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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

Enantiomeric differentiation of bornyl acetate by 13C-NMR using a chiral lanthanide shift reagent.  

PubMed

The enantiomeric differentiation of bornyl acetate was carried out by 13C-NMR spectroscopy using a chiral lanthanide shift reagent. The technique was successfully applied to the determination of the enantiomer of bornyl acetate present in the essential oil of Inula graveolens. PMID:12892421

Baldovini, Nicolas; Tomi, Félix; Casanova, Joseph

3

Enantiomeric differentiation of acyclic terpenes by 13C NMR spectroscopy using a chiral lanthanide shift reagent.  

PubMed

The 13C NMR behaviour of ten acyclic terpene alcohols was examined in the presence of a chiral lanthanide shift reagent (CLSR). For each alcohol, we measured the lanthanide-induced shift (LIS) on the signals of the carbons and the splitting of some signals, which allowed the enantiomeric differentiation. As expected, the LIS decreased with the number of bonds between the binding function and the considered carbon. The enantiomeric splitting is observed for several signals in the spectrum of each compound. The influence of the hindrance of the binding function (primary, secondary or tertiary alcohol) and that of the stereochemistry of the double bonds is discussed. PMID:15593244

Blanc, Marie-Cécile; Bradesi, Pascale; Casanova, Joseph

2005-02-01

4

Synthesis and Multinuclear Lanthanide Shift Reagent NMR Analysis of 1- and 2-Adamantanol: An Advanced Undergraduate Laboratory Project.  

ERIC Educational Resources Information Center

|Reports on a project used in a junior-level laboratory in which students prepare two alcohols, characterize these compounds, and use a shift reagent for structure determination and peak assignment. Background information, materials needed, procedures used, and typical results obtained are included. (JN)|

Schaeffer, Charles D., Jr.; Yoder, Claude H.

1985-01-01

5

Synthesis and Multinuclear Lanthanide Shift Reagent NMR Analysis of 1- and 2-Adamantanol: An Advanced Undergraduate Laboratory Project.  

ERIC Educational Resources Information Center

Reports on a project used in a junior-level laboratory in which students prepare two alcohols, characterize these compounds, and use a shift reagent for structure determination and peak assignment. Background information, materials needed, procedures used, and typical results obtained are included. (JN)

Schaeffer, Charles D., Jr.; Yoder, Claude H.

1985-01-01

6

The Studies of 13C NMR Chemical Shifts and Induced Lanthanide Shift Reagent Cis-trans Isomerization of N-Cinamylidene-hexyl, t-butyl and Substituted Aryl-Amines  

Microsoft Academic Search

The Carbon-13 chemical shifts of N-Cinamylidenehexyl, t-butyl and sixteen substituted aryl amines were analysed. The lanthanide induced carbon-13 chemical shifts of the cis and trans of four N-cinamylidene substituted anilines were analysed. The spectra N-cinamylidene hexylamine showed only the trans form. The cis\\/trans ratio of N-cinamylidene aryl amines increased as the LSR concentration increased.

Jasim M. A. Al-Rawi; Layla M. N. Saleem

1991-01-01

7

Structure elucidation with lanthanide-induced shifts 5. Evaluation of the binding ability of various functional groups  

Microsoft Academic Search

The equilibrium binding constants have been evaluated for the association in CCl4 of the lanthanide shift reagent. Eu(fod)3, with a series of adamantane derivatives containing a variety of different functional groups. It is shown that if steric effects are held constant the binding abilities of the adamantane derivatives exhibit a good correlation with the proton affinities of the methyl analogs

Douglas J. Raber; Milton D. Johnston; Catherine M. Campbell; Anne Guida; F. Jackson; Christopher M. Janks; Joseph W. Perry; Gary J. Propeck; Nancy K. Raber; Michael A. Schwalke; Pamela M. Sutton

1980-01-01

8

Proton and carbon lanthanide-induced shifts in aqueous alanine. Evidence for structural changes along the lanthanide series  

Microsoft Academic Search

Proton and carbon lanthanide-induced shifts are reported for aqueous alanine at pH 3. A comparison of the measured shifts with theoretical values provides evidence for changes in the coordination behavior of alanine between Tb\\/sup 3 +\\/ and DY\\/sup 3 +\\/. An apparent stability constant (K⁠= 0.7 +- 0.1 M⁻¹) was measured for eight lanthanide ions and found insensitive to

A. Dean Sherry; E. Pascual

1977-01-01

9

Bulk magnetic susceptibility shifts in NMR studies of compartmentalized samples: use of paramagnetic reagents.  

PubMed

The bulk magnetic susceptibility (BMS) shift of a nuclear resonance frequency caused by a paramagnetic compound is of importance in vivo NMR, both magnetic resonance spectroscopy and magnetic resonance imaging. However, since it is a rather complicated phenomenon, it has been the source of many misinterpretations in the literature. We have reworked and organized the theory of the BMS shift. This includes accounting for the important effects of local susceptibility. We have conducted experiments on phantom samples in order to illustrate the principles involved. Our phantoms consist of capillaries and coaxial cylinders. They simulate the situations of blood vessels oriented parallel and perpendicular to the magnetic field and the interstitial spaces surrounding them. In most of our experiments, the paramagnetic compound was one of several different hyperfine shift reagents for cation resonances. These were chosen to cover a range of potencies, in both magnitude and sign, of the shifts they produce. However, we also used a reagent which was incapable of inducing a hyperfine shift and thus could cause only a BMS shift. Although we report only 23Na spectra in this paper, the latter samples simulate the cases where one observes the water 1H resonance in experiments employing hyperfine shift reagents for cations. There have been a number of such investigations recently reported in the literature. The principles considered in this paper allow us to offer new interpretations for the results of several experiments published in the last few years. PMID:2156125

Chu, S C; Xu, Y; Balschi, J A; Springer, C S

1990-02-01

10

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

11

( S)- ?-methoxyphenyl acetic acid : a new NMR chiral shift reagent for the stereochemical analysis of sulfoxides  

Microsoft Academic Search

The use of (S)-?-methoxyphenyl acetic acid (MPAA) as a general chiral 1H NMR shift reagent for the stereochemical analysis of sulfoxides is demonstrated. Using this methodology, both the enantiomeric purity and the absolute configuration of a wide variety of sulfoxides can be determined.

Herbert L. Holland; Frances M. Brown

1995-01-01

12

NMR chemical shift reagents in structural determination of lipid derivatives: II. Methyl petroselinate and methyl oleate  

Microsoft Academic Search

Whentris(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octaneodionato)europium (III)—Eu(fod)3—forms a complex with a sufficiently basic functional group in a donor molecule, the change in the magnetic environment of\\u000a protons near the coordination site causes their nuclear magnetic resonance (NMR) signals to shift to different positions.\\u000a Consequently Eu(fod)3 and other compounds that similarly affect NMR signals have been designated chemical shift reagents (csr). Because of their\\u000a ability to

John P. Wineburg; Daniel Swern

1972-01-01

13

19F NMR based pH probes: lanthanide(III) complexes with pH-sensitive chemical shifts.  

PubMed

Experimental measurements and theoretical analysis of magnetic properties, structural dynamics and acid-base equilibria for several lanthanide(III) complexes with tetraazacyclododecane derivatives as 19F NMR chemical shift pH probes are presented; pKa values vary between 6.9 and 7.7, with 18 to 40 ppm chemical shift differences between the acidic and basic forms for Ho(III) complexes possessing T1 values of 10 to 30 ms (4.7-9.4 T, 295 K). PMID:18506228

Kenwright, Alan M; Kuprov, Ilya; De Luca, Elena; Parker, David; Pandya, Shashi U; Senanayake, P Kanthi; Smith, David G

2008-05-01

14

Application of L-proline derivatives as chiral shift reagents for enantiomeric recognition of carboxylic acids.  

PubMed

Four proline-derived chiral receptors 5-8 were readily synthesized starting from L-proline. The enantiomeric recognition ability of chiral receptors was examined with a series of carboxylic acids by (1) H NMR spectroscopy. The molar ratio and the association constants of the chiral compounds with each of the enantiomers of guest molecules were determined by using Job plots and a nonlinear least-squares fitting method, respectively. The Job plots indicate that the hosts form 1:1 instantaneous complexes with all guests. The receptors exhibited different chiral recognition abilities toward the enantiomers of racemic guests. Among the chiral receptors used in this study, prolinamide 6 was found to be the best chiral shift reagent and is effective for the determination of the enantiomeric excess of chiral carboxylic acids. PMID:21472784

Naziroglu, Hayriye Nevin; Durmaz, Mustafa; Bozkurt, Selahattin; Sirit, Abdulkadir

2011-04-06

15

Aqueous shift reagents for high-resolution cation NMR. VI. Titration curves for in vivo 23Na and 1H2O MRS obtained from rat blood.  

PubMed

Frequency shift/concentration calibration curves applicable to the use of shift reagents (SRs) for in vivo 23Na MRS studies can be obtained from experiments with whole blood. Here, they are reported for titrations of rat blood with the SRs DyTTHA3- and TmDOTP5-. There are a number of considerations that must be made in order to derive accurate calibration curves from the experimental data. These include the effects of bulk magnetic susceptibility (BMS, since the SRs are paramagnetic), the effects of water flux (since addition of the SR stock solution to blood renders the plasma hyperosmotic), and the consequences of restricted distribution of the SR anion in the erythrocyte suspension. We give in some detail the BMS shift theory that obtains in this case and show also how it applies to excised perfused organ as well as in vivo studies. Also, we report significant effects of adjuvant Ca2+ additions in the TmDOTP5- titrations. These are very important to the successful use of this SR in vivo. Finally, our considerations of BMS lead naturally to an understanding of its manifestations in the shifts of the 1H2O resonance frequencies of cell suspensions and tissues induced by SRs. Since these are being increasingly reported, and often misinterpreted, we devote an experiment and some discussion to this subject. We show that this phenomenon cannot be used to quantitatively discriminate intra- and extracellular 1H2O signals. PMID:8457429

Albert, M S; Huang, W; Lee, J H; Balschi, J A; Springer, C S

16

The use of shift reagents in ion mobility-mass spectrometry: studies on the complexation of an active pharmaceutical ingredient with polyethylene glycol excipients.  

PubMed

Gas-phase ion mobility studies of mixtures containing polyethylene glycols (PEG) and an active pharmaceutical ingredient (API), lamivudine, have been carried out using electrospray ionization-ion mobility spectrometry-quadrupole-time-of-flight mass spectrometry (ESI-IMS-Q-TOF). In addition to protonated and cationized PEG oligomers, a series of high molecular weight ions were observed and identified as noncovalent complexes formed between lamivudine and PEG oligomers. The noncovalent complex ions were dissociated using collision induced dissociation (CID) after separation in the ion mobility drift tube to recover the protonated lamivudine free from interfering matrix ions and with a drift time associated with the precursor complex. The potential of PEG excipients to act as "shift reagents," which enhance selectivity by moving the mass/mobility locus to an area of the spectrum away from interferences, is demonstrated for the analysis of lamivudine in a Combivir formulation containing PEG and lamivudine. PMID:18974011

Howdle, Mark D; Eckers, Christine; Laures, Alice M-F; Creaser, Colin S

2008-10-09

17

Progress in Lanthanides as Luminescent Probes  

Microsoft Academic Search

Lanthanides have recently found applications in different fields of biomolecular and medical research. Luminescent lanthanide chelates have created interest mainly due to their unique luminescent properties, such as their long Stokes’ shift and exceptional decay times allowing efficient temporal discrimination of background interferences in the assays, such as immunoassays. Recently, new organometallic complexes have been developed giving opportunities to novel

I. Hemmilä; V. Laitala

2005-01-01

18

Shift reagent enhanced concurrent 23Na and 1H magnetic resonance spectroscopic studies of transcellular sodium distribution in the dog brain in vivo.  

PubMed

The intracellular to extracellular sodium distribution is one of the primary determinants of action potentials necessary for the electrical function of organs such as brain, heart and skeletal muscle. The ability of shift reagent enhanced 23Na MRS to directly measure the intracellular and extracellular sodium distribution in brain is controversial and centers on the relative contributions of bulk magnetic susceptibility and hyperfine interactions to the observed chemical shifts. In this study, infusion of dysprosium (III) triethylenetetraminehexacetate (Dy(TTHA)-3), resulted in a 23Na MRS spectrum of dog brain with two well resolved peaks at 9 and 0.4 ppm. The 9 ppm peak corresponded to the resonance seen in aspirated blood. After disruption of the blood brain barrier, the single peak at 0.4 ppm split into two peaks at 3 and 0 ppm. The ability of Dy(TTHA)-3 enhanced 23Na MRS to follow global changes in brain sodium distribution was tested during cardiac arrest. The expected rapid Na influx into the intracellular space produced a marked decrease in the 3 ppm signal and a parallel increase in the 0 ppm peak. This is consistent with the assignment of the 3 ppm peak as interstitial sodium and the 0 ppm peak as intracellular sodium. PMID:8371663

Eleff, S M; Mclennan, I J; Hart, G K; Maruki, Y; Traystman, R J; Koehler, R C

1993-07-01

19

23Na and 39K nuclear magnetic resonance studies of perfused rat hearts. Discrimination of intra- and extracellular ions using a shift reagent.  

PubMed Central

High-resolution 23Na and 39K nuclear magnetic resonance (NMR) spectra of perfused, beating rat hearts have been obtained in the absence and presence of the downfield shift reagent Dy(TTHA)3- in the perfusing medium. Evidence indicates that Dy(TTHA)3- enters essentially all extracellular spaces but does not enter intracellular spaces. It can thus be used to discriminate the resonances of the ions in these spaces. Experiments supporting this conclusion include interventions that inhibit the Na+/K+ pump such as the inclusion of ouabain in and the exclusion of K+ from the perfusing medium. In each of these experiments, a peak corresponding to intracellular sodium increased in intensity. In the latter experiment, the increase was reversed when the concentration of K+ in the perfusing medium was returned to normal. When the concentration of Ca2+ in the perfusing medium was also returned to normal, the previously quiescent heart resumed beating. In the beating heart where the Na+/K+ pump was not inhibited, the intensity of the intracellular Na+ resonance was less than 20% of that expected. Although the data are more sparse, the NMR visibility of the intracellular K+ signal appears to be no more than 20%.

Pike, M M; Frazer, J C; Dedrick, D F; Ingwall, J S; Allen, P D; Springer, C S; Smith, T W

1985-01-01

20

Laboratory Reagents  

SciTech Connect

Replaced by WMH-310, Section 4.17. This document outlined the basic methodology for preparing laboratory reagents used in the 222-S Standards Laboratory. Included were general guidelines for drying, weighing, transferring, dissolving, and diluting techniques common when preparing laboratory reagents and standards. Appendix A contained some of the reagents prepared by the laboratory.

CARLSON, D.D.

1999-10-08

21

XPS analyses of lanthanides phosphates  

NASA Astrophysics Data System (ADS)

XPS measurements were performed on lanthanide orthophosphates LnPO4 (Ln: La, Ce, Nd, Gd), and correlated with XRD and some EDS analyses. Single lanthanide phosphates LnPO4 and mixed lanthanide phosphates LnLn1-xPO, all crystallized in a monoclinic structure similar to the monazite mineral. Results were examined qualitatively and quantitatively, by considering the Ln 3d lines, P 2p line and O 1s line. Ionic sputtering does not induce significant broadening nor an additional shift of the lanthanide peaks and does not have an effect on their chemical environments, except in the case of cerium. However, sputtering seems to significantly reduce the intensity of the O 1s and P 2p peaks, while Auger peaks of carbon and oxygen atoms interfere, respectively, with the 3d line of gadolinium and neodymium. Those phenomena are all the more important when the Nd and Gd content is weak and must be taken into account for a quantitative analysis of the spectra. The quantitative analyses reveal the expected results for single monazites. On mixed phosphates, the measured phosphorous and oxygen amounts are generally more valid for non-sputtered sample surfaces than for sputtered surfaces, while the calculated relative amount of lanthanides [Ln]/[Ln?] are correct in all the cases. One of the important goals of this work was to have a satisfactory value for the atomic ratio La/Gd, and particularly in the case of (La,Ce)PO4 and (La,Gd)PO4, to obtain good agreement between the calculated lanthanides ratio Nd/Gd and ratios estimated from XRD and EDS measurements.

Glorieux, B.; Berjoan, R.; Matecki, M.; Kammouni, A.; Perarnau, D.

2007-01-01

22

Potency Reagents  

Center for Biologics Evaluation and Research (CBER)

Text Version... Reassortant; Reagents Available from CBER, NIBSC, TGA. WHO Recommended Strain for 2010-11: A/California/07/2009 like virus: ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

23

Selective recognition of americium by peptide-based reagents.  

PubMed

The separation of lanthanides from minor actinides such as americium and curium is an important step during the recycling process in the treatment of nuclear waste. However, the similar chemistry and ionic size of lanthanide and actinide ions make the separation challenging. Here, we report that a peptide-based reagent can selectively bind trivalent actinides over trivalent lanthanides by means of introducing soft-donor atoms into a peptide known as a lanthanide-binding tag (LBT). Fluorescence spectroscopy has been used to measure the dissociation constant of each metal/peptide complex. A 10-fold selectivity was obtained for Am(3+) over the similarly sized lanthanide cation, Nd(3+), when the asparagine on the fifth position of a LBT was mutated to a cysteine and further functionalized by a pyridine moiety. PMID:21819087

Özçubukçu, Salih; Mandal, Kalyanaswer; Wegner, Seraphine; Jensen, Mark P; He, Chuan

2011-08-05

24

Fracture-resistant lanthanide scintillators  

DOEpatents

Lanthanide halide alloys have recently enabled scintillating gamma ray spectrometers comparable to room temperature semiconductors (<3% FWHM energy resolutions at 662 keV). However brittle fracture of these materials upon cooling hinders the growth of large volume crystals. Efforts to improve the strength through non-lanthanide alloy substitution, while preserving scintillation, have been demonstrated. Isovalent alloys having nominal compositions of comprising Al, Ga, Sc, Y, and In dopants as well as aliovalent alloys comprising Ca, Sr, Zr, Hf, Zn, and Pb dopants were prepared. All of these alloys exhibit bright fluorescence under UV excitation, with varying shifts in the spectral peaks and intensities relative to pure CeBr.sub.3. Further, these alloys scintillate when coupled to a photomultiplier tube (PMT) and exposed to .sup.137Cs gamma rays.

Doty, F. Patrick (Livermore, CA)

2011-01-04

25

Novel oligomeric antennae for luminescent lanthanide cations  

SciTech Connect

Organic molecules have long been known to harvest light for the weakly absorbing lanthanide cations; however, in recent decades conjugated oligomers have presented promising photophysical properties. Lanthanide cations have desirable properties for applications that include sharp emission bands, long luminescence lifetimes and resistance to photobleaching. These properties arise partially from the shielded f-orbitals of the lanthanides, which interact weakly with their respective ligand(s). Lanthanides' long lifetimes enable spectral discrimination from background fluorescence through time-resolved measurements. In order to obtain their luminescence properties, lanthanide cations need to be sensitized through an appropriate antenna. Conjugated oligomers provide a platform as antennae with tunable energy of their donating levels. This is obtained by controlling the oligomer chain length (i.e. a more conjugated, longer sequence should have a lower energy of donating singlet and triplet states than a less conjugated, shorter sequence). We have designed and synthesized optically active oligofluorenyl ligands that coordinate and sensitize different luminescent lanthanide cations. Polyfluorenes are well known optically-active polymers. Fluorene derivatives, including its oligomers, often shift the emissive levels to lower energy making it an attractive donor. Fluorene possesses high functionality, allowing it to be incorporated into many applications, such as electroluminescent devices. In our systems, the fluorene backbone harvests the light and transfers the resulting energy to the lanthanide, bound by a coordinating moiety. Thus the energy of the donating level of the fluorene can be tuned, according to the size of the oligomer, to match the energy of the accepting levels of different lanthanides.

Oxley, D.S. (University of Pittsburgh); Copenhafer, J.E. (Arkema, Inc., King of Prussia, PA); Edenborn, H.M.; Meyer, T.Y. (University of Pittsburgh); Petoud, S. (University of Pittsburgh)

2007-01-01

26

Coordination of Lanthanide Acetates  

SciTech Connect

A study of the structures of hydrated and anhydrous lanthanide acetates by X-ray diffraction, infrared spectra, and absorption spectra demonstrates that there are three separate structures for hydrated lanthanide acetates and four structures for anhydrous acetates. This paper discusses the results of that study.

Karraker, D.G.

2001-08-29

27

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

28

Hyperfine interactions at lanthanide impurities in Fe  

NASA Astrophysics Data System (ADS)

The magnetic hyperfine field and electric-field gradient at isolated lanthanide impurities in an Fe host lattice are calculated from first principles, allowing a qualitative and quantitative understanding of an experimental data set collected over the past 40years . It is demonstrated that the common local density approximation leads to quantitatively and qualitatively wrong results, while the LDA+U method performs much better. In order to avoid pitfalls inherent to the LDA+U method, a combination of free ion calculations and “constrained density matrix” calculations is proposed and tested. Quantitative results for the exchange field and crystal field parameters are obtained ( Bexc=+420T , B04=-1000cm-1 , B06=-800cm-1 ), showing in particular how crystal field effects influence the hyperfine fields for the lightest and heaviest lanthanides. The hyperfine fields are shown to be dominated by the 4f orbital contribution, with small corrections due to the spin dipolar and Fermi contact fields. The latter is found to be constant for all lanthanides, a feature that is understood by a modified version of the well-known core polarization mechanism for 3d hyperfine fields. Spin dipolar fields and electric-field gradients have apart from a 4f contribution a surprisingly strong contribution due to the completely filled lanthanide 5p orbitals—the mechanism behind this is explained. The lanthanide 4f spin moment is found to couple antiparallel to the magnetization of the Fe lattice, in agreement with the model of Campbell and Brooks. There is strong evidence for a delocalization-localization transition that is shifted from Ce to at least Pr and maybe further up to Sm. This shift is interpreted in terms of the effective pressure felt by lanthanides in Fe. Implications for resolving ambiguities in the determination of delocalization in pure lanthanide metals under pressure are discussed. For the localized lanthanides, Yb is shown to be divalent in this host lattice, while all others are trivalent (including Eu). The temperature dependence of the hyperfine fields is discussed as well.

Torumba, D.; Vanhoof, V.; Rots, M.; Cottenier, S.

2006-07-01

29

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

30

The silicon lanthanide oxynitrides  

Microsoft Academic Search

A new group of materials called the silicon lanthanide oxynitrides has been prepared by the reaction between Si3N4 and several oxides of the lanthanide series (La2O3, Sm2O3, Dy2O3, Er2O3, and Yb2O3). These oxides formed compounds of the type Si3N4 · R2O3 and R4Si2O7N2 (R being lanthanide). In addition La2O3 and Yb2O3 formed the compounds 2Si3N4 · La2O3 and Yb2Si3O5N2, respectively.

R. R. Wills; R. W. Stewart; J. A. Cunningham; J. M. Wimmer

1976-01-01

31

Solvent extraction of lanthanides with N-m-nitrobenzoyl- and N-m-cyanobenzoyl-N-phenylhydroxylamine  

SciTech Connect

The solvent extraction of lanthanides (Ln) with N-m-nitrobenzoyl- and N-m-cyanobenzoyl-N-phenylhydroxylamine, was investigated. The representative lanthanides (Yb, Ho, Eu, Pr and La) were all found to extract with compounds as self-adducts of the form, LnL{sub 3}(HL){sub 3}, where L and HL denote the ligand anion and neutral ligand, respectively. The extraction constant and separation factor were compared with those of the N-p-octyloxy derivative bof N-benzoyl-N-phenylhydroxylamine previously reported. The correlation between extractability, mutual separability of lanthanides and acidity of the reagent were discussed. 14 refs., 4 figs., 3 tabs.

Inoue, Sadanobu [Kitami Inst. of Technology (Japan)

1995-03-01

32

Basics of Lanthanide Photophysics  

Microsoft Academic Search

\\u000a The fascination for lanthanide optical spectroscopy dates back to the 1880s when renowned scientists such as Sir William Crookes,\\u000a LeCoq de Boisbaudran, Eugène Demarçay or, later, Georges Urbain were using luminescence as an analytical tool to test the\\u000a purity of their crystallizations and to identify potential new elements. The richness and complexity of lanthanide optical\\u000a spectra are reflected in an

Jean-Claude G. Bünzli; Svetlana V. Eliseeva

33

Beyond samarium diiodide: vistas in reductive chemistry mediated by lanthanides(II).  

PubMed

Reactions proceeding through open-shell, single-electron pathways offer attractive alternative outcomes to those proceeding through closed-shell, two-electron mechanisms. In this context, samarium diiodide (SmI(2)) has emerged as one of the most important and convenient-to-use electron-transfer reagents available in the laboratory. Recently, significant progress has been made in the reductive chemistry of other divalent lanthanides which for many years had been considered too reactive to be of value to synthetic chemists. Herein, we illustrate how new samarium(II) complexes and nonclassical lanthanide(II) reagents are changing the landscape of modern reductive chemistry. PMID:22893612

Szostak, Michal; Procter, David J

2012-08-15

34

Thermolysis of lanthanide dithiocarbamate complexes  

NASA Astrophysics Data System (ADS)

Polycrystalline lanthanide sulfide materials were formed at low temperatures using a single-source precursor based on the lanthanide dithiocarbamate complex. The synthesis temperatures are generally lower than standard solid state preparations, avoid toxic sulfurizing gases and provide a convenient route to prepare lanthanide chalcogenide nanoparticles. Depending on the reaction conditions and oxophilicity of the lanthanide, the sulfide material was formed with oxidized products including oxysulfides, oxysulfates and the oxide.

Boncher, William L.; Regulacio, Michelle D.; Stoll, Sarah L.

2010-01-01

35

The Lanthanide Contraction Revisited  

PubMed Central

A complete, isostructural series of complexes with La-Lu (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 complexes from La-Lu (without Pm) 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 dependence 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 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.

2011-01-01

36

The 5d level positions of the trivalent lanthanides in inorganic compounds  

Microsoft Academic Search

The literature on 4fn?4fn?15d transitions of the trivalent lanthanides in inorganic compounds has been collected. From critically analyzing fd-excitation, absorption, reflection and df-emission spectra, values for the spectroscopic red shift of 5d levels and the stokes shift were determined. Data pertaining to 368 different lanthanide sites in over 300 different compounds (fluorides, chlorides, bromide, iodides, oxides, sulfides, selenides and oxy-nitrides)

P. Dorenbos

2000-01-01

37

Luminescent macrocyclic lanthanide complexes  

SciTech Connect

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

38

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

39

Spectrophotometric, potentiometric, and gravimetric determination of lanthanides with peri-dihydroxynaphthindenone  

SciTech Connect

Sensitive and reasonably selective methods are described for the spectrophotometric, potentiometric, and gravimetric determination of lanthanides using peri-dihydroxynaphthindenone as a novel chromogenic and precipitating reagent. The reagent forms a stable 1:2 (metal:reagent) type of complex with light lanthanides at pH 2-7 in 1:1 ethanol-water mixture. Low metal concentrations (<10 ..mu..g/mL) develop colored species (lambda/sub max/ 580 to 590 nm, epsilon/sub max/ (4-6) x 10/sup 4/ L mol/sup -1/ cm/sup -1/) which obey Beer's law. Quantitative precipitation of the complexes from metal solutions of concentrations > 100 ..mu..g/mL permits both gravimetric quantitation by igniting the precipitates to the metal oxides and potentiometric titration of the excess reagent. Results with an average recovery of 98% (standard deviation 0.7%) are obtainable for 0.1 ..mu..g to 200 mg of all light lanthanides. Many foreign ions naturally occurring or frequently associated with lanthanides do not interfere or can be tolerated.

Hassan, S.S.M.; Mahmoud, W.H.

1982-02-01

40

Tetrad effect in the adsorption of the lanthanides on zeolite Y.  

PubMed

The adsorption of the lanthanides (except for Pm) on the zeolite Y was investigated under various solution conditions of nitrate ion concentration ([NO(-)(3)]: 0.001-2 mol/dm(3)) and total lanthanide concentration (from 0.0001 to 0.001 mol/dm(3)). The solutions of the lanthanide nitrates were equilibrated with the zeolite samples at 296 K. The concentrations of lanthanides in the initial and equilibrium solutions were determined by means of spectrophotometrical method with Arsenazo III reagent and distribution constants K(d) of the lanthanides between aqueous and zeolite phases were calculated. The evident concave tetrad effect in the change of logK(d) values (nitrate concentrations 0.4-2 mol/dm(3)) within the lanthanide series was noticed and an attempt at its explanation through the comparison of covalence in LnO bonds existing in triple bond AlO(1/3Ln)Si triple bond species in the zeolite phase and in Ln(NO(3))(2+) complexes forming in the aqueous phase was presented. The weak convex tetrad effect for equilibrium nitrate concentrations 0.001-0.32 mol/dm(3), manifesting in the change of logK(d) values and in the alteration of logK (adsorption constants), is evidence of the complexation of the tripositive lanthanide ions by the oxygens originating both from water molecules and from the zeolite framework. PMID:17524414

G?adysz-P?aska, A; Majdan, M; Pikus, S; Lewandowski, W

2007-05-23

41

The Lanthanide Elements in Stellar and Laboratory Spectra  

NASA Astrophysics Data System (ADS)

The lanthanide elements (Z=57-71) are characterized by the filling of the 4f electronic subshell, which lies close in energy to the 5d and 6s subshells. As a result, the lanthanide spectra can be quite complicated in terms of the number of optical spectral lines, and in some cases their hyperfine structure and isotopic shifts are extremely large. These characteristics have great implications for astronomical investigations. We first review the stellar environments in which study of the lanthanides is important. These include the sun, chemically peculiar stars, and the oldest, most metal-deficient stars of the galaxy. We then touch on laboratory efforts directed at improving atomic data useful in analyzing astronomical spectra, in particular regarding wavelengths, line structure and line strength. Special emphasis is placed on the first three spectra of these elements and a reference list of laboratory analyses is provided.

Wahlgren, Glenn M.

42

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

43

Lanthanide alkylidene and imido complexes.  

PubMed

In stark contrast to the transition metals, examples of imido or alkylidene complexes of the lanthanides remain scarce. A recent literature survey reveals that only nine examples of lanthanide imido complexes have been reported, and the majority of these have arisen serendipitously. Concrete examples of species containing lanthanide-carbon multiple bonds are even more sparse. Recently, some rational approaches to the synthesis of lanthanide complexes containing Ln=X functionalities have been detailed (X = C, N). Additionally, a DFT (Density Functional Theory) study of a samarium imido complex has provided insight into the electronic and steric factors that may be necessary to support these unusual reactive groups. This Perspective reviews the work in this field and offers some suggestions to expand this potentially useful class of compounds. PMID:15303145

Giesbrecht, Garth R; Gordon, John C

2004-07-15

44

Separation of Actinides from Lanthanides.  

National Technical Information Service (NTIS)

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 ...

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

1988-01-01

45

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

46

Hybridization Assay by Time-Resolved Capillary Gel Electrophoresis with a Lanthanide Chelate  

Microsoft Academic Search

Capillary electrophoresis of crude biological samples with time-resolved fluorescence (TRF) detection enables elimination\\u000a of interference from organic fluorophores and from light scattering. Because the fluorescence lifetime of biological substances\\u000a and impurities overlaps the fluorescence lifetime of conventional labeling dyes, TRF detection with conventional organic labeling\\u000a dyes suffers from background fluorescence. In this work, we synthesized a luminescent lanthanide chelating reagent

Keiko Sumitomo; Takahisa Ito; Motoyasu Sasaki; Yoshinori Yamaguchi

2008-01-01

47

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

48

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

49

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

2012-08-06

50

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

51

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.

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

2011-01-01

52

Hypersensitive pseudoquadrupole transitions in lanthanides  

Microsoft Academic Search

It is pointed out that the absorption lines of the lanthanides that are peculiarly sensitive to changes in the ligands are consistent with the selection rules for quadrupole radiation within the 4f shell. A number of sources for this sensitivity are examined, and it is concluded that it owes its origin to the inhomogeneity of the dielectric. According to this

Chr. Klixbüll Jørgensen; B. R. Judd

1964-01-01

53

Theory of lanthanide crystal fields  

Microsoft Academic Search

Recent progress in understanding the origin of the lanthanide crystal field is summarized. The basic assumption of the crystal field parametrization is shown to be that the crystalline environment can be represented as a one-electron potential, and the consequences of removing this assumption are traced. It is further shown that overlap and covalency make the dominant contributions to the observed

D. J. Newman

1971-01-01

54

LANTHANIDE ENHANCE LUMINESCENCE (LEL) WITH ONE AND TWO PHOTON EXCITATION OF QUANTUM DYES LANTHANIDE (III) - MACROCYCLES  

EPA Science Inventory

Title: Lanthanide Enhance Luminescence (LEL) with one and two photon excitation of Quantum Dyes? Lanthanide(III)-Macrocycles Principal Author: Robert C. Leif, Newport Instruments Secondary Authors: Margie C. Becker, Phoenix Flow Systems Al Bromm, Virginia Commonw...

55

Lanthanide mixed ligand chelates for DNA profiling and latent fingerprint detection  

NASA Astrophysics Data System (ADS)

It is our aim to develop a universally applicable latent fingerprint detection method using lanthanide (rare-earth) complexes as a source of luminescence. Use of these lanthanide complexes offers advantages on several fronts, including benefits from large Stokes shifts, long luminescence lifetimes, narrow emissions, ability of sequential assembly of complexes, and chemical variability of the ligands. Proper exploitation of these advantages would lead to a latent fingerprint detection method superior to any currently available. These same characteristics also lend themselves to many of the problems associated with DNA processing in the forensic science context.

Menzel, E. R.; Allred, Clay

1997-02-01

56

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

57

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

58

Triazine-based condensing reagents.  

PubMed

The synthesis, properties, and application of condensing reagents derived from 1,3,5-triazines are described. The mechanism of activation of carboxylic function, structure of reactive intermediates, and mechanism of acylation of nucleophiles are presented. The synthetic versatility of mono- and bifunctional reagents for syntheses in solution, triazine-based immobilized reagents, chiral triazines for enantiodifferentiating syntheses, are discussed. The scope and limitation of the synthetic utility of triazine reagents in the preparation of heterocyclic compounds, amides, esters, oligopeptides-including large-scale syntheses and use in the combinatorial chemistry-is demonstrated. PMID:11074411

Kami?ski, Z J

2000-01-01

59

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

60

SYHERGISM OF TRTVALENT ACTINIDES AHD LANTHANIDES  

Microsoft Academic Search

The synergism of trivalent actinides and lanthanides has been reviewed oritically. Different systems Including ?-di-ketones and several other chelating agents with various neutral donors have been discussed. The thermodynamic parameters, effect of diluents, auto-synergism and synergism with eutectic mixtures have been discussed In the case of trivalent actinides and lanthanides. Also the mechanism of synergism and the various possible uses

J. N. Mathur

1983-01-01

61

Lanthanide cation-templated synthesis of rotaxanes.  

PubMed

The first lanthanide cation-templated synthesis of an interlocked structure is demonstrated through an interpenetrated assembly between a pyridine N-oxide threading component coordinating to a lanthanide cation complexed within a macrocycle. Stoppering of the pseudo-rotaxane assembly allows for preparation of the [2]rotaxane. PMID:23925587

Zapata, Fabiola; Blackburn, Octavia A; Langton, Matthew J; Faulkner, Stephen; Beer, Paul D

2013-09-25

62

US Veterinary Immune Reagents Network  

Technology Transfer Automated Retrieval System (TEKTRAN)

A major obstacle to advances in veterinary immunology and disease control is the lack of sufficient immunological reagents specific for ruminants, swine, poultry, equine, and aquaculture species. Sets of reagents, i.e. monoclonal (mAb) and polyclonal antibodies (Ab), that can identify the major leu...

63

Helical Lanthanide(III) Complexes with Chiral Nonaaza Macrocycle  

PubMed Central

The chiral nonaazamacrocyclic amine L, which is a reduction product of the 3+3 Schiff base macrocycle, wraps around the lanthanide(III) ions to form enantiopure helical complexes. These Ce(III), Pr(III), Nd(III), Eu(III), Gd(III), Tb(III), Er(III), Yb(III) and Lu(III) complexes have been isolated in enantiopure form and have been characterized by spectroscopic methods. X-ray crystal structures of the Ln(III) complexes with L show that the thermodynamic product of the complexation of the RRRRRR-isomer of the macrocycle is the (M)-helical complex in the case of Ce(III), Pr(III), Nd(III) and Eu(III). In contrast, the (P)-helical complex is the thermodynamic product in the case of Yb(III) and Lu(III). The NMR and CD spectra show that the (M)-helicity for the kinetic complexation product of the RRRRRR-isomer of the macrocycle is preferred for all investigated lanthanide(III) ions, while the preferred helicity of the thermodynamic product is (M) for the early lanthanide(III) ions and (P) for the late lanthanide(III) ions. In the case of the late lanthanide(III) ions, a slow inversion of helicity between the kinetic (M)-helical product and the thermodynamic (P)-helical product is observed in solution. For Er(III), Yb(III) and Lu(III) both forms have been isolated in pure form and characterized by NMR and CD. The analysis of 2D NMR spectra of the Lu(III) complex reveals the NOE correlations that prove that the helical structure is retained in solution. The NMR spectra also reveal large isotopic effect on the 1H NMR shifts of paramagnetic Ln(III) complexes, related to NH/ND exchange. Photophysical measurements show that LRRRRRR appears to favour an efficient 3??*-to-Ln energy transfer process taking place for Eu(III) and Tb(III), but these Eu(III)- and Tb(III)-containing complexes with LRRRRRR lead to small luminescent quantum yields due to an incomplete intersystem crossing (isc) transfer, a weak efficiency of the luminescence sensitization by the ligand, and/or efficient non-radiative deactivation processes. Circularly polarized luminescence on the MeOH solutions of Eu(III) and Tb(III) complexes confirms the presence of stable chiral emitting species and the observation of almost perfect mirror-image CPL spectra for these compounds with both enantiomeric forms of L.

