bluuebunny/crossref_metadata_2025 huggingface dataset:
Medial knee joint loading increases in those who respond to hyaluronan injection for medial knee osteoarthritis
Authors: Briem Kristin , Axe Michael J. , Snyder‐Mackler Lynn
Published: April 2009

Knee osteoarthritis (OA) is a cause of decline in function and the medial compartment is often affected. Intraarticular injection of hyaluronic acid (HA) is indicated as a symptom modifying treatment with at least 6 months passing between consecutive injection series. The effects of HA injection on gait variables have not been extensively examined. Therefore, our objective was to investigate the effects of HA injection on gait in people with medial knee OA. Twenty‐seven subjects were included; each was tested prior to treatment (baseline), no later than 3 weeks following the last injection (post‐HA), and again 5 months after treatment ended (follow‐up). Responder criteria were defined to identify responders and non‐responders. Subjects underwent 3D gait analysis, muscle activity was sampled, and co‐contraction indices were calculated. Responders experienced increased peak knee adduction moments post‐HA, whereas non‐responders did not. Improved self‐report scores were associated with increased knee adduction moments and increased medial co‐contraction. Pain relief may result in higher loading onto the already vulnerable medial compartment due to changes in lower limb mechanics and muscle activation patterns. Eventually this may result in a more rapid progression of joint deterioration. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1420–1425, 2009
Impact of volatile compounds generated by essential oils on Aspergillus section Flavi growth parameters and aflatoxin accumulation
Authors: Bluma Romina , Landa Maria F , Etcheverry Miriam
Published: April 2009

BACKGROUND: The advantage of essential oils is their bioactivity in the vapour phase, a characteristic that makes them attractive as possible fumigants for stored grain protection. In this study the antifungal and antiaflatoxigenic effects of the volatile fractions of five essential oils (EOs) were evaluated by vapour contact on Aspergillus section Flavi isolates.

RESULTS: In maize meal extract agar the volatile fractions of Pimpinella anisum L. (anise), Pëumus boldus Mol. (boldus), Hedeoma multiflora Benth. (mountain thyme), Lippia turbinata var. integrifolia (Griseb.) (poleo) and Syzygium aromaticum L. (clove) were able to decrease the growth rate and lag phase of aflatoxigenic isolates. Boldus EO showed the best antifungal effect on Aspergillus section Flavi growth rate. In sterilised maize grains, boldus and poleo EOs showed antifungal effects on growth rate and aflatoxin accumulation. The volatile fraction of boldus EO completely inhibited the growth of isolates at water activity (aw) levels of 0.955, 0.930 and 0.900, while poleo EO showed this effect only at the lower aw levels (0.930 and 0.900). All aflatoxigenic isolates showed reduced total aflatoxin accumulation in the presence of boldus EO under all aw conditions.

CONCLUSION: These findings clearly indicate that the volatile fraction of boldus EO could be used to control aflatoxigenic fungi in stored maize. Copyright © 2009 Society of Chemical Industry
Feasibility of using digital speckle correlation in the study of seal contacts
Authors: Gren Per , Kassfeldt Elisabet
Published: April 2009

This paper presents studies of the contact between a soft rubber specimen and glass counterface using the Digital Speckle Correlation method, which provides information of displacements and structural similarities between recorded images. The setup is designed with a real contact and changes in the contact can be varied. Microscopic images using laser light illumination for different displacements are recorded and correlated. The results show that the contact area can be identified both for dry and lubricated contacts. The method can be applied on different geometries, surface roughness and lubricants. Influences of scars and contaminations, e.g. wear particles, may also be analysed. Copyright © 2009 John Wiley & Sons, Ltd.
Initial exploration of tribological performance of novel triazine derivatives in water
Authors: Sheng Liping , Li Fenfang , Fan Chengkai
Published: April 2009

Two novel ashless and non‐phosphorus triazine derivatives, 2,4,6‐tri‐[N‐hydroxyethyl‐amino‐methylenesulfanyl]‐s‐triazine and 2,4,6‐tri‐[N,N‐bishydroxyethyl‐amino‐methylenesulfanyl]‐s‐triazine, were synthesised and their structures were analysed through elemental analysis. Their tribological behaviours in water were evaluated with a four‐ball machine, and the results indicate that their wear resistance and load‐carrying properties were excellent. The chemical features of the worn steel surface were observed and examined by means of inverted metallurgical microscopy and energy dispersive X‐ray spectroscopy. The analytical results of typical elements on the worn steel surface demonstrated, during the lubricating process, that the additives reacted with counter‐face metal and generated a boundary lubricating and protecting film containing elements of S, N and others, which contributes to improve the tribological properties of the test fluid. Copyright © 2009 John Wiley & Sons, Ltd.
Structural elucidation and NMR spectral assignment of three new furostanol saponins from the roots of Tupistra chinensis
Authors: Guo Zhiyong , Zou Kun , Wang Junzhi , Liu Chuang , Tang Zichun , Yang Chunyan
Published: April 2009

