bluuebunny/crossref_metadata_2025 huggingface dataset:
Gastroesophageal Reflux Disease: A Gastroenterologist's Perspective
Authors: Vaezi Michael F.
Published: November 2011

Gastroesophageal reflux disease (GERD) is a commonly diagnosed condition often associated with the typical symptoms of heartburn and regurgitation, although it may present with atypical symptoms such as chest pain, hoarseness, chronic cough, and asthma. In most cases, the patient's reduced quality of life drives clinical care and diagnostic testing. Because of its widespread impact on voice and swallowing function as well as its social implications, it is important that speech-language pathologists (SLPs) understand the nature of GERD and its consequences. The purpose of this article is to summarize the nature of GERD and GERD-related complications such as GERD-related peptic stricture, Barrett's esophagus and adenocarcinoma, and laryngeal manifestations of GERD from a gastroenterologist's perspective. It is critical that SLPs who work with a multidisciplinary team understand terminology, diagnostic tools, and treatment to ensure best practice.
Orthopédie dento-faciale et ostéopathie
Authors: Fournier Romain , Aknin Jean-Jacques , Bourgier Sophie , Gebeile-Chauty Sarah
Published: November 2011

L’ostéopathie connaît un engouement croissant. Compte tenu de leur action commune sur les
enfants et les adolescents, la collaboration entre l’orthopédie dento-faciale et
l’ostéopathie est de plus en plus fréquente. Il devient donc nécessaire et urgent de
rechercher si, selon les données acquises de la science, il existe une preuve des
inter-relations possibles entre les deux disciplines. Après revue de la littérature, peu
de publications scientifiques prouvent l’utilité de l’ostéopathie et ses relations avec
d’autres disciplines. Pourtant, des relations entre occlusion et posture ont été montrées
– sans qu’il s’agisse à proprement parler de preuve scientifique –, notamment dans le sens
sagittal. D’autre part, bien que la mobilité des os du crâne soit établie, le mouvement
respiratoire primaire est toujours sujet à controverses, y compris parmi les ostéopathes.
Cela alors même que l’orthopédie dento-faciale a été longtemps accusée de contrer le
mouvement respiratoire primaire des os crâniens (MRP). Aujourd’hui, les ostéopathes ne
rejettent plus l’orthodontie car le retour à une situation occlusale saine est considéré
comme bénéfique. Selon les avis d’experts – sans preuve toutefois – certains appareils
d’orthodontie (forces extra-buccales, disjoncteurs, etc.), qui bloquent les sutures,
seraient néanmoins à éviter et nécessitent le cas échéant un suivi ostéopathique. Les
polémiques sur les effets néfastes de l’orthodontie étant de plus en plus nuancées de la
part des ostéopathes et l’orthodontie moderne se réclamant d’une approche « globale » du
patient, une collaboration sera peut-être possible dans les années à venir.
Magnetic properties of Fe80−xCoxZr7Si13 (x = 0 – 30) amorphous alloys
Authors: Kopcewicz M. , Grabias A. , Latuch J.
Published: November 2011

Amorphous Fe80−xCoxZr7Si13 (x = 0 – 30) alloys, in which boron was completely replaced by silicon as a glass forming element, have been prepared by melt quenching. Partial substitution of iron by cobalt causes the increase of the hyperfine fields from about 19 to 27 T for x = 0 and 30, respectively, as revealed by conventional Mössbauer spectroscopy. The specialized rf-Mössbauer technique permitted us to estimate the soft magnetic properties of the alloys. The rf-collapse effect, which is very sensitive to the local anisotropy field, is observed for all amorphous FeCoZrSi alloys revealing that they are magnetically very soft. The rf-sidebands intensities, which are related to the magnetostriction, increase with the increase of Co content in the alloys. In Fe60Co20Zr7Si13 and Fe50Co30Zr7Si13 samples the rf field exposure induced partial crystallization that was attributed to mechanical deformations related to high frequency magnetostrictive vibrations forced by the rf field. The magnetostrictive origin of this effect was supported by the measurements of magnetostriction constants of the studied alloys. Measurements of the hysteresis loops revealed that coercivity increases for higher Co content.
Microstructure dependence of dynamic fracture and yielding in aluminum and an aluminum alloy at strain rates of 2 × 106 s−1 and faster
Authors: Dalton D. A. , Worthington D. L. , Sherek P. A. , Pedrazas N. A. , Quevedo H. J. , Bernstein A. C. , Rambo P. , Schwarz J. , Edens A. , Geissel M. , Smith I. C. , Taleff E. M. , Ditmire T.
Published: November 2011

Experiments investigating fracture and resistance to plastic deformation at fast strain rates (>106 s−1) were performed via laser ablation on thin sheets of aluminum and aluminum alloys. Single crystal high purity aluminum (Al-HP) and a single crystal 1100 series aluminum alloy (AA1100) were prepared to investigate the role of impurity particles. Specimens of aluminum alloy +3 wt. % Mg (Al+3Mg) at three different grain sizes were also studied to determine the effect of grain size. In the present experiments, high purity aluminum (Al-HP) exhibited the highest spall strength over 1100 series aluminum alloy (AA1100) and Al+3Mg. Fracture characterization and particle analysis revealed that fracture was initiated in the presence of particles associated with impurity content in the AA1100 and at both grain boundaries and particles in Al+3Mg. The Al+3Mg specimens exhibited the greatest resistance to plastic deformation likely resulting from the presence of magnesium atoms. The Al-HP and AA1100, both lacking a strengthening element such as Mg, were found to have the same Hugoniot elastic limit (HEL) stress. Within the single crystal specimens, orientation effects on spall strength and HEL stress appear to be negligible. Although the fracture character shows a trend with grain size, no clear dependence of spall strength and HEL stress on grain size was measured for the Al+3Mg. Hydrodynamic simulations show how various strength and fracture models are insufficient to predict material behavior at fast strain rates, and a revised set of Tuler-Butcher coefficients for spall are proposed.
Liquid helium inertial jet for comparative study of classical and quantum turbulence
Authors: Duri D. , Baudet C. , Charvin P. , Virone J. , Rousset B. , Poncet J.-M. , Diribarne P.
Published: November 2011

