bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical cross‐linking with NHS esters: a systematic study on amino acid reactivities
Authors: Mädler Stefanie , Bich Claudia , Touboul David , Zenobi Renato 
Published: January 2009

AbstractStructure elucidation of tertiary or quaternary protein structures by chemical cross‐linking and mass spectrometry (MS) has recently gained importance. To locate the cross‐linker modification, dedicated software is applied to analyze the mass or tandem mass spectra (MS/MS). Such software requires information on target amino acids to limit the data analysis time. The most commonly used homobifunctional N‐hydroxy succinimide (NHS) esters are often described as reactive exclusively towards primary amines, although side reactions with tyrosine and serine have been reported. Our goal was to systematically study the reactivity of NHS esters and derive some general rules for their attack of nucleophilic amino acid side chains in peptides. We therefore studied the cross‐linking reactions of synthesized and commercial model peptides with disuccinimidyl suberate (DSS). The first reaction site in all cases was expectedly the α‐NH2‐group of the N‐terminus or the ε‐NH2‐group of lysine. As soon as additional cross‐linkers were attached or loops were formed, other amino acids were also involved in the reaction. In addition to the primary amino groups, serine, threonine and tyrosine showed significant reactivity due to the effect of neighboring amino acids by intermediate or permanent Type‐1 cross‐link formation. The reactivity is highly dependent on the pH and on adjacent amino acids. Copyright © 2009 John Wiley & Sons, Ltd.
Effects of acute agonist treatment on subcellular distribution of κ opioid receptor in rat spinal cord
Authors: Wang Yulin , Xu Wei , Huang Peng , Chavkin Charles , Van Bockstaele Elisabeth J. , Liu‐Chen Lee‐Yuan 
Published: January 2009

AbstractWe investigated whether acute treatment with agonists affected the subcellular distribution of κ opioid receptor (KOPR) in the dorsal horn of the rat lumbar spinal cord by using immunoelectron microscopy. Rats were injected intrathecally (i.t.) with U50,488H (100 nmole), dynorphin A(1–17) (15 nmole), or vehicle. The doses chosen have been shown to induce antinociception. Rats were perfused transcardially 30 min later, and lumbar spinal cords were removed and processed for electron microscopic analysis. KOPR was stained with KT‐2, a specific polyclonal antibody against the rat/mouse KOPR(371–380) peptide, followed by gold‐labeled secondary antibody and silver intensification. The silver grains were present in axons, terminals, dendrites, and somata, and the association with plasma membranes was quantified in dendrites, because KOPR immunoreactivity was most frequently observed in these profiles. In vehicle‐treated rats, ∼27% of KOPR immunoreactivity was associated with plasma membranes. U50,488H, i.t., did not cause a significant change in the percentage of KOPR present on plasma membranes, whereas dynorphin A, i.t., significantly decreased cell surface KOPR to ∼19%. In summary, these data indicate that U50,488H and dynorphin A differentially regulate the subcellular distribution of endogenous KOPR. © 2009 Wiley‐Liss, Inc.
Putting first things first: Outcome and process focus in knowledge work teams
Authors: Woolley Anita Williams 
Published: January 2009

AbstractThis paper presents a new perspective on the management of outcomes and processes in a knowledge team's work. Knowledge teams frequently face complex, open‐ended tasks for which the a priori specification of goals and work processes is not possible. Such teams must define these work elements themselves; emphasizing one over the other can lead a team to become either outcome‐or process‐focused, with implications for the level at which they identify their activities and the flexibility with which they conduct work. A survey study of student teams and a field study of organizational teams test the effects of outcome versus process focus on performance. Consistent with prior findings, the first study demonstrates that outcome focus is positively related to performance on complex, open‐ended tasks and that team members' level of action identification mediates the effects of outcome and process focus on performance. Action research conducted as part of the second study demonstrates the importance of early events in a team's life cycle and the challenge for managers who hope to influence their teams to have a greater degree of focus on outcomes over process. Copyright © 2009 John Wiley & Sons, Ltd.
Occupational embeddedness and job performance
Authors: Ng Thomas W. H. , Feldman Daniel C. 
Published: January 2009