Three new furostanol saponins (1–3) were isolated from the roots of Tupistra chinensis (T. chinensis). And their structures were elucidated on the basis of NMR and mass spectrometry (MS) spectral analysis. Copyright © 2009 John Wiley & Sons, Ltd.
Optimal control problem for nonstationary Schrödinger equation
Authors: Yildiz Bunyamin , Kilicoglu Oguz , Yagubov G.
Published: April 2009

In this study we investigate an optimal control problem for the nonstationary Schrödinger equation; the questions needed to correctly identify the optimal control problem were answered, and the existence and uniqueness of the solution and the necessary and sufficient conditions for the solution were investigated. We consider the initial situation as control for the controlled system. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
Numerical solution of nonlinear Schrödinger equation by using time‐space pseudo‐spectral method
Authors: Dehghan Mehdi , Taleei Ameneh
Published: April 2009

In this article, a time‐space pseudo‐spectral method is proposed for the numerical solution of nonlinear Schrödinger equation. The employed method is based on Chebyshev‐Gauss‐Lobbato quadrature points. Using the pseudo‐spectral differentiation matrices the problem is reduced to a system of nonlinear algebraic equations. However, this method is basically a spectral method, but a subdomain‐in‐time algorithm is used which yields a smaller nonlinear system to study long‐time numerical behavior. Because the time‐space pseudo‐spectral method has spectral accuracy, we present numerical experiments which show high accuracy of this method for the variant nonlinear Schrödinger equations and also particular attention is paid to the conserved quantities as an indicator of the accuracy. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2010
The role of the museum shop in extending the visitor experience
Authors: Kent Tony
Published: April 2009

The aim of the research is to assess the role of the museum shop in extending the learning experience in the museum. The research is situated in the theoretical framework of museum experiences and learning. It acknowledges environmental influences on learning, and of consumption sites that synthesise leisure and consumption and create memorable sensory experiences that engage customers.

The exploratory approach uses mixed methods to examine visitors' knowledge and experience of museums and their shops. The first phase of the research was undertaken with in‐depth interviews to scope the experience of museum shops and their contribution to learning. The second phase was undertaken with visitors to the Imperial War Museum (IMW) in London through a convenience sample which elicited 150 responses to a semi‐structured questionnaire. The research demonstrates the significance of the museum shop as a destination for museum visitors, and its role in creating experiences that can supplement the museum's educational priorities and a return to the everyday world of familiar objects.

Copyright © 2009 John Wiley & Sons, Ltd.
Personality, threat identification and emotional processing
Authors: Leikas Sointu , Lindeman Marjaana
Published: April 2009

Individual differences in threat identification moderate the associations of personality with emotional experience and behaviour. The present two studies examined whether adeptness at threat identification also moderates the associations between personality and emotional processing. Participants completed personality scales, different emotional processing measures and a threat versus non‐threat categorization task. Adeptness at threat identification moderated the relations between agreeableness and negative interpretation of ambiguous stimuli, negative reactivity and positive likelihood judgments, and the relation between neuroticism and negative recall. The results supported the view that agreeableness and adeptness at threat identification together form a self‐regulation system. The results may have important implications for trait and health psychology. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis and characterization of new optically active polymers carrying calix[4]arene and amino acid units in the main chain and their binding properties towards toxic heavy metals
Authors: Hajipour Abdol‐Reza , Habibi Sakineh , Ruoho Arnold E
Published: April 2009

BACKGROUND: A series of novel optically active polymers containing upper rim calix[4]arene was prepared from the polycondensation reaction of calix diamine derivative 2 with two optically active diacid chlorides.

RESULTS: The optically active compounds were prepared from the reaction of a pyromellitic dianhydride with two chiral amino acids. The optically active polymers were obtained in a yield of 80–86% and had an inherent viscosity of 0.20–0.26 dL g−1. The polymers were characterized using Fourier transform infrared and 1H NMR spectroscopy and elemental analysis. Studies of the complexation of the polymers towards some alkali metal and toxic transition metal cations were performed using solid–liquid sorption procedures and comparisons made with the starting monomer.

CONCLUSION: It is evident from the complexation studies that the polymers investigated are good polymeric ionophores for alkali metal cations like Na+ and K+, for Ag+ and for toxic heavy metal cations such as Cu2+, Co2+, Cd2+ and Hg2+. These polymers are good candidates for use in chiral stationary phases for separation of enantiomers in ionic media, as well for removing metal ions. Copyright © 2009 Society of Chemical Industry
Photo‐crosslinking of poly[ethene‐stat‐(methacrylic acid)] functionalised with maleimide side groups
Authors: Schmeling Nadine , Hunger Katharina , Engler Gernot , Breiten Benjamin , Rölling Patrick , Mixa Alexander , Staudt Claudia , Kleinermanns Karl
Published: April 2009

BACKGROUND: Photo‐crosslinkable polymers are well known and commercially applied as photoresists. But so far they have not been applied as membrane materials for separation processes. They would offer certain advantages in membrane fabrication over conventional crosslinked polymer materials. Therefore, in this work, a poly[ethene‐stat‐(methacrylic acid)] (PEMAA) which is a potential membrane polymer for different separation problems was functionalised with photo‐crosslinkable maleimide side groups.

