bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐Field EPR Study of Frozen Aqueous Solutions of Iron(III) Citrate Complexes
Authors: Biaso Frédéric , Duboc Carole , Barbara Bernard , Serratrice Guy , Thomas Fabrice , Charapoff Denis , Béguin Claude 
Published: December 2004

AbstractHigh‐field electron paramagnetic resonance spectra have been measured for frozen aqueous solutions of FeIII citrate at acidic and neutral pH values. At high fields (up to 12 T) and high frequencies (95, 190 and 285 GHz), fine‐structure peaks due to resonance between Kramers doublets (±1/2, ±3/2, ±5/2) of an S = 5/2 species can be observed when the experiments are performed at high temperatures. A full‐matrix diagonalisation approach has been used to derive the spin‐Hamiltonian parameters for the S = 5/2 spin state. In acidic media (pH = 2), the spacing of the fine structure reveals that the value of the axial zero‐field splitting (ZFS) parameter D is −0.12 cm−1 without rhombicity. A small but significant g anisotropy can be observed which depends slightly on the frequency and the temperature (gx = 2.014, gy = 2.014 and gz = 1.983, at 60 K and 285 GHz). In neutral media (pH = 6), complete rhombic HF‐EPR spectra were observed with a fivefold lower |D| value (0.024 cm−1) and E = 0.008 cm−1. A satisfactory simulation of the experimental data was obtained with a g value equal to 2.00. The different ZFS parameters obtained under neutral and acidic conditions are discussed in terms of the symmetry of the complex. At low temperatures, a spin transition from 5/2 to 1/2 occurs at all frequencies. The transition temperature is pH‐ and field‐dependent. A model including magnetoelasticity has been suggested in order to interpret the field dependency of the spin transition observed for the two systems. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Anion and Solvent Effects upon the Structures of Platinum(II) Complexes with Thiacrown Ligands: The Crystal Structures of [Pt(9S3)2](PF6)2·2 CH3NO2, [Pt(9S3)2](BF4)2·2 CH3NO2, [Pt(9S3)2](OTf)2·2 CH3NO2, and [Pt(18S6)](BF4)2
Authors: Grant Gregory J. , Chen Weinan , Goforth Andrea M. , Baucom Clarilyn L. , Patel Ketankumar , Repovic Pavle , VanDerveer Donald G. , Pennington William T. 
Published: December 2004

AbstractThe synthesis and crystal structures of four mononuclear PtII homoleptic complexes with two thiacrown ligands are presented. The binding mode for both macrocycles to the platinum center contrasts with previous structural reports involving identical complex cations but differing anions or crystallization solvents. All three bis(1,4,7‐trithiacyclononane(9S3))platinum(II) complexes (with tetrafluoroborate, hexafluorophosphate, and triflate as counterions) are centrosymmetric, with endodentate binding of the trithioether resulting in [S4 + S2] coordination. The PtII complex of 1,4,7,10,13,16‐hexathiacyclooctadecane(18S6) shows an elongated square pyramidal structure with one exodentate sulfur in a [S4 + S1] mode. Our work illustrates how changes of counterion and solvent dramatically affect the crystal structures for such complexes, suggesting that packing forces are more important than ligand conformation in determining solid‐state structures. In addition, the full spectroscopic and electrochemical properties of the complex [Pt(18S6)](BF4)2 are reported. The electronic spectrum shows a d−d transition near 430 nm, and an irreversible PtII/PtIII couple occurs at +564 mV vs. Fc/Fc+ in cyclic voltammetry. Both these data are consistent with other hexakis(thioether) PtII complexes. 13C NMR measurements show a non‐fluxional 18S6 ligand in the complex while the platinum‐195 NMR resonance at −4152 ppm indicates a mixed orientation of lone pair electrons on the sulfur donors. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Causes of Nonplanarity in Fluorinated 1,3λ4δ2,2,4‐Benzodithiadiazines: Gas‐Phase Electron Diffraction, Ab initio and DFT Structures
Authors: Turner Andrew R. , Blockhuys Frank , Van Alsenoy Christian , Robertson Heather E. , Hinchley Sarah L. , Zibarev Andrey V. , Makarov Alexander Yu. , Rankin David W. H. 
Published: December 2004

