bluuebunny/crossref_metadata_2025 huggingface dataset:
The growth and form of ash (Fraxinus excelsior) in mixture with cherry (Prunus avium), oak (Quercus petraea and Quercus robur), and beech (Fagus sylvatica)
Authors: Kerr Gary
Published: December 2004

The effects of mixing ash (Fraxinus excelsior L.) with cherry (Prunus avium L.), oak (Quercus petraea (Matt.) Lieb., and Quercus robur L.), and beech (Fagus sylvatica L.) were investigated using a balanced two-component competition experiment. In general, two patterns of growth were observed. Firstly, in the ashcherry experiment, two rapidly growing species altered their stem form and showed a plastic response to interspecific competition, and both species maintained a position in the upper canopy. Secondly, in the ashoak and ashbeech experiments, a two-tier canopy formed with ash in the upper canopy, and interspecific competition resulted in an early nursing effect on the ash. In both patterns of growth, competition affected stem diameter and the shape of the tree with few, and only short-lived, effects on height. The maximum relative yield totals were 1.78 for ashcherry, 1.77 for ashoak, and 1.44 for ashbeech, indicating that the mixtures studied may be more productive in their early phase of growth than equivalent areas of pure species.
Variation among provenances and families of blackbutt (Eucalyptus pilularis) in early growth and susceptibility to damage from leaf spot fungi
Authors: Carnegie Angus J , Johnson Ian G , Henson Michael
Published: December 2004

Growth to 38 months and severity of Mycosphaerella leaf disease and target spot (caused by Aulographina eucalypti (Cooke & Mass.) von Arx & Muller) were assessed in a Eucalyptus pilularis Smith (blackbutt) family trial in New South Wales (NSW), Australia. Significant variation in growth, disease, and defoliation was found among the 40 provenances and 321 families tested; however, relatively few provenances had concentrations of superior or poor families. Most families in three higher altitude NSW provenances were superior for volume increment, while three southeast Queensland provenances had low mean volume increment. Mycosphaerella damage and defoliation tended to be low in several higher altitude northern NSW provenances, but the southeast Queensland provenances had significantly higher mean defoliation. Individual narrow sense heritability estimates were low to moderate for Mycosphaerella damage (0.38) and defoliation (0.22) and low for Aulographina damage (0.13) and volume increment (0.13). Significant genetic and phenotypic correlations between Mycosphaerella damage and defoliation were low and positive. Low to moderate negative correlations occurred between Mycosphaerella damage and volume increment and between defoliation and volume increment, suggesting that Mycosphaerella leaf disease, in particular, and defoliation had deleterious effects on tree growth. However, the impact of these foliar pathogens on the volume of E. pilularis is often low, so selecting for growth and form alone in the early stages of domestication could provide acceptable gains in yield.
Does coring contribute to tree mortality?
Authors: Mantgem Phillip J. van , Stephenson Nathan L
Published: December 2004

We assess the potential of increment coring, a common method for measuring tree ages and growth, to contribute to mortality. We used up to 21 years of annual censuses from two cored and two uncored permanent plots in the Sierra Nevada of California, to detect changes in mortality rates 12 years following coring for individuals >5 cm DBH from two coniferous species, Abies concolor (Gordon & Glend.) Lindl. (white fir) and Abies magnifica A. Murr. (red fir). Using a randomized before-after control impact (BACI) design, we found no differences in mortality rates following coring for 825 cored and 525 uncored A. concolor and 104 cored and 66 uncored A. magnifica. These results support the view that collecting tree cores can be considered nondestructive sampling, but we emphasize that our 12-year postcoring records are short compared with the maximum life-span of these trees and that other species in different environments may prove to be more sensitive to coring.
COMPARATIVE STUDY OF Ta AND TaN(N) IN THE BARRIER/ULTRA LOW k STRUCTURES FOR DEEP SUBMICRON INTEGRATED CIRCUITS
Authors: YANG L. Y. , ZHANG D. H. , LI C. Y. , LIU R. , WEE A. T. S. , FOO P. D.
Published: December 2004

Two kinds of barrier layers, Ta and TaN , deposited on an ultra low k dielectric porous polymer film with k=2.3 were evaluated using various techniques after thermal treatments at 400°C for different periods of time. It was found that the sheet resistance of the Ta barrier increased significantly after being annealed for 60 min while that of TaN increased after 120 min due to Ta-O compound formation as revealed by X-ray diffraction and secondary ion mass spectrometry. The better integrity of the TaN compared Ta is due to N incorporation, which limits the diffusion of Ta and O . The diffusion coefficient of Ta in the porous polymer is 0.023±0.001 nm 2/ s , while the diffusion coefficient of TaN is only 0.0033±0.0001 nm 2/ s .
EFFECT OF SINTERING CONDITIONS ON MAGNETIC PROPERTIES OF NANOPARTICLE Mn–Zn FERRITE SYNTHESIZED WITH NITRILOTRIACETATE PRECURSOR METHOD
Authors: TANGSALI R. B. , KELUSKAR S. H. , NAIK G. K. , BUDKULEY J. S.
Published: December 2004

Nitrilotriacetate precursors have been used for synthesis of oxide materials. High permeability Mn – Zn ferrite with general formula Mn x Zn 1-x Fe 2 O 4 where x=0.3/0.35/0.4/0.45/0.5/0.55/0.6/0.65/0.7 were prepared using this novel method. Formation of cubic spinel structure was confirmed by XRD, which also provided information on formation of fine particle material. The magnetic properties of these materials were investigated after sintering the same at 950°C, 1150°C, 1250°C and 1350°C in nitrogen atmosphere and at 1050°C in air and were found to be interesting.
COMPUTATIONAL STUDY OF TERNARY ALLOY NANOCLUSTER COMPOSITIONAL STRUCTURES: Ni–Cu–Rh VERSUS Ni–Cu–Pd
Authors: POLAK M. , RUBINOVICH L.
Published: December 2004

