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1

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

SciTech Connect

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

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

1994-08-01

2

Lanthanide complexes of aminophosphonates as shift reagents for 7Li and 23Na NMR studies in biological systems.  

PubMed

A systematic NMR characterization of various Dy(III) complexes of linear and macrocyclic aminophosphonates as 7Li and 23Na NMR shift reagents for biological systems was undertaken. Their efficacy as shift reagents (SR) was tested under constant aqueous solution ionic strength conditions at pH 7.5 as a function of rho = [SR]/[M+]. Further characterization of the two best SRs, Dy(PcPcP)2(7-) and Dy(DOTP)5-, led to the conclusion that, although quite sensitive to solution pH and the presence of alkali metal ions and Mg2+ and Ca2+, these complexes were stable towards hydrolysis by phosphatases. The lack of precipitation of its solutions in the presence of Ca2+, allowed the choice of Dy(DOTP)5- as the best overall SR for biological studies. Other SRs, like Dy(TTHA)3-, although less sensitive to pH and to divalent ions, require significantly higher concentrations to yield the same shifts, leading to large bulk susceptibility artifacts in perfused tissues and organs. PMID:1467337

Ramasamy, R; Castro, M M; de Freitas, D M; Geraldes, C F

1992-01-01

3

Supramolecular chemical shift reagents inducing conformational transitions: NMR analysis of carbohydrate homooligomer mixtures.  

PubMed

We introduce the concept of supramolecular chemical shift reagents as a tool to improve signal resolution for the NMR analysis of homooligomers. Non-covalent interactions with the shift reagent can constrain otherwise flexible analytes inducing a conformational transition that results in signal separation. Here we use this approach for the quantitative analysis of a complex homooligomeric glycan mixture. PMID:25604578

Beeren, Sophie R; Meier, Sebastian

2015-02-01

4

Highly Emitting Near-Infrared Lanthanide “Encapsulated Sandwich” Metallacrown Complexes with Excitation Shifted Toward Lower Energy  

PubMed Central

Near-infrared (NIR) luminescent lanthanide complexes hold great promise for practical applications, as their optical properties have several complementary advantages over organic fluorophores and semiconductor nanoparticles. The fundamental challenge for lanthanide luminescence is their sensitization through suitable chromophores. The use of the metallacrown (MC) motif is an innovative strategy to arrange several organic sensitizers at a well-controlled distance from a lanthanide cation. Herein we report a series of lanthanide “encapsulated sandwich” MC complexes of the form Ln3+[12-MCZn(II),quinHA-4]2[24-MCZn(II),quinHA-8] (Ln3+[Zn(II)MCquinHA]) in which the MC framework is formed by the self-assembly of Zn2+ ions and tetradentate chromophoric ligands based on quinaldichydroxamic acid (quinHA). A first-generation of luminescent MCs was presented previously but was limited due to excitation wavelengths in the UV. We report here that through the design of the chromophore of the MC assembly, we have significantly shifted the absorption wavelength toward lower energy (450 nm). In addition to this near-visible inter- and/or intraligand charge transfer absorption, Ln3+[Zn(II)MCquinHA] exhibits remarkably high quantum yields, long luminescence lifetimes (CD3OD; Yb3+, QLnL = 2.88(2)%, ?obs = 150.7(2) ?s; Nd3+, QLnL = 1.35(1)%, ?obs = 4.11(3) ?s; Er3+, QLnL = 3.60(6)·10–2%, ?obs = 11.40(3) ?s), and excellent photostability. Quantum yields of Nd3+ and Er3+ MCs in the solid state and in deuterated solvents, upon excitation at low energy, are the highest values among NIR-emitting lanthanide complexes containing C–H bonds. The versatility of the MC strategy allows modifications in the excitation wavelength and absorptivity through the appropriate design of the ligand sensitizer, providing a highly efficient platform with tunable properties. PMID:24432702

2015-01-01

5

Highly emitting near-infrared lanthanide "encapsulated sandwich" metallacrown complexes with excitation shifted toward lower energy.  

PubMed

Near-infrared (NIR) luminescent lanthanide complexes hold great promise for practical applications, as their optical properties have several complementary advantages over organic fluorophores and semiconductor nanoparticles. The fundamental challenge for lanthanide luminescence is their sensitization through suitable chromophores. The use of the metallacrown (MC) motif is an innovative strategy to arrange several organic sensitizers at a well-controlled distance from a lanthanide cation. Herein we report a series of lanthanide “encapsulated sandwich” MC complexes of the form Ln3+ [12-MC(Zn(II),quinHA)-4]2[24-MC(Zn(II),quinHA)-8] (Ln3+ [Zn(II)MC(quinHA)]) in which the MC framework is formed by the self-assembly of Zn2+ ions and tetradentate chromophoric ligands based on quinaldichydroxamic acid (quinHA). A first-generation of luminescent MCs was presented previously but was limited due to excitation wavelengths in the UV. We report here that through the design of the chromophore of the MC assembly, we have significantly shifted the absorption wavelength toward lower energy (450 nm). In addition to this near-visible inter- and/or intraligand charge transfer absorption, Ln3+ [Zn(II)MC(quinHA)] exhibits remarkably high quantum yields, long luminescence lifetimes (CD3OD; Yb3+, QLn(L) = 2.88(2)%, ?obs = 150.7(2) ?s; Nd3+, QLn(L) = 1.35(1)%, ?obs = 4.11(3) ?s; Er3+, QLn(L) = 3.60(6)·10–2%, ?obs = 11.40(3) ?s), and excellent photostability. Quantum yields of Nd3+ and Er3+ MCs in the solid state and in deuterated solvents, upon excitation at low energy, are the highest values among NIR-emitting lanthanide complexes containing C–H bonds. The versatility of the MC strategy allows modifications in the excitation wavelength and absorptivity through the appropriate design of the ligand sensitizer, providing a highly efficient platform with tunable properties. PMID:24432702

Trivedi, Evan R; Eliseeva, Svetlana V; Jankolovits, Joseph; Olmstead, Marilyn M; Petoud, Stéphane; Pecoraro, Vincent L

2014-01-29

6

Rapid screening for monensin residues in poultry plasma by a dry reagent dissociation enhanced lanthanide fluoroimmunoassay.  

PubMed

Monensin, a carboxylic acid ionophore, is commonly fed to poultry to control coccidiosis. A method for rapid analysis of unextracted poultry plasma samples has been developed based on a novel immunoassay format: one-step all-in-one dry reagent time resolved fluorimetry. All assay specific components were pre-dried onto microtitration plate wells. Only addition of the serum sample diluted in assay buffer was required to perform analysis. Results were available one hour after sample addition. The limit of detection (mean +/- 3s) of the assay calculated from the analysis of 23 known negative samples was 14.2 ng ml-1. Intra- and inter-assay RSD were determined as 15.2 and 7.4%, respectively, using a plasma sample fortified with 50 mg ml-1 monensin. Eight broiler chickens were fed monensin at a dose rate of 120 mg kg-1 feed for one week, blood sampled then slaughtered without drug withdrawal. Plasma monensin concentrations, as determined by the fluoroimmunoassay ranged from 101-297 ng ml-1. This compared with monensin liver concentrations, determined by LC-MS, which ranged from 13-41 ng g-1. The fluoroimmunoassay described is extremely user friendly, gives particularly rapid results and is suitable for the detection and quantification of plasma monensin residues. Data from medicated poultry suggest that analysis of plasma may be useful in predicting the extent of monensin liver residues. PMID:10435285

Crooks, S R; Fodey, T L; Gilmore, G R; Elliott, C T

1998-12-01

7

Imaging of intracellular sodium with shift reagent aided (23)Na CSI in isolated rat hearts.  

PubMed

23Na chemical shift imaging (CSI) in conjunction with shift reagents was used to obtain images of intracellular (Na(i)) and extracellular sodium (Na(e)) in isolated rat hearts. It was demonstrated that the increase of Na(i) concentration in ischemic myocardium can be detected with this technique. 3D acquisition-weighted (23)Na CSI datasets with a nominal spatial resolution of 1.7 x 1.7 x 2.9 mm were acquired in 30 min in normoxic hearts and in globally or locally ischemic hearts. The shift reagent Tm(DOTP)(5-) was used to discriminate Na(i) and Na(e) signals. Na(i) maps could be generated in ischemic hearts, but not in normoxic hearts as the signal-to-noise ratio is too low. The Na(i) signal increased by more than 100% and the Na(e) signal decreased by more than 50% in myocardium of globally ischemic hearts (n = 3) compared to normoxic hearts (n = 3). In hearts with an acute occlusion of the left anterior descending coronary artery (n = 3), there was a local Na(i) signal increase in the anterior wall in the range of 60-110% compared to remote, normoxic tissue. PMID:12111935

Weidensteiner, Claudia; Horn, Michael; Fekete, Elsbeth; Neubauer, Stefan; von Kienlin, Markus

2002-07-01

8

23Na NMR shift reagents enhance cardiac staircase effect in isolated perfused rat hearts.  

PubMed

The effects of the currently used (23)Na NMR shift reagents, dysprosium bis-triphosphate [Dy(PPP)(2)], dysprosium triethylenetriamine hexaacetate [Dy(TTHA)] and thulium 1,4,7, 10-tetraazacyclododecane-N,N',N",N"'-tetra(methylenephosphonate) [Tm(DOTP)] were studied in the rat heart cardiac staircase model. Rat hearts were perfused with low or normal extracellular free calcium ([Ca(o)](f)). At low [Ca(o)](f) (0.34 +/- 0.05 mM), hearts were perfused with Dy(PPP)(2) (group I), Dy(TTHA) (group II) or no shift reagent (group III), while at normal [Ca(o)](f) (1.25 +/- 0.15 mM), hearts were perfused with Tm(DOTP) (group IV), Dy(TTHA) (group V) or no shift reagent (group VI). Left ventricular developed pressure (LVDP) values in group I were significantly higher than in groups II and III (p < 0.01), while no significant differences were found between groups II and III. LVDP values in group IV were significantly higher than in groups V and VI (p < 0.05), while the LVDP values in groups V and VI were almost identical. Also, a positive correlation between pacing rate and intracellular sodium ([Na(i)]) was evident. The [Na(i)] values at high [Ca(o)](f) were significantly lower than at low [Ca(o)](f) at each pacing level (p <0.01), indicating a negative correlation between [Na(i)] and [Ca(o)](f). No statistical differences were found in [Na(i)] between groups I vs II and IV vs V, showing that determination of [Na(i)] is not affected by any of these shift reagents. Thus the different LVDP responses in groups I vs II and IV vs V were not mirrored in [Na(i)] changes. We hypothesize that a direct, sarcolemmal Ca-Dy(PPP)(2)-, or Ca-Tm(DOTP)-induced positive inotropic effect could be responsible for these Na(i)-independent LVDP increases in groups I and IV. PMID:10484815

Simor, T; Lóránd, T; Szöllösy, A; Gaszner, B; Digerness, S B; Elgavish, G A

1999-08-01

9

Measurement of intravascular Na(+) during increased CBF using (23)Na NMR with a shift reagent.  

PubMed

Sodium ions are intimately involved with neural activity. Thus, it is highly desirable to devise a way of mapping brain activity via sodium imaging. Sodium ions exist in the extravascular and intravascular spaces. To separate the two components, the shift reagent Tm(DOTP)(5-) was intravenously introduced into rats. Intravascular sodium changes in the rat brain were measured during increased blood flow induced by hypercapnia using volume-localized (23)Na-NMR. The intravascular sodium changes, equivalent to cerebral blood volume changes, are significant during hypercapnia conditions and correlate well with the increase in arterial pCO(2). This suggests that the intravascular sodium change is dominant in total (23)Na spectroscopy or imaging of the brain during blood flow increase induced by external perturbation. PMID:11746937

Ronen, I; Kim, S G

2001-01-01

10

The effects of the NMR shift-reagents Dy(PPP)2, Dy(TTHA) and Tm(DOTP) on developed pressure in isolated perfused rat hearts. The role of shift-reagent calcium complexes.  

PubMed

The 23Na NMR shift-reagent complexes (Dy(PPP)2, Dy(TTHA), and Tm(DOTP)) bind stoichiometric amounts of Ca2+. Thus, in perfused rat heart systems, a supplementation of Ca2+ is required to maintain the requisite extracellular free calcium concentration ([Ca(o)]f) and to approximate a physiological level of contractile function. The amount of reagent-bound Ca2+ in a heart perfusate that contains a shift-reagent depends on: (1) Ca2+ binding by excess ligand used during the preparation of the shift-reagent; and (2) the Ca2+ binding affinity of the shift-reagent. To address point 1), we introduced a 1H and 31P NMR spectroscopic titration method to quantify directly the concentration of the excess ligand. We also used this method to minimize the amount of excess ligand (L) and thus the amount of Ca*L complex. To address point (2), we determined the stepwise Kd (microm) values of the Ca complexes of the three shift-reagents.: Dy(PPP)2, Kd=0.09, Kd2=7.9; Dy(TTHA), Kd1=10.66, Kd2=10.12; and Tm(DOTP), K(d1)=0.502, Kd2=4.98. The Kd values of the Ca complexes of the phosphonate and triphosphate based shift-reagents, Tm(DOTP) and Dy(PPP)2, respectively, are lower than those of the polyaminocarboxylate-based Dy(TTHA), indicating stronger Ca binding affinities for the former two types of complexes. We have also shown a positive correlation between [Ca(o)]f and left ventricular developed pressure (LVDP) in perfused rat hearts. Dy(TTHA) has shown no effect on LVDP v[Ca(o)]f. The LVDP values in the presence of the phosphonate and triphosphate based shift-reagents, however, were significantly higher than expected from the [Ca(o)]f levels alone. Thus a positive inotropic effect, independent of [Ca(o)]f, is evident in the presence of Tm(DOTP) or Dy(PPP)2. PMID:11708840

Gaszner, B; Simor, T; Hild, G; Elgavish, G A

2001-11-01

11

Biological and Clinical Aspects of Lanthanide Coordination Compounds  

PubMed Central

The coordinating chemistry of lanthanides, relevant to the biological, biochemical and medical aspects, makes a significant contribution to understanding the basis of application of lanthanides, particularly in biological and medical systems. The importance of the applications of lanthanides, as an excellent diagnostic and prognostic probe in clinical diagnostics, and an anticancer material, is remarkably increasing. Lanthanide complexes based X-ray contrast imaging and lanthanide chelates based contrast enhancing agents for magnetic resonance imaging (MRI) are being excessively used in radiological analysis in our body systems. The most important property of the chelating agents, in lanthanide chelate complex, is its ability to alter the behaviour of lanthanide ion with which it binds in biological systems, and the chelation markedly modifies the biodistribution and excretion profile of the lanthanide ions. The chelating agents, especially aminopoly carboxylic acids, being hydrophilic, increase the proportion of their complex excreted from complexed lanthanide ion form biological systems. Lanthanide polyamino carboxylate-chelate complexes are used as contrast enhancing agents for Magnetic Resonance Imaging. Conjugation of antibodies and other tissue specific molecules to lanthanide chelates has led to a new type of specific MRI contrast agents and their conjugated MRI contrast agents with improved relaxivity, functioning in the body similar to drugs. Many specific features of contrast agent assisted MRI make it particularly effective for musculoskeletal and cerebrospinal imaging. Lanthanide-chelate contrast agents are effectively used in clinical diagnostic investigations involving cerebrospinal diseases and in evaluation of central nervous system. Chelated lanthanide complexes shift reagent aided 23Na NMR spectroscopic analysis is used in cellular, tissue and whole organ systems. PMID:18365075

Misra, Sudhindra N.; M., Indira Devi; Shukla, Ram S.

2004-01-01

12

The solution structure of Ln (DOTP) 5- complexxes. A comparison of lanthanide-induced paramagnetic shifts with the MMX energy-minimized structure  

NASA Astrophysics Data System (ADS)

Complexes between the trivalent lanthanide ions and the macrocyclic chelate 1,4,7,10-tetraazacyclododecane- N,N',N?,N?-tetra(methylene phosphonate) (DOTP) have been examined by high-resolution NMR spectroscopy. The proton spectra of the diamagnetic La(DOTP) 5- and Lu(DOTP) 5- complexes provide evidence for very rigid chelate structures with the ethylenediamine-containing chelate rings essentially locked into a single conformation at room temperature. The activation energy for ethylenediamine chelate ring interconversions in these complexes is approximately 100 kJ mol -1, considerably higher than that reported previously for the corresponding Ln(DOTA) - complexes (DOTA is the tetraacetate analog of DOTP). Lanthanide-induced shifts are reported for all 1H, 13C, and 31P nuclei in 11 Ln(DOTP) 5- complexes. The proton spectra of these complexes display unusually large lanthanide-induced shifts, one showing a spectrum in which the 1H resonances span 900 ppm. The contact and pseudocontact contributions to these shifts were separated using Reilley's temperature-independent method and the resulting pseudocontact lanthanide-induced NMR shifts were in excellent agreement with those calculated for a structure derived using MMX molecular modeling methods. The pseudocontact shifts provide evidence for Ln (DOTP) 5- chelates which have virtually identical structures along the lanthanide series, with the possible exception of Tm(DOTP) 5-.

Geraldes, Carlos F. G. C.; Sherry, A. Dean; Kiefer, Garry E.

13

23Na NMR study of Fibrobacter succinogenes S85: comparison of three chemical shift reagents and calculation of sodium concentration using ionophores.  

PubMed

In order to measure intracellular sodium concentrations in resting cells of Fibrobacter succinogenes S85 by (23)Na NMR spectrometry, two methodological aspects were studied. First, three different shift reagents (Dy(PPP(i))(7-)(2), Tm(DOTP)(5-), and Dy(TTHA)(3-)) were tested for their ability to separate internal and external (23)Na NMR resonances. Their toxicity toward F. succinogenes cells was evaluated by in vivo(13)C NMR experiments. Tm(DOTP)(5-) was found to be the most efficient shift reagent while being nontoxic. Second, a new methodology was developed to calculate intracellular sodium concentration in F. succinogenes by using ionophores. This approach avoided the problem of intracellular volume measurement and that of sodium visibility determination. PMID:12123653

Delort, Anne-Marie; Gaudet, Geneviève; Forano, Evelyne

2002-07-15

14

In vivo measurements of intra- and extracellular Na+ and water in the brain and muscle by nuclear magnetic resonance spectroscopy with shift reagent.  

PubMed Central

The introduction of new paramagnetic shift reagents in the nuclear magnetic resonance (NMR) method has made it possible to distinguish intra- and extracellular ions in tissues or organs in vitro. We measured the intra- and extracellular 23Na and 1H in vivo in the gerbil brain and skeletal muscle by NMR spectroscopy employing the shift reagent, dysprosium triethylenetetraminehexaacetate (Dy[TTHA]3-). Without Dy(TTHA)3-, the 23Na and 1H signals were seen only as single peaks, but gradual intravenous infusion of Dy(TTHA)3- separated these signals into two peaks, respectively. The unshifted peaks reflected the intracellular 23Na and 1H signals, while the shifted peaks reflected the extracellular signals. In the brain spectra, an additional small peak, which represented intravascular signals, was detected and its intensity increased after injection of papaverine hydrochloride. The present method is advantageous over the microelectrode technique because of its nondestructiveness and its capability for obtaining intra- and extracellular volume information from measurements of the 1H spectra, the peaks of which reflect the intra- and extracellular water amounts. The intracellular Na+ increase associating with increased cellular volume after ouabain in the muscle was clearly visualized by this method. The technique is clearly of use for physiological and pathophysiological studies of organs. PMID:3676441

Naritomi, H; Kanashiro, M; Sasaki, M; Kuribayashi, Y; Sawada, T

1987-01-01

15

Secret lanthanides.  

PubMed

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

Sturza, Cm

2014-09-15

16

Secret Lanthanides  

PubMed Central

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

Sturza, CM

2014-01-01

17

Ion-Pairing Interactions between Co(en)(3)(3+) and the (23)Na NMR Frequency Shift Reagent TmDOTP(5)(-).  

PubMed

Three new formulations of TmDOTP(5)(-) (DOTP(8)(-) = 1,4,7,10-tetraazacyclododecane-1,4,7,11-tetrakis(methylenephosphonate)) have been prepared in an effort to develop a low-osmolality form of the (23)Na frequency shift reagent (SR). Equally concentrated (0.32 M) solutions of (MegH)(4)HTmDOTP (Meg = N-methylglucamine or meglumine), Na(4)HTmDOTP, and [Co(en)(3)](4/3)HTmDOTP have solution osmolalities of 1245, 1040, and 707 mOsm/kg, respectively, comparable to the ionic and non-ionic gadolinium-based MRI contrast agent preparations in clinical use. An analysis of (23)Na and (59)Co frequency shifts induced by TmDOTP(5)(-) indicated that Co(en)(3)(3+) can form both 1:1 and 2:1 adducts with TmDOTP(5)(-) with (log) binding constants of 3.1 +/- 0.4 and 2.5 +/- 0.4, respectively. These values were comparable with those obtained by analysis of the (1)H frequency shifts observed for Co(en)(3)(3+) upon binding to HoDOTP(5)(-). The (1)H shifts of Co(en)(3)(3+) signals induced by YbDOTP(5)(-) at pH 7.4 were fitted best by a 1:1 binding model with a conditional binding constant of 3.1 +/- 0.2. The (59)Co and (1)H limiting frequency shifts of Co(en)(3)(3+) could be fitted with a dipolar shift model in which the Co atom of the Co(en)(3)(3+) cation is located 5.0 +/- 0.3 Å from the Ln atom of the LnDOTP(5)(-) chelate, and with an angle of 40 +/- 0.2 degrees between the Co-Ln vector and the 4-fold symmetry axis of the LnDOTP(5)(-) complex. Ion pairing of Co(en)(3)(3+) and TmDOTP(5)(-) was significant enough in both saline and human blood plasma to reduce the effectiveness of the (23)Na frequency SR. Comparisons between all formulations suggested that Na(4)HTmDOTP represents the best compromise of lower osmolality with minimal reduction of SR shift potency. PMID:11670028

Ren, Jimin; Springer, Charles S.; Sherry, A. Dean

1997-07-30

18

Method bacterial endospore quantification using lanthanide dipicolinate luminescence  

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

19

Luminescent lanthanide chelates and methods of use  

DOEpatents

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

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

1997-01-01

20

Lanthanide ion (III) complexes of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminophosphonate for dual biosensing of pH with chemical exchange saturation transfer (CEST) and biosensor imaging of redundant deviation in shifts (BIRDS).  

PubMed

Relaxivity-based magnetic resonance of phosphonated ligands chelated with gadolinium (Gd(3+) ) shows promise for pH imaging. However instead of monitoring the paramagnetic effect of lanthanide complexes on the relaxivity of water protons, biosensor (or molecular) imaging with magnetic resonance is also possible by detecting either the nonexchangeable or the exchangeable protons on the lanthanide complexes themselves. The nonexchangeable protons (e.g. -CHx , where 3???x???1) are detected using a three-dimensional chemical shift imaging method called biosensor imaging of redundant deviation in shifts (BIRDS), whereas the exchangeable protons (e.g. -OH or -NHy , where 2???y???1) are measured with chemical exchange saturation transfer (CEST) contrast. Here we tested the feasibility of BIRDS and CEST for pH imaging of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminophosphonate (DOTA-4AmP(8-) ) chelated with thulium (Tm(3+) ) and ytterbium (Yb(3+) ). BIRDS and CEST experiments show that both complexes are responsive to pH and temperature changes. Higher pH and temperature sensitivities are obtained with BIRDS for either complex when using the chemical shift difference between two proton resonances vs using the chemical shift of a single proton resonance, thereby eliminating the need to use water resonance as reference. While CEST contrast for both agents is linearly dependent on pH within a relatively large range (i.e. 6.3-7.9), much stronger CEST contrast is obtained with YbDOTA-4AmP(5-) than with TmDOTA-4AmP(5-) . In addition, we demonstrate the prospect of using BIRDS to calibrate CEST as new platform for quantitative pH imaging. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24801742

Huang, Yuegao; Coman, Daniel; Ali, Meser M; Hyder, Fahmeed

2014-05-01

21

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

2011-09-01

22

XPS analyses of lanthanides phosphates  

NASA Astrophysics Data System (ADS)

XPS measurements were performed on lanthanide orthophosphates LnPO 4 (Ln: La, Ce, Nd, Gd), and correlated with XRD and some EDS analyses. Single lanthanide phosphates LnPO 4 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)PO 4 and (La,Gd)PO 4, 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

23

Lanthanide-halide based humidity indicators  

DOEpatents

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

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

2008-01-01

24

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

SciTech Connect

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

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

1997-01-01

25

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

26

Paradigm shift from alkaline (earth) metals to early transition metals in fluoroorganometal chemistry: perfluoroalkyl titanocene(III) reagents prepared via not titanocene(II) but titanocene(III) species.  

PubMed

Perfluoroalkyl (RF) titanocene reagents [Cp2Ti(III)RF] synthesized via [Cp2Ti(III)Cl] rather than [Cp2Ti(II)] show new types of perfluoroalkylation reactions. The [Cp2Ti(III)RF] reagents exhibit a wide variety of reactivity with carbonyl compounds including esters and nitriles, and selectivities far higher than those reported for conventional RFLi and RFMgX reagents. PMID:24459023

Fujiu, Motohiro; Hashimoto, Ryota; Nakamura, Yuzo; Aikawa, Kohsuke; Ito, Shigekazu; Mikami, Koichi

2014-02-17

27

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

28

Thermolysis of lanthanide dithiocarbamate complexes  

SciTech Connect

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. - Graphical abstract: Polycrystalline lanthanide sulfide materials were formed at low temperatures using a single-source precursor based on the lanthanide dithiocarbamate complex.

Boncher, William L.; Regulacio, Michelle D. [Department of Chemistry, Georgetown University, Washington DC 20057 (United States); Stoll, Sarah L., E-mail: sls55@georgetown.ed [Department of Chemistry, Georgetown University, Washington DC 20057 (United States)

2010-01-15

29

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

30

Synthesis and characterisation of luminescent lanthanide dyes for solar energy conversion   

E-print Network

Lanthanide (III) complexes are used extensively in solar conversion devices, such as Luminescent Solar Concentrators (LSCs) and Luminescent Down-Shifting (LDS) for their peculiar characteristics of narrow band emission, ...

Congiu, Martina

2013-06-29

31

Luminescent macrocyclic lanthanide complexes  

DOEpatents

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

Raymond, Kenneth N; Corneillie, Todd M; Xu, Jide

2014-05-20

32

Luminescent macrocyclic lanthanide complexes  

DOEpatents

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

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

2012-05-08

33

Bifunctional organophosphorus liquid-liquid extraction reagents: development and applications  

SciTech Connect

American and Russian workers have evidenced great interest in the last decade in the potential application of certain neutral and acidic bifunctional organophosphorus compounds in solvent extraction processes. Triggering this interest is the ability of some carbamoylmethylenephosphorus (CMP) and carbamoylmethylenephosphine oxide (CMPO) compounds to extract trivalent actinides and lanthanides from strong HNO/sub 3/ (>1M) solutions, a property which distinguishes them from monofunctional organophosphorus reagents. Investigators at several US Department of Energy laboratories have concentrated on synthesis of novel CMP and CMPO reagents and on reactions and mechanisms involved in extraction of metal ions from aqueous nitrate media; application of selected CMP and CMPO reagents in solvent extraction and supported liquid membrane recovery of metal values from nuclear waste solutions have been proposed. This paper, based upon a book now in preparation, provides a brief overview of the current status of the development and application of bifunctional organophosphorus extractants. 42 references, 4 tables.

Schulz, W.W.; Navratil, J.D.

1984-03-13

34

Bifunctional organophosphorus liquid-liquid extraction reagents: development and applications  

SciTech Connect

American and Russian workers have evidenced great interest in the last decade in the potential application of certain neutral and acidic bifunctional organophosphorus compounds in solvent extraction processes. Triggering this interest is the ability of some carbamoylmethylenephosphorus (CMP) and carbamoylmethylenephosphine oxide (CMPO) compounds to extract trivalent actinides and lanthanides from strong HNO/sub 3/ (>1 M) solutions, a property which distinguishes them from monofunctional organophosphorus reagents. Investigators at several US Department of Energy laboratories have concentrated on synthesis of novel CMP and CMPO reagents and on reactions and mechanisms involved in extraction of metal ions from aqueous nitrate media; application of selected CMP and CMPO reagents in solvent extraction and supported liquid membrane recovery of metal values from nuclear waste solutions have been proposed. This paper, based upon a book now in preparation, provides a brief overview of the current status of the development and application of bifunctional organophosphorus extractants. 44 references, 4 tables.

Schulz, W.W.; Navratil, J.D.

