bluuebunny/crossref_metadata_2025 huggingface dataset:
A LIGHT AND ELECTRON MICROSCOPIC STUDY OF OXYTOCIN‐CONTAINING NEURONS IN THE PARA‐VENTRICULAR NUCLEUS OF THE RAT
Authors: Loesch Andrzej
Published: August 2007

Oxytocin‐containing neurons and axon terminals contacting the neurons of the rat paraventricular nucleus were investigated by the peroxidase‐antiperoxidase technique for light and electron microscopy. At the light microscopic level the reaction product was seen to fill the somata, dendrites and axons of the neurons. At the ultrastructural level the immunoprecipitate was localized on cytoplasm (including ergastoplasm) and neurosecretory granules (NSG) of the somata; microtubules, ergastoplasm and NSG of the dendrites; and NSG of the axons. Axon terminals synapsing on the surface of the labelled somata and dendrites were exclusively unlabelled. The somata and dendrites were observed to receive both asymmetrical (Gray's type I) and symmetrical (Gray's type II) synapses with clear, mostly spherical and flattened vesicles, respectively. Frequently, pleomorphic vesicles and a few dense‐core vesicles occurred in both types of synapses. There also were present some unlabelled bridge‐like axon terminals making ‘double’ synapses either on two labelled dendritic processes or on one unlabelled and one labelled dendrite. The present findings demonstrate that the somata and dendrites of the oxytocin‐containing neurons receive diverse innervation. At the same time there was no evidence in this study for synaptic input to the labelled axons of the neurons.
Interleukin-1 Receptor Antagonist Penetrates Human Brain at Experimentally Therapeutic Concentrations
Authors: Clark Simon R , McMahon Catherine J , Gueorguieva Iva , Rowland Malcolm , Scarth Sylvia , Georgiou Rachel , Tyrrell Pippa J , Hopkins Stephen J , Rothwell Nancy J
Published: August 2007

The proinflammatory cytokine interleukin (IL)-1 mediates several forms of experimentally induced acute brain injury and has been implicated in chronic neurodegenerative disorders. The IL-1 receptor antagonist, IL-1RA, protects rodents against ischaemic brain injury, but its molecular mass (17 kDa) potentially limits the brain penetration of peripherally administered IL-1RA. We therefore sought to identify whether therapeutically effective concentrations of IL-1RA in the rat were also achieved in brain of patients with subarachnoid haemorrhage (SAH), using a peripheral administration regime that had proved to be safe and reduce peripheral inflammation in patients after stroke. An intravenous bolus of IL-1RA, followed by infusion, was administered to rats after induction of focal cerebral ischaemia. The effects of IL-1RA on brain ischaemia and the concentrations achieved in cerebrospinal fluid (CSF), were determined. Interleukin-1 receptor antagonist was similarly administered to patients with SAH, and CSF was sampled via external ventricular drains. In rats, IL-1RA significantly reduced brain injury induced by focal cerebral ischaemia. The plasma IL-1RA concentrations reached 12±2 μg/mL by 30 mins, and CSF concentrations were maintained between 91 and 232 ng/mL between 1 and 24 h of infusion. In patients with SAH, IL-1RA reached a steady-state plasma concentration of 22 ± 4 μg/mL by 15 mins, and CSF concentrations were maintained at 78 to 558 ng/mL between 1 and 24 h. Intravenous delivery of IL-1RA leads to CSF concentrations in patients comparable to those that are neuroprotective in rats, and might therefore be of therapeutic benefit.
Combined effects of electron partial thermalization and secondary emission in Hall thruster discharges
Authors: Ahedo E. , De Pablo V.
Published: August 2007

A model of the plasma interaction with the ceramic walls of a Hall thruster chamber is presented that takes into account partial thermalization of the electron distribution function. A model of secondary electron emission with both elastically reflected and true-secondary electrons is considered. The plasma response is found to differ substantially from low to high thermalization. The different roles of the bulk and emitted populations of electrons are discussed. Plasma fluxes to the wall are independent of the thermalization level except in the very-low thermalization limit, when the tail of the distribution function of bulk electrons is highly depleted. To the contrary, energy losses to the walls and the sheath charge saturation limit depend strongly on the level of thermalization. Elastically reflected electrons affect significantly the plasma response by modifying the fluxes of primary and secondary electrons at the walls. Emphasis is put on obtaining analytical expressions for main plasma magnitudes, which can be implemented in two-dimensional models of the whole plasma discharge.
Influence of thermostats and carrier gas on simulations of nucleation
Authors: Wedekind Jan , Reguera David , Strey Reinhard
Published: August 2007

We investigate the influence of carrier gas and thermostat on molecular dynamics (MD) simulations of nucleation. The task of keeping the temperature constant in MD simulations is not trivial and an inefficient thermalization may have a strong influence on the results. Different thermostating mechanisms have been proposed and used in the past. In particular, we analyze the efficiency of velocity rescaling, Nosé-Hoover, and a carrier gas (mimicking the experimental situation) by extensive MD simulations. Since nucleation is highly sensitive to temperature, one would expect that small variations in temperature might lead to differences in nucleation rates of up to several orders of magnitude. Surprisingly, the results indicate that the choice of the thermostating method in a simulation does not have—at least in the case of Lennard-Jones argon—a very significant influence on the nucleation rate. These findings are interpreted in the context of the classical theory of Feder et al. [Adv. Phys. 15, 111 (1966)] by analyzing the temperature distribution of the nucleating clusters. We find that the distribution of cluster temperatures is non-Gaussian and that subcritically sized clusters are colder while postcritically sized clusters are warmer than the bath temperature. However, the average temperature of all clusters is found to be always higher than the bath temperature.
A kinetic-theory based first order slip boundary condition for gas flow
Authors: Shen Sheng , Chen Gang , Crone Robert M. , Anaya-Dufresne Manuel
Published: August 2007