Gregolinski, Janusz; Starynowicz, Przemyslaw; Hua, KimNgan T.; Lunkley, Jamie L.

2009-01-01

64

In vivo sodium chemical shift imaging.  

PubMed

The shift reagents thulium(III) 1,4,7,10-tetraazacyclododecane N,N',N",N"'tetramethylenephosphonate (TmDOTP5-), and dysprosium(III)triethylenetetramine-hexaacetate (DyTTHA3-) are compared in this work for their uses in sodium chemical shift imaging (NaCSI). In a series of experiments using phantoms we evaluated the relative contributions of bulk magnetic susceptibility (BMS) effects and hyperfine shifts to the induced 23Na chemical shift for these two shift reagents. The ratios of BMS effects to hyperfine shifts suggest that TmDOTP5- should be a more effective shift reagent than DyTTHA3- for 23Na NMR spectroscopy as well as NaCSI. The dependence on pH and free Ca2+ concentration of the 23Na NMR frequency shift induced by TmDOTP5- was evaluated. It was found that TmDOTP5- produces good spectral resolution under physiologic conditions. Examples presented from in vivo NaCSI experiments using TmDOTP5- to study diffusion in the posterior chamber of the rabbit eye and to monitor the rate of clearance of aqueous fluid from the anterior chamber demonstrate the effectiveness of this new shift reagent and of the NaCSI technique for in vivo studies. PMID:1310341

Kohler, S J; Kolodny, N H; Celi, A C; Burr, T A; Weinberg, D; D'Amico, D J; Gragoudas, E S

1992-01-01

65

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

66

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

67

21 CFR 866.3280 - Francisella tularensis serological reagents.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Francisella tularensis serological reagents. 866.3280...Reagents § 866.3280 Francisella tularensis serological reagents. (a) Identification. Francisella tularensis serological reagents are...

2009-04-01

68

21 CFR 866.3280 - Francisella tularensis serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Francisella tularensis serological reagents. 866.3280...Reagents § 866.3280 Francisella tularensis serological reagents. (a) Identification. Francisella tularensis serological reagents are...

2010-04-01

69

Role of lanthanides in optical materials.  

National Technical Information Service (NTIS)

A survey is presented of the use of the lanthanides as chemical components in transmitting optical materials and as activators in materials for luminescent, electro-optic, magneto-optic, and various photosensitive applications.

M. J. Weber

1995-01-01

70

The role of lanthanides in optical materials  

SciTech Connect

A survey is presented of the use of the lanthanides as chemical components in transmitting optical materials and as activators in materials for luminescent, electro-optic, magneto-optic, and various photosensitive applications.

Weber, M.J.

1995-05-01

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

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

2012-09-04

73

Bis(Phthalocyaninato) Lanthanide Sandwich Compounds Exhibiting Mixed Valence Ligands.  

National Technical Information Service (NTIS)

Bis(phthalocyaninato) lanthanide sandwich compounds have been synthesized for ytterbium and thulium. Low temperature magnetic susceptibility data suggest a strong antiferromagnetic interaction between the lanthanide f-electrons and the phythalocyaninato l...

K. D. Kepler K. L. Trojan M. L. Kirk W. E. Hatfield

1990-01-01

74

Nonaqueous method for dissolving lanthanide and actinide metals  

DOEpatents

Lanthanide and actinide beta-diketonate complex molecular compounds are produced by reacting a beta-diketone compound with a lanthanide or actinide element in the elemental metallic state in a mixture of carbon tetrachloride and methanol.

Crisler, L.R.

1975-11-11

75

Method Bacterial Endospore Quantification Using Lanthanide Dipicolinate Luminescence.  

National Technical Information Service (NTIS)

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 concen...

A. Ponce J. P. Kirby K. J. Venkateswaran

2007-01-01

76

Adsorption of lanthanides on mordenite from nitrate medium  

Microsoft Academic Search

The adsorption of lanthanides (except for Pm) on mordenite was investigated under various solution conditions of nitrate ion concentrations ([NO?3]: 0.001–2 mol\\/dm3) and total lanthanide concentrations (0.0005 mol\\/dm3). Solutions of lanthanide nitrates were equilibrated with zeolite samples at 296 K. A concave tetrad effect was evident in the change of logKd values within the lanthanide series and an explanation by

Agnieszka G?adysz-P?aska; Marek Majdan; Stanis?aw Pikus

2008-01-01

77

Determination of lanthanides in synthetic standards by reversed-phase high-performance liquid chromatography with the aid of a weighted least-squares regression model estimation of method sensitivities and detection limits.  

PubMed

A reversed-phase liquid chromatography method was used for determining lanthanides in synthetic standards. The separation of lanthanide group was achieved in less than 15 min using a linear gradient program of alpha-hydroxyisobutyricacid eluent from 0.05 to 0.5 M (pH 3.8) with a UV-Vis detection system at 658 nm. A post-column reagent of Arsenazo III was employed for improving the sensitivity and selectivity of the method as well as for lowering the limits of detection (LODs). Linear calibration curves for all lanthanides were constructed using an ordinary least-squares (OLS) regression as well as a weighted least-squares (WLS) regression model for taking into account the heteroscedastic errors. The WLS model was successfully used for a better estimation of the sensitivities and the LODs of the RP-HPLC method than the conventional OLS model. The lanthanide sensitivity obtained from the slope of each calibration curve seems to be better for a lanthanide with an odd-atomic number compared to its neighboring element with an even-atomic number, as if nature is helping us to quantify the concentrations of the less abundant lanthanides. This observation was also confirmed when the LODs computed for all lanthanides were examined. The LODs observed for all lanthanides depicted a clear systematic "zigzag" pattern. This is actually the first time that the lanthanide detection limits determined by a HPLC method are shown to mimic the zigzag patterns for the concentration data in geological and cosmological materials. Such a "zigzag" pattern should be used as a standard criterion for evaluating the quality of detection limit data. PMID:12830890

Santoyo, E; Verma, Surendra P

2003-05-16

78

Systematic behaviour in trivalent lanthanide charge transfer energies  

Microsoft Academic Search

Information on the energy that is needed to transfer an electron from the valence band of an inorganic compound to a trivalent lanthanide impurity is presented. The energy is a measure of the location of the ground state of the divalent lanthanide relative to the top of the valence band. A variation with type of lanthanide is found that is

P. Dorenbos

2003-01-01

79

Extraction of actinide and lanthanide complexonates in potassium carbonate-poly(ethylene glycol)-water two-phase aqueous system  

SciTech Connect

An extraction system based on poly(ethylene glycol) for preconcentrating, isolating and separating actinides, is proposed. The extraction of actinides and lanthanides in a potassium carbonate-poly(ethylene glycol)-water two-phase aqueous system in the presence of various complexones was studied. Trivalent actinides are quantitatively extracted by poly(ethylene glycol) from potassium carbonate solutions in a system with Xylenol Orange and alizarin complexone. Under these conditions, uranium (VI) and plutonium (IV) are extracted inappreciably into a phase enriched with poly(ethylene glycol), so that they can be separated from trivalent actinides with a separation factor of 10/sup 2/-10/sup 3/. To separate actinides and lanthanides, two complexones were introduced into the system, one of which served as an extractant, and the other as a masking reagent. The best results were obtained for a mixture of Xylenol Orange and hydroxyethylidenediphosphonic acid. The separation coefficients of americium and europium are 4.5-5.6.

Molochnikova, N.P.; Shkinev, V.M.; Spivakov, B.Ya.; Zolotov, Yu.A.; Myasoedov, B.F.

1988-09-01

80

Selective Separation of Trivalent Actinides from Lanthanides by Aqueous Processing with Introduction of Soft Donor Atoms  

SciTech Connect

Implementation of a closed loop nuclear fuel cycle requires the utilization of Pu-containing MOX fuels with the important side effect of increased production of the transplutonium actinides, most importantly isotopes of Am and Cm. Because the presence of these isotopes significantly impacts the long-term radiotoxicity of high level waste, it is important that effective methods for their isolation and/or transmutation be developed. Furthermore, since transmutation is most efficiently done in the absence of lanthanide fission products (high yield species with large thermal neutron absorption cross sections) it is important to have efficient procedures for the mutual separation of Am and Cm from the lanthanides. The chemistries of these elements are nearly identical, differing only in the slightly stronger strength of interaction of trivalent actinides with ligand donor atoms softer than O (N, Cl-, S). Research being conducted around the world has led to the development of new reagents and processes with considerable potential for this task. However, pilot scale testing of these reagents and processes has demonstrated the susceptibility of the new classes of reagents to radiolytic and hydrolytic degradation. In this project, separations of trivalent actinides from fission product lanthanides have been investigated in studies of 1) the extraction and chemical stability properties of a class of soft-donor extractants that are adapted from water-soluble analogs, 2) the application of water soluble soft-donor complexing agents in tandem with conventional extractant molecules emphasizing fundamental studies of the TALSPEAK Process. This research was conducted principally in radiochemistry laboratories at Washington State University. Collaborators at the Radiological Processing Laboratory (RPL) at the Pacific Northwest National Laboratory (PNNL) have contributed their unique facilities and capabilities, and have supported student internships at PNNL to broaden their academic experience. New information has been developed to qualify the extraction potential of a class of pyridine-functionalized tetraaza complexants indicating potential single contact Am-Nd separation factors of about 40. The methodology developed for characterization will find further application in our continuing efforts to synthesize and characterize new reagents for this separation. Significant new insights into the performance envelope and supporting information on the TALSPEAK process has also been developed.

Kenneth L. Nash

2009-09-22

81

[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

82

Radiometallacarboranes as tumor imaging reagents  

Microsoft Academic Search

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

M. Frederick Hawthorne; Aravamuthan Varadarajan; Carolyn B. Knobler; Sarmistha Chakrabarti; Raymond J. Paxton; Barbara G. Beatty; Frederick L. Curtis

1990-01-01

83

Sensing lanthanide metal content in biological tissues with magnetic resonance spectroscopy.  

PubMed

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 ³10 mM for Tm(III) Eu(III), and Yb(III), and ³3 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

2013-10-11

84

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

85

Recovery system containing lanthanide-crosslinked polymers  

SciTech Connect

A recovery system is described comprising: (a) a subterranean formation; (b) a well bore penetrating at least a portion of the subterranean formation; and (c) a composition capable of forming a gel present in at least a portion of the well bore, wherein the composition comprises: (i) a crosslinkable polymer (CP) selected from the group consisting of heteropolysaccharides obtained by the fermentation of starch-derived sugar, ammonium salts, and alkali metal salts; (ii) a lanthanide; and (iii) an ingredient selected from the group consisting of gel breakers, sequestering agents, proppants for use in hydraulically fracturing, particulate agents for forming a gravel pack, and base precursors selected from the group consisting of ammonium slats, urea, thiourea, and mixtures of these. A second recovery system is described in which the gel composition comprises: (i) a CP selected from the group consisting of acrylic acid-acrylamide copolymers, acrylic acid-methacrylamide copolymers, polyacrylamides, polymethacrylamides, partially hydrolyzed polyacrylamides, partially hydrolyzed polymethacrylamides, polyvinyl alcohol, polyvinyl acetate, polyvinyl pyrrolidone, polyalkyleneoxides, lignosulfonates, ammonium salts, alkali metal salts, and alkaline earth salts of lignosulfonates; and (ii) a crosslinking agent selected from the group consisting of lanthanides, sequestered lanthanides, and mixtures thereof. A third system is described in which the gel composition comprises: (i) a CP, hydroxyethylcellulose; and (ii) a crosslinking agent selected from the group consisting of lanthanides, sequestered lanthanides, and mixtures thereof. A fourth system is described in which the gel composition comprises: (i) a CP selected from the group consisting of polyvinyl alcohol, polyvinyl acetate, polyvinyl pyrrolidone, polyalkyleneoxides, lignosulfonates, ammonium salts, alkali metal salts, and alkaline earth salts of lignosulfonates; and (ii) a lanthanide.

Dovan, H.T.; Hutchins, R.D.

1993-07-13

86

Validation of a lanthanide tag for the analysis of protein dynamics by paramagnetic NMR spectroscopy.  

PubMed

Paramagnetic lanthanide tags potentially can enhance the effects of microsecond to millisecond dynamics in proteins on NMR signals and provide structural information on lowly populated states encoded in the pseudocontact shifts. We have investigated the microsecond to millisecond mobility of a two-point attached lanthanide tag, CLaNP-5, using paramagnetic (1)H CPMG relaxation dispersion methods. CLaNP-5 loaded with Lu(3+), Yb(3+), or Tm(3+) was attached to three sites on the surface of two proteins, pseudoazurin and cytochrome c. The paramagnetic center causes large relaxation dispersion effects for two attachment sites, suggesting that local dynamics of the protein at the attachment site causes mobility of the paramagnetic center. At one site the relaxation dispersions are small and limited to the immediate environment of the tag. It is concluded that paramagnetic relaxation dispersion could represent a sensitive method to probe protein dynamics. However, the selection of a rigid attachment site is of critical importance. PMID:20586489

Hass, Mathias A S; Keizers, Peter H J; Blok, Anneloes; Hiruma, Yoshitaka; Ubbink, Marcellus

2010-07-28

87

New phosphonate reagents for aldehyde homologation  

Technology Transfer Automated Retrieval System (TEKTRAN)

New phosphonate reagents were developed for the two-carbon homologation of aldehydes to unbranched- or methyl-branched unsaturated aldehydes. The phosphonate reagents, diethyl methylformyl-2-phosphonate dimethylhydrazone and diethyl ethylformyl-2-phosphonate dimethylhydrazone, contained a protected...

88

Nomenclature for Monoclonal Blood Grouping Reagents  

Center for Biologics Evaluation and Research (CBER)

Text VersionPage 1. Nomenclature for Monoclonal Blood Grouping Reagents (9/28/92) ... Subject: Nomenclature for Monoclonal Blood Grouping Reagents ... More results from www.fda.gov/downloads/biologicsbloodvaccines/guidancecomplianceregulatoryinformation

89

21 CFR 866.4100 - Complement reagent.  

Code of Federal Regulations, 2013 CFR

... FOOD 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)...

2013-04-01

90

Monodentate vs bidentate binding of lanthanide cations to PO{sub 2}{sup -} in bacteriorhodopsin  

SciTech Connect

The frequency difference between the symmetric and antisymmetric stretching vibration of PO{sub 2}{sup +} in phosphatidylglycerol phosphate (PGP) is used to differentiate between monodentate and bidentate binding of these groups to metal cations in the membrane of bacteriorhodopsin (bR) and phosphatidylglycerol phosphate. The binding of Ca{sup 2}{sup +} to PGP is found to have a frequency difference corresponding to monodentate binding. The symmetric and antisymmetric PO{sub 2}{sup +} bands in bR show similar frequency shifts upon Ca{sup 2}{sup +} binding, which is independent of pH. This suggests that Ca{sup 2}{sup +} has a monodentate type binding with the PO{sub 2}{sup -} in bR. In contrast, the PO{sub 2}{sup -} symmetric and antisymmetric frequencies of PGP complexes with trivalent lanthanide cations with higher charge density (Ho{sup 3}{sup +} and Dy{sup 3}{sup +}) are observed to have smaller separations and to increase their separation with increasing pH toward the value observed for Ca{sup 2}{sup +} binding. Lanthanide cations (Ho{sup 3}{sup +}, Dy{sup 3}{sup +}, Eu{sup 3}{sup +}, Nd{sup 3}{sup +}, and La{sup 3}{sup +}) binding in bR and pH 4 show small frequency separations that are observed to have similar frequency shifts with pH, the magnitude to which is dependent on the cation. It is proposed that at low pH the lanthanide cations with higher charge density have bidentate binding to bR, while at high pH, complexation with the OH{sup -} competes with one of the oxygens of the PO{sub 2}{sup -} for the binding of the lanthanide ion thus changing the bidentate to monodentate type binding. 25 refs., 5 figs.

Griffiths, J.A.; Masciangioli, T.M.; El-Sayed, M.A. [Georgia Inst. of Technology, Atlanta, GA (United States); Roselli, C. [CEA Saclay, Gif-Sur-Yvette (France)

1996-04-18

91

21 CFR 866.3370 - Mycobacterium tuberculosis immunofluorescent reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Mycobacterium tuberculosis immunofluorescent reagents...Reagents § 866.3370 Mycobacterium tuberculosis immunofluorescent reagents...a) Identification. Mycobacterium tuberculosis...

2010-04-01

92

21 CFR 866.3370 - Mycobacterium tuberculosis immunofluorescent reagents.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Mycobacterium tuberculosis immunofluorescent reagents...Reagents § 866.3370 Mycobacterium tuberculosis immunofluorescent reagents...a) Identification. Mycobacterium tuberculosis...

2009-04-01

93

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

94

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

95

Homogeneous Catalysis Using Lanthanide Amidinates and Guanidinates  

NASA Astrophysics Data System (ADS)

For decades, the organometallic chemistry of the rare earth elements was largely dominated by the cyclopentadienyl ligand and its ring-substituted derivatives. A hot topic in current organolanthanide chemistry is the search for alternative ligand sets which are able to satisfy the coordination requirements of the large lanthanide cations. Among the most successful approaches in this field is the use of amidinate ligands of the general type [RC(NR ' )2]- (R = H, alkyl, aryl; R ' = alkyl, cycloalkyl, aryl, SiMe3) which can be regarded as steric cyclopentadienyl equivalents. Closely related are the guanidinate anions of the general type [R2NC(NR ' )2]- (R = alkyl, SiMe3; R ' = alkyl, cycloalkyl, aryl, SiMe3). Two amidinate or guanidinate ligands can coordinate to a lanthanide ion to form a metallocene-like coordination environment which allows the isolation and characterization of stable though very reactive amide, alkyl, and hydride species. Mono- and trisubstituted lanthanide amidinate and guanidinate complexes are also readily available. Various rare earth amidinates and guanidinates have turned out to be very efficient homogeneous catalysts, for example, for ring-opening polymerization reactions. This article covers the success story of lanthanide amidinates and guanidinates and their transition from mere laboratory curiosities to efficient homogeneous catalysts.

Edelmann, Frank T.

96

Ionic Interactions in Volatile Lanthanide Chelates  

Microsoft Academic Search

In order to allow estimation of the electrostatic and dipolar contributions to the cohesive forces in volatile lanthanide ?-diketonates, these compounds are considered to be purely ionic. The relevant lattice sums can then be computed directly and underestimation of the ionic contributions is avoided. Even without considering the effect of shielding by bulky substituents, the calculations, based on crystallographic results,

J. C. A. Boeyens

1971-01-01

97

Luminogenic "clickable" lanthanide complexes for protein labeling.  

PubMed

Development of lanthanide-based luminescent "switch-on" systems via azide-alkyne [3+2] cycloaddition is described. We used these for non-specific protein labeling and as tags for specific and selective activity-based protein labeling. PMID:23998183

Candelon, Nicolas; H?dade, Niculina D; Matache, Mihaela; Canet, Jean-Louis; Cisnetti, Federico; Funeriu, Daniel P; Nauton, Lionel; Gautier, Arnaud

2013-08-30

98

From antenna to assay: lessons learned in lanthanide luminescence.  

PubMed

Ligand-sensitized, luminescent lanthanide(III) complexes are of considerable importance because their unique photophysical properties (microsecond to millisecond lifetimes, characteristic and narrow emission bands, and large Stokes shifts) make them well suited as labels in fluorescence-based bioassays. The long-lived emission of lanthanide(III) cations can be temporally resolved from scattered light and background fluorescence to vastly enhance measurement sensitivity. One challenge in this field is the design of sensitizing ligands that provide highly emissive complexes with sufficient stability and aqueous solubility 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. Our approach involves developing high-stability octadentate Tb(III) and Eu(III) complexes that rely on all-oxygen donor atoms and using multichromophore chelates to increase molar absorptivity; earlier examples utilized a single pendant chromophore (that is, a single "antenna"). Ligands based on 2-hydroxyisophthalamide (IAM) provide exceptionally emissive Tb(III) complexes with quantum yield values up to approximately 60% that are stable at the nanomolar concentrations required for commercial assays. Through synthetic modification of the IAM chromophore and 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 used the 1-hydroxypyridin-2-one (1,2-HOPO) chelate to create remarkable ligands that combine excellent photophysical properties and exceptional aqueous stabilities. A more complete understanding of this chromophore has been achieved by combining low-temperature phosphorescence measurements with the same TD-DFT approach used with the IAM system. Eu(III) complexes with strong CPL activity have also been obtained with chiral 1,2-HOPO ligands. We have also undertaken kinetic analysis of radiative and nonradiative decay pathways for a series of Eu(III) complexes; the importance of the metal ion symmetry on the ensuing photophysical properties is clear. Lastly, we describe a Tb(III)-IAM compound--now carried through to commercial availability--that offers improved performance in the common HTRF platform and has the potential to vastly improve sensitivity. PMID:19323456

Moore, Evan G; Samuel, Amanda P S; Raymond, Kenneth N

2009-04-21

99

Effective core potential studies of lanthanide complexes  

SciTech Connect

A recently developed compact effective core potential (ECP) scheme for lanthanides [T. R. Cundari and W. J. Stevens, J. Chem. Phys. {bold 98}, 5555 (1993)] is applied to molecular species---the lanthanide trihalides (LnX{sub 3}, Ln=Ce to Lu; X=F, Cl, Br, I). This research is the first ECP study of lanthanide trihalides in which 4{ital f} electrons are explicitly included in the lanthanide valence space. The high-spin 4{ital f}{sup {ital n}} configuration of Ln(III) is described using multiconfiguration (MC) and unrestricted Hartree-Fock (UHF) wave functions. Both methods give excellent agreement with experiment for Ln--X bond lengths, although UHF is faster with no evidence of extensive spin contamination. There is no loss of accuracy from early to late members of the lanthanide series and from the lightest to heaviest halogen for the MC calculations. The root-mean-square difference between MC/ECP Ln--X bond lengths and those estimated from gas-phase experiments is only 0.05 A ({approx}2%). The UHF calculations on LnF{sub 3} yield only three nonplanar minima (CeF{sub 3}, PrF{sub 3}, and PmF{sub 3}). For the three complexes with pyramidal minima, the planar transition states are very close in energy ({Delta}{ital E}{sub UHF}{lt}100 cm{sup {minus}1}), suggesting these complexes will probably be fluxional at ambient conditions. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Cundari, T.R.; Sommerer, S.O.; Strohecker, L.A.; Tippett, L. [Department of Chemistry, The University of Memphis, Memphis, Tennessee 38152 (United States)

1995-10-22

100

21 CFR 866.3035 - Arizona spp. serological reagents.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Arizona spp. serological reagents. 866.3035... Serological Reagents § 866.3035 Arizona spp. serological reagents. (a) Identification. Arizona spp. serological reagents are...

2013-04-01

101

21 CFR 866.3330 - Influenza virus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Influenza virus serological reagents. 866...Serological Reagents § 866.3330 Influenza virus serological reagents. (a) Identification. Influenza virus serological reagents are...

2010-04-01

102

21 CFR 866.3510 - Rubella virus serological reagents.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Rubella virus serological reagents. 866.3510 Section...Serological Reagents § 866.3510 Rubella virus serological reagents. (a) Identification. Rubella virus serological reagents are devices...

2013-04-01

103

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

104

21 CFR 866.3550 - Salmonella spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...2012-04-01 2012-04-01 false Salmonella spp. serological reagents. 866...Serological Reagents § 866.3550 Salmonella spp. serological reagents. (a) Identification. Salmonella spp. serological reagents...

2012-04-01

105

21 CFR 866.3340 - Klebsiella spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Klebsiella spp. serological reagents. 866...Serological Reagents § 866.3340 Klebsiella spp. serological reagents. (a) Identification. Klebsiella spp. serological reagents...

2009-04-01

106

21 CFR 866.3340 - Klebsiella spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Klebsiella spp. serological reagents. 866...Serological Reagents § 866.3340 Klebsiella spp. serological reagents. (a) Identification. Klebsiella spp. serological reagents...

2010-04-01

107

21 CFR 864.8950 - Russell viper venom reagent.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Russell viper venom reagent. 864.8950 Section 864...Hematology Reagents § 864.8950 Russell viper venom reagent. (a) Identification. Russell viper venom reagent is a device used to...

2013-04-01

108

21 CFR 864.8950 - Russell viper venom reagent.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Russell viper venom reagent. 864.8950 Section 864...Hematology Reagents § 864.8950 Russell viper venom reagent. (a) Identification. Russell viper venom reagent is a device used to...

2010-04-01

109

21 CFR 864.8950 - Russell viper venom reagent.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Russell viper venom reagent. 864.8950 Section 864...Hematology Reagents § 864.8950 Russell viper venom reagent. (a) Identification. Russell viper venom reagent is a device used to...

2009-04-01

110

21 CFR 866.3020 - Adenovirus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Adenovirus serological reagents. 866.3020...Serological Reagents § 866.3020 Adenovirus serological reagents. (a) Identification. Adenovirus serological reagents are devices...

2009-04-01

111

21 CFR 866.3020 - Adenovirus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Adenovirus serological reagents. 866.3020...Serological Reagents § 866.3020 Adenovirus serological reagents. (a) Identification. Adenovirus serological reagents are devices...

2010-04-01

112

21 CFR 866.3200 - Echinococcus spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Echinococcus spp. serological reagents. 866...Serological Reagents § 866.3200 Echinococcus spp. serological reagents. (a) Identification. Echinococcus spp. serological reagents...

2009-04-01

113

21 CFR 866.3200 - Echinococcus spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Echinococcus spp. serological reagents. 866...Serological Reagents § 866.3200 Echinococcus spp. serological reagents. (a) Identification. Echinococcus spp. serological reagents...

2010-04-01

114

21 CFR 866.3120 - Chlamydia serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Chlamydia serological reagents. 866.3120...Serological Reagents § 866.3120 Chlamydia serological reagents. (a) Identification. Chlamydia serological reagents are devices...

2010-04-01

115

21 CFR 866.3120 - Chlamydia serological reagents.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Chlamydia serological reagents. 866.3120...Serological Reagents § 866.3120 Chlamydia serological reagents. (a) Identification. Chlamydia serological reagents are devices...

2009-04-01

116

21 CFR 866.3145 - Coxsackievirus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Coxsackievirus serological reagents. 866.3145...Serological Reagents § 866.3145 Coxsackievirus serological reagents. (a) Identification. Coxsackievirus serological reagents are...

2010-04-01

117

21 CFR 866.3145 - Coxsackievirus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Coxsackievirus serological reagents. 866.3145...Serological Reagents § 866.3145 Coxsackievirus serological reagents. (a) Identification. Coxsackievirus serological reagents are...

2009-04-01

118

21 CFR 866.3780 - Toxoplasma gondii serological reagents.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Toxoplasma gondii serological reagents. 866...Serological Reagents § 866.3780 Toxoplasma gondii serological reagents. (a) Identification. Toxoplasma gondii serological reagents...

2009-04-01

119

21 CFR 866.3780 - Toxoplasma gondii serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Toxoplasma gondii serological reagents. 866...Serological Reagents § 866.3780 Toxoplasma gondii serological reagents. (a) Identification. Toxoplasma gondii serological reagents...

2010-04-01

120

21 CFR 866.3940 - West Nile virus serological reagents.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false West Nile virus serological reagents. 866...Serological Reagents § 866.3940 West Nile virus serological reagents. (a) Identification. West Nile virus serological reagents...

2013-04-01

121

21 CFR 866.3940 - West Nile virus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false West Nile virus serological reagents. 866...Serological Reagents § 866.3940 West Nile virus serological reagents. (a) Identification. West Nile virus serological reagents...

2010-04-01

122

21 CFR 866.3940 - West Nile virus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false West Nile virus serological reagents. 866...Serological Reagents § 866.3940 West Nile virus serological reagents. (a) Identification. West Nile virus serological reagents...

2009-04-01

123

21 CFR 866.3355 - Listeria spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Listeria spp. serological reagents. 866...Serological Reagents § 866.3355 Listeria spp. serological reagents. (a) Identification. Listeria spp. serological reagents are...

2009-04-01

124

21 CFR 866.3355 - Listeria spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Listeria spp. serological reagents. 866...Serological Reagents § 866.3355 Listeria spp. serological reagents. (a) Identification. Listeria spp. serological reagents are...

2010-04-01

125

21 CFR 864.4010 - General purpose reagent.  

Code of Federal Regulations, 2013 CFR

...cytological preservatives, decalcifying reagents, fixative and adhesives, tissue processing reagents, isotonic solutions and pH buffers. Reagents used in tests for more than one individual chemical substance or ligand are general purpose reagents...

2013-04-01

126

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

127

Chapter 10 - Lanthanide-loaded paramagnetic liposomes as switchable magnetically oriented nanovesicles.  

PubMed

Magnetically oriented liposomes can be prepared by exposing unilamellar spherical systems loaded with paramagnetic lanthanide(III) complexes to hyperosmotic stress. The resulting nonspherical, lens-shaped, nanoparticles can orient within a static magnetic field, depending on the magnetic properties of their membrane bilayer. The orientation of the vesicles can be easily determined by measuring the paramagnetic contribution to the (1)H chemical shift of the intraliposomal water proton resonance. As the latter shift is dominated by the bulk magnetic susceptibility contribution, its sign (negative or positive) reports about the preferred orientation adopted by the nanovesicles. The alignment within the field depends upon the magnetic susceptibility anisotropy of the liposome membrane, Delta(chi)(LIPO). When Delta(chi)(LIPO) has a negative value (e.g., for nonspherical liposomes made of conventional phospholipids), the nanoparticles align with their long axis parallel to the field, whereas when Delta(chi)(LIPO)>0 the vesicles flip by 90 degrees . The sign of the chemical shift of the intraliposomal water resonance is positive in the former case and negative in the latter, respectively. The liposome orientation can be switched by incorporating in the liposome bilayer suitable amphiphilic paramagnetic lanthanide(III) complexes. The sign of Delta(chi)(LIPO), and consequently the magnetic alignment, will correspond to the sign of the magnetic susceptibility anisotropy of the metal complex. The magnetic susceptibility anisotropy is dependent on both the electronic configuration of the lanthanide ion and the structural characteristics of the amphiphilic complex incorporated in the liposome membrane. The magnetic orientation of such vesicles is maintained in vivo, thus opening promising perspectives for the application of nonspherical liposomes in medical imaging. PMID:19903556

Aime, Silvio; Castelli, Daniela Delli; Terreno, Enzo

2009-01-01

128

Partial Molar Volumes for Lanthanide Sesquioxides in Sodium Silicate Melts  

NASA Astrophysics Data System (ADS)

Lanthanides are of great interest in igneous petrology as trace indicators of magmatic processes that control the origin and evolution of igneous rocks. A key to the petrogenetic modelling of magmatic processes and to determine the phase diagrams of lanthanide host phases is the accurate determination of the physico-chemical and thermodynamic properties of lanthanide-containing materials, such as the volumetric properties of lanthanide-bearing silicate melts. Therefore, we have undertaken to provide a new reliable volumetric data set for lanthanide-bearing silicate melts which allows the available models in the literature to be extended to lanthanide-bearing melts. For this purpose, the densities of various lanthanide-bearing silicate melts distributed along various pseudo-binary joins, where the end-members are Na-disilicate and one of the lanthanide sesquioxides (i.e., Ce2O3, Pr2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3 and Yb2O3), have been measured using the double-bob Archimedean method. The present results show that the addition of any lanthanide to Na-disilicate leads to an increase in the melt density and that the melt density increases with increasing atomic number of the lanthanide. From the present density data set, the molar volumes of these melts have been calculated and the partial molar volumes of each lanthanide sesquioxide in these melts have been determined using a linear regression through each pseudo-binary join (i.e., Na-disilicate - lanthanide sesquioxide). This study indicates ideal behaviour with respect to the molar volume (i.e., a linear variation of the molar volume along each pseudo-binary join) for Na-silicate melts containing up to 10 mol% of lanthanide oxide. Comparison between the partial molar volumes of lanthanide sesquioxides obtained in this study and the molar volumes of molten lanthanide sesquioxides given in the literature raise the possibility however that this ideality is not maintained along the entire Na-disilicate - lanthanide sesquioxide pseudo-binary joins. Excess volumes of mixing appear to be required to describe the combined volumetric data set.

Courtial, P.; Dingwell, D. B.

2004-12-01

129

Hybrid materials based on lanthanide organic complexes: a review.  

PubMed

A great deal of research has been carried out on lanthanide organic complex-based organic-inorganic hybrid materials in the last decade. This critical review begins with a formulation of the fundamentals of lanthanide organic complex luminescence, and presents various current designed ideas, synthetic routes, luminescence behaviors and potentials of the latest advanced (a) sol-gel materials, (b) mesoporous materials, (c) titania materials, (d) ionic liquids and ionogels, (e) polymers, and (f) bifunctional magnetic-optical composites based on lanthanide organic complexes. Finally, challenges and opportunities for further improvement of organic-inorganic hybrid luminescent materials based on lanthanide organic complexes will be discussed. PMID:22977887

Feng, Jing; Zhang, Hongjie

2012-09-13

130

The use of decylamine for the extraction of actinides and lanthanides from carbonate solutions  

SciTech Connect

This paper studies the extraction of actinides (Th, U, Pu, Am, Cm, Bk, Cf) and the lanthanides (Ce, Eu, Yb, Lu) from solutions of ammonium bicarbonate by decylamine (DA) chloride in chloroform. The following order of extraction of the actinides in various oxidation states was established: Me(III) >Me(IV) > (Me(VI). The extraction of trivalent transplutonium elements increases in the series Cf < Bk < Cm < Am, and that of the rare earth elements Lu < Yb < Eu. The distribution coefficients decrease with increasing HCO/sup -//sub 3/ ion concentration and, conversely, increase with increasing concentration of the metal and extraction reagent. In the system NH/sub 4/HCO/sub 3/-DA in chloroform, a high separation factor of the Am-U pair, equal to 10/sup 3/, is observed.

Karalov, Z.K.; Bukina, T.V.; Myasoedov, B.F.; Rodionova, L.M.

1985-09-01

131

Determination of tetracycline in milk by using nucleotide/lanthanide coordination polymer-based ternary complex.  

PubMed

The meta-organic coordination polymers have been emerged as fascinating nanomaterials because of their tunable nature. In this work, we employed lanthanide coordination polymer self-assembled from adenosine monophosphate (AMP) and europium ion (Eu(3+)) as receptor reagent and citrate (Cit) as ancillary ligand to construct a fluorescent sensor for the detection of tetracycline (Tc) in milk. The co-coordination of Cit and Tc with Eu(3+) on the surface of the coordination polymer AMP/Eu leads to the formation of ternary complex which emitted strong fluorescence due to the removal of coordinated water molecules and an intramolecular energy transfer from Tc to Eu(3+). The fluorescent intensity of Eu(3+) displayed a good linear response to Tc concentrations in the range of 0.1-20?M with a detection limit of 60nM. This method was successfully applied to determine the levels of Tc in milk, which is the first application of coordination polymer as a fluorescent sensor in real sample. Compared with other Eu(3+)-based fluorescent methods for Tc detection, the presented method allows simple, direct analysis of Tc without requiring special reaction media or complicated prepreparation processes. This straightforward strategy could be extended to the preparation of other lanthanide coordination polymer-based fluorescent probes for applications in biosensing, imaging, drug delivery, and so on. PMID:23907076

Tan, Hongliang; Ma, Chanjiao; Song, Yonghai; Xu, Fugang; Chen, Shouhui; Wang, Li

2013-07-17

132

Shift Registers  

NSDL National Science Digital Library

All About Circuits is a website that âÂÂprovides a series of online textbooks covering electricity and electronics.â Written by Tony R. Kuphaldt, the textbooks available here are wonderful resources for students, teachers, and anyone who is interested in learning more about electronics. This specific section, Shift Registers, is the twelfth chapter in Volume IV âÂÂDigital. A few of the topics covered in this chapter include: Serial-in, serial-out shift register, Parallel-in, parallel-out shift register, and Ring counters. Diagrams and detailed descriptions of concepts are included throughout the chapter to provide users with a comprehensive lesson. Visitors to the site are also encouraged to discuss concepts and topics using the All About Circuits discussion forums (registration with the site is required to post materials).

