bluuebunny/crossref_metadata_2025_split huggingface dataset:
A rotation‐free shell triangle for the analysis of kinked and branching shells
Authors: Flores Fernando G. , Oñate Eugenio 
Published: August 2006

AbstractThis paper extends the capabilities of previous BST and EBST rotation‐free thin shell elements to the analysis of kinked and branching surfaces. The computation of the curvature tensor is first redefined in terms of the angle change between the normals at the adjacent elements. This allows to deal with arbitrary large angles between adjacent elements and to treat kinked surfaces. A relative stiffness between elements is introduced to consider non‐homogeneous surfaces. This idea is latter generalized to deal with branching shells. Several linear and non‐linear examples are presented showing that the formulation leads to the correct results. Copyright © 2006 John Wiley & Sons, Ltd.
The method of fundamental solutions for inverse source problems associated with the steady‐state heat conduction
Authors: Jin Bangti , Marin Liviu 
Published: August 2006

AbstractThis paper presents the use of the method of fundamental solutions (MFS) for recovering the heat source in steady‐state heat conduction problems from boundary temperature and heat flux measurements. It is well known that boundary data alone do not determine uniquely a general heat source and hence some a priori knowledge is assumed in order to guarantee the uniqueness of the solution. In the present study, the heat source is assumed to satisfy a second‐order partial differential equation on a physical basis, thereby transforming the problem into a fourth‐order partial differential equation, which can be conveniently solved using the MFS. Since the matrix arising from the MFS discretization is severely ill‐conditioned, a regularized solution is obtained by employing the truncated singular value decomposition, whilst the optimal regularization parameter is determined by the L‐curve criterion. Numerical results are presented for several two‐dimensional problems with both exact and noisy data. The sensitivity analysis with respect to two solution parameters, i.e. the number of source points and the distance between the fictitious and physical boundaries, and one problem parameter, i.e. the measure of the accessible part of the boundary, is also performed. The stability of the scheme with respect to the amount of noise added into the data is analysed. The numerical results obtained show that the proposed numerical algorithm is accurate, convergent, stable and computationally efficient for solving inverse source problems in steady‐state heat conduction. Copyright © 2006 John Wiley & Sons, Ltd.
A large deformation solid‐shell concept based on reduced integration with hourglass stabilization
Authors: Reese Stefanie 
Published: August 2006

AbstractIn this paper a new eight‐node (brick) solid‐shell finite element formulation based on the concept of reduced integration with hourglass stabilization is presented. The work focuses on static problems. The starting point of the derivation is the three‐field variational functional upon which meanwhile established 3D enhanced strain concepts are based. Important additional assumptions are made to transfer the approach into a powerful solid‐shell. First of all, a Taylor expansion of the first Piola–Kirchhoff stress tensor with respect to the normal through the centre of the element is carried out. In this way the stress becomes a linear function of the shell surface co‐ordinates whereas the dependence on the thickness co‐ordinate remains non‐linear. Secondly, the Jacobian matrix is replaced by its value in the centre of the element. These two assumptions lead to a computationally efficient shell element which requires only two Gauss points in the thickness direction (and one Gauss point in the plane of the shell element). Additionally three internal element degrees‐of‐freedom have to be determined to avoid thickness locking. One important advantage of the element is the fact that a fully three‐dimensional stress state can be modelled without any modification of the constitutive law. The formulation has only displacement degrees‐of‐freedom and the geometry in the thickness direction is correctly displayed. Copyright © 2006 John Wiley & Sons, Ltd.
Hybrid BEM for the early stage of unsteady transport process
Authors: Peratta Andrés , Popov Viktor 
Published: August 2006

