bluuebunny/crossref_metadata_2025_split huggingface dataset:
CD8 exerts differential effects on the deployment of cytotoxic T lymphocyte effector functions
Authors: Laugel Bruno , Price David A. , Milicic Anita , Sewell Andrew K. 
Published: March 2007

AbstractCytotoxic T lymphocytes (CTL) are equipped with a range of effector functions that contribute both to the control of intracellular pathogens and dysregulated cellular proliferation and to the development of certain immunopathologies such as autoimmune disease. Qualitative analyses of various CTL responses have revealed substantial heterogeneity in the diversity of functions that are mobilized in response to antigen. Here, we studied the influence of the CD8 co‐receptor, which is known to enhance antigen recognition by CTL, on the secretion of eight different cytokines and chemokines by human CTL clones using flow cytometric bead array. Our results show that abrogation of MHC class I/CD8 interactions exerts a differential influence on the distinct individual effector functions that are elicited in response to agonist ligands. The magnitude of this co‐receptor blockade inhibitory effect was clearly related to the hierarchy of cytokine secretion in terms of activation threshold because those functions requiring the highest amounts of antigen were most affected. Thus, modulation of CD8 activity can effectively tune not only the sensitivity but also the qualitative profile of CTL responses.
Fcα receptor I activation induces leukocyte recruitment and promotes aggravation of glomerulonephritis through the FcRγ adaptor
Authors: Kanamaru Yutaka , Arcos‐Fajardo Michelle , Moura Ivan C. , Tsuge Toshinao , Cohen Hélène , Essig Marie , Vrtovsnik François , Loirat Chantal , Peuchmaur Michel , Beaudoin Lucie , Launay Pierre , Lehuen Agnès , Blank Ulrich , Monteiro Renato C. 
Published: March 2007

AbstractMyeloid cells bear Fc receptors (FcR) that mediate inflammatory signaling through the ITAM‐containing FcRγ adaptor. They express FcRγ‐associated FcαRI, which modulate either activating or inhibitory signaling depending on the type of ligand interaction. The role of FcαRIγ in disease progression remains unknown, notably in IgA nephropathy (IgAN), one of major causes of end‐stage renal disease, in which large amounts of circulating IgA‐immune complexes (IC) may mediate receptor activation. To analyze the involvement of FcαRI activation in glomerulonephritis (GN), we generated Tg mice expressing a mutated, signaling‐incompetent, human FcαRIR209L that cannot associate with FcRγ. Like FcαRIwt‐Tg mice, they developed mesangial IgA deposits but not macrophage infiltration. FcαRI activation in FcαRIwt, but not in FcαRIR209L, Tg mice resulted in marked inflammation with severe proteinuria and leukocyte infiltration in spontaneous IgAN or anti‐glomerular basement membrane Ab‐induced GN models. Receptor triggering of syngenically transferred FcαRIwt Tg macrophages into non‐Tg animals induced their recruitment into injured kidneys during GN development. FcαRIwt cross‐linking on macrophages activated MAP kinases and production of TNF‐α and MCP‐1. Moreover, IgA‐IC from IgAN patients activated FcαRI and induced TNF‐α production. Thus, FcαRI activation mediates GN progression by initiating a cytokine/chemokine cascade that promotes leukocyte recruitment and kidney damage.
New insights into the subversion of the chemokine system by poxviruses
Authors: Alcami Antonio 
Published: March 2007

AbstractViruses encode immune evasion mechanisms to survive in the immunocompetent host. Chemokines mediate the migration of immune cells and their critical role in immunity is emphasized by the numerous virus‐encoded strategies to modulate their activity. Evidence published in this issue of the European Journal of Immunology uncovers novel mechanisms encoded by vaccinia virus to inhibit the chemokine‐mediated migration of DC, an important event in the initiation of the immune response to viral infections.See accompanying article: http://dx.doi.org/10.1002/eji.200636230
Insight Into the Intermolecular Factors Responsible for theZ,ZConfiguration of Ar–X–N=S=N–X–Ar (X = S, Se) Derivatives in the Solid State
Authors: Tersago Karla , Bagryanskaya Irina Yu. , Gatilov Yuri V. , Gromilov Sergey A. , Makarov Alexander Yu. , Mandado Marcos , Van Alsenoy Christian , Zibarev Andrey V. , Blockhuys Frank 
Published: March 2007