AbstractThe gas‐phase molecular structures of 6,8‐difluoro‐1,3λ4δ2,2,4‐benzodithiadiazine and 5,6,7‐trifluoro‐1,3λ4δ2,2,4‐benzodithiadiazine have been determined using quantum chemical calculations and electron diffraction via the SARACEN method of structural analysis. Of particular interest was the planarity or nonplanarity of the heterocyclic fragments of the molecules. It was shown that the difluoro compound is planar with respect to the heterocyclic fragment [folding angle: 0.0(5)° (figures in parenthesis indicate e.s.d.s in the final digits)] and that the trifluoro compound probably deviates from planarity to a small extent [folding angle: 4.0(−30;+3)°; the large uncertainty in the value of this angle is due to the low‐frequency, large‐amplitude vibrational motion associated with the folding of the heterocyclic fragment]. Pertinent structural parameters from the electron diffraction data (rh1 structure) of the difluoro compound are av[r(S=N)] = 155.7(7) pm, r(S−N) = 175.8(5) pm, r(C−S) = 176.6(8) pm and r(C−N) = 141.6(2) pm. For the trifluoro compound the equivalent structural parameters are av[r(S=N)] = 155.5(7) pm, r(S−N) = 170.7(6) pm, r(C−S) = 180.6(8) pm and r(C−N) = 140.6(2) pm. The gas‐phase electron diffraction structures have been compared with results from ab initio and DFT calculations and also with experimental solid‐state structures. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
The status of life‐cycle assessment as an environmental management tool
Authors: Curran Mary Ann 
Published: December 2004

AbstractAs environmental awareness increases, industries and businesses have responded by providing “greener” products and using “greener” processes. Many companies have found it advantageous to explore ways of moving beyond compliance, using pollution prevention strategies and environmental management systems, to improve their environmental performance. One such way is life‐cycle assessment (LCA). This concept considers the entire life cycle of a product, process, or an activity. Evaluating environmental impacts holistically from raw material acquisition, through manufacture, use, and disposal using a life‐cycle perspective is gradually being viewed by environmental managers and decision makers as an important element in achieving environmental sustainability. The use of a holistic, life‐cycle approach can help industry and government avoid the unintended trading of one environmental problem for another. This paper addresses ongoing research in LCA methodology in the US EPA's National Risk Management Research Laboratory. Two key areas of this research include life‐cycle inventory (LCI) data availability and life‐cycle impact assessment (LCIA) modeling.To address the issue of data availability, EPA developed a website entitled LCAccess. Although LCAccess does not itself contain data, it is a searchable global directory to potential data sources. LCAccess also serves as a central source for LCA information. In addition, EPA developed TRACI (the Tool for the Reduction and Assessment of Chemical and other environmental Impacts), which allows the characterization of ozone depletion, global warming, acidification, eutrophication, tropospheric ozone (smog) formation, ecotoxicity, human particulate effects, human health, fossil fuel depletion, and land use effects. TRACI can be used with life‐cycle inventory to further analyze and understand the data. © 2004 American Institute of Chemical Engineers Environ Prog, 2004
The basidiomycete genus Polyporus – an emendation based on phylogeny and putative secondary structure of ribosomal RNA molecules
Authors: Krüger D. , Gargas A. 
Published: December 2004

AbstractThe fungal genus Polyporus is an assemblage of white‐rotting lignicolous basidiomycetes. It has undergone considerable expansion and contraction over a period of two and three quarter centuries. Current generic circumscription of Polyporus has kept the genus non‐monophyletic. Species of Polyporus infrageneric group Polyporellus are closely related to some species of Lentinus. We introduce data for ITS2 spacer rRNA secondary structure evolution by quasi‐independent comparison with large subunit rRNA phylogeny, and suggest a fraction of primary nuclear rDNA ITS sequence data as novel taxonomic character. A major taxonomic shift is suggested, supported by molecular and morphological characters, and allowing inclusion of species with gilled hymenophores in Polyporus. Two new names are proposed: Polyporus phyllostipes D.Krüger, nom. nov. and Polyporus gerdai D.Krüger, nom. nov. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Removal of phosphate by adsorption onto oyster shell powder—kinetic studies
Authors: Namasivayam C , Sakoda A , Suzuki M 
Published: December 2004

