bluuebunny/crossref_metadata_2025 huggingface dataset:
The insertion geometry of the posterolateral corner of the knee
Authors: Brinkman J.-M. , Schwering P. J. A. , Blankevoort L. , Koolos J. G. , Luites J. , Wymenga A. B.
Published: September 2005

We have quantitatively documented the insertion geometry of the main stabilising structures of the posterolateral corner of the knee in 34 human cadavers. The lateral collateral ligament inserted posterior (4.6 mm, sd 2) and proximal (1.3 mm, sd 3.6) to the lateral epicondyle of the femur and posterior (8.1 mm, sd 3.2) to the anterior point of the head of the fibula. On the femur, the popliteus tendon inserted distally (11 mm, sd 0.8) and either anterior or posterior (mean 0.84 mm anterior, sd 4) to the lateral collateral ligament. The popliteofibular ligament inserted distal (1.3 mm, sd 1.2) and anterior (0.5 mm, sd 2.0) to the tip of the styloid process of the fibula.

The ligaments had a consistent pattern of insertion and, despite the variation between specimens, the standard deviations were less than the typical size of drill hole used in reconstruction of the posterolateral corner. The data provided in this study can be used in the anatomical repair and reconstruction of this region of the knee.
Metal-specific differences in levels of DNA damage caused by synovial fluid recovered at revision arthroplasty
Authors: Davies A. P. , Sood A. , Lewis A. C. , Newson R. , Learmonth I. D. , Case C. P.
Published: September 2005

Previous research has shown an increase in chromosomal aberrations in patients with worn implants. The type of aberration depended on the type of metal alloy in the prosthesis. We have investigated the metal-specific difference in the level of DNA damage (DNA stand breaks and alkali labile sites) induced by culturing human fibroblasts in synovial fluid retrieved at revision arthroplasty.

All six samples from revision cobalt-chromium metal-on-metal and four of six samples from cobalt-chromium metal-on-polyethylene prostheses caused DNA damage. By contrast, none of six samples from revision stainless-steel metal-on-polyethylene prostheses caused significant damage. Samples of cobalt-chromium alloy left to corrode in phosphate-buffered saline also caused DNA damage and this depended on a synergistic effect between the cobalt and chromium ions.

Our results further emphasise that epidemiological studies of orthopaedic implants should take account of the type of metal alloy used.
Coonrad-Morrey total elbow arthroplasty for tumours of the distal humerus and elbow
Authors: Athwal G. S. , Chin P. Y. , Adams R. A. , Morrey B. F.
Published: September 2005

We reviewed 20 patients who had undergone a Coonrad-Morrey total elbow arthroplasty after resection of a primary or metastatic tumour from the elbow or distal humerus between 1980 and 2002. Eighteen patients underwent reconstruction for palliative treatment with restoration of function after intralesional surgery and two after excision of a primary bone tumour. The mean follow-up was 30 months (1 to 192).

Five patients (25%) were alive at the final follow-up; 14 (70%) had died of their disease and one of unrelated causes. Local control was achieved in 15 patients (75%). The mean Mayo Elbow Performance Score improved from 22 (5 to 45) to 75 points (55 to 95). Four reconstructions (20%) failed and required revision. Seven patients (35%) had early complications, the most frequent being nerve injury (25%). There were no infections or wound complications although 18 patients (90%) had radiotherapy, chemotherapy or both.

The Coonrad-Morrey total elbow arthroplasty provides good relief from pain and a good functional outcome after resection of tumours of the elbow. The rates of complications involving local recurrence of tumour (25%) and nerve injury (25%) are of concern.
Fatigue injuries of the femur
Authors: Niva M. H. , Kiuru M. J. , Haataja R. , Pihlajamäki H. K.
Published: September 2005

The purpose of this study was to describe the anatomical distribution and incidence of fatigue injuries of the femur in physically-active young adults, based upon MRI studies. During a period of 70 months, 1857 patients with exercise-induced pain in the femur underwent MRI of the pelvis, hips, femora, and/or knees.

Of these, 170 patients had a total of 185 fatigue injuries, giving an incidence of 199 per 100 000 person-years. Bilateral injuries occurred in 9% of patients. The three most common sites affected were the femoral neck (50%), the condylar area (24%) and the proximal shaft (18%). A fatigue reaction was seen in 57%, and a fracture line in 22%. There was a statistical correlation between the severity of the fatigue injury and the duration of pain (p = 0.001). The location of the pain was normally at the site of the fatigue injury. Fatigue injuries of the femur appear to be relatively common in physically-active patients.
Symptomatic ossification of the anterior longitudinal ligament with stenosis of the cervical spine
Authors: Mizuno J. , Nakagawa H. , Song J.
Published: September 2005

Seven men with a mean age of 63.9 years (59 to 67) developed dysphagia because of oesophageal compression with ossification of the anterior longitudinal ligament (OALL) and radiculomyelopathy due to associated stenosis of the cervical spine. The diagnosis of OALL was made by plain lateral radiography and classified into three types; segmental, continuous and mixed. Five patients had associated OALL in the thoracic and lumbar spine without ossification of the ligamentum flavum.

All underwent removal of the OALL and six had simultaneous decompression by removal of ossification of the posterior longitudinal ligament or a bony spur. All had improvement of their dysphagia. Because symptomatic OALL may be associated with spinal stenosis, precise neurological examination is critical. A simultaneous microsurgical operation for patients with OALL and spinal stenosis gives good results without serious complications.
High-Resolution DNA Melting Analysis for Simultaneous Mutation Scanning and Genotyping in Solution
Authors: Zhou Luming , Wang Lesi , Palais Robert , Pryor Robert , Wittwer Carl T
Published: September 2005

Background: High-resolution DNA melting analysis with saturation dyes for either mutation scanning of PCR products or genotyping with unlabeled probes has been reported. However, simultaneous PCR product scanning and probe genotyping in the same reaction has not been described.