AbstractThis paper presents a new approach for solving the early stage of 3D time‐dependent transport problems in non‐homogeneous fractured porous media in which the initial distribution of concentration presents discontinuous jump at the interface of two regions of transport properties differing in several orders of magnitude. The goal of this formulation is to overcome the problems of different scales and apparent large flux during early time by combining the 3D dual reciprocity boundary element method and a semi‐analytical solution of the time‐dependent advection–diffusion equation, employing a two‐level finite difference time integration scheme. Theoretical background, validation results and practical applications for the advection–diffusion equation in fractured and continuous porous media are reported. The results show advantages for relatively large‐scale models and complex geometries. Copyright © 2006 John Wiley & Sons, Ltd.
Crystallisation kinetics of novel branched poly(ethylene terephthalate): a small‐angle X‐ray scattering study
Authors: Hanley Tracey L , Forsythe John S , Sutton David , Moad Graeme , Burford Robert P , Knott Robert B 
Published: August 2006

AbstractThree types of poly(ethylene terephthalate) (PET) were investigated: linear (unprocessed) bottle‐grade PET (intrinsic viscosity, IV ∼ 0.82 dL g−1); a branched PET produced from linear PET by reactive extrusion with 0.4% w/w pyromellitic dianhydride and pentaerythritol in 5:1 molar ratio (IV ∼ 0.97 dL g−1); and a control sample produced from the same linear PET by extrusion under the same conditions without the reactive agents (IV ∼ 0.71 dL g−1). A key finding is that the reactive extrusion process, presumably as a consequence of branching and branch distribution, significantly modifies the crystallisation kinetics and changes the final morphology. Using small‐angle X‐ray scattering (SAXS) and differential scanning calorimetry (DSC), the crystallisation kinetics of PET was monitored from the melt (270 °C) to a crystallisation temperature of either 205 or 210 °C. The IV of the branched PET was ∼ 21% greater than that of the unprocessed PET, and the rate of melt crystallisation (from DSC measurements) was 510 s for the branched, 528 s for the control, and 640 s for the unprocessed PET. The lamellae spacings measured from the equilibrium SAXS patterns were ∼160 ± 10 Å for the branched PET and ∼180 ± 10 Å for the unprocessed PET. Such properties offer the potential for new applications requiring high‐melt‐strength PET. Copyright © 2006 Society of Chemical Industry
Structure and enzymatic properties of a chimeric bacteriophage RB69 DNA polymerase and single‐stranded DNA binding protein with increased processivity
Authors: Sun Siyang , Geng Linda , Shamoo Yousif 
Published: August 2006

AbstractIn vivo, replicative DNA polymerases are made more processive by their interactions with accessory proteins at the replication fork. Single‐stranded DNA binding protein (SSB) is an essential protein that binds tightly and cooperatively to single‐stranded DNA during replication to remove adventitious secondary structures and protect the exposed DNA from endogenous nucleases. Using information from high resolution structures and biochemical data, we have engineered a functional chimeric enzyme of the bacteriophage RB69 DNA polymerase and SSB with substantially increased processivity. Fusion of RB69 DNA polymerase with its cognate SSB via a short six amino acid linker increases affinity for primer‐template DNA by sixfold and subsequently increases processivity by sevenfold while maintaining fidelity. The crystal structure of this fusion protein was solved by a combination of multiwavelength anomalous diffraction and molecular replacement to 3.2 Å resolution and shows that RB69 SSB is positioned proximal to the N‐terminal domain of RB69 DNA polymerase near the template strand channel. The structural and biochemical data suggest that SSB interactions with DNA polymerase are transient and flexible, consistent with models of a dynamic replisome during elongation. Proteins 2006. © 2006 Wiley‐Liss, Inc.
A continuous‐flow crushing device for on‐line δ2H analysis of fluid inclusion water in speleothems
Authors: Vonhof Hubert B. , van Breukelen Martin R. , Postma Onno , Rowe Peter J. , Atkinson Tim C. , Kroon Dick 
Published: August 2006

