bluuebunny/crossref_metadata_2025 huggingface dataset:
Early management of proximal humeral fractures with hemiarthroplasty
Authors: Kontakis G. , Koutras C. , Tosounidis T. , Giannoudis P.
Published: November 2008

We performed a comprehensive systematic review of the literature to examine the role of hemiarthroplasty in the early management of fractures of the proximal humerus. In all, 16 studies dealing with 810 hemiarthroplasties in 808 patients with a mean age of 67.7 years (22 to 91) and a mean follow-up of 3.7 years (0.66 to 14) met the inclusion criteria. Most of the fractures were four-part fractures or fracture-dislocations.

Several types of prosthesis were used. Early passive movement on the day after surgery and active movement after union of the tuberosities at about six weeks was described in most cases. The mean active anterior elevation was to 105.7° (10° to 180°) and the mean abduction to 92.4° (15° to 170°). The incidence of superficial and deep infection was 1.55% and 0.64%, respectively. Complications related to the fixation and healing of the tuberosities were observed in 86 of 771 cases (11.15%). The estimated incidence of heterotopic ossification was 8.8% and that of proximal migration of the humeral head 6.8%. The mean Constant score was 56.63 (11 to 98). At the final follow-up, no pain or only mild pain was experienced by most patients, but marked limitation of function persisted.
A three-dimensional reconstruction plate for displaced midshaft fractures of the clavicle
Authors: Shen J.-W. , Tong P.-J. , Qu H.-B.
Published: November 2008

This randomised study compared outcomes in patients with displaced fractures of the clavicle treated by open reduction and fixation by a reconstruction plate which was placed either superiorly or three-dimensionally. Between 2003 and 2006, 133 consecutive patients with a mean age of 44.2 years (18 to 60) with displaced midshaft fractures of the clavicle were allocated randomly to a three-dimensional (3D) (67 patients) or superior group (66). Outcome measures included the peri-operative outcome index, delayed union, revision surgery and symptoms beyond 16 weeks. CT was used to reconstruct an image of each affected clavicle and Photoshop 7.0 software employed to calculate the percentage of the clavicular cortical area in the sagittal plane. The patients were reviewed clinically and radiographically at four and 12 months after the operation. The superior plate group had a higher rate of delayed union and had more symptomatic patients than the 3D group (p < 0.05). The percentage comparisons of cortical bone area showed that cortical bone in the superior distal segment is thicker than in the inferior segment, it is also thicker in the anterior mid-section than in the posterior (p < 0.05).

If fixation of midshaft fractures of the clavicle with a plate is indicated, a 3D reconstruction plate is better than one placed superiorly, because it is consistent with the stress distribution and shape of the clavicle.
The Jaipur foot
Authors: Arya A. P. , Klenerman L.
Published: November 2008

The Jaipur foot was developed for barefoot amputees by Professor P. K. Sethi. He used local artisans and readily available materials. The prosthesis was cheap and could be made in one hour. It enabled amputees to work in rural conditions, muddy and wet fields and to climb trees. It has been widely used in India, South East Asia and Africa, where local variations to the design have now been made.
Consenting Practice for Open Inguinal Hernia Repairs – Are We Failing to Warn Patients of Serious Complications?
Authors: Hoosein Moinuddin M , Towse Hilary , Conn Gemma , Stoker David L
Published: November 2008

INTRODUCTION

Open inguinal hernia repairs are one of the most commonly performed procedures in the UK. The procedure can sometimes result in considerable morbidity. It is imperative that the consenting process for this procedure is meticulous. This allows the patient to make a fully informed decision as they are aware of potential complications. In turn, this reduces the risk of future litigation. The aim of this study was to examine the adequacy of consenting for open inguinal hernia repairs, in particular, focusing on serious risks associated with the procedure.

PATIENTS AND METHODS

The notes of male patients who had undergone open inguinal hernia repair over a 6-month period were identified by the IT department. Inclusion and exclusion criteria were defined, giving a total of 97 male patients. Their consent forms were examined, focusing on: (i) the complications mentioned; and (ii) the grade of the consentor. A proforma was filled in for each of these patients and the data collated.

RESULTS

Of the 97 patients in the study, 25.7% of patients were consented by a consultant, 54.6% by a specialist registrar, and 19.6% by a senior house officer/FY2. The most commonly recorded risks included infection (100%) and bleeding (100%). Serious complications such as chronic pain (consented for at an average of 14%), testicular complications (45.3%) and visceral injury (52.1%) were poorly accounted for at all levels.

CONCLUSIONS

Consultants and juniors alike are not adequately consenting patients for inguinal hernia repairs, omitting serious complications such as chronic pain, recurrence and testicular complications. This leaves surgical teams vulnerable to claims for negligence. Good consenting practice may ultimately benefit both patient and surgeon.
Effectiveness of instructor behaviours and their relationship to leadership
Authors: Patrick John , Scrase Gemma , Ahmed Afia , Tombs Michal
Published: November 2008

This study analysed qualitatively the nature of instructor behaviours and their relationship to leadership. The Critical Incident Technique was used to collect effective and ineffective incidents of instructor behaviour in military training from both instructors' and trainees' perspectives (total incidents = 1150, effective = 696, ineffective = 494), across the three UK Armed Services. Nine dimensions of instructor behaviour were developed with high inter‐ and intra‐coder reliability. No differences were found between instructor and trainee generated incidents or among the three Armed Services. About 82% of the incidents could be recoded with high inter‐coder reliability into categories of both transformational and transactional leadership. Strong relationships emerged between the following dimensions of both instructor behaviour and leadership respectively: Showing and Demonstrating, and Appropriate Role Model; Using Instructional Strategies and Intellectual Stimulation; Feedback, Practice and Adapting, and Individual Consideration; Forms of Punishment and Control, and Contingent and Non‐contingent Punishment. These results inform not only the relationships between instructor behaviours and leadership but also the future training of military instructors, particularly the balance between a traditional authoritarian approach and an individualised supportive one.
Feline Pulmonary Langerhans Cell Histiocytosis with Multiorgan Involvement
Authors: Busch M. D. M. , Reilly C. M. , Luff J. A. , Moore P. F.
Published: November 2008

