bluuebunny/crossref_metadata_2025 huggingface dataset:
In‐Vitro Hemocompatibility Evaluation of a Thermoplastic Polyurethane Membrane with Surface‐Immobilized Water‐Soluble Chitosan and Heparin
Authors: Lin Wen‐Ching , Tseng Chien‐Hao , Yang Ming‐Chien
Published: October 2005

Summary: The surface of a thermoplastic polyurethane (TPU) membrane was treated with low temperature plasma (LTP) and was then grafted with poly(acrylic acid) (PAA), followed by the grafting of water‐soluble chitosan (WSC) and heparin (HEP). The surface was characterized with static contact‐angle and X‐ray photoelectron spectroscopy (XPS). The results showed that the surface densities of peroxides and PAA reached a maximum when treated with LTP for 90 s. A higher pH of the reacting solution led to higher graft densities of WSC and HEP. After WSC and HEP grafting, the hydrophilicity of the TPU membrane was increased. The adsorption of proteins on HEP‐grafted TPU membranes was effectively curtailed. In addition, HEP grafting also reduced platelet adhesion, elevated thrombin inactivation, and prolonged the blood coagulation time. According to the L929 fibroblast cell growth inhibition index, the HEP‐grafted TPU membranes exhibited non‐cytotoxicity. Overall results demonstrated that the HEP immobilization could not only improve the hydrophilicity but also the hemocompatibility of the TPU membrane, while maintaining the ascendant biocompatibility.

The APTT inversely varied with the platelet adhesion for the modified TPU membranes studied here.

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The APTT inversely varied with the platelet adhesion for the modified TPU membranes studied here.
Microstructure Formation and Property of Chitosan‐Poly(acrylic acid) Nanoparticles Prepared by Macromolecular Complex
Authors: Chen Qi , Hu Yong , Chen Ying , Jiang Xiqun , Yang Yonghua
Published: October 2005

Summary: We report here a study on the microstructure formation process of polymeric nanoparticles based on polyelectrolyte complexes. When polyanion poly(acrylic acid) (PAA) was dropped into polycation chitosan (CS) solution, CS‐PAA nanoparticles with diverse microstructure would be formed under different experimental conditions. The microstructure of CS‐PAA nanoparticles changed from solid spherical nanoparticles to core‐shell separative ones and turned back to solid spherical ones with the variation of preparation conditions. The influence of molecular weight of CS and PAA, shell cross‐linking, dropping temperature on the size, stability and morphology of CS‐PAA nanoparticles were also studied. The nanoparticle size was affected by the molecular weight of CS and PAA, the ratio of amino group to carboxyl group (na/nc) and the incubation temperature as well. The shell‐cross‐linking provides a means to stabilize these nanoparticles. These nanoparticles can encapsulate plasmid DNA very well, which makes them have great potential in gene delivery.

Microstructure of non‐cross‐linked CS‐PAA nanoparticles, encapsulated plasmid DNA, at various na/nc.

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Microstructure of non‐cross‐linked CS‐PAA nanoparticles, encapsulated plasmid DNA, at various na/nc.
Some general ansätze for the Lanczos potential spinor
Authors: Illge Reinhard
Published: September 2005

The Weyl curvature spinor of every four‐dimensional spacetime is derivable from a potential spinor, called the Lanczos potential. In certain special situations the Lanczos spinor has been found explicitly, but there exists no algorithm for finding it in general. Using a modified Newman–Penrose formalism proposed by Wünsch, we study some ansätze as candidates for the Lanczos potential with respect to an arbitrary spin frame. We show under which necessary and sufficient conditions each ansatz will lead to a Lanczos potential of theWeyl spinor. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On Descartes' rules of signs and their exactness
Authors: Peña J. M.
Published: September 2005

This paper revisits the Descartes' rules of signs and provides new bounds for the number of complex roots of a polynomial in certain complex regions. We also prove that the Descartes' rules associated with the Bernstein basis are exact for polynomials whose roots are real. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Local well‐posedness and blow‐up criteria of solutions for a rod equation
Authors: Zhou Yong
Published: September 2005

In this paper we consider a new rod equation derived recently by Dai [Acta Mech. 127 No. 1–4, 193–207 (1998)] for a compressible hyperelastic material. We establish local well‐posedness for regular initial data and explore various sufficient conditions of the initial data which guarantee the blow‐up in finite time both for periodic and non‐periodic case. Moreover, the blow‐up time and blow‐up rate are given explicitly. Some interesting examples are given also. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the uniqueness of the solution of the two‐dimensional Navier–Stokes equation with a Dirac mass as initial vorticity
Authors: Gallagher Isabelle , Gallay Thierry , Lions Pierre‐Louis
Published: September 2005

We propose two different proofs of the fact that Oseen's vortex is the unique solution of the two‐dimensional Navier–Stokes equation with a Dirac mass as initial vorticity. The first argument, due to C. E. Wayne and the second named author, is based on an entropy estimate for the vorticity equation in self‐similar variables. The second proof is new and relies on symmetrization techniques for parabolic equations. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Provisional diagnostic criteria for depression in Parkinson's disease: Report of an NINDS/NIMH Work Group
Authors: Marsh Laura , McDonald William M. , Cummings Jeffrey , Ravina Bernard ,   NINDS/NIMH Work Group on Depression and Parkinson's Disease
Published: October 2005