AbstractThe molecular and crystal structures of three new derivatives of Ph–S–N=S=N–S–Ph (1), with 2,4,6‐(tert‐C4H9)3C6H2(4), C6F5(5) and 4‐CF3C6F4(6) as peripheral rings, respectively, and one new derivative of Ph–Se–N=S=N–Se–Ph (2), with C6F5(7) as peripheral rings, are reported and discussed in connection with those of the two parent structures1and2and those of the previously studied derivative of1containing 4‐ClC6H4(3) as peripheral rings. For these seven compounds theZ,Zconfiguration is the only one of the three theoretically possible configurations observed in the solid state and this configurational preference can not be explained by intramolecular stereoelectronic effects. Calculation of the packing energies and densities for the six most common space groups revealed that the crystal packing of the parent structure1in theZ,Zconfiguration has a systematic preference over the corresponding packing of1in theZ,Econfiguration by 0.3–4.9 kJ mol–1. As a result, packing forces are most likely responsible for the dominance of theZ,Zconfiguration of the title compounds in the crystal.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
An Unusual Carbonyl Chemical Shift in a Carbonylhexairidium Cluster: A Combined Solid‐State NMR and DFT Approach
Authors: Chierotti Michele R. , Garlaschelli Luigi , Gobetto Roberto , Nervi Carlo , Peli Giulia , Sironi Annalisa , Della Pergola Roberto 
Published: March 2007

AbstractThe 13C NMR spectrum of TMBA2[Ir6(CO)15] [TMBA =(CH3)3N(CH2C6H5)] shows, at low temperatures, an unprecedented μ2‐bridging carbonyl low‐frequency shift, with the resonances of the terminal μ1‐carbonyl ligands placed at higher frequencies. The chemical shift tensors and the shielding anisotropies of the carbonyl ligands, obtained from solid‐state NMR analysis, allow us to determine the nature of the M–CO interaction. The results have been compared with the 13C MAS data of Ir6(CO)16 where μ3‐CO ligands are present. Further evidence for the assignment and for the peculiar chemical shift value of bridging carbonyl ligands in TMBA2[Ir6(CO)15] has been obtained by the DFT calculation of the NMR parameters. The scalar and spin‐orbit (SO) relativistic two‐component zero‐order regular approximation (ZORA) methods were employed in the geometry optimization and NMR chemical shift calculations, respectively. The large SO contribution (δ = 26.6 ppm) to the μ2‐bridging CO ligand 13C chemical shifts accounts for the position of the experimentally observed resonance.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
The Relationship Between 27Al Quadrupolar Parameters and AlF63– Octahedron Connectivity in Crystalline and Glassy Fluoroaluminates
Authors: Body Monique , Legein Christophe , Buzaré Jean‐Yves , Silly Gilles 
Published: March 2007

Abstract27Al SATRAS and MQ‐MAS spectra were recorded for eight crystalline compounds, from the CaF2–AlF3 and BaF2–AlF3 binary and BaF2–CaF2–AlF3 ternary systems, and four glass compositions with different CaF2/BaF2/AlF3 contents. For the crystalline phases, the reconstruction of the spectra leads to the precise determination of the NMR parameters. For the glassy phases, the 27Al SATRAS spectra have been reconstructed using quadrupolar parameter distributions. The main finding of this study is the dependence of the quadrupolar frequency on the type of AlF63– octahedron connectivity. For crystalline phases the experimental νQ values range between 75 kHz and 510 kHz for structures built up from isolated octahedra, and are between 560 kHz and 1250 kHz for structures built up from isolated chains of cis‐connected octahedra, and are between 1530 kHz and 1580 kHz for structures built up from isolated chains of trans‐connected octahedra. In the glassy phases the maximum of the quadrupolar frequency distribution shifts toward larger values and its width increases with increasing AlF3 content, and subsequently with the number of connected octahedra. The range of the νQ values seems to indicate that when the octahedra are connected, cis connections occur most frequently. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Bis(phenylethylamide) Derivatives of Gd‐DTPA as Potential Receptor‐Specific MRI Contrast Agents
Authors: Laurent Sophie , Parac‐Vogt Tatjana N. , Kimpe Kristof , Thirifays Coralie , Binnemans Koen , Muller Robert N. , Vander Elst Luce 
Published: March 2007