AbstractKinetic studies on the removal of phosphate by adsorption onto oyster shell powder have been investigated at 24 °C. The results showed that the equilibrium occurred in 10 min and the equilibrium data followed the Freundlich isotherm. Freundlich constants were found to be kf, 1.4 × 10−2, and n, 0.71. The phosphate removal was not influenced by pH over the range 5.0–10.5. Continuous agitation studies at 24 °C and 530 rpm reached equilibrium after 7.7 days, when 24 g dm−3 of oyster shell powder reduced the phosphate concentration from 50 to 7.0 mg dm−3. The Lagergren rate constant for the slow adsorption process was observed to be 3.81 × 10−4 dm3 min−1. Comparison with calcium carbonate, GR grade, showed that oyster shell powder and CaCO3 behave more or less in the same way. Copyright © 2004 Society of Chemical Industry
Altered intracellular sorting signals do not influence the efficacy of genetic melanoma vaccines incorporating helper determinants in mice
Authors: Brück Jürgen , Steitz Julia , Strand Dennis , Tüting Thomas 
Published: December 2004

AbstractBackgroundA genetic melanoma vaccine consisting of cDNA encoding the model self‐antigen tyrosinase‐related protein 2 (TRP2) fused in‐frame to the immunogenic enhanced green fluorescent protein (EGFP) was able to break immune tolerance and stimulate CD8+ T cells in vivo. In the present study we investigated whether alteration of the intracellular antigen localization as a result of the linkage with immune‐enhancing helper proteins affects the resulting immune response.MethodsExpression plasmids and recombinant adenoviruses were constructed encoding various fusion proteins with different intracellular sorting signals which direct the antigen to the cytosol, the endoplasmic reticulum or the endosomal compartments. Genetic immunization of C57BL/6 mice was performed with all constructs using particle‐bombardment of the skin and injection of recombinant adenoviruses. The resulting immune response was analyzed using ELISPOT and tumor rejection assays.ResultsInduction of TRP2‐specific CD8+ T cells in vivo and autoimmune‐mediated destruction of melanocytes in the bombarded area of the skin were observed with all constructs expressing fusion proteins between TRP2 and EGFP. Importantly, injections of the different recombinant adenoviruses all mediated protective immunity against transplanted B16 melanoma cells.ConclusionsAltered intracellular sorting signals do not significantly influence the efficacy of genetic melanoma vaccines incorporating helper determinants in our model system. These results further support the concept that linkage of immunogenic helper sequences can be successfully applied for antigen‐specific immunotherapy of melanoma and provide a scientific basis for the translation of this strategy in future clinical applications. Copyright © 2004 John Wiley & Sons, Ltd.
Short Portrait of Prof. Dr. Oskar Nuyken on the Occasion of his 65th Birthday
Authors: Voit Brigitte I. 
Published: December 2004

AbstractThis section contains news of the macromolecular community all over the world. Articles about, for example, people, projects, and market trends are welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de. The editorial office decides which articles will be published.
Analysis of the course of Parkinson's disease under dopaminergic therapy: Performance of “fast tapping” is not a suitable parameter
Authors: Kraus Peter H. , Klotz Peter , Hoffmann Arndt , Lewe Johannes , Przuntek Horst 
Published: December 2004

AbstractIn addition to clinical rating scales, instrumental methods are employed frequently for assessment of performance or motor deficits in Parkinson's disease (PD). Many studies have analyzed such parameters in cross‐sectional studies. We employed a battery of tests to investigate fine motor performance over a period of 4 years in 411 de novo parkinsonian patients from the Prado study. Specifically, tapping and pegboard testing (“plugging”) were evaluated and performance on these tests compared with clinical ratings. Plugging scores correlated well with tapping scores and clinical rating at each assessment timepoint. Both tests also showed significant differences to healthy controls. Nevertheless “fast tapping” was found to be less impaired than was plugging in de novo patients. Over time, it was observed that plugging scores, but not tapping scores, exhibited changes that paralleled movements in clinical score. Plugging scores exhibited a marked response to dopaminergic therapy whereas fast tapping showed no therapeutic response. Fast tapping is certainly not suitable for assessment of bradykinesia or hypokinesia, and does not respond to dopaminergic therapy. © 2004 Movement Disorder Society
Modelling and process optimization for functionally graded materials
Authors: Bellur‐Ramaswamy Ravi S. , Haber Robert , Sobh Nahil A. , Tortorelli Daniel A. 
Published: December 2004