Methods: Asymmetric PCR was performed in the presence of unlabeled oligonucleotide probes and a saturating fluorescent DNA dye. High-resolution melting curves for samples in either capillaries (0.3 °C/s) or microtiter format (0.1 °C/s) were generated in the same containers used for amplification. Melting curves of the factor V Leiden single-nucleotide polymorphism (SNP) and several mutations in exons 10 and 11 of the cystic fibrosis transconductance regulator gene were analyzed for both PCR product and probe melting transitions.

Results: Independent verification of genotype for simple SNPs was achieved by either PCR product or probe melting transitions. Two unlabeled probes in one reaction could genotype many sequence variants with simultaneous scanning of the entire PCR product. For example, analysis of both product and probe melting transitions genotyped ΔF508, ΔI507, Q493X, I506V, and F508C variants in exon 10 and G551D, G542X, and R553X variants in exon 11. Unbiased hierarchal clustering of the melting transitions identified the specific sequence variants.

Conclusions: When DNA melting is performed rapidly and observed at high resolution with saturating DNA dyes, it is possible to scan for mutations and genotype at the same time within a few minutes after amplification. The method is no more complex than PCR and may reduce the need for resequencing.
X-ray absorption fine structure spectroscopy of plutonium complexes with bacillus sphaericus
Authors: Panak Petra J. , Booth C. H. , Caulder D. L. , Bucher J. J. , Shuh D. K. , Nitsche Heino
Published: September 2005

Knowledge of the plutonium complexes formed with bacterial cells is critical for predicting the influence of microbial interactions on the migration behavior of actinides in the environment. This investigation describes the interaction of plutonium(VI) with cells of the aerobic soil bacteria, Bacillus sphaericus. The studies include the quantification of carboxylate and phosphate functional groups on the cell walls by potentiometric titration and the determination of the plutonium speciation by X-ray absorption fine structure (XAFS). Extended-XAFS (EXAFS) was used to determine the identity of the Pu(VI) interfacial complex with the bacteria, and the Pu(VI) was found primarily bound to phosphate groups on the cell surface. No carboxylate complexation was detected.
Ion-molecule reactions of Ru+ and Os+ with oxygen in a Penning trap
Authors: Rieth U. , Herlert A. , Kratz Jens Volker , Schweikhard L. , Vogel M. , Walther C.
Published: September 2005

Gas-phase ion chemistry in a Penning trap has been explored for future experiments on the chemical properties of the heaviest elements. The Mainz Cluster Trap, a Penning trap experiment devoted to metal cluster research, has served as a model apparatus for SHIPTRAP which is being installed behind the velocity filter SHIP (Separator for Heavy Ion reaction Products) at the Gesellschaft für Schwerionenforschung (GSI) at Darmstadt. The reactions of stored Ru+ and Os+ with oxygen have been studied and the reaction products MO+ and MO2
+ (M = Ru, Os) have been observed. The corresponding rate constants have been measured and the results are discussed with respect to future studies of similar ion-molecule reactions of the element 108 (hassium) in SHIPTRAP.
Inner-sphere, outer-sphere and ternary surface complexes: a TRLFS study of the sorption process of Eu(III) onto smectite and kaolinite
Authors: Stumpf Thorsten , Bauer A. , Coppin F. , Fanghänel Thomas , Kim Jae-Il
Published: September 2005

The surface sorption process of Eu(III) onto smectite and kaolinite was investigated by time-resolved laser fluorescence spectroscopy (TRLFS) in the trace concentration range. The experiments were performed in 0.025 M and 0.45 M NaClO4. The sorption process of Eu(III) onto smectite was obtained by TRLFS under atmospheric conditions and in absence of CO2. The pH was varied between 3.5 and 9 at a fixed metal ion concentration of 3.3 × 10−6mol/L Eu(III). At low pH (< 4) the metal ion keeps its complete hydration sphere indicating outer-sphere complexation. With increasing pH the formation of an inner-sphere Eu(III) surface complex was observed. The differences in the spectra and the fluorescence emission lifetimes of the surface sorbed Eu(III) in presence and absence of carbonate indicate the formation of ternary clay/Eu(III)/carbonate complexes. The different europium/clay surface complexes were characterized by their fluorescence emission spectra (5D0→7F1/5D0→7F2intensity ratio) and their fluorescence emission lifetime.
Rate effected adsorption profile of selenium-thiocyanate complex onto polyurethane foam
Authors: Saeed Muhammad M. , Hasany Syed Moosa , Ahmed Munir
Published: September 2005

The sorption of preheated selenium-thiocyanate complexes onto polyurethane (PUR) foam has been studied as a function of equilibration time (1–60 min), concentration of selenium (3.80 × 10−4 −4.39 × 10−3 M) and amount of PUR foam. Maximum sorption (> 98%) has been achieved from 0.5 M hydrochloric acid solution within 20 minutes using 7.25 mg/cm3 PUR foam in the presence of 3.75 × 10−2 M thiocyanate ions. The sorption data have been subjected to Langmuir, Freundlich and Dubinin-Radushkevich (D–R) isotherms. The Freundlich parameters 1/n = 0.25 ± 0.02 and of K
F = 1.7 ± 0.2 mmole g−1, Langmuir constants M = 0.23 ± 0.01 mmole g−1 and of b = 23 ± 2 dm3 mmole−1 and of D-R constants, C
m = 0.82 ± 0.04 mmole g−1, β = −0.0032 ± 0.0002 mole2 kJ−2 and of E = 12.5 ± 0.2 kJ mole−1 have been evaluated. The kinetic data have been subjected to Morris-Weber, Lagergren and Reichenberg equations and rate constants of intraparticle transport and first order have been computed. Thermodynamic parameters of enthalpy, entropy and Gibbs free energy suggest the endothermic and spontaneous adsorption of Se(IV)-SCN complex onto PUR foam at higher temperature. The influence of common anions and cations on the accumulation of selenium-thiocyanate onto PUR foam has been carried out. The possible sorption mechanism has also been discussed.
Measurement of fission neutron spectrum averaged cross sections of some threshold reactions on dysprosium: small-scale production of no-carrier-added153Gd in a nuclear reactor
Authors: Waheed S. , Zaidi Jamshed H. , Ahmad Shujaat , Saleem M.
Published: September 2005