In this paper, a first-order slip boundary condition is derived using the Chapman-Enskog solution of the Boltzmann equation. In comparison with the existing slip models such as first, second, and 1.5-order slip models, the Poiseuille flow rate predicted by the new slip model shows better agreement with that calculated by the linearized Boltzmann equation. The slip boundary condition is also applied to predict the pressure field in gas lubrication problems.
On gravity currents in stratified ambients
Authors: Birman V. K. , Meiburg E. , Ungarish M.
Published: August 2007

Detailed numerical simulations were conducted of gravity currents released from a lock and propagating at the bottom of a linearly stratified ambient. The objective is to test the predictions of the recent theoretical analysis by Ungarish [M. Ungarish, J. Fluid Mech. 548, 49 (2006)] concerning the dependency of the front velocity (Froude number, Fr) on the stratification parameter (S) and height ratio (a). The functional dependence of the front velocity on S is found to agree with the theoretical results for weak stratification, although the numerically obtained front velocities lie below the predicted values, as a result of viscous effects. Simulations for deeply submerged currents (small a) in strongly stratified ambients (S>0.5) show that the front velocities deviate from the fastest predicted theoretical solution, but fall within the range of the slower solutions found by Ungarish. This observation supports the theoretical prediction concerning (a) the existence of multiple solutions; and (b) the selection of the slowest solution as the front velocity in a nonforced time-dependent flow. The computational results point to the action of internal waves as the cause for the reduced front velocity. The numerical results also confirm the prediction that the thickness ratio of current to ambient is less than one half, and decreases with S.
Effects of hydrophobic surfaces on the drag and lift of a circular cylinder
Authors: You Donghyun , Moin Parviz
Published: August 2007

Effects of hydrophobic surfaces on the drag and lift of a circular cylinder at Reynolds numbers of 300 and 3900 are investigated using numerical simulations. A cylinder of which the entire surface is no-slip, a cylinder of which the entire surface is hydrophobic, and cylinders with alternating circumferential bands of slip and no-slip conditions are considered. The width of the alternating bands ranges from 0.5λz to 2λz, where λz is a spanwise characteristic wavelength in the near wake. At Reynolds number 300, the hydrophobic surface consisting of alternating slip and no-slip bands of width λz is found to be most effective in enhancing wake instability, thereby decreasing the base suction, drag, and rms lift coefficients. At Reynolds number 3900, hydrophobic surface treatments are found to delay flow separation, thereby decreasing the drag and rms lift.
The onset of Soret-driven convection in a binary mixture heated from above
Authors: Kim Min Chan , Choi Chang Kyun , Yeo Jong-Kee
Published: August 2007

The onset of buoyancy-driven convection in an initially quiescent, horizontal fluid layer heated from above is analyzed theoretically. The present system of binary mixtures is a thermally stable one but the Soret diffusion can induce buoyancy-driven motion. With highly unstable density gradients the convective motion sets in during the transient diffusion stage. Here the onset time of convective motion is analyzed by employing the propagation theory. The dimensionless critical time τc and the critical wavenumber ac to mark the onset of convective motion is presented as a function of the Rayleigh number Ra, the Lewis number Le, and the separation ratio ψ. The results show that the onset time decreases with increasing buoyancy force Ra(Le∕ψ)−1 and the predicted ac-values agree well with available experimental data. For the ethanol-water system the predicted critical reduced Rayleigh number rc(=Rac∕1708)=−0.0464 agrees reasonably with existing experimental results of r=−0.1. It is found that the visible motion can be detected from a certain time τ≅43∕4τc.
Mechanics and refractive power optimization of tunable acoustic gradient lenses
Authors: McLeod Euan , Arnold Craig B.
Published: August 2007

Tunable acoustic gradient index (TAG) lenses create tunable multiscale Bessel beams. These lenses are fluid-filled cylindrical cavities within which an acoustic radial standing wave is excited. This standing wave modulates the density, and thereby the refractive index within the lens. Spatial gradients in the refractive index can be used for lensing. A predictive model for the steady-state fluid mechanics behind TAG lenses driven with a sinusoidal voltage signal is presented here. The model covers inviscid and viscous regimes in both the resonant and off-resonant cases. The density fluctuations from the fluidic model are related to refractive index fluctuations. The entire model is then analyzed to determine the optimal values of lens design parameters for greatest lens refractive power. These design parameters include lens length, radius, static refractive index, fluid viscosity, sound speed, and driving frequency and amplitude. It is found that long lenses filled with a fluid of high refractive index and driven with large amplitude signals form the most effective lenses. When dealing with resonant driving conditions, low driving frequencies, smaller lens radii, and fluids with larger sound speeds are optimal. At nonresonant driving conditions, the opposite is true: High driving frequencies, larger radius lenses, and fluids with low sound speeds are beneficial. The ease of tunability of the TAG lens through modifying the driving signal is discussed, as are limitations of the model including cavitation and nonlinearities within the lens.
Electron-induced ferromagnetic ordering of Co-doped ZnO
Authors: Kan Er-Jun , Yuan Lan-Feng , Yang Jinlong
Published: August 2007