AbstractDTPA‐bis(amide) derivatives bearing phenyl, phenol or catechol groups that mimic side chains of naturally occurring amino acids, such as phenylalanine, tyrosine or dopamine, were synthesized and characterized by elemental analysis, electrospray mass spectrometry, NMR spectroscopy and IR spectroscopy. The gadolinium(III) complexes of the ligands DTPA‐bis(tyramide) [DTPA‐(TA)2], DTPA‐bis(3‐hydroxytyramide) [DTPA‐(HTA)2] and DTPA‐bis(phenylalanine ethyl ester) [DTPA‐(PAE)2], were prepared and then studied in vitro by 17O NMR spectroscopy and by nuclear magnetic relaxation dispersion (NMRD) measurements. The residence time of the coordinated water in gadolinium(III) complexes was obtained from 17O NMR relaxometric T2 measurements. At 310 K, the following τM values were obtained: Gd‐DTPA‐(TA)2 582 ns, Gd‐DTPA‐(HTA)2 372 ns and Gd‐DTPA‐(PAE)2 809 ns. As shown by the analysis of the proton NMRD profiles, the larger proton relaxivities of the gadolinium(III) complexes at 310 K relative to that of the parent Gd‐DTPA complex are mainly because of the increase in the rotationalcorrelation time. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Succinimidyl Carbamate Derivatives from N‐Protected α‐Amino Acids and Dipeptides―Synthesis of Ureidopeptides and Oligourea/Peptide Hybrids
Authors: Fischer Lucile , Semetey Vincent , Lozano Jose‐Manuel , Schaffner Arnaud‐Pierre , Briand Jean‐Paul , Didierjean Claude , Guichard Gilles 
Published: March 2007

AbstractThe preparation of succinimidyl (1‐{[(alkyloxy)carbonyl]amino}‐1‐X‐methyl)carbamates (4) and succinimidyl [1‐(acylamino)‐1‐X‐methyl] carbamates (5) from a variety ofN‐Boc‐, ‐Z‐ or ‐Fmoc‐protected α‐amino acids and dipeptides as well as the carbamate structural characterization are described. We have previously shown that succinimidyl carbamates 5, derived from N‐Boc dipeptides, can serve as direct precursors of 1,3,5‐triazepan‐2,6‐diones, a novel class of conformationally constrained dipeptide mimetics. Herein, we have evaluated the use of these building blocks for the synthesis of ureido‐peptides (in solution and on solid support), peptidyl hydantoins, oligoureas and some oligo(urea/amide) hybrids. Conformational investigations by NMR of ureidotripeptide 6i and pentamer 10, consisting of alternating amides and ureas, suggested that folded conformations (i.e. a urea turn) characterized by a cis,trans (E,Z) geometry of the urea linkage are populated in both [D5]pyridine and [D6]DMSO solutions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Vinylic Halogenation in 4‐Alkylidenazetidin‐2‐ones
Authors: Cainelli Gianfranco , Galletti Paola , Giacomini Daria , Licciulli Sebastiano , Quintavalla Arianna 
Published: March 2007

AbstractThe synthesis of a new family of halogenated β‐lactams by oxidative substitution of vinylic hydrogen in conjugated double bonds of 4‐alkylidenazetidinones is reported. Optimised procedures give good to excellent yields of chloro, bromo, iodo and nitro derivatives. A mechanism to explain the direct vinylic substitution is proposed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Envelopes of maximum seismic response for a partially symmetric single storey building model
Authors: Dempsey K. M. , Irvine H. M. 
Published: March 2007

AbstractAn analysis is made of the coupled lateral‐torsional response of a partially symmetric single‐storey building model to horizontal translatory earthquake excitation. Interest centres on the evaluation of realistic estimates for two equivalent static actions (a shear and a torque) which account for the worst dynamic consequences of torsional unbalance. The results substantiate the findings of previous investigations which have given rise to the belief that strong modal coupling and severely coupled lateral and torsional responses are possible even in nominally symmetric buildings. The response of the model is assumed to be linearly elastic and viscously damped.In a preliminary analysis the equations of motion are solved using the modal analysis technique and the conditions necessary for full modal coupling are ascertained.Then by employing the design spectrum concept, together with suitably conservative procedures for combining the modal maxima, dimensionless forms of the equivalent static actions are evaluated as functions of two independent parameters. The final results are furnished by modified square root of the sum of the squares (SRSS) combination functions which take account of the spacing between the translational and torsional frequencies. Examples at the end of the paper illustrate the practical significance of the work.
Simulation of three‐dimensional strong ground motions along principal axes, San Fernando earthquake
Authors: Kubo Tetsuo , Penzien Joseph 
Published: March 2007