Kuphaldt, Tony R.

2008-07-18

133

Cys-Ph-TAHA: a lanthanide binding tag for RDC and PCS enhanced protein NMR.  

PubMed

Here we present Cys-Ph-TAHA, a new nonadentate lanthanide tag for the paramagnetic labelling of proteins. The tag can be easily synthesized and is stereochemically homogenous over a wide range of temperatures, yielding NMR spectra with a single set of peaks. Bound to ubiquitin, it induced large residual dipolar couplings and pseudocontact shifts that could be measured easily and agreed very well with the protein structure. We show that Cys-Ph-TAHA can be used to label large proteins that are biochemically challenging such as the Lac repressor in a 90 kDa ternary complex with DNA and inducer. PMID:21892794

Peters, Fabian; Maestre-Martinez, Mitcheell; Leonov, Andrei; Kova?i?, Lidija; Becker, Stefan; Boelens, Rolf; Griesinger, Christian

2011-09-04

134

Protein measurement with the Folin phenol reagent  

Microsoft Academic Search

Since 1922 when Wu proposed the use of the Folin phenol reagent for the measurement of proteins (l), a number of modified analytical pro- cedures ut.ilizing this reagent have been reported for the determination of proteins in serum (2-G), in antigen-antibody precipitates (7-9), and in insulin (10). Although the reagent would seem to be recommended by its great sen- sitivity

O. H. Lowry; N. J. Rosebrough; A. Lewis Farr; R. J. Randall

1951-01-01

135

MPM: III. Reagents for Macroanalytical Methods  

Center for Food Safety and Applied Nutrition (CFSAN)

... Except where noted, technical grade reagents are acceptable. Alcohol -- Use 95% commercial ethanol unless otherwise specified. ... More results from www.fda.gov/food/foodscienceresearch/laboratorymethods

136

Sorption of lanthanides on smectite and kaolinite  

Microsoft Academic Search

Experiments were carried out to investigate the sorption of the complete lanthanide series (Ln or rare earth elements, REE) on a kaolinite and an a Na-montmorillonite at 22°C over a wide range of pH (3–9). Experiments were conducted at two ionic strengths, 0.025 and 0.5 M, using two different background electrolytes (NaNO3 or NaClO4) under atmospheric conditions or N2 flow

Frédéric Coppin; Gilles Berger; Andreas Bauer; Sylvie Castet; Michel Loubet

2002-01-01

137

Hexaaza macrocyclic complexes of the lanthanides  

SciTech Connect

The authors systematically investigate the conditions leading to the metal-templated macrocyclic synthesis and obtain by an appropriate combination of counterions and experimental conditions, two series of complexes of the macrocyclic ligand L = C/sub 22/H/sub 26/N/sub 6/, with every lanthanide(III) ion except radioactive Pm. Their synthesis, characterization, and properties are described here. 13 references, 2 figures.

De Cola, L.; Smailes, D.L.; Vallarino, L.M.

1986-05-07

138

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

139

The Shifting \\  

Microsoft Academic Search

In the past decade, numerous ICT-related investigation powers have been introduced or extended. Have these shifted the balance between criminal investigation and privacy? Do governments allow more privacy infringements for the sake of law enforcement than they used to do? As a first step towards answering these questions, this paper presents the results of a case study of communications interception

Bert-Jaap Koops

2003-01-01

140

Effective core potential methods for the lanthanides  

SciTech Connect

In this paper a complete set of effective core potentials (ECPs) and valence basis sets for the lanthanides (Ce to Lu) are derived. These ECPs are consistent not only within the lanthanide series, but also with the third-row transition metals which bracket them. A 46-electron core was chosen to provide the best compromise between computational savings and chemical accuracy. Thus, the 5[ital s] and 5[ital p] are included as outer'' core while all lower energy atomic orbitals (AOs) are replaced with the ECP. Generator states were chosen from the most chemically relevant +3 and +2 oxidation states. The results of atomic calculations indicate that the greatest error vs highly accurate numerical potential/large, even-tempered basis set calculations results from replacement of the large, even-tempered basis sets with more compact representations. However, the agreement among atomic calculations remains excellent with both basis set sizes, for a variety of spin and oxidation states, with a significant savings in time for the optimized valence basis set. It is expected that the compact representation of the ECPs and valence basis sets will eventually encourage their use by computational chemists to further explore the bonding and reactivity of lanthanide complexes.

Cundari, T.R.; Stevens, W.J. (Contribution from the Center for Advanced Research in Biotechnology, National Institutes of Standards and Technology, Rockville, Maryland 20850 (United States) Department of Chemistry, Memphis State University, Memphis, Tennessee 38152 (United States))

1993-04-01

141

Plutonium alteration phases from lanthanide borosilicate glass  

SciTech Connect

A prototype lanthanide borosilicate (LaBS) glass containing 10 mass % plutonium was reacted with water vapor at 200 C for periods of 14 to 56 days. These tests, while not designed to replicate specific conditions that may be found in a potential geologic repository (e.g., Yucca Mountain), have been shown to accelerate alteration phase formation. The surfaces of the glass samples, along with alteration phases, were examined with a transmission electron microscope (TEM). Tests of 14 days produced macroscopic ({approximately} 20 {micro}m) crystallites of a plutonium-lanthanide silicate. An extensive alteration layer was found on the glass surface containing amorphous aluminosilicate layered with bands of a cryptocrystalline plutonium silicate. After 56 days of testing, additional alteration phases were formed, including a strontium lanthanide oxide phase. One of the options for disposal of surplus plutonium, particularly for impure residues that may be unfit for production of MOX fuel, is vitrification followed by geologic disposal. Since geologic disposal requires a passive system to isolate the radiotoxic elements from the biosphere, it is important to understand the possible corrosion mechanisms of the waste form.

Fortner, J.A.; Mertz, C.J.; Chamberlain, D.C.; Bates, J.K.

1997-10-01

142

Coordination of lanthanides by two polyamino polycarboxylic macrocycles: formation of highly stable lanthanide complexes  

Microsoft Academic Search

The formation constants of a few lanthanide complexes with DOTA (1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid) and TETA (1,4,8,11-tetraazacyclotetradecane-N,N',N'',N'''-tetraacetic acid) have been measured by potentiometric and competition methods. The ligand DOTA forms the most stable lanthanide chelates known so far (log K\\/sub ML\\/ = 28.2-29.2) while the stability of the TETA compounds at 80 °C (log K\\/sub ML\\/ = 14.5-16.5) is comparable to the

M. F. Loncin; J. F. Desreux; E. Merciny

1986-01-01

143

Selective catalysis by lanthanides dispersed on supports (silica, alumina and active carbon)  

Microsoft Academic Search

The dispersed lanthanide catalysts were prepared by the reaction of support materials (silica, alumina and active carbon) with a homogeneous solution of lanthanides dissolved in liquid ammonia. Their catalytic properties for hydrogenation varied markedly with changes in support and levels of lanthanide loading. The matrix materials influenced the forms of lanthanide present, strongly affecting the catalytic activity and selectivity. For

T. Konishi; E. Suda; H. Imamura

1995-01-01

144

Bioavailabiltiy of Lanthanides to Freshwater Organisms: Speciation, Accumulation and Toxicity  

Microsoft Academic Search

The lanthanides consist of a group of fifteen homologous metals and together with scandium (Sc) and yttrium (Y) they are known as the rare earth elements (REE). Contrasting to what this name suggests they are not rare at all and lanthanides can be found in most soils and sediments in quantities comparable to those of Pb and Cd. However, their

L. Weltje

2003-01-01

145

Lanthanide Extraction with 2,5-Dimethyl-2-Hydroxyhexanoic Acid.  

National Technical Information Service (NTIS)

This research is concerned with the solvent extraction into chloroform of the lanthanides, using 2,5-dimethyl-2-hydroxyhexanoic acid (DMHHA). This acid is the first alpha -hydroxy aliphatic acid to be studied as an extracting agent for the lanthanides. Th...

J. H. Miller

1977-01-01

146

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

147

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 (Pittsburgh, PA); Cohen, Seth (Boston, MA); Xu, Jide (Berkeley, CA)

2008-10-28

148

Diphenic acid as an analytical reagent  

Microsoft Academic Search

Diphenic acid behaves as a selective reagent for the estimation of thorium in presence of phosphate, arsenate, molybdate, alkaline, earths, copper, cadmium, lead, bismuth, tin, aluminium, chromium, nickel, cobalt, zinc, manganese, magnesium and palladium. Thorium can be successfully separated from the cerite earths by the reagent from solutions having thoria: earth oxide ratio 1:26 by single precipitation and by double

Gurupada Banerjee

1955-01-01

149

TREATMENT OF MTBE USING FENTON'S REAGENT  

EPA Science Inventory

This paper addresses the removal of MTBE from water, using Fenton's Reagent. Although complete mineralization of MTBE by Fenton's Reagent was not achieved, greater than 99% destruction of MTBE was realized. This was accomplished at a Fe+2:H2O2 ratio of 1:1 and one hour of contact...

150

Induced chemical shifts in the NMR spectrum of methyl petroselinate  

Microsoft Academic Search

The use of a pseudo contact shift reagent, (Eu[fod]3), to obtain simplified NMR spectra of a typical long chain monounsaturated fatty acid methyl ester, methyl petroselinate,\\u000a is described. Spectra were obtained in which individual methylene groups are identifiable from their splitting patterns. Non-equivalent\\u000a splitting patterns were observed for the methine protons with varying amounts of reagent used. The effect of

G. J. Boudreaux; A. V. Bailey; V. W. Tripp

1972-01-01

151

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

Microsoft Academic Search

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

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

2012-01-01

152

40 CFR 160.83 - Reagents and solutions.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Reagents and solutions. 160.83 Section 160... GOOD LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 160.83 Reagents and solutions. All reagents and solutions in the laboratory...

2011-07-01

153

40 CFR 160.83 - Reagents and solutions.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Reagents and solutions. 160.83 Section 160... GOOD LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 160.83 Reagents and solutions. All reagents and solutions in the laboratory...

2012-07-01

154

40 CFR 792.83 - Reagents and solutions.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Reagents and solutions. 792.83 Section 792... GOOD LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 792.83 Reagents and solutions. All reagents and solutions in the laboratory...

2010-07-01

155

40 CFR 792.83 - Reagents and solutions.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Reagents and solutions. 792.83 Section 792... GOOD LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 792.83 Reagents and solutions. All reagents and solutions in the laboratory...

2013-07-01

156

Inactivation of rabies diagnostic reagents by gamma radiation.  

PubMed Central

Treatment of CVS-11 rabies adsorbing suspensions and street rabies infected mouse brains with gamma radiation resulted in inactivated reagents that are safer to distribute and use. These irradiated reagents were as sensitive and reactive as the nonirradiated control reagents.

Gamble, W C; Chappell, W A; George, E H

1980-01-01

157

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

158

21 CFR 866.3480 - Respiratory syncytial virus serological reagents.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Respiratory syncytial virus serological reagents. 866.3480... § 866.3480 Respiratory syncytial virus serological reagents. (a) Identification. Respiratory syncytial virus serological reagents are devices...

2013-04-01

159

40 CFR 160.83 - Reagents and solutions.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Reagents and solutions. 160.83 Section 160.83 Protection...Facilities Operation § 160.83 Reagents and solutions. All reagents and solutions in the laboratory areas shall be...

2013-07-01

160

21 CFR 606.65 - Supplies and reagents.  

Code of Federal Regulations, 2010 CFR

...Frequency of testing Anti-human globulin Each day of use. Blood grouping reagents Do. Lectins Do. Antibody screening and reverse grouping cells Do. Hepatitis test reagents Each run. Syphilis serology reagents Do....

2009-04-01

161

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

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Rubeola (measles) virus serological reagents...Serological Reagents § 866.3520 Rubeola (measles) virus serological reagents. (a) Identification. Rubeola (measles) virus serological...

2009-04-01

162

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

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Rubeola (measles) virus serological reagents...Serological Reagents § 866.3520 Rubeola (measles) virus serological reagents. (a) Identification. Rubeola (measles) virus serological...

2010-04-01

163

21 CFR 866.3135 - Coccidioides immitis serological reagents.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Coccidioides immitis serological reagents...Serological Reagents § 866.3135 Coccidioides immitis serological reagents. (a) Identification. Coccidioides immitis serological...

2009-04-01

164

21 CFR 866.3135 - Coccidioides immitis serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Coccidioides immitis serological reagents...Serological Reagents § 866.3135 Coccidioides immitis serological reagents. (a) Identification. Coccidioides immitis serological...

2010-04-01

165

21 CFR 866.3140 - Corynebacterium spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Corynebacterium spp. serological reagents...Serological Reagents § 866.3140 Corynebacterium spp. serological reagents. (a) Identification. Corynebacterium spp. serological...

2010-04-01

166

21 CFR 866.3140 - Corynebacterium spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Corynebacterium spp. serological reagents...Serological Reagents § 866.3140 Corynebacterium spp. serological reagents. (a) Identification. Corynebacterium spp. serological...

2009-04-01

167

21 CFR 866.3700 - Staphylococcus aureus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Staphylococcus aureus serological reagents...Serological Reagents § 866.3700 Staphylococcus aureus serological reagents. (a) Identification. Staphylococcus aureus serological...

2010-04-01

168

21 CFR 866.3700 - Staphylococcus aureus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Staphylococcus aureus serological reagents...Serological Reagents § 866.3700 Staphylococcus aureus serological reagents. (a) Identification. Staphylococcus aureus serological...

2009-04-01

169

Inactivation of rabies diagnostic reagents by gamma radiation  

SciTech Connect

Treatment of CVS-11 rabies adsorbing suspensions and street rabies infected mouse brains with gamma radiation resulted in inactivated reagents that are safer to distribute and use. These irradiated reagents were as sensitive and reactive as the nonirradiated control reagents.

Gamble, W.C.; Chappell, W.A.; George, E.H.

1980-11-01

170

21 CFR 606.65 - Supplies and reagents.  

Code of Federal Regulations, 2013 CFR

...Each day of use. Blood grouping reagents Do. Lectins Do. Antibody screening and reverse grouping cells Do. Hepatitis test reagents Each run. Syphilis serology reagents Do. Enzymes Each day of use. (d) Supplies and...

2013-04-01

171

Luminescent lanthanide complexes for advanced photonic applications  

Microsoft Academic Search

The lanthanide compounds containing unsymmetrical beta-diketone with [2.2]paracyclophane moiety in particular the europium complex with three [1-(4-[2.2]paracyclophanyl)]-3-phenylpropane-1,3-dione and 1,10-phenanthroline has been synthesized for the first time. The optical properties of [2.2]paracyclophane-derived ligands (symmetrical beta-diketones and their respective N-phenylimines) as well as those of the europium complex were studied by UV-visible and luminescence spectroscopy. The diastereomers (racemic chiral, (R*,R*)- and achiral

Lada N. Puntus; Elena V. Sergeeva; Dmitrii Y. Antonov; Konstantin A. Lyssenko; Francois Kajzar

2010-01-01

172

Multicentric comparison of single portion reagents and liquid reagents for thromboelastometry.  

PubMed

Thromboelastometry ROTEM (Pentapharm, Munich, Germany) is a viscoelastic method of whole blood clotting assessment with applications in perioperative hemostasis and hematology. The different tests available for the investigation of distinct coagulation aspects are performed with combinations of liquid reagents. The use of liquid reagents for the ROTEM measurement requires several pipetting steps, which complicates their application in clinical routine even though pipetting is performed semiautomatically. New single portion reagents (SPR) containing in one vial all lyophilized reagents necessary for each test have been recently developed. SPR require only addition of blood into the single-use reagent vial in a unique pipetting step in order to mix reagents with the blood sample. Our study compared SPR and standard liquid reagents (Pentapharm) in 21 blood samples from normal subjects and 46 samples from patients in three study centers. Following ROTEM tests were performed: EXTEM (extrinsically activated TEM), INTEM (intrinsically activated TEM), FIBTEM (fibrin-based TEM), APTEM (aprotinin-controlled TEM) and HEPTEM (heparin-insensitive TEM). In the second part of the study, the stability of SPR at 37 degrees C was also assessed on 23 blood samples in one center. Very good correlation was found between SPR and liquid reagents for all clotting parameters (correlation coefficient between 0.85-0.99). The SPR reagents showed excellent stability against thermic stress and the measurements were easier to perform than with the conventional liquid reagents system. PMID:19657320

Rahe-Meyer, Niels; Solomon, Cristina; Vorweg, Matthias; Becker, Sandra; Stenger, Katja; Winterhalter, Michael; Lang, Thomas

2009-04-01

173

Ultraviolet spectroscopic determination of five lanthanide elements without prior separation  

SciTech Connect

This investigation has resulted in an analytical method for the quantitative determination of total lanthanide concentration in aqueous solution by absorbance at 240 nm followed by quantitative determination of individual lanthanide ion concentrations by the use of concentration-responsive absorption peaks in the 190-235 nm region. The 240-nm peak is present and is proportional to concentration regardless of the ligand employed to complex the lanthanides (including H[sub 2]O). The individual lanthanide/ligand peaks in the 190-235 nm region were selected on the basis of their separation from one another, their linearity of absorbance vs. concentration, and their statistical reliability based on replicate sample analyses. Lanthanides involved in this investigation were La[sup +3], Nd[sup +3], Eu[sup +3], Ho[sup +3], and Yb[sup +3]. Ligands ultimately selected for complexation were citrate for La[sup +3], Nd[sup +3], Nd[sup +3], and Ho[sup +3], and DTPA for Eu[sup +3], Ho[sup +3], and Yb[sup +3]. When large amounts of heavy metal ions were present, a modified method was developed with citrate as the only complexing ligand for all five lanthanides. The method here developed permits the analyses of lanthanide ions in aqueous solution without prior separation and involves the use of comparatively inexpensive instrumentation (UV absorption spectrophotometer). 12 refs., 5 figs., 15 tabs.

Citron, I.M.; Hanlon, P.M.; Arthur, S. (Fairleigh Dickinson Univ., Teaneck, NJ (United States))

1993-06-01

174

21 CFR 866.3205 - Echovirus serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3205 Echovirus serological reagents. (a) Identification....

2013-04-01

175

21 CFR 866.3250 - Erysipelothrix rhusiopathiae serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3250 Erysipelothrix rhusiopathiae serological reagents. (a)...

2013-04-01

176

21 CFR 866.3370 - Mycobacterium tuberculosis immunofluorescent reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3370 Mycobacterium tuberculosis immunofluorescent reagents. (a)...

2013-04-01

177

21 CFR 866.3470 - Reovirus serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3470 Reovirus serological reagents. (a) Identification....

2013-04-01

178

21 CFR 866.3165 - Cryptococcus neoformans serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3165 Cryptococcus neoformans serological reagents. (a)...

2013-04-01

179

21 CFR 866.3020 - Adenovirus serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3020 Adenovirus serological reagents. (a) Identification....

2013-04-01

180

21 CFR 866.3500 - Rickettsia serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3500 Rickettsia serological reagents. (a) Identification....

2013-04-01

181

New reagent for uranium - plutonium partitioning.  

National Technical Information Service (NTIS)

We have investigated the feasibility of achieving uranium-plutonium partition of the Purex Process by using a new reagent: Uranous nitrate - hydroxylamine nitrate. Laboratory test tube studies and uranium-plutonium partitioning runs have shown that pluton...

M. Germain B. Gillet J. Y. Pasquiou

1990-01-01

182

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

183

Selective Metals Determination with Photoreversible Reagents.  

National Technical Information Service (NTIS)

Photoreversible compounds are used as metal ion sensing reagents. Particularly, spiropyrans modified to incorporate a metal ion complexation site such as, 8-hydroxyquinoline, onto the backbone of the spiropyran, are used as the photoreversible metal ion s...

G. E. Collins

2000-01-01

184

Determination of Hydroxylamine with Nessler Reagent.  

National Technical Information Service (NTIS)

Hydroxylamine forms strong color complexes with ninhydrin and Nessler solution, two of the standard reagents for ammonia. In the case of ninhydrin, ammonium salts and hydroxylamine have the same molar absorptivity; hydroxylamine is probably reduced to amm...

W. N. Fishbein

1966-01-01

185

Preparation and Development of Enterovirus Reagents.  

National Technical Information Service (NTIS)

The selection of three semiannual progress reports describes part of NIAID's Research Reference Reagents Program. Reports are included from (1) Baylor University of Houston, Texas, (2) the California State Department of Public Health of Berkeley and (3) U...

J. L. Melnick E. H. Lennette H. A. Wenner

1967-01-01

186

Development of rapid diagnostic reagents for measles.  

PubMed

Measles diagnosis has thus far been based on clinical symptoms in daily clinical practice. However, atypical cases are not uncommon; a simple and rapid method of measles diagnosis is clinically required. Lateral flow-based rapid diagnosis reagents are widely used for point-of-care testing in Japanese clinics, because it does not require special skills and facilities. We have developed a rapid diagnostic reagent for measles that employs the lateral flow method. The lower limit of detection of this reagent was almost the same for recombinant proteins of wild-type and vaccine strain, at 5.1 x 10(3) copies/test. This lower limit of detection and the specificity of this reagent suggest its efficacy for the diagnosis of measles infection. PMID:19663696

Hasegawa, Takehiro; Asaeda, Ayumi; Hamaguchi, Yukio; Numazaki, Kei

2009-08-01

187

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

188

The Crystal Structure of Lanthanide Zirconates  

NASA Astrophysics Data System (ADS)

The lanthanide zirconates of composition Ln2Zr2O7 (Ln = La-Gd) are of interest for use in inert matrix fuels and nuclear wasteforms. The series undergoes a pyrochlore to fluorite phase transition as a function of the Ln atomic radii. The phase transition has been attributed to disordering of both the cation and the anion [1]. We have undertaken a synthesis of the lanthanide zirconate series Ln2Zr2O7 (Ln = La-Gd), Ln0.2Zr0.8O1.9 (Ln = Tb-Yb) and NdxHo2-xZr2O7 (0

Clements, Richard; Kennedy, Brendan; Ling, Christopher; Stampfl, Anton P. J.

2010-03-01

189

Environment effects on the CO vibrational shifts in erbium complexes: a quantum chemical study.  

PubMed

The stability of lanthanide complexes and the efficiency of the energy transfer process, which makes these molecules interesting materials for technological applications, are correlated to the chemical environment surrounding the metal ion. In particular the efficiency depends on the relative position of the antenna (the ligand moiety that acts as photon absorption center) and the lanthanide ion (the emitting center), while the stability of the complex is correlated to the strength of the coordination between the rare earth and the ligands. For these reasons, knowledge of the structural properties of the complex is an interesting task to achieve. Since a large number of ligand structures hold the carboxylate group (COO(-)), which is used as an anchor for binding the antennae to the lanthanide ion, in this work we will show how the vibrational shifts of this group, induced by the interactions between the carboxylate moiety and the metal center of the lanthanide complex, can be used for obtaining in a simple way information on the structure of the chemical environment surrounding the lanthanide ion. PMID:18956859

Ottonelli, Massimo; Musso, Gianfranco; Dellepiane, Giovanna

2008-10-29

190

Effects of salicylate and lanthanides on outer hair cell motility and associated gating charge.  

PubMed

Salicylate, one of the most widely used drugs, is known to induce reversible tinnitus and hearing loss. Salicylate interferes with outer hair cells (OHCs), which are believed to underlie normal auditory frequency selectivity and sensitivity. In the present experiments, the effects of salicylate and lanthanides on OHC motility and nonlinear capacitance were investigated by using isolated guinea-pig OHCs while attempting to avoid inadvertent intracellular pressure change, which itself can affect OHC motility and capacitance. Either extracellularly or intracellularly applied salicylate reduced nonlinear peak capacitance (Cmpk) and shifted the voltage at peak capacitance to depolarized levels. Concentration-response curves for reduction in Cmpk by salicylate and GdCl3 revealed a half-maximal concentration and Hill coefficient of 1.6 mM and 1.0, and 0.6 mM and 1.2, respectively. In comparable groups of OHCs, the normal Cmpk values of which were near 40 pF, average Cmpk decreased to 28 and 36 pF for intracellularly and extracellularly applied salicylate, respectively. Salicylate reduced, but did not completely block, the voltage-induced length change. Extracellularly, but not intracellularly, applied lanthanide blocked voltage-induced movement and capacitance almost completely. After intracellular trypsin treatment, salicylate reduced voltage-dependent capacitance reversibly, suggesting that salicylate directly acts on the sensor/motor and not via effects on intracellular structures, such as the subsurface cisternae. The results are consistent with the hypothesis that the dissociated, charged form of salicylate directly interacts with the sensor/motor on the inner aspect of the OHC plasma, whereas lanthanides interact on the outer aspect. PMID:8756420

Kakehata, S; Santos-Sacchi, J

1996-08-15

191

Separation of Minor Actinides from Lanthanides by Dithiophosphinic Acid Extractants  

SciTech Connect

The selective extraction of the minor actinides (Am(III) and Cm(III)) from the lanthanides is an important part of advanced reprocessing of spent nuclear fuel. This separation would allow the Am/Cm to be fabricated into targets and recycled to a reactor and the lanthanides to be dispositioned. This separation is difficult to accomplish due to the similarities in the chemical properties of the trivalent actinides and lanthanides. Research efforts at the Idaho National Laboratory have identified an innovative synthetic pathway yielding new regiospecific dithiophosphinic acid (DPAH) extractants. The synthesis provides DPAH derivatives that can address the issues concerning minor actinide separation and extractant stability. For this work, two new symmetric DPAH extractants have been prepared. The use of these extractants for the separation of minor actinides from lanthanides will be discussed.

D. R. Peterman; M. R. Greenhalgh; R. D. Tillotson; J. R. Klaehn; M. K. Harrup; T. A. Luther; J. D. Law; L. M. Daniels

2008-09-01

192

Stabilization of Actinides and Lanthanides in Unusually High Oxidation States.  

National Technical Information Service (NTIS)

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 pr...

P. G. Eller R. A. Penneman

1986-01-01

193

Extraction of Tervalent Lanthanides with Acidic Organophosphorus Compounds.  

National Technical Information Service (NTIS)

The equilibrium extraction behavior for a series of tervalent lanthanide ions (Ln exp 3+ ) using a chloroform solution containing di(2-ethyl-hexyl)phosphoric acid (HDEHP), diphenylphosphinic acid (HDPP), dibutylphosphorothioic acid (HDBPT), di-n-octylphos...

S. Motomizu H. Freiser

1985-01-01

194

Heptamethylindenyl lanthanide(III) complexes of lanthanum, neodymium, and erbium  

Microsoft Academic Search

Both the steric bulk and the electronic character of this ligand resulting from the seven methyl groups favor the stabilization of the lanthanide-carbon bonds. Alkali metal salts of heptamethylindenide(Hmi) were used as precursors of the lanthanide complexes. Lanthanum, erbium or neodymium chlorides were added to a stoichiometric amount of potassium Hmi, allowing the mixture to stand at 25°C ca 2

Minoru Tsutsui; Li Ban Chen; David E. Bergbreiter; T. Ken Miyamoto

1982-01-01

195

Structure of Glass-Forming Melts - Lanthanide in Borosilicates  

SciTech Connect

Over the past few years, we studied several complex Na2O-Al2O3-B2O3-SiO2 glass systems to answer key questions: effects of melt chemistry on solubility of lanthanide oxides; lanthanide solution behavior, and intermediate-range ordering in the melts. This paper summarizes our currently understanding on rare earth elements in borosilicate glasses, covering solution behavior, solubility limits, crystalization and phase separation.

Li, Hong; Li, Liyu; Qian, Morris; Strachan, Denis M.; Wang, Zheming

2004-05-17

196

Reaction of lanthanide elements with Fe-Cr alloy  

NASA Astrophysics Data System (ADS)

During steady-state irradiation of metal fuel in fast reactors, lanthanide fission products react with the Fe-base cladding and cause wastage of the cladding inner surface. In order to provide the basis of the cladding wastage modeling, the authors conducted isothermal annealing tests of diffusion couples consisting of Fe-12wt.%Cr alloy and lanthanide alloy, 13La-24Ce-12Pr-39Nd-12Sm (in wt.%), which simulates fission yield of lanthanide elements. In the temperature range of 773-923 K, Fe diffused into the lanthanide alloy side and formed Fe2RE precipitates, where RE stands for lanthanide element mixture. Cr did not migrate evidently. The lanthanide elements diffused into the Fe-Cr side and formed the distinct reaction zone. This reaction zone showed two-phase structure of (Fe,Cr)17RE2 and (Fe,Cr)3RE. Ce and Sm were concentrated in the Fe2RE and (Fe,Cr)17RE2 phases. The thickness of reaction zone in the Fe-Cr side grew in proportion to the square root of annealing time. The activation energy of the reaction zone growth was determined, which can be the basis of the cladding wastage modeling.

Inagaki, Kenta; Ogata, Takanari

2013-10-01

197

{sup 31}P NMR study of the complexation of TBP with lanthanides and actinides in solution and in a clay matrix  

SciTech Connect

Goal was to use NMR to study TBP/lanthanide complexes in the interlayer or on edge sites of clays. Work in this laboratory yielded details of the complexation of Eu(NO{sub 3}){sub 3} and Pr(NO{sub 3}){sub 3} with TBP in hexane solution; this information is crucial to interpretation of results of NMR studies of the complexes exchanged into clays. The solution {sup 31}P-chemical shift values were improved by repeating the studies on the lanthanide salts dissolved directly into neat TBP. NMR studies of these neat solutions of the Eu(NO{sub 3}){sub 3}{lg_bullet}3TBP-complex and the Pr(NO{sub 3}){sub 3}{lg_bullet}3TBP-complex show that the {sup 31}P chemical shift remains relatively constant for TBP: lanthanide ratios below 3: 1. At higher ratios, the chemical shift approaches that of free TBP, indicating rapid exchange of TBP between the free and complexed state. Exchange of these complexes into the clay hectorite yielded discrete {sup 31}P-NMR signals for the Eu{lg_bullet}TBP complex at -190 ppm and free TBP at -6 ppm. Adsorption of the Pr{lg_bullet}TBP complex yielded broad signals at 76 ppm for the complex and -6 ppm for free TBP. There was no evidence of exchange between the incorporated complex and the free TBP.

Hartzell, C.J. [Northern Arizona Univ., Flagstaff, AZ (United States)

1994-07-24

198

U.S. VETERINARY IMMUNE REAGENTS NETWORK: PROGRESS WITH POULTRY IMMUNE REAGENTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

A major obstacle to advances in veterinary immunology and disease control is the lack of sufficient immunological reagents specific for ruminants, swine, poultry, equine and aquaculture species. Sets of reagents, i.e., monoclonal (mAb) and polyclonal antibodies, that can identify the major leukocyt...

199

Optical properties of lanthanide dyes for spectral conversion encapsulated in porous silica nanoparticles  

NASA Astrophysics Data System (ADS)

Lanthanide based dyes belong to one of the most promising fields of photovoltaic research, combining high quantum yields and large spectral shift. However, many challenges are faced when working with lanthanide dyes for spectral conversion: their thermal and chemical stability, which can greatly influence the shelf-life of the dyes; the absorption band position, which depends on the organic part of the dye, the so called "antenna"; self-quenching mechanisms, which lead to a photoluminescence emission loss. The chemical composition of the surrounding environment of the dyes has a fundamental role in their properties. In this paper, the optical and PLQY (photoluminescence quantum yield) properties of an europium-based dye embedded in a silica matrix are reported. The in-house synthesized dye consists of a bis(2- (diphenylphosphino)phenyl)ether oxide (DPEPO) ligand and three hexafluoroacetylacetonate (hfac) co-ligands coordinating a central europium ion. The dye has been included in porous core-shell particles, to study its optical properties once embedded in a solid dielectric matrix. The optical properties of the resulting samples have been characterized by photoluminescence emission and PLQY measurements. The results have been compared with data obtained from a commercially available dye (BASF Lumogen family) in similar conditions.

Pizzol, Paolo; Marques-Hueso, Jose; Robertson, Neil; Freris, Isidora; Bellotto, Luca; Meyer, Thomas J. J.; Richards, Bryce S.

2012-05-01

200

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

201

Lanthanide binding and IgG affinity construct: Potential applications in solution NMR, MRI, and luminescence microscopy  

PubMed Central

Paramagnetic lanthanide ions when bound to proteins offer great potential for structural investigations that utilize solution nuclear magnetic resonance spectroscopy, magnetic resonance imaging, or optical microscopy. However, many proteins do not have native metal ion binding sites and engineering a chimeric protein to bind an ion while retaining affinity for a protein of interest represents a significant challenge. Here we report the characterization of an immunoglobulin G-binding protein redesigned to include a lanthanide binding motif in place of a loop between two helices (Z-L2LBT). It was shown to bind Tb3+ with 130 nM affinity. Ions such as Dy3+, Yb3+, and Ce3+ produce paramagnetic effects on NMR spectra and the utility of these effects is illustrated by their use in determining a structural model of the metal-complexed Z-L2LBT protein and a preliminary characterization of the dynamic distribution of IgG Fc glycan positions. Furthermore, this designed protein is demonstrated to be a novel IgG-binding reagent for magnetic resonance imaging (Z-L2LBT:Gd3+ complex) and luminescence microscopy (Z-L2LBT: Tb3+ complex).

Barb, Adam W; Ho, Tienhuei Grace; Flanagan-Steet, Heather; Prestegard, James H

2012-01-01

202

Partitioning of Light Lanthanides from Actinides by Solvent Extraction With TBP.  

National Technical Information Service (NTIS)

A solvent extraction process was developed for removing the light lanthanides (La, Ce, Pr, Nd) from americium-curium produced by neutron irradiation of 239Pu. The light lanthanides are extracted into 30% tributyl phosphate (TBP) in normal paraffin hydroca...

J. M. McKibben H. P. Holcomb D. A. Orth W. E. Prout W. C. Scotten

1974-01-01

203

The structure of polymer-supported triphenylphosphine ditriflate: a potentially useful reagent in organic synthesis.  

PubMed

The structure of a polymer-supported version of the Hendrickson "POP" reagent, prepared by the reaction of polymer-supported triphenylphosphine oxide 1 with triflic anhydride, is established as an equilibrium mixture of polymer-supported triphenylphosphine ditriflate 3 (delta 79.4 ppm) and polymer-supported phosphonium anhydride 4 (delta 73.3 ppm). The (31)P NMR chemical shift reported previously for 3 is shown to be incorrect. PMID:18498194

Petersson, Maria J; Jenkins, Ian D; Loughlin, Wendy A

2008-05-23

204

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

205

Lanthanides in metallic nuclear fuels: Their behavior and methods for their control  

Microsoft Academic Search

The thermodynamic and experimental basis is given for using dopant additives to bind lanthanides as intermetallic compounds in metallic nuclear fuels. Lanthanide fission products are a major factor in limiting the lifetime of the fuel, because they migrate to the fuel slug peripheral surface where they participate in fuel-cladding chemical interactions (FCCI) with the D9 or HT9 steel cladding. Lanthanide

R. D. Mariani; D. L. Porter; T. P. O'Holleran; S. L. Hayes; J. R. Kennedy

2011-01-01

206

Lanthanide-doped luminescent nano-bioprobes: from fundamentals to biodetection  

NASA Astrophysics Data System (ADS)

Trivalent lanthanide (Ln3+)-doped luminescent inorganic nanoparticles (NPs), characterized by long-lived luminescence, large Stokes and/or anti-Stokes shifts, narrow emission bands and high photochemical stability, are considered to be promising candidates as luminescent bioprobes in biomedicine and biotechnology. In this feature article, we provide a brief overview of the most recent advances in Ln3+-doped luminescent inorganic NPs as sensors, which covers from their chemical and physical fundamentals to biodetection, such as controlled synthesis methodology, surface modification chemistry, optical physics, and their promising applications in diverse bioassays, with an emphasis on heterogeneous and homogeneous in vitro biodetection. Finally, some of the most important emerging trends and future efforts toward this active research field are also proposed.

Liu, Yongsheng; Tu, Datao; Zhu, Haomiao; Ma, En; Chen, Xueyuan

2013-01-01

207

A lanthanide complex doped silica thin film for detecting trace chemical toxins  

NASA Astrophysics Data System (ADS)

A highly luminescent lanthanide metal--ligand complex was doped into a mesoporous silica sol-gel matrix for the development of a nanosensor to detect trace toxic chemicals. The metal ion Eu^3+ was coordinated with various organic ligands to produce different self-assembling compounds that exhibit different sensitivity to targeted chemical toxins. Under ultra-violet excitation, the compound exhibited intense, long-lived millisecond phosphorescence with a large Stokes shift. A detector was fabricated by doping a silica sol-gel thin film matrix with the Eu^3+ compound and was exposed to liquid and gas phase toxins. Upon exposure, the compound underwent fast fluorescence quenching and the emission/source intensity ratio was measured as a function of time for various concentrations of toxins.

Como, John; Hope-Weeks, Louisa; Cheng, Kelvin

2009-10-01

208

Lanthanide-doped luminescent nano-bioprobes: from fundamentals to biodetection.  

