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1

Features of the reaction of heterocyclic analogs of chalcone with lanthanide shift reagents  

SciTech Connect

The PMR spectra of heterocyclic analogs of 2-hydroxychalcone containing thiazole, benzofuran, triazole, imidazole, benzodioxane, or pyridine rings in the presence of lanthanide shift reagents are studied. It is found that the most effective reagent for modifying the spectra of these compounds is Yb(fod)3. The broadening of the spectra of 2-hydroxy chalcones in the presence of lanthanide shift reagents is explained by the dynamic effects of complex formation. An example is given of the determination of the conformation of molecules of 2-hydroxychalcone by the simultaneous use of lanthanide shift reagents and the homonuclear Overhauser effect. 9 refs., 1 fig., 1 tab.

Turov, A.V.; Khilya, V.P. [Taras Shevchenko Kiev Univ. (Russian Federation)

1994-10-01

2

Use of lanthanide shift reagents with [sup 31]P FT-NMR spectroscopy to analyze concentrated lake-water samples  

SciTech Connect

Several lanthanide shift reagents (LSR) were synthesized from praseodymium, europium, dysprosium, and terbium using ethylenediaminetetraacetic acid, trans-1,2-diaminocyclohexane-N,N,N[prime],N[prime]-tetraacetic acid, and diethylenetriaminepentaacetic acid for the purpose of separating overlapping [sup 31]P FT-NMR spectral signals of dissolved organic phosphorus compounds present in concentrated lake-water samples. The extent of change in signal position and line width of several known phosphorus compounds dissolved in pure water was examined as a function of solution pH and the molar ratio of LSR to phosphorus. Praseodymium ethylenediaminetetraacetate (PrEDTA) was determined to be the most effective LSR. Concentrated lake-water samples mixed with PrEDTA were examined with [sup 31]P FT-NMR. The use of PrEDTA provided separation of overlapping signals, indicated that phosphorus compounds were becoming isolated from the solution environment during sample concentration, enhanced the sensitivity of certain signals by possibly acting as a T[sub 1] relaxation agent, and did not precipitate in the presence of a high concentration of humic and fulvic acids. 31 refs., 4 figs., 1 tab.

Nanny, M.A.; Minear, R.A. (Univ. of Illinois, Urbana, IL (United States))

1994-08-01

3

High-resolution NMR spectroscopy of tricyclic non-alternant systems containing seven-membered rings—II. 1H and 13C solvent and lanthanide-shift-reagent studies of 5-keto- and 5-hydroxy-substituted 5H-dibenzo[ a, d]cycloheptene  

NASA Astrophysics Data System (ADS)

220 MHz 1H NMR spectra of 5H-dibenzo[ a, d]cyclohepten-5-one (I) in carbon disulphide and in deuteriated chloroform solution and of 5H-dibenzo[ a, d]cyclohepten-5-ol (II) in deuteriated chloroform at temperatures 223-323 K have been analysed by the LAOCOON III program; at low concentrations, two peaks emerge for each of H(5) and O H in II. Concentration and temperature dependences of 1H shifts indicate intermolecular association in II and, together with changes in 13C shifts with addition of Eu(fod) 3, suggest a structural inversion in I. Shift-reagent 1H studies reveal contributions from two orientations of Eu to I in the Eu(fod) 3-I complex but of predominantly one in the corresponding complex with II. 1H? 1H ortho-coupling constants, spread more widely in I than II, are compared with values in related compounds.

Drake, J. A. G.; Jones, D. W.

4

Lanthanide-induced phosphorus-31 NMR downfield chemical shifts of lysophosphatidylcholines are sensitive to lysophospholipid critical micelle concentration.  

PubMed Central

Lysophosphatidylcholine (lysoPC) monomers or micelles in water give rise to a narrow, isotropic phosphorus-31 NMR signal (40.6 ppm; v1/2 1.7 Hz; 32.2 MHz). Upon addition of praseodymium ions, the phosphorus signals are shifted downfield. However, the downfield shifts for the longer-chain lysophosphatidylcholines, which exist in the aggregated state, are far greater than those for the shorter-chain homologues, which exist as monomers. At a Pr3+/lysoPC molar ratio of 0.5, the signals of C12lysoPC through C18lysoPC were shifted by 12.1 ppm, whereas the signals of C6lysoPC and C8lysoPC were shifted by only 2.26 ppm. This very pronounced difference in lanthanide-induced downfield shifts between micelles and monomers can be utilized to determine with accuracy lysoPC critical micelle concentrations (CMC) from downfield shift-vs.-concentration plots. The CMC values we determined were 57 mM for C8lysoPC, 5.7 mM for C10lysoPC, and 0.6 mM for C12lysoPC. The shift reagent phosphorus-31 nuclear magnetic resonance technique particularly lends itself to the measurement of CMC values in the millimolar and high micromolar range. The method can equally be used for measuring critical micelle concentrations of short-chain phosphatidylcholines. PMID:2015376

Kumar, V V; Baumann, W J

1991-01-01

5

Nature of chiral-induced equilibrium shifts in racemic labile lanthanide complexes  

SciTech Connect

An analysis of the chiral-induced equilibrium shift of racemic D{sub 3} tris-terdendate complexes of lanthanides with 2,6-pyridinedicarboxylate is presented in terms of the associated/dissociated models of Schipper. Results are presented which indicate that the so-called Pfeiffer effect in these lanthanide complexes is best described by the dissociated model, as was determined for similar labile transition-metal complexes. The nature of the chiral discriminatory interaction is shown to be largely electrostatic by measurements in mixed solvents of varying dielectric constant.

Wu, Shuguang; Hilmes, G.L.; Riehl, J.P. (Univ. of Missouri, St. Louis (USA))

1989-03-23

6

Comparative Study of Ion Interaction Reagents for the Separation of Lanthanides by Reversed-Phase High Performance Liquid Chromatography (RP-HPLC)  

Microsoft Academic Search

A study of two ion interaction reagents (IIRs) viz. n-octadecane sulphonate (C18-sulphonate) and eicosyl sulphate (C20-sulphate) was carried out for the separation of lanthanides by reversed-phase high performance liquid chromatography (RP–HPLC). The objective of the study was to identify a suitable IIR offering long term adsorption onto the RP column, thereby obviating the need to introduce the IIR in the

P. G. Jaison; Pranaw Kumar; Vijay M. Telmore; Suresh K. Aggarwal

2009-01-01

7

Suppression of sodium nuclear magnetic resonance double-quantum coherence by chemical shift and relaxation reagents  

NASA Astrophysics Data System (ADS)

An investigation into the signal suppression behavior of the paramagnetic shift and relaxation reagents, Dy(P3O10)27- and Gd(P3O10)27-, with regard to their use in the nuclear magnetic resonance spectroscopic study of sodium has been performed. Measurements of T1 and T2 relaxation time constants of sodium in normal saline, Krebs-Henseleit buffer, and human blood serum, as a function of concentration of these reagents showed that, although closely coupled in the saline and K-H buffer environments, in plasma T1 and T2 become decoupled, transverse relaxation dominating in comparison to longitudinal relaxation. Linewidth measurements further suggest that relaxation in the plasma milieu is controlled primarily by inherent T2 relaxation, rather than by field inhomogeneity or diffusion effects. Quantitative single-quantum (1Q) and double-quantum (2Q) intensity measurements, biexponential T2 relaxation measurements, and parametric studies of the preparation time of the 2Q pulse sequence, were obtained in suspensions of bovine serum albumin and human erythrocytes. The observed suppression of sodium 2Q coherence by paramagnetic shift and relaxation reagents was found to exhibit a complex behavior in albumin solutions, involving the biexponential T2 decay to be expected during the preparation time of the 2Q filter pulse sequence, as well as the optimum preparation time for production of the double-quantum coherence itself. The controlling factor for both of these effects is the biexponential amplitude function in the expression for the transverse magnetization observed following application of the 2Q pulse sequence. This in turn is determined entirely by the values for the slow and fast components of biexponential relaxation in sodium, which themselves depend upon the concentration of the macromolecular binding sites for quadrupolar interaction. A similar behavior has been observed in suspensions of human erythrocytes.

Hutchison, Robert B.; Huntley, James J. A.; Jin, Haoran; Shapiro, Joseph I.

1992-12-01

8

Peptide-lanthanide cation equilibria in aqueous phase. I. Bound shifts for L-carnosine-praseodymium complexes  

NASA Astrophysics Data System (ADS)

L-Carnosine complexes of Pr 3+ were characterized in aqueous solution by 1H NMR and potentiometric titration. A rigorous treatment of chemical shifts and pH variation data with lanthanide concentration is presented. Two different forms of the peptide ligand, forming simultaneously two complexes, were taken into account. At low pH values the cation is only coordinated at the carboxylate site of the ligand in a weak complex ( ?2 = 6) whereas in neutral solution a stronger complex ( ?1 = 37) is present as a consequence of the deprotonation of the imidazole ring. The computation of induced bound shifts † 2 and ?1 for resonating nuclei of the peptide in both forms yields consistent figures. These provide the experimental basis for a conformational model which is usually not obtainable for labile complexes with low stability constants.

Mossoyan, J.; Asso, M.; Benlian, D.

9

Shift reagents for multidimensional ion mobility spectrometry-mass spectrometry analysis of complex peptide mixtures: evaluation of 18-crown-6 ether complexes.  

PubMed

18-Crown-6 ether (18C6) is evaluated as a shift reagent for multidimensional ion mobility spectrometry-mass spectrometry (IMS-IMS-MS) analyses of tryptic protein digests. In this approach, 18C6 is spiked into the solution-phase mixture and noncovalent peptide-crown ion complexes are formed by electrospraying the mixture into the gas phase. After an initial mobility separation in the first IMS drift region, complexes of similar mobility are selected and dissociated via collisional activation prior to entering the second drift region. These dissociation products (including smaller complexes, naked peptide ions, charge transfer products, and fragment ions) differ in mobility from their precursor ion complexes and (in favorable cases) from one another, allowing the mixture to resolve further in the second IMS region. We estimate an IMS-IMS peak capacity of ~2400 when shift reagents are employed. The approach is illustrated by examining a tryptic digest of cytochrome c and by identifying a peptide out of a complex mixture obtained by digestion of human plasma proteins. Disadvantages arising from increased complexity of data sets as well as other advantages of this approach are considered. PMID:21609128

Bohrer, Brian C; Clemmer, David E

2011-07-01

10

Lanthanide-Polyaminopolycarboxylate Complexation Kinetics in High Lactate Media: Investigating the Aqueous Phase of TALSPEAK .  

E-print Network

??In advanced nuclear fuel reprocessing schemes, the TALSPEAK (Trivalent Actinide Lanthanide Separation with Phosphorus-reagent Extraction from Aqueous Komplexes) process has been proposed as a means… (more)

[No author

2013-01-01

11

Secret Lanthanides  

PubMed Central

Abstract Lanthanides are a group of 15 chemical elements which, together with their salts, have come to be used in the last decade as homoeopathic remedies. The effective introduction of lanthanides and their salts into the clinical use, as homoeopathic remedies was based on the idea of Jan Scholten, MD to relate their physicochemical properties shown in the periodic table of elements to their homoeopathic potential. The lanthanides and their salts were prepared as homoeopathic remedies by Pharmacist Robert Münz. PMID:25408760

Sturza, CM

2014-01-01

12

Characterization of a lanthanide complex encapsulated with MRI contrast agents into liposomes for biosensor imaging of redundant deviation in shifts (BIRDS).  

PubMed

Purposely designed magnetic resonance imaging (MRI) probes encapsulated in liposomes, which alter contrast by their paramagnetic effect on longitudinal (T1) and transverse (T2) relaxation times of tissue water, hold promise for molecular imaging. However, a challenge with liposomal MRI probes that are solely dependent on enhancement of water relaxation is lack of specific molecular readouts, especially in strong paramagnetic environments, thereby reducing the potential for monitoring disease treatment (e.g., cancer) beyond the generated MRI contrast. Previously, it has been shown that molecular imaging with magnetic resonance is also possible by detecting the signal of non-exchangeable protons emanating from paramagnetic lanthanide complexes themselves [e.g., TmDOTP(5-), which is a Tm(3+)-containing biosensor based on a macrocyclic chelate 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylene phosphonate), DOTP(5-)] with a method called biosensor imaging of redundant deviation in shifts (BIRDS). Here, we show that BIRDS is useful for molecular imaging with probes like TmDOTP(5-) even when they are encapsulated inside liposomes with ultrastrong T1 and T2 contrast agents (e.g., Magnevist and Molday ION, respectively). We demonstrate that molecular readouts such as pH and temperature determined from probes like TmDOTP(5-) are resilient, because the sensitivity of the chemical shifts to the probe's environment is not compromised by the presence of other paramagnetic agents contained within the same nanocarrier milieu. Because high liposomal encapsulation efficiency allows for robust MRI contrast and signal amplification for BIRDS, nanoengineered liposomal probes containing both monomers, TmDOTP(5-) and paramagnetic contrast agents, could allow high spatial resolution imaging of disease diagnosis (with MRI) and status monitoring (with BIRDS). PMID:25304046

Maritim, Samuel; Huang, Yuegao; Coman, Daniel; Hyder, Fahmeed

2014-12-01

13

The simultaneous binding of lanthanide and N-acetylglucosamine inhibitors to hen egg-white lysozyme in solution by 1H and 13C nuclear magnetic resonance.  

PubMed Central

Lanthanide ions and the N-acetylglucosamine (GlcNAc) sugars are able to bind simultaneously to hen egg-white lysozyme (EC 3.2.1.17). The present study characterizes the properties of the ternary complexes with lysozyme, which involve up to seven paramagnetic lanthanides and two diamagnetic lanthanides, together with alpha GlcNAc, beta GlcNAc, alpha MeGlcNAc and beta MeGlcNAc. pH titrations and binding titrations of the GlcNAc sugars with lysozyme-La(III) complexes show that the GlcNAc sugars bind to at least two independent sites and that one of them competes with La(III) for binding to lysozyme. Given the known binding site of lanthanides at Asp-52 and Glu-35, the competitive binding site of GlcNAc is identified as subsite E. A simple analysis of the paramagnetic-lanthanide-induced shifts shows that the GlcNAc sugar binds in subsite C, in accordance with crystallographic results [Perkins, Johnson, Machin & Phillips (1979) Biochem. J. 181, 21-36]. This finding was refined by several computer analyses of the lanthanide-induced shifts of 17 proton and carbon resonances of beta MeGlcNAc. Good fits were obtained for all the signals, except for two that were affected by exchange broadening phenomena. No distinction could be made between a fit for a two-position model of Ln(III) binding with axial symmetry to lysozyme, according to the crystallographic result, or a one-position model with axial symmetry where the Ln(III) is positioned mid-way between Asp-52 and Glu-35. Although this work establishes the feasibility of lanthanide shift reagents for study of protein-ligand complexes, further work is required to establish the manner in which lanthanides bind to lysozyme in solution. PMID:7305947

Perkins, S J; Johnson, L N; Phillips, D C; Dwek, R A

1981-01-01

14

Method bacterial endospore quantification using lanthanide dipicolinate luminescence  

NASA Technical Reports Server (NTRS)

A lanthanide is combined with a medium to be tested for endospores. The dipicolinic acid released from the endospores binds the lanthanides, which have distinctive emission (i.e., luminescence) spectra, and are detected using photoluminescence. The concentration of spores is determined by preparing a calibration curve generated from photoluminescence spectra of lanthanide complex mixed with spores of a known concentration. A lanthanide complex is used as the analysis reagent, and is comprised of lanthanide ions bound to multidentate ligands that increase the dipicolinic acid binding constant through a cooperative binding effect with respect to lanthanide chloride. The resulting combined effect of increasing the binding constant and eliminating coordinated water and multiple equilibria increase the sensitivity of the endospore assay by an estimated three to four orders of magnitude over prior art of endospore detection based on lanthanide luminescence.

Ponce, Adrian (Inventor); Venkateswaran, Kasthuri J. (Inventor); Kirby, James Patrick (Inventor)

2007-01-01

15

Luminescent lanthanide chelates and methods of use  

DOEpatents

The invention provides lanthanide chelates capable of intense luminescence. The celates comprise a lanthanide chelator covalently joined to a coumarin-like or quinolone-like sensitizer. Exemplary sensitzers include 2- or 4-quinolones, 2- or 4-coumarins, or derivatives thereof e.g. carbostyril 124 (7-amino-4-methyl-2-quinolone), coumarin 120 (7-amino-4-methyl-2-coumarin), coumarin 124 (7-amino-4-(trifluoromethyl)-2-coumarin), aminomethyltrimethylpsoralen, etc. The chelates form high affinity complexes with lanthanides, such as terbium or europium, through chelator groups, such as DTPA. The chelates may be coupled to a wide variety of compounds to create specific labels, probes, diagnostic and/or therapeutic reagents, etc. The chelates find particular use in resonance energy transfer between chelate-lanthanide complexes and another luminescent agent, often a fluorescent non-metal based resonance energy acceptor. The methods provide useful information about the structure, conformation, relative location and/or interactions of macromolecules.

Selvin, Paul R. (Berkeley, CA); Hearst, John (Berkeley, CA)

1997-01-01

16

Separation of lanthanides using ion-interaction chromatography with HDEHP coated columns  

Microsoft Academic Search

A rapid and high resolution separation of lanthanides by HPLC technique has been developed using Di-(2-ethylhexyl) phosphoric acid (HDEHP) coated reverse phase column and a-hydroxy isobutyric acid as the complexing reagent for elution. A gradient elution technique has been developed for achieving the separation of the entire lanthanide series. Isocratic elution procedure has also been developed for the separation of

N. Sivaraman; R. Kumar; S. Subramaniam; P. R. Vasudeva Rao

2002-01-01

17

Lanthanide-halide based humidity indicators  

DOEpatents

The present invention discloses a lanthanide-halide based humidity indicator and method of producing such indicator. The color of the present invention indicates the humidity of an atmosphere to which it is exposed. For example, impregnating an adsorbent support such as silica gel with an aqueous solution of the europium-containing reagent solution described herein, and dehydrating the support to dryness forms a substance with a yellow color. When this substance is exposed to a humid atmosphere the water vapor from the air is adsorbed into the coating on the pore surface of the silica gel. As the water content of the coating increases, the visual color of the coated silica gel changes from yellow to white. The color change is due to the water combining with the lanthanide-halide complex on the pores of the gel.

Beitz, James V. (Hinsdale, IL); Williams, Clayton W. (Chicago, IL)

2008-01-01

18

Ionization Energies of Lanthanides  

ERIC Educational Resources Information Center

This article describes how data are used to analyze the pattern of ionization energies of the lanthanide elements. Different observed pathways of ionization between different ground states are discussed, and the effects of pairing, exchange, and orbital interactions on ionization energies of the lanthanides are evaluated. When all the above…

Lang, Peter F.; Smith, Barry C.

2010-01-01

19

Citrate-based {open_quotes}Talspeak{close_quotes} actinide-lanthanide separation process  

SciTech Connect

Lanthanide elements are produced in relatively high yield by fission of {sup 235}U. Almost all the lanthanide isotopes decay to stable nonradioactive lanthanide isotopes in a relatively short time. Consequently, it is highly advantageous to separate the relatively small actinide fraction from the relatively large quantities of lanthanide isotopes. The TALSPEAK process (Trivalent Actinide Lanthanide Separations by Phosphorus-reagent Extraction from Aqueous Complexes) is one of the few means available to separate the trivalent actinides from the lanthanides. Previous work based on the use of lactic or glycolic acid has shown deleterious effects of some impurity ions such as zirconium(IV), even at concentrations on the order of 10{sup {minus}4} M. Other perceived problems were the need to maintain the pH and reagent concentrations within a narrow range and a significant solubility of the organic phase at high carboxylic acid concentrations. The authors` cold experiments showed that replacing the traditional extractants glycolic or lactic acid with citric acid eliminates or greatly reduces the deleterious effects produced by impurities such as zirconium. An extensive series of batch tests was done using a wide range of reagent concentrations at different pH values, temperatures, and contact times. The results demonstrated that the citrate-based TALSPEAK can tolerate appreciable changes in pH and reagent concentrations while maintaining an adequate lanthanide extraction. Experiments using a three-stage glass mixer-settler showed a good lanthanide extraction, appropriate phase disengagement, no appreciable deleterious effects due to the presence of impurities such as zirconium, excellent pH buffering, and no significant loss of organic phase.

Del Cul, G.D.; Toth, L.M.; Bond, W.D. [Oak Ridge National Lab., TN (United States)] [and others

1997-01-01

20

Handling Pyrophoric Reagents  

SciTech Connect

Pyrophoric reagents are extremely hazardous. Special handling techniques are required to prevent contact with air and the resulting fire. This document provides several methods for working with pyrophoric reagents outside of an inert atmosphere.

Alnajjar, Mikhail S.; Haynie, Todd O.

2009-08-14

21

The Lanthanide Contraction Revisited  

SciTech Connect

A complete, isostructural series of lanthanide complexes (except Pm) with the ligand TREN-1,2-HOIQO has been synthesized and structurally characterized by means of single-crystal X-ray analysis. All complexes are 1D-polymeric species in the solid state, with the lanthanide being in an eight-coordinate, distorted trigonal-dodecahedral environment with a donor set of eight unique oxygen atoms. This series constitutes the first complete set of isostructural lanthanide complexes with a ligand of denticity greater than two. The geometric arrangement of the chelating moieties slightly deviates across the lanthanide series, as analyzed by a shape parameter metric based on the comparison of the dihedral angles along all edges of the coordination polyhedron. The apparent lanthanide contraction in the individual Ln-O bond lengths deviates considerably from the expected quadratic decrease that was found previously in a number of complexes with ligands of low denticity. The sum of all bond lengths around the trivalent metal cation, however, is more regular, showing an almost ideal quadratic behavior across the entire series. The quadratic nature of the lanthanide contraction is derived theoretically from Slater's model for the calculation of ionic radii. In addition, the sum of all distances along the edges of the coordination polyhedron show exactly the same quadratic dependency as the Ln-X bond lengths. The universal validity of this coordination sphere contraction, concomitant with the quadratic decrease in Ln-X bond lengths, was confirmed by reexamination of four other, previously published, almost complete series of lanthanide complexes. Due to the importance of multidentate ligands for the chelation of rare-earth metals, this result provides a significant advance for the prediction and rationalization of the geometric features of the corresponding lanthanide complexes, with great potential impact for all aspects of lanthanide coordination.

Seitz, Michael; Oliver, Allen G.; Raymond, Kenneth N.

2007-04-19

22

REAGENT-FREE ION-EXCHANGE SEPARATIONS  

Microsoft Academic Search

This paper reviews the development of reagent-free (and therefore ecologically clean) ion-exchange separation techniques. These methods are based on the shift of the ion exchanger selectivity induced by the modulation of some physico-chemical parameters of the system such as temperature, solution concentration, pH, etc. This approach avoids the use of auxiliary reagents and additional operations such as the regeneration of

Vladimir I. Gorshkov; Vladimir A. Ivanov

1999-01-01

23

Surface Science Letters Surface X-ray emission from lanthanide metals  

E-print Network

Surface Science Letters Surface X-ray emission from lanthanide metals F. Huubinger a , A. The energy separation of surface and bulk XE peaks is explained by the surface core-level shift of La new opportunities in studying surface phenomena in lanthanide metals and com- pounds. Ã? 2002 Elsevier

Grigoriev, Alexei

24

Evaluation of Multiple-Quantum-Filtered 23Na NMR in Monitoring Intracellular Na Content in the Isolated Perfused Rat Heart in the Absence of a Chemical-Shift Reagent  

NASA Astrophysics Data System (ADS)

The feasibility of employing triple-quantum-filtered (TQF) or double-quantum-filtered (DQF) 23Na NMR spectra to monitor intracellular Na (Na in) content in isolated rat hearts perfused in the absence of a chemical-shift reagent (SR) was investigated. This necessitated characterization of the following: first, the pool of Na inrepresented by the intracellular TQF (TQF in) spectrum; second, the maximum extent to which altered transverse relaxation times affect TQF inspectral amplitudes; and finally, the situations for which the SR-free method can reliably be applied. The rates of increase in peak amplitudes of both intracellular TQF spectra, adjusted for changes in both fast ( T2f) and slow ( T2s) transverse relaxation times, and intracellular single-quantum (SQ in) spectra were identical during no-flow ischemia, indicating that TQF inand SQ inspectra represent the same Na inpopulation. Addition of an Na/K ATPase inhibitor, ouabain (?500 ? M), and no-flow ischemia induced similar rates of increase of Na incontent. However, the Na inlevel for which the T2values started to increase was lower for ischemic (<140% of preischemic values) than for ouabain-exposed (>165%) hearts, which is consistent with the known earlier onset of intracellular swelling in ischemic hearts. Exposure of hearts to hyperosmotic perfusate (200 m Msucrose) increased [Na in], due to a decreased cell volume and an unchanged Na incontent, but caused a decrease in T2values, a trend opposite to that observed with exposure of hearts to ouabain or ischemia. T2values therefore consistently correlated only with cell volume, not with Na incontent or concentration, indicating an important role for intracellular macromolecule concentration in modulating transverse relaxation behavior. The combined effect of ischemia-induced increases in T2values and their inhomogeneous broadened forms was an ˜6% overestimation of Na incontent from amplitudes of SR-aided TQF inspectra, indicating negligible effect of transverse relaxation-dependent alterations on TQF inspectral amplitudes. Thus, Na incontent may be reliably determined from SR-free TQF spectra when the contribution from extracellular Na does not appreciably vary, such as during constant pressure perfusion. Following complete reduction in perfusion pressure, both SR-free TQF and DQF spectra respond to increases in Na incontent. However, SR-free DQF NMR provides an estimate of Na incontent much closer to that provided by the SR-aided method, due to the appreciable decrease of the extracellular DQF signal resulting from destructive interference between second- and third-rank tensors.

Tauskela, Joseph S.; Dizon, José M.; Whang, John; Katz, José

1997-07-01

25

RAS Reference Reagents  

Cancer.gov

Posted: 09/22/2014 Posted: 09/22/2014 RAS Reference Reagents Reference Reagents Group An important priority of the RAS Initiative is to distribute highly validated materials and methods to the world-wide community of RAS researchers. Two panels of

26

Luminescent macrocyclic lanthanide complexes  

DOEpatents

The present invention provides a novel class of macrocyclic compounds as well as complexes formed between a metal (e.g., lanthanide) ion and the compounds of the invention. Preferred complexes exhibit high stability as well as high quantum yields of lanthanide ion luminescence in aqueous media without the need for secondary activating agents. Preferred compounds incorporate hydroxy-isophthalamide moieties within their macrocyclic structure and are characterized by surprisingly low, non-specific binding to a variety of polypeptides such as antibodies and proteins as well as high kinetic stability. These characteristics distinguish them from known, open-structured ligands.

Raymond, Kenneth N. (Berkeley, CA); Corneillie, Todd M. (Campbell, CA); Xu, Jide (Berkeley, CA)

2012-05-08

27

Reference Reagents Group  

Cancer.gov

The goal of our project is the production and distribution of qualified DNA vectors, cell lines, viruses, and proteins, initially as resources for the Frederick National Laboratory for Cancer Research RAS mission and ultimately as high-quality reagents to supply to the larger RAS community. Eventually we hope also to generate reagents specifically requested by the extramural community. Sequence-verified libraries of RAS and RAS-related genes in Gateway combinatorial cloning vectors are available now.

28

Complexation of lanthanides and actinides by acetohydroxamic acid  

SciTech Connect

Acetohydroxamic acid (AHA) has been proposed as a suitable reagent for the complexant-based, as opposed to reductive, stripping of plutonium and neptunium ions from the tributylphosphate solvent phase in advanced PUREX or UREX processes designed for future nuclear-fuel reprocessing. Stripping is achieved by the formation of strong hydrophilic complexes with the tetravalent actinides in nitric acid solutions. To underpin such applications, knowledge of the complexation constants of AHA with all relevant actinide (5f) and lanthanide (4f) ions is therefore important. This paper reports the determination of stability constants of AHA with the heavier lanthanide ions (Dy-Yb) and also U(IV) and Th(IV) ions. Comparisons with our previously published AHA stability-constant data for 4f and 5f ions are made. (authors)

Taylor, R.J. [British Technology Centre, Nexia Solutions, Sellafield, Seascale, CA20 1PG (United Kingdom); Sinkov, S.I. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Choppin, G.R. [Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL (United States)

2008-07-01

29

Advancing the scientific basis of trivalent actinide-lanthanide separations  

SciTech Connect

For advanced fuel cycles designed to support transmutation of transplutonium actinides, several options have been demonstrated for process-scale aqueous separations for U, Np, Pu management and for partitioning of trivalent actinides and fission product lanthanides away from other fission products. The more difficult mutual separation of Am/Cm from La-Tb remains the subject of considerable fundamental and applied research. The chemical separations literature teaches that the most productive alternatives to pursue are those based on ligand donor atoms less electronegative than O, specifically N- and S-containing complexants and chloride ion (Cl{sup -}). These 'soft-donor' atoms have exhibited usable selectivity in their bonding interactions with trivalent actinides relative to lanthanides. In this report, selected features of soft donor reagent design, characterization and application development will be discussed. The roles of thiocyanate, aminopoly-carboxylic acids and lactate in separation processes are detailed. (authors)

Nash, K.L. [Washington State University, Department of Chemistry, PO Box 644630, Pullman, WA 99164-4630 (United States)

2013-07-01

30

Reagents, Compositions, Weight Loss  

NSDL National Science Digital Library

This is a short experimental study of what happens to aluminum hydroxide, silicic acid, magnesium oxide, and calcium carbonate (or reagents of instructors choice) when they are heated to 110 and 1200 degrees. Students determine the formula and calculate the mole percent and weight percent of each element and oxide in each reagent. They heat the samples and calculate percentage weight loss or gain. Finally, they write a lab report summarizing their results. Be sure to have students save their samples for later use in a lab that introduces X-ray diffraction.

Perkins, Dexter

31

Determination of the theoretical rate constants for the reduction reactions of lanthanide ions by hydrated electrons  

Microsoft Academic Search

The mechanism of the reduction reaction of lanthanide(III) ions by hydrated electrons in polar solvents has been investigated.\\u000a The theoretical rate constants for the reaction of hydrated electrons with a number of lanthanide ions have been calculated\\u000a using the energy gap laws of the charge shift reaction(D+?A?D?A+) and compared with experimental values. With these results, we have explained the large

Kwang-Pill Lee; Keung-Shik Park; Duck-Won Kang; Yasuhiro Yamada; Shin-ichi Ohno

1998-01-01

32

Tropomyosin isoforms and reagents  

PubMed Central

Tropomyosins are rod-like dimers which form head-to-tail polymers along the length of actin filaments and regulate the access of actin binding proteins to the filaments.1 The diversity of tropomyosin isoforms, over 40 in mammals, and their role in an increasing number of biological processes presents a challenge both to experienced researchers and those new to this field. The increased appreciation that the role of these isoforms expands beyond that of simply stabilizing actin filaments has lead to a surge of reagents and techniques to study their function and mechanisms of action. This report is designed to provide a basic guide to the genes and proteins and the availability of reagents which allow effective study of this family of proteins. We highlight the value of combining multiple techniques to better evaluate the function of different tm isoforms and discuss the limitations of selected reagents. Brief background material is included to demystify some of the unfortunate complexity regarding this multi-gene family of proteins including the unconventional nomenclature of the isoforms and the evolutionary relationships of isoforms between species. Additionally, we present step-by-step detailed experimental protocols used in our laboratory to assist new comers to the field and experts alike. PMID:22069507

Schevzov, Galina; Whittaker, Shane P; Fath, Thomas; Lin, Jim JC

2011-01-01

33

Citrate based ``TALSPEAK`` lanthanide-actinide separation process  

SciTech Connect

The potential hazard posed to future generations by long-lived radionuclides such as the transuranic elements (TRU) is perceived as a major problem associated with the use of nuclear power. TRU wastes have to remain isolated from the environment for ``geological`` periods of time. The costs of building, maintaining, and operating a ``geological TRU repository`` can be very high. Therefore, there are significant economical advantages in segregating the relatively low volume of TRU wastes from other nuclear wastes. The chemical behavior of lanthanides and actinides, 4f and 5f elements respectively, is rather similar. As a consequence, the separation of these two groups is difficult. The ``TALSPEAK`` process (Trivalent Actinide Lanthanide Separations by Phosphorus-reagent Extraction from Aqueous Complexes) is one of the few means available to separate the trivalent actinides from the lanthanides. The method is based on the preferential complexation of the trivalent actinides by an aminopolyacetic acid. Cold experiments showed that by using citric acid the deleterious effects produced by impurities such as zirconium are greatly reduced.

Del Cul, G.D.; Bond, W.D.; Toth, L.M.; Davis, G.D.; Dai, S.; Metcalf, D.H.

1994-09-01

34

Rapid separation of beryllium and lanthanide derivatives by capillary gas chromatography.  

PubMed

DOI: 10.1002/jssc.201200537 Europium(III) derivative formed by reaction of the europium ion with a fluorinated ?-diketonate reagent and a neutral donor. The resulting non-polar, thermally stable, and luminescent derivative partitions into cyclohexane upon formation and can be subjected to high-resolution capillary gas chromatography. This approach is used to separate derivatives of lanthanides that are adjacent to one another in the periodic table. In addition, an on-fiber SPME derivatization/concentration GC/MS method that uses a fiber preloaded with the same ?-diketonate reagent is described for the analysis of beryllium(II) ion. PMID:23065933

Harvey, Scott D; Lucke, Richard B; Douglas, Matt

2012-10-01

35

RP-IPC with a lactic acid modified eluent for separation and determination of lanthanide ions  

SciTech Connect

In this paper, a modified method for the separation and determination of Rare Earth Elements in solution is developed. Lanthanide ions were separated by Reversed-Phase Ion Pair Chromatography using a mobile phase gradient of pH and lactic acid concentration. A post-column reaction with 4-(2 pyridyl)azo resorcinol was carried out for the spectrophotometric detection of solutes. The derivatizing reagent composition was optimized for good solute sensitivity and long-term reagent stability. Method limitations due to inadequate instrumentation are presented and discussed.

Vera-Avila, L.E.; Camacho, E. (Analytical Chemistry Dept., Facultad de Quimica, Univ. Nacional Autonoma de Mexico, 04510 D.F. (Mexico))

1992-01-01

36

Use of soft heterocyclic N-donor ligands to separate actinides and lanthanides.  

PubMed

The removal of the most long-lived radiotoxic elements from used nuclear fuel, minor actinides, is foreseen as an essential step toward increasing the public acceptance of nuclear energy as a key component of a low-carbon energy future. Once removed from the remaining used fuel, these elements can be used as fuel in their own right in fast reactors or converted into shorter-lived or stable elements by transmutation prior to geological disposal. The SANEX process is proposed to carry out this selective separation by solvent extraction. Recent efforts to develop reagents capable of separating the radioactive minor actinides from lanthanides as part of a future strategy for the management and reprocessing of used nuclear fuel are reviewed. The current strategies for the reprocessing of PUREX raffinate are summarized, and some guiding principles for the design of actinide-selective reagents are defined. The development and testing of different classes of solvent extraction reagent are then summarized, covering some of the earliest ligand designs right through to the current reagents of choice, bis(1,2,4-triazine) ligands. Finally, we summarize research aimed at developing a fundamental understanding of the underlying reasons for the excellent extraction capabilities and high actinide/lanthanide selectivities shown by this class of ligands and our recent efforts to immobilize these reagents onto solid phases. PMID:22867058

Hudson, Michael J; Harwood, Laurence M; Laventine, Dominic M; Lewis, Frank W

2013-04-01

37

Trivalent Actinide and Lanthanide Separations by Dialkyl?Substituted Diphosphonic Acids  

Microsoft Academic Search

The dialkyl?substituted diphosphonic acids are powerful solvent extraction reagents for actinide separation and preconcentration from biological, environmental, and nuclear waste samples. In spite of the intensive scrutiny of the solvent extraction properties of these compounds, only the extraction of Eu(III) and Am(III), among the lanthanides and trivalent actinides, has been investigated thus far. In this work, we report the extraction

R. Chiarizia; D. R. McAlister; A. W. Herlinger

2005-01-01

38

Luminescent Lanthanide Reporters for High-Sensitivity Novel Bioassays.  

SciTech Connect

Biological imaging and assay technologies rely on fluorescent organic dyes as reporters for a number of interesting targets and processes. However, limitations of organic dyes such as small Stokes shifts, spectral overlap of emission signals with native biological fluorescence background, and photobleaching have all inhibited the development of highly sensitive assays. To overcome the limitations of organic dyes for bioassays, we propose to develop lanthanide-based luminescent dyes and demonstrate them for molecular reporting applications. This relatively new family of dyes was selected for their attractive spectral and chemical properties. Luminescence is imparted by the lanthanide atom and allows for relatively simple chemical structures that can be tailored to the application. The photophysical properties offer unique features such as narrow and non-overlapping emission bands, long luminescent lifetimes, and long wavelength emission, which enable significant sensitivity improvements over organic dyes through spectral and temporal gating of the luminescent signal.Growth in this field has been hindered due to the necessary advanced synthetic chemistry techniques and access to experts in biological assay development. Our strategy for the development of a new lanthanide-based fluorescent reporter system is based on chelation of the lanthanide metal center using absorbing chromophores. Our first strategy involves %22Click%22 chemistry to develop 3-fold symmetric chelators and the other involves use of a new class of tetrapyrrole ligands called corroles. This two-pronged approach is geared towards the optimization of chromophores to enhance light output.

Anstey, Mitchell; Fruetel, Julia A.; Foster, Michael E.; Hayden, Carl C.; Buckley, Heather L.; Arnold, John

2013-09-01

39

PROTEIN MEASUREMENT WITH THE FOLIN PHENOL REAGENT*  

E-print Network

or potassium tartrabe. Reagent C, alkaline copper solution. Mix 50 ml. of Reagent A with 1 ml. of Reagent B of NaOH. Re- agent E, diluted Folin reagent. Titrate Folin-Ciocalteu phenol reagent ((II), Eimer of this titration dilute the Folin reagent (about 2-fold) to make it 1 N in acid. Working standards may be prepared

Kroll, Kristen L.

40

Calibration beads containing luminescent lanthanide ion complexes  

EPA Science Inventory

The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including mi...

41

New types of lanthanide complexes  

SciTech Connect

Three new types of lanthanide (Ln) complexes, namely, the first examples of homodinuclear macrocyclic lanthanide complexes, novel binary and ternary gaseous polyatomic lanthanide oxides and new lanthanide oxalato complexes are described in chapters one, two and three respectively. The homodinuclear complexes are 2:2 condensation products of 2,6-diformyl-p-cresol and triethylenetetramine templated by Ln(NO/sub 3/)/sub 3/ and Ln(ClO/sub 4/)/sub 3/. The complexes are dimorphic, and are off-white (the more stable form) when they are obtained from dilute solutions and orange if they arise from more concentrated reactants. The complexes were characterized by elemental analysis, fast atom bombardment mass spectrometry (FAB MS), electronic absorption and IR spectroscopy, thermogravimetry along with preliminary spectroscopic studies using electron paramagnetic resonance, magnetic susceptibility and luminescence. The orange complexes exhibit more antiferromagnetic exchange interactions, low Ln/sup 3 +/magnetic moments and multi-exponential luminescence decay kinetics, whereas the off-white complexes show single exponential luminescence decay and free ion magnetic moments. At low temperatures and in presence of excess triethylenetetramine, solvated light lanthanide mononuclear complexes of a 1:1 acyclic Schiff base acetal were isolated and the structure of one of these was confirmed by single crystal x-ray diffraction crystallography.

Kahwa, I.A.K.

1986-01-01

42

Recovery of uranium and lanthanides  

SciTech Connect

The authors discuss how solutions containing Ca(H{sub 2}PO{sub 4}){sub 2}-Ca(NO{sub 3}){sub 2-H}{sub 2}O and Ca(H{sub 2}PO{sub 4}){sub 2}-CaCI-H{sub 2}O obtained by leaching phosphate rock in situ or in dumps can be treated for uranium and lanthanides recovery prior to P{sub 2}O{sub 5}recovery as follows: In a nitrate system, uranium is first extracted by a mixture of bis(2-ethylehexl)phosphoric acid (D2EHPA) and tributyl phosphate (TBP) in hexane followed by the extraction of the lanthanides with TBP. In a chloride system, uranium is first extracted by the same mixture, D2EHPA + TBP, followed by the extraction of lanthanides with D2EHPA in toluene.

Awadalla, F.T.; Habashi, F. (Laval Univ., Dept. of Mining and Metallurgy, Quebec City (CA))

1989-07-01

43

Separation and determination of lanthanides, thorium and uranium using a dual gradient in reversed-phase liquid chromatography.  

PubMed

Separation and determination of lanthanides, Th and U is of great relevance in different fields of science and technology. Reversed-phase high-performance liquid chromatography (RP-HPLC) using alpha-hydroxy isobutyric acid (alpha-HIBA) as an eluent on reversed-phase column modified to cation exchanger has been reported to achieve the separation. However, under those conditions, Th and U are eluted amongst lanthanides, making their quantification difficult due to overlapping with some of the lanthanides peaks. In this work, different chromatographic parameters (concentrations of eluent and ion interaction reagent, pH, etc.) were studied systematically to arrive at optimum chromatographic conditions. Using the dual (concentration and pH) gradient conditions, lanthanides, Th and U could be separated in 11 min by RP-HPLC with sequential elution of Th and U after the elution of all the lanthanides. The separation methodology was tested using SY-3 rock sample for the separation and determination of lanthanides, Th and U. The method allows an accurate determination of these elements in a single run using a single column. Also, the method is fast and cost-effective compared to the reported methods. PMID:15527129

Raut, Narendra M; Jaison, P G; Aggarwal, Suresh K

2004-10-15

44

Perturbation of the racemic equilibrium between D{sub 3} lanthanide complexes through the addition of sugars  

SciTech Connect

The enantiomeric excess of a lanthanide (III) 2,6-pyridinecarboxylate complex in the presence of chiral sugars was monitored using luminescence spectroscopy. While no structural change was observed for the RE complexes, correlation between sugar concentration and enantiomeric excess was found to be linear. A model based on equilibrium association between the complexes and sugar molecules in the outer sphere is used to explain the shift in the enantiomeric excess for the lanthanide complexes.

Huskowska, E.; Riehl, J.P. [Michigan Technological Univ., Houghton, MI (United States)

1995-10-25

45

Routes to monomeric lanthanide alkoxides  

Microsoft Academic Search

The following contribution deals with lanthanide alkoxide chemistry under the aspects of organic ligand synthesis — metal complexation — application. Special emphasis is put on the design and synthesis of tailor-made ligand environments. In particular, the methodology of donor-functionalization opens the way to creating several intriguing properties simultaneously — prerequisites for potential applications as highly selective catalysts for organic synthesis

Reiner Anwander

46

21 CFR 866.4100 - Complement reagent.  

...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunology Laboratory Equipment and Reagents § 866.4100 Complement reagent. (a)...

2014-04-01

47

21 CFR 866.4100 - Complement reagent.  

Code of Federal Regulations, 2012 CFR

...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunology Laboratory Equipment and Reagents § 866.4100 Complement reagent. (a)...

2012-04-01

48

21 CFR 866.4100 - Complement reagent.  

Code of Federal Regulations, 2010 CFR

...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunology Laboratory Equipment and Reagents § 866.4100 Complement reagent. (a)...

2010-04-01

49

Reagents for Identifying 'Mycoplasma pneumoniae'.  

National Technical Information Service (NTIS)

The invention is related to reagents which specifically recognize the human pathogen Mycoplasma pneumoniae and no other Mycoplasma species or organism belonging to the class Mollicutes. More particularly, the present invention is related to an immunoassay...

L. D. Olson

1989-01-01

50

A counter current experiment for the separation of trivalent actinides and lanthanides by the SETFICS process  

SciTech Connect

The STFICS process, a variation of TRUEX process, was developed for the recovery of Am and Cm from acidic waste solution and the separation of actinides(III) and light lanthanides. The process uses the general TRUEX solvent as the extracting reagent and a DTPA-sodium nitrate solution for selective stripping of actinides(III). The basic flow sheet is composed of four steps: extraction-scrubbing; acid stripping; actinide(III) stripping; and lanthanide stripping. To demonstrate the usefulness of the SETFICS process, a counter current experiment was conducted using a real TRUEX product solution. Americium and curium were successfully recovered with a solution of 0.05 M DTPA-4 M NaNO{sub 3} (pH 2.0). Although the actinide(III) product solution contained Sm and Eu, the decontamination factor of {sup 144}Ce/{sup 241}Am was 72, and most of the light lanthanides, specifically La, Ce, Pr, Nd, were removed. At least 80% of the lanthanides were separated from the Am and Cm end products. In order to minimize the acidity in the actinide(III) stripping step, the nitric acid which extracted with the trivalent metals was previously removed with a solution of 0.5 M NaNO{sub 3} (pH 2.0) in the acid stripping step.

Koma, Yoshikazu; Watanabe, Masayuki; Nemoto, Shinichi; Tanaka, Yasumasa [Power Reactor and Nuclear Fuel Development Corp., Tokai, Ibaraki (Japan)

1998-11-01

51

Separation of Trivalent Actinides from Lanthanides in an Acetate Buffer Solution Using Cyanex 301  

SciTech Connect

The separation of trivalent actinides from the lanthanides using the active extractant in the Cyanex 301 reagent, bis(2,4,4-trimethylpentyl)dithiophosphinic acid, was studied. Specifically, the extractant was studied for an ammonium acetate/acetic acid buffered feed that would result from a transuranic separation process utilizing an ammonium acetate strip solution. Separation factors of 241Am from 154Eu with this extractant, as a function of total acetate concentration and pH, have been measured. Additionally, the extraction behavior of stable La, Ce, Pr, Nd, Sm, and Eu was measured. Separation factors were typically very high for Am from Eu at a pH ranging from 3.8 to 5.8 and a total acetate concentration ranging from 0.2 M to 1.0 M. However, separation factors across the lanthanide series varied considerably and resulted in separation of the lighter lanthanides from the heavier lanthanides at the higher pH’s.

Jack D. Law; Dean R. Peterman; Terry A. Todd; Richard D. Tillotson

2006-05-01

52

Separation factors of lanthanides extracted with dibutylphosphate  

Microsoft Academic Search

Extraction coefficients and separation factors of all lanthanides in the diluted aqueous HDBP—HNO3 system were determined in the temperature range 10–50 °C. Essential differences were noticed between the results obtained\\u000a for light (La—Gd) and heavy (Gd—Lu) lanthanides. It was found that the selectivity of the investigated system, in the case\\u000a of heavy lanthanides, is as high as that observed for

I. Fidelis; J. Krejzler

1976-01-01

53

Investigation of Gravity Lanthanide Separation Chemistry  

SciTech Connect

Lanthanides are common fission products and the ability to separate and quantify these elements is critical to rapid radiochemistry applications. Published lanthanide separations using Eichrom Ln Spec resin utilize an HCl gradient. Here it is shown that the efficacy and resolution of the separation is improved when a nitric acid gradient is used instead. The described method allows parallel processing of many samples in 1.5 hours followed by 60 minute counting for quantification of 9 isotopes of 7 lanthanide elements.

Payne, Rosara F.; Schulte, Shannon M.; Douglas, Matthew; Friese, Judah I.; Farmer, Orville T.; Finn, Erin C.

2011-03-01

54

Melting points of lanthanide trichlorides  

Microsoft Academic Search

Summary  The melting temperatures and absolute values of melting enthalpies of lanthanide trichlorides decrease from LaCl3to TbCl3and then increase to LuCl3. The preceding decrease cannot be explained by the lattice energies of the trichlorides, since they increase continuously\\u000a from the lanthanum to the lutetium compounds. However, it may be attributed to the structural features of the liquid state.\\u000a The liquids near

H. J. Seifert

2005-01-01

55

Taking advantage of luminescent lanthanide ions  

Microsoft Academic Search

Lanthanide ions possess fascinating optical properties and their discovery, first industrial uses and present high technological applications are largely governed by their interaction with light. Lighting devices (economical luminescent lamps, light emitting diodes), television and computer displays, optical fibres, optical amplifiers, lasers, as well as responsive luminescent stains for biomedical analysis, medical diagnosis, and cell imaging rely heavily on lanthanide

Jean-Claude G. Bunzli; Claude Piguet

2005-01-01

56

Chemical Amplification with Encapsulated Reagents  

NASA Technical Reports Server (NTRS)

Autocatalysis and chemical amplification are characteristic properties of living systems, and they give rise to behaviors such as increased sensitivity, responsiveness, and self-replication. Here we report a synthetic system in which a unique form of compartmentalization leads to nonlinear, autocatalytic behavior. The compartment is a reversibly formed capsule in which a reagent is sequestered. Reaction products displace the reagent from the capsule into solution and the reaction rate is accelerated. The resulting self-regulation is sensitive to the highly selective molecular recognition properties of the capsule.

Chen, Jian; Koemer, Steffi; Craig, Stephen; Lin, Shirley; Rudkevich, Dmitry M.; Rebek, Julius, Jr.

2002-01-01

57

ITP of lanthanides in microfluidic PMMA chip.  