Mood disorders are the most common psychiatric problem associated with Parkinson's disease (PD), and have a negative impact on disability and quality of life. Accurate diagnosis of depressive disturbances in PD is critical and will facilitate the testing and use of new interventions; however, there are no clear diagnostic criteria for depressive disorders in PD. In their current form, strict Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria are difficult to use in PD and require attribution of specific symptoms to PD itself or the depressive syndrome. Additionally, DSM criteria for major depression and dysthymia exclude perhaps half of PD patients with comorbid clinically significant depression. This review summarizes an NIH‐sponsored workshop and describes recommended changes to DSM diagnostic criteria for depression for use in PD. Participants also recommended: (1) an inclusive approach to symptom assessment to enhance reliability of ratings in PD and avoid the need to attribute symptoms to a particular cause; (2) the inclusion of subsyndromal depression in clinical research studies of depression of PD; (3) the specification of timing of assessments for PD patients with motor fluctuations; and (4) the use of informants for cognitively impaired patients. The proposed diagnostic criteria are provisional and intended to be defined further and validated but provide a common starting point for clinical research in PD‐associated depression. © 2005 Movement Disorder Society
Some solutions for the spin glass system and for systems originating from it
Authors: Łada Andrzej
Published: October 2005

For the spin glass system the solutions, u = νΦ and u = νx/|x| are considered, where ν is a scalar function and Φεℝ3 is constant. For a system originating from the spin glass one, a solution u = tan[q(|x|/t)]x/|x| is considered.
Remarks on non‐trivial solutions of a Volterra integral equation
Authors: Okrasiński W.
Published: October 2005

In this paper non‐linear integral equations describing shock wave phenomena are presented. Some necessary and sufficient conditions for the existence of non‐trivial solutions to equations of this type are given.
An integral operator related to the Stokes system in exterior domains
Authors: Deuring Paul
Published: October 2005

Consider a bounded domain Ω in ℝ3 with C2‐boundary ∂Ω. In [1] the Stokes problem in the exterior domain ℝ3/Ω, with resolvent parameter [λϵℂ\] − [∞,0], is solved by using the method of integral equations. However, for estimating the corresponding solutions in Lp norms, it turns out that a certain operator defined on the spaces Lr(∂Ω)3, for r ϵ]1, ∞[, has to be evaluated in the norm of Lr(∂Ω)3. This estimate is proved in the present paper.
Higher moments for kinetic equations: The Vlasov–Poisson and Fokker–Planck cases
Authors: Perthame B.
Published: October 2005

Let us consider a solution f(x,v,t)ϵL1(ℝ2N × [0,T]) of the kinetic equation
equation image
where |v|α+1 fo,|v|α ϵL1 (ℝ2N × [0, T]) for some α< 0. We prove that f has a higher moment than what is expected. Namely, for any bounded set Kx, we have
equation image
We use this result to improve the regularity of the local density ρ(x,t) = ∫ƒdν for the Vlasov–Poisson equation, which corresponds to g = Eƒ, where E is the force field created by the repartition ƒ itself. We also apply this to the Bhatnagar‐Gross‐;Krook model with an external force, and we prove that the solution of the Fokker‐Pianck equation with a source term in L2 belongs to L2([0, T]; H1/2(ℝ)).
On global solvability of non‐linear viscoelastic equations in the analytic category
Authors: D'Ancona Piero , Shibata Yoshihiro
Published: October 2005

We prove the global existence of analytic solutions to the non‐linear viscoelastic equations of the following type:

where ϕ and ψ are continuous and non‐negative functions satisfying some additional conditions. The method of the analytic energy estimates is used.
Spectral theory and L∞‐time decay estimates for Klein–Gordon equations on two half axes with transmission: The tunnel effect
Authors: Mehmeti Felix Ali
Published: October 2005

Consider two copies N1, N2 of the interval [0, ∞]. Consider Klein‐Gordon equations with (different) constant coefficients on ℝ × Nj ( = time × space). Assume the coincidence of the values of the solution at the boundary points of the Nj for all times and a transmission condition relating its first (one‐sided) space derivatives at these points.

Under a symmetry condition, we extend the spatial part of the equation and the transmission conditions to a self‐adjoint operator (by Friedrichs extension) and reformulate our problem in terms of an abstract wave equation in a suitable Hilbert space. We derive an expansion of the solution in generalized eigenfunctions of this self‐adjoint extension and show, that the L∞‐norms (in space) of the solution and its first k space derivatives at the time t decay for t → ∞ at least as const. t¼, if the initial conditions satisfy a compatibility condition of order k derived in this paper. The loss of decay rate in comparison with the full line case (const. t−½, cf. [28]) is caused by the tunnel effect.