AbstractWe optimize continuous quench process parameters to produce functionally graded aluminium alloy extrudates. To perform this task, an optimization problem is defined and solved using a standard non‐linear programming algorithm. Ingredients of this algorithm include (1) the process parameters to be optimized, (2) a cost function: the weighted average of the precipitate number density distribution, (3) constraint functions to limit the temperature gradient (and hence distortion and residual stress) and exit temperature, and (4) their sensitivities with respect to the process parameters. The cost and constraint functions are dependent on the temperature and precipitate size which are obtained by balancing energy to determine the temperature distribution and by using a reaction‐rate theory to determine the precipitate particle sizes and their distributions. Both the temperature and the precipitate models are solved via the discontinuous Galerkin finite element method. The energy balance incorporates non‐linear boundary conditions and material properties. The temperature field is then used in the reaction rate model which has as many as 105 degrees‐of‐freedom per finite element node. After computing the temperature and precipitate size distributions we must compute their sensitivities. This seemingly intractable computational task is resolved thanks to the discontinuous Galerkin finite element formulation and the direct differentiation sensitivity method. A three‐dimension example is provided to demonstrate the algorithm. Copyright © 2004 John Wiley & Sons, Ltd.
Analytical stiffness matrices with Green–Lagrange strain measure
Authors: Pedersen Pauli 
Published: December 2004

AbstractSeparating the dependence on material and stress/strain state from the dependence on initial geometry, we obtain analytical secant and tangent stiffness matrices. For the case of a linear displacement triangle with uniform thickness and uniform constitutive behaviour closed‐form results are listed, directly suited for coding in a finite element program.The nodal positions of an element and the displacement assumption give three basic matrices of order three. These matrices do not depend on material and stress/strain state, and thus are unchanged during the necessary iterations for obtaining a solution based on Green–Lagrange strain measure.The approach is especially useful in design optimization, because analytical sensitivity analysis then can be performed. The case of a three node triangular ring element for axisymmetric analysis involves small modifications and extension to four node tetrahedron elements should be straight forward. Copyright © 2004 John Wiley & Sons, Ltd.
DSC‐Ritz method for high‐mode frequency analysis of thick shallow shells
Authors: Lim C. W. , Li Z. R. , Wei G. W. 
Published: December 2004

AbstractThis paper addresses a challenging problem in computational mechanics—the analysis of thick shallow shells vibrating at high modes. Existing methods encounter significant difficulties for such a problem due to numerical instability. A new numerical approach, DSC‐Ritz method, is developed by taking the advantages of both the discrete singular convolution (DSC) wavelet kernels of the Dirichlet type and the Ritz method for the numerical solution of thick shells with all possible combinations of commonly occurred boundary conditions. As wavelets are localized in both frequency and co‐ordinate domains, they give rise to numerical schemes with optimal accurate, stability and flexibility. Numerical examples are considered for Mindlin plates and shells with various edge supports. Benchmark solutions are obtained and analyzed in detail. Experimental results validate the convergence, stability, accuracy and reliability of the proposed approach. In particular, with a reasonable number of grid points, the new DSC‐Ritz method is capable of producing highly accurate numerical results for high‐mode vibration frequencies, which are hitherto unavailable to engineers. Moreover, the capability of predicting high modes endows us the privilege to reveal a discrepancy between natural higher‐order vibration modes of a Mindlin plate and those calculated via an analytical relationship linking Kirchhoff and Mindlin plates. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of nano‐barium titanate on the mechanical, electrical and solubility performance of ferrite‐filled poly(ether ether ketone) composites
Authors: Dwivedi Mayank , Alam Sarfaraz , Verma G L 
Published: December 2004