Histiocytic proliferative diseases are uncommon in cats, although recently a progressive histiocytosis of the skin with terminal involvement of internal organs has been described in cats. Here we describe 3 cats (2 males and 1 female) with pulmonary Langerhans cell histiocytosis (PLCH). The cats were euthanized due to progressive respiratory clinical symptoms and deterioration. Macroscopically, extensive, multifocal to confluent, pulmonary masses were evident. Infiltration of pancreas (2 cats), kidneys (1 cat), liver (1 cat), as well as tracheobronchial, hepatosplenic, or mesenteric lymph nodes (2 cats) was observed by gross or microscopic examination. The infiltrating cells had histiocytic morphology with cytologic atypia characterized by anisokaryosis and hyperchromasia regionally within infiltrated tissues. Lesional histiocytes expressed vimentin, CD18, and E-cadherin. Expression of E-cadherin was usually markedly reduced in extra-pulmonary lesions, which is consistent with possible down-regulation of E-cadherin associated with distant migration from the lung. Transmission electron microscopy demonstrated intracytoplasmic organelles consistent with Birbeck's granules of Langerhans cells in the lesional histiocytes in all cats, except in the pancreas of one cat. These findings were compatible with PLCH with limited organ involvement of humans. It remains unproven whether feline PLCH represents a reactive or neoplastic cell proliferation.
Review Paper: Modulation of Mononuclear Phagocyte Function by Mycobacterium avium subsp. paratuberculosis
Authors: Weiss D. J. , Souza C. D.
Published: November 2008

Pathogenic mycobacteria are highly adapted for survival within host mononuclear phagocytes. This is largely due to the organism's capacity to prevent macrophage activation, block phagosome acidification and maturation, and attenuate presentation of antigens to the immune system. Mycobacterium avium subsp. paratuberculosis (MAP) is one such organism that modulates the ruminant innate immune response. It is the causative agent in paratuberculosis, a chronic progressive granulomatous enteritis in ruminants. MAP initially interacts with cell membrane receptors on bovine mononuclear phagocytes and initiates cell signaling responses and phagocytosis. Mannosylated liparabinomannan (Man-LAM) is a major component of the MAP cell wall that interacts with the cell membrane of mononuclear phagocytes and may be a major virulence factor. Toll-like receptor 2 (TLR2) has been incriminated as major signaling receptor that binds to MAP and initiates signaling though the mitogen-activated protein kinase (MAPK)-p38 pathway. This pathway induces transcription of interleukin (IL)-10. Early production of IL-10 suppresses proinflammatory cytokines, chemokines, IL-12, and major histocompatability factor class-II expression. Both IL-10 dependent and IL-10 independent mechanisms appear to be involved in attenuation of phagosome acidification and phagolysosome fusion. Many of the suppressive effects of MAP on bovine mononuclear phagocytes can be reproduced by exposure of bovine monocytes to Man-LAM. Therefore, MAP Man-LAM-induced TLR2-MAPK-p38 signaling with resultant excessive IL-10 expression has emerged as one of the mechanisms by which MAP organisms suppress inflammatory, immune, and antimicrobial responses and promote their survival within host mononuclear phagocytes.
Survival of Dogs Following Surgical Excision of Histologically Well-differentiated Melanocytic Neoplasms of the Mucous Membranes of the Lips and Oral Cavity
Authors: Esplin D. G.
Published: November 2008

Postsurgical follow-up information was obtained on 64 dogs with 69 histologically well-differentiated melanocytic neoplasms that involved the mucous membranes of the lips and oral cavity. The patients received no adjunct therapy. Sixty one of 64 dogs (95%) were alive at the end of the study or had died of causes unrelated to the tumor, with a mean survival of 23.4 months and a median survival of 34 months after surgery. Twenty-eight dogs alive at the end of the study had a mean survival of 31.3 months after surgery. There were 2 dogs, which had recurrent tumors, that were still alive at the end of the study. All dogs that died of tumor-related causes (3) and all dogs with recurrent tumors (2) had tumors in the oral cavity.

Results of this study indicate that a favorable clinical course and prolonged survival can be expected in most dogs with histologically well-differentiated melanocytic neoplasms of the mucous membranes of the lips and oral cavity, with only local excision of the lesions and no adjunct therapy.
Obstructive Protein Cast Nephropathy in Cynomolgus Monkeys Treated with Small Organic Molecules
Authors: Guzman R. E. , Datta K. , Khan N. K.
Published: November 2008

We have observed a renal toxicity consistent with an obstructive protein cast nephropathy in cynomolgus macaques but not in other species treated with different therapeutic candidates having a common carboxylic acid moiety, suggesting a species-specific sensitivity. Here, we present renal toxicity findings consistent with a protein cast nephropathy in a 2–week safety study in cynomolgus monkeys. Light microscopic changes consisted of intratubular cast formation, tubular dilatation, interstitial inflammation, and expansion of the medullary interstitium. Tubular cast material was identified as Tamm-Horsfall protein (THP) and, on ultrastructure, crystalloid material was present in vacuoles of tubular epithelium. It is hypothesized that microcrystal formation in the urinary tubular spaces induces aggregation of THP protein and cast formation in monkeys. Drug-induced obstructive nephropathy is not identified as a major problem in humans; thus, the clinical relevance of the above findings in monkeys is not clear.
Diagnostic Exercise: Astrocytoma with Involvement of Medulla Oblongata, Spinal Cord, and Spinal Nerves in a Raccoon (Procyon lotor)
Authors: Hamir A. N. , Picton R. , Blythe L. L. , Heidel J. R.
Published: November 2008

