bluuebunny/crossref_metadata_2025_split huggingface dataset:
A critical comparison of MINDO/3, MNDO, AM1, and PM3 for a model problem: Carbon clusters C2‐C10. An ad hoc reparametrization of MNDO well suited for the accurate prediction of their spectroscopic constants
Authors: Martin J. M. L. , François J. P. , Gijbels R. 
Published: January 2005

AbstractDissociation energies and potential energy surface features for the carbon clusters C2 to C10 are compared with ab initio or experimental results for the semiempirical methods MINDO/3, MNDO, AM1, and PM3. Quite surprisingly, MINDO/3 gives a rather good account of the various structures and electronic states, unlike the other three methods. MINDO/3 tends towards systematic overestimates of binding energies, the other methods to systematic gross underestimates. Reparametrization of the diatomic parameters α, βs, and βp for exact reproduction of the experimental data for C3 results in much improved values for binding energies, but fails to correct the state splittings. Also reparametrizing Uss, Upp, ζs, and ζp to reproduce the ab initio linear‐rhombic energy difference in C4 results in a much improved description of the other states. For the linear structures, computed harmonic frequencies with the latter parameters are in surprisingly good agreement with experimental or correlated ab initio data, where available; experimental values are consistently overestimated by about 40 cm−1. Other results are comparable in quality to good ab initio treatments. The experimental IR bands at 2128 and 1892 cm−1, formerly assigned to C9, should be reassigned to linear C7. The intense 1997 cm−1 feature almost certainly belongs to C9; bands at 1952 and 1197 cm−1 both belong to linear C6. Tentative assignments of bands in the 1600–1850 cm−1 region to various cyclic structures of C6, C8, and C10 have been made. As such, this suggests a new and promising procedure for the theoretical study of large molecules in general, and of large clusters in particular.
Evaluation of PM3, AM1, and MNDO for calculation of higher energy ionization potentials
Authors: Gano James E. , Jacob E. Jean , Roesner Rebecca 
Published: January 2005

AbstractHigher ionization energies were calculated with PM3, AM1, and MNDO for three series of molecules, representative small molecules, molecules containing heteroatoms, and sterically congested alkenes. Values from PM3, AM1, and MNDO were compared to experimental values. In most instances, the semiempirical calculations correctly predict the ordering of higher ionization energies. In the absence of steric hindrance, MNDO is the method of choice. Within groups of molecules, AM1 performs better on hydrocarbons, especially twisted hydrocarbons, than PM3. PM3 commonly gives sigma orbitals which are too high in energy compared to related pi orbitals. PM3 performed better than AM1 with molecules containing oxygen, but failed to give the correct geometry for hydrogen peroxide.
Where is the blood–brain barrier … really?
Authors: Ge Shujun , Song Li , Pachter Joel S. 
Published: January 2005

AbstractFew terms in the biomedical lexicon are as widely recognized as the phrase blood–brain barrier (BBB). Indeed, it immediately conjures up a “barricade” between the blood and the brain, a feature often considered more obstacle than safeguard. In truth, the BBB performs in both capacities, and it is precisely this duality that imparts such a vital role to the BBB in influencing physiological and pathophysiological processes in the CNS. Although the concept is more than a century old, the BBB continues to remain enigmatic in both substance and idea, with seemingly resolved issues once again beckoning for clarification. In this regard, recent technological advancements, such as sequencing of the human genome and development of microarray analysis, have illuminated novel aspects of vascular gene expression and provoked reconsideration of the cellular and biochemical makeup of the BBB. In light of the critical impact of the BBB in the realms of science and medicine, this Mini‐Review will revisit the topic of the composition of the BBB, specifically highlighting how recent developments in endothelial biology have prompted a reevaluation of its precise vascular location. We have intentionally avoided discussing generalized features of the BBB, as these have been skillfully described elsewhere as noted. © 2005 Wiley‐Liss, Inc.
Transport of neurofilaments in growing axons requires microtubules but not actin filaments
Authors: Francis Franto , Roy Subhojit , Brady Scott T. , Black Mark M. 
Published: January 2005

