. The resulting insect N-glycan terminal trimannosides with fluorous tags were used in a fluorous microarray to analyze binding with fluorescein isothiocyanate-labeled PEMV; however, no specific binding between the insect glycan and PEMV was detected. To confirm these microarray results, we removed the fluorous tag from the trimannosides for isothermal titration calorimetry studies with unlabeled PEMV. The ITC studies confirmed the microarray results and suggested that this particular glycan-PEMV interaction is not involved in virus uptake and transport through the aphid. PMID:26457763

  1. Automated Solution-Phase Synthesis of Insect Glycans to Probe the Binding Affinity of Pea Enation Mosaic Virus.

    PubMed

    Tang, Shu-Lun; Linz, Lucas B; Bonning, Bryony C; Pohl, Nicola L B

    2015-11-01

    Pea enation mosaic virus (PEMV)--a plant RNA virus transmitted exclusively by aphids--causes disease in multiple food crops. However, the aphid-virus interactions required for disease transmission are poorly understood. For virus transmission, PEMV binds to a heavily glycosylated receptor aminopeptidase N in the pea aphid gut and is transcytosed across the gut epithelium into the aphid body cavity prior to release in saliva as the aphid feeds. To investigate the role of glycans in PEMV-aphid interactions and explore the possibility of viral control through blocking a glycan interaction, we synthesized insect N-glycan terminal trimannosides by automated solution-phase synthesis. The route features a mannose building block with C-5 ester enforcing a β-linkage, which also provides a site for subsequent chain extension. The resulting insect N-glycan terminal trimannosides with fluorous tags were used in a fluorous microarray to analyze binding with fluorescein isothiocyanate-labeled PEMV; however, no specific binding between the insect glycan and PEMV was detected. To confirm these microarray results, we removed the fluorous tag from the trimannosides for isothermal titration calorimetry studies with unlabeled PEMV. The ITC studies confirmed the microarray results and suggested that this particular glycan-PEMV interaction is not involved in virus uptake and transport through the aphid.

  2. Electron Shuttling Capacity of Solid-Phase Organic Matter in Forest Soils

    NASA Astrophysics Data System (ADS)

    Patel, A.; Zhao, Q.; Yang, Y.

    2015-12-01

    Soil organic matter, as an electron shuttle, plays an important role in regulating the biogeochemical cycles of metals, especially the redox reactions for iron. Microorganisms can reduce soil organic matter under anaerobic conditions, and biotically-reduced soil organic matter can abiotically donate electrons to ferric oxides. Such soil organic matter-mediated electron transport can facilitate the interactions between microorganisms and insoluble terminal electron acceptors, i.e. iron minerals. Most previous studies have been focused on the electron shuttling processes through dissolved soil organic matter, and scant information is available for solid-phase soil organic matter. In this study, we aim to quantify the electron accepting capacity for solid-phase organic matter in soils collected from four different forests in the United States, including Truckee (CA), Little Valley (NV), Howland (ME) and Hart (MI). We used Shewanella oneidensisMR-1 to biotically reduce soil slurries, and then quantified the electrons transferred to solid-phase and solution-phase organic matter by reacting them with Fe(III)-nitrilotriacetic acid (Fe(III)-NTA). The generation of Fe(II) was measured by a ferrozine assay to calculate the electron accepting capacity of soil organic matter. Our preliminary results showed that the Truckee soil organic matter can accept 0.51±0.07 mM e-/mol carbon. We will measure the electron accepting capacity for four different soils and correlate them to the physicochemical properties of soils. Potential results will provide information about the electron accepting capacity of solid-phase soil organic matter and its governing factors, with broad implication on the coupled biogeochemical cycles of carbon and iron.

  3. SOLID PHASE CHARACTERIZATION OF HEEL SAMPLES FROM TANK 241-C-110

    SciTech Connect

    PAGE JS; COOKE GA; PESTOVICH JA; HUBER HJ

    2011-12-01

    During sluicing operations of tank 241-C-110, a significant amount of solids were unable to be retrieved. These solids (often referred to as the tank 'heel') were sampled in 2010 and chemically and mineralogically analyzed in the 222-S Laboratory. Additionally, dissolution tests were performed to identify the amount of undissolvable material after using multiple water contacts. This report covers the solid phase characterization of six samples from these tests using scanning electron microscopy, polarized light microscopy, and X-ray diffraction. The chemical analyses, particle size distribution analysis, and dissolution test results are reported separately. Two of the samples were from composites created from as-received material - Composite A and Composite B. The main phase in these samples was sodium-fluoride-phosphate hydrate (natrophosphate) - in the X-ray diffraction spectra, this phase was the only phase identifiable. Polarized light microscopy showed the presence of minor amounts of gibbsite and other phases. These phases were identified by scanning electron microscopy - energy dispersive X-ray spectroscopy as sodium aluminosilicates, sodium diuranate, and sodium strontium phosphate hydrate (nastrophite) crystals. The natrophosphate crystals in the scanning electron microscopy analysis showed a variety of erosive and dissolution features from perfectly shaped octahedral to well-rounded appearance. Two samples were from water-washed Composites A and B, with no change in mineralogy compared to the as-received samples. This is not surprising, since the water wash had only a short period of water contact with the material as opposed to the water dissolution tests. The last two samples were residual solids from the water dissolution tests. These tests included multiple additions of water at 15 C and 45 C. The samples were sieved to separate a coarser fraction of > 710 {mu}m and a finer fraction of < 710 {mu}m. These two fractions were analyzed separately. The

  4. Solid-State NMR Identification and Quantification of Newly Formed Aluminosilicate Phases in Weathered Kaolinite Systems

    SciTech Connect

    Crosson, Garry S.; Choi, Sunkyung; Chorover, Jon; Amistadi, Mary K.; O'Day, Peggy A.; Mueller, Karl T.

    2006-01-19

    The weathering of a specimen kaolinite clay was studied over the course of 369 d via solid-state 29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy and high-field 27Al MAS NMR. The chosen baseline solution conditions (0.05 mol kg-1 of Al, 2 mol kg-1 of Na+, 1 mol kg-1 of NO3 -, 1 mol kg-1 of OH-, and pH ~13.8) approximate those of solutions leaking from waste tanks at the Hanford Site in Richland, WA. Nonradioactive Cs and Sr cations were added to this synthetic tank waste leachate (STWL) solution at concentrations of 10-3, 10-4, and 10-5 molal (m) to represent their radionuclide counterparts. The transformations of silicon- and aluminum-containing solid phase species were monitored quantitatively by using NMR spectroscopy, with the resulting spectra directly reporting the influence of the initial Cs and Sr on formation and transformation of the neo-formed solids. At the lowest concentration of Cs and Sr employed (10-5 m in each cation) peaks consistent with the formation of zeolite-like minerals were detected via 29Si and 27Al MAS NMR as early as 33 d. At concentrations of 10-3 m in each cation, new silicon species are not detected until 93 d, although neophases containing four-coordinate aluminum were detectable at earlier reaction times via 27Al MAS NMR. At the highest magnetic field strengths employed in this NMR study, deconvolutions of resonances detected in the tetrahedral region of the 27Al MAS spectra yielded multiple components, indicating the existence of at least four new aluminum-containing phases. Two of these phases are identified as sodalite and cancrinite through comparison with diffuse-reflectance infrared (DRIFT) spectra and powder X-ray diffraction (XRD) results, while a third phase may correlate with a previously detected aluminum-rich chabazite phase. All measurable solid reaction products have been quantified via their 27Al MAS resonances acquired at high magnetic field strengths (17.6 T), and the quantitative

  5. Method and apparatus for acoustic plate mode liquid-solid phase transition detection

    DOEpatents

    Blair, Dianna S.; Freye, Gregory C.; Hughes, Robert C.; Martin, Stephen J.; Ricco, Antonio J.

    1993-01-01

    A method and apparatus for sensing a liquid-solid phase transition event is provided which comprises an acoustic plate mode detecting element placed in contact with a liquid or solid material which generates a high-frequency acoustic wave that is attenuated to an extent based on the physical state of the material is contact with the detecting element. The attenuation caused by the material in contact with the acoustic plate mode detecting element is used to determine the physical state of the material being detected. The method and device are particularly suited for detecting conditions such as the icing and deicing of wings of an aircraft. In another aspect of the present invention, a method is provided wherein the adhesion of a solid material to the detecting element can be measured using the apparatus of the invention.

  6. Characterization of particle morphology of biochanin A molecularly imprinted polymers and their properties as a potential sorbent for solid-phase extraction.

    PubMed

    Chrzanowska, Anna M; Poliwoda, Anna; Wieczorek, Piotr P

    2015-04-01

    Molecularly imprinted polymers (MIPs) with biochanin A as a template were obtained using a bulk polymerization with non-covalent imprinting approach. The polymers were prepared in acetonitrile as porogen, using ethylene glycol dimethacrylate (EDMA) as cross-linking agent. The synthesis, with an application of 1',1'-azobis(cyclohexanecarbonitrile) (ACHN) as an initiator, has been performed thermally. During the synthesis process the effect of different functional monomers such as methacrylic acid (MAA), acrylamide (AA) and 4-vinylpyridine (4-VP) was investigated. The application of nitrogen sorption porosimetry, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) permitted the characterization and evaluation of synthesized polymers. The adsorption capacity of obtained MIPs was checked by using the binding testing. All synthesized polymers were evaluated as solid-phase extraction (SPE) sorbents for isolation and preconcentration of biochanin A and its analogues, daidzein and genistein. The MIPs exhibited higher affinity for biochanin A over competitive compounds. PMID:25687010

  7. Thermodynamic Model Formulations for Inhomogeneous Solids with Application to Non-isothermal Phase Field Modelling

    NASA Astrophysics Data System (ADS)

    Gladkov, Svyatoslav; Kochmann, Julian; Reese, Stefanie; Hütter, Markus; Svendsen, Bob

    2016-04-01

    The purpose of the current work is the comparison of thermodynamic model formulations for chemically and structurally inhomogeneous solids at finite deformation based on "standard" non-equilibrium thermodynamics [SNET: e. g. S. de Groot and P. Mazur, Non-equilibrium Thermodynamics, North Holland, 1962] and the general equation for non-equilibrium reversible-irreversible coupling (GENERIC) [H. C. Öttinger, Beyond Equilibrium Thermodynamics, Wiley Interscience, 2005]. In the process, non-isothermal generalizations of standard isothermal conservative [e. g. J. W. Cahn and J. E. Hilliard, Free energy of a non-uniform system. I. Interfacial energy. J. Chem. Phys. 28 (1958), 258-267] and non-conservative [e. g. S. M. Allen and J. W. Cahn, A macroscopic theory for antiphase boundary motion and its application to antiphase domain coarsening. Acta Metall. 27 (1979), 1085-1095; A. G. Khachaturyan, Theory of Structural Transformations in Solids, Wiley, New York, 1983] diffuse interface or "phase-field" models [e. g. P. C. Hohenberg and B. I. Halperin, Theory of dynamic critical phenomena, Rev. Modern Phys. 49 (1977), 435-479; N. Provatas and K. Elder, Phase Field Methods in Material Science and Engineering, Wiley-VCH, 2010.] for solids are obtained. The current treatment is consistent with, and includes, previous works [e. g. O. Penrose and P. C. Fife, Thermodynamically consistent models of phase-field type for the kinetics of phase transitions, Phys. D 43 (1990), 44-62; O. Penrose and P. C. Fife, On the relation between the standard phase-field model and a "thermodynamically consistent" phase-field model. Phys. D 69 (1993), 107-113] on non-isothermal systems as a special case. In the context of no-flux boundary conditions, the SNET- and GENERIC-based approaches are shown to be completely consistent with each other and result in equivalent temperature evolution relations.

  8. Microsticks as solid-phase carriers for enzyme-linked immunosorbent assays.

    PubMed Central

    Shekarchi, I C; Sever, J L; Ward, L A; Madden, D L

    1982-01-01

    Microsticks are machine-tooled or molded pegs of plastic or stainless steel which were developed as solid-phase carriers for the enzyme-linked immunosorbent assay (ELISA). They consist of a stem, which can be coated with plastic to be used as the reactive surface, and a shaft designed for easy handling and labeling and for positioning the sticks in microtiter wells and transfer plates. Microsticks permit a wide selection of coating materials and afford the user greater control over quality and standardization of the solid-phase surface. Polycarbonate and nitrocellulose coatings were tested in ELISAs for antibodies to measles virus, toxoplasma, and human gamma globulin. The Microsticks were found to give reproducible, sensitive, and specific ELISA results and minimized problems due to lot-to-lot and batch-to-batch variations found with other plastic carriers. PMID:6761355

  9. Solid phase graft copolymerization of acrylic monomers onto thermoplastics and their use as blend compatibilizers

    NASA Astrophysics Data System (ADS)

    Subramanian, Srinivas

    This research work is an extension of some of the earlier work done on the development of solid phase grafting technique to graft various monomers onto polymers as well as postulation of the usefulness of the graft copolymers thus synthesized. Polystyrene grafted with acrylic acid, previously developed in bench scale, was synthesized in pilot-plant scale batches. Process parameter studies on the grafting of acrylic acid onto polypropylene and developmental studies on the grafting of maleic anhydride onto polystyrene were also done. Polymers grafted with polar molecules such as maleic anhydride and acrylic acid have been used to compatibilize immiscible blends of polar and non-polar polymers. On the same note, the applicability of the solid phase graft copolymers as blend compatibilizers were investigated and their performance was compared to commercially available compatibilizers. Solid phase graft copolymerization process is a technique to synthesize graft copolymers. Some of its salient features are use of minimal solvent to conduct the reaction and easy equipment modification. It is a low pressure and low temperature process. This technique provides a viable alternative to the environmentally hazardous, and time consuming conventional process currently in use. Hence, development of this technique could be beneficial not only to the plastics industry, but also to mankind. Also, this technique provides a low-cost and extremely easy method to develop graft copolymers such as acrylic acid functionalized polymers that are rapidly gaining popularity as blend compatibilizers and polymer reinforcing agents. A study that proves the potential of these solid phase graft copolymers as good blend compatibilizers for industrially important immiscible polymers will develop interest in the industries about this grafting process. The free radical solid phase graft copolymerization process was carried in a modified Brabender-type mixer fitted with specially designed blades to

  10. Quantitation of Binding, Recovery and Desalting Efficiency in Solid Phase Extraction Micropipette Tips

    SciTech Connect

    Palmblad, M N; Vogel, J S

    2004-08-02

    Micropipette-tip solid phase extraction systems are common in proteomic analyses for desalting and concentrating samples for mass spectrometry, removing interferences, and increasing sensitivity. These systems are inexpensive, disposable, and highly efficient. Here we show micropipette-tip solid phase extraction is a direct sample preparation method for {sup 14}C-accelerator mass spectrometry (AMS), removing salts or reagent from labeled macromolecules. We compared loading, recovery and desalting efficiency in commercially available SPE micro-tips using {sup 14}C-labeled peptides and proteins, AMS, and alpha spectrometry ion energy loss quantitation. The polypropylene in the tips was nearly {sup 14}C-free and simultaneously provided low-background carrier for AMS. The silica material did not interfere with the analysis. Alpha spectrometry provided an absolute measurement of desalting efficiency.

  11. Synthesis and evaluation of silver nanoparticles material for solid phase extraction of cobalt from water samples

    NASA Astrophysics Data System (ADS)

    Khajeh, Mostafa; Sanchooli, Esmael

    2011-12-01

    In this study, a new solid phase extractor, nano-scale silver particles were synthesized. The silver nanoparticle-based solid phase extraction was used for separation and preconcentration of the trace amount of cobalt ion from various water samples prior to its determination by flame atomic absorption spectrometry. The effects of various parameters, including pH, amount of complexing agent [1-(2-pyridylazo)-2-naphthol] (PAN), flow rates of solution and eluent, type and least amount of the eluent for elution of the cobalt from silver nanoparticles were studied and optimized. Under the optimum conditions, the detection limit of this procedure was 0.78 μg L-1, and the relative standard deviation (RSD%) was 3.1% ( n = 10, c = 20 μg L-1). This method was applied to the determination of cobalt in water samples.

  12. Solid-phase assay of lectin activity using HRP-conjugated glycoproteins.

    PubMed

    Kojima-Aikawa, Kyoko

    2014-01-01

    Various enzyme-conjugated probes have been widely used for detection of specific interactions between biomolecules. In the case of glycan-protein interaction, horseradish peroxidase (HRP)-conjugated glycoproteins (HRP-GPs) are useful for the detection of carbohydrate-binding activity of plant and animal lectins. In this chapter, a typical solid-phase assay of the carbohydrate-binding activity of Sophora japonica agglutinin I, a Gal/GalNAc-specific lectin, using HRP-conjugated asialofetuin is described. HRP-GPs are versatile tools for probing lectin activities in crude extracts, screening many samples at one time, and applicable not only for solid-phase binding assays but also samples which are dot- or Western-blotted onto the membrane. PMID:25117228

  13. Solid-phase epitaxy of silicon amorphized by implantation of the alkali elements rubidium and cesium

    SciTech Connect

    Maier, R.; Haeublein, V.; Ryssel, H.; Voellm, H.; Feili, D.; Seidel, H.; Frey, L.

    2012-11-06

    The redistribution of implanted Rb and Cs profiles in amorphous silicon during solid-phase epitaxial recrystallization has been investigated by Rutherford backscattering spectroscopy and secondary ion mass spectroscopy. For the implantation dose used in these experiments, the alkali atoms segregate at the a-Si/c-Si interface during annealing resulting in concentration peaks near the interface. In this way, the alkali atoms are moved towards the surface. Rutherford backscattering spectroscopy in ion channeling configuration was performed to measure average recrystallization rates of the amorphous silicon layers. Preliminary studies on the influence of the alkali atoms on the solid-phase epitaxial regrowth rate reveal a strong retardation compared to the intrinsic recrystallization rate.

  14. Solid-phase organic synthesis of polyisoprenoid alcohols with traceless sulfone linker.

    PubMed

    Chang, Yi-Fan; Liu, Chen-Yu; Guo, Chih-Wei; Wang, Yen-Chih; Fang, Jim-Min; Cheng, Wei-Chieh

    2008-09-19

    Solid-phase organic synthesis of polyprenols with a traceless sulfone linker is described. The polymer-bound benezenesulfinate is first linked with the "tail" building blocks of isoprenyl chlorides via S-alkylation. With use of dimsyl anion as an appropriate base, the polymer-bound alpha-sulfonyl carbanion is generated and coupled with other "body" building blocks in an efficient manner. After repeated processes and a global palladium-catalyzed desulfonation with LiEt 3BH as the reducing agent, the desired polyprenols with various chain lengths and geometrical configurations are obtained in 32-59% overall yields. The solid-phase synthesis offers the advantage in facile isolation of polyprenols without tedious operation or time-consuming purification.

  15. Designing room-temperature multiferroic materials in a single-phase solid-solution film

    NASA Astrophysics Data System (ADS)

    Mao, H. J.; Song, C.; Cui, B.; Peng, J. J.; Li, F.; Xiao, L. R.; Pan, F.

    2016-09-01

    The search for multiferroic materials with simultaneous ferroelectric and ferromagnetic properties in a single phase at room temperature continues to be fuelled from the perspective of developing multifunctional devices. Here we design a single-phase multiferroic La0.67Sr0.33MnO3-BaTiO3 film, which possesses epitaxial single-crystal and solid-solution structure, high magnetic Curie temperature (~640 K) as well as switchable ferroelectric polarization. Moreover, a notable strain-mediated magnetoelectric coupling at room temperature in the way of modulating the magnetism with an external applied voltage is also observed. The synthetic solid-solution multiferroic film may open an extraordinary avenue for exploring a series of room-temperature multiferroic materials.

  16. The Use of Aryl Hydrazide Linkers for the Solid Phase Synthesis of Chemically Modified Peptides

    SciTech Connect

    Woo, Y; Mitchell, A R; Camarero, J A

    2006-11-03

    Since Merrifield introduced the concept of solid phase synthesis in 1963 for the rapid preparation of peptides, a large variety of different supports and resin-linkers have been developed that improve the efficiency of peptide assembly and expand the myriad of synthetically feasible peptides. The aryl hydrazide is one of the most useful resin-linkers for the synthesis of chemically modified peptides. This linker is completely stable during Boc- and Fmoc-based solid phase synthesis and yet it can be cleaved under very mild oxidative conditions. The present article reviews the use of this valuable linker for the rapid and efficient synthesis of C-terminal modified peptides, head-to-tail cyclic peptides and lipidated peptides.

  17. Investigation of phase diagrams and physical stability of drug-polymer solid dispersions.

    PubMed

    Lu, Jiannan; Shah, Sejal; Jo, Seongbong; Majumdar, Soumyajit; Gryczke, Andreas; Kolter, Karl; Langley, Nigel; Repka, Michael A

    2015-01-01

    Solid dispersion technology has been widely explored to improve the solubility and bioavailability of poorly water-soluble compounds. One of the critical drawbacks associated with this technology is the lack of physical stability, i.e. the solid dispersion would undergo recrystallization or phase separation thus limiting a product's shelf life. In the current study, the melting point depression method was utilized to construct a complete phase diagram for felodipine (FEL)-Soluplus® (SOL) and ketoconazole (KTZ)-Soluplus® (SOL) binary systems, respectively, based on the Flory-Huggins theory. The miscibility or solubility of the two compounds in SOL was also determined. The Flory-Huggins interaction parameter χ values of both systems were calculated as positive at room temperature (25 °C), indicating either compound was miscible with SOL. In addition, the glass transition temperatures of both solid dispersion systems were theoretically predicted using three empirical equations and compared with the practical values. Furthermore, the FEL-SOL solid dispersions were subjected to accelerated stability studies for up to 3 months. PMID:25113671

  18. Solid/liquid phase diagram of the ammonium sulfate/succinic acid/water system.

    PubMed

    Pearson, Christian S; Beyer, Keith D

    2015-05-14

    We have studied the low-temperature phase diagram and water activities of the ammonium sulfate/succinic acid/water system using differential scanning calorimetry and infrared spectroscopy of thin films. Using the results from our experiments, we have mapped the solid/liquid ternary phase diagram, determined the water activities based on the freezing point depression, and determined the ice/succinic acid phase boundary as well as the ternary eutectic composition and temperature. We also compared our results to the predictions of the extended AIM aerosol thermodynamics model (E-AIM) and found good agreement for the ice melting points in the ice primary phase field of this system; however, differences were found with respect to succinic acid solubility temperatures. We also compared the results of this study with those of previous studies that we have published on ammonium sulfate/dicarboxylic acid/water systems. PMID:25431860

  19. Quantum Monte Carlo study of the phase diagram of solid molecular hydrogen at extreme pressures

    PubMed Central

    Drummond, N. D.; Monserrat, Bartomeu; Lloyd-Williams, Jonathan H.; Ríos, P. López; Pickard, Chris J.; Needs, R. J.

    2015-01-01

    Establishing the phase diagram of hydrogen is a major challenge for experimental and theoretical physics. Experiment alone cannot establish the atomic structure of solid hydrogen at high pressure, because hydrogen scatters X-rays only weakly. Instead, our understanding of the atomic structure is largely based on density functional theory (DFT). By comparing Raman spectra for low-energy structures found in DFT searches with experimental spectra, candidate atomic structures have been identified for each experimentally observed phase. Unfortunately, DFT predicts a metallic structure to be energetically favoured at a broad range of pressures up to 400 GPa, where it is known experimentally that hydrogen is non-metallic. Here we show that more advanced theoretical methods (diffusion quantum Monte Carlo calculations) find the metallic structure to be uncompetitive, and predict a phase diagram in reasonable agreement with experiment. This greatly strengthens the claim that the candidate atomic structures accurately model the experimentally observed phases. PMID:26215251

  20. Free energy model for solid high-pressure phases of carbon

    NASA Astrophysics Data System (ADS)

    Schöttler, Manuel; French, Martin; Cebulla, Daniel; Redmer, Ronald

    2016-04-01

    Analytic free energy models for three solid high-pressure phases—diamond, body centered cubic phase with eight atoms in the unit cell (BC8), and simple cubic (SC)—are developed using density functional theory. We explicitly include anharmonic effects by performing molecular dynamics simulations and investigate their density and temperature dependence in detail. Anharmonicity in the nuclear motion shifts the phase transitions significantly compared to the harmonic approximation. Furthermore, we apply a thermodynamically constrained correction that brings the equation of state in accordance with diamond anvil cell experiments. The performance of our thermodynamic functions is validated against Hugoniot experiments.