Neoplasms affecting the central and peripheral nervous systems of wild animals are extremely rare. Described are clinical signs and pathologic and immunohistochemical findings in an adult female raccoon ( Procyon lotor) with an astrocytoma that involved medulla, cervical spinal cord, and roots of the cervical spinal nerves. Microscopically, the neoplastic cells revealed some pleomorphism but generally had fusiform morphology and showed moderate numbers of mitotic figures. Glial fibrillary acidic protein was demonstrated within the neoplastic cells by immunohistochemistry. This appears to be the only reported case of astrocytoma that involved multiple anatomic sites in the central nervous system of this raccoon.
Computer Simulation of Quenched Steel Working Stress
Authors: Smoljan B. , Smokvina Hanza S. , Iljkić D.
Published: November 2008

The possibility of the application of a modified Jominy-test in the computer simulation of quenching of steels for tools and dies has been investigated. The performance of an investigated modified Jominy-test in the simulation of quenching of tools and dies was estimated by a comparison of the cooling curves of a modified Jominy-specimen (JM®-specimen) and a cylindrical specimen. The hardness distribution in a quenched specimen was estimated based on a relevant cooling time from 800 to 500°C, as well as on the results of a modified Jominy-test. The characteristic cooling time, relevant for the results of quenching, was predicted by the computer simulation of quenching of both the JM®-specimen and cylindrical specimen. Mechanical properties of quenched steel directly depend on the degree of quenched steel hardening. The algorithm of the estimation of yield strength and fracture toughness on the base of steel hardness is established in this paper. Using the established algorithm, the mechanical properties of quenched and tempered die steel were estimated by computer simulation. It was found that the modified Jominy-test can be applied in the simulation of quenching of high hardenability steel more successfully than by the original Jominy-test.
Warnings and Instructions: One of Three Legs on Ice Hockey’s Safety Stool
Authors: Granger Mark S. , Miosek Ryan W.
Published: November 2008

Ice hockey is a fast-moving, action-packed contact sport. With any high-action sport there is a risk of serious personal injury and possibly even death. The combination of fast play, substantial contact, and high speed with good-size force, hard ice, and unyielding boards creates potential for injury. The sport has responded to these factors by controlling and setting rules for play, designing protective equipment to reduce the risk of serious personal injury or death, and providing warnings and instructions both on protective gear and through the amateur leagues and school coaching. This paper will primarily deal with this third leg of the safety stool with a primary emphasis on the warnings and instructions provided on the actual equipment and with accompany materials.
Discrepancies in thorium oxide solubility values: a new experimental approach to improve understanding of oxide surface at solid/solution interface
Authors: Vandenborre Johan , Abdelouas A. , Grambow Bernd
Published: November 2008

The solubility of ThO2(cr) was studied since many years but a large discrepancy in solubility values is noticed in the literature. The present work suggests that this discrepancy is related to differences in the surface properties of thorium oxide.

To understand the role of surface properties on solubility values, we conducted experiments with ThO2(cr) spheres with reproducable surface properties. Batch dissolution experiments were conducted in 0.01 M NaCl solution at pH=3.0 and 4.0 for periods of time up to 270 days. The solutions were spiked with229Th to determine precipitation (sorption) rates of thorium, while dissolution rates were determined by measuring232Th released from ThO2(cr) spheres. We assume that229Th atoms are exchanged only with active sites involved in Th-dissolution. Using229Th as local sensor of attachement and detachment processes at the ThO2(cr) surface under close-to-equilibrium conditions, allows to assess surface reactivity of the solid during solubility experiments.
Modeling plutonium solubility for Yucca Mountain performance assessment
Authors: Chen Y. , Pearson F. J.
Published: November 2008

The Yucca Mountain performance assessment requires a Pu solubility model over a broad range of environmental conditions. Several Pu solubility models have been developed and evaluated for the Yucca Mountain Project. These models are 1) the theoreticalfO2model; 2) the empiricalEhupper limit model; and 3) the adjustedEhupper limit model. It is found that over the expected environmental conditions, Pu solubility is very sensitive to redox conditions and properly selecting the redox conditions to be modeled is the key to developing a realistic and defensible Pu solubility model. Analyzing the modeling results carefully and using experimental results as benchmarks suggest that the adjustedEhupper limit model is a realistic and yet defensible model to be used by the PA.
Uranium/technetium separation for the UREX process – synthesis and characterization of solid reprocessing forms
Authors: Poineau Frédéric , Du Mazaubrun Julie , Ford Doris , Fortner Jeffrey , Kropf Jeremy , Silva G.W. Chinthaka , Smith Nicholas , Long Kristy , Jarvinen Gordon , Czerwinski Kenneth R.
Published: November 2008

In the context of the demonstration of the UREX (uranium extraction) process, a separation of uranium and technetium using an anion exchange resin was performed on a simulant solution containing 98.95 g/L of238U and 130.2 mg/L of99Tc. After sorption on the resin, TcO4−was eluted with NH4OH, the eluting stream was treated, and the technetium converted to Tc metal (yield=52.5%). The purity of the compound was analyzed: it contains less than 23.8 μg of238U per gram of99Tc. Tc metal was characterized by X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS) spectroscopy; EXAFS analysis clearly confirms the hexagonal structure of the metal obtained after treatment. Uranium was converted to ammonium diuranate and to U3O8in a yield of 88.2%, analysis indicates that the compound contains less than 0.16 μg of99Tc per gram of ammonium diuaranate.
UO2dissolution in the presence of hydrogen peroxide at pH>11
Authors: Meca Sandra , Marti Vincenc , de Pablo Joan , Giménez Javier , Casas Ignasi
Published: November 2008