We present a new cryogenic wind tunnel facility developed to study the high Reynolds number developed classical or quantum turbulence in liquid 4He. A stable inertial round jet flow with a Reynolds number of 4 × 106 can be sustained in both He I and He II down to a minimum temperature of 1.7 K. The circuit can be pressurized up to 3.5 × 105 Pa. The system has been designed to exploit the self-similar properties of the jet far field in order to adapt to the spatial resolution of the existing probes. Multiple and complementary sensors can be simultaneously installed to obtain spatial and time resolved measurements. The technical difficulties and design details are described and the system performance is presented.
Resonant phenomenon of elliptical cylinder flows in a subcritical regime
Authors: Chen Shih-Sheng , Yen Ruey-Hor
Published: November 2011

The resonant phenomena in the wake behind a transversely vibrating elliptical cylinder with different axis ratios from Ar = 0.01 to Ar = 2.0 in the subcritical regime is numerically investigated. Navier-Stokes equations are solved by a spectral element code with a triangular mesh. Reynolds numbers range from 15 to 60 and the Roshko numbers range from 0.5 to 8 for different elliptical cylinders. Both the velocity and pressure responses in the wake are measured and analyzed. The investigations of the drag coefficients and the wake streamlines indicate that the cylinder’s axis ratio has a minor effect on the resonant frequency, Ron. However, the cylinder’s axis ratio is found to have a prominent effect on the resonant amplitude; namely, the smaller the cylinder’s axis ratio, the stronger the occurrence of resonant amplitude. The investigations of resonant responses of both the velocity and pressure and the probe locations may provide information for designing a flow meter based on pressure responses in the subcritical regime. It shows that the ratio of velocity and pressure responses poses a great linear relationship against the probe distance behind the vibrating cylinder. Moreover, a resonant method based on the different resonant frequencies at different probed locations in the subcritical regime to predict the critical conditions is examined and verified for different elliptical cylinders. Finally, based on the critical values found, a reduced Reynolds number and a reduced Roshko number are proposed to unify the different linear relationships resulting from different elliptical cylinder flows. The result indicates that the effect of axis ratio can be stripped off in the reduced plane, which may be applied to a more generalized cylinder shape.
Stern-Gerlach deflection of field-free aligned paramagnetic molecules
Authors: Gershnabel E. , Shapiro M. , Averbukh I. Sh.
Published: November 2011

The effects of laser-induced pre-alignment on the deflection of paramagnetic molecules by inhomogeneous static magnetic field are studied. Depending on the relevant Hund's coupling case of the molecule, two different effects were identified: either suppression of the deflection by laser pulses (Hund's coupling case (a) molecules, such as \documentclass[12pt]{minimal}\begin{document}$\text{ClO}$\end{document}ClO), or a dramatic reconstruction of the broad distribution of the scattering angles into several narrow peaks (for Hund's coupling case (b) molecules, such as \documentclass[12pt]{minimal}\begin{document}$\text{O}_2$\end{document}O2 or \documentclass[12pt]{minimal}\begin{document}$\text{NH}$\end{document}NH). These findings are important for various applications using molecular guiding, focusing and trapping with the help of magnetic fields.
Analyzing two electroluminescence modes of indium tin oxide/α-NPD/Alq3/Al diodes by using large alternating current square voltages
Authors: Sadakata Atsuo , Taguchi Dai , Yamamoto Tetsuya , Fukuzawa Masahiro , Manaka Takaaki , Iwamoto Mitsumasa
Published: November 2011

By applying large A.C. square voltages to double-layer ITO/α-NPD/Alq3/Al diodes, we studied the generation of electroluminescence (EL) in terms of the carrier injection and transport. The EL intensity gradually decayed with the increase of the frequency of the applied A.C. square voltage, and reached a minimum at the frequency corresponding to the carrier transit time. Interestingly, the EL intensity was again increased by the application of further higher frequency A.C. square voltages, relying on the D.C. component of the A.C. square voltages. The results suggest the presence of two EL modes. Using the Maxwell-Wagner effect model analysis, we have proposed a model that accounts for the two EL modes.
Dielectric relaxation near 25 K in multiferroic BiFeO3 ceramics
Authors: Ramachandran B. , Dixit A. , Naik R. , Lawes G. , Ramachandra Rao M. S.
Published: November 2011

Our investigations using low-temperature Raman spectroscopy, dielectric, and magnetodielectric studies of as-prepared and vacuum-annealed BiFeO3 ceramics revealed two dielectric anomalies near 25 and 281 K. Systematic studies were carried out to probe the anomaly near 25 K which exhibits clear frequency dependence and falls close to a previously observed magnetic transition. The low-temperature dielectric relaxation behavior yielded characteristic energy scales of ∼30 and ∼34 meV for the as-prepared and vacuum-annealed BiFeO3 samples, respectively. Raman spectra showed hardening of the E(TO6) and E(TO9) modes near 25 K, and the Raman shift in phonon frequencies is found to be broader in the vacuum-annealed BiFeO3 than in the as-prepared BiFeO3. We observed a linear magnetodielectric coupling in both samples at 25 K. These experimental results suggest that coupling among spin, lattice, and dielectric properties persist to low temperatures in BiFeO3.
Nanoscale oxygen nonstoichiometry in epitaxial TiO2 films grown by pulsed laser deposition
Authors: Takata Shintaro , Tanaka Ryohei , Hachiya Atsushi , Matsumoto Yuji
Published: November 2011