1985-01-01

35

Luminescent lanthanide coordination polymers  

SciTech Connect

One-dimensional lanthanide coordination polymers with the formula Ln(isonicotinate){sub 3}(H{sub 2}O){sub 2} (Ln = Ce, Pr, Nd, Sm, Eu, Tb; 1a-f) were synthesized by treating nitrate or perchlorate salts of Ln(III) with 4-pyridinecarboxaldehyde under hydro(solvo)thermal conditions. Single-crystal and powder X-ray diffraction studies indicate that these lanthanide coordination polymers adopt two different structures. While Ce(III), Pr(III), and Nd(III) complexes adopt a chain structure with alternating Ln-(carboxylate){sub 2}-Ln and Ln-(carboxylate){sub 4}-Ln linkages, Sm(III), Eu(III), and Tb(III) complexes have a doubly carboxylate-bridged infinite-chain structure with one chelating carboxylate group on each metal center. In both structures, the lanthanide centers also bind to two water molecules to yield an eight-coordinate, square antiprismatic geometry. The pyridine nitrogen atoms of the isonicotinate groups do not coordinate to the metal centers in these lanthanide(III) complexes; instead, they direct the formation of Ln(III) coordination polymers via hydrogen bonding with coordinated water molecules. Photoluminescence measurements show that Tb(isonicotinate){sub 3}(H{sub 2}O){sub 2} is highly emissive at room temperature with a quantum yield of {approximately}90%. These results indicate that highly luminescent lanthanide coordination polymers can be assembled using a combination of coordination and hydrogen bonds. Crystal data for 1a: monoclinic space group P2{sub 1}/c, a = 9.712(2) {angstrom}, b = 19.833(4) {angstrom}, c = 11.616(2) {angstrom}, {beta} = 111.89(3){degree}, Z = 4. Crystal data for 1f: monoclinic space group C2/c, a = 20.253(4) {angstrom}, b = 11.584(2) {angstrom}, c = 9.839(2) {angstrom}, {beta} = 115.64(3){degree}, Z = 8.

Ma, L.; Evans, O.R.; Foxman, B.M.; Lin, W.

1999-12-13

36

Advancing the scientific basis of trivalent actinide-lanthanide separations  

SciTech Connect

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

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

2013-07-01

37

Reference Reagents Group  

Cancer.gov

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

38

Aromatic triamide-lanthanide complexes  

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.

2013-10-08

39

Reagents, Compositions, Weight Loss  

NSDL National Science Digital Library

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

Perkins, Dexter

40

Flavonoids as Analytical Reagents  

Microsoft Academic Search

Compounds from the flavonoid family, while exhibiting a wide range of biological effects, are interesting reagents for analytical purposes as well. They form complexes with several p-, d-, and f-electron metals, which could be employed in the determination of these metal ions in different kinds of samples by various techniques. This article presents and discusses the application of flavonoid compounds

Krystyna Pyrzynska; Anna P?kal

2011-01-01

41

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

42

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

PubMed

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

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

2013-04-01

43

Trivalent Actinide and Lanthanide Separations by Dialkyl?Substituted Diphosphonic Acids  

Microsoft Academic Search

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

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

2005-01-01

44

Calibration beads containing luminescent lanthanide ion complexes  

EPA Science Inventory

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

45

Actinide Lanthanide Separation Process – ALSEP  

SciTech Connect

Separation of the minor actinides (Am, Cm) from the lanthanides at an industrial scale remains a significant technical challenge for closing the nuclear fuel cycle. To increase the safety of used nuclear fuel (UNF) reprocessing, as well as reduce associated costs, a novel solvent extraction process has been developed. The process allows for partitioning minor actinides, lanthanides and fission products following uranium/plutonium/neptunium removal; minimizing the number of separation steps, flowsheets, chemical consumption, and waste. This new process, Actinide Lanthanide SEParation (ALSEP), uses an organic solvent consisting of a neutral diglycolamide extractant, either N,N,N',N'-tetra(2 ethylhexyl)diglycolamide (T2EHDGA) or N,N,N',N'-tetraoctyldiglycolamide (TODGA), and an acidic extractant 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]), dissolved in an aliphatic diluent (e.g. n-dodecane). The An/Ln co-extraction is conducted from moderate-to-strong nitric acid, while the selective stripping of the minor actinides from the lanthanides is carried out using a polyaminocarboxylic acid/citrate buffered solution at pH anywhere between 3 and 4.5. The extraction and separation of the actinides from the fission products is very effective in a wide range of HNO3 concentrations and the minimum separation factors for lanthanide/Am exceed 30 for Nd/Am, reaching > 60 for Eu/Am under some conditions. The experimental results presented here demonstrate the great potential for a combined system, consisting of a neutral extractant such as T2EHDGA or TODGA, and an acidic extractant such as HEH[EHP], for separating the minor actinides from the lanthanides.

Gelis, Artem V.; Lumetta, Gregg J.

2014-01-29

46

New versatile staining reagents for biological transmission electron microscopy that substitute for uranyl acetate.  

PubMed

Aqueous uranyl acetate has been extensively used as a superb staining reagent for transmission electron microscopy of biological materials. However, recent regulation of nuclear fuel material severely restricts its use even for purely scientific purposes. Since uranyl salts are hazardous due to biological toxicity and remaining radioactivity, development of safe and non-radioactive substitutes is greatly anticipated. We examined two lanthanide salts, samarium triacetate and gadolinium triacetate, and found that 1-10% solution of these reagents was safe but still possess excellent capability for staining thin sections of plastic-embedded materials of animal and plant origin. Although post-fixation with osmium tetroxide was essential for high-contrast staining, post-staining with lead citrate could be eliminated if a slow-scan CCD camera is available for observation. These lanthanide salts can also be utilized as good negative-staining reagents to study supramolecular architecture of biological macromolecules. They were not as effective as a fixative of protein assembly, reflecting the non-hazardous nature of the reagents. PMID:22146677

Nakakoshi, Masamichi; Nishioka, Hideo; Katayama, Eisaku

2011-12-01

47

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, that can identify the major leukocy...

48

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...

49

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

50

21 CFR 866.4100 - Complement reagent.  

Code of Federal Regulations, 2011 CFR

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

2011-04-01

51

21 CFR 866.4100 - Complement reagent.  

Code of Federal Regulations, 2012 CFR

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

2012-04-01

52

21 CFR 866.4100 - Complement reagent.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

53

21 CFR 866.4100 - Complement reagent.  

Code of Federal Regulations, 2014 CFR

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

2014-04-01

54

21 CFR 866.4100 - Complement reagent.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

55

Surface ionization of the lanthanides  

Microsoft Academic Search

The surface ionization of Lanthanides: Ce, Pr, Nd, Sm and Eu, and its fluctuations (noises) have been studied using a double filament ion source in a 90° magnetic mass spectrometer. Using the Saha-Langmuir equation there were measured ionization potentials of LnO molecules as the dissociation products of the oxides Ln2O3 (the Ln symbol denotes the arbitrary rare earth elements: Ce,

L. G?adyszewski; G. G?adyszewski; T. Pie?kos

2004-01-01

56

Electron transfer processes in double lanthanide activated YPO 4  

Microsoft Academic Search

This work reviews electron transfer processes in double lanthanide doped YPO4 studied using a diversity of optical techniques. The aim is to identify those transfer processes and to relate them with the location of lanthanide electron donor and lanthanide electron acceptor states within the bandgap of YPO4. Electron transfer from the valence band to a trivalent lanthanide impurity or to

P. Dorenbos; A. J. J. Bos; N. R. J. Poolton

2011-01-01

57

Investigation of dissociation enhanced lanthanide fluoroimmunoassay as an alternative screening test for veterinary drug residues.  

PubMed

Both the number of drugs used in veterinary medicine and the diversity of procedures employed to detect their residues are ever increasing. Many laboratories that carry out such testing have employed a variety of immunoassays to serve as rapid screening tests. Owing to the high sensitivity, good reproducibility and availability of multi-analyte assays dissociation enhanced time-resolved fluorescence immunoassay (dissociation enhanced lanthanide fluoroimmunoassay, DELFIA) kits have become a market leader in the human clinical field. No commercial DELFIA kits are presently available for veterinary drug analysis. A DELFIA method was developed for the quantitative analysis of residues of medroxyprogesterone (MP) in bovine bile. Commercially available DELFIA reagents were used in a microtitre assay format. Within- and between-assay sr values (relative standard deviation) were 4.2-9.9 and 5.1-8.5%, respectively. Detection limits were calculated (mean + 3 s of a known negative population) as being 0.52 and 4.91 micrograms l-1 for male and female animals, respectively. A second study was carried out to optimize the labelling of haptens with a range of lanthanide metals. Purification of the hapten-lanthanide conjugates produced was achieved using fast protein liquid chromatography. Sensitive standard curves were produced for nortestosterone and diethylstilbestrol (curve mid-points of 30 and 40 pg, respectively). By using two different lanthanide labels (Eu and Tb) the simultaneous measurement of these compounds in a single assay system was achieved. Use of a third lanthanide label (Sm) yielded a product of low signal intensity and sensitivity. PMID:7879855

Elliott, C T; Francis, K S; McCaughey, W J

1994-12-01

58

Exploring Crown Ethers as Shift Reagents for Ion Mobility Spectrometry  

E-print Network

.; Valentine, S. J.; Counterman, A. E.; Clemmer, D. E. Anal. Chem. 1999, 71, 291-301. (2) Valentine, S. J.; Schultz, A. J. Anal. Chem. 2000, 72, 3965-3971. (5) Wu, C.; Siems, W. F.; Klasmeier, J.; Hill, H. H., Jr. Anal. Chem. 2000, 72, 391. (6) Guevremont, R.; Barnett, D. A.; Purves, R. W.; Vandermey, J. Anal. Chem

Clemmer, David E.

59

Chemical Amplification with Encapsulated Reagents  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

60

Separation of actinides from lanthanides  

DOEpatents

An organic extracting solution and an extraction method useful for separating elements of the actinide series of the periodic table from elements of the lanthanide series, where both are in trivalent form. 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

61

Separation of actinides from lanthanides  

DOEpatents

An organic extracting solution and an extraction method useful for separating elements of the actinide series of the periodic table from elements of the lanthanide series, where both are in trivalent form 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

62

Stain Reagent Reversible Stain Kits  

E-print Network

GelCode ® Blue Stain Reagent GelCode ® SilverSNAP TM Stain GelCode ® E-Zinc TM Reversible Stain ease of use and relatively good sensitivity. Although alternative methods, such as silver staining,1 as a colloidal suspension. The colloidal particles do not penetrate the gel, but the dye molecules are extracted

Lebendiker, Mario

63

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

64

[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

65

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

PubMed

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

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

2012-10-01

66

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

67

21 CFR 866.3240 - Equine encephalomyelitis virus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Equine encephalomyelitis virus serological reagents. 866.3240...866.3240 Equine encephalomyelitis virus serological reagents. (a) Identification. Equine encephalomyelitis virus serological reagents are...

2010-04-01

68

21 CFR 866.3360 - Lymphocytic choriomeningitis virus serological reagents.  

Code of Federal Regulations, 2010 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...

2010-04-01

69

21 CFR 866.3240 - Equine encephalomyelitis virus serological reagents.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 false Equine encephalomyelitis virus serological reagents. 866.3240...866.3240 Equine encephalomyelitis virus serological reagents. (a) Identification. Equine encephalomyelitis virus serological reagents are...

2014-04-01

70

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

71

21 CFR 866.3240 - Equine encephalomyelitis virus serological reagents.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Equine encephalomyelitis virus serological reagents. 866.3240...866.3240 Equine encephalomyelitis virus serological reagents. (a) Identification. Equine encephalomyelitis virus serological reagents are...

2011-04-01

72

21 CFR 866.3240 - Equine encephalomyelitis virus serological reagents.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Equine encephalomyelitis virus serological reagents. 866.3240...866.3240 Equine encephalomyelitis virus serological reagents. (a) Identification. Equine encephalomyelitis virus serological reagents are...

2012-04-01

73

21 CFR 866.3240 - Equine encephalomyelitis virus serological reagents.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Equine encephalomyelitis virus serological reagents. 866.3240...866.3240 Equine encephalomyelitis virus serological reagents. (a) Identification. Equine encephalomyelitis virus serological reagents are...

2013-04-01

74

21 CFR 866.3360 - Lymphocytic choriomeningitis virus serological reagents.  

Code of Federal Regulations, 2011 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...

2011-04-01

75

21 CFR 866.3360 - Lymphocytic choriomeningitis virus serological reagents.  

Code of Federal Regulations, 2014 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...

2014-04-01

76

21 CFR 866.3360 - Lymphocytic choriomeningitis virus serological reagents.  

Code of Federal Regulations, 2012 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...

2012-04-01

77

21 CFR 866.3740 - Streptococcus spp. serological reagents.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Streptococcus spp. serological reagents. 866...Serological Reagents § 866.3740 Streptococcus spp. serological reagents. (a) Identification. Streptococcus spp. serological...

2013-04-01

78

21 CFR 866.3740 - Streptococcus spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Streptococcus spp. serological reagents. 866...Serological Reagents § 866.3740 Streptococcus spp. serological reagents. (a) Identification. Streptococcus spp. serological...

2010-04-01

79

21 CFR 866.3740 - Streptococcus spp. serological reagents.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Streptococcus spp. serological reagents. 866...Serological Reagents § 866.3740 Streptococcus spp. serological reagents. (a) Identification. Streptococcus spp. serological...

2014-04-01

80

21 CFR 866.3740 - Streptococcus spp. serological reagents.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Streptococcus spp. serological reagents. 866...Serological Reagents § 866.3740 Streptococcus spp. serological reagents. (a) Identification. Streptococcus spp. serological...

2011-04-01

81

21 CFR 866.3740 - Streptococcus spp. serological reagents.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Streptococcus spp. serological reagents. 866...Serological Reagents § 866.3740 Streptococcus spp. serological reagents. (a) Identification. Streptococcus spp. serological...

2012-04-01

82

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

SciTech Connect

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

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

2009-12-01

83

Lanthanide-tagged proteins – An illuminating partnership  

E-print Network

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

Imperiali, Barbara

84

Mitochondrially targeted antioxidants and thiol reagents  

Microsoft Academic Search

Mitochondrial oxidative damage and dysfunction contributes to a number of cell pathologies. To investigate how this damage affects cell function we have developed mitochondrially targeted antioxidants and thiol reagents by covalently linking them to lipophilic cations. The cation drives the selective accumulation of these reagents into mitochondria within cells where the antioxidants decrease oxidative damage and the thiol reagents enable

Carolyn V. Coulter; Geoffrey F. Kelso; Tsu-Kung Lin; Robin A. J. Smith; Michael P. Murphy

2000-01-01

85

Pulmonary toxicity of stable and radioactive lanthanides.  

PubMed

The pulmonary toxicity of inhaled lanthanides has been the subject of debate. In question have been the relative contributions of radioactive vs. stable elements in the development of lanthanide-associated progressive pulmonary interstitial fibrosis. The central question of this debate is: Are lanthanide dusts that are devoid of radioactive contaminants capable of producing progressive pulmonary disease, or are lanthanide-induced lesions more appropriately termed "benign pneumoconioses"? This paper examines the epidemiologic and experimental record in order to answer the above question. It is clear from the available data that significant pathogenic potential of inhaled lanthanides exists and is related to the type and physicochemical form of the material inhaled and to the dose and duration of exposure. Contamination of the dust with radioactive materials may accelerate and enhance the pathologic response, depending on the form and dose of radioactivity encountered. Nevertheless, there is little evidence to suggest that the level of radioactive contamination of occupationally encountered lanthanide dusts is sufficient to be included as a risk factor for pulmonary disease. Thus, the pulmonary syndrome induced by stable rare earths includes progressive pulmonary fibrosis and should not be referred to as "benign pneumoconiosis." PMID:1955325

Haley, P J

1991-12-01

86

Multicolor tuning of lanthanide-doped nanoparticles by single wavelength excitation.  

PubMed

Lanthanide-doped nanoparticles exhibit unique luminescent properties, including large Stokes shift, sharp emission bandwidth, high resistance to optical blinking, and photobleaching, as well as the unique ability to convert long-wavelength stimulation into short-wavelength emission. These attributes are particularly needed for developing luminescent labels as alternatives to organic fluorophores and quantum dots. In recent years, the well-recognized advantages of upconversion nanocrystals as biomarkers have been manifested in many important applications, such as highly sensitive molecular detection and autofluorescence-free cell imaging. However, their potential in multiplexed detection and multicolor imaging is rarely exploited, largely owing to the research lagging on multicolor tuning of these particles. Lanthanide doping typically involves an insulating host matrix and a trace amount of lanthanide dopants embedded in the host lattice. The luminescence observed from these doped crystalline materials primarily originates from electronic transitions within the [Xe]4f(n) configuration of the lanthanide dopants. Thus a straightforward approach to tuning the emission is to dope different lanthanide activators in the host lattice. Meanwhile, the host lattice can exert a crystal field around the lanthanide dopants and sometimes may even exchange energy with the dopants. Therefore, the emission can also be modulated by varying the host materials. Recently, the advance in synthetic methods toward high quality core-shell nanocrystals has led to the emergence of new strategies for emission modulation. These strategies rely on precise control over either energy exchange interactions between the dopants or energy transfer involving other optical entities. To provide a set of criteria for future work in this field, we attempt to review general and emerging strategies for tuning emission spectra through lanthanide doping. With significant progress made over the past several years, we now are able to design and fabricate nanoparticles displaying tailorable optical properties. In particular, we show that, by rational control of different combinations of dopants and dopant concentration, a wealth of color output can be generated under single-wavelength excitation. Strikingly, unprecedented single-band emissions can be obtained by careful selection of host matrices. By incorporating a set of lanthanide ions at defined concentrations into different layers of a core-shell structure, the emission spectra of the particles are largely expanded to cover almost the entire visible region, which is hardly accessible by conventional bulk phosphors. Importantly, we demonstrate that an inert-shell coating provides the particles with stable emission against perturbation in surrounding environments, paving the way for their applications in the context of biological networks. PMID:24611606

Wang, Feng; Liu, Xiaogang

2014-04-15

87

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

88

21 CFR 866.3400 - Parainfluenza virus serological reagents.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 false Parainfluenza virus serological reagents. 866.3400 Section...Reagents § 866.3400 Parainfluenza virus serological reagents. (a) Identification. Parainfluenza virus serological reagents are devices...

2011-04-01

89

21 CFR 866.3400 - Parainfluenza virus serological reagents.  

Code of Federal Regulations, 2014 CFR

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

2014-04-01

90

21 CFR 866.3380 - Mumps virus serological reagents.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Mumps virus serological reagents. 866.3380 Section...Serological Reagents § 866.3380 Mumps virus serological reagents. (a) Identification. Mumps virus serological reagents consist of...

2011-04-01

91

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

92

21 CFR 866.3400 - Parainfluenza virus serological reagents.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 false Parainfluenza virus serological reagents. 866.3400 Section...Reagents § 866.3400 Parainfluenza virus serological reagents. (a) Identification. Parainfluenza virus serological reagents are devices...

2010-04-01

93

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. 866.3940 ...Serological Reagents § 866.3940 West Nile virus serological reagents. (a) Identification. West Nile virus serological reagents are devices...

2013-04-01

94

21 CFR 866.3940 - West Nile virus serological reagents.  

Code of Federal Regulations, 2014 CFR

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

2014-04-01

95

21 CFR 866.3380 - Mumps virus serological reagents.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Mumps virus serological reagents. 866.3380 Section...Serological Reagents § 866.3380 Mumps virus serological reagents. (a) Identification. Mumps virus serological reagents consist of...

2012-04-01

96

21 CFR 866.3400 - Parainfluenza virus serological reagents.  

Code of Federal Regulations, 2012 CFR

... 2012-04-01 false Parainfluenza virus serological reagents. 866.3400 Section...Reagents § 866.3400 Parainfluenza virus serological reagents. (a) Identification. Parainfluenza virus serological reagents are devices...

2012-04-01

97

21 CFR 866.3380 - Mumps virus serological reagents.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Mumps virus serological reagents. 866.3380 Section...Serological Reagents § 866.3380 Mumps virus serological reagents. (a) Identification. Mumps virus serological reagents consist of...

2013-04-01

98

21 CFR 866.3336 - John Cunningham Virus serological reagents.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 false John Cunningham Virus serological reagents. 866.3336 ...Reagents § 866.3336 John Cunningham Virus serological reagents. (a) Identification. John Cunningham Virus serological reagents are devices...

2014-04-01

99

21 CFR 866.3380 - Mumps virus serological reagents.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Mumps virus serological reagents. 866.3380 Section...Serological Reagents § 866.3380 Mumps virus serological reagents. (a) Identification. Mumps virus serological reagents consist of...

2014-04-01

100

21 CFR 866.3380 - Mumps virus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Mumps virus serological reagents. 866.3380 Section...Serological Reagents § 866.3380 Mumps virus serological reagents. (a) Identification. Mumps virus serological reagents consist of...

2010-04-01

101

21 CFR 866.3550 - Salmonella spp. serological reagents.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Salmonella spp. serological reagents. 866...Serological Reagents § 866.3550 Salmonella spp. serological reagents. (a) Identification. Salmonella spp. serological reagents...

2011-04-01

102

21 CFR 866.3550 - Salmonella spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Salmonella spp. serological reagents. 866...Serological Reagents § 866.3550 Salmonella spp. serological reagents. (a) Identification. Salmonella spp. serological reagents...

2010-04-01

103

21 CFR 866.3550 - Salmonella spp. serological reagents.  

Code of Federal Regulations, 2012 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

104

21 CFR 606.65 - Supplies and reagents.  

Code of Federal Regulations, 2014 CFR

...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 reagents that do not bear an expiration date...

2014-04-01

105

21 CFR 606.65 - Supplies and reagents.  

Code of Federal Regulations, 2013 CFR

...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 reagents that do not bear an expiration date...

2013-04-01

106

21 CFR 606.65 - Supplies and reagents.  

Code of Federal Regulations, 2012 CFR

...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 reagents that do not bear an expiration date...

2012-04-01

107

21 CFR 606.65 - Supplies and reagents.  

Code of Federal Regulations, 2010 CFR

...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 reagents that do not bear an expiration date...

2010-04-01

108

21 CFR 606.65 - Supplies and reagents.  

Code of Federal Regulations, 2011 CFR

...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 reagents that do not bear an expiration date...

2011-04-01

109

21 CFR 864.8540 - Red cell lysing reagent.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Red cell lysing reagent. 864.8540 Section 864... Hematology Reagents § 864.8540 Red cell lysing reagent. (a) Identification. A red cell lysing reagent is a device used to...

2012-04-01

110

21 CFR 864.8540 - Red cell lysing reagent.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Red cell lysing reagent. 864.8540 Section 864... Hematology Reagents § 864.8540 Red cell lysing reagent. (a) Identification. A red cell lysing reagent is a device used to...

2011-04-01

111

21 CFR 864.8540 - Red cell lysing reagent.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Red cell lysing reagent. 864.8540 Section 864... Hematology Reagents § 864.8540 Red cell lysing reagent. (a) Identification. A red cell lysing reagent is a device used to...

2014-04-01

112

21 CFR 864.8540 - Red cell lysing reagent.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

113

21 CFR 864.8540 - Red cell lysing reagent.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Red cell lysing reagent. 864.8540 Section 864... Hematology Reagents § 864.8540 Red cell lysing reagent. (a) Identification. A red cell lysing reagent is a device used to...

2013-04-01

114

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

115

Renewable-reagent electrochemical sensor  

DOEpatents

A new electrochemical probe(s) design allowing for continuous (renewable) reagent delivery is described. 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). 19 figs.

Wang, J.; Olsen, K.B.

1999-08-24

116

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

117

Physical characteristics of lanthanide complexes that act as magnetization transfer (MT) contrast agents  

NASA Astrophysics Data System (ADS)

Rapid water exchange is normally considered a prerequisite for efficient Gd 3+-based MRI contrast agents. Yet recent measures of exchange rates in some Gd 3+ complexes have shown that water exchange can become limiting when such complexes are attached to larger macromolecular structures. A new class of lanthanide complexes that display unusually slow water exchange (bound water lifetimes ( ?M298) > 10 ?s) has recently been reported. This apparent disadvantage may be taken advantage of by switching the metal ion from gadolinium(III) to a lanthanide that shifts the bound water resonance substantially away from bulk water. Given appropriate water exchange kinetics, one can then alter the intensity of the bulk water signal by selective presaturation of this highly shifted, Ln3+-bound water resonance. This provides the basis of a new method to alter MR image contrast in tissue. We have synthesized a variety of DOTA-tetra(amide) ligands to evaluate as potential magnetization transfer (MT) contrast agents and found that the bound water lifetimes in these complexes are sensitive to both ligand structure (a series of Eu 3+ complexes have ?M298 values that range from 1 to 1300 ?s) and the identity of the paramagnetic Ln3+ cation (from 3 to 800 ?s for a single ligand). This demonstrates that it may be possible either to fine-tune the ligand structure or to select proper lanthanide cation to create an optimal MT agent for any clinical imaging field.

Zhang, Shanrong; Sherry, A. Dean

2003-02-01

118

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

119

Polyborylated reagents for modern organic synthesis  

PubMed Central

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

SHIMIZU, Masaki; HIYAMA, Tamejiro

2008-01-01

120

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

121

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

122

Renewable Reagent Fiber Optic Based Ammonia Sensor  

NASA Astrophysics Data System (ADS)

Many fiber optic based chemical sensors have been described which rely on a reagent chemistry fixed at the fiber endface to provide analyte specificity. In such systems, problems involving probe-to-probe reproducibility, reagent photolability and reagent leaching are frequently encountered. As a result, calibration and standardization of these sensors becomes difficult or impossible and thus inhibits their application for long term in situ chemical monitoring. Many of these problems can be addressed and several additional advantages gained by continuously renewing the reagent chemistry. To illustrate this concept, a fiber optic ammonia sensor is described in which the reagent is delivered under direct control to a sensing volume of approximately 400 nanoliters located at the probe tip. Using an acid-base indicator (bromothymol blue) as the reagent, the sample ammonia concentrations are related to modulations in light intensity with a lower limit of detection of 10 ppb. The sensor performance was studied with respect to reagent pH, concentration and reagent delivery rate. Compared with previous fiber optic ammonia sensors, the ability to reproducibly renew the reagent has resulted in improvements with respect to response and return times, probe-to-probe reproducibility, probe lifetime and flexibility of use.

Berman, Richard J.; Burgess, Lloyd W.

1990-02-01

123

Structural biology of the lanthanides-mining rare earths in the Protein Data Bank.  

PubMed

With its about 100,000 three-dimensional structures, the Protein Data Bank is a copious source of information: it contains also some hundreds of structures of macromolecules complexed with lanthanide cations, which are examined here. These cations, which are found in a wide variety of protein types, were introduced to determine the structures, by exploiting their anomalous dispersion (in crystallographic studies, where they are also used as crystallization additives) or the paramagnetic pseudocontact shifts (in NMR analyses). The coordination numbers in the first coordination sphere are very variable, though they tend to be close to those that are observed in small molecules or in water solution. The coordination polyhedra are also quite variable as it can be expected for large cations. Interestingly, lanthanide cations are frequently observed in packing bridges between symmetry equivalent molecules in crystals, where they tend to form polynuclear complexes, with up to seven cations bridged by water/hydroxide ligands. PMID:25528480

Djinovic-Carugo, Kristina; Carugo, Oliviero

2015-02-01

124

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

125

LANTHANIDE-BASED IMAGING OF PROTEIN-PROTEIN INTERACTIONS IN LIVE CELLS  

PubMed Central

In order to deduce the molecular mechanisms of biological function, it is necessary to monitor changes in the sub-cellular location, activation and interaction of proteins within living cells in real time. Förster resonance energy transfer (FRET)-based biosensors that incorporate genetically encoded, fluorescent proteins permit high spatial resolution imaging of protein–protein interactions or protein conformational dynamics. However, non-specific fluorescence background often obscures small FRET signal changes, and intensity-based biosensor measurements require careful interpretation and several control experiments. These problems can be overcome by using lanthanide (Tb(III) or Eu(III)) complexes as donors and green fluorescent protein (GFP) or other conventional fluorophores as acceptors. Essential features of this approach are the long-lifetime (~ms) luminescence of Tb(III) complexes and time-gated luminescence microscopy. This allows pulsed excitation followed by a brief delay that eliminates nonspecific fluorescence before detection of Tb(III)-to-GFP emission. The challenges of intracellular delivery, selective protein labeling, and time-gated imaging of lanthanide luminescence are presented, and recent efforts to investigate the cellular uptake of lanthanide probes are reviewed. Data is presented showing that conjugation to arginine-rich, cell penetrating peptides (CPPs) can be used as a general strategy for cellular delivery of membrane impermeable lanthanide complexes. A heterodimer of a luminescent Tb(III) complex, Lumi4, linked to trimethoprim (TMP) and conjugated to nonaarginine via a reducible disulfide linker rapidly (~10 min) translocates into the cytoplasm of Maden Darby canine kidney cells from culture medium. With this reagent, the intracellular interaction between GFP fused to FK506 binding protein 12 (GFP-FKBP12) and the rapamycin binding domain of mTOR fused to Escherichia coli dihydrofolate reductase (FRB-eDHFR) was imaged at high signal-to-noise ratio with fast (1–3 s) image acquisition using a time-gated luminescence microscope. The data reviewed and presented here show that lanthanide biosensors enable fast, sensitive and technically simple imaging of protein-protein interactions in live cells. PMID:24144069

Rajendran, Megha; Yapici, Engin; Miller, Lawrence W.

2013-01-01

126

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...

127

Eriochrome Black T as a post-column reagent for the ion chromatographic determination of rare earths.  

