bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fullerenes as sorbent materials for benzene, toluene, ethylbenzene, and xylene isomers preconcentration
Authors: Serrano Antonio , Gallego Mercedes 
Published: December 2005

AbstractA simple and novel SPE system for benzene, toluene, ethylbenzene, and xylene isomers (BTEX) compounds in water is proposed in which samples are directly propelled from a 15 mL glass vial through a sorbent column by means of a needle, thereby avoiding evaporative losses and the sorption of BTEX on the manifold materials. Following elution with 150 μL of ethyl acetate, 1 μL of extract is injected into a gas chromatograph–mass spectrometer system. A comparative study of various sorbent materials (C60 fullerene, Tenax TA, and RP‐C18) revealed C60 fullerene to be the best choice in terms of sensitivity (a likely result of its increased sample breakthrough volume), precision (the surfactant medium used to prepare samples minimizes evaporative losses), selectivity (C60 fullerene only interacts with nonpolar aromatic compounds), and reusability (columns containing 60 mg of C60 fullerene remain serviceable for at least 6 months). This C60 fullerene‐based method exhibits a linear range of 0.1–100 μg/L, a detection limit of 0.04 μg/L, and an RSD of ca. 3%. It was applied to the determination of BTEX in various types of water including sea and waste water with good precision.
Structural Information on the Transition Moments in Poly(ethylene‐2,6‐naphthalene) by Polarization FT‐IR Spectroscopy
Authors: Scott Alex , Hakme Chady , Stevenson Isabelle , Voice Alison 
Published: December 2005

AbstractOriented poly(ethylene‐2,6‐naphthalate) (PEN) has been characterised by polarised FT‐IR spectroscopy to determine the structural angles of the transition moments to the molecular chain axis. The bands at 1130 cm−1, 1142 cm−1 and 1602 cm−1, which have been previously assigned as having their transition dipole moments parallel to the chain axis, are confirmed as parallel bands. Bands at 767 cm−1 and 831 cm−1 are confirmed as perpendicular bands. However the band at 1708 cm−1 which has previously been assigned as a perpendicular band, is shown here to have its transition moment at 72° to the molecular axis.
Spectroscopic Investigations of Polymer Nanocomposites
Authors: Bokobza Liliane , Diop Amadou Lamine , Fournier Vincent , Minne Jean‐Baptiste , Bruneel Jean‐Luc 
Published: December 2005

AbstractThe addition of an inorganic component to polymers leads to improvements in various physical and mechanical properties. Various examples on filled elastomeric networks will show that a mechanical characterization can be nicely combined with a spectroscopic investigation for a better understanding of the properties of the composite materials.
Solid‐State NMR Characterization of Biodegradable Shape‐Memory Polymer Networks
Authors: Bertmer Marko , Buda Alina , Blomenkamp‐Höfges Iris , Kelch Steffen , Lendlein Andreas 
Published: December 2005

AbstractCopolymer networks synthesized from dilactide and diglycolide were characterized by solid‐state 13C CPMAS NMR in terms of composition, cross‐link density, and rate of cross‐linking by UV irradiation. The latter is directly evident by a signal at 44 ppm in the 13C NMR spectrum. Comparison of solid‐state NMR data with the determination of the gel content revealed that this NMR method is sensitive to the chemical cross‐link density whereas the gel content is also influenced by physical constraints such as entanglement. Furthermore, these copolymer networks show a shape‐memory effect, i.e. a temporary macroscopic shape can be programmed by heating the network above its glass transition temperature together with fixation during cooling. Reheating without fixation recovers the permanent shape. The recovery of the permanent shape could be followed by 1H DQ NMR buildup curves for a sample that was stretched by 80%.
Investigation of the Orientation in Composite Fibers of Polycarbonate with Multiwalled Carbon Nanotubes by Raman Microscopy
Authors: Fischer Dieter , Pötschke Petra , Brünig Harald , Janke Andreas 
Published: December 2005

