bluuebunny/crossref_metadata_2025_split huggingface dataset:
Titanium Triamidotriamine Compounds: Syntheses, Structures and Redox Properties
Authors: Martins Ana M. , Ascenso José R. , de Azevedo Cristina G. , Dias Alberto R. , Duarte M. Teresa , Ferreira Humberto , Ferreira M. João , Henriques Rui T. , Lemos M. Amélia , Li Li , da Silva João F. 
Published: April 2005

AbstractThe preparation of 1,4,7‐{NH(2‐C6H4F)SiMe2}3‐1,4,7‐triazacyclononane (H3N3‐F[9]N3) and 1,4,8‐{N(H)PhSiMe2}3‐1,4,8‐triazacycloundecane (H3N3[11]N3), and their sodium derivatives Na3N3‐F[9]N3(THF)2 and Na3N3[11]N3(THF)2, is described. The reaction of [TiCl3(THF)3] with Na3N3‐F[9]‐N3(THF)2 and Na3N3[11]N3(THF)2 leads to [Ti{N3‐F[9]N3}] and [Ti{N3[11]N3}]. The titanium complexes react readily with I2 to give the TiIV derivatives [Ti{N3‐F[9]N3}]I and [Ti{N3[11]N3}]I. All titanium compounds display distorted trigonal prismatic geometries where the metal is coordinated to the six nitrogen donors. Fluxional processes that convert the conformations of the five‐ and six‐membered metallacycles and the Δ and Λ enantiomers of [Ti{N3[11]N3}]I have been identified in solution. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Highly Active Neutral Nickel(II) Complexes Bearing P,N‐Chelate Ligands: Synthesis, Characterization and Their Application to Addition Polymerization of Norbornene
Authors: Wang Hai‐Yu , Jin Guo‐Xin 
Published: April 2005

AbstractNeutral nickel(II) complexes [[R–NP]NiPh(PPh3)](1, R = H; 2, R = CH3) bearing P,N‐chelate ligands ([H–NP] = (2‐diphenylphosphanyl)benzenamine L1; [CH3–NP] = (2‐diphenylphosphanyl) N‐methylbenzenamine L2) have been synthesized and characterized. The molecular structure of complex 1 has been confirmed by single‐crystal X‐ray analyses. Afteractivation with methylaluminoxane (MAO), catalytic precursors 1 and 2 could polymerize norbornene to afford addition‐type polynorbornene (PNB) with very high activities (4.43 × 107 g‐PNB mol–1‐Ni h–1), high molecular weight Mw (3.07 × 106 g mol–1) and moderate molecular weight distribution Mw/Mn. Catalytic activities, polymer yield, Mw and Mw/Mn of PNB have been investigated under various reaction conditions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Acidities of Nitrous and Nitric Acids
Authors: Exner Otto , Böhm Stanislav 
Published: April 2005

AbstractThe energies of nitrous and nitric acid and their anions were calculated at the MP2(FC)/6‐311++G(2d,2p) level. Their acidity was related to the acidity of hydroxylamine derivatives using isodesmic reactions. This procedure reveals that the molecules of HNO2 and HNO3 are strongly stabilized (by 119 or 206 kJ·mol–1, respectively) but their anions are stabilized even more (by 282 or 428 kJ·mol–1). The acidity of these acids is thus caused by the low energy of their anions and not by the high energy of the acid molecules, similarly to the case of carboxylic acids. This stability may be partly due to resonance but the contribution of this effect can only be estimated. Correlation of the acidities of various acids with the inductive and polarization parameters led to the following estimate: in the case of nitrous acid 46 % of the acidity enhancement is due to resonance while in the case of nitric acid it is 25 %. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Catalytic Properties and the Role of Copper in Bovine and Lentil Seedling Copper/Quinone‐Containing Amine Oxidases: Controversial Opinions
Authors: Agostinelli Enzo , Belli Francesca , Dalla Vedova Laura , Longu Silvia , Mura Anna , Floris Giovanni 
Published: April 2005

AbstractIn this microreview, the differences in the catalytic cycle of two copper/quinone‐containing amine oxidases, one from lentil seedlings, representative of plant enzymes, and the other from bovine serum, typical of mammalian enzymes, are discussed. Although both enzymes are involved in the control of the levels of mono‐, di‐, and polyamines, and contain the same organic cofactor, the quinone of 2,4,5‐trihydroxyphenylalanine, known as TOPA or TPQ, lentil amine oxidase operates in a different way and with a much higher catalytic activity than the bovine serum enzyme. The role of copper in the two enzymes is also discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Analysis of lidar fields using local polynomial regression
Authors: Lindström Torgny , Holst Ulla , Weibring Petter 
Published: April 2005