PubMed

The use of Eriochrome Black T in an alkaline, 40% methanol solution was found to be appropriate as post-column reagent for the determination of rare earths by ion chromatography. Detection of individual lanthanides and lanthanum was carried out at 512 nm and 650 nm after separation by dynamic cation exchange chromatography with gradient elution on C18 column and employing a solution containing alpha-hydroxyisobutiric acid/sodium octanesulfonate at pH 3.8 as eluent. The effect of the presence of micelles in the post-column reagent was studied. Sensitivities obtained by the addition of the cationic surfactants cetylpyridinium chloride (CPC) and hexadecyltrimethylammonium bromide (CTAB) were lower than those measured without surfactant addition. In some cases, the signal was totally suppressed. No change in sensitivity was observed with non-ionic (Triton X-100) or anionic (sodium dodecylsulphate, SDS) surfactants but a slight improvement in the baseline noise was observed with the SDS. An evaluation of the influence of chemical and operational variables on the post column reaction (PCR) reagent was carried out either by spectrophotometric tests or by chromatographic experiments. A comparison was performed between three PCR reagents: Eriochrome Black T and xylenol orange in the presence of a cationic surfactant and arsenazo III. Calibration response was linear up to an analyte concentration of 5.0 micrograms ml-1. Absolute detection limits lower than 7 and 17 ng were obtained at the detection wavelengths of 650 nm and 512 nm respectively, for all the natural lanthanides and lanthanum. PMID:10514976

Gettar, R T; Gautier, E A; Servant, R E; Batistoni, D A

1999-09-01

128

Thermal decompositions of heavy lanthanide aconitates  

Microsoft Academic Search

The conditions of thermal decomposition of Tb(III), Dy, Ho, Er, Tm, Yb and Lu aconitates have been studied. On heating, the aconitates of heavy lanthanides lose crystallization water to yield anhydrous salts, which are then transformed into oxides. The aconitate of Tb(III) decomposes in two stages. First, the complex undergoes dehydration to form the anhydrous salt, which next decomposes directly

W. Brzyska; W. O?ga

1982-01-01

129

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

130

Tendency of the Nephelauxetic Effect to Vary in a Series of Lanthanide Complexes with Allyl Acetoacetate  

NASA Astrophysics Data System (ADS)

The complexation of allyl acetoacetate with Pr3+, Nd3+, Ho3+, Er3+, and Tm3+ in aqueous solution was studied by electronic absorption spectroscopy. It was shown that allyl acetoacetate at pH 5.50 formed 1:1 and 1:2 complexes with the lanthanide ions depending on the reagent ratio. Intensity parameters ?? in addition to bond parameters using the free ions as comparative standards were calculated for the 1:2 complexes. It was established that the nephelauxetic ratio ? increased smoothly and approached unity in the order Pr3+ < Nd3+ < Ho3+ < Er3+ < Tm3+. Such variation was explained in the framework of covalent and polarization models.

Mishchenko, A. M.; Trunova, E. K.; Berezhnytskaya, A. S.; Rogovtsov, A. A.

2015-01-01

131

Extraction equilibria of rare earths by a new reagent (2-ethylhexyl-3-pentadecylphenyl) phosphoric acid.  

PubMed

A new reagent (2-ethylhexyl-3-pentadecylphenyl) phosphoric acid (EPPA = HR) was synthesized from cardanol (I, 37300-39-5) and was used to investigate the extraction behaviour of lanthanum(III), europium(III) and lutetium(III) from hydrochloric acid solutions. The species extracted were found to be Ln(HR(2))(3) (where Ln = La(III) or Eu(III) or Lu(III)). The extraction behaviour of the above lanthanides has also been compared with yttrium and other rare earths. It was observed that the extraction increases with increase in atomic number of rare earths. In addition, the extraction efficiency of EPPA has also been compared with well known acidic organophosphorus extractants like di-2-ethylhexyl phosphoric acid (DEHPA), 2-ethylhexyl-mono-2-ethylhexyl phosphoric acid (EHEHPA). PMID:18965945

Sreelatha, S; Rao, T P; Narayanan, C S; Damodaran, A D

1994-03-01

132

21 CFR 660.20 - Blood Grouping Reagent.  

Code of Federal Regulations, 2012 CFR

... 7 2012-04-01 2012-04-01 false Blood Grouping Reagent. 660.20 Section 660...FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Blood Grouping Reagent § 660.20 Blood Grouping Reagent. (a) Proper name and...

2012-04-01

133

21 CFR 660.20 - Blood Grouping Reagent.  

Code of Federal Regulations, 2011 CFR

... 7 2011-04-01 2010-04-01 true Blood Grouping Reagent. 660.20 Section 660...FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Blood Grouping Reagent § 660.20 Blood Grouping Reagent. (a) Proper name and...

2011-04-01

134

21 CFR 660.20 - Blood Grouping Reagent.  

Code of Federal Regulations, 2013 CFR

... 7 2013-04-01 2013-04-01 false Blood Grouping Reagent. 660.20 Section 660...FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Blood Grouping Reagent § 660.20 Blood Grouping Reagent. (a) Proper name and...

2013-04-01

135

21 CFR 660.20 - Blood Grouping Reagent.  

Code of Federal Regulations, 2014 CFR

... 7 2014-04-01 2014-04-01 false Blood Grouping Reagent. 660.20 Section 660...FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Blood Grouping Reagent § 660.20 Blood Grouping Reagent. (a) Proper name and...

2014-04-01

136

21 CFR 866.3480 - Respiratory syncytial virus serological reagents.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Respiratory syncytial virus serological reagents. 866.3480... § 866.3480 Respiratory syncytial virus serological reagents. (a) Identification. Respiratory syncytial virus serological reagents are devices...

2012-04-01

137

21 CFR 866.3480 - Respiratory syncytial virus serological reagents.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Respiratory syncytial virus serological reagents. 866.3480... § 866.3480 Respiratory syncytial virus serological reagents. (a) Identification. Respiratory syncytial virus serological reagents are devices...

2011-04-01

138

21 CFR 866.3480 - Respiratory syncytial virus serological reagents.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 false Respiratory syncytial virus serological reagents. 866.3480... § 866.3480 Respiratory syncytial virus serological reagents. (a) Identification. Respiratory syncytial virus serological reagents are devices...

2014-04-01

139

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

140

21 CFR 866.3480 - Respiratory syncytial virus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Respiratory syncytial virus serological reagents. 866.3480... § 866.3480 Respiratory syncytial virus serological reagents. (a) Identification. Respiratory syncytial virus serological reagents are devices...

2010-04-01

141

21 CFR 660.20 - Blood Grouping Reagent.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

142

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

143

21 CFR 1271.210 - Supplies and reagents.  

Code of Federal Regulations, 2010 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) REGULATIONS...BY THE FOOD AND DRUG ADMINISTRATION HUMAN CELLS, TISSUES, AND CELLULAR AND TISSUE-BASED...vendor of the supply or reagent. (b) Reagents . Reagents used in...

2010-04-01

144

21 CFR 864.8100 - Bothrops atrox reagent.  

Code of Federal Regulations, 2014 CFR

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

2014-04-01

145

21 CFR 864.8100 - Bothrops atrox reagent.  

Code of Federal Regulations, 2012 CFR

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

2012-04-01

146

21 CFR 864.8100 - Bothrops atrox reagent.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

147

21 CFR 864.8100 - Bothrops atrox reagent.  

Code of Federal Regulations, 2011 CFR

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

2011-04-01

148

21 CFR 864.8100 - Bothrops atrox reagent.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

149

Shifting Attention  

ERIC Educational Resources Information Center

This article examines the shifts in attention and focus as one teacher introduces and explains an image that represents the processes involved in a numeric problem that his students have been working on. This paper takes a micro-analytic approach to examine how the focus of attention shifts through what the teacher and students do and say in the…

Ingram, Jenni

2014-01-01

150

Degradable conjugates from oxanorbornadiene reagents.  

PubMed

Oxanorbornadienedicarboxylate (OND) reagents were explored for purposes of binding and releasing drugs from serum albumins as representative macromolecular carriers. Being highly reactive Michael acceptors, ONDs form adducts with thiols and amines, which then undergo retro-Diels-Alder fragmentation. A study of more than 30 model adducts revealed a number of modifications that can be used to influence adduct stability. For the most reactive OND linkers, the labeling of the single available bovine serum albumin (BSA) cysteine residue was complete within minutes at a mid-micromolar concentration of reactants. While a selectivity of greater than 1000-fold for thiol over amine was observed with model amino acids, the labeling of protein amines with ONDs is fast enough to be practical, as demonstrated by the reaction with thiol-depleted BSA. The OND-amine adducts were found to be up to 15 times more stable than OND-thiol adducts, and to be sensitive to acid by virtue of a stereochemically dependent acceleration of cycloreversion. The release rate of fluorescent cargo from serum albumins was tuned by selecting the coupling partners: the available half-lives ranged from 40 min to 7 days at 37 °C. Such versatility of release profiles from protein carriers, controlled by the nature of the OND linkage, is a useful addition to the drug delivery toolbox. PMID:22455380

Kislukhin, Alexander A; Higginson, Cody J; Hong, Vu P; Finn, M G

2012-04-11

151

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

E-print Network

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

Saber, Aabed (Aabed Saud)

2013-01-01

152

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

SciTech Connect

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

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

1994-06-01

153

Microwave assisted reactions using polyvinylpyrrolidone supported reagents;.  

E-print Network

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

Sebastian, Saju M

2014-01-01

154

Design, synthesis, and evaluation of a lanthanide chelating protein probe: CLaNP-5 yields predictable paramagnetic effects independent of environment.  

PubMed

Immobilized lanthanide ions offer the opportunity to refine structures of proteins and the complexes they form by using restraints obtained from paramagnetic NMR experiments. We report the design, synthesis, and spectroscopic evaluation of the lanthanide chelator, Caged Lanthanide NMR Probe 5 (CLaNP-5) readily attachable to a protein surface via two cysteine residues. The probe causes tunable pseudocontact shifts, alignment, paramagnetic relaxation enhancement, and luminescence, by chelating it to the appropriate lanthanide ion. The observation of single shifts and the finding that the magnetic susceptibility tensors obtained from shifts and alignment analyses are highly similar strongly indicate that the probe is rigid with respect to the protein backbone. By placing the probe at various positions on a model protein it is demonstrated that the size and orientation of the magnetic susceptibility tensor of the probe are independent of the local protein environment. Consequently, the effects of the probe are readily predictable using a protein structure only. These findings designate CLaNP-5 as a protein probe to deliver unambiguous high quality structural restraints in studies on protein-protein and protein-ligand interactions. PMID:18826316

Keizers, Peter H J; Saragliadis, Athanasios; Hiruma, Yoshitaka; Overhand, Mark; Ubbink, Marcellus

2008-11-01

155

Stick shift  

E-print Network

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

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

2004-01-01

156

The Actinide-Lanthanide Separation Process  

SciTech Connect

The Actinide-Lanthanide SEParation (ALSEP) process is described. The process uses an extractant phase consisting of either N,N,N',N'-tetraoctyldiglycolamide (TODGA) or N,N,N',N'-tetra(2 ethylhexyl)diglycolamide (T2EHDGA) combined with 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]). The neutral TODGA or T2EHDGA serves to co-extract the trivalent actinide and lanthanide ions from nitric acid media. Switching the aqueous phase chemistry to a citrate buffered diethylenetriaminepentaacetic acid (DTPA) solution at pH 2.5 to 4 results in selective transfer of the actinides to the aqueous phase, thus resulting in separation of these two groups of elements.

Lumetta, Gregg J.; Gelis, Artem V.; Carter, Jennifer C.; Niver, Cynthia M.; Smoot, Margaret R.

2014-02-21

157

Calmagite as a spectrophotometric reagent for aluminium.  

PubMed

Calmagite is proposed as a sensitive spectrophotometric reagent for aluminium, (570mmu) = 42000. After aqueous phase reaction at pH 8.6, the metal-reagent complex is extracted into chloroform by formation of an ion-association complex with a quaternary ammonium salt. The method is free from interference by common anions, and cationic interferences may be eliminated by the use of cyanide and EDTA as masking agents. PMID:18960299

Woodward, C; Freiser, H

1968-03-01

158

Lanthanide single molecule magnets: progress and perspective.  

PubMed

The last few years have seen a huge renaissance in the study of single molecule magnets (SMMs) thanks to the extensive applications of lanthanide ions with large inherent anisotropy in molecular magnetism. Particularly, the recent theoretical developments and the experimental expansion into the organometallic avenue have led to an eye-catching boost in this field. Here we highlight the recent progress in this fascinating and challenging field, with emphasis on several combined experimental and theoretical studies. PMID:25641200

Zhang, Peng; Zhang, Li; Tang, Jinkui

2015-02-17

159

Lanthanide energy levels in YPO 4  

Microsoft Academic Search

Thermoluminescence (TL) emission spectra and TL glow curves of powder samples of YPO4:Ce3+, Ln3+(Ln3+=Nd3+,Sm3+,Dy3+,Ho3+,Er3+,Tm3+) were measured in order to investigate the nature of the trapping centres and to locate the lanthanide energy levels relative to the valence and conduction bands of the YPO4 host. Trap depths were determined by three different TL techniques (simple formula, various heating rate method and

Adrie J. J. Bos; Pieter Dorenbos; Aurélie Bessière; Bruno Viana

2008-01-01

160

Actinide and lanthanide separation process (ALSEP)  

DOEpatents

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

Guelis, Artem V.

2013-01-15

161

Improved method for extracting lanthanides and actinides from acid solutions  

DOEpatents

A process for the recovery of actinide and lanthanide values from aqueous acidic solutions uses a new series of neutral bi-functional extractants, the alkyl(phenyl)-N,N-dialkylcarbamoylmethylphosphine oxides. 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.P.; Kalina, D.G.; Kaplan, L.; Mason, G.W.

1983-07-26

162

Phthalamide lanthanide complexes for use as luminescent markers  

DOEpatents

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

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

2003-01-01

163

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

164

Salicylamide-lanthanide complexes for use as luminescent markers  

DOEpatents

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

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

2002-01-01

165

Fluid Shifts  

NASA Technical Reports Server (NTRS)

INTRODUCTION: Mechanisms responsible for the ocular structural and functional changes that characterize the visual impairment and intracranial pressure (ICP) syndrome (VIIP) are unclear, but hypothesized to be secondary to the cephalad fluid shift experienced in spaceflight. This study will relate the fluid distribution and compartmentalization associated with long-duration spaceflight with VIIP symptoms. We also seek to determine whether the magnitude of fluid shifts during spaceflight, as well as the VIIP-related effects of those shifts, can be predicted preflight with acute hemodynamic manipulations, and also if lower body negative pressure (LBNP) can reverse the VIIP effects. METHODS: Physiologic variables will be examined pre-, in- and post-flight in 10 International Space Station crewmembers including: fluid compartmentalization (D2O and NaBr dilution); interstitial tissue thickness (ultrasound); vascular dimensions and dynamics (ultrasound and MRI (including cerebrospinal fluid pulsatility)); ocular measures (optical coherence tomography, intraocular pressure, ultrasound); and ICP measures (tympanic membrane displacement, otoacoustic emissions). Pre- and post-flight measures will be assessed while upright, supine and during 15 deg head-down tilt (HDT). In-flight measures will occur early and late during 6 or 12 month missions. LBNP will be evaluated as a countermeasure during HDT and during spaceflight. RESULTS: The first two crewmembers are in the preflight testing phase. Preliminary results characterize the acute fluid shifts experienced from upright, to supine and HDT postures (increased stroke volume, jugular dimensions and measures of ICP) which are reversed with 25 millimeters Hg LBNP. DISCUSSION: Initial results indicate that acute cephalad fluid shifts may be related to VIIP symptoms, but also may be reversible by LBNP. The effect of a chronic fluid shift has yet to be evaluated. Learning Objectives: Current spaceflight VIIP research is described, including novel hardware and countermeasures.

Stenger, M. B.; Hargens, A.; Dulchavsky, S.; Ebert, D.; Lee, S.; Laurie, S.; Garcia, K.; Sargsyan, A.; Martin, D.; Lui, J.; Macias, B.; Arbeille, P.; Danielson, R.; Chang, D.; Gunga, H.; Johnston, S.; Westby, C.; Ribeiro, L.; Ploutz-Snyder, R.; Smith, S.

2015-01-01

166

Electron transfer processes in double lanthanide activated YPO 4  

NASA Astrophysics Data System (ADS)

This work reviews electron transfer processes in double lanthanide doped YPO 4 studied using a diversity of optical techniques. The aim is to identify those transfer processes and to relate them with the location of lanthanide electron donor and lanthanide electron acceptor states within the bandgap of YPO 4. Electron transfer from the valence band to a trivalent lanthanide impurity or to the conduction band was studied by traditional single photon excitation on single lanthanide doped YPO 4. This work reports on YPO 4 doped with the electron donor Ce 3+ and co-doped with an electron acceptor Pr 3+, Er 3+, Nd 3+, Ho 3+, Dy 3+, Tm 3+, or Sm 3+ studied by means of thermoluminescence and optical stimulated luminescence techniques. The same samples were studied by pump and probe two photon spectroscopy utilizing synchrotron photons to transfer electrons from Ce 3+ to Ln 3+ defects and 445 nm laser diode to probe the concentration of created Ln 2+.

Dorenbos, P.; Bos, A. J. J.; Poolton, N. R. J.

2011-05-01

167

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...

168

Total synthesis of natural products using hypervalent iodine reagents  

PubMed Central

We present a review of natural product syntheses accomplished in our laboratory during the last 5 years. Each synthetic route features a phenol dearomatization promoted by an environmentally benign hypervalent iodine reagent. The dearomatizations demonstrate the “aromatic ring umpolung” concept, and involve stereoselective remodeling of the inert unsaturations of a phenol into a highly functionalized key intermediate that may contain a quaternary carbon center and a prochiral dienone system. Several new oxidative strategies were employed, including transpositions (1,3-alkyl shift and Prins-pinacol), a polycyclization, an ipso rearrangement, and direct nucleophilic additions at the phenol para position. Several alkaloids, heterocyclic compounds, and a polycyclic core have been achieved, including sceletenone (a serotonin reuptake inhibitor), acetylaspidoalbidine (an antitumor agent), fortucine (antiviral and antitumor), erysotramidine (curare-like effect), platensimycin (an antibiotic), and the main core of a kaurane diterpene (immunosuppressive agent and stimulator of apoptosis). These concise and in some cases enantioselective syntheses effectively demonstrate the importance of hypervalent iodine reagents in the total synthesis of bioactive natural products. PMID:25601909

Maertens, Gaëtan; L'Homme, Chloé; Canesi, Sylvain

2014-01-01

169

Unnatural Isotopic Composition of Lithium Reagents  

USGS Publications Warehouse

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

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

1997-01-01

170

Controlled release of reagents in capillary-driven microfluidics using reagent integrators.  

PubMed

The integration and release of reagents in microfluidics as used for point-of-care testing is essential for an easy and accurate operation of these promising diagnostic devices. Here, we present microfluidic functional structures, which we call reagent integrators (RIs), for integrating and releasing small amounts of dried reagents (ng quantities and less) into microlitres of sample in a capillary-driven microfluidic chip. Typically, a RI is less than 1 mm(2) in area and has an inlet splitting into a central reagent channel, in which reagents can be loaded using an inkjet spotter, and two diluter channels. During filling of the microfluidic chip, spotted reagents reconstitute and exit the RI with a dilution factor that relates to the relative hydraulic resistance of the channels forming the RI. We exemplify the working principle of RIs by (i) distributing ?100 pg of horseradish peroxidase (HRP) in different volume fractions of a 1 ?L solution containing a fluorogenic substrate for HRP and (ii) performing an immunoassay for C-reactive protein (CRP) using 450 pg of fluorescently labeled detection antibodies (dAbs) that reconstitute in ?5 to 30% of a 1 ?L sample of human serum. RIs preserve the conceptual simplicity of lateral flow assays while providing a great degree of control over the integration and release of reagents in a stream of sample. We believe RIs to be broadly applicable to microfluidic devices as used for biological assays. PMID:21674120

Hitzbleck, Martina; Gervais, Luc; Delamarche, Emmanuel

2011-08-21

171

Relationship between lanthanide contents in aquatic turtles and environmental exposures.  

PubMed

Trace elements released in the environment during agricultural practices can be incorporated and accumulated in biological fluids and tissues of living organisms. The assessment of these exposures were carried out investigating lanthanide distributions in blood and exoskeleton samples collected from Emys trinacris turtle specimens coming from sites with anthropogenic discharge in western and south Sicily, along migration paths of many bird species from Africa to Europe. The data show a significant (Rxy=0.72; Rxy>0.67; ?=0.025) linear relationship between the size of turtle specimens and the lanthanide contents in blood lower than 0.4 ?g L(-1) whereas this relationship disappears in blood with higher lanthanide contents. Comparative evaluations of normalised concentrations show that lanthanides fractionate between blood and exoskeleton inducing antithetical lanthanide patterns therein. These features are more evident in specimens with high lanthanide contents in blood, suggesting that lanthanide accumulations in the exoskeleton can represent the physiological response of E. trinacris to environmental and the further confirmation of relationship occurring between the environmental and the biological fluids. PMID:23411091

Censi, P; Randazzo, L A; D'Angelo, S; Saiano, F; Zuddas, P; Mazzola, S; Cuttitta, A

2013-05-01

172

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

173

Fluid Shifts  

NASA Technical Reports Server (NTRS)

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

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

2014-01-01

174

DEGRADATION OF MTBE INTERMEDIATES USING FENTON'S REAGENT  

EPA Science Inventory

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

175

USE OF FENTON'S REAGENT AS A DISINFECTANT  

EPA Science Inventory

Combined sewage samples obtained from a wastewater treatment facility were disinfected by the Fenton's Reagent of several different compositions. The pre-settled samples contained both suspended solids (SS) and dissolved organic carbon (DOC) at concentrations of 28 and 290 mg/L,...

176

Oxidation of chlorobenzene with Fenton's reagent  

Microsoft Academic Search

The degradation of chlorobenzene and its oxidation products by hydroxyl radicals generated with Fenton's reagent was studied. In the absence of oxygen, chlorophenols, dichlorobiphenyls (DCBs), and phenolic polymers were the predominant initial products. In the presence of oxygen, DCB yields decreased markedly and chlorobenzoquinone was also formed. Chlorophenol isomers were further oxidized by OH's to form chlorinated and nonchlorinated diols.

David L. Sedlak; Anders W. Andren

1991-01-01

177

AQUEOUS RELAXATION REAGENTS IN NITROGEN-15 NMR  

EPA Science Inventory

Electron-nuclear relaxation times T(1)supe's for 15N and 13C in natural abundance are measured for a series of amines in aqueous solution using Gd(III) complexes of a series of polyaminocarboxylate ligands as paramagnetic relaxation reagents (PARRs). The PARRs are classified by t...

178

Whole worm glycerol assay Reagents needed  

E-print Network

Whole worm glycerol assay Reagents needed: 1. Dry Ice 2. Mortar and pestles 3. 1N Perchloric acid-biopharm) Protocol 1. Wash worms off plates w/ M9 (make sure osmolarity matches that of plate) 2. Wash twice 3. Resuspend worm pellet in 10 ml M9 and allow worms to evacuate bacteria for 15 minutes. 4. While worms

Lamitina, Todd

179

USE OF FENTON'S REAGENT AS DISINFECTING AGENT  

EPA Science Inventory

This project was conducted as an EPA in-house research, assisted by the on-site contractor, US Infrastructure, Inc. (USI) located in Edison, NJ. The Fenton's reagent (e.g., H2O2, ferrous iron Fe(aq)+2) is an alternative method of chemical oxidation. Hydroxyl radicals (OH ), gen...

180

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

181

Remarks on preparation of indandione detection reagents  

NASA Technical Reports Server (NTRS)

A modified Claisen condensation with sliced sodium at a higher temperature was recommended for the production of ungranulated charcoal. A new ninhydrin production method by oxidation of benzaldiketohydrinden using available reagents was tried and was unsuccessful. Triketohydrinden was obtained by boiling ninhydrin in acetic acid anhydrides.

Stepan, J.; Kral, V.

1985-01-01

182

Determination of Cellular Cholesterol Content Reagents Needed  

E-print Network

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

Pike, Linda J.

183

Ion exchange in hydroxyapatite with lanthanides.  

PubMed

Naturally occurring hydroxyapatite, Ca5(PO4)3(OH) (HAP), is the main inorganic component of bone matrix, with synthetic analogues finding applications in bioceramics and catalysis. An interesting and valuable property of both natural and synthetic HAP is the ability to undergo cationic and anionic substitution. The lanthanides are well-suited for substitution for the Ca(2+) sites within HAP, because of their similarities in ionic radii, donor atom requirements, and coordination geometries. We have used isothermal titration calorimetry (ITC) to investigate the thermodynamics of ion exchange in HAP with a representative series of lanthanide ions, La(3+), Sm(3+), Gd(3+), Ho(3+), Yb(3+) and Lu(3+), reporting the association constant (Ka), ion-exchange thermodynamic parameters (?H, ?S, ?G), and binding stoichiometry (n). We also probe the nature of the La(3+):HAP interaction by solid-state nuclear magnetic resonance ((31)P NMR), X-ray diffraction (XRD), and inductively coupled plasma-optical emission spectroscopy (ICP-OES), in support of the ITC results. PMID:25594577

Cawthray, Jacqueline F; Creagh, A Louise; Haynes, Charles A; Orvig, Chris

2015-02-16

184

21 CFR 866.3700 - Staphylococcus aureus serological reagents.  

Code of Federal Regulations, 2010 CFR

21 Food and Drugs 8 2010-04-01...2010-04-01 false Staphylococcus aureus serological reagents...Section 866.3700 Food and Drugs FOOD AND DRUG ADMINISTRATION...Reagents § 866.3700 Staphylococcus aureus serological...

2010-04-01

185

21 CFR 866.3280 - Francisella tularensis serological reagents.  

Code of Federal Regulations, 2012 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3280 Francisella tularensis serological reagents....

2012-04-01

186

21 CFR 866.3870 - Trypanosoma 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 § 866.3870 Trypanosoma spp. serological reagents. (a)...

2013-04-01

187

21 CFR 866.3175 - Cytomegalovirus serological reagents.  

Code of Federal Regulations, 2011 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3175 Cytomegalovirus serological reagents. (a)...

2011-04-01

188

21 CFR 866.3870 - Trypanosoma spp. serological reagents.  

Code of Federal Regulations, 2014 CFR

... Food and Drugs 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)...

2014-04-01

189

21 CFR 866.3020 - Adenovirus 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 § 866.3020 Adenovirus serological reagents. (a)...

2013-04-01

190

21 CFR 866.3140 - Corynebacterium spp. serological reagents.  

Code of Federal Regulations, 2011 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3140 Corynebacterium spp. serological reagents. (a)...

2011-04-01

191

21 CFR 866.3125 - Citrobacter spp. serological reagents.  

Code of Federal Regulations, 2012 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3125 Citrobacter spp. serological reagents. (a)...

2012-04-01

192

21 CFR 866.3630 - Serratia 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 § 866.3630 Serratia spp. serological reagents. (a)...

2013-04-01

193

21 CFR 866.3020 - Adenovirus serological reagents.  

Code of Federal Regulations, 2011 CFR

... Food and Drugs 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)...

2011-04-01

194

21 CFR 866.3300 - Haemophilus spp. serological reagents.  

Code of Federal Regulations, 2014 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3300 Haemophilus spp. serological reagents. (a)...

2014-04-01

195

21 CFR 866.3550 - Salmonella spp. serological reagents.  

Code of Federal Regulations, 2014 CFR

... Food and Drugs 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)...

2014-04-01

196

21 CFR 866.3175 - Cytomegalovirus serological reagents.  

Code of Federal Regulations, 2014 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3175 Cytomegalovirus serological reagents. (a)...

2014-04-01

197

21 CFR 866.3020 - Adenovirus serological reagents.  

Code of Federal Regulations, 2014 CFR

... Food and Drugs 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)...

2014-04-01

198

21 CFR 866.3300 - Haemophilus spp. serological reagents.  

Code of Federal Regulations, 2011 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3300 Haemophilus spp. serological reagents. (a)...

2011-04-01

199

21 CFR 866.3250 - Erysipelothrix rhusiopathiae serological reagents.  

Code of Federal Regulations, 2011 CFR

... Food and Drugs 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....

2011-04-01

200

21 CFR 866.3165 - Cryptococcus neoformans 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 § 866.3165 Cryptococcus neoformans serological reagents....

2013-04-01

201

21 CFR 866.3550 - Salmonella 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 § 866.3550 Salmonella spp. serological reagents. (a)...

2013-04-01

202

21 CFR 866.3200 - Echinococcus spp. serological reagents.  

Code of Federal Regulations, 2012 CFR

... Food and Drugs 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)...

2012-04-01

203

21 CFR 866.3200 - Echinococcus 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 § 866.3200 Echinococcus spp. serological reagents. (a)...

2013-04-01

204

21 CFR 866.3020 - Adenovirus serological reagents.  

Code of Federal Regulations, 2012 CFR

... Food and Drugs 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)...

2012-04-01

205

21 CFR 866.3270 - Flavobacterium spp. serological reagents.  

Code of Federal Regulations, 2014 CFR

... Food and Drugs 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)...

2014-04-01

206

21 CFR 866.3700 - Staphylococcus aureus 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 § 866.3700 Staphylococcus aureus serological reagents. (a)...

2013-04-01

207

21 CFR 866.3660 - Shigella spp. serological reagents.  

Code of Federal Regulations, 2011 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)...

2011-04-01

208

21 CFR 866.3340 - Klebsiella spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3340 Klebsiella spp. serological reagents. (a)...

2010-04-01

209

21 CFR 866.3280 - Francisella tularensis 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 § 866.3280 Francisella tularensis serological reagents....

2013-04-01

210

21 CFR 866.3850 - Trichinella spiralis serological reagents.  

Code of Federal Regulations, 2010 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3850 Trichinella spiralis serological reagents. (a)...