The dissolution of non irradiated UO2was studied in the presence of hydrogen peroxide (10−4 mol dm−3) at alkaline pH (11, 11.5, 12, and 13). Both hydrogen peroxide and uranium concentration in solution were determined as a function of time. The H2O2consumption was modelled considering a pseudo first order reaction, the rate constants obtained were 0.126±0.004 h−1, 0.126±0.003 h−1, 0.078±0.002 h−1, and 0.056±0.002 h−1at pH 11, 11.5, 12, and 13, respectively. The uranium concentrations measured at the end of the experiments were close to the solubility of sodium uranate (Na2U2O7). X-ray photoelectron spectroscopy showed that the surface of the solid was more oxidized at lower pH, indicating that at this pH the limiting step of the oxidative dissolution process is the dissolution of the U(VI) formed on the surface. At more alkaline pH values, the rate limiting step would be the oxidation of the UO2surface.
Solubility of Zr(IV), Th(IV) and Pu(IV) hydrous oxides in CaCl2solutions and the formation of ternary Ca-M(IV)-OH complexes
Authors: Altmaier Marcus , Neck Volker , Fanghänel Thomas
Published: November 2008

The solubility of Zr(IV), Th(IV) and Pu(IV) hydrous oxides is investigated at 22±2 °C in alkaline 0.1−4.5 M CaCl2solutions. Further studies are performed with Zr(IV) over the entire pH range in NaCl and CaCl2media, and with Zr(IV) and Th(IV) in alkaline Ca(ClO4)2solutions. The comparison of Zr(IV) data in different ionic media (NaCl, NaClO4, CaCl2and Ca(ClO4)2) of similar ionic strength shows that the solubility in the acidic and neutral pH range is not affected by strong interactions between the aqueous M(IV) species and the medium ions. However, in alkaline CaCl2and Ca(ClO4)2solutions the formation of ternary Ca-M(IV)-OH complexes causes unexpectedly high solubilities of Zr(IV) at pHc=10−12 and [Ca2+]>0.05 M and of Th(IV) at pHc=11−12 and [Ca2+]>0.5 M. The dependence of the Zr(IV) and Th(IV) solubilities on the H+and CaCl2concentrations shows that the complexes Zr(OH)62−and Th(OH)84−with an unusual large number of OH−ligands are stabilized by the formation of associates or ion pairs with Ca2+ions. The SIT is used to derive equilibrium constants at zero ionic strength for the complexes Zr(OH)62−(in calcium-free solutions), Ca2[Zr(OH)6]2+, Ca3[Zr(OH)6]4+and Ca4[Th(OH)8]4+. In analogous studies with Pu(IV) hydrous oxide, the solubility increasing effect of ternary complex formation with Ca2+ions is only observed at CaCl2concentrations above 2 M.
Thermodynamic interpretation of neptunium coprecipitation in uranophane for application to the Yucca Mountain repository
Authors: Murphy William M. , Grambow Bernd
Published: November 2008

Interpretation and modeling of recent experimental data [1] yield thermodynamic constants for the distribution of trace Np(V) between aqueous solutions and uranophane. These data indicate that neptunyl is relatively excluded from the uranyl mineral structure, but the interpretation depends on uncertain aqueous speciation and thermodynamic properties as a function of temperature. Despite Np exclusion, the low calculated solubility of uranophane at 25 °C under conditions relevant to the proposed nuclear waste repository at Yucca Mountain, Nevada, leads to Np concentrations at equilibrium with a Np-bearing uranophane solid solution that are low compared to concentrations invoked as solubility limits in Yucca Mountain performance assessments.
Synthesis, crystallographic characterization, and conformational prediction of a structurally unique molecular mixed-ligand U(VI) solid, Na6[UO2(O2)2(OH)2](OH)2·14H2O
Authors: Zehnder Ralph A. , Batista Enrique R. , Scott Brian L. , Peper Shane M. , Goff George S. , Runde Wolfgang H.
Published: November 2008

The first mononuclear molecular mixed-ligand U(VI) solid containing hydroxide and peroxide ligands, Na6[UO2(O2)2(OH)2](OH)2·14H2O (I), was synthesized and structurally characterized using single crystal X-ray diffraction. The crystal structure of I consisted of [UO2(O2)2(OH)2]4− molecular units, with a uranyl(VI) moiety perpendicular to 6 equatorial O atoms belonging to two side-on trans peroxo groups and two terminal trans hydroxo groups. Density functional theory (DFT) calculations determined that the trans -conformer of the [UO2(O2)2(OH)2]4− molecular unit found in I was 24 kcal/mol lower in energy than the previously proposed cis -conformer. Crystal data: monoclinic, space group P21/n with a=13.357(4) Å, b=5.8521(15) Å, c=15.948(6) Å, β=112.292(4)°, and Z=2.
Thermodynamic study on the U(VI) complexation with dicarboxylates by calorimetry
Authors: Kirishima Akira , Onishi Yuko , Sato Nobuaki , Tochiyama Osamu
Published: November 2008