Further we show that an abstract wave equation in a Hilbert space with a Friedrichs extension as spatial part can always be derived from a stationarity principle for an associated action‐type functional. This yields a physical legitimation of our model by the principle of stationary action and moreover a criterion for the physical interpretability of all models created by the linear interaction concept [4, 6, 8, 10], in particular for the coupling of media of different dimension (alternative to [13, 16] for similar models).
On the initial value problem for the Vlasov‐Poisson‐Fokker‐Planck system with initial data in Lp spaces
Authors: Carrillo José A. , Soler Juan
Published: October 2005

In this paper the global existence of weak solutions for the Vlasov‐Poisson‐Fokker‐Planck equations in three dimensions is proved with an L1 ∩ Lp initial data. Also, the global existence of weak solutions in four dimensions with small initial data is studied. A convergence of the solutions is obtained to those built by E. Horst and R. Hunze when the Fokker‐Planck term vanishes. In order to obtain the a priori necessary estimates a sequence of approximate problems is introduced. This sequence is obtained starting from a non‐linear regulation of the problem together with a linearization via a time retarded mollification of the non‐linear term. The a priori bounds are reached by means of the control of the kinetic energy in the approximate sequence of problems. Then, the proof is completed obtaining the equicontinuity properties which allow to pass to the limit.
An explicit solution of the pseudo‐hyperbolic initial boundary value problem in a multiply connected region
Authors: Krutitskii Pavel A.
Published: October 2005

An explicit solution of the pseudo‐hyperbolic initial boundary value problem with a mixed boundary condition has been constructed. The problem describes the propagation of non‐stationary internal waves in a stratified and rotational fluid. The generation of waves is caused by small oscillations of double‐sided plates beginning at time t = 0. Dynamic pressure is specified on one set of plates and this yields the first boundary condition. Normal velocities are specified on another set of plates and this leads to an analogue of the second boundary condition with time derivatives. The solution has been obtained by the method of non‐classical time‐dependent dynamic potentials. The uniqueness of the solution has been studied.
Traces of Sobolev functions with one square integrable directional derivative
Authors: Gregoratti M.
Published: September 2005

We consider the Sobolev spaces of square integrable functions v, from ℝn or from one of its hyperquadrants Q, into a complex separable Hilbert space, with square integrable sum of derivatives ∑∂𝓁v. In these spaces we define closed trace operators on the boundaries ∂Q and on the hyperplanes {r𝓁 = z}, z ∈ ℝ\{0}, which turn out to be possibly unbounded with respect to the usual L2‐norm for the image. Therefore, we also introduce bigger trace spaces with weaker norms which allow to get bounded trace operators, and, even if these traces are not L2, we prove an integration by parts formula on each hyperquadrant Q. Then we discuss surjectivity of our trace operators and we establish the relation between the regularity properties of a function on ℝn and the regularity properties of its restrictions to the hyperquadrants Q. Copyright © 2005 John Wiley & Sons, Ltd.
Patterning by genetic networks
Authors: Genieys S. , Vakulenko S.
Published: September 2005

We consider here the morphogenesis (pattern formation) problem for some genetic network models. First, we show that any given spatio‐temporal pattern can be generated by a genetic network involving a sufficiently large number of genes. Moreover, patterning process can be performed by an effective algorithm. We also show that Turing's or Meinhardt's type reaction–diffusion models can be approximated by genetic networks.

These results exploit the fundamental fact that the genes form functional units and are organized in blocks. Due to this modular organization, the genes always are capable to construct any new patterns and even any time sequences of new patterns from old patterns. Computer simulations illustrate some analytical results. Copyright © 2005 John Wiley & Sons, Ltd.
Markets for surplus components with a strategic supplier
Authors: Dong Lingxiu , Durbin Erik
Published: September 2005

We study markets for surplus components, which allow manufacturers with excess component inventory to sell to firms with a shortage. Recent developments in internet commerce have the potential to greatly increase the efficiency of such markets. We develop a one‐period model in which a monopolist supplier sells to a number of independent manufacturers who are uncertain about demand for final goods. After uncertainty is resolved, the manufacturers have the opportunity to trade. Because uncertainty is over demand functions, the model allows us to endogenize both the price of final goods and the price of components in wholesale and surplus markets. We derive conditions on demand uncertainty that determine whether a surplus market will increase or decrease supplier profits. Increased costs of transacting on the surplus market may benefit manufacturers, because of the impact of these costs on the supplier's pricing power. The surplus market can decrease overall efficiency of the supply chain, since the benefit of better allocation of components may be outweighed by an increased double‐marginalization effect. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.
Large deflection analysis of elastic space membranes
Authors: Tsiatas G. C. , Katsikadelis J. T.
Published: October 2005

In this paper a solution to the problem of elastic space (initially non‐flat) membranes is presented. A new formulation of the governing differential equations is presented in terms of the displacements in the Cartesian co‐ordinates. The reference surface of the membrane is the minimal surface. The problem is solved by direct integration of the differential equations using the analogue equation method (AEM). According to this method the three coupled non‐linear partial differential equations with variable coefficients are replaced with three uncoupled equivalent linear flat membrane equations (Poisson's equations) subjected to unknown sources under the same boundary conditions. Subsequently, the unknown sources are established using a procedure based on the BEM. The displacements as well as the stress resultants are evaluated at any point of the membrane from their integral representations of the solution of the substitute problems, which are used as mathematical formulae. Several membranes are analysed which illustrate the method and demonstrate its efficiency and accuracy as compared with analytical and existing numerical methods. Copyright © 2005 John Wiley & Sons, Ltd.
Numerical experiments with the Bloch–Floquet approach in homogenization
Authors: Conca C. , Natesan S. , Vanninathan M.
Published: October 2005

This paper deals with a numerical study of classical homogenization of elliptic linear operators with periodic oscillating coefficients (period εY). The importance of such problems in engineering applications is quite well‐known. A method introduced by Conca and Vanninathan [SIAM J. Appl. Math.1997;57:1639–1659] based on Bloch waves that homogenize this kind of operators is used for the numerical approximation of their solutionuε. The novelty of their approach consists of using the spectral decomposition of the operator on ℝNto obtain a new approximation ofuε—the so‐called Bloch approximation θε—which provides an alternative to the classical two‐scale expansionuε(x)=u*(x)+Σεkuk(x,x/ε), and therefore, θεcontains implicitly at least the homogenized solutionu* and the first‐ and second‐order corrector terms.