AbstractThe superior association of the inherent good mechanical and electrical properties makes carbon nanotubes (CNT) exceptionally interesting for the production of composite fibers of thermoplastic polymers with CNT. Alignment of the CNT in the polymer fiber is important for improved mechanical properties. Especially the production of fibers makes it necessary to get a controlled orientation and/or alignment of the CNT. We applied transmission electron microscopy (TEM) and polarized Raman microscopy to quantify multiwalled carbon nanotubes (MWNT) orientation, alignment and crystallinity in polycarbonate (PC). The evaluation of the Raman measurements provided an improved alignment orientation of the MWNT in the fibers with increasing take‐up velocity during melt spinning and that the crystal structure of the MWNT is not changed through melt spinning.
Investigations on the Photoinitiator‐free Photopolymerization of Acrylates by Vibrational Spectroscopic Methods
Authors: Scherzer Tom , Knolle Wolfgang , Naumov Sergej , Prager Lutz 
Published: December 2005

AbstractPhotopolymerization of acrylates without photoinitiators was carried out by irradiation with short‐wavelength UV light from excimer lamps with an emission at 222 or 172 nm. Basic investigations on the reactivity of various acrylates and on the conditions under which they can be UV‐cured were performed by real‐time FTIR‐ATR spectroscopy. Depending on the molar extinction coefficients of a specific acrylate at the wavelength of irradiation, the absorption of the light within the coating leads to a pronounced intensity gradient which significantly influences polymerization rate and conversion. Accordingly, it limits the maximum thickness of the layer that can be cured (ranging from some hundreds of nanometres up to some micrometers). In addition to the basic studies, thin acrylate coatings were also cured on pilot scale. The actual conversion in the layer after UV irradiation was directly monitored by in‐line NIR reflection spectroscopy, and the resulting coatings were characterized by FTIR spectroscopy and hardness measurements.
Expression of peptidylarginine deiminase type 4 (PAD4) in various tumors
Authors: Chang Xiaotian , Han Jinxiang 
Published: December 2005

AbstractPeptidylarginine deiminase type 4 (PAD4/PADI4) posttranslationally converts peptidylarginine to citrulline, in a process known as citrullination. Evidence suggests that PAD4 plays an essential role in pathogenesis of rheumatoid arthritis (RA). RA synovium has many features in common with tumor tissues, including abnormal cell proliferation, extensive fibrin deposition, high coagulation activity, and extreme angiogenesis. The purpose of the present study was to investigate expression of PAD4 in various tumor tissues. Immunohistochemistry indicated that PAD4 had significant expression in many tumor tissues, especially various adenocarcinoma. Western blotting with anti PAD4 antibody and immunostaining with anti citrulline antibody confirmed the expression of the enzyme in these tumors. Furthermore, our immunohistochemistry also detected co‐location of PAD4 with cytokeratin (CK), a well‐known tumor marker for oncological study in many tumors. Western blot analysis also detected citrulline signals in CK extracted from the tumors. In addition, CK 8, 18, and 19 following in vitro citrullination resisted to the digestion of caspase. The results further confirm the expression of PAD4 in the tumors and support that PAD4 may contribute to the disrupted apoptosis of tumors by caspase‐mediated cleavage of CK. Double immunofluorescent labeling detected co‐location of PAD4 with CD34, a cell marker of heamatopoietic progenitor cells (HPC) in bone marrow and other normal tissues, as well as in some fibroblast‐like cells at stroma region of tumors, but not in the tumor cells. The findings imply that PAD4 is initially expressed in CD34+ cells of bone marrow and then distributed in derives of the multi‐potent progenitor cells in diverse tissues. The development of tumor cells expressing PAD4 is possibly associated with abnormal proliferation of CD34+ stem cells. © 2005 Wiley‐Liss, Inc.
Differentiated rabbit prostatic stromal cells in primary culture display functional α1A‐adrenoceptors
Authors: Boulbès Delphine , Choquet Armelle , Barrère‐Lemaire Stéphanie , Costa Pierre , Soustelle Laurent , Nargeot Joël , Bali Jean‐Pierre , Hollande Frédéric , Magous Richard 
Published: December 2005