AbstractNeurofilament (NF) polymers are conveyed from cell body to axon tip by slow axonal transport, and disruption of this process is implicated in several neuronal pathologies. This movement occurs in both anterograde and retrograde directions and is characterized by relatively rapid but brief movements of neurofilaments, interrupted by prolonged pauses. The present studies combine pharmacologic treatments that target actin filaments or microtubules with imaging of NF polymer transport in living axons to examine the dependence of neurofilament transport on these cytoskeletal systems. The heavy NF subunit tagged with green fluorescent protein was expressed in cultured sympathetic neurons to visualize NF transport. Depletion of axonal actin filaments by treatment with 5 μM latrunculin for 6 hr had no detectable effect on directionality or transport rate of NFs, but frequency of movement events was reduced from 1/3.1 min of imaging time to 1/4.9 min. Depolymerization of axonal microtubules using either 5 μM vinblastine for 3 hr or 5 μg/ml nocodazole for 4–6 hr profoundly suppressed neurofilament transport. In 92% of treated neurons, NF transport was undetected. These observations indicate that actin filaments are not required for neurofilament transport, although they may have subtle effects on neurofilament movements. In contrast, axonal transport of NFs requires microtubules, suggesting that anterograde and retrograde NF transport is powered by microtubule‐based motors. © 2005 Wiley‐Liss, Inc.
An evaluation of conventional wisdom of the factors underlying the digital divide: a case study of the Isle of Man
Authors: Skok Walter , Ryder George 
Published: January 2005

Abstract

The digital divide is defined as the gap that exists between those with and those without access to the Internet. Conventional wisdom is represented by the technology optimists' view that the divide is caused by societal barriers to Internet connectivity such as low levels of education, income and proliferation of technology. The technology pessimists disagree that these barriers cause the divide or that they are important enough to justify significant expenditure by government. This paper reports on a study to evaluate the validity of the optimistic position.
The Isle of Man (IOM) was selected for this evaluation because of its size, social stability, high levels of education and income and established e‐government programme. The premise of the research was that if the optimistic view is correct, lower or similar barriers to those found in the UK should result in higher or similar levels of Internet access in the IOM.
Prime causal factors of the digital divide, as purported by the optimists, were found to marginally favour the IOM. However, the test of Internet access revealed that the IOM trailed the UK connectivity level by some 12% to 14%, which is not as expected from the optimistic viewpoint. This unexpected outcome could constitute a dilemma for the IOM government in adopting an appropriate strategy to e‐government implementation and narrowing the digital divide.

Copyright © 2004 John Wiley & Sons, Ltd.
Strategy and financial management in the football industry
Authors: Grundy Tony 
Published: January 2005

Abstract

The literatures on strategy and finance have developed very separately, notwithstanding the fact that they have a common economic underpinning. Whilst a number of strategic theorists have looked at how strategic management facilitates the most effective leverage of economic resource, studies of the linkages between strategy and finance literatures are relatively few.
This appears odd because finance is pivotal in making the resource allocation decision in management, especially in major business investment and divestment decisions and in the financing strategies needed to accomplish this. Both financial management as a discipline and financing strategies also play a role in influencing stakeholder behaviour, which is critical in strategy.
Rarer still are studies of how strategy, financial management, financial strategies and stakeholders interact. With continuing examples of devastating corporates such as Enron and more recently Parmalat, it would seem surprising that theorists have been relatively disinterested in this important border between these disciplines.
This paper seeks to make a contribution to our understanding of the topic by focusing on the interesting case of the football industry. Whilst an earlier paper in this journal (Grundy, 2004) dealt with techniques for appraising strategic options to exploit product/market opportunities, financing strategy options warrant separate exploration.

Copyright © 2004 John Wiley & Sons, Ltd.
Working together: innovation and export links within highly developed and embryonic wine clusters
Authors: Aylward David 
Published: January 2005

Abstract

This paper examines innovation and export linkages within two distinct levels of wine cluster development. The aim of the paper, using empirical data from the Australian wine industry, is to demonstrate that the association between innovation and export activity intensifies as the cluster develops.

Copyright © 2004 John Wiley & Sons, Ltd.
Immunoadsorption of Cholesterol on Protein A Oriented Beads
Authors: Yavuz Handan , Denizli Adil 
Published: January 2005