PubMed

An ITP separation of eight lanthanides on a serpentine PMMA microchip with a tee junction and a 230-mm-long serpentine channel is described. The cover of the PMMA chip is 175 ?m thick so that a C(4) D in microchip mode can be used to detect the lanthanides as they migrate through the microchannel. Acetate and ?-hydroxyisobutyric acid are used as complexing agents to increase the electrophoretic mobility difference between the lanthanides. Eight lanthanides are concentrated within ? 6 min by ITP in the microchip using 10 mM ammonium acetate at pH 4.5 as the leading electrolyte and 10 mM acetic acid at ? pH 3.0 as the terminating electrolyte. In addition, a 2D numerical simulation of the lanthanides undergoing ITP in the microchip is compared with experimental results using COMSOL Multiphysics v4.3a. PMID:24258617

Cong, Yongzheng; Bottenus, Danny; Liu, Bingwen; Clark, Sue B; Ivory, Cornelius F

2014-03-01

58

Chiral tripode approach toward multiple anion sensing with lanthanide complexes  

Microsoft Academic Search

A chiral tripodal ligand was demonstrated to form a series of lanthanide complexes exhibiting multiple anion-sensing profiles, which incorporated a fluorescent quinoline and a stereo-controlled substituent in a tetradentate skeleton. This mainly gave 1:2 (lanthanide cation\\/ligand) complexes with lanthanide triflates but 1:1 complexes with lanthanide nitrates. Since addition of external guest anion dynamically changed the preferred stoichiometry, the chiral lanthanide

Miyuki Eiraku Masaki; Dharam Paul; Rie Nakamura; Yumiko Kataoka; Satoshi Shinoda; Hiroshi Tsukube

2009-01-01

59

[Supplies: inventory control and reagents].  

PubMed

The main relevant features useful for the management of reagents and consumables as well as documents to be developed to meet the requirements of the accreditation standard ISO/FDIS 15189-2012 are listed. This article is intended to help the medical laboratory to get mandatory accreditation. PMID:23765026

Szymanowicz, A

2013-06-01

60

Separation of actinides from lanthanides  

DOEpatents

An organic extracting solution and an extraction method useful for separating elements of the actinide series of the periodic table from elements of the lanthanide series, where both are in trivalent form is described. The extracting solution consists of a primary ligand and a secondary ligand, preferably in an organic solvent. The primary ligand is a substituted monothio-1,3-dicarbonyl, which includes a substituted 4-acyl-2-pyrazolin-5-thione, such as 4-benzoyl-2,4- dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (BMPPT). The secondary ligand is a substituted phosphine oxide, such as trioctylphosphine oxide (TOPO).

Smith, B.F.; Jarvinen, G.D.; Ryan, R.R.

1988-03-31

61

Separation of actinides from lanthanides  

DOEpatents

An organic extracting solution and an extraction method useful for separating elements of the actinide series of the periodic table from elements of the lanthanide series, where both are in trivalent form. The extracting solution consists of a primary ligand and a secondary ligand, preferably in an organic solvent. The primary ligand is a substituted monothio-1,3-dicarbonyl, which includes a substituted 4-acyl-2-pyrazolin-5-thione, such as 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (BMPPT). The secondary ligand is a substituted phosphine oxide, such as trioctylphosphine oxide (TOPO).

Smith, Barbara F. (Los Alamos, NM); Jarvinen, Gordon D. (Los Alamos, NM); Ryan, Robert R. (Los Alamos, NM)

1989-01-01

62

Lanthanides in the frame of Molecular Magnetism  

NASA Astrophysics Data System (ADS)

Molecular magnetism is producing new types of materials which cover up to date aspects of basic science together with possible applications. This article highlights recent results from the point of view of lanthanides which are now intensively used to produce single molecule magnets, single chain and single ion magnets. After a short introduction reminding the main steps of development of molecular magnetism, the basic properties of lanthanides will be covered highlighting important features which are enhanced by the electronic structure of lanthanides, like spin frustration and chirality, anisotropy and non collinear axes in zero and one dimensional materials. A paragraph of conclusions will discuss what has been done and theperspectives to be expected.

Gatteschi, D.

2014-07-01

63

Colour Reagent for Paper Chromatography of Steroids  

Microsoft Academic Search

FOR the paper chromatography of steroids several colour reagents are used, such as 2,4-dinitrophenyl-hydrazine, Zimmermann's reagent, phosphomolybdic acid, antimony trichloride, etc. Their common defect is that the reagent gives some colour with the paper itself, and so the contrast between spot and paper is too small. We have found that acid aniline phthalate in alcoholic solution-the reagent Partridge used for

A. Bodánszky; J. Kollonitsch

1955-01-01

64

DFTMP, an NMR reagent for assessing the near-neutral pH of biological samples.  

PubMed

A new NMR chemical shift standard and pH indicator, difluorotrimethylsilanylphosphonic acid (DFTMP), is described, and the utility of this reagent is demonstrated for in situ determination of pH in complex biofluids. The pH dependence of this reagent allows accurate in situ determination of aqueous solution pH to within an RMSE of 0.02 pH units over a pH range of 5 to 8. Advantages of this reagent over previously described pH-sensitive components include (1) lack of metal binding affinity, (2) minimal disturbance of endogenous spectral regions, and (3) the potential to function as a multinuclear pH indicator and chemical shift reference point for 19F, 1H, and 31P nuclei. This reagent will be generally useful for NMR experiments on biological systems where the pH needs to be accurately measured at the moment of data acquisition. PMID:16984154

Reily, Michael D; Robosky, Lora C; Manning, Matthew L; Butler, Andrew; Baker, John David; Winters, R Thomas

2006-09-27

65

21 CFR 866.3360 - Lymphocytic choriomeningitis virus serological reagents.  

... false Lymphocytic choriomeningitis virus serological reagents. 866.3360 Section...866.3360 Lymphocytic choriomeningitis virus serological reagents. (a) Identification. Lymphocytic choriomeningitis virus serological reagents are devices...

2014-04-01

66

21 CFR 866.3360 - Lymphocytic choriomeningitis virus serological reagents.  

Code of Federal Regulations, 2013 CFR

... false Lymphocytic choriomeningitis virus serological reagents. 866.3360 Section...866.3360 Lymphocytic choriomeningitis virus serological reagents. (a) Identification. Lymphocytic choriomeningitis virus serological reagents are devices...

2013-04-01

67

Stain Reagent Reversible Stain Kits  

E-print Network

are not visible before destain- ing with methanol/acetic acid to remove the characteristic background stainingGelCode ® Blue Stain Reagent GelCode ® SilverSNAP TM Stain GelCode ® E-Zinc TM Reversible Stain Kits Technical Review Gel Stains F E A T U R I N G . . . #12;P r o t e i n S t a i n i n g Only

Lebendiker, Mario

68

Synthesis of N-Fmoc-(2S,3S,4R)-3,4-dimethylglutamine. An Application of Lanthanide-Catalyzed Transamidation  

PubMed Central

N-Fmoc-(2S,3S,4R)-3,4-dimethylglutamine (6) was synthesized from t-butyl N-Boc-(2S,3S,4R)-dimethylpyroglutamate (13). This synthesis involved selective deprotection of a Boc group from a lactam nitrogen in the presence of a t-butyl ester, Fmoc protection of the lactam, and a lanthanide-catalyzed transamidation reaction of the Fmoc-protected lactam using ammonia and dimethylaluminum chloride. The scope of Lewis acid-catalyzed transamidation of acylated lactams was explored through the variation of lanthanide, lactam, acyl group, amine and aluminum reagent. The reactivity of various metal triflates was found to vary in the qualitative order: Yb?Sc>Er?Eu?Sm>Ce?AgI>CuII?Zn. Intriguingly, catalysis was only observed when ammonia was the nitrogen nucleophile; addition of other amidoaluminum complexes to acyl lactams was found to be insensitive to the addition of lanthanides. PMID:16050680

Calimsiz, Selcuk; Lipton, Mark A.

2006-01-01

69

FuGENE 6 Transfection Reagent: minimizing reagent-dependent side effects as analyzed by gene-  

E-print Network

FuGENE® 6 Transfection Reagent: minimizing reagent-dependent side effects as analyzed by gene- expression profiling and cytotoxicity assays Transfection protocols and the reagents used to deliver nucleic analysis and cell viability assays, we evaluated different transfection reagents to determine their effects

Cai, Long

70

Rapid separation of beryllium and lanthanide derivatives by capillary gas chromatography.  

PubMed

Previous studies describe derivatization of metal ions followed by analysis using gas chromatography, usually on packed columns. In many of these studies, stable and volatile derivatives were formed using fluorinated ?-diketonate reagents. This paper extends previous work by investigating separations of the derivatives on small-diameter capillary gas chromatography columns and exploring on-fiber, solid-phase microextraction derivatization techniques for beryllium. The ?-diketonate used for these studies was 1,1,1,2,2,6,6,7,7,7-decafluoro-3,5-heptanedione. Derivatization of lanthanides also required addition of a neutral donor, dibutyl sulfoxide, in addition to 1,1,1,2,2,6,6,7,7,7-decafluoro-3,5-heptanedione. Unoptimized separations on a 100-?m i.d. capillary column proved capable of rapid separations (within 15 min) of lanthanide derivatives that are adjacent to one another in the periodic table. Full-scan mass spectra were obtained from derivatives containing 5 ng of each lanthanide. Studies also developed a simple on-fiber solid-phase microextraction derivatization of beryllium. Beryllium could be analyzed in the presence of other alkali earth elements (Ba(II) and Sr(II)) without interference. Extension of the general approach was demonstrated for several additional elements (i.e. Cu(II), Cr(III), and Ga(III)). PMID:22945886

Harvey, Scott D; Lucke, Richard B; Douglas, Matt

2012-10-01

71

Rapid Separation of Beryllium and Lanthanide Derivatives by Capillary Gas Chromatography  

SciTech Connect

Previous studies describe derivatization of metal ions followed by analysis using gas chromatography, usually on packed columns. In many of these studies, stable and volatile derivatives were formed using fluorinated ?-diketonate reagents. This paper extends previous work by investigating separations of the derivatives on small-diameter capillary gas chromatography columns and exploring on-fiber, solid-phase microextraction derivatization techniques for beryllium. The ?-diketonate used for these studies was 1,1,1,2,2,6,6,7,7,7-decafluoro-3,5-heptanedione. Derivatization of lanthanides also required addition of a neutral donor, dibutyl sulfoxide, in addition to 1,1,1,2,2,6,6,7,7,7-decafluoro-3,5-heptanedione. Un-optimized separations on a 100-µm i.d. capillary column proved capable of rapid separations (within 15 min) of lanthanide derivatives that are adjacent to one another in the periodic table. Full-scan mass spectra were obtained from derivatives containing 5 ng of each lanthanide. Studies also developed a simple on-fiber solid-phase microextraction derivatization of beryllium. Beryllium could be analyzed in the presence of other alkali earth elements [Ba(II) and Sr(II)] without interference. Extension of the general approach was demonstrated for several additional elements [i.e., Cu(II), Cr(III), and Ga(III)].

Harvey, Scott D.; Lucke, Richard B.; Douglas, Matthew

2012-10-01

72

Lanthanide Complexes for Luminescence Imaging Applications  

Microsoft Academic Search

In this article, imaging applications of luminescent complexes and recent advances in the design and photophysical behaviour of near?IR responsive complexes are reviewed. Various properties of the luminescent lanthanide complexes are also discussed in detail.

Stephen Faulkner; Simon J. A. Pope

2005-01-01

73

Lanthanide-tagged proteins – An illuminating partnership  

E-print Network

Lanthanide-tagged proteins are valuable for exploiting the unique properties of Ln ions for investigating protein structure, function, and dynamics. Introduction of the Ln into the target is accomplished via chemical ...

Imperiali, Barbara

74

Review Article: The Effects of Radiation Chemistry on Solvent Extraction 3: A Review of Actinide and Lanthanide Extraction  

SciTech Connect

The partitioning of the long-lived ?-emitters and the high-yield fission products from dissolved nuclear fuel is a key component of processes envisioned for the safe recycling of nuclear fuel and the disposition of high-level waste. These future processes will likely be based on aqueous solvent extraction technologies for light water reactor fuel and consist of four main components for the sequential separation of uranium, fission products, group trivalent actinides and lanthanides, and then trivalent actinides from lanthanides. Since the solvent systems will be in contact with highly radioactive solutions, they must be robust toward radiolytic degradation in an irradiated mixed organic, aqueous acidic environment. Therefore, an understanding of their radiation chemistry is important to the design of a practical system. In the first paper in this series we reviewed the radiation chemistry of irradiated aqueous nitric acid and the tributyl phosphate ligand for uranium extraction in the first step of these extractions. In the second, we reviewed the radiation chemistry of the ligands proposed for use in the extraction of cesium and strontium fission products. Here, we review the radiation chemistry of the ligands that might be used in the third step in the series of separations, for the group extraction of the lanthanides and actinides. This includes traditional organophosphorous reagents such as CMPO and HDEHP, as well as novel reagents such as the amides and diamides currently being investigated.

Bruce J. Mincher; Giuseppe Modolo; Stephen P. Mezyk

2009-12-01

75

21 CFR 864.8540 - Red cell lysing reagent.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Red cell lysing reagent. 864.8540 Section 864... Hematology Reagents § 864.8540 Red cell lysing reagent. (a) Identification. A red cell lysing reagent is a device used to...

2010-04-01

76

21 CFR 866.3255 - Escherichia coli serological reagents.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Escherichia coli serological reagents. 866...Serological Reagents § 866.3255 Escherichia coli serological reagents. (a) Identification. Escherichia coli serological reagents...

2011-04-01

77

21 CFR 866.3255 - Escherichia coli serological reagents.  

...2014-04-01 2014-04-01 false Escherichia coli serological reagents. 866...Serological Reagents § 866.3255 Escherichia coli serological reagents. (a) Identification. Escherichia coli serological reagents...

2014-04-01

78

21 CFR 866.3255 - Escherichia coli serological reagents.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Escherichia coli serological reagents. 866...Serological Reagents § 866.3255 Escherichia coli serological reagents. (a) Identification. Escherichia coli serological reagents...

2012-04-01

79

21 CFR 866.3255 - Escherichia coli serological reagents.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Escherichia coli serological reagents. 866...Serological Reagents § 866.3255 Escherichia coli serological reagents. (a) Identification. Escherichia coli serological reagents...

2013-04-01

80

21 CFR 866.3375 - Mycoplasma spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Mycoplasma spp. serological reagents. 866...Serological Reagents § 866.3375 Mycoplasma spp. serological reagents. (a) Identification. Mycoplasma spp. serological reagents...

2010-04-01

81

21 CFR 866.3375 - Mycoplasma spp. serological reagents.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Mycoplasma spp. serological reagents. 866...Serological Reagents § 866.3375 Mycoplasma spp. serological reagents. (a) Identification. Mycoplasma spp. serological reagents...

2013-04-01

82

21 CFR 866.3375 - Mycoplasma spp. serological reagents.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Mycoplasma spp. serological reagents. 866...Serological Reagents § 866.3375 Mycoplasma spp. serological reagents. (a) Identification. Mycoplasma spp. serological reagents...

2011-04-01

83

21 CFR 866.3940 - West Nile virus serological reagents.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false West Nile virus serological reagents. 866.3940 ...Serological Reagents § 866.3940 West Nile virus serological reagents. (a) Identification. West Nile virus serological reagents are devices...

2011-04-01

84

21 CFR 866.3400 - Parainfluenza virus serological reagents.  

... 2014-04-01 false Parainfluenza virus serological reagents. 866.3400 Section...Reagents § 866.3400 Parainfluenza virus serological reagents. (a) Identification. Parainfluenza virus serological reagents are devices...

2014-04-01

85

21 CFR 866.3400 - Parainfluenza virus serological reagents.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false Parainfluenza virus serological reagents. 866.3400 Section...Reagents § 866.3400 Parainfluenza virus serological reagents. (a) Identification. Parainfluenza virus serological reagents are devices...

2013-04-01

86

21 CFR 866.3940 - West Nile virus serological reagents.  

...2014-04-01 2014-04-01 false West Nile virus serological reagents. 866.3940 ...Serological Reagents § 866.3940 West Nile virus serological reagents. (a) Identification. West Nile virus serological reagents are devices...

2014-04-01

87

21 CFR 866.3330 - Influenza virus serological reagents.  

...2014-04-01 2014-04-01 false Influenza virus serological reagents. 866.3330 ...Serological Reagents § 866.3330 Influenza virus serological reagents. (a) Identification. Influenza virus serological reagents are...

2014-04-01

88

Renewable-reagent electrochemical sensor  

DOEpatents

A new electrochemical probe(s) design allowing for continuous (renewable) reagent delivery. The probe comprises an integrated membrane-sampling/electrochemical sensor that prevents interferences from surface-active materials and greatly extends the linear range. The probe(s) is useful for remote or laboratory-based monitoring in connection with microdialysis sampling and electrochemical measurements of metals and organic compounds that are not readily detected in the absence of reacting with the compound. Also disclosed is a method of using the probe(s).

Wang, Joseph (Las Cruces, NM); Olsen, Khris B. (Richland, WA)

1999-01-01

89

The catalytic domain of MMP-1 studied through tagged lanthanides.  

PubMed

Pseudocontact shifts (pcs) and paramagnetic residual dipolar couplings (rdc) provide structural information that can be used to assess the adequacy of a crystallographic structure to represent the solution structure of a protein. This can be done by attaching a lanthanide binding tag to the protein. There are cases in which only local rearrangements are sufficient to match the NMR data and cases where significant secondary structure or domain rearrangements from the solid state to the solution state are needed. We show that the two cases are easily distinguishable. Whereas the use of solution restraints in the latter case is described in the literature, here we deal with how to obtain a better model of the solution structure in a case (the catalytic domain of the matrix metalloproteinase MMP-1) of the former class. PMID:21945315

Bertini, Ivano; Calderone, Vito; Cerofolini, Linda; Fragai, Marco; Geraldes, Carlos F G C; Hermann, Petr; Luchinat, Claudio; Parigi, Giacomo; Teixeira, João M C

2012-03-01

90

Polyborylated reagents for modern organic synthesis  

PubMed Central

Diverse kinds of gem- and vic-diborylated compounds are now readily available thanks to advances in gem-diborylation of lithium carbenoids as well as vic-diborylation of carbon–carbon multiple bonds with diboron compounds. These diborylated reagents lead to invention of polyborylated reagents and many novel and useful synthetic methods for supreme stereocontrol. This review summarizes preparative methods and synthetic reactions of di- and polyborylated reagents with the emphasis on multiple bond formation. PMID:18941288

SHIMIZU, Masaki; HIYAMA, Tamejiro

2008-01-01

91

In Vitro Selection of a New Lanthanide-Dependent DNAzyme for Ratiometric Sensing Lanthanides.  

PubMed

Developing biosensors for lanthanides is an important but challenging analytical task. To address this problem, in vitro selection of RNA-cleaving DNAzymes was carried out using a library containing a region of 35 random nucleotides in the presence of Lu(3+), since Lu(3+) was reported to be the most efficient lanthanide for RNA cleavage. The resulting DNA sequences can be aligned to a single family with two conserved stretches of nucleotides. One of the representative DNAzymes (named Lu12) was further studied. Lu12 is more active with smaller lanthanides and has the lowest activity in the presence of the largest lanthanide (lutetium). Its cleavage rate is 0.12 min(-1) in the presence of 10 ?M Nd(3+) at pH 6.0. This is a new DNAzyme, and a catalytic beacon sensor is designed by attaching a fluorophore/quencher pair, detecting Nd(3+) down to 0.4 nM (72 parts-per-trillion). This DNAzyme is highly selective for lanthanides as well, showing cleavage only with two nonlanthanide ions: Y(3+) and Pb(2+). We previously reported a DNAzyme named Ce13d, which has similar responses to all the trivalent lanthanides. Combining these two allows for a ratiometric assay that identifies a few large lanthanides. PMID:25199650

Huang, Po-Jung Jimmy; Vazin, Mahsa; Liu, Juewen

2014-10-01

92

The structure of the lanthanide aquo ions in solution as studied by 17O NMR spectroscopy and DFT calculations.  

PubMed

The (17)O NMR shifts of aqueous samples of lanthanide triflates were measured and analysed. In these systems the triflate anion does not enter the first coordination sphere. The contact contribution to the shifts showed a break at Eu(III), which reflects a change in the number of water molecules in the first coordination sphere of the Ln(III) ion from 9 for La-Sm to 8 for the heavier lanthanides. This change in hydration number is accompanied by a change in the parameters governing the pseudo-contact shifts. Fitting of the data with tricapped trigonal prism and square antiprismatic geometries obtained by DFT (density function theory) calculations showed that the crystal field parameters for these geometries differ by an order of magnitude. The hyperfine coupling constant for both geometries was determined to be A/(Planck's constant)= -4.2 x 10(6) rad s(-1). PMID:18217115

Djanashvili, Kristina; Platas-Iglesias, Carlos; Peters, Joop A

2008-02-01

93

Radiometallacarboranes as tumor imaging reagents  

SciTech Connect

Monoclonal antibodies (Mab), when conjugated with bifunctional chelation reagents containing a radiometal, have provided sensitive and accurate imaging agents for the detection of cancer and other diseases. The bifunctional chelates presently in use are generally of the aminocarboxylate family and subject to catabolism with release of metal ion in vivo. The authors have now designed, synthesized, and evaluated a functionalized cluster containing a radiotransition metal (venus flytrap cluster, VFC) which makes use of an inorganic ligand set, incorporates exceedingly strong cluster bonding based upon a bridged commo-bis(dicarbollide) structure, and can be prepared in the aqueous media commonly used to supply radiometal salts. The species reported here presages the existence of a large family of functionalized metallacarborane clusters which may serve as biologically inviolable radio-transition-metal carriers for the antibody-mediated {gamma}-imaging or {beta}-therapy of tumors.

Hawthorne, M.F.; Varadarajan, A.; Knobler, C.B.; Chakrabarti, S. (Univ. of California, Los Angeles (USA)); Paxton, R.J.; Beatty, B.G.; Curtis, F.L. (Beckman Research Institute of the City of Hope, Duarte, CA (USA))

1990-06-20

94

Sensing Lanthanide Metal Content in Biological Tissues with Magnetic Resonance Spectroscopy  

PubMed Central

The development and validation of MRI contrast agents consisting of a lanthanide chelate often requires a determination of the concentration of the agent in ex vivo tissue. We have developed a protocol that uses 70% nitric acid to completely digest tissue samples that contain Gd(III), Dy(III), Tm(III), Eu(III), or Yb(III) ions, or the MRI contrast agent gadodiamide. NMR spectroscopy of coaxial tubes containing a digested sample and a separate control solution of nitric acid was used to rapidly and easily measure the bulk magnetic susceptibility (BMS) shift caused by each lanthanide ion and gadodiamide. Each BMS shift was shown to be linearly correlated with the concentration of each lanthanide ion and gadodiamide in the 70% nitric acid solution and in digested rat kidney and liver tissues. These concentration measurements had outstanding precision, and also had good accuracy for concentrations ?10 mM for Tm(III) Eu(III), and Yb(III), and ?3 mM for Gd(III), gadodiamide, and Dy(III). Improved sample handling methods are needed to improve measurement accuracy for samples with lower concentrations. PMID:24152931

Hingorani, Dina V.; Gonzalez, Sandra I.; Li, Jessica F.; Pagel, Mark D.

2013-01-01

95

Curvature of the Lanthanide Contraction: An Explanation  

SciTech Connect

A number of studies have shown that for isostructural series of the lanthanides (elements La through Lu), a plot of equivalent metal-ligand bond lengths versus atomic number differs significantly from linearity and can be better fit as a quadratic equation. However, for hydrogen type wave functions, it is the inverse of the average distance of the electron from the nucleus (an estimate of size) that varies linearly with effective nuclear charge. This generates an apparent quadratic dependence of radius with atomic number. Plotting the inverse of lanthanide ion radii (the observed distance minus the ligand size) as a function of effective nuclear charge gives very good linear fits for a variety of lanthanide complexes and materials. Parameters obtained from this fit are in excellent agreement with the calculated Slater shielding constant, k.

Raymond, Kenneth; Wellman, Daniel; Sgarlata, Carmelo; Hill, Aru

2009-12-21

96

Separations of actinides, lanthanides and other metals  

DOEpatents

An organic extracting solution comprised of a bis(acylpyrazolone or a substituted bis(acylpyrazolone) and an extraction method useful for separating certain elements of the actinide series of the periodic table having a valence of four from one other, and also from one or more of the substances in a group consisting of hexavalent actinides, trivalent actinides, trivalent lanthanides, trivalent iron, trivalent aluminum, divalent metals, and monovalent metals and also from one or more of the substances in a group consisting of hexavalent actinides, trivalent actinides, trivalent lanthanides, trivalent iron, trivalent aluminum, divalent metals, and monovalent metals and also useful for separating hexavalent actinides from one or more of the substances in a group consisting of trivalent actinides, trivalent lanthanides, trivalent iron, trivalent aluminum, divalent metals, and monovalent metals.

Smith, Barbara F. (Los Alamos, NM); Jarvinen, Gordon D. (Los Alamos, NM); Ensor, Dale D. (Cookeville, TN)

1995-01-01

97

Separation of lanthanides from trivalent actinides, the role of aqueous-phase soft-donor complexing agents  

SciTech Connect

Closing the nuclear fuel cycle to reduce storage volumes and times requires advanced separation processes, among which is the separation of trivalent actinides from lanthanides that are present in the waste. A proven system is TALSPEAK, utilizing polyamino-carboxylates for this group separation. However, the narrow pH range these molecules require complicates their use. Soft-donor molecules that may complex actinides at low pH have been investigated. Results indicate that, although DTPA gives the best selectivity, all molecules tested showed preference for americium. The solubility of some reagents at low pH suggests the need for further development. (authors)

Nilsson, Mikael; Hoch, Cortney; Meier, G. Patrick; Nash, Kenneth L. [Chemistry Department, Washington State University, P.O. Box 644630, Pullman, WA (United States)

2008-07-01

98

A thermal study of several lanthanide triflates  

Microsoft Academic Search

Five lanthanide triflates, Ln(TfO)3·nH2O, where TfO?=CF3SO3?, Ln=La3, Nd3, Sm3, Gd3 and Yb3, and n=9 and 13, have been prepared and the thermal decomposition processes of these triflates up to 600°C were characterized by means of TG, DTA, XRD. The thermal studies have shown almost all the lanthanide triflates prepared in this study to exist as a stable nonahydrate. During the

Naohisa Yanagihara; Shin Nakamura; Masayoshi Nakayama

1998-01-01

99

Enantioselective organocatalytic epoxidation using hypervalent iodine reagents  

E-print Network

Enantioselective organocatalytic epoxidation using hypervalent iodine reagents Sandra Lee and David Abstract--A rare example of a hypervalent iodine reagent participating in a 1,4-heteroconjugate addition imidazolidinone catalyst 1. Development of an `internal syringe pump' effect via the slow release of iodosobenzene

MacMillan, David W. C.

100

Scalar Static Polarizabilities of Lanthanides and Actinides  

E-print Network

We calculate scalar static polarizabilities for lanthanides and actinides, the atoms with open $4f$ or $5f$ subshell. We show that polarizabilities of the low states are approximately the same for all states of given configuration and present a way of calculating them reducing valence space to just two or three valence electrons occupying $6s$ and $5d$ states for lanthanides or $7s$ and $6d$ states for actinides while $4f$ and $5f$ states are considered to be in the core. Configuration interaction technique is used to calculate polarizabilities of lanthanides and actinides for all states of the $4f^n6s^2$ and $4f^{n-1}6s^25d$ configurations of lanthanides and all states of the $5f^{n}7s^2$ and $5f^{n-1}7s^26d$ configurations of actinides. Polarizability of the electron core (including f-orbitals) has been calculated in the RPA approximation.

Dzuba, V A; Flambaum, V V

2014-01-01

101

Pyridinophane platform for stable lanthanide(III) complexation.  

PubMed

A detailed investigation of the solid state and solution structures of lanthanide(III) complexes with the macrocyclic ligand 2,11,20-triaza[3.3.3](2,6)pyridinophane (TPP) is reported. The solid state structures of 14 different Ln(3+) complexes have been determined using X-ray crystallography. The ligand is coordinating to the Ln(3+) ion by using its six nitrogen atoms, while nitrate or triflate anions and water molecules complete the metal coordination environments. The structure of the complexes in solution has been investigated by (1)H and (13)C NMR spectroscopy, as well as by DFT calculations (TPSSh model) performed in aqueous solution. The structures obtained from these calculations for the complexes with the lightest Ln(3+) ions (La-Sm) are in very good agreement with those determined by the analysis of the Ln(3+)-induced paramagnetic shifts. A structural change occurs across the lanthanide series at Sm(3+); the complexes of the large Ln(3+) ions (La-Nd) are chiral due to the nonplanar conformation of the macrocycle, and present effective C3v symmetries in solution as a consequence of a fast interconversion of two enantiomeric forms with C3 symmetry. The activation free energy for this enantiomerization process, as estimated by using DFT calculations, amounts to 33.0 kJ·mol(-1). The TPP ligand in the complexes of the heaviest Ln(3+) ions (Eu-Lu) presents a half-chair conformation, which results in C(s) symmetries in solution. PMID:23627284

Castro, Goretti; Bastida, Rufina; Macías, Alejandro; Pérez-Lourido, Paulo; Platas-Iglesias, Carlos; Valencia, Laura

2013-05-20

102

21 CFR 660.20 - Blood Grouping Reagent.  

Code of Federal Regulations, 2010 CFR

... 7 2010-04-01 2010-04-01 false Blood Grouping Reagent. 660.20 Section 660...FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Blood Grouping Reagent § 660.20 Blood Grouping Reagent. (a) Proper name and...

2010-04-01

103

21 CFR 864.8100 - Bothrops atrox reagent.  

Code of Federal Regulations, 2011 CFR

...Reagents § 864.8100 Bothrops atrox reagent. (a) Identification. A Bothrops atrox reagent is a device made from snake venom and used to determine blood fibrinogen levels to aid in the evaluation of disseminated intravascular...

2011-04-01

104

21 CFR 866.3520 - Rubeola (measles) virus serological reagents.  

...2014-04-01 false Rubeola (measles) virus serological reagents. 866.3520... § 866.3520 Rubeola (measles) virus serological reagents. (a) Identification. Rubeola (measles) virus serological reagents are devices...

2014-04-01

105

21 CFR 866.3520 - Rubeola (measles) virus serological reagents.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Rubeola (measles) virus serological reagents. 866.3520... § 866.3520 Rubeola (measles) virus serological reagents. (a) Identification. Rubeola (measles) virus serological reagents are devices...

2013-04-01

106

21 CFR 866.3520 - Rubeola (measles) virus serological reagents.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Rubeola (measles) virus serological reagents. 866.3520... § 866.3520 Rubeola (measles) virus serological reagents. (a) Identification. Rubeola (measles) virus serological reagents are devices...

2011-04-01

107

Stick shift  

E-print Network

Stick Shift is a novel that has undergone several rounds of significant revision. Scott, the book's main character, is a sarcastic American who travels to England to move in with an ex-girlfriend. He experiences all of the ...

Parness, Aaron J. (Aaron Joseph), 1981-

2004-01-01

108

Extraction separation of tervalent americium and lanthanides in the presence of some soft and hard donors and dicarbollide  

SciTech Connect

Some combinations of extractants involving dicarbollide as one component for the separation of Am/Ln were studied. Extraction by TOPO is not influenced to a great extent by the presence of dicarbollide, and TPTZ in the presence of dicarbollide is ineffective for the extraction from 0.1 M HNO[sub 3]. General aspects of the selectivity of lanthanides and of Am/Ln separation in the presence of various reagents are discussed with emphasis on the difficulties of the separation of Am from light lanthanides. A new extraction procedure by dicarbollide in the presence of an excess of o-phenanthroline over the mineral acid is proposed. This led to the highest separation factors D[sub Am]/D[sub Eu] (20-34) from 0.1 M HNO[sub 3]. The behavior of other lanthanides is similar to that of Eu, with a maximum distribution ratio for Nd (D[sub Nd]/D[sub Eu] = 2). 27 refs., 10 figs.

Rais, J.; Tachimori, S. (Japan Atomic Emergy Research Institute, Ibaraki (Japan))

1994-06-01

109

Manufacturability of lab on chip devices : reagent-filled reservoirs bonding process and its effect on reagents flow pattern  

E-print Network

In its lab-on-a-chip product, Daktari Diagnostics utilizes "reagent-filled reservoirs" as a means of storing and delivering the liquid reagent. During the clinical trials of the product, undesired reagent flow patterns ...

Saber, Aabed (Aabed Saud)

2013-01-01

110

21 CFR 866.3370 - Mycobacterium tuberculosis immunofluorescent reagents.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Mycobacterium tuberculosis immunofluorescent reagents... § 866.3370 Mycobacterium tuberculosis immunofluorescent reagents...Identification. Mycobacterium tuberculosis immunofluorescent...

2011-04-01

111

21 CFR 866.3370 - Mycobacterium tuberculosis immunofluorescent reagents.  

...2014-04-01 false Mycobacterium tuberculosis immunofluorescent reagents... § 866.3370 Mycobacterium tuberculosis immunofluorescent reagents...Identification. Mycobacterium tuberculosis immunofluorescent...

2014-04-01

112

21 CFR 864.4020 - Analyte specific reagents.  

Code of Federal Regulations, 2010 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Specimen Preparation Reagents § 864.4020 Analyte specific reagents. (a) Identification....

2010-04-01

113

21 CFR 864.4020 - Analyte specific reagents.  

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Specimen Preparation Reagents § 864.4020 Analyte specific reagents. (a) Identification....

2014-04-01

114

Microwave assisted reactions using polyvinylpyrrolidone supported reagents;.  

E-print Network

??Polyvinylpyrrolidone-bromine complex was synthesized and used as a versatile and efficient polymeric reagent for the oxidation of alcohols, dihalogenation of unsaturated compounds, and#61537;-halogenation of ketones,… (more)

Sebastian, Saju M

2014-01-01

115

Intracellular internalization mechanism of protein transfection reagents.  

PubMed

A protein transfection reagent is a powerful tool for elucidating a protein function in a cell, and plays an important role in the fields of cell biology and drug discovery. Many researchers have developed protein delivery systems and several systems are commercially available. In this study, we focus on the biological functions of three commercially available protein transfection reagents, Pro-DeliverIN, Xfect, and TurboFect, especially in their internalization routes by HeLa cells. A cellular uptake study using specific endocytosis inhibitors and confocal laser scanning microscope observation revealed that each reagent was internalized into HeLa cells by different mechanism. It is our hope that the results presented here will help in the choice and use of protein transfection reagents for experiments. PMID:22791153

Oba, Makoto; Tanaka, Masakazu

2012-01-01

116

Catalytic enantioselective conjugate addition with Grignard reagents.  

PubMed

In this Account, recent advances in catalytic asymmetric conjugate addition of Grignard reagents are discussed. Synthetic methodology to perform highly enantioselective Cu-catalyzed conjugate addition of Grignard reagents to cyclic enones with ee's up to 96% was reported in 2004 from our laboratories. Excellent levels of stereocontrol were achieved with Cu(I) halides, alkylmagnesium bromides, and commercially available chiral ferrocenyl diphosphines. Studies carried out during the last 2 years demonstrated that these Cu-catalysts are very effective for the enantioselective conjugate addition of Grignard reagents to acyclic enones, alpha,beta-unsaturated esters, and thioesters. On the basis of this methodology, a diastereo- and enantioselective iterative route to deoxypropionate units was developed and applied to the synthesis of natural products. Finally, we summarize our recently conducted mechanistic investigations and the application of this catalytic system to the enantioselective SN2' substitution reactions of allylic bromides with Grignard reagents. PMID:17370989

López, Fernando; Minnaard, Adriaan J; Feringa, Ben L

2007-03-01

117

Lanthanide-cyclodextrin complexes as probes for elucidating optical purity by NMR spectroscopy  

SciTech Connect

A multidentate ligand is bonded to cyclodextrins by the reaction of diethylenetriaminepentaacetic dianhydride with 6-mono- and 2-mono(ethylenediamine) derivatives of cyclodextrin. Adding Dy(III) to the cyclodextrin derivatives enhances the enantiomeric resolution in the [sup 1]H NMR spectra of carbionoxamine maleate, doxylamine succinate, pheniramine maleate, propranolol hydrochloride, and tryptophan. The enhancement is more pronounced with the secondary derivative. The Dy(III)-induced shifts can be used to elucidate the geometry of cyclodextrin-substrate inclusion complexes. Lanthanide-induced shifts are reported for complexes of aspartame, tryptophan, propranolol, and 1-anilino-8-naphthalenesulfonate with cyclodextrins, and the relative magnitudes of the shifts agree with previously reported structures of the complexes. 37 refs., 9 figs., 5 tabs.

Wenzel, T.J.; Bogyo, M.S.; Lebeau, E.L. (Bates College, Lewiston, ME (United States))

1994-06-01

118

Actinide and lanthanide separation process (ALSEP)  

DOEpatents

The process of the invention is the separation of minor actinides from lanthanides in a fluid mixture comprising, fission products, lanthanides, minor actinides, rare earth elements, nitric acid and water by addition of an organic chelating aid to the fluid; extracting the fluid with a solvent comprising a first extractant, a second extractant and an organic diluent to form an organic extractant stream and an aqueous raffinate. Scrubbing the organic stream with a dicarboxylic acid and a chelating agent to form a scrubber discharge. The scrubber discharge is stripped with a simple buffering agent and a second chelating agent in the pH range of 2.5 to 6.1 to produce actinide and lanthanide streams and spent organic diluents. The first extractant is selected from bis(2-ethylhexyl)hydrogen phosphate (HDEHP) and mono(2-ethylhexyl)2-ethylhexyl phosphonate (HEH(EHP)) and the second extractant is selected from N,N,N,N-tetra-2-ethylhexyl diglycol amide (TEHDGA) and N,N,N',N'-tetraoctyl-3-oxapentanediamide (TODGA).

Guelis, Artem V.

2013-01-15

119

Unnatural Isotopic Composition of Lithium Reagents  

USGS Publications Warehouse

Isotopic analysis of 39 lithium reagents from several manufacturers indicates that seven were artificially depleted in 6Li significantly in excess of the variation found in terrestrial materials. The atomic weight of lithium in analyzed reagents ranged from 6.939 to 6.996, and ??7-Li, reported relative to L-SVEC lithium carbonate, ranged from -11 to +3013???. This investigation indicates that 6Li-depleted reagents are now found on chemists' shelves, and the labels of these 6Li-depleted reagents do not accurately reflect the atomic and (or) molecular weights of these reagents. In 1993, IUPAC issued the following statement: "Commercially available Li materials have atomic weights that range between 6.94 and 6.99; if a more accurate value is required, it must be determined for the specific material." This statement has been found to be incorrect In two of the 39 samples analyzed, the atomic weight of Li was in excess of 6.99.

Qi, H.P.; Coplen, T.B.; Wang, Q. Zh; Wang, Y.-H.

1997-01-01

120

Matrix infrared spectroscopic and computational investigations of the lanthanide-methylene complexes CH2LnF2 with single Ln-C bonds.  

PubMed

Laser-ablated lanthanide metal atoms were condensed with CH(2)F(2) in excess argon at 6 K or neon at 4 K. New infrared absorption bands are assigned to the oxidative addition product methylene lanthanide difluorides on the basis of deuterium substitution and vibrational frequency calculations with density functional theory (DFT). Two dominant absorptions in the 500 cm(-1) region are identified as lanthanide-fluoride stretching modes for this very strong infrared absorption. The predominantly lanthanide-carbon stretching modes follow a similar trend of increasing with metal size and have characteristic 30 cm(-1) deuterium and 14 cm(-1) (13)C isotopic shifts. The electronic structure calculations show that these CH(2)LnF(2) complexes are not analogous to the simple transition and actinide metal methylidenes with metal-carbon double bonds that have been investigated previously, because the lanthanide metals (in the +2 or +3 oxidation state) do not appear to form a ?-type bond with the CH(2) group. The DFT and ab initio correlated molecular orbital theory calculations predict that these complexes exist as multiradicals, with a Ln-C ? bond and a single electron on C-2p weakly coupled with f(x) (x = 1 (Ce), 2 (Pr), 3(Nd), etc.) electrons in the adjacent Ln-4f orbitals. The Ln-C ? bond is composed of about 15% Ln-5d,6s and 85% C-sp(2) hybrid orbital. The Ln orbital has predominantly 6s and 5d character with more d-character for early lanthanides and increasing amounts of s-character across the row. The Ln-F bonds are almost purely ionic. Accordingly, the argon-neon matrix shifts are large (13-16 cm(-1)) for the ionic Ln-F bond stretching modes and small (?1 cm(-1)) for the more covalent Ln-C bond stretching modes. PMID:21332181

Wang, Xuefeng; Cho, Han-Gook; Andrews, Lester; Chen, Mingyang; Dixon, David A; Hu, Han-Shi; Li, Jun

2011-03-17

121

Lanthanide(III) nosylates as new nitration catalysts  

Microsoft Academic Search

Lanthanide(III) nosylates are novel, recyclable catalysts prepared from the noncorrosive and inexpensive p-nitrotoluenesulfonic acid and the corresponding lanthanide(III) oxide. With 5–10% catalyst loading, atom economic nitration of simple aromatic compounds was achieved in good to high yields.

Tatjana N. Parac-Vogt; Koen Binnemans

2004-01-01

122

Regioselective green anomeric deacetylation catalyzed by lanthanide triflates  

Microsoft Academic Search

Lanthanide triflates, especially Nd(OTf)3, efficiently catalyze the regioselective transesterification of anomeric acetates. This method offers an efficient solution for the otherwise difficult removal of methyl uronates anomeric acetates as well as a green alternative to published protocols since the lanthanide catalysts are non-toxic and may be easily recycled and reused.

Anh Tuan Tran; Sophie Deydier; David Bonnaffé; Christine Le Narvor

2008-01-01

123

One-dimensional simulation of lanthanide isotachophoresis using COMSOL.  

PubMed

Electrokinetic separations can be used to quickly separate rare earth metals to determine their forensic signature. In this work, we simulate the concentration and separation of trivalent lanthanide cations by isotachophoresis. A one-dimensional simulation is developed using COMSOL v4.0a, a commercial finite element simulator, to represent the isotachophoretic separation of three lanthanides: lanthanum, terbium, and lutetium. The binding ligand chosen for complexation with the lanthanides is ?-hydroxyisobutyric acid (HIBA) and the buffer system includes acetate, which also complexes with the lanthanides. The complexes formed between the three lanthanides, HIBA, and acetate are all considered in the simulation. We observe that the presence of only lanthanide:HIBA complexes in a buffer system with 10 mM HIBA causes the slowest lanthanide peak (lutetium) to split from the other analytes. The addition of lanthanide:acetate complexes into the simulation of the same buffer system eliminates this splitting. Decreasing the concentration of HIBA in the buffer to 7 mM causes the analyte stack to migrate faster through the capillary. PMID:22522543

Dixon, Derek R; Clark, Sue B; Ivory, Cornelius F

2012-03-01

124

Separation of tervalent lanthanides from actinides by extraction chromatography  

Microsoft Academic Search

A procedure is described for the removal of milligram amounts of lanthanides from the tervalent actinides. The routine application of an earlier procedure resulted in low americium yields and poor resolution of the ) spectrum, mainly due to inadequate removal of neodymium. The reported procedure offers many significant improvements and involves prepurification of the lanthanide-actinide fraction by precipitation as a

Don B. Martin; Dennis G. Pope

1982-01-01

125

Phthalamide lanthanide complexes for use as luminescent markers  

DOEpatents

The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one phthalamidyl moiety. Also provided are probes incorporating the phthalamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

Raymond, Kenneth N. (Berkeley, CA); Petoud, Stephane (Berkeley, CA); Cohen, Seth M. (Boston, MA); Xu, Jide (Berkeley, CA)

2003-01-01

126

Salicylamide-lanthanide complexes for use as luminescent markers  

DOEpatents

The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one salicylamidyl moiety. Also provided are probes incorporating the salicylamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

Raymond, Kenneth N. (Berkeley, CA); Petoud, Stephane (Berkeley, CA); Cohen, Seth (West Lake Village, CA); Xu, Jide (Berkeley, CA)

2002-01-01

127

Separation of trivalent lanthanides and actinides by solvent extraction without aqueous complexing agents  

Microsoft Academic Search

A method of separating the trivalent actinides, mainly Am and Cm, from ; trivalent lanthanides is presented. This method embodies the sequential use of ; two different solvent extractants; the first extractant would remove the heavy ; lanthanides from the lighter lanthanides and Am--Cm, while the second would ; extract Am--Cm in preference to the lighter lanthanides. In this scheme,

G. B. Kasting; J. A. Heppert; E. K. Hulet; J. F. Wild

1976-01-01

128

Fluid Shifts  

NASA Technical Reports Server (NTRS)

NASA is focusing on long-duration missions on the International Space Station (ISS) and future exploration-class missions beyond low Earth orbit. Visual acuity changes observed after short-duration missions were largely transient, but more than 30% of ISS astronauts experience more profound, chronic changes with objective structural and functional findings such as papilledema and choroidal folds. Globe flattening, optic nerve sheath dilation, and optic nerve tortuosity also are apparent. This pattern is referred to as the visual impairment and intracranial pressure (VIIP) syndrome. VIIP signs and symptoms, as well as postflight lumbar puncture data, suggest that elevated intracranial pressure (ICP) may be associated with the space flight-induced cephalad fluid shifts, but this hypothesis has not been tested. The purpose of this study is to characterize fluid distribution and compartmentalization associated with long-duration space flight, and to correlate these findings with vision changes and other elements of the VIIP syndrome. We also seek to determine whether the magnitude of fluid shifts during space flight, as well as the VIIP-related effects of those shifts, is predicted by the crewmember's pre-flight condition and responses to acute hemodynamic manipulations (such as head-down tilt). Lastly, we will evaluate the patterns of fluid distribution in ISS astronauts during acute reversal of fluid shifts through application of lower body negative pressure (LBNP) interventions to characterize and explain general and individual responses. We will examine a variety of physiologic variables in 10 long-duration ISS crewmembers using the test conditions and timeline presented in the Figure below. Measures include: (1) fluid compartmentalization (total body water by D2O, extracellular fluid by NaBr, intracellular fluid by calculation, plasma volume by CO rebreathe, interstitial fluid by calculation); (2) forehead/eyelids, tibia, calcaneus tissue thickness (by ultrasound); (3) vascular dimensions by ultrasound (jugular veins, cerebral and carotid arteries, vertebral arteries and veins, portal vein); (4) vascular dynamics by MRI (head/neck blood flow, cerebrospinal fluid pulsatility); (5) ocular measures (optical coherence tomography, intraocular pressure, 2-dimensional ultrasound including optic nerve sheath diameter, globe flattening, and retina-choroid thickness, Doppler ultrasound of ophthalmic and retinal arteries, and veins); (6) cardiac variables by ultrasound (inferior vena cava, tricuspid flow and tissue Doppler, pulmonic valve, stroke volume, right heart dimensions and function, four-chamber views); and (7) ICP measures (tympanic membrane displacement, distortion-product otoacoustic emissions, and ICP calculated by MRI). On the ground, acute head-down tilt will induce cephalad fluid shifts, whereas LBNP will oppose these shifts. Controlled Mueller maneuvers will manipulate cardiovascular variables. Through interventions applied before, during, and after flight, we intend to fully evaluate the relationship between fluid shifts and the VIIP syndrome. This study has been selected for flight implementation and is one of the candidate investigations being considered for the one year mission.

Stenger, Michael; Hargens, A.; Dulchavsky, S.; Ebert, D.; Lee, S.; Sargsyan, A.; Martin, D.; Lui, J.; Macias, B.; Arbeille, P.; Platts, S.

2014-01-01

129

Cytophotometric studies of schiff-type reagents  

E-print Network

was twenty minut es, The dye reagents used. Co stain Che tissues were paxarosaniline S02 (0 ~ Xa 42500) ~ phenosafranin~S02 (0 ~ X ~ 50200) ~ safrenin 0 802 (0 ~ X ~ 50240) ~ rhodamine 5~02 (O, X, 45210) ~ Bismarck brown Y-802 (O. X, 21000...)~ acrlflavtne-802 (46000), oresyl violet-SO? and. neutral violet-802 (C, X+50030) ~ 411 dye solutions had a dye concentration oi' 0 5/o~ aud were saturated with SQ2 to allow specific staining of aldebydeso Aldehyde specificity of these reagents was verified...

Aviles-Rios, Norman D

2012-06-07

130

Lanthanide Chelates as Bilayer Alignment Tools in NMR Studies of Membrane-Associated Peptides  

NASA Astrophysics Data System (ADS)

Theequimolar complex, consisting of the lipid-like, amphiphilic chelating agent 1,11-bis[distearylamino]-diethylenetriamine pentaacetic acid (DTPA-18) and Tm 3+, is shown by deuterium ( 2H) NMR to be useful in aligning bicelle-like model membranes, consisting of dimyristoylphosphatidylcholine (DMPC) and dihexanoylphosphatidylcholine (DHPC). As shown previously (1996, R. S. Prosser et al., J. Am. Chem. Soc. 118, 269-270), in the absence of chelate, the lanthanide ions bind loosely with the lipid phosphate groups and confer the membrane with a sufficient positive magnetic anisotropy to result in parallel alignment (i.e., average bilayer normal along the field). Apparently, DTPA-18 sequesters the lanthanide ions and inserts into the phospholipid bilayer in such a manner that bilayer morphology is preserved over a wide temperature range (35-70°C). The inherent paramagnetic shifts and line broadening effects are illustrated by 2H NMR spectra of the membrane binding peptide, Leu-enkephalin (Lenk- d2, Tyr-(Gly- d2)-Gly-Phe-Leu-OH), in the presence of varying concentrations of Tm 3+, and upon addition of DTPA-18. Two conclusions could be drawn from this study: (1) The addition of Tm 3+ to the bicelle system is consistent with a conformational change in the surface associated peptide, and this effect is shown to be reversed by addition of the chelate, and (2) The paramagnetic shifts are shown to be significantly reduced by addition of chelate.