The Free-energy Concentration Expansion Method (FCEM) was utilized for the prediction of compositional structures in Ni – Cu – Rh cubo-octahedron nanoclusters in comparison to recently reported Ni – Cu – Pd data. While both systems exhibit site-specific, sequentially competitive surface segregation (and resultant core separations), remarkable differences governed by the opposite heteronuclear effective interactions, were noted in the surface compositional patterns. Thus, at relatively low temperatures "mixed" Cu/Pd ordering takes place at the Ni – Cu – Pd cluster surface, whereas in the Ni – Cu – Rh cluster Cu and Ni populate separate low and high-coordinated surface sites, thus forming a kind of "demixed surface order". Dissimilarities in the temperature dependence are discussed in terms of the interplay of segregation and compositional order. Such findings may have implications in heterogeneous catalysis and other technologies based on highly dispersed alloyed particles.
Recent Events in Alcoholic Liver Disease V. Effects of ethanol on liver regeneration
Authors: Diehl Anna Mae
Published: December 2004

Liver regeneration is necessary to recover from alcoholic liver injury. Herein, we review evidence that ethanol interferes with liver regeneration. Briefly, alcoholic fatty livers demonstrate increased rates of hepatocyte death. The latter provides a regenerative stimulus. However, unlike mature hepatocytes in healthy adult livers, most surviving mature hepatocytes in alcoholic fatty livers cannot replicate. Therefore, less mature cells (progenitors) must differentiate to replace dead hepatocytes. Little is known about the general mechanisms that modulate the differentiation of liver progenitors in adults. Delineation of these mechanisms and clarification of how ethanol influences them might suggest new therapies for alcoholic liver disease.
Reservoir and conduit function of right atrium: impact on right ventricular filling and cardiac output
Authors: Gaynor Sydney L. , Maniar Hersh S. , Prasad Sunil M. , Steendijk Paul , Moon Marc R.
Published: December 2004

The purpose of this study was to investigate the relationship between right atrial (RA) reservoir and conduit function and to determine how hemodynamic changes influence this relationship and its impact on cardiac output. In 11 open-chest sheep, RA reservoir and conduit function were quantified as RA inflow with the tricuspid valve closed versus open, respectively. Conduit function was separated into early (before A wave) and late (after A wave) components. The effects of inotropic stimulation, partial pulmonary artery occlusion, and pericardiotomy were tested. At baseline with the pericardium intact, reservoir function accounted for 0.56 (SD 0.13) of RA inflow, early conduit for 0.29 (SD 0.07), and late conduit (during RA contraction) for 0.16 (SD 0.11). Inotropic stimulation decreased conduit function and increased reservoir function, but these effects did not reach statistical significance. With partial pulmonary artery occlusion, early conduit function fell to 0.20 (SD 0.11) ( P < 0.04), and the conduit-to-reservoir ratio decreased by 41% ( P < 0.03). Similarly, after pericardiotomy, early conduit function fell to 0.14 (SD 0.09) ( P < 0.004), reservoir function increased to 0.72 (SD 0.08) ( P < 0.04), and, consequently, the early conduit-to-reservoir ratio decreased by 63% ( P < 0.006). Cardiac output was inversely related to the conduit-to-reservoir ratio ( r = 0.39, P < 0.001). This study demonstrated that the right atrium adjusts its ability to act more as a reservoir than a conduit in a dynamic manner. The RA conduit-to-reservoir ratio was directly related to the right ventricular pressure-RA pressure gradient at the time of maximum RA volume, with increased ventricular pressures favoring conduit function, but it was inversely related to cardiac output, with an increase in the reservoir contribution favoring improved cardiac output.
Protective role of mast cells in homocysteine-induced cardiac remodeling
Authors: Joseph Jacob , Kennedy Richard H. , Devi Sulochana , Wang Junru , Joseph Lija , Hauer-Jensen Martin
Published: December 2004

Recent reports including those from our laboratories indicate that hyperhomocysteinemia (Hhe) is an independent risk factor for cardiac dysfunction and clinical heart failure. Mast cell accumulation is a prominent feature in our model of Hhe-induced cardiac dysfunction. Because mast cell-derived mediators can potentially attenuate cardiac remodeling, we investigated the possible protective role of mast cells in Hhe-induced cardiac remodeling using a mast cell-deficient rat model that in our recent report did not demonstrate any adverse cardiac function at younger age (6 mo) than mast cell-competent control animals. Mast cell-deficient ( Ws/Ws) rats and mast cell-competent (+/+) littermate control animals (3 mo of age) were treated with a Hhe-inducing diet for 10 wk. Cardiac remodeling was assessed structurally utilizing histomorphometric methods and functionally using an isolated Langendorff-perfused heart preparation. The Hhe-inducing diet caused similar elevations of homocysteine levels in the two groups. Compared with Hhe +/+ rats, the Hhe Ws/Ws rats demonstrated strikingly exacerbated adverse cardiac remodeling and myocardial fibrosis. Cardiac function measurement showed worsened diastolic function in Hhe Ws/Ws rats compared with Hhe +/+ rats. The absence of mast cells strikingly exacerbates Hhe-induced adverse cardiac remodeling and diastolic dysfunction. These findings indicate a potential dual rather than sole deleterious role for mast cells in cardiac injury.
Effect of C-reactive protein on gene expression in vascular endothelial cells
Authors: Wang Qingwei , Zhu Xiaojun , Xu Qin , Ding Xia , Chen Yuqing E. , Song Qing
Published: December 2004

