bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution of the Field‐Emission Properties of Individual Multiwalled Carbon Nanotubes Submitted to Temperature and Field Treatments
Authors: Purcell S. T. , Vincent P. , Rodriguez M. , Journet C. , Vignoli S. , Guillot D. , Ayari A. 
Published: June 2006

AbstractField‐emission (FE) electron and ion microscopies (FEM and FIM),I(V) characteristics, and FE energy spectroscopy (FEES) measurements have been made on individual multiwalled carbon nanotubes (MWNTs) at various stages of their evolution under various thermal and field treatments. Before the highest temperature treatments, the FE is produced by nanometer‐scale structures that have specific and known characteristics such as individual peaks in the total energy distributions (TEDs), highly curved Fowler–Nordheim (FN) plots, and strong local heating due to the Nottingham effect. After cleaning at up to 1600 K, the TEDs approached the well‐known form for FN tunneling from a free electron gas. As previously reported, they revealed and quantified strong heating at high FE currents induced by Joule heating along the MWNT. The TEDs gave a quantitative simultaneous measure of the temperature at the end of the MWNT,TA(which reached up to 2000 K), and its electrical resistanceR, thus allowing the determination ofR(TA).R(TA) decreased by ca. 70 % asTAincreased from 300 to 2000 K, indicating a nonmetallic behavior of the MWNT. Changes in the MWNT length due to the induced high temperatures above 1600 K could be followed using theI(V) characteristics. The high temperatures were accompanied by light emission due to incandescence for which the optical spectra was found to follow the Planck distribution. With the simultaneous measurements ofTAandR, the 1D heating problem could be reliably simulated to estimate the dependence of both electrical and thermal conductivities on temperature. This heating results in an excellent current stability by continuous desorption, and defines the maximum nanotube currents for high‐current applications
Differential expression of polycomb repression complex 1 (PRC1) members in the developing mouse brain reveals multiple complexes
Authors: Vogel Tanja , Stoykova Anastassia , Gruss Peter 
Published: June 2006

AbstractPolycomb group (PcG) genes are regulators of body segmentation and cell growth, therefore being important players during development. PcG proteins form large complexes (PRC) that fulfil mostly repressive regulative functions on homeotic gene expression. Although expression of PcG genes in the brain has been noticed, the involvement of PcG genes in the processes of brain development is not understood. In this study, we analysed the expression patterns of PRC1 complex members to reveal PcG proteins that might be relevant for mouse brain development. Using in situ hybridisation, we show PRC1 activity in proliferative progenitor cells during neurogenesis, but also in maturated neuronal structures. PRC1 complex compositions vary in a spatial and temporal controlled manner during mouse brain development, providing cellular tools to act in different developmental contexts of cell proliferation, cell fate determination, and differentiation. Developmental Dynamics 235:2574–2585, 2006. © 2006 Wiley‐Liss, Inc.
Pertussis toxin activates adult and neonatal naive human CD4+ T lymphocytes
Authors: Tonon Sandrine , Badran Bassam , Benghiat Fleur Samantha , Goriely Stanislas , Flamand Véronique , Willard‐Gallo Karen , Willems Fabienne , Goldman Michel , De Wit Dominique 
Published: June 2006

AbstractPertussis toxin (PTX) is known to be mitogenic for T lymphocytes, but its direct action on naive human T cells has not been specified. Herein, we show that PTX induces the proliferation of purified adult CD45RA+CD4+ T cells independently of its ADP‐ribosyltransferase activity. PTX directly induces TNF‐α and IL‐2 mRNA expression, modulates the level of several cell surface receptors and induces Forkhead box p3 (Foxp3) protein accumulation in naive CD4+ T cells. Addition of autologous dendritic cells was found to be required for the production of high levels of IFN‐γ by PTX‐stimulated naive T cells. These effects of PTX occurred in conjunction with activation of NF‐κB and NFAT transcription factors. Overall, responses of neonatal CD4+ T cells to PTX were similar to those of adult CD45RA+CD4+ naive T cells except for their blunted CD40 ligand up‐regulation. We suggest that the adjuvant properties of PTX during primary cell‐mediated immune responses involve a direct action on naive T lymphocytes in addition to activation of antigen‐presenting cells.
B*2707 differs in peptide specificity from B*2705 and B*2704 as much as from HLA‐B27 subtypes not associated to spondyloarthritis
Authors: Gómez Patricia , Montserrat Verónica , Marcilla Miguel , Paradela Alberto , de Castro José A. López 
Published: June 2006