AbstractAimsBPH is characterized by uncontrolled proliferation and increased contractility of prostatic smooth muscle cells. The activation of α1‐adrenoceptors (α1‐AR) seems involved in the latter event, but the lack of in vitro models expressing these receptors has hampered a more specific characterization of their role. In order to do so, we attempted to develop a new model of rabbit cultured prostatic stromal cells (PSC) in a non‐proliferative and differentiated state.MethodsThe expression of cytoskeletal and stromal markers was confirmed by immunohistochemistry on primary cultured PSC. α1‐AR subtype expression was assessed by RT‐PCR, while receptor coupling to the ERK1/ERK2 and calcium pathways was studied by Western Blot and Fura‐2 calcium imaging, respectively.ResultsCells grown under non‐proliferative conditions displayed a differentiated phenotype, with expression of contractile cytoskeletal and stromal proteins. Furthermore, the α1A‐AR was shown to activate ERK1/ERK2 as well as calcium signaling.ConclusionThese results emphasize the interest of this model for the characterization of PSC adrenergic regulation, in particular through the little‐known α1A‐AR. Neurourol. Urodynam. © 2005 Wiley‐Liss, Inc.
A general strategic capacity planning model under demand uncertainty
Authors: Huh Woonghee Tim , Roundy Robin O. , Çakanyildirim Metin 
Published: December 2005

AbstractCapacity planning decisions affect a significant portion of future revenue. In equipment intensive industries, these decisions usually need to be made in the presence of both highly volatile demand and long capacity installation lead times. For a multiple product case, we present a continuous‐time capacity planning model that addresses problems of realistic size and complexity found in current practice. Each product requires specific operations that can be performed by one or more tool groups. We consider a number of capacity allocation policies. We allow tool retirements in addition to purchases because the stochastic demand forecast for each product can be decreasing. We present a cluster‐based heuristic algorithm that can incorporate both variance reduction techniques from the simulation literature and the principles of a generalized maximum flow algorithm from the network optimization literature. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2006
Black hole search in common interconnection networks
Authors: Dobrev S. , Flocchini P. , Královič R. , Ružička P. , Prencipe G. , Santoro N. 
Published: December 2005

AbstractMobile agents operating in networked environments face threats from other agents as well as from the hosts (i.e., network sites) they visit. A black hole is a harmful host that destroys incoming agents without leaving any trace. To determine the location of such a harmful host is a dangerous but crucial task, called black hole search. The most important parameter for a solution strategy is the number of agents it requires (the size); the other parameter of interest is the total number of moves performed by the agents (the cost). It is known that at least two agents are needed; furthermore, with full topological knowledge, Ω(n log n) moves are required in arbitrary networks. The natural question is whether, in specific networks, it is possible to obtain (topology‐dependent but) more cost efficient solutions. It is known that this is not the case for rings. In this article, we show that this negative result does not generalizes. In fact, we present a general strategy that allows two agents to locate the black hole with O(n) moves in common interconnection networks: hypercubes, cube‐connected cycles, star graphs, wrapped butterflies, chordal rings, as well as in multidimensional meshes and tori of restricted diameter. These results hold even if the networks are anonymous. © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 47(2), 61–71 2006
A two‐dimensional stochastic algorithm for the solution of the non‐linear Poisson–Boltzmann equation: validation with finite‐difference benchmarks
Authors: Chatterjee Kausik , Poggie Jonathan 
Published: December 2005

AbstractThis paper presents a two‐dimensional floating random walk (FRW) algorithm for the solution of the non‐linear Poisson–Boltzmann (NPB) equation. In the past, the FRW method has not been applied to the solution of the NPB equation which can be attributed to the absence of analytical expressions for volumetric Green's functions. Previous studies using the FRW method have examined only the linearized Poisson–Boltzmann equation. No such linearization is needed for the present approach. Approximate volumetric Green's functions have been derived with the help of perturbation theory, and these expressions have been incorporated within the FRW framework. A unique advantage of this algorithm is that it requires no discretization of either the volume or the surface of the problem domains. Furthermore, each random walk is independent, so that the computational procedure is highly parallelizable. In our previous work, we have presented preliminary calculations for one‐dimensional and quasi‐one‐dimensional benchmark problems. In this paper, we present the detailed formulation of a two‐dimensional algorithm, along with extensive finite‐difference validation on fully two‐dimensional benchmark problems. The solution of the NPB equation has many interesting applications, including the modelling of plasma discharges, semiconductor device modelling and the modelling of biomolecular structures and dynamics. Copyright © 2005 John Wiley & Sons, Ltd.
Lower bound limit analysis of cohesive‐frictional materials using second‐order cone programming
Authors: Makrodimopoulos A. , Martin C. M. 
Published: December 2005