The thermodynamic quantities (ΔG, ΔH and ΔS) of U(VI) complexation with oxalate, malonate, succinate, glutarate, adipate, phthalate, tartronate and malate, and of Eu(III) complexation with succinate, glutarate and adipate were determined by potentiometric and calorimetric titration techniques. The obtained thermodynamic quantities indicated that these complexation reactions are mainly driven by the entropy changes while the enthalpy changes are nearly zero or preventing the complexation. The thermodynamic quantities of 1:1 U(VI) complexes with 5 dicarboxylates having different carbon chain lengths (−OOC−(CH2)
n
−COO−) showed an interesting tendency, that is, −ΔH decreased and TΔS increased systematically with increasing the length of the carbon chain from n = 2 to 6. The comparison of TΔS values of 1:1 carboxylate formation with U(VI) and Eu(III) showed that TΔS of U(VI) were always lager than those of Eu(III). The entropies of 1:1 complex formation of U(VI) with hydroxycarboxylates were always smaller than those with carboxylates of the same carbon chain length, while the enthalpies of uranyl hydroxycarboxylates were always larger. This tendency was also observed in the protonation and the complex formation of Eu(III).
A cryogenic fluorescence spectroscopic study of uranyl carbonate, phosphate and oxyhydroxide minerals
Authors: Wang Zheming , Zachara John M. , Liu Chongxuan , Gassman P. L. , Felmy Andrew R. , Clark Sue B.
Published: November 2008

In this work we applied time-resolved laser-induced fluorescence spectroscopy (TRLIF) at both room temperature (RT) and near liquid-helium temperature (6 K) to characterize a series of natural and synthetic minerals of uranium carbonate, phosphate and oxyhydroxides including rutherfordine, zellerite, liebigite, phosphuranylite, meta-autunite, meta-torbernite, uranyl phosphate, sodium-uranyl-phosphate, becquerelite, schoepite, meta-schoepite, dehydrated schoepite and compreignacite, and have compared the spectral characteristics among these minerals as well as our previously published data on uranyl silicates. For the carbonate minerals, the fluorescence spectra of rutherfordine showed significant difference from those of zellerite and liebigite. The fluorescence spectra of the phosphate minerals closely resemble each other despite the differences in their composition and structure. For all uranium oxyhydroxides, the fluorescence spectra are largely red-shifted as compared to those of the uranium carbonates and phosphates and their vibronic bands are broad and less resolved at RT. The enhanced spectra resolution at 6 K allows more accurate determination of the fluorescence band origin and offers a complemental method to measure the O=U=O symmetrical stretch frequency, ν
1, from the spacings of the vibronic bands of the fluorescence spectra. The average ν
1 values appear to be inversely correlated with the average pK
a values of the anions.
A spectroscopic study of the effect of ligand complexation on the reduction of uranium(VI) by anthraquinone-2,6-disulfonate (AH2DS)
Authors: Wang Zheming , Wagnon K. B. , Ainsworth C. C. , Liu Chongxuan , Rosso Kevin M. , Frederickson K. J.
Published: November 2008

In this paper, the reduction rate of uranyl complexes with hydroxide, carbonate, EDTA, and desferriferrioxamine B (DFB) by anthraquinone-2,6-disulfonate (AH2DS) is studied by stopped-flow kinetic technique under anoxic atmosphere. The apparent reaction rates varied with ligand type, solution pH, and U(VI) concentration. For each ligand, a single largest pseudo −1st order reaction rate constant, k
obs, within the studied pH range was observed, suggesting the influence of pH-dependent speciation on the U(VI) reduction rate. The maximum reaction rate found in each case followed the order of OH−>CO3
2−>EDTA>DFB, in reverse order of the trend of the thermodynamic stability of the uranyl complexes and ionic sizes of the ligands. The pH-dependent rates were modeled using a second-order rate expression that was assumed to be dependent on a single U(VI) complex and an AH2DS species. By quantitatively comparing the calculated and measured apparent rate constants as a function of pH, species AHDS3− was suggested as the primary reductant in all cases examined. Species UO2CO3(aq), UO2HEDTA−, and (UO2)2(OH)2
2+ were suggested as the principal electron acceptors among the U(VI) species mixture in each of the carbonate, EDTA, and hydroxyl systems, respectively.
The relationship of monodentate and bidentate coordinated uranium(VI) sulfate in aqueous solution
Authors: Hennig Christoph , Ikeda A. , Schmeide K. , Brendler Vinzenz , Moll Henry , Tsushima S. , Scheinost A. C. , Skanthakumar Suntharalingam , Wilson R. , Soderholm L. , Servaes K. , et al.
Published: November 2008

The coordination of U(VI) sulfate complexes has been investigated by uranium L
III-edge EXAFS and HEXS measurements with the aim to distinguish monodentate and bidentate coordinated sulfate in aqueous solution. UV-vis absorption spectroscopy has been used to differentiate the species and to determine the species distribution as a function of the [SO4
2−]/[UO2
2+] ratio. A monodentate coordination prevails in solutions with [SO4
2−]/[UO2
2+] ratio of 1, where UO2SO4 is the dominant species. Besides the dominating monodentate sulfate a small amount of bidentate sulfate could be observed, indicating that two isomers may exist for UO2SO4. With increasing [SO4
2−]/[UO2
2+] ratio the UO2(SO4)2
2− species becomes the main species. The uranium atom of this species is coordinated by two bidentate sulfate groups.
Hydrolysis constants of tetravalent neptunium by using solvent extraction method
Authors: Fujiwara Kenso , Kohara Y.
Published: November 2008