AbstractSummary: Anti‐low density lipoprotein antibody (anti‐LDL) molecules were attached covalently and oriented through Protein A onto poly(2‐hydroxyethyl methacrylate‐ethylene glycol dimethacrylate) [poly(HEMA‐EGDMA)] beads in order to remove cholesterol specifically from hypercholesterolemic human plasma. Poly(HEMA‐EGDMA) beads were produced by suspension polymerization. Blood compatibility tests were performed. All the clotting times were increased when compared with control plasma. Loss of platelets and leukocytes was very low. The maximum anti‐LDL attachment was 11.6 mg · g−1 in the case of random immobilization and 28.3 mg · g−1 in the case of oriented immobilization. In the latter case, Protein A loading was 8.3 mg · g−1 at pH 7.5 (borate buffer, 0.15 M NaCl). There was low non‐specific cholesterol adsorption onto the poly(HEMA‐EGDMA) beads, about 0.83 mg · g−1. Random and oriented anti‐LDL attached beads adsorbed 8.2 mg and 11.7 mg cholesterol per g of bead from hypercholesterolemic human plasma, respectively. Up to 96% of the adsorbed cholesterol was desorbed. The binding‐elution cycle was repeated 6 times using the same beads. There was no significant loss of binding capacity.image
Principle of a New Immunoassay Based on Electrophoretic Mobility of Poly(styrene/α‐tert‐butoxy‐ω‐vinylbenzyl‐polyglycidol) Microspheres: Application for the Determination of Helicobacter pylori IgG in Blood Serum
Authors: Basinska Teresa , Wisniewska Monika , Chmiela Magdalena 
Published: January 2005

AbstractSummary: The principle of a novel latex diagnostic test for the determination of antibodies against Helicobacter pylori in blood sera is described. The test is based on the measurement of the electrophoretic mobility of the microspheres with immobilized H. pylori antigens. The electrophoretic mobility of these microspheres depends on the concentration of the antibodies against H. pylori in suspending medium. Particles with hydrophilic polyglycidol in the surface layer were used for the test. The microspheres were obtained by an emulsifier‐free emulsion copolymerization of styrene and α‐tert‐butoxy‐ω‐vinylbenzyl‐polyglycidol macromonomer ($\overline D _{\rm n}$ = 220 nm, diameter polydispersity factor $\overline D _{\rm w} /\overline D _{\rm n}$ = 1.02). Activation of polyglycidol hydroxyl groups with cyanuric chloride allowed for covalent immobilization of H. pylori antigens. The fraction of H. pylori not specifically adsorbed onto the microspheres was negligible. Changes of the electrophoretic mobility of the microspheres with the surface concentration of the covalently immobilized H. pylori antigens Γ = (1.6 ± 0.3) · 10−3 g m−2 were suitable for the detection of the antibodies in the sera of patients with titer in the range (determined by the indirect ELISA test) from 1:500 to 1:32 000.image
Evaluation of Oligo(ethylene glycol) Dimethacrylates Effects on the Properties of New Biodegradable Bone Cement Compositions
Authors: Łukaszczyk Jan , Śmiga Monika , Jaszcz Katarzyna , Adler Hans‐Jürgen P. , Jähne Evelyn , Kaczmarek Marcin 
Published: January 2005

AbstractSummary: New injectable, in situ curable liquid formulations consisting of biodegradable aliphatic polyester, i.e., poly(3‐allyloxy‐1,2‐propylene)succinate (PSAGE), methyl methacrylate (MMA), and hydrophilic oligo(ethylene glycol) dimethacrylates (OEGDMA) were investigated. The effect of MMA/OEGDMA ratio, OEGDMA molecular weight, i.e., the length of oligooxyethylene fragments, on the maximum curing temperature, setting time, compressive strength and modulus of the cured materials as well as their hydrophilicity were examined. The latter was characterized by determination of equilibrium water content and static water contact angle. The maximum temperature during crosslinking was found to decrease with increasing OEGDMA molecular weight and decreasing MMA/OEGDMA ratio. The setting time was affected strongly by the concentration of double bonds and was rapidly shortened with its increase. The compressive strength and compressive modulus values decreased with increasing OEGDMA molecular weight and decreasing MMA/OEGDMA ratio.Poly(3‐allyloxy‐1,2‐propylene succinate).imagePoly(3‐allyloxy‐1,2‐propylene succinate).
Kinetic Analysis and Optimization for the Catalytic Esterification Step of PPT Polymerization
Authors: Majumdar Saptarshi , Mitra Kishalay , Sardar Gautam 
Published: January 2005