Prosser, R. S.; Bryant, H.; Bryant, R. G.; Vold, Regitze R.

1999-12-01

131

Supplemental Materials and Methods Proteins and reagents  

E-print Network

with [-32 P]dATP using the Klenow fragment of DNA polymerase. After drying, the 1D and 2D gels were manuallySupplemental Materials and Methods Proteins and reagents Proteins were purified as described previously: RecA, RecQ, and SSB proteins (Harmon and Kowalczykowski 1998); RecF protein (Morimatsu

Kowalczykowski, Stephen C.

132

Determination of Cellular Cholesterol Content Reagents Needed  

E-print Network

Determination of Cellular Cholesterol Content Reagents Needed: Wako CII Cholesterol CII assay kit solvents using the SpeedVac. 4. Add 1 ml of the Cholesterol CII (Wako) buffer solution and vortex development with cholesterol is stable for incubation periods of up to 60 min. at 37° C. If detecting ent-cholesterol

Pike, Linda J.

133

DEGRADATION OF MTBE INTERMEDIATES USING FENTON'S REAGENT  

EPA Science Inventory

In a previous study, the chemical oxidation of MTBE at low concentrations in water using the Fenton's reagent (FR) was investigated. At certain reaction conditions the process achieved 99.99% degradation of MTBE but it did not result in complete MTBE mineralization. In the pres...

134

Reactions of difluorocarbene with organozinc reagents.  

PubMed

Reactions of difluorocarbene with benzyl and alkylzinc halides leading to fluorinated organozinc species have been described. The generated ?-difluorinated organozinc reagents are reasonably stable in solution and can be quenched with external electrophiles (iodine, bromine, proton), affording compounds containing the CF(2) fragment. PMID:23368906

Levin, Vitalij V; Zemtsov, Artem A; Struchkova, Marina I; Dilman, Alexander D

2013-02-15

135

Understanding stability trends along the lanthanide series.  

PubMed

The stability trends across the lanthanide series of complexes with the polyaminocarboxylate ligands TETA(4-) (H4TETA=2,2',2'',2'''-(1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetrayl)tetraacetic acid), BCAED(4-) (H4BCAED=2,2',2'',2'''-{[(1,4-diazepane-1,4-diyl)bis(ethane-2,1-diyl)]bis(azanetriyl)}tetraacetic acid), and BP18C6(2-) (H2BP18C6=6,6'-[(1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyl)bis(methylene)]dipicolinic acid) were investigated using DFT calculations. Geometry optimizations performed at the TPSSh/6-31G(d,p) level, and using a 46+4f(n) ECP for lanthanides, provide bond lengths of the metal coordination environments in good agreement with the experimental values observed in the X-ray structures. The contractions of the Ln(3+) coordination spheres follow quadratic trends, as observed previously for different isostructural series of complexes. We show here that the parameters obtained from the quantitative analysis of these data can be used to rationalize the observed stability trends across the 4f period. The stability trends along the lanthanide series were also evaluated by calculating the free energy for the reaction [La(L)](n+/-)(sol)+Ln(3+)(sol)?[Ln(L)](n+/-)(sol)+La(3+)(sol). A parameterization of the Ln(3+) radii was performed by minimizing the differences between experimental and calculated standard hydration free energies. The calculated stability trends are in good agreement with the experimental stability constants, which increase markedly across the series for BCAED(4-) complexes, increase smoothly for the TETA(4-) analogues, and decrease in the case of BP18C6(2-) complexes. The resulting stability trend is the result of a subtle balance between the increased binding energies of the ligand across the lanthanide series, which contribute to an increasing complex stability, and the increase in the absolute values of hydration energies along the 4f period. PMID:24577810

Regueiro-Figueroa, Martín; Esteban-Gómez, David; de Blas, Andrés; Rodríguez-Blas, Teresa; Platas-Iglesias, Carlos

2014-04-01

136

Compositional variations in monomeric trimethylsilylated allyl lanthanide complexes  

Microsoft Academic Search

Treatment of three equivalents of the potassium salt of the bis(1,3-trimethylsilyl)allyl anion with various late lanthanide triflates (M=Dy, Ho, Er, Tm, Lu) produces the unsolvated triallyllanthanide complexes LnA3? (A?=1,3-(SiMe3)2C3H3). The use of lanthanide halides (Cl, I) with the potassium allyl also generates neutral complexes, but when lanthanide iodides and the corresponding lithium allyl are combined, the lanthanate species Li(thf)4[LnA3?I] are

Rosemary E. White; Timothy P. Hanusa; Benjamin E. Kucera

2007-01-01

137

Calibration beads containing luminescent lanthanide ion complexes.  

PubMed

The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, would be enhanced by the availability of narrowband emitting, UV excited lanthanide calibration beads. 0.5-, 3-, and 5-microm beads containing a luminescent europium-complex are manufactured. The luminescence distribution of the 5-microm beads is measured with a time-delayed light-scatter-gated luminescence flow cytometer to have a 7.0% coefficient of variation (CV) The spacial distribution of the europium-complex in individual beads is determined to be homogeneous by confocal microscopy. Emission peaks are found at 592, 616 (width 9.9 nm), and 685 nm with a PARISS spectrophotometer. The kinetics of the luminescence bleaching caused by UV irradiation of the 0.5- and 5-microm beads measured under LED excitation with a fluorescence microscope indicate that bleaching does not interfere with their imaging. The luminescence lifetimes in water and air were 340 and 460 micros, respectively. Thus, these 5-microm beads can be used for spectral calibration of microscopes equipped with a spectrograph, as test particles for time-delayed luminescence flow cytometers, and possibly as labels for macromolecules and cells. PMID:19405752

Leif, Robert C; Yang, Sean; Jin, Dayong; Piper, James; Vallarino, Lidia M; Williams, John W; Zucker, Robert M

2009-01-01

138

Calibration beads containing luminescent lanthanide ion complexes  

NASA Astrophysics Data System (ADS)

The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, would be enhanced by the availability of narrowband emitting, UV excited lanthanide calibration beads. 0.5-, 3-, and 5-?m beads containing a luminescent europium-complex are manufactured. The luminescence distribution of the 5-?m beads is measured with a time-delayed light-scatter-gated luminescence flow cytometer to have a 7.0% coefficient of variation (CV) The spacial distribution of the europium-complex in individual beads is determined to be homogeneous by confocal microscopy. Emission peaks are found at 592, 616 (width 9.9 nm), and 685 nm with a PARISS® spectrophotometer. The kinetics of the luminescence bleaching caused by UV irradiation of the 0.5- and 5-?m beads measured under LED excitation with a fluorescence microscope indicate that bleaching does not interfere with their imaging. The luminescence lifetimes in water and air were 340 and 460 ?s, respectively. Thus, these 5-?m beads can be used for spectral calibration of microscopes equipped with a spectrograph, as test particles for time-delayed luminescence flow cytometers, and possibly as labels for macromolecules and cells.

Leif, Robert C.; Yang, Sean; Jin, Dayong; Piper, James; Vallarino, Lidia M.; Williams, John W.; Zucker, Robert M.

2009-03-01

139

21 CFR 866.3660 - Shigella spp. serological reagents.  

Code of Federal Regulations, 2011 CFR

...Shigella spp. serological reagents are devices that consist of antigens and antisera, including antisera conjugated with a fluorescent dye (immunofluorescent reagents), used in serological tests to identify Shigella spp. from cultured isolates....

2011-04-01

140

21 CFR 866.3460 - Rabiesvirus immuno-fluorescent reagents.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Rabiesvirus immuno-fluorescent reagents. 866.3460 Section 866... § 866.3460 Rabiesvirus immuno-fluorescent reagents. (a) Identification...rabiesvirus antisera conjugated with a fluorescent dye used to identify...

2011-04-01

141

21 CFR 866.3085 - Brucella spp. serological reagents.  

Code of Federal Regulations, 2011 CFR

...identify antibodies to Brucella spp. in serum. Additionally, some of these reagents consist of antisera conjugated with a fluorescent dye (immunofluorescent reagents) used to identify Brucella spp. directly from clinical specimens or cultured...

2011-04-01

142

21 CFR 866.3460 - Rabiesvirus immuno-fluorescent reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Rabiesvirus immuno-fluorescent reagents. 866.3460 Section 866... § 866.3460 Rabiesvirus immuno-fluorescent reagents. (a) Identification...rabiesvirus antisera conjugated with a fluorescent dye used to identify...

2010-04-01

143

21 CFR 866.3660 - Shigella spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...Shigella spp. serological reagents are devices that consist of antigens and antisera, including antisera conjugated with a fluorescent dye (immunofluorescent reagents), used in serological tests to identify Shigella spp. from cultured isolates....

2010-04-01

144

The Grignard Reagent: Preparation, Structure, and Some Reactions.  

ERIC Educational Resources Information Center

The Grignard reagent used in the laboratory synthesis of organic compounds is the product resulting from the reaction of an alkyl or aryl halide with elemental magnesium. Describes the structure, formation, and some reactions of the reagent. (YP)

Orchin, Milton

1989-01-01

145

21 CFR 866.3110 - Campylobacter fetus serological reagents.  

Code of Federal Regulations, 2013 CFR

... false Campylobacter fetus serological reagents...DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED...3110 Campylobacter fetus serological reagents...diseases. Campylobacter fetus is a frequent cause...of the intestines) in humans. (b)...

2013-04-01

146

21 CFR 866.3355 - Listeria spp. serological reagents.  

Code of Federal Regulations, 2013 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3355 Listeria spp. serological reagents. (a)...

2013-04-01

147

CLAY AND CLAY-SUPPORTED REAGENTS IN ORGANIC SYNTHESES  

EPA Science Inventory

CLAY AND CLAY-SUPPORTED REAGENTS HAVE BEEN USED EXTENSIVELY FOR SYNTHETIC ORGANIC TRANSFORMATIONS. THIS OVERVIEW DESCRIBES THE SALIENT STRUCTURAL PROPERTIES OF VARIOUS CLAY MATERIALS AND EXTENDS THE DISCUSSION TO PILLARED CLAYS AND REAGENTS SUPPORTED ON CLAY MATERIALS. A VARIET...

148

21 CFR 864.8950 - Russell viper venom reagent.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Reagents § 864.8950 Russell viper venom reagent. (a) Identification. Russell viper...

2013-04-01

149

21 CFR 864.8100 - Bothrops atrox reagent.  

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Reagents § 864.8100 Bothrops atrox reagent. (a) Identification. A Bothrops...

2014-04-01

150

21 CFR 864.8950 - Russell viper venom reagent.  

Code of Federal Regulations, 2010 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Reagents § 864.8950 Russell viper venom reagent. (a) Identification. Russell viper...

2010-04-01

151

21 CFR 864.8950 - Russell viper venom reagent.  

Code of Federal Regulations, 2011 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Reagents § 864.8950 Russell viper venom reagent. (a) Identification. Russell viper...

2011-04-01

152

21 CFR 864.4010 - General purpose reagent.  

Code of Federal Regulations, 2011 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Specimen Preparation Reagents § 864.4010 General purpose reagent. (a) A general...

2011-04-01

153

21 CFR 864.8950 - Russell viper venom reagent.  

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Reagents § 864.8950 Russell viper venom reagent. (a) Identification. Russell viper...

2014-04-01

154

21 CFR 864.4010 - General purpose reagent.  

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Specimen Preparation Reagents § 864.4010 General purpose reagent. (a) A general...

2014-04-01

155

21 CFR 864.8100 - Bothrops atrox reagent.  

Code of Federal Regulations, 2010 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Reagents § 864.8100 Bothrops atrox reagent. (a) Identification. A Bothrops...

2010-04-01

156

21 CFR 864.8950 - Russell viper venom reagent.  

Code of Federal Regulations, 2012 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Reagents § 864.8950 Russell viper venom reagent. (a) Identification. Russell viper...

2012-04-01

157

21 CFR 864.8540 - Red cell lysing reagent.  

Code of Federal Regulations, 2011 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Reagents § 864.8540 Red cell lysing reagent. (a) Identification. A red cell...

2011-04-01

158

21 CFR 864.8100 - Bothrops atrox reagent.  

Code of Federal Regulations, 2012 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Reagents § 864.8100 Bothrops atrox reagent. (a) Identification. A Bothrops...

2012-04-01

159

21 CFR 864.4010 - General purpose reagent.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Specimen Preparation Reagents § 864.4010 General purpose reagent. (a) A general...

2013-04-01

160

21 CFR 864.4010 - General purpose reagent.  

Code of Federal Regulations, 2010 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Specimen Preparation Reagents § 864.4010 General purpose reagent. (a) A general...

2010-04-01

161

21 CFR 864.8100 - Bothrops atrox reagent.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Reagents § 864.8100 Bothrops atrox reagent. (a) Identification. A Bothrops...

2013-04-01

162

Nano-high-performance liquid chromatography with online precleaning coupled to inductively coupled plasma mass spectrometry for the analysis of lanthanide-labeled peptides in tryptic protein digests.  

PubMed

Low background signals are an indispensable prerequisite for accurate quantification in bioanalytics. This poses a special challenge when using derivatized samples, where excess reagent concentrations are increasing the background signal. Precleaning steps often are time-consuming and usually lead to analyte losses. In this study, a set of labeled model peptides and a protein digest was analyzed using inductively coupled plasma mass spectrometry (ICPMS), coupled to nano ion pairing reversed-phase high-performance liquid chromatography (nano-IP-RP-HPLC). In addition, matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) was used for peptide identification. Peptides were labeled with lanthanide metals using bifunctional DOTA-based (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) reagents. The resulting metal excess was removed online during nano-HPLC, by trapping the labeled peptides on a C18-precolumn and washing them prior to their elution to the analytical column. Different ion pairing reagents like TFA (trifluoroacetic acid) and HFBA (heptafluorobutyric acid) were used in the study to enhance interactions of the different peptide species with the C18 material of the precolumn. HFBA even allowed the detection of a highly hydrophilic peptide that was not retained using TFA. It was shown that for the mixture of labeled model peptides, even a short 3 min washing step already enhanced the removal of the excess reagents significantly, whereas peptide losses were observable starting with a 10 min washing time. A 6 min washing time was determined to be the best parameter for lowering the lanthanide metal background while maintaining maximum peptide recovery. Alternative precleaning setups using EDTA to enhance the removal of free metal or an offline approach using solid phase extraction did not show promising results. The application of the optimized method to labeled peptides in a lysozyme digest showed results comparable to those obtained with model peptides. PMID:23373771

Holste, Angela; Tholey, Andreas; Hung, Chien-Wen; Schaumlöffel, Dirk

2013-03-19

163

Organic Syntheses Using Polymeric Supports, Polymeric Reagents, and Polymeric Catalysts  

Microsoft Academic Search

In conventional organic syntheses, organic molecules are treated with a reagent or reagents and the transformed organic molecules, now termed the product, are isolated. The various steps in a conventional organic synthesis may be represented schematically as in Fig. 1. In this scheme a low molecular weight molecule (A) is treated with a low molecular weight reagent (B). When the

N. K. Mathur; R. E. Williams

1976-01-01

164

21 CFR 660.30 - Reagent Red Blood Cells.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Reagent Red Blood Cells. 660.30 Section 660.30 Food and Drugs...SUBSTANCES FOR LABORATORY TESTS Reagent Red Blood Cells § 660.30 Reagent Red Blood Cells. (a) Proper name and definition....

2010-04-01

165

21 CFR 58.83 - Reagents and solutions.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Reagents and solutions. 58.83 Section 58.83 Food and Drugs...Facilities Operation § 58.83 Reagents and solutions. All reagents and solutions in the laboratory areas shall be...

2010-04-01

166

21 CFR 58.83 - Reagents and solutions.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Reagents and solutions. 58.83 Section 58.83 Food and Drugs...Facilities Operation § 58.83 Reagents and solutions. All reagents and solutions in the laboratory areas shall be...

2011-04-01

167

21 CFR 660.30 - Reagent Red Blood Cells.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2010-04-01 true Reagent Red Blood Cells. 660.30 Section 660.30 Food and Drugs...SUBSTANCES FOR LABORATORY TESTS Reagent Red Blood Cells § 660.30 Reagent Red Blood Cells. (a) Proper name and definition....

2011-04-01

168

Novel spray reagents for plant pigments  

Microsoft Academic Search

Paper chromatographic procedures involving the use of butanol?acetic acid?water (4?1?5 v\\/v) as solvent and 1 % aqueous uranyl acetate or uranyl nitrate solution as spray reagent, have been developed for detection of plant pigments when present in amounts of at least 5 ?g each. Quinones, flavones and some of their O-glycosides having at least one hydroxyl group adjacent to carbonyl

K. P. Tiwari; P. K. Minocha; Y. K. S. Rathore; M. Masood

1979-01-01

169

Treatment of textile wastewater by Fenton's reagent  

Microsoft Academic Search

Treatment of textile wastewaters from a dyeing and finishing mill by Fenton's reagent is investigated. The experimental results are assessed in terms of COD and color (turbidity) reductions to determine the treatment efficiency of the Fenton's process. Operating variables, such as the pH, amounts of H2O2 and FeSO4, time of Fenton's treatment and amounts of polyaluminum chloride (PAC) and polymer,

S. H. Lin; C. F. Peng

1995-01-01

170

Chemical composition of Schiff's reagent crystals.  

PubMed

Crystals were prepared by adding 0.04 M sulfuric acid to a Schiff's reagent made with 2.5 g pararosaniline (PR) chloride dissolved in a saturated SO2 solution. Elemental analysis of the crystals gave the composition C19H21N3S2O7.4H2O which corresponds to the sulfate of pararosanilinesulfonic acid (PRSA) tetrahydrate. The moisture content was ca. 5%. A reagent reconstituted by dissolving 0.2 grams of crystals in HCl 0.1 N contains ca. 3.5 x 10(-3) M or 0.11% PR. A solution prepared with 2.5 g PR in 100 ml O.1 N HCl plus 0.04 M M K2S2O5 gave only a few crystals after 0.04 M sulfuric acid was added. The PR content, determined colorimetrically, was 0.25% compared with 1.35% in saturated SO2. The per cent dye loss during charcoal purification was also higher. The low concentration of PR, caused both by the lower solubility and by the larger loss during charcoal purification explains the poor yield of crystals of a reagent prepared in HCl/K2S2O5, compared to a reagent prepared in saturated SO2. After crystallization is complete, the crystals are in equilibrium with a concentration of 0.2% of PR in the supernatant: when the initial concentration is close to this value crystallization is negligible or completely fails. PMID:8835187

Galassi, L; De Napoli, F

1995-01-01

171

Synthesis of N-Fmoc-(2S,3S,4R)-3,4-dimethylglutamine: An application of lanthanide-catalyzed transamidation.  

PubMed

N-Fmoc-(2S,3S,4R)-3,4-dimethylglutamine (6) was synthesized from tert-butyl N-Boc-(2S,3S,4R)-dimethylpyroglutamate (13). This synthesis involved selective deprotection of a Boc group from a lactam nitrogen in the presence of a tert-butyl ester, Fmoc protection of the lactam, and a lanthanide-catalyzed transamidation reaction of the Fmoc-protected lactam, using ammonia and dimethylaluminum chloride. The scope of Lewis acid-catalyzed transamidation of acylated lactams was explored through the variation of lanthanide, lactam, acyl group, amine, and aluminum reagent. The reactivity of various metal triflates was found to vary in the following qualitative order: Yb approximately Sc > Er approximately Eu approximately Sm > Ce approximately Ag(I) > Cu(II) approximately Zn. Intriguingly, catalysis was only observed when ammonia was the nitrogen nucleophile; addition of other amidoaluminum complexes to acyl lactams was found to be insensitive to the addition of lanthanides. PMID:16050680

Calimsiz, Selçuk; Lipton, Mark A

2005-08-01

172

Spotlights on Recent JACS Publications FLUORESCENT LANTHANIDES TRIGGERED BY  

E-print Network

designed for one analyte, which limits the broad utility of lanthanide metal- containing fluorescent probes that can be sensors for pH, citrate in urine, or singlet oxygen inside cells. The new probe contains

Leigh, David A.

173

On the Suitability of Lanthanides as Actinide Analogs  

E-print Network

lanthanide and actinide coordination behavior that is becoming important in the field of radionuclide separations andlanthanides convenient actinide surrogates in structural modeling makes them more a nuisance than a boon for the actinide and separations

Szigethy, Geza

2008-01-01

174

Noncovalent tagging proteins with paramagnetic lanthanide complexes for protein study.  

PubMed

The site-specific labeling of proteins with paramagnetic lanthanides offers unique opportunities for NMR spectroscopic analysis in structural biology. Herein, we report an interesting way of obtaining paramagnetic structural restraints by employing noncovalent interaction between a lanthanide metal complex, [Ln(L)3](n-) (L=derivative of dipicolinic acid, DPA), and a protein. These complexes formed by lanthanides and DPA derivatives, which have different substitution patterns on the DPA derivatives, produce diverse thermodynamic and paramagnetic properties when interacting with proteins. The binding affinity of [Ln(L)3](n-) with proteins, as well as the determined paramagnetic tensor, are tunable by changing the substituents on the ligands. These noncovalent interactions between [Ln(L)3](n-) and proteins offer great opportunities in the tagging of proteins with paramagnetic lanthanides. We expect that this method will be useful for obtaining multiple angles and distance restraints of proteins in structural biology. PMID:23450718

Wei, Zhen; Yang, Yin; Li, Qing-Feng; Huang, Feng; Zuo, Hui-Hui; Su, Xun-Cheng

2013-04-26

175

Separation of actinides from lanthanides utilizing molten salt electrorefining  

SciTech Connect

TRUMP-S (TRansUranic Management through Pyropartitioning Separation) is a pyrochemical process being developed to separate actinides form fission products in nuclear waste. A key process step involving molten salt electrorefining to separate actinides from lanthanides has been studied on a laboratory scale. Electrorefining of U, Np, Pu, Am, and lanthanide mixtures from molten cadmium at 450 C to a solid cathode utilizing a molten chloride electrolyte resulted in > 99% removal of actinides from the molten cadmium and salt phases. Removal of the last few percent of actinides is accompanied by lowered cathodic current efficiency and some lanthanide codeposition. Actinide/lanthanide separation ratios on the cathode are ordered U > Np > Pu > Am and are consistent with predictions based on equilibrium potentials.

Grimmett, D.L.; Fusselman, S.P.; Roy, J.J.; Gay, R.L. [Rockwell International, Canoga Park, CA (United States). Rocketdyne Div.; Krueger, C.L.; Storvick, T.S. [Univ. of Missouri, Columbia, MO (United States). Research Reactor Facility; Inoue, T.; Hijikata, T. [Central Research Inst. of Electric Power Industry, Tokyo (Japan). Komae Research Lab.; Takahashi, N. [Kawasaki Heavy Industries, Ltd., Tokyo (Japan). Nuclear Systems Div.

1996-10-01

176

Lanthanide co-ordination frameworks: Opportunities and diversity  

Microsoft Academic Search

Significant successes have been made over recent years in preparing co-ordination framework polymers that show macroscopic material properties, but in the vast majority of cases this has been achieved with d-block metal-based systems. Lanthanide co-ordination frameworks also offer attractive properties in terms of their potential applications as luminescent, non-linear optical and porous materials. However, lanthanide-based systems have been far less

Robert J. Hill; De-Liang Long; Peter Hubberstey; Martin Schroeder; Neil R.. Champness

2005-01-01

177

Lighting up cells with lanthanide self-assembled helicates  

PubMed Central

Lanthanide bioprobes and bioconjugates are ideal luminescent stains in view of their low propensity to photobleaching, sharp emission lines and long excited state lifetimes permitting time-resolved detection for enhanced sensitivity. We show here how the interplay between physical, chemical and biochemical properties allied to microfluidics engineering leads to self-assembled dinuclear lanthanide luminescent probes illuminating live cells and selectively detecting biomarkers expressed by cancerous human breast cells. PMID:24511387

Bunzli, Jean-Claude G.

2013-01-01

178

Lanthanide coordination polymers: Synthesis, diverse structure and luminescence properties  

NASA Astrophysics Data System (ADS)

The new semirigid exo-bidentate ligand incorporating furfurysalicylamide terminal groups, namely, 1,4-bis{[(2?-furfurylaminoformyl)phenoxyl]methyl}-2,5-bismethylbenzene (L) was synthesized and used as building blocks for constructing lanthanide coordination polymers with luminescent properties. The series of lanthanide nitrate complexes have been characterized by elemental analysis, IR spectroscopy, and X-ray diffraction analysis. The semirigid ligand L, as a bridging ligand, reacts with lanthanide nitrates forming three distinct structure types: chiral noninterpenetrated two-dimensional (2D) honeycomblike (6,3) (hcb, Schläfli symbol 63, vertex symbol 6 6 6) topological network as type I, 1D zigzag chain as type II and 1D trapezoid ladder-like chain as type III. The structural diversities indicate that lanthanide contraction effect played significant roles in the structural self-assembled process. The luminescent properties of EuIII, TbIII and DyIII complexes are discussed in detail. Due to the good match between the lowest triplet state of the ligand and the resonant energy level of the lanthanide ion, the lanthanide ions in EuIII, TbIII and DyIII complexes can be efficiently sensitized by the ligand.

Song, Xue-Qin; Lei, Yao-Kun; Wang, Xiao-Run; Zhao, Meng-Meng; Peng, Yun-Qiao; Cheng, Guo-Quan

2014-10-01

179

Shelf-stable electrophilic trifluoromethylating reagents: A brief historical perspective  

PubMed Central

Summary Since the discovery by Yagupolskii and co-workers that S-trifluoromethyl diarylsulfonium salts are effective for the trifluoromethylation of thiophenolates, the design and synthesis of electrophilic trifluoromethylating reagents have been extensively researched in both academia and industry, due to the significant unique features that trifluoromethylated compounds have in pharmaceuticals, agricultural chemicals, and functional materials. Several effective reagents have been developed by the groups of Yagupolskii, Umemoto, Shreeve, Adachi, Magnier, Togni and Shibata. Due to the high stability and reactivity of these reagents, a series of Umemoto reagents, Togni reagent and Shibata reagent are now commercially available. In this review, we wish to briefly provide a historical perspective of the development of so-called “shelf-stable electrophilic trifluoromethylating reagents”, although this field is in constant development. PMID:20703379

Matsnev, Andrej

2010-01-01

180

Luminescence of Lanthanide-Dimethyl Sulfoxide Compound Solutions  

SciTech Connect

Dimethyl sulfoxide (DMSO) has the ability to penetrate living tissues without causing significant damage. Of foremost importance to our understanding of the possible functions of DMSO in biological systems is its ability to replace some of the water molecules associated with the cellular constituents, or to affect the structure of the omnipresent water. Luminescence probes have been widely used for biological studies such as labeling, imaging and detection. Luminescence probes formed in DMSO may find new applications. Here, luminescence compounds formed by refluxing lanthanide nitrates of Ce, La, Tb, Yb, Nd, Gd and Eu in DMSO are reported and their luminescence properties investigated. Based on their luminescence spectral properties, the compounds can be classified into four classes. For compounds-I with Yb, Ce, and La, the excitation and emission spectra are very broad and their excitation or emission peaks are shifted to longer wavelengths when the monitored emission or excitation wavelength is longer . For compounds-II with Gd and Nd, both the excitation and emission spectra are very broad but their emission wavelengths change little at different excitation wavelengths. For Tb-DMSO as compound-III, both the typical emissions from the f - f transitions of Tb3+ and a broad emission at 445 nm are observed. At low temperatures of reaction, the f - f emissions are dominant, while at high temperatures such as 180 oC of reaction, the broad emission at 445 nm is dominant. For compound-IV with Eu-DMSO compounds, the dominant emissions are from the f - f transitions of Eu3+ and only a weak broad emission is observed, which is likely from the d - f transition of Eu2+ rather than from the metal to ligand charge transfer states.

Yao, Mingzhen; Li, Yuebin; Hossu, Marius; Joly, Alan G.; Liu, Zhongxin; Liu, Zuli; Chen, Wei

2011-08-04

181

21 CFR 866.3235 - Epstein-Barr virus serological reagents.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Epstein-Barr virus serological reagents. 866.3235 Section...Reagents § 866.3235 Epstein-Barr virus serological reagents. (a) Identification. Epstein-Barr virus serological reagents are devices...

2013-04-01

182

21 CFR 866.3900 - Varicella-zoster virus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Varicella-zoster virus serological reagents. 866.3900 ...Reagents § 866.3900 Varicella-zoster virus serological reagents. (a) Identification. Varicella-zoster virus serological reagents are...

2010-04-01

183

21 CFR 866.3900 - Varicella-zoster virus serological reagents.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Varicella-zoster virus serological reagents. 866.3900 ...Reagents § 866.3900 Varicella-zoster virus serological reagents. (a) Identification. Varicella-zoster virus serological reagents are...

2012-04-01

184

21 CFR 866.3900 - Varicella-zoster virus serological reagents.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Varicella-zoster virus serological reagents. 866.3900 ...Reagents § 866.3900 Varicella-zoster virus serological reagents. (a) Identification. Varicella-zoster virus serological reagents are...

2013-04-01

185

21 CFR 866.3235 - Epstein-Barr virus serological reagents.  

...2014-04-01 false Epstein-Barr virus serological reagents. 866.3235 Section...Reagents § 866.3235 Epstein-Barr virus serological reagents. (a) Identification. Epstein-Barr virus serological reagents are devices...

2014-04-01

186

21 CFR 866.3900 - Varicella-zoster virus serological reagents.  

...2014-04-01 false Varicella-zoster virus serological reagents. 866.3900 ...Reagents § 866.3900 Varicella-zoster virus serological reagents. (a) Identification. Varicella-zoster virus serological reagents are...

2014-04-01

187

Separation of Lanthanide Ions with Kläui Ligand Resin  

SciTech Connect

Separation and pre-concentration of the desired analyte is often a critical step in many radioanalytical methods. Current procedures for separating and concentrating analytes for detection are complex, and can be both expensive and time consuming. Therefore, the purpose of this research is to develop an alternative method of separating lanthanide ions through the use of an extraction chromatography resin containing a Klaui ligand salt. This research is a continuation of a concerted effort to develop new methods of detecting small concentrations of radionuclides and lanthanides using Klaui ligands. The Klaui ligands, C5Me5Co(OP(OR)2)3- (R=Me, Et, n-Pr) (LOR-), have unique affinity for lanthanide and actinide ions in the presence of competing metal ions. The use of 1 wt% NaLOR (R=Et or n-Pr) adsorbed onto resin support has been shown to extract lanthanide ions from aqueous nitric acid solutions of different concentrations. In order to further evaluate the utility of these materials in radiochemical separation, the selectivity of the resins for the different lanthanide ions was examined by measuring the distribution coefficients (Kd) for a series of lanthanides over a range of solution conditions. Based on prior research with actinide ions, it was hypothesized that the lanthanide ions would bond strongly with the Klaui ligands. The success of this research is important, because it will assist in expanding and improving current automated radiochemical methods, which will decrease the cost of developing and implementing radiochemical methods. To date, Kd values have been determined for Eu+3, Nd+3 and Pr+3 under varying nitric acid (HNO3) concentration, using a resin consisting of 1.0 wt% NaLOPr on Amberlite XAD-7HP. The dependence of the Kd values for Eu+3 has also been examined as a function of the ligand-to-europium ratio and the nitrate concentration. Decreasing Kd values were obtained upon increasing the nitric acid concentration, indicating protonation of the ligand, which competes with binding of the lanthanide ions. As expected, increasing the Klaui ligand-to-europium ratio results in increasing Kd, but no conclusions could be made from these data regarding stoichiometry of the complex formed on the resin. No dependence of the Kd on the nitrate concentration was observed, supporting the notion that the HNO3 dependence is dominated by the presence of the acidic hydronium ion (as opposed to the nitrate ion). Future work will involve the determination of the Kd values for the remainder of the lanthanide series to further assess the potential of the Klaui ligand for intra-group lanthanide separations.

Granger, Trinity D.; Henry, Victoria A.; Latesky, Stanley

2007-07-01

188

EXPERIENCE SUMMARY Development of the TALSqueak (Trivalent Actinide Lanthanide Separation using QUicker Extractants and  

E-print Network

EXPERIENCE SUMMARY Research Development of the TALSqueak (Trivalent Actinide Lanthanide Separation using QUicker Extractants and Aqueous Komplexants) process for separations of trivalent lanthanides from of ternary complexes for improved radiochemical separations Precursor monitoring of aggregates in solvent

189

Facile Oxidative Rearrangements Using Hypervalent Iodine Reagents  

PubMed Central

Aromatic substituents migrate in a novel oxidative cyclization mediated by iodine(III) reagents. 4-Arylbut-3-enoic acids are cyclized and rearranged to 4-arylfuran-2(5H)-ones by hypervalent iodine compounds in good to excellent yields under mild reaction conditions. Other ring sizes are also accessible. The mechanism of the reaction is described in detail, and calculations highlight the cationic nature of the intermediates in the rearrangement. The fast access to heavily substituted furanones is used for the synthesis of biologically active derivatives. PMID:24551514

Singh, Fateh V; Rehbein, Julia; Wirth, Thomas

2012-01-01

190

Aptamers as affinity reagents in an integrated electrophoretic lab-on-a-chip platform.  

PubMed

Nucleic acid based affinity reagents (e.g., aptamers) offer several possible advantages over antibodies as specific recognition elements in biochemical assays. Besides offering improved cost and stability, aptamers are ideal for rapid electrophoretic analysis due to their low molecular weight and high negative charge. While aptamers have proven well-suited for affinity-shift electrophoretic analysis, demonstrating a fully integrated aptamer-based assay platform represents an important achievement toward low-cost point-of-care analysis, particularly for remote or resource poor settings where cost and ambient stability of reagents is a key consideration. Here we perform and evaluate the suitability of aptamer-based affinity assays for two clinically relevant target analytes (IgE using a known aptamer and NF-?B using a thio-modified aptamer) in an integrated electrophoretic gel-shift platform. Key steps of (i) mixing sample with aptamer, (ii) buffer exchange, and (iii) preconcentration of sample were successfully integrated on-chip upstream of a fluorescence-based gel-shift analysis step. This approach, utilizing a size-exclusion membrane optimized here for aptamer retention and preconcentration with sample, enables automated sample-to-answer for trace analytes in 10 min or less. We addressed notable nonspecific interference from serum proteins by adding similar nucleic acid competitors to suppress such interactions with the aptamer. Nanomolar sensitivities were demonstrated and integrated preconcentration of sample provides an important means of further improving detection sensitivities. Aptamers proved superior in many respects to antibody reagents, particularly with regard to speed and resolution of gel-shifts associated with specific binding to target. PMID:20945866

Hecht, Ariel H; Sommer, Greg J; Durland, Ross H; Yang, Xianbin; Singh, Anup K; Hatch, Anson V

2010-11-01

191

Collection of radon with solid oxidizing reagents  

SciTech Connect

Although it is generally considered to be inert, radon reacts spontaneously at ambient temperature with a number of fluorine-containing compounds, including dioxygenyl salts, fluoronitrogen salts, and halogen fluoride-metal fluoride complexes. A method for the collection of radon from air, using either dioxygenyl hexafluoroantimonate (O/sub 2//sup +/SbF/sub 6//sup -/) or hexafluoroiodine hexafluoroantimonate (IF/sub 6//sup +/SbF/sub 6//sup -/) reagent, is described. The air is passed though a drying tube and then through a bed of the reagent, which captures radon as a nonvolatile product. In tests with radon-air mixtures containing 45-210000 pCi/L of radon-222, more than 99% of the radon was retained by beds of powders (2.3-3.0 g of compound/cm/sup 2/) and pellets (7.5-10.9 g of compound/cm/sup 2/). The gas mixtures were designed to simulate radon-contaminated atmospheres in underground uranium mines. No dependence of collection efficiency upon radon concentration was observed. The method can be used for the analysis of radon-222 (by measurement of the ..gamma.. emissions of the short-lived daughters, lead-214 and bismuth-214) and the purification of small volumes of air.

Stein, L.; Hohorst, F.A.

1982-07-01

192

Combinatorial library design from reagent pharmacophore fingerprints.  

PubMed

Combinatorial and parallel chemical synthesis technologies are powerful tools in early drug discovery projects. Over the past couple of years an increased emphasis on targeted lead generation libraries and focussed screening libraries in the pharmaceutical industry has driven a surge in computational methods to explore molecular frameworks to establish new chemical equity. In this chapter we describe a complementary technique in the library design process, termed ProSAR, to effectively cover the accessible pharmacophore space around a given scaffold. With this method reagents are selected such that each R-group on the scaffold has an optimal coverage of pharmacophoric features. This is achieved by optimising the Shannon entropy, i.e. the information content, of the topological pharmacophore distribution for the reagents. As this method enumerates compounds with a systematic variation of user-defined pharmacophores to the attachment point on the scaffold, the enumerated compounds may serve as a good starting point for deriving a structure-activity relationship (SAR). PMID:20981522

Chen, Hongming; Engkvist, Ola; Blomberg, Niklas

2011-01-01

193

A Simple Empirical Analysis of the Enthalpies of Formation of Lanthanide Halides and Oxides.  

ERIC Educational Resources Information Center

Proposes a simple and general method whereby the lattice energies of lanthanide(II) and (IV) compounds are derived directly from those found experimentally for the corresponding lanthanide(III) compounds. The method is applicable to all lanthanide halides and oxides and involves calculations which can be easily and quickly performed by students.…

Smith, Derek W.

1986-01-01

194

From Antenna to Assay: Lessons Learned in Lanthanide Luminescence  

SciTech Connect

Ligand-sensitized luminescent lanthanide(III) complexes are of considerable current interest due to their unique photophysical properties (micro- to millisecond lifetimes, characteristic and narrow emission bands, and large Stokes shifts), which make them well suited to serve as labels in fluorescence-based bioassays. The long-lived Ln(III) emission can be temporally resolved from scattered light and background fluorescence, resulting in vastly enhanced measurement sensitivity. One of the challenges in this field is the design of sensitizing ligands that provide highly emissive Ln(III) complexes that also possess sufficient stability and aqueous solubility required for practical applications. In this account we give an overview of some of the general properties of the trivalent lanthanides and follow with a summary of advances made in our laboratory in the development of highly luminescent Tb(III) and Eu(III) complexes for applications in biotechnology. A focus of our research has been the optimization of these compounds as potential commercial agents for use in Homogeneous Time Resolved Fluorescence (HTRF) technology, the requirements and current use of which will be briefly discussed. Our approach involves developing high-stability octadentate Tb(III) and Eu(III) complexes that rely on all-oxygen donor atoms as well as using multi-chromophore chelates to increase molar absorptivity compared to earlier examples that utilize a single pendant antenna chromophore. We have found that ligands based on 2-hydroxyisophthalamide (IAM) provide exceptionally emissive Tb(III) complexes with quantum yield values up to ca. 60%. Solution thermodynamic studies have indicated that these complexes are stable at the nanomolar concentrations required for commercial assays. Through synthetic modification of the IAM-chromophore, in conjunction with time-dependent density functional theory (TD-DFT) calculations, we have developed a method to predict absorption and emission properties of these chromophores as a tool to guide ligand design. Additionally we have investigated chiral IAM ligands that yield Tb(III) complexes possessing both high quantum yield values and strong circularly polarized luminescence (CPL) activity. To efficiently sensitize Eu(III) emission, we have utilized ligands based on the 1-hydroxypyridin-2-one (1,2-HOPO) chelate, which are remarkable since they combine both excellent photophysical properties in addition to exceptional aqueous stabilities. A more compete understanding of this chromophore has been achieved by combining low temperature phosphorescence measurements with the same TD-DFT approach used with the IAM system. Also, Eu(III) complexes with strong CPL activity have been obtained through preparation of chiral 1,2-HOPO ligands. Using the unique spectroscopic properties of Eu(III), we have also undertaken the kinetic analysis of radiative and non-radiative decay pathways for a series of complexes, which has highlighted the importance of the metal ion symmetry on the ensuing photophysical properties. Lastly, the commercial development of a Tb-IAM compound that offers improved performance in the common HTRF platform and has the potential to vastly improve the sensitivity of measurements carried out using this technique is presented.

Moore, Evan; Samuel, Amanda; Raymond, Kenneth

2008-09-25

195

Lanthanide-doped hollow nanomaterials as theranostic agents.  

PubMed

The field of theranostics has sprung up to achieve personalized medicine. The theranostics fuses diagnostic and therapeutic functions, empowering early diagnosis, targeted drug delivery, and real-time monitoring of treatment effect into one step. One particularly attractive class of nanomaterials for theranostic application is lanthanide-doped hollow nanomaterials (LDHNs). Because of the existence of lanthanide ions, LDHNs show outstanding fluorescent and paramagnetic properties, enabling them to be used as multimodal bioimaging agents. Synchronously, the huge interior cavities of LDHNs are able to be applied as efficacious tools for storage and delivery of therapeutic agents. The LDHNs can be divided into two types based on difference of component: single-phase lanthanide-doped hollow nanomaterials and lanthanide-doped hollow nanocomposites. We describe the synthesis of first kind of nanomaterials by use of hard template, soft template, template-free, and self-sacrificing template method. For lanthanide-doped hollow nanocomposites, we divide the preparation strategies into three kinds (one-step, two-step, and multistep method) according to the synthetic procedures. Furthermore, we also illustrate the potential bioapplications of these LDHNs, including biodetection, imaging (fluorescent imaging and magnetic resonance imaging), drug/gene delivery, and other therapeutic applications. PMID:24227795

Kang, Xiaojiao; Li, Chunxia; Cheng, Ziyong; Ma, Ping'an; Hou, Zhiyao; Lin, Jun

2014-01-01

196

40 CFR 160.83 - Reagents and solutions.  

Code of Federal Regulations, 2011 CFR

...Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS GOOD LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 160...reagents and solutions in the laboratory areas shall be labeled to...

2011-07-01

197

40 CFR 160.83 - Reagents and solutions.  

Code of Federal Regulations, 2012 CFR

...Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS GOOD LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 160...reagents and solutions in the laboratory areas shall be labeled to...

2012-07-01

198

40 CFR 160.83 - Reagents and solutions.  

Code of Federal Regulations, 2010 CFR

...Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS GOOD LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 160...reagents and solutions in the laboratory areas shall be labeled to...

2010-07-01

199

40 CFR 160.83 - Reagents and solutions.  

Code of Federal Regulations, 2013 CFR

...Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS GOOD LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 160...reagents and solutions in the laboratory areas shall be labeled to...

2013-07-01

200

Thermodynamics of the lanthanide with organic acids  

SciTech Connect

The thermodynamic parameters (..delta..G, ..delta..H, and ..delta..S) of the formation of the europium monooxalate complex has been determined at 25/sup 0/C and 0.1 M ionic strength (NaClO/sub 4/) by means of solvent extraction. ..delta..G values show that the 5-membered oxalate ring is more stable than those of longer chain aliphatic dicarboxylates (malonate, succinate, glutarate or adipate). This effect is reflected in the complexation entropy values, ..delta..S/sub 101/. The stability constants for trivalent Eu complexes with benzene polycarboxylates (trimetallitate, hemimellitate, and pyromellitate) were measured using a solvent extraction system at 25/sup 0/C and 0.1 M ionic strength (NaClO/sub 4/). The values measured at varying hydrogen ion concentrations show that either protonated species do not form or their formation constants are not significant enough to influence the overall observed conditional constants. The enthalpies for lanthanide hemimellitate and pyromellitate were determined by calorimetric titration. Solvent extraction studies were conducted for Eu and Am complexes with mellitate at 0.1 M and 2.0 M (NaClO/sub 4/). In this case the stability constants for protonated species, MHL and MH/sub 2/L, were determined. The effective charges calculated from the experimental free energy values of these polycarboxylates indicate a significant charge polarization in the ligand which could be induced through inductive and/or resonance effects.

Al-Ansi, T.Y.

1985-01-01

201

Advances in synthetic peptides reagent discovery  

NASA Astrophysics Data System (ADS)

Bacterial display technology offers a number of advantages over competing display technologies (e.g, phage) for the rapid discovery and development of peptides with interaction targeted to materials ranging from biological hazards through inorganic metals. We have previously shown that discovery of synthetic peptide reagents utilizing bacterial display technology is relatively simple and rapid to make laboratory automation possible. This included extensive study of the protective antigen system of Bacillus anthracis, including development of discovery, characterization, and computational biology capabilities for in-silico optimization. Although the benefits towards CBD goals are evident, the impact is far-reaching due to our ability to understand and harness peptide interactions that are ultimately extendable to the hybrid biomaterials of the future. In this paper, we describe advances in peptide discovery including, new target systems (e.g. non-biological materials), advanced library development and clone analysis including integrated reporting.

Adams, Bryn L.; Sarkes, Deborah A.; Finch, Amethist S.; Stratis-Cullum, Dimitra N.

2013-05-01

202

Coat-nitrocarburizing using triazine polymer reagent  

NASA Astrophysics Data System (ADS)

A chemico-thermal treatment process, coat-nitrocarburizing, has been developed for use on iron and steel. The process consists of treating the workpiece with a coat that forms on the surface from the gaseous products of sublimation and decomposition of a triazine polymer reagent in a closed volume. The process can be used over a wide range of temperatures, either below the eutectoid transformation temperature in the Fe-N-C system for low-temperature nitrocarburizing, or above this temperature for hightemperature nitrocarburizing in different applications. The process is very simple, easily controlled, and is economic. In addition, it is a nonpolluting process, unlike conventional chemico-thermal treatment processes that discharge harmful gases into the atmosphere.

Wen, Li.; Shi, J.; Smith, R. W.

1993-02-01

203

Nature of the electronic band gap in lanthanide oxides  

NASA Astrophysics Data System (ADS)

Accurate electronic structures of the technologically important lanthanide/rare-earth sesquioxides (Ln2O3, with Ln=La,⋯,Lu) and CeO2 have been calculated using hybrid density functionals HSE03, HSE06, and screened exchange (sX-LDA). We find that these density functional methods describe the strongly correlated Ln f electrons as well as the recent G0W0@LDA+U results, generally yielding the correct band gaps and trends across the Ln period. For HSE, the band gap between O 2p states and lanthanide 5d states is nearly independent of the lanthanide, while the minimum gap varies as filled or empty Ln 4f states come into this gap. sX-LDA predicts the unoccupied 4f levels at higher energies, which leads to a better agreement with experiments for Sm2O3, Eu2O3, and Yb2O3.

Gillen, Roland; Clark, Stewart J.; Robertson, John

2013-03-01

204

Synthesis and chemistry of yttrium and lanthanide metal complexes  

SciTech Connect

The objective of this research project is to determine the special features of complexes of yttrium and the lanthanide metals which will allow the design and synthesis of materials with unique chemical, physical, and catalytic properties. Past studies of yttrium and lanthanide metal alkyl and hydride complexes stabilized by cyclopentadienyl co-ligands have shown that a substantial, often singular, organometallic chemistry is available via these metals. More extensive utilization of the chemical opportunities available through yttrium and the lanthanides would be possible, however, if stabilizing ancillary ligand systems less sensitive to oxidation and protonolysis than cyclopentadienides could be developed. Alkoxide ligands are attractive in this regard and our recent research had focused on alkoxides and the special opportunities they can provide to these metals. 6 refs., 10 figs.

Evans, W.J.

1991-09-01

205

Enhancing luminescence in lanthanide-doped upconversion nanoparticles.  

PubMed

The enthusiasm for research on lanthanide-doped upconversion nanoparticles is driven by both a fundamental interest in the optical properties of lanthanides embedded in different host lattices and their promise for broad applications ranging from biological imaging to photodynamic therapy. Despite the considerable progress made in the past decade, the field of upconversion nanoparticles has been hindered by significant experimental challenges associated with low upconversion conversion efficiencies. Recent experimental and theoretical studies on upconversion nanoparticles have, however, led to the development of several effective approaches to enhancing upconversion luminescence, which could have profound implications for a range of applications. Herein we present the underlying principles of controlling energy transfer through lanthanide doping, overview the major advances and key challenging issues in improving upconversion luminescence, and consider the likely directions of future research in the field. PMID:25204638

Han, Sanyang; Deng, Renren; Xie, Xiaoji; Liu, Xiaogang

2014-10-27

206

Chiral lanthanide complexes: coordination chemistry, spectroscopy, and catalysis.  

PubMed

The coordination chemistry and catalytic applications of organometallic and related lanthanide complexes bearing chiral oxazoline ligands is an area that has been largely underdeveloped, in comparison to complexes based upon lanthanide triflates for use in Lewis acid catalysis. In this article we report on the coordination chemistry of the bis(oxazolinylphenyl)amide (BOPA) ligand with lanthanide alkyl and amide co-ligands (Ln = Y, La, Pr, Nd, Sm). Their structural and spectroscopic characterisation are reported, including an assessment of their photophysical properties using luminescence spectroscopy, and are supported by density functional calculations. The application of these complexes in the hydroamination/cyclisation of aminoalkenes, and in the ring-opening polymerisation of rac-lactide is reported. PMID:24577185

Bennett, Stacey D; Core, Bryony A; Blake, Matthew P; Pope, Simon J A; Mountford, Philip; Ward, Benjamin D

2014-04-21

207

Mixed lanthanide oxide nanoparticles as dual imaging agent in biomedicine  

PubMed Central

There is no doubt that the molecular imaging is an extremely important technique in diagnosing diseases. Dual imaging is emerging as a step forward in molecular imaging technique because it can provide us with more information useful for diagnosing diseases than single imaging. Therefore, diverse dual imaging modalities should be developed. Molecular imaging generally relies on imaging agents. Mixed lanthanide oxide nanoparticles could be valuable materials for dual magnetic resonance imaging (MRI)-fluorescent imaging (FI) because they have both excellent and diverse magnetic and fluorescent properties useful for dual MRI-FI, depending on lanthanide ions used. Since they are mixed nanoparticles, they are compact, robust, and stable, which is extremely useful for biomedical applications. They can be also easily synthesized with facile composition control. In this study, we explored three systems of ultrasmall mixed lanthanide (Dy/Eu, Ho/Eu, and Ho/Tb) oxide nanoparticles to demonstrate their usefulness as dual T2 MRI–FI agents. PMID:24220641

Xu, Wenlong; Bony, Badrul Alam; Kim, Cho Rong; Baeck, Jong Su; Chang, Yongmin; Bae, Ji Eun; Chae, Kwon Seok; Kim, Tae Jeong; Lee, Gang Ho

2013-01-01

208

Spectrofluorometric determination of calcium and lanthanide elements in dilute solution  

SciTech Connect

Nonradiative energy transfer from the ligand dipicolinic acid (DPA) to lanthanide ions has been used to develop a quick, easy, and reliable method to determine calcium and lanthanide elements in dilute aqueous solution. Tb(III), Eu(III), and Dy(III) are determined directly and large useful concentration ranges are available for quantitative analysis. When other metal ions are added to a solution of Tb(DPA)/sub 3//sup 3 -/, the terbium luminescence is reduced. At low metal ion concentrations, the reduction is linear for calcium and lanthanide ions and can be used as an analytical calibration curve. The detection limit is about 0.1 ..mu..g/L for the ions. The method is readily adaptable to microsampling and calcium can be determined in the presence of magnesium without interference. 4 figures, 3 tables.