The Bloch approximation θεis obtained by computing, for every value of the Bloch variable η in the reciprocal cellY′ (Brillouin zone), the components ofu* on the first Bloch mode associated with the periodic structure of the medium. Though theoretical basis of the method already exists, there is no evidence of its numerical performance. The main goal of this paper is to report on some numerical experiments including a comparative study between both the classical and Bloch approaches. The important conclusion emerging from the numerical results states that θεis closer touε, i.e. is a better approximation ofuεthan the first‐ and second‐order corrector terms, specifically in the case of high‐contrast materials. Copyright © 2005 John Wiley & Sons, Ltd.
Delamination buckling of laminated plates
Authors: Mukherjee Yu Xie , Xie Zhicheng , Ingraffea Anthony R.
Published: October 2005

The subject of this paper is the buckling of laminated plates, with a pre‐existing delamination, subjected to in‐plane loading. Each laminate is modelled as an orthotropic Mindlin plate. The analysis is carried out by a combination of the finite element and asymptotic expansion methods. By applying the finite element method, plates with general delamination regions can be studied. The asymptotic expansion method reduces the number of unknown variables of the eigenvalue equation to that of the equation for a single Kirchhoff plate. Numerical results for the critical buckling load are presented for several examples. The effects of the shape, size and position of the delamination on the buckling load are studied through these examples.
Syntheses and nickel coordination properties of cyclen substituted with mixed stilbene/poly(ethylene glycol) dendritic arms
Authors: Weng Jian , Zhang Qiqing
Published: September 2005

We synthesized a series of cyclens substituted with mixed stilbene and poly(ethylene glycol) dendritic arms. All dendrimers terminated with different peripheral groups had good solubility in common organic solvents, and dendrimers terminated with CO2H groups (CO2H‐dendrimers) were also soluble in alkaline solutions. The nickel coordination properties of these dendrimers were investigated in organic solvents. Dendrimers terminated with CN groups (CN‐dendrimers) and the second‐generation CO2H‐dendrimer [(CO2H)8L2] could produce pentacoordinated nickel complexes; the third‐generation CO2H‐dendrimer [(CO2H)16L3] could form tetra‐ and pentacoordinated nickel complexes, and the nickel complex of the fourth‐generation CO2H‐dendrimer [(CO2H)32L4] could not be obtained. This result was due to the fact that the globular surface of (CO2H)16L3 formed a hydrogen‐bond network that selectively penetrated cations and inhibited the access of anions to the core. The formation of the hydrogen‐bond network was confirmed by Fourier transform infrared, 1H NMR, and fluorescence data. The CN‐dendrimers could not form hydrogen bonds on the surface, and the first‐ and second‐generation CO2H‐dendrimers could not form intramolecular hydrogen‐bond networks. Therefore, they had no selectivity for positive nickel ions and negative chloride ions. (CO2H)32L4 could not produce a nickel complex because it had a crammed backbone structure that could not penetrate nickel and chloride ions. Therefore, it was possible to control the ion access of cations and anions with the hydrogen‐bond network of (CO2H)16L3. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5414–5428, 2005
Simultaneous construction of polymer backbone and side chains by three‐component polycondensation. Synthesis of polyethers with propargyl side chains from dialdehydes, alkylene bis(trimethylsilyl) ethers, and allenyltrimethylsilane
Authors: Niimi Lui , Hiraoka Shuichi , Yokozawa Tsutomu
Published: September 2005

Polyethers with propargyl side chains were synthesized by the acid‐catalyzed reaction of dialdehydes 1, alkylene bis(trimethylsilyl) ethers 2, and allenyltrimethylsilane 4. When ethylene glycol bis(trimethylsilyl) ether was used as 2, only oligomer was obtained. However, the use of 2 with longer carbon chains gave the desired polyethers consisting of 1, 2, and 4 in the molar ratio 1:1:2 in good yields in the presence of 10 mol % triphenylmethyl perchlorate (TrClO4) at −20 °C. This polyether was treated with organometallic reagents such as Co complex or CuCl to give a cross‐linked polymer. This polymer synthesis is unusual in that it concurrently constructs both the polymer backbone and the functional side chains from three starting compounds. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5440–5448, 2005
A Large‐sample Confidence Band for a Multi‐response Ridge Path
Authors: Ding Rui , Lin Dennis K. J. , Peterson John J.
Published: September 2005

Ridge analysis in response surface methodology has received extensive discussion in the literature, while little is known for ridge analysis in the multi‐response case. In this paper, the ridge path is investigated for multi‐response surfaces and a large‐sample simultaneous confidence interval (confidence band) for the ridge path is developed. Copyright © 2005 John Wiley & Sons, Ltd.
Optimum Accelerated Life Testing Plans Based on Proportional Mean Residual Life
Authors: Zhao Wenbiao , Elsayed Elsayed A.
Published: September 2005