PubMed

Trivalent lanthanide (Ln(3+))-doped luminescent inorganic nanoparticles (NPs), characterized by long-lived luminescence, large Stokes and/or anti-Stokes shifts, narrow emission bands and high photochemical stability, are considered to be promising candidates as luminescent bioprobes in biomedicine and biotechnology. In this feature article, we provide a brief overview of the most recent advances in Ln(3+)-doped luminescent inorganic NPs as sensors, which covers from their chemical and physical fundamentals to biodetection, such as controlled synthesis methodology, surface modification chemistry, optical physics, and their promising applications in diverse bioassays, with an emphasis on heterogeneous and homogeneous in vitro biodetection. Finally, some of the most important emerging trends and future efforts toward this active research field are also proposed. PMID:23223801

Liu, Yongsheng; Tu, Datao; Zhu, Haomiao; Ma, En; Chen, Xueyuan

2013-02-21

209

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

2013-01-31

210

Reagents for HIV\\/SIV Vaccine Studies  

Microsoft Academic Search

Since last year's edition of this section, a large number of new attenuated SIVs and SHIVs have been added to the collection. We have attempted to include all strains we could find in this reagent overview. If there are any that are not included, we would very much appreciate hearing about them; we will make sure they will be added

Carla Kuiken; Patrick Rose; Sonia Vasil; Satish Pillai

211

Tritioacetylating reagents and processes for preparation thereof  

DOEpatents

Novel acetylating and tritioacetylating reagents suitable for preparation of nonlabelled and radiolabelled organic compounds. N-acetoxynaphthalimide, N-tritioacetoxyphthalimide, N-tritioacetoxysuccinimide, N-tritioacetoxynaphthalimide and processes of their preparation. The invention also concerns synthesis of nonlabelled acetylated and tritioacetylated organic compounds from precursors containing a free --NH.sub.2, --SH or --OH group.

Saljoughian, Manoucher (Moraga, CA); Morimoto, Hiromi (El Cerrito, CA); Williams, Philip G. (Oakland, CA); Than, Chit (Lafayette, CA)

2000-01-01

212

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

213

Gear shift control mechanism  

Microsoft Academic Search

A gear shift control mechanism is described comprising: multiple shift rods directed substantially parallel to one another, each rod carrying a shift fork for axial movement; a shift lever supported for pivotal movement about a first axis directed parallel to the axes of the shift rods and for pivotal movement about a second axis directed substantially perpendicular to the axes

Janson

1987-01-01

214

Luminescent lanthanide complexes with stereocontrolled tris(2-pyridylmethyl)amine ligands: chirality effects on lanthanide complexation and luminescence properties.  

PubMed

A series of tris(2-pyridylmethyl)amines including one and two asymmetric centers were synthesized in a stereo-controlled fashion as potential ligands of lanthanide cations. The reaction of chiral pyridylethyl methanesulfonates and bis(pyridylmethyl)amines occurred via an S(N)2 mechanism with complete inversion of asymmetric centers and gave the stereocontrolled tris(2-pyridylmethyl)amines, the stereochemical purity of which was ascertained by GPC, NMR, X-ray, and polarimetry experiments. They formed stable Tb(3+) and Eu(3+) complexes having 1:1, 1:2, and 1:3 stoichiometry (metal:ligand) in CH(3)CN solutions. NMR and UV titration experiments revealed that their complexation behaviors were rarely influenced by ligand chirality but significantly affected by the nature of the counteranion and the concentration ratio of metal to ligand. The Tb(3+) and Eu(3+) complexes with these tripodal ligands exhibited characteristic luminescence spectra upon excitation for pyridine chromophores (260 nm), the intensities of which were largely dependent on the ligand chirality. The meso isomer of the disubstituted tripods particularly exhibited the enhanced terbium luminescence ca. three times more than its diastereomer and un- and monosubstituted tripods. Direct excitation at the lanthanide center had similar chirality effects on the luminescence profiles, indicating that the stereochemistry of the employed ligand largely influenced the lanthanide emitting processes. Since the ligand chirality finely modified the local coordination environments around the lanthanide center, the use of stereocontrolled ligands is applicable in design of the luminescent lanthanide complexes. PMID:14632510

Yamada, Takashi; Shinoda, Satoshi; Sugimoto, Hideki; Uenishi, Jun-ichi; Tsukube, Hiroshi

2003-12-01

215

Lattice energies and polarizability volumes of lanthanide monoaluminates  

NASA Astrophysics Data System (ADS)

Lattice energies ?LH? of the entire series of lanthanide aluminum perovskites LnAlO3, Ln=Ce-Lu, have been determined for the first time by means of the Born-Haber cycle. The results have been compared for LnAlO3 obtained by other methods, with cubic lanthanide sesquioxides (C-Ln2O3) and lanthanide aluminum garnets (Ln3Al5O12). Polarizability volumes ?I of LnAlO3 have been estimated by the Clausius-Mossotti equation. It has been found that the partial derivative (??LH?/??I)T corresponds by magnitude to an upper limit of elastic moduli of the same crystals.

Petrov, D.; Angelov, B.

2012-09-01

216

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

217

Extraction of tervalent lanthanides with acidic organophosphorus compounds  

SciTech Connect

The equilibrium extraction behavior for a series of tervalent lanthanide ions (Ln/sup 3 +/) using a chloroform solution containing di(2-ethyl-hexyl)phosphoric acid (HDEHP), diphenylphosphinic acid (HDPP), dibutylphosphorothioic acid (HDBPT), di-n-octylphosphorodithoic acid (HDOPDT), or di(2-ethylhexyl)phosphorodithioic acid (HDEHPDT), either alone or combined with adduct forming agents is studied. The extracted species are Ln(DEHP)/sub 3/(HDEHP)/sub 3/, Ln(DPP)/sub 3/(HDPP)/sub 3/, Ln(DBPT)/sub 3/, and are Ln(DBPT)/sub 3/(HDEHP)B in the presence of o-phen and its analogs (B). Extraction constants for the lanthanides follow the order HDPP > HDEHP > HDBPT >> HDOPDT. HDPP was the most selective of all the extractants examined. HDOPDT and HDEHPDT were found to be ineffective lanthanide extractants. 23 refs., 9 figs., 5 tabs.

Motomizu, S.; Freiser, H.

1985-01-01

218

Purificaiton of Lanthanides for Large Neutrino Detectors: Thorium Removal from Gadolinium Chloride  

SciTech Connect

Metal-loaded liquid scintillators are the detectors of choice for various neutrino experiments. Procedures have been developed to transfer metals into organic liquids by solvent extraction or direct dissolution of a metallic compound. Traces of natural radioactivity introduced into the scintillator with the metal may produce undesirable backgrounds. Measurements using a {sup 229}Th tracer indicate that the inclusion of a pH-controlled partial hydrolysis and filtration prior to the preparation of a gadolinium-loading compound can reduce thorium by a factor of {approx}100. This 'self-scavenging' procedure has the advantage that it uses only reagents encountered in the production process. Addition of non-elemental scavengers such as iron, or the use of solvent extraction or ion exchange procedures can be avoided. It also improves the optical transmission in the blue region by removing traces of iron. This purification method has potential applications to the large-scale production of other metal-loaded liquid scintillators and for the removal of traces of thorium in the industrial production of lanthanides.

Yeh, M.; Cumming, J.B.; Hans, S.; Hahn, R.L.

2010-06-01

219

21 CFR 866.3120 - Chlamydia 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 § 866.3120 Chlamydia serological reagents. (a)...

2013-04-01

220

21 CFR 866.3395 - Norovirus 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 § 866.3395 Norovirus serological reagents. (a)...

2013-04-01

221

21 CFR 866.3145 - Coxsackievirus 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 § 866.3145 Coxsackievirus serological reagents. (a)...

2013-04-01

222

21 CFR 866.3740 - Streptococcus 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 § 866.3740 Streptococcus spp. serological reagents. (a)...

2013-04-01

223

21 CFR 866.3490 - Rhinovirus 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 § 866.3490 Rhinovirus serological reagents. (a)...

2013-04-01

224

21 CFR 866.3660 - Shigella 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 § 866.3660 Shigella spp. serological reagents. (a)...

2013-04-01

225

21 CFR 866.3740 - Streptococcus spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...Identification. Streptococcus spp. serological reagents are devices that consist of antigens and antisera (excluding streptococcal exoenzyme reagents made from enzymes secreted by streptococci) used in serological tests to identify...

2009-04-01

226

21 CFR 866.3740 - Streptococcus spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...Identification. Streptococcus spp. serological reagents are devices that consist of antigens and antisera (excluding streptococcal exoenzyme reagents made from enzymes secreted by streptococci) used in serological tests to identify...

2010-04-01

227

Blood Grouping Reagent, Anti-Fya ALBAsera®  

Center for Biologics Evaluation and Research (CBER)

... Blood Grouping Reagent, Anti-Fy a ALBAsera®. STN: 125341 Proper Name: Blood Grouping Reagents, Anti-Fy a Tradename ... More results from www.fda.gov/biologicsbloodvaccines/bloodbloodproducts/approvedproducts

228

21 CFR 866.3870 - Trypanosoma spp. serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3870 Trypanosoma spp. serological reagents. (a) Identification....

2013-04-01

229

21 CFR 866.3200 - Echinococcus spp. serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3200 Echinococcus spp. serological reagents. (a) Identification....

2013-04-01

230

21 CFR 866.3380 - Mumps virus serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3380 Mumps virus serological reagents. (a) Identification....

2013-04-01

231

21 CFR 866.3700 - Staphylococcus aureus serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3700 Staphylococcus aureus serological reagents. (a) Identification....

2013-04-01

232

21 CFR 866.3930 - Vibrio cholerae serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3930 Vibrio cholerae serological reagents. (a) Identification....

2013-04-01

233

21 CFR 866.3780 - Toxoplasma gondii serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3780 Toxoplasma gondii serological reagents. (a) Identification....

2013-04-01

234

21 CFR 866.3600 - Schistosoma spp. serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3600 Schistosoma spp. serological reagents. (a) Identification....

2013-04-01

235

21 CFR 866.3330 - Influenza virus serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3330 Influenza virus serological reagents. (a) Identification....

2013-04-01

236

21 CFR 866.3270 - Flavobacterium spp. serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3270 Flavobacterium spp. serological reagents. (a) Identification....

2013-04-01

237

21 CFR 866.3550 - Salmonella spp. serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3550 Salmonella spp. serological reagents. (a) Identification....

2013-04-01

238

21 CFR 864.4010 - General purpose reagent.  

Code of Federal Regulations, 2010 CFR

...Reagents used in tests for more than one individual chemical substance or ligand are general purpose reagents (e.g., Thermus aquaticus (TAQ) polymerase, substrates for enzyme immunoassay (EIA)). (b) Classification. Class I...

2010-04-01

239

21 CFR 864.4010 - General purpose reagent.  

Code of Federal Regulations, 2010 CFR

...Reagents used in tests for more than one individual chemical substance or ligand are general purpose reagents (e.g., Thermus aquaticus (TAQ) polymerase, substrates for enzyme immunoassay (EIA)). (b) Classification. Class I...

2009-04-01

240

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...

241

Threshold Voltage Engineering by Lanthanide Doping of the MOS Gate Stack  

SciTech Connect

With the replacement of traditional polysilicon and silicon dioxide by metal gates and high-k dielectrics, respectively, in the MIS gate stack for the 45 nm technology node, higher than expected device threshold voltages have been observed due to the effect of Fermi-level pinning. While the debate as to the exact cause of Fermi-level pinning is ongoing, several attempts (capping layers, new gate metal compositions) have been made to curb this effect. In this paper, the tuning of metal gate work function by ion implantation is investigated as a tool for controlling the threshold voltage. Lanthanide incorporation is used to achieve a flat-band voltage shift of more than-1 V for n-MOS capacitors. It is shown that by adjusting dose and energy, the flat-band voltage shift can be tuned to a desired value, without substantial damage to the insulating quality of the gate. This translates to an effective shift in the threshold voltage.

Fet, A.; Haeublein, V. [Fraunhofer Institut fuer Integrierte Systeme und Bauelementetechnologie Schottkystrasse 10, 91058 Erlangen (Germany); Ryssel, H. [Fraunhofer Institut fuer Integrierte Systeme und Bauelementetechnologie Schottkystrasse 10, 91058 Erlangen (Germany); Lehrstuhl fuer Elektronische Bauelemente, Cauerstrasse 6, 91058 Erlangen (Germany)

2008-11-03

242

Method for extracting lanthanides and actinides from acid solutions  

DOEpatents

A process for the recovery of actinide and lanthanide values from aqueous acidic solutions with an organic extractant having the formula: ##STR1## where .phi. is phenyl, R.sup.1 is a straight or branched alkyl or alkoxyalkyl containing from 6 to 12 carbon atoms and R.sup.2 is an alkyl containing from 3 to 6 carbon atoms. The process is suitable for the separation of actinide and lanthanide values from fission product values found together in high level nuclear reprocessing waste solutions.

Horwitz, E. Philip (Naperville, IL); Kalina, Dale G. (Naperville, IL); Kaplan, Louis (Lombard, IL); Mason, George W. (Clarendon Hills, IL)

1985-01-01

243

Elemental distributions and lanthanide uptake in nude mice  

NASA Astrophysics Data System (ADS)

The relative elemental weight distribution in tumors and other organs of nude mice was measured using particle induced X-ray emission (PIXE) analysis. Several lanthanide (ytterbium, dysprosium and neodymium in this report) uptakes in nude mice have been investigated to establish how well lanthanides can localize tumors in mice. It was found that ytterbium was not retained in tumors but dysprosium and neodymium localize in tumors. The elemental distributions in tumors and some organs are shown in figures and some characteristics apparent from the results are discussed. Permanent address: National Institute of Preventive Medicine, Taipei, Taiwan.

Chau-Chin, Wei; Sheng-Liang, Huang; Wu-Shiung, Hsu; Chia-Yu, Wang; Chung-Ho, Chien; Ming-Ji, Chou

1987-03-01

244

21 CFR 660.30 - Reagent Red Blood Cells.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 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....

2009-04-01

245

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

246

21 CFR 58.83 - Reagents and solutions.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 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...

2013-04-01

247

21 CFR 660.30 - Reagent Red Blood Cells.  

Code of Federal Regulations, 2010 CFR

...2012-04-01 2012-04-01 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....

2012-04-01

248

Organometallic reagents and protocols for synthesis  

Microsoft Academic Search

The addition of vinyl, aryl and alkynyl Grignard reagents to propargyl alcohols for the direct synthesis of dihydroxydienes (7), furans (9), butenolides (10) and enediyne alcohols (11) from a one-pot reaction involving a putative magnesium chelate intermediate (3) is described. Treatment of 5-bromo-1,3-pentadiene with indium metal in the presence of carbonyl compounds resulted in ?-pentadienylation to generate 1,4-dienes (30). Dehydration

Alex G Fallis; Pat Forgione; Simon Woo; Stephanie Legoupy; Sandrine Py; Curtis Harwig; Tanya Rietveld

2000-01-01

249

Seebach's Conjunctive Reagent Enables Double Cyclizations  

PubMed Central

When ketones flanked on both sides by nucleophilic atoms react with Seebach’s nitropropenyl pivaloate reagent, direct couplings take place to give two new ring systems and three bonds. cis-Ring fusions are observed in unions leading to 5,5-, 5,6-, and 6,6-bicycles. Densely functionalized and rigid frameworks may be rapidly formed by the chemistry described herein.

Chandler, Brent D.; Roland, Jason T.; Li, Yukai; Sorensen, Erik J.

2011-01-01

250

Collection of radon with solid oxidizing reagents  

Microsoft Academic Search

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 (Oâ\\/sup +\\/SbFâ⁻) or hexafluoroiodine hexafluoroantimonate (IFâ\\/sup +\\/SbFâ⁻) reagent, is described. The air is passed though a drying

Lawrence Stein; Frederick A. Hohorst

1982-01-01

251

Production of latex agglutination reagents for pneumococcal serotyping  

PubMed Central

Background The current ‘gold standard’ for serotyping pneumococci is the Quellung test. This technique is laborious and requires a certain level of training to correctly perform. Commercial pneumococcal latex agglutination serotyping reagents are available, but these are expensive. In-house production of latex agglutination reagents can be a cost-effective alternative to using commercially available reagents. This paper describes a method for the production and quality control (QC) of latex reagents, including problem solving recommendations, for pneumococcal serotyping. Results Here we describe a method for the production of latex agglutination reagents based on the passive adsorption of antibodies to latex particles. Sixty-five latex agglutination reagents were made using the PneuCarriage Project (PCP) method, of which 35 passed QC. The other 30 reagents failed QC due to auto-agglutination (n=2), no reactivity with target serotypes (n=8) or cross-reactivity with non-target serotypes (n=20). Dilution of antisera resulted in a further 27 reagents passing QC. The remaining three reagents passed QC when prepared without centrifugation and wash steps. Protein estimates indicated that latex reagents that failed QC when prepared using the PCP method passed when made with antiserum containing ? 500 ?g/ml of protein. Sixty-one nasopharyngeal isolates were serotyped with our in-house latex agglutination reagents, with the results showing complete concordance with the Quellung reaction. Conclusions The method described here to produce latex agglutination reagents allows simple and efficient serotyping of pneumococci and may be applicable to latex agglutination reagents for typing or identification of other microorganisms. We recommend diluting antisera or removing centrifugation and wash steps for any latex reagents that fail QC. Our latex reagents are cost-effective, technically undemanding to prepare and remain stable for long periods of time, making them ideal for use in low-income countries.

2013-01-01

252

Structure and properties of lanthanide halides  

NASA Astrophysics Data System (ADS)

Lanthanum and cerium bromides and chlorides form isomorphous alloy systems with the UCl3 type structure. These scintillating alloys exhibit high luminosity and proportional response, making them the first scintillators comparable to room temperature semiconductors for gamma spectroscopy; Ce(III) activated lanthanum bromide has recently enabled scintillating gamma ray spectrometers with < 3% FWHM energy resolutions at 662 keV. However brittle fracture of these materials impedes development of large volume crystals. Low fracture stress and perfect cleavage along prismatic planes cause material cracking during and after crystal growth. These and other properties pose challenges for material production and post processing; therefore, understanding mechanical behavior is key to fabricating large single crystals, and engineering of robust detectors and systems. Recent progress on basic structure and properties of the lanthanide halides is reported here, including thermomechanical and thermogravimetric analyses, hygroscopicity, yield strength, and fracture toughness. Observations including reversible hydrate formation under atmospheric pressure, loss of stoichiometry at high temperature, anisotropic thermal expansion, reactivity towards common crucible materials, and crack initiation and propagation under applied loads are reported. The fundamental physical and chemical properties of this system introduce challenges for material processing, scale-up, and detector fabrication. Analysis of the symmetry and crystal structure of this system suggests possible mechanisms for deformation and crack initiation under stress. The low c/a ratio and low symmetry relative to traditional scintillators indicate limited and highly anisotropic plasticity cause redistribution of residual process stress to cleavage planes, initiating fracture. This proposed failure mechanism and its implications for scale up to large diameter crystal growth are also discussed.

Doty, F. P.; McGregor, Douglas; Harrison, Mark; Findley, Kip; Polichar, Raulf

2007-10-01

253

Containment of Spray Reagents in TLC Spot Detection  

NASA Astrophysics Data System (ADS)

A recent suggestion to visualize spots on thin layer plates by applying phosphomolybdic acid reagent with a cotton ball (1) may not be suitable for all visualization reagents especially concentrated sulfuric acid. If spraying a reagent with a power pac type device is preferred for this or some other reason, we suggest spraying the reagent inside of a twist tie-sealed, clear-plastic kitchen garbage bag. In this way, spray reagents are completely contained obviating the need for spraying the plates in a fume hood, and cleanup is simple. Literature Cited 1. Lee, A. W. M.; Zengpei, Z. J. Chem. Educ., 1996, 73, 358.

Krause, Josef G.

1996-10-01

254

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

255

Improved preparation of anhydrous lanthanide chlorides under mild conditions  

Microsoft Academic Search

Oxides or carbonates of lanthanides (Ln) are converted under mild conditions into the corresponding solvated anhydrous chlorides LnCl3(ether)n by hydrogen chloride produced in situ from thionyl chloride and water in the presence of 1,l2-dimethoxyethane under mild conditions.

Daniela Belli Dell'Amico; Fausto Calderazzo; Cinzia della Porta; Alessandra Merigo; Paolo Biagini; Gabriele Lugli; Trixie Wagner

1995-01-01

256

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

Microsoft Academic Search

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

Vyacheslav A. Sharov; G. V. Bezdenezhnykh

1981-01-01

257

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

258

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.

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

2009-01-01

259

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

260

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

261

Experimental and Theoretical Studies on Biologically Active Lanthanide (III) Complexes  

NASA Astrophysics Data System (ADS)

The complexation ability and the binding mode of the ligand coumarin-3-carboxylic acid (HCCA) to La(III), Ce(III), Nd(III), Sm(III), Gd(III) and Dy(III) lanthanide ions (Ln(III)) are elucidated at experimental and theoretical level. The complexes were characterized using elemental analysis, DTA and TGA data as well as 1H NMR and 13C NMR spectra. FTIR and Raman spectroscopic techniques as well as DFT quantum chemical calculations were used for characterization of the binding mode and the structures of lanthanide(III) complexes of HCCA. The metal-ligand binding mode is predicted through molecular modeling and energy estimation of different Ln-CCA structures using B3LYP/6-31G(d) method combined with a large quasi-relativistic effective core potential for lanthanide ion. The energies obtained predict bidentate coordination of CCA- to Ln(III) ions through the carbonylic oxygen and the carboxylic oxygen. Detailed vibrational analysis of HCCA, CCA- and Ln(III) complexes based on both calculated and experimental frequencies confirms the suggested metal-ligand binding mode. The natural bonding analysis predicts strongly ionic character of the Ln(III)-CCA bonding in the- complexes studied. With the relatively resistant tumor cell line K-562 we obtained very interesting in-vitro results which are in accordance with our previously published data concerning the activity of lanthanide(III) complexes with other coumarin derivatives.

Kostova, I.; Trendafilova, N.; Georgieva, I.; Rastogi, V. K.; Kiefer, W.

2008-11-01

262

Tunable selectivity of lanthanide ion exchange within a coordination polymer.  

PubMed

The exchange of lanthanide(III) ions (Ln(3+)) between a solution and a coordination polymer (CP) formed by cerium(III) or samarium(III) ion and an organophosphorous ligand has been studied. The CPs exhibit distinctive Ln(3+) affinity that varies with a small change in its framework, depending on the central Ln(3+). PMID:23842409

Tasaki-Handa, Yuiko; Ooi, Kenta; Tanaka, Mikiya; Wakisaka, Akihiro

2013-01-01

263

High-Temperature Density of Lanthanide-Bearing Silicate Melts  

Microsoft Academic Search

The lanthanides are of interest in the geosciences, despites usually occurring as minor or trace elements in rock-forming minerals although they can be essential constituents of some minerals. In general, they are partitioned more extremely than major elements making them more sensitive indicators of the petrological processes that occur. Therefore, they are a powerful tool in order to trace the

P. Courtial; D. Dingwell

2002-01-01

264

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

265

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

266

Lanthanide-binding helix-turn-helix peptides: Solution structure of a designed metallonuclease  

PubMed Central

A designed lanthanide-binding chimeric peptide based on the strikingly similar geometries of the EF-hand and helix-turn-helix (HTH) motifs was investigated by NMR and CD spectroscopy and found to retain the same overall solution structure of the parental motifs. CD spectroscopy showed that the 33-mer peptide P3W folds on binding lanthanides, with an increase in ?-helicity from 20% in the absence of metal to 38% and 35% in the presence of excess Eu(III) and La(III) ions, respectively. The conditional binding affinities of P3W for La(III) (5.9 ± 0.3 ?M) and for Eu(III) (6.2 ± 0.3 ?M) (pH 7.8, 5 mM Tris) were determined by tryptophan fluorescence titration. The La(III) complex of peptide P3, which differs from P3W by only one Trp-to-His substitution, has much less signal dispersion in the proton NMR spectra than LaP3W, indicating that the Trp residue is a critical hydrophobic anchor for maintaining a well-folded helix-turn-helix structure. A chemical-shift index analysis indicates the metallopeptide has a helix-loop-helix secondary structure. A structure calculated by using nuclear Overhauser effect and other NMR constraints reveals that P3W not only has a tightly folded metal-binding loop but also retains the ??? corner supersecondary structure of the parental motifs. Although the solution structure is undefined at both the N and C termini, the NMR structure confirms the successful incorporation of a metal-binding loop into a HTH sequence.

Welch, Joel T.; Kearney, William R.; Franklin, Sonya J.

2003-01-01

267

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

PubMed Central

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 loop positions (denoted L, R, and S) of the model protein interleukin-1? and varied the length of the spacer between the LBT and the protein (denoted 1-3). Luminescence studies demonstrate that all nine constructs bind Tb3+ tightly in the low nanomolar range. No significant change in the fusion protein occurs from insertion of the LBT, as shown by two X-ray crystallographic structures of the IL1?-S1 and IL1?-L3 constructs and for the remaining constructs by comparing 1H-15N-HSQC NMR spectra with wild-type IL1?. Additionally, binding of LBT-loop IL1? proteins to their native binding partner in vitro remains unaltered. X-ray crystallographic phasing was successful using only the signal from the bound lanthanide. Large residual dipolar couplings (RDCs) could be determined by NMR spectroscopy for all LBT-loop-constructs and revealed that the LBT-2 series were rigidly incorporated into the interleukin-1? structure. The paramagnetic NMR spectra of loop-LBT mutant IL1?-R2 were assigned and the ?? tensor components were calculated based on RDCs and pseudocontact shifts (PCSs). A structural model of the IL1?-R2 construct was calculated using the paramagnetic restraints. The current data provide support that encodable LBTs serve as versatile biophysical tags when inserted into loop regions of proteins of known structure or predicted via homology modelling.

Barthelmes, Katja; Reynolds, Anne M.; Peisach, Ezra; Jonker, Hendrik R. A.; DeNunzio, Nicholas J.; Allen, Karen N.; Imperiali, Barbara; Schwalbe, Harald

2011-01-01

268

Lanthanide sorption on smectitic clays in presence of cement leachates  

NASA Astrophysics Data System (ADS)

Due to their potential retention capacity, clay minerals have been proposed for use in the engineered barriers for the storage of high-level radioactive actinides in deep geological waste repositories. However, there is still a lack of data on the sorption of actinides in clays in conditions simulating those of the repositories. The present article examines the sorption of two lanthanides (actinide analogues) in a set of smectitic clays (FEBEX bentonite, MX80 bentonite, hectorite, saponite, Otay montmorillonite, and Texas montmorillonite). Distribution coefficients ( Kd) were determined in two media: water and 0.02 mol L -1 Ca, the latter representing the cement leachates that may modify the chemical composition of the water in contact with the clay. The Kd values of the lanthanides used in the experiments (La and Lu) varied greatly (25-50 000 L kg -1) depending on the ionic medium (higher values in water than in the Ca medium), the initial lanthanide concentration (up to three orders of magnitude decrease inversely with lanthanide concentration), and the examined clay (up to one order of magnitude for the same lanthanide and sorption medium). Freundlich and Langmuir isotherms were used to fit sorption data to allow comparison of the sorption parameters among smectites. The model based on the two-site Langmuir isotherms provided the best fit of the sorption data, confirming the existence of sorption sites with different binding energies. The sites with higher sorption affinity were about 6% of the total sorption capacity in the water medium, and up to 17% in the Ca medium, although in this latter site sorption selectivity was lower. The wide range of Kd values obtained regarding the factors examined indicated that the retention properties of the clays should also be considered when selecting a suitable clay for engineered barriers.

Galunin, Evgeny; Alba, María D.; Santos, Maria J.; Abrão, Taufik; Vidal, Miquel

2010-02-01

269

Lanthanide co-ordination frameworks: Opportunities and diversity  

SciTech Connect

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 studied to date than their d-block counterparts. One possible reason for this is that the co-ordination spheres of lanthanide cations are more difficult to control and, in the absence of design strategies for lanthanide co-ordination frameworks, it is significantly more difficult to target materials with specific properties. However, this article highlights some of the exciting possibilities that have emerged from the earliest investigations in this field with new topological families of compounds being discovered from relatively simple framework components, including unusual eight, seven and five-connected framework systems. Our own research, as well as others, is leading to a much greater appreciation of the factors that control framework formation and the resultant observed topologies of these polymers. As this understanding develops targeting particular framework types will become more straightforward and the development of designed polyfunctional materials more accessible. Thus, it can be seen that lanthanide co-ordination frameworks have the potential to open up previously unexplored directions for materials chemistry. This article focuses on the underlying concepts for the construction of these enticing and potentially highly important materials.

Hill, Robert J. [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Long, De-Liang [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Hubberstey, Peter [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Schroeder, Martin [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Champness, Neil R. [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)]. E-mail: Neil.Champness@nottingham.ac.uk

2005-08-15

270

Nonpolar aromatized reagent for coal flotation  

SciTech Connect

Further improvements in flotation technique and techology are necessitated by the widening application of flotation to coals at the extremes of the rank series, with poor flotation properties, the increasing proportions of fine to very fine size fractions and the more stringent requirements on the quality of washery products. New collecting agents have been developed; they differ fundamentally from the kerosenes and reagent AF-2 used hitherto, in both chemical composition and method of production. The new agents are no longer by-products; they are made as goal products in the petroleum refineries. They consist predominantly of aromatic hydrocarbons with maximum flotation activity; the activity of reagents increases in the order paraffins ..-->.. naphthenes ..-->.. aromatics. In contrast to the linear chains in paraffins and the nonplanar (3-dimensional) rings in naphthenes, the benzene ring has a coplanar structure: the carbon and hydrogen atoms lie in a single plane, while the ..pi..-electron clouds of the carbon atoms lie at right angles to the ring plane and parallel to each other. This structure makes aromatic hydrocarbons superior with respect to adsorption bonding between the molecules of collecting agent and the coal particle surfaces; they most closely match the properties of coals, since the basic structural unit in the latter is a polycyclic aromatic nucleus. The new nonpolar aromatized reagent AAR-2 corresponds to these requirements and has been proposed for commercial use. AAR-2 has a high flotation activity, selectivity and stability, which reduces the costs of flotation. AAR-2 is made by the catalytic cracking of petroleum vacuum distillates on an aluminum silicate catalyst.

Kotkin, A.M.; Rozhnova, E.E.; Vas'ko, I.P.

1981-01-01

271

Feasibility of the electrochemical way in molten fluorides for separating thorium and lanthanides and extracting lanthanides from the solvent  

NASA Astrophysics Data System (ADS)

An alternative way of reprocessing nuclear fuel by hydrometallurgy could be using treatment with molten salts, particularly fluoride melts. Moreover, one of the six concepts chosen for GEN IV nuclear reactors (Technology Roadmap http://gif.inel.gov/roadmap/) is the molten salt reactor (MSR). The originality of the concept is the use of molten salts as liquid fuel and coolant. During the running of the reactor, fission products, particularly lanthanides, accumulate in the melt and have to be eliminated to optimise reactor operation. This study concerns the feasibility of the separation actinides lanthanides solvent by selectively electrodepositing the elements to be separated on an inert (Mo, Ta) or a reactive (Ni) cathodic substrate in molten fluoride media. The main results of this work lead to the conclusions that:The solvents to be used for efficient separation must be fluoride media containing lithium as cation.Inert substrates are suitable for actinide/lanthanide separation; nickel substrate is more suitable for the extraction of lanthanides from the solvent, owing to the depolarisation occurring in the cathodic process through alloy formation.

Chamelot, P.; Massot, L.; Hamel, C.; Nourry, C.; Taxil, P.

2007-01-01

272

Magnetic susceptibility shift selected imaging: MESSI.  

PubMed

Paramagnetic compounds are often used to enhance contrast in MRI by virtue of their increase in the kinetics of the relaxation of water 1H magnetization. Here, we demonstrate a method for contrast enhancement which is based on the resonance frequency shifts caused by the bulk magnetic susceptibility (BMS) effects of such compounds. This involves the frequency selective excitation in the absence of field gradients, during the imaging sequence, of a portion of the water 1H resonance which is rendered inhomogeneous by BMS shifts only. The image which results is of that portion of the sample which gives rise to the portion of the spectrum excited. A phantom sample which simulates some aspects of tissue, particularly blood vessels with different orientations in the magnetic field, was prepared. The contrast enhancement exhibited here avoids some of the distortions attendant to the use of paramagnetic reagents. This new approach can, in principle, utilize the natural BMS differences found in all tissue. PMID:2255239

Xu, Y; Balschi, J A; Springer, C S

1990-10-01

273

Isoquinoline-based lanthanide complexes: bright NIR optical probes and efficient MRI agents.  

PubMed

In the objective of developing ligands that simultaneously satisfy the requirements for MRI contrast agents and near-infrared emitting optical probes that are suitable for imaging, three isoquinoline-based polyaminocarboxylate ligands, L1, L2 and L3, have been synthesized and the corresponding Gd(3+), Nd(3+) and Yb(3+) complexes investigated. The specific challenge of the present work was to create NIR emitting agents which (i) have excitation wavelengths compatible with biological applications and (ii) are able to emit a sufficient number of photons to ensure sensitive NIR detection for microscopic imaging. Here we report the first observation of a NIR signal arising from a Ln(3+) complex in aqueous solution in a microscopy setup. The lanthanide complexes have high thermodynamic stability (log K(LnL) =17.7-18.7) and good selectivity for lanthanide ions versus the endogenous cations Zn(2+), Cu(2+), and Ca(2+) thus preventing transmetalation. A variable temperature and pressure (17)O NMR study combined with nuclear magnetic relaxation dispersion measurements yielded the microscopic parameters characterizing water exchange and rotation. Bishydration of the lanthanide cation in the complexes, an important advantage to obtain high relaxivity for the Gd(3+) chelates, has been demonstrated by (17)O chemical shifts for the Gd(3+) complexes and by luminescence lifetime measurements for the Yb(3+) analogues. The water exchange on the three Gd(3+) complexes is considerably faster (k(ex)(298) = (13.9-15.4) × 10(6) s(-1)) than on commercial Gd(3+)-based contrast agents and proceeds via a dissociative mechanism, as evidenced by the large positive activation volumes for GdL1 and GdL2 (+10.3 ± 0.9 and +10.6 ± 0.9 cm(3) mol(-1), respectively). The relaxivity of GdL1 is doubled at 40 MHz and 298 K in fetal bovine serum (r(1) = 16.1 vs 8.5 mM(-1) s(-1) in HEPES buffer), due to hydrophobic interactions between the chelate and serum proteins. The isoquinoline core allows for the optimization of the optical properties of the luminescent lanthanide complexes in comparison to the pyridinic analogues and provides significant shifts of the excitation energies toward lower values which therefore become more adapted for biological applications. L2 and L3 bear two methoxy substituents on the aromatic core in ortho and para positions, respectively, that further modulate their electronic structure. The Nd(3+) and Yb(3+) complexes of the ligand L3, which incorporates the p-dimethoxyisoquinoline moiety, can be excited up to 420 nm. This wavelength is shifted over 100 nm toward lower energy in comparison to the pyridine-based analogue. The luminescence quantum yields of the Nd(3+) (0.013-0.016%) and Yb(3+) chelates (0.028-0.040%) are in the range of the best nonhydrated complexes, despite the presence of two inner sphere water molecules. More importantly, the 980 nm NIR emission band of YbL3 was detected with a good sensitivity in a proof of concept microscopy experiment at a concentration of 10 ?M in fetal bovine serum. Our results demonstrate that even bishydrated NIR lanthanide complexes can emit a sufficient number of photons to ensure sensitive detection in practical applications. In particular, these ligands containing an aromatic core with coordinating pyridine nitrogen can be easily modified to tune the optical properties of the NIR luminescent lanthanide complexes while retaining good complex stability and MRI characteristics for the Gd(3+) analogues. They constitute a highly versatile platform for the development of bimodal MR and optical imaging probes based on a simple mixture of Gd(3+) and Yb(3+)/Nd(3+) complexes using an identical chelator. Given the presence of two inner sphere water molecules, important for MRI applications of the corresponding Gd(3+) analogues, this result is particularly exciting and opens wide perspectives not only for NIR imaging based on Ln(3+) ions but also for the design of combined NIR optical and MRI probes. PMID:22233349

Caillé, Fabien; Bonnet, Célia S; Buron, Frédéric; Villette, Sandrine; Helm, Lothar; Petoud, Stéphane; Suzenet, Franck; Tóth, Eva

2012-01-10

274

Improvement of the X-ray radiometric method of lanthanides' diagnostics in soils  

NASA Astrophysics Data System (ADS)

There are scarce data on the content of lanthanides in the soils of Russia, which is explained by the difficulties in their identification. The improvement of X-ray radiometric analysis permitted us to analyze a significant group of lanthanides in soils, i.e., La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, and Dy. Methods of diagnostics are developed for different groups of lanthanides. The new procedure permitted achieving high accuracy in the measurement; the limit of the lanthanide identification in soils is equal to 2-5 mg/kg. The new procedure allows revealing the particularities of heavy lanthanides' distribution depending on the lithogenic and anthropogenic factors. The procedure is applicable for revealing the technogenic anomalies of heavy lanthanides and determining their content in soils within positive and weakly negative anomalies.