AbstractHLA‐B*2707 is associated with ankylosing spondylitis in most populations. Like the non‐associated allotypes B*2706 and B*2709, it lacks Asp116 and shows preference for peptides with nonpolar C‐terminal residues. The relationships between the peptide specificity of B*2707 and those of the disease‐associated B*2705 and the non‐associated subtypes were analyzed by determining the overlap between the corresponding peptide repertoires, the sequence of shared and differential ligands, and by comparing allospecific T cell epitopes with peptide sharing. The B*2707‐bound repertoire was as different from that of B*2705 as from those of B*2706, B*2709, or the two latter subtypes from each other. Differences between B*2707 and B*2705 were based on their C‐terminal residue specificity and a subtle modulation at other positions. Differential usage of secondary anchor residues explained the disparity between the B*2707‐, B*2706‐, and B*2709‐bound repertoires. Similar differences in residue usage were found between B*2707 and both B*2704 and B*2706, as expected from the high peptide overlap between the two latter subtypes. T cell cross‐reaction paralleled peptide sharing, suggesting that many shared ligands conserve their alloantigenic features on distinct subtypes. Our results indicate that association of HLA‐B27 subtypes with ankylosing spondylitis does not correlate with higher peptide sharing among disease‐associated subtypes or with obvious peptide motifs.
Evidence for the opposing roles of different γδ T cell subsets in macrophage homeostasis
Authors: Tramonti Daniela , Andrew Elizabeth M. , Rhodes Kate , Newton Darren J. , Carding Simon R. 
Published: June 2006

AbstractTo ensure invading pathogens are eliminated with minimal damage to host tissues it is essential that macrophage activation be tightly regulated. Previously we demonstrated that a subset of γδ T cells (Vγ1+) contributes to resolving pathogen‐induced immune responses by killing activated macrophages. However, the exaggerated macrophage response seen in infected Vγ1+ T cell‐deficient mice suggests that γδ T cells play a broader role in macrophage homeostasis and other subsets might promote macrophage activation. Using a macrophage:γδ T cell co‐culture system we have shown that γδ T cells increase the activity of macrophages activated in vivo by Listeria monocytogenes infection. In a dose‐dependent manner, γδ T cells up‐regulated production of cytokines (TNF‐α, IL‐6, IL‐10) and chemokines (MIP‐1α, MIP‐1β) by Listeria‐elicited macrophages. The ability to increase macrophage cytokine production was prominent among Vγ4+ γδ T cells. Reciprocally, Vγ4+ γδ T cells were activated by Listeria‐elicited macrophages, resulting in production of the anti‐inflammatory cytokine, IL‐10. γδ T cell adoptive transfer experiments showed that Vγ4+ T cells protected TCRδ–/– mice against Listeria‐induced liver injury and necrosis. These findings identify distinct and non‐overlapping roles for γδ T cell subsets in regulating macrophage function during pathogen‐induced immune responses.
Novel Synthetic Strategy Towards Taxol by Macrocyclization Reaction – Conformational Requirement of Ring A
Authors: Canesi Sylvain , Berthiaume Gilles , Deslongchamps Pierre 
Published: June 2006

AbstractThe synthesis of a completely substituted ring A of Taxol is reported and it is shown that the C13‐OP group must have a β configuration to succeed in the formation of 12‐membered rings, a requisite for the construction of the B and C rings of Taxol by a macrocyclization step. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Outage probability in multiple antenna systems
Authors: Jorswieck Eduard A. , Boche Holger 
Published: June 2006