In this paper, we present an efficient and practical approach for designing accelerated life testing (ALT) plans based on the proportional mean residual life (PMRL) regression model. The plans determine the appropriate levels for each stress type and the number of test units allocated to each level in order to obtain accurate mean residual life estimates at normal operating conditions. Unlike previous ALT plans, the proposed plans need not assume the life–stress relationship. A numerical example that demonstrates the design of such accelerated plans is presented. The proposed plans can also be applied in situations with more than a single accelerating stress without any difficulties. Copyright © 2005 John Wiley & Sons, Ltd.
A Method for Correlating Field Life Degradation with Reliability Prediction for Electronic Modules
Authors: Coit David W. , Evans John L. , Vogt Nathan T. , Thompson James R.
Published: September 2005

A methodology was developed to correlate field life with observed degradation for electronics modules. This procedure was developed by identifying common deterioration characteristics in field units, modeling observed trends and then developing a model to predict future deterioration trends. This particular method focused on the deterioration of solder joint strength due to solder fatigue and comparing these values with a threshold based on known electrical failures. A conditional probability density function was formulated and quantified for both random shear strength and the minimum shear strength within a module. The conditional probability density function characterized both the changing mean and variance for a normally distributed random shear strength. With this methodology, time or mileage (life) prediction is based on the probability that the minimum performance response is less than a defined failure threshold. The methodology described herein promises to be an effective product development tool as the effect of design changes on product life can be more quickly and easily evaluated. While the technique developed herein is applicable to all electronic designs, the method was developed with a particular focus on understanding these relationships for automotive (harsh environment) applications. Copyright © 2005 John Wiley & Sons, Ltd.
Using Profile Monitoring Techniques for a Data‐rich Environment with Huge Sample Size
Authors: Wang Kaibo , Tsung Fugee
Published: September 2005

In‐process sensors with huge sample size are becoming popular in the modern manufacturing industry, due to the increasing complexity of processes and products and the availability of advanced sensing technology. Under such a data‐rich environment, a sample with huge size usually violates the assumption of homogeneity and degrades the detection performance of a conventional control chart. Instead of charting summary statistics such as the mean and standard deviation of observations that assume homogeneity within a sample, this paper proposes charting schemes based on the quantile–quantile (Q–Q) plot and profile monitoring techniques to improve the performance. Different monitoring schemes are studied based on various shift patterns in a huge sample and compared via simulation. Guidelines are provided for applying the proposed schemes to similar industrial applications in a data‐rich environment. Copyright © 2005 John Wiley & Sons, Ltd.
Studies of equilibrium geometries and electronic spectra for C78O4
Authors: Wu Shi , Teng Qiwen
Published: September 2005

Equilibrium geometries and relative stabilities of 24 possible isomers for C78O4 based on C78 (C2v) were studied by intermediate neglect of differential overlap (INDO) calculations. It was indicated that the most stable geometry is 28,29,30,31,52,53,73,78‐C78O4, where three oxygen atoms are added to the same hexagon, through which the longest axis of C78 (C2v) goes, and the forth oxygen atom is added to the C(73)C(78) bond intersected by the shortest axis of C78 (C2v), and epoxide structures are formed. Electronic spectra of C78O4 isomers were investigated based on the optimized geometries. The blue shift of the first absorption for 28,29,30,31,52,53,73,78‐C78O4 compared with that of C78 (C2v) was rationalized and nature of transition for the peaks discussed. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
HF and MP2 calculations on CN−, N2, AlF, SiO, PN, SC, ClB, and P2 using correlated molecular wave functions
Authors: Muniz E. P. , Jorge F. E.
Published: September 2005

Contracted basis sets of double zeta valence quality plus polarization functions (DZP) and augmented DZP basis sets, which were recently constructed for the first‐ and second‐row atoms, are applied to study the electronic ground states of the diatomic molecules CN−, N2, AlF, SiO, PN, SC, ClB, and P2. At the Hartree–Fock (HF) and/or Møller–Plesset second‐order (MP2) levels, total and molecular orbital energies, dissociation energies, bond lengths, harmonic vibrational frequencies, and dipole moments are calculated and compared with available experimental data and with the results obtained from correlation consistent polarized valence basis sets of Dunning's group. For N2, calculations of polarizabilities at the HF and MP2 levels with the sets presented above are also done and compared with results reported in the literature. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Probing the binding of ligands to estrogen receptor using an empirical system
Authors: Dottorini T. , Cozzini P.
Published: September 2005

The estrogen receptor (ER) is a ligand‐regulated transcription factor whose activity as an inducer or repressor of gene transcription depends on the nature of the ligand to which it is bound. The aim of this work is to evaluate the behavior of a set of compounds (antagonist molecules), using different docking experiments, in order to understand the relationship between ERα and such new ligands. With regard to the chemical properties of the ligands analyzed, we defined a specific guideline procedure designed for docking experiments. In our approach, we propose the use of the HINT scoring function in docking methodologies as a means of assessing the consistency of a docking solution, to discriminate correctly or near‐correctly docked orientations from incorrectly docked ones, thus compensating for the lack of experimental data. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Computation of the eigenvalues of the one‐dimensional Schrödinger equation by symplectic methods
Authors: Kalogiratou Z. , Monovasilis Th. , Simos T. E.
Published: September 2005