Savichev, A. T.; Vodyanitskii, Yu. N.

2012-07-01

275

Bis-(N-maleimidomethyl) ether: an antisickling reagent.  

PubMed Central

The interaction of bis-(N-maleimidomethyl) ether with oxyhemoglobin results in covalent linkages of both maleimide groups, converting them to succinyl derivatives of beta93 Cys and beta97 His at their sulfhydryl and imidazolyl side chains, respectively. The resultant hemoglobin is stable, and reveals a left-shifted oxyhemoglobin equilibrium curve in which cooperativity is abolished. This reagent readily traverses the red cell membrane and prevents the sickling reaction upon deoxygenation. It appears to affect none of the activities of the red cell enzymes adversely, nor does it appear to affect the red cell membrane. Since there are several defined effects on the stereochemical status of the molecule conferred by interaction with bis-(N-maleimidomethyl) ether, the precise mechanism of the anitsickling effect remains to be elucidated. A more subtle perturberant will be required to specify a precise antisickling effect. By use of bis-(N-maleimidomethyl) ether a precise locus on the beta chain of human hemoglobin S can be perturbed to produce the desired effect. Images

Zak, S J; Geller, G R; Finkel, B; Tukey, D P; McCormack, M K; Krivit, W

1975-01-01

276

Safe 5-nitrotetrazolate anion transfer reagents.  

PubMed

Silver 5-nitrotetrazolate (1) and copper(ii) 5-nitrotetrazolate 5-nitrotetrazole dihydrate (2) are useful reagents for the synthesis of 5-nitrotetrazole (NT) salts. Both compounds were synthesized and characterized by vibrational spectroscopy (IR and Raman) and differential scanning calorimetry (DSC). In addition, their sensitivity towards friction, shock and electrostatic discharge was tested by standard BAM methods. The extremely high sensitivity of both materials makes the transfer of the NT(-) anion using and hazardous and not suitable for up-scaling. In order to diminish the hazards involved with the transfer of the energetic anion and to render the synthesis of NT salts suitable for an industrial scale the two compounds were stabilized by coordination with a chelating ligand and silver(ethylendiamine) 5-nitrotetrazolate and bis(ethylendiamine)copper(ii) 5-nitrotetrazolate were synthesized in high yields. Both the stabilized NT(-) anion transfer reagents were characterized by analytical and spectroscopic methods. In addition, the crystal structure of the ethylendiamine copper complex was determined: orthorombic, Pbca; a = 7.5200(1), b = 14.0124(2), c = 14.7740(2) A; V = 1556.78(4) A(3). Furthermore, we synthesized triaminocopper(ii) 5-nitrotetrazolate, which has potential as a more environmentally-friendly primary explosive. Lastly, the synthetic potential of the ethylediamine adducts and to form energetic salts of NT was investigated. PMID:19240919

Klapötke, Thomas M; Sabaté, Carles Miró

2009-01-27

277

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

278

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

279

U. S. VETERINARY IMMUNE REAGENTS NETWORK: PROGRESS WITH POULTRY IMMUNE REAGENTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

This poster will present a progress report on the CSREES-funded NRI grant to support a broad community approach to systematically address the immunological reagent gap for the US veterinary immunology research community including for the following groups: ruminants (concentrating on cattle but inclu...

280

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

281

Improving nursing shift-to-shift report.  

PubMed

In 2002, the Winnipeg Regional Health Authority commissioned an external review for improvements to patient care. From this review arose the Achieving Benchmarks through Collaboration Project, which was composed of 32 projects and a number of subprojects. One such subproject dealt with the reconfiguration of the nursing shift-to-shift report. Its mandate was to improve report, thus making it more efficient, effective, and consistent. This article is a review of this reconfiguration. PMID:17149090

Benson, Ember; Rippin-Sisler, Catherine; Jabusch, Kimberly; Keast, Shelley

282

SIMS analysis of multi-diffusion profiles of lanthanides in stabilized zirconias  

Microsoft Academic Search

To get an insight into the mechanism of cation diffusion in yttria stabilized zirconia (YSZ), the diffusion of all stable lanthanides was measured simultaneously. It was possible to identify all lanthanides with SIMS and perform depth profile analysis to get the bulk diffusion coefficients between 1270 and 1700°C.From the analysis of the radius-dependency of the cation diffusion of the lanthanides,

S. Weber; S. Scherrer; H. Scherrer; M. Kilo; M. A. Taylor; G. Borchardt

2003-01-01

283

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

284

Determination of lanthanides in international geochemical reference materials by reversed-phase high-performance liquid chromatography using error propagation theory to estimate total analysis uncertainties.  

PubMed

The weighted least-squares (WLS) regression method was successfully applied to establish calibration curves with variable amounts of lanthanides ranging from 0.002 to 0.430 microg. These curves were employed for the analysis of 13 lanthanides (La-Nd, Sm-Tb, and Ho-Lu) in 12 international geochemical reference materials (IGRM). The separation of the lanthanide group was achieved in approximately 15 min. Dysprosium could not be determined in IGRM because of its co-elution with Yttrium. A linear gradient program of alpha-HIBA eluent with a concentration ranging from 0.05 to 0.5 M (0.1 M OS, pH 3.8 with NH(4)OH, and a flow-rate of 1.0 ml/min) was employed. The detection was performed with a UV-vis system at 658 nm using a post-column reagent of Arsenazo III (0.5 ml/min). With this set of RP-HPLC conditions together with the use of both the ordinary least-squares (OLS) and the WLS regressions, we report the results of the measurements along with the total propagated uncertainties in individual concentration values. The uncertainties were obtained by combining standard errors in both regression parameters (slope and intercept) with those related to the chromatographic peak areas. The straight-line slopes and intercepts calculated by the WLS method provided not only considerably smaller errors than the conventional OLS method but also a much better estimation of the limits of detection. The concentrations calculated were compared with the "most probable" concentration values of these reference materials reported in the literature. Statistically significant agreement was consistently observed between the HPLC data and the literature values. The total uncertainties in estimated concentration values for the WLS were consistently smaller than the respective errors for the OLS. PMID:16631180

Santoyo, E; Guevara, M; Verma, Surendra P

2006-05-02

285

Toward mechanistic understanding of nuclear reprocessing chemistries by quantifying lanthanide solvent extraction kinetics via microfluidics with constant interfacial area and rapid mixing.  

PubMed

The closing of the nuclear fuel cycle is an unsolved problem of great importance. Separating radionuclides produced in a nuclear reactor is useful both for the storage of nuclear waste and for recycling of nuclear fuel. These separations can be performed by designing appropriate chelation chemistries and liquid-liquid extraction schemes, such as in the TALSPEAK process (Trivalent Actinide-Lanthanide Separation by Phosphorus reagent Extraction from Aqueous Komplexes). However, there are no approved methods for the industrial scale reprocessing of civilian nuclear fuel in the United States. One bottleneck in the design of next-generation solvent extraction-based nuclear fuel reprocessing schemes is a lack of interfacial mass transfer rate constants obtained under well-controlled conditions for lanthanide and actinide ligand complexes; such rate constants are a prerequisite for mechanistic understanding of the extraction chemistries involved and are of great assistance in the design of new chemistries. In addition, rate constants obtained under conditions of known interfacial area have immediate, practical utility in models required for the scaling-up of laboratory-scale demonstrations to industrial-scale solutions. Existing experimental techniques for determining these rate constants suffer from two key drawbacks: either slow mixing or unknown interfacial area. The volume of waste produced by traditional methods is an additional, practical concern in experiments involving radioactive elements, both from disposal cost and experimenter safety standpoints. In this paper, we test a plug-based microfluidic system that uses flowing plugs (droplets) in microfluidic channels to determine absolute interfacial mass transfer rate constants under conditions of both rapid mixing and controlled interfacial area. We utilize this system to determine, for the first time, the rate constants for interfacial transfer of all lanthanides, minus promethium, plus yttrium, under TALSPEAK process conditions, as a first step toward testing the molecular mechanism of this separation process. PMID:21888347

Nichols, Kevin P; Pompano, Rebecca R; Li, Liang; Gelis, Artem V; Ismagilov, Rustem F

2011-09-02

286

Instability of orthophthalaldehyde reagent for amino acid analysis.  

PubMed

Determination of amino acids by reversed-phase chromatography of the adduct with orthophthalaldehyde and a thiol is rapid and sensitive. The major recognized adverse feature of this method is the instability of the reaction product, which requires precise control of reaction timing and chromatographic parameters for reliable quantitative application. We report another source of major variability: reagent instability. Deterioration of reagent was noted as low peak heights and peak broadening and was predictable if the premixed reagent was left at room temperature. Restoration of sharp chromatograms was accomplished by addition of mercaptoethanol or sodium metabisulfite. Reagent which was chromatographically inert contained minimal free thiol by direct assay. Free thiol disappearance was markedly slowed by addition of a chelating agent. Excess mercaptoethanol was deleterious. We conclude that reagent deterioration represents oxidation of the thiol, may be reversed by rereduction with minimal thiol or bisulfite, and may be minimized by inclusion of a metal chelator in the reagent. PMID:2817374

May, M E; Brown, L L

1989-08-15

287

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

2012-05-04

288

Efficient Preparation of Isothiocyanates From Dithiocarbamates Using Bromineless Brominating Reagent  

Microsoft Academic Search

For the first time, the crystal structure of a ditribromide reagent 1,1?-(ethane-1,2-diyl)dipyridinium bistribromide (EDPBT) has been determined. Utilizing this thiophilic bromineless brominating agent EDPBT, highly useful synthetic intermediates (alkyl and aryl isothiocyanates) have been achieved directly from dithiocarbamates. EDPBT can be easily prepared from readily available reagents. It has been used as a thiophilic reagent, and its thiophilicity dominates over

Ramesh Yella; Harisadhan Ghosh; Siva Murru; Santosh K. Sahoo; Bhisma K. Patel

2010-01-01

289

Liquid-Phase Oxidation of Organic Reagents in Inorganic Analysis  

Microsoft Academic Search

It was shown that the sensitivity of analytical procedures using organic reagents can be significantly increased if a poorly soluble complex of an element with an analytical reagent is oxidized to the products of complete oxidation of organic compounds (CO2?, H2O, and NH3or N2for nitrogen-containing reagents). Knowing the amount of the consumed oxidant, one can easily determine the amount of

V. P. Zhivopistsev; A. S. Aramelev

2001-01-01

290

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. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23881869

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

2013-07-24

291

Prussian Blue as a Prebiotic Reagent  

NASA Astrophysics Data System (ADS)

Ferrocyanide has been proposed as a potential prebiotic reagent and the complex salt Prussian Blue, Fe4[Fe(CN)6]3, might be an important reservoir of HCN, in the early Earth. HCN is considered the main precursor of amino acids and purine and pyrimidine bases under prebiotic conditions. Recently, we observed the formation of Prussian Blue in spark discharge experiments using saline solutions of ferrous chloride, FeCl2. Using Prussian Blue as starting material in ammonium suspensions, we obtained organic compounds containing nitrogen. These results seem to indicate that Prussian Blue could have been first, a sink of HCN, and then in subsequent reactions, triggered by pH fluctuations, it might have lead to organic life precursors.

Ruiz-Bermejo, M.; Menor-Salván, C.; Osuna-Esteban, S.; Veintemillas-Verdaguer, S.

2009-12-01

292

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

293

PRINCIPLES AND BIOPHYSICAL APPLICATIONS OF LANTHANIDE-BASED PROBES  

Microsoft Academic Search

? Abstract Using luminescent lanthanides, instead of conventional fluorophores, as donor molecules,in resonance,energy transfer measurements,offers many,technical advantages,and opens up a wide range of new,applications. Advantages include farther measurable distances (»100 ? A) with greater accuracy, insensitivity to incomplete label- ing, and the ability to use generic relatively large labels, when necessary. Applications highlighted include the study of ion channels in

Paul R. Selvin

2002-01-01

294

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

295

Lanthanide NIR luminescence for telecommunications, bioanalyses and solar energy conversion  

Microsoft Academic Search

Present-day advanced technologies heavily rely on the exciting magnetic and spectroscopic properties of lanthanide ions. In particular, their ability to generate well-characterized and intense near-infrared (NIR) luminescence is exploited in any modern fiber-optic telecommunication network. In this feature article, we first summarize the whereabouts underlying the design of highly luminescent NIR molecular edifices and materials. We then focus on describing

Jean-Claude G. Bünzli; Svetlana V. Eliseeva

2010-01-01

296

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

297

Lanthanide co-doping of solid electrolytes: AC conductivity behaviour  

Microsoft Academic Search

Solid electrolytes of cubic structure employed in Solid Oxide Fuel Cells (SOFC) like ceria (CeO2) and zirconia (ZrO2) are typically doped with a single selected element from the (Y, lanthanide)-series. Co-doping of ceria with several elements is investigated here in terms of its influence on ionic conductivity. It is found that, for a same total dopant concentration, mixtures of dopants

J. van Herle; D. Seneviratne; A. J. McEvoy

1999-01-01

298

Interfacial Structure in Silicon Nitride Sintered with Lanthanide Oxide  

SciTech Connect

Three independent research groups present a comparison of their structural analyses of prismatic interfaces in silicon nitride densified with the aid of lanthanide oxide Ln{sub 2}O{sub 3}. All three groups obtained scanning transmission electron microscope images which clearly reveal the presence of well-defined Ln segregation sites at the interfaces, and, moreover, reveal that these segregation sites are element-specific. While some results differ across the three research groups, the vast majority exhibits good reproducibility.

Dwyer, C. [University of Oxford; Ziegler, A. [Lawrence Berkeley National Laboratory (LBNL); Shibata, Naoya [University of Tokyo, Tokyo, Japan; Winkelman, G. B. [University of Oxford; Satet, R. L. [Universituet Karlsruhe, Germany; Hoffmann, M. J. [Universituet Karlsruhe, Germany; Cinibulk, M. K. [Air Force Research Laboratory; Becher, Paul F [ORNL; Painter, Gayle S [ORNL; Browning, N. D. [University of California, Davis; Cockayne, D.J.H. [University of Oxford; Ritchie, R O [University of California, Berkeley; Pennycook, Stephen J [ORNL

2006-01-01

299

Actinide(lanthanide)-noble metal alloy phases, preparation and properties  

Microsoft Academic Search

Actinide (A--Th-Cm)-noble metal phases with platinum, palladium, rhodium, and iridium (--B)- and lanthanide-noble metal phases with platinum and palladium have been prepared by reduction of corresponding oxides or fluorides in the presence of noble metals by extremely purified hydrogen. Alloy phases of composition AB2, AB3, and\\/or AB5 have been identified, most of which crystallize in the Cu2Mg, Cu3Au, Ni3Ti, Cd3Mg,

B. Erdmann; C. Keller

1973-01-01

300

Preparation and luminescence properties of lanthanide (Eu 3+, Sm 3+) complexes and their hectorite-based composites  

NASA Astrophysics Data System (ADS)

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.

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

2010-02-01

301

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

2009-12-24

302

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.

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

303

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

304

Valence calculations of lanthanide anion binding energies: a comprehensive study  

NASA Astrophysics Data System (ADS)

We have applied a methodology of universal jls restrictions on the 4f^n subgroup of relativistic configuration-interaction calculations of progressively more complex lanthanide anionsootnotetextS. M. O'Malley and D. R. Beck, Phys. Rev. A 77, 012505 (2008).^,ootnotetextS. M. O'Malley and D. R. Beck, Phys. Rev. A 78, 012510 (2008).^,ootnotetextS. M. O'Malley and D. R. Beck, Phys. Rev. A, in press.. Our completed study of the row predicts bound 6p attachments to all lanthanide ground state configurations except Yb, additional 6p attachments to excited opposite parity configurations in Tb and Lu, and 6s attachments to excited open-6s thresholds in La, Ce, Pr, and Gd. In total we predict more than 100 bound states for the lanthanide anions, and we hope this comprehensive study encourages further experimentalootnotetexte.g. V. T. Davis et al., Nucl. Instrum. Methods Phys. Res. B 241, 118 (2005).^,ootnotetexte.g. C. W. Walter et al., Phys. Rev. A 76, 052702 (2007). interest in these anions. Such measurements will be useful in ``fine tuning'' these ab initio binding energies to account for missing core-valence correlation and the approximations that were necessary in these complex calculations.

O'Malley, Steven M.; Beck, Donald R.

2009-05-01

305

Development of selective detection method for 5-formyl-2'-deoxyuridine in DNA using a fluorogenic reagent.  

PubMed

  It is important that various lesions in DNA were detected selectively and conveniently to know mechanisms of carcinogenicity and/or aging of cells. However, most detection methods of DNA lesion are complicated and take a long time for enzymatic hydrolysis and analysis by HPLC and/or mass spectrometry. This review shows the new concept for detection of DNA lesion by "fluorogenic reagent". Inspired by the unique bis-heteroaryl structure of luciferin and 5-heteroaryl-2'-deoxyuridine having good fluorescence properties, we designed and synthesized fluorogenic reagent 4,5-dimethoxy-2-aminothiophenol for a selective and convenient detection for 5-formyl-2'-deoxyuridine, which is generated in yields comparable to that of 2'-deoxy-8-oxoguanosine, in DNA. Generated 5-(5,6-dimethoxybenzothiazol-2-yl)-2'-deoxyuridine has a high quantum yield and larger Stokes shift in aqueous solution. This derivatization of 5-formyl-2'-deoxyuridine in oligodeoxynucleotide occurred quickly and quantitatively. The fluorogenic reagent was also revealed to detect 5-formyl-2'-deoxyuridine in ?-irradiated calf thymus DNA with irradiation dose dependent manner. Thus, our fluorogenic strategy enables to selective and convenient detection of lesion in DNA exposed to various forms of oxidative stress. PMID:24088348

Sato, Kousuke

2013-01-01

306

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

307

Dimethyl carbonate as a modern green reagent and solvent  

NASA Astrophysics Data System (ADS)

Published data on dimethyl carbonate as a safe reagent and solvent in organic synthesis are generalized and analyzed. The methods of dimethyl carbonate preparation and its use as methylating and carboxymethylating reagent are considered. The attention is focused on the environmentally safe processes corresponding to the green chemistry principles.

Aricò, F.; Tundo, Pietro

2010-08-01

308

Reagents in microfluidics: an 'in' and 'out' challenge.  

PubMed

Microfluidic devices are excellent at downscaling chemical and biochemical reactions and thereby can make reactions faster, better and more efficient. It is therefore understandable that we are seeing these devices being developed and used for many applications and research areas. However, microfluidic devices are more complex than test tubes or microtitre plates and the integration of reagents into them is a real challenge. This review looks at state-of-the-art methods and strategies for integrating various classes of reagents inside microfluidics and similarly surveys how reagents can be released inside microfluidics. The number of methods used for integrating and releasing reagents is surprisingly large and involves reagents in dry and liquid forms, directly-integrated reagents or reagents linked to carriers, as well as active, passive and hybrid release methods. We also made a brief excursion into the field of drug release and delivery. With this review, we hope to provide a large number of examples of integrating and releasing reagents that can be used by developers and users of microfluidics for their specific needs. PMID:23925517

Hitzbleck, Martina; Delamarche, Emmanuel

2013-08-08

309

Physically absorbable reagents-collectors in elementary flotation  

SciTech Connect

Based on the reviewed researches held at the Institute of Mining, Siberian Branch, Russian Academy of Sciences, the effect of physically absorbable reagents-collectors on formation of a flotation complex and its stability in turbulent pulp flows in flotation machines of basic types is considered. The basic requirements for physically absorbable reagents-collectors at different flotation stages are established.

S.A. Kondrat'ev; I.G. Bochkarev [Russian Academy of Sciences, Novosibirsk (Russian Federation). Institute of Mining

2007-09-15

310

Lanthanide concentrations in freshwater plants and molluscs, related to those in surface water, pore water and sediment. A case study in The Netherlands  

Microsoft Academic Search

Industrial emissions of lanthanides to aquatic ecosystems increase, but knowledge of the environmental fate of these metals is limited. Here we focus attention upon the distribution of lanthanides in freshwater ecosystems, describing lanthanide partitioning between sediment, water and biota. Since lanthanides are often used as oxidation-state analogues for actinides, their distribution can reflect long-term behaviour of the radioactive transuranics. Concentrations

Lennart Weltje; Heike Heidenreich; Wangzhao Zhu; Hubert Th. Wolterbeek; Siegfried Korhammer; Jeroen J. M. de Goeij; Bernd Markert

2002-01-01

311

Lanthanide-Sensitized Luminescence as a Promising Tool in Clinical Analysis  

Microsoft Academic Search

The recent applications and novelties of lanthanide-sensitized luminescence (LSL) as detection technique in clinical analysis are here reviewed. In LSL, lanthanide ions form complexes with organic compounds; in these complexes, the energy absorbed by the organic chromophore (usually, the analyte) at its characteristic excitation wavelength is transferred to a triplet state of the molecule and then transferred to a resonance

A. Ruiz-Medina; E. J. Llorent-Martínez; P. Ortega-Barrales; M. L. Fernández-De Córdova

2011-01-01

312

Distribution, speciation and bioavailability of Lanthanides in the Rhine-Meuse estuary, The Netherlands  

Microsoft Academic Search

Changing environmental conditions may influence the fate and bioavailability of lanthanides (part of the rare earth elements [Ln]) in estuaries. The aim of this study was to quantify the variation in estuarine lanthanide solid\\/water distribution, speciation, and bioaccumulation. The latter was studied in the amphipod Corophium volutator under field and laboratory conditions. Calculations with the chemical equilibrium model MINEQL indicate

Caroline T. A. Moermond; Jakolien Tijink; Wezel van A. P; Albert A. Koelmans

2001-01-01

313

Behavioral responses to weak electric fields and a lanthanide metal in two shark species  

Microsoft Academic Search

The unintentional catch of sharks on hooks intended for other fishes is an economic, environmental and safety concern. Recent research has sought to repel sharks from baited hooks by applying various lanthanide metals and alloys to stimulate the elasmobranch electrosensory system. We present a simplified experimental methodology to test responses of two shark species to a single lanthanide metal. Behavioral

Laura K. Jordan; John W. Mandelman; Stephen M. Kajiura

314

Lanthanide transport in stabilized zirconias: Interrelation between ionic radius and diffusion coefficient  

Microsoft Academic Search

The diffusion of all stable lanthanides was measured both in calcia stabilized zirconia (CSZ) and in yttria stabilized zirconia (YSZ) in the temperature range between 1286 and 1600 °C. The lanthanide diffusion coefficients obtained increase with increasing ionic radius. The experimental activation enthalpy of diffusion is near 6 eV for CSZ and between 4 and 5 eV for YSZ and

Martin Kilo; Marcela A. Taylor; Christos Argirusis; Günter Borchardt; Sylvain Weber; Hubert Scherrer; Robert A. Jackson

2004-01-01

315

Hot-Pressed Silicon Nitride with Various Lanthanide Oxides as Sintering Additives.  

National Technical Information Service (NTIS)

The effects of addition of various lanthanide oxides and their mixture with Y2O3 on the sintering of Si3N4 were investigated. The addition of simple and mixed lanthanide oxides promoted the densification of Si3N4 in hot-pressing at 1800 C under 300-400kg/...

K. Ueno Y. Toibana

1984-01-01

316

Hot-Pressed Silicon Nitride with Various Lanthanide Oxides as Sintering Additives.  

National Technical Information Service (NTIS)

The effects of addition of various lanthanide oxides and their mixture with Y2O3 on the sintering of Si3N4 were investigated. The addition of simple and mixed lanthanide oxides promoted the densification of Si3N4 in the hot-pressing at 1,800C under 300-40...

K. Ueno Y. Toibana

1984-01-01

317

EXTRACTION OF LIGHT LANTHANIDE NITRATES BY TRI-n-BUTYL PHOSPHATE  

Microsoft Academic Search

The distribution of La, Pr, Nd, Eu, Gd and Tb nitrates between water and tributyl phosphate was investigated over a broad range of concentrations. It has been found that the distribution constant varies only slightly with the lanthanide atomic number, whereas the activity coefficients of the salts in concentrated organic solutions change considerably with both the lanthanide atomic number and

L. Bednarczyk; S. Siekierski

1989-01-01

318

Lanthanides in metallic nuclear fuels: Their behavior and methods for their control  

NASA Astrophysics Data System (ADS)

The thermodynamic and experimental basis is given for using dopant additives to bind lanthanides as intermetallic compounds in metallic nuclear fuels. Lanthanide fission products are a major factor in limiting the lifetime of the fuel, because they migrate to the fuel slug peripheral surface where they participate in fuel-cladding chemical interactions (FCCI) with the D9 or HT9 steel cladding. Lanthanide carryover in recycled metal fuels can accelerate FCCI, as recycled lanthanides would likely segregate from the fuel phase, putting the lanthanides in prompt contact with the cladding. In out-of-pile tests, the use of palladium was examined for binding the lanthanides, with palladium selected because of its known metallurgical properties in fuel-related systems and because of its known behavior in irradiated Experimental Breeder Reactor-II (EBR-II) fuels. Initial results confirmed that palladium may be expected to mitigate FCCI arising from lanthanides, and it has been recommended for in-pile tests. Transport phenomena responsible for lanthanide migration were also evaluated, and liquid-like behaviors were identified as being dominant. Liquid-like behaviors include transport with liquid metals, liquid metal solutions, and rapid surface transport of alloys/metals near their melting temperatures. The analysis led to establishing general criteria for selecting dopant additives and identifying tin, antimony, and tellurium as alternates for further testing.

Mariani, R. D.; Porter, D. L.; O'Holleran, T. P.; Hayes, S. L.; Kennedy, J. R.

2011-12-01

319

Ceramic transactions: Synthesis and application of lanthanide-doped materials. Volume 67  

SciTech Connect

This document contains reports from the proceedings of the Synthesis and APplications of Lanthanide-Doped ceramics, Crystals, and Glasses Symposium. Topics include the role of lanthanides in optical materials; emissive materials and active waveguides; phosphors and scintillators; and optical and magneto-optical applications. Individual projects have been processed separately for the United States Department of Energy databases.

Potter, B.G. Jr.; Bruce, A.J. [eds.

1996-12-31

320

Lanthanides in Metallic Nuclear Fuels: Their Behavior and Methods for Their Control  

SciTech Connect

The thermodynamic and experimental basis is given for using dopant additives to bind lanthanides as intermetallic compounds in metallic nuclear fuels. Lanthanide fission products are a major factor in limiting the lifetime of the fuel, because they migrate to the fuel slug peripheral surface where they participate in fuel-cladding chemical interactions (FCCI) with the steel cladding. Lanthanide carryover in recycled metal fuels can accelerate FCCI, as recycled lanthanides would likely segregate from the fuel phase, putting the lanthanides in prompt contact with the cladding. In out-of-pile tests we examined the use of Pd for binding the lanthanides, with Pd selected because of its known metallurgical properties in fuel related systems and because of its known behavior in irradiated EBR-II fuels. Initial results confirmed that palladium may be expected to mitigate FCCI arising from lanthanides, and it has been recommended for in-pile tests. We also evaluated transport phenomena responsible for lanthanide migration, and identified liquid-like behaviors as being dominant. Liquid-like behaviors include transport with liquid metals, liquid metal solutions, and rapid surface transport of alloys/metals near their melting temperatures. The analysis led to establishing general criteria for selecting alternate dopant additives, and identifying Sn, Sb, and Te as alternates for further testing.

Robert D. Mariani; Douglas L. Porter; Thomas P. O'Holleran; Steven L. Hayes; J. Rory Kennedy

2011-12-01

321

Shift work, cancer and \\  

Microsoft Academic Search

This commentary intends to instigate discussions about upcoming epidemiologic research, and its interpretation, into putative links between shift work, involving circadian disruption or chronodisruption [CD], and the development of internal cancers. In 2007, the International Agency for Research on Cancer (IARC) convened an expert group to examine the carcinogenicity of shift work, inter alia characterized by light exposures at unusual

Thomas C Erren

2010-01-01

322

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

323

SPECTRAL SHIFT CONTROL REACTOR  

Microsoft Academic Search

The Spectral Shift Control Reactor is a variation of the pressurized-; water reactor. Reactivity control is accomplished by varying the concentration ; of a heavy water-water mixture in the primary loop of the reactor. The addition ; of heavy water changes the relative number of neutrons at any particular energy ; (that is, shifts the neutron spectrum), resulting in more

R. W. Deuster; Z. Levine

1961-01-01

324

Immobilized Bioluminescent Reagents in Flow Injection Analysis.  

NASA Astrophysics Data System (ADS)

Available from UMI in association with The British Library. Bioluminescent reactions exhibits two important characteristics from an analytical viewpoint; they are selective and highly sensitive. Furthermore, bioluminescent emissions are easily measured with a simple flow-through detector based on a photomultiplier tube and the rapid and reproducible mixing of sample and expensive reagent is best achieved by a flow injection manifold. The two most important bioluminescent systems are the enzyme (luciferase)/substrate (luciferin) combinations extracted from fireflies (Photinus pyralis) and marine bacteria (Virio harveyi) which requires ATP and NAD(P)H respectively as cofactors. Reactions that generate or consume these cofactors can also be coupled to the bioluminescent reaction to provide assays for a wide range of clinically important species. A flow injection manifold for the study of bioluminescent reactions is described, as are procedures for the extraction, purification and immobilization of firefly and bacterial luciferase and oxidoreductase. Results are presented for the determination of ATP using firefly system and the determination of other enzymes and substrates participating in ATP-converting reactions e.g. creatine kinase, ATP-sulphurylase, pyruvate kinase, creatine phosphate, pyrophosphate and phophoenolypyruvate. Similarly results are presented for the determination of NAD(P)H, FMN, FMNH_2 and several dehydrogenases which produce NAD(P)H and their substrates, e.g. alcohol, L-lactate, L-malate, L-glutamate, Glucose-6-phosphate and primary bile acid.

Nabi, Abdul

325

Quality requirements for critical assay reagents used in bioanalysis of therapeutic proteins: what bioanalysts should know about their reagents.  

PubMed

Ligand-binding assays are the standard technology used for bioanalysis of therapeutic proteins, for example, for drug quantification (pharmacokinetics assays) and immunogenicity testing (antidrug antibody assays). Besides the selection of the most suitable technology platform (e.g., ELISA, electrochemiluminescence assays and surface plasmon resonance assays) and assay procedure, a pivotal prerequisite for good assay performance on any technology platform is the design, production and characterization of high quality reagents. To enable bioanalytical project support over the complete product life cycle, an appropriate long-term reagent supply is needed. This perspective describes our opinion on the requirements for generation and QC of critical reagents used in ligand-binding assays for drug quantification and antidrug antibody detection to enable high-quality assays and long-term supply, including reagent batch switches. The critical parameters during reagent design, production and long-term supply, along with the appropriate analytical methods for QC testing and appropriate certification, are discussed. PMID:21388265

Staack, Roland F; Stracke, Jan O; Stubenrauch, Kay; Vogel, Rudolf; Schleypen, Julia; Papadimitriou, Apollon

2011-03-01

326

Josephson shift registers  

NASA Astrophysics Data System (ADS)

A review of Josephson shift-register circuits that have been designed, fabricated, or tested is presented with emphasis on work in the 1980s. Operating speed is most important, since it often limits system performance. Older designs used square-wave clocks, but most modern designs use offset sine waves, with either two or three phases. Operating margins and gate bias uniformity are key concerns. The fastest measured Josephson shift register operated at 2.3 GHz, which compares well with a GaAs shift register that consumes 250 times more power. The difficulties of high-speed testing have prevented many Josephson shift registers from being operated at their highest speeds. Computer simulations suggest that 30-GHz operaton is possible with current Nb/Al2O3/Nb technology. Junctions with critical current densities near 10 kA/sq cm would make 100-GHz shift registers feasible.

Przybysz, John X.

1989-08-01

327

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

2012-08-16

328

Praseodymium Nitrate and Neodymium Complexation with Organophosphorus Reagents in Supercritical Carbon Dioxide Solvent  

SciTech Connect

Complex formation reactions of praseodymium nitrate hexahydrate, and neodymium nitrate hexahydrate salts with tri-n-butyl phosphate (TBP) and several other neutral organophosphorus reagents were investigated in supercritical carbon dioxide. The concentration of the metal complexes in the supercritical fluid (SCF) phase was determined using UV-Vis and luminescence spectroscopies. The stoichiometry of the complexes was determined using the mole-ratio method. Extraction equilibrium constants were calculated from the spectral data using least-squares regression and hard-equilibria models. UV-Vis absorbance data indicate that praseodymium nitrate and neodymium nitrate both form 1:4 lanthanide–tributyl phosphate complexes in supercritical carbon dioxide at 308 K. The conditional extraction coefficients for those two systems were calculated to be log Kex=7.45±0.06 for the praseodymium system and log Kex=7.52±0.03 for the neodymium system. For comparison, neodymium nitrate complexation reactions with tri-n-butyl phosphate and tributyl phosphite (TBPO3) were studied in hexane under ambient conditions. UV-Vis data indicate that a 1:4 neodymium–tributyl phosphate complex is formed in hexane with a conditional extraction coefficient of log Kex=3.4±0.2. Tributyl phosphite forms a 1:8 complex with neodymium in hexane with a conditional extraction coefficient of log Kex=11.0±0.1. Neodymium nitrate was titrated with other organophosphorus reagents, tributyl phosphite and tributyl phosphine oxide (TBPO), in supercritical carbon dioxide to investigate differences between neutral oxygen donor ligands and neutral phosphorus donor ligands. UV-Vis and luminescence data indicate that neodymium nitrate forms a 1:8 complex with tributyl phosphite and a 1:5 complex with tributyl phosphine oxide, compared to a 1:4 complex with tri-n-butyl phosphate. The conditional extraction coefficient for the 1:8 neodymium–tributyl phosphite system was calculated as log Kex=21.4±0.2 from UV-Vis data, and log Kex=19.8±0.2 from luminescence data. The conditional extraction coefficient for the 1:5 neodymium–tributyl phosphine oxide complex was calculated as log Kex=7.83±0.05.

Robert V. Fox; R. Duane Ball; Peter de B. Harrington; Harry W. Rollins; John G. Jolley; Chien M. Wai

2004-11-01

329

IUPAC-NIST Solubility Data Series. 85. Transition and 12-14 Main Group Metals, Lanthanide, Actinide, and Ammonium Halates  

NASA Astrophysics Data System (ADS)

This paper is the fourth and final volume in the halate solubility series. The solubility data for halates of transition metals, lanthanides, actinides, ammonium, and metallic elements of the main groups 12-14 are reviewed. Where appropriate, binary, ternary, and multicomponent systems are critically evaluated. Most of the solubility results were obtained in water or aqueous solutions of electrolytes. The solubility in organic solvents and aqueous-organic solvent mixtures is also collected in this volume. All these data were critically examined for their reliability. The best values were selected on the basis of critical evaluations and presented in tabular form. Fitting equations and graphical plots are also provided. When numerical data were not reported in an original publication, they were read out from figures and digitized by the compilers. The quantities, units, and symbols used in this volume are in accord with IUPAC recommendations. We always reported the original data and, if necessary, transferred them into the IUPAC recommended units and symbols. The literature on the solubility data was researched through 2002. The halates of these metals play a role in industrial processes. For example, some halates are essential as catalysts, heat stabilizers, and blanching reagents for manufacturing polymer products such as textiles and resins. Some iodates are used in pyrotechnic compounds for weather modification and colored smoke generation. The nonlinear halate crystals are important in construction of optical devices.

Miyamoto, Hiroshi

2008-06-01

330

21 CFR 866.3332 - Reagents for detection of specific novel influenza A viruses.  

Code of Federal Regulations, 2010 CFR

...Reagents for detection of specific novel influenza A viruses. 866.3332 Section 866...Reagents for detection of specific novel influenza A viruses. (a) Identification . Reagents for detection of specific novel influenza A viruses are devices that are...

2009-04-01

331

21 CFR 866.3332 - Reagents for detection of specific novel influenza A viruses.  

Code of Federal Regulations, 2010 CFR

...Reagents for detection of specific novel influenza A viruses. 866.3332 Section 866...Reagents for detection of specific novel influenza A viruses. (a) Identification . Reagents for detection of specific novel influenza A viruses are devices that are...

2010-04-01

332

41 CFR 101-42.1102-5 - Drugs, biologicals, and reagents other than controlled substances.  

Code of Federal Regulations, 2012 CFR

...GSA. (b) Donation requirements. Surplus drugs, biologicals, and reagents...to prior approval by GSA. (1) When surplus drugs, biologicals, and reagents...by the State agency or donee. (3) Surplus drugs, biologicals, and reagents...

2012-07-01

333

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

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Streptococcus spp. exo-enzyme reagents. 866.3720 Section 866.3720 Food... Serological Reagents § 866.3720 Streptococcus spp. exo-enzyme reagents. (a) Identification....

