bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production of235Np,236Pu and237Puvianuclear reactions on235,236,238U and237Np targets
Authors: Aaltonen J. , Dendooven P. , Gromova E. A. , Heselius S.-J. , Jakovlev V. A. , Trzaska W. H. 
Published: December 2003

SummaryA summary of methods for cyclotron production of235Np (396.1d),236Pu (2.858y) and237Pu (45.2d)vianuclear reactions with protons and3He-ions on235,236,238U and237Np targets in wide energy ranges is given. Methods for the chemical separation and purification of these nuclides from the irradiated uranium and neptunium targets are described. Cross sections, yields and radionuclidic purities of235Np,236Pu and237Pu are presented and compared with literature data on the nuclear reactions leading to these radionuclides. The nuclear reactions with the so far highest known yields of235Np,236Pu and237Pu are determined:236U(p,2n)235Np,237Np(p,2n+pnβ-)236Pu and237Np(p,n)237Pu, respectively. The highest radionuclidic purity of235Np,236Pu and237Pu tracers can be reached with the236U(p,2n)235Np,236U(p,nβ-)236Pu and237Np(3He,t)237Pu reactions, respectively. In addition new cross sections and yield data of the236U(3He,p3n)235Np reaction in the energy range 42.4–60 MeV are given.
Spectroscopic study (TRLFS and EXAFS) of the kinetics of An(III)/Ln(III) humate interaction
Authors: Monsallier Jean-Marc , Artinger Robert , Denecke Melissa A. , Scherbaum Franz J. , Buckau Gunnar , Kim Jae-Il 
Published: December 2003

SummaryHumic acid metal ion interaction shows a complex kinetic behavior. Dissociation kinetics reported in the literature reach from hours to basically irreversibility. Different suggestions for the responsible mechanisms have been made. One possibility is variations in the metal ion humate complex environment, subject to this study. The dissociation kinetics of Eu(III)/Tb(III)/Cm(III) humate complexes is investigated with purified humic acid solution (Gohy-573(HA), pH=6.0,I=0.1M (NaClO4)) and a humic rich groundwater (Gohy-532, pH=7.5). The different kinetic modes are verified by both scavenging of dissociated metal ions by an cation exchanger added after different metal ion humic acid contact times, and isotope exchange under stationary conditions,i.e.without change in metal ion humic acid ratio. The metal ion humate complex environment is studied by time resolved laser-induced laser fluorescence spectroscopy (TRLFS) and EXAFS. TRLFS shows that slower dissociating Cm(III) humate has a peak maximum at 600.5nm contrary to the fast dissociating ones with a peak maximum around 602.8nm. EXAFS also shows differences between slow and fast dissociating complexes (Tb(III), with an average Tb(III) oxygen distance of 2.37Å for an equilibrium mixture, and 2.33Å for only the slow dissociating complex. TRLFS shows that complexes with fast and slow dissociation kinetics have returned to the original distribution three days after removal of the fast dissociating metal ions and thus the different kinetic modes are in exchange equilibrium with each other. Furthermore, the isotope exchange investigations verify that humic acid europium flocculate basically behaves like dissolved/dispersed humate complexes.
Sorption and desorption of neptunium(V) on loess: batch and column experiments
Authors: Weijuan Li , Zuyi Tao , Liangtian Guo , Shushen Li 
Published: December 2003