C-reactive protein (CRP) is significantly associated with the risk of ischemic cardiovascular disease in epidemiological studies. To explore if CRP has a functional role, we investigated its effect on the gene expression profile of vascular endothelial cells. Human vascular endothelial cells (human umbilical vein endothelial cells and human aortic endothelial cells) were incubated with CRP at various concentrations (0–10 μg/ml). Microarray analysis showed that a total of 11 genes increased (IL-8, core promoter element binding protein, activin A, monocyte chemoattractant protein 1, Exostoses 1, Cbp/p300-interacting transactivator with Glu/Asp-rich COOH-terminal domain 2, plasminogen activator inhibitor 1, fibronectin-1, gravin, connexin43, and sortilin-related receptor-1) and 6 genes decreased (methionine adenosyltransferase 2A, tryptophan-rich basic protein, reticulocalbin 1, membrane-associated RING-CH protein VI, cytoplasmic dynein1, and annexin A1) by more than twofold for their mRNA levels. IL-8 was the most significantly upregulated gene (13.6-fold), which demonstrated a clear dose- and time-dependent pattern revealed by quantitative real-time PCR. Cell adhesion assay showed that CRP enhanced the monocyte adhesion to endothelial cell monolayer by 2-fold ( P < 0.01), which was partially blocked by an anti-IL-8 antibody (34.2% inhibition, P < 0.01). Inhibition of ERK MAPK pathway using U0126 prevented CRP-induced IL-8 upregulation, and Western blot analysis revealed a rapid activation of ERK1/2 after CRP stimulation. These data showed that CRP can significantly influence gene expressions in vascular endothelium. The CRP-responsive genes suggested that CRP may have a broad functional role in cell growth and differentiation, vascular remodeling and solid tumor development.
Molecular properties of cardiac tail-anchored membrane protein SLMAP are consistent with structural role in arrangement of excitation-contraction coupling apparatus
Authors: Guzzo Rosa M. , Salih Maysoon , Moore Edwin D. , Tuana Balwant S.
Published: December 2004

The spatial arrangement of the cell-surface membranes (sarcolemma and transverse tubules) and internal membranes of the sarcoplasmic reticulum relative to the myofibril is critical for effective excitation-contraction (E-C) coupling in cardiac myocytes; however, the molecular determinants of this order remain to be defined. Here, we ascribe molecular and cellular properties to the coiled-coil, tail-anchored sarcolemmal membrane-associated protein (SLMAP) that are consistent with a potential role in organizing the E-C coupling apparatus of the cardiomyocyte. The expression of SLMAP was developmentally regulated and its localization was distinctly apparent at the level of the membranes involved in regulating the E-C coupling mechanism. Several SLMAP isoforms were expressed in the cardiac myocyte with unique COOH-terminal membrane anchors that could target this molecule to distinct subcellular membranes. Protein interaction analysis indicated that SLMAPs could self assemble and bind myosin in cardiac muscle. The cardiac-specific expression of SLMAP isoforms that can be targeted to distinct subcellular membranes, self assemble, and interact with the myofibril suggests a potential role for this molecule in the structural arrangement of the E-C coupling apparatus.
Is Cerebrospinal Fluid Spectrophotometry Useful in CT Scan-Negative Suspected Subarachnoid Haemorrage?
Authors: Gunawardena H. , Beetham R. , Scolding N. , Lhatoo S.D.
Published: December 2004

Missed cerebral aneurysms in CT-negative patients can have serious implications. We set out to determine the usefulness of cerebrospinal fluid (CSF) spectrophotometry and the individual significance of CSF oxyhaemoglobin, bilirubin and methaemoglobin in 463 CT scan-negative patients with suspected subarachnoid haemorrhage (SAH) and normal neurological examination. CSF spectrophotometry resulted in the diagnosis of an intracranial aneurysm in 2% (9/463) of patients with CT-negative suspected SAH. No aneurysms were found in patients in whom spectrophotometry was negative for haem pigments. Less than 1% of patients with oxyhaemoglobin alone had aneurysms diagnosed, whilst 21% of patients with bilirubin had an aneurysm. CSF spectrophotometry is an important investigation in patients with CT-negative suspected SAH, particularly where clinical suspicion is strong. Patients positive for bilirubin are likely to provide a high yield of aneurysmal bleed and should undergo angiography. Patients with oxyhaemoglobin alone in whom SAH is strongly suspected may benefit from angiography. Based on a small number of patients, we recommend that patients with methaemoglobin should also be investigated. Patients with negative spectrophotometry are unlikely to benefit from further investigation.
Steroid Therapy Altered Serum Levels of CCL2 and CCL5 Chemokines in Multiple Sclerosis Patients during Relapse
Authors: Bartosik-Psujek Halina , Stelmasiak Zbigniew
Published: December 2004

Chemokines are involved in the pathogenesis of multiple sclerosis. The aim of this study was to determine the impact of steroid therapy on the levels of CCL2 and CCL5 chemokines. The study encompassed 30 patients with clinically definite relapsing-remitting multiple sclerosis who were treated with methylprednisolone due to the relapse of the disease. The control groups consisted of 20 patients during the stable stage of relapsing-remitting multiple sclerosis and of 15 patients with noninflammatory diseases of the nervous system. Both chemokines were markedly expresssed in serum by enzyme-linked immunosorbent assay. During relapse, the levels of both chemokines differed significantly from the levels measured in both control groups. After the methylprednisolone treatment, the chemokine levels changed significantly: the levels of CCL2 increased, whilst the levels of CCL5 decreased. These alterations did not correlate with the clinical state of the patients or with the therapeutic effect of the treatment and indicated that the inflammatory reaction accompanying the relapse was receding.
Can a Commercial Diagnostic Ultrasound Device Accelerate Thrombolysis?
Authors: Pfaffenberger Stefan , Devcic-Kuhar Branka , Kollmann Christian , Kastl Stefan P. , Kaun Christoph , Speidl Walter S. , Weiss Thomas W. , Demyanets Svitlana , Ullrich Robert , Sochor Heinz , Wöber Christian , Zeitlhofer Josef , Huber Kurt , Gröschl Martin , Benes Ewald , Maurer Gerald , Wojta Johann , Gottsauner-Wolf Michael
Published: December 2004

Background and Purpose—

Recently, 3 clinical trials revealed encouraging results in recanalization and clinical outcome in acute stroke patients when 2-MHz transcranial Doppler monitoring was applied. This study investigated whether a 1.8-MHz commercial diagnostic ultrasound device has the potential to facilitate thrombolysis using an in vitro stroke model.