AbstractPower spectral density which describes frequency content is considered one of the most significant properties to be taken into account when generating ground motions through the use of stochastic processes. Using a smoothed and normalized Fourier amplitude spectrum, frequency content for components of motion along a set of principal axes is estimated. Fourier amplitude spectra obtained by this moving‐window technique are presented which show the time dependency of frequency content for motions produced by the San Fernando earthquake of 9 February 1971.A mathematical model to simulate ground motion processes is proposed for which both the intensity and frequency content are non‐stationary. Using this mathematical model with parameter characteristics along principal axes similar to those of the motions recorded during the San Fernando earthquake, three‐dimensional ground motions are synthetically generated. The properties of the simulated motions show general characteristics similar to the characteristics observed in real accelerograms. The suggested model is considered adequate for engineering purposes.
The inelastic vibration absorber subjected to earthquake ground motions
Authors: Jagadish K. S. , Prasad B. K. Raghu , Rao P. Vasudeva 
Published: March 2007

AbstractTwo storey bilinear hysteretic structures have been studied with a view to exploring the possibility of using the dynamic vibration absorber concept in earthquake‐resistant design. The response of the lower storey has been optimized for the Taft 1952, S69°E accelerogram with reference to parameters such as frequency ratio, yield strength ratio and mass ratio. The influence of viscous damping has also been examined.
Response using the Rayleigh‐Ritz method
Authors: Warburton G. B. 
Published: March 2007

AbstractAs an example of the extension of the Rayleigh‐Ritz method to response calculations, analysis is outlined for a damped rectangular plate. For harmonic excitation amplitudes of displacement and bending moment are compared with values from a modal solution from the plate equation. In general, the Rayleigh‐Ritz method predicts displacements of acceptable accuracy, but for a given number of terms accuracy is less for response calculations than for the determination of comparable eigenvalues. Bending moments may converge slowly to the true values, as the number of terms in the assumed series is increased.
Axisymmetric transients in shells of revolution
Authors: Thambiratnam D. P. , Shah A. H. , Cohen H. 
Published: March 2007

AbstractThe propagation of axisymmetric transients in shells of revolution subjected to impulsive boundary loads is treated in this paper. Consideration is restricted to linear, elastic, isotropic, homogeneous shells of revolution with straight line generators. The analysis is based on the concept of a wave as a carrier of discontinuities in the field variable and its derivatives. These discontinuities are determined from a set of recurrence relations which are in turn generated by the use of asymptotic series solutions to the equations of motion. A numerical superposition technique which enables the calculation of long time response is developed. Several numerical examples are presented in order to illustrate the method.
Evaluation of simulated ground motions for predicting elastic response of long period structures and inelastic response of structures
Authors: Chopra Anil K. , Lopez Oscar A. 
Published: March 2007

AbstractThe response of linear elastic and non‐linear hysteretic systems having a single degree of freedom to recorded and simulated ground motions is studied. The objective is to evaluate whether the commonly used simulated motions are appropriate for predicting inelastic response of structures and elastic response of long period structures.Eight simulated motions were generated to model properties of horizontal ground motions recorded during four earthquakes. The simulated motions are sample functions of a stationary, Gaussian white noise process, multiplied by a temporal intensity function and passed through a linear single‐degree‐of‐freedom filter. Two versions, corresponding to parabolic and ‘standard’ base line corrections (BLC), of each of the simulated and recorded accelerograms were considered.The following general conclusions are deduced. Simulated ground motions should be subjected to the standard BLC, because it results in more reliable ground velocities and displacements, which in turn would lead to more reliable predictions of response of long period structures. Furthermore, the spectral density of the underlying random process, from which the simulated motions are obtained, should be modified to be more representative of the frequency content of recorded motions, especially in the low frequency range. Such an improved model can be expected to lead to better agreement, over a broad range of periods, in the average response spectra of simulated and recorded motions, for elastic as well as inelastic systems.
On the accuracy of mode superposition analysis in structural dynamics
Authors: Hansteen Ole Edvard , Bell Kolbein 
Published: March 2007