SummaryThe sorption and desorption isotherms and the corresponding distribution coefficients (Kd, mL/g) of Np(V) for untreated loess and three kinds of treated loesses were determined by using the batch technique at moderate concentrations (∼10-5mol/L) under ambient aerobic conditions in the presence of 0.01mol/L CaCl2. For the treated loesses, selective extraction methods were used to remove CaCO3and organic matter (OM) from the loess. The isotherms were analyzed with the Freundlich equation. The relative contributions of OM and CaCO3to the Np(V) sorption on the loess were investigated from the parameters of the Freundlich equation. The effects of adding fulvic acid (FA) from the loess and the carbonate in solution on the sorption of neptunium(V) on the loess were studied. The breakthrough curves (BTCs) and displacement curves (DPCs) of Np(V) on the untreated loess column and on the treated loess columns were determined under ambient aerobic conditions at moderate concentration (1.1×10-4mol/L) in the presence of 0.01mol/L CaCl2. The results of column experiments are in accord with the results of batch experiments. It was found that (1) Np(V) in the loess under the present experimental conditions was relatively mobile and the distribution coefficients were relatively low at moderate concentrations, (2) the sorption/desorption hysteresis of Np(V) on the loess occurs, (3) the sorption of Np(V) on the loess was mainly determined by the clay minerals, (4) the addition of FA or carbonate in the aqueous solutions had an obvious positive effect on the Np(V) sorption on the loess, (5) the retardation of Np(V) migration in the loess at moderate concentrations was inconsiderable.
Characterization of U(VI)-Acidithiobacillus ferrooxidans complexes using EXAFS, transmission electron microscopy, and energy-dispersive X-ray analysis
Authors: Merroun Mohamed , Hennig C. , Rossberg A. , Reich T. , Selenska-Pobell S. 
Published: December 2003

Summary
We used a combination of Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy, Transmission Electron Microscopy (TEM) and Energy-Dispersive X-ray (EDX) analysis to conduct molecular scale studies on U(VI) interaction with three recently described eco-types of Acidithiobacillus ferrooxidans. On the basis of the information obtained by using these methods, we concluded that uranyl phosphate complexes were formed by the cells of the three eco-types studied. The uranium accumulated by A. ferrooxidans cells was located mainly within the extracellular polysaccharides, and on the cell wall. Smaller amounts were also observed in the cytoplasm.
Synergistic extraction of uranium(VI) by 2-hydroxy-1-naphthaldehyde thiosemicarbazone and several neutral donors
Authors: Banerjee S. , Bhar M. , Basu S. 
Published: December 2003

Summary
The extraction behaviour of U (VI) from an aqueous nitric acid medium employing a 2-hydroxy-1-naphthaldehyde thiosemicarbazone in ethyl acetate has been studied in presence of different neutral donors like trioctyl phosphine oxide (TOPO), dimethyl sulphoxide (DMSO) and trioctyl amine (TOA). The extraction constant (log k
ex) for the binary organic phases UO2·A·X (where A=ligand, X=NO3
-1) was found to be 1.976 which is by far the largest value amongst known values for the thiosemicarbazone. The overall equilibrium constant (log K) for the ternary complexes UO2A(NO3)·TOPO, UO2A(NO3)·TOA and UO2A(NO3)·DMSO were estimated to be 6.06, 6.77 and 4.95, respectively. The effect of different diluents on the extraction behaviour has also been studied.
Complex formation of Tb3+with glycolate,D-gluconate andα-isosaccharinate in neutral aqueous perchlorate solutions
Authors: Zhernosekov K. P. , Mauerhofer E. , Getahun G. , Warwick Peter , Rösch Frank 
Published: December 2003

SummaryAn electromigration technique was used for measurements of metal-ligand formation constants of non-carrier-free160Tb3+with glycolate,D-gluconate andα-isosaccharinate ligands. The overall ion mobilities of Tb at different concentrations of the ligands were measured in chemically inert perchlorate solutions (pH 7 andT= 298.1K) with an overall ionic strengthμ= 0.1. The stepwise stoichiometric stability constants are: Tb3+/glycolate: logK1=2.72(18), logK2=1.73(19), logK3= 1.12(17), Tb3+/D-gluconate: logK1=2.96(11), logK2=2.60(11), logK3=1.13(9), Tb3+/α-ISA: logK1=3.07(8), logK2= 2.69(11), logK3= 1.80(12).
Sorption kinetics of cesium on hydrous titanium dioxide
Authors: Altaş Y. , Tel H. , Yaprak G. 
Published: December 2003