AbstractA method for the isotope analysis of fluid inclusion water in speleothem calcite is presented. The technique is based on a commercially available continuous‐flow pyrolysis furnace (ThermoFinnigan TC‐EA). The main adaptation made to the standard TC‐EA configuration is the addition of a crusher and cold trap unit, which is connected to the carrier gas inlet at the top of the TC‐EA reactor tube. A series of tests conducted with this device shows that: (1) standard waters, injected in the crusher, and passed through a cryogenic trapping routine, yield accurate δ2H values; (2) crushed cubes of speleothem calcite from two Peruvian caves with rather dissimilar seepage water δ2H values yield fluid inclusion δ2H values in good accordance with these drip waters. The clear advantage of this continuous‐flow technique for fluid inclusion isotope analysis is that it is relatively quick compared with other techniques. Since the conditions of water sample introduction into the TC‐EA are identical for δ2H and δ18O analysis, we expect that only limited adaptations to the extraction procedure are required to provide δ18O analysis of fluid inclusion samples with the same device. Copyright © 2006 John Wiley & Sons, Ltd.
Rapid gas chromatography/mass spectrometry quinine determination in plasma after automated solid‐phase extraction
Authors: Damien Richard , Daval Sandrine , Souweine Bertrand , Deteix Patrice , Eschalier Alain , Coudoré François 
Published: August 2006

AbstractThe combined use of an automatic solid‐phase extraction (SPE) apparatus with Oasis MCX cartridges and gas chromatography/mass spectrometry (GC/MS) to rapidly quantify quinine in biological samples with cyproheptadine as the internal standard is described. The selected ion monitoring mode, with the quantification ions m/z 136 and 287 (qualifier ions: m/z 261, 381 and 215, 96), allows the estimation of quinine levels, respectively. Separation was completed within 12.7 min. Excellent linearity was found up to 10 000 µg/L of plasma. The limit of detection (LOD) was 12.2 µg/L and the limit of quantification (LOQ) was 40.6 µg/L. High reproducibility (intra‐assay CV range 1.9–4.3%, inter‐assay CV range 2.2–11.3%) and accuracy values (intra‐assay range 83.2–103.7%, inter‐assay range 86.8–103.7%) were obtained. Recoveries were concentration‐independent (97.2% and 89.8% for 4000 and 10 000 µg/L, respectively). This sensitive, simple assay for quinine in various matrices meets the current requirements for bioanalytical assays and may be used to monitor quinine levels in patients developing severe malaria with acute renal failure during hemofiltration. The optimal quinine dose in this situation is not really established and to improve clinical care, quinine concentrations might be explored to improve efficacy and minimise potential toxicity. Copyright © 2006 John Wiley & Sons, Ltd.
Biotransformation of the triketone herbicide mesotrione by a Bacillus strain. Metabolite profiling using liquid chromatography/electrospray ionization quadrupole time‐of‐flight mass spectrometry
Authors: Durand Stéphanie , Légeret Bertrand , Martin Anne‐Sophie , Sancelme Martine , Delort Anne‐Marie , Besse‐Hoggan Pascale , Combourieu Bruno 
Published: August 2006

AbstractThe metabolic pathway involved in the biotransformation of the herbicide mesotrione by the bacterial strain Bacillus sp. 3B6 was investigated by a reliable liquid chromatography/electrospray ionization quadrupole time‐of‐flight mass spectrometry (LC/ESI‐QTOF‐MS) method. The LC/ESI‐MS method, both in positive and negative mode, with the assistance of MS2 fragments and isotopic pattern analyses, allowed us to identify five metabolites. This work constitutes the first complete monitoring of mesotrione degradation kinetics. Among the transformation products found by both techniques, one was formed by intramolecular cyclization between a hydroxylamine and a keto function, which is quite a rare biological reactivity process. For each identified metabolite, a fragmentation pathway is proposed for negative and positive mode. Copyright © 2006 John Wiley & Sons, Ltd.
Unimolecular dissociation of protonated trans‐1,4‐diphenyl‐2‐butene‐1,4‐dione in the gas phase: rearrangement versus simple cleavage
Authors: Wu Lianming , Liu David Q. , Vogt Frederick G. 
Published: August 2006