Employing the activation technique in combination with radiochemical separations and high-resolution γ-ray spectroscopy fission neutron spectrum averaged cross sections were measured for several (n, 2n), (n,p) and (n, α) reactions on isotopes of dysprosium; our measurements constitute the first systematic studies. Of special interest was the investigation of the156Dy(n, α)153Gd reaction for the production of no-carrier-added153Gd in a nuclear reactor. Using 100% enriched156Dy target, 8633 KBq of153Gd per batch can be produced which is, however, not sufficient for medical application.
Partitioning of 127I and 129I in an unconfined glaciofluvial aquifer on the Canadian shield
Authors: Alvarado-Quiroz N. G. , Kotzer T. G. , Milton G. M. , Clark I. D. , Bottomley D.
Published: September 2005

At AECL – Chalk River Laboratories, Ontario, Canada solid, low-level radioactive wastes from industrial, academic and medical applications have been stored in trenches above unconsolidated sandy glacial tills and permeable very-fine to fine-grained sands overlying crystalline bedrock. The sandy aquifer system drains into a swamp comprised of approximately 3 m of sphagnum peat. A comprehensive field and analytical program, involving measurements of total iodine, 129I, tritium, 14C and 13C/12C ratios in groundwater and geologic materials (sands and peats), was initiated at this site to examine the partitioning of 127I and 129I amongst the various reservoirs in this system and the controlling factors.

The maximum iodine concentration and 129I inside the groundwater contaminant plume at the recharge and discharge sites were 67.0 ng/ml and ∼8.3 × 1011 atoms/liter, and 32.4 ng/ml and ∼2.9 × 1011 atoms/liter, respectively, with positive correlations between iodine, 14C (0.82), and tritium (0.87). Maximum total iodine concentrations for in-plume, recharge-site sands and discharge-site peats were 190.1 µg/kg and 14100 µg/kg, respectively. 129I analyses on these same samples showed concentrations of 2.3 × 107 and 6.4 × 109 atoms/g of soil, respectively.

K
D values (concentration on porous medium/concentration in co-existing water) calculated from the contaminant plume data for 127I and 129I were 1.3 and 1.6 l/kg, respectively, at the recharge site and 486 and 93 l/kg, respectively, at the discharge area, indicating that both stable and radio-iodine are preferentially sorbed to the organic rich, aquifer materials at the discharge sites. Incremental leach experiments on these same geologic materials have borne out these differences, with 127I being more strongly sorbed than 129I, probably as the result of kinetically controlled sorption mechanisms and the differing residence times of stable and radio-iodine in this hydrologic regime.
Thermodynamics of the U(VI)-Ca2+-Cl−-OH−-H2O system: Solubility product of becquerelite
Authors: Rai Dhanpat , Felmy Andrew R. , Hess Nancy J. , LeGore V. L. , McCready D. E.
Published: September 2005

The solubility of synthetic becquerelite (Ca(UO2)6O4(OH)6·8H2O) was determined in 0.02, 0.1, and 0.5 M CaCl2solutions and at pCH+values ranging from approximately 4 to 11. The presence of becquerelite in equilibrated samples was confirmed by a combination of techniques involving X-ray diffraction, total chemical composition, and analyses of solubility data. The solubility data were interpreted using Pitzer's aqueous thermodynamic model and the thermodynamic data for U(VI) species available in the literature. The log of the solubility product for becquerelite [Ca(UO2)6O4(OH)6·8H2O + 14H+⇌ Ca2++ 6UO22++ 18H2O] was determined to be 41.4 ± 0.2. This value is similar to the values previously reported for other synthetic becquerelites, but is drastically different from a value reported for a natural sample.
Coprecipitation of thorium with UO2
Authors: Rousseau G. , Fattahi Massoud , Grambow Bernd , Boucher F. , Ouvrard G.
Published: September 2005

Coprecipitation may be a significant process in controlling radionuclide (RN) release during spent fuel dissolution/reprecipitation in a breached geological disposal site by water. The objective of this work was to study the coprecipitation of thorium with UO2 as host phase under reducing conditions (pure N2 and E
h<-100 mV/SHE) as a function of pH and [Th]/[U] initial concentration ratio. For pH < 4, the final concentration of Th was found to be considerably lower than expected if pure phase, Th(OH)4(s) was formed. Coprecipitation phenomena and formation of solid solutions (U,Th)O2+x(s) are suggested to be responsible for the lower solubility concentrations. For pH > 4, the final concentrations seems to be similar to pure phase solubility.
Complex formation of calcium with humic acid and polyacrylic acid
Authors: Kirishima Akira , Tanaka K. , Niibori Yuichi , Tochiyama Osamu
Published: September 2005