2010-04-01

211

21 CFR 866.3340 - Klebsiella spp. serological reagents.  

Code of Federal Regulations, 2012 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3340 Klebsiella spp. serological reagents. (a)...

2012-04-01

212

21 CFR 866.3120 - Chlamydia serological reagents.  

Code of Federal Regulations, 2010 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)...

2010-04-01

213

21 CFR 866.3085 - Brucella spp. serological reagents.  

Code of Federal Regulations, 2011 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3085 Brucella spp. serological reagents. (a)...

2011-04-01

214

21 CFR 866.3085 - Brucella spp. serological reagents.  

Code of Federal Regulations, 2012 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3085 Brucella spp. serological reagents. (a)...

2012-04-01

215

21 CFR 866.3200 - Echinococcus spp. serological reagents.  

Code of Federal Regulations, 2014 CFR

... Food and Drugs 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)...

2014-04-01

216

21 CFR 866.3350 - Leptospira spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3350 Leptospira spp. serological reagents. (a)...

2010-04-01

217

21 CFR 866.3120 - Chlamydia serological reagents.  

Code of Federal Regulations, 2012 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)...

2012-04-01

218

21 CFR 866.3500 - Rickettsia 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 § 866.3500 Rickettsia serological reagents. (a)...

2013-04-01

219

21 CFR 866.3125 - Citrobacter spp. serological reagents.  

Code of Federal Regulations, 2014 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3125 Citrobacter spp. serological reagents. (a)...

2014-04-01

220

21 CFR 866.3250 - Erysipelothrix rhusiopathiae 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 § 866.3250 Erysipelothrix rhusiopathiae serological reagents....

2013-04-01

221

21 CFR 866.3470 - Reovirus serological reagents.  

Code of Federal Regulations, 2011 CFR

... Food and Drugs 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)...

2011-04-01

222

21 CFR 866.3600 - Schistosoma 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 § 866.3600 Schistosoma spp. serological reagents. (a)...

2013-04-01

223

21 CFR 866.3175 - Cytomegalovirus serological reagents.  

Code of Federal Regulations, 2012 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3175 Cytomegalovirus serological reagents. (a)...

2012-04-01

224

21 CFR 866.3600 - Schistosoma spp. serological reagents.  

Code of Federal Regulations, 2014 CFR

... Food and Drugs 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)...

2014-04-01

225

21 CFR 866.3660 - Shigella spp. serological reagents.  

Code of Federal Regulations, 2012 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)...

2012-04-01

226

21 CFR 866.3470 - Reovirus serological reagents.  

Code of Federal Regulations, 2012 CFR

... Food and Drugs 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)...

2012-04-01

227

21 CFR 866.3165 - Cryptococcus neoformans serological reagents.  

Code of Federal Regulations, 2014 CFR

... Food and Drugs 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....

2014-04-01

228

21 CFR 866.3125 - Citrobacter spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3125 Citrobacter spp. serological reagents. (a)...

2010-04-01

229

21 CFR 866.3660 - Shigella spp. serological reagents.  

Code of Federal Regulations, 2010 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)...

2010-04-01

230

21 CFR 866.3470 - Reovirus 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 § 866.3470 Reovirus serological reagents. (a)...

2013-04-01

231

21 CFR 866.3140 - Corynebacterium spp. serological reagents.  

Code of Federal Regulations, 2010 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3140 Corynebacterium spp. serological reagents. (a)...

2010-04-01

232

21 CFR 866.3110 - Campylobacter fetus serological reagents.  

Code of Federal Regulations, 2014 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3110 Campylobacter fetus serological reagents. (a)...

2014-04-01

233

21 CFR 866.3120 - Chlamydia serological reagents.  

Code of Federal Regulations, 2014 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)...

2014-04-01

234

21 CFR 864.8950 - Russell viper venom reagent.  

Code of Federal Regulations, 2011 CFR

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

2011-04-01

235

21 CFR 864.8950 - Russell viper venom reagent.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

236

21 CFR 864.8950 - Russell viper venom reagent.  

Code of Federal Regulations, 2012 CFR

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

2012-04-01

237

21 CFR 864.8950 - Russell viper venom reagent.  

Code of Federal Regulations, 2014 CFR

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

2014-04-01

238

21 CFR 864.8950 - Russell viper venom reagent.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

239

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...

240

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

ERIC Educational Resources Information Center

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

Orchin, Milton

1989-01-01

241

Luminescent lanthanide (Eu3+, Tb3+) hybrids with 4-vinylbenzeneboronic acid functionalized Si-O bridges and beta-diketones.  

PubMed

4-Vinylphenylboronic acid ligand (VPBA) is functionalized with two crosslinking reagents (3-(triethoxysilyl)-propylisocyanate [TEPIC] and 3-(trimethoxysilyl) propyl methacrylate [TMPMA]) to achieve the two special molecular bridge VPBA-TEPIC and VPBA-TMPMA. Meanwhile, beta-diketone ligands (2-thenoyltrifluoroacetone [TTA], acetyl acetone [ACAC]) as the second ligands play the role of the main energy donor, which absorb abundant energy in ultraviolet-visible extent and then transfer the energy to the corresponding lanthanide ions (Eu(3+), Tb(3+)) to sensitize their emission of them. Eight binary and ternary Eu(3+), Tb(3+) hybrids with VPBA-TEPIC (VPBA-TMPMA) and TTA (ACAC) have been constructed, whose photoluminescence properties are studied in depth and suggest that the ternary hybrids show the favorable characteristic luminescent properties (longer lifetime and higher quantum efficiency). PMID:21466557

Yan, Bing; Guo, Min; Qiao, Xiao-Fei

2011-01-01

242

Lighting up cells with lanthanide self-assembled helicates  

PubMed Central

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

Bünzli, Jean-Claude G.

2013-01-01

243

Development of an Intelligent Polymerized Crystalline Colloidal Array Colorimetric Reagent  

E-print Network

Development of an Intelligent Polymerized Crystalline Colloidal Array Colorimetric Reagent Chad E, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 We have developed a novel colorimetric reagent angle relative to the incident light. We have developed a new colorimetric reagent for the determination

Asher, Sanford A.

244

21 CFR 660.30 - Reagent Red Blood Cells.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

245

21 CFR 660.30 - Reagent Red Blood Cells.  

Code of Federal Regulations, 2011 CFR

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

2011-04-01

246

21 CFR 660.30 - Reagent Red Blood Cells.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 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....

2014-04-01

247

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

248

21 CFR 660.30 - Reagent Red Blood Cells.  

Code of Federal Regulations, 2012 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

249

Microscopy on anesthetized worms Reagents needed  

E-print Network

Microscopy on anesthetized worms Reagents needed · Vacuum grease syringe · M9 + 5 mM Na Azide (3µl of M9/NaAzide in a watchglass slide 2. Pick 5-10 worms off an NGM plate and into the azide into the square. 6. Pick anesthetized worms onto the slide and gently overlay them with a 22 x 22 mm coverslip. 7

Lamitina, Todd

250

New fluorinating reagents from acesulfam sweeteners  

Microsoft Academic Search

Oxathiazinone dioxides, a group of well known sweetening agents, have been used for the synthesis of a new type of heterocyclic N-F reagents. Benz-1,2,3-oxathiazin-4(3F)-one 2,2-dioxide (1c), for example, is a stable crystalline compound, which can be used for the electrophilic fluorination of a variety of organic compounds under very mild conditions.

Ivan Cabrera; Wolfgang K. Appel

1995-01-01

251

{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

252

17O NMR study of diamagnetic and paramagnetic lanthanide(III)-DOTA complexes in aqueous solution.  

PubMed

The complexes between the polyaminocarboxylate DOTA ligand and the whole series of stable lanthanide(III) metal ions, except Gd(3+), were studied in aqueous solution by (17)O NMR. For all of the paramagnetic systems, the (17)O NMR signals of both the nonchelating (O1) and chelating (O2) oxygen atoms could be detected, and for some of them, the signals of both the SAP and TSAP (TSAP') conformational isomers were also observed. Line width data analysis reveals that signal broadening is not dominated by paramagnetic relaxation enhancement, as it was believed to be. The data indicate that quadrupole relaxation and, for some complexes, chemical exchange between the SAP and TSAP isomers are the major contributions to the (17)O NMR line width at 25 °C. Besides, the Fermi contact and pseudocontact contributions to the observed lanthanide-induced shifts could be extracted. The (17)O hyperfine coupling constants determined for O2 in the SAP and TSAP isomers are similar to each other and to the values reported for several Gd(III) complexes comprising fast-exchanging ligands. Interestingly, the results suggest that (17)O NMR should prove to be useful for the study of highly paramagnetic Gd(III) complexes of nonlabile ligands. PMID:25090036

Fusaro, Luca; Luhmer, Michel

2014-08-18

253

21 CFR 866.3235 - Epstein-Barr virus serological reagents.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 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...

2011-04-01

254

21 CFR 866.3235 - Epstein-Barr virus serological reagents.  

Code of Federal Regulations, 2014 CFR

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

2014-04-01

255

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

256

21 CFR 866.3235 - Epstein-Barr virus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 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...

2010-04-01

257

21 CFR 866.3235 - Epstein-Barr virus serological reagents.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 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...

2012-04-01

258

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

259

Lanthanide(III) Complexes with a Reinforced Cyclam Ligand Show Unprecedented Kinetic Inertness.  

PubMed

Lanthanide(III) complexes of a cross-bridged cyclam derivative containing two picolinate pendant arms are kinetically inert in very harsh conditions such as 2 M HCl, with no dissociation being observed for at least 5 months. Importantly, the [Ln(dota)](-) complexes, which are recognized to be extremely inert, dissociate under these conditions with lifetimes in the range ca. 1 min to 12 h depending upon the Ln(3+) ion. X-ray diffraction studies reveal octadentate binding of the ligand to the metal ion in the [Eu(cb-tedpa)](+) complex, while (1)H and (13)C NMR experiments in D2O point to the presence of a single diastereoisomer in solution with a very rigid structure. The structure of the complexes in the solid state is retained in solution, as demonstrated by the analysis of the Yb(3+)-induced paramagnetic shifts. PMID:25495928

Rodríguez-Rodríguez, Aurora; Esteban-Gómez, David; Tripier, Raphaël; Tircsó, Gyula; Garda, Zoltán; Tóth, Imre; de Blas, Andrés; Rodríguez-Blas, Teresa; Platas-Iglesias, Carlos

2014-12-31

260

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

261

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

262

Lanthanide-based time-resolved luminescence immunoassays.  

PubMed

The sensitive and specific detection of analytes such as proteins in biological samples is critical for a variety of applications, for example disease diagnosis. In immunoassays a signal in response to the concentration of analyte present is generated by use of antibodies labeled with radioisotopes, luminophores, or enzymes. All immunoassays suffer to some extent from the problem of the background signal observed in the absence of analyte, which limits the sensitivity and dynamic range that can be achieved. This is especially the case for homogeneous immunoassays and surface measurements on tissue sections and membranes, which typically have a high background because of sample autofluorescence. One way of minimizing background in immunoassays involves the use of lanthanide chelate labels. Luminescent lanthanide complexes have exceedingly long-lived luminescence in comparison with conventional fluorophores, enabling the short-lived background interferences to be removed via time-gated acquisition and delivering greater assay sensitivity and a broader dynamic range. This review highlights the potential of using lanthanide luminescence to design sensitive and specific immunoassays. Techniques for labeling biomolecules with lanthanide chelate tags are discussed, with aspects of chelate design. Microtitre plate-based heterogeneous and homogeneous assays are reviewed and compared in terms of sensitivity, dynamic range, and convenience. The great potential of surface-based time-resolved imaging techniques for biomolecules on gels, membranes, and tissue sections using lanthanide tracers in proteomics applications is also emphasized. PMID:21556751

Hagan, A K; Zuchner, T

2011-07-01

263

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...

264

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 PMID:1060096

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

1975-01-01

265

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

266

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

2009-03-14

267

Enhanced TCDD degradation by Fenton's reagent preoxidation.  

PubMed

The dioxin isomer 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been called the most toxic compound known to man. Because of its poor bioavailability and low biodegradibility, bioremediation technology cannot effectively degrade TCDD when used alone. In this study, chemical pretreatment (partial oxidation) in combination with biodegradation technique was developed to efficiently remediate TCDD-contaminated soils. An oxidizing reagent [Fenton's Reagent (FR)] was applied in a slurry reactor to transform TCDD with a concentration of 96 microg per kg of soil to compounds more amenable to biodegradation. Up to 99% TCDD was transformed after the chemical pretreatment process. The slurry reactor was then converted to a bioreactor for the following biodegradation experiment. The detected TCDD oxidation byproducts including chlorophenols (CPs) and chlorobenzenes (CBs) were transformed in this bioreactor under aerobic conditions. Two other biodegradation experiments were performed in parallel to investigate the biodegradabiliy of TCDD under aerobic and anaerobic conditions without chemical pretreatment. Approximately 53% TCDD was transformed under anaerobic conditions possibly due to the reductive dechlorination process using organic materials contained in the activated sludge as the primary substrates. No TCDD degradation was observed under aerobic conditions. Results show that FR can oxidize TCDD to less-chlorinated and less-toxic byproducts, promoting their bioavailability to microbial communities. The bench-scale results indicate that the two-stage (partial oxidation followed by biodegradation) system has the potential to be developed to remediate TCDD-contaminated soils on-site. PMID:10794914

Kao, C M; Wu, M J

2000-06-30

268

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

269

Mixed lanthanide oxide nanoparticles as dual imaging agent in biomedicine  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

270

New quinolone-based thiol-reactive lanthanide luminescent probes  

PubMed Central

Luminescent lanthanide ion complexes are distinguished by unique light emitting properties that enable both highly sensitive detection of lanthanide labels attached to biomolecules and contrast imaging of various micro objects (cells, nanoparticles, etc.). Previously, we synthesized amine-reactive cs124-based luminescent lanthanide chelates with improved brightness and metal retention. Here we report the synthesis of new thiol-reactive derivatives of the same compounds including bromoacetamido-, and maleimido- forms of cs124 and cs124CF3 fluorophores. Maleimido-compounds displayed exceptional reactivity instantaneously coupling to thiols at physiological conditions at micromolar probes concentrations. Surprisingly, they displayed strong quenching by adjacent maleimido-group, which was completely eliminated after reaction with thiols, thereby enabling their simple detection by monitoring the light emission of the reaction mixture. This reaction can be used for hyper-sensitive determination of biologically important sulphydryl compounds (e.g. glutathione, co-enzyme A, etc.) in time-resolved mode. PMID:23833545

Wirpsza, Laura; Krasnoperov, Lev; Mustaev, Arkady

2013-01-01

271

Ultrasensitive DNAzyme beacon for lanthanides and metal speciation.  

PubMed

Metal-ion detection and speciation analysis is crucial for environmental monitoring. Despite the importance of lanthanides, few sensors are available for their detection. DNAzymes have been previously used to detect divalent metals, while no analytical work was carried out for trivalent and tetravalent ions. Herein, in vitro selection was performed using a Ce(4+) salt as the target metal, and a new DNAzyme (named Ce13) with a bulged hairpin structure was isolated and characterized. Interestingly, Ce13 has almost no activity with Ce(4+) but is highly active with all trivalent lanthanides and Y(3+), serving as a general probe for rare earth metals (omitting Sc). A DNAzyme beacon was engineered detecting down to 1.7 nM Ce(3+) (240 parts per trillion), and other lanthanides showed similar sensitivity. The feasibility of metal speciation analysis was demonstrated by measuring the reduction of Ce(4+) to Ce(3+). PMID:24383540

Huang, Po-Jung Jimmy; Lin, Jenny; Cao, Jing; Vazin, Mahsa; Liu, Juewen

2014-02-01

272

Mixed lanthanide oxide nanoparticles as dual imaging agent in biomedicine  

PubMed Central

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

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

2013-01-01

273

Analytical separations of lanthanides and actinides by capillary electrophoresis.  

PubMed

The separation of lanthanide and actinide elements belongs to one of the most challenging tasks of the separation science, due to a great similarity in their physical and chemical properties. The electrophoretic separation can be accomplished in the presence of suitable complex-forming agents, from which alpha-hydroxyisobutyric acid (HIBA) has been used most often. In the most effective capillary electrophoretic mode--capillary zone electrophoresis (CZE)--a complete separation of lanthanide ions can be accomplished within a few minutes. Various electrophoretic methods can be relatively easily adopted for the determinations of individual lanthanide elements in certain kinds of technical materials, concentrates, precursors, etc., where the high speed and low costs of analysis characteristics of capillary electrophoresis (CE) may be advantageously exploited. Electrophoretic techniques may also be employed for speciation studies, especially for examinations of the behavior of actinides in the environment. PMID:12858369

Janos, Pavel

2003-06-01

274

Sterilization of a biological safety cabinet by vaporized KMT reagent.  

PubMed

To investigate effective methods to sterilize a biological safety cabinet contaminated with Bacillus spores, a sterilization study was performed using the vaporized KMT reagent. Five kinds of test carriers inoculated with Bacillus subtilis spores, which had been prepared in-house, were used as indicators. The KMT reagent was placed in the middle of the work-area (1.2 m-wide, Class II type A cabinet). Approximately 300 ml of vaporized KMT reagent could bring about complete sterilization of this cabinet by 24 h of exposure without severe corrosion. Vaporized KMT reagent could be used for the safe and easy sterilization of cabinets contaminated with Bacillus spores. PMID:17629248

Kida, Nori; Mochizuki, Yasushi; Taguchi, Fumiaki

2007-06-01

275

Applications of DFT to Lanthanides and Precious Metal Complexes  

NASA Astrophysics Data System (ADS)

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

Hurley, Margaret; Balboa, Alex; Jenkins, Amanda

2013-03-01

276

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

277

Plasma mass filtering for separation of actinides from lanthanides  

NASA Astrophysics Data System (ADS)

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

Gueroult, R.; Fisch, N. J.

2014-06-01

278

Method for providing oxygen ion vacancies in lanthanide oxides  

DOEpatents

A method for desulfurization of fuel gases resulting from the incomplete combustion of sulfur containing hydrocarbons whereby the gases are treated with lanthanide oxides containing large numbers of oxygen-ion vacancies providing ionic porosity which enhances the ability of the lanthanide oxides to react more rapidly and completely with the sulfur in the fuel gases whereby the sulfur in such gases is reduced to low levels suitable for fuels for firing into boilers of power plants generating electricity with steam turbine driven generators, gas turbines, fuel cells and precursors for liquid fuels such as methanol and the like.

Kay, D. Alan R. (4305 Lakeshore Rd., Burlington, CA); Wilson, William G. (820 Harden Dr., Pittsburgh, PA 15229)

1989-12-05

279

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

NASA Technical Reports Server (NTRS)

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

Sharma, Prasanta; Cheung, Herbert C.

1989-01-01

280

Oxidation of chlorobenzene with Fenton's reagent  

SciTech Connect

The degradation of chlorobenzene and its oxidation products by hydroxyl radicals generated with Fenton's reagent was studied. In the absence of oxygen, chlorophenols, dichlorobiphenyls (DCBs), and phenolic polymers were the predominant initial products. In the presence of oxygen, DCB yields decreased markedly and chlorobenzoquinone was also formed. Chlorophenol isomers were further oxidized by OH's to form chlorinated and nonchlorinated diols. DCBs and the phenolic polymers were also oxidized. The highest yield of product formed per mole of H{sub 2}O{sub 2} consumed was observed in the pH range of 2-3. The pH dependence and product distributions suggest that complexes of aromatic intermediate compounds with iron and oxygen may play a role in regulating reaction pathways. At pH 3.0, approximately 5 mol of H{sub 2}O{sub 2}/mol of chlorobenzene were required to remove all of the aromatic intermediate compounds from solution.

Sedlak, D.L.; Andren, A.W. (Univ. of Wisconsin, Madison (United States))

1991-04-01

281

Phenylethynyl endcapping reagents and reactive diluents  

NASA Technical Reports Server (NTRS)

A phenylethynyl composition which can be used to endcap nucleophilic species is employed in the production of phenylethynyl terminated reactive oligomers exclusively. These phenylethynyl terminated reactive oligomers display unique thermal characteristics, as exemplified by the model compound, 4-phenoxy 4'-phenylethynylbenzophenone, which is relatively stable at 200 C, but reacts at 350 C. In addition, a reactive diluent was prepared which decreases the melt viscosity of the phenylethynyl terminated oligomers and subsequently reacts therewith to increase density of the resulting thermoset. The novelty of this invention resides in the phenylethynyl composition used to terminate a nucleophilic reagent, resulting in the exclusive production of phenylethynyl terminated reactive oligomers which display unique thermal characteristics. A reactive diluent was also employed to decrease the melt viscosity of a phenylethynyl terminated reactive oligomer and to subsequently react therewith to increase the crosslink density of the resulting thermoset. These materials have features which make them attractive candidates for use as composite matrices and adhesives.

Jensen, Brian J. (inventor); Bryant, Robert G. (inventor); Hergenrother, Paul M. (inventor)

1994-01-01

282

RNA SHAPE chemistry with aromatic acylating reagents.  

PubMed

As chemical methods for RNA secondary structure determination, SHAPE chemistry (selective 2'-hydroxyl acylation analyzed by primer extension) has been developed to specifically target flexible nucleotides (often unpaired nucleotides) independently to their purine or pyrimidine nature. In order to improve the specificity of acylating reagents towards unpaired nucleotides, we have explored the reactivity of symmetric anhydrides, acyl fluorides, active esters like succinimidyl ester and cyanomethyl esters for 2'-O-acylation reaction. Among the tested compounds, only the acyl fluoride 4 showed a low reactivity (compared to NMIA). However, this study is the first to show that nucleophilic catalysts like DMAP greatly improved the selective 2'-hydroxyl acylation by symmetric anhydrides, acyl fluorides and succinimidyl ester, with the 2-fluorobenzoic anhydride 5 being the most reactive. PMID:25557357

Nodin, Laura; Noël, Olivier; Chaminade, Françoise; Maskri, Ouerdia; Barbier, Vincent; David, Olivier; Fossé, Philippe; Xie, Juan

2015-02-01

283

4-Methoxyphenylphosphonic acid: reactivity of Lawesson's reagent.  

PubMed

The title compound, C(7)H(9)O(4)P, obtained as a by-product of the reaction between Lawesson's reagent, (I), and CH(3)I, can be recognized as the final product of the S/O interchange reaction at the P atom of (I). Hydrogen bonds of type P-O-H.O=P link molecules into helical chains and form ten-membered hydrogen-bonded rings with the graph-set notation R(3)(2)(10). Weaker intermolecular contacts between P-O and a phenyl H atom link the chains into a three-dimensional lattice. The parent benzenephosphonic acid [Weakley (1976). Acta Cryst. B32, 2889-2890] does not adopt an analogous structure, but its arsenic analogue [Shimada (1960). Bull. Chem. Soc. Jpn, 33, 301-304] does and can be regarded as isostructural. We rationalize these three structures in terms of their significant intermolecular interactions. PMID:11983984

Aragoni, M Carla; Arca, Massimiliano; Blake, Alexander J; Lippolis, Vito; Schröder, Martin; Wilson, Claire

2002-05-01

284

THE U.S. VETERINARY IMMUNE REAGENTS NETWORK  

Technology Transfer Automated Retrieval System (TEKTRAN)

As stated at USDA http://www.csrees.usda.gov, “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 a...

285

Structure-kinetic relationship study of organozinc reagents.  

PubMed

Phenylzinc reagents prepared from various zinc halides show distinct kinetic features in the palladium-catalyzed Negishi-type oxidative coupling reaction, in which the phenylzinc reagent prepared from ZnI2 gives the highest rate. In situ infrared and X-ray absorption spectroscopy studies show that the higher reaction rate was observed for longer Zn-C bond distances. PMID:24964262

Zhang, Guanghui; Li, Jing; Deng, Yi; Miller, Jeffrey T; Kropf, A Jeremy; Bunel, Emilio E; Lei, Aiwen

2014-08-14

286

Slow Release Of Reagent Chemicals From Gel Matrices  

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

287

Decontamination of MDA Reagents for Single Cell Whole Genome Amplification  

Microsoft Academic Search

Single cell genomics is a powerful and increasingly popular tool for studying the genetic make-up of uncultured microbes. A key challenge for successful single cell sequencing and analysis is the removal of exogenous DNA from whole genome amplification reagents. We found that UV irradiation of the multiple displacement amplification (MDA) reagents, including the Phi29 polymerase and random hexamer primers, effectively

Tanja Woyke; Alexander Sczyrba; Janey Lee; Christian Rinke; Damon Tighe; Scott Clingenpeel; Rex Malmstrom; Ramunas Stepanauskas; Jan-Fang Cheng; Olivier Lespinet

2011-01-01

288

EFFECT OF FENTON'S REAGENT ON SUBSURFACE MICROBIOLOGY AND BIODEGRADATION CAPACITY  

EPA Science Inventory

Microcosm studies were conducted to determine the effect of Fenton's reagent on subsurface microbiology and biodegradation capacity in a DNAPL (PCE/TCE) contaminated aquifer previously treated with the reagent. Groundwater pH declined from 5 to 2.4 immediately after the treatmen...

289

Fluorescent Labeling Reagents Optimized for Capillary Electrophoretic Separations  

E-print Network

M range, and did not alter the migration behavior of proteins in the sieving matrix. A third fluorescent labeling reagent was developed as a solid phase reagent (SPR) where the fluorophore was immobilized on a solid surface through a cleavable anchor...

Estrada, Roy Tonacao, III

2012-02-14

290

IN-PLACE REGENERATION OF GAC USING FENTON'S REAGENTS  

EPA Science Inventory

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

291

PROTHROMBIN (PT) REAGENT CHANGE AT UNIVERSITY OF CONNECTICUT HEALTH CENTER  

E-print Network

PROTHROMBIN (PT) REAGENT CHANGE AT UNIVERSITY OF CONNECTICUT HEALTH CENTER WHAT: We will change to a new, highly sensitive reagent for PT/INR testing. WHEN: The new test will be in use Thursday, February 27, 2014, at 12am. IMPACT: The sensitivity of the PT to oral anticoagulant therapy with warfarin has

Oliver, Douglas L.

292

Polyaminocarboxylic acids as potential candidates for trivalent actinide/lanthanide separations  

NASA Astrophysics Data System (ADS)

Nuclear energy, which has historically been considered an alternative energy solution in the United States, is regaining support as an efficient means of energy production. The viability of nuclear energy for the future, however, will remain suspect until issues involving the waste created are fully addressed in the next generation of advanced nuclear fuel cycles. The TALSPEAK process, developed at Oak Ridge National Laboratory, is a classic solvent extraction technique that employs a series of analytical separations in an effort to remove radioactive contaminants from spent nuclear fuel (SNF) and recover uranium in high purity. This separation utilizes a polyaminocarboxylic acid and a phosphorous extractant to separate trivalent actinides (An(III)s) from trivalent lanthanides (Ln(III)s). Conversely, issues with these reagents have hampered TALSPEAK's implementation as an industrial scale solution. The process requires a high concentration of lactic acid to facilitate phase separations, and the An(III)/Ln(III) separation factor is too low to achieve the purity required for artificial transmutation. Artificial transmutation involves steady neutron irradiation, which is impossible in the presence of Ln(III)s because of large neutron capture cross-sections. It is therefore critical to develop superior solvent extractants that effectively separate An(III)s from Ln(III)s. The present study focuses on the design, synthesis, characterization and analysis of advanced polyaminocarboxylic acids and their metal complexes in an effort to identify potential TALSPEAK-type extractants with superior separation properties. A facile, higher yield synthesis of these ligands and their complexation of trivalent metal ions (Co(III), Al(III), Ga(III), and In(III)), and selected lanthanides are reported. The polyaminocarboxylic acids and their trivalent metal complexes were characterized by elemental analysis, mass spectrometry, IR spectroscopy and NMR spectroscopy. Quantum mechanical calculations were performed to obtain the relative stabilities of the three possible geometric isomers for pseudo-octahedral polyaminocarboxylate metal complexes in solution. The calculations were supported by X-ray crystallographic data obtained for different Co(III) and Ga(III) polyaminocarboxylate complexes. Advanced 2D NOESY and classic 1D NMR spectroscopy were used to differentiate experimentally between cis- (C1 symmetry) and both trans- (C2 symmetry) isomers. IR spectroscopy was used to investigate the nature of carboxylate binding for metal complexes isolated in the solid state.

Kissel, Daniel S.

293

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

294

Plasmonic enhancement of lanthanides luminescence using metallic nanoparticles  

NASA Astrophysics Data System (ADS)

This work summarizes how plasmonic phenomena can enhance the fluorescence of lanthanides (Ln3+) coupled to metallic nanoparticles (MNP). Lanthanide-ions emission lines, based on 4f-4f transitions, are weak due to Laporte selection rules for optical transitions. This effect results in low absorption cross sections for excitation and long lifetimes for emission processes. We propose to use metallic nanoparticles in order to determine how plasmonic nanoparticles can enhance absorption and emission of two emblematic lanthanides ions used for bio-labeling and energy conversion, i.e., Eu3+ and Er3+. This work quantifies the average enhancement factor (AEF) is expected for different geometries of nanoparticle structures and compares it to previous studies. Then, we theoretically and numerically investigate metal-enhanced fluorescence of plasmonic core-shell nanoparticles doped with lanthanides ions. The shape and size of the particles are engineered to maximize the average enhancement factor of the overall doped shell. We show with theoretical considerations and numerical studies that the highest enhancement (11 in the visible and 7 in the near-infrared) is achieved by tuning either the dipolar or the quadrupolar particle resonance to the rare-earth ion's excitation wavelength. Additionally, the calculated AEFs are compared to experimental data reported in the literature, obtained under similar conditions (plasmon-mediated enhancement) or when a metal-Ln3+ energy-transfer mechanism is involved.