AbstractFragmentation mechanisms of trans‐1,4‐diphenyl‐2‐butene‐1,4‐dione were studied using a variety of mass spectrometric techniques. The major fragmentation pathways occur by various rearrangements by loss of H2O, CO, H2O and CO, and CO2. The other fragmentation pathways via simple alpha cleavages were also observed but accounted for the minor dissociation channels in both a two‐dimensional (2‐D) linear ion trap and a quadrupole time‐of‐flight (Q‐TOF) mass spectrometer. The elimination of CO2 (rather than CH3CHO or C3H8), which was confirmed by an exact mass measurement using the Q‐TOF instrument, represented a major fragmentation pathway in the 2‐D linear ion trap mass spectrometer. However, the elimination of H2O and CO becomes more competitive in the beam‐type Q‐TOF instrument. The loss of CO is observed in both the MS2 experiment of m/z 237 and the MS3 experiment of m/z 219 but via the different transition states. The data suggest that the olefinic double bond in protonated trans‐1,4‐diphenyl‐2‐butene‐1,4‐dione plays a key role in stabilizing the rearrangement transition states and increasing the bond dissociation (cleavage) energy to give favorable rearrangement fragmentation pathways. Copyright © 2006 John Wiley & Sons, Ltd.
Electrospray droplet impact/secondary ion mass spectrometry: cluster ion formation
Authors: Mori Kunihiko , Asakawa Daiki , Sunner Jan , Hiraoka Kenzo 
Published: August 2006

AbstractThe electrospray droplets that are sampled through an orifice into the vacuum chamber are accelerated by 10 kV and impact on the stainless steel substrate. The mass and the kinetic energy of electrospray droplets are roughly estimated to be a few 106 u and ∼106 eV, respectively. The molecular ion M+. and the protonated molecule [M+H]+ are observed as secondary ions for chrysene and coronene deposited on the metal substrate (no matrix used). The ionization may take place in the shock wave generated by the high‐momentum coherent collision between the droplet projectile and the solid sample. Cluster ions of H+(H2O)n and CF3COO−(H2O)n, with n up to ∼150, were observed as secondary ions formed by the electrospray droplet impact ionization (EDI) for 10−2 M trifluoroacetic acid (TFA) aqueous solution. This indicates that the charged droplets that collide with the metal substrate with the kinetic energy of ∼106 eV do not vaporize completely but are disintegrated into many tiny microdroplets. The ion signal intensity anomalies (i.e. magic numbers) were observed for the cluster ions of H3O+(H2O)n and CF3COO−(H2O)n for 10−2 M TFA aqueous solution and of Cs+(H2O)n, I−(H2O)n, Cs+(CsI)n, and I−(CsI)n for 10−2 M CsI aqueous solution. Copyright © 2006 John Wiley & Sons, Ltd.
Large deviations for mean field models of probabilistic cellular automata
Authors: Balister P. , Bollobás B. , Kozma R. 
Published: August 2006

AbstractProbabilistic cellular automata form a very large and general class of stochastic processes. These automata exhibit a wide range of complex behavior and are of interest in a number of fields of study, including mathematical physics, percolation theory, computer science, and neurobiology. Very little has been proved about these models, even in simple cases, so it is common to compare the models to mean field models. It is normally assumed that mean field models are essentially trivial. However, we show here that even the mean field models can exhibit surprising behavior. We prove some rigorous results on mean field models, including the existence of a surrogate for the “energy” in certain non‐reversible models. We also briefly discuss some differences that occur between the mean field and lattice models. © 2006 Wiley Periodicals, Inc. Random Struct. Alg., 2006
Behavioral assumptions and theory development: the case of transaction cost economics
Authors: Tsang Eric W. K. 
Published: August 2006