Summary
Two types of hydrous titanium dioxide possessing different surface properties were prepared and characterized to study the sorption kinetics of cesium. The effect of pH on the adsorption capacity were determined in both type sorbents and the maximum adsorption percentage of cesium were observed at pH 12. To elucidate the kinetics of ion-exchange reaction on hydrous titanium dioxide, the isotopic exchange rates of cesium ions between hydrous titanium dioxides and aqueous solutions were measured radiochemically and compared with each other. The diffusion coefficients of Cs+ ion for Type1 and Type2 titanium dioxides at pH 12 were calculated as 2.79×10-11m2s-1 and 1.52×10-11m2s-1, respectively, under particle diffusion controlled conditions.
Complexation of 188Re-phosphonates: in vitro and in vivo studies
Authors: Faintuch B. L. , Faintuch S. , Muramoto E. 
Published: December 2003

Summary
MDP (methylenediphosphonate) and HEDP (hydroxyethylidene diphosphonate), both diphosphonates, and EDTMP (ethylenediamine tetramethylene phosphonic acid), a tetraphosphonate ligand, have been previously labeled with 188Re for use in metastatic bone-pain palliation. The aim of this study was a comparison between the three complexes 188Re-MDP, 188Re-HEDP and 188Re-EDTMP concerning the complexation conditions, in order to achieve maximum yield, stability and bone uptake. Methods: MDP was dissolved in water and HEDP and EDTMP were dissolved in NaOH 1N followed by reduction of pH with HCl 1N. To all mixtures stannous chloride and 188Re4
- were added in a nitrogen atmosphere. The preparations were heated in boiling water bath for 15min. Yield as well as radiochemical stability was estimated by ITLC. Different concentrations of phosphonates and stannous chloride were evaluated. Biodistribution studies in Swiss mice were done for the three 188Re-phosphonates that presented the best radiochemical yield. The optimal ligand concentration for maximum complexation was 85.2mM for MDP, 72.8mM for HEDP and 45.8mM for EDTMP. The best amount of SnCl2·2H2O} was 1.5mg/mL for 188Re-HEDP and 1mg/mL for both 188Re-MDP and 188Re-EDTMP. In these conditons the three complexes showed a complexation rate above 95. Reasonable radiochemical stability for 24 hours was achieved by 188Re-EDTMP when employing ascorbic acid. All products showed a great uptake by the kidneys. 188Re-EDTMP had the greatest uptake by femur (3.1±0.2 ID/g) followed by 188Re-MDP (1.2±0.1 ID/g) and 188Re-HEDP (1.0±0.1 ID/g), 4 hours post injection. 188Re-EDTMP displayed a femur bone/muscle ratio of 28.5, 188Re-MDP 4.9 and 188Re-HEDP 4.9. In conclusion 188Re-EDTMP demonstrated the best potential as a radiopharmaceutical for bone cancer pain relief, encouraging further dosimetric studies and clinical trials.
Production and radioassay of Tc-94m for PET studies
Authors: Szajek Lawrence P. , Der M. , Divel J. , Huang B. X. , Plascjak P. , Eckelman W. C. 
Published: December 2003

Summary
The radionuclide Tc-94m with its positron branching ratio of 72, positron end-point energy of 2.47MeV, and relatively short half-life of 52 minutes is suitable for quantitative measurements using PET. Tc-94m can be produced by proton bombardment of isotopically enriched [Mo-94]MoO3. We prepare Tc-94m as pertechnetate in saline solution using a wet-chemical separation procedure employing a semi-automated apparatus. Tc-94m sestamibi and other radiopharmaceuticals are routinely produced from this reagent.
Speciation in solution: interaction between calixarene derivatives and lanthanides(III)
Authors: Arnaud-Neu Françoise 
Published: December 2003

Abstract
The importance of stability constant determination for the calculation of speciation diagrams is illustrated through several examples pertaining to the coordination chemistry in solution of trivalent lanthanides with chemically modified calixarene derivatives substituted either at the wide or the narrow rim by carboxylic acid, glycine or CMPO moieties. The influence of the analytical composition of the systems investigated is particularly analyzed.
Structure solution with PATSEE
Authors: Wagner K. , Hirschler J. , Egert E. 
Published: December 2003