RESULTS: It has been shown that PEMAA can be used as basic polymer material and a conversion with 3‐hydroxypropylmaleimide is possible in order to obtain a photo‐crosslinkable polymer. Investigation of the crosslinking mechanism was performed using stationary infrared and UV‐visible spectroscopy as well as nanosecond transient spectroscopy absorption measurements of a rotating film. Intense transient absorption of the maleimide‐esterified PEMAA occurs at 250 nm in the film pointing to maleimide anion formation and crosslinking via an ionic dimerisation mechanism.

CONCLUSION: It is found that crosslinking reactions can be observed spectroscopically in situ using a maleimide‐functionalised PEMAA. Furthermore, experiments can be performed in the liquid phase (polymer in solution) as well as in the solid phase (polymer film) using a rotating polymer film sample. Maleimide anion formation and crosslinking via an ionic dimerisation mechanism can be investigated by variation of the polymer structure as well as the structure of the maleimide side groups. Copyright © 2009 Society of Chemical Industry
Polydimethylsiloxane/silica composites incorporating pyrite powders for actuation elements
Authors: Cazacu Maria , Ignat Mircea , Racles Carmen , Vlad Angelica , Alexandru Mihaela , Zarnescu George
Published: April 2009

BACKGROUND: Among polymers, elastomers can achieve very large deformations and deliver relatively high forces when an electric field is applied to them. In addition, a number of active components, such as carbon black, multi‐walled nanotubes or metallic powders, can be used to obtain increased effects. One elastomer used as a host for these active fillers is polydimethylsiloxane.

RESULTS: Pyrite powders were physically incorporated in a polymeric matrix consisting of interconnected polydimethylsiloxane/silica networks. The mixtures were processed as films by casting on a Teflon substrate before crosslinking. The films thus formed were investigated from the point of view of their mechanical behaviour and were tested as active elements in an actuation system.

CONCLUSION: Electromechanical tests of the polymeric membranes under investigation revealed a very good behaviour for applications in nano‐ and micro‐actuation. Some of the prepared films showed significant displacements at reasonable voltages (i.e. 56 000 nm at 460 V or 1000 nm at 6 V). Sensitivities between 2.608 and 333.33 nm V−1 were obtained in inverse dependence on the Young's modulus values. Copyright © 2009 Society of Chemical Industry
The Rational Choice of Not Applying Project Risk Management in Information Technology Projects
Authors: Kutsch Elmar , Hall Mark
Published: April 2009

The management of risk is considered a key discipline by the Project Management Institute and the Association for Project Management. However, knowledge of what needs to be done frequently fails to result in action consistent with that knowledge. The reasons for this seem to have received little attention. This study researched the degree of use of project risk management and barriers that prevent IT project managers from using risk management. Interviews and a survey were carried out. The results show that, in one-third of cases, because of the problem of cost justification, no formal project risk management process was applied.
The effect of β‐methylation on the conformation of α, β‐dehydrophenylalanine: a DFT study
Authors: Broda Małgorzata A. , Buczek Aneta , Siodłak Dawid , Rzeszotarska Barbara
Published: April 2009

Dehydroamino acids are non‐coded amino acids that offer unique conformational properties. Dehydrophenylalanine (ΔPhe) is most commonly used to modify bioactive peptides to constrain the topography of the phenyl ring in the side chain, which commonly serves as a pharmacophore. The Ramachandran maps (in the gas phase and in CHCl3 mimicking environments) of ΔPhe analogues with methyl groups at the β position of the side chain as well as at the C‐terminal amide were calculated using the B3LYP/6‐31 + G** method. Unexpectedly, β‐methylation alone results in an increase of conformational freedom of the affected ΔPhe residue. However, further modification by introducing an additional methyl group at C‐terminal methyl amide results in a steric crowding that fixes the torsion angle ψ of all conformers to the value 123°, regardless of the Z or E position of the phenyl ring. The number of conformers is reduced and the accessible conformational space of the residues is very limited. In particular, (Z)‐Δ(βMe)Phe with the tertiary C‐terminal amide can be classified as the amino acid derivative that has a single conformational state as it seems to adopt only the β conformation. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
Regioselective and sequential reactivity of activated 2,5‐diketopiperazines
Authors: Farran Daniel , Echalier Delphine , Martinez Jean , Dewynter Georges
Published: April 2009

The electrophilic reactivity of Boc‐DKPs has been studied. Thanks to Boc activation, the opening ability of carbonyl lactam groups is enhanced. According to experimental conditions, this enabled the synthesis of Boc‐amino acid derivatives or original dipeptides via a regioselective and sequential way. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
Spanning the Hilbert space with an even tempered Gaussian basis set
Authors: Cherkes Ira , Klaiman Shachar , Moiseyev Nimrod
Published: April 2009

In this work we show how and why the well‐known Gaussian even‐tempered basis spans the Hilbert space evenly. This basis is thought to be chosen based mainly on empirical results. However as shown here it can also be deduced based on rigorous numerical ground using a Gram‐Schmidt orthogonalization procedure. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Efficient calculation of the exchange in the Fourier representation of HF‐LCAO‐CO equations for 1D periodic systems
Authors: Fripiat Joseph G. , Delhalle Joseph
Published: April 2009