  1. The role of energetic processing on solid-phase chemistry in star forming regions

    NASA Astrophysics Data System (ADS)

    Palumbo, M. E.; Urso, R. G.; Kaňuchová, Z.; Scirè, C.; Accolla, M.; Baratta, G. A.; Strazzulla, G.

    2016-05-01

    It is generally accepted that complex molecules observed in star forming regions are formed in the solid phase on icy grain mantles and are released to the gas-phase after desorption of icy mantles. Most of our knowledge on the physical and chemical properties of ices in star forming regions is based on the comparison between observations and laboratory experiments performed at low temperature (10-100 K). Here we present some recent laboratory experiments which show the formation of (complex) molecular species after ion bombardment of simple ices.

  2. Diffusionless phase transition with two order parameters in spin-crossover solids

    SciTech Connect

    Gudyma, Iurii Ivashko, Victor; Linares, Jorge

    2014-11-07

    The quantitative analysis of the interface boundary motion between high-spin and low-spin phases is presented. The nonlinear effect of the switching front rate on the temperature is shown. A compressible model of spin-crossover solid is studied in the framework of the Ising-like model with two-order parameters under statistical approach, where the effect of elastic strain on interaction integral is considered. These considerations led to examination of the relation between the order parameters during temperature changes. Starting from the phenomenological Hamiltonian, entropy has been derived using the mean field approach. Finally, the phase diagram, which characterizes the system, is numerically analyzed.

  3. Stochastic simulation of fluctuation stage of phase transfer on solid surface during thin film formation

    SciTech Connect

    Bondareva, A.L.; Zmievskaya, G.I.

    2005-05-16

    Ions irradiation leads to nano-scale islands of thin cover formation. Influence on a solid surface of the following processes: fluctuation stage of phase transition (new phase island formation), its migration under long-range potentials of interaction which leads to brownian motion of islands on the surface, inelastic collisions of islands has been simulated by stochastic analogue method. The calculated time evolution of islands kinetic distribution function from islands square sizes and coordinates of its masses centres on the surface is calculated taking into account non-linear Gibbs energy of islands formation, which depends on lattice elastic responses as well on dislocation influence.

  4. Chromatographic Separations Using Solid-Phase Extraction Cartridges: Separation of Wine Phenolics

    NASA Astrophysics Data System (ADS)

    Brenneman, Charles A.; Ebeler, Susan E.

    1999-12-01

    We describe a simple laboratory experiment that demonstrates the principles of chromatographic separation using solid-phase extraction columns and red wine. By adjusting pH and mobile phase composition, the wine is separated into three fractions of differing polarity. The content of each fraction can be monitored by UV-vis spectroscopy. When the experiment is combined with experiments involving HPLC or GC separations, students gain a greater appreciation for and understanding of the highly automated instrumental systems currently available. In addition, they learn about the chemistry of polyphenolic compounds, which are present in many foods and beverages and which are receiving much attention for their potentially beneficial health effects.

  5. Solid-phase reduction of Cr2O3 under chemical catalytic conditions

    NASA Astrophysics Data System (ADS)

    Simonov, V. K.; Grishin, A. M.

    2016-06-01

    The kinetics of the solid-phase reduction of Cr2O3 with carbon under chemical catalytic action on the reacting system is studied. A significant intensification of the process in the presence of small amounts of potassium and sodium salts is established. The concepts of the catalyst action mechanism are considered and experimentally substantiated. Manufacture of iron-chromium master alloys with a restricted content of carbon can be organized at low temperatures, and they can be used in steelmaking.

  6. The sulfamate functional group as a new anchor for solid-phase organic synthesis

    PubMed

    Ciobanu; Maltais; Poirier

    2000-02-24

    [reaction: see text] Sulfamate derivatives were loaded on trityl chloride resin, and two variants of cleavage were developed for this sulfamate anchor: an acid treatment to easily restore the free sulfamate and a nucleophilic treatment to generate the corresponding phenol. In addition to loading/cleavage assays and stability experiments, a model sequence of reactions was performed with the new sulfamate anchor to show its applicability in further combinatorial solid-phase synthesis of libraries of biologically relevant sulfamate derivatives.

  7. Model of cohesive properties and structural phase transitions in non-metallic solids

    SciTech Connect

    Majewski, J.A.; Vogl, P.

    1986-01-01

    We have developed a simple, yet microscopic and universal model for cohesive properties of solids. This model explains the physical mechanisms determining the chemical and predicts semiquantitatively static and dynamic cohesive properties. It predicts a substantial softening of the long-wavelength transverse optical phonons across the pressure induced phase transition from the zincblenda to rocksalt structure in II-VI compounds. The origin of this softening is shown to be closely related to ferroelectricity.

  8. R. Bruce Merrifield and Solid-Phase Peptide Synthesis: A Historical Assessment

    SciTech Connect

    Mitchell, A R

    2007-12-04

    Bruce Merrifield, trained as a biochemist, had to address three major challenges related to the development and acceptance of solid-phase peptide synthesis (SPPS). The challenges were (1) to reduce the concept of peptide synthesis on a insoluble support to practice, (2) overcome the resistance of synthetic chemists to this novel approach, and (3) establish that a biochemist had the scientific credentials to effect the proposed revolutionary change in chemical synthesis. How these challenges were met is discussed in this article.

  9. Phase I study of afatinib combined with nintedanib in patients with advanced solid tumours

    PubMed Central

    Bahleda, Rastislav; Hollebecque, Antoine; Varga, Andrea; Gazzah, Anas; Massard, Christophe; Deutsch, Eric; Amellal, Nadia; Farace, Françoise; Ould-Kaci, Mahmoud; Roux, Flavien; Marzin, Kristell; Soria, Jean-Charles

    2015-01-01

    Background: This Phase I study evaluated continuous- and intermittent-dosing (every other week) of afatinib plus nintedanib in patients with advanced solid tumours. Methods: In the dose-escalation phase (n=45), maximum tolerated doses (MTDs) were determined for continuous/intermittent afatinib 10, 20, 30 or 40 mg once daily plus continuous nintedanib 150 or 200 mg twice daily. Secondary objectives included safety and efficacy. Clinical activity of continuous afatinib plus nintedanib at the MTD was further evaluated in an expansion phase (n=25). Results: The most frequent dose-limiting toxicities were diarrhoea (11%) and transaminase elevations (7%). Maximum tolerated doses were afatinib 30 mg continuously plus nintedanib 150 mg, and afatinib 40 mg intermittently plus nintedanib 150 mg. Treatment-related adverse events (mostly Grade ⩽3) included diarrhoea (98%), asthenia (64%), nausea (62%) and vomiting (60%). In the dose-escalation phase, two patients had partial responses (PRs) and 27 (60%) had stable disease (SD). In the expansion phase, one complete response and three PRs were observed (all non-small cell lung cancer), with SD in 13 (52%) patients. No pharmacokinetic interactions were observed. Conclusions: MTDs of continuous or intermittent afatinib plus nintedanib demonstrated a manageable safety profile with proactive management of diarrhoea. Antitumour activity was observed in patients with solid tumours. PMID:26512876

  10. Fragment-based solid-phase assembly of oligonucleotide conjugates with peptide and polyethylene glycol ligands.

    PubMed

    Dirin, Mehrdad; Urban, Ernst; Noe, Christian R; Winkler, Johannes

    2016-10-01

    Ligand conjugation to oligonucleotides is an attractive strategy for enhancing the therapeutic potential of antisense and siRNA agents by inferring properties such as improved cellular uptake or better pharmacokinetic properties. Disulfide linkages enable dissociation of ligands and oligonucleotides in reducing environments found in endosomal compartments after cellular uptake. Solution-phase fragment coupling procedures for producing oligonucleotide conjugates are often tedious, produce moderate yields and reaction byproducts are frequently difficult to remove. We have developed an improved method for solid-phase coupling of ligands to oligonucleotides via disulfides directly after solid-phase synthesis. A 2'-thiol introduced using a modified nucleotide building block was orthogonally deprotected on the controlled pore glass solid support with N-butylphosphine. Oligolysine peptides and a short monodisperse ethylene glycol chain were successfully coupled to the deprotected thiol. Cleavage from the resin and full removal of oligonucleotide protection groups were achieved using methanolic ammonia. After standard desalting, and without further purification, homogenous conjugates were obtained as demonstrated by HPLC, gel electrophoresis, and mass spectrometry. The attachment of both amphiphilic and cationic ligands proves the versatility of the conjugation procedure. An antisense oligonucleotide conjugate with hexalysine showed pronounced gene silencing in a cell culture tumor model in the absence of a transfection reagent and the corresponding ethylene glycol conjugate resulted in down regulation of the target gene to nearly 50% after naked application. PMID:27236069

  11. Bacterial migration and motion in a fluid phase and near a solid surface

    SciTech Connect

    Frymier, P.D. Jr.

    1995-01-01

    An understanding of the migration and motion of bacteria in a fluid phase and near solid surfaces is necessary to characterize processes such as the bioremediation of hazardous waste, the pathogenesis of infection, industrial biofouling and wastewater treatment, among others. This study addresses three questions concerning the prediction of the distribution of a population of bacteria in a fluid phase and the motion of bacteria near a solid surface: Under what conditions does a one-dimensional phenomenological model for the density of a population of chemotactic bacteria yield an adequate representation of the migration of bacteria subject to a one-dimensional attractant gradient? How are the values of transport coefficients obtained from experimental data affected by the use of the one-dimensional phenomenological model and also by the use of different descriptions of bacterial swimming behavior in a mathematically rigorous balance equation? How is the characteristic motion of bacteria swimming in a fluid affected by the presence of a solid phase? A computer simulation that rigorously models the movement of a large population of individual chemotactic bacteria in three dimensions is developed to test the validity of a one-dimensional phenomenological model for bacterial migration in a fluid.

  12. Solid-state synthesis and phase transformations in Ni/Fe films: Structural and magnetic studies

    NASA Astrophysics Data System (ADS)

    Myagkov, V. G.; Zhigalov, V. C.; Bykova, L. E.; Bondarenko, G. N.

    2006-10-01

    We have used X-ray diffraction, volume magnetocrystalline anisotropy constant and resistance measurements to study solid-state synthesis in Ni(0 0 1)/Fe(0 0 1), Ni/Fe(0 0 1) and Ni/Fe thin films with the atomic ratio between Fe and Ni of 1:1 (1Fe:1Ni), and 3:1 (3Fe:1Ni). We have found that the formation of Ni 3Fe and NiFe phases in the 1Fe:1Ni films takes place at temperatures ˜620 and ˜720 K, correspondingly. In the case of the 3Fe:1Ni films the solid-state synthesis starts with Ni 3Fe and NiFe phase formation at the same temperatures as for the 1Fe:1Ni films. The increasing of annealing temperature above 820 K leads to the nucleation of a paramagnetic γpar phase at the FeNi/Fe interface. The final products of solid-state synthesis in the Ni(0 0 1)/Fe(0 0 1) thin films are crystallites which consist of the epitaxially intergrown NiFe and γpar phases according to the [1 0 0](0 0 1)NiFe||[1 0 0](0 0 1) γpar orientation relationship. The crystalline perfection and epitaxial growth of the (NiFe+ γpar) crystallites on the MgO(0 0 1) surface allow to distinguish (0 0 2) γpar and (0 0 2)NiFe X-ray peaks (the cell parameters are: a( γpar)=0.3600±0.0005 nm and a(NiFe)=0.3578±0.0005 nm, correspondingly). At low temperatures the paramagnetic γpar phase undergoes the martensite γ→α' phase transition which can be hindered by thermal and epitaxial strains and epitaxial clamping with a MgO substrate. On the basis of the studies of the thin-film solid-state synthesis we predict the existence of two novel structural phase transformations at the temperatures of about 720 and 820 K for alloys of the invar region of the Fe-Ni system.

  13. A two-phase restricted equilibrium model for combustion of metalized solid propellants

    NASA Technical Reports Server (NTRS)

    Sabnis, J. S.; Dejong, F. J.; Gibeling, H. J.

    1992-01-01

    An Eulerian-Lagrangian two-phase approach was adopted to model the multi-phase reacting internal flow in a solid rocket with a metalized propellant. An Eulerian description was used to analyze the motion of the continuous phase which includes the gas as well as the small (micron-sized) particulates, while a Lagrangian description is used for the analysis of the discrete phase which consists of the larger particulates in the motor chamber. The particulates consist of Al and Al2O3 such that the particulate composition is 100 percent Al at injection from the propellant surface with Al2O3 fraction increasing due to combustion along the particle trajectory. An empirical model is used to compute the combustion rate for agglomerates while the continuous phase chemistry is treated using chemical equilibrium. The computer code was used to simulate the reacting flow in a solid rocket motor with an AP/HTPB/Al propellant. The computed results show the existence of an extended combustion zone in the chamber rather than a thin reaction region. The presence of the extended combustion zone results in the chamber flow field and chemical being far from isothermal (as would be predicted by a surface combustion assumption). The temperature in the chamber increases from about 2600 K at the propellant surface to about 3350 K in the core. Similarly the chemical composition and the density of the propellant gas also show spatially non-uniform distribution in the chamber. The analysis developed under the present effort provides a more sophisticated tool for solid rocket internal flow predictions than is presently available, and can be useful in studying apparent anomalies and improving the simple correlations currently in use. The code can be used in the analysis of combustion efficiency, thermal load in the internal insulation, plume radiation, etc.

  14. Enzyme oscillation can enhance the thermodynamic efficiency of cellular metabolism: consequence of anti-phase coupling between reaction flux and affinity

    NASA Astrophysics Data System (ADS)

    Himeoka, Yusuke; Kaneko, Kunihiko

    2016-04-01

    Cells generally convert nutrient resources to products via energy transduction. Accordingly, the thermodynamic efficiency of this conversion process is one of the most essential characteristics of living organisms. However, although these processes occur under conditions of dynamic metabolism, most studies of cellular thermodynamic efficiency have been restricted to examining steady states; thus, the relevance of dynamics to this efficiency has not yet been elucidated. Here, we develop a simple model of metabolic reactions with anabolism-catabolism coupling catalyzed by enzymes. Through application of external oscillation in the enzyme abundances, the thermodynamic efficiency of metabolism was found to be improved. This result is in strong contrast with that observed in the oscillatory input, in which the efficiency always decreased with oscillation. This improvement was effectively achieved by separating the anabolic and catabolic reactions, which tend to disequilibrate each other, and taking advantage of the temporal oscillations so that each of the antagonistic reactions could progress near equilibrium. In this case, anti-phase oscillation between the reaction flux and chemical affinity through oscillation of enzyme abundances is essential. This improvement was also confirmed in a model capable of generating autonomous oscillations in enzyme abundances. Finally, the possible relevance of the improvement in thermodynamic efficiency is discussed with respect to the potential for manipulation of metabolic oscillations in microorganisms.

  15. Current challenges for pre-earthquake electromagnetic emissions: shedding light from micro-scale plastic flow, granular packings, phase transitions and self-affinity notion of fracture process

    NASA Astrophysics Data System (ADS)

    Eftaxias, K.; Potirakis, S. M.

    2013-10-01

    Are there credible electromagnetic (EM) potential earthquake (EQ) precursors? This a question debated in the scientific community and there may be legitimate reasons for the critical views. The negative view concerning the existence of EM potential precursors is enhanced by features that accompany their observation which are considered as paradox ones, namely, these signals: (i) are not observed at the time of EQs occurrence and during the aftershock period, (ii) are not accompanied by large precursory strain changes, (iii) are not accompanied by simultaneous geodetic or seismological precursors and (iv) their traceability is considered problematic. In this work, the detected candidate EM potential precursors are studied through a shift in thinking towards the basic science findings relative to granular packings, micron-scale plastic flow, interface depinning, fracture size effects, concepts drawn from phase transitions, self-affine notion of fracture and faulting process, universal features of fracture surfaces, recent high quality laboratory studies, theoretical models and numerical simulations. We try to contribute to the establishment of strict criteria for the definition of an emerged EM anomaly as a possibly EQ-related one, and to the explanation of potential precursory EM features which have been considered as paradoxes. A three-stage model for EQ generation by means of pre-EQ fracture-induced EM emissions is proposed. The claim that the observed EM potential precursors may permit a real-time and step-by-step monitoring of the EQ generation is tested.

  16. Development and elaboration of numerical method for simulating gas–liquid–solid three-phase flows based on particle method

    NASA Astrophysics Data System (ADS)

    Takahashi, Ryohei; Mamori, Hiroya; Yamamoto, Makoto

    2016-02-01

    A numerical method for simulating gas-liquid-solid three-phase flows based on the moving particle semi-implicit (MPS) approach was developed in this study. Computational instability often occurs in multiphase flow simulations if the deformations of the free surfaces between different phases are large, among other reasons. To avoid this instability, this paper proposes an improved coupling procedure between different phases in which the physical quantities of particles in different phases are calculated independently. We performed numerical tests on two illustrative problems: a dam-break problem and a solid-sphere impingement problem. The former problem is a gas-liquid two-phase problem, and the latter is a gas-liquid-solid three-phase problem. The computational results agree reasonably well with the experimental results. Thus, we confirmed that the proposed MPS method reproduces the interaction between different phases without inducing numerical instability.

  17. Modeling migrations of slab-derived fluid in deep crust based on the considerations of solid phase deformation and wettability of solid-liquid system

    NASA Astrophysics Data System (ADS)

    Ohta, J.; Tokunaga, T.

    2012-12-01

    In deep crust, it is considered that the solid phase tends to keep its polycrystalline structure while it flows as highly-viscous fluid, and that the fluid phase flows through polycrystalline solid as porous flow. Here, the solid-framework is considered to change its bulk volume due to the changes of fluid volumetric fraction. In addition, wettability of solid-liquid system, which is expressed as solid-liquid dihedral angle, is also considered to affect internal pore structure. Thus, the solid-framework deformation and wettability of solid-liquid system are considered to influence fluid migration. In this research, we firstly constructed the permeability model to formulate a relationship among solid-liquid dihedral angle, fluid fraction, and permeability based on the energetic and textural considerations of grain boundary interface. The permeability and the fluid fraction under minimum interfacial energy condition were expressed as functions of solid-liquid dihedral angle from this model. Then, we found that permeability can be written as functions of the fluid fraction and the permeability under minimum interfacial energy condition. Secondly, we formulated the deformation of solid-framework and fluid flow through the deforming framework. The governing equations included solid bulk viscosity and solid shear viscosity as necessary parameters to describe the behavior. Based on the derived governing equations, the one-dimensional numerical simulations were conducted with different solid viscosities. From the results where solid bulk/shear viscosity was set to be 1020 Pa×s, intervals with relatively high fluid fraction were formed and the intervals showed attenuated fluctuation of their fluid volume fraction. On the other hand, the results where solid bulk/shear viscosity was set to be 1019 Pa×s did not show such fluctuation. The complex interaction among fluid fraction, permeability, and solid viscosity could contribute to the observed phenomena, and further

  18. Numerical Computation of Flame Spread over a Thin Solid in Forced Concurrent Flow with Gas-phase Radiation

    NASA Technical Reports Server (NTRS)

    Jiang, Ching-Biau; T'ien, James S.

    1994-01-01

    Excerpts from a paper describing the numerical examination of concurrent-flow flame spread over a thin solid in purely forced flow with gas-phase radiation are presented. The computational model solves the two-dimensional, elliptic, steady, and laminar conservation equations for mass, momentum, energy, and chemical species. Gas-phase combustion is modeled via a one-step, second order finite rate Arrhenius reaction. Gas-phase radiation considering gray non-scattering medium is solved by a S-N discrete ordinates method. A simplified solid phase treatment assumes a zeroth order pyrolysis relation and includes radiative interaction between the surface and the gas phase.

  19. Simultaneous determination of four plant hormones in bananas by molecularly imprinted solid-phase extraction coupled with high performance liquid chromatography.

    PubMed

    Yan, Hongyuan; Wang, Fang; Han, Dandan; Yang, Gengliang

    2012-06-21

    A highly selective molecularly imprinted solid-phase extraction (MISPE) combined with liquid chromatography-ultraviolet detection was developed for the simultaneous isolation and determination of four plant hormones including indole-3-acetic acid (IAA), indole-3-propionic acid (IPA), indole-3-butyric acid (IBA) and 1-naphthaleneacetic acid (NAA) in banana samples. The new molecularly imprinted microspheres (MIMs) prepared by aqueous suspension polymerization using 3-hydroxy-2-naphthoic acid and 1-methylpiperazine as mimic templates performed with high selectivity and affinity for the four plant hormones, and applied as selective sorbents of solid-phase extraction could effectively eliminate the interferences of the banana matrix. Good linearity was obtained in a range of 0.04-4.00 μg g(-1) and the recoveries of the four plant hormones at three spiked levels ranged from 78.5 to 107.7% with the relative standard deviations (RSD) of less than 4.6%. The developed MISPE-HPLC protocol obviously improved the selectivity and eliminated the effect of template leakage on quantitative analysis, and could be applied for the determination of plant hormones in complicated biological samples.

  20. Liquid-liquid and liquid-solid phase separation and flocculation for a charged colloidal dispersion.

    PubMed

    Lai, S K; Wu, K L

    2002-10-01

    We model the intercolloidal interaction by a hard-sphere Yukawa repulsion to which is added the long-range van der Waals attraction. In comparison with the Derjaguin-Landau-Verwey-Overbeek repulsion, the Yukawa repulsion explicitly incorporates the spatial correlations between colloids and small ions. As a result, the repulsive part can be expressed analytically and has a coupling strength depending on the colloidal volume fraction. By use of this two-body potential of mean force and in conjunction with a second-order thermodynamic perturbation theory, we construct the colloidal Helmholtz free energy and use it to calculate the thermodynamic quantities, pressure and chemical potential, needed in the determination of the liquid-liquid and liquid-solid phase diagrams. We examine, in an aqueous charged colloidal dispersion, the effects of the Hamaker constant and particle size on the conformation of a stable liquid-liquid phase transition calculated with respect to the liquid-solid coexistence phases. We find that there exists a threshold Hamaker constant or particle size whose value demarcates the stable liquid-liquid coexistence phases from their metastable counterparts. Applying the same technique and using the energetic criterion, we extend our calculations to study the flocculation phenomenon in aqueous charged colloids. Here, we pay due attention to determining the loci of a stability curve stipulated for a given temperature T0, and obtain the parametric phase diagram of the Hamaker constant vs the coupling strength or, at given surface potential, the particle size. By imposing T0 to be the critical temperature T(c), i.e., setting k(B)T0 (=k(B)T(c)) equal to a reasonable potential barrier, we arrive at the stability curve that marks the irreversible/reversible phase transition. The interesting result is that there occurs a minimum size for the colloidal particles below (above) which the colloidal dispersion is driven to an irreversible (reversible) phase

  1. A two-phase solid/fluid model for dense granular flows including dilatancy effects

    NASA Astrophysics Data System (ADS)

    Mangeney, Anne; Bouchut, Francois; Fernandez-Nieto, Enrique; Koné, El-Hadj; Narbona-Reina, Gladys

    2016-04-01

    Describing grain/fluid interaction in debris flows models is still an open and challenging issue with key impact on hazard assessment [{Iverson et al.}, 2010]. We present here a two-phase two-thin-layer model for fluidized debris flows that takes into account dilatancy effects. It describes the velocity of both the solid and the fluid phases, the compression/dilatation of the granular media and its interaction with the pore fluid pressure [{Bouchut et al.}, 2016]. The model is derived from a 3D two-phase model proposed by {Jackson} [2000] based on the 4 equations of mass and momentum conservation within the two phases. This system has 5 unknowns: the solid and fluid velocities, the solid and fluid pressures and the solid volume fraction. As a result, an additional equation inside the mixture is necessary to close the system. Surprisingly, this issue is inadequately accounted for in the models that have been developed on the basis of Jackson's work [{Bouchut et al.}, 2015]. In particular, {Pitman and Le} [2005] replaced this closure simply by imposing an extra boundary condition at the surface of the flow. When making a shallow expansion, this condition can be considered as a closure condition. However, the corresponding model cannot account for a dissipative energy balance. We propose here an approach to correctly deal with the thermodynamics of Jackson's model by closing the mixture equations by a weak compressibility relation following {Roux and Radjai} [1998]. This relation implies that the occurrence of dilation or contraction of the granular material in the model depends on whether the solid volume fraction is respectively higher or lower than a critical value. When dilation occurs, the fluid is sucked into the granular material, the pore pressure decreases and the friction force on the granular phase increases. On the contrary, in the case of contraction, the fluid is expelled from the mixture, the pore pressure increases and the friction force diminishes. To

  2. Lattice model theory of the equation of state covering the gas, liquid, and solid phases

    NASA Technical Reports Server (NTRS)

    Bonavito, N. L.; Tanaka, T.; Chan, E. M.; Horiguchi, T.; Foreman, J. C.