Miller, T.L.; Senkfor, S.I.

1982-10-01

209

Synthesis, Characterization, and Use of a Cobalt(II) Complex as an NMR Shift Reagent.  

ERIC Educational Resources Information Center

Describes procedures for preparing acetylacetonate complex of cobalt(II), followed by spectrophotometric analysis to characterize the material, with additional characterization methods supplied by students to provide open-ended dimension for the experiment. (SK)

Goff, Harold M.; And Others

1982-01-01

210

The 3-(bromoacetamido)-propylamine hydrochloride: A novel sulfhydryl reagent and its future potential in the configurational study of S1-myosin  

NASA Technical Reports Server (NTRS)

Configurational study of S1-Myosin is an important step towards understanding force generation in muscle contraction. Previously reported NMR studies were corroborated. A new compound was synthesized, 3-(Bromoacetamido)-propylamine hydrochloride. Its potential as a sulfhydryl reagent provides an indirect but elegant approach towards future structural elucidation of S1-Myosin. The preliminary investigation has shown that this compound, BAAP, reacted with S1 in the absence of MgADP. The modified enzyme had a 2-fold increase in CaATPase activity and no detectable K-EDTA ATPase activity. Reaction of BAAP with S1 in the presence of MgADP resulted in a modified enzyme which retained a Ca-ATPase activity that was about 60 percent of the unmodified S1 and had essentially zero K-EDTA ATPase activity. Sulfhydryl titration indicated that about 1.5 and 3.5 SH groups per S1 molecule were blocked by BAAP in the absence and presence of MgADP, respectively. When coupled to a carboxyl group of EDTA, the resulting reagent could become a useful SH reagent in which chelated paramagnetic or luminescent lanthanide ions can be exploited to probe S1 conformation.

Sharma, Prasanta; Cheung, Herbert C.

1989-01-01

211

Partial oxidation of methane over bimetallic nickel–lanthanide oxides  

Microsoft Academic Search

The study of partial oxidation of methane (POM) over bimetallic nickel–lanthanide oxides was undertaken. Binary intermetallic compounds of the type LnNi (Ln=Pr, Gd, Lu) were used as bimetallic nickel–lanthanide oxides precursors and the products (NiO·Pr2NiO4, 2NiO·Gd2O3 and 2NiO·Lu2O3) were characterized by means of X-ray diffraction, X-ray photoelectron spectroscopy, Raman and temperature programmed reduction. The catalytic activity increases when gadolinium or

Ana C. Ferreira; A. M. Ferraria; A. M. Botelho do Rego; António P. Gonçalves; M. Rosário Correia; T. Almeida Gasche; Joaquim B. Branco

2010-01-01

212

Plasma mass filtering for separation of actinides from lanthanides  

NASA Astrophysics Data System (ADS)

Separating lanthanides from actinides is a key process in reprocessing nuclear spent fuel. Plasma mass filters, which operate on dissociated elements, offer conceptual advantages for such a task as compared with conventional chemical methods. The capabilities of a specific plasma mass filter concept, called the magnetic centrifugal mass filter, are analyzed within this particular context. Numerical simulations indicate separation of americium ions from a mixture of lanthanides ions for plasma densities of the order of 1012 cm-3, and ion temperatures of about 10 eV. In light of collision considerations, separating small fractions of heavy elements from a larger volume of lighter ones is shown to enhance the separation capabilities.

Gueroult, R.; Fisch, N. J.

2014-06-01

213

Applications of DFT to Lanthanides and Precious Metal Complexes  

NASA Astrophysics Data System (ADS)

Density functional theory is widely used for computational characterization of novel materials. While study of materials containing the lighter elements is commonplace, the application of these methods to the bottom of the periodic table, including the lanthanides and the heavier precious metals such as Osmium, requires careful validation. Here we present results of recent quantum mechanical studies to characterize Lanthanide/Graphene Materials and assess the suitability of DFT for these systems. Additionally, we will present recent work on similar application of DFT to characterize Os bipridine complexes.

Hurley, Margaret; Balboa, Alex; Jenkins, Amanda

2013-03-01

214

Using lanthanide ions to align troponin complexes in solution: Order of lanthanide occupancy in cardiac troponin C  

PubMed Central

The potential for using paramagnetic lanthanide ions to partially align troponin C in solution as a tool for the structure determination of bound troponin I peptides has been investigated. A prerequisite for these studies is an understanding of the order of lanthanide ion occupancy in the metal binding sites of the protein. Two-dimensional {1H, 15N} HSQC NMR spectroscopy has been used to examine the binding order of Ce3+, Tb3+, and Yb3+ to both apo- and holo-forms of human cardiac troponin C (cTnC) and of Ce3+ to holo-chicken skeletal troponin C (sTnC). The disappearance of cross-peak resonances in the HSQC spectrum was used to determine the order of occupation of the binding sites in both cTnC and sTnC by each lanthanide. For the lanthanides tested, the binding order follows that of the net charge of the binding site residues from most to least negative; the N-domain calcium binding sites are the first to be filled followed by the C-domain sites. Given this binding order for lanthanide ions, it was demonstrated that it is possible to create a cTnC species with one lanthanide in the N-domain site and two Ca2+ ions in the C-domain binding sites. By using the species cTnC•Yb3+•2 Ca2+ it was possible to confer partial alignment on a bound human cardiac troponin I (cTnI) peptide. Residual dipolar couplings (RDCs) were measured for the resonances in the bound 15N-labeled cTnI129–148 by using two-dimensional {1H, 15N} inphase antiphase (IPAP) NMR spectroscopy. PMID:14978304

Gay, Grant L.; Lindhout, Darrin A.; Sykes, Brian D.

2004-01-01

215

Slow Release Of Reagent Chemicals From Gel Matrices  

NASA Technical Reports Server (NTRS)

Procedure developed for slow release of reagent chemicals into solutions. Simple and inexpensive and not subject to failure of equipment. Use of toothpaste-type tube or pump dispenser conceivably provides more controlled technique for storage and dispensation of gel matrix. Possible uses include controlled, slow release of reagents in chemical reactions, crystal growth, space-flight experiments, and preformed gel medications from packets.

Debnam, William J.; Barber, Patrick G.; Coleman, James

1988-01-01

216

Reagent Purification by Mercury Cathode Electrolysis I: A Practical Guide  

Microsoft Academic Search

Mercury cathode electrolysis has been recognized for decades as having the potential for being extremely effective for purifying aqueous solutions of various reagents. However, practical use of the method for reagent purification has been largely restricted to the preparation of purified electrolytes for electrochemical studies, for electroanalytical separations, or for polarographic analyses. Although much information on the use of the

J. W. Mitchell; C. McCrory

1980-01-01

217

IN-PLACE REGENERATION OF GAC USING FENTON'S REAGENTS  

EPA Science Inventory

This paper evaluates the feasibility of using Fenton?s reagents for in-place recovery of spent granular activated carbon (GAC). Fenton?s reagents are cycled through spent GAC to degrade sorbed chlorinated hydrocarbons with little loss of carbon capacity. Seven chlorinated compou...

218

An efficient reagent for covalent introduction of alkynes into proteins.  

PubMed

A cheap and bench-stable reagent was synthesized for direct and covalent introduction of alkynes into tyrosine of target proteins, which can be further modified based on click reaction to achieve fluorescence labelling or PEGylation. This reagent should be a generally useful toolbox for chemical biology and biomaterials. PMID:25354584

Zhang, Jie; Ma, Dejun; Du, Dawei; Xi, Zhen; Yi, Long

2014-12-21

219

Redox mediation and hydrogen-generation with bipyridinium reagents  

DOEpatents

A variety of redox mediating agents employing bipyridinium reagents and such reagents in conjunction with dispersed noble metals, such as platinium, are disclosed as coatings for substrates and electrodes. The agents may be charged by an applied voltage or by photoelectric effects or may be equilibrated with hydrogen. The agents are useful in reducing biological materials and electrolytic hydrogen production.

Wrighton, Mark S. (Winchester, MA); Bookbinder, Dana C. (East Greenwich, RI); Bruce, James A. (Somerville, MA); Dominey, Raymond N. (Pensacola, FL); Lewis, Nathan S. (Palo Alto, CA)

1984-03-27

220

Macromolecular photoaffinity labeling wth radioactive photoactivable heterobifunctional reagents  

SciTech Connect

Three new photoactivable heterobifunctional reagents which can be radioiodinated have been synthesized. One of the radioactive reagents, the N-hydroxysuccinimide ester of 4-azidosalicylic acid was coupled to concanavalin A and the lectin derivative was used for the photoaffinity labeling of the lectin receptor on the erythrocyte ghost membrane.

Ji, T.H.; Ji, I.

1982-04-01

221

(2-Naphthoxy)acetyl chloride, a simple fluorescent reagent.  

PubMed

In continuing the search for fluorescent reagents for analytical derivatization in chromatography, we found a simple chemical, (2-naphthoxy)acetyl chloride, with potential fluorophore/chromophore characteristics for the highly sensitive detection of analytes with an amino function. The reagent has an auxochrome (a substituted alkoxy moiety) attached to the fluorophoric/chromophoric naphthalene system, resulting in favorable spectrophotometric properties. The reagent can be easily prepared from (2-naphthoxy)acetic acid and has been used in organic synthesis; it is initially introduced as a fluorescent reagent to derivatise amantadine and memantine (amino pharmaceuticals) as model analytes. The resulting naphthoxy derivatives of the drugs can be analyzed at sub-microM levels by HPLC with fluorimetric detection (excitation wavelength 227 nm, emission wavelength 348 nm). Application of the reagent to the fluorimetric derivatization of important biological amines for sensitive detection can be expected. PMID:12613813

Duh, Tsai-Hui; Wu, Hsin-Lung; Kou, Hwang-Shang; Lu, Chi-Yu

2003-02-14

222

Novel polyoxometalate hybrids consisting of copper-lanthanide heterometallic/lanthanide germanotungstate fragments.  

PubMed

Three organic-inorganic hybrid copper-lanthanide heterometallic germanotungstates, {[Cu(en)(2)(H(2)O)] [Cu(3)Eu(en)(3)(OH)(3)(H(2)O)(2)](?-GeW(11)O(39))}(2)·11H(2)O (1), {[Cu(en)(2)(H(2)O)][Cu(3)Tb(en)(3)(OH)(3)(H(2)O)(2)](?-GeW(11)O(39))}(2)·11H(2)O (2) and {[Cu(en)(2)(H(2)O)][Cu(3)Dy(en)(3)(OH)(3)(H(2)O)(2)](?-GeW(11)O(39))}(2)·10H(2)O (3) and three polyoxometalate hybrids built by lanthanide-containing germanotungstates and copper-ethylendiamine complexes, Na(2)H(6)[Cu(en)(2)(H(2)O)](8){Cu(en)(2)[La(?-GeW(11)O(39))(2)](2)}·18H(2)O (4), K(4)H(2)[Cu(en)(2)(H(2)O)(2)](5)[Cu(en)(2)(H(2)O)](2)[Cu(en)(2)](2){Cu(en)(2)[Pr(?-GeW(11)O(39))(2)](2)}·16H(2)O (5) and KNa(2)H(7)[enH(2)](3)[Cu(en)(2)(H(2)O)](2)[Cu(en)(2)](2){Cu(en)(2)[Er(?-GeW(11)O(39))(2)](2)}·15H(2)O (6) (en = ethylenediamine) have been hydrothermally synthesized and structurally characterized by elemental analyses, inductively coupled plasma atomic emission spectrometry (ICP-AES) analyses, IR spectra, powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS) and single-crystal X-ray diffraction. 1-3 are essentially isomorphous and their main skeletons display the interesting dimeric motif {[Cu(3)Ln(en)(3)(OH)(3)(H(2)O)(2)](?-GeW(11)O(39))}(2)(4-), which is constructed from two {Cu(3)LnO(4)} cubane anchored monovacant [?-GeW(11)O(39)](8-) fragments through two W-O-Ln-O-W linkers. The primary backbones of 4-6 exhibit the tetrameric architecture {Cu(en)(2)[Ln(?-GeW(11)O(39))(2)](2)}(24-) built by two 1:2-type [Ln(?-GeW(11)O(39))(2)](13-) moieties and one [Cu(en)(2)](2+) bridge, albeit they are not isostructural. To our knowledge, 1-6 are rare polyoxometalate derivatives consisting of copper-lanthanide heterometallic/lanthanide germanotungstate fragments. 1 exhibits antiferromagnetic coupling interactions within the {Cu(3)EuO(4)} cubane units, while 2 and 3 display dominant ferromagnetic interactions between the Tb(III)/Dy(III) and Cu(II) cations. The room-temperature solid-state photoluminescence properties of 1-3 have been investigated. PMID:22850981

Zhao, Junwei; Shi, Dongying; Chen, Lijuan; Li, Yanzhou; Ma, Pengtao; Wang, Jingping; Niu, Jingyang

2012-09-21

223

Covalent Attachment of an Electroactive Sulfydryl Reagent in the Active Site of Cytochrome P450cam as Revealed by the Crystal  

E-print Network

Covalent Attachment of an Electroactive Sulfydryl Reagent in the Active Site of Cytochrome P450cam to cytochrome P450cam from Pseudomonas putida. The crystal structure of the modified enzyme was determined at 2 a striking positive shift in the heme redox potential of the ferrocene-containing P450cam from -380 m

Fülöp, Vilmos

224

Detection of bacterial spores with lanthanide-macrocycle binary complexes.  

PubMed

The detection of bacterial spores via dipicolinate-triggered lanthanide luminescence has been improved in terms of detection limit, stability, and susceptibility to interferents by use of lanthanide-macrocycle binary complexes. Specifically, we compared the effectiveness of Sm, Eu, Tb, and Dy complexes with the macrocycle 1,4,7,10-tetraazacyclododecane-1,7-diacetate (DO2A) to the corresponding lanthanide aquo ions. The Ln(DO2A)(+) binary complexes bind dipicolinic acid (DPA), a major constituent of bacterial spores, with greater affinity and demonstrate significant improvement in bacterial spore detection. Of the four luminescent lanthanides studied, the terbium complex exhibits the greatest dipicolinate binding affinity (100-fold greater than Tb(3+) alone, and 10-fold greater than other Ln(DO2A)(+) complexes) and highest quantum yield. Moreover, the inclusion of DO2A extends the pH range over which Tb-DPA coordination is stable, reduces the interference of calcium ions nearly 5-fold, and mitigates phosphate interference 1000-fold compared to free terbium alone. In addition, detection of Bacillus atrophaeus bacterial spores was improved by the use of Tb(DO2A)(+), yielding a 3-fold increase in the signal-to-noise ratio over Tb(3+). Out of the eight cases investigated, the Tb(DO2A)(+) binary complex is best for the detection of bacterial spores. PMID:19537757

Cable, Morgan L; Kirby, James P; Levine, Dana J; Manary, Micah J; Gray, Harry B; Ponce, Adrian

2009-07-15

225

Spectroscopic properties and design of highly luminescent lanthanide coordination complexes  

Microsoft Academic Search

In this paper recent advances in the development of efficient light conversion molecular devices (LCMD) based on lanthanide complexes are reviewed, with emphasis on the work of our group. We have adopted a strategy based upon both theoretical and experimental (synthesis and methodological) investigations. The theoretical aspects are described in terms of the well known theory of 4f–4f transitions and

G. F de Sá; O. L Malta; C de Mello Donegá; A. M Simas; R. L Longo; P. A Santa-Cruz; E. F da Silva

2000-01-01

226

Electronic structures and properties of lanthanide hexaboride nanowires  

NASA Astrophysics Data System (ADS)

The promising usage of lanthanide hexaboride nanowires as excellent electron emitter materials is generally attributed to the intrinsic low work functions of their bulk counterparts. Most analytical models for the field enhanced electron emission phenomenon adopt an underlying presumption of little or no change to the work function of the emission materials at the nanoscale. However, such a presumption is difficult to experimentally verify because current analytical models often employ empirical parameters such as the geometrically enhancement factors and the actual field emission areas are hard to determine. Herein, we report our density functional theory study of the size-dependence and element-specificity of the electronic structures and work functions of infinitely long lanthanide hexaboride nanowires constructed with n × n × ? unit cells (n = 1, 2, 3, and 4). Our modeling results reveal that the distinguished metal-like electronic properties and the low work function values of the sides of most examined nanowire systems are due to the abundant 4f and 5d states from the lanthanide metal atoms positioned at the Fermi level. These work function values are found to be weakly wire-size-dependent and element-dependent across the lanthanide series. They approach to the bulk values when their lateral wire-sizes are at or above 4-unit cell wide. The presence of abundance states at the Fermi level is found to be a common feature to rationalize the work functions of reported hexaboride systems.

Wang, Lu; Luo, Guangfu; Valencia, Daniel; Sierra Llavina, Carlos H.; Sabirianov, Renat. F.; Lu, Jing; Lu, Jun-Qiang; Mei, Wai-Ning; Li Cheung, Chin

2013-10-01

227

Study of lanthanide triflates as new curing initiators for DGEBA  

Microsoft Academic Search

A new class of cationic initiators, lanthanide triflates, has been studied in the curing of diglycidyl ether of bisphenol-A (DGEBA). The kinetics of this process has been evaluated by the isoconversional method that has been proved as an excellent tool to predict the technical parameters of this process. The thermal stability of the crosslinked materials has been studied by thermogravimetric

P. Castell; M. Galià; A. Serra; J. M. Salla; X. Ramis

2000-01-01

228

Lanthanide Lewis acid-mediated enantioselective conjugate radical additions.  

PubMed

[reaction: see text] Lanthanide triflates along with proline-derived ligands have been found to be efficient catalysts for enantioselective conjugate addition of nucleophilic radicals to enoates. N-Acyl oxazolidinones, when used as achiral additives, gave meaningful enhancements in the ees for the product. PMID:12182591

Sibi, Mukund P; Manyem, Shankar

2002-08-22

229

Modular chiral polyether podands and their lanthanide complexes  

Microsoft Academic Search

A novel series of modular chiral polyether podands derived from enantiomerically pure hydrobenzoin and binaphthol has been prepared using a NaH\\/15-crown-5 mediated Williamson ether synthesis. These new homochiral ligands form catalytically active complexes with lanthanide triflates, two of which have been characterised by X-ray diffraction.

Helen C Aspinall; Nicholas Greeves; Edward G McIver

2003-01-01

230

Separation of some lanthanides on potassium zinc hexacyanoferrate ion exchanger  

Microsoft Academic Search

Adsorption behaviour of Sm3+, Gd3+, Tb3+ and Tm3+ on potassium zinc hexacyanoferrate (PZF) was investigated. The effect of K+ and Zn2+ concentrations on the distribution coefficient was studied. The mechanism of ion exchange and possible separation of the lanthanides used are discussed.

N. Botros; S. El-Bayoumy; M. El-Garhy; S. A. Marei

1991-01-01

231

On the Suitability of Lanthanides as Actinide Analogs  

SciTech Connect

With the current level of actinide materials used in civilian power generation and the need for safe and efficient methods for the chemical separation of these species from their daughter products and for long-term storage requirements, a detailed understanding of actinide chemistry is of great importance. Due to the unique bonding properties of the f-elements, the lanthanides are commonly used as structural and chemical models for the actinides, but differences in the bonding between these 4f and 5f elements has become a question of immediate applicability to separations technology. This brief overview of actinide coordination chemistry in the Raymond group at UC Berkeley/LBNL examines the validity of using lanthanide analogs as structural models for the actinides, with particular attention paid to single crystal X-ray diffraction structures. Although lanthanides are commonly accepted as reasonable analogs for the actinides, these comparisons suggest the careful study of actinide materials independent of their lanthanide analogs to be of utmost importance to present and future efforts in nuclear industries.

Szigethy, Geza; Raymond, Kenneth N.

2008-04-11

232

On the suitability of lanthanides as actinide analogs  

SciTech Connect

With the current level of actinide materials used in civilian power generation and the need for safe and efficient methods for the chemical separation of these species from their daughter products and for long-term storage requirements, a detailed understanding of actinide chemistry is of great importance. Due to the unique bonding properties of the f-elements, the lanthanides are commonly used as structural and chemical models for the actinides, but differences in the bonding between these 4f and 5f elements has become a question of immediate applicability to separations technology. This brief overview of actinide coordination chemistry in the Raymond group at UC Berkeley/LBNL examines the validity of using lanthanide analogs as structural models for the actinides, with particular attention paid to single crystal X-ray diffraction structures. Although lanthanides are commonly accepted as reasonable analogs for the actinides, these comparisons suggest the careful study of actinide materials independent of their lanthanide analogs to be of utmost importance to present and future efforts in nuclear industries. (authors)

Raymond, Kenneth; Szigethy, Geza [Chemistry Department, University of California, Berkeley, CA, 94720-1460 (United States)

2008-07-01

233

Detection of Bacterial Spores with Lanthanide-Macrocycle Binary Complexes  

PubMed Central

The detection of bacterial spores via dipicolinate-triggered lanthanide luminescence has been improved in terms of detection limit, stability, and susceptibility to interferents by use of lanthanide-macrocycle binary complexes. Specifically, we compared the effectiveness of Sm, Eu, Tb and Dy complexes with the macrocycle 1,4,7,10-tetraazacyclododecane-1,7-diacetate (DO2A) to the corresponding lanthanide aquo ions. The Ln(DO2A)+ binary complexes bind dipicolinic acid (DPA), a major constituent of bacterial spores, with greater affinity and demonstrate significant improvement in bacterial spore detection. Of the four luminescent lanthanides studied, the terbium complex exhibits the greatest dipicolinate binding affinity (100-fold greater than Tb3+ alone, and 10-fold greater than other Ln(DO2A)+ complexes) and highest quantum yield. Moreover, the inclusion of DO2A extends the pH range over which Tb-DPA coordination is stable, reduces the interference of calcium ions nearly 5-fold, and mitigates phosphate interference 1000-fold compared to free terbium alone. In addition, detection of Bacillus atrophaeus bacterial spores was improved by the use of Tb(DO2A)+, yielding a 3-fold increase in the signal-to-noise ratio over Tb3+. Out of the eight cases investigated, the Tb(DO2A)+ binary complex is best for the detection of bacterial spores. PMID:19537757

Cable, Morgan L.; Kirby, James P.; Levine, Dana J.; Manary, Micah J.; Gray, Harry B.; Ponce, Adrian

2009-01-01

234

Immunomicrospheres - Reagents for cell labeling and separation  

NASA Technical Reports Server (NTRS)

Immunomicrospheres are specially designed microscopic particles that have antibodies or similar molecules chemically bound to their surfaces. The antibody-coated microspheres react in a highly specific way with target cells, viruses, or other antigenic agents. Immunomicrospheres may be synthesized so that they incorporate compounds that are highly radioactive, intensely fluorescent, magnetic, electron opaque, highly colored, or pharmacologically active. These various types of microspheres may be coated with pure, highly specific monoclonal antibodies obtained by the new hybridoma cell cloning techniques or with conventional antibody preparations. Some of the many present and potential applications for these new reagents are (1) new types of radioimmune or immunofluorescent assays, (2) improved fluorescence microscopy, (3) separation of cells on the basis of the fluorescent, electrophoretic, or magnetic properties of bound immunomicrospheres, (4) markers for use in several types of electron or standard light microscopy, and (5) delivery of lethal compouds to specific undesirable living cells. The combination of the various new types of synthetic microspheres and the newly available homogeneous antibodies offers new opportunities in research, diagnosis, and therapy.

Rembaum, A.; Dreyer, W. J.

1980-01-01

235

Emulsified coal oils as flotation reagents  

SciTech Connect

Investigations were conducted with the goal of preparing coal oils for use in coal flotation by preliminary emulsification. When added to the slurry, this oil is rapidly and uniformly distributed over the surface of the coal particles. The emulsification was conducted by mechanical dispersion in a laboratory agitator. (Under industrial conditions this process may be conducted in a centrifugal pump). A neutralized solution of acid tar (a waste from the sulfuric acid purification of crude benzol) was used as the emulsifier and emulsion stabilizer. The concentration of sulfonic acids was about 48%. Stable homogeneous emulsions were obtained at a concentration of oil up to 20% and neutralized tar of 0.2%. The size of the oil droplets in the emulsions was 2-10 microns. Experimental testing was conducted on a Mekhanobr laboratory flotation machine with a chamber 1 litter in volume. Unemulsified and emulsified coal oils from the tar refining division of the Makeevka Coke Works were investigated; screenings from the charge of the Yasinovka Coke Works (the below-0.5-mm size class) were floated. As a comparison experiments with the traditional kerosene reagent were conducted. In the experiments with anthracene oil, pitch distillates and kerosene, T-66 frothing agent was added at 140 g/ton of sludge; during the work with wash oil and naphthalene exudates T-66 was not added, assuming that the water-soluble phenols and bases contained in these oils have adequate frothing capacity. 5 references, 2 figures.

Selyanko, I.T.; Belov, K.A.; Karnozhitskii, P.V.; Ivashchenko, V.A.

1983-01-01

236

Bispyrene/Surfactant-assembly-based fluorescent sensor array for discriminating lanthanide ions in aqueous solution.  

PubMed

Lanthanides are valuable nonrenewable resources and widely used in a variety of industries. Detection and identification of lanthanide ions are in high demand but challenging because of the similarity among lanthanide ions. In the present work, a fluorescent sensor array of three cationic bispyrene derivatives mixed with anionic surfactant assemblies was developed. The sensor array exhibits cross-reactive responses to lanthanide ions when tested in aqueous solution. The combination of fluorescence variations at both monomer and excimer emission of each of the bispyrene sensor elements provides a six-signal recognition pattern for lanthanide ions. Principle component analysis illustrates that the sensor array could at least identify 6 of the 14 similar lanthanide ions including La(3+), Pr(3+), Nd(3+), Eu(3+), Ho(3+), and Er(3+). UV-vis absorption measurements rule out the possibility of binding lanthanides with fluorophores. Fluorescence titration experiments in both cationic and neutral surfactant aqueous solutions reveal that the three fluorophores show slight fluorescence responses to the lanthanide ions, indicating that electrostatic attraction between lanthanide ions and anionic surfactant plays an important role in the sensing behavior of the sensor array. Control experiments with divalent metal ions find no cross-reactive responses, suggesting that the stronger electrostatic interaction with trivalent lanthanide ions is responsible for the multiple fluorescence responses. PMID:25188720

Wang, Shihuai; Ding, Liping; Fan, Junmei; Wang, Zhongxiu; Fang, Yu

2014-09-24

237

Enhancement of anion binding in lanthanide optical sensors.  

PubMed

In the design of molecular sensors, researchers exploit binding interactions that are usually defined in terms of topology and charge complementarity. The formation of complementary arrays of highly cooperative, noncovalent bonding networks facilitates protein-ligand binding, leading to motifs such as the "lock-and-key". Synthetic molecular sensors often employ metal complexes as key design elements as a way to construct a binding site with the desired shape and charge to achieve target selectivity. In transition metal complexes, coordination number, structure and ligand dynamics are governed primarily by a combination of inner-sphere covalent and outer-sphere noncovalent interactions. These interactions provide a rich variable space that researchers can use to tune structure, stability, and dynamics. In contrast, lanthanide(III)-ligand complex formation and ligand-exchange dynamics are dominated by reversible electrostatic and steric interactions, because the unfilled f shell is shielded by the larger, filled d shell. Luminescent lanthanides such as terbium, europium, dysprosium, and samarium display many photophysical properties that make them excellent candidates for molecular sensor applications. Complexes of lanthanide ions act as receptors that exhibit a detectable change in metal-based luminescence upon binding of an anion. In our work on sensors for detection of dipicolinate, the unique biomarker of bacterial spores, we discovered that the incorporation of an ancillary ligand (AL) can enhance binding constants of target anions to lanthanide ions by as much as two orders of magnitude. In this Account, we show that selected ALs in lanthanide/anion systems greatly improve sensor performance for medical, planetary science, and biodefense applications. We suggest that the observed anion binding enhancement could result from an AL-induced increase in positive charge at the lanthanide ion binding site. This effect depends on lanthanide polarizability, which can be established from the ionization energy of Ln(3+) ? Ln(4+). These results account for the order Tb(3+) > Dy(3+) > Eu(3+) ? Sm(3+). As with many lanthanide properties, ranging from hydration enthalpy to vaporization energy, this AL-induced enhancement shows a large discrepancy between Tb(3+) and Eu(3+) despite their similarity in size, a phenomenon known as the "gadolinium break". This discrepancy, based on the unusual stabilities of the Eu(2+) and Tb(4+) oxidation states, results from the half-shell effect, as both of these ions have half-filled 4f-shells. The high polarizability of Tb(3+) explains the extraordinarily large increase in the binding affinity of anions for terbium compared to other lanthanides. We recommend that researchers consider this AL-induced enhancement when designing lanthanide-macrocycle optical sensors. Ancillary ligands also can reduce the impact of interfering species such as phosphate commonly found in environmental and physiological samples. PMID:24032446

Cable, Morgan L; Kirby, James P; Gray, Harry B; Ponce, Adrian

2013-11-19

238

Spectroscopic studies on the lanthanide sensitized luminescence and chemiluminescence properties of fluoroquinolone with different structure  

NASA Astrophysics Data System (ADS)

Lanthanide sensitized luminescence and chemiluminescence (CL) are of great importance because of the unique spectral properties, such as long lifetime, large Stokes shifts, and narrow emission bands characteristic to lanthanide ions (Ln 3+). With the fluoroquinolone (FQ) compounds including enoxacin (ENX), norfloxacin (NFLX), lomefloxacin (LMFX), fleroxacin (FLRX), ofloxacin (OFLX), rufloxacin (RFX), gatifloxacin (GFLX) and sparfloxacin (SPFX), the luminescence and CL properties of Tb 3+-FQ and Eu 3+-FQ complexes have been investigated in this contribution. Ce 4+-SO 32- in acidic conditions was taken as the CL system and sensitized CL intensities of Tb 3+-FQ and Eu 3+-FQ complexes were determined by flow-injection analysis. The luminescence and CL spectra of Tb 3+-FQ complexes show characteristic peaks of Tb 3+ at 490 nm, 545 nm, 585 nm and 620 nm. Complexes of Tb 3+-ENX, Tb 3+-NFLX, Tb 3+-LMFX and Tb 3+-FLRX display relatively strong emission intensity compared with Tb 3+-OFLX, Tb 3+-RFX, Tb 3+-GFLX and Tb 3+-SPFX. Quite weak peaks with unique characters of Eu 3+ at 590 nm and 617 nm appear in the luminescence and CL spectra of Eu 3+-ENX, but no notable sensitized luminescence and CL of Eu 3+ could be observed when Eu 3+ is added into other FQ. The distinct differences on emission intensity of Tb 3+-FQ and Eu 3+-FQ might originate from the different energy gap between the triplet levels of FQ and the excited levels of the Ln 3+. The different sensitized luminescence and CL signals among Tb 3+-FQ complexes could be attributed to different optical properties and substituents of these FQ compounds. The detailed mechanism involved in the luminescence and CL properties of Tb 3+-FQ and Eu 3+-FQ complexes has been investigated by analyzing the luminescence and CL spectra, quantum yields, and theoretical calculation results.

Sun, Chunyan; Ping, Hong; Zhang, Minwei; Li, Hongkun; Guan, Fengrui

2011-11-01

239

Spectroscopic studies on the lanthanide sensitized luminescence and chemiluminescence properties of fluoroquinolone with different structure.  

PubMed

Lanthanide sensitized luminescence and chemiluminescence (CL) are of great importance because of the unique spectral properties, such as long lifetime, large Stokes shifts, and narrow emission bands characteristic to lanthanide ions (Ln(3+)). With the fluoroquinolone (FQ) compounds including enoxacin (ENX), norfloxacin (NFLX), lomefloxacin (LMFX), fleroxacin (FLRX), ofloxacin (OFLX), rufloxacin (RFX), gatifloxacin (GFLX) and sparfloxacin (SPFX), the luminescence and CL properties of Tb(3+)-FQ and Eu(3+)-FQ complexes have been investigated in this contribution. Ce(4+)-SO(3)(2-) in acidic conditions was taken as the CL system and sensitized CL intensities of Tb(3+)-FQ and Eu(3+)-FQ complexes were determined by flow-injection analysis. The luminescence and CL spectra of Tb(3+)-FQ complexes show characteristic peaks of Tb(3+) at 490 nm, 545 nm, 585 nm and 620 nm. Complexes of Tb(3+)-ENX, Tb(3+)-NFLX, Tb(3+)-LMFX and Tb(3+)-FLRX display relatively strong emission intensity compared with Tb(3+)-OFLX, Tb(3+)-RFX, Tb(3+)-GFLX and Tb(3+)-SPFX. Quite weak peaks with unique characters of Eu(3+) at 590 nm and 617 nm appear in the luminescence and CL spectra of Eu(3+)-ENX, but no notable sensitized luminescence and CL of Eu(3+) could be observed when Eu(3+) is added into other FQ. The distinct differences on emission intensity of Tb(3+)-FQ and Eu(3+)-FQ might originate from the different energy gap between the triplet levels of FQ and the excited levels of the Ln(3+). The different sensitized luminescence and CL signals among Tb(3+)-FQ complexes could be attributed to different optical properties and substituents of these FQ compounds. The detailed mechanism involved in the luminescence and CL properties of Tb(3+)-FQ and Eu(3+)-FQ complexes has been investigated by analyzing the luminescence and CL spectra, quantum yields, and theoretical calculation results. PMID:21821467

Sun, Chunyan; Ping, Hong; Zhang, Minwei; Li, Hongkun; Guan, Fengrui

2011-11-01

240

The variable reagent blank: protein determination as a model.  

PubMed

Three total protein assays were analyzed to determine the extent of deviation encountered when a constant measured reagent blank is compared to a continuously decreasing true reagent blank. This blank effect owes its regressive nature to the consumption of the active reagent ingredient by the protein reactive species, variably and sometimes, with certain reactants, nonlinearly in the presence of increasing protein concentrations. However, the blank effect of interest here is apparent only when the reagent and the reagent-protein complex present overlapping spectra and therefore absorb at the wavelength of measurement. Thus it was found that while the biuret and the Coomassie brilliant blue assays produced pronounced differences in the variable true reagent blanks, the Folin-Ciocalteau reaction did not develop a deviation from the true blank since the reagent blank does not absorb to any extent at the assay wavelength. In this manner, the latter procedure could serve as a marker against which the former two blank reactions can be shown to display relatively excessive deviations. PMID:4067517

Bozimowski, D; Artiss, J D; Zak, B

1985-10-01

241

Methyltrihydroborate complexes of the lanthanides and actinides  

SciTech Connect

Reaction of MC1/sub 4/ (M = Zr, Hf, U, Th, Np) with LiBH/sub 3/CH/sub 3/ in chlorobenzene produces volatile, hexane-soluble M(BH/sub 3/CH/sub 3/)/sub 4/. Crystal structures are monomeric, tetrahedral species. Lewis base adducts prepared include U(BH/sub 3/CH/sub 3/)/sub 4/.THT, Th(BH/sub 3/CH/sub 3/)/sub 4/.L (L = THF (tetrahydrofuran), THT (tetrahydrothiophene), SMe/sub 2/, OMe/sub 2/), U(BH/sub 3/CH/sub 3/)/sub 4/.2L (L = THF, pyridine, NH/sub 3/), Th(BH/sub 3/CH/sub 3/)/sub 4/.2L (L = THF, THT, py, NH/sub 3/), M(BH/sub 3/CH/sub 3/)/sub 4/.L-L (M = U, Th; L-L = dme (1,2-dimethoxyethane), bmte (bis(1,2-methylthio)ethane), tmed (N,N,N',N'-tetramethylethylenediamine), dmpe (1,2-dimethylphosphinoethane)) and Th(BH/sub 3/CH/sub 3/)/sub 4/.1/2 OEt/sub 2/. Reaction of MC1/sub 3/ (M = Ho, Yb, Lu) with LiBH/sub 3/CH/sub 3/ in diethyl ether produces volatile, toluene-soluble M(BH/sub 3/CH/sub 3/)/sub 3/.OEt/sub 2/. Other Lewis base adducts prepared from M(BH/sub 3/CH/sub 3/)/sub 3/.OEt/sub 2/ include Ho(BH/sub 3/CH/sub 3/)/sub 3/.L (L = THT, THF, py), Ho(BH/sub 3/CH/sub 3/)/sub 3/.2L (L = THT, THF, py), Ho(BH/sub 3/CH/sub 3/)/sub 3/.tmed, Ho(BH/sub 3/CH/sub 3/)/sub 3/.3/2 L-L (L-L = dmpe, bmte), Yb(BH/sub 3/CH/sub 3/)/sub 3/.3/2 dmpe, Yb(BH/sub 3/Ch/sub 3/).L (L = THF, dme), Yb(BH/sub 3/CH/sub 3/)/sub 3/.2THF, and Lu(BH/sub 3/CH/sub 3/)/sub 3/.THF. By structural criteria, the bonding in actinide and lanthanide methyltrihydroborate complexes is primarily ionic in character even though they display covalent-like physical properties. Spectroscopic measurements indicate that there is some degree of covalent bonding in U(BH/sub 3/CH/sub 3/)/sub 4/.

Shinomoto, R.S.

1984-11-01

242

21 CFR 866.3720 - Streptococcus spp. exo-enzyme reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Streptococcus spp. exo-enzyme reagents. 866.3720 Section 866.3720 Food and Drugs...Serological Reagents § 866.3720 Streptococcus spp. exo-enzyme reagents. (a) Identification. Streptococcus...

2010-04-01

243

21 CFR 866.3720 - Streptococcus spp. exo-enzyme reagents.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Streptococcus spp. exo-enzyme reagents. 866.3720 Section 866.3720 Food and Drugs...Serological Reagents § 866.3720 Streptococcus spp. exo-enzyme reagents. (a) Identification. Streptococcus...

2011-04-01

244

21 CFR 866.3720 - Streptococcus spp. exo-enzyme reagents.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Streptococcus spp. exo-enzyme reagents. 866.3720 Section 866.3720 Food and Drugs...Serological Reagents § 866.3720 Streptococcus spp. exo-enzyme reagents. (a) Identification. Streptococcus...

2013-04-01

245

21 CFR 866.3720 - Streptococcus spp. exo-enzyme reagents.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Streptococcus spp. exo-enzyme reagents. 866.3720 Section 866.3720 Food and Drugs...Serological Reagents § 866.3720 Streptococcus spp. exo-enzyme reagents. (a) Identification. Streptococcus...

2012-04-01

246

21 CFR 866.3830 - Treponema pallidum tre-ponemal test reagents.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 false Treponema pallidum tre-ponemal test reagents...Serological Reagents § 866.3830 Treponema pallidum tre-ponemal test reagents. (a) Identification. Treponema pallidum treponemal test...

2010-04-01

247

21 CFR 866.3820 - Treponema pallidum non-treponemal test reagents.  

Code of Federal Regulations, 2012 CFR

... 2012-04-01 false Treponema pallidum non-treponemal test reagents...Serological Reagents § 866.3820 Treponema pallidum non-treponemal test reagents. (a) Identification. Treponema pallidum nontreponemal...

2012-04-01

248

21 CFR 866.3830 - Treponema pallidum tre-ponemal test reagents.  

... 2014-04-01 false Treponema pallidum tre-ponemal test reagents...Serological Reagents § 866.3830 Treponema pallidum tre-ponemal test reagents. (a) Identification. Treponema pallidum treponemal test...

2014-04-01

249

21 CFR 866.3820 - Treponema pallidum non-treponemal test reagents.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false Treponema pallidum non-treponemal test reagents...Serological Reagents § 866.3820 Treponema pallidum non-treponemal test reagents. (a) Identification. Treponema pallidum nontreponemal...

2013-04-01

250

21 CFR 866.3820 - Treponema pallidum non-treponemal test reagents.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 false Treponema pallidum non-treponemal test reagents...Serological Reagents § 866.3820 Treponema pallidum non-treponemal test reagents. (a) Identification. Treponema pallidum nontreponemal...

2011-04-01

251

Lanthanide speciation in potential SANEX and GANEX actinide/lanthanide separations using tetra-N-donor extractants.  

PubMed

Lanthanide(III) complexes with N-donor extractants, which exhibit the potential for the separation of minor actinides from lanthanides in the management of spent nuclear fuel, have been directly synthesized and characterized in both solution and solid states. Crystal structures of the Pr(3+), Eu(3+), Tb(3+), and Yb(3+) complexes of 2,9-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)-1,10-phenanthroline (CyMe4-BTPhen) and the Pr(3+), Eu(3+), and Tb(3+) complexes of 6,6'-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)-2,2'-bypyridine (CyMe4-BTBP) were obtained. The majority of these structures displayed coordination of two of the tetra-N-donor ligands to each Ln(3+) ion, even when in some cases the complexations were performed with equimolar amounts of lanthanide and N-donor ligand. The structures showed that generally the lighter lanthanides had their coordination spheres completed by a bidentate nitrate ion, giving a 2+ charged complex cation, whereas the structures of the heavier lanthanides displayed tricationic complex species with a single water molecule completing their coordination environments. Electronic absorption spectroscopic titrations showed formation of the 1:2 Ln(3+)/L(N4-donor) species (Ln = Pr(3+), Eu(3+), Tb(3+)) in methanol when the N-donor ligand was in excess. When the Ln(3+) ion was in excess, evidence for formation of a 1:1 Ln(3+)/L(N4-donor) complex species was observed. Luminescent lifetime studies of mixtures of Eu(3+) with excess CyMe4-BTBP and CyMe4-BTPhen in methanol indicated that the nitrate-coordinated species is dominant in solution. X-ray absorption spectra of Eu(3+) and Tb(3+) species, formed by extraction from an acidic aqueous phase into an organic solution consisting of excess N-donor extractant in pure cyclohexanone or 30% tri-n-butyl phosphate (TBP) in cyclohexanone, were obtained. The presence of TBP in the organic phase did not alter lanthanide speciation. Extended X-ray absorption fine structure data from these spectra were fitted using chemical models established by crystallography and solution spectroscopy and showed the dominant lanthanide species in the bulk organic phase was a 1:2 Ln(3+)/L(N-donor) species. PMID:23438021

Whittaker, Daniel M; Griffiths, Tamara L; Helliwell, Madeleine; Swinburne, Adam N; Natrajan, Louise S; Lewis, Frank W; Harwood, Laurence M; Parry, Stephen A; Sharrad, Clint A

2013-04-01

252

High-Load, Hybrid Si-ROMP Reagents  

PubMed Central

The combination of norbornenyl-tagged (Nb-tagged) silica particles and functionalized Nb-tagged monomers for the generation of hybrid Si-ROMP reagents and scavengers is reported. Specifically Si-ROMP-derived bis-acid chloride, dichlorotriazine and triphenylphosphine scavenger/reagents have been grafted from the surface of silica particles utilizating surface-initiated, ring-opening metathesis polymerization (ROMP). These hybridpolymeric materials combine the physical properties of current immobilized silica reagents and represent a key advancement in load by merging the inherent tunable properties of the ROMP-derived oligomers with silica supports for application in parallel synthesis. PMID:21128690

Rolfe, Alan; Loh, Joanna K.; Maity, Pradip K.; Hanson, Paul R.

2011-01-01

253

Polymeric microspheres as protein transduction reagents.  

PubMed

Discovering the function of an unknown protein, particularly one with neither structural nor functional correlates, is a daunting task. Interaction analyses determine binding partners, whereas DNA transfection, either transient or stable, leads to intracellular expression, though not necessarily at physiologically relevant levels. In theory, direct intracellular protein delivery (protein transduction) provides a conceptually simpler alternative, but in practice the approach is problematic. Domains such as HIV TAT protein are valuable, but their effectiveness is protein specific. Similarly, the delivery of intact proteins via endocytic pathways (e.g. using liposomes) is problematic for functional analysis because of the potential for protein degradation in the endosomes/lysosomes. Consequently, recent reports that microspheres can deliver bio-cargoes into cells via a non-endocytic, energy-independent pathway offer an exciting and promising alternative for in vitro delivery of functional protein. In order for such promise to be fully exploited, microspheres are required that (i) are stably linked to proteins, (ii) can deliver those proteins with good efficiency, (iii) release functional protein once inside the cells, and (iv) permit concomitant tracking. Herein, we report the application of microspheres to successfully address all of these criteria simultaneously, for the first time. After cellular uptake, protein release was autocatalyzed by the reducing cytoplasmic environment. Outside of cells, the covalent microsphere-protein linkage was stable for ?90 h at 37 °C. Using conservative methods of estimation, 74.3% ± 5.6% of cells were shown to take up these microspheres after 24 h of incubation, with the whole process of delivery and intracellular protein release occurring within 36 h. Intended for in vitro functional protein research, this approach will enable study of the consequences of protein delivery at physiologically relevant levels, without recourse to nucleic acids, and offers a useful alternative to commercial protein transfection reagents such as Chariot™. We also provide clear immunostaining evidence to resolve residual controversy surrounding FACS-based assessment of microsphere uptake. PMID:24692642

Nagel, David; Behrendt, Jonathan M; Chimonides, Gwen F; Torr, Elizabeth E; Devitt, Andrew; Sutherland, Andrew J; Hine, Anna V

2014-06-01

254

21 CFR 866.3350 - Leptospira spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

... spp. from cultured isolates derived from clinical specimens. Additionally, some of these antisera are conjugated with a fluorescent dye (immunofluorescent reagents) and used to identify Leptospira spp. directly from clinical specimens. The...

2010-04-01

255

21 CFR 866.3370 - Mycobacterium tuberculosis immunofluorescent reagents.  

Code of Federal Regulations, 2010 CFR

...Identification. Mycobacterium tuberculosis immunofluorescent reagents are devices that consist of antisera conjugated with a fluorescent dye used to identify Mycobacterium tuberculosis directly from clinical specimens. The identification aids in the...

2010-04-01

256

21 CFR 866.3140 - Corynebacterium spp. serological reagents.  

Code of Federal Regulations, 2011 CFR

...a) Identification. Corynebacterium spp. serological reagents are devices that consist of antisera conjugated with a fluorescent dye used to identify Corynebacterium spp. from clinical specimens. The identification aids in the diagnosis of...

2011-04-01

257

21 CFR 866.3140 - Corynebacterium spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...a) Identification. Corynebacterium spp. serological reagents are devices that consist of antisera conjugated with a fluorescent dye used to identify Corynebacterium spp. from clinical specimens. The identification aids in the diagnosis of...

2010-04-01

258

21 CFR 866.3120 - Chlamydia serological reagents.  

Code of Federal Regulations, 2010 CFR

...identify antibodies to chlamydia in serum. Additionally, some of these reagents consist of chlamydia antisera conjugated with a fluorescent dye used to identify chlamydia directly from clinical specimens or cultured isolates derived from clinical...

2010-04-01

259

40 CFR 792.83 - Reagents and solutions.  

Code of Federal Regulations, 2012 CFR

...Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED...CONTROL ACT (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 792...reagents and solutions in the laboratory areas shall be labeled to...

2012-07-01

260

40 CFR 792.83 - Reagents and solutions.  

Code of Federal Regulations, 2010 CFR

...Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED...CONTROL ACT (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 792...reagents and solutions in the laboratory areas shall be labeled to...

2010-07-01

261

40 CFR 792.83 - Reagents and solutions.  

Code of Federal Regulations, 2013 CFR

...Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED...CONTROL ACT (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 792...reagents and solutions in the laboratory areas shall be labeled to...

2013-07-01

262

40 CFR 792.83 - Reagents and solutions.  

...Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED...CONTROL ACT (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 792...reagents and solutions in the laboratory areas shall be labeled to...

2014-07-01

263

40 CFR 792.83 - Reagents and solutions.  

Code of Federal Regulations, 2011 CFR

...Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED...CONTROL ACT (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 792...reagents and solutions in the laboratory areas shall be labeled to...

2011-07-01

264

21 CFR 866.3630 - Serratia spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...serological reagents. 866.3630 Section 866.3630 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...are occasionally associated with gastroenteritis (food poisoning) and wound infections. (b)...

2010-04-01

265

21 CFR 866.3035 - Arizona spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...serological reagents. 866.3035 Section 866.3035 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...microorganisms. Arizona spp. can cause gastroenteritis (food poisoning) and sepsis (blood poisoning). (b)...