Berthelot, A.; Derom, S.; Abdellaoui, N.; Benamara, O.; Pillonnet, A.; Pereira, A.; Colas des Francs, G.; Moine, B.; Jurdyc, A.-M.

2014-03-01

295

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

296

Enhancement of anion binding in lanthanide optical sensors.  

PubMed

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

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

2013-11-19

297

Enhancement of Anion Binding in Lanthanide Optical Sensors  

PubMed Central

In the design of molecular sensors, researchers exploit binding interactions that are usually defined in terms of topology and charge complementarity. The formation of complementary arrays of highly cooperative, noncovalent bonding networks facilitates protein-ligand binding, leading to motifs such as the ‘lock-and-key.’ Synthetic molecular sensors often employ metal complexes as key design elements as a way to construct a binding site with the desired shape and charge to achieve target selectivity. In transition metal complexes, coordination number, structure and ligand dynamics are governed primarily by a combination of inner-sphere covalent and outer-sphere noncovalent interactions. These interactions provide a rich variable space that researchers can use to tune structure, stability and dynamics. In contrast, lanthanide(III)-ligand complex formation and ligand-exchange dynamics are dominated by reversible electrostatic and steric interactions, because the unfilled f shell is shielded by the larger, filled d shell. Luminescent lanthanides such as terbium, europium, dysprosium and samarium display many photophysical properties that make them excellent candidates for molecular sensor applications. Complexes of lanthanide ions act as receptors that exhibit a detectable change in metal-based luminescence upon binding of an anion. In our work on sensors for detection of dipicolinate, the unique biomarker of bacterial spores, we discovered that the incorporation of an ancillary ligand (AL) can enhance binding constants of target anions to lanthanide ions by as much as two orders of magnitude. In this Account, we show that selected ALs in lanthanide/anion systems greatly improve sensor performance for medical, planetary science and biodefense applications. We suggest that the observed anion binding enhancement could result from an AL-induced increase in positive charge at the lanthanide ion binding site. This effect depends on lanthanide polarizability, which can be established from the ionization energy of Ln3+ ? Ln4+. These results account for the order Tb3+ > Dy3+ > Eu3+ ? Sm3+. As with many lanthanide properties, ranging from hydration enthalpy to vaporization energy, this AL-induced enhancement shows a large discrepancy between Tb3+ and Eu3+ despite their similarity in size, a phenomenon known as the ‘gadolinium break.’ This discrepancy, based on the unusual stabilities of the Eu2+ and Tb4+ oxidation states, results from the half-shell effect, as both of these ions have half-filled 4f-shells. The high polarizability of Tb3+ explains the extraordinarily large increase in the binding affinity of anions for terbium compared to other lanthanides. We recommend that researchers consider this AL-induced enhancement when designing lanthanide-macrocycle optical sensors. Ancillary ligands also can reduce the impact of interfering species such as phosphate) commonly found in environmental and physiological samples. PMID:24032446

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

2013-01-01

298

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

299

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

2006-06-16

300

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

301

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

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 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...

2014-04-01

302

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

Code of Federal Regulations, 2010 CFR

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

2010-04-01

303

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

Code of Federal Regulations, 2011 CFR

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

2011-04-01

304

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

Code of Federal Regulations, 2012 CFR

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

2012-04-01

305

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

Code of Federal Regulations, 2010 CFR

...part 101-44. Drugs, biologicals, and reagents which...When surplus drugs, biologicals, and reagents are...designated donee from the Food and Drug Administration...compliance with the Federal Food, Drug, and Cosmetic... Surplus drugs, biologicals, and reagents...

2010-07-01

306

Bacterial production of isobutanol without expensive reagents.  

PubMed

Isobutanol is attracting attention as a potential biofuel because it has higher energy density and lower hygroscopicity than ethanol. To date, several effective methods for microbial production of isobutanol have been developed, but they require expensive reagents to maintain expression plasmids and induce expression, which is not suitable for practical production. Here, we describe a simple and efficient method for isobutanol production in Escherichia coli. It is noteworthy that no expression plasmids or inducers were used during the production. Instead, heterologous genes necessary for isobutanol production were all knocked into the genome, and the expression of those genes was induced by xylose, which is present in most biomass feedstocks. The constructed strain (mlcXT7-LAFC-AAKCD) contains Bacillus subtilis alsS, E. coli ilvCD, Lactococcus lactis adhA, and L. lactis kivd genes in its genome and efficiently produced isobutanol from glucose and xylose in flask batch cultures. Under conditions in which the temperature and pH of the medium and the aeration in the culture were all optimized, the final isobutanol concentration reached 8.4 g L(-1) after 48 h. Isobutanol was also produced using hydrolysate from Japanese cedar as the carbon source without supplemented glucose, xylose, or yeast extract. Under those conditions, isobutanol (3.7 g L(-1)) was produced in 96 h. Taken together, these results indicate that the developed strain is potentially useful for industrial isobutanol production. PMID:25359477

Akita, Hironaga; Nakashima, Nobutaka; Hoshino, Tamotsu

2014-10-31

307

Reactivity of chemiluminescence reagents toward oxidants  

SciTech Connect

Hydroperoxyl radical (HO{sub 2}) and its conjugate base, superoxide radical (O{sub 2}{sup -}) are important chemical intermediates. O{sub 2}{sup -} is ubiquitous in aerobic cells and has been implicated in arthritis, cancer, and aging, among other biological processes. HO{sub 2} plays a central role in atmospheric photochemistry. Because of their short lifetime, there are few reliable analytical methods for the detection of HO{sub 2}/O{sub 2}{sup -}. In a number of recent publications, the chemiluminescence reagent CLA has been exploited as a specific marker for these species. Using UV/visible spectroscopy, we have investigated the stability of CLA and several of its analogs in the presence of oxidants, including O{sub 2}, H{sub 2}O{sub 2}, OH and HO{sub 2}/O{sub 2}{sup -}. The spectral changes observed suggest that the reaction with HO{sub 2}/O{sub 2}{sup -} is rather nonspecific.

Khevelev, M.; Weinstein-Loyd, J.B. [State Univ. of New York, Old Westbury, NY (United States)

1996-10-01

308

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

309

Spectroscopic study on the photophysical properties of novel lanthanide complexes with long chain mono-L phthalate (L = hexadecyl, octadecyl and eicosyl)  

NASA Astrophysics Data System (ADS)

Ortho-phthalic anhydride was modified with long chain alcohol (1-hexadecanol, 1-octadecanol and 1-eicosanol) to their corresponding mono-L phthalate (L = hexadecyl, octadecyl and eicosyl), i.e. monohexadecyl phthalate (16-Phth), monooctadecyl phthalate (18-Phth), and monoeicosyl phthalate (20-Phth), respectively. Nine novel lanthanide (Eu 3+, Tb 3+ and Dy 3+) complexes with these three mono-L phthalate ligands were synthesized and characterized by elemental analysis and IR spectra. The photophysical properties of these complexes were studied in detail with various spectroscopes such as ultraviolet-visible absorption spectra, low temperature phosphorescence spectra and fluorescent spectra. The ultraviolet-visible absorption spectra show some band shifts with the different chain-length of phthalate monoester and homologous lanthanide complexes. From the low temperature phosphorescent emission, the triplet state energies for these three ligands were determined to be around 22,650 cm -1 (16-Phth), 23,095 cm -1 (18-Phth) and 22,400 cm -1 (20-Phth), respectively, suggesting they are suitable for the sensitization of the luminescence of Eu 3+, Tb 3+ and Dy 3+. The fluorescence excitation and emission spectra for these lanthanides complexes of the three ligands take agreement with the above predict from energy match.

Yan, Bing; Xu, Bing

2005-11-01

310

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

SciTech Connect

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

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

1999-04-01

311

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

SciTech Connect

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

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

2013-07-01

312

Lanthanide-containing polycations for monitoring polyplex dynamics via lanthanide resonance energy transfer.  

PubMed

Theranostic nanomaterials have emerged in the past decade that combine therapeutic delivery and diagnostic imaging into one package. Such materials offer the opportunity to aid diagnosis, track therapeutic biodistribution, and monitor drug release. We have developed a series of nucleic acid delivery polymers containing oligoethylene amines that are able to be protonated at physiological pH (for binding/compacting pDNA) and a lanthanide-chelating domain, which imparts diagnostic functionality. Diamine monomers (containing between 3 and 6 Boc-protected ethyleneamines) were prepared via a multistep procedure involving the selective protection and deprotection of primary and secondary amines. The polymer structures were then synthesized by step-growth polymerization of the oligoethylene diamines with a bisanhydride of diethylenetriamine pentaacetic acid (DTPA-BA), yielding degrees of polymerization between 18 and 24. Chelation of the polymers with gadolinium and terbium was performed to offer MRI contrast agent and luminescence properties, respectively. All of the polymer chelates were found to house approximately one water coordination site, as calculated by the Horrock's equation and possess longitudinal relaxivities (r1, on a per Gd basis) at least twice that of Magnevist, a clinical contrast agent. All the structures formed polyplexes with pDNA with highly positive zeta potentials and hydrodynamic diameters around 50-80 nm. Lanthanide resonance energy transfer (LRET) was used to monitor polyplex association and dissociation. Polyplexes were formed using the donor-acceptor pair comprising of terbium-chelated polymer with five ethyleneamines within the repeat unit (6c-Tb) and tetramethyl rhodamine (TMR)-labeled pDNA. Association/dissociation in the presence of heparin and NaCl was monitored. The effect of amine number along the polymer backbone on transfection efficiency and cytotoxicity was also investigated. None of the polymers revealed cytotoxic effects with cultured cells; however, the polymer with six ethyleneamines clearly offered the highest transfection efficiency. This preliminary study offers insight into the development of materials with the ability to monitor polyplex unpackaging over time within the cellular environment. PMID:24611467

Kelkar, Sneha S; Xue, Lian; Turner, S Richard; Reineke, Theresa M

2014-05-12

313

Reagent Selection Methodology for a Novel Explosives Detection Platform (Image of Marvin Warner, Ph.D.)  

E-print Network

Transcript Reagent Selection Methodology for a Novel Explosives Detection Platform 1 TRANSCRIPT of the explosive. #12;Transcript Reagent Selection Methodology for a Novel Explosives Detection Platform 2 ("Find

314

Standard Materials for Microbeam Analysis of Lanthanides and Actinides  

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

315

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

316

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

SciTech Connect

Through the marriage of mesoporous ceramics with self-assembled monolayer chemistry, the genesis of a powerful new class of environmental sorbent materials has been realized. By coating the mesoporous ceramic backbone with a monolayer terminated with a lanthanide-specific ligand, it is possible to couple high lanthanide binding affinity with the high loading capacity (resulting from the extremely high surface area of the support). This lanthanide-specific ligand field is created by pairing a ''hard'' anionic Lewis base with a suitable synergistic ligand, in a favorable chelating geometry. Details of the synthesis, characterization, lanthanide binding studies, binding kinetics, competition experiments and sorbent regeneration studies are summarized

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

2004-11-01

317

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

SciTech Connect

Through the marriage of mesoporous ceramics with self-assembled monolayer chemistry, the genesis of a powerful new class of environmental sorbent materials has been realized. By coating the mesoporous ceramic backbone with a monolayer terminated with a lanthanide-specific ligand, it is possible to couple high lanthanide binding affinity with the high loading capacity (resulting from the extremely high surface area of the support). This lanthanide-specific ligand field is created by pairing a “hard” anionic Lewis base with a suitable synergistic ligand, in a favorable chelating geometry. Details of the synthesis, characterization, lanthanide binding studies, binding kinetics, competition experiments and sorbent regeneration studies are summarized.

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

2004-11-01

318

Polymeric Microspheres as Protein Transduction Reagents*  

PubMed Central

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

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

2014-01-01

319

21 CFR 866.3700 - Staphylococcus aureus serological reagents.  

Code of Federal Regulations, 2014 CFR

...reagents are devices that consist of antigens and antisera used in serological tests to identify enterotoxin (toxin affecting the intestine) producing staphylococci from cultured isolates. The identification aids in the diagnosis of disease caused by this...

2014-04-01

320

21 CFR 866.3630 - Serratia spp. serological reagents.  

Code of Federal Regulations, 2014 CFR

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

2014-04-01

321

Novel microporous lanthanide silicates with tobermorite-like structure.  

PubMed

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

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

2003-11-26

322

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

NASA Astrophysics Data System (ADS)

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

Otobe, Haruyoshi

2013-11-01

323

A TRUEX-based separation of americium from the lanthanides  

SciTech Connect

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

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

2011-03-01

324

Lanthanides caged by the organic chelates; structural properties  

NASA Astrophysics Data System (ADS)

The structure, in particular symmetry, geometry and morphology of organic chelates coordinated with the lanthanide ions are analyzed in the present review. This is the first part of a complete presentation of a theoretical description of the properties of systems, which are widely used in technology, but most of all, in molecular biology and medicine. The discussion is focused on the symmetry and geometry of the cages, since these features play a dominant role in the spectroscopic activity of the lanthanides caged by organic chelates. At the same time, the spectroscopic properties require more formal presentation in the language of Racah algebra, and deserve a separate analysis. In addition to the parent systems of DOTA, DOTP, EDTMP and CDTMP presented here, their modifications by various antennas are analyzed. The conclusions that have a strong impact upon the theory of the energy transfer and the sensitized luminescence of these systems are based on the results of numerical density functional theory calculations.

Smentek, Lidia

2011-04-01

325

Lanthanides caged by the organic chelates; structural properties.  

PubMed

The structure, in particular symmetry, geometry and morphology of organic chelates coordinated with the lanthanide ions are analyzed in the present review. This is the first part of a complete presentation of a theoretical description of the properties of systems, which are widely used in technology, but most of all, in molecular biology and medicine. The discussion is focused on the symmetry and geometry of the cages, since these features play a dominant role in the spectroscopic activity of the lanthanides caged by organic chelates. At the same time, the spectroscopic properties require more formal presentation in the language of Racah algebra, and deserve a separate analysis. In addition to the parent systems of DOTA, DOTP, EDTMP and CDTMP presented here, their modifications by various antennas are analyzed. The conclusions that have a strong impact upon the theory of the energy transfer and the sensitized luminescence of these systems are based on the results of numerical density functional theory calculations. PMID:21422507

Smentek, Lidia

2011-04-13

326

A self-assembling lanthanide molecular nanoparticle for optical imaging.  

PubMed

Chromophores that incorporate f-block elements have considerable potential for use in bioimaging applications because of their advantageous photophysical properties compared to organic dye, which are currently widely used. We are developing new classes of lanthanide-based self-assembling molecular nanoparticles as reporters for imaging and as multi-functional nanoprobes or nanosensors for use with biological samples. One class of these materials, which we call lanthanide "nano-drums", are homogeneous 4d-4f clusters approximately 25 to 30 Å in diameter. These are capable of emitting from the visible to near-infrared wavelengths. Here, we present the synthesis, crystal structure, photophysical properties and comparative cytotoxicity data for a 32 metal Eu-Cd nano-drum [Eu8Cd24L12(OAc)48] (). We also explored the imaging capabilities of this nano-drum using epifluorescence, TIRF, and two-photon microscopy platforms. PMID:25512085

Brown, Katherine A; Yang, Xiaoping; Schipper, Desmond; Hall, Justin W; DePue, Lauren J; Gnanam, Annie J; Arambula, Jonathan F; Jones, Jessica N; Swaminathan, Jagannath; Dieye, Yakhya; Vadivelu, Jamuna; Chandler, Don J; Marcotte, Edward M; Sessler, Jonathan L; Ehrlich, Lauren I R; Jones, Richard A

2015-01-28

327

Synthesis and characterization of a series of porous lanthanide tricarboxylates  

Microsoft Academic Search

The synthesis of a series of 11 porous lanthanides-based MOFs formulated Ln(C27H15O6)(H2O)·x(solv) (denoted MIL-103) (Ln=La to Ho, Y), presenting large one-dimensional channels and a high surface area after dehydration, is reported. X-ray diffraction (XRD) reveals that these solids crystallize in the chiral space group R32 (no. 155) with a slight contraction of the cell parameters according to the ionic radii

Thomas Devic; Virgile Wagner; Nathalie Guillou; Alexandre Vimont; Mohamed Haouas; Michele Pascolini; Christian Serre; Jérome Marrot; Marco Daturi; Francis Taulelle; Gérard Férey

2011-01-01

328

Complexes of Alkyl Esters of Ethylidenediphosphonic Acids with Lanthanide Nitrates  

Microsoft Academic Search

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

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

2008-01-01

329

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

330

Magnetic circular dichroism of porphyrin lanthanide M3+ complexes.  

PubMed

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

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

2014-10-01

331

Alginate-lanthanide microspheres for MRI-guided embolotherapy.  

PubMed

In cancer therapy, a promising treatment option to accomplish a high tumor-to-normal-tissue ratio is endovascular intervention with microsized particles, such as embolotherapy. In this study, alginate microspheres (ams) were prepared with the JetCutter technique, which is based on cutting a sodium alginate solution jet stream into small droplets of uniform size which are then cross-linked with different lanthanides or iron-III, resulting in microspheres of a predefined size which can be visualized by magnetic resonance imaging (MRI). The microspheres were investigated for their size and morphology (light microscopy and scanning electron microscopy analysis), cation content and MRI properties. The lanthanide-ams formulations, with a uniform size of 250 ?m and a cation content between 0.72-0.94%, showed promising results for MR imaging. This was further demonstrated for Ho(3+)-cross-linked alginate microspheres (Ho(3+)-ams), the most potent microsphere formulation with respect to MR visualization, allowing single sphere detection and detailed microsphere distribution examination. Intravascular infusion of Ho(3+)-ams by catherization of ex vivo rabbit and porcine liver tissue and assessment of the procedure with MRI clearly showed accumulation and subsequently embolization of the targeted vessels, allowing accurate monitoring of the microsphere biodistribution throughout the tissue. Therefore, the different alginate-lanthanide microsphere formulations developed in this study show great potential for utilization as image-guided embolotherapy agents. PMID:22947326

Oerlemans, Chris; Seevinck, Peter R; van de Maat, Gerrit H; Boulkhrif, Hassan; Bakker, Chris J G; Hennink, Wim E; Nijsen, J Frank W

2013-01-01

332

Magnetic Relaxation Mechanisms in Lanthanide Single Molecule Magnets  

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

333

Semiempirical quantum chemistry model for the lanthanides: RM1 (Recife Model 1) parameters for dysprosium, holmium and erbium.  

PubMed

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

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

2014-01-01

334

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

PubMed Central

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

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

2014-01-01

335

Dynamic sodium chemical shift imaging for the study of aqueous humor flow.  

PubMed

Ocular images were obtained using sodium chemical shift imaging (CSI) and 1,4,7,10-tetraazacyclododecane-N,N'N",N"'-tetramethylenephospho nate thulium (III) [Tm(DOTP)5-], a paramagnetic chemical shift reagent. After injecting the shift reagent into the anterior chamber of rabbits, serial imaging was done, monitoring the change in chemical shift with time. Sodium CSI produced images of the eye in three dimensions, quantitatively depicting the spatial and temporal changes in the concentration of a paramagnetic tracer substance. The Tm(DOTP)5- is eliminated from the anterior chamber by first-order kinetics with a half-life of 49 min. These data suggest that this substance is eliminated from the anterior chamber at the same rate as aqueous humor is replaced. Sodium CSI shows promise as a valuable technique for monitoring fluid dynamics in the living eye. PMID:2071335

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

1991-07-01

336

Oxygen-induced magnetic surface states on the ,,0001... surfaces of heavy lanthanide metals C. Schuler-Langeheine,1  

E-print Network

Oxygen-induced magnetic surface states on the ,,0001... surfaces of heavy lanthanide metals C. Schu adsorption on the close-packed surfaces of trivalent heavy lanthanide metals leads to the formation of well, resembling the surface states of the clean metal surfaces. For the magnetic lanthanides, these states exhibit

Grigoriev, Alexei

337

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

338

Salen-based metal-organic frameworks of nickel and the lanthanides.  

PubMed

A well defined salen-nickel complex was introduced as "metalloligand" in lanthanide-based MOFs. By using this strategy unique structures, in which the salen-nickel unit acts as flexible strut, were obtained. The shape of the network is strongly influenced by the ion radius of the lanthanide element. PMID:21210028

Roesky, Peter W; Bhunia, Asamanjoy; Lan, Yanhua; Powell, Annie K; Kureti, Sven

2011-02-21

339

Calix[4]arenes as selective extracting agents. An NMR dynamic and conformational investigation of the lanthanide(III) and thorium(IV) complexes  

SciTech Connect

The lanthanide and Th{sup 4+} complexes with calix[4]arene ligands substituted either on the narrow or at the wide rim by four coordinating groups behave totally differently as shown by an NMR investigation of the dia- and paramagnetic complexes. Solutions of complexes were prepared by reacting anhydrous metal perchlorate salts with the ligands in dry acetonitrile (CAUTION). Relaxation time T{sub 1} titrations of acetonitrile solutions of Gd{sup 3+} by calixarenes indicate that ligands substituted on the narrow rim form stable 1:1 complexes whether they feature four amide groups (1) or four phosphine oxide functions. In contrast, a ligand substituted by four (carbamoylmethyl)-diphenylphosphine oxide moieties on the wide rim (3) and its derivatives form polymeric species even at a 1:1 ligand/metal concentration ratio. Nuclear magnetic relaxation dispersion (NMRD) curves (relaxation rates 1/T{sub 1} vs magnetic field strength) of Gd{sup 3+}, Gd{sup 3+}{center_dot}1 and Gd{sup 3+}{center_dot}3 perchlorates in acetonitrile are analyzed by an extended version of the Solomon-Bloembergen-Morgan equations. A comparison of the calculated rotational correlation times {tau}{sub r} shows that ligand 3 forms oligomeric Gd{sup 3+} species. The chelates of ligand 1 are axially symmetric (C{sub 4} symmetry), and the paramagnetic shifts induced by the Yb{sup 3+} ion are accounted for quantitatively. The addition of water or of nitrate ions does not modify the geometry of the complex. The metal chelates of 3 and its derivatives adopt a C{sub 2} symmetry, and the paramagnetic shifts are interpreted on a semiquantitative basis only. Water and NO{sub 3}{sup {minus}} ions completely labilize the complexes of the heavy lanthanides. The very high selectivity of ligand 3 through the lanthanide series stems from a complex interplay of factors.

Lambert, B.; Jacques, V.; Shivanyuk, A.; Matthews, S.E.; Tunayar, A.; Baaden, M.; Wipff, G.; Boehmer, V.; Desreux, J.F.

2000-05-15

340

Detection of lanthanides and actinides in solutions based on laser-induced luminescence and chemiluminescence  

NASA Astrophysics Data System (ADS)

This work is devoted to applications of the time-resolved laser- induced luminescence spectroscopy and time-resolved laser-induced chemiluminescence spectroscopy for detection of lanthanides and actinides. The limit of detection (LOD) of some lanthanides and actinides in solutions by the time-resolved laser luminescence spectroscopy is up to 10-13 mole/liter. Unfortunately, Pu, Np, and some U compounds do not produce luminescence in solutions, but when excited by laser radiation, they can induce chemiluminescence. The characteristics of chemiluminescence induced by excited lanthanide and actinide complexes in solutions are considered. A key problem of chemiluminescence application for lanthanide and actinide detection in solutions is the increase of the detection selectivity. This problem can be solved by using the multistep schemes of chemiluminescence excitation. It is shown that the time-resolved luminescence laser spectroscopy and chemiluminescence laser spectroscopy can be successfully used for detection of lanthanides and actinides in solutions.

Izosimov, I. N.; Firsin, N. G.; Gorshkov, N. G.; Nekhoroshkov, S. N.

2014-06-01

341

alpha-Bromo-4-amino-3-nitroacetophenone, a new reagent for protein modification. Modification of the methionine-290 residue of porcine pepsin.  

PubMed Central

A new coloured reagent for protein modification, alpha-bromo-4-amino-3-nitroacetophenone (NH2BrNphAc), was synthesized. The reagent was found to alkylate specifically the methionine-290 residue of porcine pepsin below pH 3 at 37 degrees C, which lead to a 45% decrease of enzyme's activity towards haemoglobin. The effect of this reagent as well as that of other phenacyl bromides on the activity of pepsin appeared to be a result of steric hindrance caused by the attachment of bulky reagent residue to the edge of the cleft harbouring the enzyme active site. Only marginal reaction with the co-carboxy group of aspartic acid-315 was found under the above conditions. More pronounced esterification of carboxy groups (up to one residue per enzyme molecule) occurred when the pH was shifted to 5.2. The latter modification had no noticeable effect on enzyme activity, thus disproving a previously held assumption that pepsin inactivation by phenacyl bromide is due to the carboxy-group esterification. alpha-Bromo-4-amino-3-nitroacetophenone forms derivatives with characteristic u.v. spectra when it reacts with methionine, histidine, aspartic and glutamic acid residues, and may be recommended as a reagent for protein modification. PMID:6772159

Tarasova, N I; Lavrenova, G I; Stepanov, V M

1980-01-01

342

Luminescent hybrid lanthanide sulfates and lanthanide sulfonate-carboxylates with 1,10-phenanthroline involving in-situ oxidation of 2-mercaptonbenzoic acid  

NASA Astrophysics Data System (ADS)

A series of lanthanide sulfates and lanthanide sulfonate-carboxylates, [Ln2(phen)2(SO4)3(H2O)2]n (I:Ln=Nd(1a), Sm(1b), Eu(1c), phen=1,10-phenanthroline) and [Ln(phen)(2-SBA)(BZA)]n (II: Ln=Sm(2a), Eu(2b), Dy(2c), 2-SBA=2-sulfobenzoate, BZA=benzoate) have been hydrothermally synthesized from lanthanide oxide, 2-mercaptonbenzoic acid with phen as auxiliary ligand and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, TG analyses and luminescence spectroscopy. Interestingly, SO42- anions in I came from the in situ deep oxidation of thiol groups of 2-mercaptonbenzoic acid while 2-sulfobenzoate and benzoate ligands in II from the middle oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. Compounds I are organic-inorganic hybrid lanthanide sulfates, which have rare one-dimensional column-like structures. Complexes II are binuclear lanthanide sulfonate-carboxylates with 2-sulfobenzoate and benzoate as bridges and 1,10-phenanthroline as terminal. Photoluminescence studies reveal that complexes I and II exhibit strong lanthanide characteristic emission bands in the solid state at room temperature.

Zhong, Jie-Cen; Wan, Fang; Sun, Yan-Qiong; Chen, Yi-Ping

2015-01-01

343

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

2013-02-01

344

Synthesis and application of cleavable photoactivable heterobifunctional reagents.  

PubMed

Three different cleavable photoactivable heterobifunctional reagents have been synthesized and characterized by proton NMR, 13C NMR, mass spectroscopy, infrared spectroscopy, and thin-layer chromatography. They are the N-hydroxysuccinimide ester of 3-[(4-azidophenyl)dithio]-propionic acid, methyl 3-[(4-azidophenyl)dithio]propionimidate, and N-[(4-azidophenyl)thio]phthalimide. Concanavalin A was coupled with one of the reagents, the N-hydroxysuccinimide ester of 3-[(4-azidophenyl)dithio]propionic acid, and radioiodinated. The [125I]lectin derivative and [125I]lectin showed similar specific binding to the receptors on the human erythrocyte membrane. Upon photolysis, subunits of the [125I]lectin derivative were cross-linked to produce dimer, trimer, and tetramer. These cross-linked complexes were readily cleaved by reducing the disulfide bond of the reagent. PMID:7317350

Vanin, E F; Ji, T H

1981-11-24

345

A peptidomimetic siRNA transfection reagent forhighly effectivegene silencing  

SciTech Connect

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

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

2006-05-17

346

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

PubMed Central

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

2013-01-01

347

A lanthanide complex with dual biosensing properties: CEST and BIRDS with EuDOTA-(gly)4?  

PubMed Central

Responsive contrast agents (RCAs) [R1.12] composed of lanthanide III ion (Ln3+) complexes with a variety of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate (DOTA4?) derivatives have shown great potential as molecular imaging agents for magnetic resonance (MR). A variety of LnDOTA-tetraamide complexes have been demonstrated as RCAs for molecular imaging with chemical exchange saturation transfer (CEST). The CEST method detects proton exchange between bulk water and any exchangeable sites on the ligand itself or an inner sphere of bound water that is shifted by a paramagnetic Ln3+ bound in the core of the macrocycle. It has also been shown that molecular imaging is possible when the RCA itself is observed (i.e., not its affect on bulk water) using a method called biosensor imaging of redundant deviation in shifts (BIRDS). The BIRDS method utilizes redundant information stored in the non-exchangeable proton resonances emanating from the paramagnetic RCA for ambient factors like temperature and/or pH. Thus CEST and BIRDS rely on exchangeable and non-exchangeable protons, respectively, for biosensing. We posited that it is feasible to combine these two biosensing features into the same RCA (i.e., dual CEST and BIRDS properties). A complex between europium ion (Eu3+) and DOTA-tetra-glycinate (DOTA-(gly)44?) is used to demonstrate that its CEST characteristics are preserved while BIRDS properties are detected. In vitro temperature sensitivity of EuDOTA-(gly)4? is used to show that qualitative MR contrast with CEST can be calibrated using quantitative MR mapping with BIRDS, thereby enabling quantitative molecular imaging at high spatial resolution. PMID:22020775

Coman, Daniel; Kiefer, Garry E.; Rothman, Douglas L.; Sherry, A. Dean; Hyder, Fahmeed

2011-01-01

348

Effects of diatomic reagent alignment on the A + BC reaction  

NASA Technical Reports Server (NTRS)

A computational study is reported on the A + BC - AB + C bimolecular exchange reaction in which BC is aligned with respect to the approach direction of atom A so that the initial rotational angular momentum vector of BC is either parallel (or equivalently antiparallel) or perpendicular to the initial velocity vector of A. The calculations employ a modification of the extended LEPS potential, which permits straightforward generation of noncollinear minimum energy reaction paths. The calculations clearly demonstrate that diatomic reagent alignment can markedly affect the nature of reaction product early partitioning; they also demonstrate that diatomic reagent alignment affects reactive cross sections.