AbstractMultiple transmit antennas improve the ergodic and outage capacity of wireless systems. Spatial properties of the channel including the transmit antenna array affect the optimum transmission strategy as well as the achievable capacity and average throughput. First, we study the outage probability of a multiple input single output (MISO) system with perfect channel state information (CSI) at the receiver under different types of CSI at transmitter and with transmit antenna correlation. We prove the conjecture given in Telatar's seminal paper and complete the analysis of the optimum transmit strategy without CSI at the transmitter and uncorrelated antennas. Furthermore, we show how the impact of correlation on the outage probability depends on the transmission rate and SNR. We show that the behaviour of the outage probability differs from the behaviour of the ergodic capacity. In terms of ergodic capacity there are clear instructions what is the optimum transmission strategy and what is the impact of correlation. In contrast, the outage probability behaves chameleonic. If the transmitter is aware of the channel correlation matrices, the optimum transmit strategy is to transmit along the eigenvectors of the known correlation matrix. The remaining power allocation problem is difficult since it is a non‐convex optimisation problem. However, necessary conditions characterise the optimal allocation. Finally, we analyse the outage probability for the general multiple input multiple output (MIMO) system with spatially correlated transmit and receive antennas in asymptotic high and low SNR regime. The theoretical results are illustrated by numerical simulations. Copyright © 2005 AEIT.
Extension of domain‐free discretization method to simulate compressible flows over fixed and moving bodies
Authors: Zhou C. H. , Shu C. , Wu Y. Z. 
Published: June 2006

AbstractThis paper is the first endeavour to present the local domain‐free discretization (DFD) method for the solution of compressible Navier–Stokes/Euler equations in conservative form. The discretization strategy of DFD is that for any complex geometry, there is no need to introduce coordinate transformation and the discrete form of governing equations at an interior point may involve some points outside the solution domain. The functional values at the exterior dependent points are updated at each time step to impose the wall boundary condition by the approximate form of solution near the boundary. Some points inside the solution domain are constructed for the approximate form of solution, and the flow variables at constructed points are evaluated by the linear interpolation on triangles. The numerical schemes used in DFD are the finite element Galerkin method for spatial discretization and the dual‐time scheme for temporal discretization. Some numerical results of compressible flows over fixed and moving bodies are presented to validate the local DFD method. Copyright © 2006 John Wiley & Sons, Ltd.
Pseudo‐characteristic formulation and dynamic boundary conditions for computational aeroacoustics
Authors: Lu Shang‐Yi , Sagaut Pierre 
Published: June 2006

AbstractThe present paper deals with the use of the pseudo‐characteristic formulation of the Navier–Stokes and Euler equations recently introduced by Sesterhenn (Comput. Fluid. 2001; 30:37–67) for the simulation of acoustic wave propagation. The emphasis is put on the formulation of an efficient method on structured curvilinear grids, along with the definition and implementation of efficient boundary conditions. The cases of inflow, outflow, rigid/compliant walls and walls with prescribed impedance are addressed. The proposed boundary conditions are assessed on generic cases. The pseudo‐characteristic formulation enables a straightforward and optimal use of high‐order upwind dispersion‐relation‐preserving schemes, yielding an efficient method. Copyright © 2006 John Wiley & Sons, Ltd.
Parallel solution of lifting rotors in hover and forward flight
Authors: Allen C. B. 
Published: June 2006

AbstractAn implicit unsteady, multiblock, multigrid, upwind solver including mesh deformation capability, and structured multiblock grid generator, are presented and applied to lifting rotors in both hover and forward flight. To allow the use of very fine meshes and, hence, better representation of the flow physics, a parallel version of the code has been developed. It is demonstrated that once the grid density is sufficient to capture enough turns of the tip vortices, hover exhibits oscillatory behaviour of the wake, even using a steady formulation. An unsteady simulation is then presented, and detailed analysis of the time‐accurate wake history is performed and compared to theoretical predictions. Forward flight simulations are also presented and, again, grid density effects on the wake formation investigated. Parallel performance of the code using up to 1024 CPU's is also presented. Copyright © 2006 John Wiley & Sons, Ltd.
A theoretical framework for TTO valuations of health
Authors: Buckingham Ken , Devlin Nancy 
Published: June 2006

AbstractThis paper proposes a theoretical framework, drawing on Hicks utility theory, for the Time Trade‐off (TTO) method conventionally used to value health states. We briefly describe that theory and posit four distinctive TTO valuation approaches suggested by it: each of compensating variation and equivalent variation for both gains and losses in health, with valuation of health states in each case derived from trade‐offs between health and length of life. Recent developments and research on TTO valuation are placed in the context of this framework. Copyright © 2006 John Wiley & Sons, Ltd.
Informing the efficient use of health care and health care research resources ‐ the case of screening for abdominal aortic aneurysm in Sweden
Authors: Henriksson Martin , Lundgren Fredrik , Carlsson Per 
Published: June 2006