2010-04-01

266

21 CFR 866.3630 - Serratia spp. serological reagents.  

Code of Federal Regulations, 2011 CFR

...serological reagents. 866.3630 Section 866.3630 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...are occasionally associated with gastroenteritis (food poisoning) and wound infections. (b)...

2011-04-01

267

21 CFR 866.3035 - Arizona spp. serological reagents.  

Code of Federal Regulations, 2011 CFR

...serological reagents. 866.3035 Section 866.3035 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...microorganisms. Arizona spp. can cause gastroenteritis (food poisoning) and sepsis (blood poisoning). (b)...

2011-04-01

268

21 CFR 866.3330 - Influenza virus serological reagents.  

Code of Federal Regulations, 2011 CFR

Influenza virus serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies to influenza in serum. The identification aids in the diagnosis of influenza (flu) and provides epidemiological information on...

2011-04-01

269

21 CFR 866.3330 - Influenza virus serological reagents.  

Code of Federal Regulations, 2010 CFR

Influenza virus serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies to influenza in serum. The identification aids in the diagnosis of influenza (flu) and provides epidemiological information on...

2010-04-01

270

Dynamic tests for actinide/lanthanide separation by CMPO solvent in fluorinated diluents  

SciTech Connect

Actinide and lanthanide extraction by new solvent: 0.2 M phenyl-octyl-N,N-diiso-butylcarbamoyl-phosphine oxide (CMPO) + 30% TBP + formal of octafluoro-pentanol was studied. A dynamic test with this solvent was performed. It was shown that americium and lanthanides are effectively extracted from PUREX process raffinate. The separation of americium from light lanthanides was confirmed in the modified SETFICS flowsheet with this new solvent. (authors)

Tkachenko, L.; Babain, V.; Alyapyshev, M.; Vizniy, A.; Il'in, A. [V. G. Khlopin Radium Institute, 2nd Murinskiy Ave 28., St. Petersburg 194021 (Russian Federation); Shadrin, A. [A.A. Bochvar High-technology Research Institute of Inorganic Materials, 5-a, Rogova str., Moscow 123098 (Russian Federation)

2013-07-01

271

Recent progress in lanthanide-catalyzed organic reactions in protic media  

Microsoft Academic Search

Lanthanide triflates are stable in water. It is possible for lanthanides to undergo many organic reactions in environmentally\\u000a friendly solvents. This makes lanthanides very promising in the field of green chemistry. This review describes the recent\\u000a development of the lanthanidecatalyzed organic reactions in protic solvents. Those reactions include Diels-Alder, Aldol, Allylation,\\u000a acetalization, pericyclization, radical reactions as well as some newlydeveloped

Luo Sanzhong; Zhang Baolian; Xian Ming; Adam JaÑczuk; Xie Wenhua; Cheng Jinpei; Peng George Wang

2001-01-01

272

Nanochemistry and supramolecular chemistry of actinides and lanthanides: Problems and prospects  

Microsoft Academic Search

The possibility of using unique properties of lanthanides in the nanotechnology is demonstrated. The origination of linear\\u000a and nonlinear optical properties of lanthanide compounds with phthalocyanines, porphyrins, naphthalocyanines, and their analogs\\u000a in solutions and condensed state and the prospects of obtaining novel materials on their basis are discussed. Based on the\\u000a electronic structure and properties of lanthanides and their compounds,

A. Yu. Tsivadze; G. V. Ionova; V. K. Mikhalko

2010-01-01

273

Extraction of trivalent lanthanides and actinides by ``CMPO-like`` calixarenes  

SciTech Connect

Extractive properties of calix[4]arenes bearing carbamoylmethylphosphine oxide moieties on their upper rim toward trivalent lanthanide and actinide cations were investigated. The study revealed that these molecules selectively extract light lanthanides and actinides from heavy lanthanides. All parameters present in the extraction system were varied to determine the origin of the selectivity. It was found that this selectivity requires a calix[4]arene platform and acetamidophosphine oxide groups containing phenyl substituents on the four phosphorus atoms.

Delmau, L.H.; Simon, N. [CEA Cadarache, St. Paul lez Durance (France)] [CEA Cadarache, St. Paul lez Durance (France); Schwing-Weill, M.J. [ECPM, Strasbourg (France)] [and others] [ECPM, Strasbourg (France); and others

1999-04-01

274

Minimization of Eutectic Salt Waste from Pyroprocessing by Oxidative Precipitation of Lanthanides  

Microsoft Academic Search

A lab-scale lanthanide precipitation apparatus, which has a 4 kg\\/batch size, was installed and tested. By using this lab-scale apparatus, cooxidative precipitation experiments of lanthanides were carried out. As lanthanides, 8 rare-earth elements (Y, La, Ce, Pr, Nd, Sm, Eu, and Gd) were used. By a reaction with oxygen, La, Pr, Nd, Sm, Eu, and Gd were converted to their

Yung-Zun CHO; Gil-Ho PARK; Hee-Chul YANG; Dae-Seok HAN; Han-Soo LEE; In-Tae KIM

2009-01-01

275

Transport of lanthanides in milk into suckling rats.  

PubMed

The aim of this paper was to examine the transport of lanthanides in milk of contaminated rats into their sucklings and the retention of lanthanides in the sucklings. The research involved 55 female Wistar rats contaminated in the period of lactation and their offspring (400 infant rats). The study showed that in the period of lactation the transport in milk from the mother to the offspring of the lanthanide radionuclides under examination (144Ce, 147Nd, 152Sm, 155Eu and 160Tb) increased with their mass numbers: CE < Nd < Sm < Eu < Tb, and varied from 0.01% for 144Ce to 17.7% for 160Tb of the administered dose per litter. It was demonstrated that lanthanides were not absorbed from the digestive tract of sucklings because they were not detected beyond its area. Because of its highest concentration in milk 160Tb was chosen for further investigation of the kinetics of transport in individual segments of the digestive tract. The model for determining the function of lanthanide retention in separate parts of the digestive tract of sucklings and the half life of effective accumulation and elimination of 160Tb in the whole organism as well as in individual segments of the digestive tract are presented. Terbium-160 accumulation in sucklings increased whereas its elimination decreased with the age of the infant. No significant differences in 160Tb specific activity in stomach, and small and large intestines were observed in sucklings one to 21 days old. Biological half lives for retention of the contaminated milk were as follow: 0.25 +/- 0.021 per day for the stomach, 0.92 +/- 0.12 per day for the small intestine and 5.03 +/- 0.22 per day for the large intestine. The data obtained can be used in the evaluation of the doses absorbed from 160Tb and from other lanthanide radionuclides that are nonabsorbable from the digestive tract, as well as in estimation of the radiation risk to the offspring of mothers contaminated in the period of lactation. PMID:9050340

Marciniak, M; Cha?, J; Baltrukiewicz, Z

1996-12-01

276

Standard Materials for Microbeam Analysis of Lanthanides and Actinides  

NASA Astrophysics Data System (ADS)

Traces of Th and U in naturally-occuring minerals monazite, xenotime and zircon are used for dating host rocks. Natural variations of actinide concentrations in some rock formations are well documented. Microbeam techniques perform dating in-situ where grains of indicator minerals are left intact in thin sections. Separated individual grains of these minerals are also routinely dated by Pb-isotope mass spectrometry. Ideal calibration materials will be compatible with multiple techniques. Quantitative analysis of low levels of lanthanides (REE), U, Th and Pb found in natural minerals requires standards containing similar concentrations of these elements. The ideal low-level standard suite will have materials with each REE cation present below 5%, similar to natural rare-earth phosphate minerals. In contrast, REE orthophosphates LnPO4 have cation concentrations from 59 to 64%, and ultraphosphates LnP5O14 from 27% to 32%. The concentrations of U and Pb must also be in the 1% range in the host REE phosphate. There are two competing limits to the synthesis of crystals with multiple cations in the REE sites. The crystal structure limits potential cation mixtures to selections within groups (La,Ce, Pr, Nd, Sm, Eu), (Gd, Tb, Dy, Ho), and (Er, Tm,Yb, Lu, Y). Complex L X-ray spectra limit the use of contiguous REE in a single material. There are two general synthetic routes for the preparation of lanthanide/actinide standard materials for beam analysis and dating. Lanthanide orthophosphates (LnPO4) are crystallized from lead-free heterogeneous fluxes; oligomers (metaphosphates LnP3O9 and ultraphosphates LnP5O14) are formed by condensation of phosphoric acid in the presence of cations. All of these trivalent lanthanide phosphate crystal structures are hosts for Th+4 and U+4, and in synthetic materals, Ca+2 is used for charge compensation. Our work focuses on the preparation of mixed-cation lanthanide metaphosphates and ultraphosphates. The solvent (essentially P2O5) provides redox conditions that favour Ce+3, Th+4, and U+4 instead of higher oxidation states. The absence of any cations other than those deliberately added permits positive control of cation mixtures in starting materials. The synthetic pathway—condensation of POx units--provides ideal conditions for the homogeneous distribution of cations including those with different charges. We present the results of synthesis, elemental analysis and imaging by XRF and SEM-EDX for mixed lanthanide-actinide phosphate materials.

Ellis, I.; Gorton, M.; Rucklidge, J. C.

2010-12-01

277

Chemical oxidation treatment of petroleum contaminated soil using Fenton's reagent  

Microsoft Academic Search

Fenton's reagent, a strong oxidant, was evaluated for suitability to treat soils contaminated with 2?methylnaphthalene (an aromatic compound), n?hexdecane (an aliphatic compound) and diesel fuel (a complicated hydrocarbon mixture). Laboratory?scale results show that Fenton's reagent reacts rapidly with these materials in soil, and will completely mineralize them if enough hydrogen peroxide is added. The effectiveness of the reaction at neutral

Chien T. Chen; Anthony N. Tafuri; Maqsud Rahman; Mary B. Foerst

1998-01-01

278

Comparison in accumulation of lanthanide elements among three Brassicaceae plant sprouts.  

PubMed

Three kinds of sprouts in the Brassicaceae family of plants, namely, pink kale, radish and mustard were evaluated for the possibility of phytoremediation of lanthanides. The mustard sprout more efficiently accumulated lanthanides (e.g. 0.26 nmol La/g) than other Brassicaceae family plant sprouts (0.16 nmol La/g in the radish), however the radish sprout showed the fastest growth among three sprouts. Faster growth compensated for less efficiency in lanthanide accumulation (28 pmol La in the radish vs. 12 pmol La in the mustard) indicating that the radish is the most preferable sprout for the phytoremediation of lanthanides. PMID:22555541

Anan, Yasumi; Awaya, Yumi; Ogihara, Yurie; Yoshida, Miyuki; Yawata, Ayako; Ogra, Yasumitsu

2012-07-01

279

Lanthanide-based functional misfit-layered nanotubes.  

PubMed

The synthesis of nanotubes from layered compounds has generated substantial scientific interest. "Misfit" layered compounds (MLCs) of the general formula [(MX)(1+x)](m)[TX2]n, where M can include Pb, Sb, rare earths; T=Cr, Nb, and X=S, Se can form layered structures, even though each sub-system alone is not necessarily a layered or a stable compound. A simple chemical method is used to synthesize these complex nanotubes from lanthanide-based misfit compounds. Quaternary nanotubular structures formed by partial substitution of the lanthanide atom in nanotubes by other elements are also confirmed. The driving force and mechanism of formation of these nanotubes is investigated by systematic temperature and time-dependent studies. A stress-inducement mechanism is proposed to explain the formation of the nanotubes. The resulting materials may find applications in fields that include thermoelectrics, light emitters, and catalysis and address fundamental physical issues in low dimensions. PMID:24898937

Panchakarla, Leela S; Popovitz-Biro, Ronit; Houben, Lothar; Dunin-Borkowski, Rafal E; Tenne, Reshef

2014-07-01

280

Novel microporous lanthanide silicates with tobermorite-like structure.  

PubMed

The synthesis and structural characterization of microporous lanthanide silicates (Na(1.08)K(0.5)Ln(1.14)Si(3)O(8.5).1.78H(2)O, Ln = Eu, Tb, Sm, Ce) are reported. The structure of these solids is closely related with the structure of hydrated calcium silicate minerals known as tobermorites and was solved by powder X-ray diffraction ab initio (direct) methods and further characterized by chemical analysis, thermogravimetry, scanning electron microscopy, (23)Na and (29)Si MAS NMR and luminescence spectroscopy. These materials combine microporosity with interesting photoluminescence properties, and their structural flexibility allows fine-tuning of luminescence properties, by introducing a second type of lanthanide ion in the framework. Thus, they may find applications in new types of sensors. PMID:14624607

Ferreira, Artur; Ananias, Duarte; Carlos, Luís D; Morais, Cláudia M; Rocha, João

2003-11-26

281

Curcuminoid ligands for sensitization of near-infrared lanthanide emission.  

PubMed

Fluorescent lanthanide complexes were synthesized using a non-phenolic analog of curcumin as the principal chromophoric chelating ligand. Sensitized, near-infrared fluorescence is observed in these complexes as a result of photo-excitation of the chromophoric ligands, population of the molecular triplet state, and transfer of energy to the emitting lanthanide ion. For the purpose of intra-molecular energy transfer, the triplet states of curcuminoid ligands are more favorably matched with the excited electronic states of neodymium and ytterbium ions than those associated with less conjugated beta-diketonate ligands. Sensitization of fluorescence through an internal redox reaction, thought to occur in other ytterbium complexes, is predicted to be less probable under the present circumstances. PMID:16167217

Seltzer, M D; Fallis, S; Hollins, R A; Prokopuk, N; Bui, R N

2005-07-01

282

Oxygen defects of actinide, lanthanide oxides, and their solid solutions  

NASA Astrophysics Data System (ADS)

To reveal the nature of the oxygen defects in actinide, lanthanide oxides, and their solid solutions, the relations between the molar ratio of oxygen to metal, O/M, and the oxygen potentials of these oxides in our previous studies were reviewed. These relations were then compared with those between O/M and the oxygen potentials in the literature, with reference to the phase relations and the constituent cationic valences and radii of these oxides. Consequently, we found consistent properties in the relations between O/M and the oxygen potentials of actinide, lanthanide oxides, and their solid solutions, in addition to the dependence of the relations on the crystal structures (e.g., fluorite-type, pyrochlore-type, and cubic sesquioxide-type).

Otobe, Haruyoshi

2013-11-01

283

A TRUEX-based separation of americium from the lanthanides  

SciTech Connect

Abstract: The inextractability of the actinide AnO2+ ions in the TRUEX process suggests the possibility of a separation of americium from the lanthanides using oxidation to Am(V). The only current method for the direct oxidation of americium to Am(V) in strongly acidic media is with sodium bismuthate. We prepared Am(V) over a wide range of nitric acid concentrations and investigated its solvent extraction behavior for comparison to europium. While a separation is achievable in principal, the presence of macro amounts of cerium competes for the sparingly soluble oxidant and the oxidant itself competes for CMPO complexation. These factors conspire to reduce the Eu/Am separation factor from ~40 using tracer solutions to ~5 for extractions from first cycle raffinate simulant solution. To separate pentavalent americium directly from the lanthanides using the TRUEX process, an alternative oxidizing agent will be necessary.

Bruce J. Mincher; Nicholas C. Schmitt; Mary E. Case

2011-03-01

284

Luminescent lanthanide cryptates: from the bench to the bedside.  

PubMed

The design and application of luminescent lanthanide cryptates for sensing biological interactions is highlighted through the review of the work performed in our laboratory and with academic collaborations. The path from the initial applications probing biochemical interaction in vitro to "state-of-the-art" cellular assays toward clinical applications using homogeneous time-resolved fluorescence technology is described. An overview of the luminescent lanthanide macrocyclic compounds developed at Cisbio in the recent past is given with an emphasis on specific constraints required by specific applications. Recent assays for drug-discovery and diagnostic purposes using both antibody-based and suicide-enzyme-based technology are illustrated. New perspectives in the field of molecular medicine and time-resolved microscopy are discussed. PMID:24392868

Zwier, Jurriaan M; Bazin, Hervé; Lamarque, Laurent; Mathis, Gérard

2014-02-17

285

In vivo three-dimensional molecular imaging with Biosensor Imaging of Redundant Deviation in Shifts (BIRDS) at high spatiotemporal resolution.  

PubMed

Spectroscopic signals which emanate from complexes between paramagnetic lanthanide (III) ions (e.g. Tm(3+)) and macrocyclic chelates (e.g. 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate, or DOTMA(4-)) are sensitive to physiology (e.g. temperature). Because nonexchanging protons from these lanthanide-based macrocyclic agents have relaxation times on the order of a few milliseconds, rapid data acquisition is possible with chemical shift imaging (CSI). Thus, Biosensor Imaging of Redundant Deviation in Shifts (BIRDS) which originate from nonexchanging protons of these paramagnetic agents, but exclude water proton detection, can allow molecular imaging. Previous two-dimensional CSI experiments with such lanthanide-based macrocyclics allowed acquisition from ~12-?L voxels in rat brain within 5 min using rectangular encoding of k space. Because cubical encoding of k space in three dimensions for whole-brain coverage increases the CSI acquisition time to several tens of minutes or more, a faster CSI technique is required for BIRDS to be of practical use. Here, we demonstrate a CSI acquisition method to improve three-dimensional molecular imaging capabilities with lanthanide-based macrocyclics. Using TmDOTMA(-), we show datasets from a 20 × 20 × 20-mm(3) field of view with voxels of ~1 ?L effective volume acquired within 5 min (at 11.7 T) for temperature mapping. By employing reduced spherical encoding with Gaussian weighting (RESEGAW) instead of cubical encoding of k space, a significant increase in CSI signal is obtained. In vitro and in vivo three-dimensional CSI data with TmDOTMA(-), and presumably similar lanthanide-based macrocyclics, suggest that acquisition using RESEGAW can be used for high spatiotemporal resolution molecular mapping with BIRDS. PMID:23881869

Coman, Daniel; de Graaf, Robin A; Rothman, Douglas L; Hyder, Fahmeed

2013-11-01

286

Color tuning and white light emission via in situ doping of luminescent lanthanide metal-organic frameworks.  

PubMed

Isostructural lanthanide metal-organic frameworks (MOFs) are synthesized through the spontaneous self-assembly of H3BTPCA (1,1',1?-(benzene-1,3,5-triyl)tripiperidine-4-carboxylic acid) ligands and lanthanide ions (we term these MOFs Ln-BTPCA, Ln = La(3+), Tb(3+), Sm(3+), etc.). Prompted by the observation that the different lanthanide ions have identical coordination environment in these MOFs, we explored and succeeded in the preparation of mixed-lanthanide analogues of the single-lanthanide MOFs by way of in situ doping using a mixture of lanthanide salts. With careful adjustment of the relative concentration of the lanthanide ions, the color of the luminescence can be modulated, and white light-emission can indeed be achieved. The mechanisms possibly responsible for the observed photophysical properties of these mixed-lanthanide MOFs are also discussed. PMID:24328271

Tang, Qun; Liu, Shuxia; Liu, Yiwei; He, Danfeng; Miao, Jun; Wang, Xingquan; Ji, Yujuan; Zheng, Zhiping

2014-01-01

287

Structure of X-ray photoelectron spectra of lanthanide compounds  

Microsoft Academic Search

The results of the X-ray photoelectron spectroscopy studies of the electronic structures of trifluorides, oxides and other compounds of Sc, Y and lanthanides (Ln) from La to Lu, except for Pm, in the binding energy range from 0 to 1350 eV are generalised. The established dependences of the Ln4f binding energies and the relative intensities of lines on the atomic

Yurii A. Teterin; Anton Yu Teterin

2002-01-01

288

Complexes of Alkyl Esters of Ethylidenediphosphonic Acids with Lanthanide Nitrates  

Microsoft Academic Search

The lanthanide complexes LnL2(NO3)33a?c and 5a?c, where Ln is La, Ce and Sm and L are tetraethyl esters of ethylidenediphosphonic acid 1 (for complexes 3) and tetraisopropyl esters of ethylidenediphosphonic acid 4 (for complexes 5) were synthesized and characterized by elemental analysis, IR and NMR spectroscopy. The crystal structure of DyL2(NO3)37 (L is tetraisopropyl ester of methylenediphosphonic acid) was determined

Vladislav Arabadzhiev; Jordanka Petrova; Erhard T. K. Haupt; Jürgen Kopf; Isabelle Nevoigt

2008-01-01

289

Thermal Decomposition of Lanthanide, Yttrium, and Scandium Oxalates and Carbonates  

NASA Astrophysics Data System (ADS)

Data concerning the thermal decomposition of lanthanide, yttrium, and scandium oxalates and carbonates are surveyed. The complexity of the process, the large number of stages involved, and the dependence of the composition of the intermediates in the thermal transformations on the experimental conditions is noted. Certain process characteristics have been discovered and it is concluded that the decomposition process depends on the ionic radius of the metal. The bibliography includes 83 references.

Sharov, Vyacheslav A.; Bezdenezhnykh, G. V.

1981-07-01

290

A Revised Periodic Table: With the Lanthanides Repositioned  

Microsoft Academic Search

The lanthanide elements from lanthanum to lutetium inclusive are incorporated into the body of the periodic table. They are\\u000a subdivided into three sub-groups according to their important oxidation states: La to Sm, Eu to Tm, Yb and Lu, so that Eu\\u000a and Yb fall directly below Ba; La, Gd, Lu form a column directly below Y; Ce and Tb fall

Michael Laing

2005-01-01

291

Dissolution-enhanced luminescent bioassay based on inorganic lanthanide nanoparticles.  

PubMed

Conventional dissociation-enhanced lanthanide fluoroimmunoassays (DELFIA) using molecular probes suffer from a low labeling ratio of lanthanide ions (Ln(3+) ) per biomolecule. Herein, we develop a unique bioassay based on the dissolution-enhanced luminescence of inorganic lanthanide nanoparticles (NPs). As a result of the highly concentrated Ln(3+) ?ions in a single Ln(3+) ?NP, an extremely high Ln(3+) ?labeling ratio can be achieved, which amplifies significantly the luminescence signal and thus improves the detection sensitivity compared to DELFIA. Utilizing sub-10?nm NaEuF4 ?NPs as dissolution-enhanced luminescent nanoprobes, we demonstrate the successful in?vitro detection of carcinoembryonic antigen (CEA, an important tumor marker) in human serum samples with a record-low detection limit of 0.1?pg?mL(-1) (0.5?fM). This value is an improvement of approximately 3?orders of magnitude relative to that of DELFIA. The dissolution-enhanced luminescent bioassay shows great promise in versatile bioapplications, such as ultrasensitive and multiplexed in?vitro detection of disease markers in clinical diagnosis. PMID:25131425

Zhou, Shanyong; Zheng, Wei; Chen, Zhuo; Tu, Datao; Liu, Yongsheng; Ma, En; Li, Renfu; Zhu, Haomiao; Huang, Mingdong; Chen, Xueyuan

2014-11-10

292

Magnetic Relaxation Mechanisms in Lanthanide Single Molecule Magnets  

NASA Astrophysics Data System (ADS)

Ab initio investigation of multiplet spectrum of lanthanides in archetypal coordination geometries shows an unexpected regular structure consisting of (i) mirror symmetry of anisotropic magnetic properties of doublet states, (ii) high magnetic axiality of low-lying and high-lying doublets, comparable to complexes with ideal axial symmetry, and (iii) the strong rotation of the anisotropy axes of individual doublets [1]. The obtained high axiality of the ground doublet states explains the SMM behaviour of low-symmetry lanthanide complexes. Ab initio calculations predict that depending on the relative orientation of anisotropy axes in different doublet states, the relaxation can proceed via the first or the second excited state. Here we report new lanthanide cage complexes where two competing relaxation pathways through the first and second excited states are observed, leading to very high energy barriers for loss of magnetisation [2]. [1] L. Ungur, L.F. Chibotaru, P.C.C.P., 2011, 13, 20086--20090. [2] R.J. Blagg, L. Ungur, F. Tuna, D. Collison, E.J.L. McInnes L.F. Chibotaru, R.E.P. Winpenny,. Nat. Chem., submitted.

Chibotaru, Liviu; Ungur, Liviu; McInnes, Eric; Winpenny, Richard

2013-03-01

293

Characterization and Classification of Lanthanides by Multivariate-Analysis Methods  

NASA Astrophysics Data System (ADS)

A chemometric study was conducted on a data set consisting of 18 characteristics, mainly physical properties of the 14 lanthanides and lanthanum, including Sc and Y. Classical methods of multivariate analysis, namely, principal component analysis (PCA) and cluster analysis (CA) were applied. The results obtained by using the Statistica software package are presented and discussed concerning the correlations between the properties and those between the elements themselves. The discussion and findings are based on the tables of correlation, the eigenvectors and eigenvalues of PCA, the 2D- and 3D-representations of the loadings of variables and scores of the elements corresponding to the first principal components, including also the dendrograms obtained by using CA. Loadings scatterplots are used as a display tool for examining the relationships between properties, looking for trends, grouping, or outliers. In the same way, the scatterplots of scores emphasized the difference between La and the lanthanides on the one side and Sc and Y on the other and support setting Lu as their homologue, rather than La. On the basis of these findings, a ”periodic system“ of the lanthanides is suggested that agrees well with chemical intuition.

Horovitz, Ossi; Sârbu, Costel

2005-03-01

294

Photoacoustic Spectral Study of Lanthanide Complexes Doped in Silica Matrix  

NASA Astrophysics Data System (ADS)

Lanthanide phenanthroline (phen) complexes Eu(phen)2Cl3{\\cdot } 2H2O and Nd(phen)2Cl3{\\cdot } 2H2O were incorporated into a silica matrix by an ultrasonic assisted sol-gel method. In the region of ligand absorption, the photoacoustic (PA) intensity for a lanthanide complex is the same as in wet gels. Upon heat treatment at 120° C, however, the PA intensity of a Nd(phen)2Cl3{\\cdot }2H2 O-doped sample is much larger than that of a Eu(phen)2Cl3 {\\cdot } 2H2 O-doped sample. The characteristic emissions of Eu^{3+} complex-doped samples were used to interpret the stability of the complex in silica matrices. The luminescence spectra are consistent with the PA results. The study indicates that phen can only coordinate with lanthanide ions in a silica matrix after a suitable heat treatment. Moreover, the covalency parameters and PA bands of f-f transionts of Nd^{3+} have been used to study the formation of the complex in a silica matrix.

Yang, Y. T.; Gao, B.; Zhang, S. Y.; Liu, X. J.

2014-05-01

295

Magnetic circular dichroism of porphyrin lanthanide m(3+) complexes.  

PubMed

Lanthanide complexes exhibit interesting spectroscopic properties yielding many applications as imaging probes, natural chirality amplifiers, and therapeutic agents. However, many properties are not fully understood yet. Therefore, we applied magnetic circular dichroism (MCD) spectroscopy, which provides enhanced information about the underlying electronic structure to a series of lanthanide compounds. The metals in the M(3+) state included Y, La, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Lu; the spectra were collected for selected tetraphenylporphin (TPP) and octaethylporphin (OEP) complexes in chloroform. While the MCD and UV-VIS absorption spectra were dominated by the porphyrin signal, metal binding significantly modulated them. MCD spectroscopy was found to be better suited to discriminate between various species than absorption spectroscopy alone. The main features and trends in the lanthanide series observed in MCD and absorption spectra of the complexes could be interpreted at the Density Functional Theory (DFT) level, with effective core potentials on metal nuclei. The sum over state (SOS) method was used for simulation of the MCD intensities. The combination of the spectroscopy and quantum-chemical computations is important for understanding the interactions of the metals with the organic compounds. Chirality 26:655-662, 2014. © 2014 Wiley Periodicals, Inc. PMID:25116761

Andrushchenko, Valery; Padula, Daniele; Zhivotova, Elena; Yamamoto, Shigeki; Bou?, Petr

2014-10-01

296

Semiempirical Quantum Chemistry Model for the Lanthanides: RM1 (Recife Model 1) Parameters for Dysprosium, Holmium and Erbium  

PubMed Central

Complexes of dysprosium, holmium, and erbium find many applications as single-molecule magnets, as contrast agents for magnetic resonance imaging, as anti-cancer agents, in optical telecommunications, etc. Therefore, the development of tools that can be proven helpful to complex design is presently an active area of research. In this article, we advance a major improvement to the semiempirical description of lanthanide complexes: the Recife Model 1, RM1, model for the lanthanides, parameterized for the trications of Dy, Ho, and Er. By representing such lanthanide in the RM1 calculation as a three-electron atom with a set of 5 d, 6 s, and 6 p semiempirical orbitals, the accuracy of the previous sparkle models, mainly concentrated on lanthanide-oxygen and lanthanide-nitrogen distances, is extended to other types of bonds in the trication complexes’ coordination polyhedra, such as lanthanide-carbon, lanthanide-chlorine, etc. This is even more important as, for example, lanthanide-carbon atom distances in the coordination polyhedra of the complexes comprise about 30% of all distances for all complexes of Dy, Ho, and Er considered. Our results indicate that the average unsigned mean error for the lanthanide-carbon distances dropped from an average of 0.30 Å, for the sparkle models, to 0.04 Å for the RM1 model for the lanthanides; for a total of 509 such distances for the set of all Dy, Ho, and Er complexes considered. A similar behavior took place for the other distances as well, such as lanthanide-chlorine, lanthanide-bromine, lanthanide, phosphorus and lanthanide-sulfur. Thus, the RM1 model for the lanthanides, being advanced in this article, broadens the range of application of semiempirical models to lanthanide complexes by including comprehensively many other types of bonds not adequately described by the previous models. PMID:24497945

Filho, Manoel A. M.; Dutra, Jose Diogo L.; Rocha, Gerd B.; Simas, Alfredo M.; Freire, Ricardo O.

2014-01-01

297

Preparation and luminescence properties of lanthanide (Eu3+, Sm3+) complexes and their hectorite-based composites.  

PubMed

The complexes of europium and samarium with phthalates ligands were synthesized and characterized. The luminescence behaviors of the lanthanide complexes as well as their hectorite-based composites were investigated by fluorescence spectra. The results indicated that the lanthanide complexes showed slightly lower intensities in hectorite matrix than that of corresponding pure complexes. The lanthanide ion relative fluorescence intensity (LRFI) was enhanced when the lanthanide complexes were doped into hectorite. PMID:20036189

Ma, Jun; Jia, Yongzhong; Jing, Yan; Sun, Jinhe; Yao, Ying; Wang, Xiaohua

2010-02-01

298

Selective removal of lanthanides from natural waters, acidic streams and dialysate  

PubMed Central

The increased demand for the lanthanides in commercial products result in increased production of lanthanide containing ores, which increases public exposure to the lanthanides, both from various commercial products and from production wastes/effluents. This work investigates lanthanide (La, Ce, Pr, Nd, Eu, Gd and Lu) binding properties of self-assembled monolayers on mesoporous silica supports (SAMMS™), that were functionalized with diphosphonic acid (DiPhos), acetamide phosphonic acid (AcPhos), propionamide phosphonic acid (Prop-Phos), and 1-hydroxy-2-pyridinone (1,2-HOPO), from natural waters (river, ground and sea waters), acid solutions (to mimic certain industrial process streams), and dialysate. The affinity, capacity, and kinetics of the lanthanide sorption, as well as regenerability of SAMMS materials were investigated. Going from the acid side over to the alkaline side, the AcPhos- and DiPhos-SAMMS maintain their outstanding affinity for lanthanides, which enable the use of the materials in the systems where the pH may fluctuate. In acid solutions, Prop-Phos- and 1,2-HOPO-SAMMS have differing affinity along the lanthanide series, suggesting their use in chromatographic lanthanide separation. Over 95% of 100 µg/L of Gd in dialysate was removed by the Prop-Phos-SAMMS after 1 min and 99% over 10 min. SAMMS can be regenerated with an acid wash (0.5 M HCl) without losing the binding properties. Thus, they have a great potential to be used as in large-scale treatment of lanthanides, lanthanide separation prior to analytical instruments, and in sorbent dialyzers for treatment of acute lanthanide poisoning. PMID:19345006

Yantasee, Wassana; Fryxell, Glen E.; Addleman, R. Shane; Wiacek, Robert J.; Koonsiripaiboon, View; Pattamakomsan, Kanda; Sukwarotwat, Vichaya; Xu, Jide; Raymond, Kenneth N.

2009-01-01

299

Selective Removal of Lanthanides from Natural Waters, Acidic Streams and Dialysate  

SciTech Connect

The increased demand for the lanthanides in commercial products result in increased production of lanthanide containing ores, increasing public exposure to the lanthanides, both from various commercial products and from production wastes/effluents. This work investigates lanthanide (La, Ce, Pr, Nd, Eu, Gd, Lu) binding properties of self-assembled monolayers on mesoporous silica supports (SAMMS®) that were functionalized with diphosphonic acid (DiPhos), acetamide phosphonic acid (AcPhos), propionamide phosphonic acid (ProPhos), and 1-hydroxy-2-pyridinone (1,2-HOPO) from natural waters (river, ground, and sea waters), acid solutions (to mimic certain industrial process streams), and dialysate and compares their performance to a high surface area activated carbon. The properties include sorption affinity, capacity, and sorption kinetics. Stability and regenerability of SAMMS materials were also investigated. Going from the acid side over to the alkaline side, the AcPhos- and DiPhos-SAMMS maintain their outstanding affinity for lanthanides, which enable the use of the materials in the systems where the pH may fluctuate. While the activated carbon is as effective as 1,2-HOPO-SAMMS for capturing lanthanides in natural (alkaline) waters, it has no affinity in acid solutions (pH 2.4) and low affinity in carbonate-rich dialysate. Over 99% of 100 ug/L of Gd in dialysate was removed by the ProPhos-SAMMS after ten minutes. SAMMS can be regenerated with an acid wash (0.5 M HCl) without losing the binding properties, for a number of regeneration cycles. In acid solutions, PhoPhos- and 1,2-HOPO-SAMMS have differing affinity along the lanthanide series, suggesting their potential for chromatographic lanthanide separations. Thus, SAMMS materials have a great potential to be used as sorbents in large scale treatment of lanthanides, lanthanide separation prior to analytical instruments, and sorbent dialyzers for lanthanide clearances.

Yantasee, Wassana; Fryxell, Glen E.; Addleman, Raymond S.; Wiacek, Robert J.; Koonsiripaiboon, View; Pattamakomsan, Kanda; Sukwarotwat, Vichaya; Xu, Jide; Raymond, Kenneth N.

2009-09-15

300

Chemical shifts in biomolecules  

PubMed Central

Summary NMR chemical shifts are sensitive probes of stucture and dynamics in proteins. Empirical models, based on a large database of measured shifts, take an input structure and provide increasingly accurate estimates of the corresponding shifts. Quantum chemical calculations can provide the same information, with greater generality but (currently) with less accuracy. These methods are now providing new ways to approach NMR structure determination, and new insights into the conformational dynamics of proteins. PMID:23422068

Case, David A.

2013-01-01

301

A simple procedure for crystallization of the Schiff reagent.  

PubMed

Formation of crystals in Schiff reagents prepared from SO2 gas previously has been reported either soon after preparation, using high dye concentrations and heating, or after long periods of storage at room temperature. With the first type of procedure only a low yield of crystals accompanied by dye precipitation was obtained. Crystallization without dye precipitation took place if the reagent, prepared with pararosaniline base or chloride in a saturated SO2 solution, was stored for a sufficient time at room temperature in partly filled flasks. These crystals remained colorless if washed with acid alcohol after being separated by filtration. Schiff reagents layered with paraffin oil or supplemented with 0.1 M hydroquinone took much longer to crystallize, suggesting that crystallization is promoted by the partial oxidation of sulfurous acid to sulfuric acid. A high yield of crystals can be obtained at room temperature after as little as 24 hr by adding 0.04 M of H2SO4 to a Schiff reagent prepared with 2% pararosaniline chloride in a saturated SO2 solution. A Schiff reagent prepared with only 0.2% of these crystals gives an intense staining in the Feulgen and in the Periodic acid-Schiff reactions. PMID:8393350

Galassi, L

1993-05-01

302

Lanthanide bis(trifluoromethylsulfonyl)amides vs. trifluoromethylsulfonates as catalysts for Friedel–Crafts acylations  

Microsoft Academic Search

The use of catalytic amounts: 1mol% or less of perfluoroalkyl lanthanide salts as homogeneous catalysts for Friedel–Crafts acylations in non-hazardous solvents is thereafter investigated. Lanthanide bis(trifluoromethylsulfonyl)amides are better catalysts than the triflate analogues towards the acetylation of activated aromatic rings.

Fanny Duris; Denise Barbier-Baudry; Alain Dormond; Jean Roger Desmurs; Jean Marie Bernard

2002-01-01

303

Lanthanide Selective Sorbents: Self-Assembled Monolayers on Mesoporous Supports (SAMMS)  

Microsoft Academic Search

Through the marriage of mesoporous ceramics with self-assembled monolayer chemistry, the genesis of a powerful new class of environmental sorbent materials has been realized. By coating the mesoporous ceramic backbone with a monolayer terminated with a lanthanide-specific ligand, it is possible to couple high lanthanide binding affinity with the high loading capacity (resulting from the extremely high surface area of

Glen E. Fryxell; Hong Wu; Yuehe Lin; Wendy J. Shaw; Jerome C. Birnbaum; John C. Linehan; Zimin Nie; Kenneth M. Kemner; Shelley Kelly

2004-01-01

304

Process for recovering yttrium and lanthanides from wet-process phosphoric acid  

SciTech Connect

Process for recovering yttrium and lanthanides from wet-process phosphoric acid by adding a flocculant to the phosphoric acid, separating out the resultant precipitate and then recovering yttrium and lanthanides from the precipitate. Uranium is recovered from the remaining phosphoric acid.

Janssen, J.A.; Weterings, C.A.

1983-06-28

305

Review: Solvent Systems Combining Neutral and Acidic Extractants for Separating Trivalent Lanthanides from the Transuranic Elements  

Microsoft Academic Search

This paper is a review of recent publications that have focused on combined extractant systems for separating trivalent actinides from the lanthanides. These mixed solvent systems combine an acidic extractant with a neutral extractant to achieve the actinide\\/lanthanide separation. Depending on the neutral extractant used, three categorizations of systems can be considered, including combinations of acidic extractants with 1) diamides,

Gregg J. Lumetta; Artem V. Gelis; George F. Vandegrift

2010-01-01

306

Applications of the Judd-Ofelt theory in lanthanide-chelidamic acid complexation  

NASA Astrophysics Data System (ADS)

The coordination chemistry of trivalent lanthanides with chelidamic acid was studied using fluorescence and absorption spectroscopic methods. The speciation was determined using Eu(III) fluorescence techniques. The stability constants and the oscillator strengths were determined for the Ho(III) complexes from absorbance measurements of a Ho(III) hypersensitive transition. The lanthanide coordination chemistry of chelidamic acid and dipicolinic acid is compared.

Choppin, Gergory R.; Fugate, Glenn A.

307

Applications of the Judd—Ofelt theory in lanthanide—chelidamic acid complexation  

Microsoft Academic Search

The coordination chemistry of trivalent lanthanides with chelidamic acid was studied using fluorescence and absorption spectroscopic methods. The speciation was determined using Eu(III) fluorescence techniques. The stability constants and the oscillator strengths were determined for the Ho(III) complexes from absorbance measurements of a Ho(III) hypersensitive transition. The lanthanide coordination chemistry of chelidamic acid and dipicolinic acid is compared.

GERGORY R. CHOPPIN; GLENN A. FUGATE

2003-01-01

308

Applications of the Judd-Ofelt theory in lanthanide-chelidamic acid complexation  

Microsoft Academic Search

The coordination chemistry of trivalent lanthanides with chelidamic acid was studied using fluorescence and absorption spectroscopic methods. The speciation was determined using Eu(III) fluorescence techniques. The stability constants and the oscillator strengths were determined for the Ho(III) complexes from absorbance measurements of a Ho(III) hypersensitive transition. The lanthanide coordination chemistry of chelidamic acid and dipicolinic acid is compared.

Gergory R. Choppin; Glenn A. Fugate

2003-01-01

309

Style Shift in Translation  

ERIC Educational Resources Information Center

The phenomenon of style shift in translated texts is ascribed mainly to textual incompatibility in terms of rhetorical asymmetry and divergence at the formality level. Mandatory shifts result from a systematic dissimilarity between the source language and the target language in terms of the underlying system of syntax, semantics and rhetorical…

Al-Qinai, Jamal

2009-01-01

310

Preparation and Purification of Zinc Sulphinate Reagents for Organic Synthesis  

PubMed Central

SUMMARY The present protocol details the synthesis of zinc bis(alkanesulphinate)s that can be used as general reagents for the formation of radical species. The zinc sulphinates described herein have been generated from the corresponding sulphonyl chlorides by treatment with zinc dust. The products may be used crude, or a simple purification procedure may be performed to minimize incorporation of water and zinc chloride. Elemental analysis has been conducted in order to confirm the purity of the zinc sulphinate reagents; reactions with caffeine have also been carried out to verify the reactivity of each batch that has been synthesized. Although the synthesis of the zinc sulphinate salts generally proceeds within 3 h, workup can take up to 24 h and purification can take up to 3 h. Following the steps in this protocol would enable the user to generate a small toolkit of zinc sulphinate reagents over the course of one week. PMID:23640168

O'Hara, Fionn; Baxter, Ryan D.; O'Brien, Alexander G.; Collins, Michael R.; Dixon, Janice A.; Fujiwara, Yuta; Ishihara, Yoshihiro; Baran, Phil S.

2014-01-01

311

A peptidomimetic siRNA transfection reagent forhighly effectivegene silencing  

SciTech Connect

RNA interference (RNAi) techniques hold forth great promisefor therapeutic silencing of deleterious genes. However, clinicalapplications of RNAi require the development of safe and efficientmethods for intracellular delivery of small interfering RNA (siRNA)oligonucleotides specific to targeted genes. We describe the use of alipitoid, a cationic oligopeptoid phospholipid conjugate, for non-viraltransfection of synthetic siRNA oligos in cell culture. Thispeptidomimetic delivery vehicle allows for efficient siRNA transfectionin a variety of human cell lines with negligible toxicity and promotesextensive downregulation of the targeted genes at both the protein andthe mRNA level. We compare the lipitoid reagent to a standard commercialtransfection reagent. The lipitoid is highly efficient even in primaryIMR-90 human lung fibroblasts in which other commercial reagents aretypically ineffective.

Utku, Yeliz; Dehan, Elinor; Ouerfelli, Ouathek; Piano, Fabio; Zuckermann, Ronald N.; Pagano, Michele; Kirshenbaum, Kent

2006-05-17

312

Allylic functionalization of unactivated olefins with Grignard reagents.  

PubMed

New advances in the functionalization of unactivated olefins with carbon nucleophiles have provided more efficient and practical approaches to convert inexpensive starting materials into valuable products. Recent examples have been reported with stabilized carbon nucleophiles, tethered carbon nucleophiles, diazoesters, and trifluoromethane donors. A general method for functionalizing olefins with aromatic, aliphatic, and vinyl Grignard reagents was developed. In a one-pot process, olefins are oxidized by a commercially available reagent to allylic electrophiles, which undergo selective copper-catalyzed allylic alkylation with Grignard reagents. Products are formed in high yield and with high regioselectivity. This was utilized to synthesize a series of skipped dienes, a class of compounds that are prevalent in natural products and are difficult to synthesize by known allylic alkylation methods. PMID:24458538

Bao, Hongli; Bayeh, Liela; Tambar, Uttam K

2014-02-01

313

Reagents for the preparation of two oligonucleotides per synthesis (TOPS).  

PubMed Central

In order to increase the efficiency of use of automated DNA synthesizers (i.e. the number of oligomers prepared per day), we have devised and prepared novel phosphoramidite reagents that contain a linking group which, while stable under the normal synthesis conditions, is cleaved under basic conditions. When one of these linkers is introduced at the desired position in the synthesis of an oligonucleotide, subsequent detritylation enables the synthesis of a second oligonucleotides sequence upon the first. During deprotection of the oligonucleotide with ammonium hydroxide, the chain is cleaved at either side of the points of introduction of the novel reagent, generating two oligonucleotides free in solution. These reagents are of particular use in applications where oligomers are used in pairs (such as PCR, chemical synthesis of genes etc.) and means that an automated synthesis facility can be used more efficiently, without the need for operator intervention, after the working day is over. Images PMID:8065912

Hardy, P M; Holland, D; Scott, S; Garman, A J; Newton, C R; McLean, M J

1994-01-01

314

Evaluation of novel derivatisation reagents for the analysis of oxysterols  

PubMed Central

Oxysterols are oxidised forms of cholesterol that are intermediates in the synthesis of bile acids and steroid hormones. They are also ligands to nuclear and G protein-coupled receptors. Analysis of oxysterols in biological systems is challenging due to their low abundance coupled with their lack of a strong chromophore and poor ionisation characteristics in mass spectrometry (MS). We have previously used enzyme-assisted derivatisation for sterol analysis (EADSA) to identify and quantitate oxysterols in biological samples. This technique relies on tagging sterols with the Girard P reagent to introduce a charged quaternary ammonium group. Here, we have compared several modified Girard-like reagents and show that the permanent charge is vital for efficient MSn fragmentation. However, we find that the reagent can be extended to include sites for potential stable isotope labels without a loss of performance. PMID:24525124

Crick, Peter J.; Aponte, Jennifer; Bentley, T. William; Matthews, Ian; Wang, Yuqin; Griffiths, William J.

2014-01-01

315

Synthesis and structural properties of lanthanide complexes formed with tropolonate ligands.  

PubMed

We have previously reported the unique luminescence properties of ML4 complexes formed between tropolonate ligands and a series of lanthanide cations, several of them emitting in the near-infrared domain. The synthesis and composition of ML4 lanthanide tropolonate complexes have been previously described in the literature, but no structural information has been available so far. In this work, the crystal structures of several lanthanide tropolonate complexes (Ln3+ = Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+, Lu3+) have been isolated and systematically analyzed by X-ray diffraction and compared by using different criteria including the Kepert formalism. Such comparative work is rare in lanthanide coordination chemistry. The analysis of the structures in the solid state reveals that although the packing of the ML4 complexes depends on the nature of the metal ion, the coordination geometries around the different lanthanides is virtually similar for all the cations that have been analyzed; an indication that lanthanide-centered f orbitals play a role in controlling this coordination geometry. Analysis of the solution's behavior by stability constant determination reveals the formation of complexes with similar ML4 stoichiometries as those observed in the solid state. Nevertheless, analysis of the luminescence lifetimes indicates that the coordination environment around the lanthanide cations are different in the solid state and in solution, with the presence of one molecule of water bound to the lanthanide cation in solution. The presence of such a water molecule is a significant source of nonradiative deactivation of the excited states of the lanthanide cations, an unfavorable condition that leads to significant loss in fluorescence intensity of these lanthanide complexes. This exemplifies that such comparative analysis between the solid state and solution is important for the rationalization of the luminescence properties of the complexes. This analysis will aid us in optimizing ligand design for improved photophysical properties of the complex. PMID:17622139

Zhang, Jian; Badger, Paul D; Geib, Steven J; Petoud, Stéphane

2007-08-01

316

NMR chemical shift in an electronic state with arbitrary degeneracy.  

PubMed

We present a theory of nuclear magnetic resonance shielding tensors for electronic states with arbitrary degeneracy. The shieldings are here expressed in terms of generalized Zeeman (g((k))) and hyperfine (A((k))) tensors, of all ranks k allowed by the size of degeneracy. Contrary to recent proposals [T.?O. Pennanen and J. Vaara, Phys. Rev. Lett. 100, 133002 (2008)], our theory is valid in the strong spin-orbit coupling limit. Ab initio calculations for the fourfold degenerate ?(8) ground state of lanthanide-doped fluorite crystals CaF(2):Ln (Ln=Pr(2+), Nd(3+), Sm(3+), and Dy(3+)) show that previously neglected contributions can account for more than 50% of the paramagnetic shift. PMID:23006364

Van den Heuvel, Willem; Soncini, Alessandro

2012-08-17

317

NMR Chemical Shift in an Electronic State with Arbitrary Degeneracy  

NASA Astrophysics Data System (ADS)

We present a theory of nuclear magnetic resonance shielding tensors for electronic states with arbitrary degeneracy. The shieldings are here expressed in terms of generalized Zeeman (g(k)) and hyperfine (A(k)) tensors, of all ranks k allowed by the size of degeneracy. Contrary to recent proposals [T. O. Pennanen and J. Vaara, Phys. Rev. Lett. 100, 133002 (2008)], our theory is valid in the strong spin-orbit coupling limit. Ab initio calculations for the fourfold degenerate ?8 ground state of lanthanide-doped fluorite crystals CaF2:Ln (Ln=Pr2+, Nd3+, Sm3+, and Dy3+) show that previously neglected contributions can account for more than 50% of the paramagnetic shift.

Van den Heuvel, Willem; Soncini, Alessandro

2012-08-01

318

A red-shifted fluorescent substrate for aldehyde dehydrogenase  

PubMed Central

Selection of cells positive for aldehyde dehydrogenase (ALDH) activity from a green fluorescent background is difficult with existing reagents. Here we report a red-shifted fluorescent substrate for ALDH, AldeRed 588-A, for labeling viable ALDHpos cells. We demonstrate that AldeRed 588-A successfully isolates ALDHhi human hematopoietic stem cells from heterogeneous cord blood mononuclear cells. AldeRed 588-A can be used for multi-color applications to fractionate ALDHpos cells in the presence of green fluorophores including the ALDEFLUOR™ reagent and cells expressing eGFP. AldeRed 588-A stains ALDHpos murine pancreatic centroacinar and terminal duct cells, as visualized by fluorescent microscopy. AldeRed588-A provides a useful tool to select stem cells or study ALDH within a green fluorescent background. PMID:24759454

Minn, Il; Wang, Haofan; Mease, Ronnie C.; Byun, Youngjoo; Yang, Xing; Wang, Julia; Leach, Steven D.; Pomper, Martin G.