AbstractWhile researchers have recently focused their attention on organizational embeddedness, occupational embeddedness has received little theoretical and empirical attention. Using multisource data on 162 employees in multiple jobs and organizations, we found that occupational embeddedness is positively related to both task performance and creativity and is negatively related to counterproductive work behavior, even after controlling for the effects of organizational embeddedness. In addition, we found that trait affect moderated the relationships of occupational embeddedness to job performance. Occupational embeddedness was more strongly related to counterproductive work behavior when trait negative affect was high, while occupational embeddedness was more strongly related to both citizenship behavior and creativity when trait positive affect was high. Results also indicated that the various components of occupational embeddedness had different effects on job outcomes. Fit had a strong positive effect on core task performance, links had a positive effect on creativity, and sacrifice had a small positive effect on citizenship behavior. The article concludes with a discussion of implications for future research and management practice. Copyright © 2009 John Wiley & Sons, Ltd.
Role of El Niño/La Niña in temperature extremes over India
Authors: Revadekar J. V. , Kothawale D. R. , Rupa Kumar K. 
Published: January 2009

AbstractEl Niño and La Niña are well known to be associated with significant monthly/seasonal climate anomalies at many places around the globe. Therefore, an attempt is made in this study to analyse objectively defined indices of observed temperature extremes over India, in terms of their frequencies and intensities, in relation to El Niño/La Niña events using daily station data for minimum and maximum temperature at 121 well‐distributed stations for the period 1970–2003.There is a characteristic change in the El Niño southern oscillation (ENSO)‐associated extremes with the onset of the summer monsoon in June; El Niño is associated with lower frequency of warm extremes during the pre‐monsoon months and with higher frequency of warm extremes during the monsoon and post‐monsoon season. The opposite features are seen in the case of La Niña. In addition, El Niño leads to an increase in extreme highest temperature, whereas La Niña leads to a decrease, during monsoon and post‐monsoon months. Strong antecedent relationship exists between ENSO index and various seasonal extreme temperature indices over the Indian region, indicating potential for long‐range prediction of temperature extremes. Copyright © 2009 Royal Meteorological Society
Endoscopic CO2 laser cricopharyngeal myotomy
Authors: Pitman Michael , Weissbrod Philip 
Published: January 2009

AbstractObjectives:Over the past 10 years, endoscopic cricopharyngeal myotomy laser surgery has been proposed as an alternative to transcervical cricopharyngeal myotomy. We will describe the technique and review the literature so that it may gain credence as a viable option for the treatment of cricopharyngeal achalasia.Methods:A literature review of endoscopic and transcervical cricopharyngeal myotomy will be performed. The technical aspects of endoscopic cricopharyngeal myotomy will be presented and accompanied by intraoperative photographs, illustrations, and an online video demonstration.Results:Endoscopic cricopharyngeal myotomy is a well‐tolerated procedure with low morbidity and good outcomes. It can be performed by surgeons who are comfortable with transoral laryngopharyngeal laser surgery.Conclusions:Endoscopic cricopharyngeal myotomy is a viable alternative to classic transcervical cricopharyngeal myotomy with equivalent outcomes and comparable if not less morbidity. Laryngoscope, 119:45–53, 2009
Issues surrounding fish as a source of omega‐3 long‐chain polyunsaturated fatty acids
Authors: Tocher Douglas 
Published: January 2009

AbstractFish are a virtually unique, rich source of omega‐3 long‐chain polyunsaturated fatty acids (ω3 LC‐PUFA) in the human diet. This article describes the origins of ω3 LC‐PUFA in fish and the increasingly important role of aquaculture in the provision of fish for human consumption. It also highlights the major issues currently facing aquaculture, focusing on sustainability, driven by the urgent need to replace traditional fish oil and meal in formulated diets, and safety, driven by the requirement to reduce feed‐derived contaminants.
Standard Reference Materials to support measurement of fatty acids
Authors: Sander Lane , Schantz Michele , Sharpless Katherine , Wise Stephen 
Published: January 2009