Recent advances in the preparation of quasi‐1D nano‐objects motivate further the development of suitable theoretical models for the calculation of their properties (structural, electronic, etc.). Hartree–Fock crystal orbital‐based methodologies and beyond, in spite of their cost, provide a consistent basis for calculations on systems exhibiting periodicity in one direction. One of the often reported drawbacks is the difficulty to deal with the long‐range contributions (Coulomb and exchange). In this contribution, it shown that the Fourier representation of the HF‐LCAO‐CO equations is an appropriate framework to effectively compute the exchange contributions in GTO basis sets. A numerical example illustrates the efficiency of the proposed procedure. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
An analytical representation of shell corrections for stopping power
Authors: Sabin John R. , Oddershede Jens
Published: April 2009

We propose an ansatz for an analytical representation of shell corrections to the stopping power that is amenable to mathematical manipulation when considering stopping power properties. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
The leaky aquifer function revisited
Authors: Temme Nico M.
Published: April 2009

This article discusses the leaky aquifer function considered in a recent article by Frank Harris in the Journal of Computational and Applied Mathematics (2008). We describe the properties of an integral representing this function and give details on how to compute this function with a single algorithm for a wide range of the parameters. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Intermediate Hamiltonian Hilbert space coupled cluster method: Theory and pilot application
Authors: Eliav Ephraim , Borschevsky Anastasia , Shamasundar K. R. , Pal Sourav , Kaldor Uzi
Published: April 2009

The intermediate Hamiltonian state universal (Hilbert‐space) coupled‐cluster method is presented, using a formalism similar to that developed for the valence universal (Fock‐space) approach. The method is expected to be applicable to many states not accessible by traditional multiroot multireference all‐order size‐extensive approaches. A pilot application to excited states of atomic beryllium shows good convergence and agreement with experiment and full CI values. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Numerical orbital Fourier space approach to polymer band‐structure calculations
Authors: Talman J. D. , Delhalle J. , Fripiat J. G.
Published: April 2009

The periodic symmetry of polymer chains can be applied via Bloch functions to polymer band structure calculations (Delhalle and Harris, Phys Rev B 1985, 31, 6755). The possibility of replacing Gaussian orbitals with numerically defined orbitals in this approach is discussed. Two modifications of the theory to overcome problems with the cancellation of divergent terms are described. Result for a LiH chain are compared with analytic Gaussian orbital results. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
An ab initio analysis of charge redistribution upon isomerization of retinal in rhodopsin and bacteriorhodopsin
Authors: Corn Brittany , Malinovskaya Svetlana A.
Published: April 2009

In the framework of quantum‐chemical methods (RHF, MP2, and DFT), we study the reaction of photoinduced isomerization of biological molecules—retinal in rhodopsin (Rh) and bacteriorhodopsin (BRh)—the key intermediates in the vision process. The charge redistribution in the retinal chromophore of these biological molecules as the mechanism of the photoinduced isomerization is investigated. The results of the Mulliken, Löwdin, Natural Bond, and ESP population analyses are compared and validated. We demonstrate that the isomerization reaction is accompanied by the substantial charge relocation within the isomerization region with the electron localization on C11 for the retinal in Rh and C14 for the retinal in BRh. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Separable representations of the Coulomb interaction
Authors: Linderberg Jan
Published: April 2009

Error limits are developed for some separable approximations to the representation of the Coulomb interaction matrix elements. They are directed towards the application of Slater atomic orbital basis sets in large‐scale molecular calculations. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Exact mathematical treatment of the modifications of finite‐dimensional quantum systems
Authors: Živković Tomislav P.
Published: April 2009

Low rank modification (LRM) is a new mathematical formalism by which one can express eigenvalues and eigenstates of the modified system B in terms of the eigenvalues and eigenstates of the original system A. In this respect, LRM is similar to a standard perturbation expansion, which also expresses eigenvalues and eigenstates of the perturbed system B in terms of the eigenvalues and eigenstates of the unperturbed system A. However, unlike perturbation expansion, LRM produces correct results however strong the “perturbation” of the original system A. LRM is here applied to finite n‐dimensional systems A and B that are described by generalized n × n eigenvalue equations. In the LRM approach, modified system B is described by a ρ × ρ matrix equation, where ρ is the dimension of the space affected by the “modification” of the original system A. In mathematical terms, ρ is the rank of the operators that describe this modification. In many important cases, ρ << n, which results in the substantial numerical efficiency of the LRM approach. The method is illustrated with two examples. In the first example, LRM is applied to the vibrational isotope effect within the harmonic approximation. In particular, out‐of‐plane vibrations of benzene (H,D)‐isotopomers are analyzed in this way. In the second example, LRM is applied to some problems in a solid state physics. LRM provides a new mathematical treatment of all those features that break translational symmetry of a solid, such as point defects, the surface of a solid, etc. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Effects of local Coulomb potentials on acid and base protonation–deprotonation rates and equilibria
Authors: Smuczyńska Sylwia , Simons Jack
Published: April 2009