Pattengill, M. D.; Zare, R. N.; Jaffe, R. L.

1987-01-01

349

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

350

Shifting scintillator neutron detector  

DOEpatents

Provided are sensors and methods for detecting thermal neutrons. Provided is an apparatus having a scintillator for absorbing a neutron, the scintillator having a back side for discharging a scintillation light of a first wavelength in response to the absorbed neutron, an array of wavelength-shifting fibers proximate to the back side of the scintillator for shifting the scintillation light of the first wavelength to light of a second wavelength, the wavelength-shifting fibers being disposed in a two-dimensional pattern and defining a plurality of scattering plane pixels where the wavelength-shifting fibers overlap, a plurality of photomultiplier tubes, in coded optical communication with the wavelength-shifting fibers, for converting the light of the second wavelength to an electronic signal, and a processor for processing the electronic signal to identify one of the plurality of scattering plane pixels as indicative of a position within the scintillator where the neutron was absorbed.

Clonts, Lloyd G; Cooper, Ronald G; Crow, Jr., Morris Lowell; Hannah, Bruce W; Hodges, Jason P; Richards, John D; Riedel, Richard A

2014-03-04

351

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

NASA Astrophysics Data System (ADS)

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

Moore, Brian Freeman

352

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

353

Lithium Reagents DOI: 10.1002/anie.200603038  

E-print Network

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

Collum, David B.

354

Reagent ultrafiltration purification of water contaminated with reactive dyes  

Microsoft Academic Search

Wastewater from the textile industry is characterized by a varying and often unidentified composition. The basic contaminants normally present include surfactants, organic and mineral acids, bleachers and dyes. These substances deteriorate the quality of the water downstream via direct contamination and through the occurrence of secondary processes. The use of reagent treatment methods does not always lead to sufficient purification.

S Petrov; PA Stoichev

2002-01-01

355

Product specification ECL Plus Western blotting reagent pack  

E-print Network

, such as laboratory overalls, safety glasses and gloves. Care should be taken to avoid contact with the skin or eyes. In the case of contact with skin or eyes, wash immediately with water. Description This kit contains reagents.1% is usually sufficient) for 1 hour at room temperature on an orbital shaker. 2) Washing PBS or TBS Tween (0

Kirschner, Marc W.

356

CPTC expand scope of Reagents and Resources Core  

Cancer.gov

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

357

Hypersensitivity pneumonitis in a technician using Pauli's reagent  

Microsoft Academic Search

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

W V Evans; A Seaton

1979-01-01

358

Reagents for Electrophilic Amination: A Quantum Monte CarloStudy  

SciTech Connect

Electroamination is an appealing synthetic strategy toconstruct carbon-nitrogen bonds. We explore the use of the quantum MonteCarlo method and a proposed variant of the electron-pair localizationfunction--the electron-pair localization function density--as a measureof the nucleophilicity of nitrogen lone-pairs as a possible screeningprocedure for electrophilic reagents.

Amador-Bedolla, Carlos; Salomon-Ferrer, Romelia; Lester Jr.,William A.; Vazquez-Martinez, Jose A.; Aspuru-Guzik, Alan

2006-11-01

359

Electronic properties of lanthanide oxides from the GW perspective  

NASA Astrophysics Data System (ADS)

A first-principles understanding of the electronic properties of f-electron systems is currently regarded as a great challenge in condensed-matter physics because of the difficulty in treating both localized and itinerant states on the same footing by the current theoretical approaches, most notably density-functional theory (DFT) in the local-density or generalized gradient approximation (LDA/GGA). Lanthanide sesquioxides (Ln2O3) are typical f-electron systems for which the highly localized f states play an important role in determining their chemical and physical properties. In this paper, we present a systematic investigation of the performance of many-body perturbation theory in the GW approach for the electronic structure of the whole Ln2O3 series. To overcome the major failure of LDA/GGA, the traditional starting point for GW, for f-electron systems, we base our GW calculations on Hubbard U corrected LDA calculations (LDA+U). The influence of the crystal structure, the magnetic ordering, and the existence of metastable states on the electronic band structures are studied at both the LDA+U and the GW level. The evolution of the band structure with increasing number of f electrons is shown to be the origin for the characteristic structure of the band gap across the lanthanide sesquioxide series. A comparison is then made to dynamical mean-field theory (DMFT) combined with LDA or hybrid functionals to elucidate the pros and cons of these different approaches.

Jiang, Hong; Rinke, Patrick; Scheffler, Matthias

2012-09-01

360

Luminescent dinuclear lanthanide complexes of 5-Me-HXTA.  

PubMed

The synthesis and characterization of a series of anionic homobimetallic lanthanide complexes of the septadentate chelate 5-Me-HXTA (N,N-(2 hydroxy-5-methyl-1,3-xylylene)bis(N-(carboxymethyl)glycine) is described (Ln = Nd, Sm, Eu, Tb, Dy, Ho, Er, Yb). Single X-ray crystallography confirms that the complexes exist as discrete dimeric pairs in the solid state. Proton NMR, diffusion-ordered spectroscopy, and luminescence solution studies suggest that the binuclear stoichiometry is retained in aqueous solution over a range of analytically useful concentrations. The phenolic chromophores effectively sensitize the visible and near-infrared lanthanide-centered emission in the terbium, neodymium, and ytterbium derivatives, giving rise to particularly long-lived green and near-infrared emission. The terbium complex displays a high quantum yield of around 50% in aqueous solution with a low detection limit of 1 x 10(-12) M, rendering this compound a potential candidate for time-resolved applications. PMID:17985871

Natrajan, Louise S; Timmins, Phillipa L; Lunn, Matthew; Heath, Sarah L

2007-12-10

361

Energetic lanthanide complexes: coordination chemistry and explosives applications  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

362

Effective Atomic Numbers of Lanthanides with Gamma Radiation for Photon Energy Absorption  

NASA Astrophysics Data System (ADS)

Effective atomic numbers for photon energy absorption, ZPEA,eff have been calculated for photon from 1 keV to 20 MeV for selected oxides of lanthanides, such as Lanthanum oxide, Cerium oxide, Samarium oxide, Europium oxide, Dysprosium oxide, Thulium oxide, Ytterbium oxide. The ZPEA,eff values then compared with ZPI,eff for photon interaction. The ZPEA,eff values have been found to change with energy and composition of selected lanthanides. Oxides of lanthanides are considered as better shielding materials to the exposure of gamma radiation. The values of effective atomic number for photon energy absorption help in the calculation of absorbed dose.

Shantappa, Anil; Hanagodimath, S. M.

363

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

364

Lanthanide impurity level location in GaN, AlN, and ZnO  

NASA Astrophysics Data System (ADS)

A method that has proven succesful in locating the energy levels of divalent and trivalent lanthanide ions (Ce, Pr,..., Eu,...Yb, Lu) in wide band gap inorganic compounds like YPO 4 and CaF II is applied to locate lanthanide levels in the wideband semiconductors GaN, AlN, their solid solutions Al xGa 1-xN, and ZnO. The proposed schemes provide a description of relevant optical and luminescence properties of these lanthanide doped semiconductors. Especially, the relation between thermal quenching of Tb 3+ emission and the location of the energy levels is explained.

Dorenbos, P.; van der Kolk, E.

2007-02-01

365

Improved feedback shift register  

NASA Technical Reports Server (NTRS)

Design of feedback shift register with three tap feedback decoding scheme is described. Application for obtaining sequence synchronization patterns is examined. Operation of the circuitry is described and drawings of the systems are included.

Perlman, M.

1972-01-01

366

Molecular Electronic Shift Registers  

NASA Technical Reports Server (NTRS)

Molecular-scale shift registers eventually constructed as parts of high-density integrated memory circuits. In principle, variety of organic molecules makes possible large number of different configurations and modes of operation for such shift-register devices. Several classes of devices and implementations in some specific types of molecules proposed. All based on transfer of electrons or holes along chains of repeating molecular units.

Beratan, David N.; Onuchic, Jose N.

1990-01-01

367

Preparation of N,N-dialkylcarbamato lanthanide complexes by extraction of lanthanide ions from aqueous solution into hydrocarbons.  

PubMed

Lanthanides are easily extracted as N,N-dibutylcarbamato complexes from aqueous solutions of their chlorides into heptane solutions of dibutylamine saturated with CO2. The products are recovered in high yields and are soluble in hydrocarbons. The derivatives [Ln(O2CNBu2)3]n [Ln = Nd (1), Eu (2), Tb (3)], [NH2Bu2]2[Ln4(CO3)(O2CNBu2)12] [Ln = Tb (4), Sm (5), Eu (6)], and [Sm4(CO3)(O2CNBu2)10], 7, have thus been obtained. The crystal and molecular structure of 4 has been solved; the samarium and europium complexes 5 and 6 were found to be isostructural. Mass spectra of the complexes 1-3, 4, and 7 (in MeCN/toluene) reveal that equilibria are present in solution. Compound 2 has been reacted in toluene with NHBz2 in the presence of CO2 affording [NH2Bz2][Eu(O2CNBz2)4], 8, through a ligand exchange process. By thermal treatment, 8 afforded [Eu(O2CNBz2)3]n, 9. With a similar procedure [Sm(O2CNBz2)3]n, 10, was obtained from 5. According to the photoluminescence study carried out on solid samples of 2, 4, 5, 7, and 8, the metal centered f-f transitions represent the only effective way to induce lanthanide luminescence in these complexes. PMID:24779510

Armelao, Lidia; Belli Dell'Amico, Daniela; Biagini, Paolo; Bottaro, Gregorio; Chiaberge, Stefano; Falvo, Paola; Labella, Luca; Marchetti, Fabio; Samaritani, Simona

2014-05-19

368

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

Code of Federal Regulations, 2014 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3390 Neisseria spp. direct serological test reagents....

2014-04-01

369

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

Code of Federal Regulations, 2010 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3390 Neisseria spp. direct serological test reagents....

2010-04-01

370

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

Code of Federal Regulations, 2011 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3390 Neisseria spp. direct serological test reagents....

2011-04-01

371

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

PubMed

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. PMID:22960691

Fridley, Gina E; Le, Huy Q; Fu, Elain; Yager, Paul

2012-11-01

372

Iron- and Cobalt-Catalyzed Arylation of Azetidines, Pyrrolidines, and Piperidines with Grignard Reagents.  

PubMed

Iron- and cobalt-catalyzed cross-couplings between iodo-azetidines, -pyrrolidines, -piperidines, and Grignard reagents are disclosed. The reaction is efficient, cheap, chemoselective and tolerates a large variety of (hetero)aryl Grignard reagents. PMID:25401684

Barré, Baptiste; Gonnard, Laurine; Campagne, Rémy; Reymond, Sébastien; Marin, Julien; Ciapetti, Paola; Brellier, Marie; Guérinot, Amandine; Cossy, Janine

2014-11-17

373

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. PMID:22960691

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

2012-01-01

374

Candidate Reagents for Dissolution of Hanford Site Tank Sludges-Scoping Studies with Simulants Using Single Reagents and Their Mixtures  

SciTech Connect

Chemical agents were investigated for their efficacies in dissolving metal compound phases known to be present in Hanford tank waste sludges. The phases included Fe(OH)3, Cr(OH)3, Al(OH)3, MnO2, and Na2U2O7. In conjunction with laboratory testing, a survey of the technical literature also was performed to identify candidate reagents. The tests were conducted in three campaigns. First, scoping tests investigated individual agents identified in the literature review along with other candidate agents. Based on the scoping test results, follow-up testing was performed to investigate the efficacies of mixed citric/oxalic acids (CITROX) and mixed nitric/oxalic acids (NITROX). Overall, oxalic acid is the most effective single reagent, dissolving all of the solid phases to some extent. However, for MnO2 and Na2U2O7, reprecipitation soon followed dissolution. The MnO2 also oxidized at least two of organic acids tested, oxalic acid and citric acid, as shown by the evolution of gas during the tests with these reagents. The CITROX and NITROX tests failed to show beneficial synergistic effects in dissolving sludge phases. Instead, the findings suggest that the sequential addition of individual pure reagents (e.g., first citric acid to dissolve MnO2 and Na2U2O7 and removal of the solution followed by oxalic acid to dissolve the Fe, Cr, and Al hydroxides) may be more effective than individual or blended reagents.

Sinkov, Serguei I.

2003-08-25

375

Modelling studies in aqueous solution of lanthanide (III) chelates designed for nuclear magnetic resonance biomedical applications  

NASA Astrophysics Data System (ADS)

Molecular dynamics simulations and complementary modelling studies have been carried out for the [Gd(DOTA)·(H2O)]- and [Tm(DOTP)]5- chelates in aqueous media, to provide a better understanding of several structural and dynamical properties of these versatile nuclear magnetic resonance (NMR) probes, including coordination shells and corresponding water exchange mechanisms, and interactions of these complexes with alkali metal ions. This knowledge is of key importance in the areas of 1H relaxation and shift reagents for NMR applications in medical diagnosis. A new refinement of our own previously developed set of parameters for these Ln(III) chelates has been used, and is reported here. Calculations of water mean residence times suggest a reassessment of the characterization of the chelates' second coordination shell, one where the simple spherical distribution model is discarded in favour of a more detailed approach. Na+ probe interaction maps are in good agreement with the available site location predictions derived from 23Na NMR shifts.

Henriques, E. S.; Geraldes, C. F. G. C.; Ramos, M. J.

376

Determination of the concentrations of the steroids estradiol, progesterone and testosterone in bovine sera: comparison of commercial dissociation enhanced lanthanide fluorescence immunoassay kits with conventional radio and enzyme immunoassays.  

PubMed

The performance of three conventional enzyme and radioimmunoassays routinely used to detect residues of anabolic steroids in cattle sera were compared with dissociation enhanced lanthanide fluorescence immunoassay (DELFIA) kits designed for the hospital market. Slight modifications to the kit reagents were required for the analysis of bovine sera. Owing to the large sample volumes used in conventional assays, detection limits were generally better than those obtained with DELFIA kits, however, assay reproducibility was enhanced using the DELFIA technology. Comparison of sera obtained from cattle implanted with anabolic steroids revealed a good correlation between alternate methods (r2 from 0.91 to 0.97). The DELFIA kits offer a faster method for measuring estradiol, progesterone and testosterone with adequate sensitivity and in a safer environment than that encountered using radioimmunoassays. PMID:7604958

Elliott, C T; Francis, K S; Shortt, H D; McCaughey, W J

1995-06-01

377

Postsynthetic lanthanide functionalization of nanosized metal-organic frameworks for highly sensitive ratiometric luminescent thermometry.  

PubMed

A straightforward postsynthetic lanthanide functionalization strategy is developed for fabricating highly sensitive ratiometric luminescent nanothermometers based on nanosized MOFs, which highlights the ability of a broad range of nanosized MOFs to construct nanothermometers. PMID:25345472

Zhou, You; Yan, Bing; Lei, Fang

2014-12-14

378

Equilibrium speciation of select lanthanides in the presence of acidic ligands in homo- and heterogeneous solutions.  

E-print Network

??This dissertation explores lanthanide speciation in liquid solution systems related to separation schemes involving the acidic ligands: bis(2-ethylhexyl) phosphoric acid (HDEHP), lactate, and 8-hydroxyquinoline. Equilibrium… (more)

Robinson, Troy

2011-01-01

379

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

PubMed Central

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

Yoo, Byunghee; Pagel, Mark D.

2014-01-01

380

IA PERIODIC TABLE OF THE ELEMENTS VillA lanthanide Series  

E-print Network

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

Hazen, Terry

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

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

SciTech Connect

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

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

2013-04-08

383

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

E-print Network

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

Barthelmes, Katja

384

Separation and quantitative determination of the cerium group lanthanides by gas-liquid chromatography.  

PubMed

A gas chromatographic method is reported for the separation and subsequent quantitative determination of the cerium group lanthanides. The lanthanides (RE) are synergistically extracted from aqueous solution with the polyfluorinated beta-diketone 1,1,1,2,2,6,6,7,7,7-decafluoro-3,5-heptanedione, H(FHD), as ligand, and di-n-butylsulphoxide, DBSO, as neutral donor. The composition of the extracted species is reported to be RE(FHD)(3) .2DBSO. Thermogravimetric analysis of the complexes is reported. Analytical curves were prepared and found to be usable over the range of 0.1-10 mug of metal. Individual lanthanides were determined with 99.0 % recovery with a relative mean deviation of +/-2.0%. Mixture of lanthanides were analyzed with 101.2% recovery with a relative mean deviation of +/-2.2%. PMID:18961290

Burgett, C A; Fritz, J S

1973-04-01

385

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

PubMed

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

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

2014-10-20

386

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

PubMed

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

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

2014-10-01

387

Swine Toolkit Plans and Progress for the US Veterinary Immune Reagent Network  

Technology Transfer Automated Retrieval System (TEKTRAN)

The US Veterinary Immune Reagent Network (http://www.umass.edu/vetimm/) was established to address the lack of immunological reagents specific for ruminant, porcine, poultry, equine and aquaculture species and accordingly has set a minimum goal of 20 reagents per species group. Current plans are to...

388

Adding reagent to droplets with controlled rupture of encapsulated double emulsions  

PubMed Central

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

Sciambi, Adam; Abate, Adam R.

2013-01-01

389

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

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Cell-freezing apparatus and reagents for...Blood and Blood Products § 864.9225 Cell-freezing apparatus and reagents for in...diagnostic use. (a) Identification. Cell-freezing apparatus and reagents...

2012-04-01

390

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

Code of Federal Regulations, 2010 CFR

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

2010-04-01

391

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

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Cell-freezing apparatus and reagents for...Blood and Blood Products § 864.9225 Cell-freezing apparatus and reagents for in...diagnostic use. (a) Identification. Cell-freezing apparatus and reagents...

2013-04-01

392

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

Code of Federal Regulations, 2011 CFR

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

2011-04-01

393

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

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Cell-freezing apparatus and reagents for...Blood and Blood Products § 864.9225 Cell-freezing apparatus and reagents for in...diagnostic use. (a) Identification. Cell-freezing apparatus and reagents...

2014-04-01

394

Edinburgh Research Explorer Selection of boron reagents for Suzuki-Miyaura coupling  

E-print Network

Edinburgh Research Explorer Selection of boron reagents for Suzuki-Miyaura coupling Citation for published version: Lennox, AJJ & Lloyd-Jones, GC 2014, 'Selection of boron reagents for Suzuki.1039/c3cs60197h Selection of boron reagents for Suzuki­Miyaura coupling Alastair J. J. Lennox and Guy C

Millar, Andrew J.

395

Crystal growth of inter-lanthanide La Ln'O 3 ( Ln' = Y, Ho-Lu) perovskites from hydroxide fluxes  

NASA Astrophysics Data System (ADS)

In this article, we report the growth of single crystals of the inter-lanthanide series La Ln'O 3 ( Ln' = Y, Ho-Lu) using molten hydroxide fluxes. Inter-lanthanide oxides, LnLn'O 3 (where Ln and Ln' = lanthanides) typically crystallize in the A-, B- or C-Ln2O3 or in the ABO 3 perovskite structure types, depending on the relative sizes of the lanthanide cations involved. The inter-lanthanide oxides, La Ln'O 3 ( Ln' = Y, Ho-Lu), reported herein were determined to crystallize in the orthorhombic ( Pnma) perovskite-type structure. A discussion on the effect of cation radii on the resultant crystal structure for La Ln'O 3 ( Ln' = Y, Ho-Lu) and other reported inter-lanthanide oxides is presented herein.

Bharathy, M.; Fox, Adam H.; Mugavero, S. J.; zur Loye, H.-C.

2009-03-01

396

Protein Chemical Shift Prediction  

E-print Network

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

Larsen, Anders S

2014-01-01

397

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

PubMed

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 1,286 and 1,600 degrees 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 is not strongly affected by the type of lanthanide. The results were correlated with defect energy calculations of the lanthanide diffusion enthalpy using the Mott-Littleton approach. An association enthalpy of cation vacancies with oxygen vacancies of about 1 eV (96 kJ/mol) was deduced in the case of CSZ, while there is no association in the case of YSZ. Furthermore, the change in diffusion coefficients can be correlated to the interaction parameter for the interaction between the lanthanide oxide with zirconia: The higher the interaction parameter, the higher the lanthanide diffusion coefficient. PMID:15352843

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

2004-09-15

398

Rapid transdermal bloodless and reagent-free malaria detection  

NASA Astrophysics Data System (ADS)

Successful diagnosis, screening, and elimination of malaria critically depend on rapid and sensitive detection of this dangerous infection, preferably transdermally and without sophisticated reagents or blood drawing. Such diagnostic methods are not currently available. Here we show that the high optical absorbance and nanosize of endogenous heme nanoparticles called hemozoin, a unique component of all blood-stage malaria parasites, generate a transient vapor nanobubble around hemozoin in response to a short and safe near-infrared picosecond laser pulse. The acoustic signals of these malaria-specific nanobubbles provided the first transdermal non-invasive and rapid detection of a malaria infection as low as 0.00034% in animals without using any reagents or drawing blood. These on-demand transient events have no analogs among current malaria markers and probes, can detect and screen malaria in seconds and can be realized as a compact, easy to use, inexpensive and safe field technology.

Lukianova-Hleb, Ekaterina Y.; Campbell, Kelly M.; Constantinou, Pamela E.; Braam, Janet; Olson, John S.; Ware, Russell E.; Sullivan, David S.; Lapotko, Dmitri

2014-02-01

399

Chemical oxidation of BTX using Fenton`s reagent  

SciTech Connect

Fenton`s reagent has proven to be an economically feasible and effective oxidant to destruct an extensive variety of hazardous wastes. In this work, benzene, toluene and xylene (BTX) were selected as model compounds subjected to oxidation using Fenton`s regent under batch conditions. Various factors deemed critical in optimizing the oxidation of organics were studied. Test results indicated that BTX can be effectively oxidized in aqueous solutions with Fenton`s reagent. At a H{sub 2}O{sub 2}: BTX: Fe{sup +2} ratio of 12; 1: 60 (mg/L), the dissolved BTX can be completely removed in a period less than ten minutes. A rate equation was derived for predicting the residual concentration of BTX in terms of the contact time. 19 refs., 8 figs.

Lou, J.C.; Lee, S.S. [National Sun Yat-Sen Univ., Kaohsiung (Taiwan, Province of China)

1995-12-31

400

Shelf Life of Fluorescent Treponemal Antibody-Absorption Test Reagents  

PubMed Central

Properly prepared, standarized, and stored fluorescent treponemal antibody-absorption (FTA-ABS) reagents have been shown to have stabilities equal to other biological reagents. A liquid antigen over 10 years old has been shown to give a satisfactory reaction. Newer preparations have now been shown to be stable for over 5 years, and the tests on each are being continued. The very new liquid antigens which were originally standardized by the FTA-ABS method have shown no decrease in potency over a 20-month period. Stability studies on antigens dried on slides are now in their eighth month, with no apparent loss in potency. The stability of the conjugate is constant when stored frozen at ?20 C or lyophilized. When stored as a liquid at 4 C, the stability is governed by the pH and the molarity of the buffer. The standardized and lyophilized sorbent has been shown to be stable for over 1 year. PMID:4882013

Roberts, Merritt E.; Miller, James N.; Pringle, Thomas C.; Binnings, Gerald F.

1968-01-01

401

Degradation of carbon tetrachloride by modified Fenton's reagent.  

PubMed

The degradation of tetrachloromethane (carbon tetrachloride-CT) by modified Fenton's reagent (catalyzed hydrogen peroxide) was investigated using a range of hydrogen peroxide concentrations and 1 mM iron(III) catalyst. The documented reactive species in modified Fenton's reactions, hydroxyl radical (OH*), is not reactive with CT, yet CT degradation was observed in the Fenton's reactions and was confirmed by chloride generation. Because CT is not reactive with OH*, a reductive mechanism which may involve superoxide radical anion is proposed for CT degradation in modified Fenton's systems. Scavenging of reductants by excess chloroform prevented CT degradation, confirming a reductive mechanism. Similar to CT, three other oxidized aliphatic compounds, hexachloroethane, bromotrichloromethane, and tetranitromethane, were also degraded by modified Fenton's reagent. The results show that modified Fenton's reactions act through a reductive mechanism to degrade compounds that are not reactive with OH*, which broadens the scope of this process for hazardous waste treatment and remediation. PMID:12169420

Teel, Amy L; Watts, Richard J

2002-10-01

402

Catalytic asymmetric addition of diorganozinc reagents to N-phosphinoylalkylimines  

PubMed Central

The synthesis of ?-chiral amines bearing two alkyl groups has been hampered by the accessibility and stability of the alkylimine precursor. Herein, we report an efficient strategy to generate the alkyl-substituted imine in situ that is compatible with the Me-DuPHOS monoxide·Cu(I) catalyzed addition of diorganozinc reagents. The sulfinic acid adduct of the imine is readily prepared by mixing diphenylphosphinic amide, the aldehyde, and sulfinic acid. The sulfinic acid adduct is generally isolated by filtration. The addition of diorganozinc reagents in the presence of Me-DuPHOS monoxide·Cu(I) and the in situ-generated imines affords the corresponding ?-chiral amines in high yields and enantiomeric excesses. PMID:15064400

Côté, Alexandre; Boezio, Alessandro A.; Charette, André B.

2004-01-01

403

Behavior of a chlorinated ethene plume following source-area treatment with Fenton's reagent  

USGS Publications Warehouse

Monitoring data collected over a 6-year period show that a plume of chlorinated ethene-contaminated ground water has contracted significantly following treatment of the contaminant source area using in situ oxidation. Prior to treatment (1998), concentrations of perchloroethene (PCE) exceeded 4500 ??g/L in a contaminant source area associated with a municipal landfill in Kings Bay, Georgia. The plume emanating from this source area was characterized by vinyl chloride (VC) concentrations exceeding 800 ??g/L. In situ oxidation using Fenton's reagent lowered PCE concentrations in the source area below 100 ??g/L, and PCE concentrations have not rebounded above this level since treatment. In the 6 years following treatment, VC concentrations in the plume have decreased significantly. These concentration declines can be attributed to the movement of Fenton's reagent-treated water downgradient through the system, the cessation of a previously installed pump-and-treat system, and the significant natural attenuation capacity of this anoxic aquifer. While in situ oxidation briefly decreased the abundance and activity of microorganisms in the source area, this activity rebounded in <6 months. Nevertheless, the shift from sulfate-reducing to Fe(III)-reducing conditions induced by Fenton's treatment may have decreased the efficiency of reductive dechlorination in the injection zone. The results of this study indicate that source-area removal actions, particularly when applied to ground water systems that have significant natural attenuation capacity, can be effective in decreasing the areal extent and contaminant concentrations of chlorinated ethene plumes. Copyright ?? 2005 National Ground Water Association.

Chapelle, F.H.; Bradley, P.M.; Casey, C.C.

2005-01-01

404

Atomic Layer Deposition of Lanthanide Oxides: Exemplified by Europium Oxide  

NASA Astrophysics Data System (ADS)

Lanthanide oxides are important components in a range of optoelectronical materials such as lasers, diodes and light conversion materials. We have investigated the possibilities to use atomic layer deposition (ALD) for deposition of thin films of of the Ln2O3 (Ln = Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb) systems using the precursor combinations Ln(thd)3 + O3 (thd = 2,2,6,6-tetramethyl-3,5-dionato). The advantage of ALD is the possibilities of mixing different materials at the atomic level and at relatively low temperatures. This opens for synthesis of many new materials where controlled intermixing of elements is important. The results from this work have been used to deposit down conversion films based on europium doped titanium oxide.

Hansen, Per-Anders; Finstad, T.; Fjellvåg, H.; Nilsen, O.

405

Supramolecular luminescent lanthanide dimers for fluoride sequestering and sensing.  