The hydrolysis constants of tetravalent neptunium (Np(IV)) were determined by solvent extraction method using thenoyltrifluoroacetone(TTA). In order to avoid colloid formation, a stock solution of carrier-free 239Np(V) was from 243Am milked. The valence of Np in the solution was then reduced to Np(IV) by using zinc amalgam. The hydrolysis constants (β

m
) of the reactions, Np4++mOH−=Np(OH)
m

(4−m)+ was evaluated by using distribution ratios at ionic strengths (I)=0.1, 0.5 and 1.0. All experiments were performed in oxygen- free 0.5% H2−N2 atmosphere (below 1.0 ppm of O2) in a glovebox at room temperature (23±2 °C) to avoid oxidation of Np(IV). The β

m
values were extrapolated to the standard state (I=0) by using the specific ion interaction theory (SIT), and the formation constants at I=0 were determined to be logβ
1°=13.91±0.23, logβ
2°=27.13±0.15, logβ
3°=37.70±0.30 and logβ
4°=46.16±0.30. The ion interaction coefficients were also evaluated to be ε(NpOH3+, ClO4
−)=0.49±0.15, ε(Np(OH)2
2+, ClO4
−)=0.35±0.11, and ε(Np(OH)3
+, ClO4
−)=0.29±0.15.
Oxidative dissolution of Tc(IV)O2·nH2O colloids by sonolysis
Authors: Sekine Tsutomu , Zakir Muhammad
Published: November 2008

Redox reactions of Tc in aqueous solutions by sonolysis were investigated. Aqueous pertechnetate (Tc(VII)O4
−) solutions and Tc(IV)O2· n H2O colloids solutions were sonicated (200 kHz, 200 W) in a glass cell with flat bottom under Ar or He atmosphere at 20 °C. No reduction of TcO4
− was observed in this study. However, we found that the TcO2· n H2O colloids dispersed in an aqueous solution were completely dissolved by ultrasonic irradiation within 30 min under Ar atmosphere, and TcO4
− was eventually produced. The production of TcO4
− was considerably suppressed in the presence of t-butyl alcohol (an effective scavenger of OH radicals), indicating that Tc(IV) was oxidized by OH radicals (produced by dissociation of water molecules) in hot cavitation bubbles created by ultrasound. The formation rate of TcO4
− under He atmosphere was smaller than that under Ar atmosphere. This can be attributed to a difference of the effective maximum temperature in the collapsing bubbles. Because thermal conductivity of He is much higher than Ar, thermal transport effectively occurs from the bubbles to the surrounding liquid. Thus, temperature of cavitation bubbles filled with He should be lower than those filled with Ar, resulting in the smaller OH formation rate.
Sorption of selenium on Mg-Al and Mg-Al-Eu layered double hydroxides
Authors: Curtius Hilde , Paparigas Z. , Kaiser G.
Published: November 2008

Salt domes represent deep geological formations which are under consideration as final repositories for irradiated research reactor fuel elements. For long-term safety aspects the mobilisation of the radionuclides due to a water ingress is intensively investigated. At the Institute of Energy Research (IEF-6), leaching experiments were performed in a hot cell facility with UAl
x
-Al and U3Si2-Al dispersed research reactor fuel elements in repository-relevant MgCl2-rich salt brines under anaerobic conditions. The fuel plates corroded completely within one year and a Mg-Al-layered double hydroxide (LDH) with chloride as interlayer anion was identified as one crystalline phase component of the corrosion products (secondary phases). This Mg-Al-LDH was synthesized, characterized, and the ability to retard europium by an incorporation process was investigated. Europium, as a representative for lanthanides, was identified to be one of the radionuclides which were found in the corrosion products. We could show that europium was incorporated in the lattice structure. LDHs have high anion exchange capacities that enhance their potential to remove anionic contaminants from aqueous systems.

In this work the sorption behaviour of selenium in the chemical form as selenite (SeO3
2−) on Mg-Al-LDH and on Mg-Al-Eu-LDH was investigated. Especially the influence of the larger europium-III ion was of interest. It represents in the Mg-Al-Eu-LDH about 10% of the molar aluminium amount. The sorption has been experimentally studied in a wide range of pH, ionic strength, radionuclide and sorbent concentration. Both LDHs with chloride as interlayer anion were synthesized by a coprecipitation method under controlled conditions, and their main physico-chemical properties were analyzed prior to the sorption experiments.

The sorption kinetics of selenite on the LDHs in water and in MgCl2-rich brine were rapid using a LDH concentration of 10 g/L. Equilibrium, indicated by stable pH values, was obtained within 5 h for an initial selenite concentration of 4.28×10−13 mol/L. Selenite in water sorbed quantitatively on both LDHs. In MgCl2-rich brine a different behaviour to water was observed. The sorption was not quantitatively, due to the presence of high amounts of chloride anions. Chloride, as competing anion, affected the sorption behaviour of selenite. Using a LDH concentration of 0.1 g/L, the sorption of selenite was negligible. The effect of pH on selenite sorption was investigated, too. The sorption was relatively constant when the initial pH values were adjusted between 4 and 8, because both LDHs exhibit a high pH buffering capacity. For a selenite concentration range between 5.43×10−14 and 3.24×10−12 mol/L sorption isotherms were obtained and the data could be fitted to Freundlich and Dubinin–Radushkevich equations. The sorption capacities of the LDHs and the energies of sorption were determined. The sorption of selenite occurred via an ion exchange mechanism and the sorption behaviour was similar for both LDHs.
Studies of the ternary systems humic substances – kaolinite – Pu(III) and Pu(IV)
Authors: Buda R. , Banik N. L. , Kratz Jens Volker , Trautmann N.
Published: November 2008