Methods—

Duplex-Doppler, continuous wave-Doppler, and pulsed wave (PW)-Doppler were compared on their impact on recombinant tissue plasminogen activator (rtPA)–mediated thrombolysis. Blood clots were transtemporally sonicated in a human stroke model. Furthermore, ultrasound attenuation of 5 temporal bones of different thickness was determined.

Results—

In comparison, only PW-Doppler accelerated rtPA–mediated thrombolysis significantly. Without temporal bone, PW-Doppler plus rtPA showed a significant enhancement in relative clot weight loss of 23.7% when compared with clots treated with rtPA only (33.9±5.5% versus 27.4±5.2%;
P
<0.0005). Ultrasound attenuation measurements revealed decreases of the output intensity of 86.8% (8.8 dB) up to 99.2% (21.2 dB), depending on temporal bone thickness (1.91 to 5.01 mm).

Conclusion—

Without temporal bone, PW-Doppler significantly enhanced thrombolysis. However, because of a high attenuation of ultrasound by temporal bone, no thrombolytic effect was observed in our in vitro model, although Doppler imaging through the same temporal bone was still possible.
A Challenge to Earthquake Engineering Professionals
Authors: Comartin Craig , Brzev Svetlana , Naeim Farzad , Greene Marjorie , Blondet Marcial , Cherry Sheldon , D'Ayala Dina , Farsi Mohammed , Jain Sudhir K. , Pantelic Jelena , Samant Laura , Sassu Mauro
Published: December 2004

Recent earthquakes have caused unacceptably high death tolls. We, the editors of the World Housing Encyclopedia, believe that reducing such an unacceptably high loss of life from earthquakes is the most important challenge facing the global earthquake engineering community. This paper acknowledges the continuing disparity between life loss from earthquakes in developing and developed countries, and the increasing vulnerability in developing countries. A sampling of current efforts to improve construction practices includes the publication of earthquake tips in India, construction manuals in Colombia, and the formation of various international networks to promote collaboration and information sharing. Future possibilities include more rewards for research into inadequately engineered construction, greater emphasis on small-scale, local efforts, and a stronger emphasis on advocacy. We believe that all of us, as earthquake professionals, have a responsibility to make the built environment safer worldwide.
Inelastic Seismic Response of Extended Pile-Shaft-Supported Bridge Structures
Authors: Hutchinson T. C. , Chai Y. H. , Boulanger R. W. , Idriss I. M.
Published: December 2004

Nonlinear static and dynamic analyses were used to evaluate the inelastic seismic response of bridge and viaduct structures supported on extended cast-in-drilled-hole (CIDH) pile shafts. The nonlinear dynamic analyses used a beam-on-nonlinear-Winkler foundation (BNWF) framework to model the soil-pile interaction, nonlinear fiber beam-column elements to model the reinforced concrete sections, and one-dimensional site response analyses for the free-field soil profile response. The study included consideration of ground motion characteristics, site response, lateral soil resistance, structural parameters, geometric nonlinearity (P-Δ effects), and performance measures. Results described herein focus on how the ground motion characteristics and variations in structural configurations affect the performance measures important for evaluating the inelastic seismic response of these structures. Presented results focus on a representative dense soil profile and thus are not widely applicable to dramatically different soil sites.
Protein-Protein Interactions and Transcriptional Antagonism between the Subfamily of NGFI-B/Nur77 Orphan Nuclear Receptors and Glucocorticoid Receptor
Authors: Martens Christine , Bilodeau Steve , Maira Mario , Gauthier Yves , Drouin Jacques
Published: December 2004

Glucocorticoids (Gc) act through the glucocorticoid receptor (GR) to enhance or repress transcription of glucocorticoid-responsive genes depending on the promoter and cellular context. Repression of proopiomelanocortin (POMC) gene expression by Gc was proposed to use different mechanisms. We described the POMC promoter Nur response element (NurRE) as a target for Gc repression. NGFI-B (Nur77), an orphan nuclear receptor, and two related factors, Nurr1 and NOR1, bind the NurRE as homo- or heterodimers to enhance POMC gene expression in response to CRH. Gc antagonize CRH-stimulated as well as NGFI-B-dependent transcription. We now show that GR antagonizes NurRE-dependent transcription induced by all members of the Nur77 subfamily and that these nuclear receptors can all interact directly with GR. Transcriptional antagonism as well as direct protein-protein interaction between NGFI-B and GR take place primarily via their respective DNA binding domains, although DNA binding itself and the GR homodimerization interface are not involved. In vivo, GR and Nur factors can be coimmunoprecipitated whereas GR is recruited to the POMC promoter upon glucocorticoid action. Thus, our data suggest a mechanism for transrepression between two nuclear receptors, GR and NGFI-B, that is unique, although quite similar to that proposed for transrepression between GR and activator protein 1 (AP-1) or nuclear factor-κB (NFκB).
Synthesis of Carbon Nanotube Composites in Nanochannels of an Anodic Aluminum Oxide Film
Authors: Kyotani Takashi , Pradhan Bhabendra Kumar , Tomita Akira
Published: December 2004