Nanoscale control of oxygen nonstoichiometry in oxide thin films has become more and more important as the characteristic sizes of oxide devices have been reduced to the nanometer scale. We propose a new in situ electrochemical approach for nanoscale characterization of oxygen stoichiometry in epitaxial oxide thin films. For this purpose, we have developed a pulsed laser deposition system equipped with an electrochemical analysis cell. In situ characterization of homoepitaxial TiO2 thin films by a combination of reflection high-energy electron diffraction and Mott-Schottky analysis has revealed that the lattice oxygen in the TiO2 film subsurface region up to a depth of about 10 nm can be easily lost or gained, depending on temperature and the ambient oxygen pressure. This unavoidably results in a nanoscale inhomogeneous distribution of oxygen vacancies in TiO2 films.
Sn diffusion during Ni germanide growth on Ge1–xSnx
Authors: Demeulemeester J. , Schrauwen A. , Nakatsuka O. , Zaima S. , Adachi M. , Shimura Y. , Comrie C. M. , Fleischmann C. , Detavernier C. , Temst K. , Vantomme A.
Published: November 2011

We report on the redistribution of Sn during Ni germanide formation on Ge1–xSnx/〈Ge(100)〉 and its influence on the thin film growth and properties. These results show that the reaction involves the formation of Ni5Ge3 and NiGe. Sn redistributes homogenously in both phases, in which the Sn/Ge ratio retains the ratio of the as-deposited Ge1–xSnx film. Sn continues to diffuse after full NiGe formation and segregates in two regions: (1) at the interface between the germanide and Ge1–xSnx and (2) at the surface, which has major implications for the thin film and contact properties.
Phase separation in strained epitaxial InGaN islands
Authors: Niu Xiaobin , Stringfellow Gerald B. , Liu Feng
Published: November 2011

Phase separation (PS) produces InN composition gradients in InGaN islands, which may be important for light emitting diodes, solar cells, and lasers. Thus, the control of PS is critical, and the kinetic growth process, which is suggested to be important for controlling PS in Stranski-Krastanov islands, becomes a key factor in producing materials for optoelectronic devices. We present atomistic-strain-model Monte Carlo simulations for PS in strained epitaxial InGaN islands. Our simulations illustrate how the PS in InGaN islands depends on the kinetic growth mode and subsurface diffusion, and thus suggest ideas for controlling the microstructure of alloy islands formed during epitaxial growth.
Surface acoustic wave micromotor with arbitrary axis rotational capability
Authors: Tjeung Ricky T. , Hughes Mark S. , Yeo Leslie Y. , Friend James R.
Published: November 2011

A surface acoustic wave (SAW) actuated rotary motor is reported here, consisting of a millimeter-sized spherical metal rotor placed on the surface of a lead zirconate titanate piezoelectric substrate upon which the SAW is made to propagate. At the design frequency of 3.2 MHz and with a fixed preload of 41.1 μN, the maximum rotational speed and torque achieved were approximately 1900 rpm and 5.37 μN-mm, respectively, producing a maximum output power of 1.19 μW. The surface vibrations were visualized using laser Doppler vibrometry and indicate that the rotational motion arises due to retrograde elliptical motions of the piezoelectric surface elements. Rotation about orthogonal axes in the plane of the substrate has been obtained by using orthogonally placed interdigital electrodes on the substrate to generate SAW impinging on the rotor, offering a means to generate rotation about an arbitrary axis in the plane of the substrate.
Pyroelectric properties of rhombohedral and tetragonal Pb(In1/2Nb1/2)-Pb(Mg1/3Nb2/3)-PbTiO3 crystals
Authors: Gao Junjie , Xu Zhuo , Li Fei , Zhang Chonghui , Li Zhenrong , Wu Xiaoqing , Wang Linghang , Liu Yi , Liu Gaomin , He Hongliang
Published: November 2011

Pyroelectric properties of rhombohedral and tetragonal single crystals Pb(In1/2Nb1/2)-Pb(Mg1/3Nb2/3)-PbTiO3 (PIN-PMN-PT) were investigated, with temperature from −100 °C to 100 °C. At room temperature, the pyroelectric coefficient p and the figure of merit Fd of rhombohedral crystals are 7.81 × 10−4 C/m2 K and 10.9 × 10−5 Pa−1/2, respectively, and 6.84 × 10−4 C/m2 K and 11.67 × 10−5 Pa−1/2, respectively, for tetragonal crystals. Although the coefficient p and Fd at room temperature are similar for rhombohedral and tetragonal crystals, the Fd of tetragonal crystal is much more stable with respect to temperature, owing to its higher phase transition temperature and stable mono-domain state. From room temperature to 100 °C, the Fd of rhombohedral crystal decreases from 10.74 × 10−5 Pa−1/2 to 5.3 × 10−5 Pa−1/2, while that of tetragonal crystals is nearly independent of temperature. Such investigation reveals that tetragonal PIN-PMN-PT crystal is more suitable for uncooled infrared detectors and imagers when compared with its rhombohedral counterpart.
Pressure-induced magnetoresistivity reversal in magnetite
Authors: Su Ningning , Han Yonghao , Ma Yanzhang , Liu Hongwu , Ma Boheng , Gao Chunxiao
Published: November 2011