2014-01-01

319

An ENSO shift revisited  

NASA Astrophysics Data System (ADS)

An influential 1996 paper presented a statistical analysis showing that the prolonged ENSO warm event of the early 1990's was inconsistent with the historical pattern of ENSO variability and therefore concluded that there had been a shift in ENSO behavior possibly connected to global warming. A fundamental problem with this earlier analysis is that the data used to test for a shift in ENSO behavior were not independent of the data used to identify the hypothetical shift. A new analysis is presented that avoids this problem by using more recent data. The results raise a question about the earlier finding.

Solow, Andrew R.

2006-11-01

320

Our World: Fluid Shift  

NASA Video Gallery

Learn about the circulatory system and how gravity aids blood flow in our bodies here on Earth. Find out how NASA flight surgeons help the astronauts deal with the fluid shift that happens during s...

321

Centrifugal atomization of lanthanide materials for cryogenic coolers  

SciTech Connect

Until recently, Pb was the preferred heat exchanger matrix material used in low temperature cryocoolers; however, the heat capacity of Pb drops drastically below {approximately}15K and new matrix materials based on the lanthanide elements have been developed. These materials magnetically order at low temperatures and the entropy change associated with ordering contributes to the materials` heat capacities. The drawback to widespread use of lanthanide intermetallic compounds in cryocoolers has been the difficulty in manufacturing high-quality particulates. The purpose of this project was to develop a technique for producing high-quality powders of lanthanide metals and lanthanide intermetallic compounds for use in cryocooler heat exchangers. A series of atomization experiments was performed using Er{sub 3}Ni, Nd, Nd{sub 3}Ni, and (Er{sub 0.5}Nd{sub 0.5}){sub 3}Ni. Atomization of these materials resulted in particles ranging from mostly spherical to extremely flattened. Analyses of size distributions for the experiments indicate that increased atomization disk speed and superheat result in smaller mean particle diameters and narrower size distributions. Chemical analyses of the atomized powders indicate that the CA/RQB technique produces particulate with much lower interstitial contamination than other techniques. The Er{sub 3}Ni and Nd{sub 3}Ni powders were predominantly of the desired phase and the (Er{sub 0.5}Nd{sub 0.5}){sub 3}Ni powder had one major and possibly three minor phases. The solidification morphology is typically fine dendritic or cellular with finer microstructure spacings near the particle surfaces. The Er{sub 3}Ni powders have higher heat capacities than gas atomized powders reported in literature. The heat capacity of Nd{sub 3}Ni has a peak which does not degrade dramatically with processing. The (Er{sub 0.5}Nd{sub 0.5}){sub 3}Ni material has a higher heat capacity compared to Er{sub 3}Ni, Nd{sub 3}Ni, and Nd at temperatures above 10K.

Osborne, M.G.

1994-01-04

322

New homochiral lanthanide(III) triflates in Lewis acid catalysis  

Microsoft Academic Search

New complexes of lanthanide(III) triflates with polyethylene glycol (HO(CH2CH2O)nH; n=2, 3, 4) and polyethyleneglycol dimethylether (CH3O(CH2CH2O)nCH3; n=2, 3, 4) ligands have been prepared and characterised by X-ray diffraction. These complexes are effective Lewis acid catalysts for the allylation of aldehydes with allyltributyltin, and for the Diels–Alder reaction. Complexes with new homochiral podand ligands have been synthesised and in one case

Helen C Aspinall; Nicholas Greeves; Edward G McIver

1998-01-01

323

Lithium Reagents DOI: 10.1002/anie.200603038  

E-print Network

Lithium Reagents DOI: 10.1002/anie.200603038 Lithium Diisopropylamide: Solution Kinetics Keywords: kinetics · lithium diisopropylamide · metalation · solvent effects · synthesis design D. B: lithium diiso- propylamide (LDA). LDA has played a profound role in organic synthesis, serving as the base

Collum, David B.

324

[Mechanism and kinetic of methyldopa removal by Fenton's reagent].  

PubMed

Methyldopa was selected to be degraded by Fenton's reagent in the experiment. The experimental results showed that it was feasible to the removal of Methyldopa and COD by Fenton's reagent. The mechanism of Methyldopa removal by Fenton's reagent was significantly different according to the Fe2+ :H2O2 ratio. With high ratio of Fe2+ :H2O2 (> or = 2), the Fenton reaction was coagulation enhanced by H2O2. With medium ratio of Fe2+ :H2O2 (= 1), the Fenton reaction could be characterized into two specific systems : oxidation and coagulation. With low ratio of Fe2+ :H2O2 (< or = 0.2), the Fenton reaction was oxidation, including H2O2 oxidation catalyzed by Fe2+ and degradation by a hydrated ferryl-complex Fe(aq)4+. With the analysis of the mechanism according to low ratio of Fe2+ :H2O2 (< or = 0.2), a kinetics model was adopted to describe the reaction, and the rate equation could provide the evidence for the main reaction pathway, which was fitted very well with the experiment data for the relative error below 10%. It was showed that the kinetic models could primary describe the process of the removal of Methyldopa and COD by Fenton's reagent. PMID:18624192

Tang, You-Min; Guan, Bao-Hong; Wu, Zhong-Biao

2008-05-01

325

Polymer-supported reagents: Application to separation science  

Microsoft Academic Search

Much of the waste at Hanford nuclear site exists in complex mixtures which must be separated prior to transfer to a safe storage area. The purpose of this review is to highlight new ligands that have been immobilized on polymers to form polymer-supported reagents which are selective for the complexation of targeted metal ions from multicomponent solutions. Polystyrene remains the

Spiro D. Alexandratos; Darrell W. Crick

1996-01-01

326

Molecular engineering of organic reagents and catalysts using soluble polymers  

Microsoft Academic Search

The separation of the final product of a reaction from byproducts, catalysts, or excess reagents is a process common to all synthetic procedures. Various methods to facilitate such separations continue to receive increasing attention as avenues to refine synthetic protocols. This review discusses recent developments in one of these areas, the use of soluble polymers as supports for organic synthesis

Philip L Osburn; David E Bergbreiter

2001-01-01

327

Homogeneous polynucleotide displacement assay method kit and reagent complex  

SciTech Connect

A method is described for determining the presence of a predetermined target nucleotide sequence in the DNA of a biological sample which comprises the steps: (a) providing a reagent complex of (i) a probe polynucleotide which is capable of base pair binding via hydrogen bonds of purine/pyrimidine bases to the DNA target nucleotide sequence, and (ii) an RNA signal strand polynucleotide which is bound by base pair binding via hydrogen bonds of purine/pyrimidine base pairs to the probe polynucleotide in a region of the probe polynucleotide at least partially coextensive with the region in which the probe polynucleotide is capable of binding to the DNA target nucleotide sequence; (b) contacting the reagent complex with a sample under conditions in which the DNA target nucleotide sequence, if present, binds to the probe polynucleotide and displaces the RNA signal strand polynucleotide from the reagent complex; (c) without separation, digesting the displaced RNA signal strand polynucleotide selectively with respect to RNA signal strand polynucleotide remaining in reagent complex; and (d) detecting the presence of the digestion products of digesting the displaced RNA signal strand polynucleotide.

Vary, C.P.H.

1989-01-03

328

CPTC expand scope of Reagents and Resources Core  

Cancer.gov

Whether in determining if a women is pregnant or not by measuring human chorionic gonadotropin or determining whether someone is HIV positive, antibodies and other affinity reagents play a key role both in diagnostic decision making and advancing the research field.

329

Methods and reagents. Reducing background colonies with positive selection vectors.  

PubMed

Methods and reagents is a unique monthly column that highlights current discussions in the newsgroup bionet.molbio.methds-reagnts, available on the Internet. This month's column discusses the pros and cons of eliminating unwanted background colonies by using the positive selection vector pZErO. For details on how to partake in the newsgroup, see the accompanying box. PMID:9066262

Hengen, P N

1997-03-01

330

Heterobifunctional reagents: A new approach to radiolabeling of monoclonal antibodies  

Microsoft Academic Search

The use of bifunctional chelate such as the cyclic anhydride of DTPA for radiolabeling antibodies (Abs) may lead to homopolymerization, and intra- or intermolecular cross-linking, with resulting denaturation and decrease immunoreactivity of Abs. The authors, therefore, investigated the use of heterobifunctional reagents, whereby one group selectively couples to the amino group of the Ab and the other group to the

T. S. T. Wang; A. K. Ng; R. A. Fawwaz; Z. Liu; P. O. Alderson

1985-01-01

331

Hypersensitivity pneumonitis in a technician using Pauli's reagent  

Microsoft Academic Search

A technician working in a medical laboratory used a spray of sodium diazobenzenesulphate (Pauli's reagent) in chromatography. She developed a respiratory illness with both airways obstruction and radiographic and physiological evidence of interstitial pneumonitis. An occupational type of challenge test was followed by both immediate and late bronchial obstructive responses, by a fall in arterial oxygen tension, and by increased

W V Evans; A Seaton

1979-01-01

332

Nucleophilic substitution by grignard reagents on sulfur mustards.  

PubMed

With proper activation of the leaving group, sulfur mustards react with Grignard reagents with neighboring group participation of the sulfur atom. 2,6-Dichloro-9-thiabicyclo[3.3.1]nonane is especially useful in this regard, providing clean reactivity with organomagnesium nucleophiles on a topologically constrained scaffold. PMID:15471488

Converso, Antonella; Saaidi, Pierre-Loïc; Sharpless, K Barry; Finn, M G

2004-10-15

333

[Recommendations for the control of equipment, reagents and consumables].  

PubMed

This article describes the dispositions to apply according to the requirements of the EN ISO 15189 standard for selection, purchasing and management of equipment, reagents and consumables in the medical laboratory. Recommendations are developed for acceptance testing, calibration and metrological traceability, maintenance and repair, adverse incident reporting and records to keep. PMID:23765022

Daunizeau, A

2013-06-01

334

Copper-catalysed ?-selective allylic alkylation of heteroaryllithium reagents.  

PubMed

2-Allyl-substituted thiophenes and furans are synthesised efficiently in a direct procedure using 2-heteroaryllithium reagents and allyl bromides and chlorides catalysed by ligand-free copper(i). The reactions take place under mild conditions, with excellent ?-selectivity, high functional group tolerance and good yields for the SN2 products. PMID:25334058

Vila, Carlos; Hornillos, Valentín; Fañanás-Mastral, Martín; Feringa, Ben L

2014-12-14

335

Finding new equilibria: Directed synthesis of lanthanide materials via sodium azide mediated pathways  

NASA Astrophysics Data System (ADS)

This dissertation covers the synthesis and characterization of three unique classes of lanthanide materials produced exclusively by the addition of sodium azide (NaN3) into solution based lanthanide reactions. The products were achieved through transmetallation and redox reactions between rare earth chalcogenolate reagents (Lnx(EPh)y), NaN 3 and elemental chalcogenides (E = O, S, Se, Te). The products displayed atypical structural and physical properties including; unique coordination geometries, high nuclearities, tunable detonation/deflagration, strong NIR emissions, and unexpected magnetic ordering behaviors. The introduction of NaN3, Na2O, Cd, elemental Se and Te into Ln (EPh)2 and Ln(EPh)3 pyridine (py) solutions led to the production of (py) 2Na2(EPh)2 and 5 structurally distinct azide encapsulated rare earth clusters; (Py) 10Sm6O2(N3)16Na2, (py)8Ln6O2(N3)12(SePh) 2, (py)10Ln6O2(Se2) 2(N3)10 (Ln=Er, Ho), and (py)16Sm 8Se(O2)Na2(Te2)6(N 3)8. Each system was encapsulated by a variety of azide bridging moieties, while exhibiting a [Ln]/[N3] dependent correlation with detonation and deflagration temperatures. The inclusion of NaN3 in Ln(SePh)3 pyridine solutions with elemental Se, led to the discovery of the (py)16Ln17 NaSe18(SePh)16; (Ln= Ce, Pr, and Nd). Emission studies of the Nd17 analogue, revealed a 35% quantum efficiency for the 4F3/2 - 4I11/2 transition (1070 nm emission), and a near solid state emission intensity for the 4F3/2 ? 4I15/2 transition (1822 nm emission). The novel Eu(EPh)4Na2•2DME; (E=S,Se), specimens were synthesized by the combination of Eu(EPh)2 with NaN3 in dimethoxyethane (DME). The europium coordination sphere was solvent free and resembles the coordinations of europium monochalcogenides (EuE). Comparative structural analysis and magnetic susceptibility studies of the Eu3+ product, ((py)6Eu2(mu4-S 2)2(OC6F5)2) revealed paramagnetic ordering at low temperature for Eu(EPh)4Na2•2DME; (E=S,Se), while ferrimagnetic ordering was found for ((py)6Eu2(mu4-S 2)2(OC6F5)2). All materials exhibited antiferromagnetic ordering above 50 K, while a Curie temperature of 18.0 K was determined for ((py)6Eu2(mu2-S 2)2-(OC6F5)2).

Moore, Brian Freeman

336

Thermodynamics and extraction modeling of trivalent lanthanides in the nuclear fuel cycle  

SciTech Connect

In this investigation, a combination of VPO (Vapor Pressure Osmometry) and water activity methods was applied to measure water activity and osmotic coefficients of binary lanthanide nitrate solutions at a temperature of 25 C. degrees. It was observed that the nature of the lanthanide nitrate has pronounced effect on the water activity in solution. In the solutions with the same Ln(NO{sub 3}){sub 3} molality, water activity is decreased in the order from the light to heavy lanthanides. This trend was explained by the contraction of the lanthanide ionic radii in the same order resulting in the [Ln(H{sub 2}O){sub n}]{sup 3+} (aq) hydration number of 9 for the early (La-Sm) and 8 for the late (Dy-Lu) lanthanides, with the intermediate metals exhibiting a mixture of eight and nine coordinate molecules. This results in the dissimilar effect of the light and heavy lanthanides on the water structure manifesting in the systematic changes of the water activity in the series of concentrated lanthanide solutions. Experimental water activity and osmotic coefficient data agree well with the literature for both 1:1 and 3:1 electrolyte systems. The Pitzer parameters obtained fitting these data are in an excellent agreement with the literature reported values for Ln(NO{sub 3}){sub 3} solutions.

Levitskaia, T.G.; Chatterjee, S.; Valerio, E.L.; Robinson, T.A. [Pacific Northwest National Laboratory, 902 Battelle Blvd, PO Box 999, MSIN P7-25 Richland, WA 99352 (United States)

2013-07-01

337

Design and synthesis of chelating diamide sorbents for the separation of lanthanides  

SciTech Connect

A nanoporous sorbent designed around chelating iminodiacetamide (“IDA-Amide”) moiety was made on mesoporous silica (MCM-41) and evaluated for lanthanide separations (Ce3+, Nd3+, Eu3+, Gd3+, and Lu3+). The effects of solution pH on lanthanide binding were studied, as well as sorption kinetics, and competition from other metal ions. The IDA-Amide SAMMS® demonstrated an interesting difference in the kinetics of sorption of the lanthanide ions in the order of Lu3+ > Eu3+ > Gd3+ > Nd3+ > Ce3+ . The close proximity of the ligands in the IDA-Amide SAMMS® may allow for multiple metal-ligand interactions (“macromolecular chelation”).

Fryxell, Glen E.; Chouyyok, Wilaiwan; Rutledge, Ryan D.

2011-06-01

338

Lanthanide Triflate-Catalyzed Carbon-Carbon Bond-Forming Reactions in Organic Synthesis  

Microsoft Academic Search

Versatile carbon-carbon bond-forming reactions using lanthanide triflates (Ln(OTf)3) as catalysts are discussed. Lanthanide triflates are new types of Lewis acids different from typical Lewis acids such as\\u000a AlCl3, BF3, SnCl4, etc. While most Lewis acids are decomposed or deactivated in the presence of water, lanthanide triflates are stable and\\u000a works as Lewis acids in water solutions. Many nitrogen-containing compounds such

Sh? Kobayashi

339

Dynamic Measurements of Aqueous Lanthanide Triflate-Catalyzed Reactions Using Luminescence Decay  

PubMed Central

There is tremendous interest in water-compatible lanthanide triflate-based catalysts for carbon–carbon bond forming reactions; however, poor understanding of their aqueous mechanism severely limits the ability to increase the utility of these catalysts. Here, we report dynamic measurements of the water-coordination number of lanthanide triflate-based catalysts using luminescence-decay measurements in a range of aqueous systems. This unique characterization method is a reliable, convenient, and fast approach to analyze lanthanide-based catalysts in aqueous systems. PMID:19385628

Dissanayake, Prabani; Allen, Matthew J.

2009-01-01

340

Stabilization of actinides and lanthanides in unusually high oxidation states  

SciTech Connect

Chemical environments can be chosen which stabilize actinides and lanthanides in unusually high or low oxidation states and in unusual coordination. In many cases, one can rationalize the observed species as resulting from strong charge/size influences provided by specific sites in host lattices (e.g., Tb(IV) in BaTbO/sub 3/ or Am(IV) in polytungstate anions). In other cases, the unusual species can be considered from an acid-base viewpoint (e.g., U(III) in AsF/sub 5//HF solution or Pu(VII) in Li/sub 5/PuO/sub 6/). In still other cases, an interplay of steric and redox effects can lead to interesting comparisons (e.g., instability of double fluoride salts of Pu(V) and Pu(VI) relative to U, Np, and Am analogues). Generalized ways to rationalize compounds containing actinides and lanthanides in unusual valences (particularly high valences), including the above and numerous other examples, will form the focus of this paper. Recently developed methods for synthesizing high valent f-element fluorides using superoxidizers and superacids at low temperatures will also be described. 65 refs., 8 figs., 9 tabs.

Eller, P.G.; Penneman, R.A.

1986-01-01

341

Purification of lanthanides for double beta decay experiments  

SciTech Connect

There are several potentially double beta active isotopes among the lanthanide elements. However, even high purity grade lanthanide compounds contain {sup 238}U, {sup 226}Ra and {sup 232,228}Th typically on the level of ? (0.1 - 1) Bq/kg. The liquid-liquid extraction technique was used to remove traces of U, Ra and Th from CeO{sub 2}, Nd{sub 2}O{sub 3} and Gd{sub 2}O{sub 3}. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe ? spectrometry at the underground Gran Sasso National Laboratories of the INFN (Italy). After the purification the radioactive contamination of gadolinium oxide by Ra and Th was decreased at least one order of magnitude. The efficiency of the approach to purify cerium oxide from Ra was on same level, while the radioactive contamination of neodymium sample before and after the purification is below the sensitivity of analytical methods. The purification method is much less efficient for chemically very similar radioactive elements like lanthanum, lutetium and actinium. R and D of the methods to remove the pollutions with improved efficiency is in progress.

Polischuk, O. G. [Institute for Nuclear Research, MSP 03680 Kyiv, Ukraine and INFN, Section of Rome, La Sapienza, I-00185 Rome (Italy)] [Institute for Nuclear Research, MSP 03680 Kyiv, Ukraine and INFN, Section of Rome, La Sapienza, I-00185 Rome (Italy); Barabash, A. S. [Institute of Theoretical and Experimental Physics, 117259 Moscow (Russian Federation)] [Institute of Theoretical and Experimental Physics, 117259 Moscow (Russian Federation); Belli, P. [INFN, Section of Rome Tor Vergata, I-00133 Rome (Italy)] [INFN, Section of Rome Tor Vergata, I-00133 Rome (Italy); Bernabei, R. [INFN, Section of Rome Tor Vergata, I-00133 Rome, Italy and Department of Physics, University of Rome Tor Vergata, I-00133 Rome (Italy)] [INFN, Section of Rome Tor Vergata, I-00133 Rome, Italy and Department of Physics, University of Rome Tor Vergata, I-00133 Rome (Italy); Boiko, R. S.; Danevich, F. A.; Mokina, V. M.; Poda, D. V.; Tretyak, V. I. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine)] [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Cappella, F.; Incicchitti, A. [INFN, Section of Rome La Sapienza, I-00185 Rome, Italy and Department of Physics, University of Rome La Sapienza, I-00185 Rome (Italy)] [INFN, Section of Rome La Sapienza, I-00185 Rome, Italy and Department of Physics, University of Rome La Sapienza, I-00185 Rome (Italy); Cerulli, R.; Laubenstein, M.; Nisi, S. [INFN, Gran Sasso National Laboratories, I-67100 Assergi (Aq) (Italy)] [INFN, Gran Sasso National Laboratories, I-67100 Assergi (Aq) (Italy)

2013-08-08

342

Energetic lanthanide complexes: coordination chemistry and explosives applications  

NASA Astrophysics Data System (ADS)

Metals are generally added to organic molecular explosives in a heterogeneous composite to improve overall heat and energy release. In order to avoid creating a mixture that can vary in homogeneity, energetic organic molecules can be directly bonded to high molecular weight metals, forming a single metal complex with Angstrom-scale separation between the metal and the explosive. To probe the relationship between the structural properties of metal complexes and explosive performance, a new series of energetic lanthanide complexes has been prepared using energetic ligands such as NTO (5-nitro-2,4-dihydro-1,2,4-triazole-3-one). These are the first examples of lanthanide NTO complexes where no water is coordinated to the metal, demonstrating novel control of the coordination environment. The complexes have been characterized by X-ray crystallography, NMR and IR spectroscopies, photoluminescence, and sensitivity testing. The structural and energetic properties are discussed in the context of enhanced blast effects and detection. Cheetah calculations have been performed to fine-tune physical properties, creating a systematic method for producing explosives with 'tailor made' characteristics. These new complexes will be benchmarks for further study in the field of metalized high explosives.

Manner, V. W.; Barker, B. J.; Sanders, V. E.; Laintz, K. E.; Scott, B. L.; Preston, D. N.; Sandstrom, M.; Reardon, B. L.

2014-05-01

343

Facile sonochemical synthesis and photoluminescent properties of lanthanide orthophosphate nanoparticles  

NASA Astrophysics Data System (ADS)

Uniform lanthanide orthophosphate LnPO 4 ( Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho) nanoparticles have been systematically synthesized via a facile, fast, efficient ultrasonic irradiation of inorganic salt aqueous solution under ambient conditions without any surfactant or template. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), photoluminescence (PL) spectra as well as kinetic decays were employed to characterize the samples. The SEM and the TEM images show that the hexagonal structured lanthanide orthophosphate LnPO 4 ( Ln=La, Ce, Pr, Nd, Sm, Eu, Gd) products have nanorod bundles morphology, while the tetragonal LnPO 4 ( Ln=Tb, Dy, Ho) samples prepared under the same experimental conditions are composed of nanoparticles. HRTEM micrographs and SAED results prove that these nanostructures are polycrystalline in nature. The possible formation mechanism for LnPO 4 ( Ln=La-Gd) nanorod bundles is proposed. Eu 3+-doped LaPO 4 and Tb 3+-doped CePO 4 samples were also prepared by using the same synthetic process, which exhibit an orange-red (Eu 3+: 5D 0- 7F 1, 2, 3, 4) and green (Tb 3+, 5D 4- 7F 3, 4, 5, 6) emission, respectively.

Yu, Cuicui; Yu, Min; Li, Chunxia; Liu, Xiaoming; Yang, Jun; Yang, Piaoping; Lin, Jun

2009-02-01

344

Protein Chemical Shift Prediction  

E-print Network

The protein chemical shifts holds a large amount of information about the 3-dimensional structure of the protein. A number of chemical shift predictors based on the relationship between structures resolved with X-ray crystallography and the corresponding experimental chemical shifts have been developed. These empirical predictors are very accurate on X-ray structures but tends to be insensitive to small structural changes. To overcome this limitation it has been suggested to make chemical shift predictors based on quantum mechanical(QM) calculations. In this thesis the development of the QM derived chemical shift predictor Procs14 is presented. Procs14 is based on 2.35 million density functional theory(DFT) calculations on tripeptides and contains corrections for hydrogen bonding, ring current and the effect of the previous and following residue. Procs14 is capable at performing predictions for the 13CA, 13CB, 13CO, 15NH, 1HN and 1HA backbone atoms. In order to benchmark Procs14, a number of QM NMR calculatio...

Larsen, Anders S

2014-01-01

345

Thermochromic Shifts in Supercritical Fluids.  

National Technical Information Service (NTIS)

Thermochromic shifts of organic solute molecules in supercritical Co2 under conditions of both constant pressure and density are compared to previous studies of solvatochromic shifts at isothermal conditions. Similar solvatochromic and thermochromic shift...

C. R. Yonker, R. D. Smith

1989-01-01

346

Shifts that divide populations  

NASA Astrophysics Data System (ADS)

If fitness landscape is non-concave, And the shift is wide, Then there is a good chance That population would divide. How does a population of organisms in an ecosystem respond to shifts in the environment? Answers to this question are critical to our understanding of the ecosystem and thus ability to manage it toward more desirable outcomes. We have developed a model of adaptation, based on replicator dynamics, in which we derive a simple but insightful threshold condition that separates two important types of responses: 'cohesive transition' in which the whole population changes gradually together, and 'population-dividing transition' in which the population splits into two groups with one eventually dominating the other. The threshold depends on the magnitude of the shift and the shape of the fitness landscape. Division in populations can fundamentally alter the functioning of the system; knowing the condition that gives rise to such division is thus fundamentally important.

Muneepeerakul, R.; Qubbaj, M. R.; Aggarwal, R.; Anderies, J. M.; Janssen, M. A.

2013-12-01

347

21 CFR 866.3390 - Neisseria spp. direct serological test reagents.  

Code of Federal Regulations, 2010 CFR

...spp. from cultured isolates. Additionally, some of these reagents consist of Neisseria spp. antisera conjugated with a fluorescent dye (immunofluorescent reagents) which may be used to detect the presence of Neisseria spp. directly from...

2010-04-01

348

A New Spray Reagent for Paper Chromatography of Polyols and Cetoses  

Microsoft Academic Search

VARIOUS reagents for indicating polyols in paper chromatography have been proposed by Hough, Buchanan et al. and Hockenhull1. These reagents all have the disadvantage of reacting also with the sugars, not distinguishing them from the polyols.

Paul Godin

1954-01-01

349

Manufacturing of lab-on-a-chip devices : characterizing seals for on-board reagent delivery  

E-print Network

The reagent delivery mechanism in a point-of-care, HIV diagnostic, microfluidic device is studied. Reagents held in an aluminum pack are released on the opening of a fluidic seal. Fluidic seals, controlling the flow of ...

Inamdar, Tejas Satish

2013-01-01

350

42 CFR 493.1252 - Standard: Test systems, equipment, instruments, reagents, materials, and supplies.  

Code of Federal Regulations, 2012 CFR

...results and test reports. (c) Reagents, solutions, culture media, control materials, calibration materials, and other...required for proper use. (d) Reagents, solutions, culture media, control materials, calibration materials, and...

2012-10-01

351

42 CFR 493.1252 - Standard: Test systems, equipment, instruments, reagents, materials, and supplies.  

Code of Federal Regulations, 2011 CFR

...results and test reports. (c) Reagents, solutions, culture media, control materials, calibration materials, and other...required for proper use. (d) Reagents, solutions, culture media, control materials, calibration materials, and...

2011-10-01

352

42 CFR 493.1252 - Standard: Test systems, equipment, instruments, reagents, materials, and supplies.  

Code of Federal Regulations, 2010 CFR

...results and test reports. (c) Reagents, solutions, culture media, control materials, calibration materials, and other...required for proper use. (d) Reagents, solutions, culture media, control materials, calibration materials, and...

2010-10-01

353

42 CFR 493.1252 - Standard: Test systems, equipment, instruments, reagents, materials, and supplies.  

Code of Federal Regulations, 2013 CFR

...results and test reports. (c) Reagents, solutions, culture media, control materials, calibration materials, and other...required for proper use. (d) Reagents, solutions, culture media, control materials, calibration materials, and...

2013-10-01

354

Cyanine dye labeling reagents--carboxymethylindocyanine succinimidyl esters.  

PubMed

Ten carboxymethylindocyanine dyes which form the basis of a new series of fluorescent probes have been synthesized and converted into succinimidyl active esters for fluorescent labeling of proteins or other amino-containing substances. Fluorescence emission maxima for members of the series range from 575 to 780 nm. Hydrophilic, water-soluble reagents have been obtained which yield labeled antibodies with little tendency to form precipitates. The fluorescence intensities achieved are higher than those produced by labeling with the cyanine isothiocyanates described previously (Mujumdar et al.: Cytometry 10:11-19, 1989). The utility of these reagents has been demonstrated in antibody labeling for two-color immunofluorescent imaging of internal structures in a mammalian cell and for two-color flow-cytometry experiments. The use of values of chromophore-equivalent weight (W/Ceq), calculated from quantitative absorption data on dye samples, is proposed as an aid in formulating labeling procedures. PMID:2340776

Southwick, P L; Ernst, L A; Tauriello, E W; Parker, S R; Mujumdar, R B; Mujumdar, S R; Clever, H A; Waggoner, A S

1990-01-01

355

21 CFR 864.9225 - Cell-freezing apparatus and reagents for in vitro diagnostic use.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Cell-freezing apparatus and reagents for...Blood and Blood Products § 864.9225 Cell-freezing apparatus and reagents for in...diagnostic use. (a) Identification. Cell-freezing apparatus and reagents...

2010-04-01

356

Adding reagent to droplets with controlled rupture of encapsulated double emulsions  

PubMed Central

We present a method to add reagent to microfluidic droplets by enveloping them as a double emulsions in reagent-filled droplets and then rupturing them with an electric field. When the double emulsions rupture, they release their contents into the enveloping droplets, ensuring mixing with reagent while limiting cross-droplet contamination. PMID:24404045

Sciambi, Adam; Abate, Adam R.

2013-01-01

357

21 CFR 864.9225 - Cell-freezing apparatus and reagents for in vitro diagnostic use.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Cell-freezing apparatus and reagents for...Blood and Blood Products § 864.9225 Cell-freezing apparatus and reagents for in...diagnostic use. (a) Identification. Cell-freezing apparatus and reagents...

2011-04-01

358

Total RNA extraction using Trizol reagent 1. Homogenization  

E-print Network

at 2 to 8°C. 5. REDISSOLVING THE RNA. At the end of the procedure, briefly dry the RNA pellet (air-dry exclusively in the aqueous phase. The volume of the aqueous phase is about 60% of the volume of TRIZOL Reagent or vacuum-dry for 5-10 minutes). Do not dry the RNA by centrifugation under vacuum. It is important

Oliver, Douglas L.

359

Reagent Selection Methodology for a Novel Explosives Detection Platform  

SciTech Connect

This video describes research being conducted by Dr. Marvin Warner, a research scientist at Pacific Northwest National Laboratory, in the individual pieces of antibodies used to set up a chemical reaction that will give off light just by mixing reagents together with a sample that contains an explosive molecule. This technology would help detect if explosives are present with just the use of a handheld system or container.

None

2010-06-01

360

Bedside shift-to-shift nursing report: implementation and outcomes.  

PubMed

One unit's staff developed and evaluated an intervention to relocate shift-to-shift nursing report to the patient's bedside. Despite challenges related to privacy, distractions, and integration of nursing technicians to the change, bedside shift report reduced shift report times and improved nursing satisfaction. PMID:23243785

Evans, Deby; Grunawalt, Julie; McClish, Donna; Wood, Winnie; Friese, Christopher R

2012-01-01

361

Lanthanide-encoded Poly(styrene-co-methacrylic Acid) Microspheres: Synthesis and Characterization.  

E-print Network

??Lanthanide-encoded polystyrene-co-methacrylic acid (P(S-MAA)) microspheres with narrow size distributions were synthesized by two-stage dispersion polymerization. I examined how the amounts of methacrylic acid (MAA) and… (more)

Liang, Yi

2012-01-01

362

Engineering Encodable Lanthanide-Binding Tags (LBTs) into Loop Regions of Proteins  

E-print Network

Lanthanide-binding tags (LBTs) are valuable tools for investigation of protein structure, function, and dynamics by NMR spectroscopy, X-ray crystallography, and luminescence studies. We have inserted LBTs into three different ...

Barthelmes, Katja

363

Study of lanthanide doped zinc oxide nanoparticles synthesized via a sonochemical method  

NASA Astrophysics Data System (ADS)

In this work, lanthanide doped zinc oxide nanoparticles synthesized in room-temperature ionic liquid via a sonochemical method have been studied. Firstly, the cavitation bubble temperatures in 1-butyl-3-methylimidazolium hexafluorophosphate (ImPF6) have been estimated by the methyl radical recombination method. The temperatures measured in ImPF6 are in the range of 3000-4000 K. Secondly, a facile method has been proposed to prepare lanthanide (III) doped zinc oxide nanoparticles in ImPF6 via an ultrasonic irradiation. The nanomaterials are studied by transmission electron microscopy, X-ray diffraction, photoacoustic and luminescence techniques. The results show that the relaxation processes of the samples depend strongly on the lanthanide doping. Moreover, a mechanism is proposed to interpret the formation of lanthanide (III) doped zinc oxide nanoparticles in the ImPF6 upon ultrasonic irradiation.

Gao, Bin; Yang, YueTao; Yang, Hao; Zhang, ShuYi; Liu, XiaoJun

2013-07-01

364

Optical in situ size determination of single lanthanide-ion doped oxide nanoparticles  

E-print Network

within a few seconds in typical single-molecule experiments . Photostable nanocrystals, such as colloidal for lanthanide-doped oxide nano- particles based on the fact that the nanoparticle luminosity is proportional

Boyer, Edmond

365

IA PERIODIC TABLE OF THE ELEMENTS VillA lanthanide Series  

E-print Network

#12;IA PERIODIC TABLE OF THE ELEMENTS VillA lanthanide Series Actinide Series The elements highlighted in this table are some of the most common constituents of contaminant waste at DOE sites. #12;................................................................................................................................................. TABLE OF CONTENTS ACKNOWLEDGMENTS.. . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 FOREWORD

Hazen, Terry

366

One-pot synthesis of ?-amino esters from aldehydes using lanthanide triflate as a catalyst  

Microsoft Academic Search

One-pot synthesis of a ?-amino ester from an aldehyde, an amine, and a silyl enolate has been achieved using a lanthanide triflate as a catalyst. One-pot preparation of a ?-lactam from an aldehyde is also described.

Sh? Kobayashi; Mitsuharu Araki; Masaru Yasuda

1995-01-01

367

The TRUSPEAK Concept: Combining CMPO and HDEHP for Separating Trivalent Lanthanides from the Transuranic Elements  

SciTech Connect

Combining octyl(phenyl)-N,N-diisobutyl-carbamoylmethyl-phosphine oxide (CMPO) and bis-(2-ethylhexyl) phosphoric acid (HDEHP) into a single process solvent for separating transuranic elements from liquid high-level waste is explored. Co-extraction of americium and the lanthanide elements from nitric acid solution is possible with a solvent mixture consisting of 0.1-M CMPO plus 1-M HDEHP in n-dodecane. Switching the aqueous-phase chemistry to a citrate-buffered solution of diethylene triamine pentaacetic acid (DTPA) allows for selective stripping of americium, separating it from the lanthanide elements. Potential strategies for managing molybdenum and zirconium (both of which co-extract with americium and the lanthanides) have been developed. The work presented here demonstrates the feasibility of combining CMPO and HDEHP into a single extraction solvent for recovering americium from high-level waste and its separation from the lanthanides.

Lumetta, Gregg J.; Gelis, Artem V.; Braley, Jenifer C.; Carter, Jennifer C.; Pittman, Jonathan W.; Warner, Marvin G.; Vandegrift, George F.

2013-04-08

368

NOVEL APPROACH TO METAL-HUMIC COMPLEXATION STUDIES BY LANTHANID ION PROBE SPECTROSCOPY  

EPA Science Inventory

Naturally occurring humic substances are known to be potentially strong binders of metals in the environment. ensitive spectroscopic technique, based on the unique luminescence properties of the tripositive lanthanide metal ions, has been developed to selectively probe metal bind...

369

Pilot-Scale TRUEX Flowsheet Testing for Separation of Actinides and Lanthanides from Used Nuclear Fuel  

SciTech Connect

Advanced aqueous separation processes are being developed for the recycling of used nuclear fuel as part of the U.S. Department of Energy Nuclear Energy Advanced Fuel Cycle Initiative. The Transuranic Extraction (TRUEX) Process is being developed as part of these advanced separations processes for the separation of actinides and lanthanides from the used nuclear fuel. Testing of a TRUEX flowsheet has been performed using a thirty stage, 5-cm centrifugal contactor pilot plant. This testing was performed using a non-radioactive feed surrogate and data were collected and analyzed to evaluate removal efficiencies of the lanthanides, mass transfer efficiency of the lanthanides in the extraction and strip sections of the flowsheet, and the temperature profile of the process solutions throughout the centrifugal contactor pilot plant. Results indicate >99.9% separation for all lanthanides and mass transfer efficiencies typically ranging from 85% to 100%. Solution temperatures for each contactor stage, as well as general process performance, are also described.

Jack D. Law; Troy G. Garn; David H. Meikrantz; Jamie Warburton

2010-01-01

370

Lanthanide-Mediated Dephosphorylation Used for Peptide Cleavage during Solid Phase Peptide Synthesis  

PubMed Central

Lanthanide(III) ions can accelerate the hydrolysis of phosphomonoesters and phosphodiesters in neutral aqueous solution. In this paper, lanthanide-mediated dephosphorylation has been applied in aqueous media as an orthogonal cleavage condition that can be employed in conventional solid phase peptide synthesis (SPPS). A phosphorylated polymeric support for SPPS was developed using Boc chemistry. The cleavage of resin-bound phosphates was investigated with the addition of Eu(III), Yb(III), acid or base, a mixture of solvents or different temperatures. To demonstrate the utility of this approach for SPPS, a peptide sequence was synthesized on a phosphorylated polymeric support and quantitatively cleaved with lanthanide ions in neutral aqueous media. The protecting groups for side chains were retained during peptide cleavage using lanthanide ions. This new methodology provides a mild orthogonal cleavage condition of phosphoester as a linker during SPPS. PMID:23549296

Yoo, Byunghee; Pagel, Mark D.

2014-01-01

371

Proton Chemical Shifts  

NSDL National Science Digital Library

Created by Hans Reich, professor of organic chemistry at the Uiversity of Wisconsin-Madison, this site contains a compilation of proton chemical shifts and coupling constants. This is an excellent resource for providing students familiarity with Nuclear Magnetic Resonance (NMR) Spectroscopy Data.

Reich, Hans J.

2007-11-16

372

Aptamers and the Next Generation of Diagnostic Reagents  

PubMed Central

Antibodies have been extensively used as capture and detection reagents in diagnostic applications of proteomics-based technologies. Proteomic assays need high sensitivity and specificity, a wide dynamic range for detection, and accurate, reproducible quantification with small confidence values. However, several inherent limitations of monoclonal antibodies in meeting the emerging challenges of proteomics led to the development of a new class of oligonucleotide-based reagents. Natural and derivatized nucleic acid aptamers are emerging as promising alternatives to monoclonal antibodies. Aptamers can be effectively used to simultaneously detect thousands of proteins in multiplex discovery platforms, where antibodies often fail due to cross-reactivity problems. Through chemical modification, vast range of additional functional groups can be added at any desired position in the oligonucleotide sequence, therefore the best features of small molecule drugs, proteins and antibodies can be brought together into aptamers, making aptamers the most versatile reagent in proteomics. In this review we discuss the recent developments in aptamer technology, including new selection methods and the aptamers’ application in proteomics. PMID:23090891

Thiviyanathan, Varatharasa; Gorenstein, David G.

2014-01-01

373

UV Decontamination of MDA Reagents for Single Cell Genomics  

SciTech Connect

Single cell genomics, the amplification and sequencing of genomes from single cells, can provide a glimpse into the genetic make-up and thus life style of the vast majority of uncultured microbial cells, making it an immensely powerful and increasingly popular tool. This is accomplished by use of multiple displacement amplification (MDA), which can generate billions of copies of a single bacterial genome producing microgram-range DNA required for shotgun sequencing. Here, we address a key challenge inherent to this approach and propose a solution for the improved recovery of single cell genomes. While DNA-free reagents for the amplification of a single cell genome are a prerequisite for successful single cell sequencing and analysis, DNA contamination has been detected in various reagents, which poses a considerable challenge. Our study demonstrates the effect of UV irradiation in efficient elimination of exogenous contaminant DNA found in MDA reagents, while maintaining Phi29 activity. Consequently, we also find that increased UV exposure to Phi29 does not adversely affect genome coverage of MDA amplified single cells. While additional challenges in single cell genomics remain to be resolved, the proposed methodology is relatively quick and simple and we believe that its application will be of high value for future single cell sequencing projects.

Lee, Janey; Tighe, Damon; Sczyrba, Alexander; Malmatrom, Rex; Clingenpeel, Scott; Malfatti, Stephanie; Rinke, Christian; Wang, Zhong; Stepanauskas, Ramunas; Cheng, Jan-Fang; Woyke, Tanja

2011-03-18

374

Sulfhydryl reagents and energy-linked reactions in monocot thylakoids.  

PubMed

Monofunctional maleimides have been used to covalently modify the coupling factor protein of monocot thylakoid membranes. As with dicot thylakoids, incubation of the monocot thylakoids with maleimides in the light but not in the dark results in inhibition of both ATP synthesis and hydrolysis. In the dark, sites on the gamma and epsilon subunits of maize Zea mays coupling factor 1 are modified after incubation of maize mesophyll thylakoids with the fluorescent maleimide N-(anilinonaphthyl-4) maleimide. A light accessible site localized solely to the gamma subunit has also been demonstrated. In contrast to the case with dicot thylakoids (spinach [Spinacia oleracea] and pea [Pisum sativum]) treatment of monocot thylakoids (maize, barley [Hordeum vulgare], crabgrass [Digitaria sanguinalis]) with bifunctional maleimides or thiol oxidants in the light does not result in functional uncoupling, i.e the bifunctional reagents act more like energy transfer inhibitors. The lack of functional uncoupling could be due either to a failure of the reagents to cross-link key sulfhydryl residues in the gamma subunit or to the continued ability of the gamma subunit to gate proton movements through the chloroplast coupling factor complex even though its conformation has been altered by sulfhydryl reagents. PMID:16667548

Cohen, W S; Baxter, D R

1990-07-01

375

Magnetic anisotropy in the excited states of low symmetry lanthanide complexes.  

PubMed

Ab initio investigation of multiplet spectrum of lanthanides in archetypal coordination geometries shows an unexpected regular structure consisting of (i) mirror symmetry of anisotropic magnetic properties of doublet states, (ii) high magnetic axiality of low-lying and high-lying doublets, comparable to complexes with ideal axial symmetry, and (iii) the strong rotation of the anisotropy axes of individual doublets. The obtained high axiality of the ground doublet states explains the SMM behaviour of low-symmetry lanthanide complexes. PMID:22027865

Ungur, Liviu; Chibotaru, Liviu F

2011-12-01

376

Environmental fate and ecotoxicity of lanthanides: are they a uniform group beyond chemistry?  

PubMed

Lanthanides are a chemically uniform group of metals (La-Lu) that, together with yttrium (Y) and scandium (Sc), form the group of rare earth elements (REEs). Because of their many applications (e.g., agriculture, medicine, motor industry), their global production has increased exponentially in the last decades and their biogeochemical cycles are being disrupted by human uses (e.g., gadolinium anomalies in freshwater and tap water, REEs enrichment of soils as a consequence of agricultural practices). However, ecotoxicological effects and mechanism of action of these elements are still poorly understood. In particular, there is no consensus as to lanthanides showing a coherent and predictable pattern of (eco)toxicity in the same way as their atomic properties. For aquatic organisms, contradictory conclusions on this issue can be found in the bibliography. This review shows that the variable composition of culture media used in ecotoxicology, and the associated differences in lanthanide's speciation, are the most likely cause for such discrepancies. In particular, the formation of insoluble species in some highly complexing media likely leads to changes in the soluble concentration of lanthanide during some tests; with the potential for a generalized underestimation of their toxicity at the present state of knowledge. For terrestrial organisms, suitable studies to establish trends in lanthanides' toxicity are practically nonexistent; with most research focusing on the effects of REE mixtures. Molecular level studies to elucidate the mechanisms of action of lanthanides are essentially limited to La, pointing to the need for further research to identify common mechanisms of action or modes of action across lanthanides. Overall, agreement on the correct procedures to follow to obtain reliable and comparable data for individual lanthanide is the first action to take in order to arrive at a reliable risk assessment for this group of elements in both aquatic and terrestrial systems. PMID:25036616

Gonzalez, Veronica; Vignati, Davide A L; Leyval, Corinne; Giamberini, Laure

2014-10-01

377

The kinetics of lanthanide complexation by EDTA and DTPA in lactate media.  

PubMed

The interaction of trivalent lanthanide and actinide cations with polyaminopolycarboxylic acid complexing agents in lactic acid buffer systems is an important feature of the chemistry of the TALSPEAK process for the separation of trivalent actinides from lanthanides. To improve understanding of metal ion coordination chemistry in this process, the results of an investigation of the kinetics of lanthanide complexation by ethylenediamine-N,N,N',N'-tetraacetic acid (EDTA) and diethylenetriamine-N,N,N',N'',N''-pentaacetic acid (DTPA) in 0.3 M lactic acid/0.3 M ionic strength solution are reported. Progress of the reaction was monitored using the distinctive visible spectral changes attendant to lanthanide complexation by the colorimetric indicator ligand Arsenazo III, which enables the experiment but plays no mechanistic role. Under the conditions of these experiments, the reactions occur in a time regime suitable for study by stopped-flow spectrophotometric techniques. Experiments have been conducted as a function of EDTA/DTPA ligand concentration, total lactic acid concentration, and pH. The equilibrium perturbation reaction proceeds as a first order approach to equilibrium over a wide range of conditions, allowing the simultaneous determination of complex formation and dissociation rate constants. The rate of the complexation reaction has been determined for the entire lanthanide series (except Pm(3+)). The predominant pathway for lanthanide-EDTA and lanthanide-DTPA dissociation is inversely dependent on the total lactate concentration; the complex formation reaction demonstrates a direct dependence on [H(+)]. Unexpectedly, the rate of the complex formation reaction is seen in both ligand systems to be fastest for Gd(3+). Correlation of these results indicates that in 0.3 M lactate solutions the exchange of lanthanide ions between lactate complexes and the polyaminopolycarboxylate govern the process. PMID:23080218

Nash, K L; Brigham, D; Shehee, T C; Martin, A

2012-12-28

378

Key features of the Talspeak and similar trivalent actinide-lanthanide partitioning processes  

SciTech Connect

As closing of the nuclear-fuel cycle via the suite of UREX processes under development in the U.S. progresses, the Trivalent Actinide-Lanthanide Separation by Phosphorus Extractants and Aqueous Komplexants (TALSPEAK) process has been selected as the baseline process for partition of trivalent actinides away from fission-product lanthanides. In this report, selected features of the chemistry of the TALSPEAK process and the limited parallel information on other TALSPEAK-like processes are discussed. (author)

Nash, Kenneth L. [Washington State University, Chemistry Department, P.O. Box 644630, Pullman, WA 99164-4630 (United States)

2008-07-01

379

Nitrite-templated synthesis of lanthanide-containing [2]rotaxanes for anion sensing.  

PubMed

The first anion-templated synthesis of a lanthanide-containing interlocked molecule is demonstrated by utilizing a nitrite anion to template initial pseudorotaxane formation. Subsequent stoppering of the interpenetrated assembly allows for the preparation of a lanthanide-functionalized [2]rotaxane in high yield. Following removal of the nitrite anion template, the europium [2]rotaxane host is demonstrated to recognize and sense fluoride selectively. PMID:24989322

Langton, Matthew J; Blackburn, Octavia A; Lang, Thomas; Faulkner, Stephen; Beer, Paul D

2014-10-20

380

Formation and stability of lanthanide complexes and their encapsulation into polymeric microspheres  

SciTech Connect

The complexation of lanthanides (Ln) with dicarbonyl compounds (acetylacetone, acac; ethyl acetoacetate; 3-ethyl-2,4-pentanedione; 2,4-hexanedione; 3-methyl-2,4-pentanedione; and diethyl malonate) was investigated using a potentiometric titration technique. The ability of a dicarbonyl compound to complex with the lanthanide elements was greatly dependent on its pK{sub a} and on the pH of the titrated solution. Selected lanthanide complexes (Ln complexes) were incorporated into spherical poly(L-lactic acid)(PLA) matrices and irradiated in a nuclear reactor with neutrons to produce short-lived high-energy {Beta}-particle-emitting radioisotopes. The lanthanides investigated (Ho, Dy, Sm, and La) were chosen on the basis of their physical and nuclear properties. A transition element (Re) was also studied. The small decrease in the ionic radii of the lanthanides with increasing atomic number led to (a) greater ability to extract and complex from an aqueous solution with complexing agents, (b) larger formation and stability constants for the Ln complexes, (c) increased solubility of the Ln complexes in chloroform, and (d) increase in the maximum percent incorporation of the stable lanthanides in PLA spheres. Ho(aca) was found to be the most promising candidate of the complexes studied on the basis of the above observations and due to the favorable physical properties of {sup 165}Ho and nuclear properties of {sup 166}Ho. 21 refs., 5 figs., 4 tabs.

Mumper, R.J.; Jay, M. [Univ. of Kentucky, Lexington, KY (United States)

1992-10-15

381

Supramolecular luminescent lanthanide dimers for fluoride sequestering and sensing.  

