bluuebunny/crossref_metadata_2025 huggingface dataset:
Infrared spectra and quantum chemical calculations of the uranium-carbon molecules UC, CUC, UCH, and U(CC)2
Authors: Wang Xuefeng , Andrews Lester , Ma Dongxia , Gagliardi Laura , Gonçalves António P. , Pereira Cláudia C. L. , Marçalo Joaquim , Godart Claude , Villeroy Benjamin
Published: June 2011

Laser evaporation of carbon rich uranium/carbon alloy targets into condensing argon or neon matrix samples gives weak infrared absorptions that increase on annealing, which can be assigned to new uranium carbon bearing species. New bands at 827.6 cm−1 in solid argon or 871.7 cm−1 in neon become doublets with mixed carbon 12 and 13 isotopes and exhibit the 1.0381 carbon isotopic frequency ratio for the UC diatomic molecule. Another new band at 891.4 cm−1 in argon gives a three-band mixed isotopic spectrum with the 1.0366 carbon isotopic frequency ratio, which is characteristic of the anti-symmetric stretching vibration of a linear CUC molecule. No evidence was found for the lower energy cyclic U(CC) isomer. Other bands at 798.6 and 544.0 cm−1 are identified as UCH, which has a uranium-carbon triple bond similar to that in UC. Evidence is found for bicyclic U(CC)2 and tricyclic U(CC)3. This work shows that U and C atoms react spontaneously to form the uranium carbide U≡C and C≡U≡C molecules with uranium-carbon triple bonds.
Preparation of tips coated with poly(dimethylsiloxane) for scanning tunneling microscopy in aqueous solutions
Authors: Kuroda Mizuki , Nishino Tomoaki
Published: June 2011

A simple and reliable method for preparing tips coated with poly(dimethylsiloxane) (PDMS) for scanning tunneling microscopy (STM) in aqueous solutions is reported. Au STM tips were dip-coated with PDMS and subsequently cured. The coated tips were characterized by scanning electron microscopy, energy dispersive x-ray spectroscopy, and voltammetry. We show that the PDMS layer smoothly covers the tip surface except for its very apex. These tips enable atomically resolved imaging of a sample surface and measurement of single-molecule conductance below 1.0 nS with STM in aqueous solutions. Because of the superior compatibility of PDMS with organic solvents, the PDMS-coated tips would be useful for preparing molecular tips via their chemical modification in such solvents, enabling chemically selective imaging of a single molecule in water.
Ultrasoft primitive model of polyionic solutions: Structure, aggregation, and dynamics
Authors: Coslovich Daniele , Hansen Jean-Pierre , Kahl Gerhard
Published: July 2011

We introduce an ultrasoft core model of interpenetrating polycations and polyanions, with continuous Gaussian charge distributions, to investigate polyelectrolyte aggregation in dilute and semi-dilute salt-free solutions. The model is studied by a combination of approximate theories (random phase approximation and hypernetted chain theory) and numerical simulations. The calculated pair structure, thermodynamics, phase diagram, and polyion dynamics of the symmetric version of the model (the “ultrasoft restricted primitive model” or UPRM) differ from the corresponding properties of the widely studied “restricted primitive model” (RPM) where ions have hard cores. At sufficiently low temperatures and densities, oppositely charged polyions form weakly interacting, polarizable neutral pairs. The clustering probabilities, dielectric behavior, and electrical conductivity point to a line of sharp conductor-insulator transitions in the density-temperature plane. At very low temperatures, the conductor-insulator transition line terminates near the top of a first order coexistence curve separating a high-density liquid phase from a low-density vapor phase. The simulation data hint at a tricritical behavior, reminiscent of that observed for the two-dimensional Coulomb gas, which contrasts with the Ising criticality of its three-dimensional counterpart, the RPM.
Electromagnetic solitons in fully relativistic electron-positron plasmas with finite temperature
Authors: Lee Nam C.
Published: July 2011