In order to understand the migration behavior of radionuclides in the underground, it is also important to estimate the effect of the competing cations originally present in the groundwater. In this connection, the complexation of Ca(II) with Aldrich humic acid has been examined. For the study at trace concentrations (∼10−10M) of Ca(II), the solvent extraction of45Ca with TTA and TOPO in cyclohexane has been used. At macro concentrations (10−4M) of Ca(II), the measurement of the free Ca2+ion concentration with a calcium selective electrode has been conducted. To estimate the polyelectrolyte effect of humic acid separately from its heterogeneous composition effect, polyacrylic acid ([-CH2CH(COOH)-]n) has been selected as a representative of the homogeneous polymeric weak acids and its complexation with Ca(II) has also been examined. The values of logβαhave been obtained at pH 5∼7 in 0.1, 0.4 and 1.0 M NaCl, where βαis the apparent formation constants defined by βα=[ML]/([M][R]). In this definition, [ML] and [M] are the concentrations of bound and free Ca2+respectively, [R] is the concentration of dissociated proton exchanging sites. logβαof humate decreases from 2.19∼2.92 (depending on pH and ionic strength 1.0 <I< 0.4) at pCa= 10 to 1.98∼2.44 at pCa = 4, while the variation of pCa has no appreciable influence on the logβαof polyacrylate (1.36∼3.24 forI=0.1∼1.0). For both humate and polyacrylate, logβαdecreases linearly with log[Na+], where [Na+] is the bulk concentration of sodium ion. Their dependences of logβαon ionic strength are stronger than those of logβ of monomeric carboxylates such as oxalate and EDTA, indicating the large electrostatic effect of crowded negative charges on the macromolecules of humic or polyacrylic acid.
Complexation of americium with humic, fulvic and citric acids at high ionic strength
Authors: Wall N. A. , Borkowski M. , Chen J. , Choppin Gregory R.
Published: September 2005

The stability constants of the Am3+ complexes of humic, fulvic and citric acids (HA, FA and Cit) were determined as a function of ionic strength (NaCl) using a solvent extraction technique. At a HA degree of ionization of 0.7 for the carboxylate groups, the Am-HA binding constant, logβ1, varies from 8.3 at I = 0.2 m to 7.2 at I = 6.0 m. The logβ1 of Am-Cit varies from 5.9 at I = 0.3 m to 5.10 at I = 5.0 m. Comparison of the binding constants of Am with HA, FA and Cit shows that, at high ionic strength, logβ1(AmCit) ≈ logβ1(AmFA) ≈ logβ1AmHA-1. Comparison of the values of other metals indicate that the logβ1 values for Cit can serve to estimate HA and FA.
Complexation of uranium(VI) with malonate at variable temperatures
Authors: Rao L. , Jiang J. , Zanonato P. , Di Bernardo P. , Bismondo A. , Garnov Alexander Yu.
Published: September 2005

The complexation between uranium(VI) and malonate in 1.05 mol kg−1 NaClO4 was studied at variable temperatures (25, 35, 45, 55 and 70 °C). The formation constants of three successive complexes, UO2(OOCCH2COO), UO2(OOCCH2COO)2
2− and UO2(OOCCH2COO)3
4−, and the molar enthalpies of complexation were determined by potentiometry and calorimetry. The heat capacity of the complexation, Δ Co
p,m(MLj), is calculated to be 96 ± 12, 195 ± 15 and 267 ± 22 J K−1 mol−1 for j=1, 2 and 3, respectively. Extended X-ray Absorption Fine Structure Spectroscopy helped to characterize the coordination modes in the complexes in solution. UV/Vis absorption and luminescence spectra at different temperatures provided qualitative information on the temperature effect. The effect of temperature on the complexation between uranium(VI) and malonate is discussed in terms of the electrostatic model and compared with the complexation between uranium(VI) and acetate.
The hydrolysis of uranium(VI)
Authors: Brown P. L.
Published: September 2005

The hydrolysis of uranium(VI) has been investigated in 0.10 mol dm−3NaClO4and KCl and 1.0 mol dm−3KNO3using the potentiometric technique. The results of the data analysis have been combined with data previously obtained from this laboratory and the literature to provide a more definitive description of the hydrolysis behaviour of uranium(VI). The species UO2OH+, (UO2)2(OH)22+, (UO2)3(OH)42+, (UO2)3(OH)5+and (UO2)4(OH)7+have been identified in nitrate media and all but the last of these species in chloride and perchlorate media. The differences in the complexation behaviour in the media may be due to oxoanion binding by the nitrate, a process which has also been observed for sulfate.
Corrosion and dissolution studies of UO2 containing α-emitters
Authors: Cobos J. , Havela L. , Rondinella V.V. , de Pablo Joan , Gouder T. , Glatz J.-P. , Carbol P. , Matzke Hj.
Published: September 2005

Corrosion and dissolution of UO2 doped with short-lived α-emitters, the so called α-doped UO2, was investigated in leaching experiments combined with X-ray Photoelectron Spectroscopy (XPS) analyses. These experiments are part of an ongoing set of tests aiming at evaluating the effects of α-radiolysis on the dissolution of the UO2 spent fuel matrix when it will become exposed to groundwater in a deep final repository. Pellets of UO2 containing ∼10 and ∼0.1 wt.% 238Pu were used. These compositions simulate the α-radiation field of different types of commercial LWR spent fuel after different storage times. Undoped UO2 pellets were also used as reference. Static sequential leaching experiments in demineralised water at room temperature under anoxic conditions confirmed that higher fractions of uranium are released in the case of α-doped materials compared with undoped UO2. Relatively large amounts of plutonium were found in the leachate of the materials doped with 238Pu. Significant contributions to the total amount released of uranium were found in the rinse solutions of the leaching vessels. The evolution of the U(VI)/U(IV) ratio on the leached surfaces as a function of contact time was studied by deconvolution of the 4f7/2 uranium peak obtained from the XPS spectra. In the case of undoped UO2, after ∼1000 h of leaching the increase of the U(VI)/U(IV) ratio stabilized to a level corresponding to ∼UO2.33. The XPS results for both α-doped materials showed a continuing increase of the U(VI) fraction on the surface with increasing leaching times after the first ∼10 h. The rate of increase depended on the α-activity of the fuel sample, hence on the amount of radiolysis in the water. After ∼1000 h of leaching, essentially only U(VI) was detected on the surface of the high activity α-doped UO2. The presence of a yellowish layer of reprecipitated U(VI) phases covering the surface could be observed optically already after ∼100 h of leaching.
Radiolytic formation of Tc(IV) oxide colloids
Authors: Sekine Tsutomu , Narushima H. , Kino Y. , Kudo Hiroshi , Lin M. , Katsumura Y.
Published: September 2005