AbstractThe National Institute of Standards and Technology offers a variety of natural‐matrix and solution‐based Standard Reference Materials (SRM) that are characterized for fatty acid composition. The natural‐matrix SRM are intended primarily for use as control materials, but other uses include method validation, the development of new analytical methods, and use as a component in achieving traceability of measurements. The use of complex‐matrix reference materials for instrument calibration is not recommended; solution calibrants are better suited to this task. In addition to calibration, solution SRM can be used as spiking solutions for fortification of samples, in studying extraction recoveries, for developing chromatographic separations, and as authentic standards for identifying constituents in more complex‐matrix extracts. The use of SRM to support the measurement of fatty acids is relevant to a broad spectrum of applications including compliance with and accuracy of nutritional labeling, food manufacturing tolerances (e. g., infant formulas), traceability of measurements for food exports, clinical nutritional measurements, and characterization of alternative energy sources (e. g., biodiesel). Currently, nearly 30 SRM are available with certified, reference, and information values reported for fatty acids. Additional SRM are under development that will complement these reference materials by providing fatty acid profiles in different types of matrices.
Double‐Hydrophilic and Amphiphilic Block Copolymers Synthesized by RAFT Polymerization of Monomers Carrying Chiral Amino Acids
Authors: Mori Hideharu , Matsuyama Motonobu , Endo Takeshi 
Published: January 2009

AbstractDouble‐hydrophilic and amphiphilic block copolymers with characteristic chiroptical properties (L‐L and L‐D types) were synthesized by RAFT polymerization. Five N‐acryloylamino acids with different hydrophilicity and chirality were employed, which included A‐(L)Phe‐OMe, A‐(L)Phe‐OH, A‐(L)Ala‐OH, and their D‐forms [A‐(D)Phe‐OH and A‐(D)Ala‐OH], respectively. The RAFT polymerization of the unprotected monomer using the hydrophobic and hydrophilic macro‐chain transfer agents provided well‐defined block copolymers. Chiroptical properties and assembled structures were evaluated by CD, UV‐vis and DLS measurements.magnified image
Block Copolymer Synthesis via Chemoselective Stepwise Coupling Reactions
Authors: Bellas Vasilios , Rehahn Matthias 
Published: January 2009

AbstractChemoselective stepwise coupling between living polymers and a heterobifunctional‐linking agent is shown to be a powerful methodology for block copolymer synthesis. This synthetic strategy is based on the quantitative formation of end‐functionalized precursors in the first coupling step. These end‐functionalized precursors were reacted with further living polymers, thereby producing well‐defined diblock copolymers, triblock terpolymers and a tetrablock quaterpolymer. The behavior of chloro(chloromethyl)dimethylsilane, chloro(3‐chloropropyl)dimethylsilane and (bromomethyl)chlorodimethylsilane against macroanions of different reactivity, prepared through living anionic polymerization, was studied. It is demonstrated that the applicability range of the presented methodology is exceptionally wide, and expands the limits of conventional methods based on sequential monomer addition considerably.magnified image
Self‐Assembly and Dynamics of Polypeptides
Authors: Floudas George , Spiess Hans Wolfgang 
Published: January 2009

AbstractThis work highlights the results of recent efforts to understand the hierarchical self‐assembly and dynamics of polypeptides with the aid of different NMR techniques, X‐ray scattering, and dielectric spectroscopy. The concerted application of these techniques sheds light on the origin of the glass transition, the persistence of theα‐helical peptide secondary motif, and the effects of topology and packing on the type and persistence of secondary structures. With respect to the freezing of the dynamics at the liquid‐to‐glass temperature it was found that the origin of this effect is a network of defected hydrogen bonds. The presence of defected hydrogen‐bonded regions reduces the persistence length ofα‐helices. Block copolypeptides provide means to manipulate both the type and persistence of peptide secondary structures.magnified image
Blow up for a Cauchy viscoelastic problem with a nonlinear dissipation of cubic convolution type
Authors: Yu Shengqi , Wang Mingxin , Liu Wenjun 
Published: January 2009