Abstract
Patterson search is a powerful tool for solving difficult crystal structures since it actively uses chemical information. Our program PATSEE, which attempts to combine the merits of Patterson and direct methods in order to locate a fragment with known geometry in the unit cell, has solved a large number of crystal structures during the last decade and proved to be reliable and widely applicable. We have tested PATSEE successfully on 20 structures of different size and complexity contained in a test data bank using fragments either taken from related crystal structures or calculated by force-field methods. Even structures with several torsional degrees of freedom (like those of oligopeptides) could be solved convincingly. As a result, general experiences – such as requirements for the minimum size and the accuracy of a search fragment, the reliability of the various figures of merit, the chances to locate single atoms and to tackle larger structures – were gained, which should help in finding an optimum strategy for the solution of problem structures with PATSEE.
The quasicrystal-to-crystal transformation. II. Landau theory
Authors: Beraha L. , Steurer Walter , Perez-Mato J. M. 
Published: December 2003

Abstract
A phenomenological description of the quasicrystal-to-crystal transformation is presented in terms of Landau theory. The basic idea is to describe the structures of quasicrystals as incommensurately modulated structures and to use the tools developed for phase transitions of this kind. The usefulness of this description is demonstrated on quasiperiodic model structures: the one-dimensional (1D) Fibonacci sequence and the 2D Penrose tiling. The transformation to periodic structures is discussed generally for rational approximants.
Superstructure of strontium chromate aluminate sodalite at low temperatures
Authors: Többens D. M. , Depmeier W. 
Published: December 2003

Abstract
At high temperatures yellow strontium chromate aluminate sodalite Sr8[Al12O24](CrO4)2 has cubic symmetry with orientational disorder of the CrO4
2--ions within the sodalite cages. The existence of two phase transitions at 299K and 289K, which result in superstructures of tetragonal and orthorhombic symmetry, respectively, is well known. In this work we describe the crystal structure of the orthorhombic low temperature phase which was determined from neutron and x-ray powder diffraction. Additional information from 27Al-MAS-NMR spectra and the Monte-Carlo-method was used to get a starting model for the structure refinement. In the orthorhombic phase the CrO4-tetrahedra are fully ordered. Two thirds of the rings of four AlO4-tetrahedra forming the sodalite framework are nearly undistorted. The remaining, distorted, rings form chains parallel to the a-axis. The distortion of the rings is of a type which occurs in other aluminate sodalite structures as well and is known as the shearing mechanism. Despite of the different symmetry the structure of this phase is similar to the structure of strontium tungstate aluminate sodalite. The characteristic differences can be explained by the smaller size of the CrO4-tetrahedra.
The structure of the palladium-rich boride Pd5B (Pd16B3)
Authors: Ellner M. , Beck M. , Mittemeijer E. J. 
Published: December 2003

Abstract
The low-temperature boride Pd5B (Pd16B3) formscongruently from the corresponding interstitial solid solu-tion Pd(B) (Pearson-Parthé symbol cF(8-x), space group Fm3̅m) at 658 K. The structure of Pd5B has been investigated by X-ray powder diffraction yielding the following structural data: I4/mmm, tI2.38; unit cell parameters a = 0.28490(4) nm, c = 0.40038(9) nm, c/a = 1.405 < √2, with the occupation 2Pd (a) and 0.19 x 2B (b). The crystal chemical data of Pd5B and some other homeotypic interstitial compounds of transition metals have been compared.
Crystal structure and twinning of Bi4O5Br2
Authors: Keller E. , Ketterer J. , Krämer V. 
Published: December 2003

AbstractThe monoclinic crystal structure of Bi4O5Br2has been determined from 1:1 twinned crystals pretending orthorhombic symmetry. Bi4O5Br2crystallizes with space groupP21(no. 4),Z=4,a=14.539(4),b=5.605(1),c=10.782(3) Å,β= 97.75(7)°. Its structure shows much closer relationships to the structure ofα-Bi5O7I than to that one of the homologuous compound Bi4O5Cl2.
Synthesis and properties of 6-fluoro-7-chloro-4-oxo-4H-chromene 3-carboxylic acid. X-ray structure of achiral heterotopic 3-diethoxymethyl-6-fluoro-7-chloro-4-oxo-4H-chromene
Authors: Barili P. L. , Valenti P. , Artali R. , Bombieri G. , Da Re P. 
Published: December 2003