Ab initio electronic structure methods, even when performed at a very modest level, applied to the energy profiles for deprotonation of an organic acid or of a protonated amine in the presence of proximal charged groups yield data that suggest the following: 1. The proton affinity of an amine tethered to a surface can be altered substantially by the presence of proximal positively charged groups. 2. Barriers (above the thermodynamic energy requirement) along the amine protonation–deprotonation pathway arise when positive charges are tethered nearby. 3. A competition between the attractive intrinsic NH bonding potential and the repulsive Coulomb potential between the departing proton and the proximal positive charges is the primary source of the above two results. 4. There is much less change in the equilibrium constant K or the deprotonation and protonation rate constants k1 and k−1 for an organic acid tethered to a surface when in the presence of proximal negative charges. 5. The attractive intrinsic OH bonding potential and the attractive Coulomb potential between the proton and the proximal and nascent negative charges act in concert in the organic acid case. So, unlike the amine example, there is no competition between the dominant potentials and, as a result, no pronounced barriers occur along the reaction path. The relevance of these findings to acid–base properties of surfaces and nanoparticles are discussed. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Application of the method of increments to the adsorption of H2S on graphene
Authors: Paulus Beate , Rosciszewski Krzysztof
Published: April 2009

The method of increments is applied to the adsorption energy of H2S on a graphene layer using a CCSD(T) correlation treatment. We determine the incremental expansion for the correlation contribution to the adsorption energy in terms of localized orbitals of the molecule and the surface. The changes in the correlation energy of the molecule and the individual localized surface orbitals are repulsive and small, the major contributions arise from the joint correlation of molecule and surface orbitals. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
A numerical study of the asymptotic convergence characteristics of partial averaged and reweighted Fourier path integral methods
Authors: Kunikeev Sharif , Freeman David L. , Doll J. D.
Published: April 2009

The asymptotic convergence characteristics with respect to the number of included path variables of the partial average and reweighted Fourier path integral methods are numerically compared using a Gaussian fit to the one‐dimensional Lennard‐Jones potential. Using harmonic inversion to determine the parameters of the Gaussian fit potential appropriate for neon, the energy eigenvalues and thermodynamic properties of the Gaussian fit and the Lennard‐Jones interaction agree to better than 1%. Using Monte Carlo methods to study the Gaussian fit potential, the systematic error associated with the truncation of the number of path variables is found to be larger for the reweighted method than the partial average method for the same number of path variables actually used. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Spheroidal confinement of a single electron and of the hydrogen atom, the H and HeH++ molecular ions with arbitrary nuclear positions along the major axis
Authors: Cruz Salvador A. , Colín‐Rodríguez Ricardo
Published: April 2009

Evidence is given on the usefulness of the variational method to explore the nonseparable Schroedinger problem for the energy evolution of one‐electron atoms and diatomic molecular ions confined by a hard prolate spheroidal cavity when the nuclear positions do not coincide with the foci. In this work, we study explicity the case of the hydrogen atom (H) and the H and HeH++ under the aforementioned confinement conditions and obtain variationally the energy evolution as a function of nuclear positions along the major axis of a confining spheroid of fixed size and eccentricity. The particular case of an electron (e−) under the same confinement conditions is also addressed using the same methodology. Our calculations are restricted to the ground states of H (1sσ), HeH++ (1sσ), e−(1sσ) and the ground‐state (1sσg) and first excited state (2pσu) of H. It is shown that a simple LCAO Dickinson‐type variational ansatz wavefunction adapted for the confinement case of all systems treated in this work provides very rewarding results for the energy dependence on the size and shape of the confining cavity when compared with corresponding available exact calculations. For e− as well as for H, H and HeH++ with “on‐focus” nuclear positions excellent general quantitative agreement is observed. For the “off‐focus” case, moderate quantitative agreement is obtained with available accurate B‐spline variational calculations for H. For the molecular systems with “off‐focus” nuclear positions, the results of this work are the first of this kind. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Few sketches on connections between the Riccati and Ermakov–Milne–Pinney equations
Authors: Kryachko Eugene S.
Published: April 2009

In this work, we focus on some connections that exist between the Riccati and Ermakov–Milne–Pinney equations, particularly those which are established via the Schrödinger equation. Some formulas that express the general solution of the Riccati and Schrödinger equations in terms of a particular solution of the Riccati equation are obtained. It is shown that the difference between the general and particular solutions of the normal Riccati equation satisfies the Ermakov–Milne–Pinney equation with λ = −1/4. The formulas derived in this work are discussed in view of their quantum chemical applications, especially related to the WKB approach that is applied to describe the semiclassical behavior of molecules. This discussion is illustrated by a simple model of quantum harmonic oscillator. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Structural characterization and identification of C19‐ and C20‐diterpenoid alkaloids in roots of Aconitum carmichaeli by rapid‐resolution liquid chromatography coupled with time‐of‐flight mass spectrometry
Authors: Hu Rong , Zhao Jing , Qi Lian‐Wen , Li Ping , Jing Shan‐Lin , Li Hui‐Jun
Published: April 2009