AbstractLidar (light detection and ranging) is a laser based tool for remote measurement of several atmospheric species of importance. We consider the analysis of a field, consisting of several consecutive measurements, in which the concentrations are proportional to the derivatives in the directions of the light paths. Inference is based on local polynomial kernel regression, both for estimation of the derivatives of the mean‐function and for estimation of the variance‐function. Bivariate bandwidth matrices are selected using the empirical‐bias bandwidth selector (EBBS) adapted to allow for dependent data and to support selection of bivariate bandwidths. The estimation procedure is demonstrated on measurements of atomic mercury from the Solvay industries mercury cell chlor‐alkali plant in Rosignano Solvay, Italy. Copyright © 2005 John Wiley & Sons, Ltd.
Optimizing groundwater long‐term monitoring networks using Delaunay triangulation spatial analysis techniques
Authors: Ling Meng , Rifai Hanadi S. , Newell Charles J. 
Published: April 2005

AbstractGroundwater long‐term monitoring (LTM) is a costly activity required at most subsurface remediation sites. Many existing LTM networks need to be optimized to reflect changes in site conditions and to increase their effectiveness in defining the plume. A spatial analysis method using Delaunay triangulation techniques was developed to eliminate redundant monitoring points and to locate new wells where additional data are needed. This method uses Delaunay triangulation of the monitoring network for site discretization and assesses the concentration estimation error at each monitoring location to judge its relative contribution to the spatial plume characterization. Locations where the concentration estimation error is small are considered redundant and become candidates for elimination. New monitoring locations are identified where the projected concentration estimation errors are high. Tests comparing the Delaunay method to a fate and transport analytical model illustrated the attributes and effectiveness of the method. Application to a benzene plume site demonstrated that results from Delaunay triangulation agree well with geostatistical approaches. Although the method is relatively less accurate, and lacks the resolution obtained with the geostatistical approach, it is computationally efficient and simple to implement by non‐statisticians. Copyright © 2005 John Wiley & Sons, Ltd.
Shore platform morphology on a rapidly uplifting coast, Wellington, New Zealand
Authors: Kennedy D. M. , Beban J. G. 
Published: April 2005

AbstractThe coast of Wellington, New Zealand, is tectonically active and contains a series of uplifted and contemporary shore platforms that are developed in Triassic Greywacke. The platform profiles are rugged with relief of metre scale common. The surveyed platforms were formed at, and at two distinct levels 1–1·5 and 2–2·5 m above, mean sea level. They range in width up to 70 m and are highly fractured with fracture densities in excess of 20[sol ]m2 common. The rate of development of these platforms is rapid, with lateral erosion rates of up to 0·15 m[sol ]yr calculated, allowing platform development to occur over centennial scales. Even given this rapid development, continued instantaneous uplift of the coast has meant they are unable to reach an equilibrium state, whereby the effectiveness of wave processes in removing material is reduced by platform extension. The co‐seismic uplift means that the rear of the platforms is raised beyond the limits of marine process and has become an area of deposition. Although no direct process measurements were made the highly fractured nature of the bedrock appears to play a major role in platform evolution, with wave processes being easily able to pluck blocks as evidenced by fresh erosion scars and active gravel beaches at the rear of many platforms. This coast therefore represents an extremely dynamic youthful shore platform environment, where the processes of marine abrasion can be observed over historical timescales. Copyright © 2005 John Wiley & Sons, Ltd.
Finite‐difference 4th‐order compact scheme for the direct numerical simulation of instabilities of shear layers
Authors: Jiang Yan , Floryan J. M. 
Published: April 2005

AbstractAn algorithm based on the 4th‐order finite‐difference compact scheme is developed and applied in the direct numerical simulations of instabilities of channel flow. The algorithm is illustrated in the context of stream function formulation that leads to field equation involving 4th‐order spatial derivatives. The finite‐difference discretization in the wall‐normal direction uses five arbitrarily spaced points. The discretization coefficients are determined numerically, providing a large degree of flexibility for grid selection. The Fourier expansions are used in the streamwise direction. A hybrid Runge–Kutta/Crank–Nicholson low‐storage scheme is applied for the time discretization. Accuracy tests demonstrate that the algorithm does deliver the 4th‐order accuracy. The algorithm has been used to simulate the natural instability processes in channel flow as well as processes occurring when the flow is spatially modulated using wall transpiration. Extensions to three‐dimensional situations are suggested. Copyright © 2005 John Wiley & Sons, Ltd.
UV‐Curable Cycloaliphatic Epoxide Based on Modified Linseed Oil: Synthesis, Characterization and Kinetics
Authors: Zou Kunrong , Soucek Mark D. 
Published: April 2005