AbstractSummary: A well‐validated kinetic scheme has been studied for PPT, poly(propylene terephthalate) polymerization process in batch and semi‐batch mode with tetrabutoxytitanium (TBOT), a proven catalyst. Optimization study and analysis for PPT are rare, as the industrial relevance of PPT just became vibrant due to the commercial availability of one of its monomers in industrial scale in the recent past. Correctness of the analysis is checked by a new approach and parameters for the model are estimated from available experimental data. Solubility of terephthalic acid (TPA) is less in reaction medium and this effect is also considered along with the reaction scheme. Several simulations have been performed to see various process dynamics and this ultimately helps in formulating optimization problems. Using recently developed and well tested real‐coded non‐dominated sorting genetic algorithm‐II, a state‐of‐the art evolutionary optimization algorithm, a couple of three objective optimization problems have been solved and corresponding Pareto sets are presented. Results show remarkably promising aspects of productivity enhancement with an improvement in product quality. Sensitivity analysis for relatively uncertain solubility parameter is also performed to estimate its effect over the proposed optimal solutions.Multiobjective Pareto front for 3 objectives: degree of polymerization, time and (bTPA + bPG).imageMultiobjective Pareto front for 3 objectives: degree of polymerization, time and (bTPA + bPG).
Molecular Dynamics Simulations of the Orientation and Reorientational Dynamics of Water and Polypyrrole Rings as a Function of the Oxidation State of the Polymer
Authors: López Cascales Jose J. , Otero Toribio F. 
Published: January 2005

AbstractSummary: Polypyrrole is one of the most widely‐studied conducting polymers due to its steady electrochemical response and good chemical stability in different solvents, including organic and inorganic ones. In this work, we provide for the first time valuable information in atomic detail concerning the steady and dynamic properties of pyrrole rings as a function of the oxidation state of the polymer. The study was carried out by Classical molecular dynamics simulation, where the system was modelled by 256 polypyrrole chains of 10 pyrrole rings each. Water was explicitly introduced in our simulations. Besides the uncharged or reduced state, two steady oxidation states of the polymer have been simulated by introducing a net charge (+1) on 85 and 256 of the polypyrrole chains. To balance the charges emerging in these oxidised states, 85 and 256 chloride ions (Cl−1) respectively, were introduced into the system. From an analysis of the simulated trajectories, the orientation and relaxation times of water and pyrrole rings were evaluated for the different oxidation states of the polymer across the polypyrrole/water interface. The calculated densities for different oxidation states describe the swelling or shrinking process during electrochemical oxidation or reduction respectively. The rotational relaxation times calculated for the polypyrrole rings decrease with increasing oxidation of the polymer, which is in a good agreement with experimental electrochemical data. Almost no variation in pyrrole ring orientation was measured for the different oxidation states of the polymer, even compared with polypyrrole bulk. As regards the water structure in the vicinity of the polypyrrole/water interface, both the orientation and orientation relaxation time were strongly affected by the presence of charges in the polymer. Thus, the water dipole was strongly orientated in the vicinity of the water/polypyrrole interface and its orientational relaxation time increased by one order of magnitude compared with bulk water, even when only one‐third of the total polymer chains were oxidised. The results attained in this work were validated with experimental results, when they were available.Polypyrrole ring orientation and water orientation at the polypyrrole/water interface. (a) 256 rPPy and (b)171 rPPy + 85 oPPy.imagePolypyrrole ring orientation and water orientation at the polypyrrole/water interface. (a) 256 rPPy and (b)171 rPPy + 85 oPPy.
Solvatochromic probes in supercritical fluids
Authors: Marcus Yizhak 
Published: January 2005

AbstractSupercritical fluids (SCFs) have in recent years become favored solvents for chemical reactions and separations. In order to be used as solvents, their solvation properties should be known, and solvatochromic probes are effectively used for this purpose. They have been applied foremost for supercritical carbon dioxide (SCCD), which is by far the most widely employed SCFs, but also for supercritical water, fluorocarbons and other substances. The probes have also found use in mixtures involving SCF and a more polar additive that have better solvation properties for polar solutes and in solvents expanded by dissolving in them SCCD. Clustering of the molecules of the SCF around the probe molecule is a common feature of the systems studied and this may reflect on the employment of the probes as stand‐ins for other solutes. Copyright © 2004 John Wiley & Sons, Ltd.
Preparation of ultrahigh‐molecular‐weight syndiotactic poly(vinyl pivalate) monodisperse microspheres by low‐temperature suspension polymerization of vinyl pivalate
Authors: Lyoo Won Seok , Kwak Jin Woo , Yeum Jeong Hyun , Ji Byung Chul , Lee Chul Joo , Noh Seok Kyun 
Published: January 2005