A template carbonization technique was applied for synthesizing carbon nanotubes and metal filled nanotubes. An anodic aluminum oxide film that has uniform and straight channels with a diameter at nanometer level was used as a one-dimensional template. The pyrolytic carbon deposition on the channel wall was carried out by exposing the anodic oxide film to hydrocarbon gas at high temperature. The carbon was then liberated from the anodic oxide film by dissolving the alumina template. It was found that the resultant carbon is comprised only of uniform hollow-tubes with open ends. The length and the diameter of the carbon nanotubes are controllable by changing the length and the inner diameter of the channels in the anodic oxide film. By applying this template technique, metal filled uniform carbon nanotubes can also be fabricated. Pt, Ag, and Fe-filled carbon nanotubes were synthesized. If one varies metal the loading and metal reduction methods, various shapes of nano metal compounds can be inserted into the hollow of carbon nanotubes. It should be noted that no metal was observed on the outside walls of the tubes. The metal-filled uniform carbon nanotube thus prepared can be regarded as a novel one-dimensional composite, which has a variety of potential applications.
Hexadecylpyridinium Chloride + Trimethyltetradecylammonium Bromide Mixed Micelles in Polyethylene Glycol + Water Mixtures
Authors: Bakshi Mandeep Singh , Doe Hidekazu
Published: December 2004

The conductances of hexadecylpyridinium chloride (HPyCl) + trimethyltetradecylammonium bromide (TTAB) mixtures over the entire mole fraction range of HPyCl (αHPyCl) were measured in aqueous binary mixtures of polyethylene glycol (PEG) 200, 400, 600, and 4000 containing different amounts of each PEG in their respective binary mixtures at 30 °C. Each conductivity curve showed a single break, except in the presence of PEG 4000 where two breaks were observed. From the conductivity (κ) data, the critical micellar concentration (cmc), degree of counter ion association (χ), the equivalent conductivities (Λ) from the slope of κ versus C plots, and the standard Gibb’s free energy of transfer of the surfactant hydrocarbon chain from the medium to the interior of the micelle (ΔGHP°) were computed. It was observed that micelle–PEG interactions in the case of HPyCl and TTAB were quite similar to mixed micelle–PEG interactions especially in the presence of PEG 200, 400, and 600. The results were explained on the basis of medium structure-breaking effects of PEG and adsorption of PEG on the micelle–solution interface. In the presence of PEG 4000, the micelle formation corresponding to the first break was found to be similar to that in the presence of PEG 200, 400, and 600. The second break was designated to the polymer bound micellar aggregates, which became more stable as the amount of PEG 4000 was increased.
1H, 2H, 19F, 31P, and 35Cl NMR Studies on Molecular Motions in Ionic Plastic Phases of Pyrrolidinium Perchlorate and Hexafluorophosphate
Authors: Ono Hiroshi , Ishimaru Shin’ichi , Ikeda Ryuichi , Ishida Hiroyuki
Published: December 2004

Measurements of 1H, 2H, 19F, 31P, and 35Cl NMR, differential scanning calorimetry (DSC), and X-ray powder diffraction were carried out in solid pyrrolidinium perchlorate ([C4H8NH2]ClO4) and hexafluorophosphate ([C4H8NH2]PF6). Five and three solid phases were obtained in perchlorate and hexafluorophosphate, respectively, by DSC measurement above 150 K. X-Ray powder patterns showed the highest-temperature solid phase of both salts to be CsCl-type cubic, indicating that both cations and anions take isotropically disordered orientations. The measurements of the NMR linewidth and its second moment revealed that the C4H8NH2+ and PF6− ions perform self-diffusion as well as isotropic rotation in this phase. From the dynamical behaviour of ions, the highest-temperature phase can be assigned to be an ionic plastic phase; this is the first example of an ionic plastic phase containing pyrrolidinium cations.
Electrocatalysis of O2 Reduction at Glassy Carbon Electrodes Modified with Adsorbed 1,4-Dihydroxy-9,10-anthraquinone Derivatives
Authors: Salimi Abdollah , Mousavi Mir Fazlollah , Sharghi Hashem , Shamsipur Mojtaba
Published: December 2004

The preparation and electrochemical characterization of glassy carbon electrodes modified by four recently synthesized 1,4-dihydroxy-9,10-anthraquinone derivatives are reported. The anthraquinones used were strongly and irreversibly adsorbed on the preanodized glassy carbon electrodes. The electrochemical behavior and stability of the modified electrodes were studied by cyclic voltammetry at different acidic and basic aqueous solutions, and pH of 6—7 was chosen as the optimum working pH. The adsorbed anthraquinone derivatives showed excellent electrocatalytic ability for the reduction of O2 to H2O2 with overpotentials of from 560 to 650 mV lower than that of a plain glassy carbon electrode. The heterogeneous rate constants for the reduction of O2 at the surface of the modified electrodes were determined by rotating-disk electrode voltammetry using the Koutecky–Levich plots. The apparent diffusion coefficient of O2 in buffered aqueous O2-saturated solutions was also estimated.
Recent Advances in the Synthesis of trans-Fused Polycyclic Ethers by Hydroxy-Epoxide-Cyclization and Ether-Ring-Expansion Reactions
Authors: Fujiwara Kenshu , Murai Akio
Published: December 2004