Technetium(IV) oxide colloids were radiolytically formed by γ irradiation of aqueous solutions of pertechnetate (TcO4−). Pertechnetate solutions (5.5×10−5-2.9×10−4M) were irradiated with bremsstrahlung from an electron linear accelerator at 40 and 17 °C. The color of irradiated solutions gradually changed to brownish black, suggesting the formation of Tc(IV) oxide colloids (TcO2·nH2O). A transmission electron microscopy (TEM) analysis showed that the size of colloids distributed around 30 to 130 nm in diameter. The characteristic X-rays from technetium and oxygen were simultaneously detected from colloid particles at the TEM measurements. Round-shaped colloids were produced by irradiation at 40 °C, whereas irregular-shaped colloid particles composed of tiny particles (2 nm in diameter) were produced at 17 °C. The concentration of TcO4−in the target solution gradually decreased with an increase of the absorbed dose, corresponding to an increase of the colloid yield. The yield of colloids sharply increased in the solution deaerated by Ar bubbling before irradiation, but strongly suppressed in the solution saturated with oxygen (O2) or nitrous oxide (N2O) gas. The fact suggests that hydrated electrons play an important role in the course of the reduction of TcO4−and that Tc(IV) oxide colloids were formedviasuccessive disproportionation reactions of Tc(VI) and Tc(V). The formation mechanisms of Tc(IV) oxide colloids are discussed.
Uptake of oxo-anions by cements through solid-solution formation: experimental evidence and modelling
Authors: Ochs Michael , Lothenbach B. , Giffaut E.
Published: September 2005

Uptake experiments were carried out with selenate and chromate on fresh and leached Portland and high-alumina cements; and in addition with selenate and selenite on synthetic ettringite. In all experiments with cements, exceptionally high uptake could be observed under conditions where significant amounts of secondary ettringite were formed. Experimental data obtained for pure ettringite corroborated the important role of this mineral phase. However, uptake kinetics show opposite trends in these two systems, which can be viewed as end-members of the same process: Where a fast precipitation of secondary ettringite occurred, initial uptake was high, with Kd values in the range of ≍1-5 m3/kg for Se(VI), but decreased with time. Uptake by pre-formed (primary) ettringite initially gave lower Kd values (≍0.1 m3/kg), which increased with time. After prolonged equilibration times, the two systems started to approach each other. Concurrent measurements of sulphate concentrations allowed to extract a mean partition coefficient for the solid-solution formation of selenite and selenate with ettringite. Based on this simple solid-solution model, a pragmatic quantitative relation was developed that permits to estimate Kd for Se(VI) on whole cement as a function of the concentrations of sulphate in the cement and in the solution. A test against experimental data shows reasonably good agreement between measurements and calculations. This relation can also be directly applied to estimate Kd values of chromate (and perrhenate) by different cements, indicating the same uptake mechanism. The approach may be less well suited for Se(IV), whose uptake on cement appears to be related mainly to minerals other than ettringite.
Iodine species uptake by cement and CSH studied by IK-edge X-ray absorption spectroscopy
Authors: Bonhoure I. , Scheidegger A. M. , Wieland E. , Dähn R.
Published: September 2005

The uptake of iodine species (I−/IO3−) by HCP (hardened cement paste) and a CSH (calcium silicate hydrate) phase under highly alkaline conditions has been investigated using X-ray absorption spectroscopy (XAS). The study was performed at the I K-edge (33.169 keV) instead of the I L3-edge (4.557 keV) to avoid interference with Ca (K-edge=4.038 keV), a major element in HCP and CSH phases. The XANES (X-rays absorption near-edge structure) spectra revealed no changes in the formal oxidation state of iodide (I(-I)−) and iodate (I(V)O3−) upon uptake by HCP and CSH. The EXAFS (extended X-ray absorption fine structure) oscillations from I−treated HCP and CSH samples were found to be extremely weak, limiting interpretation of the EXAFS data. The IO3−EXAFS spectra showed that the IO3−entity consisting of three oxygen atoms with a characteristic I-O distance (∼1.78 Å) is maintained upon uptake by HCP and CSH. XANES further indicated that CSH is not the uptake-controlling phase in HCP.
Sorption and reduction of neptunium(V) on the surface of iron oxides
Authors: Nakata K. , Nagasaki S. , Tanaka S. , Sakamoto Y. , Tanaka T. , Ogawa H.
Published: September 2005

Sorption and desorption experiments of Np on magnetite and hematite under aerobic and anaerobic conditions were carried out to investigate the possibility of reduction of Np(V) to Np(IV) at pH 4 to 8 within 7 days. The amount of sorbed Np on magnetite under anaerobic conditions was about 2 or 3 times greater than that under aerobic conditions. Furthermore, the results of desorption experiments indicated that the dominant sorption behavior of Np on magnetite under anaerobic conditions was quite different from that under aerobic conditions. The oxidation state of Np sorbed on the iron oxides was determined by extraction technique using 0.5 M TTA in xylene and 2.0 M HNO3solution from the solid phase after sorption experiment. 90% and 10% of extracted Np was Np(IV) for magnetite system under anaerobic and aerobic conditions, respectively. On the other hand, almost 100% of extracted Np was Np(V) for hematite system under both aerobic and anaerobic conditions. These results indicated that Np(V) was reduced to Np(IV) by Fe(II) in magnetite.