The magnetoresistivity (MR) of nano-powdered magnetite has been measured under pressures up to 19.0 GPa and magnetic fields up to 15 kG. An unexpected quasi-linear positive MR below 6.0 GPa and an MR transition from positive to negative around 6.0 GPa have been found. The abnormal positive MR below 6.0 GPa originates from the confinement effect caused by nano-scale heterogeneity at the contact surface between Mo and Fe3O4 sample and the high negative spin polarization of magnetite. The MR transition at about 6.0 GPa comes from a phase transition from half-metal to metal induced by pressure.
Wireless energy transfer with the presence of metallic planes
Authors: Yu Xiaofang , Sandhu Sunil , Beiker Sven , Sassoon Richard , Fan Shanhui
Published: November 2011

We numerically demonstrated that efficient wireless energy transfer can be achieved between two high Q resonators in a complex electromagnetic environment. In particular, in the close proximity of metallic planes, efficient wireless energy transfer can be achieved with proper system designs.
Effects of Sr content and bias field on acoustic properties of strontium barium niobate studied by Brillouin light scattering
Authors: Ko Jae-Hyeon , Kim Tae Hyun , Kojima Seiji , Lim Ki-Soo , Koo Tae-Yeong
Published: November 2011

The effects of Sr/Ba ratio and bias field on the acoustic anomalies of SrxBa1−xNb2O6 (SBN − x) were investigated by Brillouin scattering. The “critical” part in the elastic constant and the absorption coefficient increased linearly with decreasing Sr content. This was attributed to the enhanced coupling between the polarization and the strain due to the formation of quasistatic polar regions in the paraelectric phase. The field-cooling of SBN-0.61 induced discontinuous changes in the elastic properties with some remnant relaxor signature. This was tentatively ascribed to the persisting polar nanoregions that were not aligned due to quenched random fields.
Effect of electron injection into phosphorus donors in silicon-on-insulator channel observed by Kelvin probe force microscopy
Authors: Anwar Miftahul , Nowak Roland , Moraru Daniel , Udhiarto Arief , Mizuno Takeshi , Jablonski Ryszard , Tabe Michiharu
Published: November 2011

We have comparatively studied the effects of electron injection in individual phosphorus-donor potential wells at 13 K and 300 K by Kelvin probe force microscopy in silicon-on-insulator metal-oxide-semiconductor field-effect-transistors. As a result, at 13 K, localized single-electron filling into the phosphorus-donor potential well is found, reflecting single-electron tunneling transport through individual donors, whereas at 300 K, spatially extended and continuous electron filling over a number of phosphorus-donors is observed, reflecting drift-diffusion transport.
Electrowetting based infrared lens using ionic liquids
Authors: Hu Xiaodong , Zhang Shiguo , Liu Yu , Qu Chao , Lu Liujin , Ma Xiangyuan , Zhang Xiaoping , Deng Youquan
Published: November 2011

We demonstrated an infrared variable focus ionic liquids lens using electrowetting, which could overcome the problems caused by use of water, e.g., evaporation and poor thermostability, while keeping good optical transparency in visible light and near-infrared region. Besides, the type of lens (convex or concave) could be tuned by applied voltage or refractive index of ILs used, and the transmittance was measured to exceed 90% over the spectrum of visible light and near-infrared. We believe this infrared variable focus ionic liquids lens has a great application prospect in both visible light and infrared image systems.
A high-reflectivity, ambient-stable graphene mirror for neutral atomic and molecular beams
Authors: Sutter P. , Minniti M. , Albrecht P. , Farías D. , Miranda R. , Sutter E.
Published: November 2011

We report a He and H2 diffraction study of graphene-terminated Ru(0001) thin films grown epitaxially on c-axis sapphire. Even for samples exposed for several weeks to ambient conditions, brief annealing in ultrahigh vacuum restored extraordinarily high specular reflectivities for He and H2 beams (23% and 7% of the incident beam, respectively). The quality of the angular distributions recorded with both probes exceeds the one obtained from in-situ prepared graphene on Ru(0001) single crystals. Our results for graphene-terminated Ru thin films represent a significant step toward ambient tolerant, high-reflectivity curved surface mirrors for He-atom microscopy.
Communication: Standard surface hopping predicts incorrect scaling for Marcus’ golden-rule rate: The decoherence problem cannot be ignored
Authors: Landry Brian R. , Subotnik Joseph E.
Published: November 2011

We evaluate the accuracy of Tully's surface hopping algorithm for the spin-boson model for the case of a small diabatic coupling parameter (V). We calculate the transition rates between diabatic surfaces, and we compare our results to the expected Marcus rates. We show that standard surface hopping yields an incorrect scaling with diabatic coupling (linear in V), which we demonstrate is due to an incorrect treatment of decoherence. By modifying standard surface hopping to include decoherence events, we recover the correct scaling (∼V2).
Communication: A global hybrid generalized gradient approximation to the exchange-correlation functional that satisfies the second-order density-gradient constraint and has broad applicability in chemistry
Authors: Peverati Roberto , Truhlar Donald G.
Published: November 2011