The existence of localized structure of electromagnetic waves in relativistic electron-positron plasmas is investigated based on the pseudo-potential theory, without making any assumptions on the magnitudes of the flow velocity and temperature of the medium. The conditions for the localization of electromagnetic wave in the form of dark (dip type) soliton are found. In the small amplitude approximation, it is found that the dip becomes deeper and narrower as the temperature is raised. In low temperature T ≪ mc2, localized solution exists only if the equilibrium longitudinal fluid velocity (parallel to the direction of propagation) in the wave frame is larger than the classical thermal velocity T/m of the plasma. For ultra-relativistically high temperature T >> mc2, it is shown that dark soliton can exist if the equilibrium longitudinal velocity is larger than c/3.
Side wall effects in thin gravity-driven film flow – steady and draining flow
Authors: Haas A. , Pollak T. , Aksel N.
Published: July 2011

The increasing demand for thinner films in scientific and technological applications requires a better knowledge of the effect of side walls on such flows, especially as far as the formation of a capillary boundary layer is concerned. In this paper gravity-driven thin film flow in an open channel is investigated, highlighting the competing effects of the no-slip condition and velocity overshoot due to capillary elevation at the bounding side walls. Their influence on the flow rate, the velocity field, the Reynolds number, and the free surface shape is studied for two flow types: (i) the case with vanishingly small capillary elevation at the side walls compared to the film thickness at the center of the channel; (ii) the situation when capillary elevation at the side walls dominates over the film thickness at the center of the channel. For both, large deviations from the two-dimensional reference system occur. The theoretical predictions are compared to experimental observations, for the case of side walls with different wetting properties defined in terms of the static contact angle there.
Note: Perturbation theory of polymer chains revisited. I. Corrected C1 and C2 parameters for excluded volume chains
Authors: Zifferer Gerhard , Olaj Oskar Friedrich
Published: June 2011

Random walks (RWs) and self-avoiding random walks (SAWs) embedded in the cubic lattice are evaluated with respect to the number of i-tuples of overlaps within incompatible pairs leading to the parameters Ck of the perturbation theory of the excluded volume u. These parameters are strongly dependent on chain length N never before realized by theory. Extrapolated to infinite chain length C1 and C2 are fairly well recovered for RWs while markedly larger values appear for SAWs. The Kurata-Yamakawa approach recovers the simulation results with high accuracy if self-consistent C1 and C2 values are applied thus representing an easy to use well-performing method for the prediction of u in athermal solution.
The self-consistent nonlinear theory of electron cyclotron maser based on anomalous Doppler effect
Authors: Kong Ling-Bao , Hou Zhi-Ling , Xie Chao-Ran
Published: June 2011

The self-consistent nonlinear equations, which describe electron cyclotron maser under the condition of anomalous Doppler effect, have been developed. By employing an initially rectilinear electron beam and a guiding static magnetic field, an efficient energy transfer between electrons and microwave can be achieved. The results suggest potential applications in designing a compact and efficient microwave generation/amplification device.
Modification of vibrational damping times in thin gold films by self-assembled molecular layers
Authors: Hettich M. , Bruchhausen A. , Riedel S. , Geldhauser T. , Verleger S. , Issenmann D. , Ristow O. , Chauhan R. , Dual J. , Erbe A. , Scheer E. , Leiderer P. , Dekorsy T.
Published: June 2011

The mechanical contact between a thin gold film and a silicon substrate is investigated by ultrafast pump-probe spectroscopy providing quantitative values on the damping time of coherent longitudinal vibrations of the gold film. A distinct increase in damping times is observed when a self-assembled molecular layer is introduced between the gold film and the substrate. We deduce the frequency dependence of the damping times by varying the thickness of the gold films. Experimental results are compared to numerical simulations based on a visco-elastic model and the acoustic mismatch model.
Formation of a semi-insulating layer in n-type 4H-SiC by electron irradiation
Authors: Kaneko Hiromi , Kimoto Tsunenobu
Published: June 2011