    1975-01-01

    The three stable states of matter and the corresponding phase transitions were obtained with a single model. Patterned after Lennard-Jones and Devonshires's theory, a simple cubic lattice model containing two fcc sublattices (alpha and beta) is adopted. The interatomic potential is taken to be the Lennard-Jones (6-12) potential. Employing the cluster variation method, the Weiss and the pair approximations on the lattice gas failed to give the correct phase diagrams. Hybrid approximations were devised to describe the lattice term in the free energy. A lattice vibration term corresponding to a free volume correction is included semi-phenomenologically. The combinations of the lattice part and the free volume part yield the three states and the proper phase diagrams. To determine the coexistence regions, the equalities of the pressure and Gibbs free energy per molecule of the coexisting phases were utilized. The ordered branch of the free energy gives rise to the solid phase while the disordered branch yields the gas and liquid phases. It is observed that the triple point and the critical point quantities, the phase diagrams and the coexistence regions plotted are in good agreement with the experimental values and graphs for argon.

  3. Matrix solid-phase dispersion and solid-phase microextraction applied to study the distribution of fenbutatin oxide in grapes and white wine.

    PubMed

    Montes, R; Canosa, P; Lamas, J Pablo; Piñeiro, A; Orriols, I; Cela, R; Rodríguez, I

    2009-12-01

    The fate of the acaricide fenbutatin oxide (FBTO) during the elaboration of white wine is evaluated. Matrix solid-phase dispersion (MSPD) and solid-phase microextraction (SPME) were used as sample preparation techniques applied to the semi-solid and the liquid matrices involved in this research, respectively. Selective determination of FBTO was achieved by gas chromatography with atomic emission detection (GC-AED). GC coupled to mass spectrometry was also used to establish the identity of FBTO by-products detected in must and wine samples. MSPD extractions were accomplished using C18 as dispersant and co-sorbent. Sugars and other polar interferences were first removed with water and water/acetone mixtures, then FBTO was recovered with 8 mL of acetone. When used in combination with GC-AED, the MSPD method provided limits of quantification (LOQs) in the low nanogram per gram range, recoveries around 90% and relative standard deviations below 13% for extractions performed in different days. Performance of SPME for must and wine was mainly controlled by the extraction temperature, time and fibre coating. Under final conditions, FBTO was extracted in the headspace mode for 45 min at 100 degrees C, using a 100 microm poly(dimethylsiloxane)-coated fibre. The achieved LOQs remained around or below 0.1 ng mL(-1), depending on the type of sample, and the inter-day precision ranged from 10% to 13%. FBTO residues in grapes stayed mostly on the skin of the fruit. Although FBTO was not removed during must and white wine elaboration, it remained associated with suspended particles existing in must and lees, settled after must fermentation, with a negligible risk of being transferred to commercialised wine. On the other hand, two by-products of FBTO (bis and mono (2-methyl-2-phenylpropyl) tin) were identified, for first time, in must and final white wines obtained from FBTO treated grapes. Found values for the first species ranged from 0.03 to 0.9 ng mL(-1). PMID:19806346

  4. Variable-cell double-ended surface walking method for fast transition state location of solid phase transitions.

    PubMed

    Zhang, Xiao-Jie; Liu, Zhi-Pan

    2015-10-13

    To identify the low energy pathway for solid-to-solid phase transition has been a great challenge in physics and material science. This work develops a new theoretical method, namely, variable-cell double-ended surface walking (VC-DESW) to locate the transition state (TS) and deduce the pathway in solid phase transition. Inherited from the DESW method ( J. Chem. Theory Comput. 2013 , 9 , 5745 ) for molecular systems, the VC-DESW method implements an efficient mechanism to couple the lattice and atom degrees of freedom. The method features with fast pseudopathway building and accurate TS location for solid phase transition systems without requiring expensive Hessian computation and iterative pathway optimization. A generalized coordinate, consisting of the lattice vectors and the scaled atomic coordinates, is designed for describing the crystal potential energy surface (PES), which is able to capture the anisotropic behavior in phase transition. By comparing with the existing method for solid phase transition in different systems, we show that the VC-DESW method can be much more efficient for finding the TS in crystal phase transition. With the combination of the recently developed unbiased stochastic surface walking pathway sampling method, the VC-DESW is further utilized to resolve the lowest energy pathway of SiO2 α-quartz to quartz-II phase transition from many likely reaction pathways. These new methods provide a powerful platform for understanding and predicting the solid phase transition mechanism and kinetics.

  5. Distribution of organohalide-respiring bacteria between solid and aqueous phases.

    PubMed

    Cápiro, Natalie L; Wang, Yonggang; Hatt, Janet K; Lebrón, Carmen A; Pennell, Kurt D; Löffler, Frank E

    2014-09-16

    Contemporary microbial monitoring of aquifers relies on groundwater samples to enumerate nonattached cells of interest. One-dimensional column studies quantified the distribution of bacterial cells in solid and the aqueous phases as a function of microbial species, growth substrate availability and porous medium (i.e., Appling soil versus Federal Fine Ottawa sand with 0.75% and 0.01% [w/w] organic carbon, respectively). Without supplied growth substrates, effluent from columns inoculated with the tetrachloroethene- (PCE-) to-ethene-dechlorinating bacterial consortium BDI-SZ containing Dehalococcoides mccartyi (Dhc) strains and Geobacter lovleyi strain SZ (GeoSZ), or inoculated with Anaeromyxobacter dehalogenans strain W (AdehalW), captured 94-96, 81-99, and 73-84% of the Dhc, GeoSZ, and AdehalW cells, respectively. Cell retention was organism-specific and increased in the order Dhc < GeoSZ < AdehalW. When amended with 10 mM lactate and 0.11 mM PCE, aqueous samples accounted for 1.3-27 and 0.02-22% of the total Dhc and GeoSZ biomass, respectively. In Appling soil, up to three orders-of-magnitude more cells were associated with the solid phase, and attachment rate coefficients (katt) were consistently greater compared to Federal Fine sand. Cell-solid interaction energies ranged from -2.5 to 787 kT and were consistent with organism-specific deposition behavior, where GeoSZ and AdehalW exhibited greater attachment than Dhc cells. The observed disparities in microbial cell distributions between the aqueous and solid phases imply that groundwater analysis can underestimate the total cell abundance in the aquifer by orders-of-magnitude under conditions of growth and in porous media with elevated organic carbon content. The implications of these findings for monitoring chlorinated solvent sites are discussed. PMID:25105899

  6. Vapor-phase infrared spectroscopy on solid organic compounds with a pulsed resonant photoacoustic detection scheme

    NASA Astrophysics Data System (ADS)

    Bartlome, Richard; Fischer, Cornelia; Sigrist, Markus W.

    2005-08-01

    There is a great need for a low cost and sensitive method to measure infrared spectra of solid organic compounds in the gas phase. To record such spectra, we propose an optical parametric generator-based photoacoustic spectrometer, which emits in the mid-infrared fingerprint region between 3 and 4 microns. In this system, the sample is heated in a vessel before entering a home built photoacoustic cell, where the gaseous molecules are excited by a tunable laser source with a frequency repetition rate that matches the first longitudinal resonance frequency of the photocaoustic cell. In a first phase, we have focused on low-melting point stimulants such as Nikethamide, Mephentermine sulfate, Methylephedrine, Ephedrine and Pseudoephedrine. The vapor-phase spectra of these doping substances were measured between 2800 and 3100 cm-1, where fundamental C-H stretching vibrations take place. Our spectra show notable differences with commercially available condensed phase spectra. Our scheme enables to measure very low vapor pressures of low-melting point (<160 °C) solid organic compounds. Furthermore, the optical resolution of 8 cm-1 is good enough to distinguish closely related chemical structures such as the Ephedra alkaloids Ephedrine and Methylephedrine, but doesn't allow to differentiate diastereoisomeric pairs such as Ephedrine and Pseudoephedrine, two important neurotransmitters which reveal different biological activities. Therefore, higher resolution and a system capable of measuring organic compounds with higher melting points are required.

  7. A comparison of methods to predict solid phase heats of formation of molecular energetic salts.

    PubMed

    Byrd, Edward F C; Rice, Betsy M

    2009-01-01

    In this study a variety of methods were used to compute the energies for lattice enthalpies and gas phase heats of formation of the ionic constituents used in Born-Fajans-Haber cycles to produce solid phase heats of formation of molecular ionic energetic crystals. Several quantum mechanically based or empirical approaches to calculate either the heat of formation of the ionic constituents in the gas phase (deltaH(o)f(g)) or the lattice enthalpy (deltaH(o)Lattice) were evaluated. Solid phase heats of formation calculated from combinations of deltaH(o)f(g) and deltaH(o)Lattice determined through various approaches are compared with experimental values for a series of molecular energetic salts with 1:1, 2:1 and 2:2 charge ratios. Recommendations for combinations of deltaH(o)f(g) and deltaH(o)Lattice to produce best agreement with experiment are given, along with suggestions for improvements of the methods.

  8. Solid-phase Extraction and Purification of Membrane Proteins Using a UV-modified PMMA Microfluidic Bioaffinity μSPE Device

    PubMed Central

    Battle, Katrina N.; Jackson, Joshua M.; Witek, Małgorzata A.; Hupert, Mateusz L.; Hunsucker, Sally A.; Armistead, Paul M.; Soper, Steven A.

    2014-01-01

    We present a novel microfluidic solid-phase extraction (μSPE) device for the affinity enrichment of biotinylated membrane proteins from whole cell lysates. The device offers features that address challenges currently associated with the extraction and purification of membrane proteins from whole cell lysates, including the ability to release the enriched membrane protein fraction from the extraction surface so that they are available for downstream processing. The extraction bed was fabricated in PMMA using hot embossing and was comprised of 3,600 micropillars. Activation of the PMMA micropillars by UV/O3 treatment permitted generation of surface-confined carboxylic acid groups and the covalent attachment of NeutrAvidin onto the μSPE device surfaces, which was used to affinity select biotinylated MCF-7 membrane proteins directly from whole cell lysates. The inclusion of a disulfide linker within the biotin moiety permitted release of the isolated membrane proteins via DTT incubation. Very low levels (~20 fmol) of membrane proteins could be isolated and recovered with ~89% efficiency with a bed capacity of 1.7 pmol. Western blotting indicated no traces of cytosolic proteins in the membrane protein fraction as compared to significant contamination using a commercial detergent-based method. We highlight future avenues for enhanced extraction efficiency and increased dynamic range of the μSPE device using computational simulations of different micropillar geometries to guide future device designs. PMID:24487280

  9. Report: Affinity Chromatography.

    ERIC Educational Resources Information Center

    Walters, Rodney R.

    1985-01-01

    Supports, affinity ligands, immobilization, elution methods, and a number of applications are among the topics considered in this discussion of affinity chromatography. An outline of the basic principles of affinity chromatography is included. (JN)

  10. Phase shift method to estimate solids circulation rate in circulating fluidized beds

    SciTech Connect

    Ludlow, James Christopher; Panday, Rupen; Shadle, Lawrence J.

    2013-01-01

    While solids circulation rate is a critical design and control parameter in circulating fluidized bed (CFB) reactor systems, there are no available techniques to measure it directly at conditions of industrial interest. Cold flow tests have been conducted at NETL in an industrial scale CFB unit where the solids flow has been the topic of research in order to develop an independent method which could be applied to CFBs operating under the erosive and corrosive high temperatures and pressures of a coal fired boiler or gasifier. The dynamic responses of the CFB loop to modest modulated aeration flows in the return leg or standpipe were imposed to establish a periodic response in the unit without causing upset in the process performance. The resulting periodic behavior could then be analyzed with a dynamic model and the average solids circulation rate could be established. This method was applied to the CFB unit operated under a wide range of operating conditions including fast fluidization, core annular flow, dilute and dense transport, and dense suspension upflow. In addition, the system was operated in both low and high total solids inventories to explore the influence of inventory limiting cases on the estimated results. The technique was able to estimate the solids circulation rate for all transport circulating fluidized beds when operating above upper transport velocity, U{sub tr2}. For CFB operating in the fast fluidized bed regime (i.e., U{sub g}< U{sub tr2}), the phase shift technique was not successful. The riser pressure drop becomes independent of the solids circulation rate and the mass flow rate out of the riser does not show modulated behavior even when the riser pressure drop does.

  11. Superfluid, solid, and supersolid phases of dipolar bosons in a quasi-one-dimensional optical lattice

    SciTech Connect

    Fellows, Jonathan M.; Carr, Sam T.

    2011-11-15

    We discuss a model of dipolar bosons trapped in a weakly coupled planar array of one-dimensional tubes. We consider the situation where the dipolar moments are aligned by an external field, and we find a rich phase diagram as a function of the angle of this field exhibiting quantum phase transitions between solid, superfluid, and supersolid phases. In the low energy limit, the model turns out to be identical to one describing quasi-one-dimensional superconductivity in condensed matter systems. This opens the possibility of using bosons as a quantum analog simulator of electronic systems, a scenario arising from the intricate relation between statistics and interactions in quasi-one-dimensional systems.

  12. Computation of solid/liquid phase change including free convection - Comparison with data

    NASA Technical Reports Server (NTRS)

    Schneider, G. E.

    1990-01-01

    A computational model is presented for solid/liquid phase-change energy transport including free convection fluid flow in the liquid phase. The computational model considers the velocity components of all nonliquid control volumes to be zero but fully solves the coupled mass-momentum problem within the liquid. The thermal energy model includes the entire domain and employs an enthalpy-like model and a recently developed method for handling the phase-change interface nonlinearity. Convergence studies are performed and comparisons made with experimental data for two different problems. Grid independence is achieved, and the comparison with experimental data indicates excellent quantitative prediction of the melt fraction evolution. Qualitative data are also provided as velocity vector and isotherm plots. The computational costs incurred are quite low by comparison with other models.

  13. Surface Specularity as an Indicator of Shock-induced Solid-liquid Phase Transitions in Tin

    SciTech Connect

    G. D. Stevens, S. S. Lutz, B. R. Marshall, W.D. Turley, et al.

    2007-12-01

    When highly polished metal surfaces melt upon release after shock loading, they exhibit features that suggest significant surface changes accompany the phase transition. The reflection of light from such surfaces changes from specular (pre-shock) to diffuse upon melting. Typical of this phenomenon is the loss of signal light in velocity interferometer system for any reflector (VISAR) measurements, which usually occurs at pressures high enough to melt the free surface. Unlike many other potential material phase-sensitive diagnostics (e.g., reflectometry, conductivity), that show relatively small (1%-10%) changes, the specularity of reflection provides a more sensitive and definitive (>10x) indication of the solid-liquid phase transition. Data will be presented that support the hypothesis that specularity changes indicate melt in a way that can be measured easily and unambiguously.

  14. Determination of bevantolol in human plasma by high performance liquid chromatography using solid phase extraction technique.

    PubMed

    Trung, Tran Quoc; Long, Pham Hai; Al-Abd, Ahmed M; Ku, Hyo Jeong; Lee, Ho Yoon; Hwang, Sung Joo; Kim, Kyeong Ho

    2007-07-01

    A method was developed and fully validated for the determination of bevantolol, an adrenergic-receptor blocker, in human plasma. Bevantolol and betaxolol as internal standard (I.S) were extracted from 1 mL of human plasma by solid phase extraction technique using Sep-pak silica cartridge. Chromatographic separation was accomplished under isocratic conditions using a reverse-phase C8 analytical column and mixture of dibasic ammonium phosphate (pH 5.7; 50 mM)-acetonitrile (75:25, v/v) as mobile phase, with a detection wavelength at 220 nm. The method was proved to be specific by testing six different human plasma sources. Linearity was established for the concentration ranges of 40-1600 ng/mL with correlation coefficent of 0.9995. The lower limit of quantification 40 ng/mL with precision of 10.9% as C.V%.

  15. NMR signal analysis to characterize solid, aqueous, and lipid phases in baked cakes.

    PubMed

    Le Grand, F; Cambert, M; Mariette, F

    2007-12-26

    Proton mobility was studied in molecular fractions of some model systems and of cake using a 1H nuclear magnetic resonance (NMR) relaxation technique. For cake, five spin-spin relaxation times (T2) were obtained from transverse relaxation curves: T2 (1) approximately 20 micros, T2 (2) approximately 0.2 ms, T2 (3) approximately 3 ms, T2 (4) approximately 50 ms, and T2 (2) approximately 165 ms. The faster component was attributed to the solid phase, components 2 and 3 were associated with the aqueous phase, and the two slowest components were linked to the lipid phase. After cooking, the crust contained more fat but less water than the center part of the cake. The amount of gelatinized starch was lower in the crust, and water was more mobile due to less interaction with macromolecules. This preliminary study revealed different effects of storage on the center and crust.

  16. MULTI-PHASE CFD MODELING OF A SOLID SORBENT CARBON CAPTURE SYSTEM

    SciTech Connect

    Ryan, Emily M.; Xu, Wei; DeCroix, David; Saha, Kringan; Huckaby, E. D.; Darteville, Sebastien; Sun, Xin

    2012-05-01

    Post-combustion solid sorbent carbon capture systems are being studied via computational modeling as part of the U.S. Department of Energy’s Carbon Capture Simulation Initiative (CCSI). The work focuses on computational modeling of device-scale multi-phase computational fluid dynamics (CFD) simulations for given carbon capture reactor configurations to predict flow properties, outlet compositions, temperature and pressure. The detailed outputs of the device-scale models provide valuable insight into the operation of new carbon capture devices and will help in the design and optimization of carbon capture systems. As a first step in this project we have focused on modeling a 1 kWe solid sorbent carbon capture system using the commercial CFD software ANSYS FLUENT®. Using the multi-phase models available in ANSYS FLUENT®, we are investigating the use of Eulerian-Eulerian and Eulerian-Lagrangian methods for modeling a fluidized bed carbon capture design. The applicability of the dense discrete phase method (DDPM) is being considered along with the more traditional Eulerian-Eulerian multi-phase model. In this paper we will discuss the design of the 1 kWe solid sorbent system and the setup of the DDPM and Eulerian-Eulerian models used to simulate the system. The results of the hydrodynamics in the system will be discussed and the predictions of the DDPM and Eulerian-Eulerian simulations will be compared. A discussion of the sensitivity of the model to boundary and initial conditions, computational meshing, granular pressure, and drag sub-models will also be presented.

  17. Aplication of Phase Shift Projection Moire Technique in Solid Surfaces Topographic Survey

    NASA Astrophysics Data System (ADS)

    Lino, A. C. L.; Dal Fabbro, I. M.; Enes, A. M.

    2008-04-01

    The application of projection moiré with phase shift techniques in vegetable organs surface topography survey had to step up basic procedures before reaching significant conclusions. As recommended by [1], the proposed method should be tested on virtual surfaces [1] before being carried on solid symmetric surfaces [2], followed by tests on asymmetric surfaces as fruits [3] and finally a generation of a 3D digital models of solid figures as well as of fruits [4]. In this research, identified as the step [2], tested objects included cylinders, cubes and spheres. In this sense a Ronchi grid named G1 was generated in a PC, from which other grids referred as G2, G3, and G4 were set out of phase by 1/4, 1/2 and 3/4 of period from G1. Grid G1 was then projected onto the samples surface instead of being virtually distorted, receiving the name of Gd. The difference between Gd and G1, G2, G3, and G4 followed by filtration generated the moiré fringes M1, M2, M3 and M4 respectively. Fringes are out of phase one from each other by 1/4 of period, which were processed by the Rising Sun Moiré software to produce packed phase and further on, the unpacked fringes. Final representations in gray levels as well as in contour lines showed the topography of the deformed grid Gd. Parallel line segments were projected onto moiré generated surface images to evaluate the approximation to the real surface. Line segments images were then captured by means of the ImageJ software and the corresponding curve fitting obtained. The work conclusions included the reliability of the proposed method in surveying solid figures shape.

  18. Solid-phase heavy-metal separation under unfavorable background conditions by composite membranes

    SciTech Connect

    Sengupta, S.; Sengupta, A.K.

    1995-12-31

    Disposal of sludges or treatment of soil contaminated with minor fraction (often less than 5%) of heavy metals in the solid phase in an otherwise innocuous background is a widespread problem. Selective and targeted removal of the heavy metals from the background solid phase would constitute an efficient treatment process as it would be able to reduce the volume of hazardous sludge considerably and also may make it possible for the heavy metals to be concentrated and recycled/reused. A new class of sorptive/desorptive ion-exchange composite membranes available commercially is extremely suitable for heavy metal decontamination from sludges/slurries. In this material, fine spherical beads (<100 {micro} in dia) of heavy-metal selective chelating ion-exchangers are physically enmeshed or trapped in thin sheets ({approx}0.5 mm thick) of highly porous polytetrafluoroethylene (PTFE). These composite membranes, because of their thin-sheet like physical configuration, can be easily introduced into and withdrawn from any reactor containing sludge/slurry and the target solutes can be adsorbed onto the microbeads. These membranes are not fouled by high concentration of suspended solids but retain the retain the original properties of the chelating exchangers even after use for a number of cycles. This paper explores the efficacy of the composite membrane for heavy metal decontamination under unfavorable conditions.

  19. Determination of theophylline in serum by molecularly imprinted solid-phase extraction with pulsed elution.

    PubMed

    Mullett, W M; Lai, E P

    1998-09-01

    The technique of molecular imprinting is used to produce an extensively cross-linked poly(methacrylic acid-co-ethylene dimethacrylate) material that contains theophylline as a print molecule. After Soxhlet extraction of the theophylline, binding sites are formed in the polymer with complementary size, shape, and positioning of chemical functionalities. The molecularly imprinted polymer's (MIP) high theophylline selectivity, chemical stability, and physically robust nature make it an ideal stationary-phase material in columns for HPLC separation of theophylline from other structurally related drug compounds. Mobile-phase tests confirm that a retention mechanism typical of normal-phase chromatography governs the separation, and selectivity of the MIP column can be controlled by a combination of the mobile phase and the sample solvent. Under optimal conditions, the MIP column functions like a solid-phase sorbent for theophylline extraction. Rapid elution of the bound theophylline can be accomplished in a pulsed format through injection of 20 μL of a solvent that has the proper polarity and protic nature to disrupt the electrostatic interactions and hydrogen bonding between theophylline and binding sites. A concentration detection limit of 120 ng/mL is obtained using direct UV absorption detection at 270 nm, which corresponds to a mass detection limit of 2.4 ng. This new technique, molecularly imprinted solid-phase extraction with pulsed elution (MISPE-PE), permits on-line preconcentration of theophylline from a large volume of dilute sample solution. Using a sample volume of 300 μL, a 40 ng/mL standard solution produces a detectable peak signal. Application of MISPE-PE in serum analysis further demonstrates the high capability of the MIP column to selectively isolate theophylline from other matrix components for fast, accurate determination.