We extend our recent SOGGA11 approximation to the exchange-correlation functional to include a percentage of Hartree-Fock exchange. The new functional, called SOGGA11-X, has better overall performance for a broad chemical database than any previously available global hybrid generalized gradient approximation, and in addition it satisfies an extra physical constraint in that it is correct to second order in the density-gradient.
Strain dependent resistance in chemical vapor deposition grown graphene
Authors: Fu Xue-Wen , Liao Zhi-Min , Zhou Jian-Xin , Zhou Yang-Bo , Wu Han-Chun , Zhang Rui , Jing Guangyin , Xu Jun , Wu Xiaosong , Guo Wanlin , Yu Dapeng
Published: November 2011

The strain dependence of conductance of monolayer graphene has been studied experimentally here. The results illustrate the notable transitions: the slight increase, the dramatic decrease, and the sudden dropping of the conductance by gradually increasing the uniaxial strain. The graphene conductance behaves reversibly by tuning of the elastic tensile strain up to 4.5%, while it fails to recover after the plastic deformation at 5%. The change in conductance due to strain is surprisingly high, which indicates the potential applications in electromechanical devices.
Metal nanoparticles in a photovoltaic cell: Effect of metallic loss
Authors: Watanabe Ryosuke , Miyano Kenjiro
Published: November 2011

We examined numerically the contribution of contrasting characteristics of metal nanoparticles, strong polarization and metallic loss, to the total efficiency of photovoltaic cells. A layer of nanoparticle array was chosen as a model. We found that depending on the location of the layer in the cell, the metallic loss offsets the enhanced photoabsorption due to the strong near field. A general procedure to reduce a nanoparticle layer into a sheet of effective continuous medium is presented, which greatly facilitates the quantitative analysis.
Individual and Population Quantitative Analyses of Calcium Flux in T-Cells Activated on Functionalized Material Surfaces
Authors: Christo Susan N. , Sarvestani Ghafar.T. , Griesser Stefani S. , Coad Bryan R. , Griesser Hans J. , Vasilev Krasimir , Brown Michael P. , Diener Kerrilyn R. , Hayball John D.
Published: November 2011

We have developed a novel method for activating T-cells on material surfaces that enable individual and population-based analyses of intracellular calcium flux, as a quantitative measure of T-cell receptor engagement. Functionalized material surfaces were created using a plasma-polymerized foundation layer to immobilize stimulatory T-cell ligands, which could induce T-cell receptor-dependent calcium flux in naive T-cells. Real-time confocal microscopic detection and quantification of calcium flux using paired fluorescent ratiometric probes facilitated the tracking and analysis of response profiles of individual T-cells, as well as population analyses using a combination of individual T-cell events. This type of combined analysis cannot be achieved using traditional population-based flow cytometric approaches, and thus provides a logical step towards developing the capacity to assess the magnitude and quality of inherently heterogeneous effector T-cell responses to antigenic challenge.
UV-induced emissions of C2 - C5 hydrocarbons from leaf litter
Authors: Derendorp Leonie , Holzinger Rupert , Röckmann Thomas
Published: November 2011

Environmental contextLeaf litter can be found at the Earth’s surface in large quantities, and has the potential to release significant amounts of volatile compounds into the atmosphere where they influence atmospheric chemistry and local air quality. This study investigates the influence of UV radiation on the emission of C2–C5 hydrocarbons from leaf litter. Research on volatile compound emissions from leaf litter is limited, but essential for establishing their global budgets and understanding atmospheric chemistry.
AbstractLeaf litter is available at many locations at the Earth’s surface. It has the potential to emit many different types of volatile organic compounds (VOCs) into the atmosphere, which may influence local atmospheric chemistry and air quality. In this study, emissions of several C2–C5 hydrocarbons from leaf litter were measured for different plant species and the influence of ultraviolet (UV) radiation on the emissions was determined. Within the ambient range of UV intensities, the emission rates increased linearly with the intensity of the UV radiation. UVB radiation (280–320 nm) was more efficient in the generation of hydrocarbons from leaf litter than UVA (320–400 nm). In the absence of oxygen, no emissions of C2–C5 hydrocarbons were observed. When leaf litter was placed in humid air, emission rates approximately tripled compared with emissions from leaf litter in dry air. Decay of the emission rates was visible on a timescale of months. A simple upscaling showed that UV-induced hydrocarbon emissions from leaf litter might have a small influence on atmospheric chemistry on the local scale, but do not contribute significantly to their global budgets.
Cadmium and nickel uptake by tomato and spinach seedlings: plant or transport control?
Authors: Degryse Fien , Smolders Erik
Published: November 2011

Environmental contextUptake of metal ions by plants is often predicted with equilibrium models, which assume that the rate limiting step is trans-membrane uptake of the metal in the roots rather than the transport of the metal ion towards the site of uptake. Evidence is given that uptake of cadmium by plants is under strong transport control at environmentally relevant concentrations, whereas nickel uptake borders between transport and plant control. This explains the lack of ion competition effects for Cd uptake, whereas both proton and Mg ions were found to compete with Ni uptake.
AbstractEquilibrium models for metal uptake by biota assume that the uptake is rate limited by the internalisation of the metal across the cell membrane (plant control). However, evidence has been found that Cd uptake by plants is controlled by the diffusive transport of the free ion to the root at low Cd2+ activities. In this study, the uptake of Cd and Ni by tomato and spinach in nutrient solution was compared to assess whether Ni uptake is under plant or transport control. The diffusive gradient in thin films (DGT) technique was used to measure the maximal diffusive flux. In unbuffered solutions, the uptake flux of Ni was approximately three-fold smaller than that of Cd at free ion concentrations below 1 µM. Stirring the solution increased the uptake of Cd, but not that of Ni at low free ion concentration. The presence of DGT-labile complexes increased the uptake of Cd, but not that of Ni, except at high pH (pH 7). Increasing the solution pH increased Cd uptake only when solution Cd2+ activities were strongly buffered. Overall, the results indicated that the Cd uptake was strongly diffusion limited and that uptake is likely to be under transport control in natural environments. Uptake of nickel, on the other hand, appears to be at the border between plant and transport control. This finding has practical applications, e.g. competition effects at the root have little effect on Cd uptake and chelator-assisted phytoextraction is expected to have less effect for Ni than for Cd.
Dual role of methionyl-tRNA synthetase in the regulation of translation and tumor suppressor activity of aminoacyl-tRNA synthetase-interacting multifunctional protein-3
Authors: Kwon Nam Hoon , Kang Taehee , Lee Jin Young , Kim Hyo Hyun , Kim Hye Rim , Hong Jeena , Oh Young Sun , Han Jung Min , Ku Min Jeong , Lee Sang Yeol , Kim Sunghoon
Published: November 2011