2009-04-01

334

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... Serological Reagents § 866.3720 Streptococcus spp. exo-enzyme reagents. (a) Identification....

2010-04-01

335

Allylic substitution on cyclopentene and -hexene rings with alkynylcopper reagents.  

PubMed

Substitution of cyclic allylic picolinates with a reagent derived from TMS-C?CMgBr and a copper salt was investigated. Although the previous type of reagent (TMSC?CMgBr and CuBr·Me(2)S) developed for linear allylic picolinates was less product selective and regioselective, the Cu(acac)(2)-derived reagent was highly selective (94-95%) to afford the S(N)2' product in good yields. As an application, several C-C bond formations at the acetylenic carbon and the synthesis of the PG intermediate were studied with success. PMID:22070671

Wang, Qian; Kobayashi, Yuichi

2011-11-09

336

A series of three-dimensional architectures constructed from lanthanide-substituted polyoxometalosilicates and lanthanide cations or lanthanide-organic complexes as linkers.  

PubMed

Six 3D architectures based on lanthanide-substituted polyoxometalosilicates, KLn[(H(2)O)(6)Ln](2)[(H(2)O)(4)LnSiW(11)O(39)](2)·nH(2)O (Ln = La 1, n = 42; Ce 2, n = 40), H[(H(2)O)(6)Nd](2)[(H(2)O)(7)Nd][(H(2)O)(4)NdSiW(11)O(39)][(H(2)O)(3)NdSiW(11)O(39)]·13H(2)O (3), H(2)K(2)[(Hpic)(H(2)O)(5)Ln](2)[(H(2)O)(4)LnSiW(11)O(39)](2)·nH(2)O (Ln = La 4, n = 18.5; Ce 5, n = 35; Nd 6, n = 36; Hpic = 4-picolinic acid), have been synthesized and characterized by elemental analysis, IR and UV-vis spectroscopy, TG analysis, powder X-ray diffraction and single crystal X-ray diffraction. Compounds 1 and 2 are isostructural, built up of lanthanide-substituted polyoxoanions [{(H(2)O)(4)Ln(SiW(11)O(39))}(2)](10-) linked by Ln(3+) cations to form a 3D open framework with 1D channels. The polyoxoanion [{(H(2)O)(4)Ln(SiW(11)O(39))}(2)](10-) consists of two ?(1)-type mono-Ln-substituted Keggin anions. When Nd(3+) ion was used instead of La(3+) or Ce(3+) ions, compound 3 with a different structure was obtained, containing two kinds of polyoxoanions [{(H(2)O)(4)Nd(SiW(11)O(39))}(2)](10-) and [{(H(2)O)(3)Nd(SiW(11)O(39))}(2)](10-) which are connected together by Nd(3+) ions to yield a 3D framework. When 4-picolinic acid was added to the reaction system of 1-3, isostructural compounds 4-6 were obtained, constructed from the polyoxoanions [{(H(2)O)(4)Ln(SiW(11)O(39))}(2)](10-) linked by picolinate-chelated lanthanide centers to form a 3D channel framework. From a topological viewpoint, the 3D nets of 1, 2, 4, 5 and 6 exhibit a (3,6)-connected rutile topology, whereas the 3D structure of 3 possesses a rare (3,3,6,10)-connected topology. The magnetic properties of 2, 3, 5 and 6 have been studied by measuring their magnetic susceptibilities in the temperature range 2-300 K. PMID:22641140

An, Haiyan; Zhang, Hua; Chen, Zhaofei; Li, Yangguang; Liu, Xuan; Chen, Hao

2012-05-29

337

Synthesis and Characterization of Lanthanide Chelates with Metal Containing Ligands  

Microsoft Academic Search

Heterobimetallic complexes of La(III), Ce(III), Pr(III), Nd(III), Gd(III), Dy(III), Ho(III) and Er(III) with tetrakis(salicylidene)bis(1,3-diiminopropane) copper-(II) or zinc(II) chloride have been synthesized and characterized by spectral and molar conductance measure ments. The spectral data suggest coordination of the lanthanide ions through the phenolic oxygen and with three water molecules. All Ln(III) ions appear to be six-coordinated.Referee I: K. MoedritzerReferee II: S.

S. Tabassum; A. Bashar; F. Arjmand; K. S. Siddiqi

1997-01-01

338

Characterization of a series of lanthanide amine cage complexes  

SciTech Connect

A series of encapsulated lanthanide amine complexes (Ce, Pr, Eu, and Y) have been prepared according to a template synthesis previously described. The ligand of the complexes was 1,9-bis(2-aminoethyl)-1,4,6,9,12,14-hexaazacyclohexadecane (L). The reduction potentials of these compounds studied in propylene carbonate are reported, and the results suggest that the dibridged bis(tren) ligand (L) imparts a large stabilization to the +3 oxidation state relative to the +2 oxidation state. 29 refs., 10 figs., 11 tabs.

Smith, P.H.; Reyes, Z.E.; Lee, C.; Raymond, K.N.

1988-11-16

339

X-ray magneto-optics in lanthanides.  

PubMed

Magneto-optical methods in the visible light regime generally lack element specificity, which has become a considerable shortcoming in research on advanced heteromagnetic systems. Using circularly polarized soft x rays tuned to a 4d-4f core-level transition of a lanthanide element, the specularly reflected x-ray intensity changes proportionally to the magnetization of this element and, e.g., hystereses are easily measured element specifically. In contrast to the case of visible light, temperature dependent 4d-4f magneto-optical signals are not influenced by the thermal lattice expansion. PMID:11327984

Starke, K; Heigl, F; Vollmer, A; Weiss, M; Reichardt, G; Kaindl, G

2001-04-01

340

The low-temperature heat capacity of some lanthanide zirconates  

Microsoft Academic Search

The heat capacities of the lanthanide zirconates Gd2Zr2O7 and Eu2Zr2O7 with pyrochlore structure were measured by adiabatic calorimetry and the hybrid adiabatic relaxation method in the temperature range (0.3 to 400) K. A thermal anomaly was observed for Gd2Zr2O7 below T=15 K. From the measurements the thermodynamic functions of Gd2Zr2O7 and Eu2Zr2O7 were determined. By combining our results with the

S. Lutique; R. J. M. Konings; J.-C. Krupa; A. C. G. van Genderen; J. C. van Miltenburg; F. Wastin

2004-01-01

341

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

342

Auditory Attention Shifting.  

National Technical Information Service (NTIS)

This research effort measured the spectral and temporal dynamics of human auditory attentional control, concentrating on the requirements for efficient shifting of auditory attention within the frequency spectrum of normal human hearing.

A. Reeves B. Scharf

2008-01-01

343

Novel and cost-effective 6-plex isobaric tagging reagent, DiART, is effective for identification and relative quantification of complex protein mixtures using PQD fragmentation.  

PubMed

Deuterium isobaric Amine Reactive Tag (DiART) reagents facilitate relative quantification during proteomic analysis in a functionally similar manner to commercially available isobaric tag for relative and absolute quantitation (iTRAQ) and tandem mass tag (TMT) reagents. In contrast to iTRAQ and TMT, DiART reagents incorporate deuterium isotopes which significantly reduce the number of required synthesis steps and hence have potential to significantly reduce reagent production cost. We examined the capability of DiART for performing quantitative proteomic experiments using a linear ion-trap mass spectrometer with Pulsed Q Dissociation (PQD) fragmentation. Using a synthetic peptide tagged with DiART reagent, we observed a precise mass shift of 144.79?Da on the triply charged precursor ion, which shows complete derivatization of the N-terminus and ?-amino group of lysine. A DiART tagged tryptic digest of bovine serum albumin showed a sequence coverage of 57.99% which was very comparable to that showed by iTRAQ, 54.77%. Furthermore, a ten protein mixture tagged with DiART reagents and mixed in 1:1:1:1:1:1 exhibited?reagents and mixed in different ratios, they exhibited similar trends. We conclude that DiART reagents are capable of performing quantitative proteomic experiments using PQD on a linear ion trap mass spectrometer. Copyright © 2013 John Wiley & Sons, Ltd. PMID:24078244

Ramsubramaniam, Nikhil; Tao, Feng; Li, Shuwei; Marten, Mark R

2013-09-01

344

Shifting human color memory  

Microsoft Academic Search

Persons who witnessed an automobile accident involving a green car were exposed to information that the car was blue. On a\\u000a subsequent color recognition test, most subjects shifted their color selection in the direction of the misleading information\\u000a and away from the actual perceived color. Shifting was greater for subjects who did not initially commit themselves to a color\\u000a selection.

Elizabeth F. Loftus

1977-01-01

345

BAM Media M110: Nitrate Reduction Medium and Reagents  

Center for Food Safety and Applied Nutrition (CFSAN)

... Reagents. Culture medium. Prepare nitrate broth (M108) from nutrient broth (M114) containing 1.0 g/liter potassium nitrate. ... More results from www.fda.gov/food/foodscienceresearch/laboratorymethods

346

BAM R89: Voges-Proskauer (VP) Test Reagents  

Center for Food Safety and Applied Nutrition (CFSAN)

... To intensify and speed reaction, add a few creatine crystals to mixture. Let stand at room temperature. Read results 4 h after adding reagents. ... More results from www.fda.gov/food/foodscienceresearch/laboratorymethods

347

Characterizing fluidic seals for on-board reagent delivery  

NASA Astrophysics Data System (ADS)

The reagent delivery mechanism in a point-of-care, HIV diagnostic, microfluidic device is studied. Reagents held in an aluminum blister pack are released on the opening of a fluidic seal. The fluidic seals, controlling the flow of reagents, are characterized to reduce anomalies in the desired flow pattern. The findings of this research can be divided into three categories - 1) bonding phenomenon 2) influence of seal pattern on flow and rupture mechanics and 3) process parameters which minimize flow anomalies. Four seal patterns - line hemisphere, line flat, chevron hemisphere and chevron flat were created and tested for reagent delivery using a flow sensor and a force gauge. Experiments suggest that one of the patterns - line-flat - inducted the fewest flow anomalies. A parameter scoping exercise of the seal manufacturing process parameters (temperature, time, pressure) was performed for the line flat seal. Temperature, time, pressure / gap and distance settings which minimize flow anomalies were found.

Inamdar, Tejas; Anthony, Brian W.

2013-03-01

348

21 CFR 866.3255 - Escherichia coli serological reagents.  

Code of Federal Regulations, 2010 CFR

...reagents consist of Escherichia coli antisera conjugated with a...used to identify Escherichia coli directly from clinical...microorganism. Although Escherichia coli constitutes the greater...notification procedures in subpart E of part 807 of this chapter...

2009-04-01

349

21 CFR 866.3255 - Escherichia coli serological reagents.  

Code of Federal Regulations, 2010 CFR

...reagents consist of Escherichia coli antisera conjugated with a...used to identify Escherichia coli directly from clinical...microorganism. Although Escherichia coli constitutes the greater...notification procedures in subpart E of part 807 of this chapter...

2010-04-01

350

21 CFR 866.3255 - Escherichia coli serological reagents.  

Code of Federal Regulations, 2013 CFR

...reagents consist of Escherichia coli antisera conjugated with a...used to identify Escherichia coli directly from clinical...microorganism. Although Escherichia coli constitutes the greater...notification procedures in subpart E of part 807 of this chapter...

2013-04-01

351

Factors Affecting the Electrophilicity and Nucleophilicity of Reagents.  

National Technical Information Service (NTIS)

The apparent simplicity of the reactions of Malachite Green cation (bis-(p-dimethylaminophenyl), phenylmethyl cation) with nucleophilic reagents strongly recommends these reactions for use in the study of solvent effects on the reactivity of nucleophiles....

C. D. Ritchie

1966-01-01

352

Preparation and Development of Reagents for the Picornaviruses.  

National Technical Information Service (NTIS)

Virus stocks were prepared for 5 candidate enteroviruses. Further work with these reagents, particularly serum production, deferred pending recognition of several viruses as specific serotypes. Agent pools were prepared for coxsackievirus A9 (Grigg) and f...

H. A. Wenner

1967-01-01

353

BAM Reagents R11: Butterfield's Phosphate-Buffered Dilution ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... BAM Reagents R11: Butterfield's Phosphate-Buffered Dilution Water. ... R11 Butterfield's Phosphate-Buffered Dilution Water. KH 2 PO 4, 34 g. ... More results from www.fda.gov/food/foodscienceresearch/laboratorymethods

354

Seraclone Blood Grouping Reagent Anti-Fya ...  

Center for Biologics Evaluation and Research (CBER)

... the determination of the blood group antigens on ... Blood Grouping Reagent Anti-Fy a (Monoclonal ... Division of Communication and Consumer Affairs. ... More results from www.fda.gov/biologicsbloodvaccines/bloodbloodproducts/approvedproducts

355

21 CFR 866.3510 - Rubella virus serological reagents.  

Code of Federal Regulations, 2010 CFR

...Identification. Rubella virus serological reagents are...identify antibodies to rubella virus in serum. The identification...in the uterus with rubella virus may be born with multiple congenital...rubella syndrome). (b) Classification. Class II. The...

2009-04-01

356

21 CFR 866.3510 - Rubella virus serological reagents.  

Code of Federal Regulations, 2010 CFR

...Identification. Rubella virus serological reagents are...identify antibodies to rubella virus in serum. The identification...in the uterus with rubella virus may be born with multiple congenital...rubella syndrome). (b) Classification. Class II. The...

2010-04-01

357

Dilute Reagent Decontamination for Pressurized Water Reactors. Final Report.  

National Technical Information Service (NTIS)

The program has involved the following elements: screening studies with candidate reagents using nonradioactive autoclaved Inconel 600 and stainless steel specimens, procurement and characterization of radioactive Inconel 600 steam generator tube sections...

A. B. Johnson R. L. Clark

1984-01-01

358

21 CFR 864.1860 - Immunohistochemistry reagents and kits.  

Code of Federal Regulations, 2010 CFR

...MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Biological Stains § 864.1860 Immunohistochemistry reagents and kits. ...conventional histopathology using nonimmunologic histochemical stains, such as hematoxylin and eosin. Examples of class I...

2010-04-01

359

21 CFR 864.1860 - Immunohistochemistry reagents and kits.  

Code of Federal Regulations, 2010 CFR

...MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Biological Stains § 864.1860 Immunohistochemistry reagents and kits. ...conventional histopathology using nonimmunologic histochemical stains, such as hematoxylin and eosin. Examples of class I...

2009-04-01

360

21 CFR 864.4020 - Analyte specific reagents.  

Code of Federal Regulations, 2010 CFR

...reagents which, through specific binding or chemical reaction with substances in a specimen...identification and quantification of an individual chemical substance or ligand in biological specimens...patients and practitioners, e.g., forensic, academic, research, and other...

2009-04-01

361

21 CFR 864.4020 - Analyte specific reagents.  

Code of Federal Regulations, 2010 CFR

...reagents which, through specific binding or chemical reaction with substances in a specimen...identification and quantification of an individual chemical substance or ligand in biological specimens...patients and practitioners, e.g., forensic, academic, research, and other...

2010-04-01

362

Diagnosis of spontaneous bacterial peritonitis in children by reagent strips.  

PubMed

This study was aimed to evaluate the efficacy of dipstick tests (leukocyte esterase and nitrite) in diagnosis of spontaneous bacterial peritonitis (SBP) in cirrhotic patients. Forty six children with ascites hospitalized between 2009 and 2010 in Children Medical Center were enrolled in this study. Reagent strip assays for leukocyte esterase and nitrite were performed on ascetic fluid and the results were compared to manual cell counting and ascitic fluid culture. SBP was defined as having a polymorphonuclear ascites count of ? 250/mm3. Twenty children were female and twenty six were male with mean age of 3±3.9 years. The sensitivity specificity, positive and negative predictive values of the leukocyte esterase reagent strips were all 100%. The sensitivity, specificity, positive and negative predictive value of the nitrite reagent strip test were 100%, 97%, 90% and 100% respectively. Leukocyte esterase reagent strips may provide a rapid, bedside diagnostic test for the diagnosis of SBP. PMID:23585320

Farahmand, Fatemeh; Eshagh Roze, Mohammad; Shams, Sedighe; Ghajarzadeh, Mahsa; Mohammadi, Bahram

2013-03-16

363

21 CFR 866.3270 - Flavobacterium spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3270 Flavobacterium...these microorganisms. Most members of this genus are found in soil and water and, under certain conditions, may become...

2010-04-01

364

21 CFR 866.3270 - Flavobacterium spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3270 Flavobacterium...these microorganisms. Most members of this genus are found in soil and water and, under certain conditions, may become...

2009-04-01

365

Differentiating between trivalent lanthanides and actinides.  

PubMed

The reactions of LnCl(3) with molten boric acid result in the formation of Ln[B(4)O(6)(OH)(2)Cl] (Ln = La-Nd), Ln(4)[B(18)O(25)(OH)(13)Cl(3)] (Ln = Sm, Eu), or Ln[B(6)O(9)(OH)(3)] (Ln = Y, Eu-Lu). The reactions of AnCl(3) (An = Pu, Am, Cm) with molten boric acid under the same conditions yield Pu[B(4)O(6)(OH)(2)Cl] and Pu(2)[B(13)O(19)(OH)(5)Cl(2)(H(2)O)(3)], Am[B(9)O(13)(OH)(4)]·H(2)O, or Cm(2)[B(14)O(20)(OH)(7)(H(2)O)(2)Cl]. These compounds possess three-dimensional network structures where rare earth borate layers are joined together by BO(3) and/or BO(4) groups. There is a shift from 10-coordinate Ln(3+) and An(3+) cations with capped triangular cupola geometries for the early members of both series to 9-coordinate hula-hoop geometries for the later elements. Cm(3+) is anomalous in that it contains both 9- and 10-coordinate metal ions. Despite these materials being synthesized under identical conditions, the two series do not parallel one another. Electronic structure calculations with multireference, CASSCF, and density functional theory (DFT) methods reveal the An 5f orbitals to be localized and predominately uninvolved in bonding. For the Pu(III) borates, a Pu 6p orbital is observed with delocalized electron density on basal oxygen atoms contrasting the Am(III) and Cm(III) borates, where a basal O 2p orbital delocalizes to the An 6d orbital. The electronic structure of the Ce(III) borate is similar to the Pu(III) complexes in that the Ce 4f orbital is localized and noninteracting, but the Ce 5p orbital shows no interaction with the coordinating ligands. Natural bond orbital and natural population analyses at the DFT level illustrate distinctive larger Pu 5f atomic occupancy relative to Am and Cm 5f, as well as unique involvement and occupancy of the An 6d orbitals. PMID:22642795

Polinski, Matthew J; Grant, Daniel J; Wang, Shuao; Alekseev, Evgeny V; Cross, Justin N; Villa, Eric M; Depmeier, Wulf; Gagliardi, Laura; Albrecht-Schmitt, Thomas E

2012-06-14

366

Reversible activation of secretory phospholipase A 2 by sulfhydryl reagents  

Microsoft Academic Search

Secretory phospholipase A2s (sPLA2s) have been implicated in physiological and pathological events, but the regulatory mechanism(s) of their activities in cells remains to be solved. Previously, we reported that phenylarsine oxide (PAO), a sulfhydryl reagent, stimulated arachidonic acid (AA) release in rat pheochromocytoma PC12 cells. In this study, we examined the effects of thimerosal, another sulfhydryl reagent, to clarify the

Maiko Nabemoto; Keiko Ohsawa; Hiroyuki Nakamura; Tetsuya Hirabayashi; Takeshi Saito; Yasunobu Okuma; Yasuyuki Nomura; Toshihiko Murayama

2005-01-01

367

Development of chlorotriazine polymer dehydrocondensing reagents (Poly-Trzs)  

Microsoft Academic Search

Polymer-type dehydrocondensing reagents comprising of a triazine dehydrocondensing reagent, itself in a polymerized form (Poly-Trz—MMs'), have been developed by exploiting the chemical properties of cyanuric chloride that readily binds to alcohol or amines. A chlorotriazine polymer bearing two alkoxy substituents at the 4- and 6- positions (Poly-O-Trz–Cl) was prepared by alternating copolymerization between cyanuric chloride and tetra(ethylene glycol). Similarly, polymers

Munetaka Kunishima; Kazuyoshi Yamamoto; Kazuhito Hioki; Tomohito Kondo; Masumi Hasegawa; Shohei Tani

2007-01-01

368

Modified reagent mode in porphyry copper-molybdenum ore flotation  

Microsoft Academic Search

Test data on the selective reagent modes at bulk flotation cycle and modified carboxymethylcellulose (CMC) at a selection\\u000a cycle for the bulk copper-molybdenum concentrate. The selected reagent mode at a bulk flotation cycle with industrial kerosene\\u000a and Beraflot as collectors and OPSB as a frother made it possible to recover 87 % of copper and 82 % of molybdenum into

V. A. Bocharov; L. S. Khachatryan; V. A. Ignatkina; Zh. Baatarkhuu

2008-01-01

369

Gel-forming reagents and uses thereof for preparing microarrays  

DOEpatents

New gel-forming reagents including monomers and cross-linkers, which can be applied to gel-drop microarray manufacturing by using co-polymerization approaches are disclosed. Compositions for the preparation of co-polymerization mixtures with new gel-forming monomers and cross-linker reagents are described herein. New co-polymerization compositions and cross-linkers with variable length linker groups between unsaturated C.dbd.C bonds that participate in the formation of gel networks are disclosed.

Golova, Julia (Burr Ridge, IL); Chernov, Boris (Burr Ridge, IL); Perov, Alexander (Woodridge, IL)

2010-11-09

370

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

371

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.

Dissanayake, Prabani; Allen, Matthew J.

2009-01-01

372

Investigation of Lanthanide Sandwich Nanoclusters Encapsulated with a Cyclo-Olefin Polymer as a Gas Barrier  

NASA Astrophysics Data System (ADS)

Lanthanide nanoclusters ligated by planar organic molecules have one-dimensional sandwich structures and are air/moisture sensitive. To investigate their optical properties, originating from the lanthanide elements, for novel nanodevices, we preserved the nanoclusters with a cyclo-olefin polymer as a gas barrier. The technique enabled us to conduct various spectroscopic analyses without oxidation of the samples, such as fluorescence microscopy, photoluminescence, and X-ray absorption fine structure determination, thus revealing that lanthanide sandwich nanoclusters containing europium (Eu) atoms exhibit orange fluorescence attributed to divalent Eu2+.

Tsunemi, Eika; Tsuji, Takashi; Fukazawa, Suguru; Tsunoyama, Hironori; Watanabe, Yoshio; Nakajima, Atsushi

2012-03-01

373

Facile sonochemical synthesis and photoluminescent properties of lanthanide orthophosphate nanoparticles  

NASA Astrophysics Data System (ADS)

Uniform lanthanide orthophosphate LnPO4 (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 LnPO4 (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd) products have nanorod bundles morphology, while the tetragonal LnPO4 (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 LnPO4 (Ln=La-Gd) nanorod bundles is proposed. Eu3+-doped LaPO4 and Tb3+-doped CePO4 samples were also prepared by using the same synthetic process, which exhibit an orange-red (Eu3+:5D0-7F1, 2, 3, 4) and green (Tb3+, 5D4-7F3, 4, 5, 6) emission, respectively.

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

2009-02-01

374

Purification of lanthanides for double beta decay experiments  

NASA Astrophysics Data System (ADS)

There are several potentially double beta active isotopes among the lanthanide elements. However, even high purity grade lanthanide compounds contain 238U, 226Ra and 232,228Th 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 CeO2, Nd2O3 and Gd2O3. 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&D of the methods to remove the pollutions with improved efficiency is in progress.

Polischuk, O. G.; Barabash, A. S.; Belli, P.; Bernabei, R.; Boiko, R. S.; Cappella, F.; Cerulli, R.; Danevich, F. A.; Incicchitti, A.; Laubenstein, M.; Mokina, V. M.; Nisi, S.; Poda, D. V.; Tretyak, V. I.

2013-08-01

375

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

376

Lessons learned from dinuclear lanthanide nano-magnets.  

PubMed

The quest for higher density information storage has led to the investigation of Single-Molecule Magnets (SMMs) as potential molecules to be applied in materials such as hard discs. In order for this to occur, one must first design metal complexes which can retain magnetic information at temperatures where these applications become possible. This can only be achieved through answering and understanding fundamental questions regarding the observed physical properties of SMMs. While mononuclear lanthanide complexes have shown promise in obtaining high energy barriers for the reversal of the magnetisation they are limited to Single-Ion Magnet behaviour intrinsic to one metal centre with a limited number of unpaired electrons. As a way of increasing the effective anisotropic barrier, systems with higher nuclearity have been sought to increase the spin ground state of the molecule. Dinuclear complexes are presented as key compounds in studying and understanding the nature of magnetic interactions between metal ions. This tutorial review will span a number of dinuclear 4f complexes which have been critical in our understanding of the way in which lanthanide centres in a complex interact magnetically. It will examine key bridging moieties from the more common oxygen-based groups to newly discovered radical-based bridges and draw conclusions regarding the most effective superexchange pathways allowing the most efficient intracomplex interactions. PMID:23334210

Habib, Fatemah; Murugesu, Muralee

2013-04-21

377

Extraction of a monospecific Coombs-reagent from chicken eggs.  

PubMed

During the last ten years the extraction of specific antibodies (ab) from the yolk of eggs of immunised chickens is more and more accepted as an useful alternative to the immunisation of mammals. The subject of this work is the immunisation of chickens with human IgG and the extraction of specific anti human IgG ab from egg yolk in order to obtain monospecific Coombs reagent. 12 Leghorn hens (25 weeks old) were immunised with intact human IgG (INTACGLOBIN). The chickens were immunised with 100 microg IgG/animal once per week for a period of seven weeks. The highest titre was observed after the 5th immunisation, the following immunisations achieved no further titre increase. The IgY purification was performed according to the method of Akita and Nakai (1993). The resulting IgY preparation was tested for the presence of hetero-agglutinine by means of direct agglutination using human erythrocytes of all blood groups. Thereafter 58 blood donors were tested by means of direct or indirect Coombs-test using a reference reagent (DAKO) and a Coombs reagent isolated from chicken eggs (IgY antibodies). No differences have been found between the results obtained using both Coombs reagents. Presented results show that there is a possibility to produce Coombs-reagent in chickens. Advantages of this method are: 1) non invasive antibody sampling by egg collection instead of bleeding the animal (refinement of antibody production); 2) decreasing amount of animals necessary to produce high amounts of reagent; 3) IgY-preparation contains no hetero-agglutinine in contrast to serum ab from mammals, therefore additional step in reagent production e.g. the absorption of hetero-agglutinins is not necessary. PMID:12579352

Gutiérrez Calzado, Esteban; Cruz Mario, Eduardo; Samón Chávez, Tomás; Vázquez Luna, Ernesto; Corona Ochoa, Zelma; Schade, Rüdiger

2003-01-01

378

Magneto-photoluminescence in lanthanide-bearing endohedral metallofullerenes with various cage symmetries  

NASA Astrophysics Data System (ADS)

Taken as a family, endohedral metallofullerenes (EMF) nanomaterials provide opportunities for exquisite functional tunability at the nanoscale, enabling a wide range of synthetic nanoparticles with diverse sizes, symmetries, electronic, optical and, especially, magnetic properties. In particular, metallofullerenes incarcerating lanthanide ions will permit endohedral luminescence due to the 4f optically-active electrons being uninvolved in the stabilizing charge transfer between the endohedral guest and cage. In addition, if those lanthanide ions possess optical transitions beyond the absorption onset of the cage, a well-defined optical spectrum may be observed for the metallofullerene system. In this talk, several magneto-optical and time-resolved studies at high magnetic fields on lanthanide-based EMFs with different cage symmetries will be presented, where the residual magnetic degeneracies in the lanthanide ion energy levels are lifted and observed in the optical spectrum with magnetic field strengths in excess of 10 T.

Merritt, Travis; Dorn, Harry; Khodaparast, Giti A.; McGill, Steve

2012-02-01

379

Electrochemical and Spectroscopic Studies of Some Less Stable Oxidation States of Selected Lanthanide and Actinide Elements.  

National Technical Information Service (NTIS)

Simultaneous observation of electrochemical and spectroscopic properties (spectroelectrochemistry) at optically transparent electrodes (OTE's) was used to study some less stable oxidation states of selected lanthanide and actinide elements. Cyclic voltamm...

D. E. Hobart

1981-01-01

380

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

381

Patterns in the stability of the lower oxidation states of the actinides and lanthanides  

SciTech Connect

The authors compare the first half of the lanthanides and the second half of the actinides by considering the specifics of the electronic structure of the valence atoms of the f-, d-, and s-orbitals, consisting of he following: The lanthanides from praseodymium to europium and from dysprosium to ytterbium, as well as the actinides from californium to nobelium, have the same electronic configuration f /SUP n/ s/sub 2/ in the state of free neutral atoms, which corresponds to their divalent state. On the basis of a consideration of the energy characteristics of the valence orbitals of the elements of the lanthanide and actinide famililies and as a result of an experimental determination of the standard oxidation potential of these elements, the authors consider the profound similarity between the elements of the first half of the lanthanide family and the second half of the actinide family to be established.

Mikheev, N.B.; Auerman, L.N.; Ionova, G.V.; Korshunov, B.G.; Spitsyn, V.I.

1986-09-01

382

A microporous lanthanide-tricarboxylate framework with the potential for purification of natural gas.  

PubMed

A novel robust three-dimensional lanthanide organic framework with high thermal stability has been demonstrated to exhibit the potential for purification of natural gas in nearly pure form from an 8-component gas mixture at room temperature. PMID:23023243

He, Yabing; Xiang, Shengchang; Zhang, Zhangjing; Xiong, Shunshun; Fronczek, Frank R; Krishna, Rajamani; O'Keeffe, Michael; Chen, Banglin

2012-10-01

383

CHARACTERIZATION OF METAL BINDING SITES IN FULVIC ACIDS BY LANTHANIDE 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 luminescent properties of the tripositive lanthanide metal ions, has been developed to Selectively probe metal bindi...

384

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...

385

Enzymatic synthesis in biphasic aqueous-organic systems. II. Shift of ionic equilibria.  

PubMed

Ionic equilibria in "water-water-immiscible organic solvent" systems have been studied. It has been shown that in such systems shift of the apparent pK value of acids and bases takes place (compared to aqueous solutions), the value of the shift being rather high, up to 5 and more pH units (with 2,4-dinitrophenyltryptophan as an acid and neutral red as a base). The pK shift of ionogenic reagents observed in biphasic systems can be used in preparative organic synthesis for increasing the yield of end products in enzyme-catalyzed reactions. In connection with this, the physico-chemical reasons for the equilibrium shift in a chemical reaction that involves one or two ionogenic reagents are theoretically analyzed. The above approach has been tested with two alpha-chymotrypsin-catalyzed reactions, i.e., synthesis of N-benzoyl-L-phenylalanine ethyl ester (from NBz-LPhe-OH and ethanol) and synthesis of N-acetyl-L-tryptophanyl-L-leucine amide (from NAc-LTrp-OH and LLeu-NH2). In water the equilibria in these reactions are shifted almost entirely towards the starting reagents with the yield of end product being negligibly low. In biphasic systems consisting of chloroform +5% (v/v) water or ethyl acetate +2% (v/v) water, the yield of both the ester and the dipeptide reaches 100%. PMID:7213763

Martinek, K; Semenov, A N

1981-03-13

386

Luminol-type chemiluminescence derivatization reagents for liquid chromatography and capillary electrophoresis  

Microsoft Academic Search

The present paper provides the principles for chemiluminescence of luminol-type compounds and their wide and powerful application to the detection system in liquid chromatography and capillary electrophoresis as derivatization reagents. The reagents can be classified into two types, chemiluminescence labeling and chemiluminogenic reagents. The former reagents are highly chemiluminescent themselves and used for tagging their intense chemiluminophores to analytes, whereas

Masatoshi Yamaguchi; Hideyuki Yoshida; Hitoshi Nohta

2002-01-01

387

Solid-liquid separation of oxidized americium from fission product lanthanides  

Microsoft Academic Search

The separation of americium from the lanthanides and curium is a requirement if transmutation of americium is to be performed in advanced nuclear fuel cycles. Oxidation of Am3+ to AmO2+ or AmO22+ may allow separation of Am from Ln and Cm in one step, since the lanthanides and curium do not have higher oxidation states as accessible. Two possible solid-liquid

T C Shehee; L R Martin; K L Nash

2010-01-01

388

Extraction of lanthanides from acidic solution using tributyl phosphate modified supercritical carbon dioxide  

Microsoft Academic Search

The feasibility of using supercritical carbon dioxide as a substitute extraction solvent in nuclear reprocessing was tested by the extraction of lanthanide ions from acidic solution. Lanthanides were extracted from 6 M HNO[sub 3]-3 M LiNO[sub 3] solutions using tributyl phosphate- (TBP-) modified CO[sub 2]. Synergistic effects were also investigated using a combination of thenoyltrifluoroacetone (TTA) and TBP-modified CO[sub 2

K. E. Laintz; E. Tachikawa

1994-01-01

389

Principles of responsive lanthanide-based luminescent probes for cellular imaging  

Microsoft Academic Search

The advent of chemical tools for cellular imaging—from organic dyes to green fluorescent proteins—has revolutionized the fields\\u000a of molecular biology and biochemistry. Lanthanide-based probes are a new player in this area, as the last decade has seen\\u000a the emergence of the first responsive luminescent lanthanide probes specifically intended for imaging cellular processes.\\u000a The potential of these probes is still undervalued

Aurore Thibon; Valérie C. Pierre

2009-01-01

390

SEPARATION OF EUROPIUM FROM OTHER LANTHANIDE RAE EARTHS BY SOLVENT EXTRACTION  

DOEpatents

This patent deals with a process of separating europium from other lanthanides present in aqueous hydrochloric or sulfuric acid solutions. The europium is selectively reduced to the divalent state with a divalent chromium salt formed in situ from chromium(III) salt plus zinc amalgam. The other trivalent lanthanides are then extracted away from the divalent europium with a nitrogen-flushed phosphoric acid ester or a phosphonic acid ester. (AEC)

Peppard, D.F.; Horwitz, E.P.; Mason, G.W.

1963-02-12

391

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

392

EXTRACTION OF LANTHANIDE ELEMENTS BY THERMOSENSITIVE POLYMER GEL COPOLYMERIZED WITH ACIDIC PHOSPHORUS COMPOUND  

Microsoft Academic Search

The extraction of lanthanide ion between an aqueous solution and a thermosensitive polymer gel, N-isopropylaciylamide (NIPA) gels copolymerized with 2-methaciyloyl-oxyethylacidphosphate (MR), was studied. This polymer gel shows a phase transition phenomena. The phase transition involves the structural change of the gel from swelling to shrinking with increasing temperature. The extraction equilibrium of lanthanide ions, La(III) and Sm(III), in an aqueous

KENJI TAKESHITA; YOSHIO NAKANO

2000-01-01

393

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

394

Style shifting in commercials  

Microsoft Academic Search

This paper presents a quantitative analysis of style shifting in a corpus of Flemish radio and television commercials. Previous research draws attention to styling processes in advertising language, as discursive actions indexing social meanings. It will be shown that the exploitation of different stylistic varieties in our corpus can be analyzed along the same lines. The analysis presented here focuses

Sofie Van Gijsel; Dirk Speelman; Dirk Geeraerts

2008-01-01

395

The shift in windpower  

Microsoft Academic Search

Despite new production records, the near-term market for new windpower projects in the US remains bleak. Congressional incentives and project proposals in the mid-1990s offer promise, but for now most development has shifted to Europe. During 1992 and 1993 the largest wind projects developed by US companies will not be in the US, but in the United Kingdom and Spain.

Gipe

1992-01-01

396

Leachability of decontamination reagents from cement waste forms  

SciTech Connect

Brookhaven National Laboratory, in order to provide technical information needed by the US Nuclear Regulatory Commission to evaluate the adequacy of near-surface disposal of decontamination wstes, has begun to study the leachability of organic reagents from solidified simulated decontamination wastes. Laboratory-scale cement waste forms containing EDTA, picolinic acid or simulated LOMI decontamination reagent were leach tested. Samples containing an organic reagent on either mixed bed ion-exchange resins or anion exchange resins were tested. A fixed interval leach procedure was used, as well as the standard procedure ANS 16.1. The leachability indices measured for the release of the acid from resin/cement composites are: 10.1 for EDTA on mixed bed resins; 9.1 for picolinic acid on mixed bed resins; 9.2 for picolinic acid on anion exchange resins; 8.8 for picolinic acid in forms containing simulated low oxidation metallic ion (LOMI) reagent on mixed bed resins and 8.7 for picolinic acid in forms containing simulated LOMI reagent on anion exchange resins. The leachability indices measured varied with leach time and the data indicate that the release mechanism may not be simply diffusion controlled. 5 references, 2 tables.

Piciulo, P.L.; Davis, M.S.; Adams, J.W.

1984-11-26

397

Separation and direct UV detection of lanthanides complexed with cupferron by capillary electrophoresis.  