AbstractFrom a critical realist perspective, I discuss the role played by behavioral assumptions in organization theories, and use transaction cost economics as an illustrative example. Core behavioral assumptions often constitute the foundation of the mechanismic explanations of a theory, and thus should play a pivotal role in theory development. I distinguish between assumption‐based and assumption‐omitted theory testing, and show that empirical research in transaction cost economics has been dominated by assumption‐omitted testing. To establish a solid foundation for a new theory, management researchers should pay more attention to assumption‐based testing. Copyright © 2006 John Wiley & Sons, Ltd.
What to do next? The case for non‐predictive strategy
Authors: Wiltbank Robert , Dew Nicholas , Read Stuart , Sarasvathy Saras D. 
Published: August 2006

AbstractTwo prescriptions dominate the topic of what firms should do next in uncertain situations: planning approaches and adaptive approaches. These differ primarily on the appropriate role of prediction in the decision process. Prediction is a central issue in strategy making owing to the presumption that what can be predicted can be controlled. In this paper we argue for the independence of prediction and control. This implies that the pursuit of successful outcomes can occur through control‐oriented approaches that may essentially be non‐predictive. We further develop and highlight control‐oriented approaches with particular emphasis on the question of what organizations should do next. We also explore how these approaches may impact the costs and risks of firm strategies as well as the firm's continual efforts to innovate. Copyright © 2006 John Wiley & Sons, Ltd.
Synthese, Kristallstruktur und magnetisches Verhalten von [Gd2(ClF2CCOO)6(H2O)2(bipy)2]2·C2H5OH
Authors: John Daniela , Urland Werner 
Published: August 2006

AbstractSingle crystals of [Gd2(ClF2CCOO)6(H2O)2(bipy)2]2· C2H5OH have been obtained by reaction of Gd(ClF2CCOO)3(H2O)3 with 2,2′‐bipyridyl in a solution of ethanol and water. The compound crystallizes in the triclinic space group $P{\bar 1}$ (Nr. 2, Z = 2, a = 1201.6(2) pm, b = 1241.1(3) pm, c = 1990.4(3) pm, α = 96.29(2)°, β = 104.85(2)°, γ = 116.70(2)°). The Gd3+ ions are bridged by carboxylate groups to dimers and are eightfold coordinated by six oxygen and two nitrogen atoms. The magnetic behaviour of the compound was investigated in the temperature range of 1.77 to 300 K. The magnetic data indicate an antiferromagnetic interaction within the dimeric units.
Zur Kristallchemie der Oxoruthenate
Authors: Müller‐Buschbaum Hanskarl 
Published: August 2006

AbstractDer Übersichtsbeitrag systematisiert die Kristallchemie der Oxoruthenate. Ruthenium zeigt überwiegend oktaedrische Sauerstoffumgebung. Daneben sind in einigen Fällen RuO4‐Tetraeder, tetragonale RuO5‐Pyramiden, trigonale RuO5‐Bipyramiden und planare RuO4‐Polygone beobachtet worden. Ein Maß der Ordnung von Kristallstrukturen der Oxoruthenate ist die steigende Verknüpfung von RuO6‐Oktaedern, ausgehend von zueinander isolierten, zu kondensierten Oktaedern vom Typ Ru2O9 und Ru3O12, gefolgt von $^{1}_{\infty}\rm [RuO_{3}]$‐, $^{1}_{\infty}\rm [RuO_{4}]$‐ und $^{1}_{\infty}\rm [RuO_{5}]$‐Ketten, Ringstrukturen, ebenen und gewellten Netzen bis hin zu Tunnelstrukturen und dreidimensionalen Netzwerken. Ein Teil des Übersichtsbeitrags befaßt sich mit der Stapelung von MO6‐Oktaedern, Ru2O9‐Oktaederdoppeln, Ru3O12‐Oktaedertripeln (Stapelvarianten), Varianten der Perowskite im weitesten Sinne und Varianten des K2NiF4‐Typs (Ruddlesden‐Popper‐Phasen). Schlußendlich wird über zwei Clusterverbindungen (Al0,68RuSn6O8; Sn15Ru3O14) berichtet, die keine Sauerstoffumgebung des Rutheniums aufweisen.In den vorgestellten Oxoruthenaten zeigt Ruthenium ein breites Spektrum von Oxidationszahlen, die von Ru3+ bis Ru7+ reichen. In einigen Verbindungen besetzt Ruthenium nur eine Punktlage. In Kombination mit Elementen mit eindeutiger Wertigkeit zeigt Ruthenium gebrochene Ladungen wie Ru4,5+; Ru5,33+ oder Ru5,75+. Andere Beispiele zeigen Ruthenium auf unterschiedlichen Punklagen, aber dennoch mit gemischter Valenz. In solchen Fällen wurden Berechnungen der partiellen Coulomb‐Terme der Gitterenergie herangezogen, um zwischen möglichen unterschiedlichen Ladungszahlen des Rutheniums zu unterscheiden.
Nb2Cl10(P4S10)2: A Co‐Crystal of Nb2Cl10 and P4S10
Authors: Pfitzner Arno , Hoppe Diana 
Published: August 2006