Electron irradiation has been applied to the formation of a semi-insulating 4H-SiC(0001) layer. The resistivity of the semi-insulating layer, which was irradiated with a fluence of 1.9 × 1018 cm−2 at 400 keV, exceeded 1010 Ω cm at room temperature. From capacitance-voltage characteristics of Schottky structure, the depth of the semi-insulating layer was estimated to be 10 μm, indicating that the whole region of lightly-doped n-type epilayer was converted to the semi-insulating layer by electron irradiation. The semi-insulating property can be ascribed to electron trapping at the Z1/2 and EH6/7 centers generated by electron irradiation. The threshold energy for the generation of Z1/2 center was about 100 keV.
Kinetic enhancement in nanoscale electrochemical systems caused by non-normal distributions of the electrode potential
Authors: García-Morales Vladimir , Krischer Katharina
Published: June 2011

We have recently shown [Proc. Natl. Acad. Sci. U.S.A. 107, 4528 (2010)] that the discreteness and stochasticity of an electron transfer event on a resistively coupled nanoelectrode causes mesoscopic fluctuations in time of the electrode potential. These fluctuations give rise to a time-average faradaic current density substantially larger than in the macroscopic limit. The deviations result to a large extent from the potentiostatic control, which imposes a constraint on the evolution of the electrode potential that leads to non-normal distributions. The degree of freedom of the electrode potential requires a resistance between nanoelectrode and metallic support. In this article, we study the dependence of the mesoscopic stochastic dynamics on this resistance (assumed to be ohmic). We show that the enhancement of the reaction rate vanishes in both limits, zero and infinite resistance. The distribution of the electrode potential continuously transforms from a normal distribution at infinite resistance (the galvanostatic limit), through a more and more peaked distribution with increasingly important rare events to the deterministic behavior at zero resistance.
Study of magneto-electroluminescence and magneto-conductance in polymer light-emitting electrochemical cells
Authors: Ni G. , Nguyen T. D. , Vardeny Z. V.
Published: June 2011

Magneto-electroluminescence (MEL) and magneto-conductance (MC) have been investigated in polymer light-emitting electrochemical cells based on “super-yellow” poly-(phenylene vynilene) (SY-PPV). We measured positive MEL(B) and MC(B) responses that show a modified Lorentzian shape for B < 120 mT. At B < 2 mT, both MEL(B) and MC(B) responses show a second component, opposite in sign to the higher field response. We interpret the magnetic field response using the polaron pair model, from which we extract the hyperfine interaction constant of polarons in the SY-PPV polymer.
Effect of misfit dislocations on luminescence in m-plane InGaN quantum wells
Authors: Huang Y. , Sun K. W. , Fischer A. M. , Wei Q. Y. , Juday R. , Ponce F. A. , Kato R. , Yokogawa T.
Published: June 2011

A correlation has been established between the optical and structural properties of blue-light-emitting diode structures grown on free-standing m-plane GaN. A double-peak InGaN quantum well emission at room temperature has been observed with a strong inhomogeneous spatial distribution, which can be associated with the presence of dislocations originating at the InGaN layers. It is argued that the difference in peak energy positions is due to in-plane piezoelectric fields within the dislocated regions.
Polymer stabilized chiral nematic liquid crystals for fast switching and high contrast electro-optic devices
Authors: Gardiner Damian J. , Morris Stephen M. , Castles Flynn , Qasim Malik M. , Kim Wook-Sung , Choi Su Seok , Park Hyun-Jin , Chung In-Jae , Coles Harry J.
Published: June 2011