PubMed

Separation and detection of lanthanides by capillary zone electrophoresis in the presence of cupferron (N-nitroso-N-phenylhydroxylamine) as UV absorbing complexing agent were investigated. The resolution of partially complexed positively charged cupferron complexes is improved by using a buffer ligand competing with cupferron for metal ions. When hydroxyisobutyric acid (HIBA) is used as buffer and competing ligand, it provides complete separation of all 14 lanthanides with good peak shapes. An on-column separation of 14 lanthanides was achieved in only 7 min using 0.1 mmol/l cupferron, 15 mmol/1 HIBA at pH 4.9. The separation efficiencies for the optimum separation condition are between 77,000 and 208,000 theoretical plates. Determination of lanthanide complexes was performed by direct UV detection at 210 nm. Detection limits (signal-to-noise ratio=3) are ca. 0.24-0.47 microg/ml for lanthanides. Under optimum conditions, the complete separation of thorium and uranium from mixed lanthanides was achieved. PMID:11105870

Oztekin, N; Erim, F B

2000-10-20

398

Supercritical fluid extraction of lanthanides with fluorinated [beta]diketones and tributyl phosphate  

SciTech Connect

Trivalent lanthanide ions (La[sup 3+], Eu[sup 3+], and Lu[sup 3+]) in solid materials can be effectively extracted by methanol-modified carbon dioxide containing a suitable fluorinated [beta]-diketone (such as HFA, TTA, or FOD) at 60[degree]C and 150 atm. Addition of a small amount of water to the solid samples can significantly increase the extraction efficiency. Tributyl phosphate (TBP) shows a strong positive synergistic effect with the fluorinated [beta]-diketones for the extraction of the lanthanides in supercritical CO[sub 2] without methanol modifier. Quantitative extraction of the lanthanides (92-98%) from sand or a cellulose-based solid material can be achieved using a mixture of TBP and one of the fluorinated [beta]-diketones in neat CO[sub 2] at 60[degree]C and 150 atm. The synergistic effect depends on the structure and fluorine substitution in the [beta]-diketone. In soil matrix, TBP+HFA are more effective than TBP+TTA or TBP+FOD for lanthanide extraction in supercritical CO[sub 2]. Without fluorine substitution, as in the case of acetylacetone, the positive synergistic extraction of lanthanides with TBP is negligible. With the mixed-ligand approach, high efficiencies of lanthanide extraction from aqueous solutions by neat CO[sub 2] can also be accomplished. 14 refs., 4 tabs.

Lin, Y.; Wai, C.M. (Univ. of Idaho, Moscow, ID (United States))

1994-07-01

399

Electron transfer in reactions of ketones with organolithium reagents. A carbon-14 kinetic isotope effect probe  

SciTech Connect

Kinetic isotope effects have been determined for reactions of ketones labeled with carbon-14 at the carbonyl carbon with MeLi and Me/sub 2/CuLi in diethyl ether at 0/sup 0/C. Observed isotope effects were as follows: (C/sub 6/H/sub 5/)/sub 2/C double bonds O + MeLi, /sup 12/k//sup 14/k = 1.000 +/- 0.002; (C/sub 6/H/sub 5/)/sub 2/C double bonds O + Me/sub 2/CuLi, 1.029 +/- 0.005; 2,4,6-Me/sub 3/C/sub 6/H/sub 2/COC/sub 6/H/sub 5/ + MeLi, 1.023 +/- 0.004. The relative reactivities of ortho-, meta-, and para-substituted benzophenones with these reagents were also determined by the competition experiments. These results are consistent with an electron-transfer step which is followed by a carbon-carbon bond-forming step that is or is not rate determining depending on the structure of ketones and reagents. The reaction of benzophenone with MeLi proceeds via rate-determining electron transfer; the change in nucleophile from MeLi to Me/sub 2/CuLi shifts the rate-determining step from electron transfer to recombination; the change in ketone from benzophenone to 2,4,6-trimethylbenzophenone also shifts the rate-determining step from electron transfer to recombination because the latter step becomes slower for the more hindered ketone. The extent of the geometrical change of the substrate at the electron-transfer transition state of the reaction of benzophenone with MeLi was estimated to be small on the basis of the magnitude of the KIE and the rho value of the Hammett correlation.

Yamataka, H.; Fujimura, N.; Kawafuji, Y.; Hanafusa, T.

1987-07-08

400

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

2013-01-18

401

Spin orbital effect in lanthanides doped silicon cage clusters  

NASA Astrophysics Data System (ADS)

The stability of lanthanides (Ln) doped silicon cage clusters Ln@Si16 has been proved by theoretical investigations. Particularly, fullerene-like Ln@Si16 structures are always more stable than Frank-Kasper structures, which is different from transition metal doped Si16 clusters. By taking into account the spin-orbital coupling (SOC), some of the Ln@Si16 clusters maintain large total magnetic moments. The clusters with Pr, Nd, Sm and Tm have large orbital moments. We have provided the evidence to clarify the importance of the spin-orbital effect in Ln doped clusters, which may give useful information for further Stern-Gerlach magnetic deflection experiments and theoretical simulations.

Guo, Lingju; Zheng, Xiaohong; Zeng, Z.; Zhang, Chao

2012-10-01

402

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

403

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.

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

404

Change of Diffusion Mechanism with Lattice Parameter in the Series of Lanthanide Indides Having L1{sub 2} Structure  

SciTech Connect

Using perturbed angular correlation spectroscopy, jump frequencies of Cd tracer atoms were measured for 12 indides In{sub 3}B (B=rare earth) in paired samples having compositions at each of the opposing phase boundaries. Jump frequencies in heavy lanthanide indides were observed to be smaller for In-richer compositions than for In-poorer compositions, but greater in the light lanthanide indides. These findings signal an unmistakable change in diffusion mechanism from the simple In-sublattice vacancy mechanism for heavy lanthanides to a B-vacancy mechanism for light lanthanides.

Collins, Gary S.; Jiang, Xia; Bevington, John P.; Selim, Farida; Zacate, Matthew O. [Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164 (United States); Department of Physics, Northern Kentucky University, Highland Heights, Kentucky 41099 (United States)

2009-04-17

405

Supported oligomethionine sulfoxide and Ellman's reagent for cysteine bridges formation.  

PubMed

A large number of bioactive peptides are cyclized through a disulfide bridge. This structural feature is very important for both bioactivity and stability. The oxidation of cysteine side chains is challenging not only to avoid intermolecular reaction leading to oligomers and oxidation of other residues but also to remove solvents and oxidant such as dimethyl sulfoxide. Supported reagents advantageously simplify the work-up of such disulfide bond formation, but may lead to a significant decrease in yield of the oxidized product. In this study, two resins working through different mechanisms were evaluated: Clear-Ox, a supported version of Ellman's reagent and Oxyfold, consisting in a series of oxidized methionine residues. The choice of the supported reagent is discussed on the light of reaction speed, side-products formation and yield considerations. PMID:22968665

Ronga, Luisa; Verdié, Pascal; Sanchez, Pierre; Enjabal, Christine; Maurras, Amélie; Jullian, Magalie; Puget, Karine; Martinez, Jean; Subra, Gilles

2012-09-12

406

Lanthanides as NMR probes of fast molecular dynamics at high magnetic fields and temperature sensors: conformational interconversion of erbium ethylenediaminetetraacetate complexes.  

PubMed

(1)H NMR measurements are reported for D2O solutions of paramagnetic complex [Er(H2O)(EDTA(4-))](-) (I) for temperature interval 273-319 K. Diamagnetic complex [Lu(H2O)(EDTA(4-))](-) (II) was used as an NMR reference compound. The spectra obtained have been analyzed using a band-shape analysis technique in the framework of dynamic NMR (DNMR) taking into account the temperature dependence of lanthanide-induced shifts. Intramolecular dynamics in I was assigned to the interconversion of ?-?E-???? and ?-?E-???? conformers with estimated activation free energy ?G(‡)(298 K) = 50 ± 4 kJ/mol. The methodology of paramagnetic 4f-element probe applications on the example of Er(3+) for the study of free-energy changes in chemical exchange processes, as well as the advantages of this method in comparison with DNMR studies of diamagnetic substances, is discussed. In accordance with the literature reviewed, the fulfilled experimental study is the first example of intramolecular dynamics determination for erbium complexes. An additional advantage of the investigation is in the approach proposed which extends the range of measurement of the NMR rate constants for paramagnetic 4f-element complexes compared to diamagnetic ones. Coordination compounds investigated represent a new type of thermometric NMR sensors and lanthanide paramagnetic probes for in situ temperature control in solutions. PMID:23587055

Babailov, Sergey P; Stabnikov, Pavel A; Zapolotsky, Eugeny N; Kokovkin, Vasily V

2013-04-15

407

Temporally and spectrally resolved imaging microscopy of lanthanide chelates.  

PubMed Central

The combination of temporal and spectral resolution in fluorescence microscopy based on long-lived luminescent labels offers a dramatic increase in contrast and probe selectivity due to the suppression of scattered light and short-lived autofluorescence. We describe various configurations of a fluorescence microscope integrating spectral and microsecond temporal resolution with conventional digital imaging based on CCD cameras. The high-power, broad spectral distribution and microsecond time resolution provided by microsecond xenon flashlamps offers increased luminosity with recently developed fluorophores with lifetimes in the submicrosecond to microsecond range. On the detection side, a gated microchannel plate intensifier provides the required time resolution and amplification of the signal. Spectral resolution is achieved with a dual grating stigmatic spectrograph and has been applied to the analysis of luminescent markers of cytochemical specimens in situ and of very small volume elements in microchambers. The additional introduction of polarization optics enables the determination of emission polarization; this parameter reflects molecular orientation and rotational mobility and, consequently, the nature of the microenvironment. The dual spectral and temporal resolution modes of acquisition complemented by a posteriori image analysis gated on the spatial, spectral, and temporal dimensions lead to a very flexible and versatile tool. We have used a newly developed lanthanide chelate, Eu-DTPA-cs124, to demonstrate these capabilities. Such compounds are good labels for time-resolved imaging microscopy and for the estimation of molecular proximity in the microscope by fluorescence (luminescence) resonance energy transfer and of molecular rotation via fluorescence depolarization. We describe the spectral distribution, polarization states, and excited-state lifetimes of the lanthanide chelate crystals imaged in the microscope.

Vereb, G; Jares-Erijman, E; Selvin, P R; Jovin, T M

1998-01-01

408

Viability Reagent, PrestoBlue, in Comparison with Other Available Reagents, Utilized in Cytotoxicity and Antimicrobial Assays.  

PubMed

This study compared different commercially available viability reagents. The growth indicator reagents include p-iodonitrotetrazolium violet (INT), PrestoBlue, and Alamar Blue which were used for antimicrobial analysis against Streptococcus mutans, Prevotella intermedia, Propionibacterium acnes, and Mycobacterium tuberculosis. PrestoBlue and Alamar Blue are resazurin based reagents that resulted in a quick and easily distinguishable colour change that allowed for visual readings. INT and Sodium 3'-[1-(phenyl amino-carbonyl)-3,4-tetrazolium]-bis-[4-methoxy-6-nitro] benzene sulfonic acid hydrate (XTT) are tetrazolium based reagents which are converted to a formazan dye in the presence of metabolically active mitochondria enzyme. For cell viability analysis, reagents XTT and PrestoBlue were compared. PrestoBlue was able to clearly indicate the minimum inhibitory concentration (MIC) of various positive drug controls on various microbial strains. PrestoBlue was also a good indicator of the 50% inhibitory concentration (IC50) of positive drug controls on various cell lines. PMID:23653650

Lall, Namrita; Henley-Smith, Cynthia Joan; De Canha, Marco Nuno; Oosthuizen, Carel Basson; Berrington, Danielle

2013-04-04

409

Regime Shift in Antitrust  

Microsoft Academic Search

This paper empirically models the longer-run deep-seated shift in intellectual thinking that followed the Chicago School’s criticism of the older antitrust doctrine, the shorter-run driving forces related to switches of the political party in power, merger waves, changes in economic activity and the level of funding and quantifies their impact on enforcement by the Antitrust Division of the U.S. Department

Vivek Ghosal

2007-01-01

410

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

2010-02-25

411

New class of Preyssler-lanthanide complexes with modified and extended structures tuned by the lanthanide contraction effect.  

PubMed

A family of polyoxometalate compounds based on Preyssler anions and lanthanide cations, K(5)Na(5)[{Pr(4)(H(2)O)(12)(pydc)(4)}{Na(H(2)O)P(5)W(30)O(110)}]·46H(2)O (1, H(2)pydc = pyridine-2,6-dicarboxylic acid), Na(7)[{Pr(4)(H(2)O)(20)(pydc)(2)(Ac)}{Na(H(2)O)P(5)W(30)O(110)}]·23H(2)O (2), and Na(10)H(2) [{Ln(2)(H(2)O)(10)(pydc)(2)}{Na(H(2)O)P(5)W(30)O(110)}]·XH(2)O (Ln = Sm 3, Eu 4, Gd 5; X = 11 for 3 and 5, 13 for 4), have been synthesized and characterized by elemental analysis and single crystal X-ray diffraction. Compound 1 exhibits a two-dimensional honeycomb layer which is built up from unique {Pr(4)} metallacycles and Preyssler anions. Remarkably, the strong involvement of the sodium countercations leads to the formation of a unique three-dimensional open architecture with one-dimensional channels. The 2D grid layer of compound 2 is constructed by the longest currently known rare-earth metal clusters {Pr(8)} and Preyssler anions. Isostructural compounds 3, 4, and 5, obtained by introduction of the intermediate lanthanide ions into the above reaction system, exhibit bisupporting [{Ln(2)(H(2)O)(10)(pydc)(2)}{Na(H(2)O)P(5)W(30)O(110)}](12-) polyoxometalate cluster structures. The magnetic properties of compounds 1 and 2 and the luminescent properties of compounds 3 and 4 are discussed in this paper. PMID:22214929

Qin, Chao; Song, Xue-Zhi; Su, Sheng-Qun; Dang, Song; Feng, Jing; Song, Shu-Yan; Hao, Zhao-Min; Zhang, Hong-Jie

2012-01-03

412

Lanthanides inhibit adipogenesis with promotion of cell proliferation in 3T3-L1 preadipocytes.  

PubMed

Lanthanides are widely used in various fields for industrial, agricultural and medical purposes. They have also been used in Chinese agriculture either as fertilizers in plant production or as performance-enhancers in animal nutrition for many years. In view of their possible application for growth enhancing purposes and new medical applications, detailed information on how lanthanides influence physiological processes in biological systems is indispensable. In the present work, the effects of lanthanides (LaCl3, CeCl3 and GdCl3) on cell proliferation and adipogenesis in 3T3-L1 preadipocytes were evaluated. The results demonstrate that lanthanides inhibit adipogenesis in 3T3-L1 preadipocytes, evidenced by decreased triglyceride content and expression of C/EBP? and PPAR?. Simultaneously, the results show that lanthanides can promote cell proliferation during the different stages of differentiation. Firstly, prior to the addition of differentiation inducers (MDI), all the three types of lanthanides resulted in a significant increase of cell growth. Secondly, during the mitotic clonal expansion (MCE) process, GdCl3, as a representative compound, is able to promote cell-cycle entry into the S phase and levels of cell cycle-regulating proteins. Third, at the late stage of the terminal differentiation, on day 8, in the presence of GdCl3, cells exhibited higher levels of G1/S regulatory proteins and proliferating cell nuclear antigen (PCNA). In addition, GdCl3 caused stronger sustained ERK activation during the differentiation process of 3T3-L1 cells. The present study demonstrates that lanthanides may modulate lipid metabolism by inhibition of adipocyte differentiation. The sustained activation of the ERK pathway might be responsible for their inhibition of differentiation and a possible link between their pro-proliferative ability and inhibition of the differentiation process is indicated. PMID:23612852

Hou, Cong-Cong; Feng, Min; Wang, Kui; Yang, Xiao-Gai

2013-06-01

413

Aptamers as therapeutic and diagnostic reagents: problems and prospects  

Microsoft Academic Search

Aptamers are nucleic acid molecules that bind specific ligands. Barriers to the application of aptamers as therapeutic and diagnostic reagents have been overcome in the past several years. In particular, aptamers that bind biomedically relevant targets have proven to be efficacious at modifying cellular metabolism. Such aptamers can be stabilized by chemical modifications and potentially used in vivo. Researchers have

Scott E Osborne; Ichiro Matsumura; Andrew D Ellington

1997-01-01

414

The Clinical Proteomic Technologies for Cancer | Reagent Opportunities  

Cancer.gov

In efforts to provide an open data platform for affinity reagents NCI’s Antibody Characterization Program has begun to utilize Material Cooperative Research and Development Agreements (M-CRADAs) through SAIC-Frederick, Inc so that commercial vendors can use the antibody characterization pipeline.

415

Synthesis and applications of heterobifunctional photocleavable cross-linking reagents.  

PubMed

This study designed, synthesized, and characterized a number of new heterobifunctional photocleavable cross-linking reagents that may be used to photomodulate the activity of proteins or to prepare caged fluorescent dyes. Biomolecules or fluorophores caged via a thiol group with the BNBASE reagent can be covalently linked to a second protein, ligand, or derivatized surface through the activated carboxyl group. Members of the new class of photocleavable cross-linking reagent can be used to cage amino groups in the molecule of interest, which can then be covalently linked to a second molecule through the thiol-reactive oxirane group. These crosslinking reagents may be used for the following applications: (1) to cage the activity of a protein by masking its active site with a second macromolecule, e.g., aminodextran; (2) to prepare a protein conjugate exhibiting an enhanced or new activity that is lost on irradiation with near-ultraviolet light, e.g., cross-linked actin dimer; (3) to target the caged compound to a specific site by cross linking to a specific antibody; (4) to attach the caged compound to a thiol or amino derivatized surface; and (5) to render the caged compound fluorescent in order to image or to quantify the yield of the photoactivation reaction. PMID:9661150

Marriott, G; Ottl, J

1998-01-01

416

Methods and reagents. Glowing blue gels and nuked nucleases.  

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 some unidentified blue fluorescence observed emanating from agarose gels, and the use of microwave ovens for DNA restriction digests. For details on how to partake in the newsgroup, see the accompanying box. PMID:7846770

Hengen, P N

1994-12-01

417

[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

418

Electrochemical generation of the Fenton's reagent: application to atrazine degradation  

Microsoft Academic Search

The degradation of refractory chemicals in water requires chemical oxidation by hydroxyl radicals. Among the systems that may be used to generate OHo, the Fenton's reagent consists of the mixing of ferrous iron and hydrogen peroxide. Even though this system is very simple, the oxidation of an organic compound is difficult to control and the ferrous iron regeneration is limited.

A Ventura; G Jacquet; A Bermond; V Camel

2002-01-01

419

Fluorescent PET(Photoinduced Electron Transfer) reagents for thiols  

Microsoft Academic Search

Michael addition of thiois to an electron deficient alkene functional group in reagents (1)-(3) give rise to fluorescence quantum yield enhancements. In the absence of the thiol, photoinduced electron transfer (PET) takes place from the fluorophore to the alkene moiety. Such electron transfer is suppressed after the thiol reaction.

A. Prasanna de Silva; H. Q. Nimal Gunaratne; Thorfinnur Gunnlaugsson

1998-01-01

420

Photonic reagent control of dynamically homologous quantum systems  

SciTech Connect

The general objective of quantum control is the manipulation of atomic scale physical and chemical phenomena through the application of external control fields. These tailored fields, or photonic reagents, exhibit systematic properties analogous to those of ordinary laboratory reagents. This analogous behavior is explored further here by considering the controlled response of a family of homologous quantum systems to a single common photonic reagent. A level set of dynamically homologous quantum systems is defined as the family that produces the same value(s) for a target physical observable(s) when controlled by a common photonic reagent. This paper investigates the scope of homologous quantum system control using the level set exploration technique (L-SET). L-SET enables the identification of continuous families of dynamically homologous quantum systems. Each quantum system is specified by a point in a hypercube whose edges are labeled by Hamiltonian matrix elements. Numerical examples are presented with simple finite level systems to illustrate the L-SET concepts. Both connected and disconnected families of dynamically homologous systems are shown to exist.

Beltrani, Vincent; Dominy, Jason; Ho, Tak-San; Rabitz, Herschel [Department of Chemistry, Frick Laboratory, Princeton University, Princeton, New Jersey 08544 (United States); Program in Applied and Computational Mathematics, Princeton University, Princeton, New Jersey 08544 (United States); Department of Chemistry, Frick Laboratory, Princeton University, Princeton, New Jersey 08544 (United States)

2007-03-07

421

Cellulose extraction from orange peel using sulfite digestion reagents  

Microsoft Academic Search

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

Ioan Bicu; Fanica Mustata

2011-01-01

422

The Hendrickson reagent and the Mitsunobu reaction: a mechanistic study.  

PubMed

The alkoxytriphenylphosphonium ion intermediate of the Mitsunobu reaction can be generated using the Hendrickson reagent, triphenylphosphonium anhydride trifluoromethanesulfonate, 1. Strangely, while the reagent 1 can be used in place of the Mitsunobu reagents (triphenylphosphine and a dialkylazodicarboxylate) for the esterification of primary alcohols, secondary alcohols such as menthol undergo elimination. Evidence is presented to show that this unexpected result is due to the presence of trialkylammonium triflate salts. Such salts lead to a dramatic decrease in the rate of esterification relative to competing elimination. The Mitsunobu esterification of menthol with p-nitrobenzoic acid was re-examined and the occurrence of elimination reported for the first time. The presence of traces of tetrabutylammonium triflate led to a dramatic reduction in the yield of inverted ester and a corresponding increase in the yield of anti elimination product 2-menthene. The mechanism of the Mitsunobu reaction is discussed in the light of the dramatic salt effect on both the rate and outcome of the reaction and the possible involvement of ion pair clustering. In contrast, use of the reagent 1 resulted in syn elimination to give a 1:2 mixture of 2- and 3-menthenes. Finally, 1 and sodium azide can be used to convert a primary alcohol into an azide in high yield. There was no reaction under Mitsunobu conditions. PMID:12968348

Elson, Kathryn E; Jenkins, Ian D; Loughlin, Wendy A

2003-08-21

423

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

424

Effect from the number of cells, pH and lanthanide concentration on the sorption of promethium on the gram negative bacterium (Shewanella putrefaciens).  

National Technical Information Service (NTIS)

The aim of this work was to investigate the sorption of the lanthanide promethium on bacteria and the distribution ratio, K(sub d), of the lanthanide between bacteria and water at different cell numbers, pH and lanthanide concentrations. There was a negat...

K. Pedersen Y. Albinsson

1990-01-01

425

Effect of lanthanide contraction on the mixed polyamine systems Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien): Syntheses and characterizations of lanthanide complexes with a tetraelenidoantimonate ligand  

NASA Astrophysics Data System (ADS)

Mixed polyamine systems Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien) (Ln=lanthanide, en=ethylenediamine, dien=diethylenetriamine, trien=triethylenetetramine) were investigated under solvothermal conditions, and novel mixed-coordinated lanthanide(III) complexes [Ln(en)2(dien)(?2-SbSe4)] (Ln=Ce(1a), Nd(1b)), [Ln(en)2(dien)(SbSe4)] (Ln=Sm(2a), Gd(2b), Dy(2c)), [Ln(en)(trien)(?-?1,?2-SbSe4)]? (Ln=Ce(3a), Nd(3b)) and [Sm(en)(trien)(?2-SbSe4)] (4a) were prepared. Two structural types of lanthanide selenidoantimonates were obtained across the lanthanide series in both en+dien and en+trien systems. The tetrahedral anion [SbSe4]3- acts as a monodentate ligand mono-SbSe4, a bidentate chelating ligand ?2-SbSe4 or a tridentate bridging ligand ?-?1,?2-SbSe4 to the lanthanide(III) center depending on the Ln3+ ions and the mixed ethylene polyamines, indicating the effect of lanthanide contraction on the structures of the lanthanide(III) selenidoantimonates. The lanthanide selenidoantimonates exhibit semiconducting properties with Eg between 2.08 and 2.51 eV.

Zhao, Jing; Liang, Jingjing; Pan, Yingli; Zhang, Yong; Jia, Dingxian

2011-06-01

426

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

427

Lanthanide-based oxides and silicates for high-kappa gate dielectric applications  

NASA Astrophysics Data System (ADS)

The ability to improve performance of the high-end metal oxide semiconductor field effect transistor (MOSFET) is highly reliant on the dimensional scaling of such a device. In scaling, a decrease in dielectric thickness results in high current leakage between the electrode and the substrate by way of direct tunneling through the gate dielectric. Observation of a high leakage current when the standard gate dielectric, SiO2, is decreased below a thickness of 1.5 nm requires engineering of a replacement dielectric that is much more scalable. This high-kappa dielectric allows for a physically thicker oxide, reducing leakage current. Integration of select lanthanide-based oxides and silicates, in particular lanthanum oxide and silicate, into MOS gate stack devices is examined. The quality of the high-kappa dielectrics is monitored electrically to determine properties such as equivalent oxide thickness, leakage current density and defect densities. In addition, analytical characterization of the dielectric and the gate stack is provided to examine the materialistic significance to the change of the electrical properties of the devices. In this work, lanthanum oxide films have been deposited by thermal evaporation on to a pre-grown chemical oxide layer on silicon. It is observed that the SiO2 interfacial layer can be consumed by a low-temperature reaction with lanthanum oxide to produce a high-quality silicate. This is opposed to depositing lanthanum oxide directly on silicon, which can possibly favor silicide formation. The importance of oxygen regulation in the surrounding environment of the La2O3-SiO2 reaction-anneal is observed. By controlling the oxygen available during the reaction, SiO2 growth can be limited to achieve high stoichiometric ratios of La2O 3 to SiO2. As a result, MOS devices with an equivalent oxide thickness (EOT) of 5 A and a leakage current density of 5.0 A/cm 2 are attained. This data equals the best value achieved in this field and is a substantial improvement over SiO(N) dielectrics, allowing for increased device scaling. High-temperature processing, consistent with the source/drain activation anneal in MOSFET processing, is performed on lanthanum-silicate based MOS devices with Ta or TaN gate electrodes and a W metal capping layer. The thermal limit of Ta is observed to be less than 800°C, resulting in a phase transformation that can result in uncontrolled shifting of the MOS device flat-band voltage. TaN is observed to be more thermally stable (up to 1000°C) and results in an increase in the capacitance density suggesting that it impedes oxygen reaction with silicon to produce SiO2. It is later observed that a W metal capping layer can serve as a high-oxygen source, which results in an increased interfacial SiO2 formation. By limiting the oxygen content in the W capping layer and by utilizing a thermally stable TaN gate electrode, control over the electrical properties of the MOS device is acquired. To determine the stability of amorphous lanthanum-silicate in contact with investigated by means of back-side secondary ion mass spectroscopy profiling. The results are the first reported data showing that the lanthanum incorporated in the silica matrix doe not diffuse into the silicon substrate after high temperature processing. The decrease in the device effective work function (?M,eff ) observed in these samples is examined in detail. First, as a La 2O3 capping layer on HfSiO(N), the shift yields ideal-? M,eff values for nMOSFET deices (4.0 eV) that were previously inaccessible. Other lanthanide oxides (Dy, Ho and Yb) used as capping layers show similar effects. It is also shown that tuning of ?M,eff can be realized by controlling the extent of lanthanide-silicate formation. This research, conducted in conjunction with SEMATECH and the SRC, represents a significant technological advancement in realizing 45 and sub-45 nm MOSFET device nodes.

Jur, Jesse Stephen

428

Coupling of the 4f Electrons in Lanthanide Molecules  

SciTech Connect

(C5Me5)2LnOTf where Ln = La, Ce, Sm, Gd, and Yb have been synthesized and these derivatives are good starting materials for the synthesis of (C5Me5)2LnX derivatives. (C5Me5)2Ln(2,2'-bipyridine), where Ln = La, Ce, Sm, and Gd, along with several methylated bipyridine analogues have been synthesized and their magnetic moments have been measured as a function of temperature. In lanthanum, cerium, and gadolinium complexes the bipyridine ligand ligand is unequivocally the radical anion, and the observed magnetic moment is the result of intramolecular coupling of the unpaired electron on the lanthanide fragment with the unpaired electron on the bipyridine along with the intermolecular coupling between radicals. Comparison with the magnetic moments of the known compounds (C5Me5)2Sm(2,2'-bipyridine) and (C5Me5)2Yb(2,2'-bipyridine) leads to an understanding of the role of the Sm(II)/Sm(III) and Yb(II)/Yb(III) couple in the magnetic properties of (C5Me5)2Sm(2,2'-bipyridine) and (C5Me5)2Yb(2,2'-bipyridine). In addition, crystal structures of (C5Me5)2Ln(2,2'-bipyridine) and [(C5Me5)2Ln(2,2'-bipyridine)][BPh4](Ln= Ce and Gd), where the lanthanide is unequivocally in the +3 oxidation state, give the crystallographic characteristics of bipyridine as an anion and as a neutral ligand in the same coordination environment, respectively. Substituted bipyridine ligands coordinated to (C5Me5)2Yb are studied to further understand how the magnetic coupling in (C5Me5)2Yb(2,2'-bipyridine) changes with substitutions. In the cases of (C5Me5)2Yb(5,5'-dimethyl-2,2'-bipyridine) and (C5Me5)2Yb(6-methyl-2,2'-bipyridine), the valence, as measured by XANES, changes as a function of temperature. In general, the magnetism in complexes of the type (C5Me5)2Yb(bipy.-), where bipyo represents 2,2'-bipyridine and substituted 2,2'-bipyridine ligands, is described by a multiconfiguration model, in which the ground state is an open-shell singlet composed of two configurations: Yb(III, f13)(bipy.-) and Yb(II, f14)(bipyo). The relative contributions of the two configurations depends on the substituents on the bipyridine ligand.[(C5H4Me)3Ln]2(L) (Ln = Ce, Tb; L = 4,4'-bipyridine, 1,4-benzoquinone) are synthesized in order to study the effect of these ligands on the oxidation states of the metal as well as to study intramolecular coupling between two lanthanides fragments.

Kazhdan, Daniel

2008-09-12

429

Advanced Extraction Methods for Actinide/Lanthanide Separations  

SciTech Connect

The separation of An(III) ions from chemically similar Ln(III) ions is perhaps one of the most difficult problems encountered during the processing of nuclear waste. In the 3+ oxidation states, the metal ions have an identical charge and roughly the same ionic radius. They differ strictly in the relative energies of their f- and d-orbitals, and to separate these metal ions, ligands will need to be developed that take advantage of this small but important distinction. The extraction of uranium and plutonium from nitric acid solution can be performed quantitatively by the extraction with the TBP (tributyl phosphate). Commercially, this process has found wide use in the PUREX (plutonium uranium extraction) reprocessing method. The TRUEX (transuranium extraction) process is further used to coextract the trivalent lanthanides and actinides ions from HLLW generated during PUREX extraction. This method uses CMPO [(N, N-diisobutylcarbamoylmethyl) octylphenylphosphineoxide] intermixed with TBP as a synergistic agent. However, the final separation of trivalent actinides from trivalent lanthanides still remains a challenging task. In TRUEX nitric acid solution, the Am(III) ion is coordinated by three CMPO molecules and three nitrate anions. Taking inspiration from this data and previous work with calix[4]arene systems, researchers on this project have developed a C3-symmetric tris-CMPO ligand system using a triphenoxymethane platform as a base. The triphenoxymethane ligand systems have many advantages for the preparation of complex ligand systems. The compounds are very easy to prepare. The steric and solubility properties can be tuned through an extreme range by the inclusion of different alkoxy and alkyl groups such as methyoxy, ethoxy, t-butoxy, methyl, octyl, t-pentyl, or even t-pentyl at the ortho- and para-positions of the aryl rings. The triphenoxymethane ligand system shows promise as an improved extractant for both tetravalent and trivalent actinide recoveries form high level liquid wastes and a general actinide clean-up procedure. The selectivity of the standard extractant for tetravalent actinides, (N,N-diisobutylcarbamoylmethyl) octylphenylphosphineoxide (CMPO), was markedly improved by the attachment of three CMPO-like functions onto a triphenoxymethane platform, and a ligand that is both highly selective and effective for An(IV) ions was isolated. A 10 fold excess of ligand will remove virtually all of the 4+ actinides from the acidic layer without extracting appreciable quantities of An(III) and Ln(III) unlike simple CMPO ligands. Inspired by the success of the DIAMEX industrial process for extractions, three new tripodal chelates bearing three diglycolamide and thiodiglycolamide units precisely arranged on a triphenoxymethane platform have been synthesized for an highly efficient extraction of trivalent f-element cations from nitric acid media. A single equivalent of ligand will remove 80% of the Ln(III) ion from the acidic layer since the ligand is perfectly suited to accommodate the tricapped trigonal prismatic geometry preferred by the metal center. The ligand is perhaps the most efficient binder available for the heavier lanthanides and due to this unique attribute, the extraction event can be easily followed by 1H NMR spectroscopy confirming the formation of a TPP complex. The most lipophilic di-n-butyl tris-diglycolamide was found to be a significantly weaker extractant in comparison to the di-isopropyl analogs. The tris-thiodiglycolamide derivative proved to be an ineffective chelate for f-elements and demonstrated the importance of the etheric oxygens in the metal binding. The results presented herein clearly demonstrate a cooperative action of these three ligating groups within a single molecule, confirmed by composition and structure of the extracted complexes, and since actinides prefer to have high coordination numbers, the ligands should be particularly adept at binding with three arms. The use of such an extractant permits the extraction of metal ions form highly acidic environment through the ability

Scott, M.J.

2005-12-01

430

Shift Work: Improving Daytime Sleep  

MedlinePLUS

... be reprinted for personal, noncommercial use only. Shift work: Improving daytime sleep By Mayo Clinic staff Original ... multitasking and learn how to focus Healthy at work (4) Shift work: Improving daytime sleep Sitting risks: ...

431

Determination of lanthanides in rock samples by inductively coupled plasma mass spectrometry using thorium as oxide and hydroxide correction standard  

NASA Astrophysics Data System (ADS)

Determination of lanthanides by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) using modified mathematical correction method has been studied. Normally, the ICP-MS analysis of middle and heavier lanthanides becomes difficult by severe spectroscopic overlap of M +, MO + or MOH + ions from lighter lanthanides and Ba. A correction method based on a single element oxide yield measurement, is a simple approach to correct for the above spectroscopic overlaps. But the uncertainty in the oxide and hydroxide yields measurement of lanthanides and barium over a long period of time can lead to inaccurate results even under fixed plasma conditions. To correct this, thorium was adopted as an oxide and hydroxide correction standard. Using a ratio of lanthanide oxide yield to thorium oxide yield, the lanthanide correction factors (LCF) were established and incorporated in the mathematical correction scheme. The same factors were also established for hydroxide correction. The proposed modified correction scheme was applied to the determination of lanthanides by ICP-MS from the USGS Standard Rock samples AGV-1 and G-2. The results are in good agreement with the reported values. The method also proved to be useful in isotopic ratio measurement of lanthanides having severe isobaric overlaps.

Raut, Narendra M.; Huang, Li-Shing; Aggarwal, Suresh K.; Lin, King-Chuen

2003-05-01

432

GLASS FABRICATION AND PRODUCT CONSISTENCY TESTING OF LANTHANIDE BOROSHILICATE FRIT X COMPOSITION FOR PLUTONIUM DISPOSITION  

SciTech Connect

The Department of Energy Office of Environmental Management (DOE/EM) plans to conduct the Plutonium Disposition Project at the Savannah River Site (SRS) to disposition excess weapons-usable plutonium. A plutonium glass waste form is the preferred option for immobilization of the plutonium for subsequent disposition in a geologic repository. A reference glass composition (Lanthanide Borosilicate (LaBS) Frit B) was developed during the Plutonium Immobilization Program (PIP) to immobilize plutonium in the late 1990's. A limited amount of performance testing was performed on this baseline composition before efforts to further pursue Pu disposition via a glass waste form ceased. Recent FY05 studies have further investigated the LaBS Frit B formulation as well as development of a newer LaBS formulation denoted as LaBS Frit X. The objectives of this present task were to fabricate plutonium loaded LaBS Frit X glass and perform corrosion testing to provide near-term data that will increase confidence that LaBS glass product is suitable for disposal in the Yucca Mountain Repository. Specifically, testing was conducted in an effort to provide data to Yucca Mountain Project (YMP) personnel for use in performance assessment calculations. Plutonium containing LaBS glass with the Frit X composition with a 9.5 wt% PuO{sub 2} loading was prepared for testing. Glass was prepared to support Product Consistency Testing (PCT) at Savannah River National Laboratory (SRNL). The glass was thoroughly characterized using x-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) prior to performance testing. A series of PCTs were conducted at SRNL using quenched Pu Frit X glass with varying exposed surface areas. Effects of isothermal and can-in-canister heat treatments on the Pu Frit X glass were also investigated. Another series of PCTs were performed on these different heat-treated Pu Frit X glasses. Leachates from all these PCTs were analyzed to determine the dissolved concentrations of key elements. Acid stripping of leach vessels was performed to determine the concentration of the glass constituents that may have sorbed on the vessels during leach testing. Additionally, the leachate solutions were ultrafiltered to quantify colloid formation. Characterization of the quenched Pu Frit X glass prior to testing revealed that some crystalline plutonium oxide was present in the glass. The crystalline particles had a disklike morphology and likely formed via coarsening of particles in areas compositionally enriched in plutonium. Similar results had also been observed in previous Pu Frit B studies. Isothermal 1250 C heat-treated Pu Frit X glasses showed two different crystalline phases (PuO{sub 2} and Nd{sub 2}Hf{sub 2}O{sub 7}), as well as a peak shift in the XRD spectra that is likely due to a solid solution phase PuO{sub 2}-HfO{sub 2} formation. Micrographs of this glass showed a clustering of some of the crystalline phases. Pu Frit X glass subjected to the can-in-canister heating profile also displayed the two PuO{sub 2} and Nd{sub 2}Hf{sub 2}O{sub 7} phases from XRD analysis. Additional micrographs indicate crystalline phases in this glass were of varying forms (a spherical PuO{sub 2} phase that appeared to range in size from submicron to {approx}5 micron, a dendritic-type phase that was comprised of mixed lanthanides and plutonium, and a minor phase that contained Pu and Hf), and clustering of the phases was also observed.