The computation of high‐state eigenvalues of the one‐dimensional time‐independent Schrödinger equation is considered by symplectic integrators. The Schrödinger equation is first transformed into a Hamiltonian canonical equation. Yoshida‐type symplectic integrators are used as well as symplectic integrators based on the Magnus expansion. Numerical results are obtained for a wide range of eigenstates of the one‐dimensional harmonic oscillator, the doubly anharmonic oscillator, and the Morse potential. The eigenvalues found by the symplectic methods are compared with the eigenvalues produced by Numerov‐type methods. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Quantification of antiretroviral drugs in dried blood spot samples by means of liquid chromatography/tandem mass spectrometry
Authors: Koal Therese , Burhenne Heike , Römling Regina , Svoboda Michal , Resch Klaus , Kaever Volkhard
Published: September 2005

For the first time approved antiretroviral drugs, i.e. protease inhibitors (PI) and non‐nucleoside reverse transcriptase inhibitors (NNRTI), were quantified in dried blood spots (DBS) from HIV/AIDS patient whole blood samples as the basis for therapeutic drug monitoring (TDM) by a robust simultaneous liquid chromatography/tandem mass spectrometry (LC/MS/MS) method. This study included seven PI (amprenavir, nelfinavir, indinavir, lopinavir, saquinavir, ritonavir, atazanavir) and two NNRTI (nevirapine, efavirenz). LC/MS/MS coupling was realized using a Phenomenex® Synergy Max RP LC column (150 × 2 mm, 4 µ) in combination with a tandem mass spectrometer (API 2000, Applied Biosystems/MDS Sciex Concord) operating in positive and negative multiple reaction monitoring (MRM) mode with reserpine as internal standard. DBS samples were punched out and extracted with 50:50 MeOH/0.2 M ZnSO4 (v/v) as extraction reagent. The method performance data for the drugs in DBS like limits of detection (LOD, 8–70 ng/mL), lower limits of quantification (LLOQ, 41–102 ng/mL), linearity (R2, 0.9981–0.9999), linear concentration ranges (41–10.000 ng/mL), accuracies (92–113%), recoveries (62–94%), and ion suppression were investigated and are comparable to data obtained from human plasma, which is the current standard matrix for TDM of PI and NNRTI. In this case, off‐line plasma sample preparation was performed by means of simple protein precipitation with 80:20 methanol/0.2 M ZnSO4 (v/v) as precipitation reagent. Significant correlations between real patient plasma and DBS were obtained for samples containing lopinavir, atazanavir, ritonavir, saquinavir, and efavirenz. DBS preparation as sampling alternative is well suited and practicable for TDM minimizing the high infection risk of HIV/AIDS samples and may facilitate sample mailing. Copyright © 2005 John Wiley & Sons, Ltd.
Simple modification of a protein database for mass spectral identification of N‐linked glycopeptides
Authors: Atwood James A. , Sahoo Satya S. , Alvarez‐Manilla Gerardo , Weatherly Daniel B. , Kolli Kumar , Orlando Ron , York William S.
Published: September 2005

We describe an algorithm which modifies a protein database such that during a database search deamidation is limited to asparagines strictly contained within the N‐glycosylation consensus sequence. The modified database was evaluated using a dataset created from the shotgun proteomic analysis of N‐linked glycopeptides from human blood serum. We demonstrate that the application of the modified database eliminates incorrect glycopeptide assignments, reduces the peptide false‐discovery rate, and eliminates the need for manual validation of glycopeptide identifications. Copyright © 2005 John Wiley & Sons, Ltd.
Gas chromatography/mass spectrometric analysis of methyl esters of N,N‐dialkylaminoethane‐2‐sulfonic acids for verification of the Chemical Weapons Convention
Authors: Pardasani Deepak , Gupta Arvinda K. , Palit Meehir , Shakya Purushottam , Kanaujia Pankaj K. , Sekhar K. , Dubey Devendra K.
Published: September 2005

This paper describes the synthesis and gas chromatography/electron ionization mass spectrometric (GC/EI‐MS) analysis of methyl esters of N,N‐dialkylaminoethane‐2‐sulfonic acids (DAESAs). These sulfonic acids are important environmental signatures of nerve agent VX and its toxic analogues, hence GC/EI‐MS analysis of their methyl esters is of paramount importance for verification of the Chemical Weapons Convention. DAESAs were prepared by condensation of 2‐bromoethane sulfonic acid with dialkylamines, and by condensation of dialkylaminoethyl chloride with sodium bisulfite. GC/EI‐MS analysis of methyl esters of DAESAs yielded mass spectra; based on these spectra, generalized fragmentation routes are proposed that rationalize most of the characteristic ions. Copyright © 2005 John Wiley & Sons, Ltd.
Determination of rapamycin: quantification of the sodiated species by an ion trap mass spectrometer as an alternative to the ammoniated complex analysis by triple quadrupole
Authors: Pieri Maria , Miraglia Nadia , Castiglia Loredana , Genovese Giuliana , Basilicata Pascale , Simonelli Angela , Acampora Antonio
Published: September 2005