Natural trans-fused polycyclic ethers, produced by marine sources such as dinoflagellates, are hypothesized to be constructed efficiently from the corresponding polyepoxide precursors by a cascade of ring-closure reactions. The efficiency of the biogenetic pathway has been attractive for synthetic chemists and has prompted them to develop new methods for the construction of cyclic ethers from epoxides. In this review, recent advances in the synthesis of trans-fused polycyclic ethers by hydroxy-epoxide-cyclization reactions via monocyclic epoxonium ion intermediates and ether-ring-expansion reactions via bicyclic epoxonium ion intermediates are described.
A Non-Born–Oppenheimer Effective Hamiltonian for the Analysis of Vibrational–Rotational and Rotational Spectra of Diatomic Molecules
Authors: Uehara Hiromichi
Published: December 2004

A non-Born–Oppenheimer effective Hamiltonian for diatomic molecules with optimal fitting parameters, i.e., determinable clusters of expansion coefficients of Born–Oppenheimer corrections, has been derived. The effective Hamiltonian has formally the same form as Dunham’s Hamiltonian, except for additional corrections for successive ξ′i terms of a series expansion of the rotational parameter B(ξ′), extending the determinacy of the optimal parameters, ΔBa,b, Δωa,b, Δaiqa,b, riqa,b, in general for i = 1, 2, 3, ..., if spectra of isotopomers of atoms A and B are analyzed simultaneously. The effective Hamiltonian provides a clear-cut understanding of determinable correction parameters; e.g., in Dunham-type potential fits to spectral transitions for the single isotopomer optimal parameters δriq (i = 1, 2, ...) for corrections of series expansion terms of B(ξ′) should explicitly be included. The physical significance of the optimal parameters as well as of conventional molecular parameters, Be, −De, He, ωe, and −αe, etc., is described.
Photocatalytic Oxidation of Alkanes with Dioxygen by Visible Light and Copper(II) and Iron(III) Chlorides: Preference Oxidation of Alkanes over Alcohols and Ketones
Authors: Takaki Ken , Yamamoto Jun , Komeyama Kimihiro , Kawabata Tomonori , Takehira Katsuomi
Published: December 2004

Visible light irradiation of alkanes in acetonitrile with CuCl2 and FeCl3 catalysts under atmospheric dioxygen gave the corresponding alcohols and ketones effectively; in these reactions, the total selectivity of the products did not decrease so much with increase of alkane conversion. For example, cyclohexanol and cyclohexanone were formed with ca. 70% selectivity at 50% conversion, because overoxidation of the products took place more slowly than cyclohexane oxidation. The relative reactivity values of cycloalkanes increased as their ring-sizes decreased. In the oxidation of hexane, the reactivity ratio of C1-/C2-/C3-H was found to be 1.0/1.4/1.8 with CuCl2 and 1.0/4.6/6.6 with FeCl3, respectively. Toluene and diphenylmethane were more reactive than cyclohexane with FeCl3, as expected, whereas the alkane was oxidized faster than the benzylic compounds in the separate reaction with CuCl2. Moreover, the alkane oxidation could be comparably performed by sunlight instead of an artificial lamp.
p-Type Semiconductors of Aromatic Diamines Doped with SbCl5
Authors: Ganzorig Chimed , Suga Kosaku , Fujihira Masamichi
Published: December 2004

Doping of N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD) with antimony pentachloride (SbCl5) as a method to form its p-type organic semiconductor material is described. UV–visible absorption and X-ray photoelectron spectroscopic (XPS) data indicated formation of radial cations and dications in TPD films doped with SbCl5. This doping played important roles in hole conduction and in hole injection from an indium-tin oxide (ITO) electrode to the doped TPD layer in typical electroluminescent (EL) organic thin film devices.
New Hole-Transporting Amorphous Molecular Materials with High Glass-Transition Temperatures for Organic Light-Emitting Diodes
Authors: Okumoto Kenji , Shirota Yasuhiko
Published: December 2004

New hole-transporting amorphous molecular materials with high glass-transition temperatures (Tgs), 4,4′,4″-tris[9,9-dimethyl-2-fluorenyl(phenyl)amino]triphenylamine (TFATA) and N,N,N′,N′-tetrakis(9,9-dimethyl-2-fluorenyl)-[1,1′-biphenyl]-4,4′-diamine (FFD), have been developed. TFATA and FFD exhibit hole drift mobilities of 1.7 × 10−5 and 4.1 × 10−3 cm2V−1s−1, respectively, at 293 K at an electric-field of 1.0 × 105 Vcm−1 in their amorphous glasses. These materials permit the fabrication of thermally stable, high-performance organic light emitting diodes.
Oxidative Arylation of Ethylene with Benzene to Produce Styrene
Authors: Matsumoto Takaya , Yoshida Hajime
Published: December 2004

Rh complexes were found to work as catalysts for oxidative arylation of ethylene with benzene to produce styrene by addition of acetylacetone and O2 without any oxidizing agent like Cu salt. Vinylacetate was not formed at all in spite of coexistence of acetic acid.
Thermodynamic Consequences of Single-mutation on Association of an Antibody with Its Specific Antigen: The Case of HyHEL-10-hen Lysozyme Complex
Authors: Tsumoto Kouhei , Kumagai Izumi
Published: December 2004

The interactions between protein antigen and its specific antibodies with one-point mutation have been investigated using isothermal titration calorimetry. Some mutation led to the increase in enthalpy change, and others to the decrease. Contributions of each amino acid to the interaction could be classified with two types, i.e., enthalpic and entropic.
Novel Non-benzenoid Electron Acceptors: Syntheses and Electron Acceptability of Tetracyanoazulenequinodimethanes and Dicyanoazulenequinonemethides
Authors: Sato Ohki , Koizumi Yosuke , Sekiguchi Yoshihiro , Yoshioka Sachiko , Tsunetsugu Josuke , Yan Yong Zhe , Mori Akira , Takeshita Hitoshi , Nozoe Tetsuo
Published: December 2004