AbstractFerrite and nano‐barium titanate reinforced poly(ether ether ketone) (PEEK) composites were made by compression moulding technology. The effects of reinforcement of the ferrite and nano‐barium titanate on the PEEK matrix were studied with the aim assessing its potential as a radar‐absorbing structural material (RASM). With an increase in the percentage filling of ferrite in the PEEK matrix, the specific gravity, hardness, tensile and flexural moduli, brittleness, dielectric constant, loss tangent and reflection losses were increased, while the tensile and flexural strengths, and elongation at break, were decreased. With increasing nano‐barium titanate reinforcement in the ferrite‐filled PEEK composites, the specific gravity, hardness, tensile and flexural strengths, tensile modulus and dielectric constant were comparatively increased, while the elongation at break, flexural modulus and loss tangent (marginally) were decreased. Reinforcement of the nano‐barium titanate caused a comparatively marginal reduction in the loss tangent, although no effect on reflection losses was observed. The solubility resistance of the ferrite‐filled PEEK composites was improved with reinforcement by the nano‐barium titanate. Copyright © 2004 Society of Chemical Industry
Characterization of strong polyelectrolyte hydrogels based on poly(vinyl alcohol)
Authors: Atta Ayman M , Arndt Karl‐Friedrich 
Published: December 2004

AbstractMaleic anhydride (MA) was grafted onto both partially and fully hydrolyzed poly(vinyl alcohol) (PVA) in the presence of an initiator. Strong polyelectrolyte polymers were prepared by sulfonation of PVA–MA grafts. The sulfonation was completed by reaction of hydroxyl groups of PVA–MA grafts with two different sulfonating reagents (chlorosulfonic acid and pyridine sulfonic acid). The sulfonation degree was evaluated by acid–base titration and 1H NMR analysis. The solution behaviour of the prepared grafts was evaluated from viscosity measurements. Four kinds of water‐insoluble PVA–MA and PVA–MA‐SO3H hydrogels were prepared by heat treatment, physical gelation and chemical crosslinking with different weight ratios of N,N‐methylene bisacrylamide (MBA) crosslinker. The swelling parameters were measured for all prepared gels in deionized water and aqueous solutions at different pH values from 2 to 12 having constant ionic strength (I = 0.1). All gels exhibit a different swelling behaviour upon environmental pH changes. Copyright © 2004 Society of Chemical Industry
An approach to one‐dimensional conductive polymer composites
Authors: Tai Xiangyang , Wu Guozhang , Tominaga Yoichi , Asai Shigeo , Sumita Masao 
Published: December 2004

AbstractA substantial approach to one‐dimensional (1D) electrically conductive composites was proposed which was based on the thermodynamic analysis of electric‐field‐induced particle alignment in a nonpolar thermoplastic polymer matrix. The process condition window was based on the real‐time exploration of dynamic percolation under different electric fields with carbon black (CB)‐filled polyethylene as a model. The CB content was the main factor of the process condition. Its upper limit was set as the critical percolation concentration at the thermodynamic equilibrium state without an electric field to eliminate the possibility of conductive network formation perpendicular to the electric‐field direction, whereas its lower limit the critical percolation concentration at the thermodynamic equilibrium state under a critical electric field (E*). A composite with CB content in this window, isothermally treated in an electric field not less than E*, showed conductivity in the electric‐field direction about 105 times larger than that in the perpendicular direction. A 1D cluster structure in the direction of the electric filed was confirmed with scanning electron microscopy morphology observations. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 184–189, 2005
Calculation of spin‐orbit coupling within the LFDFT: Applications to [NiX4]2− (XF−, Cl−, Br−, I−)
Authors: Atanasov Mihail , Rauzy Cédrick , Baettig Pio , Daul Claude 
Published: December 2004

AbstractSpin‐orbit coupling has been introduced into our newly developed ligand field density functional theory (LFDFT), using the zero‐order regular approximation as implemented into the Amsterdam density functional (ADF) code. Application of the formalism to a series of NiX (XF−, Cl−, Br−, I−) compounds shows the increasing importance of intra‐ligand spin‐orbit coupling across the F, Cl, Br, I series, to lead to sign reversal (in the case of Br− and I−) of the spin‐orbit splitting within the t2‐orbitals manifold of Ni2+. Symmetry lowering from Td to D2d, due to the Jahn–Teller coupling for the e4t configuration of NiX, is used to manifest further the effect of bonding changes on the sign and magnitude of the spin‐orbit constant. Ligand field and spin‐orbit coupling matrices are found to be correlated, with the higher erxtent of antibonding being accompanied by lower values of the spin‐orbit coupling constant. In cases of little or no symmetry, this leads to situations in which ligand field and spin‐orbit coupling cannot be neatly separated in the mathematical description. Using these results, the electronic energy levels of this series of compounds are predicted to be in good agreement with available spectral and magnetic data from literature. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005