  20. A convenient solid-phase method for synthesis of 3'-conjugates of oligonucleotides.

    PubMed

    Stetsenko, D A; Gait, M J

    2001-01-01

    We present a new procedure for the preparation of 3'-conjugates of oligonucleotides through solid-phase synthesis. A suitable universal solid support was readily prepared using a series of peptide-like coupling reactions to incorporate first a spacer and then an L-homoserine branching unit. The N-alpha-position of the homoserine carries an Fmoc protecting group that is removed by treatment with piperidine to liberate an amino group suitable for attachment of the conjugate (e.g., small organic molecule, fluorescent group, cholesterol, biotin, amino acid, etc.) or for assembly of a short peptide. The side-chain hydroxyl group of the homoserine carries a trityl protecting group. After TFA deprotection, the hydroxyl group acts as the site for oligonucleotide assembly. An additional spacer, such as aminohexanoyl, may be incorporated easily between the conjugate molecule and the oligonucleotide. A number of examples of synthesis of 3'-conjugates of oligonucleotides and their analogues are described that involve standard automated oligonucleotide assembly and use of commercially available materials. The linkage between oligonucleotide and 3'-conjugate is chirally pure and is stable to conventional ammonia treatment used for oligonucleotide deprotection and release from the solid support. The homoserine-functionalized solid support system represents a simple and universal route to 3'-conjugates of oligonucleotides and their derivatives.

  1. Application of solid-phase extraction to agar-supported fermentation.

    PubMed

    Le Goff, Géraldine; Adelin, Emilie; Cortial, Sylvie; Servy, Claudine; Ouazzani, Jamal

    2013-09-01

    Agar-supported fermentation (Ag-SF), a variant of solid-state fermentation, has recently been improved by the development of a dedicated 2 m(2) scale pilot facility, Platotex. We investigated the application of solid-phase extraction (SPE) to Ag-SF in order to increase yields and minimize the contamination of the extracts with agar constituents. The selection of the appropriate resin was conducted on liquid-state fermentation and Diaion HP-20 exhibited the highest recovery yield and selectivity for the metabolites of the model fungal strains Phomopsis sp. and Fusarium sp. SPE applied to Ag-SF resulted in a particular compartmentalization of the culture. The mycelium that requires oxygen to grow migrates to the top layer and formed a thick biofilm. The resin beads intercalate between the agar surface and the mycelium layer, and trap directly the compounds secreted by the mycelium through a "solid-solid extraction" (SSE) process. The resin/mycelium layer is easily recovered by scraping the surface and the target metabolites extracted by methanol. Ag-SF associated to SSE represents an ideal compromise for the production of bioactive secondary metabolites with limited economic and environmental impact.

  2. Kinetics of the aerobic biological degradation of shredded municipal solid waste in liquid phase.

    PubMed

    Liwarska-Bizukojc, Ewa; Bizukojc, Marcin; Ledakowicz, Stanislaw

    2002-04-01

    The organic fraction of municipal solid waste (OFMSW) should be utilised by means of biological methods. The biodegradation of solid wastes can be intensified owing to application of the bioreactors. Estimation of the optimum values of the organic load is one of the most important tasks for the aerobic biodegradation processes. The kinetic model of biological oxidation of the organic wastes has been presented in this paper. The experiments were carried out in batch 6-l working volume stirred tank bioreactors at constant temperature of 25 degrees C. Initial total solids have been at the levels of 15, 19, 34, 55 and 66 g l(-1). The kinetics of microbial decomposition of organic substances was described by means of an unstructured model. The satisfactory time courses for substrate chemical oxygen demand in the solid (CODs) and liquid phase (CODL) and biomass concentration (RNA) have been achieved. Also, the influence of the initial TS on the kinetics of the biodegradation process was investigated and the optimum value of initial TS for this type of processes was estimated at 34-55 g l(-1).

  3. Diversifying the solid state and lyotropic phase behavior of nonionic urea-based surfactants.

    PubMed

    Fong, Celesta; Wells, Darrell; Krodkiewska, Irena; Weerawardeena, Asoka; Booth, Jamie; Hartley, Patrick G; Drummond, Calum J

    2007-09-13

    The solid state and lyotropic phase behavior of 10 new nonionic urea-based surfactants has been characterized. The strong homo-urea interaction, which can prevent urea surfactants from forming lyotropic liquid crystalline phases, has been ameliorated through the use of isoprenoid hydrocarbon tails such as phytanyl (3,7,11,15-tetramethyl-hexadecyl) and hexahydrofarnesyl (3,7,11-trimethyl-dodecyl) or the oleyl chain (cis-octadec-9-enyl). Additionally, the urea head group was modified by attaching either a hydroxy alkyl (short chain alcohol) moiety to one of the nitrogens of the urea or by effectively "doubling" the urea head group by replacing it with a biuret head group. The solid state phase behavior, including the liquid crystal-isotropic liquid, polymorphic, and glass transitions, is interpreted in terms of molecular geometries and probable hydrogen-bonding interactions. Four of the modified urea surfactants displayed ordered lyotropic liquid crystalline phases that were stable in excess water at both room and physiological temperatures, namely, 1-(2-hydroxyethyl)-1-oleyl urea (oleyl 1,1-HEU) with a 1D lamellar phase (Lalpha), 1-(2-hydroxyethyl)-3-phytanyl urea (Phyt 1,3-HEU) with a 2D inverse hexagonal phase (HII), and 1-(2-hydroxyethyl)-1-phytanyl urea (Phyt 1,1-HEU) and 1-(2-hydroxyethyl)-3-hexahydrofarnesyl urea (Hfarn 1,3-HEU) with a 3D bicontinuous cubic phase (QII). Phyt 1,1-HEU exhibited rich mesomorphism (QII1, QII2, Lalpha, LU, and HII), as did one other surfactant, oleyl 1,3-HEU (QII1, QII2, Lalpha, LU, and HII), in the study group. LU is an unusual phase which is mobile and isotropic but possesses shear birefringence, and has been very tentatively assigned as an inverse sponge phase. Three other surfactants exhibited a single lyotropic liquid crystalline phase, either Lalpha or HII, at temperatures >50 degrees C. The 10 new surfactants are compared with other recently reported nonionic urea surfactants. Structure-property correlations are examined for

  4. Solid/liquid phase diagram of the ammonium sulfate/glutaric acid/water system.

    PubMed

    Beyer, Keith D; Pearson, Christian S; Henningfield, Drew S

    2013-05-01

    We have studied the low temperature phase diagram and water activities of the ammonium sulfate/glutaric acid/water system using differential scanning calorimetry, infrared spectroscopy of thin films, and a new technique: differential scanning calorimetry-video microscopy. Using these techniques, we have determined that there is a temperature-dependent kinetic effect to the dissolution of glutaric acid in aqueous solution. We have mapped the solid/liquid ternary phase diagram, determined the water activities based on the freezing point depression, and determined the ice/glutaric acid phase boundary as well as the ternary eutectic composition and temperature. We have also modified our glutaric acid/water binary phase diagram previously published based on these new results. We compare our results for the ternary system to the predictions of the Extended AIM Aerosol Thermodynamics Model (E-AIM), and find good agreement for the ice melting points in the ice primary phase field of this system; however, significant differences were found with respect to phase boundaries, concentration and temperature of the ternary eutectic, and glutaric acid dissolution. PMID:23544733

  5. Direct observations of welding-induced solid-state phase transformations

    SciTech Connect

    Elmer, J.W.; Wong, J.; Waide, P.A.

    1994-12-31

    A new diagnostic tool that uses time-resolved x-ray diffraction (TRXRD) for in-situ, spatially resolved, phase identification around a weld is presented for the purpose of mapping the location of phase fields during welding. In this investigation, TRXRD experiments were conducted at the Stanford Sychrotron Radiation Laboratory where a high-intensity tunable synchrotron x-ray `probe` was available. The high spatial resolution of the x-ray probe (1mm) allowed precise mapping of specific phase fields around the weld, while the high intensity of the beam (10{sup 11} photons/s) yielded high signal-to-noise ratio of the diffracted x-rays. These characteristics enabled the crystal structure to be characterized during a 1-s x-ray integration time, thus providing real-time data to be gathered about welding-induced phase transformations. Experiments were performed on unalloyed Grade 4 titanium (Ti, 0.28%Fe, 0.38%O), which has an allotropic phase transition that occurs at 922{degrees}C, where the low temperature hcp phase transforms to the high temperature bcc phase. Welds were made using a semi-automatic tungsten inert gas procedure to establish a quasisteady-state thermal profile on 4.5 in. diameter titanium bar, which was rotated at a speed of 0.5 rpm beneath a 3.5 kW arc. Characteristic hcp, bcc, and liquid diffraction peaks were measured along x-ray probe scans traveling from the base metal through the heat-affected zone and into the weld pool, respectively. The results of this study clearly demonstrate the feasibility of using TRXRD for in-situ investigations of welding-induced phase transformations, thus allowing verification of welding models, the creation of transformation diagrams during rapid thermal cycling of materials, and the ability for real-time investigations of the nucleation and growth behavior of solid-state phase transformations.

  6. Serial studies on the affinity and heterogeneity of human autoantibodies to thyroglobulin.

    PubMed Central

    Devey, M E; Bleasdale-Barr, K M; McLachlan, S M; Bradbury, J; Clark, F; Young, E T

    1989-01-01

    The functional affinity and heterogeneity of autoantibodies to thyroglobulin (Tg) were measured by an IgG subclass-specific solid-phase competition ELISA in patients with autoimmune thyroid disease. High-affinity IgG1 and IgG4 antibodies formed the major anti-Tg response. Both titre and affinity of IgG3 and IgG2 anti-Tg were generally low but in some Hashimoto's disease patients high-affinity IgG2 anti-Tg were found and IgG2 anti-Tg, unlike those of other subclasses, showed very restricted heterogeneity. The affinity of IgG4 anti-Tg was similar in patients with thyroid disease and their clinically euthyroid (normal) relatives. In contrast, a progressive increase in IgG1 anti-Tg affinity was seen in clinically euthyroid individuals compared with their relatives with thyroid disease and high titred Hashimoto's disease patients, suggesting that either rising titres of high affinity IgG1 anti-Tg or affinity maturation of IgG1 anti-Tg may be indicative of impending hypothyroidism. PMID:2776357

  7. Iron solid-phase differentiation along a redox gradient in basaltic soils

    NASA Astrophysics Data System (ADS)

    Thompson, Aaron; Rancourt, Denis G.; Chadwick, Oliver A.; Chorover, Jon

    2011-01-01

    Iron compounds in soil are multifunctional, providing physical structure, ion sorption sites, catalytic reaction-centers, and a sink for respiratory electrons. Basaltic soils contain large quantities of iron that reside in different mineral and organic phases depending on their age and redox status. We investigated changes in soil iron concentration and its solid-phase speciation across a single-aged (400 ky) lava flow subjected to a gradient in precipitation (2200-4200 mm yr -1) and hence redox history. With increasing rainfall and decreasing Eh, total Fe decreased from about 25% to <1% of the soil mass. Quantitative speciation of soil solid-phase iron was constrained by combining 57Fe Mössbauer spectroscopy (MBS) at 295 and 4.2 K with powder X-ray diffraction, selective chemical extractions, and magnetic susceptibility measurements. This approach allowed us to partition iron into (1) nanoparticulate and microcrystalline Fe III-(oxy)hydroxides, (2) microcrystalline and bulk Fe III-oxides, (3) organic/silicate bound Fe III, and (4) ferrous iron. The Fe III-(oxy)hydroxide fraction dominated solid-phase Fe, exhibiting a crystallinity continuum based on magnetic ordering temperature. The continuum extended from well-ordered microcrystalline goethite through nanocrystalline Fe III-(oxy)hydroxides to a nano Fe III-(oxy)hydroxide phase of extremely low crystallinity. Magnetic susceptibility was correlated ( R2 = 0.77) with Fe III-oxide concentration, consistent with a contribution of maghemite to the otherwise hematite dominated Fe-oxide fraction. The Fe III-(oxy)hydroxide fraction of total Fe decreased with increasing rainfall and was replaced by corresponding increase in the organic/silicate Fe III fraction. The crystallinity of the Fe III-(oxy)hydroxides also decreased with increasing rainfall and leaching, with the most disordered members of the crystallinity continuum, the nano Fe III-(oxy)hydroxides, gaining proportional abundance in the wetter sites. This finding

  8. A Two-Phase Solid/Fluid Model for Dense Granular Flows Including Dilatancy Effects

    NASA Astrophysics Data System (ADS)

    Mangeney, Anne; Bouchut, Francois; Fernandez-Nieto, Enrique; Narbona-Reina, Gladys

    2015-04-01

    We propose a thin layer depth-averaged two-phase model to describe solid-fluid mixtures such as debris flows. It describes the velocity of the two phases, the compression/dilatation of the granular media and its interaction with the pore fluid pressure, that itself modifies the friction within the granular phase (Iverson et al., 2010). The model is derived from a 3D two-phase model proposed by Jackson (2000) based on the 4 equations of mass and momentum conservation within the two phases. This system has 5 unknowns: the solid and fluid velocities, the solid and fluid pressures and the solid volume fraction. As a result, an additional equation inside the mixture is necessary to close the system. Surprisingly, this issue is inadequately accounted for in the models that have been developed on the basis of Jackson's work (Bouchut et al., 2014). In particular, Pitman and Le replaced this closure simply by imposing an extra boundary condition at the surface of the flow. When making a shallow expansion, this condition can be considered as a closure condition. However, the corresponding model cannot account for a dissipative energy balance. We propose here an approach to correctly deal with the thermodynamics of Jackson's equations. We close the mixture equations by a weak compressibility relation involving a critical density, or equivalently a critical pressure. Moreover, we relax one boundary condition, making it possible for the fluid to escape the granular media when compression of the granular mass occurs. Furthermore, we introduce second order terms in the equations making it possible to describe the evolution of the pore fluid pressure in response to the compression/dilatation of the granular mass without prescribing an extra ad-hoc equation for the pore pressure. We prove that the energy balance associated with this Jackson closure is dissipative, as well as its thin layer associated model. We present several numerical tests for the 1D case that are compared to the

  9. A Two-Phase Solid/Fluid Model for Dense Granular Flows Including Dilatancy Effects

    NASA Astrophysics Data System (ADS)

    Mangeney, A.; Bouchut, F.; Fernández-Nieto, E. D.; Narbona-Reina, G.; Kone, E. H.

    2014-12-01

    We propose a thin layer depth-averaged two-phase model to describe solid-fluid mixtures such as debris flows. It describes the velocity of the two phases, the compression/dilatation of the granular media and its interaction with the pore fluid pressure, that itself modifies the friction within the granular phase (Iverson et al., 2010). The model is derived from a 3D two-phase model proposed by Jackson (2000) based on the 4 equations of mass and momentum conservation within the two phases. This system has 5 unknowns: the solid and fluid velocities, the solid and fluid pressures and the solid volume fraction. As a result, an additional equation inside the mixture is necessary to close the system. Surprisingly, this issue is inadequately accounted for in the models that have been developed on the basis of Jackson's work (Bouchut et al., 2014). In particular, Pitman and Le replaced this closure simply by imposing an extra boundary condition at the surface of the flow. When making a shallow expansion, this condition can be considered as a closure condition. However, the corresponding model cannot account for a dissipative energy balance. We propose here an approach to correctly deal with the thermodynamics of Jackson's equations. We close the mixture equations by a weak compressibility relation involving a critical density, or equivalently a critical pressure. Moreover, we relax one boundary condition, making it possible for the fluid to escape the granular media when compression of the granular mass occurs. Furthermore, we introduce second order terms in the equations making it possible to describe the evolution of the pore fluid pressure in response to the compression/dilatation of the granular mass without prescribing an extra ad-hoc equation for the pore pressure. We prove that the energy balance associated with this Jackson closure is dissipative, as well as its thin layer associated model. We present several numerical tests for the 1D case that are compared to the

  10. Modeling of dilute two-phase multispecies solid/gas flows

    SciTech Connect

    Doss, E.D.; Srinivasan, M.G.; Raptis, A.C.

    1986-06-01

    The report gives a detailed description of the analytical modeling that underlies the numerical code for predicting the flow of dilute solid/gas flows in pipes. The model is two-phase multispecies. Particles of one size are treated as one species and the equations of particle dynamics include terms to account for momentum transfer between species and the wall friction on each species of particles. New expressions for particle/particle interaction and wall friction for multispecies flow are derived. Results of parametric studies based on the new expressions are described. The predictions of this model for gas/powder flow through a venturi are compared with experimental measurements. The model's capability for predicting the flow in Argonne's Solid/Gas Flow Test Facility will be the subject of a companion report. 26 refs., 16 figs.

  11. Liquid-solid phase transition of hydrogen and deuterium in silica aerogel

    NASA Astrophysics Data System (ADS)

    Van Cleve, E.; Worsley, M. A.; Kucheyev, S. O.

    2014-10-01

    Behavior of hydrogen isotopes confined in disordered low-density nanoporous solids remains essentially unknown. Here, we use relaxation calorimetry to study freezing and melting of H2 and D2 in an ˜85%-porous base-catalyzed silica aerogel. We find that liquid-solid transition temperatures of both isotopes inside the aerogel are depressed. The phase transition takes place over a wide temperature range of ˜4 K and non-trivially depends on the liquid filling fraction, reflecting the broad pore size distribution in the aerogel. Undercooling is observed for both H2 and D2 confined inside the aerogel monolith. Results for H2 and D2 are extrapolated to tritium-containing hydrogens with the quantum law of corresponding states.

  12. Random phase approximation correlation energy using a compact representation for linear response functions: application to solids

    NASA Astrophysics Data System (ADS)

    Kaoui, Fawzi; Rocca, Dario

    2016-01-01

    A new approach was recently presented to compute correlation energies within the random phase approximation using Lanczos chains and an optimal basis set (Rocca 2014 J. Chem. Phys. 140 18A501). This novel method avoids the explicit calculation of conduction states and represents linear response functions on a compact auxiliary basis set obtained from the diagonalization of an approximate dielectric matrix that contains only the kinetic energy contribution. Here, we extend this formalism, originally implemented for molecular systems, to treat periodic solids. In particular, the approximate dielectric matrix used to build the auxiliary basis set is generalized to avoid unphysical negative gaps, that make the model inefficient. The numerical convergence of the method is discussed and the accuracy is demonstrated considering a set including three covalently bonded (C, Si, and SiC) and three weakly bonded (Ne, Ar, and Kr) solids.

  13. HLA antibody detection with solid phase assays: great expectations or expectations too great?

    PubMed

    Gebel, H M; Bray, R A

    2014-09-01

    Alloantibodies directed against HLA antigens, are a barrier to long-term solid organ allograft survival. The clinical impact of preformed, donor-directed HLA alloantibodies range from acceptable risk to unequivocal contraindication for organ transplantation. HLA antibodies are key factors that limit patient access to donor organs. Serological methods were once the only approach to identify HLA antigens and antibodies. Limitations in these technologies led to the development of solid phase approaches. In the early 1990s, the development of the polymerase chain reaction enabled DNA-based HLA antigen testing to be performed. By the mid-1990s, microparticle-based technology that utilized flow cytometry for analysis was developed to detect both classes I and II HLA antibodies. These methodologies revolutionized clinical histocompatibility testing. The strengths and weaknesses of these assays are described in detail in this review.

  14. Phase transformations and the spectral reflectance of solid sulfur - Can metastable sulfur allotropes exist on Io?

    NASA Technical Reports Server (NTRS)

    Moses, Julianne I.; Nash, Douglas B.

    1991-01-01

    Laboratory investigations have been conducted on the effects of variations in sulfur sample histories on their solid-state transformation rate and the corresponding spectral variation of freshly frozen sulfur. The temporal variations in question may be due to differences in the amount and type of metastable allotropes present in the sulfur after solidification, as well as to the physics of the phase-transformation process itself. The results obtained are pertinent to the physical behavior and spectral variation of such freshly solidified sulfur as may exist on the Jupiter moon Io; this would initially solidify into a glassy solid or monoclinic crystalline lattice, then approach ambient dayside temperatures. Laboratory results imply that the monoclinic or polymeric allotropes can in these circumstances be maintained, and will take years to convert to the stable orthorhombic crystalline form.

  15. Liquid–solid phase transition of hydrogen and deuterium in silica aerogel

    SciTech Connect

    Van Cleve, E.; Worsley, M. A.; Kucheyev, S. O.

    2014-10-28

    Behavior of hydrogen isotopes confined in disordered low-density nanoporous solids remains essentially unknown. Here, we use relaxation calorimetry to study freezing and melting of H{sub 2} and D{sub 2} in an ∼85%-porous base-catalyzed silica aerogel. We find that liquid–solid transition temperatures of both isotopes inside the aerogel are depressed. The phase transition takes place over a wide temperature range of ∼4 K and non-trivially depends on the liquid filling fraction, reflecting the broad pore size distribution in the aerogel. Undercooling is observed for both H{sub 2} and D{sub 2} confined inside the aerogel monolith. Results for H{sub 2} and D{sub 2} are extrapolated to tritium-containing hydrogens with the quantum law of corresponding states.

  16. Explosive ordnance detection in land and water environments with solid phase extraction/ion mobility spectrometry

    NASA Astrophysics Data System (ADS)

    Chambers, William B.; Phelan, James M.; Rodacy, Philip J.; Reber, Steven; Woodfin, Ronald L.

    1999-08-01

    The qualitative and quantitative determination of nitroaromatic compounds such as trinitrotoluene (TNT) and dinitrotoluene (DNT) in water and soil has applications to environmental remediation and the detection of buried military ordnance. Recent results of laboratory and field test have shown that trace level concentrations of these compounds can be detected in water, soil, and solid gas samples taken from the vicinity of submerged or buried ordnance using specialized sampling and signal enhancement techniques. Solid phase micro-extraction methods have been combined with Ion Mobility Spectroscopy to provide rapid, sub-parts-per-billion analysis of these compounds. In this paper, we will describe the gas. These sampling systems, when combined with field-portable IMS, are being developed as a means of classifying buried or submerged objects as explosive ordnance.

  17. A Facile Solid-Phase Route to Renewable Aromatic Chemicals from Biobased Furanics.

    PubMed

    Thiyagarajan, Shanmugam; Genuino, Homer C; van der Waal, Jan C; de Jong, Ed; Weckhuysen, Bert M; van Haveren, Jacco; Bruijnincx, Pieter C A; van Es, Daan S

    2016-01-22

    Renewable aromatics can be conveniently synthesized from furanics by introducing an intermediate hydrogenation step in the Diels-Alder (DA) aromatization route, to effectively block retro-DA activity. Aromatization of the hydrogenated DA adducts requires tandem catalysis, using a metal-based dehydrogenation catalyst and solid acid dehydration catalyst in toluene. Herein it is demonstrated that the hydrogenated DA adducts can instead be conveniently converted into renewable aromatics with up to 80% selectivity in a solid-phase reaction with shorter reaction times using only an acidic zeolite, that is, without solvent or dehydrogenation catalyst. Hydrogenated adducts from diene/dienophile combinations of (methylated) furans with maleic anhydride are efficiently converted into renewable aromatics with this new route. The zeolite H-Y was found to perform the best and can be easily reused after calcination. PMID:26684008

  18. A solid phase assay for topoisomerase I interfacial poisons and catalytic inhibitors.

    PubMed

    Cyril, Vidusha; Muller, Mark T

    2012-02-15

    We report a mechanism-based screening technique to rapidly identify eukaryotic topoisomerase I targeting agents. The method is based on genetic tagging of topoisomerase I to immobilize the enzyme on a solid surface in a microtiter well format. DNA is added to the wells, and retained DNA is detected by Pico Green fluorescence. Compounds that result in an increase in Pico Green staining represent potential topoisomerase interfacial poisons, whereas those that reduce fluorescence report catalytic inhibitors; therefore, the solid phase assay represents a "bimodal" readout that reveals mechanisms of action. The method has been demonstrated to work with known interfacial poisons and catalytic inhibitors. This method is rapid, robust, economical, and scalable for large library screens. PMID:22214881

  19. Analysis of ecologically relevant pharmaceuticals in wastewater and surface water using selective solid phase extraction and UPLC/MS/MS

    EPA Science Inventory

    A rapid and sensitive method has been developed for the analysis of 48 human prescription active pharmaceutical ingredients (APIs) and 6 metabolites of interest, utilizing selective solid-phase extraction (SPE) and ultra performance liquid chromatography in combination with tripl...