The electronic and magnetic properties of Co-doped ZnO are investigated based on the B3LYP hybrid spin-density functional method. The calculated electronic structures obtained from B3LYP agree well with the experimental results. B3LYP predicts that antiferromagnetic (AFM) ordering between the Co ions is favored over ferromagnetic (FM) ordering in intrinsic Co-doped ZnO, and reveals that the FM ordering can be induced by electron doping when the doping level reaches 1 electron per Co ion. These results agree well with the FM ordering observed in highly conductive n-type Zn1−xCoxO films. Charge transfer to the minority-spin d states of Co atoms and the consequent double-exchange interaction are the primary origins of FM ordering. Since Ni has one more electron than Co, we also investigate the electronic and magnetic properties of intrinsic Ni-doped ZnO. Qualitatively different from the local-density-approximation results, B3LYP predicts that Ni-doped ZnO is an insulator and favors AFM ordering.
A defect-free thin film pentacene diode: Interplay between transport and scanning tunneling microscope tip tunneling injection
Authors: Ruppel L. , Birkner A. , Witte G. , Busse C. , Lindner Th. , Paasch G. , Wöll Ch.
Published: August 2007

A diodelike device has been fabricated by organic molecular beam deposition of pentacene on a surface-modified, single-crystalline Au substrate. Using the substrate as the first and the tip of a scanning tunneling microscope (STM) as the second electrode, transport characteristics of this organic semiconductor (OSC) device were investigated. The probed pentacene islands are single crystalline and defect-free and consist of few molecular layers only. The current-voltage characteristics of this device reveal a pronounced asymmetry. For negative polarity, the current characteristics is almost independent of the layer thickness. For positive polarity, the current onset is shifted significantly to larger voltages with increasing layer thickness. Numerical simulations for a two-dimensional model system allow us to identify the injection properties of the STM tip as reasons for this pronounced asymmetry. For negative substrate bias the creation of holes in the valence band occurs by tunneling of electrons to the tip whereas in the opposite case holes have to be transported through the OSC layer from the substrate. Thus, for low positive voltage the hole current limits the device current. Once the resulting voltage drop between layer and tip becomes larger than the barrier for electron injection, direct tunneling of electrons into the pentacene conduction band becomes possible and n conduction begins to dominate.
Hydrogenic-donor impurity states in coupled quantum disks in the presence of a magnetic field
Authors: Liu Li-Zhe , Liu Jian-Jun
Published: August 2007

We report the binding energies of a hydrogenic-donor impurity in a cylindrically symmetric GaAs∕Ga1−xAlxAs-coupled quantum disk in the presence of a uniform magnetic field for different disk and barrier thicknesses, disk radii, and donor ion positions within the disk. The magnetic field is assumed to be applied parallel to the disk axis. The calculations were performed using a variational procedure for finite-confinement potentials within the effective-mass approximation. The calculated results show that the binding energy is dependent on the interplay of the spatial confinement and magnetic-field confinement: A high magnetic field significantly enhances the binding energy in the case of weak spatial confinement. The binding energy of a hydrogenic-donor impurity in two coupled quantum disks is found to be smaller than that in a corresponding single quantum disk, due to the coupling effect between the disks. In the limits of coupled quantum wells, the results we obtain are in good agreement with those previously obtained for the case in which the donor ion is located at the center of the quantum disk.
Mass detection using capacitive resonant silicon resonator employing LC resonant circuit technique
Authors: Kim Sang-Jin , Ono Takahito , Esashi Masayoshi
Published: August 2007

Capacitive resonant mass sensing using a single-crystalline silicon resonator with an electrical LC oscillator was demonstrated in ambient atmosphere. Using capacitive detection method, the detectable minimum mass of 1×10−14g was obtained in the self-oscillation of cantilever with a thickness of 250nm. The noise amplitude of the sensor output corresponds to a vibration amplitude of 0.05nm∕(Hz)0.5 in the frequency domain compared with the actuation signal, which is equivalent to the detectable minimum capacitance variation of 2.4×10−21F. Using the capacitive detection method, mass/stress induced resonance frequency shift due to the adsorption of ethanol and moist vapor in a pure N2 gas as a carrier is successfully demonstrated. These results show the high potential of capacitive silicon resonator for high mass/stress-sensitive sensor.
Electrochemically induced crystallization in lead fluoroborate glasses below the glass transition temperature
Authors: De Souza José Ezequiel , M’Peko Jean-Claude , Hernandes Antonio Carlos
Published: August 2007