Abstract
Synthesis and reactions of 6-chloro-7-fluoro-4-oxo-4H-chromene-3-carboxylic acid are described. The molecular structure of its achiral heterotopic 3-diethoxy-methyl precursor has been determined by NMR spectroscopy and X-ray crystallography. C14H14ClFO4 is monoclinic, space group P21/a, with unit cell dimensions a = 14.923(5), b = 6.615(2), c = 14.921(5) Å, β = 101.44(3)°, V = 1443.7(8) Å3, Z = 4, D
calc. = 1.383 g/cm3.
Thermal expansion of decagonal Al70.7Co13.3Ni16.0 in the temperature range 15–300 K
Authors: Kupsch A. , Meyer D. C. , Gille P. , Paufler P. 
Published: December 2003

Abstract
The temperature dependence of lattice parameters a in the quasiperiodic plane and c in the periodic direction of decagonal Al70.7Co13.3Ni16.0 was probed using X-ray powder diffraction in the temperature range 15–300 K. Both parameters were fitted by means of positions of 22 Bragg reflections for each temperature. Temperature dependences were modelled best by second order polynomials leading to linear thermal coefficients α(T) = 8.1(33) · 10–7K–1 + 3.9(2)· 10–8K–2
T in the quasiperiodic plane and γ(T) = 1.7(6) · 10–6K–1 + 3.8(3) · 10–8K–2
T in the periodic direction, respectively. Thus we found the anisotropy ratio γ(T)/α(T) to decrease with increasing temperature from 1.10 (at 15 K) to 1.19 (at 300 K). Besides pecularities around 150 K indicating an intermediate phase formed by superordering, we observed deviations from the general smooth course between 15K and 50K for both lattice parameters.
The intermediate phase of strontium chromate aluminate sodalite
Authors: Többens D. M. , Depmeier W. 
Published: December 2003

Abstract
At high temperatures yellow strontium chromate aluminate sodalite Sr8[Al12O24](CrO4)2 has cubic symmetry with orientational disorder of the CrO4
2--ions within the sodalite cages. The existence of two phase transitions at 299 K and 289 K, which result in superstructures of tetragonal and orthorhombic symmetry, respectively, is well known. The structure of the orthorhombic low-temperature phase has been solved recently. In this work we discuss the crystal structure of the intermediate phase and its determination from neutron and x-ray powder diffraction data. The structure of this phase shows only very small distortions of the framework of AlO4-tetrahedra. The CrO4-tetrahedra within the sodalite cages are partially ordered. The observed distribution of their orientations can be described as a combination of those of the low- and the high-temperature phase. 27Al-MAS-NMR spectra reveal the dynamic nature of the structure.
Crystal structure and elastic properties of betaine fumarate and of betaine maleate, two isomers of ((CH3)3NCH2COOH . OOC(CH)2COOH
Authors: Haussühl E. , Schreuer J. 
Published: December 2003

Abstract
X-ray structure analyses of orthorhombic betaine fumarate and monoclinic betaine maleate yielded space group Pnma, a
1=26.510(5) Å, a
2=6.684(1)Å, a
3=6.376(1)Å, Z=4, ρ
calc=1.371g cm-3, ρ
obs=1.370 g cm-3 and, respectively, space group P21/n, a
1=6.132(1)Å, a
2=10.823(2)Å, a
3=17.246(3)Å, α
2=92.87(3)°, Z=4, ρ
calc=1.355 g cm-3, ρ
obs=1.351 g cm-3. In both compounds the hydrogen betaine cations are joined to the corresponding anions by strong H-bonds with O···O distances of about 2.48Å. Large single crystals of optical quality of betaine maleate have been grown from aqueous solutions. Further, we determined their coefficients of thermal expansion and their elastic and thermoelastic constants. In comparison to the pronounced anisotropy of the mechanical properties of betaine fumarate, the elastic constants of betaine, maleate appear only slightly anisotropic. Between 80 K and 305 K no phase transision could be detected in betaine maleate. However, softening of certain acoustic modes at temperatures below about 160 K might be a hint at structural instabilities at even lower temperatures.
Synthesis, electronic and crystal structure of a new organic semiconductor tetramethyltetrathiafulvalene-trinitroresorcinol (2:1), (TMTTF)2(C6H2N3O8)
Authors: Abashev G. G. , Gritsenko V. V. , Kazheva O. N. , Tenishev A. G. , Canadell E. , Dyachenko O. A. 
Published: December 2003