AbstractIt is pointed out that the number of modes which should be included in a mode superposition dynamic response analysis depends on both the frequency content and the distribution of the loading. If the loading frequency is low the effect of the higher modes can be approximated by a static analysis. A technique is described for calculating this static contribution from the higher modes; the total response is then represented by the sum of the lower mode dynamic response and the higher mode static effects. The effectiveness of the procedure is demonstrated by a numerical example.
On the significance of phase content in earthquake ground motions
Authors: Ohsaki Y. 
Published: March 2007

AbstractA number of problems relating to characteristics of harmonic phase angles contained in earthquake ground motions are discussed, which have been mostly overlooked in the past in contrast with the importance placed on harmonic amplitudes. Particularly, the significance of the concept of phase differences in certain properties of earthquake ground motions is emphasized. A few applications of this new concept to earthquake engineering problems are illustrated as well.
Generation of artificial strong motion accelerograms
Authors: Wong H. L. , Trifunac M. D. 
Published: March 2007

AbstractA method for generating synthetic strong motion accelerograms for use in engineering design is presented. This method utilizes the model proposed by Trifunac in 197127 in conjunction with the recent empirical scaling functions for characterization of amplitudes and duration of strong shaking in terms of (i) earthquake magnitude, M, and epicentral distance, R, or (ii) Modified Mercalli Intensity (MMI) at the recording station. The method also enables one to consider the desired levels of confidence that the synthetic motion will not be exceeded, direction of ground motion (horizontal or vertical) and the dispersive properties of geologic environment beneath and surrounding the station. The principal features of this approach are that the resulting accelerograms have non‐stationary frequency and amplitude characteristics which are in full agreement with known principles of wave propagation through a stratified medium, and that the Fourier amplitudes and the frequency‐dependent duration are scaled in accordance with known trends as in recorded accelerograms.
Use of fault displacements in the evaluation of seismic risk
Authors: Kaul Maharaj K. 
Published: March 2007

AbstractThe need for a probabilistic description of earthquake magnitudes and their epicentres, specifically their joint probability density function, arises in the quantitative assessment of seismic risk. For line sources, this description has generally been assumed to be of a specific form dictated primarily by the unavailability of relevant statistical data. The need for such simplification can, however, be eliminated if the available statistical data are supplemented by the knowledge of the accumulated displacements on the fault, thereby leading to an improved estimate of the required probability density function. A procedure to obtain such an improved estimate and simultaneously the mean occurrence rate of earthquakes originating from the fault is developed in this paper. The use of these refined inputs in the seismic risk evaluation is described. Numerical examples are presented for illustration.
Dynamic fluid effects in liquid‐filled flexible cylindrical tanks
Authors: Fischer D. 
Published: March 2007

AbstractThe velocity potential of a compressible fluid is found by Galerkin's method. Free surface displacements and a flexible tank wall are assumed. Explicit expressions for the impulsive mass, the impulsive moment and the overturning moment are derived for wave number m = 1. In the case of m ≥ 1 the dynamic effect of the fluid is represented by a fictitious apparent mass in explicit form.
Response of sliding structures to earthquake support motion
Authors: Mostaghel N. , Tanbakuchi J. 
Published: March 2007

AbstractTo study the effectiveness of sliding supports in isolating structures from damaging earthquake ground motions, a mathematical model of a single degree of freedom structure supported on a sliding foundation and subjected to the N‐S component of the El Centro 1940 earthquake is considered. Spectra for absolute accelerations, relative displacements, relative‐to‐ground displacements, sliding displacements and residual sliding displacements are evaluated for three mass ratios, four coefficients of friction and a damping of 5 per cent critical. It is observed that, for structures with periods less than 1‐8 s, for the coefficients of friction considered, the suprema of relative‐to‐ground displacements, sliding displacements and residual sliding displacements are only of the order of 1–25 times the peak ground displacement. To study the response sensitivities, the spectra for absolute acceleration and sliding displacement of the 1949 Olympia earthquake (S86E component) are also presented. It is concluded that sliding supports can be quite effective in isolating structures from support excitations.