Lead fluoroborate (BO1.5–PbO–PbF2) glasses were prepared by melt quenching and studied here in terms of (micro)structural and electrical properties. The results show that electrochemically induced surface crystallization may also occur below the glass transition temperature. As previously proposed elsewhere and shown here, occurrence of this phenomenon arose from a field-induced redox reaction at the electrodes, followed by crystallite nucleation. Once nucleated, growth of β-PbF2 crystallites, with the indication of incorporating reduced lead ions (Pb+), was both (micro)structurally and electrically detectable and was analyzed. In particular, the authors introduce a procedure combining impedance spectroscopy and polarization/depolarization techniques to also monitor this phenomenon.
Structure, magnetic property, and spin polarization of Co2FeAlxSi1−x Heusler alloys
Authors: Nakatani T. M. , Rajanikanth A. , Gercsi Z. , Takahashi Y. K. , Inomata K. , Hono K.
Published: August 2007

We report the spin polarization of Co2FeAlxSi1−x (x=0.0, 0.3, 0.5, 0.7) bulk alloys measured by the point contact Andreev reflection method. All the Co2FeAlxSi1−x alloys had an L21 structure along with A2- and B2-type disorder. Several off-stoichiometric alloys (CoxFeyAl0.5Si0.5) were prepared to understand the effect of the compositional deviation from the stoichiometry on the spin polarization. By substituting Al for Si, the spin polarization changed from 0.57±0.01 for x=0.0 to a maximum value of 0.60±0.01 for x=0.5. The off-stoichiometric alloys had spin polarizations of 0.57−0.60±0.01. Ab initio calculations were performed to interpret the effect of Al addition as well as the effect of disorder on the magnetic properties and on the electronic structure.
Central peak and acoustic anomalies of the relaxor ferroelectric lead magnesium niobate-lead titanate single crystal studied by the micro-Brillouin scattering
Authors: Shabbir Ghulam , Kojima Seiji
Published: August 2007

Quasielastic central peak and acoustic anomalies in a [001] lead magnesium niobate-lead titanate single crystal have been investigated by the high-resolution micro-Brillouin scattering. Two acoustic anomalies were observed at temperatures, TC-T∼415K and TT-R∼348K. The damping showed a significant dispersion at T∼550K, associated with the enhanced dynamics of local strain fields created by the polar microregions. The temperature evolution of the quasielastic central peak exhibited anomalies in the overall intensity and relaxation time that were associated with the line shape interferences of the central peak and the acoustic mode.
Phase transformation and freestanding nanoparticles formation in lead zirconate titanate derived by sol-gel
Authors: Faheem Yasir , Joya Khurram Saleem
Published: August 2007

Generation of the freestanding lead zirconate titanate (PZT) nanoparticles and their phase transformation behavior is investigated in this research. PZT sol-gel precursor was dried at 250°C and partially calcined at 450°C for 30min to decompose organics and bring down the free energy barrier for perovskite crystallization. Annealed at 550–600°C, sol-gel PZT powder exhibited freestanding nanocrystalline morphology. The electron diffraction pattern obtained from nanoparticles confirmed their crystallinity and perovskite phase formation. The structural characteristics were evaluated by transmission electron microscope and x-ray diffraction techniques. The average PZT nanoparticle size of 20nm was observed by transmission electron microscope and Scherrer’s method.
First-principles study of magnetic properties in V-doped ZnO
Authors: Wang Qian , Sun Qiang , Jena Puru , Hu Zheng , Note R. , Kawazoe Y.
Published: August 2007

A comprehensive theoretical study of electronic and magnetic properties of V-doped ZnO in bulk as well as (112¯0) thin films has been performed using density functional theory. Vanadium atoms substituted at Zn sites show very little selectivity of site occupancy. More importantly, different geometries with ferromagnetic, ferrimagnetic, and antiferromagnetic configurations are found to be energetically nearly degenerate both in Zn1−xVxO bulk and subsurface layers of the thin film. On the other hand, V atoms couple ferromagnetically when they occupy surface sites of the thin film. The diverse magnetic behaviors in V-doped ZnO account for the many reported conflicting experimental results.
Drift and diffusion of spins generated by the spin Hall effect
Authors: Stern N. P. , Steuerman D. W. , Mack S. , Gossard A. C. , Awschalom D. D.
Published: August 2007

Electrically generated spin accumulation due to the spin Hall effect is imaged in n-GaAs channels using Kerr rotation microscopy, focusing on its spatial distribution and time-averaged behavior in a magnetic field. Spatially resolved imaging reveals that spin accumulation observed in transverse arms develops due to the longitudinal drift of spin polarization produced at the sample boundaries. One- and two-dimensional drift-diffusion modeling is used to explain these features, providing a more complete understanding of observations of spin accumulation and the spin Hall effect.
Ultratransparent glass ceramics: The structure factor and the quenching of the Rayleigh scattering
Authors: Mattarelli M. , Montagna M. , Verrocchio P.
Published: August 2007

Glass ceramics with nanocrystals present a transparency higher than that expected from the theory of Rayleigh scattering. This ultratransparency is attributed to the spatial correlation of the nanoparticles. The structure factor is calculated for a simple model system, the random sequential addition of equal spheres, at different volume filling factor. The spatial correlation given by the constraint that particles cannot superimpose produces a diffraction peak with a low S(q) in its low-q tail, which is relevant for light scattering. The physical mechanism producing high transparency in glass ceramics is demonstrated to be the low density fluctuation in the number of scatterers.
Self-assembled monolayers for reduced temperature direct metal thermocompression bonding
Authors: Ang X. F. , Li F. Y. , Tan W. L. , Chen Z. , Wong C. C. , Wei J.
Published: August 2007