PubMed

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

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

2014-07-01

406

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

407

Gold Coated Lanthanide Phosphate Nanoparticles for Targeted Alpha Generator Radiotherapy  

PubMed Central

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

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

2013-01-01

408

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

409

Catalytic degradation of nitroaromatic explosives with Fenton's reagent  

Microsoft Academic Search

Oxidation of the nitroaromatic explosives namely, 2,4,6-trinitrophenol (PA), ammonium picrate (AP), 2,4-dinitrotoluene (DNT) and 2,4,6-trinitrotoluene (TNT) by Fenton's reagent has been investigated in this study. The initial concentrations of nitroaromatics were in the range of 1.0×10?5 to 3.0×10?4M. For the Fenton oxidation of the four nitroaromatics, the structural characteristic is the major factor affecting the decomposition rate rather than the

Ming-Jer Liou; Ming-Chun Lu

2007-01-01

410

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

411

Functionalization of heterocyclic compounds using polyfunctional magnesium and zinc reagents  

PubMed Central

Summary In this review we summarize the most important procedures for the preparation of functionalized organzinc and organomagnesium reagents. In addition, new methods for the preparation of polyfunctional aryl- and heteroaryl zinc- and magnesium compounds, as well as new Pd-catalyzed cross-coupling reactions, are reported herein. Experimental details are given for the most important reactions in the Supporting Information File 1 of this article. PMID:21977211

Schade, Matthias A; Bernhardt, Sebastian; Manolikakes, Georg; Metzger, Albrecht; Piller, Fabian M; Rohbogner, Christoph J; Mosrin, Marc

2011-01-01

412

Robotic system for preparing reagent and dilution vials  

Microsoft Academic Search

A robotic system has been developed for repetitively filling dilution and reagent vials in the 772-F Laboratory Facility of SRP. Approximately 10,000 vials per month (may range from 6000 to 16,000) are filled with standard volumes of HNOâ, Al(NOâ)â, or KSCN for use in analyzing process samples from 221-F and 221-H. The intent of this system is to provide an

Dyches

1984-01-01

413

Extraction of Gold and Silver by Thiourea-Based Reagents  

Microsoft Academic Search

The synthesis and properties of some novel solvent extractants that are highly selective for gold and silver in very acidic chloride solutions are described. In this paper we also report on the study of one of these reagents; Dodecyl-thiourea (DTH), which has shown to be a very selective extractant for Au(III) and Ag(I) in the presence of Cu(II) and Fe(III).

Guangju Zuo; Mamoun Muhammed

1990-01-01

414

Reagent Selection Methodology for a Novel Explosives Detection Platform  

ScienceCinema

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

None

2012-12-31

415

Oxidation kinetics and mechanisms of trihalomethanes by Fenton's reagent  

Microsoft Academic Search

Oxidation kinetics and mechanisms of four trihalomethanes (THMs) commonly found in chlorinated drinking water by Fenton's reagent were investigated. All the experiments were carried out in air-tight and well-mixed batch reactors in which no headspace was allowed in order to minimize volatilization of any THM during reaction. The optimum dosages of H2O2 and Fe2+ in the oxidation of bromoform was

Walter Z. Tang; Stephanie Tassos

1997-01-01

416

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. PMID:9591648

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

1998-01-01

417

Facile sonochemical synthesis and photoluminescent properties of lanthanide orthophosphate nanoparticles  

SciTech Connect

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

Yu Cuicui; Yu Min [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Department of Chemistry, Northeast Normal University, Changchun 130024 (China); Li Chunxia; Liu Xiaoming; Yang Jun; Yang Piaoping [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Lin Jun [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)], E-mail: jlin@ciac.jl.cn

2009-02-15

418

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

419

Sulfhydryl reagents and energy-linked reactions in monocot thylakoids.  

PubMed

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

Cohen, W S; Baxter, D R

1990-07-01

420

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

421

Quantum Shift Register  

E-print Network

We consider a quantum circuit in which shift and rotation operations on qubits are performed by swap gates and controlled swap gates. These operations can be useful for quantum computers performing elementary arithmetic operations such as multiplication and a bit-wise comparison of qubits.

Jae-weon Lee; Eok Kyun Lee; Jaewan Kim; Soonchil Lee

2001-12-19

422

Evaluation of commercial serologic test reagents for immunoidentification of medically important aspergilli.  

PubMed

We evaluated commercial serodiagnostic test reagents from Greer Laboratories (GL), Lenoir, NC; Immuno-mycologics, Inc. (IMI), Norman, OK; and Scott Laboratories (SL), Fiskville, RI; for their ability to detect Aspergillus spp. exoantigens and group them in their proper series. We detected 87 culture extracts from coded cultures of Aspergillus groups and heterologous fungi against anti-A. fumigatus, A. flavus, A. nidulans, A. niger, and A. terreus sera in the presence of their corresponding antigens. Parallel control studies were performed using serological reagents from both laboratories. The IMI reagents accurately grouped all the isolates. The A. nidulans and A. terreus reactions, however, were significantly weaker than those noted with the control reagents. GL and SL do not supply A. nidulans and A. terreus reagents. Their available reagents correctly grouped the A. fumigatus, A. flavus, and A. niger isolates. Our results indicate that the commercial serodiagnostic reagents for aspergillosis can be effectively used to accurately immunoidentify the medically important Aspergillus spp. PMID:3126020

Sekhon, A S; Standard, P G; Kaufman, L; Garg, A K

1987-11-01

423

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

DOEpatents

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

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

2002-07-09

424

Intramolecular C-F and C-H bond cleavage promoted by butadienyl heavy Grignard reagents.  

PubMed

Organomagnesium compounds (Grignard reagents) are among the most useful organometallic reagents and have greatly accelerated the advancement of synthetic chemistry and related sciences. Nevertheless, heavy Grignard reagents based on the metals calcium, strontium or barium are not widely used, mainly due to their rather inert heavy alkaline-earth metals and extremely high reactivity of their corresponding Grignard-type reagents. Here we report the generation and reaction chemistry of butadienyl heavy Grignard reagents whose extremely high reactivity is successfully tamed. Facile synthesis of perfluoro-?-extended pentalene and naphthalene derivatives is realized by the in situ generated heavy Grignard reagents via intramolecular C-F/C-H bond cleavage. These obtained perfluorodibenzopentalene and perfluorodinaphthopentalene derivatives show low-lying LUMO levels, with one being the lowest value so far among all pentalene derivatives. Our results set an exciting example for the meaningful synthetic application of heavy Grignard reagents. PMID:25047678

Li, Heng; Wang, Xiao-Ye; Wei, Baosheng; Xu, Ling; Zhang, Wen-Xiong; Pei, Jian; Xi, Zhenfeng

2014-01-01

425

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

426

Ambiguous red shifts  

NASA Astrophysics Data System (ADS)

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

Wulfman, Carl E.

2010-12-01

427

The electronic level structure of lanthanide impurities in REPO4, REBO3, REAlO3, and RE2O3 (RE = La, Gd, Y, Lu, Sc) compounds  

NASA Astrophysics Data System (ADS)

The vacuum referred binding energies of electrons in divalent and trivalent lanthanide impurity states and host band states in the rare earth (RE = La, Gd, Y, Lu, Sc) orthophosphates REPO4, orthoborates REBO3, aluminum perovskites REAlO3, and sesqui-oxides RE2O3 have been determined by combining the recently developed chemical shift model with spectroscopic data from the archival literature. The main trends in impurity and host band level locations with changing type of RE, which determines the site size, and with changing P, B, Al, or RE cation, which determines the strength of bonding with the oxygen ligands, are identified. Sc3+-based compounds are characterized by a relatively low energy for the conduction band bottom, or equivalently a high electron affinity, which is attributed to a relatively strong electron bonding in the 3d-shell of Sc2+.

Dorenbos, Pieter

2013-06-01

428

Fully fluorinated imidodiphosphinate shells for visible- and NIR-emitting lanthanides: hitherto unexpected effects of sensitizer fluorination on lanthanide emission properties.  

PubMed

In this paper we demonstrate that the effect of aromatic C--F substitution in ligands does not always abide by conventional wisdom for ligand design to enhance sensitisation for visible lanthanide emission, in contrast with NIR emission for which the same effect coupled with shell formation leads to unprecedented long luminescence lifetimes. We have chosen an imidodiphosphinate ligand, N-{P,P-di(pentafluorophinoyl)}-P,P-dipentafluorophenylphosphinimidic acid (HF20tpip), to form ideal fluorinated shells about all visible- and NIR-emitting lanthanides. The shell, formed by three ligands, comprises twelve fully fluorinated aryl sensitiser groups, yet no-high energy X--H vibrations that quench lanthanide emission. The synthesis, full characterisation including X-ray and NMR analysis as well as the photophysical properties of the emissive complexes [Ln(F20tpip)3], in which Ln=Nd, Sm, Eu, Gd, Tb, Dy, Er, Yb, Y, Gd, are reported. The photophysical results contrast previous studies, in which fluorination of alkyl chains tends to lead to more emissive lanthanide complexes for both visible and NIR emission. Analysis of the fluorescence properties of the HF20tpip and [Gd(F20tpip)3] reveals that there is a low-lying state at around 715 nm that is responsible for partially quenching of the signal of the visible emitting lanthanides and we attribute it to a pi-sigma* state. However, all visible emitting lanthanides have long lifetimes and unexpectedly the [Dy(F20tpip)3] complex shows a lifetime of 0.3 ms, indicating that the elimination of high-energy vibrations from the ligand framework is particularly favourable for Dy. The NIR emitting lanthanides show strong emission signals in powder and solution with unprecedented lifetimes. The luminescence lifetimes of [Nd(F20tpip)3], [Er(F20tpip)3] and [Yb(F20tpip)3] in deuteurated acetonitrile are 44, 741 and 1111 micros. The highest value observed for the [Yb(F20tpip)3] complex is more than half the value of the Yb ion radiative lifetime. PMID:17570719

Glover, Peter B; Bassett, Andrew P; Nockemann, Peter; Kariuki, Benson M; Van Deun, Rik; Pikramenou, Zoe

2007-01-01

429

Water Gas Shift Catalysis  

Microsoft Academic Search

Developments in water gas shift (WGS) catalysis, especially during the last decade, are reviewed. Recent developments include the development of 1 chromium?free catalysts that can operate at lower steam to gas ratios and 2 more active catalysts that can operate at gas hourly space velocities above 40,000 h. A current challenge is to develop catalysts for use in fuel cell applications.

Chandra Ratnasamy; Jon P. Wagner

2009-01-01

430

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

431

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

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

432

Desalting protein ions in native mass spectrometry using supercharging reagents.  

PubMed

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

Cassou, Catherine A; Williams, Evan R

2014-10-01

433

Chemical reagents for investigating the major groove of DNA.  

PubMed

Chemical modification provides an inexpensive and rapid method for characterizing the structure of DNA and its association with drugs and proteins. Numerous conformation-specific probes are available, but most investigations rely on only the most common and readily available of these. The major groove of DNA is typically characterized by reaction with dimethyl sulfate, diethyl pyrocarbonate, potassium permanganate, osmium tetroxide, and, quite recently, bromide with monoperoxysulfate. This commentary discusses the specificity of these reagents and their applications in protection, interference, and missing contact experiments. PMID:18428867

Rokita, S E

2001-08-01

434

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

435

Synthesis and structural characterization of nonanuclear lanthanide complexes.  

PubMed

A series of nonanuclear lanthanide oxo-hydroxo complexes of the general formula [Ln(9)(mu(4)-O)(2)(mu(3)-OH)(8)(mu-BA)(8)(BA)(8)](-)[HN(CH(2)CH(3))(3)](+).(CH(3)OH)(2)(CHCl(3)) (BA = benzoylacetone; Ln = Sm, 1; Eu, 2; Gd, 3; Dy, 4; Er, 5) were prepared by the reaction of hydrous lanthanide trichlorides with benzoylacetone in the presence of triethylamine in methanol and recrystallized from chloroform/methanol (1:10) at room temperature. These five compounds are isomorphous. Crystal data for 1: cubic, Pn3n; T = 180 K; a = 33.8652(4) A; V = 38838.4(8) A(3); Z = 6; D(calcd) = 1.125 g cm(-)(3); R1 = 3.37%. Crystal data for 2: cubic, Pn3n; T = 180 K; a = 33.8252(8) A; V = 38700.9(16) A(3); Z = 6; D(calcd) = 1.133 g cm(-)(3); R1 = 4.97%. Crystal data for 3: cubic, Pn3n; T = 180 K; a = 33.7061(6) A; V = 38293.5(12) A(3); Z = 6; D(calcd) = 1.157 g cm(-)(3); R1 = 5.13%. Crystal data for 4: cubic, Pn3n; T = 180 K; a = 33.5900(7) A; V = 37899.2(14) A(3); Z = 6; D(calcd) = 1.182 g cm(-)(3); R1 = 4.03%. Crystal data for 5: cubic, Pn3n; T = 180 K; a = 33.5054(8) A; V = 37613.6(16) A(3); Z = 6; D(calcd) = 1.202 g cm(-)(3); R1 = 4.86%. The core of the anionic cluster comprises two vertex-sharing square-pyramidal [Ln(5)(mu(4)-O)(mu(3)-OH)(4)](9+) units. The compounds were characterized by elemental analysis, IR, fast atom bombardment mass spectra, thermogravimetry, and differential scanning calorimetry. The thermal analysis indicated that the nonanuclear species were stable up to 150 degrees C. Luminescence spectra of 2 and magnetic properties of 1-5 were also studied. PMID:12470077

Xu, Gang; Wang, Zhe-Ming; He, Zheng; Lü, Zhi; Liao, Chun-Sheng; Yan, Chun-Hua

2002-12-16

436

New crystal structural families of lanthanide chloride alcohol/water complexes  

SciTech Connect

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

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

2012-01-01

437

Labile Capping Bonds in Lanthanide(III) Complexes: Shorter and Weaker.  

PubMed

For a wide range of trivalent lanthanide ion coordination complexes of tricapped trigonal prism or monocapped square antiprism configurations, the bonds between the central lanthanide ions and the capping ligands are found to violate Badger's rule: they can get weaker as they get shorter. We demonstrate that this observation originates from the screening and repulsion effect of the prism ligands. Both effects enhance as the electric field of the central ion or the softness of the prism ligands increases. Thus, for heavier lanthanides, despite the fact that the capping bond could be shorter, it is more efficient to be weakened by the prism ligands, being inherently labile. This concept of "labile capping bonds phenomenon" is then successfully used to interpret many problems in lanthanide(III) hydration, e.g., why the water exchange rate of a lanthanide(III) complex is much higher in a twisted square antiprism than in square antiprism configuration. Thus, the theory proposed in this paper offers new insights in understanding chemical problems. PMID:25547783

Zhang, Jun; Dolg, Michael

2015-01-29

438

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

2012-03-21

439

Use of lanthanides to alleviate the effects of metal ion-deficiency in Desmodesmus quadricauda (Sphaeropleales, Chlorophyta)  

PubMed Central

Lanthanides are biologically non-essential elements with wide applications in technology and industry. Their concentration as environmental contaminants is, therefore, increasing. Although non-essential, lanthanides have been proposed (and even used) to produce beneficial effects in plants, even though their mechanisms of action are unclear. Recently, it was suggested that they may replace essential elements. We tested the effect of low concentrations of lanthanides on the common freshwater microalga Desmodesmus quadricauda, grown under conditions of metal ion-deficiency (lower calcium or manganese concentrations). Our goal was to test if lanthanides can replace essential metals in their functions. Physiological stress was recorded by studying growth and photosynthetic activity using a pulse amplitude modulation (PAM) fluorimeter. We found that nutrient stress reduced parameters of growth and photosynthesis, such as maximal quantum yield, relative electron transport rate, photon capturing efficiency and light saturation irradiance. After adding low concentrations of five lanthanides, we confirmed that they can produce a stimulatory effect on microalgae, depending on the nutrient (metal) deprivation. In the case of a calcium deficit, the addition of lanthanides partly alleviated the adverse effects, probably by a partial substitution of the element. In contrast, with manganese deprivation (and at even lower concentrations), lanthanides enhanced the deleterious effect on cellular growth and photosynthetic competence. These results show that lanthanides can replace essential elements, but their effects on microalgae depend on stress and the nutritional state of the microalgae, raising the possibility of environmental impacts at even low concentrations. PMID:25674079

Goecke, Franz; Jerez, Celia G.; Zachleder, Vilém; Figueroa, Félix L.; Bišová, Kate?ina; ?ezanka, Tomáš; Vítová, Milada

2015-01-01

440

Use of lanthanides to alleviate the effects of metal ion-deficiency in Desmodesmus quadricauda (Sphaeropleales, Chlorophyta).  

PubMed

Lanthanides are biologically non-essential elements with wide applications in technology and industry. Their concentration as environmental contaminants is, therefore, increasing. Although non-essential, lanthanides have been proposed (and even used) to produce beneficial effects in plants, even though their mechanisms of action are unclear. Recently, it was suggested that they may replace essential elements. We tested the effect of low concentrations of lanthanides on the common freshwater microalga Desmodesmus quadricauda, grown under conditions of metal ion-deficiency (lower calcium or manganese concentrations). Our goal was to test if lanthanides can replace essential metals in their functions. Physiological stress was recorded by studying growth and photosynthetic activity using a pulse amplitude modulation (PAM) fluorimeter. We found that nutrient stress reduced parameters of growth and photosynthesis, such as maximal quantum yield, relative electron transport rate, photon capturing efficiency and light saturation irradiance. After adding low concentrations of five lanthanides, we confirmed that they can produce a stimulatory effect on microalgae, depending on the nutrient (metal) deprivation. In the case of a calcium deficit, the addition of lanthanides partly alleviated the adverse effects, probably by a partial substitution of the element. In contrast, with manganese deprivation (and at even lower concentrations), lanthanides enhanced the deleterious effect on cellular growth and photosynthetic competence. These results show that lanthanides can replace essential elements, but their effects on microalgae depend on stress and the nutritional state of the microalgae, raising the possibility of environmental impacts at even low concentrations. PMID:25674079

Goecke, Franz; Jerez, Celia G; Zachleder, Vilém; Figueroa, Félix L; Bišová, Kate?ina; ?ezanka, Tomáš; Vítová, Milada

2015-01-01

441

Radiation resistance of biological reagents for in situ life detection.  

PubMed

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

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

2013-01-01

442

Enhancement of immunotoxin activity using chemical and biological reagents.  

PubMed

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

Wu, M

1997-01-01

443

Accessibility of the CLC-0 pore to charged methanethiosulfonate reagents.  

PubMed

Using the substituted-cysteine-accessibility method, we previously showed that a cysteine residue introduced to the Y512 position of CLC-0 was more rapidly modified by a negatively charged methanethiosulfonate (MTS) reagent, 2-sulfonatoethyl MTS (MTSES), than by the positively charged 2-(trimethylammonium)ethyl MTS (MTSET). This result suggests that a positive intrinsic pore potential attracts the negatively charged MTS molecule. In this study, we further test this hypothesis of a positive pore potential in CLC-0 and find that the preference for the negatively charged MTS is diminished significantly in modifying the substituted cysteine at a deeper pore position, E166. To examine this conundrum, we study the rates of MTS inhibitions of the E166C current and those of the control mutant current from E166A. The results suggest that the inhibition of E166C by intracellularly applied MTS reagents is tainted by the modification of an endogenous cysteine, C229, located at the channel's dimer interface. After this endogenous cysteine is mutated, CLC-0 resumes its preference for selecting MTSES in modifying E166C, reconfirming the idea that the pore of CLC-0 is indeed built with a positive intrinsic potential. These experiments also reveal that MTS modification of C229 can inhibit the current of CLC-0 depending on the amino acid placed at position 166. PMID:20141750

Zhang, Xiao-Dong; Yu, Wei-Ping; Chen, Tsung-Yu

2010-02-01

444

The Effect of Reagents Mimicking Oxidative Stress on Fibrinogen Function  

PubMed Central

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

Štikarová, Jana; Kotlín, Roman; Riedel, Tomáš; Suttnar, Ji?í; Pimková, Kristýna; Chrastinová, Leona; Dyr, Jan E.

2013-01-01

445

Microfluidic Screening of Electrophoretic Mobility Shifts Elucidates Riboswitch Binding Function  

PubMed Central

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 bench top assays (3.2 min vs. 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 (Kd) for both rapidly and slowly interconverting riboswitch-ligand pairs as validated through experiments and modeling. Conformational change, triplicate mobility shift measurements, and Kd 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.

2013-01-01

446

Ultrasmall lanthanide-doped nanoparticles as multimodal platforms  

NASA Astrophysics Data System (ADS)

Recently, there has been a great amount of interest in nanoparticles which are able to provide a platform with high contrast for multiple imaging modalities in order to advance the tools available to biomedical researchers and physicians. However, many nanoparticles do not have ideal properties to provide high contrast in different imaging modes. In order to address this, ultrasmall lanthanide doped oxide and fluoride nanoparticles with strong NIR to NIR upconversion fluorescence and a strong magnetic response for magnetic resonance imaging (MRI) have been developed. Specifically, these nanoparticles incorporate gadolinium, dysprosium, or a combination of both into the nano-crystalline host to achieve the magnetic properties. Thulium, erbium, and neodymium codopants provide the strong NIR absorption and emission lines that allow for deeper tissue imaging since near infrared light is not strongly absorbed or scattered by most tissues within this region. This also leads to better image quality and lower necessary excitation intensities. As a part of the one pot synthesis, these nanoparticles are coated with peg, pmao, or d-glucuronic acid to make them water soluble, biocompatible, and bioconjugable due to the available carboxyl or amine groups. Here, the synthesis, morphological characterization, magnetic response, NIR emission, and the quantum yield will be discussed. Cytotoxicity tested through cell viability at varying concentrations of nanoparticles in growth media will also be discussed.

Yust, Brian G.; Pedraza, Francisco J.; Sardar, Dhiraj K.

2014-03-01

447

Effect of lanthanide complex structure on cell viability and association.  

PubMed

A systematic study of the effect of hydrophobicity and charge on the cell viability and cell association of lanthanide metal complexes is presented. The terbium luminescent probes feature a macrocyclic polyaminocarboxylate ligand (DOTA) in which the hydrophobicity of the antenna and that of the carboxyamide pendant arms are independently varied. Three sensitizing antennas were investigated in terms of their function in vitro: 2-methoxyisophthalamide (IAM(OMe)), 2-hydroxyisophthalamide (IAM), and 6-methylphenanthridine (Phen). Of these complexes, Tb-DOTA-IAM exhibited the highest quantum yield, although the higher cell viability and more facile synthesis of the structurally related Tb-DOTA-IAM(OMe) platform renders it more attractive. Further modification of this latter core structure with carboxyamide arms featuring hydrophobic benzyl, hexyl, and trifluoro groups as well as hydrophilic amino acid based moieties generated a family of complexes that exhibit high cell viability (ED50 > 300 ?M) regardless of the lipophilicity or the overall complex charge. Only the hexyl-substituted complex reduced cell viability to 60% in the presence of 100 ?M complex. Additionally, cellular association was investigated by ICP-MS and fluorescence microscopy. Surprisingly, the hydrophobic moieties did not increase cell association in comparison to the hydrophilic amino acid derivatives. It is thus postulated that the hydrophilic nature of the 2-methoxyisophthalamide antenna (IAM(OMe)) disfavors the cellular association of these complexes. As such, responsive luminescent probes based on this scaffold would be appropriate for the detection of extracellular species. PMID:24901440

Peterson, Katie L; Dang, Jonathan V; Weitz, Evan A; Lewandowski, Cutler; Pierre, Valérie C

2014-06-16

448

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

449

STEM Colorado: Doppler Shift  

NSDL National Science Digital Library

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

Mccray, Richard; Koelemay, Andrew

2008-08-30

450

Synthesis and grafting of a BTP derivative onto a quartz crystal microbalance for lanthanide detection.  

PubMed

The ability of bis-triazinylpyridine (BTP) molecules to complex lanthanides is well-known in solution and can be judiciously utilized to elaborate solid sensing surfaces. This was done by synthesizing a new BTP derivative and covalently anchoring it onto gold surfaces. The BTP grafting, its chemical modification and the resultant lanthanide complexation were evaluated by combining X-ray Photoelectron Spectroscopy (XPS) and Polarization Modulation-Infrared Reflection Absorption Spectroscopy (PM-IRRAS). The detection of neodynium and europium cations was measured by a Quartz Crystal Microbalance (QCM). Interestingly, when immobilized on gold, BTP appeared to show very distinct sensitivities towards Eu(3+) and Nd(3+). Moreover, these sensitivities could be controlled by varying the pH and/or the nitrate concentration in solution. This novel strategy, consisting of the immobilization of BTP sensing molecules, is thus very promising for sensitive and specific lanthanide detection. PMID:20390153

Mercier, Dimitri; Leconte, Nicolas; Méthivier, Christophe; Suzenet, Franck; Guillaumet, Gérald; Wuillaume, Anne; Pradier, Claire-Marie

2010-06-21

451

An alternative fluorescence enhancement solution for use in lanthanide-based time-resolved fluoroimmunoassays.  

PubMed

Time-resolved fluoroimmunoassays that make use of lanthanide chelates as labels require the addition of an enhancement solution to elicit the formation of a fluorescent lanthanide complex. All solutions previously described are based on 2-naphthoyltrifluoroacetone (NTA), a beta-diketone. Currently, this compound is not commercially available. We report here the properties and performance of an enhancement solution prepared with a commercially available beta-diketone, thenoyltrifluoroacetone. Use of this solution in a commercial time-resolved fluoroimmunoassay gave results essentially identical to those obtained with the NTA-based solution, although fluorescence emission was approximately 27% lower. The lower fluorescence yield did not, however, significantly reduce assay sensitivity. We conclude that this solution represents a viable and highly economical alternative to the preparation currently in use, particularly for laboratories wishing to develop their own assays based on lanthanide fluorescence. PMID:3690848

Keelan, J A; France, J T; Barling, P M

1987-12-01

452

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

453

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

SciTech Connect

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

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

2013-07-01

454

Recent advances in development and application of derivatization reagents having a benzofurazan structure: a brief overview.  

PubMed

Chemical derivatization is often used to improve the separation efficiency and to enhance the detectability of the target compounds in high-performance liquid chromatography and capillary electrophoresis. The derivatization reagents having a benzofurazan (2,1,3-benzoxadiazole) structure are one of the most often used reagent for this purpose. In this paper, the recent advances in the development and the application of benzofurazan derivatization reagents are reviewed. PMID:24861741

Santa, Tomofumi

2014-06-01

455

Multi-modal imaging and cancer therapy using lanthanide oxide nanoparticles: current status and perspectives.  

PubMed

Biomedical imaging is an essential tool for diagnosis and therapy of diseases such as cancers. It is likely true that medicine has developed with biomedical imaging methods. Sensitivity and resolution of biomedical imaging methods can be improved with imaging agents. Furthermore, it will be ideal if imaging agents could be also used as therapeutic agents. Therefore, one dose can be used for both diagnosis and therapy of diseases (i.e., theragnosis). This will simplify medical treatment of diseases, and will be also a benefit to patients. Mixed (Ln1xLn2yO3, x + y = 2) or unmixed (Ln2O3) lanthanide (Ln) oxide nanoparticles (Ln = Eu, Gd, Dy, Tb, Ho, Er) are potential multi-modal imaging and cancer therapeutic agents. The lanthanides have a variety of magnetic and optical properties, useful for magnetic resonance imaging (MRI) and fluorescent imaging (FI), respectively. They also highly attenuate X-ray beam, useful for X-ray computed tomography (CT). In addition gadolinium-157 ((157)Gd) has the highest thermal neutron capture cross section among stable radionuclides, useful for gadolinium neutron capture therapy (GdNCT). Therefore, mixed or unmixed lanthanide oxide nanoparticles can be used for multi-modal imaging methods (i.e., MRI-FI, MRI-CT, CT-FI, and MRICT- FI) and cancer therapy (i.e., GdNCT). Since mixed or unmixed lanthanide oxide nanoparticles are single-phase and solid-state, they can be easily synthesized, and are compact and robust, which will be beneficial to biomedical applications. In this review physical properties of the lanthanides, synthesis, characterizations, multi-modal imagings, and cancer therapy of mixed and unmixed lanthanide oxide nanoparticles are discussed. PMID:25439587

Park, J Y; Chang, Y; Lee, G H

2015-01-01

456

Ion imprinted polymer particles for separation of yttrium from selected lanthanides.  

PubMed

Lanthanide(III) (Dy, Gd, Tb and Y) ion imprinted polymer (IIP) materials were synthesized via single pot reaction by mixing lanthanide imprint ion with 5,7-dichloroquinoline-8-ol, 4-vinylpyridine, styrene, divinylbenzene and 2,2'-azobisisobutyronitrile in 2-methoxyethanol porogen. The imprint ion was removed by stirring the above materials (after powdering) with 6 mol/L HCl to obtain the respective lanthanide IIP particles. Y-Dy, Y-Gd and Dy-Gd polymer particles were obtained by physically mixing equal amounts of the respective leached individual lanthanide(III) particles. Control polymer (CP) particles were similarly prepared without imprint ion. Application of the above synthesized polymer particles was tested for separation of Y from Dy, Gd and Tb employing batch and column SPE methods using inductively coupled plasma atomic emission spectrometry for the determination. Optimization studies show that Y present in 500 mL can be preconcentrated using Dy-Gd IIP particles and eluted with 20 mL of 1.0 mol/L of HCl, providing an enrichment factor of approximately 25. Dy-Gd IIP particles offer higher selectivity coefficients for Y over other lanthanides compared to other IIP particles and commercial liquid-liquid extractants. Selectivity studies for Y over other coexisting inorganic species (other than lanthanides) were also conducted and the results obtained show a quantitative separation of Y from other inorganics other than Cu(II) and Fe(III). Furthermore, both batch and column studies indicate the purification of yttrium concentrate from 55.0 +/- 0.2 to 65.2 +/- 0.2% in a single stage of operation. PMID:16833087

Kala, Ramakrishnan; Rao, Talasila Prasada

2006-06-01

457

Method for extracting lanthanides and actinides from acid solutions by modification of Purex solvent  

DOEpatents

A process has been developed for the extraction of multivalent lanthanide and actinide values from acidic waste solutions, and for the separation of these values from fission product and other values, which utilizes a new series of neutral bi-functional extractants, the alkyl(phenyl)-N, N-dialkylcarbamoylmethylphosphine oxides, in combination with a phase modifier to form an extraction solution. The addition of the extractant to the Purex process extractant, tri-n-butylphosphate in normal paraffin hydrocarbon diluent, will permit the extraction of multivalent lanthanide and actinide values from 0.1 to 12.0 molar acid solutions.