A fast switching electro-optic device, based upon the in-plane addressing of very short pitch polymer stabilized chiral nematic liquid crystals, is presented. Polymer stabilization of the standing helical arrangement is essential to prevent the appearance of defects above the in-plane electrodes. Response times as short as 50 μs are observed at room temperature along with contrast ratios greater than 3000:1 owing to the high optical extinction at visible wavelengths in the “Off” state. The combination of these fast response times with such high contrast ratios is of great importance for next generation electro-optical elements.
Comment on “Discussion on a mechanical equilibrium condition of a sessile drop on a smooth solid surface” [J. Chem. Phys. 130, 144106 (2009)]
Authors: Ghasemi H. , Ward C. A.
Published: June 2011

Two articles have recently appeared that question the validity of the Young equation. The authors propose to add a new term, but their derivation is based on two mathematical errors, and they neglect gravity, mass transport at the interface and adsorption effects. Thus, the model they propose cannot account for the experimentally observed dependence of a sessile-droplet-contact angle on three-phase line curvature and on the pressure in the liquid phase at the three-phase line.
Composition pulling effect and strain relief mechanism in AlGaN/AlN distributed Bragg reflectors
Authors: Liu B. , Zhang R. , Zheng J. G. , Ji X. L. , Fu D. Y. , Xie Z. L. , Chen D. J. , Chen P. , Jiang R. L. , Zheng Y. D.
Published: June 2011

We report on the composition pulling effect and strain relief mechanism in AlGaN/AlN distributed Bragg reflectors (DBRs) grown on GaN template/α-Al2O3(0001) by metal organic chemical vapor deposition. The reciprocal space mapping contours reveal that these DBRs are coherently grown. Cross-section transmission electron microscopy image of the AlGaN/AlN DBRs and the energy-dispersive x-ray analysis indicate that an AlGaN layer with gradient Al composition is located between the Al0.4Ga0.6N and AlN layers along the [0001] direction. It is attributed to the fact that Ga atoms in AlGaN are pulled and segregated to the upper layer by the strain. The density of strain energy is estimated to reduce more than one order by forming this quasi-three-sublayer structure comparing to the designed bi-sublayer structure.
Raman study of strained Ge1−xSnx alloys
Authors: Lin Hai , Chen Robert , Huo Yijie , Kamins Theodore I. , Harris James S.
Published: June 2011

The Ge-Ge longitudinal optical Raman peak has been measured in strained Ge1−xSnx alloy layers grown on top of relaxed InyGa1−yAs buffer layers on GaAs substrates by molecular beam epitaxy. The experimental result shows that the peak frequency shift increases linearly from the value for bulk Ge with the Sn fraction x and the strain ɛ, Δω = ω − ωGe = ax + bɛ. In these experiments alloy and strain contributions are decoupled and measured separately, and a and b are determined to be a = − 82 ± 4 cm−1 and b = − 563 ± 34 cm−1, over the entire composition and strain range investigated.
Thermal lens spectrometry: Optimizing amplitude and shortening the transient time
Authors: Silva Rubens , de Araújo Marcos A. C. , Jali Pedro , Moreira Sanclayton G. C. , Alcantara Petrus , de Oliveira Paulo C.
Published: June 2011

Based on a model introduced by Shen et al. for cw laser induced mode-mismatched dual-beam thermal lens spectrometry (TLS), we explore the parameters related with the geometry of the laser beams and the experimental apparatus that influence the amplitude and time evolution of the transient thermal lens (TL) signal. By keeping the sample cell at the minimum waist of the excitation beam, our results show that high amplitude TL signals, very close to the optimized value, combined with short transient times may be obtained by reducing the curvature radius of the probe beam and the distance between the sample cell and the detector. We also derive an expression for the thermal diffusivity which is independent of the excitation laser beam waist, considerably improving the accuracy of the measurements. The sample used in the experiments was oleic acid, which is present in most of the vegetable oils and is very transparent in the visible spectral range.
Induced Gamma-Band Activity and Fixational Eye Movements are Differentially Influenced by Low-and High-Level Factors in a Visual Object Classification Task
Authors: Martinovic J , Kosilo M , Wuerger S M , Hunt A R
Published: June 2011