A reduction in the bonding temperature required for direct gold-gold (Au–Au) thermocompression bonding is observed by coating a monolayer of dodecanethiol on gold surfaces prior to bonding. The results show that Au–Au bonded joints of 26.9g per bump strength can be achieved at a temperature as low as 160°C. The temperature drop becomes more apparent when both coated and blank gold samples are exposed in air over some time before bonding. The authors propose that self-assembled monolayers passivate metal surface by obviating the adsorption of surface contaminants, in particular, carbon and oxygen but get desorbed just before bonding takes place.
Competition between two four-wave mixing channels via atomic coherence
Authors: Zhang Yanpeng , Anderson Blake , Brown Andy W. , Xiao Min
Published: August 2007

Two four-wave-mixing (FWM) processes can coexist in a four-level Y-type atomic system with carefully arranged coupling laser beams. The generated two FWM signal beams fall into two simultaneously opened dual electromagnetically induced transparency (EIT) windows, which can be tuned to overlap or separate by various frequency detunings. The authors report our experimental observation of competing FWM processes, especially mutual suppression of the two FWM signals when the two EIT windows merge in frequency. Controlling FWM processes can have important applications in wavelength conversion for optical communication.
Unusual resistivity hysteresis in a bulk magnetoresistive ferromagnetic/ferrimagnetic composite (La0.7Ca0.3MnO3∕Mn3O4): Role of demagnetization effects
Authors: Vertruyen B. , Cloots R. , Ausloos M. , Fagnard J.-F. , Vanderbemden Ph.
Published: August 2007

The authors report an intriguing resistivity versus magnetic field dependence in polycrystalline composite samples containing a magnetoresistive manganite (ferromagnetic/conducting La0.7Ca0.3MnO3) and a magnetic manganese oxide (ferrimagnetic/insulating Mn3O4). At 10K, when the magnetic field is scanned from positive to negative values, the resistance peak occurs at positive magnetic field, instead of zero or negative field as usually observed in polycrystalline manganite samples. The position of the resistance peak agrees well with the cancellation of the internal magnetic field, suggesting that the demagnetization effects are responsible for this behavior.
Modeling the mechanisms driving ac electro-osmotic flow on planar microelectrodes
Authors: Morin Fabrice Olivier , Gillot Frédéric , Fujita Hiroyuki
Published: August 2007

The authors introduce an electrical model of the electrode-electrolyte interface and use it to discuss the mechanisms responsible for the generation of ac electro-osmotic flows at the surface of planar electrodes. They propose that such flows are generated by two distinct mechanisms: nonuniform diffusion of ionic species from the bulk to the electrode surface and inhomogeneous electrochemical transfer across the electrode surface. They then proceed to explain experimental observations in two situations where one mechanism dominates over the other, in each case validating the inclusion of specific components in their model.
End-Capped Terfluorene Derivatives: Synthesis and Structure - Functional Property Relationships
Authors: Xiong Mo Jun , Li Zhong Hui , Wong Man Shing
Published: August 2007

A series of monodisperse symmetric terfluorenes end-capped with diphenylamino groups or dendrons based on triarylamine and carbazole moieties, OF(3)R´–R, R´ = Bu or Ph, R = H, NPh, or EG, have been synthesized by a convergent approach using palladium-catalyzed Suzuki cross-coupling or copper-catalyzed Buchwald’s amination as the key reaction. The functional properties, which include thermal stabilities, linear and non-linear optical properties, and fluorescence and electrochemical properties of the terfluorene derivatives are also investigated and discussed. The preliminary results show that end-capping of the terfluorene with diphenylamino groups, especially with dendrons, has been shown to offer advantages in terms of lowering the first ionization potential, enhancing thermal stability, and inducing good amorphous morphological stability of the resulting compounds.
Experience-dependent coding of facial expression in superior temporal sulcus
Authors: Furl Nicholas , van Rijsbergen Nicola J. , Treves Alessandro , Friston Karl J. , Dolan Raymond J.
Published: August 2007

Sensory information from the external world is inherently ambiguous, necessitating prior experience as a constraint on perception. Prolonged experience (adaptation) induces perception of ambiguous morph faces as a category different from the adapted category, suggesting sensitivity in underlying neural codes to differences between input and recent experience. Using magnetoencephalography, we investigated the neural dynamics of such experience-dependent visual coding by focusing on the timing of responses to morphs after facial expression adaptation. We show that evoked fields arising from the superior temporal sulcus (STS) reflect the degree to which a morph and adapted expression deviate. Furthermore, adaptation effects within STS predict the magnitude of behavioral aftereffects. These findings show that the STS codes expressions relative to recent experience rather than absolutely and may bias perception of expressions. One potential neural mechanism for the late timing of both effects appeals to hierarchical models that ascribe a central role to backward connections in mediating predictive codes.
4-Hydroxynonenal, an endogenous aldehyde, causes pain and neurogenic inflammation through activation of the irritant receptor TRPA1
Authors: Trevisani Marcello , Siemens Jan , Materazzi Serena , Bautista Diana M. , Nassini Romina , Campi Barbara , Imamachi Noritaka , Andrè Eunice , Patacchini Riccardo , Cottrell Graeme S. , Gatti Raffaele , Basbaum Allan I. , Bunnett Nigel W. , Julius David , Geppetti Pierangelo
Published: August 2007