Aconite alkaloids from the roots of Aconitum carmichaeli (Fuzi, in Chinese) have been investigated by rapid‐resolution liquid chromatography coupled with time‐of‐flight mass spectrometry (TOFMS) in positive mode. With dynamic adjustment of the key role as fragmentor voltage in TOFMS, an efficient transmission of the ions was achieved to obtain the best sensitivity for providing the molecular formula for each analyte, and abundant fragment ions for structural information. Fifteen authentic standards isolated from Fuzi with various structures were first characterized by TOFMS, including diester‐diterpenoid alkaloids (DDAs), monoester‐diterpenoid alkaloids (MDAs), alkylol amine‐diterpenoid alkaloids (ADAs), veatchine‐type alkaloids and atisine‐type alkaloids. Fragmentation rules and key diagnostic fragment ions have been summarized, and possible pathways of fragmentation have been proposed. By accurate mass measurements within 5 ppm error for each ion, 30 C19‐diterpenoid alkaloids including 10 DDAs, 3 MDAs, 9 ADAs and 8 other type alkaloids, and 8 C20‐diterpenoid alkaloids including 4 veatchine‐type alkaloids and 4 atisine‐type alkaloids could be identified in a methanolic extract of Fuzi. Some isomers of aconite alkaloids were also differentiated. Based on the differences between their fragmentation pathways and special fragment ions, each type of aconite alkaloids was differentiated. Copyright © 2009 John Wiley & Sons, Ltd.
Glycerophospholipid profiling by high‐performance liquid chromatography/mass spectrometry using exact mass measurements and multi‐stage mass spectrometric fragmentation experiments in parallel
Authors: Hein Eva‐Maria , Blank Lars M. , Heyland Jan , Baumbach Jörg I. , Schmid Andreas , Hayen Heiko
Published: April 2009

A profiling method for glycerophospholipids (GPs) in biological samples was developed using reversed‐phase high‐performance liquid chromatography (RP‐HPLC) coupled to hybrid linear ion trap‐Fourier transform ion cyclotron resonance mass spectrometry (LIT‐FTICRMS) with electrospray ionization (ESI) in the negative ionization mode. The method allowed qualitative (identification and structure elucidation) and relative quantitative determination of various classes of GPs including phosphatidylcholines, phosphatidylethanolamines, phosphatidylinositols, phosphatidylserines, phosphatidic acids, phosphatidylglycerols, and cardiolipins in a single experiment. Chromatographic separation was optimized by the examination of different buffer systems and special emphasis was paid on the detection by ESI‐MS. The hybrid LIT‐FTICRMS system was operated in the data‐dependent mode, switching automatically between FTICRMS survey scans and LIT‐MS/MS experiments. Thereby, exact masses for elemental composition determination and fragmentation data for identification and assignment of fatty acid residues are provided at the same time. The low absolute instrumental limits of detection (0.05 pmol for phosphatidylglycerol to 1 pmol for phosphatidic acid) complemented by a linear dynamic range of 1.5 to 2.5 orders of magnitude facilitated the relative quantification of GP species in a lipid extract from Saccharomyces cerevisiae. The developed method is a valuable tool for in‐depth GP profiling of biological systems. Copyright © 2009 John Wiley & Sons, Ltd.
Surface Modification of Electrospun Polycaprolactone Nanofiber Meshes by Plasma Treatment to Enhance Biological Performance
Authors: Martins Albino , Pinho Elisabete D. , Faria Susana , Pashkuleva Iva , Marques Alexandra P. , Reis Rui L. , Neves Nuno M.
Published: April 2009

A critical aspect in the development of biomaterials is the optimization of their surface properties to achieve an adequate cell response. In the present work, electrospun polycaprolactone nanofiber meshes (NFMs) are treated by radio‐frequency (RF) plasma using different gases (Ar or O2), power (20 or 30 W), and exposure time (5 or 10 min). Morphological and roughness analysis show topographical changes on the plasma‐treated NFMs. X‐ray photoelectron spectroscopy (XPS) results indicate an increment of the oxygen‐containing groups, mainly OH and CO, at the plasma‐treated surfaces. Accordingly, the glycerol contact angle results demonstrate a decrease in the hydrophobicity of plasma‐treated meshes, particularly in the O2‐treated ones. Three model cell lines (fibroblasts, chondrocytes, and osteoblasts) are used to study the effect of plasma treatments over the morphology, cell adhesion, and proliferation. A plasma treatment with O2 and one with Ar are found to be the most successful for all the studied cell types. The influence of hydrophilicity and roughness of those NFMs on their biological performance is discussed. Despite the often claimed morphological similarity of NFMs to natural extracellular matrixes, their surface properties contribute substantially to the cellular performance and therefore those should be optimized.
Comparative Investigation on Acid Hydrolysis of Sweet Potato Starches with Different Amylopectin Chain‐Length
Authors: Genkina Natalia K. , Kiseleva Valentina I. , Noda Takahiro
Published: April 2009

The solubilization of starch from the new sweet potato cultivar “Quick Sweet” (QS) in 2.2 M aqueous HCl occurred at a much higher rate than that from normal sweet potato (NS). QS starch has an abnormal amylopectin chain‐length distribution with an unusually high percentage of short side‐chains. Two‐stage hydrolysis occurred in both cases. The apparent first‐order kinetic constants (k) were calculated for both stages of the hydrolytic process in both types of sweet potato starch. A more drastic difference between the investigated starches (k for QS and NS starches was 27.0×10‐2 d‐1 and 7.0×10‐2 d‐1, respectively) was observed for the first stage of the hydrolysis affecting the amorphous regions of starches whereas the rate for the second stage (the degradation of the crystalline part) for the starch from QS was only slightly higher. The role of the structural defectiveness of QS in decreasing the granular resistance to acid hydrolysis and increasing the absorptive properties of the granules for water molecules is discussed.
Effect of deviation of nuchal translucency measurements on the performance of screening for trisomy 21
Authors: Kagan K. O. , Wright D. , Etchegaray A. , Zhou Y. , Nicolaides K. H.
Published: April 2009