PubMed

Lanthanide complexes (Ln=Eu, Tb, and Yb) that are based on a C2 -symmetric cyclen scaffold were prepared and characterized. The addition of fluoride anions to aqueous solutions of the complexes resulted in the formation of dinuclear supramolecular compounds in which the anion is confined into the cavity that is formed by the two complexes. The supramolecular assembly process was monitored by UV/Vis absorption, luminescence, and NMR spectroscopy and high-resolution mass spectrometry. The X-ray crystal structure of the europium dimer revealed that the architecture of the scaffold is stabilized by synergistic effects of the Eu?F?Eu bridging motive, ??stacking interactions, and a four-component hydrogen-bonding network, which control the assembly of the two [EuL] entities around the fluoride ion. The strong association in water allowed for the luminescence sensing of fluoride down to a detection limit of 24?nM. PMID:24909695

Liu, Tao; Nonat, Aline; Beyler, Maryline; Regueiro-Figueroa, Martín; Nchimi Nono, Katia; Jeannin, Olivier; Camerel, Franck; Debaene, François; Cianférani-Sanglier, Sarah; Tripier, Raphaël; Platas-Iglesias, Carlos; Charbonnière, Loïc J

2014-07-01

382

Thermodynamics of complexation of lanthanides by dicarboxylate ligands  

SciTech Connect

Thermodynamic parameters of complexation of lanthanide cations by succinate, glutarate, adipate, and trans-1,4-cyclohexane-dicarboxylate (CHDCA) ligands have been measured with potentiometric and calorimetric techniques. When analogous data for oxalate and malonate complexing are included, the complex stability decreases sharply as the ring size increases from 5 to 7; however, for 7-9-membered rings, there is little difference in stability. The negative entropy contribution associated with expansion in ring size has been attributed to an increasing loss in the configuration entropy in the alkyl chain. The more positive entropy for the Sm-CHDCA complex compared to that of Sm-adipate is attributed to the favorable boat configuration for chelation with CHDCA.

Choppin, G.R.; Dadgar, A.; Rizkalla, E.N.

1986-09-24

383

Gold Coated Lanthanide Phosphate Nanoparticles for Targeted Alpha Generator Radiotherapy  

SciTech Connect

Targeted radiotherapies maximize cytotoxicty to cancer cells. In vivo generators such as 225Ac, which emits four particles in its decay chain, can significantly amplify the radiation dose delivered to the target site. However, renal dose from unbound 213Bi escaping during the decay process limits the dose of 225Ac that can be administered. Traditional chelating moieties are unable to sequester the radioactive daughters because of the high recoil energy from alpha particle emission. To counter this, we demonstrate that an engineered multilayered nanoparticle-antibody conjugate can both deliver radiation and contain the decay daughters of the in vivo -generator 225Ac while targeting biologically relevant receptors. These multi-shell nanoparticles combine the radiation resistance of crystalline lanthanide phosphate to encapsulate and contain 225Ac and its radioactive decay daughters, the magnetic properties of gadolinium phosphate for easy separation, and established surface chemistry of gold for attachment of nanoparticles to targeting antibodies.

McLaughlin, Mark F [ORNL; Woodward, Jonathan [ORNL; Boll, Rose Ann [ORNL; Wall, Jonathan [University of Tennessee, Knoxville (UTK); Rondinone, Adam Justin [ORNL; Kennel, Steve J [ORNL; Mirzadeh, Saed [ORNL; Robertson, David J. [University of Missouri

2013-01-01

384

Gold coated lanthanide phosphate nanoparticles for targeted alpha generator radiotherapy.  

PubMed

Targeted radiotherapies maximize cytotoxicty to cancer cells. In vivo ?-generator targeted radiotherapies can deliver multiple ? particles to a receptor site dramatically amplifying the radiation dose delivered to the target. The major challenge with ?-generator radiotherapies is that traditional chelating moieties are unable to sequester the radioactive daughters in the bioconjugate which is critical to minimize toxicity to healthy, non-target tissue. The recoil energy of the (225)Ac daughters following ? decay will sever any metal-ligand bond used to form the bioconjugate. This work demonstrates that an engineered multilayered nanoparticle-antibody conjugate can deliver multiple ? radiations and contain the decay daughters of (225)Ac while targeting biologically relevant receptors in a female BALB/c mouse model. These multi-shell nanoparticles combine the radiation resistance of lanthanide phosphate to contain (225)Ac and its radioactive decay daughters, the magnetic properties of gadolinium phosphate for easy separation, and established gold chemistry for attachment of targeting moieties. PMID:23349921

McLaughlin, Mark F; Woodward, Jonathan; Boll, Rose A; Wall, Jonathan S; Rondinone, Adam J; Kennel, Stephen J; Mirzadeh, Saed; Robertson, J David

2013-01-01

385

Gold Coated Lanthanide Phosphate Nanoparticles for Targeted Alpha Generator Radiotherapy  

PubMed Central

Targeted radiotherapies maximize cytotoxicty to cancer cells. In vivo ?-generator targeted radiotherapies can deliver multiple ? particles to a receptor site dramatically amplifying the radiation dose delivered to the target. The major challenge with ?-generator radiotherapies is that traditional chelating moieties are unable to sequester the radioactive daughters in the bioconjugate which is critical to minimize toxicity to healthy, non-target tissue. The recoil energy of the 225Ac daughters following ? decay will sever any metal-ligand bond used to form the bioconjugate. This work demonstrates that an engineered multilayered nanoparticle-antibody conjugate can deliver multiple ? radiations and contain the decay daughters of 225Ac while targeting biologically relevant receptors in a female BALB/c mouse model. These multi-shell nanoparticles combine the radiation resistance of lanthanide phosphate to contain 225Ac and its radioactive decay daughters, the magnetic properties of gadolinium phosphate for easy separation, and established gold chemistry for attachment of targeting moieties. PMID:23349921

McLaughlin, Mark F.; Woodward, Jonathan; Boll, Rose A.; Wall, Jonathan S.; Rondinone, Adam J.; Kennel, Stephen J.; Mirzadeh, Saed; Robertson, J. David

2013-01-01

386

Lanthanides in molecular magnetism: old tools in a new field.  

PubMed

In this tutorial review we discuss some basic aspects concerning the magnetic properties of rare-earth ions, which are currently the subject of a renovated interest in the field of molecular magnetism, after the discovery that slow relaxation of the magnetization at liquid nitrogen temperature can occur in mononuclear complexes of these ions. Focusing on Dy(III) derivatives a tutorial discussion is given of the relation of the crystal field parameters, which determine the anisotropy of these systems and consequently their interesting magnetic properties, with the geometry of the coordination sphere around the lanthanide centre and with the pattern of f orbitals. The problem of systems of low point symmetry is also addressed by showing how detailed single crystal investigation, coupled to more sophisticated calculation procedures, is an absolute necessity to obtain meaningful structure-property relationships in these systems. PMID:21390351

Sorace, Lorenzo; Benelli, Cristiano; Gatteschi, Dante

2011-06-01

387

Shifts that divide population  

NASA Astrophysics Data System (ADS)

How does a population of organisms in an ecosystem or of people in a society respond to rapid shifts in the environment? Answers to this question are critical to our ability to anticipate and cope with a changing ecohydrological system. We have developed a generic model of adaptation mechanisms, based on replicator dynamics, in which we derive a simple and insightful threshold condition that separates two important types of responses: 'cohesive transition' in which the whole population changes gradually together, and 'population-dividing transition' in which the population splits into two groups with one eventually dominating the other. The threshold depends on the magnitude of the shift and the shape of the fitness landscape. Division in populations can fundamentally alter the functioning of and induce subsequent feedbacks within the system; knowing the condition that gives rise to such division is thus fundamentally important.

Muneepeerakul, Rachata; Qubbaj, Murad; Aggarwal, Rimjhim; Anderies, John M.; Janssen, Marco

2014-05-01

388

Ambiguous Red Shifts  

E-print Network

A one-parameter conformal invariance of Maxwell's equations allows the wavelengths of electromagnetic waves to change as they propagate, and do so even in otherwise field-free space. This produces an ambiguity in interpretations of stellar red shifts. Experiments that will determine the value of the group parameter, and thereby remove the ambiguity, are proposed. They are based on an analysis of the anomalous frequency shifts uncovered in the Pioneer 10 and 11 spacecraft studies, and physical interpretation of an isomorphism discovered by E. L. Hill. If the group parameter is found to be non-zero, Hubble's relations will have to be reinterpreted and space-time metrics will have to be altered. The cosmological consequences of the transformations are even more extensive because, though they change frequencies, they do not alter the energy and momentum conservations laws of classical and quantum-electrodynamical fields established by Cunningham and by Bialynicki-Birula.

Carl E. Wulfman

2010-10-11

389

Shifted reference holographic interferometry.  

PubMed

Conventional holographic interferometry of vibrating objects yields reconstructed images in which the radiance of each point is proportional to the square of the zero-order Bessel function of an argument proportional to the vibration amplitude. Therefore, the vibration pattern appears as a dark outline on the bright background of the nonvibrating points. By appropriately shifting the frequency of the reference radiation used in the recording of the hologram, the radiance of each image point can be made proportional to the square of the first-order Bessel function of the above argument. Nonvibrating points are therefore black and vibrating points appear bright on a black background. A quantitative analysis of the technique is reviewed and extended and shows the shifted-reference method to be almost one order of magnitude more sensitive than the conventional method. Experimental verification of the theory is presented and some possible future applications are indicated. PMID:20125577

Zambuto, M H; Fischer, W K

1973-07-01

390

Methods and apparatuses for reagent delivery, reactive barrier formation, and pest control  

DOEpatents

A reagent delivery method includes positioning reagent delivery tubes in contact with soil. The tubes can include a wall that is permeable to a soil-modifying reagent. The method further includes supplying the reagent in the tubes, diffusing the reagent through the permeable wall and into the soil, and chemically modifying a selected component of the soil using the reagent. The tubes can be in subsurface contact with soil, including groundwater, and can be placed with directional drilling equipment independent of groundwater well casings. The soil-modifying reagent includes a variety of gases, liquids, colloids, and adsorbents that may be reactive or non-reactive with soil components. The method may be used inter alia to form reactive barriers, control pests, and enhance soil nutrients for microbes and plants.

Gilmore, Tyler [Pasco, WA; Kaplan, Daniel I [Aiken, SC; Last, George [Richland, WA

2002-07-09

391

The shifting beverage landscape.  

PubMed

STOREY, M.L. The shifting beverage landscape. PHYSIOL BEHAV, 2010. - Simultaneous lifestyle changes have occurred in the last few decades, creating an imbalance in energy intake and energy expenditure that has led to overweight and obesity. Trends in the food supply show that total daily calories available per capita increased 28% since 1970. Total energy intake among men and women has also increased dramatically since that time. Some have suggested that intake of beverages has had a disproportional impact on obesity. Data collected by the Beverage Marketing Corporation between 1988-2008 demonstrate that, in reality, fewer calories per ounce are being produced by the beverage industry. Moreover, data from the National Cancer Institute show that soft drink intake represents 5.5% of daily calories. Data from NHANES 1999-2003 vs. 2003-06 may demonstrate a shift in beverage consumption for age/gender groups, ages 6 to>60years. The beverages provided in schools have significantly changed since 2006 when the beverage industry implemented School Beverage Guidelines. This voluntary action has removed full-calorie soft drinks from participating schools across the country. This shift to lower-calorie and smaller-portion beverages in school has led to a significant decrease in total beverage calories in schools. These data support the concept that to prevent and treat obesity, public health efforts should focus on energy balance and that a narrow focus on sweetened beverages is unlikely to have any meaningful impact on this complex problem. PMID:20188750

Storey, Maureen

2010-04-26

392

Application of selective F 1 decoupled 1H NMR for enantiomer resolution and accurate measurement of enantiomeric excess at low chiral substrate/auxiliary concentration  

NASA Astrophysics Data System (ADS)

The higher substrate and chiral auxiliary concentration is a pre-requisite to obtain efficient separation of 1H NMR signals of enantiomers. The higher concentration of chiral lanthanide shift reagents provides broadened spectral lines resulting in a severe loss of resolution between the enantiomer resonances. In order to circumvent such difficulties, herein we present the application and the usefulness of a selective F 1 decoupled correlation (COSY) experiment which yields proton decoupled proton spectra in the indirect dimension. The potentiality of the experiment is demonstrated on several chiral compounds possessing different functional groups, employing either a lanthanide shift reagent or a solvating reagent as chiral auxiliaries.

Nath, Nilamoni; Kumari, Divya; Suryaprakash, N.

2011-05-01

393

Chemical interaction matrix between reagents in a Purex based process  

SciTech Connect

The United States Department of Energy (DOE) is the responsible entity for the disposal of the United States excess weapons grade plutonium. DOE selected a PUREX-based process to convert plutonium to low-enriched mixed oxide fuel for use in commercial nuclear power plants. To initiate this process in the United States, a Mixed Oxide (MOX) Fuel Fabrication Facility (MFFF) is under construction and will be operated by Shaw AREVA MOX Services at the Savannah River Site. This facility will be licensed and regulated by the U.S. Nuclear Regulatory Commission (NRC). A PUREX process, similar to the one used at La Hague, France, will purify plutonium feedstock through solvent extraction. MFFF employs two major process operations to manufacture MOX fuel assemblies: (1) the Aqueous Polishing (AP) process to remove gallium and other impurities from plutonium feedstock and (2) the MOX fuel fabrication process (MP), which processes the oxides into pellets and manufactures the MOX fuel assemblies. The AP process consists of three major steps, dissolution, purification, and conversion, and is the center of the primary chemical processing. A study of process hazards controls has been initiated that will provide knowledge and protection against the chemical risks associated from mixing of reagents over the life time of the process. This paper presents a comprehensive chemical interaction matrix evaluation for the reagents used in the PUREX-based process. Chemical interaction matrix supplements the process conditions by providing a checklist of any potential inadvertent chemical reactions that may take place. It also identifies the chemical compatibility/incompatibility of the reagents if mixed by failure of operations or equipment within the process itself or mixed inadvertently by a technician in the laboratories. (aut0010ho.

Brahman, R.K.; Hennessy, W.P. [Shaw AREVA MOX Services, LLC (United States); Paviet-Hartmann, P. [Idaho State University/Idaho National Laboratory (United States)

2008-07-01

394

Desalting protein ions in native mass spectrometry using supercharging reagents.  

PubMed

Effects of the supercharging reagents m-NBA and sulfolane on sodium ion adduction to protein ions formed using native mass spectrometry were investigated. There is extensive sodium adduction on protein ions formed by electrospray ionization from aqueous solutions containing millimolar concentrations of NaCl, which can lower sensitivity by distributing the signal of a given charge state over multiple adducted ions and can reduce mass measuring accuracy for large proteins and non-covalent complexes for which individual adducts cannot be resolved. The average number of sodium ions adducted to the most abundant ion formed from ten small (8.6-29 kDa) proteins for which adducts can be resolved is reduced by 58% or 80% on average, respectively, when 1.5% m-NBA or 2.5% sulfolane are added to aqueous solutions containing sodium compared to without the supercharging reagent. Sulfolane is more effective than m-NBA at reducing sodium ion adduction and at preserving non-covalent protein-ligand and protein-protein interactions. Desalting with 2.5% sulfolane enables detection of several glycosylated forms of 79.7 kDa holo-transferrin and NADH bound to the 146 kDa homotetramer LDH, which are otherwise unresolved due to peak broadening from extensive sodium adduction. Although sulfolane is more effective than m-NBA at protein ion desalting, m-NBA reduces salt clusters at high m/z and can increase the signal-to-noise ratios of protein ions by reducing chemical noise. Desalting is likely a result of these supercharging reagents binding sodium ions in solution, thereby reducing the sodium available to adduct to protein ions. PMID:25133273

Cassou, Catherine A; Williams, Evan R

2014-10-01

395

Silver nanoparticles incorporated onto ordered mesoporous silica from Tollen's reagent  

NASA Astrophysics Data System (ADS)

Noble metal nanostructures supported on mesoporous silica are bridge between traditional silica adsorbents and modern catalysts. In this work the Ag/SBA-15 mesoporous materials were synthesized and characterized. Various forms of nanosilver supported on ordered mesoporous template have been successfully obtained via proposed procedures. In all synthesized materials, Tollen's reagent (diammine silver complex [Ag(NH3)2]+) was used as a silver source. Silver nanoparticles were prepared by reduction of ammoniacal silver complex by formaldehyde in the solution of stabilizer. After reduction, Ag nanoparticles could be deposited on SBA-15, or added during traditional synthesis of SBA-15 giving silver or silver chloride nanoparticles in the combination with porous silica. Silver nanostructures as nanoparticles or nanowires were also embedded onto the SBA-15 by incipient wetness impregnation of silver ions. Absorbed silver ions were next reduced under hydrogen at high temperature. There are many advantages of utilized ammoniacal silver complex as a silver source. Proposed method is capable to synthesis of various metal nanostructures with controlled composition and morphology. The silver ammonia complex is composed of two ions surrounding and protecting the central silver ion, so it is possible to obtain very small nanoparticles using simple approach without any functionalization of external and internal surface of SBA-15. This approach allows obtaining greatly small silver nanoparticles on SBA-15 (4 nm) or nanowires depending on the metal loading amount. Moreover, the colloidal silver solution prepared from Tollen's reagent, in the presence of triblock copolymer, remains stable for a long time. Reduction of Tollen's reagent to silver colloidal solution seems to be efficient, fast and interesting approach for the preparation of supported silver nanostructures Obtained samples were characterized by powder X-ray diffraction, small angle X-ray scattering (SAXS), UV-vis spectroscopy, transmission electron microscopy (TEM), nitrogen adsorption-desorption isotherms and photoacoustic spectroscopy (PAS).

Zienkiewicz-Strza?ka, M.; Pasieczna-Patkowska, S.; Kozak, M.; Pikus, S.

2013-02-01

396

A review of reagents for fluorescence microscopy of cellular compartments and structures, Part III: reagents for actin, tubulin, cellular membranes, and whole cell and cytoplasm.  

PubMed

Non-antibody commercial fluorescent reagents for imaging of cytoskeletal structures have been limited primarily to tubulin and actin, with the main factor in choice based mainly on whether cells are live or fixed and permeabilized. A wider range of options exist for cell membrane dyes, and the choice of reagent primarily depends on the preferred localization in the cell (i.e., all membranes or only the plasma membrane) and usage (i.e., whether the protocol involves fixation and permeabilization). For whole-cell or cytoplasmic imaging, the choice of reagent is determined mostly by the length of time that the cells need to be visualized (hours or days) and by fixation status. Presented here is a discussion on choosing commercially available reagents for these cellular structures, with an emphasis on use for microscopic imaging, with a featured reagent for each structure, a recommended protocol, troubleshooting guide, and example image. PMID:24510770

Kilgore, Jason A; Dolman, Nick J; Davidson, Michael W

2014-01-01

397

The amazing shift.  

PubMed

Some learn by hearing. Some learn by seeing. We all learn by doing. In an effort to creatively integrate skills evaluation and critical thinking in our new nurses, we developed an educational offering entitled "The Amazing Shift." In this activity, small teams of graduate nurses in our medical-surgical residency are tasked with managing simulated patient scenarios within specific time constraints, similar to managing a multipatient assignment on their unit. This "low-tech" approach has consistently been selected as one of the most meaningful classroom-based activities by the participants. PMID:25237923

Elledge, Carole M

2014-01-01

398

STEM Colorado: Doppler Shift  

NSDL National Science Digital Library

This applet demonstrates the Doppler shift. The user can control the frequency of the sound source and the sound speed. The chart recorder at the bottom displays the wave crests as detected by the receiver and their frequency. It also displays the instantaneous wavelength if the ear is at rest. The user can drag the source or the receiver to any location in the display and choose the velocity of each. This is part of a larger collection of applets by STEM Colorado focused mostly on topics in astronomy.

Mccray, Richard; Koelemay, Andrew

2008-08-30

399

Structural and catalytic properties of lanthanide (La, Eu, Gd) doped ceria  

SciTech Connect

Ce{sub 0.9}M{sub 0.1}O{sub 2-{delta}} mixed oxides (M=La, Eu and Gd) were synthesized by coprecipitation. Independent of the dopant cation, the obtained solids maintain the F-type crystalline structure, characteristic of CeO{sub 2} (fluorite structure) without phase segregation. The ceria lattice expands depending on the ionic radii of the dopant cation, as indicated by X-ray diffraction studies. This effect also agrees with the observed shift of the F{sub 2g} Raman vibrational mode. The presence of the dopant cations in the ceria lattice increases the concentration of structural oxygen vacancies and the reducibility of the redox pair Ce{sup 4+}/Ce{sup 3+}. All synthesized materials show higher catalytic activity for the CO oxidation reaction than that of bare CeO{sub 2}, being Eu-doped solid the one with the best catalytic performances despite of its lower surface area. - Graphical abstract: In this work, Ce{sub 0.9}M{sub 0.1}O{sub 2-{delta}} mixed oxides (M=La, Eu and Gd) were synthesized by coprecipitation. Independent of the dopant cation, the obtained solids maintain the F-type crystalline structure, characteristic of CeO{sub 2} (fluorite structure) without phase segregation. The ceria lattice expands depending on the ionic radii of the dopant cation, as indicated by X-ray diffraction studies. This effect also agrees with the observed shift of the F{sub 2g} Raman vibrational mode. The presence of the dopant cations in the ceria lattice increases the concentration of structural oxygen vacancies and the reducibility of the redox pair Ce{sup 4+}/Ce{sup 3+}. All synthesized materials show higher catalytic activity for the CO oxidation reaction than that of bare CeO{sub 2}, being Eu-doped solid the one with the best catalytic performances despite of its lower surface area. Highlights: > Lanthanide doped ceria as catalytic supports for CO oxidation reaction. > A higher concentration of oxygen vacancies promotes a higher catalytic activity. > Eu-doped ceria shows improved catalytic properties for the CO oxidation reaction.

Hernandez, W.Y., E-mail: yesidhdz@hotmail.com [Instituto de Ciencia de Materiales de Sevilla, Centro Mixto Universidad de Sevilla-CSIC, Avda. Americo Vespucio 49, 41092 Seville (Spain); Laguna, O.H.; Centeno, M.A.; Odriozola, J.A. [Instituto de Ciencia de Materiales de Sevilla, Centro Mixto Universidad de Sevilla-CSIC, Avda. Americo Vespucio 49, 41092 Seville (Spain)

2011-11-15

400

Radiation resistance of biological reagents for in situ life detection.  

PubMed

Life on Mars, if it exists, may share a common ancestry with life on Earth derived from meteoritic transfer of microbes between the planets. One means to test this hypothesis is to isolate, detect, and sequence nucleic acids in situ on Mars, then search for similarities to known common features of life on Earth. Such an instrument would require biological and chemical components, such as polymerase and fluorescent dye molecules. We show that reagents necessary for detection and sequencing of DNA survive several analogues of the radiation expected during a 2-year mission to Mars, including proton (H-1), heavy ion (Fe-56, O-18), and neutron bombardment. Some reagents have reduced performance or fail at higher doses. Overall, our findings suggest it is feasible to utilize space instruments with biological components, particularly for mission durations of up to several years in environments without large accumulations of charged particles, such as the surface of Mars, and have implications for the meteoritic transfer of microbes between planets. PMID:23330963

Carr, Christopher E; Rowedder, Holli; Vafadari, Cyrus; Lui, Clarissa S; Cascio, Ethan; Zuber, Maria T; Ruvkun, Gary

2013-01-01

401

Adapter reagents for protein site specific dye labeling.  

PubMed

Chemoselective protein labeling remains a significant challenge in chemical biology. Although many selective labeling chemistries have been reported, the practicalities of matching the reaction with appropriately functionalized proteins and labeling reagents is often a challenge. For example, we encountered the challenge of site specifically labeling the cellular form of the murine Prion protein with a fluorescent dye. To facilitate this labeling, a protein was expressed with site specific p-acetylphenylalanine. However, the utility of this acetophenone reactive group is hampered by the severe lack of commercially available aminooxy fluorophores. Here we outline a general strategy for the efficient solid phase synthesis of adapter reagents capable of converting maleimido-labels into aminooxy or azide functional groups that can be further tuned for desired length or solubility properties. The utility of the adapter strategy is demonstrated in the context of fluorescent labeling of the murine Prion protein through an adapted aminooxy-Alexa dye. © 2014 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 102: 273-279, 2014. PMID:24599728

Thompson, Darren A; Evans, Eric G B; Kasza, Tomas; Millhauser, Glenn L; Dawson, Philip E

2014-05-01

402

The Effect of Reagents Mimicking Oxidative Stress on Fibrinogen Function  

PubMed Central

Fibrinogen is one of the plasma proteins most susceptible to oxidative modification. It has been suggested that modification of fibrinogen may cause thrombotic/bleeding complications associated with many pathophysiological states of organism. We exposed fibrinogen molecules to three different modification reagents—malondialdehyde, sodium hypochlorite, and peroxynitrite—that are presented to various degrees in different stages of oxidative stress. We studied the changes in fibrin network formation and platelet interactions with modified fibrinogens under flow conditions. The fastest modification of fibrinogen was caused by hypochlorite. Fibers from fibrinogen modified with either reagent were thinner in comparison with control fibers. We found that platelet dynamic adhesion was significantly lower on fibrinogen modified with malondialdehyde and significantly higher on fibrinogen modified either with hypochlorite or peroxynitrite reflecting different prothrombotic/antithrombotic properties of oxidatively modified fibrinogens. It seems that, in the complex reactions ongoing in living organisms at conditions of oxidation stress, hypochlorite modifies proteins (e.g., fibrinogen) faster and more preferentially than malondialdehyde. It suggests that the prothrombotic effects of prior fibrinogen modifications may outweigh the antithrombotic effect of malondialdehyde-modified fibrinogen in real living systems. PMID:24235886

Stikarova, Jana; Kotlin, Roman; Riedel, Tomas; Suttnar, Jiri; Pimkova, Kristyna; Chrastinova, Leona; Dyr, Jan E.

2013-01-01

403

Interaction of pantetheinase with sulfhydryl reagents and disulfides.  

PubMed

The effect of many thiol reagents and disulfides on pantetheinase (E.C. 3.5.1.-; pantetheine hydrolase) was studied in the presence or absence of S-pantetheine-3-pyruvate as substrate. Iodoacetamide, iodoacetate, bromopyruvate and N-ethylmaleimide irreversibly inactivate the enzyme at very different rates. Inactivation constants, corrected for the different reactivity of halogeno derivatives with non-protein thiols, suggest the presence of an essential sulfhydryl group in the enzyme and a negatively charged environment near this group. p-Chloromercuribenzoate is the most effective inhibitor; 2-nitro-5-thiocyanobenzoate, o-iodosobenzoate and hydrogen peroxide give a biphasic inhibition pattern, indicating the existence of two sulfhydryl groups whose modification affects activity. Organic arsenicals decrease activity to about 50%. Neutral and positively charged disulfides are effective inhibitors. Substrate protects the enzyme from inactivation, except in the case of negatively charged disulfides, where the presence of substrate enhances the inhibitory effect. Titration with Ellman's reagent or 4,4'-dithiodipyridine under various experimental conditions demonstrated the existence of two sulfhydryls and three disulfides in the fully active enzyme. Pantetheinase may become inactive during purification with concomitant loss of one titrable sulfhydryl group. PMID:3753883

Ricci, G; Nardini, M; Chiaraluce, R; Duprè, S; Cavallini, D

1986-03-01

404

Enhancement of immunotoxin activity using chemical and biological reagents.  

PubMed Central

One of the major discoveries of effective therapeutics is the use of targeted treatment, such as antibody-directed toxins, i.e. immunotoxins; however, this medicine delivery strategy is still at a developmental stage. A number of problems need to be resolved; one is their inefficacy when applied in vivo. Research has stimulated interest in this area through the use of chemical reagents and other moieties to increase the activity of immunotoxins. In this article, reagents that can potentiate the cytotoxicity of immunotoxins are reviewed and the mechanisms that increase activity of immunotoxins are discussed. Lysosomotropic amines, especially ammonium chloride and chloroquine, may raise the pH value of the lysosome in which the conjugates enter. Carboxylic ionophores, e.g. monensin, can influence Golgi vacuolation, which may facilitate the routing of conjugates, augmenting activity. Calcium channel antagonists may increase immunotoxin killing through morphological or other mechanisms that are not yet well understood. Viral particles and surface structure can enhance the cytotoxicity of conjugates, probably through the mechanism of disrupting endosomes. In addition, cytokines, beta-adrenergic blockers, immunosuppressive agents (cyclosporin A) and some antibiotics (daunorubicin) can be used to increase the effect of immunotoxins. PMID:9155057

Wu, M.

1997-01-01

405

Studies of electronic configurations in the emission spectra of lanthanides and actinides: application to the interpretation of Es I and Es II, predictions for Fm I  

SciTech Connect

The interpretation of the spectra of free atoms and gaseous ions in the 4f{sup N} and 5f{sup N} periods became less active after critical compilations of energy levels appeared. However, several spectra are still under study and the application of the Racah-Slater and HFR methods to extended sets of configurations leads to revisions and additions. In doubly charged ions of lanthanides, the treatment of configuration interaction by means of effective parameters and by extension of the basis of states are both important. Concerning actinides, calculations of several observables (Lande factors and isotope shifts in Pu I, hyperfine constants, transition probabilities) prove the quality of eigenfunctions. The classification of Es I and Es II has been extended and radial parameters for fine and hyperfine structures have been derived. Level predictions for the next element fermium are supported by parameter extrapolations.

Wyart, Jean-Francois [Laboratoire Aime Cotton, CNRS, Batiment 505, Centre Universitaire, FR-91405 Orsay Cedex (France)]. E-mail: jean-francois.wyart@lac.u-psud.fr; Blaise, Jean [Laboratoire Aime Cotton, CNRS, Batiment 505, Centre Universitaire, FR-91405 Orsay Cedex (France); Worden, Earl F. [Physics and Advanced Technologies Directorate, Lawrence Livermore National Laboratory, L-044, Livermore, CA 94550 (United States)

2005-02-15

406

Measurements of Atomic Oscillator Strengths of Selected Lanthanides  

NASA Astrophysics Data System (ADS)

Atomic oscillator strengths are important quantities that find uses in many areas of physics such as the determination of stellar abundances, the search for new laser materials, plasma physics, and laser isotope separation. In particular, there is a need for accurate atomic oscillator strength data for the lanthanide and actinide elements. Unfortunately, many of the methods for measuring oscillator strengths depend on parameters such as the density of atoms, line profiles, laser power and other parameters which are often uncertain. This work has focused on the measurement of atomic oscillator strengths of lanthanide and actinide atoms using both conventional and nonconventional laser techniques. In this work, a simple, accurate method employing laser photoionization spectroscopy has been developed for measuring excited state branching ratios and oscillator strengths. This method is particularly attractive since it is independent of atomic density, laser power and Doppler broadening. Two pulsed dye lasers are used to populate the upper and lower levels of the transition of interest. A third pulsed dye laser then probes the time evolution of the lower level by a two step photoionization process. The time evolution of the lower level, coupled with the lifetimes of the upper and lower levels allows the branching ratio and transition oscillator strength to be determined. This technique has been used to measure atomic oscillator strengths and excited state branching ratios of neutral cerium, gadolinium and ytterbium. This method has also been extended to a transmission technique where birefringence is probed as opposed to populations. In addition, emission intensity data obtained from the Kitt Peak 1m Fourier transform spectrometer has been used to determine branching ratios of neutral cerium. These branching ratios were coupled with independent lifetime measurements to obtain transition probabilities. From these measurements, the temperature of the source could be determined. Absolute transition probabilities for any transition could then be determined from the intensity and upper level energy of the transition. The advantage of using Fourier transform spectroscopy techniques to determine branching ratios is that large numbers of oscillator strengths may be rapidly determined.

Bisson, Scott Edward

407

Anion and solvent induced chirality inversion in macrocyclic lanthanide complexes.  

PubMed

A series of the lanthanide(III) or yttrium(III) complexes of the type [LnL(NO3)(H2O)2](NO3)2, [LnL(NO3)(H2O)](NO3)2, [LnL(H2O)2](NO3)3, and [LnLCl(H2O)2]Cl2 where L is an all-R or all-S enantiomer (L(R) or L(S)) of the chiral hexaaza macrocycle, 2(R),7(R),18(R),23(R)- or 2(S),7(S),18(S),23(S)-1,8,15,17,24,31-hexaazatricyclo[25.3.1.1.0.0]-dotriaconta-10,12,14,26,28,30-hexaene, and Ln(III) = Sm(III), Tb(III), Ho(III), Er(III), Tm(III), Yb(III), Lu(III), or Y(III), have been synthesized and structurally characterized. The crystal structure of the free macrocycle shows a highly twisted molecule, preorganized for the formation of helical complexes. The crystal structures of the lanthanide(III) complexes show two different diastereomeric forms of the macrocycle with different configurations at the stereogenic amine nitrogen atoms: (RRRR) or (RSRS) (denoted as L(RI) and L(RII), respectively). The L(RI) diastereomeric form of the nitrate derivatives [LnL(NO3)(H2O)](NO3)2 (Ln = Ho, Er) and [LnL(H2O)2](NO3)3 (Ln = Tm, Yb, Lu) convert slowly to the L(RII) form in methanol or acetonitrile solutions, while this process is not observed for the L(RI) diastereomers of analogous chloride derivatives [LnL(H2O)2]Cl3 (Ln = Tm, Yb, Lu). On the other hand, the L(RI) ? L(RII) conversion for these Tm(III), Yb(III), and Lu(III) chloride derivatives can be triggered by the addition of external nitrate anions. The circular dichroism (CD) and (1)H NMR data indicate initial fast exchange of axial chloride for axial nitrate ligand, followed by slow chirality inversion of the equatorial macrocyclic ligand. PMID:24147755

Gerus, Aleksandra; Slepokura, Katarzyna; Lisowski, Jerzy

2013-11-01

408

Transitioning to 12-hour shifts  

Microsoft Academic Search

In 1989, Yankee Rowe nuclear power station successfully implemented a 12-hour shift schedule for all shiftworkers (control room personnel, auxiliary operators, and radiation protection shift technicians) with many positive effects on morale, motivation, and performance. The transition from an 8-hour to a 12-hour shift schedule was initiated, organized, and promoted by the shiftworkers themselves after they had identified numerous inadequacies

P. S. Suter; S. M. Cervassi

1993-01-01

409

Two 3D Porous Lanthanide-Fumarate-Oxalate Frameworks Exhibiting Framework Dynamics and Luminescent Change upon Reversible De-  

E-print Network

Two 3D Porous Lanthanide-Fumarate-Oxalate Frameworks Exhibiting Framework Dynamics and Luminescent September 26, 2006 We present two porous luminescent compounds, [Ln2(fumarate)2(oxalate)(H2O)4],4H2O (Ln of oxalate pillared lanthanide- fumarate layers with intersected channels occupied by guest water

Gao, Song

410

The Partitioning of Americium and the Lanthanides Using Tetrabutyldiglycolamide (TBDGA) in Octanol and in Ionic Liquid Solution  

SciTech Connect

Separations among the lanthanides and the separation of Am from the lanthanides remain challenging, and research in this area continues to expand. The separation of adjacent lanthanides is of interest to high-tech industries because individual lanthanides have specialized uses and are in short supply. In nuclear fuel cycle applications Am would be incorporated into fast reactor fuels, yet the lanthanides are not desired. In this work the diamide N,N,N',N'-tetrabutyldiglycolamide (TBDGA) was investigated as a ligand for lanthanide and Am solvent extraction in both molecular and room temperature ionic liquid (RTIL) diluents. The RTIL [C4MIM][Tf2N-] showed very high extraction efficiency for these trivalent metals from low nitric acid concentrations, while the molecular diluent 1-octanol showed high extraction efficiency at high acid concentrations. This was attributed to the extraction of ionic nitrate complexes by the RTIL, whereas 1-octanol extracted neutral nitrate complexes. TBDGA in RTIL did not provide adequate separation factors for Am/lanthanide partitioning, but 1-octanol did show reasonable separation possibilities. Lanthanide intergroup separations appeared to be feasible in both diluents, but with higher separation factors from 1-octanol.

M.E. Mincher; D.L. Quach; Y.J. Liao; B.J. Mincher; C.M. Wai

2012-11-01

411

Oxoclusters of the Lanthanides Begin to Resemble Solid-State Materials at Very Small Cluster Sizes: Structure  

E-print Network

Oxoclusters of the Lanthanides Begin to Resemble Solid-State Materials at Very Small Cluster Sizes of Nd3, with pairs of tetrahedral oxo ligands separating the Nd3 planes and Se, SeSe, SePh, pyridine lanthanide ions is a fundamentally important process with a continuously expanding range of applications

Lawson, Catherine L.

412

4858 J. Am. Chem. SOC.1994, 116, 4858-4865 Lanthanide-Cyclodextrin Complexes as Probes for Elucidating  

E-print Network

4858 J. Am. Chem. SOC.1994, 116, 4858-4865 Lanthanide-Cyclodextrin Complexes as Probes of cyclodextrin-substrate inclusion complexes. Lanthanide-induced shiftsarereported for complexes of aspartame for the separation of enantiomers.l.5 Alternatively,the complexes formed between a pair of enantiomers

Bogyo, Matthew

413

A Bridge to Coordination Isomer Selection in Lanthanide(III) DOTA-tetraamide Complexes  

PubMed Central

Interest in macrocyclic lanthanide complexes such as DOTA is driven largely through interest in their use as contrast agents for MRI. The lanthanide tetraamide derivatives of DOTA have shown considerable promise as PARACEST agents, taking advantage of the slow water exchange kinetics of this class of complex. We postulated that water exchange in these tetraamide complexes could be slowed even further by introducing a group to sterically encumber the space above the water coordination site, thereby hindering the departure and approach of water molecules to the complex. The ligand 8O2-bridged-DOTAM was synthesized in a 34% yield from cyclen. It was found that the lanthanide complexes of this ligand did not possess a water molecule in the inner coordination sphere of the bound lanthanide. The crystal structure of the ytterbium complex revealed that distortions to the coordination sphere were induced by the steric constraints imposed on the complex by the bridging unit. The extent of the distortion was found to increase with increasing ionic radius of the lanthanide ion, eventually resulting in a complete loss of symmetry in the complex. Because this ligand system is bicyclic, the conformation of each ring in the system is constrained by that of the other, in consequence inclusion of the bridging unit in the complexes means only a twisted square antiprismatic coordination geometry is observed for complexes of 8O2-bridged-DOTAM. PMID:17295475

Vipond, Jeff; Woods, Mark; Zhao, Piyu; Tircso, Gyula; Ren, Jimin; Bott, Simon G.; Ogrin, Doug; Kiefer, Garry E.; Kovacs, Zoltan; Sherry, A.Dean

2008-01-01

414

Microbial formation of lanthanide-substituted magnetites by Thermoanaerobacter sp. TOR-39  

SciTech Connect

Lanthanide (Nd, Gd, Tb, Ho, and Er)-substituted magnetites, LyFe3-yO4 (L, lanthanide) were microbially synthesized using L-mixed precursors, LxFe1-xOOH, where x was between 0.01 and 0.2. By combining lanthanides (normally considered toxic to microorganisms) into the akaganeite precursor phase, we were able to mitigate some of the toxicity enabling the microorganisms to produce L-substituted magnetites. A metal reducing bacterium, Thermoanaerobacter ethanolicus successfully converted the mixed akaganeite to L-substituted magnetite while avoiding the potentially toxic effects of soluble L-ions. At higher mixing levels (0.02 < x <0.05) the poor crystallinity of L-mixed precursors increased the concentration of soluble toxic L-ions in the media. Nevertheless, using L-mixed precursors enabled production of microbially synthesized L-substituted magnetite with considerably higher L-concentration than could be obtained when the lanthanides were added as soluble salts. This method can therefore be used to extend the application for nanofermentation to fields where there is a need for nanoscale materials that involve elements such as lanthanides that are toxic or inhibitory to bacterial growth.

Moon, Ji Won [ORNL; Roh, Yul [Chonnam National University, Gwangju; Yeary, Lucas W [ORNL; Lauf, Robert J [ORNL; Rawn, Claudia J [ORNL; Love, Lonnie J [ORNL; Phelps, Tommy Joe [ORNL

2007-01-01

415

Coordination chemistry of several radius-sensitive complexones and applications to lanthanide-actinide separations  

SciTech Connect

The relationships between the lanthanide complex formation equilibria and the lanthanide-actinide separation application of three radius sensitive ligands have been studied. The consecutive stepwise formation constants of the 1:1, 2:1, and 3:1 chelate species formed by the interaction of DHDMB and the tripositive lanthanides and yttrium were determined potentiometrically at 0.1 M ionic strength and 25/sup 0/C. Results indicate that three different coordination modes, one tridentate and two bidentate are in evidence. Tracer level /sup 241/Am - /sup 155/Eu cation-exchange experiments utilizing DHDMB eluents indicate that this dihydroxycarboxylate does not form a sufficiently strong americium complex to elute that actinide ahead of europium. The overall stability of the americium 3:1 complex appears intermediate between samarium and europium. Cation-exchange elutions of /sup 241/Am, /sup 155/Eu, and /sup 160/Tb mixtures with EEDTA solutions prove that the EEDTA ligand is capable of eluting americium ahead of all of the tripositive lanthanide cations. The minimum separation occurs with terbium, where the Am-Tb separation factor is 1.71. 1,5-diaminopentane-N,N,N',N'-tetraacetic acid (PMDTA) was synthesized using cation exchange. A mathematical method was developed for the formation constants of the protonated and unprotonated lanthanide-PMDTA complexes from potentiometry. Cation-exchange elutions of tracer quantities of Am, Eu, and Tb revealed that terbium is eluted ahead of both americium and europium.

Potter, M.W.

1981-10-01

416

New crystal structural families of lanthanide chloride alcohol/water complexes  

SciTech Connect

The exploration of lanthanide chloride compounds as possible scintillation materials for gamma ray and neutron detection has led to the discovery of several new families of crystal structures with the general formula LnCl3(CH3OH)x(H2O)y. The specific crystal structure depends on the water/methanol content and lanthanide ion. The coordination of the light (large) lanthanides is the typical value of 8 and reduces to 7 for the heavier (small) lanthanides. The binding energy of water versus alcohol ligands is comparable, so that if water is present in the system, it is typically incorporated as a ligand in the crystal. In these crystals, the molecular adducts occur as monomers, dimers, and dichloro-bridged chains. These, in turn, form 3-D frameworks through H-bonds to the Cl atoms. Other distinct crystal structures are predicted, given the volume changes due to the lanthanide contraction, the water content of the crystal growth solutions, and the specific halide.

Chakoumakos, Bryan C [ORNL; Custelcean, Radu [ORNL; Ramey, Joanne Oxendine [ORNL; Boatner, Lynn A [ORNL

2012-01-01

417

Microfluidic screening of electrophoretic mobility shifts elucidates riboswitch binding function.  

PubMed

Riboswitches are RNA sensors that change conformation upon binding small molecule metabolites, in turn modulating gene expression. Our understanding of riboswitch regulatory function would be accelerated by a high-throughput, quantitative screening tool capable of measuring riboswitch-ligand binding. We introduce a microfluidic mobility shift assay that enables precise and rapid quantitation of ligand binding and subsequent riboswitch conformational change. In 0.3% of the time required for benchtop assays (3.2 versus 1020 min), we screen and validate five candidate SAM-I riboswitches isolated from thermophilic and cryophilic bacteria. The format offers enhanced resolution of conformational change compared to slab gel formats, quantitation, and repeatability for statistical assessment of small mobility shifts, low reagent consumption, and riboswitch characterization without modification of the aptamer structure. Appreciable analytical sensitivity coupled with high-resolution separation performance allows quantitation of equilibrium dissociation constants (K(d)) for both rapidly and slowly interconverting riboswitch-ligand pairs as validated through experiments and modeling. Conformational change, triplicate mobility shift measurements, and K(d) are reported for both a known and a candidate SAM-I riboswitch with comparison to in-line probing assay results. The microfluidic mobility shift assay establishes a scalable format for the study of riboswitch-ligand binding that will advance the discovery and selection of novel riboswitches and the development of antibiotics to target bacterial riboswitches. PMID:23343213

Karns, Kelly; Vogan, Jacob M; Qin, Qian; Hickey, Scott F; Wilson, Stephen C; Hammond, Ming C; Herr, Amy E

2013-02-27

418

Phase shifting diffraction interferometer  

DOEpatents

An interferometer which has the capability of measuring optical elements and systems with an accuracy of {lambda}/1000 where {lambda} is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about {lambda}/50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms. 8 figs.

Sommargren, G.E.

1996-08-29

419

Phase shifting diffraction interferometer  

DOEpatents

An interferometer which has the capability of measuring optical elements and systems with an accuracy of .lambda./1000 where .lambda. is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about .lambda./50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms.

Sommargren, Gary E. (Santa Cruz, CA)

1996-01-01

420

Phase shifting interferometer  

DOEpatents

An interferometer which has the capability of measuring optical elements and systems with an accuracy of .lambda./1000 where .lambda. is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about .lambda./50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. Whereas current interferometers illuminate the optic to be tested with an aberrated wavefront which also limits the accuracy of the measurement, this interferometer uses an essentially perfect spherical measurement wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms.

Sommargren, Gary E. (Santa Cruz, CA)

1999-01-01

421

A spectrophotometric method for determination of chemical oxygen demand using home-made reagents  

Microsoft Academic Search

A novel spectrophotometric assay method using home-made reagents that can be used to determine the chemical oxygen demand (COD) in real wastewater is described. The home-made reagents were used instead of the American Hach reagents. The principle of measurement was based on direct determination of the concentration change that Cr6+ is reduced intensely to Cr3+ resulting from potassium dichromate oxidation

Jun Li; Tao Tao; Xue-bin Li; Jiao-lan Zuo; Tong Li; Jin Lu; Shu-hui Li; Li-zhen Chen; Chun-yang Xia; Yong Liu; Yan-li Wang

2009-01-01

422

Hydrazine reagents as derivatizing agents in environmental analysis – a critical review  

Microsoft Academic Search

Hydrazine reagents are a well-known group of derivatizing agents for the determination of aldehydes and ketones in liquid\\u000a and gaseous samples. Within this article, the most important hydrazine reagents are critically summarized, and their major\\u000a applications in different fields, including environmental analysis, food chemistry and industrial analysis are introduced.\\u000a As 2,4-dinitrophenylhydrazine (DNPH) is the basic reagent for several international standard

Martin Vogel; Andrea Büldt; Uwe Karst

2000-01-01

423

Blood-typing of Indian Water Buffaloes with Reagents for Antigenic Factors of Cattle  

Microsoft Academic Search

MORE than eighty heritable antigenic factors have been detected on the erythrocytes (cells) of cattle by their reactions with blood-grouping reagents; the reagent being an antibody population made relatively specific for a particular factor by appropriate absorptions1. Using cattle reagents, it has been shown that at least nine genetic blood-group systems of cattle have their homologues in American bison, Bison

S. P. Datta; W. H. Stone

1963-01-01

424

UP-TORR: Online Tool for Accurate and Up-to-Date Annotation of RNAi Reagents  

PubMed Central

RNA interference (RNAi) is a widely adopted tool for loss-of-function studies but RNAi results only have biological relevance if the reagents are appropriately mapped to genes. Several groups have designed and generated RNAi reagent libraries for studies in cells or in vivo for Drosophila and other species. At first glance, matching RNAi reagents to genes appears to be a simple problem, as each reagent is typically designed to target a single gene. In practice, however, the reagent–gene relationship is complex. Although the sequences of oligonucleotides used to generate most types of RNAi reagents are static, the reference genome and gene annotations are regularly updated. Thus, at the time a researcher chooses an RNAi reagent or analyzes RNAi data, the most current interpretation of the RNAi reagent–gene relationship, as well as related information regarding specificity (e.g., predicted off-target effects), can be different from the original interpretation. Here, we describe a set of strategies and an accompanying online tool, UP-TORR (for Updated Targets of RNAi Reagents; www.flyrnai.org/up-torr), useful for accurate and up-to-date annotation of cell-based and in vivo RNAi reagents. Importantly, UP-TORR automatically synchronizes with gene annotations daily, retrieving the most current information available, and for Drosophila, also synchronizes with the major reagent collections. Thus, UP-TORR allows users to choose the most appropriate RNAi reagents at the onset of a study, as well as to perform the most appropriate analyses of results of RNAi-based studies. PMID:23792952

Hu, Yanhui; Roesel, Charles; Flockhart, Ian; Perkins, Lizabeth; Perrimon, Norbert; Mohr, Stephanie E.

2013-01-01

425

Current and potential therapeutic uses of lanthanide radioisotopes.  

PubMed

In the last 25 years, diagnostic nuclear medicine has come to depend on the versatile chemistry of a single radioisotope, technetium-99m (Tc-99m). Different chelating molecules can be used to guide Tc-99m through various physiological pathways in the body to gain information about disease states. No single radioisotope similarly dominates therapeutic applications. In the field of radioisotope therapy, much discussion and debate have focused on what radioisotope might be "ideal" for treatment of malignant tumors. The ideal may not be a single radioisotope, but rather the class of very closely related radiolanthanides and lanthanide-like radioisotopes. These radioisotopes possess strikingly similar chemistries and thus all may be conjugated to biomolecules using a single chelate, the DOTA moiety (and its chemical analogs). They also provide a wide range of physical characteristics, such as half-lives and beta energies, that can be chosen to match the biological properties of the conjugated biomolecule and the malignant tumor. Thus, the radiolanthanide-DOTA bioconjugate model provides a set of physically diverse, but chemically very similar, therapeutic radiopharmaceutical agents, the individual members of which can be tailored to treat specific types of cancers. PMID:11190486

Cutler, C S; Smith, C J; Ehrhardt, G J; Tyler, T T; Jurisson, S S; Deutsch, E

2000-12-01

426

Triplet energy harvesting by lanthanides in conjugated polymers  

NASA Astrophysics Data System (ADS)

We report the design, synthesis, and spectroscopic characterization of polyphenylene-type polymers that can be used to sensitize europium complexes. Although benzophenone is widely studied and characterized, polybenzophenones have not been widely used in photophysical studies. The properties of poly(4'-methyl-2,4-benzophenone) (MB), poly(4'-methyl-2,5-benzophenone) (PB) and poly[2,2'-bipyridine-5,5'-diyl(2,5-didecoxy-1,4-phenylene)] (PBP) are described in this paper. All three polymers have backbones that are similar to polyphenylene. PBP has a bipyridine unit that alternates with a phenyl ring. Benzophenone rings are polymerized with para or meta linkages in PB and MB, respectively. All three polymers have similar emission maxima at 430 nm, but PBP has a higher quantum efficiency of emission. The polymers studied in this paper proved to be of lower energy than what is needed to sensitize many europium complexes. In almost all of the lanthanide complexes the ligands played a major role in the emission properties. This was elaborated in studies done previously. Europium chelates of the two different ligands: di(2-thienoyl)methane (DTM) and di(2-naphthoyl)methane (DNM) proved to be of comparable energies with the polymers studied. Results showed that energy transfer did occur between the polymers and the europium chelates, but the energy transfer was not 100% because residual emission from the polymers was detected.