TRPA1 is an excitatory ion channel expressed by a subpopulation of primary afferent somatosensory neurons that contain substance P and calcitonin gene-related peptide. Environmental irritants such as mustard oil, allicin, and acrolein activate TRPA1, causing acute pain, neuropeptide release, and neurogenic inflammation. Genetic studies indicate that TRPA1 is also activated downstream of one or more proalgesic agents that stimulate phospholipase C signaling pathways, thereby implicating this channel in peripheral mechanisms controlling pain hypersensitivity. However, it is not known whether tissue injury also produces endogenous proalgesic factors that activate TRPA1 directly to augment inflammatory pain. Here, we report that recombinant or native TRPA1 channels are activated by 4-hydroxy-2-nonenal (HNE), an endogenous α,β-unsaturated aldehyde that is produced when reactive oxygen species peroxidate membrane phospholipids in response to tissue injury, inflammation, and oxidative stress. HNE provokes release of substance P and calcitonin gene-related peptide from central (spinal cord) and peripheral (esophagus) nerve endings, resulting in neurogenic plasma protein extravasation in peripheral tissues. Moreover, injection of HNE into the rodent hind paw elicits pain-related behaviors that are inhibited by TRPA1 antagonists and absent in animals lacking functional TRPA1 channels. These findings demonstrate that HNE activates TRPA1 on nociceptive neurons to promote acute pain, neuropeptide release, and neurogenic inflammation. Our results also provide a mechanism-based rationale for developing novel analgesic or anti-inflammatory agents that target HNE production or TRPA1 activation.
The Synovial Sarcoma SYT-SSX2 Oncogene Remodels the Cytoskeleton through Activation of the Ephrin Pathway
Authors: Barco Roy , Hunt Laura B. , Frump Andrea L. , Garcia Christina B. , Benesh Andrew , Caldwell Robert L. , Eid Josiane E.
Published: August 2007

Synovial sarcoma is a soft tissue cancer associated with a recurrent t(X:18) translocation that generates one of two fusion proteins, SYT-SSX1 or SYT-SSX2. In this study, we demonstrate that SYT-SSX2 is a unique oncogene. Rather than confer enhanced proliferation on its target cells, SYT-SSX2 instead causes a profound alteration of their architecture. This aberrant morphology included elongation of the cell body and formation of neurite-like extensions. We also observed that cells transduced with SYT-SSX2 often repulsed one another. Notably, cell repulsion is a known component of ephrin signaling. Further analysis of SYT-SSX2–infected cells revealed significant increases in the expression and activation of Eph/ephrin pathway components. On blockade of EphB2 signaling SYT-SSX2 infectants demonstrated significant reversion of the aberrant cytoskeletal phenotype. In addition, we discovered, in parallel, that SYT-SSX2 induced stabilization of the microtubule network accompanied by accumulation of detyrosinated Glu tubulin and nocodazole resistance. Glu tubulin regulation was independent of ephrin signaling. The clinical relevance of these studies was confirmed by abundant expression of both EphB2 and Glu tubulin in SYT-SSX2–positive synovial sarcoma tissues. These results indicate that SYT-SSX2 exerts part of its oncogenic effect by altering cytoskeletal architecture in an Eph-dependent manner and cytoskeletal stability through a concurrent and distinct pathway.
Touch and Massage for Medically Fragile Infants
Authors: Livingston Karen , Beider Shay , Kant Alexis J. , Gallardo Constance C. , Joseph Michael H. , Gold Jeffrey I.
Published: August 2007

Research investigating the efficacy of infant massage has largely focused on premature and low birth weight infants. The majority of investigations have neglected highly acute patients in academic neonatal intensive care units (NICUs). The current study was developed with two aims: (Phase 1) to develop, implement and demonstrate the feasibility and safety of a parent‐trained compassionate touch/massage program for infants with complex medical conditions and (Phase 2) to conduct a longitudinal randomized control trial (RCT) of hand containment/massage versus standard of care in a level III academic Center for Newborn and Infant Critical Care (CNICC). Certified infant massage instructors (CIMIs) taught parents to massage their hospitalized infants. Massage therapy and instruction were performed for seven consecutive days and health outcomes were collected for up to 1 month following treatment. Caregivers, nurses and certified infant massage therapists indicated moderate to high levels of satisfaction and feasibility with the implementation of hand containment/massage in a level III academic center CNICC. In addition, infant behavioral and physiological measures were within safe limits during the massage sessions. All caregivers participating in the massage group reported high levels of satisfaction 7 days into the intervention and at the 1‐month follow‐up with regards to their relationship with their infant, the massage program′s impact on that relationship and the massage program. Due to unequal and small sample sizes, between group analyses (control versus massage) were not conducted. Descriptive infant characteristics of health outcomes are described. Preliminary data from this study indicates feasibility and safety of infant massage and satisfaction among the caregivers, CIMIs and the nurses in the CNICC. An important contribution from this study was the demonstration of the infants′ safety based on physiological stability and no change in agitation/pain scores of the infants receiving massage. Massage in a tertiary urban academic NICU continues to be an area of needed study. Future studies examining infant health outcomes, such as weight gain, decreased length of hospitalization and caregiver–infant bonding, would provide greater insight into the impact of massage for medically fragile infants.
The Same Allele of Translation Initiation Factor 4E Mediates Resistance Against Two Potyvirus spp. in Pisum sativum
Authors: Bruun-Rasmussen M. , Møller I. S. , Tulinius G. , Hansen J. K. R. , Lund O. S. , Johansen I. E.
Published: August 2007