AbstractThe formulation of limit analysis by means of the finite element method leads to an optimization problem with a large number of variables and constraints. Here we present a method for obtaining strict lower bound solutions using second‐order cone programming (SOCP), for which efficient primal‐dual interior‐point algorithms have recently been developed. Following a review of previous work, we provide a brief introduction to SOCP and describe how lower bound limit analysis can be formulated in this way. Some methods for exploiting the data structure of the problem are also described, including an efficient strategy for detecting and removing linearly dependent constraints at the assembly stage. The benefits of employing SOCP are then illustrated with numerical examples. Through the use of an effective algorithm/software, very large optimization problems with up to 700 000 variables are solved in minutes on a desktop machine. The numerical examples concern plane strain conditions and the Mohr–Coulomb criterion, however we show that SOCP can also be applied to any other problem of lower bound limit analysis involving a yield function with a conic quadratic form (notable examples being the Drucker–Prager criterion in 2D or 3D, and Nielsen's criterion for plates). Copyright © 2005 John Wiley & Sons, Ltd.
A combined approach for goal‐oriented error estimation and adaptivity using operator‐customized finite element wavelets
Authors: Sudarshan R. , Amaratunga K. , Grätsch T. 
Published: December 2005

AbstractWe describe how wavelets constructed out of finite element interpolation functions provide a simple and convenient mechanism for both goal‐oriented error estimation and adaptivity in finite element analysis. This is done by posing an adaptive refinement problem as one of compactly representing a signal (the solution to the governing partial differential equation) in a multiresolution basis. To compress the solution in an efficient manner, we first approximately compute the details to be added to the solution on a coarse mesh in order to obtain the solution on a finer mesh (the estimation step) and then compute exactly the coefficients corresponding to only those basis functions contributing significantly to a functional of interest (the adaptation step). In this sense, therefore, the proposed approach is unified, since unlike many contemporary error estimation and adaptive refinement methods, the basis functions used for error estimation are the same as those used for adaptive refinement. We illustrate the application of the proposed technique for goal‐oriented error estimation and adaptivity for second and fourth‐order linear, elliptic PDEs and demonstrate its advantages over existing methods. Copyright © 2005 John Wiley & Sons, Ltd.
Analysis of adhesively bonded joints: a finite element method and a material model with damage
Authors: Schmidt Peter , Edlund Ulf 
Published: December 2005

AbstractThis paper deals with the derivation of a finite element (FE) method for an adhesively bonded joint which consists of two relatively thin bodies, joined by an even thinner adhesive layer. It is based on a model of the compound joint where the three bodies involved are described as material surfaces. A geometrically two‐dimensional model, where the middle surfaces of the upper and lower body are represented as geometrically coinciding surfaces, is obtained.An elastic–plastic material model with damage is used for the adhesive layer, and an important implication is that the (quasi‐static) propagation of the local failure zone in the adhesive layer in a structure can be simulated. Consequently, the failure load is obtained as a computational result and no failure criterion is needed.The problem is discretized, and a surface model, where only a single surface needs to be FE‐meshed, is obtained. A single‐lap joint is analysed and good agreement is obtained when compared to an analysis using a fine mesh with brick element. Furthermore, the failure load is computed and compared with experiments.The derived FE method opens up the possibility to efficiently model and analyse the mechanical behaviour of large bonded structures. Copyright © 2005 John Wiley & Sons, Ltd.
Efficient return algorithms for associated plasticity with multiple yield planes
Authors: Clausen J. , Damkilde L. , Andersen L. 
Published: December 2005

AbstractA new return method for implicit integration of linear isotropic yield criteria is presented. The basic idea is to perform all the manipulations in the principal stress space and thereby achieve very simple formulae for calculating the plastic corrector stresses, based on the constant gradient of such criteria. The return formulae are in closed form and no iteration is required. The method accounts for three types of stress return: return to a single yield plane, to a discontinuity line at the intersection of two yield planes and to a discontinuity point at the intersection between three or more yield planes. The infinitesimal and the consistent elastoplastic constitutive matrix are calculated for each type of stress return, as are the conditions to ascertain which type of return is required. The method is exemplified with the Mohr–Coulomb yield criterion. Copyright © 2005 John Wiley & Sons, Ltd.
Effect of intervention through a pharmaceutical care program on patient adherence with prescribed once‐daily atorvastatin
Authors: Vrijens Bernard , Belmans Ann , Matthys Katelijne , Klerk Erik de , Lesaffre Emmanuel 
Published: December 2005