Mammalian methionyl-tRNA synthetase (MRS) plays an essential role in initiating translation by transferring Met to initiator tRNA (tRNAiMet). MRS also provides a cytosolic anchoring site for aminoacyl-tRNA synthetase-interacting multifunctional protein-3 (AIMP3)/p18, a potent tumor suppressor that is translocated to the nucleus for DNA repair upon DNA damage. However, the mechanism by which this enzyme mediates these two seemingly unrelated functions is unknown. Here we demonstrate that AIMP3 is released from MRS by UV irradiation-induced stress. Dissociation was induced by phosphorylation of MRS at Ser662 by general control nonrepressed-2 (GCN2) following UV irradiation. Substitution of Ser662 to Asp (S662D) induced a conformational change in MRS and significantly reduced its interaction with AIMP3. This mutant possessed significantly reduced MRS catalytic activity because of loss of tRNAMetbinding, resulting in down-regulation of global translation. According to the Met incorporation assay using stable HeLa cells expressing MRS S662A or eukaryotic initiation factor-2 subunit-α (eIF2α) S51A, inactivation of GCN2-induced phosphorylation at eIF2α or MRS augmented the role of the other, suggesting a cross-talk between MRS and eIF2α for efficient translational inhibition. This work reveals a unique mode of regulation of global translation as mediated by aminoacyl-tRNA synthetase, specifically MRS, which we herein identified as a previously unidentified GCN2 substrate. In addition, our research suggests a dual role for MRS: (i) as a coregulator with eIF2α for GCN2-mediated translational inhibition; and (ii) as a coupler of translational inhibition and DNA repair following DNA damage by releasing bound tumor suppressor AIMP3 for its nuclear translocation.
Bacterial chemotaxis modulates host cell apoptosis to establish a T-helper cell, type 17 (Th17)-dominant immune response in
Helicobacter pylori
infection
Authors: Rolig Annah S. , Carter J. Elliot , Ottemann Karen M.
Published: November 2011

The host inflammatory response to chronic bacterial infections often dictates the disease outcome. In the case of the gastric pathogen
Helicobacter pylori
, host inflammatory responses result in outcomes that range from moderate and asymptomatic to more severe with concomitant ulcer or cancers. It was found recently that
H. pylori
chemotaxis mutants (Che
−
), which lack directed motility but colonize to nearly wild-type levels, trigger less host inflammation. We used these mutants to observe host immune responses that resulted in reduced disease states. Here we report that these mutants are defective for early gastric recruitment of CD4
+
T cells compared with wild-type infection. Furthermore, Che
−
mutant infections lack the T-helper cell, type 17 (Th17) component of the immune response, as measured by cytokine mRNA levels in gastric tissue via intracellular cytokine staining and immunofluorescence. We additionally find that a Che
−
mutant infection results in significantly less host cell apoptosis than does wild-type infection, in accordance with previous observations that T-helper cell, type 17 responses in
Citrobacter rodentium
infections are driven by concomitant bacterial and apoptotic cell signals. We propose that bacterial chemotaxis allows
H. pylori
to access a particular host niche that allows the bacteria to express or deliver proapoptotic host cell factors. This report indicates that chemotaxis plays a role in enhancing apoptosis, suggesting bacterial chemotaxis systems might serve as therapeutic targets for infections whose symptoms arise from host cell apoptosis and tissue damage.
Independent recruitments of a translational regulator in the evolution of self-fertile nematodes
Authors: Beadell Alana V. , Liu Qinwen , Johnson Dorothy M. , Haag Eric S.
Published: November 2011

Pleiotropic developmental regulators have been repeatedly linked to the evolution of anatomical novelties. Known mechanisms include
cis
-regulatory DNA changes that alter regulator transcription patterns or modify target-gene linkages. Here, we examine the role of another form of regulation, translational control, in the repeated evolution of self-fertile hermaphroditism in
Caenorhabditis
nematodes.
Caenorhabditis elegans
hermaphrodites initiate spermatogenesis in an otherwise female body through translational repression of the gene
tra-2.
This repression is mediated by GLD-1, an RNA-binding protein also required for oocyte meiosis and differentiation. By contrast, we show that in the convergently hermaphroditic
Caenorhabditis briggsae
, GLD-1 acts to promote oogenesis. The opposite functions of
gld-1
in these species are not gene-intrinsic, but instead result from the unique contexts for its action that evolved in each. In
C. elegans
, GLD
-
1 became essential for promoting XX spermatogenesis via changes in the
tra-2
mRNA and evolution of the species-specific protein FOG-2.
C. briggsae
GLD-1 became an essential repressor of sperm-promoting genes, including
Cbr-puf-8
, and did not evolve a strong association with
tra-2
. Despite its variable roles in sex determination, the function of
gld-1
in female meiotic progression is ancient and conserved. This conserved role may explain why
gld-1
is repeatedly recruited to regulate hermaphroditism. We conclude that, as with transcription factors, spatially localized translational regulators play important roles in the evolution of anatomical novelties.
Fitness costs limit influenza A virus hemagglutinin glycosylation as an immune evasion strategy
Authors: Das Suman R. , Hensley Scott E. , David Alexandre , Schmidt Loren , Gibbs James S. , Puigbò Pere , Ince William L. , Bennink Jack R. , Yewdell Jonathan W.
Published: November 2011