AbstractThe particle size distributions of poly(vinyl pivalate) (PVPi) produced from low‐temperature suspension polymerization of vinyl pivalate (VPi) with 2,2′‐azobis(4‐methoxy‐2,4‐dimethylvaleronitrile) (AMDMVN) as an initiator have been studied. By controlling various synthesis parameters, near‐monodisperse PVPi microspheres from 100 to 400 μm were obtained that are expected to be precursors of near‐monodisperse syndiotactic poly(vinyl alcohol) (PVA) microspheres for biomedical embolic applications. The mean particle diameter follows the relationship: the volume average diameter, Dvad ∝ Y0.26[VPi]0.52[AMDMVN]−0.25[PVA]0.40T−8.35Rpm−0.67, where Y, [VPi], [AMDMVN], [PVA], T, and Rpm are the fractional conversion, concentrations of VPi, AMDMVN, and suspending agent, polymerization temperature, and agitation speed during the polymerization of VPi, respectively. The polydispersity of the particle size distribution of PVPi decreased with decreasing conversion, [AMDMVN], T, and Rpm and with increasing [VPi]. In the case of [PVA], optimization of the suspension stability led to a narrow particle size distribution. Ultrahigh‐molecular‐weights PVPi and PVA (number‐average degrees of polymerization of PVPi (25,000–32,000) and PVA (14,000–17,500), of high syndiotactic diad content (63%), and of high ultimate conversion of VPi into PVPi (85–95%) were obtained by suspension polymerization at 10 °C, followed by saponification. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 789–800, 2005
Molar mass distributions and viscosity behavior of perfluorinated sulfonic acid polyelectrolyte aqueous dispersions
Authors: Lousenberg R. Daniel 
Published: January 2005

AbstractPerfluorinated sulfonic acid polyelectrolyte aqueous dispersions originating from similar polymer feed stocks and having similar compositions can have order‐of‐magnitude viscosity differences that are dependent on the manufacturing process. To better understand this phenomenon at the molecular level, a size exclusion chromatography method incorporating static light scattering detection was developed. The initial apparent mass distributions were broad and bimodal for all dispersions. A high‐molar‐mass shoulder was consistent with a previously postulated aggregate structure, and the evidence suggested that molecular aggregation accounted for viscosity variability. The apparent weight‐average molar masses ranged from 1.3 × 106 to 3.9 × 106 g mol−1. Upon the heating of the dispersions at or above 230 °C, the aggregate structure was broken down, and this resulted in similar low‐viscosity dispersions that had monomodal mass distributions. The weight‐average molar masses were reduced to approximately 2.5 × 105 g mol−1, and the polydispersities were approximately 1.7–1.8. Shear thinning with higher viscosities and apparent molar masses was rationalized with intrinsic viscosity and other measurements, which supported an anisotropic aggregate structure, with particles that could be significantly overlapped at nominal 11% concentrations. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 421–428, 2005
Cover Picture: Plasma Process. Polym. 1/2005
Authors: Barni Ruggero , Riccardi Claudia , Selli Elena , Massafra Maria Rosaria , Marcandalli Bruno , Orsini Francesco , Poletti Giulio , Meda Laura 
Published: January 2005

Cover: The effect of pressure in the surface modification of poly(ethylene terephthalate) fibers induced by SF6 plasma treatment is shown by atomic force microscopy images of (a) the untreated surface and of the fiber surface after 60 s long SF6 plasma treatment at (b) 0.05 mbar, (b) 0.20 mbar and (c) 0.40 mbar. The RF power was 105W; PET fabrics were plasma‐treated at 7.5 cm from the RF antenna.Further details can be found in the Full Paper by R. Barni, C. Riccardi, E. Selli,* M. R. Massafra, B. Marcandalli, F. Orsini, G. Poletti, and L. Meda on page 64.
Membrankonstruktionen – Form und Detail
Authors: Göppert Knut 
Published: January 2005

AbstractZum Gelingen einer Membrankonstruktion tragen die gewählte Form sowie die erarbeiteten Details in höchstem Maße bei. Wie im Schalenbau unterliegen die möglichen Formen strengen mechanischen Gesetzmäßigkeiten, die doppeltgekrümmte Formen und vorgespannte Tragsysteme erfordern. Die Verformungen der entmaterialisierten, weil ausschließlich auf Zug beanspruchten Konstruktionen und die genaue Verfolgung des Kraftflusses erfordern überdurchschnittliche Sorgfalt bei der Festlegung der Details.