AbstractSummary: Linseed oil was derivitized with 1,3‐butadiene via a Diels‐Alder reaction. The cycloaddition adduct was then epoxidized using a hydrogen peroxide/quaternary ammonium tetrakis(diperoxotungsto) phosphate system. The cyclohexene derivitized linseed oil (CLO) and the epoxidized cyclohexene derivatized linseed oil (ECLO) were characterized by 1H NMR, 13C NMR, and FT‐IR. In addition, 2D NMR measurements (COSY) were performed on CLO and ECLO to identify the cyclohexyl structures. Molecular weight was determined by ESI‐MS and GPC. The ECLO was photo‐polymerized using UV‐light, and the kinetics of the photo‐curing reactions was evaluated by real‐time FT‐IR and photo‐DSC. All the characterizations supported the successful introduction of cyclohexyl structure to the backbone of linseed oil directly and indirectly. Real‐time FT‐IR and photo‐DSC indicated the slightly improved reactivity of ECLO.Ideal structure of cyclohexene linseed oil (CLO).imageIdeal structure of cyclohexene linseed oil (CLO).
Synthesis and Liquid Crystalline Properties of Poly(ethylene oxide) Brushes with Amphiphilic Side Groups
Authors: Kim Jong‐Uk , Lee Jong‐Chan 
Published: April 2005

AbstractSummary:Poly(ethylene oxide)s containing decylthiomethyl (DTP), decylsulfonylmethyl (DSP), methyl‐oligo(ethylene oxide) thiomethyl (MnOTP), methyl‐oligo(ethylene oxide) sulfonylmethyl (MnOSP), decyl‐oligo(ethylene oxide) thiomethyl (DnOTP), and decyl‐oligo(ethylene oxide) sulfonylmethyl (DnOSP) groups in the side‐chains, wheren(the number of ethylene oxide units) = 1, 2, 3, or 4 for DnOTP and DnOSP, andn = 2, 3, or 7 for MnOTP and MnOSP, were synthesized to study the effect of the structure of the side‐chains on the ordered phases of the polymers. All of the MnOSPs, as well as M2OTP and M3OTP, were found to be amorphous polymers. DTP, M7OTP, D1OTP, D2OTP, and D3OTP showed crystalline phases below their isotropic temperatures. DSP, D1OSP, D2OSP, D3OSP, D4OSP, and D4OTP were found to be liquid crystalline. Therefore, the phase separation facilitated by the introduction of the sulfone group and/or by the addition of the longer ethylene oxide units between the ethylene oxide backbones and the hydrophobic decyl tails was found to be a key factor in the formation of the liquid crystalline phases. These ordered phases were characterized using differential scanning calorimetry, polarized optical microscopy, and X‐ray diffraction.Schematic illustration of the structures of poly(ethylene oxide) brushes showing liquid crystalline phases.imageSchematic illustration of the structures of poly(ethylene oxide) brushes showing liquid crystalline phases.
Confocal Raman Spectroscopy – Applications on Wood, Pulp, and Cellulose Fibres
Authors: Röder Thomas , Sixta Herbert 
Published: April 2005

AbstractThe manifold possibilities using dispersive Raman spectroscopy along the production chain from wood to cellulose fibre are presented here: The distribution of the lignin, cellulose, and added resins in the wood cell; additives inside regenerated cellulose fibres; their accessibility and reactivity. On‐line measurements during the phase transition of magnesium sulphite ‐hexahydrate into ‐trihydrate are performed in a stirring vessel.
Characterization of Water‐Soluble Cellulose Derivatives in Terms of the Molar Mass and Particle Size as well as Their Distribution
Authors: Kulicke W.‐M. , Clasen Christian , Lohman Claudia 
Published: April 2005