AbstractRed moisture—sensitive crystals of Nb2Cl10(P4S10)2 were obtained from a solution of P4S10 and Nb2Cl10 in CS2. Nb2Cl10(P4S10)2 crystallises in the space group $P{\bar 1}$ with a = 9.577(2), b = 10.894(2), c = 11.477(2) Å, α = 71.40(1), β = 68.14(1), γ = 67.58(1)°; V = 1005.2(3) Å3, Z = 2. In the crystal structure molecules of P4S10 and Nb2Cl10 are arranged similar to the packing of the ions in the CaF2 structure type. A comparison of the Raman spectrum of Nb2Cl10(P4S10)2 with spectra of the corresponding reactants indicates that no significant bonds are present between both components of the title compound. Therefore, Nb2Cl10(P4S10)2 has to be considered as a co‐crystal of the starting materials. Ta2Cl10(P4S10)2 is isotypic with Nb2Cl10(P4S10)2, the lattice constants are a = 9.643(3), b = 10.963(3), c = 11.572(4) Å; α = 71.54(2), β = 68.11(2), γ = 67.61(2)°.
EYPHKAMEN: Ln‐Oktaedertripel in Ln14(C2)3I20 mit Ln = La, Ce
Authors: Mattausch Hansjürgen , Simon Arndt , Kienle Lorenz , Hoch Constantin , Zheng Chong , Kremer Reinhard K. 
Published: August 2006

AbstractEYPHKAMEN: Ln Octahedron Triples in Ln14(C2)3I20 with Ln = La, Ce The compounds Ln14(C2)3I20 (Ln = La, Ce) are prepared from Ln, LnI3, and C molar ratio (11:10:9) at 920 °C (Ce) and 930 °C (La) as pure phases, forming polygonal black crystals with a greenish lustre which are moisture and air sensitive. They are isotypic and crystallize in the triclinic system, $P{\bar 1}$, with lattice parameters a = 9.761(1) Å, b = 11.790(1) Å, c = 14.055(1) Å, α = 79.60(1)°, β = 71.49(1)°, γ = 65.79(1)° (La14(C2)3I20) and a = 9.688(1) Å, b = 11.670(1) Å, c = 13.932(1) Å, α = 80.16(1)°, β = 71.81(1)°, γ = 65.88(1)° (Ce14(C2)3I20). In the crystal structure the Ln atoms form Ln6 octahedra centered by C2‐groups. Three octahedra are condensed to the triples ((Ln2Ln2Ln2/2C2)2(Ln2Ln4/2C2). The iodine atoms coordinate the octahedra above all free edges as in a M6X12‐type cluster. The mean C‐C distance in the C2 unit is 1.39Å. HRTEM images of crystals selected from different batches prepared at lower temperature show clusters of different lengths besides the triple octahedra. Ce14(C2)3I20 is a semiconductor and has an effective magnetic moment of 2.38 μB.