  20. Phase-field model of solid-liquid phase transition with density difference and latent heat in velocity and elastic fields.

    PubMed

    Takae, Kyohei; Onuki, Akira

    2011-04-01

    We present a phase-field model of solid-liquid transitions with inhomogeneous temperature in one-component systems, including hydrodynamics and elasticity. Our model can describe plastic deformations at large elastic strains. We use it to investigate the melting of a solid domain, accounting for the latent heat effect, where there appears a velocity field in liquid and an elastic field in solid. We present simulation results in two dimensions for three cases of melting. First, a solid domain is placed on a heated wall, which melts mostly near the solid-liquid-wall contact region. Second, a solid domain is suspended in a warmer liquid under shear flow, which rotates as a whole because of elasticity and melts gradually. Cooling of the surrounding liquid is accelerated by convection. Third, a solid rod is under high compression in liquid, where slips appear from the solid-liquid interface, leading to a plastic deformation. Subsequently, melting starts in the plastically deformed areas, eventually resulting in the fracture of the rod into pieces. In these phase-transition processes, the interface temperature is kept nearly equal to the coexisting temperature T(cs)(p) away from the heated wall, but this local equilibrium is not attained near the the contact region. We also examine a first-order liquid-liquid phase transition under heating from a boundary in one-component liquids.

  1. Multivariate Quantification of the Solid State Phase Composition of Co-Amorphous Naproxen-Indomethacin.

    PubMed

    Beyer, Andreas; Grohganz, Holger; Löbmann, Korbinian; Rades, Thomas; Leopold, Claudia S

    2015-10-27

    To benefit from the optimized dissolution properties of active pharmaceutical ingredients in their amorphous forms, co-amorphisation as a viable tool to stabilize these amorphous phases is of both academic and industrial interest. Reports dealing with the physical stability and recrystallization behavior of co-amorphous systems are however limited to qualitative evaluations based on the corresponding X-ray powder diffractograms. Therefore, the objective of the study was to develop a quantification model based on X-ray powder diffractometry (XRPD), followed by a multivariate partial least squares regression approach that enables the simultaneous determination of up to four solid state fractions: crystalline naproxen, γ-indomethacin, α-indomethacin as well as co-amorphous naproxen-indomethacin. For this purpose, a calibration set that covers the whole range of possible combinations of the four components was prepared and analyzed by XRPD. In order to test the model performances, leave-one-out cross validation was performed and revealed root mean square errors of validation between 3.11% and 3.45% for the crystalline molar fractions and 5.57% for the co-amorphous molar fraction. In summary, even four solid state phases, involving one co-amorphous phase, can be quantified with this XRPD data-based approach.

  2. Determination of amphetamines in hair by integrating sample disruption, clean-up and solid phase derivatization.

    PubMed

    Argente-García, A; Moliner-Martínez, Y; Campíns-Falcó, P; Verdú-Andrés, J; Herráez-Hernández, R

    2016-05-20

    The utility of matrix solid phase dispersion (MSPD) for the direct analysis of amphetamines in hair samples has been evaluated, using liquid chromatography (LC) with fluorescence detection and precolumn derivatization. The proposed approach is based on the employment of MSPD for matrix disruption and clean-up, followed by the derivatization of the analytes onto the dispersant-sample blend. The fluorogenic reagent 9-fluorenylmethyl chloroformate (FMOC) has been used for derivatization. Different conditions for MSPD, analyte purification and solid phase derivatization have been tested, using amphetamine (AMP), methamphetamine (MET), ephedrine (EPE) and 3,4-methylenedioxymethamphetamine (MDMA) as model compounds. The results have been compared with those achieved by using ultrasound-assisted alkaline digestion and by MSPD combined with conventional solution derivatization. On the basis of the results obtained, a methodology is proposed for the analysis of amphetamines in hair which integrates sample disruption, clean-up and derivatization using a C18 phase. Improved sensitivity is achieved with respect to that obtained by the alkaline digestion or by the MSPD followed by solution derivatization methods. The method can be used for the quantification of the tested amphetamines within the 2.0-20.0ng/mg concentration interval, with limits of detection (LODs) of 0.25-0.75ng/mg. The methodology is very simple and rapid (the preparation of the sample takes less than 15min). PMID:27108048

  3. Evaluation of clean solid phases for extraction of nitroaromatics and nitramines from water. Special report

    SciTech Connect

    Jenkins, T.F.; Thorne, P.G.; Myers, K.F.; McCormick, E.F.; Parker, D.E.

    1995-09-01

    Salting-out solvent extraction (SOE) was compared with cartridge and membrane solid-phase extraction (SPE) for preconcentration of nitroaromatics, nitramines, and aminonitroaromatics prior to determination by reversed-phase high-performance liquid chromatography. The solid phases used were manufacturer-cleaned materials, Porapak RDX for the cartridge method and Empore SDB-RPS for the membrane method. Thirty-three groundwater samples from the Naval Surface Warfare Center, Crane, Indiana, were analyzed using the direct analysis protocol specified in SW846 Method 8330, and the results were compared with analyses conducted after preconcentration using SOE with acetonitrile, cartridge-based SPE, and membrane-based SPE. For high-concentration samples, analytical results from the three preconcentration techniques were compared with results from the direct analysis protocol; good recovery of all target analytes was achieved by all three pre-concentration methods. For low-concentration samples, results from the two SPE methods were correlated with results from the SOE method; very similar data was obtained by the SOE and SPE methods, even at concentrations well below 1 microgram/L.

  4. Determination of amphetamines in hair by integrating sample disruption, clean-up and solid phase derivatization.

    PubMed

    Argente-García, A; Moliner-Martínez, Y; Campíns-Falcó, P; Verdú-Andrés, J; Herráez-Hernández, R

    2016-05-20

    The utility of matrix solid phase dispersion (MSPD) for the direct analysis of amphetamines in hair samples has been evaluated, using liquid chromatography (LC) with fluorescence detection and precolumn derivatization. The proposed approach is based on the employment of MSPD for matrix disruption and clean-up, followed by the derivatization of the analytes onto the dispersant-sample blend. The fluorogenic reagent 9-fluorenylmethyl chloroformate (FMOC) has been used for derivatization. Different conditions for MSPD, analyte purification and solid phase derivatization have been tested, using amphetamine (AMP), methamphetamine (MET), ephedrine (EPE) and 3,4-methylenedioxymethamphetamine (MDMA) as model compounds. The results have been compared with those achieved by using ultrasound-assisted alkaline digestion and by MSPD combined with conventional solution derivatization. On the basis of the results obtained, a methodology is proposed for the analysis of amphetamines in hair which integrates sample disruption, clean-up and derivatization using a C18 phase. Improved sensitivity is achieved with respect to that obtained by the alkaline digestion or by the MSPD followed by solution derivatization methods. The method can be used for the quantification of the tested amphetamines within the 2.0-20.0ng/mg concentration interval, with limits of detection (LODs) of 0.25-0.75ng/mg. The methodology is very simple and rapid (the preparation of the sample takes less than 15min).

  5. Solid phase catalysts and reagents. Final technical report, July 1, 1977-December 31, 1983

    SciTech Connect

    Regen, S.L.

    1983-12-01

    Research supported under this grant for the period 1/1/80-12/31/83 has involved six major areas: (1) defining polymer structure-activity relationships in triphase catalytic systems, (2) developing polyether- and polyamide-based catalysts for practical organic synthesis, (3) establishing new synthetic entries into macrolides based on triphase and phase-transfer catalytic principles, (4) introducing new polymeric and monomeric mercury reagents for use in organic synthesis, (5) clarifying and quantifying kinetic isolation within cross-linked polystyrene, and (6) elucidating the kinetic and mechanistic features of the hydrolysis of organic halides in aqueous - liquid organic two phase systems. Detailed reports are presented for the six areas. For the period 7/1/77-12/31/79 brief summaries are presented for the following areas: (1) insolubilized hexamethylphosphoramide as a solid solvent; (2) triphase catalysis, consideration of catalyst and experimental conditions for simple nucleophilic displacement; (3) selectivity features of polystrene-based triphase catalysts; (4) evidence for an S/sub N//sup 1/ reaction occurring at a toluene-water interface; (5) solid phase cosolvents - triphase catalytic hydrolysis of 1-bromoadamantane; (6) consideration of the role of stirring and catalyst efficiency of polystyrene-based triphase catalysts. 24 references.

  6. Process for forming a homogeneous oxide solid phase of catalytically active material

    DOEpatents

    Perry, Dale L.; Russo, Richard E.; Mao, Xianglei

    1995-01-01

    A process is disclosed for forming a homogeneous oxide solid phase reaction product of catalytically active material comprising one or more alkali metals, one or more alkaline earth metals, and one or more Group VIII transition metals. The process comprises reacting together one or more alkali metal oxides and/or salts, one or more alkaline earth metal oxides and/or salts, one or more Group VIII transition metal oxides and/or salts, capable of forming a catalytically active reaction product, in the optional presence of an additional source of oxygen, using a laser beam to ablate from a target such metal compound reactants in the form of a vapor in a deposition chamber, resulting in the deposition, on a heated substrate in the chamber, of the desired oxide phase reaction product. The resulting product may be formed in variable, but reproducible, stoichiometric ratios. The homogeneous oxide solid phase product is useful as a catalyst, and can be produced in many physical forms, including thin films, particulate forms, coatings on catalyst support structures, and coatings on structures used in reaction apparatus in which the reaction product of the invention will serve as a catalyst.

  7. Two-phase anaerobic digestion within a solid waste/wastewater integrated management system

    SciTech Connect

    De Gioannis, G.; Diaz, L.F.; Muntoni, A. Pisanu, A.

    2008-07-01

    A two-phase, wet anaerobic digestion process was tested at laboratory scale using mechanically pre-treated municipal solid waste (MSW) as the substrate. The proposed process scheme differs from others due to the integration of the MSW and wastewater treatment cycles, which makes it possible to avoid the recirculation of process effluent. The results obtained show that the supplying of facultative biomass, drawn from the wastewater aeration tank, to the solid waste acidogenic reactor allows an improvement of the performance of the first phase of the process which is positively reflected on the second one. The proposed process performed successfully, adopting mesophilic conditions and a relatively short hydraulic retention time in the methanogenic reactor, as well as high values of organic loading rate. Significant VS removal efficiency and biogas production were achieved. Moreover, the methanogenic reactor quickly reached optimal conditions for a stable methanogenic phase. Studies conducted elsewhere also confirm the feasibility of integrating the treatment of the organic fraction of MSW with that of wastewater.

  8. Solid-liquid phase equilibria from free-energy perturbation calculations

    NASA Astrophysics Data System (ADS)

    Angioletti-Uberti, Stefano; Asta, Mark; Finnis, Mike W.; Lee, P. D.

    2008-10-01

    A method for calculating free-energy differences based on a free-energy perturbation (FEP) formalism in an alloy system described by two different Hamiltonians is reported. The intended application is the calculation of solid-liquid phase equilibria in alloys with the accuracy of first-principles electronic density-functional theory (DFT). For this purpose free energies are derived with a classical interatomic potential, and FEP calculations are used to compute corrections to these reference values. For practical applications of this approach, due to the relatively high computational cost of DFT calculations, it is critical that the FEP calculations converge rapidly in terms of the number of samples used to estimate relevant ensemble averages. This issue is investigated in the current study employing two classical interatomic-potential models for Ni-Cu. These models yield differences in predicted phase-boundary temperatures of approximately 100 K, comparable to those that might be expected between a DFT Hamiltonian and a well-fit classical potential. We show that for pure elements the FEP calculations converge rapidly with the number of samples, yielding free-energy differences converged to within a fraction of a meV/atom in a few dozen energy calculations. For a concentrated equiatomic alloy similar precision requires roughly a hundred samples. The results suggest that the proposed methodology could provide a computationally tractable framework for calculating solid-liquid phase equilibria in concentrated alloys with DFT accuracy.

  9. Solid state phase equilibria and intermetallic compounds of the Al-Cr-Ho system

    SciTech Connect

    Pang, Mingjun; Zhan, Yongzhong; Du, Yong

    2013-02-15

    The solid state phase equilibria of the Al-Cr-Ho ternary system at 500 Degree-Sign C were experimentally investigated. The phase relations at 500 Degree-Sign C are governed by 14 three-phase regions, 29 two-phase regions and 15 single-phase regions. The existences of 10 binary compounds and 2 ternary phases have been confirmed. Al{sub 11}Cr{sub 2}, Al{sub 11}Cr{sub 4} and Al{sub 17}Ho{sub 2} were not found at 500 Degree-Sign C. Crystal structures of Al{sub 9}Cr{sub 4} and Al{sub 8}Cr{sub 4}Ho were determined by the Rietveld X-ray powder data refinement. Al{sub 9}Cr{sub 4} was found to exhibit cubic structure with space group I4-bar 3m (no. 217) and lattice parameters a=0.9107(5) nm. Al{sub 8}Cr{sub 4}Ho crystallizes in ThMn{sub 12} structure type with space group I4/mmm (no. 139) and lattice parameters a=0.8909(4) nm, c=0.5120(5) nm. It is concluded that the obtained Al{sub 4}Cr phase in this work should be {mu}-Al{sub 4}Cr by comparing with XRD pattern of the hexagonal {mu}-Al{sub 4}Mn compound. - Graphical abstract: The solid state phase equilibria of the Al-Cr-Ho ternary system at 500 Degree-Sign C. Highlights: Black-Right-Pointing-Pointer Al-Cr-Ho system has been investigated. Black-Right-Pointing-Pointer Al{sub 9}Cr{sub 4} has cubic structure with space group I4-bar 3m. Black-Right-Pointing-Pointer Al{sub 8}Cr{sub 4}Ho crystallizes in ThMn{sub 12} type with space group I4/mmm. Black-Right-Pointing-Pointer Al{sub 4}Cr phase is {mu}-type at 500 Degree-Sign C.

  10. Total enthalpy-based lattice Boltzmann method with adaptive mesh refinement for solid-liquid phase change

    NASA Astrophysics Data System (ADS)

    Huang, Rongzong; Wu, Huiying

    2016-06-01

    A total enthalpy-based lattice Boltzmann (LB) method with adaptive mesh refinement (AMR) is developed in this paper to efficiently simulate solid-liquid phase change problem where variables vary significantly near the phase interface and thus finer grid is required. For the total enthalpy-based LB method, the velocity field is solved by an incompressible LB model with multiple-relaxation-time (MRT) collision scheme, and the temperature field is solved by a total enthalpy-based MRT LB model with the phase interface effects considered and the deviation term eliminated. With a kinetic assumption that the density distribution function for solid phase is at equilibrium state, a volumetric LB scheme is proposed to accurately realize the nonslip velocity condition on the diffusive phase interface and in the solid phase. As compared with the previous schemes, this scheme can avoid nonphysical flow in the solid phase. As for the AMR approach, it is developed based on multiblock grids. An indicator function is introduced to control the adaptive generation of multiblock grids, which can guarantee the existence of overlap area between adjacent blocks for information exchange. Since MRT collision schemes are used, the information exchange is directly carried out in the moment space. Numerical tests are firstly performed to validate the strict satisfaction of the nonslip velocity condition, and then melting problems in a square cavity with different Prandtl numbers and Rayleigh numbers are simulated, which demonstrate that the present method can handle solid-liquid phase change problem with high efficiency and accuracy.

  11. Mechanistic understanding of calcium-phosphonate solid dissolution and scale inhibitor return behavior in oilfield reservoir: formation of middle phase.

    PubMed

    Zhang, Ping; Shen, Dong; Ruan, Gedeng; Kan, Amy T; Tomson, Mason B

    2016-08-01

    Phosphonates are an important class of mineral scale inhibitors used for oilfield scale control. By injecting the phosphonate into an oilfield reservoir, calcium-phosphonate precipitate will form and subsequently release the phosphonate into produced water for scale control. In this study, a systematic procedure is developed to mechanistically characterize an acidic calcium-phosphonate amorphous material that is later developed into a middle phase and eventually a crystalline phase. The phosphonate used in this study is diethylenetriamine pentakis (methylene phosphonic acid) (DTPMP). An amorphous calcium-DTPMP solid is precipitated by mixing a calcium-containing solution with a DTPMP solution. The stoichiometry of this initially formed solid can be experimentally confirmed via a static dissolution test. Following another dynamic development test, two additional Ca-DTPMP solid phases, i.e., a middle phase and a crystalline phase have been observed. Electron microscopy and X-ray diffraction were employed to characterize the morphology and crystallinity of different Ca-DTPMP solids of interest. Evidently, the dynamic brine flushing of the Ca-DTPMP solid developed the initially amorphous material into a middle phase solid with an amorphous/microcrystalline structure and eventually into a crystalline material. Furthermore, a dissolution characterization study was carried out to determine the solubility product of the middle phase solid at different conditions. The obtained mechanistic understanding of the Ca-DTPMP solid related to precipitation chemistry, dissolution behavior and phase transition is critical to elucidate oilfield DTPMP return data and more importantly, can optimize the oilfield scale squeeze design to achieve an extended squeeze lifetime. PMID:27426410

  12. C-104 Solid Phase Characterization of Sample 4C-13-1 From Tank 241-C-104 Closure Sampling Event

    SciTech Connect

    Cooke, Gary A.; Pestovich, John A.

    2013-06-12

    One solid grab sample from closure sampling in Riser 7 of tank 214-C-I04 (C-I04) was examined to determine the solid phases that were present. The sample was analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The purpose of this analysis was to see if the presence of hydrated phases could provide a possible explanation for the high moisture content obtained from thermogravimetric analysis (TGA).

  13. Mechanistic understanding of calcium-phosphonate solid dissolution and scale inhibitor return behavior in oilfield reservoir: formation of middle phase.

    PubMed

    Zhang, Ping; Shen, Dong; Ruan, Gedeng; Kan, Amy T; Tomson, Mason B

    2016-08-01

    Phosphonates are an important class of mineral scale inhibitors used for oilfield scale control. By injecting the phosphonate into an oilfield reservoir, calcium-phosphonate precipitate will form and subsequently release the phosphonate into produced water for scale control. In this study, a systematic procedure is developed to mechanistically characterize an acidic calcium-phosphonate amorphous material that is later developed into a middle phase and eventually a crystalline phase. The phosphonate used in this study is diethylenetriamine pentakis (methylene phosphonic acid) (DTPMP). An amorphous calcium-DTPMP solid is precipitated by mixing a calcium-containing solution with a DTPMP solution. The stoichiometry of this initially formed solid can be experimentally confirmed via a static dissolution test. Following another dynamic development test, two additional Ca-DTPMP solid phases, i.e., a middle phase and a crystalline phase have been observed. Electron microscopy and X-ray diffraction were employed to characterize the morphology and crystallinity of different Ca-DTPMP solids of interest. Evidently, the dynamic brine flushing of the Ca-DTPMP solid developed the initially amorphous material into a middle phase solid with an amorphous/microcrystalline structure and eventually into a crystalline material. Furthermore, a dissolution characterization study was carried out to determine the solubility product of the middle phase solid at different conditions. The obtained mechanistic understanding of the Ca-DTPMP solid related to precipitation chemistry, dissolution behavior and phase transition is critical to elucidate oilfield DTPMP return data and more importantly, can optimize the oilfield scale squeeze design to achieve an extended squeeze lifetime.

  14. Solid Phase Red Cell Adherence Assay: a tubeless method for pretransfusion testing and other applications in transfusion science.

    PubMed

    Ching, Eric

    2012-06-01

    Solid Phase Red Cell Adherence Assay (SPRCA) is one of the two tubeless methods developed to improve sensitivity and specificity in blood group serology. The SPRCA (solid phase) and the column agglutination (gel) technology have gained wide acceptance following successful adaptation to fully automated platforms, The purpose of this paper is to discuss the development, principle, procedures as well as laboratory and clinical applications of the SPRCA in transfusion medicine.

  15. Advanced Multi-phase Flow CFD Model Development for Solid Rocket Motor Flowfield Analysis

    NASA Technical Reports Server (NTRS)

    Liaw, Paul; Chen, Yen-Sen

    1995-01-01

    A Navier-Stokes code, finite difference Navier-Stokes (FDNS), is used to analyze the complicated internal flowfield of the SRM (solid rocket motor) to explore the impacts due to the effects of chemical reaction, particle dynamics, and slag accumulation on the solid rocket motor (SRM). The particulate multi-phase flowfield with chemical reaction, particle evaporation, combustion, breakup, and agglomeration models are included in present study to obtain a better understanding of the SRM design. Finite rate chemistry model is applied to simulate the chemical reaction effects. Hermsen correlation model is used for the combustion simulation. The evaporation model introduced by Spalding is utilized to include the heat transfer from the particulate phase to the gase phase due to the evaporation of the particles. A correlation of the minimum particle size for breakup expressed in terms of the Al/Al2O3 surface tension and shear force was employed to simulate the breakup of particles. It is assumed that the breakup occurs when the Weber number exceeds 6. A simple L agglomeration model is used to investigate the particle agglomeration. However, due to the large computer memory requirements for the agglomeration model, only 2D cases are tested with the agglomeration model. The VOF (Volume of Fluid) method is employed to simulate the slag buildup in the aft-end cavity of the redesigned solid rocket motor (RSRM). Monte Carlo method is employed to calculate the turbulent dispersion effect of the particles. The flowfield analysis obtained using the FDNS code in the present research with finite rate chemical reaction, particle evaporation, combustion, breakup, agglomeration, and VOG models will provide a design guide for the potential improvement of the SRM including the use of materials and the shape of nozzle geometry such that a better performance of the SRM can be achieved. The simulation of the slag buildup in the aft-end cavity can assist the designer to improve the design of

  16. Advanced multi-phase flow CFD model development for solid rocket motor flowfield analysis

    NASA Astrophysics Data System (ADS)

    Liaw, Paul; Chen, Yen-Sen

    1995-03-01

    A Navier-Stokes code, finite difference Navier-Stokes (FDNS), is used to analyze the complicated internal flowfield of the SRM (solid rocket motor) to explore the impacts due to the effects of chemical reaction, particle dynamics, and slag accumulation on the solid rocket motor (SRM). The particulate multi-phase flowfield with chemical reaction, particle evaporation, combustion, breakup, and agglomeration models are included in present study to obtain a better understanding of the SRM design. Finite rate chemistry model is applied to simulate the chemical reaction effects. Hermsen correlation model is used for the combustion simulation. The evaporation model introduced by Spalding is utilized to include the heat transfer from the particulate phase to the gase phase due to the evaporation of the particles. A correlation of the minimum particle size for breakup expressed in terms of the Al/Al2O3 surface tension and shear force was employed to simulate the breakup of particles. It is assumed that the breakup occurs when the Weber number exceeds 6. A simple L agglomeration model is used to investigate the particle agglomeration. However, due to the large computer memory requirements for the agglomeration model, only 2D cases are tested with the agglomeration model. The VOF (Volume of Fluid) method is employed to simulate the slag buildup in the aft-end cavity of the redesigned solid rocket motor (RSRM). Monte Carlo method is employed to calculate the turbulent dispersion effect of the particles. The flowfield analysis obtained using the FDNS code in the present research with finite rate chemical reaction, particle evaporation, combustion, breakup, agglomeration, and VOG models will provide a design guide for the potential improvement of the SRM including the use of materials and the shape of nozzle geometry such that a better performance of the SRM can be achieved. The simulation of the slag buildup in the aft-end cavity can assist the designer to improve the design of

  17. Solid{endash}fluid phase equilibrium for single component and binary Lennard-Jones systems: A cell theory approach

    SciTech Connect

    Cottin, X.; Monson, P.A.