AbstractBackground: An analytical framework using Bayesian decision theory and value‐of‐information analysis has recently been advocated for the economic evaluation of health technologies. The purpose of this study was to apply this framework to screening for abdominal aortic aneurysm (AAA) in Sweden and to compare the conclusions from this study with the conclusions presented in an assessment performed by the Swedish Council of Technology Assessment (SBU).Methods: A probabilistic decision‐analytical model was developed to establish the cost–effectiveness of a screening programme for AAA relative to current clinical practice and to calculate the value‐of‐information.Results: The cost per quality‐adjusted life‐year for screening was €9700. The expected value of perfect information for the assessment of overall cost–effectiveness was low, suggesting little benefit in conducting further research. Expected value of perfect partial information indicated that rupture probabilities were associated with the highest uncertainty. By contrast, the SBU report concluded there was limited evidence of cost–effectiveness and proposed further research.Conclusion: The investigated screening programme for AAA is likely to be cost–effective and conducting another clinical trial is unlikely to add much valuable information to this decision problem. These recommendations contrast with the vaguer recommendations from SBU that more evidence is required of costs–effectiveness. Copyright © 2006 John Wiley & Sons, Ltd.
Dynamic MR perfusion and proton MR spectroscopic imaging in sturge‐weber syndrome: Correlation with neurological symptoms
Authors: Lin Doris D.M. , Barker Peter B. , Hatfield Laura A. , Comi Anne M. 
Published: June 2006

AbstractPurposeTo investigate physiological alterations in Sturge‐Weber syndrome (SWS) using MR perfusion imaging (PWI) and proton spectroscopic imaging (MRSI), and their association with neurological status.Materials and MethodsSix consecutive patients with a clinically established diagnosis of SWS underwent MRI using a 1.5 Tesla scanner. The protocol consisted of conventional anatomic scans, dynamic PWI, and multislice MRSI. A pediatric neurologist evaluated the neurological scores, and the imaging results were correlated with neurological scores using nonparametric correlation analysis.ResultsTwo patients had classic neuroimaging findings of unilateral cerebral atrophy with corresponding leptomeningeal enhancement and hypoperfusion (prolonged mean transit time). Two patients had bilateral disease, and two had normal symmetric perfusion. Among clinical measures, the highest correlation was between hemiparesis index and hypoperfused tissue volume (Spearman's correlation coefficient, ρ = 0.943, P < 0.05). There was also a trend of correlation, although not statistically significant (P = 0.06), between the hemiparesis score and the NAA/Cr ratio in the mid to posterior centrum semiovale, lateral gray matter (GM), and splenium.ConclusionIn SWS, PWI indicates cerebral hypoperfusion predominantly due to impaired venous drainage, with only the most severely affected regions in some patients also showing arterial perfusion deficiency. The extent and severity of the perfusion abnormality and neuronal loss/dysfunction reflect the severity of neurological symptoms and disability, and the highest correlation is found with the degree of hemiparesis. These parameters may be useful as quantitative measures of disease burden; however, further studies in larger number of patients (and with a more homogeneous age range) are required to confirm the preliminary findings reported here. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Sodium Hydride/Trialkylaluminum Complexes for the Controlled Anionic Polymerization of Styrene at High Temperature
Authors: Carlotti Stéphane , Menoret Stephane , Desbois Philippe , Nissner Norbert , Warzelhan Volker , Deffieux Alain 
Published: June 2006

AbstractSummary: A new generation of anionic initiators (butyllithium free), based on trialkylaluminum and a readily available alkali metal hydride, has been developed for the control of styrene polymerization at high temperature. Triisobutylaluminum and sodium hydride form heterocomplexes that are efficient for the initiation of styrene polymerization at 100 °C in toluene or in bulk. To be active under such conditions, these systems require the presence of an excess of metal hydride with respect to AlR3 ([Al]/[Na] < 1). PS chains are specifically initiated by the hydrides coming from NaH, and molar masses are controlled in the range 0.8 < [Al]/[Na] < 1. Fast exchange between dormant 1:1 and active 1:2 complexes (Al:Na), and ligand rearrangements within the 1:2 complex, can explain the observed results.Initiation of styrene with i‐Bu3Al/NaH systems.magnified imageInitiation of styrene with i‐Bu3Al/NaH systems.
Facile polyester surface functionalization via hydrolysis and cell‐recognizing peptide attachment
Authors: Sun Hui , Önneby Sara 
Published: June 2006