The behaviour of plutonium with respect to its migration in the aquifer has been studied under conditions close to nature. Most relevant under these conditions are Pu(III) and Pu(IV) in contact with humic substances (HS) and minerals. As a model for the host rock, kaolinite (KGa-1b) was chosen. The complexation of Pu(III) and Pu(IV) with Aldrich humic acid (AHA) in aqueous solution at ionic strength 0.1 M was investigated by the ultrafiltration method. The sorption of Pu(III) and Am(III) onto kaolinite (K) as a function of pH and metal-ion concentration was studied under aerobic and anaerobic conditions. The pH edge was found at pH∼5.5 independent of the metal-ion concentration and working atmosphere. The influence of HS on the sorption of Pu(III) and Pu(IV) onto kaolinite was investigated in the ternary systems Pu(III)-K-HS and Pu(IV)-K-HS and for comparison, in the system Th(IV)-K-HS. The dependence on pH, contact time, concentration of HS (for Pu(IV)-K-HS) was studied as well as the sequence in which the components were added. Generally, it was found that HS tend to enhance the sorption onto kaolinite below pH 6 and to decrease sorption at higher pH depending in detail on the sequence in which the components were added. An identification of the species sorbed on the surface of the kaolinite by X-ray absorption spectroscopy, as well as chemically, was attempted and preliminary results are discussed.
Polarized EXAFS characterization of the sorption mechanism of yttrium on hectorite
Authors: Schlegel Michel
Published: November 2008

Yttrium uptake in 2 g/L hectorite suspensions at high ionic strength (0.5 M NaCl) as a function of pH (6.5 and 7) and total Y concentration (10 and 50 μM) was investigated by solution chemistry and Polarized EXAFS (P-EXAFS) spectroscopy. At pH 6.5, Y uptake readily occurred, but equilibrium was not attained within 96 h of reaction. A greater fraction of Y was sorbed at pH 7, and near-equilibrium conditions were attained after 48 h of reaction.

Polarized EXAFS data indicated that the environments of Y sorbed at the two pH values were structurally similar. Yttrium was surrounded by a split first coordination sphere of four O atoms at 2.27−2.28 Å and four O at 2.43 Å. The averaged(Y-O) distance agrees with eight-fold coordination of Y. Neighboring cationic shells of Mg atoms at 3.16−3.18 Å oriented at the magic angle and out-of-plane Si atoms at 3.48−3.51 Å were also detected. These distances and orientations are consistent with Y forming inner-sphere surface complexes at layer edges of hectorite by sharing edges with Mg octahedra and corner with Si tetrahedra. The observed angular dependence further suggests that Y is tilted away from the Mg-containing median planes of hectorite platelets.
Hydration and hydrolysys of Sm3+ and Eu3+ in a clay interlayer: a neutron diffraction study with isotopic substitution
Authors: Sobolev Oleg , Charlet L. , Cuello G. , Gehin A. , Brendle J.
Published: November 2008

The coordination of Sm and Eu in the montmorillonite interlayer was studied by neutron diffraction with isotopic substitution. It was found that the number of hydrogen atoms nearest to Sm and Eu were less (N
H=5.5±2.0) than oxygen nearest atoms (N
O=7.5±1.0). This means that the Sm and Eu are not surrounded only by hydration water molecules, but they are in contact with the oxygen siloxane atoms of the clay basal plane surface. It was found that the number of oxygen atoms of the clay surface giving a contribution to the total coordination number N
O should be N
O
clay≤3. Therefore, the deficit of hydrogen atoms in the first coordination shell of Sm and Eu should be explained supposing that the lanthanide cations are partially hydrolyzed.
Sorption of neptunium onto goethite in the presence of humic acids with different hydroquinone group content
Authors: Kalmykov Stepan N. , Schäfer Thorsten , Claret F. , Perminova I. V. , Petrova (Khasanova) A. B. , Shcherbina N. S. , Teterin Y. Al
Published: November 2008

Neptunyl sorption in the ternary system of goethite–humic acid (HA)–Np was studied in a series of batch experiments with natural leonardite HA and a hydroquinone enriched derivative. The reduction of Np(V) at low pH has been observed by XPS upon interaction with hydroquinone-enriched leonardite HA–goethite suspension. Under these low pH conditions the formation of humate coatings at the goethite mineral surface has been identified using scanning transmission X-ray microscopy (STXM) at the carbonK-edge.
The influence of carbonate complexation on lanthanide/actinide sorption on montmorillonite
Authors: Marques Fernandes Maria , Baeyens B. , Bradbury Michael H.
Published: November 2008

The safety case for radioactive waste repositories is, to a large extend based on the physical and chemical retention of radionuclides on clay minerals which are important constituents in both the man-made engineered barriers and in argillaceous host rock formations. The presence of carbonate, one of the most important inorganic ligands for lanthanide and actinide ions in groundwaters and clay porewaters, can have a significant influence on their sorption behaviour on clay minerals. The sorption of Eu(III) on Na-montmorillonite in the absence and the presence of carbonate was investigated in batch sorption experiments. In the presence of carbonate two sets of experimental conditions were investigated. Eu(III) sorption measurements were performed as a function of pH in equilibrium with atmosphericpCO2(=10−3.5 bar) and at a variablepCO2(=10−1.4to 10−3.4 bar). The sorption data were modelled using the 2 site protolysis non-electrostatic surface complexation and cation exchange model. Both experimental data sets in the presence of carbon could be quantitatively modelled by including in the sorption model two additional surface complexation reactions on the strong sites forming ≡SSOEuCO30and ≡SSOEuOHCO3−surface complexes.
Sorption of radionuclides onto natural clay rocks
Authors: Hartmann E. , Geckeis H. , Rabung Thomas , Lützenkirchen Johannes , Fanghänel Thomas
Published: November 2008