Until recently induced high frequency oscillatory activity (gamma-band activity; >30 Hz) was considered a neural marker of cortical object representation. However, Yuval-Greenberg et al (2008; Neuron) demonstrated that induced gamma-band activity (GBA) in the elecetroencephalogram (EEG) is susceptible to artifacts caused by miniature eye movements, which account for the major part of the signal in the crucial time window of 200-400 ms after stimulus onset. Is there an underlying cortical-induced gamma-band response that is obscured by ocular artifacts but can still be recorded with EEG? Furthermore, if object-specific modulations of induced GBA in previous studies were caused by ocular artifacts, should we instead study fixational eye movements as a response that can reflect higher-level representational processes in vision? In order to investigate this, we conducted an eye tracking experiment and an EEG experiment using the same design. Participants were asked to classify line drawings of objects or non-objects. To introduce low-level differences, their contours were defined along different directions in cardinal colour space: 1) S-cone-isolating (S), or 2) intermediate isoluminant (S and L-M), or 3) a full-colour stimulus, containing an additional achromatic component (S; L-M; L+M+S). In both experiments, behavioural performance was optimal for full-colour stimuli. In the eye tracking experiment, fixational eye movement rates 200-400 ms after stimulus onset depended on low-level factors, with no difference between objects and non-objects. In the EEG experiment, miniature eye movements were identified and removed using the saccadic filter approach. The artifact-free induced GBA exhibited a lateralised distribution, with enhancements at left and right posterior sites. Activity was higher for full-colour objects on the left, with the opposite effect observed on the right. We conclude that induced GBA can be observed in the EEG. While it showed high-level object-specific modulations, miniature eye movements were driven solely by low-level information.
Visual Discomfort and Blur
Authors: O'Hare L , Hibbard P B
Published: June 2011

Natural images typically have an approximately 1/f amplitude spectrum. Images that have relatively high amplitude at low spatial frequencies in comparison with a 1/f spectrum have been found to be uncomfortable (Fernandez and Wilkins, 2008, Juricevic et al, 2010). Such images also tend to be perceived as more blurred (Webster et al, 2002, Murray and Bex, 2010). This suggests that the loss of high spatial frequency information might increase visual discomfort. This could be due to an effect on the accommodation response, which is influenced by the spatial frequency content of images (eg, Charman and Tucker, 1977). Stimuli with a relative increase in low spatial frequency information might be uncomfortable because they are a poor stimulus for accommodation. The current study investigates the relationship between perceived blur, visual discomfort, and relative amounts of high and low spatial frequency information using both simple “bull's eye target” stimuli and natural images. Loss of high spatial frequency information was found to increase both visual discomfort judgements and perceived blur in simple stimuli. Increasing blur (loss of high spatial frequency information through either sinc or Gaussian filtering) in natural images was also found to increase visual discomfort judgements. Loss of high spatial frequency information increases discomfort, and perceived blur, in both simple and complex images. These results suggest that discomfort arises in images that present a difficult stimulus for accommodation. It is important therefore to consider how stimuli are accommodated by the eye, as well how they are encoded by the visual cortex, in understanding visual discomfort.
IL-2R common γ-chain is epigenetically silenced by nucleophosphin–anaplastic lymphoma kinase (NPM-ALK) and acts as a tumor suppressor by targeting NPM-ALK
Authors: Zhang Qian , Wang Hong Yi , Liu Xiaobin , Bhutani Gauri , Kantekure Kanchan , Wasik Mariusz
Published: June 2011