AbstractFacile surface modification of biodegradable polycaprolactone via alkali hydrolysis and subsequent attachment of a cell‐recognizing peptide to the hydrolysed polymer surface is reported. Surface hydrolysis was carried out in sodium hydroxide solution. The modification was studied with regard to hydrolysis time, temperature and alkaline concentration. A cell‐recognizing peptide was covalently attached to the hydrolysed polymer surface. Contact angle measurements, X‐ray photoelectron spectroscopy and ultraviolet spectroscopy were used to characterize the modified surface and to confirm the occurrence of the coupling reaction. Copyright © 2006 Society of Chemical Industry
Dietary intervention and oxidative phosphorylation capacity
Authors: Morava Eva , Rodenburg Richard , van Essen Heidi Zweers , De Vries Maaike , Smeitink Jan 
Published: June 2006

SummarySecondary deterioration of mitochondrial function has been reported in patients with anorexia and cancer‐related malnutrition. Inadequate nutrition, failure to thrive and feeding problems are also common symptoms in children with primary oxidative phosphorylation defects. As a standard intervention protocol we advise an age‐appropriate diet and energy intake in our patients diagnosed with a mitochondrial dysfunction. By comparing the results of the first and the second samples from a group of children who underwent repeated muscle biopsies, we observed biochemical improvement in the mitochondrial function in 7 out of 10 patients following dietary advice and intervention. We suggest evaluating the nutritional state by interpretation of the skeletal muscle biochemistry in patients with a suspected oxidative phosphorylation defect. Since an insufficient dietary intake could play a role in secondary mitochondrial dysfunction, nutritional intervention should be performed prior to the biopsy. On the other hand, our data suggest that optimizing the nutritional and energy intake might also improve the utilization of the residual mitochondrial energy‐generating capacity in patients with primary oxidative phosphorylation defects.
Decreased μ‐opioid receptor signalling and a reduction in calcium current density in sensory neurons from chronically morphine‐treated mice
Authors: Johnson Emma E , Chieng Billy , Napier Ian , Connor Mark 
Published: June 2006

Sensory neurons are a major site of opioid analgesic action, but the effect of chronic morphine treatment (CMT) on μ‐opioid receptor function in these cells is unknown. We examined μ‐opioid receptor modulation of calcium channel currents (ICa) in small trigeminal ganglion (TG) neurons from mice chronically treated with morphine and measured changes in μ‐opioid receptor mRNA levels in whole TG.
Mice were injected subcutaneously with 300 mg kg−1 of morphine base in a slow release emulsion three times over 5 days, or with emulsion alone (vehicles). CMT mice had a significantly reduced response to the acute antinociceptive effects of 30 mg kg−1 morphine compared with controls (P=0.035).
Morphine inhibited ICa in neurons from CMT (EC50 300 nM) and vehicle (EC50 320 nM) mice with similar potency, but morphine's maximum effect was reduced from 36% inhibition in vehicle to 17% in CMT (P<0.05). Similar results were observed for the selective μ‐opioid agonist Tyr‐D‐Ala‐Gly‐N‐Me‐Phe‐Gly‐ol enkephalin (DAMGO). Inhibition of ICa by the GABAB agonist baclofen was unaffected by CMT.
In neurons from CMT mice, there were significant reductions in P/Q‐type (P=0.007) and L‐type (P=0.002) ICa density.
μ‐Opioid receptor mRNA levels were not altered by CMT.
These data demonstrate that CMT produces a significant reduction of the effectiveness of μ‐opioid agonists to inhibit ICa in TG sensory neurons, accompanied by a reduction in ICa density. Thus, adaptations in sensory neurons may mediate some of the tolerance to the antinociceptive effects of morphine that develop during systemic administration.

British Journal of Pharmacology (2006) 148, 947–955. doi:10.1038/sj.bjp.0706820