Tetracyanoazulenequinodimethanes and dicyanoazulenequinonemethides, a new family of azulene-based electron acceptors have been derived from mono-, di-, and tri-bromo- and -chloro-azulenequinones by reaction with titanium tetrachloride, malononitrile and pyridine. Their unique electron acceptability has been revealed by CV measurement.
Active Species of Molybdenum Carbide Catalysts in Methane Reforming: η-Mo3C2
Authors: Oshikawa Katsuhiko , Nagai Masatoshi , Omi Shinzo
Published: December 2004

η-Mo3C2 was the most active molybdenum carbide species for methane reforming, surpassing β-Mo2C which has been reported previously. From the correlation of the TPR results, the amount of η-Mo3C2 was directly related to the methane decomposition rate, indicating the importance of this type of carbide for methane reforming.
Triplet State of O-Acyloximes Studied by Time-Resolved Absorption Spectroscopy
Authors: Allonas Xavier , Lalevée Jacques , Fouassier Jean-Pierre , Tachi Hideki , Shirai Masamitsu , Tsunooka Masahiro
Published: December 2004

Triplet states of O-acyloximes were studied for the first time by means of laser absorption spectroscopy. Energy transfer experiments showed that the acyl moiety has no effect on the triplet energy, which depends only on the ketone oxime part. It was observed that the difference between the triplet energy of the parent ketone and that of the oxime varies, depending on the oxime structure. This behaviour is explained on the basis of a non-vertical character of the energy transfer reaction.
Oxidized Diamond: A Novel Support for Catalytic Dehydrogenation
Authors: Nakagawa Kiyoharu , Kajita Chiaki , Ikenaga Na-oki , Kobayashi Tetsuhiko , Nishitani-Gamo Mikka , Ando Toshihiro , Suzuki Toshimitsu
Published: December 2004

We found that oxidized diamond played a significant role to improve catalyst performance of Cr2O3 catalyst during the dehydrogenation of C2H6 to C2H4 in the presence of CO2.
Catalytic Asymmetric Borane Reduction of Prochiral Ketones by the Use of Chiral β-Diamines
Authors: Asami Masatoshi , Sato Shinsuke , Watanabe Hiroyasu
Published: December 2004

The catalytic asymmetric borane reduction of prochiral ketones was examined in the presence of chiral β-diamines. Chiral secondary alcohols were obtained with modest to high enantiomeric excesses (up to 92% ee) using (S)-2-[(p-trifluoromethyl)anilinomethyl]indoline.
High Catalytic Activity of As-Synthesized, Ordered Porous Silicate–Quaternary Ammonium Composite for Knoevenagel Condensation
Authors: Kubota Yoshihiro , Nishizaki Yusuke , Sugi Yoshihiro
Published: December 2004

The Knoevenagel condensation of carbonyl compounds with active methylene compounds catalyzed by as-synthesized, ordered porous silicate–quaternary ammonium composite materials gave corresponding α,β-unsaturated esters in high yields under very mild liquid phase conditions.
Thermodynamics and solubility of (U
x
Np1-

x
)O2(am) solid solution in the carbonate system
Authors: Rai Dhanpat , Hess Nancy J. , Yui M. , Felmy Andrew R. , Moore D. A.
Published: December 2004

The formation of a solid solution can significantly affect the solubility of a minor component. The objectives of this study were to determine the nature of U(IV) and Np(IV) solid solutions and their thermodynamic properties. For this purpose, (U
x
Np1-

x
)O2(am) precipitates with values of x varying from 0.05 to 0.95 were prepared, characterized, and used to determine their solubility in dilute to concentrated K2CO3 and KHCO3 solutions. The solubility data show that the equilibrium in these systems is reached in < 7 days, the solubility-controlling solids are amorphous, and that we were successful in maintaining U and Np in the tetravalent state. A scanning electron microscope equipped with energy dispersive spectrometry and X-ray absorption spectroscopic analyses of the solids indicated the quilibrated co-precipitates to be solid solutions. A close agreement between the thermodynamic predictions, assuming an ideal solid solution, and the experimental solubilities shows that U(IV) and Np(IV) form an ideal solid solution and that non-ideal solid solution behavior for this system can be ruled out.
Modeling of the complex formation of metal ions with humic acids
Authors: Tochiyama Osamu , Niibori Yuichi , Tanaka Kouichi , Kubota Takumi , Yoshino Hirofumi , Kirishima Akira , Setiawan Budi
Published: December 2004

Based on the conceptual model of cation-humic interactions considering the heterogeneous composition and polyelectrolyte nature of humic acids, the description of the interaction by the expression, logKapp= logK-mlog [M]+alogα-blog [Na+], is proposed, whereKapp=[M··(zR)]/([M][R]), [M··(zR)] is the concentration of the cation bound to the humic acid, [M] is the concentration of the free cation with charge z, and [R] is the concentration of the free anionic sites of the humic acid, [R]=(CR-z[M··(zR)])α(CRis a total concentration of proton exchanging sites and α is a degree of dissociation). logK,m,aandbare the constant parameters depending on the cation and the humic acid. The expression is successfully applied to the experimental results on the complex formation (or protonation) of humate and polyacrylate (a homogeneous polymeric weak acid) with H+, NpO2+, Eu3+, Ca2+, Fe2+and Fe3+obtained under the condition where hydrolysis of cations and saturation of the reacting sites can be neglected.
The reduction of U(VI) by near field hydrogen in the presence of UO2(s)
Authors: Spahiu Kastriot , Devoy Jerome , Cui Daqing , Lundström Max
Published: December 2004