Pathogenicity of two sequenced isolates of Bean yellow mosaic virus (BYMV) was established on genotypes of Pisum sativum L. reported to carry resistance genes to BYMV and other potyviruses. Resistance to the white lupin strain of BYMV (BYMV-W) is inherited as a recessive gene named wlv that maps to linkage group VI together with other Potyvirus resistances. One of these, sbm1, confers resistance to strains of Pea seedborne mosaic virus and previously has been identified as a mutant allele of the eukaryotic translation initiation factor 4E gene (eIF4E). Sequence comparison of eIF4E from BYMV-W-susceptible and –resistant P. sativum genotypes revealed a polymorphism correlating with the resistance profile. Expression of eIF4E from susceptible plants in resistant plants facilitated BYMV-W infection in inoculated leaves. When cDNA of BYMV-W was agroinoculated, resistance mediated by the wlv gene frequently was overcome, and virus from these plants had a codon change causing an Arg to His change at position 116 of the predicted viral genome-linked protein (VPg). Accordingly, plants carrying the wlv resistance gene were infected upon inoculation with BYMV-W derived from cDNA with a His codon at position 116 of the VPg coding region. These results suggested that VPg determined pathogenicity on plants carrying the wlv resistance gene and that wlv corresponded to the sbm1 allele of eIF4E.
The Chitin-Binding Cladosporium fulvum Effector Protein Avr4 Is a Virulence Factor
Authors: van Esse H. Peter , Bolton Melvin D. , Stergiopoulos Ioannis , de Wit Pierre J. G. M. , Thomma Bart P. H. J.
Published: August 2007

The biotrophic fungal pathogen Cladosporium fulvum (syn. Passalora fulva) is the causal agent of tomato leaf mold. The Avr4 protein belongs to a set of effectors that is secreted by C. fulvum during infection and is thought to play a role in pathogen virulence. Previous studies have shown that Avr4 binds to chitin present in fungal cell walls and that, through this binding, Avr4 can protect these cell walls against hydrolysis by plant chitinases. In this study, we demonstrate that Avr4 expression in Arabidopsis results in increased virulence of several fungal pathogens with exposed chitin in their cell walls, whereas the virulence of a bacterium and an oomycete remained unaltered. Heterologous expression of Avr4 in tomato increased the virulence of Fusarium oxysporum f. sp. lycopersici. Through tomato GeneChip analyses, we demonstrate that Avr4 expression in tomato results in the induced expression of only a few genes. Finally, we demonstrate that silencing of the Avr4 gene in C. fulvum decreases its virulence on tomato. This is the first report on the intrinsic function of a fungal avirulence protein that has a counter-defensive activity required for full virulence of the pathogen.
Elevated Genetic Variation Within Virulence-AssociatedBotrytis cinereaPolygalacturonase Loci
Authors: Rowe Heather C. , Kliebenstein Daniel J.
Published: August 2007

Botrytis cinerea, or gray mold, is a necrotrophic fungal pathogen of hundreds of plant species. The genetic diversity of B. cinerea may contribute to its broad host range; however, the level and structure of genetic variation at pathogenesis-associated loci has not been described. B. cinerea possesses six distinct cell-wall-degrading polygalacturonases (PGs), enzymes of demonstrated importance to pathogenesis and interaction with host plant defenses. Sequencing a collection of 34 B. cinerea isolates at three PG-encoding loci, BcPG1, BcPG2, and BcPG3, revealed limited evidence of host-mediated genetic subdivision within loci, yet suggested differences in the action of evolutionary forces among loci. BcPG1 and BcPG2 are highly polymorphic, particularly when compared with previously published data from nonpathogenicity loci, whereas BcPG3 is relatively conserved. Sequence variation at BcPG1 and BcPG2 did not appear to be associated with virulence on Arabidopsis leaves; however, BcPG2 variation showed a statistically significant association with growth rate on pectin. Rather than providing evidence for host-mediated genetic subdivision at individual PG loci, our data support specialization among PGs and the potential diversification of PGs interacting directly with host defenses.
Genomic Organization and Evolutionary Insights on GRP and NCR Genes, Two Large Nodule-Specific Gene Families in Medicago truncatula
Authors: Alunni Benoit , Kevei Zoltan , Redondo-Nieto Miguel , Kondorosi Adam , Mergaert Peter , Kondorosi Eva
Published: August 2007