Redox reaction between Np(V) and Fe(II) was also studied in homogeneous solution without solid to decide if Fe(II) ions released from magnetite into silution or Fe(II) on the solid cause the reduction. Only 6% of Np(V) was reduced by Fe(II) at pH=4 and 6 even after 7 days. According to this result, it was conjectured that the reduction of Np(V) to Np(IV) takes place not in the liquid phase by Fe(II) ion but on the surface of magnetite.
Uptake mechanism of IO3
− to NO3
−-hydrotalcite
Authors: Toraishi T. , Nagasaki S. , Tanaka S.
Published: September 2005

The FT-IR (Fourier transform infrared spectroscopy) spectrum of IO3
− adsorbed in the interlayer of NO3
− hydrotalcite (HTNO3) was determined. The v
3 vibration modes of IO3
− split into two peaks. All peaks caused by adsorbed IO3
− were found to be shifted to the lower wavelength region relative to the peaks observed from IO3
− in the KIO3 crystal. This suggested that IO3
− adsorbed in the interlayer of HTNO3 has asymmetry different from the original C3v symmetrical structure of aqueous IO3
−. The structural position of IO3
− in the interlayer of HTNO3 was optimized using the CASTEP (Cambridge serial total energy package) code. This code is based on density functional theory (DFT) calculations for crystal structures. It was found that the hydroxyl groups bound to O atoms of IO3
− are not uniform. This may lead to the structural change of adsorbed IO3
−.
Structure alteration of C-S-H (calcium silicate hydrated phases) caused by sorption of caesium
Authors: Iwaida T. , Nagasaki S. , Tanaka S. , Yaita T. , Tachimori S.
Published: September 2005

The sorption behavior of Cs onto C-S-H (calcium silicate hydrated phases) was investigated by evaluating the effect of sorption on the C-S-H structure.

The C-S-H have a tobermorite-type layer structure. Each layer consists of central calcium and oxygen atoms sandwiched by silicate tetrahedral chains. Additional calcium and water are located in interlayer zones. The XRD spectra showed that the tobermorite-type layer degraded and that the sorption of Cs made the fragments of layer intergrowths much smaller. The fragmentation of the tobermorite-type layer was observed for C-S-H in contact with CsCl solution or with CsOH solution, but not for the C-S-H in contact with Na solution. Furthermore, 29Si NMR spectroscopy revealed that the sorption of Cs onto C-S-H induced cleavages of silicate chains in C-S-H. It was also suggested that the OH− ion contributed to breaking the silicate chains.
The effect of α-isosaccharinic acid on the stability of and Th(IV) uptake by hardened cement paste
Authors: Wieland E. , Tits J. , Dobler J. P. , Spieler P.
Published: September 2005

The effect of α-isosaccharinic acid (ISA) on Th(IV) uptake by hardened cement paste (HCP) has been investigated under alkaline conditions (pH 13.3). Prior to performing the uptake studies the stability of HCP was determined in the presence of ISA. It was observed that the formation of Ca-ISA complexes in solution enhances portlandite solubility. The fraction of portlandite dissolved from the HCP matrix depends on the solid to liquid (S/L) ratio of the system and the ISA concentration in solution. Th(IV) uptake by HCP was found to be reduced above an aqueous ISA concentration of about 0−4 M. Reduction of Th(IV) uptake can be modelled taking into account the formation of a Th:ISA:Ca=1:2:1 complex in solution. It is indicated that the formation of ternary Th(IV)-ISA complexes may be important in cement systems. The final interpretation of the data however fails due to the large uncertainties in the distribution ratios measured in the absence of ISA.
Instrumental development for spectroscopic speciation off-elements in hydrothermal solutions: luminescence properties of lanthanide(III) ions
Authors: Kimura T. , Nagaishi R. , Arisaka M. , Ozaki Takuo , Yoshida Z.
Published: September 2005

An optical cell system for spectroscopic speciation off-elements in hydrothermal solutions was developed and applied to study the luminescence properties of lanthanide[Ln](III) ions by time-resolved laser-induced fluorescence spectroscopy. The apparatus to maintain the hydrothermal conditions consists of a HPLC pump, an optical cell with three sapphire windows, an electric furnace, a back pressure regulator,etc. Temperature and pressure of sample solutions can be controlled independently in the range of ambient conditions to 723 K and 40 MPa, respectively. Emission spectra and lifetimes of Ln(III) in HClO4solutions were measured as a function of temperature and pressure. The pressure effect on the emission spectra and lifetimes was not observed in the range of 0.1 to 40 MPa at a constant temperature. From the temperature dependence of the luminescence properties at 40 MPa, it was found that Ln(III) exist as a hydrated ion up toca. 500 K and that the variation of the luminescence properties at higher temperature is mainly due to the hydrolysis of Ln(III). Thermodynamic parameters and isotope effects for the quenching of excited Ln(III) in H2O and D2O solutions were also estimated from the temperature dependence of the luminescence lifetimes.
Application of microprecipitation on membrane filters for Alpha Spectrometry, liquid scintillation counting and Mass Spectrometric determination of plutonium isotopes
Authors: Hrnecek E. , de las Heras L. A. , Betti M.
Published: September 2005

For the determination of plutonium isotopes in environmental samples, chemical separation of plutonium together with a suitable sample preparation method for measurement is necessary. In this work, a combined method for the determination of238Pu,239Pu,240Pu and241Pu based on alpha spectrometry, Liquid Scintillation Counting (LSC) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is presented. For the alpha spectrometric determination of238Pu and239(40)Pu, sample preparation by coprecipitation of Pu with NdF3on a membrane filter after separation by anion exchange, using242Pu as tracer, is widely used. This sample preparation method was also applied as a preconcentration step for the determination of240Pu/239Pu ICP-MS after wet ashing of a part of the membrane filter.241Pu was measured with LSC after dissolving a part of the same membrane filter in a suitable cocktail and using the total alpha activity of the filter for determination of the chemical yield.