In several recent works a large impact of dissolved hydrogen on spent fuel dissolution has been observed: the solution concentrations of all redox sensitive components of the spent fuel decrease with time, while gas phase analyses indicate levels of radiolytic oxygen below the detection limit. This indicates that at the relatively low temperatures of these studies (≤70 °C) hydrogen is activated. The aim of this study is to test one of the proposed mechanisms for hydrogen activation, namely by UO2(s) surfaces, which may act as hydrogen catalysts. Dissolved U(VI) carbonate species were used as oxidized species in order to test the reducing ability of hydrogen in the presence and absence of UO2(s). In most cases parallel experiments with the same conditions, but under Ar(g) atmosphere were carried out as blanks. Quartz lined autoclaves avoiding any contact of the solution with metallic parts were used. The experiments were carried out in two stages: first the stability of the (10-7-10-5) M U(VI) in 10 mM NaCl, 2 mM NaHCO3 solutions in the presence of dissolved hydrogen was tested. Then a gold net basket containing UO2(s) fragments was introduced in the autoclave and the concentration of U(VI) was followed at different time intervals by ICP-MS. Various dissolved hydrogen concentrations, temperatures and U(VI) concentrations were used, always spanning the range of these parameters in a proposed deep rock repository. Especially at the lowest U(VI) concentrations tested (∼100 ppb) the activation of dissolved hydrogen by UO2(s) surfaces is clearly visible. As a conclusion of this work it may be stated that in the temperature range (20-70 °C) investigated a) dissolved hydrogen does not reduce U(VI) carbonate species in the absence of a catalyst and b) in the presence of UO2(s) surfaces dissolved hydrogen reduces U(VI) in carbonate solutions, very probably to UO2(s).
The fate of radiolytic oxidants during spent fuel leaching in the presence of dissolved near field hydrogen
Authors: Spahiu Kastriot , Cui Daqing , Lundström Max
Published: December 2004

In most European disposal concepts, one expects large amounts of dissolved hydrogen produced by the anoxic corrosion of iron inside a damaged container. At repository temperatures (<100 °C), dissolved hydrogen is quite inert and is not expected to contribute to the redox capacity of the deep groundwaters. In a previous work from this laboratory we observed a large impact of dissolved hydrogen on the dissolution of the spent fuel in stainless steel autoclaves. In this work we report data on spent fuel dissolution obtained using quartz lined autoclaves to ensure that there is no contact between the solution and the metallic parts; we also made a number of other experimental improvements. The autoclave was filled with a solution 10 mM NaCl, 2 mM NaHCO3 and with H2+0.03% CO2 at a pressure of 0.5 MPa in the remaining free volume. The leaching of PWR spent fuel powder, placed in a gold basket, was studied during more than one year by analysing solution samples taken at regular time intervals. Special care was devoted to the study of the initial phase of the dissolution that was not investigated previously. In spite of the ten times lower hydrogen concentration as compared to the study in stainless steel autoclaves, extremely low concentrations of uranium (less than 10-9 M) were again measured in the solution samples; this was the case also for most of the redox sensitive fuel components. The uranium levels in solution remained practically constant during the whole leaching period, indicating the absence of any oxidative dissolution of the spent fuel matrix. In order to follow the fate of radiolytic oxidants, gas phase analyses were also carried out. The radiolytic oxygen levels in the autoclave measured after one year leaching were below the detection limit. A discussion of the fate of the radiolytic oxidants in these experiments and the mechanism of the hydrogen activation is also presented. The main conclusion is that for concentrations of dissolved hydrogen above 4 mM, no measurable oxidative dissolution of the UO2 matrix seems to occur in the studied systems.
Structural changes of uranyl moiety with reduction from U(VI) to U(V)
Authors: Mizuoka Koichiro , Ikeda Yasuhisa
Published: December 2004

Redox behavior of UVIO2(dbm)2DMSO (dbm = dibenzoylmethanate, DMSO = dimethyl sulfoxide, 2VI
) and structural properties of UVO2
+ complexes have been investigated with cyclic voltammetry and IR spectroelectrochemical technique, respectively. As a result, it was confirmed that 2VI
is quasi-reversibly reduced to [UVO2(dbm)2DMSO]- (2V
) without any successive reactions, and that 2V
is stable in DMSO. The formal potential for the redox couple, 2V
/2VI
, is -1.362 V vs . the ferrocene/ferrocenium ion redox couple. The IR spectra measured at various applied potentials show a shift of the peak due to the asymmetric stretching (ν3) of O=U=O from 906 to 775 cm-1 with the reduction from 2VI
to 2V
. From the ν3 peak positions, U=O distances of 2V
and 2VI
were estimated as 1.82 and 1.76 Å by Badger´s rule.
Uranium adsorption on weathered schist – intercomparison of modelling approaches
Authors: Payne Timothy E. , Davis James A. , Ochs Michael , Olin Markus , Tweed Cherry J.
Published: December 2004

Experimental data for uranium adsorption on a complex weathered rock were simulated by twelve modelling teams from eight countries using surface complexation (SC) models. This intercomparison was part of an international project to evaluate the present capabilities and limitations of SC models in representing sorption by geologic materials. The models were assessed in terms of their predictive ability, data requirements, number of optimised parameters, ability to simulate diverse chemical conditions and transferability to other substrates. A particular aim was to compare the generalised composite (GC) and component additivity (CA) approaches for modelling sorption by complex substrates. Both types of SC models showed a promising capability to simulate sorption data obtained across a range of chemical conditions. However, the models incorporated a wide variety of assumptions, particularly in terms of input parameters such as site densities and surface site types. Furthermore, the methods used to extrapolate the model simulations to different weathered rock samples collected at the same field site tended to be unsatisfactory. The outcome of this modelling exercise provides an overview of the present status of adsorption modelling in the context of radionuclide migration as practised in a number of countries worldwide.