    1996-12-01

    We consider the application of the cell theory to single component and binary Lennard-Jones solids. We calculate solid phase properties and solid{endash}fluid equilibrium using the cell theory for the solid phase and an equation of state for the fluid phase. In the single component case the thermodynamic properties as well as the solid{endash}fluid phase diagram predicted by the theory are in quite good agreement with Monte Carlo simulation results. The introduction of correlations between the motions of nearest neighbor particles into the cell theory in a fashion suggested by Barker significantly improves the agreement. For binary Lennard-Jones 12-6 mixtures the predictions of the theory are compared with experimental data for mixtures forming substitutionally disordered solid solutions involving argon, krypton and methane. The theory correctly predicts the form of the phase diagram but the quantitative predictions are quite sensitive to the choice of potential parameters. The shape of the phase diagram is similar to that for a hard sphere mixture with the same diameter ratio. {copyright} {ital 1996 American Institute of Physics.}

  18. The EPOS Implementation Phase: building thematic and integrated services for solid Earth sciences

    NASA Astrophysics Data System (ADS)

    Cocco, Massimo; Epos Consortium, the

    2015-04-01

    The European Plate Observing System (EPOS) has a scientific vision and approach aimed at creating a pan-European infrastructure for Earth sciences to support a safe and sustainable society. To follow this vision, the EPOS mission is integrating a suite of diverse and advanced Research Infrastructures (RIs) in Europe relying on new e-science opportunities to monitor and understand the dynamic and complex Earth system. To this goal, the EPOS Preparatory Phase has designed a long-term plan to facilitate integrated use of data and products as well as access to facilities from mainly distributed existing and new research infrastructures for solid Earth Science. EPOS will enable innovative multidisciplinary research for a better understanding of the Earth's physical processes that control earthquakes, volcanic eruptions, ground instability and tsunami as well as the processes driving tectonics and Earth surface dynamics. Through integration of data, models and facilities EPOS will allow the Earth Science community to make a step change in developing new concepts and tools for key answers to scientific and socio-economic questions concerning geo-hazards and geo-resources as well as Earth sciences applications to the environment and to human welfare. Since its conception EPOS has been built as "a single, Pan-European, sustainable and distributed infrastructure". EPOS is, indeed, the sole infrastructure for solid Earth Science in ESFRI and its pan-European dimension is demonstrated by the participation of 23 countries in its preparatory phase. EPOS is presently moving into its implementation phase further extending its pan-European dimension. The EPOS Implementation Phase project (EPOS IP) builds on the achievements of the successful EPOS preparatory phase project. The EPOS IP objectives are synergetic and coherent with the establishment of the new legal subject (the EPOS-ERIC in Italy). EPOS coordinates the existing and new solid Earth RIs within Europe and builds the

  19. Solid-phase synthesis and hybridization properties of DNA containing sulfide-linked dinucleosides.

    PubMed Central

    Kawai, S H; Wang, D; Giannaris, P A; Damha, M J; Just, G

    1993-01-01

    Oligodeoxyribonucleotides incorporating non-hydrolyzable dialkyl sulfide linked thymidine dimers (TsT) were synthesized chemically by the solid-phase approach. The sulfide dimer TsT was stable to degradation by snake-venom phosphodiesterase, calf spleen phosphodiesterase, Nuclease P1 and Nuclease S1. Thermal denaturation analysis indicated that the incorporation of TsT dimers into DNA weakened, but did not prevent, binding to complementary DNA and RNA over a wide range of salt concentrations (10 mM to 2 M NaCl). Images PMID:8464740

  20. A novel Fmoc-based anchorage for the synthesis of protected peptides on solid phase.

    PubMed

    Liu, Y Z; Ding, S H; Chu, J Y; Felix, A M

    1990-02-01

    A novel bifunctional compound, 9-(hydroxymethyl)-2-fluoreneacetic acid, was synthesized, coupled to benzhydrylamine-resin, and evaluated for its application to the solid phase synthesis of protected peptide fragments. Anchor-bond cleavage was achieved with 15% piperidine/DMF. A protected heptapeptide, Boc-Val-Val-Ser(Bzl)-His(Tos)-Phe-Asn-Lys-(Z)-OH, corresponding to the sequence (1-7) of rat-transforming growth factor-alpha, was synthesized using this new support with an overall yield of 46%.

  1. Click Reaction on Solid Phase Enables High Fidelity Synthesis of Nucleobase-Modified DNA.

    PubMed

    Tolle, Fabian; Rosenthal, Malte; Pfeiffer, Franziska; Mayer, Günter

    2016-03-16

    The post-synthetic functionalization of nucleic acids via click chemistry (CuAAC) has seen tremendous implementation, extending the applicability of nucleobase-modified nucleic acids in fields like fluorescent labeling, nanotechnology, and in vitro selection. However, the production of large quantities of high-density functionalized material via solid phase synthesis has been hampered by oxidative by-product formation associated with the alkaline workup conditions. Herein, we describe a rapid and cost-effective protocol for the high fidelity large-scale production of nucleobase-modified nucleic acids, exemplified with a recently described nucleobase-modified aptamer.

  2. Sequential, solid-phase assay for biotin in physiologic fluids that correlates with expected biotin status

    SciTech Connect

    Mock, D.M.; DuBois, D.B.

    1986-03-01

    Interest in accurate measurement of biotin concentrations in plasma and urine has been stimulated by recent advances in the understanding of biotin-responsive inborn errors of metabolism and by several reports describing acquired biotin deficiency during parenteral alimentation. This paper presents a biotin assay utilizing radiolabeled avidin in a sequential, solid-phase method; the assay has increased sensitivity compared to previous methods (greater than or equal to 10 fmol/tube), correlates with expected trends in biotin concentrations in blood and urine in a rat model of biotin deficiency, and can utilize commercially available radiolabeled avidin.

  3. Structurally Diverse Polyamines: Solid-Phase Synthesis and Interaction with DNA.

    PubMed

    Umezawa, Naoki; Horai, Yuhei; Imamura, Yuki; Kawakubo, Makoto; Nakahira, Mariko; Kato, Nobuki; Muramatsu, Akira; Yoshikawa, Yuko; Yoshikawa, Kenichi; Higuchi, Tsunehiko

    2015-08-17

    A versatile solid-phase approach based on peptide chemistry was used to construct four classes of structurally diverse polyamines with modified backbones: linear, partially constrained, branched, and cyclic. Their effects on DNA duplex stability and structure were examined. The polyamines showed distinct activities, thus highlighting the importance of polyamine backbone structure. Interestingly, the rank order of polyamine ability for DNA compaction was different to that for their effects on circular dichroism and melting temperature, thus indicating that these polyamines have distinct effects on secondary and higher-order structures of DNA.

  4. Volatiles from Michelia champaca flower: comparative analysis by simultaneous distillation-extraction and solid phase microextraction.

    PubMed

    Báez, Disnelys; Morales, Diego; Pino, Jorge A

    2012-05-01

    The chemical composition of the volatile compounds isolated by simultaneous distillation-extraction (SDE) and headspace-solid phase microextraction (SPME) from flowers of Michelia champaca growing in Cuba was investigated by GC/FID and GC/MS. Sixty-seven and thirty-four components were identified by SDE and SPME, respectively, with 1,8-cineole (22.8%) as the main constituent in the volatile oil isolated by SDE, and methyl benzoate (30.3%), indole (16.6%) and beta-elemene (10.4%) the major components detected by SPME.

  5. Synthesis of graphene nanoribbons from amyloid templates by gallium vapor-assisted solid-phase graphitization

    SciTech Connect

    Murakami, Katsuhisa Dong, Tianchen; Kajiwara, Yuya; Takahashi, Teppei; Fujita, Jun-ichi; Hiyama, Takaki; Takai, Eisuke; Ohashi, Gai; Shiraki, Kentaro

    2014-06-16

    Single- and double-layer graphene nanoribbons (GNRs) with widths of around 10 nm were synthesized directly onto an insulating substrate by solid-phase graphitization using a gallium vapor catalyst and carbon templates made of amyloid fibrils. Subsequent investigation revealed that the crystallinity, conductivity, and carrier mobility were all improved by increasing the temperature of synthesis. The carrier mobility of the GNR synthesized at 1050 °C was 0.83 cm{sup 2}/V s, which is lower than that of mechanically exfoliated graphene. This is considered to be most likely due to electron scattering by the defects and edges of the GNRs.

  6. A solid-phase radioimmunoassay for the determination of fibronectin levels in plasma

    SciTech Connect

    Pearlstein, E.; Baez, L.

    1981-09-15

    Fibronectin, iodinated in the absence of urea using lactoperoxidase coupled to Sepharose 4B, retained antigenic and biological activity. Utilizing the labeled protein, a solid-phase radioimmunoassay for the determination of the fibronectin concentraction in plasma was developed. The radioimmunoassay is rapid, uses small amounts of antibody, and obviates the need for a second antibody. It also facilitates the handling of large sample numbers.The mean plasma fibronectin level in normal individuals was 557 +/- 102 ..mu..g/ml, approximately 70% higher than values obtained by other procedures.

  7. Solid Phase Characterization of Tank 241-AY-102 Annulus Space Particulate

    SciTech Connect

    Cooke, G. A.

    2013-01-30

    The Special Analytical Studies Group at the 222-S Laboratory (222-S) examined the particulate recovered from a series of samples from the annular space of tank 241-AY-102 (AY-102) using solid phase characterization (SPC) methods. These include scanning electron microscopy (SEM) using the ASPEX®1 scanning electron microscope, X-ray diffraction (XRD) using the Rigaku®2 MiniFlex X-ray diffractometer, and polarized light microscopy (PLM) using the Nikon®3 Eclipse Pol optical microscope. The SEM is equipped with an energy dispersive X-ray spectrometer (EDS) to provide chemical information.

  8. Phase and strain distributions associated with reactive contaminants inside a solid oxide fuel cell.

    SciTech Connect

    Liu, D. J.; Almer, J.

    2009-01-01

    A microfocused synchrotron x-ray diffraction method was used to reveal the quantitative distributions of phase fractions, internal strains, and their interdependences at different layer depths inside of a planar solid oxide fuel cell, which was deactivated by chromium contamination through direct contact with the metallic interconnect under typical operating conditions. These observations provide insight into the mechanism of Cr poisoning. The method can serve as a versatile tool for studying the electrochemical devices with thin-layered construction such as batteries and fuel cells under static or in situ conditions.

  9. Surface characterization of commercial fibers for solid-phase microextraction and related problems in their application.

    PubMed

    Haberhauer-Troyer, C; Crnoja, M; Rosenberg, E; Grasserbauer, M

    2000-02-01

    The surfaces of commercially available polydimethylsiloxane (PDMS) and Carboxen-PDMS fibers for solid-phase microextraction (SPME) were investigated by optical and electron microscopy. Damage to the coating as well as contamination of new fibers and a highly variable number of pores in Carboxen-PDMS coatings were observed. Together with the contamination of the fibers during their use with metallic particles originating from the SPME fiber holder they are possible explanations for the problems encountered in the analysis of organolead, organotin and organosulfur compounds, such as artifact formation and low repeatability. PMID:11220312

  10. Automated solid-phase extraction of herbicides from water for gas chromatographic-mass spectrometric analysis

    USGS Publications Warehouse

    Meyer, M.T.; Mills, M.S.; Thurman, E.M.

    1993-01-01

    An automated solid-phase extraction (SPE) method was developed for the pre-concentration of chloroacetanilide and triazine herbicides, and two triazine metabolites from 100-ml water samples. Breakthrough experiments for the C18 SPE cartridge show that the two triazine metabolites are not fully retained and that increasing flow-rate decreases their retention. Standard curve r2 values of 0.998-1.000 for each compound were consistently obtained and a quantitation level of 0.05 ??g/l was achieved for each compound tested. More than 10,000 surface and ground water samples have been analyzed by this method.

  11. Low-temperature solid-state phase transformations in 2H silicon carbide.

    NASA Technical Reports Server (NTRS)

    Powell, J. A.; Will, H. A.

    1972-01-01

    Study of the phase transformations taking place in 2H SiC single crystals at temperatures as low as 400 C. Some crystals transformed to a structure with one-dimensional disorder along the crystal c axis. Others transformed to a faulted cubic/6H structure. The transformation is time and temperature dependent, and is greatly enhanced by dislocations. The transformation takes place by means of a slip process perpendicular to the c axis. Cubic SiC crystals were observed to undergo a solid-state transformation above 1400 C.

  12. Low-temperature solid-state phase transformations in 2H silicon carbide

    NASA Technical Reports Server (NTRS)

    Will, H. A.; Powell, J. A.

    1972-01-01

    Single crystals of 2H SiC were observed to undergo phase transformations at temperatures as low as 400 C. Some 2H crystals transformed to a structure with one-dimensional disorder along the crystal c axis. Others transformed to a faulted cubic/6H structure. The transformation is time and temperature dependent and is greatly enhanced by dislocations. Observations indicate that the transformation takes place by means of a slip process perpendicular to the c axis. Cubic SiC crystals were observed to undergo a solid state transformation above 1400 C.

  13. Click Reaction on Solid Phase Enables High Fidelity Synthesis of Nucleobase-Modified DNA.

    PubMed

    Tolle, Fabian; Rosenthal, Malte; Pfeiffer, Franziska; Mayer, Günter

    2016-03-16

    The post-synthetic functionalization of nucleic acids via click chemistry (CuAAC) has seen tremendous implementation, extending the applicability of nucleobase-modified nucleic acids in fields like fluorescent labeling, nanotechnology, and in vitro selection. However, the production of large quantities of high-density functionalized material via solid phase synthesis has been hampered by oxidative by-product formation associated with the alkaline workup conditions. Herein, we describe a rapid and cost-effective protocol for the high fidelity large-scale production of nucleobase-modified nucleic acids, exemplified with a recently described nucleobase-modified aptamer. PMID:26850226

  14. Challenges of infrared reflective spectroscopy of solid-phase explosives and chemicals on surfaces

    SciTech Connect

    Phillips, Mark C.; Suter, Jonathan D.; Bernacki, Bruce E.; Johnson, Timothy J.

    2012-09-01

    Reliable active and passive hyperspectral imaging and detection of explosives and solid-phase chemical residue on surfaces remains a challenge and an active area of research and development. Both methods rely on reference libraries for material identification, but in many cases the reference spectra do not sufficiently resemble those instrumental signals scattered from real-world objects. We describe a physics-based model using the dispersive complex dielectric constant to explain what is often thought of as anomalous behavior of scattered or non-specular signatures encountered in active and passive sensing of explosives or chemicals on surfaces and show modeling and experimental results for RDX.

  15. A method for solid phase synthesis of phosphors under increased pressure; creation of remote phosphors

    NASA Astrophysics Data System (ADS)

    Galashov, E. N.; Yusuf, A. A.; Mandrik, E. M.

    2016-08-01

    A method for phosphors solid-phase synthesis under high pressure is proposed. Using the method, phosphors based on rare earth garnets were synthesized at a temperature considerably lower (1300 °C) than the temperature of the synthesis by conventional method (above 1650 °C). Using organic, inorganic ligaments and synthesized phosphors, remote phosphors were created. The chromaticity coordinates of created LEDs on the base of blue LEDs and remote phosphors fall into the bin of white and green colours. Luminous efficiency reaches 140 lm/W.

  16. Solid phase synthesis of functionalised SAM-forming alkanethiol-oligoethyleneglycols.

    PubMed

    Murray, James; Nowak, Dominika; Pukenas, Laurynas; Azhar, Rizuan; Guillorit, Mathieu; Wälti, Christoph; Critchley, Kevin; Johnson, Steven; Bon, Robin S

    2014-06-28

    We present an efficient solid phase synthesis methodology that provides easy access to a range of functionalised long-chain alkanethiol-oligoethyleneglycols that form well-defined self-assembled monolayers on gold and are compatible with pre- or post-assembly conjugation of (bio)molecules. We demonstrate the versatility of our synthetic route by synthesising LCAT-OEGs with a range of functional moieties, including peptides, electro-active redox groups, chemical handles for post-assembly conjugation of (bio)molecules, and demonstrate the application of our LCAT-OEG monolayers in immunosensing, where they show good biocompatibility with minimal biofouling. PMID:25400934

  17. Solid phase electron donors control denitrification in groundwater at agricultural sites

    NASA Astrophysics Data System (ADS)

    Green, C. T.; Liao, L.; Bekins, B. A.; Bohlke, J. K.

    2011-12-01

    Increased concentrations of nitrate in groundwater caused by agricultural use of chemical and organic fertilizers are a concern because of possible risks to environmental and human health. At many sites, these problems are mitigated by natural attenuation of nitrate as a result of microbially mediated denitrification of nitrate to nitrogen gas. Recent studies have clarified the factors affecting the rates and extents of denitrification in groundwater in agricultural areas. Intensive studies were conducted by the US Geological Survey to study agricultural chemicals in California, Nebraska, Washington, and Maryland using laboratory analyses, field measurements, and flow and transport modeling for monitoring well transects (0.5 to 2.5 km in length) and vertical profiles (0 to 50 m in depth). Groundwater analyses included major ion chemistry, dissolved gases, nitrogen and oxygen stable isotopes, and atmospheric age-tracers. Sediments were analyzed for concentrations of potential electron donors for denitrification, including reduced iron and sulfur, and organic carbon. Geochemical data and mass balance calculations indicated that solid-phase electron donors were an important factor controlling denitrification at these sites. To examine the generality of this result, a mathematical model of vertical flux of water, oxygen, and nitrate was developed and applied at these study sites along with 2 new study sites in Iowa and Mississippi and 8 additional sites from previous studies in Nebraska, Texas, Minnesota, Wisconsin, North Carolina, Maryland (2 sites), and New York. Model results confirmed the importance of solid phase electron donors. The normalized reaction rates on an electron flux basis tended to increase with depth from the shallow oxygen reduction zone to the underlying nitrate reduction zone. The pattern of higher rates at depth is consistent with a reaction rate controlled by solid phase donors that are depleted under oxidizing conditions near the surface and in

  18. Synthesis of graphene nanoribbons from amyloid templates by gallium vapor-assisted solid-phase graphitization

    NASA Astrophysics Data System (ADS)

    Murakami, Katsuhisa; Dong, Tianchen; Kajiwara, Yuya; Hiyama, Takaki; Takahashi, Teppei; Takai, Eisuke; Ohashi, Gai; Shiraki, Kentaro; Fujita, Jun-ichi

    2014-06-01

    Single- and double-layer graphene nanoribbons (GNRs) with widths of around 10 nm were synthesized directly onto an insulating substrate by solid-phase graphitization using a gallium vapor catalyst and carbon templates made of amyloid fibrils. Subsequent investigation revealed that the crystallinity, conductivity, and carrier mobility were all improved by increasing the temperature of synthesis. The carrier mobility of the GNR synthesized at 1050 °C was 0.83 cm2/V s, which is lower than that of mechanically exfoliated graphene. This is considered to be most likely due to electron scattering by the defects and edges of the GNRs.

  19. Novel nanoporous sorbent for solid-phase extraction in petroleum fingerprinting

    NASA Astrophysics Data System (ADS)

    Alayande, S. Oluwagbemiga; Hlengilizwe, Nyoni; Dare, E. Olugbenga; Msagati, Titus A. M.; Akinlabi, A. Kehinde; Aiyedun, P. O.

    2016-04-01

    Sample preparation is crucial in the analysis of petroleum and its derivatives. In this study, developing affordable sorbent for petroleum fingerprinting analysis using polymer waste such expanded polystyrene was explored. The potential of electrospun expanded polystyrene (EPS) as a sorbent for the solid-phase extraction (SPE) technique was investigated, and its efficiency was compared with commercial cartridges such as alumina, silica and alumina/silica hybrid commercial for petroleum fingerprinting analysis. The chromatograms showed that the packed electrospun EPS fibre demonstrated excellent properties for SPE applications relative to the hybrid cartridges.

  20. Polycrystalline silicon thin-film solar cell prepared by the solid phase crystallization (SPC) method

    SciTech Connect

    Baba, T.; Matsuyama, T.; Sawada, T.; Takahama, T.; Wakisaka, K.; Tsuda, S.; Nakano, S.

    1994-12-31

    A solid phase crystallization (SPC) method was applied to the fabrication of thin-film polycrystalline silicon (poly-Si) for solar cells for the first time. Among crystalline silicon solar cells crystallized at a low temperature of less than 600 C, the world`s highest conversion efficiency of 8.5% was achieved in a solar cell using thin-film poly-Si with only 10 {micro}m thickness prepared by the SPC method. This solar cell showed high photosensitivity in the long-wavelength region of more than 800 nm and also exhibited no light-induced degradation after light exposure.

  1. Perovskite solid solutions with multiferroic morphotropic phase boundaries and property enhancement

    NASA Astrophysics Data System (ADS)

    Algueró, M.; Amorín, H.; Fernández-Posada, C. M.; Peña, O.; Ramos, P.; Vila, E.; Castro, A.

    2016-05-01

    Recently, large phase-change magnetoelectric response has been anticipated by a first-principles investigation of phases in the BiFeO3-BiCoO3 perovskite binary system, associated with the existence of a discontinuous morphotropic phase boundary (MPB) between multiferroic polymorphs of rhombohedral and tetragonal symmetries. This might be a general property of multiferroic phase instabilities, and a novel promising approach for room temperature magnetoelectricity. We review here our current investigations on the identification and study of additional material systems, alternative to BiFeO3-BiCoO3 that has only been obtained by high pressure synthesis. Three systems, whose phase diagrams were, in principle, liable to show multiferroic MPBs have been addressed: the BiMnO3-PbTiO3 and BiFeO3-PbTiO3 binary systems, and the BiFeO3-BiMnO3-PbTiO3 ternary one. A comprehensive study of multiferroism across different solid solutions was carried out based on electrical and magnetic characterizations, complemented with mechanical and electromechanical measurements. An in-depth structural analysis was also accomplished when necessary.

  2. Manipulation and visualization of two-dimensional phase distribution of vibrational wave functions in solid parahydrogen crystal

    NASA Astrophysics Data System (ADS)

    Katsuki, Hiroyuki; Ohmori, Kenzo; Horie, Toru; Yanagi, Hisao; Ohmori, Kenji

    2015-09-01

    Solid parahydrogen, which is known to have an exceptionally long vibrational coherence lifetime as a molecular solid, offers an ideal testbed to perform coherent control experiments in the condensed phase. Here we demonstrate the spatial manipulation and visualization of the relative phase of vibrational wave functions in solid parahydrogen. Spatial distribution of vibrational excitation is generated by femtosecond impulsive Raman excitation. It is shown that the imprinted initial phase can be manipulated by wave-front modulation of the excitation laser pulses with a spatial light modulator. An interferometric measurement is used to convert the spatial phase distribution of the vibrational wave functions to the amplitude distribution. We have confirmed that the spatial profile of the scattered anti-Stokes pulse reveals the spatial phase distribution of the wave functions. The read-and-write scheme demonstrated in this experiment is applicable to a broad range of Raman memory systems accessible by Λ -type transitions.