AbstractThe property profile of cellulose derivatives dissolved in aqueous solvents is not only dependent on the chemical composition (average‐, molar‐ or regiospecific degree of substitution, as well as the substitution along the chain), solvent, temperature and concentration but also on the molar mass and the particle size. All this information can be obtained from the Mark‐Houwink‐Sakurada‐relationship ([;gh]‐M‐) or the RG‐M‐relationship, if these are at hand. These relationships are suitable for a specific degree of substitution. The RG‐M‐relationship has only been determined and published for a few water‐soluble cellulose derivatives.The prerequisite is the availability of a homologous series of samples with the same chemical composition. In this paper it is shown that only the ultrasonic degradation is able to create such a series.Due to the ability of coupled methods of analysis to acquiring absolute data, molar mass and particle size distributions have been compiled in recent years. Using such methods it was possible to determine molar mass and particle size distributions of several aqueous cellulose derivative solutions by combining a fractionation unit (size exclusion chromatography (SEC) or flow field‐flow fractionation (FFFF)) with multi angle laser light scattering (MALLS) for the detection of Mw and RG and concentration detection (DRI). Results for nonionic cellulose ethers, mixed cellulose ethers, ionic carboxymethyl cellulose, sulfoethyl cellulose, hydrophobically modified hydroxyethyl cellulose were obtained and are partially discussed with focus on the recovery of cellulose derivates after fractionation and the impact on the distribution functions.
Studies on the Thermostability of Modified Lyocell Dopes
Authors: Wendler Frank , Meister Frank , Heinze Thomas 
Published: April 2005

AbstractModification of Lyocell dopes with special additives enables the creation of new innovative materials. Additives with functional groups and active surfaces may initiate complex chemical reactions in cellulose/N‐methylmorpholine‐N‐oxide monohydrate (NMMO) solutions. The effect of carboxylic groups on the thermostability was investigated by incorporating of sugar acids, acidic ion exchange resins (IER) and superabsorbing polymers (SAP) into the solutions. Whereas the sugar acids show strict correlations between the carboxyl group content in solution and onset temperature, viscosity reduction, coloration and by‐product formation, the additives show an induction time, which finally leads to accelerated degradation reactions. The cellulose/NMMO solutions were additionally characterized by means of UV/VIS spectroscopy.
Microscopic Visualization of Nanostructures of Cellulose Derivatives
Authors: Liebert Tim , Hornig Stephanie , Hesse Stephanie , Heinze Thomas 
Published: April 2005

AbstractMicroscopy has proved to be a valuable tool for the investigation of supermolecular structures of cellulose derivatives. Thus, with AFM it was possible to show that statistically functionalized derivatives (degree of substitution below 3) form specific aggregates called fringed micelles. In contrast, derivatives with a non‐statistic distribution exhibit a more network‐like structure as known for galactomannans consisting of block‐like structures. If samples are prepared by deposition of dilute solutions of polyelectrolytes on mica and drying at elevated temperature, the formation of nanorings is observed. In addition, AFM and REM were applied to investigate the morphology of membranes prepared of cellulose esters with unsaturated substituents. It was shown that cross‐linking of the polymer chains in the membranes does not lead to a change in the nanostructure of the surface, i.g., the surface roughness and the pore sizes were not modified.
Dynamic 13C NMR studies of ligand exchange in linear (d10) silver(I) and gold(I) and square‐planar (d8) rhodium(I) homoleptic metal carbonyl cations in superacidic media
Authors: Ahsen B. von , Bach C. , Balzer G. , Bley B. , Bodenbinder M. , Hägele G. , Willner H. , Aubke F. 
Published: April 2005

AbstractThe dynamic CO exchange of the monovalent metal carbonyl cations [Ag(13CO)]+, [Au(13CO)2]+–Au(13CO) SO3F and [Rh(12CO)4−x(13CO)x]+ (x⩽1) in superacidic solutions was studied by variable‐temperature 13C NMR methods. The exchange rates are strongly dependent on the acidity of the solvent, the concentration of metal carbonyl cations and temperature. Whereas a suitable exchange rate of the Ag(I) system is only accessible in magic acid (HSO3F–SbF5), the more stable Au(I) and Rh(I) systems were studied in the less acidic fluorosulfuric acid. Selected solutions of Ag(I), Rh(I) and Au(I) yielded activation barriers ΔG* of 42.7, 43.5, and 56.2 kJ mol−1 respectively. Copyright © 2005 John Wiley & Sons, Ltd.
Solid‐state NMR study of Schiff base derivatives of 2‐hydroxynaphthaldehyde. Deuterium isotope effects on 15N chemical shifts in the solid state
Authors: Rozwadowski Z. , Schilf W. , Kamieński B. 
Published: April 2005