Horwitz, E.P.; Kalina, D.G.

1984-05-21

458

Lanthanide 4f-level location in AVO(4):Ln(3+) (A = La, Gd, Lu) crystals.  

PubMed

The spectral properties of LaVO(4), GdVO(4) and LuVO(4) crystals doped with Ce(3+), Pr(3+), Eu(3+) or Tb(3+) have been investigated in order to determine the position of the energy levels relative to the valence and conduction bands of the hosts along the trivalent and divalent lanthanide series. Pr(3+) and Tb(3+) ground state levels are positioned based on the electron transfer energy from those states to the conduction band, the so-called intervalence charge transfer (IVCT). This approach is compared with an alternative model that is based on electron transfer from the valence band to a lanthanide. PMID:21693921

Krumpel, Andreas H; van der Kolk, Erik; Cavalli, Enrico; Boutinaud, Philippe; Bettinelli, Marco; Dorenbos, Pieter

2009-03-18

459

Selectivity Sequence of Multivalent Lanthanides for Their Separation on Antimonate Based Exchangers  

Microsoft Academic Search

The adsorption of trivalent lanthanide ions, Ln (La, Pr, Nd, Gd, and Er), using two antimonate based exchangers, namely, silicon antimonate (SiSb) and poly(acrylamide titanium antimonate), PAmTA, was studied from their nitrate solutions at pH 3.5 ± 0.1. The formation constants in Ln\\/SiSb and Ln\\/PAmTA systems, logKS1 and logKS2, were calculated for the above mentioned lanthanides. The Kd values of the selected

G. M. Ibrahim; M. I. Ahmad; B. El-Gammal; I. M. El-Naggar

2011-01-01

460

Multiplex detection of enzymatic activity with responsive lanthanide-based luminescent probes.  

PubMed

Multiplex analyte detection in complex dynamic systems is desirable for the investigation of cellular communication networks as well as in medical diagnostics. A family of lanthanide-based responsive luminescent probes for multiplex detection is reported. The high modularity of the probe design enabled the rapid assembly of both green and red emitters for a large variety of analytes by the simple exchange of the lanthanide or an analyte-cleavable caging group, respectively. The real-time three-color detection of up to three analytes was demonstrated, thus setting the stage for the non-invasive investigation of interconnected biological processes. PMID:25504579

Pershagen, Elias; Borbas, K Eszter

2015-02-01

461

The susceptibility of bacteria to photodynamic inactivation with lanthanide complexes of chlorin e6  

NASA Astrophysics Data System (ADS)

Photodynamic inactivation (PDI) may be a very promising alternative method for antimicrobial treatment of many localised infections. In the present study we report the activity of three lanthanides (Eu(III), Pr(III), Yb(III)) complexes of Fotolon sensitizer, composed of chlorin e6 and polyvinylpyrrolidone (PVP), against standard E.coli P. aeruginosa, K. pneumoniae and S. aureus ATCC strains. The 160+/-10mW/cm2 of 651 nm laser light was applied for 600 seconds after photosensitiser administration (50?g/ml) and 30 minutes incubation time. Impact of pure Fotolon and pure lanthanides solution was examined as control groups.

Bednarkiewicz, Artur; Drulis-Kawa, Zuzanna; Wiglusz, Rafal; Legendziewicz, Janina; Bugla-Ploskonska, Gabriela; Doroszkiewicz, Wlodzimierz; Haupt, Manfred; Strek, Wieslaw

2005-08-01

462

Referenceless PRF shift thermometry.  

PubMed

The proton resonance frequency (PRF) shift provides a means of measuring temperature changes during minimally invasive thermotherapy. However, conventional PRF thermometry relies on the subtraction of baseline images, which makes it sensitive to tissue motion and frequency drift during the course of treatment. In this study, a new method is presented that eliminates these problems by estimating the background phase from each acquired image phase. In this referenceless method, a polynomial is fit to the background phase outside the heated region in a weighted least-squares fit. Extrapolation of the polynomial to the heated region serves as the background phase estimate, which is then subtracted from the actual phase. The referenceless method is demonstrated on a phantom during laser heating, 0 degrees temperature rise images of in vivo human liver, interstitial laser ablation of porcine liver, and transurethral ultrasound ablation of canine prostate. A good correlation between temperature maps reconstructed with the referenceless and subtraction methods was found. PMID:15170843

Rieke, Viola; Vigen, Karl K; Sommer, Graham; Daniel, Bruce L; Pauly, John M; Butts, Kim

2004-06-01

463

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

464

Phase shifting interferometer  

DOEpatents

An interferometer is disclosed which has the capability of measuring optical elements and systems with an accuracy of {lambda}/1000 where {lambda} is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about {lambda}/50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. Whereas current interferometers illuminate the optic to be tested with an aberrated wavefront which also limits the accuracy of the measurement, this interferometer uses an essentially perfect spherical measurement wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms. 11 figs.

Sommargren, G.E.

1999-08-03

465

Phase shifting interferometer  

DOEpatents

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

Sommargren, Gary E. (Santa Cruz, CA)

1999-01-01

466

Phase shifting diffraction interferometer  

DOEpatents

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

Sommargren, Gary E. (Santa Cruz, CA)

1996-01-01

467

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

468

Methods for generating phosphorylation site-specific immunological reagents  

DOEpatents

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

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

2001-01-01

469

Interactions of Plutonium and Lanthanides with Ordered Mesoporous Materials  

NASA Astrophysics Data System (ADS)

Ordered mesoporous materials are porous solids with a regular, patterned structure composed of pores between 2 and 50 nm wide. Such materials have attracted much attention in the past twenty years because the chemistry of their synthesis allows control of their unique physicochemical properties, which can be tuned for a variety of applications. Generally, ordered mesoporous materials have very high specific surface areas and pore volumes, and offer unique structures that are neither crystalline nor amorphous. The large tunable interface provided by ordered mesoporous solids may be advantageous in applications involving sequestration, separation, or detection of actinides and lanthanides in solution. However, the fundamental chemical interactions of actinides and lanthanides must be understood before applications can be implemented. This dissertation focuses primarily on the fundamental interactions of plutonium with organically modified mesoporous silica, as well as several different porous carbon materials, both untreated and chemically oxidized. A method for functionalizing mesoporous silica by self assembly and molecular grafting of functional organosilane ligands was optimized for the 2D-hexagonal ordered mesoporous silica known as SBA-15 (Santa Barbara amorphous silica). Four different organically-modified silica materials were synthesized and characterized with several techniques. To confirm that covalent bonds were formed between the silane anchor of the ligand and the silica substrate, functionalized silica samples were analyzed with 29Si nuclear magnetic resonance spectroscopy. Infrared spectroscopy was used in combination with 13C and 31P nuclear magnetic resonance spectroscopy to verify the molecular structures of the ligands after they were synthesized and grafted to the silica. The densities of the functional silane ligands on the silica surface were estimated using thermogravimetric analysis. Batch sorption experiments were conducted with solutions of Pu(IV), Pu(VI), Eu(III), Ce(III), and Zr(IV). The acetamide phosphonate functionalized silica called Ac-Phos-SBA-15 required more extensive synthesis than the other three functionalized silica materials. Development of functionalized mesoporous silica extractants for actinides is contingent on their synthesis and hydrolytic stability, and these two aspects of the Ac-Phos-SBA-15 material are discussed. This material showed the highest binding affinity for all of the target ions, and the sorption and desorption of Pu(VI) to Ac-Phos-SBA-15 was extensively investigated. Ordered mesoporous carbons are attractive as sorbents because of their extremely high surface areas and large pore volumes, and could be suitable substrates for the development of actinide sensors based on their electrochemical properties. Three different mesoporous carbon materials were synthesized by collaborators to test their application as radionuclide sorbent materials. The first is called CMK (carbons mesostructured by Korea Advanced Institute of Science and Technology), and was synthesized using a hard silica template with 3D-bicontinuous ordered mesostructure. Highly ordered body-centered cubic mesoporous carbon was synthesized by self-assembly of a phenol resin around a soft polymer template, and this material is known as FDU-16 (Fudan University). Etching of the silica portion of mesoporous carbon-silica composites created the 2D-hexagonal mesoporous carbon called C-CS (carbon from carbon-silica nanocomposites) with a bimodal pore size distribution. The as-synthesized nanocast mesoporous carbon in this work is called UN CMK, and the same material after oxidation treatment with nitric acid is called OX CMK. A portion of both FDU-16-type and C-CS-type ordered mesoporous carbons were oxidized with acidic ammonium persulfate, which created the oxidized carbon materials called FDU-16-COOH and C-CS-COOH, respectively. The mesoporous carbons were characterized by scanning electron microscopy to view their particle sizes and morphologies. Their porosities and structures on the meso-scale were an

Parsons-Moss, Tashi

470

Methodical aspects of blood coagulation measurements in birds applying commercial reagents--a pilot study.  

PubMed

The aim of this study was to examine the suitability of commercially available reagents for measurements of coagulation parameters in citrated plasma from birds. Therefore, plasma samples of 17 healthy donor birds of different species were used to determine prothrombin time (PT), activated partial thromboplastin time (aPTT) and thrombin time (TT) applying various commercial reagents which are routinely used in coagulation diagnostics in humans and mammals. A PT reagent based on human placental thromboplastin yielded not only shorter clotting times than a reagent containing recombinant human tissue factor (median 49 vs. 84 s), but also showed a minor range of distribution of values (43-55 s vs. 30-147 s, minimum-maximum, n = 5 turkeys). An aPTT reagent containing kaolin and phospholipids of animal origin delivered the shortest clotting times and the lowest range of variation in comparison to three other reagents of different composition. However, even when this reagent was used, aPTTs were partially extremely long (> 200 s). Thrombin time was 38 s (28-57 s, n = 5 chicken) when measured with bovine thrombin at a final concentration of 2 IU thrombin/ ml. Coefficients of variation for within-run precision analysis (20 repetitions) of PT was 8.0% and 4.7% for aPTT measurements using selected reagents of mammalian origin. In conclusion, of the commercially available reagents tested, a PT reagent based on human placental thromboplastin and an aPTT reagent including rabbit brain phospholipid and kaolin, show some promise for potential use in birds. PMID:25080826

Guddorf, Vanessa; Kummerfeld, Norbert; Mischke, Reinhard

2014-01-01

471

Colloidal metal nanoparticles: New building blocks for materials and amplification reagents for immunoassays  

NASA Astrophysics Data System (ADS)

This thesis describes new analytical uses for colloidal metal nanoparticles. Investigations into the ligand directed self-assembly of new materials from metal nanoparticles and applications of metal nanoparticle arrays in electrochemistry and immunosensing have addressed several issues; These include (i) the development of a stepwise method to assemble materials composed of metal nanoparticles entirely from solution, (ii) characterization of morphological, optical and electrical properties of these materials, and (iii) potential applications for nanoparticle materials such as biocompatible electrodes, microband electrodes, and patterned arrays. Also discussed are (iv) interactions of colloidal metal particle arrays with surface plasmons, and (v) a new motif for ultrasensitive detection of immunological binding events. A novel method of layer-by-layer film formation from solution of metal nanoparticles film generation was developed and investigated. Atomic force microscopy of multilayered structures revealed an underlying porous nanostructure and a lack of inter- and intra particle order. Optical properties and DC resistance were monitored as a function of colloid coverage and bifunctional crosslinker. High coverage films were similar to evaporated discontinuous metal films in transmission properties (uv-vis/NIR) and in appearance by eye these films resembled their bulk metal counterparts. The measured resistivity was only 100 times greater than bulk Au. Applications in electrochemistry and the construction of a microband electrode of nanometer dimensions, is discussed and detailed further in chapter 4. Chapter 5 encompasses probing nanoparticle assemblies with surface plasmon resonance and the applications of colloidal Au nanoparticles as signal amplification reagents in a sandwich immunoassay. The binding of anti-human IgG:Au colloid conjugate to human IgG immobilized on an Au film produced a enhanced shift in plasmon angle over unconjugated antibody. Detection limits were decreased 25-fold in the amplified geometry. Controls were tested against common biological interferences and a correlation between particle surface coverage and plasmon resonance shift was investigated. Applications of the methodology to nonidealized samples were successful. Finally, chapter 6 explores the challenge of transferring colloid amplification methodology to a commercial SPR instrument and a new method of amplification within a dextran extended coupling matrix by electroless Ag deposition onto 1.8-nm diameter protein conjugates. As in chapter 5 reflectance shifts due to antibody colloid conjugate are correlated to particle coverage and analyte concentration.

Musick, Michael David

472

Theoretical, spectral characterization and antineoplastic activity of new lanthanide complexes.  

PubMed

The new cerium(III), lanthanum(III) and neodymium(III) complexes were synthesized in view of their application as cytotoxic agents. The complexes were characterized by different physicochemical methods: elemental analysis, mass spectrometry, (1)H NMR, (13)C NMR and IR spectroscopy. The spectra of the complexes were interpreted on the basis of comparison with the spectrum of the free ligand. The vibrational analysis showed that in the complexes the ligand coordinates to the metal ion through both deprotonated hydroxyl groups, however participation of the carbonyl groups in the coordination to the metal ion was also suggested. Geometry optimization of 3,3'-(ortho-pyridinomethylene)di-[4-hydroxycoumarin] H(2)(o-pyhc), (H(2)L) and its dianionic forms, o-pyhc(2-), (L(2-)) were carried out at AM1 and PM3 levels as well as using density functional theory with Becke's three parameter hybrid method and correlation functional of Lee, Yang and Parr (B3LYP) with 6-31G(d) basis set. The optimized geometries of the neutral ligand isomers were stabilized by two asymmetrical intramolecular O-H...O hydrogen bonds (HBs). The conformational search showed four low-energy dianionic species (o-pyhc(2-)) on the potential energy surface. Molecular electrostatic potential calculations showed that the most preferred sites for electrophilic attack in H(2)(o-pyhc) and o-pyhc(2-) are the carbonyl oxygen atoms. The evaluation of the cytotoxic activity of the novel lantanide complexes on HL-60 myeloid cells revealed, that they are potent cytotoxic agents. The cerium complex was found to exhibit superior activity in comparison to the lanthanum, and neodymium species, the latter being the least active. Taken together our data give us a reason to conclude that the newly synthesized lanthanide complexes should be a subset to further more detailed pharmacological and toxicological evaluation. PMID:18565422

Kostova, Irena; Trendafilova, Natasha; Momekov, Georgi

2008-01-01

473

First examples of ternary lanthanide 5-aminoisophthalate complexes: Hydrothermal syntheses and structures of lanthanide coordination polymers with 5-aminoisophthalate and oxalate  

NASA Astrophysics Data System (ADS)

Two new lanthanide coordination polymers with mixed-carboxylates, [Ln(OX)(HAPA)(H 2O)] n[Ln = Eu ( 1), Ho ( 2); H 2APA = 5-aminoisophthalic acid; OX = oxalate] were obtained by hydrothermal reactions, and characterized by single crystal X-ray diffraction, elemental analysis and IR spectra. Complexes 1 and 2 are both 3-D supramolecular structure, in which lanthanide ions are bridged by oxalate and 5-aminoisophthalate ligands forming 2-D metal-organic framework, and 2-D networks are further architectured to form 3-D supramolecular structures by hydrogen bonds. The two carboxylate groups of H 2APA ligand are all deprotonated and exhibit chelating and bridging bidentate coordination modes, respectively, and the amino group in HAPA presents - NH3+ in the titled complexes. The thermogravimetric analysis was carried out to examine the thermal stability of the titled complexes. And the photoluminescence property of 1 was investigated.

Liu, Chong-Bo; Wen, Hui-Liang; Tan, Sheng-Shui; Yi, Xiu-Guang

2008-05-01

474

Water-soluble organophosphorus reagents for mineralization of heavy metals.  

SciTech Connect

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

Nash, K. L.

1999-02-26

475

Hydrogenation of Single-Wall Carbon Nanotubes Using Polyamine Reagents: Combined Experimental and  

E-print Network

oxidation of SWNTs using some combination of sulfuric acid, nitric acid, and occasionally hydrogen peroxide9Hydrogenation of Single-Wall Carbon Nanotubes Using Polyamine Reagents: Combined Experimental hydrogenation of single-wall carbon nanotubes using high boiling polyamines as hydrogenation reagents. Our

476

POLYNUCLEAR AROMATIC HYDROCARBON (PAH) RELEASE FROM SOIL DURING TREATMENT WITH FENTON'S REAGENT  

EPA Science Inventory

Fenton's Reagent was used to treat soil from a wood-treating site in southeastern Ohio which had been contaminated with creosote. Slurries, consisting of 10 µg of contaminated soil and 30 mL water were treated with 40 mL of Fenton's Reagent (1:1 of 30% H2O2 ...

477

ATP measurement in sheep rumen digesta using dimethyl sulfoxide as an extraction reagent  

E-print Network

ATP measurement in sheep rumen digesta using dimethyl sulfoxide as an extraction reagent Sylvie the rumen contents of sheep fed with three different diets : beet pulp, semi- purified and grass-hay. After commercial reagents, NRB (1) and Nucleoline (2). The studies were conducted on sheep fed three different

Boyer, Edmond

478

Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules  

PubMed Central

Summary A review of the synthesis of natural products and bioactive compounds adopting phosphonamide anion technology is presented highlighting the utility of phosphonamide reagents in stereocontrolled bond-forming reactions. Methodologies utilizing phosphonamide anions in asymmetric alkylations, Michael additions, olefinations, and cyclopropanations will be summarized, as well as an overview of the synthesis of the employed phosphonamide reagents. PMID:25246946

Focken, Thilo

2014-01-01

479

CLAY AND CLAY-SUPPORTED REAGENTS IN ORGANIC SYNTHESES: JOURNAL ARTICLE  

EPA Science Inventory

NRMRL-CIN-0866 Varma*, R.S. Clay and Clay-Supported Reagents in Organic Syntheses. Tetrahedron (Sir J.E. Baldwin (Ed.), Elsevier Science Ltd) 58 (7):1235-1255 (2002). EPA/600/J-02/032. 10/28/1999 CLAY AND CLAY-SUPPORTED REAGENTS HAVE BEEN USED EXTENSIVELY FOR SYNTHETIC ORGA...

480

Enantioselective Alkenylation via Nickel-Catalyzed Cross-Coupling with Organozirconium Reagents  

PubMed Central

A new family of organometallic compounds, organozirconium reagents, are shown to serve as suitable partners in cross-coupling reactions of (activated) secondary alkyl electrophiles. Thus, the first catalytic method for coupling secondary ?-bromoketones with alkenylmetal reagents has been developed, specifically a mild, versatile, and stereoconvergent carbon–carbon bond-forming process that generates potentially labile ?,?-unsaturated ketones with good enantioselectivity. PMID:20302338

Lou, Sha; Fu, Gregory C.

2010-01-01

481

Exploring the Potential for Using Inexpensive Natural Reagents Extracted from Plants to Teach Chemical Analysis  

ERIC Educational Resources Information Center

A number of scientific articles report on the use of natural extracts from plants as chemical reagents, where the main objective is to present the scientific applications of those natural plant extracts. The author suggests that natural reagents extracted from plants can be used as alternative low cost tools in teaching chemical analysis,…

Hartwell, Supaporn Kradtap

2012-01-01

482

Lanthanide based tuning of luminescence in MOFs and dense frameworks--from mono- and multimetal systems to sensors and films.  

PubMed

This feature article focuses on tuning options of photoluminescence properties of lanthanide containing Metal-Organic Frameworks (MOFs) and Dense Frameworks by selection of an appropriate set of metal ions together with suitable ligands. In addition to lanthanide-only systems, frameworks with main group and transition metal ions that are heterometallic or co-doped with variable lanthanide content offer excellent tuning options for luminescence. The MOF feature porosity enables further applications such as sensors for a large number of chemical analytes by selective influences on the luminescence upon contact. The application of functional thin films marks the most recent development of this amazingly growing field, involving processing and structuring. PMID:24816926

Meyer, L V; Schönfeld, F; Müller-Buschbaum, K

2014-08-01

483

Realgar as a building block for lanthanide clusters: encapsulation of a copper cluster by a lanthanide cluster.  

PubMed

The reactions of the divalent lanthanide metallocenes [Cp*2Ln(thf)2] (Cp* = ?(5)-C5Me5; Ln = Sm, Yb) with realgar (As4S4) gave the open cage tetrametallic complex [(Cp*2Sm)(Cp*Sm)3AsS3(Cp*AsS2)2(thf)3] (1) or the trimetallic cage compound [(Cp*Yb)3As2S4(Cp*AsS2)(thf)2] (2), respectively, by reductive cleavage of the inorganic cage. As result of a Cp* transfer, the novel Cp*AsS2(2-) anion is formed. Moreover, the As2S4(4-) anion, which is bound in 2, is observed for the first time in coordination chemistry. Closed cage compounds are formed by either using bulkier ligands or a different As/S cage. The reaction of [Cp?2Sm] (Cp? = (1,2,4-(t-Bu)3C5H2)) with As4S4 and the reaction of [Cp*2Yb(thf)2] with dimorphite (As4S3) gave the closed 11-vertex cage clusters [(Cp?Sm)3(AsS3)2] (3) and [(Cp*Yb)3(AsS3)2] (4), respectively. The reaction of 3 with [CuMes] resulted in the formation of the Sm/S/Cu cluster [(Cp?Sm(thf))4Cu4S6] (5), in which the Sm atoms encapsulate a classical Cu4S6(8-) cluster core. This is the first transition metal chalcogenide cluster encapsulated by f-elements. Alternatively, the endohedral cluster can thus be described as [Cu4@{(Cp?Sm(thf))4S6}], in which a Cu4 tetrahedron is encapsulated by the samarium sulfido cluster {(Cp?Sm(thf))4S6}. PMID:25247871

Arleth, Nicholas; Bestgen, Sebastian; Gamer, Michael T; Roesky, Peter W

2014-10-01

484

Electronic interaction anisotropy between open-shell lanthanide atoms and helium from cold collision experiment  

E-print Network

Electronic interaction anisotropy between open-shell lanthanide atoms and helium from cold and helium is extremely small. The interaction of the rare-earth atoms with He gives rise to several shells submerged under the filled 6s electronic orbitals, resulting in large electronic spin and orbital

Krems, Roman

485

Tetrametallic lanthanide(III) phosphonate cages: synthetic, structural and magnetic studies.  

PubMed

The synthesis, structures and magnetic properties of a family of lanthanide complexes containing phosphonate ligands are reported. Reaction of hydrated lanthanide nitrate and (t)butylphosphonic acid under reflux conditions in iso-butanol, in the presence of pivalic acid as a co-ligand produced five new lanthanide complexes; pyridine (py) was present as a base. The compounds formed are tetrametallic, with the general formula [pyH]4[Ln4(?3-OH)(O3P(t)Bu)3(HO3P(t)Bu)(O2C(t)Bu)2(NO3)6] where Ln = Gd(III), 1; Tb(III), 2; Dy(III), 3; Ho(III), 4 and Er(III), 5. The metal sites within the complexes lie on the vertices of a triangle-based pyramid, with phosphonate ligands on the triangular faces linking the apical Ln site to the Ln sites in the base. Each lanthanide(III) site is eight-coordinate. Magnetic studies of the compounds show a decline in the product ?(M)T with T; modelling the behaviour of 1 shows anti-ferromagnetic exchange between Gd(III) centres within the triangle with a negligible interaction to the fourth Gd(III) centre at the apex of the trigonal pyramid. PMID:25310820

Zangana, Karzan H; Pineda, Eufemio Moreno; Winpenny, Richard E P

2014-12-01

486

Preparation and time-resolved luminescence bioassay application of multicolor luminescent lanthanide nanoparticles.  

PubMed

Because highly luminescent lanthanide compounds are limited to Eu(3+) and Tb(3+) compounds with red (Eu, approximately 615 nm) and green (Tb, approximately 545 nm) emission colors, the development and application of time-resolved luminescence bioassay technique using lanthanide-based multicolor luminescent biolabels have rarely been investigated. In this work, a series of lanthanide complexes covalently bound silica nanoparticles with an excitation maximum wavelength at 335 nm and red, orange, yellow and green emission colors has been prepared by co-binding different molar ratios of luminescent Eu(3+)-Tb(3+) complexes with a ligand N,N,N(1),N(1)-(4'-phenyl-2,2':6',2''-terpyridine-6,6''-diyl)bis(methylenenitrilo) tetrakis (acetic acid) inside the silica nanoparticles. The nanoparticles characterized by transmission electron microscopy and luminescence spectroscopy methods were used for streptavidin labeling, and time-resolved fluoroimmunoassay (TR-FIA) of human prostate-specific antigen (PSA) as well as time-resolved luminescence imaging detection of an environmental pathogen, Giardia lamblia. The results demonstrated the utility of the new multicolor luminescent lanthanide nanoparticles for time-resolved luminescence bioassays. PMID:19851848

Jiang, Hongfei; Wang, Guilan; Zhang, Wenzhu; Liu, Xiaoyu; Ye, Zhiqiang; Jin, Dayong; Yuan, Jingli; Liu, Zhiguang

2010-01-01

487

Remarkable structural diversity and single-crystal-to-single-crystal transformations in sulfone functionalized lanthanide MOFs  

E-print Network

- rials for specific applications.5 However, while the currently extensive studies are focus on MOFs based novel sulfone functionalized Zn-based MOFs (UoC-1 and UoC-2) with unprecedented inorganic and organic functionalized lanthanide MOFs Eleftheria Neofotistou,a Christos D. Malliakasb and Pantelis N. Trikalitis

Trikalitis, Pantelis N.

488

Method of loading organic materials with group III plus lanthanide and actinide elements  

DOEpatents

Disclosed is a composition of matter comprising a tributyl phosphate complex of a group 3, lanthanide, actinide, or group 13 salt in an organic carrier and a method of making the complex. These materials are suitable for use in solid or liquid organic scintillators, as in x-ray absorption standards, x-ray fluorescence standards, and neutron detector calibration standards.

Bell, Zane W. (Oak Ridge, TN); Huei-Ho, Chuen (Oak Ridge, TN); Brown, Gilbert M. (Knoxville, TN); Hurlbut, Charles (Sweetwater, TX)

2003-04-08

489

Determining binding energies of valence-band electrons in insulators and semiconductors via lanthanide spectroscopy  

NASA Astrophysics Data System (ADS)

Models and methods to determine the absolute binding energy of 4f-shell electrons in lanthanide dopants will be combined with data on the energy of electron transfer from the valence band to a lanthanide dopant. This work will show that it provides a powerful tool to determine the absolute binding energy of valence band electrons throughout the entire family of insulator and semiconductor compounds. The tool will be applied to 28 fluoride, oxide, and nitride compounds providing the work function and electron affinity together with the location of the energy levels of all divalent and all trivalent lanthanide dopants with an accuracy that surpasses that of traditional methods like photoelectron spectroscopy. The 28 compounds were selected to demonstrate how work function and electron affinity change with composition and structure, and how electronic structure affects the optical properties of the lanthanide dopants. Data covering more than 1000 different halide (F, Cl, Br, I), chalcogenide (O, S, Se), and nitride compounds are available in the archival literature enabling us to routinely establish work function and electron affinity for this much wider collection of compounds.

Dorenbos, Pieter

2013-01-01

490

Hot-pressed silicon nitride with various lanthanide oxides as sintering additives  

NASA Technical Reports Server (NTRS)

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/ centimeters squared for 60 min. The crystallization of yttrium and lanthanide-silicon oxynitrides which was observed inn the sintered body containing yttrium-lanthanide mixed oxides as additives led to the formation of a highly refractory Si3N4 ceramic having a bending strength of 82 and 84 kg/millimeters squared at room temperature and 1300 C respectively. In a Y2O3+La2O3 system, a higher molar ratio of La2O3 to Y2O3 gave a higher hardness and strength at high temperatures. It was found that 90 min was an optimum sintering time for the highest strength.

Ueno, K.; Toibana, Y.

1984-01-01

491

Ln IONS AS LUMINESCENT PROBES OF PROTEINS 323 Lanthanide Ions as Luminescent Probes of  

E-print Network

have been employed, including enhancement or quenching of the lanthanide emission, energy transfer hybridization assays with applications that range from the determination of genetic and infectious diseases to providing accurate personal identification. Luminescence enhancement of a given probe in the presence

Turro, Claudia

492

Solid-liquid separation of oxidized americium from fission product lanthanides  

NASA Astrophysics Data System (ADS)

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 separation methods have been developed to address this difficult separation. Under acidic conditions using oxone or persulfate, the oxidation and retention of tracer Am in the aqueous phase has been observed with a separation factor of 11 ± 1. Most of these studies have been conducted using 237NpO2(NO3), 233UO2(NO3)2, 238Pu(NO3)4 and 241Am(NO3)3 at radiotracer concentrations. Lanthanides precipitate as the sodium or potassium europium double sulfate salt. Under basic conditions, ozone oxidation of Am(CO3)OH(s) solubilizes Am from a lanthanide carbonate hydroxide solid phase to the aqueous phase as the AmO2(CO3)34-or AmO2(CO3)35- species. For the ozone oxidation of the americium tracer a separation factor of 1.6 ± 0.8 and 47 ± 2 for the oxidation/separation in Na2CO3 and NaHCO3 respectively.

Shehee, T. C.; Martin, L. R.; Nash, K. L.

2010-03-01