AbstractIn this paper, we consider a Cauchy viscoelastic problem with a nonlinear source of polynomial type and a nonlinear dissipation of cubic convolution type involving a singular kernel. Under suitable conditions on the initial data and the relaxation functions, it is proved that the solution of this particular problem blows up in finite time. Copyright © 2009 John Wiley & Sons, Ltd.
Magnetic resonance elastography with a phased‐array acoustic driver system
Authors: Mariappan Yogesh K. , Rossman Phillip J. , Glaser Kevin J. , Manduca Armando , Ehman Richard L. 
Published: January 2009

AbstractDynamic MR elastography (MRE) quantitatively maps the stiffness of tissues by imaging propagating shear waves in the tissue. These waves can be produced from intrinsic motion sources (e.g., due to cardiac motion), from external motion sources that produce motion directly at depth in tissue (e.g., amplitude‐modulated focused ultrasound), and from external actuators that produce motion at the tissue surface that propagates into the tissue. With external actuator setups, typically only a single transducer is used to create the shear waves, which in some applications might have limitations due to shadowing and attenuation of the waves. To address these limitations, a phased‐array acoustic driver system capable of applying independently controlled waveforms to each channel was developed and tested. It was found that the system produced much more uniform illumination of the object, improving the quality of the elastogram. It was also found that the accuracy of the stiffness value of any arbitrary region of interest could be improved by obtaining maximal shear wave illumination with the phased array capability of the system. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Variation in the shape of pulsed arterial spin labeling kinetic curves across the healthy human brain and its implications for CBF quantification
Authors: Gallichan Daniel , Jezzard Peter 
Published: January 2009

AbstractArterial spin labeling (ASL) uses proximally inverted blood water spins as an endogenous contrast agent to measure blood perfusion in tissue. In this work pulsed ASL was used to measure the kinetic curves of cerebral blood flow (CBF) across eight anatomically based regions of interest (ROIs) in five normal healthy subjects. CBF estimates based on these data were compared when obtained using a single inversion time versus fitting a kinetic model to all 10 measured inversion times. CBF estimates were also compared when fitting to the 10 inversion time data using a standard two‐parameter approach (CBF and bolus arrival time) or a more recently proposed three‐parameter model (CBF, bolus arrival time, and arrival time dispersion). Variations in the shape of the kinetic curve were found across the brain that were consistent across subjects. The arrival time in the occipital ROI was found to be long enough to lead to underestimation of the CBF when using a single inversion time of 1.5 s. In four out of the eight ROIs there was significant underestimation of CBF using the standard two‐parameter model compared to the three‐parameter approach. These results have important implications for the development of a robust, quantitative ASL protocol. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Eddy‐current compensated diffusion weighting with a single refocusing RF pulse
Authors: Finsterbusch Jürgen 
Published: January 2009

AbstractA modification of the Stejskal‐Tanner diffusion‐weighting preparation with a single refocusing RF pulse is presented which involves three gradient lobes that can be adjusted to null eddy currents with any given decay rate to reduce geometric distortions in diffusion‐weighted echo‐planar imaging (EPI). It has a very similar compensation performance as the commonly used double‐spin‐echo preparation but (i) is less sensitive to flip angle imperfections, e.g. along the slice profile, and B1 inhomogeneities and (ii) can yield shorter echo times for moderate b values, notably for longer echo trains as required for higher spatial resolution. It therefore can provide an increased signal‐to‐noise ratio as is simulated numerically and demonstrated experimentally in water phantoms and the human brain for standard EPI (2.0 × 2.0 mm2) and high‐resolution EPI of inner field‐of‐views using 2D‐selective RF excitations (0.5 × 1.0 mm2). Thus, the presented preparation may help to overcome current limitations of diffusion‐weighted EPI, in particular at high static magnetic fields. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Non‐uniqueness of critical state line in compression and extension conditions
Authors: Yin Zhen‐Yu , Chang Ching S. 
Published: January 2009