Rapamycin is a potent immunosuppressive drug capable of significantly reducing acute graft rejection in kidney, liver and heart transplant patients. Its immunosuppressive activity and adverse effects have been related to rapamycin concentration, and therapeutic drug monitoring of the drug is deemed appropriate. This work was aimed at developing a new quantification method based on the isolation of the [M+Na]+ ion as precursor and its further fragmentation through an ion trap mass spectrometer equipped with an electrospray ionization source. A limit of detection (LOD) of 0.7 ng/mL was obtained, while the lower limit of quantification (LLOQ) was 2.4 ng/mL. The accuracy and reproducibility of the responses were evaluated and compared with results obtained when the [M+NH4]+ ion was chosen as the precursor in a triple quadrupole mass spectrometer. In this case the LOD was 0.5 ng/mL and the LLOQ 1.7 ng/mL. Data showed that it would be possible to use the quantification of the sodiated species for the routine determination of rapamycin, as an alternative to the commonly adopted method based on the ammoniated complex. Copyright © 2005 John Wiley & Sons, Ltd.
Chiral supercritical fluid chromatography/tandem mass spectrometry for the simultaneous determination of pindolol and propranolol in metabolic stability samples
Authors: Hsieh Yunsheng , Favreau Leonard , Cheng K.‐C. , Chen Jiwen
Published: September 2005

A chiral packed‐column supercritical fluid chromatographic (pSFC) system coupled to tandem mass spectrometer (MS/MS) for the rapid measurements of (R,S)‐propranolol and (±)‐pindolol in metabolic stability samples was developed. The effects of the eluent flow rates and compositions, as well as of the nebulizer temperature, on the chromatographic performance and the ionization efficiency of the analytes in positive ion mode under pSFC conditions were studied. The ionization mechanism of the analytes in the CO2/methanol atmospheric pressure chemical ionization (APCI) environments with or without the use of an additive was studied. The chiral pSFC‐APCI‐MS/MS approach requiring approximately 2 min per sample was applied for the simultaneous determination of two pairs of racemic drugs in in vitro samples at low nanogram per milliliter concentrations. Copyright © 2005 John Wiley & Sons, Ltd.
Simultaneous determination of nicotinic acid and its metabolites using hydrophilic interaction chromatography with tandem mass spectrometry
Authors: Hsieh Yunsheng , Chen Jiwen
Published: September 2005

A hydrophilic interaction chromatographic (HILIC) system interfaced with atmospheric pressure ionization (API) sources and a tandem mass spectrometer (MS/MS) was developed for the simultaneous determination of nicotinic acid (NiAc) and its metabolites in dog plasma in support of a pharmacokinetic study. A silica column was adapted for separation of NiAc and its two metabolites, nicotinamide (NiNH2) and nicotinuric acid (NiUAc), under HILIC conditions. The influence of experimental factors such as the composition of mobile phase on ionization efficiency and chromatographic performance of all analytes was investigated. The feasibility of the proposed HILIC/MS/MS methods was explored by comparing the plasma levels of NiAc, NiNH2, and NiUAc in dog obtained by using either electrospray ionization or atmospheric pressure chemical ionization interfaces in positive ion mode. The methods were partially validated in terms of inter‐day accuracy and precision, extraction recovery, benchtop and freeze/thaw stability. Further, the potential of ionization suppression resulting from endogenous components of the biological matrixes on the HILIC/API‐MS/MS methods were investigated using the post‐column infusion technique. Copyright © 2005 John Wiley & Sons, Ltd.
The random binary growth model
Authors: Georgiou Nicholas
Published: October 2005

We describe a family of models of random partial orders, called classical sequential growth models, and study a specific case, which is the simplest interesting model, called a random binary growth model. This model produces a random poset, called a random binary order, B2, on the vertex set ℕ by considering each vertex n ≥ 2 in turn and placing it above 2 vertices chosen uniformly at random from the set {0,…,n − 1} (with additional relations added to ensure transitivity). We show that B2 has infinite dimension, almost surely. Using the differential equation method of Wormald, we can closely approximate the size of the up‐set of an arbitrary vertex. We give an upper bound on the largest vertex incomparable with vertex n, which is polynomial in n, and, using this bound, we provide an example of a poset P, such that there is a positive probability that B2 does not contain P. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2005
Radical reformism: towards critical ecological modernization
Authors: Orsato Renato J. , Clegg Stewart R.
Published: September 2005

According to a specialized research area within environmental sociology – ecological modernization theory – the shift towards seeking to protect the environment constitutes a broadly emergent sociological phenomenon: the radicalization of modernity. The understanding of the fundamentals of such phenomenon is, therefore, crucial for both the practice and theorization of organization and environment. This is the main reason why this paper seeks to incorporate ideas from the disciplines of both environmental sociology and organization theory. By delving into the main sources of dynamism that ‘produced’ modernity the paper argues that a sustainable organizational practice depends on the incorporation of a special type of radicalism into ecological modernization. The paper anchors its main arguments in research conducted in the European automobile industry – a socio‐technical context undergoing ecological modernization. The main conclusions of the paper relate to the nature of the reforms required for organizational practices to facilitate sustainable industrial development. Copyright © 2005 John Wiley & Sons, Ltd and ERP Environment.
Signaling molecularly imprinted polymers: molecular recognition‐based sensing materials
Authors: Takeuchi Toshifumi , Mukawa Takashi , Shinmori Hideyuki
Published: October 2005