Objectives

To examine the effect of deviations in median nuchal translucency thickness (NT) and the spread in measurements on the performance of screening for trisomy 21 by maternal age and fetal NT, and by maternal age, fetal NT and maternal serum biochemistry.

Methods

We simulated the NT and multiples of the median values for pregnancy‐associated plasma protein‐A (PAPP‐A) and free β‐human chorionic gonadotropin (β‐hCG) for 500 000 euploid and 500 000 trisomy 21 pregnancies at 12 weeks of gestation. Detection rates for trisomy 21 and false‐positive rates were calculated without adjustments in NT and by adding or subtracting values ranging from 0.1 to 1.0 mm to each observed measurement. In addition, the effects of variation in the scatter of NT measurements were examined by applying a multiplicative factor ranging from 0.5 to 2 to the SD.

Results

The detection rate of trisomy 21 for a fixed false‐positive rate of 3% in screening by maternal age and fetal NT was 72%, and in screening by maternal age, fetal NT and serum free β‐hCG and PAPP‐A it was 86%. A consistent underestimate or overestimate in the measured NT reduced the detection rate of trisomy 21 for a fixed‐false positive rate. At a fixed screen‐positive cut‐off an underestimate in fetal NT reduced the detection rate whereas an overestimate in NT increased the false‐positive rate. A widening in the scatter of measurements had only a small impact on the detection rate but it caused a major increase in the false‐positive rate.

Conclusions

High performance of screening necessitates appropriate measurement of fetal NT. This paper demonstrates the effect of deviations in the median and SD of NT from the expected on the performance of screening and can form the basis of audit of results of individual sonographers. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Effects of parameter changes on the structure and properties of low‐density polyethylene foam
Authors: Zakaria Z. , Ariff Z.M. , Sipaut C.S.
Published: April 2009

Several parameters, such as crosslinking agent concentration, blowing agent concentration, and temperature, were varied to evaluate their effects on the structure and mechanical properties of low‐density polyethylene (LDPE) foams. Dicumyl peroxide (DCP) was used as crosslinking agent, while azodicarbonamide (ADC) was utilized as the blowing agent at different levels. The formulations were prepared by using a thermostatically controlled heated two‐roll mill and foamed by using a compression molding technique via a single‐stage foaming process at three foaming temperatures (165, 175, and 185°C). The resultant LDPE foams were characterized and found to have a closed cell structure. The density and gel content increased proportionally with crosslinking level, whereas density decreased when ADC level and foaming temperature were increased. Another characteristic evaluated was the foam cell size decreased when the crosslinking level and foaming temperature were increased. In contrast, increasing the ADC concentration only gave a maximum cell size increase up to 6 phr that decreased when 8 phr of ADC was used. Results also indicated that compression stress increased proportionally with DCP level and decreased when ADC concentration and foaming temperature were increased. Impact studies on the prepared foams showed that their ability to absorb impact energy decreased with increasing crosslinking level, foaming temperature, and blowing agent concentration. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers
Improved properties of cotton by atmospheric pressure plasma polymerization deposition of sericin
Authors: Jiang X.‐M. , Rui Y.‐N. , Chen G.‐Q.
Published: April 2009

Cotton fabric was exposed to an atmospheric pressure glow discharge (APGD) ignited by high voltage and helium. Ultrasonic atomization of an aqueous sericin solution injected as an aerosol into the APGD zone gave rise to the rapid deposition of a functionalized plasma polymer film. Sericin coating onto the cotton surface was confirmed by scanning electron microscopy, and the chemical composition was analyzed by Fourier transform infrared spectrophotometry and X‐ray photoelectron spectroscopy. It was found that the plasma power could affect the chemistry of the coating. The treated fabrics were tested for UV resistance, crease recovery angle, and water uptake. Results showed that these properties had been improved. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers
New insights into the compulsion to use tobacco from an adolescent case‐series
Authors: DiFranza Joseph R. , Ursprung W.W. Sanouri , Carson Alisha
Published: April 2009

Nicotine addiction is the most common preventable cause of premature death presenting during adolescence. No prior study has described the onset of this condition based on case histories. We used trained personnel to conduct individual semi‐structured interviews to obtain case histories from 50 adolescent and young adult current and former smokers.