The use of this approach gives the advantage of combining the strengths of both radiometric and mass spectrometric methods for plutonium determination after chemical separation from environmental samples.

Results from the measurement of reference materials and from sediment samples from the Irish Sea are presented and the applied methods are compared with respect to their detection limits for the investigated nuclides.
Characterization of aquatic colloids by a combination of LIBD and ICP-MS following the size fractionation
Authors: Bouby M. , Ngo Manh T. , Geckeis Horst , Scherbaum Franz J. , Kim Jae-Il
Published: September 2005

Humic colloids in deep groundwater are characterized in order to ascertain how heavy metal ions of chemical homologue to actinides are associated in different size fractions. The colloid size fractionation is made by two different methods: flow field flow fractionation (FFFF) and size exclusion chromatography (SEC), which is followed by analysis of chemical composition using UV spectroscopy for organic components and ICP-MS for inorganic components. Relative number density of humic colloids following the size fractionation is determined by laser-induced breakdown detection (LIBD). For the appraisal of colloid size change upon metal ion complexation, purified Aldrich humic acid is loaded with the Eu3+ion on increasing the concentration and the size change is then determined by LIBD. Humic colloids are interacted with radioactive tracers,155Eu(III) and228Th(IV), to appreciate their sorption behaviour onto different colloid size fractions and thus to compare with natural humic colloid-borne elements of M(III) and M(IV).

Whereas the organic component of humic colloids is found in the size range about 3 nm, the inorganic components of actinides homologues, M(III) and M(IV), are observed in the fractionated size range from 10 nm to 35 nm. This observation leads us to presume that the inorganic composites, composed of heavy metal elements, are peptised by humic/fulvic acid. The laboratory traced elements,155Eu(III) and228Th(IV), are quantitatively sorbed only onto the organic component. This fact infers the complexation of traced metal ions with humic components of colloids without visible interaction with the inorganic components. Once purified humic acid is complexed with Eu(III) in an excess amount, the size increases over 200 nm and the resulting products undergo flocculation or precipitation. The results of the present experiment indicate that the natural humic colloid-borne heavy metal ions appear in different chemical states as compared to the same but laboratory traced metal ions. As a result, the laboratory simulation entails a better understanding of the underlying molecular level chemical reactions, which are important to the assessment of the colloid-borne actinide migration.
The use of electromigration as a qualitative technique to study the migration behaviour and speciation of uranium in the Boom Clay
Authors: Maes N. , Moors H. , Wang L. , Delècaut Grègory , De Cannière P. , Put M.
Published: September 2005

Under the geochemical conditions prevailing in situ in the Boom Clay Formation (pH, Eh, …), calculations predict that U(OH)4 is the dominant uranium species present in the interstitial water and the concentration is solubility limited. However the boundary of the domain where the non solubility limited UO2(CO3)3
4− species dominates is very close. It is therefore of prime interest to know the correct speciation of uranium during the migration process.

Electromigration was used as technique with the advantage that it can provide information on the speciation because the movement of the species towards the electrodes depends on its charge and speciation. Electromigration experiments have been performed with preconditioned 233UO2(CO3)3
4− sources, starting from the hypothesis that this species should migrate without retardation towards the anode. Despite relatively long electromigration times, sufficient to displace strong retarded tracers, no displacement of the migration profile towards the anode was observed. All 233U remained near the source position, but the electropherograms clearly showed the presence of species moving towards the cathode. This indicates the presence of neutral or positively charged uranium species. These electropherograms are interpreted as a change in uranium valence state: reduction of UO2(CO3)3
4− and precipitation of U(IV) oxy-hydroxides near the source position. The solubility limited species, U(OH)4(aq), are carried with the pore water towards the cathode. The electromigration experiments indicate, in support of the speciation calculations, that the dominant migrating U-species is probably the solubility limited U(OH)4.
U6+phases in the weathering zone of the Bangombé U-deposit: observed and predicted mineralogy
Authors: Jensen K. A. , Palenik C. S. , Ewing Rodney C.
Published: September 2005