Molecular imprinting is a template polymerization technique that can easily provide synthetic polymers capable of molecular recognition for given target molecules. In addition to their highly specific recognition ability, we are attempting to introduce signaling functions to molecularly imprinted polymers, enabling them to respond according to specific binding events. Some of our work regarding such signaling molecularly imprinted polymers is presented here, including molecularly imprinted polymers that induce spectral shifts of target compounds because of binding. Such compounds include hydrogen‐bonding‐based fluorescent imprinted polymers and metalloporphyrin‐based signaling molecularly imprinted polymers. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 5: 263–275; 2005: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20052
Electronically‐coupled MM quadruply‐bonded complexes of molybdenum and tungsten†
Authors: Chisholm Malcolm H. , Patmore Nathan J.
Published: October 2005

The reaction of M2(O2CBut)4 (M = Mo, W) with a dicarboxylic acid in toluene yields compounds of general formula [M2]‐O2C‐X‐CO2‐[M2] ([M2] = M2(O2CBut)3; X = conjugated spacer). The M2 units are electronically coupled via interactions between the M2 δ and dicarboxylate π* orbitals, and the magnitude of this coupling is revealed by electronic structure calculations and spectroscopic data. These compounds show intense metal to ligand charge transfer (MLCT) absorptions in the visible region of the electronic spectrum that are temperature and solvent dependent. Evidence of electronic coupling is seen in their cyclic voltammograms, which show two successive one‐electron oxidations. The extent of electronic coupling in the mixed valence radical cations [M2]‐O2C‐X‐CO2‐[M2]+, generated by oxidation with one equivalent of AgPF6 or FeCp2PF6, is evaluated by EPR and UV–vis–NIR spectroscopic data, and delocalized behavior is observed in compounds with W2 units separated by up to 13.6 Å. The simplicity of the frontier M2 orbital interactions with the bridge π orbitals provides a convenient system with which to study electron transfer in mixed valence systems, as compared to the extensively studied, but more complicated, dinuclear t2g6/t2g5 mixed valence compounds. Oligomeric and polymeric compounds incorporating M2 units have also been synthesized, having general formula [M2(O2CR)2(O2C‐Thio‐CO2)]n (Thio = n‐hexyl substituted ter‐ and quinque‐thiophenes). They can be deposited as thin films by spin coating, and show photoluminescence and electroluminescence. These metallo‐polythiophenes show potential for application in electronic materials. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 5: 308–320; 2005: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20053
Detection efficiency of energy‐dispersive detectors with low‐energy windows
Authors: Scholze F. , Procop M.
Published: September 2005

Energy dispersive X‐ray spectrometry offers the opportunity for fast composition determination of specimens by X‐ray fluorescence or electron probe microanalysis. For fundamental parameter based quantification, the knowledge of the detection efficiency of the spectrometer is essential. At low energies the efficiency is strongly influenced by X‐ray absorption in the radiation entrance window. State‐of‐the‐art windows consist of polymer foil containing C, N, and O, coated with Al and in some cases with a special B compound. The foil is supported by a Si grid to withstand the atmosphere pressure. The absorption of all these components must be known to describe the detection efficiency.

The transmittance of three types of widely used commercial windows has been measured. Transmittance curves have been fitted by analytical expressions using tabulated mass absorption coefficients. Because tabulated mass absorption coefficients do not consider near edge effects, there are strong deviations between measured and calculated transmittance below 0.6 keV. It is proposed to model the spectrometer efficiency by the measured window transmittance and calculated absorptions from front contact and possible contaminations. This reduces the number of unknown parameters drastically. Copyright © 2005 John Wiley & Sons, Ltd.
X‐ray and electron microprobe investigation of the speleothems from Godarville tunnel
Authors: Kuczumow Andrzej , Genty Dominique , Chevallier Pierre , Nowak Jakub , Florek Marek , Buczyńska Anna
Published: September 2005

A calcite deposit (stalagmite) from the Godarville tunnel (Belgium) was investigated by the use of x‐ray and electron microprobes in order to detect any seasonal variations present in the chemical data and to make a comparison with meteorological data. The uniqueness of this speleothem system is that it is human constructed, controlled from the chronological point of view and with complete temperature and hydrological documentation. The Godarville tunnel stalagmites started to form since the time of closing down of the tunnel in 1960 and continued until the collection of the samples in December 1992. The growth of the annual laminae was observed on the cross‐sections of several stalagmites and attributed to consecutive years and even seasons. The laminar structure, ascribed to seasonal variations, is very clear and formed by a set of alternating bright, porous and dark, compact calcite layers. This structure gave rise to the optical profiles of the annual variability that were compared with the x‐ray synchrotron‐based microprobe chemical profile data obtained at LURE (Orsay University, France). Using this method, several profiles were measured: Ca as the main element, Sr as a very important minor component and Fe, Zn, Pb and Br as trace elements. The results display an impressive correlation between the spatial distributions of Sr and Br with the optical linear profile of the sample, demonstrating that these elements also have a seasonal variation in the stalagmite layers. The Fe, Zn and Pb concentration profiles were characterized by sudden and random increases in contents (up to 20 times over background levels) whose origin is still uncertain. The results were supplemented by similar linear scan measurements made by the electron microprobe. The results show that Sr concentrates in the bright layers whereas the Mg spatial distribution is less correlated with the optical linear scan. A strontium‐rich layer is formed during the autumn/winter periods. It is consistent with the ways of inclusion of that element in calcite, with the temperature‐dependent and hydrological aspects. Copyright © 2005 John Wiley & Sons, Ltd.