Anaplastic lymphoma kinase (ALK), physiologically expressed only by certain neural cells, becomes highly oncogenic, when aberrantly expressed in nonneural tissues as a fusion protein with nucleophosphin (NPM) and other partners. The reason why NPM-ALK succeeds in transforming specifically CD4
+
T lymphocytes remains unknown. The IL-2R common γ-chain (IL-2Rγ) is shared by receptors for several cytokines that play key roles in the maturation and growth of normal CD4
+
T lymphocytes and other immune cells. We show that IL-2Rγ expression is inhibited in T-cell lymphoma cells expressing NPM-ALK kinase as a result of DNA methylation of the
IL-2Rγ
gene promoter. IL-2Rγ promoter methylation is induced in malignant T cells by NPM-ALK. NPM-ALK acts through STAT3, a transcription factor that binds to the
IL-2Rγ
gene promoter and enhances binding of DNA methyltransferases (DNMTs) to the promoter. In addition, STAT3 suppresses expression of miR-21, which selectively inhibits DNMT1 mRNA expression. Reconstitution of IL-2Rγ expression leads to loss of the NPM-ALK protein and, consequently, apoptotic cell death of the lymphoma cells. These results demonstrate that the oncogenic tyrosine kinase NPM-ALK induces epigenetic silencing of the
IL-2Rγ
gene and that IL-2Rγ acts as a tumor suppressor by reciprocally inhibiting expression of NPM-ALK.
Suppression of cytokine storm with a sphingosine analog provides protection against pathogenic influenza virus
Authors: Walsh Kevin B. , Teijaro John R. , Wilker Peter R. , Jatzek Anna , Fremgen Daniel M. , Das Subash C. , Watanabe Tokiko , Hatta Masato , Shinya Kyoko , Suresh Marulasiddappa , Kawaoka Yoshihiro , Rosen Hugh , Oldstone Michael B. A.
Published: June 2011

Human pandemic H1N1 2009 influenza virus rapidly infected millions worldwide and was associated with significant mortality. Antiviral drugs that inhibit influenza virus replication are the primary therapy used to diminish disease; however, there are two significant limitations to their effective use: (
i
) antiviral drugs exert selective pressure on the virus, resulting in the generation of more fit viral progeny that are resistant to treatment; and (
ii
) antiviral drugs do not directly inhibit immune-mediated pulmonary injury that is a significant component of disease. Here we show that dampening the host's immune response against influenza virus using an immunomodulatory drug, AAL-R, provides significant protection from mortality (82%) over that of the neuraminidase inhibitor oseltamivir alone (50%). AAL-R combined with oseltamivir provided maximum protection against a lethal challenge of influenza virus (96%). Mechanistically, AAL-R inhibits cellular and cytokine/chemokine responses to limit immunopathologic damage, while maintaining host control of virus replication. With cytokine storm playing a role in the pathogenesis of a wide assortment of viral, bacterial, and immunologic diseases, a therapeutic approach using sphingosine analogs is of particular interest.
Power of Peer Review: An Online Collaborative Learning Assignment in Social Psychology
Authors: Cathey Christie
Published: July 2011

In a semester-long, peer review assignment, undergraduates enrolled in a social psychology course wrote essays that applied course concepts to life experiences. Students anonymously posted essays for the entire class to view, and peers posted commentaries on classmates' essays using an online discussion board. Students rated the assignment as enjoyable and useful for improving their writing skills and conceptual understanding. For the instructor, the online nature of the assignment afforded all the benefits of peer review without increasing workload.
Use of Pre-and Postcourse Surveys to Predict Student Outcomes
Authors: Landrum R. Eric , Mulcock Stephen D.
Published: July 2011

We obtained data from pre-and postcourse questionnaires given in an Introduction to the Psychology Major course taught for 10 semesters and compared these data with institutional outcomes concerning the students' last known major and their graduation status. We found the questionnaire reliably measured (a) vocational identity, (b) knowledge of course content, and (c) students' knowledge of information-finding strategies. Generally, students who entered the course with high commitment to psychology or who demonstrated the greatest growth in commitment tended to remain psychology majors and earned the bachelor's degree in psychology. We discuss factors that affect these predictive outcomes.
Keeping it Short and Sweet: Brief, Ungraded Writing Assignments Facilitate Learning
Authors: Drabick Deborah A. G. , Weisberg Robert , Paul Luci , Bubier Jennifer L.
Published: July 2011