The mineralogy of the supergene-weathered Bangombé natural fission reactor (RZB) and surrounding uranium deposit has been analyzed and compared with the thermodynamically predicted minerals based on groundwater compositions. The primary U-minerals are uraninite UO2+xand minor coffinite (U[SiO4]·nH2O); sometimes with phosphorous. The U6+minerals include fourmarierite Pb1−x[(UO2)4O3−2x(OH)4+2x]·4(H2O), bassetite (Fe1−x2+Fex3+[(UO2)(PO4)]2(OH)x·8−xH2O); possibly associated with U(HPO4)2·2H2O and/or chernikovite ((H3O)2[(UO2)(PO4)]2·6H2O); torbernite (Cu[(UO2)(PO4)]2· 8-12H2O), Ce-françoisite-(Nd) (REE(UO2)3O(OH)(PO4)2· 6H2O), and uranopilite ((UO2)6(SO4)O2(OH)6(H2O)6·8H2O). Autunite (Ca[(UO2)(PO4)]2·10-12H2O) has also been reported. Thermodynamic equilibrium modeling was completed using Geochemist's Workbench¯ with an expanded data base and the groundwater composition (−112 mV ≤ Eh≤ 143 mV; pH = 5.96) at the base of RZB in drill-hole BAX03. The new ΔG0f,298.15data were obtained from the literature or estimated using the polyhedral contribution method. Based on the updated database,Eh-pHdiagrams predict that coffinite, U(HPO4)2·H2O and UOF2·H2O are the only stable U4+phases and that uranopilite, torbernite and bassetite will become stable during oxidative alteration. Except from UOF2·H2O, this is in accord with mineralogical observations. The role of Cu was predicted from log aCu-pH diagrams, which predicts that torbernite is stable at log aCu=3.98×10−14and pH≥2.2 at Eh=143 mV in BAX03 groundwaters. At Eh= −112 mV, torbernite is stable at pH>5.5. Soddyite ((UO2)2SiO4·2H2O) was predicted to form at the expense of coffinite, but soddyite has not been identified at Bangombé. Previous blind prediction modeling, often omitting P and S, had only predicted soddyite and haiweeite (Ca(UO2)2[Si5O12(OH)2]·4-5H2O) and hence, failed to predict the U6+minerals observed at Bangombé. The results stress the importance of SO42−and PO43−resulting from dissolution of accessory apatite, monazite and sulfides in the retardation of U owing to the formation of U6+sulfates and phosphates.
Spectroscopic studies on the interaction of U(VI) with Bacillus sphaericus
Authors: Panak Petra J. , Knopp R. , Booth C. H. , Nitsche Heino
Published: September 2005

We studied the interaction of U(VI) with vegetative cells, heat killed cells, spores, and decomposed cells of Bacillus sphaericus. The characterization of the formed complexes was performed by time-resolved laser fluorescence spectroscopy (TRLFS) and extended X-ray absorption fine structure spectroscopy (EXAFS). We observed no significant differences in the sorption behavior of vegetative and heat killed cells, whereas the spores showed a higher sorption of U(VI) (related to their dry weight). Regardless of the higher relative sorption of the spores of B. sphaericus, the fluorescence and EXAFS spectra of the vegetative cells, heat killed cells and spores were almost identical. Analysis of the data proved that U(VI) forms inner sphere complexes with organic bound phosphate groups on the cell surface. We observed no significant differences in the coordination numbers and the distances of the oxygen and phosphorus atoms in the inner coordination sphere.

After eight weeks, the vegetative cells of B. sphaericus were completely decomposed. Lysing of the cell walls and activity of enzymes led to a release of various decomposition products. We found that large amounts of H2PO4
− were released which caused a quantitative precipitation of bacterial U(VI) as UO2(H2PO4)2. The H2PO4
− was detected by Raman spectroscopy. The decomposed bacterial suspension showed the same fluorescence spectrum as UO2(H2PO4)2 which differed significantly from those of the bacterial U(VI) surface complexes.
Biotransformation of pertechnetate by Clostridia
Authors: Francis Arokiasamy J. , Dodge Cleveland J. , Meinken G. E.
Published: September 2005

Clostridia are strict anaerobic, spore-forming, fermentative bacteria commonly present in soils, sediments, and wastes; and, they play a major role in the decomposition of a wide variety of organic compounds. They also are involved in the reduction of iron, manganese, and uranium, thereby affecting their solubility. However, little is known of the ability of Clostridia to reduce technetium (Tc). We investigated the reduction and precipitation of pertechnetate by Clostridium sphenoides able to metabolize citrate as its sole carbon source, and Clostridium sp. capable of fermenting glucose but not citric acid. Both species reduced Tc(VII) to Tc(IV), although C. sphenoides did so at a greater rate and extent than Clostridium sp. The reduced Tc was predominantly associated with the cell biomass. It also was present in solution complexed with bacterial metabolic products (MW>5000). Adding diethylenetriaminepentaacetic acid (DTPA) to Clostridium sp. resulted in the formation of a soluble Tc(IV)-DTPA complex, whereas with C. sphenoides only a small amount of Tc was present in solution, indicating that insoluble Tc species were formed. These results suggest that Clostridia may play a major role in regulating the mobility of Tc under anaerobic conditions in wastes and subsurface environments.
Sorption modelling by Gibbs energy minimisation: Towards a uniform thermodynamic database for surface complexes of radionuclides
Authors: Kulik D. A.
Published: September 2005

Radionuclide sorption on mineral-water interfaces can be thermodynamically modelled, similar to solid-solution aqueous-solution systems (only in chemical elemental stoichiometry), if definitions of the standard and reference states, surface activity terms (SAT), and elemental stoichiometries of surface-bound species are unequivocally established. A pre-requisite is that a unique common value of the reference (site) density (Γo) must be part of the definitions of standard and reference states, while the sample- and surface-specific maximum density parameters (Γmax) be included into the SAT corrections to reproduce saturation of physically available adsorption sites instead of introducing the additional mass balance constraints. Subsequently, the standard partial molal properties of surface complexes at multiple surface types on different sorbents can be found, comparable with the standard molar properties of solids, gases and aqueous species. Using surface complexation models (SCM) of U(VI) adsorption on quartz and amorphous silica (SiO2) phases in GEM (Gibbs energy minimization) implementation, a feasible way is shown how to construct a uniform, internally consistent thermodynamic dataset for surface species of radionuclides; to use standard partial molal Gibbs energies Go
298 of surface species in sorption modelling; how to convert Go
298 values from/to log K or intrinsic adsorption constants log Kint to use in the law-of-mass action (LMA) speciation codes, and finally, into “smart Kd” values for the applications related to waste repository performance assessment.