Here, we address the question of why the influenza A virus hemagglutinin (HA) does not escape immunity by hyperglycosylation. Uniquely among dozens of monoclonal antibodies specific for A/Puerto Rico/8/34, escape from H28-A2 neutralization requires substitutions introducing N-linked glycosylation at residue 131 or 144 in the globular domain. This escape decreases viral binding to cellular receptors, which must be compensated for by additional substitutions in HA or neuraminidase that enable viral replication. Sequence analysis of circulating H1 influenza viruses confirms the in vivo relevance of our findings: natural occurrence of glycosylation at residue 131 is always accompanied by a compensatory mutation known to increase HA receptor avidity. In vaccinated mice challenged with WT vs. H28-A2 escape mutants, the selective advantage conferred by glycan-mediated global reduction in antigenicity is trumped by the costs of diminished receptor avidity. These findings show that, although N-linked glycosylation can broadly diminish HA antigenicity, fitness costs restrict its deployment in immune evasion.
Arenavirus Z protein controls viral RNA synthesis by locking a polymerase–promoter complex
Authors: Kranzusch Philip J. , Whelan Sean P. J.
Published: November 2011

Arenaviruses form a noncytolytic infection in their rodent hosts, yet can elicit severe hemorrhagic disease in humans. How arenaviruses regulate gene expression remains unclear, and further understanding may provide insight into the dichotomy of these disparate infection processes. Here we reconstitute arenavirus RNA synthesis initiation and gene expression regulation in vitro using purified components and demonstrate a direct role of the viral Z protein in controlling RNA synthesis. Our data reveal that Z forms a species-specific complex with the viral polymerase (L) and inhibits RNA synthesis initiation by impairing L catalytic activity. This Z–L complex locks the viral polymerase in a promoter-bound, catalytically inactive state and may additionally ensure polymerase packaging during virion maturation. Z modulates host factors involved in cellular translation, proliferation, and antiviral signaling. Our data defines an additional role in governing viral RNA synthesis, revealing Z as the center of a network of host and viral connections that regulates viral gene expression.
Global human mandibular variation reflects differences in agricultural and hunter-gatherer subsistence strategies
Authors: von Cramon-Taubadel Noreen
Published: November 2011

Variation in the masticatory behavior of hunter-gatherer and agricultural populations is hypothesized to be one of the major forces affecting the form of the human mandible. However, this has yet to be analyzed at a global level. Here, the relationship between global mandibular shape variation and subsistence economy is tested, while controlling for the potentially confounding effects of shared population history, geography, and climate. The results demonstrate that the mandible, in contrast to the cranium, significantly reflects subsistence strategy rather than neutral genetic patterns, with hunter-gatherers having consistently longer and narrower mandibles than agriculturalists. These results support notions that a decrease in masticatory stress among agriculturalists causes the mandible to grow and develop differently. This developmental argument also explains why there is often a mismatch between the size of the lower face and the dentition, which, in turn, leads to increased prevalence of dental crowding and malocclusions in modern postindustrial populations. Therefore, these results have important implications for our understanding of human masticatory adaptation.
Alternative perspective on the control of transpiration by radiation
Authors: Mott Keith A. , Peak David
Published: November 2011

Stomatal responses to light are important determinants for plant water use efficiency and for general circulation models, but a mechanistic understanding of these responses remains elusive. A recent study [Pieruschka R, Huber G, Berry JA (2010)
Proc Natl Acad Sci USA
107:13372–13377] concluded that stomata respond to total absorbed radiation rather than red and blue light as previously thought. We tested this idea by reexamining stomatal responses to red and blue light and to IR radiation. We show that responses to red and blue light are not consistent with a response to total absorbed radiation and that apparent stomatal responses to IR radiation are explainable as experimental artifacts. In addition, our data and analysis provide a method for accurately determining the internal temperature of a leaf.
Sphingomyelin and sphingomyelin synthase (SMS) in the malignant transformation of glioma cells and in 2-hydroxyoleic acid therapy
Authors: Barceló-Coblijn Gwendolyn , Martin Maria Laura , de Almeida Rodrigo F. M. , Noguera-Salvà Maria Antònia , Marcilla-Etxenike Amaia , Guardiola-Serrano Francisca , Lüth Anja , Kleuser Burhard , Halver John E. , Escribá Pablo V.
Published: November 2011