AbstractSchiff base derivatives of 2‐hydroxynaphthylaldehyde were studied by means of 13C and 15N cross‐polarization magic angle spinning NMR spectroscopy and deuterium isotope effects on 15N chemical shifts, ΔN(D), in the solid state. ΔN(D) in the solid state provided evidenced for the presence of a dynamic proton transfer equilibrium in the solid state at the room temperature. Copyright © 2005 John Wiley & Sons, Ltd.
On parallel machine replacement problems with general replacement cost functions and stochastic deterioration
Authors: Childress Suzanne , Durango‐Cohen Pablo 
Published: April 2005

AbstractThe parallel machine replacement problem consists of finding a minimum cost replacement policy for a finite population of economically interdependent machines. In this paper, we formulate a stochastic version of the problem and analyze the structure of optimal policies under general classes of replacement cost functions. We prove that for problems with arbitrary cost functions, there can be optimal policies where a machine is replaced only if all machines in worse states are replaced (Worse Cluster Replacement Rule). We then show that, for problems with replacement cost functions exhibiting nonincreasing marginal costs, there are optimal policies such that, in any stage, machines in the same state are either all kept or all replaced (No‐Splitting Rule). We also present an example that shows that economies of scale in replacement costs do not guarantee optimal policies that satisfy the No‐Splitting Rule. These results lead to the fundamental insight that replacement decisions are driven by marginal costs, and not by economies of scale as suggested in the literature. Finally, we describe how the optimal policy structure, i.e., the No‐Splitting and Worse Cluster Replacement Rules, can be used to reduce the computational effort required to obtain optimal replacement policies. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005
Poly(styrene–b–ethylene/butylene–b–styrene)/cobalt ferrite magnetic nanocomposites
Authors: Rajan Guru S. , Mauritz Kenneth A. , Stromeyer Stacy L. , Kwee Tety , Mani Prakash , Weston James L. , Nikles David E. , Shamsuzzoha Mohammad 
Published: April 2005

AbstractMagnetic nanoparticles were created in or around the sulfonated (s) polystyrene domains in a poly[styrene–b–(ethylene–co–butylene)–b–styrene)] block copolymer (BCP) using an in situ inorganic precipitation procedure. The sBCP was neutralized with a mixed iron/cobalt chloride electrolyte, and the doped samples were converted to their oxides by reaction with sodium hydroxide. Transmission electron microscopy indicated the presence of nanoparticles having diameters of 20–50 nm. Metal oxide particle structures were studied using wide angle X–ray diffraction, which revealed that they were inverse spinel cobalt iron oxide crystals. Thermogravimetric analysis provided the weight percent of the inorganic component and nanocomposite thermal decomposition profile. Modulated differential scanning calorimetry studies suggested that the inorganic inclusions were selectively grown in the polystyrene hard block phase. These nanocomposites were shown, using alternating gradient magnetometry, to be ferrimagnetic at room temperature. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1475–1485, 2005
Correlated one‐electron wave functions
Authors: Weiner B. , Ortiz J. V. 
Published: April 2005

AbstractA one‐electron theory of many‐electron systems that explicitly describes electron–electron correlation may be based on the observation that antisymmetrized geminal power (AGP) states are completely characterized by the occupation numbers of their first‐order reduced density operators (FORDO) and a set of canonical general spin–orbitals (CGSOs), which are in general distinct from the natural general spin–orbitals. Because the FORDO alone does not determine an AGP state, a density matrix functional may be defined. A generalization of the independent‐particle Fock operator serves to express the total state energy in terms of ionization energies, kinetic energies, and potential energies of the CGSOs. A one‐electron picture of chemical bonding emerges from this theory. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
US28 actions in HCMV infection: lessons from a versatile hijacker
Authors: Boomker J. M. , van Luyn M. J. A. , The T. H. , de Leij L. F. M. H. , Harmsen M. C. 
Published: April 2005

AbstractMimicking host proteins is a strategy adopted by several herpesviruses to exploit the host cell for their own benefit. In this respect the human cytomegalovirus (HCMV) chemokine receptor homologue US28, has been extensively studied. Molecular pirates such as US28 can teach us about crucial events in HCMV infection and may either offer a potential target for antiviral therapy or provide an alternative strategy to immune suppression. Despite elaborate research into the chemokine binding affinity, signalling properties, intracellular trafficking and expression kinetics of US28, a solid hypothesis about the role of US28 in HCMV infection has not yet been proposed. It appears that US28 may behave as a molecular pirate that employs smart strategies for cell entry, host gene regulation and immune evasion. This review will elaborate on these aspects of US28 biology and discuss possible implications for HCMV infection. Copyright © 2005 John Wiley & Sons, Ltd.