  3. Role of the Surface in Solid-Solid Phase Transitions: Molecular Dynamics Study of the α-γ Transition in Fe

    NASA Astrophysics Data System (ADS)

    Wang, Binjun; Urbassek, Herbert M.

    2016-05-01

    Using classical molecular dynamics simulation, we study the role of surfaces on solid-solid phase transformations. We contrast the transformation behavior of a thin film (two free surfaces) with a bulk system and with a system containing only one free surface. We focus on bcc Fe and induce the transformation from the bcc to the fcc phase by applying biaxial strain. We find that the critical strain at which the material transforms is independent of whether the system has a free surface or not. However, the nucleation mechanism of the new phase and also the transformation speed are strongly influenced by the existence of surfaces. While bulk systems fail early (after phase transformation to a polycrystal) under the applied load, systems with a free surface show a considerably higher ductility.

  4. Problems of Solid-Phase Synthesis in Cylindrical Ampoules under Explosive Loading

    NASA Astrophysics Data System (ADS)

    Zelepugin, S. A.; Ivanova, O. V.; Yunoshev, A. S.; Zelepugin, A. S.

    2016-04-01

    The peculiarities of solid-phase synthesis are studied experimentally and numerically in the aluminum-fluoroplastic and aluminum-sulfur mixtures in cylindrical ampoules under explosive loading. The experimental results show that the use of a mixture capable of ultrafast exothermic reactions leads to the destruction of a cylindrical ampoule under explosive loading. When the transient shock wave is reflected from the bottom lid of the ampoule as a compression wave, there is a sharp increase in pressure in the lower part of the ampoule, which is accompanied by the increase in rate of the chemical reaction. The high rate of heat release during the chemical reaction in the lower part of the ampoule causes the formation of a gas phase, which leads to a further increase in pressure and destruction of the ampoule.

  5. High-throughput biopolymer desalting by solid-phase extraction prior to mass spectrometric analysis.

    PubMed

    Gilar, M; Belenky, A; Wang, B H

    2001-06-29

    In the last 10 years mass spectrometry (MS) has become an important method for analysis of peptides, proteins and DNA. It was recently utilized for accurate high-throughput protein identification, sequencing and DNA genotyping. The presence of non-volatile buffers compromises sensitivity and accuracy of MS biopolymer analysis; it is essential to remove sample contaminants prior to analysis. We have developed a fast and efficient method for desalting of DNA oligonucleotides and peptides using 96-well solid-phase extraction plates packed with 5 mg of Waters Oasis HLB sorbent (Waters, Milford, MA, USA). This reversed-phase sorbent retains the biopolymer analytes, while non-retained inorganic ions are washed out with pure deionized water. DNA oligonucleotides or peptides are eluted using a small amount (20-100 microl) of acetonitrile-water (70:30, v/v) solution. The SPE desalting performance meets the requirements for MS applications such as protein digest analysis and DNA genotyping. PMID:11461010

  6. Determination of metrafenone in vegetables by matrix solid-phase dispersion and HPLC-UV method.

    PubMed

    Li, Jianjun; Li, Yangyang; Xu, Dongliang; Zhang, Jingyu; Wang, Yuxi; Luo, Chao

    2017-01-01

    A simple method for determination of metrafenone in vegetables by matrix solid-phase dispersion (MSPD) and HPLC was developed. All vegetable samples were extracted with dichloromethane, and then the extracts were directly separated on a reversed-phase column with isocratic elution without a cleanup step. The linearity of metrafenone was good with the concentration between 0.005 and 5mg/kg, and the limit of detection (LOD) of the metrafenone was 0.002mg/kg. The recoveries ranged from 86.5% to 104.8% with the relative standard deviations (RSDs) in the range of 2.1-7.9% (n=6). The results indicated that the method was simple, rapid, highly sensitive and suitable for the determination of metrafenone in vegetables. PMID:27507450

  7. Determination of chloroacetic acids in drinking water using suppressed ion chromatography with solid-phase extraction.

    PubMed

    Yoshikawa, Kenji; Soda, Yuko; Sakuragawa, Akio

    2009-12-01

    Suppressed ion chromatography with a conductivity detector was developed for the determination of trace amounts of underivatized chloroacetic acids (CAAs). When sodium carbonate and methanol were used as a mobile phase, the simultaneous determination of each CAA took approximately 25 min. The linearity, reproducibility and detection limits were determined for the proposed method. For the solid-phase extraction step, the effects of the pH of the sample solution, sample volume and the eluting agent were tested. Under the optimized extracting conditions, the average recoveries for CAAs spiked in tap water were 83-107%, with an optimal preconcentration factor of 20. The reproducibility of recovery rate for CAAs was 1.2-3.8%, based upon 6 repetitions of the recovery experiments.

  8. On the interplay between chemical reactions and phase transitions for molecules adsorbed on solid surfaces

    NASA Astrophysics Data System (ADS)

    Stiles, M.; Metiu, H.

    1986-02-01

    There is a large body of experimental evidence suggesting that the rate of product formation in a reaction between adsorbed molecules is deeply modified when one of the reagents undergoes a phase transition or, more broadly speaking, an aggregation of some kind. Specific examples are: H2 and CO oxidation; methanol transformation into a methoxy radical on O/Cu; the water reaction with oxygen to form 2OH; the decomposition of N2O on Pt(111) which is affected by a phase transition in the outermost Pt layer; and the oxidation of Ni7. It is suspected that similar effects might operate on supported metal catalysts. We use Monte Carlo simulations to examine the manner in which reagent aggregation affects the reaction rate between molecules adsorbed on a solid surface. We discuss the temperature and concentration dependence of the rate of product formation.

  9. "Reagentless" flow injection determination of ammonia and urea using membrane separation and solid phase basification

    NASA Technical Reports Server (NTRS)

    Akse, J. R.; Thompson, J. O.; Sauer, R. L.; Atwater, J. E.

    1998-01-01

    Flow injection analysis instrumentation and methodology for the determination of ammonia and ammonium ions in an aqueous solution are described. Using in-line solid phase basification beds containing crystalline media. the speciation of ammoniacal nitrogen is shifted toward the un-ionized form. which diffuses in the gas phase across a hydrophobic microporous hollow fiber membrane into a pure-water-containing analytical stream. The two streams flow in a countercurrent configuration on opposite sides of the membrane. The neutral pH of the analytical stream promotes the formation of ammonium cations, which are detected using specific conductance. The methodology provides a lower limit of detection of 10 microgram/L and a dynamic concentration range spanning three orders of magnitude using a 315-microliters sample injection volume. Using immobilized urease to enzymatically promote the hydrolysis of urea to produce ammonia and carbon dioxide, the technique has been extended to the determination of urea.

  10. Temperature-responsive Solid-phase Extraction Column for Biological Sample Pretreatment.

    PubMed

    Akimaru, Michiko; Okubo, Kohei; Hiruta, Yuki; Kanazawa, Hideko

    2015-01-01

    We have developed a novel solid-phase extraction (SPE) system utilizing a temperature-responsive polymer hydrogel-modified stationary phase. Aminopropyl silica beads (average diameter, 40 - 64 μm) were coated with poly(N-isopropylacrylamide) (PNIPAAm)-based thermo-responsive hydrogels. Butyl methacrylate (BMA) and N,N-dimethylaminopropyl acrylamide (DMAPAAm) were used as the hydrophobic and cationic monomers, respectively, and copolymerized with NIPAAm. To evaluate the use of this SPE cartridge for the analysis of drugs and proteins in biological fluids, we studied the separation of phenytoin and theophylline from human serum albumin (HSA) as a model system. The retention of the analytes in an exclusively aqueous eluent could be modulated by changing the temperature and salt content. These results indicated that this temperature-responsive SPE system can be applied to the pretreatment of biological samples for the measurement of serum drug levels.

  11. Solid-liquid phase coexistence of alkali nitrates from molecular dynamics simulations.

    SciTech Connect

    Jayaraman, Saivenkataraman

    2010-03-01

    Alkali nitrate eutectic mixtures are finding application as industrial heat transfer fluids in concentrated solar power generation systems. An important property for such applications is the melting point, or phase coexistence temperature. We have computed melting points for lithium, sodium and potassium nitrate from molecular dynamics simulations using a recently developed method, which uses thermodynamic integration to compute the free energy difference between the solid and liquid phases. The computed melting point for NaNO3 was within 15K of its experimental value, while for LiNO3 and KNO3, the computed melting points were within 100K of the experimental values [4]. We are currently extending the approach to calculate melting temperatures for binary mixtures of lithium and sodium nitrate.

  12. CRYOCHEM, Thermodynamic Model for Cryogenic Chemical Systems: Solid-Vapor and Solid-Liquid-Vapor Phase Equilibria Toward Applications on Titan and Pluto

    NASA Astrophysics Data System (ADS)

    Tan, S. P.; Kargel, J. S.; Adidharma, H.; Marion, G. M.

    2014-12-01

    Until in-situ measurements can be made regularly on extraterrestrial bodies, thermodynamic models are the only tools to investigate the properties and behavior of chemical systems on those bodies. The resulting findings are often critical in describing physicochemical processes in the atmosphere, surface, and subsurface in planetary geochemistry and climate studies. The extremely cold conditions on Triton, Pluto and other Kuiper Belt Objects, and Titan introduce huge non-ideality that prevents conventional models from performing adequately. At such conditions, atmospheres as a whole—not components individually—are subject to phase equilibria with their equilibrium solid phases or liquid phases or both. A molecular-based thermodynamic model for cryogenic chemical systems, referred to as CRYOCHEM, the development of which is still in progress, was shown to reproduce the vertical composition profile of Titan's atmospheric methane measured by the Huygens probe (Tan et al., Icarus 2013, 222, 53). Recently, the model was also used to describe Titan's global circulation where the calculated composition of liquid in Ligeia Mare is consistent with the bathymetry and microwave absorption analysis of T91 Cassini fly-by data (Tan et al., 2014, submitted). Its capability to deal with equilibria involving solid phases has also been demonstrated (Tan et al., Fluid Phase Equilib. 2013, 360, 320). With all those previous works done, our attention is now shifting to the lower temperatures in Titan's tropopause and on Pluto's surface, where much technical development remains for CRYOCHEM to assure adequate performance at low temperatures. In these conditions, solid-vapor equilibrium (SVE) is the dominant phase behavior that determines the composition of the atmosphere and the existing ices. Another potential application is for the subsurface phase equilibrium, which also involves liquid, thus three-phase equilibrium: solid-liquid-vapor (SLV). This presentation will discuss the

  13. Advanced Multi-Phase Flow CFD Model Development for Solid Rocket Motor Flowfield Analysis

    NASA Technical Reports Server (NTRS)

    Liaw, Paul; Chen, Y. S.; Shang, H. M.; Doran, Denise

    1993-01-01

    It is known that the simulations of solid rocket motor internal flow field with AL-based propellants require complex multi-phase turbulent flow model. The objective of this study is to develop an advanced particulate multi-phase flow model which includes the effects of particle dynamics, chemical reaction and hot gas flow turbulence. The inclusion of particle agglomeration, particle/gas reaction and mass transfer, particle collision, coalescence and breakup mechanisms in modeling the particle dynamics will allow the proposed model to realistically simulate the flowfield inside a solid rocket motor. The Finite Difference Navier-Stokes numerical code FDNS is used to simulate the steady-state multi-phase particulate flow field for a 3-zone 2-D axisymmetric ASRM model and a 6-zone 3-D ASRM model at launch conditions. The 2-D model includes aft-end cavity and submerged nozzle. The 3-D model represents the whole ASRM geometry, including additional grain port area in the gas cavity and two inhibitors. FDNS is a pressure based finite difference Navier-Stokes flow solver with time-accurate adaptive second-order upwind schemes, standard and extended k-epsilon models with compressibility corrections, multi zone body-fitted formulations, and turbulence particle interaction model. Eulerian/Lagrangian multi-phase solution method is applied for multi-zone mesh. To simulate the chemical reaction, penalty function corrected efficient finite-rate chemistry integration method is used in FDNS. For the AL particle combustion rate, the Hermsen correlation is employed. To simulate the turbulent dispersion of particles, the Gaussian probability distribution with standard deviation equal to (2k/3)(exp 1/2) is used for the random turbulent velocity components. The computational results reveal that the flow field near the juncture of aft-end cavity and the submerged nozzle is very complex. The effects of the turbulent particles affect the flow field significantly and provide better

  14. Experimental and computational thermochemical study and solid-phase structure of 5,5-dimethylbarbituric acid.

    PubMed

    Roux, María Victoria; Notario, Rafael; Foces-Foces, Concepción; Temprado, Manuel; Ros, Francisco; Emel'yanenko, Vladimir N; Verevkin, Sergey P

    2010-03-18

    This paper reports an experimental and computational thermochemical study on 5,5-dimethylbarbituric acid and the solid-phase structure of the compound. The value of the standard (p(o) = 0.1 MPa) molar enthalpy of formation in the gas phase at T = 298.15 K has been determined. The energy of combustion was measured by static bomb combustion calorimetry, and from the result obtained, the standard molar enthalpy of formation in the crystalline state at T = 298.15 K was calculated as -(706.4 +/- 2.2) kJ x mol(-1). The enthalpy of sublimation was determined using a transference (transpiration) method in a saturated NB(2) stream, and a value of the enthalpy of sublimation at T = 298.15 K was derived as (115.8 +/- 0.5) kJ x mol(-1). From these results a value of -(590.6 +/- 2.3) kJ x mol(-1) for the gas-phase enthalpy of formation at T = 298.15 K was determined. Theoretical calculations at the G3 level were performed, and a study on molecular and electronic structure of the compound has been carried out. Calculated enthalpies of formation are in reasonable agreement with the experimental value. 5,5-Dimethylbarbituric acid was characterized by single crystal X-ray diffraction analysis. In the crystal structure, N-H...O=C hydrogen bonds lead to the formation of ribbons connected further by weak C-H...O=C hydrogen bonds into a three-dimensional network. The molecular and supramolecular structures observed in the solid state were also investigated in the gas phase by DFT calculations. PMID:20180529

  15. Experimental and computational thermochemical study and solid-phase structure of 5,5-dimethylbarbituric acid.

    PubMed

    Roux, María Victoria; Notario, Rafael; Foces-Foces, Concepción; Temprado, Manuel; Ros, Francisco; Emel'yanenko, Vladimir N; Verevkin, Sergey P

    2010-03-18

    This paper reports an experimental and computational thermochemical study on 5,5-dimethylbarbituric acid and the solid-phase structure of the compound. The value of the standard (p(o) = 0.1 MPa) molar enthalpy of formation in the gas phase at T = 298.15 K has been determined. The energy of combustion was measured by static bomb combustion calorimetry, and from the result obtained, the standard molar enthalpy of formation in the crystalline state at T = 298.15 K was calculated as -(706.4 +/- 2.2) kJ x mol(-1). The enthalpy of sublimation was determined using a transference (transpiration) method in a saturated NB(2) stream, and a value of the enthalpy of sublimation at T = 298.15 K was derived as (115.8 +/- 0.5) kJ x mol(-1). From these results a value of -(590.6 +/- 2.3) kJ x mol(-1) for the gas-phase enthalpy of formation at T = 298.15 K was determined. Theoretical calculations at the G3 level were performed, and a study on molecular and electronic structure of the compound has been carried out. Calculated enthalpies of formation are in reasonable agreement with the experimental value. 5,5-Dimethylbarbituric acid was characterized by single crystal X-ray diffraction analysis. In the crystal structure, N-H...O=C hydrogen bonds lead to the formation of ribbons connected further by weak C-H...O=C hydrogen bonds into a three-dimensional network. The molecular and supramolecular structures observed in the solid state were also investigated in the gas phase by DFT calculations.

  16. Extension of Toth function from gas-solid to liquid-solid equilibria and application to reversed-phase liquid chromatography systems

    SciTech Connect

    Gritti, Fabrice; Guiochon, Georges A

    2006-03-01

    The extension of the {Psi} function developed by Toth from equilibria taking place at gas-solid interfaces to those taking place at liquid-solid interfaces was investigated. The results were applied to conventional liquid-solid systems used in reversed-phase liquid chromatography (RPLC). The adsorbents in these systems are made of porous silica having a hydrophobic solid surface obtained by chemically bonding C{sub 18} alkyl chains to a porous silica gel then endcapping the surface with trimethylsilyl groups. The liquid is an aqueous solution of an organic solvent, most often methanol or acetonitrile. The probe compound used here is phenol. Adsorption data of phenol were measured using the dynamic frontal analysis (FA) method. The excess adsorption of the organic solvent was measured using the minor disturbance (MD) method. Activity coefficients in the bulk were estimated through the UNIFAC group contributions. The results show that the {Psi} function predicts 90% of the total free energy of immersion, {Delta}F, of the solid when the concentration of phenol is moderate (typically less than 10 g/L). At higher concentrations, the nonideal behavior of the bulk liquid phase becomes significant and it may contribute up to about 30% of {Delta}F. The high concentration of adsorbed molecules of phenol at the interface decreases the interfacial tension, {sigma}, by about 18 mN/m, independently of the structure of the adsorbed phase and of the nature of the organic solvent.

  17. Biogas production with horse dung in solid-phase digestion systems.

    PubMed

    Kusch, Sigrid; Oechsner, Hans; Jungbluth, Thomas

    2008-03-01

    Experiments on methanogenesis from horse dung were conducted in laboratory-scale batch reactors in order to determine the substrate performance in a solid-phase digestion process, more specifically in terms of potential energy recovery and suitable process technology. Dung from a horse stable with straw bedding was used. The temperature was kept in the mesophilic range. In the percolation process (with process water sprinkled over the stacked biomass) a proportion of 10-20% of solid inoculum (pre-digested horse dung) was found to be suitable. Comparative experiments with both percolation and flooding revealed a higher biogas production per volume for the flooded process, as no addition of solid inoculum was necessary. Methane yield from fresh material was similar in both processes: around 170 L(N) CH(4) per kg VS added was obtained in six-week cycles with untreated material under optimized conditions. Methane production was increased after chopping the substrate. Pre-aeration resulted in decreased methane production.

  18. Superfluid--Solid Quantum Phase Transitions and Landau-Ginzburg-Wilson Paradigm

    NASA Astrophysics Data System (ADS)

    Kuklov, A. B.; Prokof'ev, N. V.

    2005-03-01

    We study superfluid (SF)--solid zero-temperature transitions in 2d lattice boson/spin models by Worm-Algorithm Monte Carlo simulations. The SF -- Valence Bond Solid (VBS) transition was recently argued to be generically of II order in violation of the Ginzburg-Landau- Wilson (GLW) paradigm [1]. We simulate the J-current model on lattices up to 64x64x64, and observe that SF- columnar VBS and SF-checkerboard solid transitions are typically weak I-order ones and in small systems they may be confused with the continuous or high-symmetry points [2]. Thus, in the simulated model, the SF-VBS transition proceeds in agreement with the GLW paradigm. We explain this by dominance of standard particle and hole excitations, as opposed to fractionalized (spinon) excitations [1]. We developed a technique based on tunneling events (instantons) in the insulating phase which reveals charges of the revelant long-wave modes. While in 1d systems spinons are clearly seen in tunneling events, in two spatial dimensions tunneling is solely controlled by particles and holes in our system. This work is supported by NSF grant ITR-405460001 and PSC-CUNY- 665560035. [1] T. Senthil, A. Vishwanath, L. Balents, S. Sachdev, and M.P.A. Fisher, Science 303, 1490 (2004); [2] A.B. Kuklov, N.V. Prokof'ev, B.V. Svistunov, condmat/0406061; PRL, to be published.

  19. Continuous affinity-gradient nano-stationary phase served as a column for reversed-phase electrochromatography and matrix carrier in time-of-flight mass spectrometry for protein analysis.

    PubMed

    Wu, Jen-Kuei; Yang, Chung-Shi; Wu, Yi-Shiuan; Wang, Pen-Cheng; Tseng, Fan-Gang

    2015-08-19

    This study developed an affinity-gradient nano-stationary phase (AG-NSP) for protein analysis using nanofluidic capillary electrochromatography (nano-CEC) conjugated with matrix assisted laser desorption ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS). The AG-NSP can be used for protein pre-separation in nano-CEC and as a matrix carrier for protein analysis in MALDI-TOF-MS. A hydrophobicity gradient in AG-NSP was photochemically formed by grafting 4-azidoaniline hydrochloride on vertically arrayed multi-wall carbon nanotubes (MWCNTs) through gray-level exposure to UV light. The reversed-phase gradient stationary phase in AG-NSP was tailored according to the properties of the mobile phase gradient in capillary electrochromatography. As a result, the operation of the system is easily automated using a single buffer solution without the need for multiple solvents for elution. The use of nano-CEC with AG-NSP demonstrated excellent separation efficiency and high resolution for various types of DNA/protein/peptide. MALDI-TOF-MS analysis was then performed directly on the separated proteins and peptides on the chip. The proposed system was then used for the detection of three types of proteins with different molecular weights and PI values, including Cytochrome c (12,360, pI = 10), Lysozyme (14,300, pI = 11), and BSA (86,000, pI = 5)), and digested IgG fragments. The proposed system provided resolution of 1000 Da for the proteins in this study and the separation of digested IgG fragments at a low concentration of 1.2 pmol μL(-1).

  20. Molecularly imprinted solid-phase extraction for selective trace analysis of trifluoperazine.

    PubMed

    Attaran, Abdol Mohammad; Mohammadi, Narges; Javanbakht, Mehran; Akbari-Adergani, Behrouz

    2014-08-01

    In this study, a novel sample clean-up technique based on the molecularly imprinted solid-phase extraction procedure is described for the determination of trifluoperazine (TFP) in biological fluids. The water-compatible molecularly imprinted polymers (MIPs) were prepared by using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker, chloroform as porogen and TFP as the template molecule. The novel imprinted polymer was used as a solid-phase extraction sorbent for the extraction of TFP from human serum and urine samples. Various parameters affecting the extraction efficiency of the polymer were evaluated. The selectivity of MIPs was evaluated by checking several substances with molecular structures similar to the template. The limits of detection and quantification for TFP in urine samples were 0.06 and 0.2 µg/L, respectively. These limits for TFP in serum samples were 0.15 and 0.4 µg/L, respectively. The recovery values for serum and urine samples were higher than 92 and 93%, respectively.

  1. Improvement of multilayer graphene crystallinity by solid-phase precipitation with current stress application during annealing

    NASA Astrophysics Data System (ADS)

    Sahab Uddin, Md.; Ichikawa, Hiroyasu; Sano, Shota; Ueno, Kazuyoshi

    2016-06-01

    To improve the crystallinity of multilayer graphene (MLG) films by solid-phase precipitation, a new method by which current stress is introduced during annealing of a carbon-doped cobalt (Co-C) layer using cobalt (Co) as the catalyst has been investigated. The effects of current stress on the formation and crystallinity of MLG films were investigated by comparing the characteristics of the films annealed at the same temperature with and without current by taking into account the temperature rise due to Joule heating. The characteristics obtained by Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) measurements revealed that the MLG films produced were crystalline in nature and their crystallinity increased with applied current stress at the same temperature. From SEM observations, beside Joule heating, enhancement of Co grain size by agglomeration induced by current stress may be the potential reason for the improvement of the crystallinity of MLG films. We have also improved the uniformity of MLG films by depositing an additional copper (Cu) capping layer over the Co-C layer. Current stress application can lead to low-temperature fabrication of MLG with higher crystallinity by solid-phase precipitation.