Reactions of U(VI) and Eu/Cm(III) with natural clay rock (Opalinus Clay, Switzerland, and Callovo-Oxfordian Clay, France) are investigated by batch and spectroscopic experiments as well as geochemical calculations. The aim of the studies is to identify those minerals in the heterogeneous multiphase systems with sometimes high calcite content which control lanthanide and actinide sorption. The outcome of batch sorption studies with natural clay rocks (2 g/L natural clay rock, 0.1 mol/L NaClO4, pH 3−11) and thermodynamic calculations is compared with experimental results using a synthetic mixture consisting of purified Na-montmorillonite and calcite (ratio 80:20[wt.]%). Our studies show that U(VI) sorption decreases at intermediate pH (6.5−9) where dissolved U(VI) carbonate species predominate. In the high pH region (>9) U(VI) sorption again increases by formation of ternary hydroxo surface complexes on the clay mineral fraction, whereby calculated U(VI) sorption overestimates experimental data for the natural rock. Complete sorption to natural clay rock and the synthetic clay/calcite mixture is observed for Eu(III) at pH>7 for the conditions studied. Model calculations again point to the predominance of clay-sorbed species even though calculated speciation underestimates the experimentally observed sorption at pH 6−9 slightly. Preliminary time-resolved laser-fluorescence spectroscopy (TRLFS) studies using Cm(III) as fluorescent probe reveal the appearance of several Cm(III)-clay surface species in the pH range 5−11, but give no indications for the presence of calcite-bound Cm(III). We conclude that the clay minerals in the multiphasic clay rock act as main sorbents for tri- and hexavalent actinides.
Sorption behavior of americium onto bentonite colloid
Authors: Iijima Kazuki , Shoji Y. , Tomura T.
Published: November 2008

In the geological disposal system, if colloids can stably exist in groundwater, radionuclides (RNs) might be sorbed onto the colloids and migrate long distance without retardation such as the sorption onto minerals and the matrix diffusion. The distribution coefficient (Rd), which is a measure for sorption onto colloids, is one of the sensitive parameters in evaluation of the effect of colloids on the RN migration. In this study, theRds of Am onto bentonite colloids were evaluated by batch sorption experiments under weakly basic and low ionic strength conditions. Colloidal species of Am seems to be generated even in the absence of bentonite colloids, however, it has less contribution toRd. The obtainedRdvalues are larger than those obtained for larger montmorillonite particles reported in literatures. The difference ofRdis considered to be due to a difference of composition of experimental solution and a difference of reactive site capacity affected by particle size. Site capacities of bentonite colloids are evaluated by acid titration and it is observed that bentonite colloids have about 8 times larger site capacities than bentonite sediments. A relatively simple and generalized mechanistic sorption model, 2SPNE SC/CE model, is applied to estimate theRdfor Am sorption onto bentonite colloids using reaction constants reported in literatures and site capacities obtained in this study. CalculatedRds mostly agree well with corresponding experimental data at pH 8, while,Rds are underestimated at pH 10. Based on the speciation plots, it is probably due to the underestimation of surface complexation reaction.
Vertical distribution of 238Pu, 239(40)Pu, 241Am, 90Sr and 137Cs in Austrian soil profiles
Authors: Srncik M. , Hrnecek Erich , Steier P. , Wallner A. , Wallner Gabriele , Bossew P.
Published: November 2008

The occurrence of 238Pu, 239(40)Pu, 241Am, 90Sr and 137Cs in the region of Nassfeld (Salzburg, Austria) is discussed at four different locations by evaluating a depth profile for each radionuclide. Furthermore, the plutonium separated from the soil samples was measured by Accelerator Mass Spectrometry (AMS) to get information on the isotope ratio 240Pu/ 239Pu. The radiochemical procedure consisted of a Pu separation step from Am and Sr by anion exchange in 8 M HNO3 after oxidation state adjustment to Pu(IV). Am and Sr were coprecipitated with calcium oxalate. Am was separated from Sr by extraction chromatography using TRU-resin. The Sr separation was performed also by extraction chromatography using Sr-resin; after coprecipitation as oxalate, 90Sr was measured in a gas proportional counter. For the determination of 239(40)Pu and 241Am by α-spectrometry thin sources were prepared by microprecipitation with NdF3.

With the respective Pu isotope ratios, it was possible to identify the global fallout as source of the contamination. This was confirmed by the ratio 241Am/239(40)Pu. From the activity ratio 90Sr/ 137Cs, it could be shown that most of these radionuclides stem from the reactor accident in Chernobyl.
Systemic Therapy for Advanced or Metastatic Colorectal Cancer: National Comprehensive Cancer Network Guidelines for Combining Anti‐Vascular Endothelial Growth Factor and Anti‐Epidermal Growth Factor Receptor Monoclonal Antibodies with Chemotherapy
Authors: Engstrom Paul F.
Published: November 2008

During the past decade, new therapies for colorectal cancer have emerged that significantly prolong survival times. The introduction of these new agents has resulted in changes in colorectal cancer treatment patterns; clinicians are now able to optimize therapy and minimize toxicity by developing individualized patient treatment plans using a variety of agents. Biologic agents, including bevacizumab, an anti‐vascular endothelial growth factor (VEGF) monoclonal antibody, and cetuximab and panitumumab, anti‐epidermal growth factor receptor (EGFR) monoclonal antibodies, are among the new therapies now recommended by the National Comprehensive Cancer Network (NCCN) colon and rectal cancer treatment guidelines for use in first‐, second‐, and/or third‐line colorectal cancer therapy. According to the NCCN guidelines, patients with advanced or metastatic colorectal cancer who are without contraindications are candidates to receive the anti‐VEGF and anti‐EGFR monoclonal antibodies at some point during the treatment course.