AbstractExperimental evidence has indicated that the critical state line determined from undrained compression tests is not identical to that determined from undrained extension tests. The purpose of this paper is to investigate a modelling method that accounts for the non‐uniqueness of critical state lines in the compression and the extension testing conditions. Conventional elastic–plastic cap models can predict only a unique critical state line for the compression and the extension tests. A new micromechanical stress–strain model is developed considering explicitly the location of critical state line. The model is then used to simulate undrained triaxial compression and extension tests performed on isotropically consolidated samples with different over‐consolidated ratios. The predictions are compared with experimental results as well as that predicted by models with kinematic hardening of yield surface. All simulations demonstrate that the proposed micromechanical approach is capable of modelling the undrained compression and the undrained extension tests. Copyright © 2009 John Wiley & Sons, Ltd.
A domain decomposition method for discontinuous Galerkin discretizations of Helmholtz problems with plane waves and Lagrange multipliers
Authors: Farhat Charbel , Tezaur Radek , Toivanen Jari 
Published: January 2009

AbstractA nonoverlapping domain decomposition (DD) method is proposed for the iterative solution of systems of equations arising from the discretization of Helmholtz problems by the discontinuous enrichment method. This discretization method is a discontinuous Galerkin finite element method with plane wave basis functions for approximating locally the solution and dual Lagrange multipliers for weakly enforcing its continuity over the element interfaces. The primal subdomain degrees of freedom are eliminated by local static condensations to obtain an algebraic system of equations formulated in terms of the interface Lagrange multipliers only. As in the FETI‐H and FETI‐DPH DD methods for continuous Galerkin discretizations, this system of Lagrange multipliers is iteratively solved by a Krylov method equipped with both a local preconditioner based on subdomain data, and a global one using a coarse space. Numerical experiments performed for two‐ and three‐dimensional acoustic scattering problems suggest that the proposed DD‐based iterative solver is scalable with respect to both the size of the global problem and the number of subdomains. Copyright © 2009 John Wiley & Sons, Ltd.
Compact difference schemes for heat equation with Neumann boundary conditions
Authors: Sun Zhi‐Zhong 
Published: January 2009

AbstractIn this article, two recent proposed compact schemes for the heat conduction problem with Neumann boundary conditions are analyzed. The first difference scheme was proposed by Zhao, Dai, and Niu (Numer Methods Partial Differential Eq 23, (2007), 949–959). The unconditional stability and convergence are proved by the energy methods. The convergence order is O(τ2 + h2.5) in a discrete maximum norm. Numerical examples demonstrate that the convergence order of the scheme can not exceeds O(τ2 + h3). An improved compact scheme is presented, by which the approximate values at the boundary points can be obtained directly. The second scheme was given by Liao, Zhu, and Khaliq (Methods Partial Differential Eq 22, (2006), 600–616). The unconditional stability and convergence are also shown. By the way, it is reported how to avoid computing the values at the fictitious points. Some numerical examples are presented to show the theoretical results. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
Finite element analysis of thermally coupled nonlinear Darcy flows
Authors: Zhu Jiang 
Published: January 2009

AbstractWe consider a coupled system describing nonlinear Darcy flows with temperature dependent viscosity and with viscous heating. We first establish existence, uniqueness, and regularity of the weak solution of the system of equations. Next, we decouple the coupled system by a fixed point algorithm and propose its finite element approximation. Finally, we present convergence analysis with an error estimate between continuous solution and its iterative finite element approximation.© 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2010
Does perception of the childbirth experience predict women's early parenting behaviors?
Authors: Bryanton Janet , Gagnon Anita J. , Hatem Marie , Johnston Celeste 
Published: January 2009

AbstractEvidence regarding the predictors of positive parenting behaviors in the early transition to parenting is inconsistent and limited. In this prospective, cohort study, we examined whether women's perceptions of their childbirth experience, as well as selected demographic, obstetrical, and psychosocial variables, predicted positive parenting behaviors at 1 month postpartum in 175 Canadian mothers. Women's birth experience did not predict early parenting behaviors, however being better educated and having a vaginal birth did. Excellent partner support and maternal mental health were also significantly associated with positive parenting at 1 month. Nurses have a responsibility to assess women for possible risks for sub‐optimal parenting, based on the predictors found, and intervene to enhance parenting behaviors. © 2009 Wiley Periodicals, Inc. Res Nurs Health 32:191–203, 2009