Smokers experience a compulsion to use tobacco that spans a spectrum of severity from wanting, to craving, to needing. The compulsion is commonly experienced as originating foreign to the will of the smoker and recurs with a predictable periodicity that determines the latency from smoking one cigarette to wanting, craving or needing another. Novice smokers could experience latencies as lengthy as a few weeks, and more experienced smokers attributed their escalation in smoking frequency to the shortening of their latencies. Wanting, craving or needing tobacco, as described in this study, are pathognomonic for a compulsion to use tobacco.
Ist eine gesetzliche Impfpflicht ethisch zu rechtfertigen?
Authors: Marckmann Georg
Published: April 2009

Einleitung

Trotz überzeugender Argumente für die Durchführung aktiver Schutzimpfungen liegen die Durchimpfungsraten immer noch unter den angestrebten Werten. Damit wird das Potenzial der verfügbaren effektiven und sicheren Impfstoffe, d.h. die Möglichkeit zur Senkung der infektionsbedingten Morbidität und Mortalität nicht ausgeschöpft. Angesichts der guten Effektivität und auch Kosteneffektivität von Impfmaßnahmen stellt sich deshalb die Frage, ob Impfungen nicht per Gesetz vorgeschrieben werden sollten.
Quaternary reactivation of a basement structure in the Barreirinhas Basin, Brazilian Equatorial Margin
Authors: Almeida-Filho Raimundo , Rossetti Dilce F. , Miranda Fernando P. , Ferreira Francisco J. , Silva Clauzionor , Beisl Carlos
Published: April 2009

The Pirapemas Lineament is a remarkable 200-km-long, NE–SW trending structure in the Barreirinhas Basin, one of the several Brazilian coastal basins. This lineament splits the study area in two sectors of distinctive morphology, drainage patterns, and sedimentary covers. Terrain northward of the lineament presents a smooth topography with sub-parallel to sub-dendritic drainage patterns, whereas a dissected plateau characterized by incised valleys and rectangular drainage pattern occurs southward, suggesting a structural control by joints and faults. Geological field data, crossed with thermal luminescence (TL) and optically stimulated luminescence (OSL) dating, revealed that the surface southward of the lineament consists mostly of Miocene and late Pleistocene sedimentary deposits, represented by the Barreiras Formation and the Post-Barreiras sediments, respectively. In contrast, relatively younger sands mantle most of the northward terrain, as indicated by well-preserved paleodune deposits that grade into active aeolian dunes of the Lençóis Maranhenses National Park. Geomorphological and geological data analysis suggests that the northern sector is under the effect of subsidence, proving that the Pirapemas Lineament is an active agent modeling the landscape in the region. Geophysical data (gravity and seismic) confirm that such a structural feature is the surface expression of an active deep-seated basement fault.
Age dependence of plasma phospholipid fatty acid levels: potential role of linoleic acid in the age-associated increase in docosahexaenoic acid and eicosapentaenoic acid concentrations
Authors: de Groot Renate H. M. , van Boxtel Martin P. J. , Schiepers Olga J. G. , Hornstra Gerard , Jolles Jelle
Published: April 2009

Limited information is available with respect to the association between age and the plasma phospholipid fatty acid profile. Therefore we investigated the association between plasma phospholipid fatty acid status and age after correction for sex, smoking, alcohol use, BMI and fish intake. Plasma phospholipid fatty acid composition was measured and information on fish intake and other potential covariates was collected in 234 participants of the Maastricht Aging Study. The participants were healthy individuals of both sexes with an age range between 36 and 88 years. Hierarchical linear regression analyses were applied to study the relationship between age and fatty acid concentrations. After correction for fish consumption and other relevant covariates, a significant positive relationship was observed between age of the subjects and their plasma phospholipid concentrations of DHA (22 : 6n-3,P = 0·006) and EPA (20 : 5n-3;P = 0·001). Age contributed 2·3 and 3·9 % to the amount of explained variance, respectively. The highern-3 long-chain PUFA status at advanced age was confirmed by lower concentrations of their putative ‘shortage marker’ Osbond acid (ObA, 22 : 5n-6;P = 0·022 for the relationship with age after correction for covariates and fish intake,R20·022). Concentrations of linoleic acid (LA; 18 : 2n-6) were negatively associated with age (P < 0·001;R20·061). In conclusion, DHA and EPA concentrations appeared to be higher in older age groups, partly because of a higher fish intake and partly because of another age-associated mechanism, possibly involving the well-known competition with LA.
Self-organization in a driven dissipative plasma system
Authors: SHAIKH DASTGEER , DASGUPTA B. , HU Q. , ZANK G. P.
Published: April 2009

We perform a fully self-consistent three-dimensional numerical simulation for a compressible, dissipative magnetoplasma driven by large-scale perturbations, that contain a fairly broad spectrum of characteristic modes, ranging from largest scales to intermediate scales and down to the smallest scales, where the energy of the system is dissipated by collisional (ohmic) and viscous dissipations. Additionally, our simulation includes nonlinear interactions amongst a wide range of fluctuations that are initialized with random spectral amplitudes, leading to the cascade of spectral energy in the inertial range spectrum, and takes into account large-scale as well as small-scale perturbations that may have been induced by the background plasma fluctuations, as well as the non-adiabatic exchange of energy leading to the migration of energy from the energy-containing modes or randomly injected energy driven by perturbations and further dissipated by the smaller scales. Besides demonstrating the comparative decays of the total energy and the dissipation rate of the energy, our results show the existence of a perpendicular component of the current, thus clearly confirming that the self-organized state is non-force free.