Padmaperuma, Asanga B.; Case, Patrick J.; Harper, Aaron W.

2002-11-01

427

Preparation of lanthanide nitrides by carbothermic reduction using ammonia  

NASA Astrophysics Data System (ADS)

Some lanthanide dicarbides (CeC 2, PrC 2 and NdC 2) were prepared by the carbothermic reduction of their oxides (Ce0 2, Pr 6O 11, and Nd 2O 3) with carbon in vacuum at 1400°C. These carbides were converted into mononitrides (CeN, PrN and NdN) at 900°C under the gas flow of NH 3 or a mixture of gases (H 2:N 2 = 3:1). The nitrogen activity exhibited by NH 3 flow was calculated to be more than 1.0 × 10 3 and that of the mixture gas was 0.5. Since only mononitrides were obtained even when NH 3 with enormously high nitrogen activity was used, the higher nitride (e.g., sesquinitride or dinitride) seems not to exist in the Ce?N, Pr?N, Nd?N systems. The formation of CH 4 by the reaction of free carbon with the gas is found to depend on the hydrogen activity and carbon activity.

Nakagawa, Takashi; Matsuoka, Hirotaka; Sawa, Masaji; Idehara, Kenji; Katsura, Masahiro

1997-08-01

428

Hydraulically actuated well shifting tool  

SciTech Connect

This patent describes a hydraulically actuated shifting tool for actuating a sliding member in a well tool. It comprises: a housing having a hydraulic fluid bore therein; shifting dog means positioned on the housing for movement away and toward the housing; locking dog means positioned on the housing for movement away and toward the body; shifting dog hydraulic actuating means in fluid communication with the bore for causing engagement of the shifting dogs with the sliding member; locking dog hydraulic actuating means in communication with the bore for causing engagement of the locking dogs with the locking means; and hydraulic shifting means in communication with the bore for causing relative movement between the shifting dog means and the locking dog means for shifting the sliding sleeve.

Roth, B.A.

1992-10-20

429

Environmentally Benign Synthesis of Isoflavone Derivatives Using Polymer-Supported Hypervalent Iodine(III) Reagent  

NASA Astrophysics Data System (ADS)

Isoflavones are synthesized in one-pot manner by action of a hypervalent iodine (III) reagent, ?hydroxy(tosyloxy)iodo?benzene (HTIB, Koser's reagent) on 2'-benzoyloxychalcones in MeOH. A combined usage of iodobenzene diacetate (IBD)—p-toluenesulfonic acid (TsOH) is also effective for the same purpose. As an extension of those monomeric reagents, polymer-supported IBD (PSIBD, poly ?4-(diacetoxy)iodo?styrene) with TsOH works also well with merit of easy separation of isoflavones from the reaction mixture, no liberation of PhI, and reuse of the reagent.

Kawamura, Yasuhiko; Maruyama, Masashi; Yamashita, Kazuyo; Tsukayama, Masao

430

Lanthanide-doped upconversion materials: emerging applications for photovoltaics and photocatalysis.  

PubMed

Photovoltaics and photocatalysis are two significant applications of clean and sustainable solar energy, albeit constrained by their inability to harvest the infrared spectrum of solar radiation. Lanthanide-doped materials are particularly promising in this regard, with tunable absorption in the infrared region and the ability to convert the long-wavelength excitation into shorter-wavelength light output through an upconversion process. In this review, we highlight the emerging applications of lanthanide-doped upconversion materials in the areas of photovoltaics and photocatalysis. We attempt to elucidate the fundamental physical principles that govern the energy conversion by the upconversion materials. In addition, we intend to draw attention to recent technologies in upconversion nanomaterials integrated with photovoltaic and photocatalytic devices. This review also provides a useful guide to materials synthesis and optoelectronic device fabrication based on lanthanide-doped upconversion materials. PMID:25397916

Yang, Weifeng; Li, Xiyan; Chi, Dongzhi; Zhang, Hongjie; Liu, Xiaogang

2014-12-01

431

Coordination of Lanthanide Triflates and Perchlorates with N,N,N',N'-Tetramethylsuccinamide  

SciTech Connect

Compounds formed from the reaction of N,N,N',N'-tetramethylsuccinamide (TMSA) with trivalent lanthanide salts possessing the poorly coordinating counteranions triflate (CF3SO3-) and perchlorate (ClO4-) have been prepared and examined. Structural features of these Ln-TMSA compounds have been studied in the solid phase by thermogravimetric analysis, infrared spectroscopy, and single crystal X-ray diffraction and in solution by infrared spectroscopy. Eight-coordinate compounds derived from coordination of four bidentate, succinamide ligands to the metal ion could be formed with all lanthanides examined. The binding of the succinamide ligand to the lanthanide metal is significantly asymmetric, with differences between the M-O(amide) bond distances for a chelating succinamide of around 0.06? and differences in the M-O-C bond angles of around 28?. Fourier transform-infrared spectroscopy studies in anhydrous acetonitrile suggest that the solid-state structure is maintained in solution.

Rapko, Brian M. (BATTELLE (PACIFIC NW LAB)); McNamara, Bruce K. (BATTELLE (PACIFIC NW LAB)); Rogers, Robin D. (Alabama, Univ Of); Broker, Grant A. (Alabama, Univ Of); Lumetta, Gregg J. (BATTELLE (PACIFIC NW LAB)); Hay, Benjamin P. (BATTELLE (PACIFIC NW LAB))

1999-11-01

432

Effectiveness of a dopant in U-Zr metallic fuel to prevent lanthanide migration  

SciTech Connect

The advanced fast reactor concepts to achieve ultra-high burnup (about 50%) without requiring refueling by way of using metallic alloy fuel have gained interest. Fission product lanthanide accumulation at high burnup is substantial and its migration to cladding and reaction with cladding is a potential life-limiting phenomenon. As a means to solve this problem, adding an element that forms stable compounds with lanthanides to immobilize them has been proposed. The theoretical assessment shows that indium, thallium, gallium, and antimony are good candidates. Except for Sb, because these elements are low-melting temperature elements, liquid metal embrittlement of cladding is a concern if large sized agglomerates exist contacting the cladding. Alloy characterization of as-fabricated samples was performed to examine the effectiveness of the dopant addition method using optical microscopy and scanning electron microscopy. Although preliminary, the present results showed that indium is a better dopant to immobilize lanthanides.

Kim, Yeon Soo; Wieneck, T.; O'Hare, E.; Fortner, J. [Argonne National Laboratory 9700 S. Cass Ave, Argonne, IL 60439 (United States)

2013-07-01

433

Improved separation of Am(III) from the light lanthanides using a soft-donor synergist  

SciTech Connect

The separation of minor actinides from fission products, especially the trivalent lanthanides, remains a difficult problem. Current research has focused on the use of soft-donor groups that have a greater affinity for the trivalent actinides than for the lanthanides. The extractant bis(chlorophenyl)dithio-phosphinic acid was used in combination with a synergist, 4,7-diphenyl- 1,10-phenanthroline, to extract Am(III) and Eu(III) from aqueous nitrate media. The extraction efficiencies of Am(III) and Eu(III) were measured by varying the total ionic strength and concentrations of the extractant, synergist, and nitric acid. Results suggest that this synergistic system may be useful for group separation of the minor actinides from the lanthanides. (authors)

Ensor, Dale D.; Zimmerman, Matthew H. [Chemistry Department, Tennessee Technological University, Cookeville, TN 38505 (United States)

2008-07-01

434

Highly efficient extraction separation of lanthanides using a diglycolamic acid extractant.  

PubMed

Liquid-liquid extraction of lanthanide ions (Ln(3+)) using N,N-dioctyldiglycolamic acid (DODGAA) was comprehensively investigated, together with fluorescence spectroscopic characterization of the resulting extracted complexes in the organic phase. DODGAA enables the quantitative partitioning of all Ln(3+) ions from moderately acidic solutions, while showing selectivity for heavier lanthanides, and provides remarkably high extraction separation performance for Ln(3+) compared with typical carboxylic acid extractants. Furthermore, the mutual separation abilities of DODGAA for light lanthanides are higher than those of organophosphorus extractants. Slope analysis, loading tests, and electrospray ionization mass spectrometry measurements demonstrated that the transfer of Ln(3+) with DODGAA proceeded through a proton-exchange reaction, forming a 1:3 complex, Ln(DODGAA)3. The stripping of Ln(3+) from the extracting phase was successfully achieved under acidic conditions. Time-resolved laser-induced fluorescence spectroscopy revealed that the extracted Eu(3+) ions were completely dehydrated by complexation with DODGAA. PMID:24521914

Shimojo, Kojiro; Aoyagi, Noboru; Saito, Takumi; Okamura, Hiroyuki; Kubota, Fukiko; Goto, Masahiro; Naganawa, Hirochika

2014-01-01

435

Test of Actinide-Lanthanide Separation in an Aluminum-Based Pyrochemical System  

SciTech Connect

The investigation of the actinide and lanthanide distribution between a liquid metal and a molten fluoride salt shows a significant increase of the separation coefficient by using an aluminum-based pyrochemical system instead of a zinc-based system. The obtained values partly depend on the LiF/AlF{sub 3} ratio and can reach more than 30 000 when AlF{sub 3} is in excess with regard to the formation of the cryolite (Li{sub 3} AlF{sub 6}). Furthermore, in the metal phase, the aluminum interacts with the lanthanides to a lesser extent than in other usual metallic solvents. This opens a new way to explore the feasibility of the separation of actinides and lanthanides in the field of nuclear fuel reprocessing.

Rault, Laurence [Institut National Polytechnique de Grenoble (France); Heusch, Murielle [Institut National Polytechnique de Grenoble (France); Allibert, Michel [Institut National Polytechnique de Grenoble (France); Lemort, Florent [Commissariat a l'Energie Atomique (CEA) (France); Deschane, Xavier [Commissariat a l'Energie Atomique (CEA) (France); Boen, Roger [Commissariat a l'Energie Atomique (CEA) (France)

2002-08-15

436

Luminescent Nanoparticles with Lanthanide-Containing Poly(ethylene glycol)-Poly(?-caprolactone) Block Copolymers.  

PubMed

Lanthanide-containing nanoparticles have attracted much attention due to their unique optical properties and potential in nanotechnological applications. An amphiphilic block copolymer of poly(ethylene glycol)-b-poly(?-caprolactone) methyl ether (mPEG-PCL) was functionalized with a dipicolinic acid (dpa) moiety and coordinated to lanthanide ions to afford [Ln(dpa-PCL-PEG-OCH3)3](HNEt3)3 (Ln = Eu(3+), Tb(3+)). Micelle-like nanoparticles of dpa-PCL-PEG-OCH3 macroligand and metal-centered polymers were prepared by solvent displacement methods. Dynamic light scattering analysis (DLS) and cryogenic transmission electron microscopy images confirmed the presence of solid sphere (<47 nm in diameter) and vesicle (>47 nm in diameter) morphologies. The viability and stability of the lanthanide complexes in micelle-like nanoparticles was explored by DLS and luminescence spectroscopy, and found to be stable for several weeks. PMID:25233264

Thévenaz, David C; Monnier, Christophe A; Balog, Sandor; Fiore, Gina L

2014-11-10

437

Membrane-based, dry-reagent prothrombin time tests.  

PubMed

The authors describe a prototype membrane-based, dry-reagent prothrombin time assay for whole blood. This system uses an asymmetric polysulfone membrane to separate plasma from red blood cells, and works with samples as small as 10 microliters. The membrane contains calcium and thromboplastin, and permits the reactions of the complete extrinsic pathway to occur with minimal distortion from membrane surface interactions. Thrombin generation is monitored optically using a rhodamine-110-based fluorescent thrombin substrate. Fluorescence kinetics are analyzed to produce a prothrombin-time--equivalent parameter that can be converted to an international normalized ratio (INR) value. The system provides results that correlate well with conventional liquid phase prothrombin time assays (R2 = 0.96). PMID:8739001

Zweig, S E; Meyer, B G; Sharma, S; Min, C; Krakower, J M; Shohet, S B

1996-01-01

438

Methods for generating phosphorylation site-specific immunological reagents  

DOEpatents

The present invention provides methods for generating phosphorylation site-specific immunological reagents. More specifically, a phosphopeptide mimetic is incorporated into a polypeptide in place of a phosphorylated amino acid. The polypeptide is used as antigen by standard methods to generate either monoclonal or polyclonal antibodies which cross-react with the naturally phosphorylated polypeptide. The phosphopeptide mimetic preferably contains a non-hydrolyzable linkage from the appropriate carbon atom of the amino acid residue to a phosphate group. A preferred linkage is a CF.sub.2 group. Such a linkage is used to generate the phosphoserine mimetic F.sub.2 Pab, which is incorporated into a polypeptide sequence derived from p53 to produce antibodies which recognize a specific phosphorylation state of p53. A CF.sub.2 group linkage is also used to produce the phosphothreonine mimetic F.sub.2 Pmb, and to produce the phosphotyrosine mimetic, F.sub.2 Pmp.

Anderson, Carl W. (Stony Brook, NY); Appella, Ettore (Montgomery, MD); Sakaguchi, Kazuyasu (Montgomery, MD)

2001-01-01

439

Cellulose extraction from orange peel using sulfite digestion reagents.  

PubMed

Orange peel (OP) was used as raw material for cellulose extraction. Two different pulping reagents were used, sodium sulfite and sodium metabisulfite. The effect of the main process parameters, sulfite agent dosage and reaction duration, on cellulose yield was investigated. A central composite rotatable design involving two variables at five levels and response surface methodology were used for the optimization of cellulose recovery. Other two invariable parameters were reaction temperature and hydromodulus. The optimum yields, referred to the weight of double extracted OP, were 40.4% and 45.2% for sodium sulfite and sodium metabisulfite digestions, respectively. The crude celluloses were bleached with hypochlorite and oxygen. The physicochemical characterization data of these cellulose materials indicate good levels of purity, low crystallinities, good whitenesses, good water retention and moderate molecular weights. According to these specific properties the recovered celluloses could be used as fillers, water absorbents, or as raw materials for cellulose derivatives. PMID:21893413

Bicu, Ioan; Mustata, Fanica

2011-11-01

440

Water-soluble organophosphorus reagents for mineralization of heavy metals.  

SciTech Connect

In this report, we have described the principal stages of a two-step process for the in-situ stabilization of actinide ions in the environment. The combination of cation exchange and mineralization appears likely to provide a long-term solution to environments contaminated with heavy metals. Relying on a naturally occurring sequestering agent has obvious potential advantages from a regulatory standpoint. There are additional aspects of this technology requiring further elucidation, including the demonstration of the effect of these treatment protocols on the geohydrology of soil columns, further examination of the influence of humates and other colloidal species on cation uptake, and microbiological studies of phytate hydrolysis. We have learned during the course of this investigation that phytic acid is potentially available in large quantities. In the US alone, phytic acid is produced at an annual rate of several hundred thousand metric tons as a byproduct of fermentation processes (11). This material presently is not isolated for use. Instead, most of the insoluble phyate (as phytin) is being recycled along with the other solid fermentation residues for animal feed. This material is in fact considered undesirable in animal feed. The details of possible separation processes for phytate from these residues would have to be worked out before this untapped resource would be available for application to heavy metal sequestration. The results described emphasize the behavior of actinide and trivalent lanthanide metal ions, as these species are of primary interest to the Department of Energy for the cleanup of the former nuclear weapons production complex. While the specific demonstration includes this limited selection of metal ions, the technique should be readily applicable to any class of metal ions that form insoluble phosphate compounds under appropriate conditions. Further, though this demonstration has been conducted in the pH 5-8 range, it is conceivable that the basic concepts would apply equally well for the stabilization of waste metals in mill tailings piles, wherein conditions can be moderately acidic.

Nash, K. L.

1999-02-26

441

4f-4f hypersensitivity in the absorption spectra and NMR studies on paramagnetic lanthanide chloride complexes with 1,10-phenanthroline in non-aqueous solutions.  

PubMed

The optical absorption and NMR studies of trivalent lanthanide chloride complexes with 1,10-phenanthroline (phen) are presented and discussed. The 1H NMR spectra of the complexes of La, Pr, Nd, Eu and Yb have been studied in methanol-d(4). The resonances of phen in the NMR spectra of the paramagnetic complexes have been shifted to lower as well as higher fields, which is a manifestation of dipolar interaction. The H (2) protons of the heterocyclic amine display broad resonances. The degree of broadening in Pr, Nd, and Yb complexes follows the order Pr < Nd < Yb. The inter- and intra-molecular shift ratios show that the paramagnetic shift is predominantly due to dipolar interaction. The electronic spectra of Pr, Nd, Ho and Er complexes have been investigated in methanol, pyridine, DMSO and DMF, which reveal that the hypersensitive transitions exhibit larger variation in oscillator strength values and band shapes. The change in the coordination geometry of the complexes and relative basicity of ligand are found responsible for oscillator strength and band shape variation. The interelectronic repulsion and covalency parameters show covalent nature of bonding between the metal and the ligand. PMID:12633723

Hussain, H A; Iftikhar, K

2003-03-15

442

Chemical shift imaging: a review.  

PubMed

Chemical shift is the phenomenon that is seen when an isotope possessing a nuclear magnetic dipole moment resonates at a spectrum of resonance frequencies in a given magnetic field. These resonance frequencies, or chemical shifts, depend on the chemical environments of particular nuclei. Mapping the spatial distribution of nuclei associated with a particular chemical shift (e.g., hydrogen nuclei associated with water molecules or with lipid groups) is called chemical shift imaging. Several techniques of proton chemical shift imaging that have been applied in vivo are presented, and their clinical findings are reported and summarized. Acquiring high-resolution spectra for large numbers of volume elements in two or three dimensions may be prohibitive because of time constraints, but other methods of imaging lipid of water distributions (i.e., selective excitation, selective saturation, or variations in conventional magnetic resonance imaging pulse sequences) can provide chemical shift information. These techniques require less time, but they lack spectral information. Since fat deposition seen by chemical shift imaging may not be demonstrated by conventional magnetic resonance imaging, certain applications of chemical shift imaging, such as in the determination of fatty liver disease, have greater diagnostic utility than conventional magnetic resonance imaging. Furthermore, edge artifacts caused by chemical shift effects can be eliminated by certain selective methods of data acquisition employed in chemical shift imaging. PMID:3008543

Brateman, L

1986-05-01

443

Problem of asymmetry in electronic Raman scattering of lanthanide (III) systems  

NASA Astrophysics Data System (ADS)

In this work the influence of surrounding ligands on the asymmetric features of electronic Raman scattering (ERS) in lanthanide ions has been investigated. Within the independent systems model we have developed the theory, which takes into account both the static and dynamic coupling between the lanthanide ion and the ligands. The third-order contributions arising from these mechanisms have been carefully analysed. It is demonstrated that they are able to introduce noticeable corrections to the asymmetry resulting from the theory of Mortensen and Koningstein (ref. 1).

Sztucki, J.; Strek, W.

1988-05-01

444

Selectivity Sequence of Multivalent Lanthanides for Their Separation on Antimonate Based Exchangers  

Microsoft Academic Search

The adsorption of trivalent lanthanide ions, Ln (La, Pr, Nd, Gd, and Er), using two antimonate based exchangers, namely, silicon antimonate (SiSb) and poly(acrylamide titanium antimonate), PAmTA, was studied from their nitrate solutions at pH 3.5 ± 0.1. The formation constants in Ln\\/SiSb and Ln\\/PAmTA systems, logKS1 and logKS2, were calculated for the above mentioned lanthanides. The Kd values of the selected

G. M. Ibrahim; M. I. Ahmad; B. El-Gammal; I. M. El-Naggar

2011-01-01

445

Synthesis and characterisation of bis-cyclen based dinuclear lanthanide complexes.  

PubMed

The design and synthesis of several bis-macrocyclic cyclen (1,4,7,10-tetraazacyclododecane) ligands and their corresponding lanthanum or europium complexes is described; these dinuclear lanthanide systems were made by connecting two macrocyclic cyclen moieties through a rigid, covalent, p-xylylenediamide bridge or a flexible aliphatic hexane bridge. These ligands were subsequently functionalised with six acetamide pendant arms (CONR1R2: R1 = R2 = H or CH3, or R1 = H, R2 = CH3). The corresponding lanthanide bis-complexes were then formed by reaction with La(III) and Eu(III) triflates, yielding overall cationic (+VI charged) complexes. PMID:16604226

Gunnlaugsson, Thorfinnur; Harte, Andrew J

2006-04-21

446

Structures and catalytic properties of triphenylphosphine oxide complexes of scandium and lanthanide triflates  

Microsoft Academic Search

The complexes M(OTf)3(Ph3PO)4 where M=lanthanide metals and scandium have been prepared and characterised in the solid state by single crystal X-ray diffraction, infrared spectroscopy and elemental analysis. All the complexes have the ionic structure [M(OTf)2(Ph3PO)4]+[OTf]?. Single crystal X-ray structures for M=Sc, Nd and Lu are reported. In the complexes of the early lanthanides (La?Nd) the metals are seven-coordinate with one

John Fawcett; Andrew W. G Platt; David R Russell

2002-01-01

447

PREPARATION AND PROPERTIES OF PYRIDINE DICARBOXYLIC ACID COMPLEXES OF THE LANTHANIDES  

Microsoft Academic Search

The preparation and spectroscopic properties of eleven hydrated lanthanide (III) dipicolinate and quinolinate complexes are reported for the first time. The complexes are of three general types: M(dipi)(dipiH)(H2O)4, M(dipiH)3(H2O) and M(quin)(quinH)(H2O)3 [where M =lanthanide (III); dipiH2 =pyridine-2,6-dicarboxylic acid (dipicolinic acid); quinH2 =pyridine-2, 3-dicarboxylic acid (quinolinic acid)], and evidence is presented which indicates that they may be six-coordinate.

A. Anagnostopoulos

1975-01-01

448

Methodical aspects of blood coagulation measurements in birds applying commercial reagents--a pilot study.  

PubMed

The aim of this study was to examine the suitability of commercially available reagents for measurements of coagulation parameters in citrated plasma from birds. Therefore, plasma samples of 17 healthy donor birds of different species were used to determine prothrombin time (PT), activated partial thromboplastin time (aPTT) and thrombin time (TT) applying various commercial reagents which are routinely used in coagulation diagnostics in humans and mammals. A PT reagent based on human placental thromboplastin yielded not only shorter clotting times than a reagent containing recombinant human tissue factor (median 49 vs. 84 s), but also showed a minor range of distribution of values (43-55 s vs. 30-147 s, minimum-maximum, n = 5 turkeys). An aPTT reagent containing kaolin and phospholipids of animal origin delivered the shortest clotting times and the lowest range of variation in comparison to three other reagents of different composition. However, even when this reagent was used, aPTTs were partially extremely long (> 200 s). Thrombin time was 38 s (28-57 s, n = 5 chicken) when measured with bovine thrombin at a final concentration of 2 IU thrombin/ ml. Coefficients of variation for within-run precision analysis (20 repetitions) of PT was 8.0% and 4.7% for aPTT measurements using selected reagents of mammalian origin. In conclusion, of the commercially available reagents tested, a PT reagent based on human placental thromboplastin and an aPTT reagent including rabbit brain phospholipid and kaolin, show some promise for potential use in birds. PMID:25080826

Guddorf, Vanessa; Kummerfeld, Norbert; Mischke, Reinhard

2014-01-01

449

The induction of the oxidative burst in Elodea densa by sulfhydryl reagents is independent of the inhibiting action of these reagents on photosynthesis  

Microsoft Academic Search

The sulfhydryl group-reagents NEM (N-ethylmaleimide), p-CMBS (parachloromercurybenzenesulfonate), Ag+ and Cu2+ inhibit very rapidly and drastically photosynthetic O2 evolution inElodea densa leaves. This effect has been compared with that of the same reagents in inducing in non illuminated leaves a strong increase\\u000a of O2 consumption (oxygen burst), presumably due to activation of some plasma membrane redox systems. The results suggest that

Francesco Albergoni; Pietro Rocco; Mario Bellando; Silvano Sacco; Maria Teresa Marrè; E. Marrè

1996-01-01

450

Formation and reactions of alkylzinc reagents in room-temperature ionic liquids.  

PubMed

[reaction: see text] The presence of a suitable amount of bromide or chloride ions was found to be critical in forming the alkylzinc reagents from alkyl iodides and zinc metal in the room-temperature ionic liquid, N-butylpyridinium tetrafluoroborate. Beta-hydride transfer in the reactions of butylzinc reagents with aldehydes can also be reduced by a bromide ion. PMID:16323854

Law, Man Chun; Wong, Kwok-Yin; Chan, Tak Hang

2005-12-01

451

Unexpected Reactivity of the Burgess Reagent with Thiols: Synthesis of Symmetrical Disulfides  

E-print Network

or via substitution to form inner salt 25. Intermediates 25 or 27, required for intramolecular E2 elimina thudlicky@brocku.ca ReceiVed January 26, 2007 Reaction of the Burgess reagent with a series of aliphatic in the reactions of aliphatic thiols. Since its discovery in the late 1960s, the Burgess reagent1 has been used

Hudlicky, Tomas

452

Sample\\/reagent adsorption on alumina versus Pyrex substrates of microfabricated electrochemical sensors  

Microsoft Academic Search

Platinum redox sensors have been microfabricated for potentiometric detection in diffusional microtitration of microliter-size fluid samples. Two different materials, alumina ceramic and Pyrex glass, have been studied for their suitability as sensor substrates. Adsorptions of reagent and\\/or sample on an alumina ceramic substrate and a Pyrex glass substrate are compared. Using iodimetric redox titration, significant adsorption of both reagent and

R. S. Diefes; K. Y. Hui; L. Dudik; C. C. Liu; M. Gratzl

1996-01-01

453

An Alternative Approach for Preparing and Standardizing Some Common Aqueous Reagents Used in an Undergraduate Laboratory  

ERIC Educational Resources Information Center

A guide for instructors and laboratory assistants to prepare some common aqueous reagents used in an undergraduate laboratory is presented. Dilute reagents consisting of H[superscript +](aq), I[subscript 3][superscript-](aq), Ce[superscript 4+](aq), and Ag[superscript+](aq) were prepared by electrolytic oxidation of respective precursors.…

Melaku, Samuel; Dabke, Rajeev B.

2014-01-01

454

CLAY AND CLAY-SUPPORTED REAGENTS IN ORGANIC SYNTHESES: JOURNAL ARTICLE  

EPA Science Inventory

NRMRL-CIN-0866 Varma*, R.S. Clay and Clay-Supported Reagents in Organic Syntheses. Tetrahedron (Sir J.E. Baldwin (Ed.), Elsevier Science Ltd) 58 (7):1235-1255 (2002). EPA/600/J-02/032. 10/28/1999 CLAY AND CLAY-SUPPORTED REAGENTS HAVE BEEN USED EXTENSIVELY FOR SYNTHETIC ORGA...

455

Derivatizing Reagents Based on Ferrocene for HPLC-Ecd Determination of Peptides and Proteins  

Microsoft Academic Search

Several ferrocenic compounds for derivatization of peptides and proteins were synthesized and then tested by reaction with bovine serum albumin (BSA). The reactivity of the reagents and the electroactivity of the derivatized BSA were estimated by the height of the ECD-signal after an HPLC analysis run. The most suitable reagent was 3-ferrocenylpropionic anhydride which reacts with BSA within 15 minutes

Heiner Eckert; Marianne Koller

1990-01-01

456

Reactivity of the actinoid-carbon bond: alkyluranium compounds as selective nucleophilic reagents in organic synthesis  

SciTech Connect

Stable tris(bis(trimethylsilyl)amido)methyluranium is a very highly selective nucleophilic Grignard-like reagent in chemo- and stereoselective alkylation reactions of carbonyl compounds. Related tris(bis(trimethylsilyl)amido)-trichloro-, and cyclopenadienyldichloroalkyluranium complexes are less selective reagents. 16 references, 7 tables.

Dormond, A.; Aaliti, A.; Moiese, C.

1988-03-04

457

Lanthanide contraction and magnetism in the heavy rare earth elements.  

PubMed

The heavy rare earth elements crystallize into hexagonally close packed (h.c.p.) structures and share a common outer electronic configuration, differing only in the number of 4f electrons they have. These chemically inert 4f electrons set up localized magnetic moments, which are coupled via an indirect exchange interaction involving the conduction electrons. This leads to the formation of a wide variety of magnetic structures, the periodicities of which are often incommensurate with the underlying crystal lattice. Such incommensurate ordering is associated with a 'webbed' topology of the momentum space surface separating the occupied and unoccupied electron states (the Fermi surface). The shape of this surface-and hence the magnetic structure-for the heavy rare earth elements is known to depend on the ratio of the interplanar spacing c and the interatomic, intraplanar spacing a of the h.c.p. lattice. A theoretical understanding of this problem is, however, far from complete. Here, using gadolinium as a prototype for all the heavy rare earth elements, we generate a unified magnetic phase diagram, which unequivocally links the magnetic structures of the heavy rare earths to their lattice parameters. In addition to verifying the importance of the c/a ratio, we find that the atomic unit cell volume plays a separate, distinct role in determining the magnetic properties: we show that the trend from ferromagnetism to incommensurate ordering as atomic number increases is connected to the concomitant decrease in unit cell volume. This volume decrease occurs because of the so-called lanthanide contraction, where the addition of electrons to the poorly shielding 4f orbitals leads to an increase in effective nuclear charge and, correspondingly, a decrease in ionic radii. PMID:17410171

Hughes, I D; Däne, M; Ernst, A; Hergert, W; Lüders, M; Poulter, J; Staunton, J B; Svane, A; Szotek, Z; Temmerman, W M

2007-04-01

458

Lanthanide contraction and magnetism in the heavy rare earth elements  

NASA Astrophysics Data System (ADS)

The heavy rare earth elements crystallize into hexagonally close packed (h.c.p.) structures and share a common outer electronic configuration, differing only in the number of 4f electrons they have. These chemically inert 4f electrons set up localized magnetic moments, which are coupled via an indirect exchange interaction involving the conduction electrons. This leads to the formation of a wide variety of magnetic structures, the periodicities of which are often incommensurate with the underlying crystal lattice. Such incommensurate ordering is associated with a `webbed' topology of the momentum space surface separating the occupied and unoccupied electron states (the Fermi surface). The shape of this surface-and hence the magnetic structure-for the heavy rare earth elements is known to depend on the ratio of the interplanar spacing c and the interatomic, intraplanar spacing a of the h.c.p. lattice. A theoretical understanding of this problem is, however, far from complete. Here, using gadolinium as a prototype for all the heavy rare earth elements, we generate a unified magnetic phase diagram, which unequivocally links the magnetic structures of the heavy rare earths to their lattice parameters. In addition to verifying the importance of the c/a ratio, we find that the atomic unit cell volume plays a separate, distinct role in determining the magnetic properties: we show that the trend from ferromagnetism to incommensurate ordering as atomic number increases is connected to the concomitant decrease in unit cell volume. This volume decrease occurs because of the so-called lanthanide contraction, where the addition of electrons to the poorly shielding 4f orbitals leads to an increase in effective nuclear charge and, correspondingly, a decrease in ionic radii.

Hughes, I. D.; Däne, M.; Ernst, A.; Hergert, W.; Lüders, M.; Poulter, J.; Staunton, J. B.; Svane, A.; Szotek, Z.; Temmerman, W. M.

2007-04-01

459

First examples of ternary lanthanide succinate complexes: hydro-solvothermal syntheses and structures of lanthanide coordination polymers of succinic acid and 1,10-phenanthroline  

NASA Astrophysics Data System (ADS)

Three new supramolecular lanthanide coordination polymers, {[Eu(SA) 1.5(phen)]·H 2O} n ( 1), and [Ln(SA) 1.5(phen)] n [Ln=Er ( 2); Yb ( 3)] were obtained by hydro-solvothermal reactions of lanthanide chlorides with succinic acid (H 2SA) and 1,10-phenanthroline (phen), and characterized by single crystal X-ray diffraction, elemental analysis and IR spectrum. Complexes 1- 3 also have 2D networks which are further architectured to form 3D supramolecular structures by hydrogen bonds and ?-? aromatic interactions, of which 1 has 1D channels. The H 2SA ligands are all completely deprotonated and exhibit tetra- and pentadentate coordination modes in the titled complexes. The photoluminescence property of 1 was investigated.

Liu, Chong-Bo; Wen, Hui-Liang; Tan, Sheng-Shui

2006-08-01

460

Smart bombing a single targeted cell with femtogram order reagents using laser-induced shockwave technique  

NASA Astrophysics Data System (ADS)

Injection and delivery of small amount reagent in aqueous solution for cell chip was performed utilizing regeneratively amplified femtosecond laser system. In our new trial, the reagent integrated on a solid strip are released and delivered to targeted cells with the femutosecond laser-induced impulsive-force. The reagent was fixed in poly(vinyl alcohol) or polystyrene film on a glass-substrate strip. When a single pulsed femtosecond laser was focused in the solution, the film near the focal point was fragmented and the reagent was dispersed in 45-?m ? area at 50 ?m from the surface of the reagent strip. As examples cardiomyocyte beating cells of P19CL6 were bombed with epinephrine and acetylcholine, and as a result the beating ratio of the cells were quickly stimulated and suppressed, respectively. The results demonstrate that the present method is a promising key nano/micro technology for diagnosis and drug discovery.

Okano, Kazunori; Takizawa, Noriko; Uwada, Takayuki; Hosokawa, Yoichiroh; Masuhara, Hiroshi

2008-02-01

461

High-load, oligomeric dichlorotriazine (ODCT): A versatile ROMP-derived reagent and scavenger  

PubMed Central

A new high-load, soluble oligomeric dichlorotriazine (ODCT) reagent derived from ring-opening metathesis polymerization (ROMP) is reported as an effective coupling reagent, scavenger of nucleophilic species and activator of DMSO for the classic Swern oxidations. Two variants of this reagent 2GODCT 4 and 1GODCT 16, possessing theoretical loads of 5.3 mmol/g and 7.3 mmol/g, respectively, have been synthesized. Preparation was accomplished via simple synthetic protocols affording free flowing powders, amenable for large-scale production. Removal of the spent oligomeric reagent was achieved via either precipitation of the spent reagent or simple filtration utilizing a silica SPE, followed by solvent removal, to deliver products in excellent yield and purity. In addition, the corresponding norbornenyl monomer 3 was successfully demonstrated in a couple-ROMP-filter protocol utilizing in-situ polymerization, achieving comparable results versus the corresponding oligomeric variant. PMID:18937412

Rolfe, Alan; Probst, Donald A.; Volp, Kelly A.; Omar, Iman; Flynn, Daniel L.; Hanson, Paul R.

2011-01-01

462

Application of Fenton's reagent combined with sawdust on the dewaterability of oily sludge.  

PubMed

Fenton's reagent and sawdust were used on the dewaterability of the raw oily sludge in this study. The result shows that the combination of the two treatment processes is favorable, although the application of Fenton's reagent only is not so good. The capillary suction time (CST) and specific resistance to filtration (SRF) were used to evaluate the effect of dewaterability of the raw oily sludge, and the CST and SRF values are reduced from 1,760 s and 13.8?×?10(12) m/kg to 185 s and 1.5?×?10(12) m/kg, respectively. The dry matter contents of sludge cakes and properties of the supernatant all gained when using only the Fenton's reagent and when using the combined treatment with Fenton's reagent and sawdust respectively were investigated. The results indicate that the oily sludge is more suitable for further treatment after combined process with Fenton's reagent and sawdust. PMID:24870288

Guo, Hao; Feng, Suping; Jiang, Jun; Zhang, Miao; Lin, Hai; Zhou, Xiaoyan

2014-09-01

463

Influence of Schiff base and lanthanide metals on the synthesis, stability, and reactivity of monoamido lanthanide complexes bearing two Schiff bases.  

PubMed

The monoamido lanthanide complexes stabilized by Schiff base ligand L(2)LnN(TMS)(2) (L = 3,5-Bu(t)(2)-2-(O)-C(6)H(2)CH?N-8-C(9)H(6)N, Ln = Yb (1), Y (2), Eu (3), Nd (4), and La (5)) were synthesized in good yields by the reactions of Ln[N(TMS)(2)](3) with 1.8 equiv of HL in hexane at room temperature. It was found that the stability of 1-5 depends greatly on the size of the lanthanide metals with the increasing trend of Yb ? Y < Nd < La. The amine elimination of Ln[N(TMS)(2)](3) with the bulky bidentate Schiff base HL' (L' = 3,5-Bu(t)(2)-2-(O)-C(6)H(2)CH?N-2,6-Pr(i)(2)-C(6)H(3)) afforded the monoamido lanthanide complexes L'(2)LnN(TMS)(2) (Ln = Yb (9), Y (10), Nd (11), and La (12)). While the amine elimination with the less bulky Schiff base HL'' (L'' = 3,5-Bu(t)(2)-2-(O)-C(6)H(2)CH?N-2,6-Me(2)-C(6)H(3)) yielded the desired monoamido complexes with the small metals of Y and Yb, L''(2)LnN(TMS)(2) (Ln = Yb (13) and Y (14)), and the more stable tris-Schiff base complexes with the large metals of La and Nd, yielded L''(3)Ln as the only product. Complexes 1-14 were fully characterized including X-ray crystal structural analysis. Complexes 1-5, 10, and 14 can serve as the efficient catalysts for addition of amines to carbodiimides, and the catalytic activity is greatly affected by the lanthanide metals with the active sequence of Yb < Y < Eu ? Nd ? La. PMID:21319780

Han, Fubin; Teng, Qiaoqiao; Zhang, Yong; Wang, Yaorong; Shen, Qi

2011-03-21

464

The benzoate\\/nitrate\\/2,2?:6?,2?-terpyridine ‘blend’ in lanthanide(III) chemistry: Relevance to the separation of lanthanides and actinides by solvent extraction  

Microsoft Academic Search

In an effort to better understand the nature of the species which may be involved in the selective extraction of actinides over the lanthanides – relevant to nuclear reprocessing – by 2,2?:6?,2?-terpyridine (terpy)-type ligands, in synergistic combination with a liphophilic carboxylic acid coextractant, the PrIII\\/PhCO2-\\/NO3-\\/terpy reaction system has been investigated. The investigation resulted in the isolation of the dinuclear complex

Argyro Messimeri; Christos Papadimitriou; Catherine P. Raptopoulou; Albert Escuer; Spyros P. Perlepes; Athanassios K. Boudalis

2007-01-01

465

Energy transfer in coumarin-sensitised lanthanide luminescence: investigation of the nature of the sensitiser and its distance to the lanthanide ion.  

PubMed

A series of lanthanide complexes [Ln(dpxCy)3](3-) have been synthesised. The ligands are composed of a coordinating dipicolinic acid backbone decorated with a polyoxyethylene arm fitted with a coumarin moiety at its extremity. The nature of the coumarin as well as the length of the linker have been varied. Upon excitation at 320 nm, the coumarin exclusively acts as an antenna while the dipicolinic acid core is not excited. Upon excitation below 300 nm, both parts are excited. With europium as a metal centre, the relaxation of the europium ion (intrinsic quantum yield ?(Eu)(Eu) and radiative lifetime ?r) is constant for all the studied ligands. Therefore, the observed differences in overall quantum yield (?(Eu)(L)) in such systems come exclusively from the variation of the terminal coumarin. The overall quantum yields of the studied complexes are low (?(Eu)(L) < 2% in aqueous solution). In order to rationalise the mechanism of the energy transfer and to improve the sensitisation efficiency (?sens), the distance between the coumarin sensitiser and the lanthanide centre was explored in solution and compared to the solid state. In the solid state, a dramatic effect was confirmed, with an improvement of 80% in the quantum yield ?(Eu)(L) for short linkers ((-CH2CH2O-)n with n = 1 compared to n = 3). By monitoring the lifetime decay of the excited state of the lanthanide cation with nanosecond vs. microsecond time-resolved spectroscopy at low temperature, the sensitisation of the lanthanide ions by coumarin derivatives was demonstrated to mainly occur through the singlet excited state of the coumarin and not via the usual triplet pathway. No evidence of a different behaviour at room temperature was found by transient triplet-triplet absorption spectroscopy. PMID:23959569

Andres, Julien; Chauvin, Anne-Sophie

2013-10-14

466

Synergistic effects in solvent-extraction systems based on alkylsalicylic acids. III. Extraction of the trivalent lanthanides and yttrium from chloride media in the presence of dialkyl and diaryl sulphoxides  

SciTech Connect

Dialkyl and diaryl sulphoxides were found to cause synergistic shifts in the pH{sub 50} values for the extraction of the trivalent lanthanides and yttrium from sodium chloride media by solutions of alkylsalicylic acids in xylene. The extent of the synergistic shift for a given sulphoxide increases with increasing steric bulk of the alkylsalicylic acid used. With the homologous series of dialkyl sulphoxides R{sub 2}SO, where R = n-butyl, n-hexyl, and n-octyl, there is little variation in the size of the synergistic shift for a given alkylsalicylic acid. For a series of sulphoxides containing similar numbers of carbon atoms, the extent of the shift increases with the introduction of alicyclic rings, but decreases when aromatic rings are introduced, for example, in the order of R: cyclohexyl > n-hexyl > phenyl, although the effect is not very marked. For a given extractant mixture, the pH{sub 50} values decrease from lanthanum to samarium and then increase from samarium to lutetium. The separation between the pH{sub 50} values for lanthanum and lutetium increases with increasing steric bulk of both the alkylsalicylic acid (HA) and the sulphoxide (L), but the separations between adjacent lanthanides are in all cases too small to be of any practical use. Slope-analysis treatment of metal-distribution data, and measurements of the solubility of the neodymium-alkylsalicylic acid complex in xylene solutions of the sulphoxides are consistent with the extraction of a mixed-ligand complex of the type NdA{sub 3}L{sub 2}. 22 refs., 4 figs., 4 tabs.

Preston, J.S.; Preez, A.C. du [Mintek, Randburg (South Africa)

1996-08-01

467

Solvothermal synthesis and structures of lanthanide-organic sandwich coordination polymers with 4,4?-biphenyldicarboxylic acid  

Microsoft Academic Search

First examples of lanthanide coordination polymers with 4,4?-biphenyldicarboxylic acid (4,4?-H2bpdc), Ln(4,4?-Hbpdc)(4,4?-bpdc)(H2O)2 (Ln=Pr(1), Eu(2), Gd(3)) and Er(4,4?-bpdc)1.5(H2O)2 (4) were prepared by the solvothermal synthesis. Crystallographic data show that complexes 1–3 are isostructural and each lanthanide(III) ion is coordinated to six 4,4?-Hbpdc ligands, and display 3D sandwich structure with lanthanide ion layers and organic ligand layers alternately linking up with each other.

Yi-Bo Wang; Wen-Juan Zhuang; Lin-Pei Jin; Shao-Zhe Lu

2004-01-01

468

Shift scheduling for tank trucks  

Microsoft Academic Search

In this paper we deal with shift scheduling of tank trucks for a small oil company. Given are a set of tank trucks with different characteristics and a set of drivers with different skills. The objective is to assign a feasible driver to every shift of the tank trucks such that legal and safety restrictions are satisfied, the total working

Sigrid Knust; Elisabeth Schumacher

2011-01-01

469

A Rare Earth-DOTA-Binding Antibody: Probe Properties and Binding Affinity across the Lanthanide Series  

E-print Network

A Rare Earth-DOTA-Binding Antibody: Probe Properties and Binding Affinity across the Lanthanide affinity and exquisite specificity.1 An antibody that binds rare earth complexes selectively could be used The rare earths are rich in probe properties, such as the paramagnet- ism of Gd, the luminescence of Tb

Fisher, Andrew J.

470

Luminescent lanthanide metal-organic frameworks with a large SHG response.  

PubMed

A family of new luminescent lanthanide MOFs have been synthesized and display a strong second-harmonic generation response, which is 6.0 times that of KDP and phase matchable. The LnMOFs also exhibit typical luminescence emissions with high quantum yields (up to 70.0% for Tb). PMID:23047328

Dang, Song; Zhang, Jian-Han; Sun, Zhong-Ming; Zhang, Hongjie

2012-11-21

471

Catalytic activity of solvated and unsolvated lanthanide halides in Friedel–Crafts acylations  

Microsoft Academic Search

Anhydrous lanthanide halides — chlorides and bromides — can act as homogeneous catalysts of Friedel–Crafts acylations. The catalytic activity is related to the solubility of these anhydrous salts. More soluble THF or dioxane (Diox.) neodymium and samarium adducts are more active catalysts.

Denise Barbier-Baudry; Alain Dormond; Stéphanie Richard; Jean Roger Desmurs

2000-01-01

472

Lanthanides extraction processes in molten fluoride media: Application to nuclear spent fuel reprocessing  

Microsoft Academic Search

This paper describes four techniques of extraction of lanthanide (Ln) elements from molten salts in the general frame of reprocessing nuclear wastes; one of them is chemical: the precipitation of Ln ions in insoluble compounds (oxides or oxyfluorides); the others use electrochemical methodology in molten fluorides for extraction and measurement of the progress of the processes: first electrodeposition of pure

P. Taxil; L. Massot; C. Nourry; M. Gibilaro; P. Chamelot; L. Cassayre

2009-01-01

473

Lanthanide compounds as environmentally-friendly corrosion inhibitors of aluminium alloys: a review  

Microsoft Academic Search

Currently, chromates are among the most common substances used as inhibitors or incorporated in anticorrosive pretreatments of aluminium alloys. However, these compounds are highly toxic and their use produces serious environmental hazards. Consequently, an intense research effort is being undertaken to replace chromates by more ecological compounds. In recent years, several authors have begun studies of the behaviour of lanthanide

M. Bethencourt; F. J. Botana; J. J. Calvino; M. Marcos; M. A. RodrÍguez-Chacón

1998-01-01

474

On the magnetism of Ln2/3Cu3Ti4O12 (Ln = lanthanide)  

NASA Astrophysics Data System (ADS)

The magnetic and thermodynamic properties of the complete Ln2/3Cu3Ti4O12 series were investigated. Here Ln stands for the lanthanides La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb. All the samples investigated crystallize in the space group Imbar{3} with lattice constants that follow the lanthanide contraction. The lattice constant of the Ce compound reveals the presence of Ce4+ leading to the composition Ce1/2Cu3Ti4O12. From magnetic susceptibility and electron-spin resonance experiments it can be concluded that the copper ions always carry a spin S = 1/2 and order antiferromagnetically close to 25 K. The Curie-Weiss temperatures can approximately be calculated assuming a two-sublattice model corresponding to the copper and lanthanide ions, respectively. It seems that the magnetic moments of the heavy rare earths are weakly coupled to the copper spins, while for the light lanthanides no such coupling was found. The 4 f moments remain paramagnetic down to the lowest temperatures, with the exception of the Tm compound, which indicates enhanced Van-Vleck magnetism due to a non-magnetic singlet ground state of the crystal-field split 4 f manifold. From specific-heat measurements we accurately determined the antiferromagnetic ordering temperature and obtained information on the crystal-field states of the rare-earth ions.

Dittl, A.; Krohns, S.; Sebald, J.; Schrettle, F.; Hemmida, M.; Krug von Nidda, H.-A.; Riegg, S.; Reller, A.; Ebbinghaus, S. G.; Loidl, A.

2011-02-01

475

Tetrametallic lanthanide(iii) phosphonate cages: synthetic, structural and magnetic studies.  

PubMed

The synthesis, structures and magnetic properties of a family of lanthanide complexes containing phosphonate ligands are reported. Reaction of hydrated lanthanide nitrate and (t)butylphosphonic acid under reflux conditions in iso-butanol, in the presence of pivalic acid as a co-ligand produced five new lanthanide complexes; pyridine (py) was present as a base. The compounds formed are tetrametallic, with the general formula [pyH]4[Ln4(?3-OH)(O3P(t)Bu)3(HO3P(t)Bu)(O2C(t)Bu)2(NO3)6] where Ln = Gd(III), ; Tb(III), ; Dy(III), ; Ho(III), and Er(III), . The metal sites within the complexes lie on the vertices of a triangle-based pyramid, with phosphonate ligands on the triangular faces linking the apical Ln site to the Ln sites in the base. Each lanthanide(iii) site is eight-coordinate. Magnetic studies of the compounds show a decline in the product ?MT with T; modelling the behaviour of shows anti-ferromagnetic exchange between Gd(III) centres within the triangle with a negligible interaction to the fourth Gd(III) centre at the apex of the trigonal pyramid. PMID:25310820

Zangana, Karzan H; Pineda, Eufemio Moreno; Winpenny, Richard E P

2014-10-28

476