  2. Rapid solid-phase extraction and analysis of resveratrol and other polyphenols in red wine.

    PubMed

    Hashim, Shima N N S; Schwarz, Lachlan J; Boysen, Reinhard I; Yang, Yuanzhong; Danylec, Basil; Hearn, Milton T W

    2013-10-25

    Red wine has long been credited as a good source of health-beneficial antioxidants, including the bioactive polyphenols catechin, quercetin, and (E)-resveratrol. In this paper, we report the application of reusable molecularly imprinted polymers (MIPs) for the selective and robust solid-phase extraction (SPE) and rapid analysis of (E)-resveratrol (LOD=8.87×10(-3) mg/L, LOQ=2.94×10(-2) mg/L), along with a range of other polyphenols from an Australian Pinot noir red wine. Optimization of the molecularly imprinted solid-phase extraction (MISPE) protocol resulted in the significant enrichment of (E)-resveratrol and several structurally related polyphenols. These secondary metabolites were subsequently identified by RP-HPLC and μLC-ESI ion trap MS/MS methods. The developed MISPE protocol employed low volumes of environmentally benign solvents selected according to the Green Chemistry principles, and resulted in the recovery of 99% of the total (E)-resveratrol present. These results further demonstrate the potential of generic protocols for the analysis of target compound with health beneficial properties within the food and nutraceutical industries using tailor-made MIPs.

  3. Sample cleanup using solid-phase dispersive extraction for determination of vancomycin in serum.

    PubMed

    Sakamoto, Yasuhiro; Jinno, Yuki; Shinodzuka, Ikumi; Iwasaki, Yusuke; Ito, Rie; Saito, Koichi

    2014-01-01

    A cleanup method employing quick and simple solid-phase dispersive extraction (SPDE) was investigated for its potential use in the determination of vancomycin (VCM) in serum by liquid chromatography/mass-spectrometry (LC/MS). SPDE was observed to be more rapid than conventional cartridge-type solid-phase extraction (SPE). In addition, in the analysis of viscous samples such as serum containing many proteins, SPDE could satisfactorily remove proteins even if deproteinization was not performed beforehand. The limit of detection (S/N = 3) and the limit of quantification (S/N > 10) of VCM by LC/MS were 0.05 and 0.2 ng/mL, respectively. The average recoveries of VCM from pooled serum spiked at 2, 10, and 100 ng/mL were 90.0, 90.8, and 98.6%, respectively. The repeatabilities were 7.5, 6.8, and 2.8%, and the intermediate precision values were 8.5, 6.8, and 7.0%, respectively. This suggests that the developed analytical method combing SPDE is useful for the determination of VCM in serum.

  4. Magneto-optical spectroscopic studies of solid and solution-phase tetra-phenyl porphyrin

    NASA Astrophysics Data System (ADS)

    Wahlen-Strothman, Jacob; Pan, Zhen Wen; Lamarche, Cody; Manning, Lane; Rawat, Naveen; Tokumoto, Takahisa; McGill, Stephen; Furis, Madalina; Chu, Kelvin

    2012-02-01

    Tetraphenylporphyrin (TPP) is a heterocyclic model system for porphyrins found in heme proteins, cytochromes and photosynthetic cofactors. TPP can accommodate a metal ion in the center; D-shell ion porphyrin complexes with a crystalline solid phase are of interest for magnetic studies because of the possibility of macroscopic long-range magnetic order of the ion spins. We have investigated the 5K magnetic properties of poly-crystalline thin films of TPP complexed with Zn, Mn and Cu and deposited through a room temperature capillary pen technique that produces grain size in the 100 micron to 1mm range. Our novel setup measures the UV/VIS, linear dichroism and MCD simultaneously and incorporates a photoelastic modulator and a microscopy superconducting magnet for high-field (5T) measurements. In addition, we present 25T data on samples from the new split magnet at NHMFL. We present solution and crystalline data on metal-complexed TPP; data are analyzed in terms of A and B-type MCD using a perimeter model. We find good agreement with previous solution data, and novel crystalline phase spectra that are correlated to the long range ordering of the solid state.

  5. Palladium-coated stainless-steel wire as a solid-phase microextraction fiber.

    PubMed

    Sun, Min; Feng, Juanjuan; Bu, Yanan; Wang, Xiaojiao; Duan, Huimi; Luo, Chuannan

    2015-05-01

    A novel palladium solid-phase microextraction coating was fabricated on a stainless-steel wire by a simple in situ oxidation-reduction process. The palladium coating exhibited a rough microscaled surface and its thickness was about 2 μm. Preparation conditions (reaction time and concentration of palladium chloride and hydrochloric acid) were optimized in detail to achieve sufficient extraction efficiency. Extraction properties of the fiber were investigated by direct immersion solid-phase microextraction of several polycyclic aromatic hydrocarbons and phthalate esters in aqueous samples. The extracted analytes were transferred into a gas chromatography system by thermal desorption. The effect of extraction and desorption conditions on extraction efficiency were investigated. Under the optimum conditions, good linearity was obtained and correlation coefficients between 0.9908 and 0.9990 were obtained. Limits of detection were 0.05-0.10 μg/L for polycyclic aromatic hydrocarbons and 0.3 μg/L for phthalate esters. Their recoveries for real aqueous samples were in the range from 97.1 to 121% and from 89.1 to 108%, respectively. The intra- and interday tests were also investigated with three different addition levels, and satisfactory results were also obtained.

  6. Isolation and analysis of sugar nucleotides using solid phase extraction and fluorophore assisted carbohydrate electrophoresis

    PubMed Central

    Barnes, Jarrod; Tian, Liping; Loftis, Jacqueline; Hiznay, James; Comhair, Suzy; Lauer, Mark; Dweik, Raed

    2016-01-01

    The building blocks of simple and complex oligosaccharides, termed sugar nucleotides, are often overlooked for their role in metabolic diseases and may hold the key to the underlying disease pathogenesis. Multiple reasons may account for the lack of analysis and quantitation of these sugar nucleotides, including the difficulty in isolation and purification as well as the required expensive instrumentation such as a high performance liquid chromatography (HPLC), mass spectrometer, or capillary electrophoresis. We have established a simple yet effective way to purify and quantitate sugar nucleotides using solid phase extraction (SPE) chromatography combined with fluorophore assisted carbohydrate electrophoresis (FACE). The simplicity of use, combined with the ability to run multiple samples at one time, give this technique a distinct advantage over the established methods for isolation and analysis of sugar nucleotides from cell culture models. • Sugar nucleotides can be easily purified with solid phase extraction chromatography. • FACE can be used to analyze multiple nucleotide sugar extracts with a single run. • The proposed method is simple, affordable, and uses common everyday research labware. PMID:27222820

  7. Solid-Phase Formation Of Isovaline, A Non-Biological, Meteoritic Amino Acid

    NASA Astrophysics Data System (ADS)

    Hudson, Reggie L.; Lewis, A. S.; Moore, M. H.; Dworkin, J. P.; Glavin, D. P.

    2007-10-01

    Among the Murchison (CM) meteoritic amino acids, isovaline stands out as being non-biological (nonprotein) and having a high abundance. Approximately equal amounts of D- and L-isovaline have been reported in CM meteorites, but the molecule's structure appears to prohibit racemization in aqueous solutions. While it is possible that isovaline could be made by the oft-studied Strecker reaction, laboratory experiments have seldom been able to produce this molecule from realistic molecular precursors. Recently we have investigated the low-temperature solid-phase chemistry of isovaline with an eye toward the molecule's formation, its stability, and the interconversion of its D- and L-enantiomers. Ion-irradiated isovaline-containing ices were examined by IR spectroscopy and highly-sensitive LC/ToF-MS methods to assess both amino acid destruction and racemization. Samples were studied both in the presence and absence of water-ice, and the destruction of isovaline was measured as a function of radiation dose. In addition, we have continued our earlier work on solid-phase amino acid formation, extending it to cover isovaline. In this presentation we will report the results of these newer investigations. This work was supported by a grant to the Goddard Center for Astrobiology through the NASA Astrobiology Institute. AL was supported by an award from the Summer Undergraduate Internship in Astrobiology program.

  8. Headspace solid-phase microextraction for direct determination of volatile phenols in cider.

    PubMed

    Pizarro, Consuelo; Pérez-del-Notario, Nuria; González-Sáiz, José María

    2009-11-01

    A headspace solid-phase microextraction coupled to gas chromatography-tandem mass spectrometry (GC-MS/MS) method was optimised and validated for the determination of 4-ethylguaiacol, 4-ethylphenol, 4-vinylguaiacol and 4-vinylphenol, involved in the presence of Brett character, in ciders. The influence of different parameters on extraction efficiency (fibre coating, salt addition, exposure time, extraction temperature and sample volume/total volume ratio) was evaluated. Divinylbenzene/carboxen/PDMS was selected as extraction fibre and the other optimised parameters were as follows: 10 mL of cider, temperature 70 degrees C, extraction time 60 min and addition of 0.4 g/mL of NaCl. The proposed method showed satisfactory linearity. The detection limits obtained were 0.01 microg/L for 4-ethylguaiacol, 0.02 microg/L for 4-ethylphenol, 0.08 microg/L for 4-vinylguaiacol and 0.03 microg/L for 4-vinylphenol. These detection limits were lower than those obtained in previous studies on the determination of volatile phenols in other alcoholic beverages. Good recoveries of over 95% were observed for all compounds, and the repeatability obtained was considered acceptable, ranging between 4 and 10%. To demonstrate the feasibility of the procedure, the method was applied to the analysis of commercial ciders. To our knowledge, this is the first time that the headspace solid-phase microextraction procedure has been optimised to determine specifically the Brett character responsible compounds in cider. PMID:20029909

  9. Integrated microfluidic device for solid-phase extraction coupled to micellar electrokinetic chromatography separation.

    PubMed

    Ramsey, Jeremy D; Collins, Greg E

    2005-10-15

    An integrated microdevice was utilized for the autonomous coupling of solid-phase extraction (SPE) to micellar electrokinetic chromatography (MEKC). Porous plugs of polymethacrylate polymer approximately 200 microm in length) were fabricated by ultraviolet irradiation in microchannels. Microcolumns of hydrophobic beads packed against the polymethacrylate plugs were utilized for the quantitative extraction of rhodamine B, yielding preconcentration factors over 200 for a 90-s extraction. The calculated detection limit for this dye was 60 fM. A sample of coumarin dyes were concentrated by SPE, eluted in a nonaqueous solvent from a separate on-chip reservoir, and injected by a gated valve onto a separate column for MEKC analysis. Using the integrated device, a completely automated sequence of extraction, elution, injection, separation, and detection were performed in less than 5 min. Observed separation efficiencies were high, with plate heights below 2 microm. The analysis was at least 3 times faster than semiautomated, conventional, solid-phase extraction, while requiring no user intervention. The design, fabrication, and autonomous operation of the device is discussed.

  10. Determination of cyproheptadine in feeds using molecularly imprinted solid-phase extraction coupled with HPLC.

    PubMed

    Yang, Jianwen; Wang, Zongnan; Zhou, Tong; Song, Xuqin; Liu, Qingyong; Zhang, Yuman; He, Limin

    2015-05-15

    A novel method was developed for the determination of cyproheptadine in feeds using molecularly imprinted solid-phase extraction coupled with high-performance liquid chromatography. The polymers were prepared using cyproheptadine as a template molecule, methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linking agent, and dichloromethane as a solvent by bulk polymerization. Under the optimum solid-phase extraction conditions, the molecular imprinting cartridge can selectively extract and enrich cyproheptadine from a variety of feeds. Mean recoveries of cyproheptadine from four kinds of feeds spiked at 0.1, 1.0 and 10mgkg(-1) ranged from 85.5% to 96.2%, with intra-day and inter-day relative standard deviation less than 10%. The calibration curve of cyproheptadine was good linear relationship (r>0.9993) within the range of 0.1-50μgmL(-1). The limit of detection (LOD) and the limit of quantification (LOQ) were 0.04 and 0.1mgkg(-1), respectively.

  11. Isolation of genomic DNA using magnetic nanoparticles as a solid-phase support

    NASA Astrophysics Data System (ADS)

    Saiyed, Z. M.; Ramchand, C. N.; Telang, S. D.

    2008-05-01

    In recent years, techniques employing magnetizable solid-phase supports (MSPS) have found application in numerous biological fields. This magnetic separation procedure offers several advantages in terms of subjecting the analyte to very little mechanical stress compared to other methods. Secondly, these methods are non-laborious, cheap, and often highly scalable. The current paper details a genomic DNA isolation method optimized in our laboratory using magnetic nanoparticles as a solid-phase support. The quality and yields of the isolated DNA from all the samples using magnetic nanoparticles were higher or equivalent to the traditional DNA extraction procedures. Additionally, the magnetic method takes less than 15 min to extract polymerase chain reaction (PCR) ready genomic DNA as against several hours taken by traditional phenol-chloroform extraction protocols. Moreover, the isolated DNA was found to be compatible in PCR amplification and restriction endonuclease digestion. The developed procedure is quick, inexpensive, robust, and it does not require the use of organic solvents or sophisticated instruments, which makes it more amenable to automation and miniaturization.

  12. Comparison of Fluorescence Microscopy and Solid-Phase Cytometry Methods for Counting Bacteria in Water

    PubMed Central

    Lisle, John T.; Hamilton, Martin A.; Willse, Alan R.; McFeters, Gordon A.

    2004-01-01

    Total direct counts of bacterial abundance are central in assessing the biomass and bacteriological quality of water in ecological and industrial applications. Several factors have been identified that contribute to the variability in bacterial abundance counts when using fluorescent microscopy, the most significant of which is retaining an adequate number of cells per filter to ensure an acceptable level of statistical confidence in the resulting data. Previous studies that have assessed the components of total-direct-count methods that contribute to this variance have attempted to maintain a bacterial cell abundance value per filter of approximately 106 cells filter−1. In this study we have established the lower limit for the number of bacterial cells per filter at which the statistical reliability of the abundance estimate is no longer acceptable. Our results indicate that when the numbers of bacterial cells per filter were progressively reduced below 105, the microscopic methods increasingly overestimated the true bacterial abundance (range, 15.0 to 99.3%). The solid-phase cytometer only slightly overestimated the true bacterial abundances and was more consistent over the same range of bacterial abundances per filter (range, 8.9 to 12.5%). The solid-phase cytometer method for conducting total direct counts of bacteria was less biased and performed significantly better than any of the microscope methods. It was also found that microscopic count data from counting 5 fields on three separate filters were statistically equivalent to data from counting 20 fields on a single filter. PMID:15345419

  13. Solid-propellant rocket motor internal ballistic performance variation analysis, phase 2

    NASA Technical Reports Server (NTRS)

    Sforzini, R. H.; Foster, W. A., Jr.

    1976-01-01

    The Monte Carlo method was used to investigate thrust imbalance and its first time derivative throughtout the burning time of pairs of solid rocket motors firing in parallel. Results obtained compare favorably with Titan 3 C flight performance data. Statistical correlations of the thrust imbalance at various times with corresponding nominal trace slopes suggest several alternative methods of predicting thrust imbalance. The effect of circular-perforated grain deformation on internal ballistics is discussed, and a modified design analysis computer program which permits such an evaluation is presented. Comparisons with SRM firings indicate that grain deformation may account for a portion of the so-called scale factor on burning rate between large motors and strand burners or small ballistic test motors. Thermoelastic effects on burning rate are also investigated. Burning surface temperature is calculated by coupling the solid phase energy equation containing a strain rate term with a model of gas phase combustion zone using the Zeldovich-Novozhilov technique. Comparisons of solutions with and without the strain rate term indicate a small but possibly significant effect of the thermoelastic coupling.

  14. The effect of surfactant and solid phase concentration on drug aggregates in model aerosol propellent suspensions.

    PubMed

    Bower, C; Washington, C; Purewal, T S

    1996-04-01

    The effect of increasing solid phase concentration on the morphology and flocculation rate of model aerosol suspensions has been investigated. Suspensions of micronized salbutamol sulphate and lactose in trichlorotrifluoroethane (P113) were studied under conditions of increasing shear stress. By use of image analysis techniques, measurement of aggregate size, fractal dimension and rate of aggregation was performed. The effect of the surfactant sorbitan monooleate on morphology and flocculation rate was also studied. Increased solid phase concentration caused an increase in the rate of aggregation and average aggregate size at a given value of shear stress. Surfactant addition retarded the aggregation rate, and caused a shift from a diffusion-limited cluster aggregation to a reaction-limited cluster aggregation mechanism. The aggregate profiles showed a corresponding change from rugged and crenellated without surfactant, to increasingly smooth and Euclidian with increasing surfactant concentration. The morphological changes were characterized by a decrease in the average boundary fractal dimension which also correlated well with the corresponding reduction in aggregation rate.

  15. Applications of monolithic solid-phase extraction in chromatography-based clinical chemistry assays.

    PubMed

    Bunch, Dustin R; Wang, Sihe

    2013-04-01

    Complex matrices, for example urine, serum, plasma, and whole blood, which are common in clinical chemistry testing, contain many non-analyte compounds that can interfere with either detection or in-source ionization in chromatography-based assays. To overcome this problem, analytes are extracted by protein precipitation, solid-phase extraction (SPE), and liquid-liquid extraction. With correct chemistry and well controlled material SPE may furnish clean specimens with consistent performance. Traditionally, SPE has been performed with particle-based adsorbents, but monolithic SPE is attracting increasing interest of clinical laboratories. Monoliths, solid pieces of stationary phase, have bimodal structures consisting of macropores, which enable passage of solvent, and mesopores, in which analytes are separated. This structure results in low back-pressure with separation capabilities similar to those of particle-based adsorbents. Monoliths also enable increased sample throughput, reduced solvent use, varied support formats, and/or automation. However, many of these monoliths are not commercially available. In this review, application of monoliths to purification of samples from humans before chromatography-based assays will be critically reviewed.

  16. Introducing Freshmen Students to the Practice of Solid-Phase Synthesis

    NASA Astrophysics Data System (ADS)

    Taralp, Alpay; Hulusi Türkseven, Can; Özgür Çakmak, Atilla; Çengel, Ömer

    2002-01-01

    A one-semester laboratory project on solid-phase peptide chemistry was designed pedagogically to cater to freshman science students. The approach not only permitted multistep syntheses that would be considered impractical in solution, but also gave students insight into fundamental aspects of research at an early stage of development. Young scientists prepared Bz-Asn-Asn-Phe and Bz-Asn-Gln-Phe--peptides envisaged as potential competitive inhibitors of chymotrypsin. The synthesis, defined by an attachment-deprotection cycle, two elongation-deprotection cycles, and a benzoyl-capping protocol, was completed manually on Wang resin using Fmoc chemistry. Students quantified the yield of each condensation and deprotection reaction by measuring levels of dibenzylfulvene chromophore, a stoichiometrically afforded by-product. Benzoylation of the N-terminus was confirmed by employing a cadmium-ninhydrin reagent. The group also ascertained, through use of a chromogenic substrate, that chymotrypsin-catalyzed hydrolysis was impeded slightly when carried out in the presence of target peptides. Supplementary analyses supporting peptide purity and composition were given to students. Grading was based on laboratory participation, project proposals, reports, and a concluding slide-show presentation made to peers and colleagues. While the project was time-consuming overall, students acquired an impression of research work and an appreciation of the utility of solid-phase methods.

  17. [Solid phase microextraction (SPME) of sample preparation during of a complex biological matrix in biotransformation studies].

    PubMed

    Kroll, C; Borchert, H H

    1998-03-01

    Within the scope of the investigation of drug metabolism in keratinocytes solid phase microextraction (SPME) was investigated as a suitable method for sample preparation. The application of SPME is based on the fact, that a amount of analyte is absorbed by the polymer fiber at equilibrium, and the fiber is localized on a tip of a GC-syringe. The stable nitroxyl radical TEMPO (2,2,6,6-tetramthylpiperidine-1-oxyl) and its apolar metabolite 2,2,6,6-tetramethylpiperidine were analyzed by SPME and subsequent GC using thymol as internal standard. By means of the headspace-technique and an apolar fiber the recovery rate of TEMPO and the metabolite was nearly 100% and the precision was high. However, the results of the direct SPME were unsatisfactory. In comparison with conventional liquid/liquid extraction and solid phase extraction SPE the SPME proved the best results with regard to recovery rate and precision. Furthermore, the main advantages of SPME are the renunciation of organic solvents, the saving of time, the possibility to reuse the fiber about 100-150 times and the option for a complete automatisation of the extraction procedure. PMID:9547519

  18. Solid phase extraction and metabolic profiling of exudates from living copepods

    PubMed Central

    Heuschele, Jan; Nylund, Göran M.; Pohnert, Georg; Pavia, Henrik; Bjærke, Oda; Pender-Healy, Larisa A.; Tiselius, Peter; Kiørboe, Thomas

    2016-01-01

    Copepods are ubiquitous in aquatic habitats. They exude bioactive compounds that mediate mate finding or induce defensive traits in prey organisms. However, little is known about the chemical nature of the copepod exometabolome that contributes to the chemical landscape in pelagic habitats. Here we describe the development of a closed loop solid phase extraction setup that allows for extraction of exuded metabolites from live copepods. We captured exudates from male and female Temora longicornis and analyzed the content with high resolution LC-MS. Chemometric methods revealed 87 compounds that constitute a specific chemical pattern either qualitatively or quantitatively indicating copepod presence. The majority of the compounds were present in both female and male exudates, but nine compounds were mainly or exclusively present in female exudates and hence potential pheromone candidates. Copepodamide G, known to induce defensive responses in phytoplankton, was among the ten compounds of highest relative abundance in both male and female extracts. The presence of copepodamide G shows that the method can be used to capture and analyze chemical signals from living source organisms. We conclude that solid phase extraction in combination with metabolic profiling of exudates is a useful tool to develop our understanding of the chemical interplay between pelagic organisms. PMID:26788422

  19. Matrix compatible solid phase microextraction coating, a greener approach to sample preparation in vegetable matrices.

    PubMed

    Naccarato, Attilio; Pawliszyn, Janusz

    2016-09-01

    This work proposes the novel PDMS/DVB/PDMS fiber as a greener strategy for analysis by direct immersion solid phase microextraction (SPME) in vegetables. SPME is an established sample preparation approach that has not yet been adequately explored for food analysis in direct immersion mode due to the limitations of the available commercial coatings. The robustness and endurance of this new coating were investigated by direct immersion extractions in raw blended vegetables without any further sample preparation steps. The PDMS/DVB/PDMS coating exhibited superior features related to the capability of the external PDMS layer to protect the commercial coating, and showed improvements in terms of extraction capability and in the cleanability of the coating surface. In addition to having contributed to the recognition of the superior features of this new fiber concept before commercialization, the outcomes of this work serve to confirm advancements in the matrix compatibility of the PDMS-modified fiber, and open new prospects for the development of greener high-throughput analytical methods in food analysis using solid phase microextraction in the near future.

  20. An Economical Online Solid-Phase Extraction LC-MS/MS Method for Quantifying Methylprednisolone.

    PubMed

    Hu, Xingjiang; Zheng, Yunliang; Wu, Guolan; Liu, Jian; Chen, Junchun; Huang, Mingzhu; Zhou, Huili; Wu, Lihua; Shen-Tu, Jianzhong

    2015-07-01

    An economical, reproducible and automated online solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry method was developed to quantify methylprednisolone in human plasma. The method was validated in terms of selectivity, precision/accuracy, process efficiency, stability, cartridge reproducibility and carryover studies. Sample pretreatment was performed by protein precipitation and elimination using methanol followed by water dilution. Then, the mixture was passed onto the HySphere C8 EC-SE online solid-phase extraction cartridge followed by the separation of the analytes on an Agilent Eclipse XDB column. Electrospray ionization in positive ion mode and multiple reaction monitoring were used to monitor the ion transitions at m/z 375.4/160.8 for methylprednisolone, and m/z 361.2/147.0 for prednisolone. The calibration curve ranged from 5.25 to 525 ng/mL. Meanwhile both the intra-day and inter-day precision values (relative standard deviation) were within 4.45%. The method which turns out to be less laborious, faster and lower consumable cost per sample has already been successfully applied to a pharmacokinetic study in which the oral administration of 16 mg methylprednisolone was conducted in Chinese volunteers.