AbstractAimsCorrect execution of prescribed dosing regimen(s) is essential for patients to benefit from lipid lowering treatments. The objective of this study was to estimate the effect of a pharmaceutical care program on the adherence of once‐daily atorvastatin treatment in patients with elevated cholesterol levels.MethodsIn both linguistic regions of Belgium, two districts were randomized between usual care and a supportive intervention program. Eligible patients included hyperlipemic subjects taking atorvastatin for at least 3 months. ‘Adherence’ was defined as the proportion of days during which the electronic device record showed that the patient had taken the daily dose. ‘Persistence’ quantifies how long the treatment is executed.ResultsA total of 392 patients from 35 pharmacies were included in the intent‐to‐treat (ITT) analysis of the data (194 patients received intervention and 198 in the control group). The intervention resulted in a 6.5% increase in post‐baseline adherence (p < 0.001) mainly driven by a 13% increase in persistence at 1 year (p = 0.002).ConclusionA supportive pharmaceutical care program consisting of review by patient and pharmacist of each patient's electronically compiled dosing history, plus educational reminders, improves patient adherence to the once‐daily atorvastatin dosing regimen, mainly by extending persistence. Copyright © 2005 John Wiley & Sons, Ltd.
Stereospecific polymerization of styrene with novel half‐sandwich titanium complexes—RCpTi(o‐MeOPhCPh2O)Cl2/methylaluminoxane
Authors: Chen Qihui , Huang Jiling 
Published: December 2005

AbstractTwo new half‐sandwich titanocene catalysts for the stereospecific polymerization of styrene, RCpTi(o‐MeOPhCPh2O)Cl2 (R = H (1); R = Me (2)), were prepared by reaction of the corresponding RCpTiCl3 complexes with o‐methoxyphenyldiphenylmethanol (o‐MeOPhCPh2OH) in the presence of triethylamine. Upon activation with excess methylaluminoxane (MAO), they showed high activities and high thermal stabilities for the stereospecific polymerization of styrene. The influences of polymerization temperature, Al/Ti molar ratio, solvent (aliphatic or aromatic) and time on the activity and syndiotacticity of the styrene polymerization were investigated. Copyright © 2006 Society of Chemical Industry
Synthesis of well‐defined polystyrene‐graft‐poly(methyl methacrylate)
Authors: Li Cuiping , Shi Yan , Fu Zhifeng 
Published: December 2005

AbstractA well‐defined graft copolymer, polystyrene‐graft‐poly(methyl methacrylate), was synthesized in two steps. In the first step, styrene and p‐vinyl benzene sulfonyl chloride were copolymerized via reversible addition–fragmentation chain transfer polymerization (RAFT) in benzene at 60 °C with 2‐(ethoxycarbonyl)prop‐2‐yl dithiobenzoate as a chain transfer agent and 2,2′‐azobis(isobutyronitrile) as an initiator. In the second step, poly[styrene‐co‐p‐(vinyl benzene sulfonyl chloride)] was used as a macroinitiator for the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in toluene at 80 °C with CuCl as a catalyst and 2,2′‐bipyridine as a ligand. With sulfonyl chloride groups as the initiating sites for the ATRP of MMA, high initiation efficiencies were obtained. Copyright © 2006 Society of Chemical Industry
Theoretical study of carbon atom scrambling in benzenium ions with ethyl or isopropyl groups
Authors: Arstad Bjørnar , Kolboe Stein , Swang Ole 
Published: December 2005

AbstractCarbon atom scrambling is observed in benzenium ions in the mass spectrometer and in isotopic labeling experiments in the methanol‐to‐hydrocarbons reaction over acidic zeolites. We have shown plausible scrambling mechanisms in ethyl‐ and isopropylbenzenium ions and various intramolecular interconversion reactions that may take place in alkylbenzenium ions. Quantum chemical Density Functional Theory (DFT) modeling at the B3LYP/cc‐pVTZ//B3LYP/6‐311G(d,p) level of theory has been carried out to investigate carbon atom scrambling reactions in ethyl‐ and isopropyl(methyl)benzenium ions. A total of 85 stationary points have been calculated (48 minima and 37 transition states). The carbon atom scrambling reactions start with an initial ring expansion of the benzenium ions to a seven‐membered ring. The seven‐membered ring may rearrange and at a later stage re‐contract to the original benzenium species, albeit with some atoms interchanged, i.e. there has been atom scrambling. Copyright © 2005 John Wiley & Sons, Ltd.