Marra, J

2006-11-21

433

BiPO4: a better host for doping lanthanide ions.  

PubMed

In the present manuscript it is demonstrated that BiPO(4) is a better alternative to lanthanide phosphate host for making lanthanide ion-based luminescent materials. Hexagonal and monoclinic forms of BiPO(4) phase were prepared based on the reaction of Bi(3+) and PO(4)(3-) ions in ethylene glycol medium at 100 and 185 °C, respectively. From the differential thermal analysis (DTA) studies it is confirmed that the difference in the nucleation mechanism rather than the phase transition is responsible for the monoclinic phase formation at low temperatures (125 °C). Monoclinic BiPO(4) is quite stable and forms random solid solutions with lanthanide phosphates having both monoclinic (monazite) and tetragonal (xenotime) structures, as confirmed by XRD, FTIR and (31)P solid state nuclear magnetic resonance studies. On excitation corresponding to the (1)S(0)?(3)P(1) transition of Bi(3+) in BiPO(4):Ln samples, energy transfer from host to lanthanide ions takes place. The studies are quite relevant as there is a growing interest all over the world in replacing lanthanide based host used for different applications with easily available, easily purifiable and cheap main group elements (like Sb, Bi etc.) based hosts. PMID:22286329

Naidu, Boddu Sanyasi; Vishwanadh, Bathula; Sudarsan, Vasanthakumaran; Vatsa, Rajesh Kumar

2012-01-30

434

Distribution, speciation, and bioavailability of lanthanides in the Rhine-Meuse estuary, The Netherlands.  

PubMed

Changing environmental conditions may influence the fate and bioavailability of lanthanides (part of the rare earth elements [Ln]) in estuaries. The aim of this study was to quantify the variation in estuarine lanthanide solid/water distribution, speciation, and bioaccumulation. The latter was studied in the amphipod Corophium volutator under field and laboratory conditions. Calculations with the chemical equilibrium model MINEQL+ indicate that dissolved lanthanides are complexed mainly to carbonates and dissolved organic matter. In the water phase, the relative abundance of the free ion, LnCO3, and humic complexes decreases from lanthanum to lutetium, whereas the relative abundance of Ln(CO3)2 increases. Cerium and europium anomalies were found in the water. Europium anomalies were also found in some biota. The biota sediment accumulation factors (BSAFs) decreased across the series from lanthanum to lutetium. Regression analysis revealed that alkalinity correlated negatively with lanthanide uptake. This suggests that increasing complexation reduced bioavailability under the prevailing conditions. The BSAFs did not depend on salinity or pH, which may simplify sediment-quality criteria for fresh versus saline waters. Field BSAFs were significantly lower than laboratory values for the same sediments, which is explained by adaptation of the organisms to lanthanides. PMID:11521817

Moermond, C T; Tijink, J; van Wezel, A P; Koelmans, A A

2001-09-01

435

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.

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

436

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

437

Frequency-domain measurement of luminescent lanthanide chelates.  

PubMed

The sinusoidal modulation of excitation intensity and phase-sensitive detection of emission is ideally suitable for the accurate determination of the lifetime and intensity of lanthanide luminescence. In this work we elaborate on the general mathematical and instrumental techniques of the frequency-domain (FD) measurements in the low-frequency domain below 100 kHz. A modular FD luminometer is constructed by using a UV-LED as the excitation source, proper light filters in the excitation and emission paths, a photomultiplier with a fast preamplifier, and a conventional dual-phase lock-in amplifier. Starting from the set of linear differential equations governing the excited-state processes of the lanthanide chelates, an equation linking the luminescence intensity to the general form of the excitation modulation was derived. Application to the sinusoidal modulation in the Euler's exponential form gives the expression for the in-phase and out-of-phase signals of a dual-phase lock-in amplifier. It is shown that by using a relatively large number of logarithmically equidistant modulation frequencies it is possible to use the Kramers-Kronig relation for checking the compatibility of the out-of-phase and in-phase signals. As an example, the emission from two different europium(III) chelates were measured by using 200 modulation frequencies between 10 Hz and 100 kHz. In addition to the conventional transition between (5)D(0) and (7)F(2) levels emitting at 615 nm, also the emission from the transition between (5)D(1) and (7)F(1) levels at ca. 540 nm was measured. The latter emission was also measured at different temperatures, yielding the energy difference between the (5)D(1) and (5)D(0) levels. The relatively large number of modulation frequencies allows also an accurate determination of lifetimes and corresponding amplitudes by using an appropriate nonlinear regression method. Comparison of the time-domain and frequency-domain methods shows that the weighting of data is different and both methods have application areas of their own. PMID:20617797

Hyppänen, Iko; Soukka, Tero; Kankare, Jouko

2010-08-01

438

Sentiment Classification and Polarity Shifting  

Microsoft Academic Search

Polarity shifting marked by various linguistic structures has been a challenge to automatic sentiment classification. In this paper, we propose a machine learning approach to incorporate polarity shifting information into a document-level sentiment classification system. First, a feature selection method is adopted to automatically generate the training data for a binary classifier on polarity shifting detection of sentences. Then, by

Shoushan Li; Sophia Yat Mei Lee; Ying Chen; Chu-Ren Huang; Guodong Zhou

2010-01-01

439

Mean shift-based clustering  

Microsoft Academic Search

In this paper, a mean shift-based clustering algorithm is proposed. The mean shift is a kernel-type weighted mean procedure. Herein, we first discuss three classes of Gaussian, Cauchy and generalized Epanechnikov kernels with their shadows. The robust properties of the mean shift based on these three kernels are then investigated. According to the mountain function concepts, we propose a graphical

Kuo-lung Wu; Miin-shen Yang

2007-01-01

440

THE MOB SHIFT SIMULATION FRAMEWORK  

Microsoft Academic Search

MOB SHIFT is a domain specific simulation framework enabling the timely and cost-effective analysis, design and evaluation of competing Mobile Offshore Base concepts. It was developed in SHIFT, a specification language for describing dynamic networks of hybrid automata. The expressive power of SHIFT provides a compact notation for modeling spatial and logical relationships in a dynamic environment and for modeling

J. Borges de Sous; A. Girard; N. Kourjanskaia

1999-01-01

441

Controlled release of dry reagents in porous media for tunable temporal and spatial distribution upon rehydration  

PubMed Central

Novel methods are demonstrated that enable controlled spatial and temporal rehydration of dried reagents in a porous matrix. These methods can be used in paper-based microfluidic assays to define reagent concentrations over time at zones downstream for improved performance, and can reduce costs by simplifying the manufacturing process with the use of a single porous substrate. First, the creation of uniform reagent pulses from patterned arrays of dried reagent is demonstrated. Second, reagents are stored dry in separate regions of the porous matrix so that they can be combined upon rehydration for immediate use in the device. Third, reagents are reconstituted sequentially from dry storage depots with tunable delivery times. Fourth, the total time for dissolution is varied to achieve a range of reagent delivery times to a downstream region. Finally, the utility of these control methods is demonstrated in the context of real-time reagent rehydration and mixing on a porous device.

Le, Huy Q.; Fu, Elain; Yager, Paul

2012-01-01

442

Blood Group Reagent Anti-c (H48) Human/Murine Monoclonal ...  

Center for Biologics Evaluation and Research (CBER)

... Resources for You. Blood Grouping and Phenotyping Reagents. -. Blood Group Reagent Anti-c (H48) Human/Murine Monoclonal (IgM). ... More results from www.fda.gov/biologicsbloodvaccines/bloodbloodproducts/approvedproducts

443

A Reagent for the Simultaneous Microscopic Determination of Quartz and Halides.  

National Technical Information Service (NTIS)

A reagent was discovered whereby the techniques of dispersion staining microscopy and spot testing may be combined to distinguish halite from quartz in samples of atmospheric dust. The preparation of the reagent and its application are discussed. (Author)

H. Nusbaum

1966-01-01

444

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

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3830 Treponema pallidum tre-ponemal test reagents. (a)...

2013-04-01

445

21 CFR 866.3410 - Proteus spp. (Weil-Felix) serological reagents.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3410 Proteus spp. (Weil-Felix) serological reagents. (a)...

2013-04-01

446

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

447

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.

2002-09-01

448

Microwave plasma synthesis of lanthanide zirconates from microwave transparent oxides.  

PubMed

Lanthanide zirconate phases Ln(2)Zr(2)O(7) and Ln(4)Zr(3)O(12) (Ln = Y, La, Gd, Dy, Ho, Yb) have been prepared using a microwave induced plasma methodology, which allows rapid synthesis using materials which do not couple directly with microwaves at room temperature. We describe the measurement of heating profiles of the precursor binary metal oxides which can be used to identify conditions conducive to the synthesis of more complex oxides. Uncontrolled heating which can be a feature of microwave synthesis of ceramics is not observed, allowing reproducible synthesis. Conventionally these phases are prepared at >1400 °C over hours or days and are being investigated for applications including the immobilisation of nuclear waste where rapid processing is important. Using the microwave plasma method, phase-pure materials have been prepared in minutes. Furthermore, it is clear that Ln(2)Zr(2)O(7) and Ln(4)Zr(3)O(12) also exhibit significant plasma-promoted dielectric heating (e.g. >2200 °C for Dy(4)Zr(3)O(12)) which is typically greater than either of the respective precursors, thus providing a driving force to rapidly complete the reaction. PMID:22215067

Chou, Yi-Hsin; Hondow, Nicole; Thomas, Chris I; Mitchell, Robert; Brydson, Rik; Douthwaite, Richard E

2012-01-04

449

Valence calculations of binding energies of mid-row lanthanides  

NASA Astrophysics Data System (ADS)

Binding energies of mid-row lanthanides have been calculated by taking advantage of the >90% LS purity of the 4f^n subgroups of their neutral ground states ootnotetextAtomic Energy Levels -- The Rare-Earth Elements, edited by W. C. Martin, R. Zalubas, and L. Hagan, Natl. Bur. Stand. Ref. Data Ser. Natl. Bur. Stand. (U.S.) Circ. No. 60 (U.S. GPO, Washington, D.C., 1978).. As described in our recent work on Nd^- ootnotetextS. M. O'Malley and D. R. Beck, Phy. Rev. A 77, 012505 (2008)., the 4f^n electrons were treated as core-like and restricted to a single LS term throughout all Dirac-Fock and correlation configurations, resulting in manageable relativistic configuration-interaction calculations for these computationally complex systems. Several weakly bound 6p attachments (<200 meV) were found for each negative ion, and these were carefully analyzed with respect to approximate LS total configuration as well as the j's of the the 4f^n subgroup and 6p electron.

O'Malley, Steven M.; Beck, Donald R.

2008-05-01

450

Spectrometer for lanthanides' K x-ray fluorescence  

SciTech Connect

X-ray fluorescence analysis is a highly useful technique for determining the chemical composition of matter. The present article describes the successful development of a wavelength-dispersive x-ray fluorescence spectrometer for a fairly high-energy range, 30-60 keV, that can contribute to studying lanthanides' K{beta} spectra with high-energy resolution. By combining a new high-energy synchrotron light source and the present spectrometer, it has been demonstrated that the full width at half maximum for lanthanum's K{beta}{sub 1} is 32 eV and that all the peaks in the spectra are fully resolved. This corresponds to an energy resolution E/{delta}E of 1180, which is ten times better than a conventional system based on a Ge detector, which can detect only two peaks, K{beta}{sub 1} and K{beta}{sub 2}, in seven peaks. The present spectrometer can open up a new field in x-ray spectrometry.

Sakurai, Kenji; Mizusawa, Mari; Terada, Yasuko [National Institute for Materials Science, Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Japan Synchrotron Radiation Research Institute, SPring-8, Sayo-gun, Hyogo 679-5198 (Japan)

2007-06-15

451

Series of lanthanide organometallic single-ion magnets.  

PubMed

The synthesis, structures, and magnetic properties of a series of lanthanide organometallic mixed sandwich molecules, (Cp*)Ln(COT), are investigated, where Cp* is the pentamethylcyclopentadiene anion and COT is the cyclooctatetraene dianion and Ln represents Tb(III), Dy(III), Ho(III), Er(III), and Tm(III). Among the five complexes, Dy and Ho complexes are determined to be single-ion magnets in addition to the previously reported Er complex. Both Dy and Ho complexes show obvious quantum tunneling magnetization relaxation in the absence of a static field. The diluted Ho complex behaves two sets of thermally activated relaxation as we reported previously in Er due to the COT ring static disorder. A stair-shaped hysteresis for the Er compound can be observed at 1.6 K with Hc = 1 kOe at a sweeping rate over 700 Oe/s. The quantum tunneling decoherence relaxation rate increases from Er to Ho to Dy, which may be caused by the relative increase of transverse anisotropy coming from the larger tilting of the two aromatic rings within the molecule. The fine electronic structure is analyzed with ligand-field theory employing the effective Hamiltonian method. The zero-field splitting is determined to be Ising type, and the energy gap between the ground state and the first excited one is consistent with the barrier obtained by Arrhenius analysis. PMID:22356450

Jiang, Shang-Da; Liu, Shan-Shan; Zhou, Li-Nan; Wang, Bing-Wu; Wang, Zhe-Ming; Gao, Song

2012-02-22

452

Highly Luminescent Lanthanide Complexes of 1 Hydroxy-2-pyridinones  

SciTech Connect

The synthesis, X-ray structure, stability, and photophysical properties of several trivalent lanthanide complexes formed from two differing bis-bidentate ligands incorporating either alkyl or alkyl ether linkages and featuring the 1-hydroxy-2-pyridinone (1,2-HOPO) chelate group in complex with Eu(III), Sm(III) and Gd(III) are reported. The Eu(III) complexes are among some of the best examples, pairing highly efficient emission ({Phi}{sub tot}{sup Eu} {approx} 21.5%) with high stability (pEu {approx} 18.6) in aqueous solution, and are excellent candidates for use in biological assays. A comparison of the observed behavior of the complexes with differing backbone linkages shows remarkable similarities, both in stability and photophysical properties. Low temperature photophysical measurements for a Gd(III) complex were also used to gain insight into the electronic structure, and were found to agree with corresponding TD-DFT calculations for a model complex. A comparison of the high resolution Eu(III) emission spectra in solution and from single crystals also revealed a more symmetric coordination geometry about the metal ion in solution due to dynamic rotation of the observed solid state structure.

University of California, Berkeley; Lawrence National Laboratory; Raymond, Kenneth; Moore, Evan G.; Xu, Jide; Jocher, Christoph J.; Castro-Rodriguez, Ingrid; Raymond, Kenneth N.

2007-11-01

453

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

454

Selective extraction of trivalent actinides from lanthanides with dithiophosphinic acids and tributylphosphate  

SciTech Connect

A variety of chemical systems have been developed to separate trivalent actinides from lanthanides based on the slightly stronger complexation of the trivalent actinides with ligands that contain soft donor atoms. The greater stability of the actinide complexes in these systems has often been attributed to a slightly greater covalent bonding component for the actinide ions relative to the lanthanide ions. The authors have investigated several synergistic extraction systems that use ligands with a combination of oxygen and sulfur donor atoms that achieve a good group separation of the trivalent actinides and lanthanides. For example, the combination of dicyclohexyldithiophosphinic acid and tributylphosphate has shown separation factors of up to 800 for americium over europium in a single extraction stage. Such systems could find application in advanced partitioning schemes for nuclear waste.

Jarvinen, G.; Barrans, R.; Schroeder, N.; Wade, K.; Jones, M.; Smith, B.F. [Los Alamos National Lab., NM (United States); Mills, J.; Howard, G. [Texas Tech Univ., Lubbock, TX (United States); Freiser, H.; Muralidharan, S. [Arizona Univ., Tucson, AZ (United States)

1995-01-01

455

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

456

Combinatorial discovery of lanthanide-doped nanocrystals with spectrally pure upconverted emission.  

PubMed

Nanoparticles doped with lanthanide ions exhibit stable and visible luminescence under near-infrared excitation via a process known as upconversion, enabling long-duration, low-background biological imaging. However, the complex, overlapping emission spectra of lanthanide ions can hinder the quantitative imaging of samples labeled with multiple upconverting probes. Here, we use combinatorial screening of multiply doped NaYF(4) nanocrystals to identify a series of doubly and triply doped upconverting nanoparticles that exhibit narrow, spectrally pure emission spectra at various visible wavelengths. We then developed a comprehensive kinetic model validated by our extensive experimental data set. Applying this model, we elucidated the energy transfer mechanisms giving rise to spectrally pure emission. These mechanisms suggest design rules for electronic level structures that yield robust color tuning in lanthanide-doped upconverting nanoparticles. The resulting materials will be useful for background-free multicolor imaging and tracking of biological processes. PMID:22713101

Chan, Emory M; Han, Gang; Goldberg, Joshua D; Gargas, Daniel J; Ostrowski, Alexis D; Schuck, P James; Cohen, Bruce E; Milliron, Delia J

2012-06-19

457

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

458

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

459

New violet-excitable reagents for multicolor flow applications.  

PubMed

We have recently added three new fluorophores-BD Horizon™ V450, BD Horizon V500, and BD Horizon V550 (V450, V500, and V550; BD Biosciences, San Jose, CA) to our existing AmCyan product, forming a group of four violet-excitable dyes from which we have produced functional antibody conjugates. These conjugates, with emission maxima that range from 450 to 535 nm, are compatible with multilaser flow cytometry (FCM) and can be used for polychromatic FCM in three-color or two-color combinations; in fact, V500 fills a spectral opening that has thus far not been exploited by other manufacturers of FCM reagents. We here report that conjugates based on BD Horizon dyes performed well within a useful sensitivity range, established by testing a representative group of violet-excitable FCM reagents currently available, and that V500 has better compatibility with FITC in multicolor applications than does AmCyan. PMID:23765858

Abrams, Barny; Diwu, Zhenjun; Guryev, Oleg; Suni, Maria; Dubrovsky, Tim

2013-06-13

460

Experimental research of photodynamic diagnosis mediated by chemiluminescence reagents  

NASA Astrophysics Data System (ADS)

There are some serious limitations existing in conventional photodynamic diagnosis (PDD), such as autofluorescence disturbance, weak red-band absorption efficacy of traditional photosensitizers and quite short penetration depth of excitation light. In this paper a novel method of PDD mediated by chemiluminescence reagents is presented in fabricated mixed samples. Photodynamic therapy (PDT) is believed to act via singlet oxygen (1O2) generated by energy from photosensitizers. 5-Fluoresceinyl Cypridina Luciferin Analog (FCLA), a chemiluminescence reagent, can react with singlet oxygen and emit chemiluminescence with peak wavelength about at 526 nm. In the experiments, FCLA was chosen as an optical reporter of localization of singlet oxygen produced from photosensitized reaction of Hematoporphyrin Derivative (HpD) excited by 630 nm laser. Experimental results, the measurement of fluorescence spectra and the detection of image from chemiluminescence, show that the mixed HpD and FCLA in biologic tissue mixture excited with the laser of 630 nm can emit detectable light signals.

Wang, Juan; Xing, Da; Tang, Yonghong; He, Yonghong

2000-10-01

461

Preparation and purification of zinc sulfinate reagents for drug discovery.  

PubMed

The present protocol details the synthesis of zinc bis(alkanesulfinate)s that can be used as general reagents for the formation of radical species. The zinc sulfinates described herein are generated from the corresponding sulfonyl 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. Although the synthesis of the zinc sulfinate salts can generally be completed 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 sulfinate reagents over the course of 1 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

2013-05-02

462

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

2013-02-11

463

Enantioselective outer-sphere complexation of lanthanide(III) tris (pyridine-2,6-dicarboxylate) chelates with vitamin B 12 derivatives. An NMR and CD study  

NASA Astrophysics Data System (ADS)

The binding of three corrinoids, cyanocobalarnin (vitamin B 12, CNCbl), aquacobalamin (vitamin B 12a, H 2OCbl +) and dicyanocobinamide ((CN) 2Cbi), collectively denoted by Q, to the ?- and ?-enantiomer of Ln(DPA) 33- complexes (Ln=lanthanide, DPA=2,6-pyridine dicarboxylate) in aqueous solution at room temperature is investigated by NMR and Circular Dichroism (CD) spectroscopy. Tb(DPA) 33- induces shifts of the 1H-NMR resonances of Q. A formula, describing the dipolar interaction between the proton spin and the paramagnetic moment of the lanthanide complex, is fitted to the lanthanide induced shifts, yielding the position of Tb(DPA) 33- and the orientation of its magnetic axis with respect to the corrinoid. The magnitude of the shifts provide the value of Kavg, an average of the association constants of the two diastereomeric complexes {?-Tb(DPA) 33-Q) and {?-Tb(DPA) 33-Q}. We find Kavg=4±0.5 (B 12) and 0.8±0.2 M -1 ((CN) 2Cbi). The value for H 2OCbl + depends strongly on the solution's ionic strength I: Kavg=(7±1)×10 1, 22±5 and 16±7 M -1 at I=0.007, 0.12 and 0.22 M, respectively. The addition of the corrinoids to a (racemic) solution of Nd(DPA) 33-, induces CD in the electronic Nd(III) transitions in the 700-800 nm region (ICD). This Pfeiffer effect is attributed to an excess of ?-Nd(DPA) 33- in the enantioselective, outer-sphere association with the corrinoids. From the magnitude of the ICD as a function of [Q], in conjunction with the (indirectly) determined CD effect of ?-Nd(DPA) 33-, values are determined for K?- K?. We find K?- K?=-24±2 M -1 for H 2OCbl + at pH 6.7 and I=0.12 M and -12±2 M -1 at I=0.22 M; -4.4±0.5 M -1 for CNCbl and -0.9±0.3 M -1 for (CN) 2Cbi. Adopting the view that in the lanthanide series Ln(DPA) 33- chelates are isostructural, the results of the NMR and CD experiments are combined to estimate the enantioselectivity in the binding Eb, defined as ( K?- K?)/2 Kavg. We find Eb=-0.5±0.2 for H 2OCbl +, -0.7±0.2 for CNCbl and -0.7±0.3 for (CN) 2Cbi. On the basis of the NMR data, a molecular structure is proposed for the two diastereomeric {Ln(DPA) 33-Q} complexes. The bonding involves hydrogen bonds between the amide proton on the a and g side chain of the corrinoid and the carboxylate oxygen of two DPA ligands.

Meskers, Stefan C. J.; Dekkers, Harry P. J. M.

1999-08-01

464

Development of an in vitro model for assessing the in vivo stability of lanthanide chelates.  

PubMed

An in vitro model was developed to evaluate the in vivo stability of lanthanide polyaminocarboxylate complexes. The ligand-to-metal ratios for the chelates EDTA, CDTA, DTPA, MA-DTPA (monoamide-DTPA) and DOTA with the lanthanides lanthanum, samarium, and lutetium were optimized to achieve > or = 98% complexation yield for the resultant radiolanthanide complexes. The exchange of the radiolanthanides from their EDTA, CDTA, DTPA, MA-DTPA and DOTA complexes with Ca(2+) was determined by in vitro adsorption and in vitro column studies using hydroxyapatite (HA), an in vitro bone model. In vitro serum stability of these radiolanthanide complexes was used as an additional indicator of in vivo stability, although the mechanism of instability in serum will be different than with bone. The in vitro studies were consistent with the expected findings that the smallest lanthanide (Lu) formed the most stable complexes. In vivo studies were done to validate the in vitro model. Biodistribution studies in normal CF-1 mice showed that in vivo stability of the complex (i.e., the more lanthanide remaining in complex form) could be assessed by a combination of the urinary, bone and liver uptake. For example, biodistribution studies demonstrate that high urinary excretion correlated with complex stability, while high liver plus bone uptake correlated with complex instability. The urinary excretion of the EDTA complexes decreased from (177)Lu to (140)La indicating a loss in stability in the direction of (140)La, consistent with the in vitro studies. The more stable a lanthanide complex is, the lower its exchange with HA in vitro will be, and the lower its combined bone plus liver uptake and higher its urinary excretion will be in vivo. This investigation indicates that the in vivo stability can be determined by a screening method that measures the degree of exchange from the lanthanide chelate with hydroxyapatite (HA) and its serum stability. PMID:11295425

Li, W P; Ma, D S; Higginbotham, C; Hoffman, T; Ketring, A R; Cutler, C S; Jurisson, S S

2001-02-01

465

Novel lanthanide-based polymeric chains and corresponding ultrafast dynamics in solution.  

PubMed

Two types of structurally related one-dimensional coordination polymers were prepared by reacting lanthanide trichloride hydrates [LnCl(3)·(H(2)O)(m)] with dibenzoylmethane (Ph(2)acacH) and a base. Using cesium carbonate (Cs(2)CO(3)) and praseodymium, neodymium, samarium, or dysprosium salts yielded [Cs{Ln(Ph(2)acac)(4)}](n) (Ln = Pr (1), Nd (2), Sm (3), Dy (4)) in considerable yields. Reaction of potassium tert-butoxide (KOtBu) and the neodymium salt [NdCl(3)·(H(2)O)(6)] with Ph(2)acacH resulted in [K{Nd(Ph(2)acac)(4)}](n) (5). All polymers exhibit a heterobimetallic backbone composed of alternating lanthanide and alkali metal atoms which are bridged by the Ph(2)acac ligands in a linear fashion. ESI-MS investigations on DMF solutions of 1-5 revealed a dissociation of all the five compounds upon dissolution, irrespective of the individual lanthanide and alkali metal present. Temporal profiles of changes in optical density were acquired performing pump/probe experiments with DMF solutions of 1-5 via femtosecond laser spectroscopy, highlighting a lanthanide-specific relaxation dynamic. The corresponding relaxation times ranging from seven picoseconds to a few hundred picoseconds are strongly dependent on the central lanthanide atom, indicating an intramolecular energy transfer from ligands to lanthanides. This interpretation also demands efficient intersystem crossing within one to two picoseconds from the S(1) to T(1) level of the ligands. Magnetic studies show that [Cs{Dy(Ph(2)acac)(4)}](n) (4) has slow relaxation of the magnetization arising from the single Dy(3+) ions and can be described as a single-ion single molecule magnet (SMM). Below 0.5 K, hysteresis loops of the magnetization are observed, which show weak single chain magnet (SCM) behavior. PMID:22066577

Thielemann, Dominique T; Klinger, Melanie; Wolf, Thomas J A; Lan, Yanhua; Wernsdorfer, Wolfgang; Busse, Madleen; Roesky, Peter W; Unterreiner, Andreas-N; Powell, Annie K; Junk, Peter C; Deacon, Glen B

2011-11-08

466

Thermodynamic and Spectroscopic Studies of Lanthanides(III) Complexation with Polyamines in Dimethyl Sulfoxide  

SciTech Connect

The thermodynamic parameters of complexation of Ln(III) cations with tris(2-aminoethyl)amine (tren) and tetraethylenepentamine (tetren) were determined in dimethyl sulfoxide (DMSO) by potentiometry and calorimetry. The excitation and emission spectra and luminescence decay constants of Eu3+ and Tb3+ complexed by tren and tetren, as well as those of the same lanthanides(III) complexed with diethylenetriamine (dien) and triethylenetetramine (trien), were also obtained in the same solvent. The combination of thermodynamic and spectroscopic data showed that, in the 1:1 complexes, all nitrogens of the ligands bound to the lanthanides except in the case of tren, in which only pendant N bound. For the larger ligands (trien, tren, tetren) in the higher complexes (ML2), there was less complete binding by available donors, presumably due to steric crowding. FT-IR studies were carried out in an acetonitrile/DMSO mixture, suitably chosen in order to follow the changes in the primary solvation sphere of lanthanide(III) due to complexation of amine ligands. Results show that the mean number of molecules of DMSO removed from the inner coordination sphere of lanthanides(III) is lower than ligand denticity and that the coordination number of the metal ions increases with amine complexation from ?8 to ?10. Independently of the number and structure of the amines, linear trends, similar for all lanthanides, were obtained by plotting the values of *Gj°, *Hj° and T*Sj° for the complexation of ethylenediamine (en), dien, trien, tren and tetren as a function of the number of amine metal-coordinated nitrogen atoms. The main factors on which the thermodynamic functions of lanthanide(III) complexation reactions in DMSO depend are discussed.

Di Bernardo, Plinio; Zanonato, Pier Luigi; Melchior, Andrea; Portanova, Roberto; Tolazzi, Marilena; Choppin, Gregory R.; Wang, Zheming

2008-02-04

467

21 CFR 864.9650 - Quality control kit for blood banking reagents.  

Code of Federal Regulations, 2010 CFR

...9650 Quality control kit for blood banking reagents. (a) Identification... A quality control kit for blood banking reagents is a device that consists of sera, cells, buffers, and antibodies used to determine...cells and reagents used for blood banking. (b)...

2010-04-01

468

21 CFR 864.9650 - Quality control kit for blood banking reagents.  

Code of Federal Regulations, 2010 CFR

...9650 Quality control kit for blood banking reagents. (a) Identification... A quality control kit for blood banking reagents is a device that consists of sera, cells, buffers, and antibodies used to determine...cells and reagents used for blood banking. (b)...

2009-04-01

469

21 CFR 864.9650 - Quality control kit for blood banking reagents.  

Code of Federal Regulations, 2013 CFR

...9650 Quality control kit for blood banking reagents. (a) Identification... A quality control kit for blood banking reagents is a device that consists of sera, cells, buffers, and antibodies used to determine...cells and reagents used for blood banking. (b)...

2013-04-01

470

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

471

Reversible protein affinity-labelling using bromomaleimide-based reagents.  

PubMed

Reversible protein biotinylation is readily affected via conjugation with a bromomaleimide-based reagent followed by reductive cleavage. The intermediate biotinylated protein constructs are stable at physiological temperature and pH 8.0. Quantitative reversibility is elegantly delivered under mild conditions of using a stoichiometric amount of a bis-thiol, thus providing an approach that will be of general interest in chemical biology and proteomics. PMID:23462873

Nathani, Ramiz I; Chudasama, Vijay; Ryan, Chris P; Moody, Paul R; Morgan, Rachel E; Fitzmaurice, Richard J; Smith, Mark E B; Baker, James R; Caddick, Stephen

2013-03-05

472

Selectivity of reagents used to extract iron from soil  

Microsoft Academic Search

The selectivity of the Tamm and Mehra-Jackson reagents to iron (hydr)oxides was verified chemically by comparing the efficiencies\\u000a of the two methods of iron extraction: parallel (commonly adopted) and sequential, i.e., by calculating the difference ?Fe\\u000a = [Fedit ? (Feox(paral) + Fedit(seq))]. The expected equality of the extracted iron (i.e., ?Fe ? 0) is rarely observed. A positive balance reaching

Yu. N. Vodyanitskii; A. A. Vasil’ev; E. G. Morgun; K. A. Rumyantseva

2007-01-01

473

Use of fenton reagent to improve organic chemical biodegradability  

Microsoft Academic Search

Fenton reagent has been used to test the degradation of different organic compounds (formic acid, phenol, 4-chlorophenol, 2,4-dichlorophenol and nitrobenzene) in aqueous solution. A stoichiometric coefficient for the Fenton reaction was found to be 0.5mol of organic compound\\/mol of hydrogen peroxide, except for the formic acid where a value of approximately one was obtained (due to the direct formation of

E. Chamarro; A. Marco; S. Esplugas

2001-01-01

474

Tributyltin Solubilization and Degradation from Spiked Kaolin Using Different Reagents  

Microsoft Academic Search

Conditions for tributyltin (TBT) solubilization and degradation were investigated. These conditions were optimized to remove\\u000a or degrade organotin compounds (OTC) in spiked kaolin. TBT-spiked kaolin and reagents with specific chemical properties were\\u000a tested in a batch reactor using a solid matrix model. The final concentrations of butyltin compounds in kaolin were determined\\u000a by gas chromatography coupled with a pulsed flame

Yan Yvon; Isabelle Le Hécho; Olivier F. X. Donard

2011-01-01

475

A new reagent method for descaling heat-exchanging equipment  

Microsoft Academic Search

Corrosion and electrochemical studies of metallic materials (steel, St2, 08Kh22N6T, 12KhI8NIOT, copper M3, brass L062~I, aluminum ADI, titanium VT-O) applicable fo~ fabrication of heat-exchanging equipment were made to explore the scope of industrial use of the new reagent method. The tests were carried out on a special setup (Fig. i). The extent of carbonate scale removal and the corrosion rate

L. A. Luchinina; T. D. Konovalova; F. K. Davlet'yarova

1986-01-01

476

Aminodifluorosulfinium tetrafluoroborate salts as stable and crystalline deoxofluorinating reagents.  

PubMed

Aminodifluorosulfinium tetrafluoroborate salts were found to act as efficient deoxofluorinating reagents when promoted by an exogenous fluoride source and, in most cases, exhibited greater selectivity by providing less elimination byproduct as compared to DAST and Deoxo-Fluor. Aminodifluorosulfinium tetrafluoroborates are easy handled crystalline salts that show enhanced thermal stability over dialkylaminosulfur trifluorides, are storage-stable, and unlike DAST and Deoxo-Fluor do not react violently with water. PMID:19799406

Beaulieu, Francis; Beauregard, Louis-Philippe; Courchesne, Gabriel; Couturier, Michel; LaFlamme, François; L'Heureux, Alexandre

2009-11-01

477

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

478

Identification of mimotopes of Mycobacterium leprae as potential diagnostic reagents  

PubMed Central

Background An early diagnostic test for detecting infection in leprosy is fundamental for reducing patients’ sequelae. The currently used lepromin is not adequate for disease diagnosis and, so far, no antigen to be used in intradermoreaction has proved to be sensitive and specific for that purpose. Aiming at identifying new reagents to be used in skin tests, candidate antigens were investigated. Methods Random peptide phage display libraries were screened by using antibodies from leprosy patients in order to identify peptides as diagnostic reagents. Results Seven different phage clones were identified using purified antibodies pooled from sera of leprosy patients. When the clones were tested with serum samples by ELISA, three of them, 5A, 6A and 1B, allowed detecting a larger number of leprosy patients when compared to controls. The corresponding peptides expressed by selected phage clones were chemically synthesized. A pilot study was undertaken to assess the use of peptides in skin tests. The intradermal challenge with peptides in animals previously sensitized with Mycobacterium leprae induced a delayed-type hypersensitivity with peptide 5A (2/5) and peptide 1B (1/5). In positive controls, there was a 3/5 reactivity for lepromin and a 4/5 reactivity of the sensitized animals with soluble extract of M. leprae. Conclusions The preliminary data suggest that may be possible to develop reagents with diagnostic potential based on peptide mimotopes selected by phage display using polyclonal human antibodies.

2013-01-01

479

Ground-state configurations and unresolved transition arrays in extreme ultraviolet spectra of lanthanide ions  

SciTech Connect

Theoretical ground-state configurations of lanthanide ions calculated with the Cowan suite of codes are presented. Theoretical 4d-4f and 4p-4d spectra of Pd-like to Rb-like lanthanide ions calculated using the relativistic flexible atomic code are also shown. The effects of configuration interaction are investigated, and the results compare favorably with experiments in which, for increasing nuclear charge, strong emission peaks are observed to move toward shorter wavelength. The application of these strong emitters as extreme ultraviolet radiation sources, a topic of emerging interest, is discussed.

Kilbane, D.; O'Sullivan, G. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)

2010-12-15

480

Lanthanide impurities in wide bandgap semiconductors: A possible roadmap for spintronic devices  

NASA Astrophysics Data System (ADS)

The electronic properties of lanthanide (from Eu to Tm) impurities in wurtzite gallium nitride and zinc oxide were investigated by first principles calculations, using an all electron methodology plus a Hubbard potential correction. The results indicated that the 4f-related energy levels remain outside the bandgap in both materials, in good agreement with a recent phenomenological model, based on experimental data. Additionally, zinc oxide doped with lanthanide impurities became an n-type material, showing a coupling between the 4f-related spin polarized states and the carriers. This coupling may generate spin polarized currents, which could lead to appl