Abstract
A new organic semiconductor with trinitroresor-cinol as the anion, (TMTTF)2(C6H2N3O8) (1) (TMTTF: tetramethyltetrathiafulvalene),
has been synthesized and its crystal structure has been investigated at room and low temperatures (295 and 110 K). The crystal structure of 1 is formed by one-dimensional stacks of cation-radicals (TMTTF)+1/2 separated by trinitroresorcinol anions (C6H2N3O8)–. This novel salt reveals semiconducting properties. Tight-binding band structure calculations for 1 have been carried out in order to understand the charge distribution among the different donors.
Synthesis and crystal structure determination of 6-phenyl-5-phenylsulfonyl-1,2,3,4-tetrahydropyrimidine-2-thione from neutron powder diffraction data
Authors: Rybakov V. , Chernyshev V. V. , Tafeenko V. A. , Shutalev A. D. , Kurbakov A. I. , Trounov V. A. 
Published: December 2003

Abstract
The title compound was synthesized by reaction of N-(azidomethyl)thiourea or N-(tosylmethyl)thiourea with α-phenylsulfonylacetophenone in the presence of sodium hydride followed by p-toluenesulfonic acid treatment of the obtained N-[3-oxo-3-phenyl-2-(phenylsulfonyl)propyl]thiourea. The molecular and crystal structure of 6-phenyl-5-phenylsulfonyl-1,2,3,4-tetrahydropyrimidine-2-thione (C14H13N2S2O2; space group P21/a; Z=4; a=17.396(1) Å, b=5.887(1) Å, c=15.665(2) Å, β=104.89(1)o) have been determined and refined from neutron (the neutron diffraction was very effective for describing of this system due to using of partial hydrogen-deuterium substitution) powder diffraction data using grid search and a Rietveld procedures. The crystal structure is formed by centrosymmetric hydrogen-bonded dimers along a axis.
A contribution to the crystal chemistry of DL-malates
Authors: Fleck Michel , Tillmanns E. , Bohatý L. 
Published: December 2003

Abstract
The crystal structures of twelve different DL-malates have been determined and refined from single-crystal X-ray diffraction data. In addition, powder diffrac-tion data were used for the refinement of the lattice pa-rameters. The title compounds are the neutral DL-malates Li2(C4H4O5)·2H2O (space group P21/c), Mn(C4H4O5)·3H2O (Pbca), Cd(C4H4O5)·3H2O (P21/n), Sr2(C4H4O5)2·5H2O (P1̅) and Ba(C4H4O5). 2H2O (P1̅) as well as the acid DL-malates RbH(C4H4O5) (Fdd2), CsH(C4H4O5)·H2O (P21/n), MgH2(C4H4O5)2·4H2O (C2/c), CaH2(C4H4O5)2·2H2O (C2/c), ZnH2(C4H5O5)2·4H2O (C2/c), LiH3(C4H4O5)2 (P1̅), CsH3(C4H4O5)2 (P1̅). A comparison of DL-malate structures and a scheme of structural characterization according to cation polyhedra connection is proposed.
Absorption correction for crystal-environment attachments from direction cosines
Authors: Katrusiak Andrzej 
Published: December 2003

Abstract
A simple procedure for deriving absorption corrections for crystal-environment diffractometer attachments of radial symmetry, like high-pressure cells, cryostats, furnaces or capillaries, from the direction cosines of the primary and diffracted beams is presented. This method is applicable irrespective of the diffractometer type, equally for point and area detectors.