The mechanism of action of 2-hydroxyoleic acid (2OHOA), a potent antitumor compound, has not yet been fully elucidated. Here, we show that human cancer cells have markedly lower levels of sphingomyelin (SM) than nontumor (MRC-5) cells. In this context, 2OHOA treatment strongly augments SM mass (4.6-fold), restoring the levels found in MRC-5 cells, while a loss of phosphatidylethanolamine and phosphatidylcholine is observed (57 and 30%, respectively). The increased SM mass was due to a rapid and highly specific activation of SM synthases (SMS). This effect appeared to be specific against cancer cells as it did not affect nontumor MRC-5 cells. Therefore, low SM levels are associated with the tumorigenic transformation that produces cancer cells. SM accumulation occurred at the plasma membrane and caused an increase in membrane global order and lipid raft packing in model membranes. These modifications would account for the observed alteration by 2OHOA in the localization of proteins involved in cell apoptosis (Fas receptor) or differentiation (Ras). Importantly, SMS inhibition by D609 diminished 2OHOA effect on cell cycle. Therefore, we propose that the regulation of SMS activity in tumor cells is a critical upstream event in 2OHOA antitumor mechanism, which also explains its specificity for cancer cells, its potency, and the lack of undesired side effects. Finally, the specific activation of SMS explains the ability of this compound to trigger cell cycle arrest, cell differentiation, and autophagy or apoptosis in cancer cells.
Evolution of a modular software network
Authors: Fortuna Miguel A. , Bonachela Juan A. , Levin Simon A.
Published: November 2011

“Evolution behaves like a tinkerer” (François Jacob,
Science
, 1977). Software systems provide a singular opportunity to understand biological processes using concepts from network theory. The Debian GNU/Linux operating system allows us to explore the evolution of a complex network in a unique way. The modular design detected during its growth is based on the reuse of existing code in order to minimize costs during programming. The increase of modularity experienced by the system over time has not counterbalanced the increase in incompatibilities between software packages within modules. This negative effect is far from being a failure of design. A random process of package installation shows that the higher the modularity, the larger the fraction of packages working properly in a local computer. The decrease in the relative number of conflicts between packages from different modules avoids a failure in the functionality of one package spreading throughout the entire system. Some potential analogies with the evolutionary and ecological processes determining the structure of ecological networks of interacting species are discussed.
Common variant near the endothelin receptor type A (
EDNRA
) gene is associated with intracranial aneurysm risk
Authors: Yasuno Katsuhito , Bakırcıoğlu Mehmet , Low Siew-Kee , Bilgüvar Kaya , Gaál Emília , Ruigrok Ynte M. , Niemelä Mika , Hata Akira , Bijlenga Philippe , Kasuya Hidetoshi , Jääskeläinen Juha E. , Krex Dietmar , Auburger Georg , Simon Matthias , Krischek Boris , Ozturk Ali K. , Mane Shrikant , Rinkel Gabriel J. E. , Steinmetz Helmuth , Hernesniemi Juha , Schaller Karl , Zembutsu Hitoshi , Inoue Ituro , Palotie Aarno , Cambien François , Nakamura Yusuke , Lifton Richard P. , Günel Murat
Published: November 2011

The pathogenesis of intracranial aneurysm (IA) formation and rupture is complex, with significant contribution from genetic factors. We previously reported genome-wide association studies based on European discovery and Japanese replication cohorts of 5,891 cases and 14,181 controls that identified five disease-related loci. These studies were based on testing replication of genomic regions that contained SNPs with posterior probability of association (PPA) greater than 0.5 in the discovery cohort. To identify additional IA risk loci, we pursued 14 loci with PPAs in the discovery cohort between 0.1 and 0.5. Twenty-five SNPs from these loci were genotyped using two independent Japanese cohorts, and the results from discovery and replication cohorts were combined by meta-analysis. The results demonstrated significant association of IA with rs6841581 on chromosome 4q31.23, immediately 5′ of the
endothelin receptor type A
with
P
= 2.2 × 10
−8
[odds ratio (OR) = 1.22, PPA = 0.986]. We also observed substantially increased evidence of association for two other regions on chromosomes 12q22 (OR = 1.16,
P
= 1.1 × 10
−7
, PPA = 0.934) and 20p12.1 (OR = 1.20,
P
= 6.9 × 10
−7
, PPA = 0.728). Although endothelin signaling has been hypothesized to play a role in various cardiovascular disorders for over two decades, our results are unique in providing genetic evidence for a significant association with IA and suggest that manipulation of the endothelin pathway may have important implications for the prevention and treatment of IA.
100 years of Rous sarcoma virus
Authors: Weiss Robin A. , Vogt Peter K.
Published: November 2011

The discovery of Rous sarcoma virus, which was reported by Peyton Rous in the Journal of Experimental Medicine 100 years ago, opened the field of tumor virology. It showed that some cancers have infectious etiology, led to the discovery of oncogenes, and laid the foundation for the molecular mechanisms of carcinogenesis. Rous spent his entire research career at The Rockefeller Institute, and he was the JEM’s longest serving editor. Here, we comment briefly on the life of this remarkable scientist and on the importance of his discoveries.
Learning vaccinology from viral infections
Authors: Ahmed Rafi , Pulendran Bali
Published: November 2011

This issue of the Journal of Experimental Medicine celebrates and honors the life of Ralph Steinman (1943–2011), winner of the 2011 Nobel Prize in Physiology or Medicine. Ralph’s science was rooted in fundamental discovery with the goal of translating these findings into clinical medicine. He recognized the power of immunology in treating human disease and passionately championed studies on vaccine design, immune therapy, and human immunology. One particular collaborative effort between the Steinman and Sekaly laboratories resulted in a paper published in this issue of the journal.
On decomposable rational maps
Authors: Cabrera Carlos , Makienko Peter
Published: November 2011

If

R
R

is a rational map, the main result is a uniformization theorem for the space of decompositions of the iterates of

R
R

. Secondly, we show that Fatou conjecture holds for decomposable rational maps.