Deciphering the mechanisms leading to symbiotic nitrogen-fixing root nodule organogenesis in legumes resulted in the identification of numerous nodule-specific genes and gene families. Among them, NCR and GRP genes encode short secreted peptides with potential antimicrobial activity. These genes appear to form large multigenic families in Medicago truncatula and other closely related legume species, whereas no similar genes were found in databases of Lotus japonicus and Glycine max. We analyzed the genomic organization of these genes as well as their evolutionary dynamics in the M. truncatula genome. A total of 108 NCR and 23 GRP genes have been mapped that were often clustered in the genome. These included 29 new NCR and 17 new GRP genes. Reverse transcription-polymerase chain reaction analyses of the novel genes confirmed their exclusive nodule-specific expression similar to the previously identified members. Protein alignments and phylogenetic analyses revealed traces of several duplication events in the history of GRP and NCR genes. Moreover, microsyntenic evidences between M. truncatula and L. japonicus validated the hypothesis that these genes are specific for the inverted repeat–lacking clade of hologalegoid legumes, which allowed dating the appearance of these two gene families during the evolution of legume plants.
T cell proliferation and cytokine responses to ovalbumin and ovomucoid detected in children with and without egg allergy
Authors: Tay S. S. , Clark A. T. , Deighton J. , King Y. , Ewan P. W.
Published: August 2007

Background
The specific T cell responses in egg allergy and resolution have not been fully elucidated.

Objective
To characterize egg allergen‐specific T cells of children with active and resolved egg allergy, in comparison with non‐allergic controls.

Method
We studied children with active (n=35) or resolved (n=20) egg allergy determined by oral challenge, and non‐allergic controls (n=15). Peripheral blood mononuclear cells were labelled with carboxyfluorescein succinimidyl ester (CFSE) and stimulated with ovalbumin (OVA), ovomucoid (OM) or tetanus toxoid. Flow cytometry was used to detect divided CD3+ CFSElo cells that expressed intra‐cytoplasmic IL‐4 or IFN‐γ. The cell division index (CDI) was calculated as a measure of allergen‐specific proliferation. Peanut‐specific T cells of a subgroup of children who also had peanut allergy were also studied.

Results
OVA‐specific T cells were found in subjects with active (87%) or resolved (75%) egg allergy and in controls (67%), with a trend towards increased T cell proliferation in allergy. OM‐induced weaker T cell responses than OVA, stimulating fewer responders (46% allergic, 50% resolved, 60% controls) and 10‐fold less proliferation [CDIOVA 2.0 (median), 25.6 (maximum) vs. CDIOM 0.2 (median), 15.1 (maximum); P<0.01]. Both egg allergens induced significant IL‐4+ (median 10%, range 1.4–58%) and IFN‐γ+ (median 28%, range 4.5–63%) cells in responders, including non‐allergics. There were no significant differences in IFN‐γ+ or IL‐4+ cells or in IFN‐γ/IL‐4 ratios between groups. Peanut‐specific T cell proliferation was significantly higher in peanut allergy [CDICPE 16.5 (median), 24.8 (maximum)] compared with controls [CDICPE 2.1 (median), 16.1 (maximum)] but cytokine profiles were not different. Tetanus‐specific T cells were seen in 90% of the subjects, with no significant inter‐group differences in responses.

Conclusion
Egg allergen‐specific T cells are readily detected in all groups and not restricted to egg allergy. In contrast, peanut‐specific proliferation was significantly higher in peanut allergy. This suggests that T cell responses in peanut and egg allergy may differ. We did not find T helper type 2‐deviated cytokine responses in egg or peanut allergy.
Measurement of basal growth hormone (GH) is a useful test of disease activity in treated acromegalic patients
Authors: Jayasena C. N. , Wujanto C. , Donaldson M. , Todd J. F. , Meeran K.
Published: August 2007

Background  Nadir GH during oral glucose tolerance test (OGTT) is the gold‐standard test of GH secretion in treated acromegaly. However, it was recently reported that variability in GH is reduced postradiotherapy, making basal GH a potential surrogate marker for nadir GH in such patients.

Objective  We aimed to investigate how predictive basal GH is of nadir GH and IGF‐I, and whether radiotherapy influenced these relationships.

Design  A total of 226 pairs of basal and nadir GH values from 76 treated acromegalic patients were analysed. Basal GH was defined as the fasting serum GH immediately prior to OGTT.

Results  A highly positive linear correlation (Pearson correlation = 0·955, P < 0·01) between basal and nadir GH was found. Negative predictive value for basal GH < 1 µg/l with respect to nadir GH > 1 µg/l was 100% (53/53 in radiotherapy group, 15/15 in nonradiotherapy group). Positive predictive values for basal GH > 2 µg/l with respect to nadir GH > 1 µg/l for patients treated and not treated with radiotherapy were 96·7% (88/91) and 95·2% (20/21), respectively. No significant difference between concordance of basal and nadir GH with IGF‐I in assessment of disease activity was found. Discordance between IGF‐I and nadir or basal GH < 1 µg/l was lower in the radiotherapy group than nonradiotherapy group, but this was nonsignificant.

Conclusions  Basal GH < 1 µg/l and > 2 µg/l are highly predictive of nadir GH < 1 µg/l and > 1 µg/l, respectively, regardless of previous radiotherapy. Basal GH is as good as nadir GH in concordance with IGF‐I. We therefore suggest basal GH is a useful test of disease activity in treated acromegaly, and can reliably replace OGTT unless basal GH is between 1 µg/l and 2 µg/l.