Can short, ungraded, free-writing assignments promote learning of course material? We randomly assigned introductory psychology recitation sections (N = 978 students) to writing or thinking conditions. For all sections, teaching assistants presented students with a discussion topic based in current coursework. Students either wrote or thought about the topic for 5 min. All sections then discussed the topic for approximately 10 min. Exams included questions related to the discussion topics. Students in the writing condition attended class more often and performed better on factual and conceptual multiple-choice exam questions than students in the thinking condition, even after controlling for measures of student quality. The results suggested that brief free writing improved factual and conceptual learning.
Looking Good, Teaching Well? Linking Liking, Looks, and Learning
Authors: Gurung Regan A. R. , Vespia Kristin M.
Published: July 2011

Does the appearance of an instructor and the format of the class influence student grades and learning? We tested this question with 861 undergraduate students who completed an online questionnaire rating their instructors. Students were equally spread across class year and were from different majors. We used multiple regression analyses and found that likable, good-looking, well-dressed, and approachable teachers had students who said they learned more, had higher grades, and liked the class better.
Presentation Software in the College Classroom: Don't Forget the Instructor
Authors: Hardin Erin E.
Published: July 2011

Past research on the effects of presentation software has relied on small samples and experienced instructors. My research used a quasi-experimental pretest–posttest design to evaluate the impact of PowerPoint® on student learning, satisfaction, and engagement in an introductory psychology course taught by graduate student instructors. Results showed several main effects of instructor but virtually no effects of PowerPoint, although there was a significant instructor by PowerPoint interaction on perceived learning and interest in psychology. PowerPoint reduced perceived learning for one instructor, but increased interest in psychology for another. The results are a reminder that good teaching depends more on the instructor than the technology.
A Quantified Description of the Coupling between the Reaching Direction and Elbow Axis Direction
Authors: Stanišić M. M. , Goehler C. M. , Tomšič M.
Published: July 2011

The human body continues to be an inspiration for the work of a myriad of different fields, both scientific and mathematic. In particular, robotics draws upon the motions and relationships of different human systems in order to reproduce similar mobility while performing different tasks. The human shoulder–arm–elbow complex has been one of the most difficult to exactly replicate. This paper examines the relationship between the motion of the shoulder while positioning the center of the wrist during voluntary arm movements and the resulting orientation of the arm, in particular the direction of the axis passing through the elbow joint. Experimental data is presented that was used to quantify this coupling between the reaching direction of the arm and the elbow axis direction. The results from this paper are two surface‐fit equations that can be used to determine the elbow axis direction when given the location of the wrist center. These results are useful when considering the design and control of shoulder–arm–elbow complex models.
Toward Low‐Cost Highly Portable Tactile Displays with Shape Memory Alloys
Authors: Velázquez R. , Pissaloux E. E. , Hafez M. , Szewczyk J.
Published: July 2011

This paper presents a new concept of low‐cost, high‐resolution, lightweight, compact and highly portable tactile display. The prototype consists of an array of 8 × 8 upward/downward independent moveable pins based on shape memory alloy (SMA) technology. Each tactile actuator consists of an antagonist arranged pair of miniature NiTi SMA helical springs capable of developing a 300 mN pull force at 1.5 Hz bandwidth by using simple forced‐air convection. The proposed concept allows the development of 200 g weight tactile instruments of compact dimensions which can be easily carried by a visually disabled user. A detailed technical description of the SMA active element, tactile actuator and tactile display is presented and discussed. Preliminary perceptual results confirm the effectiveness of the display on information transmission.
A Collision‐Free Path‐Planning Method for an Articulated Mobile Robot
Authors: Quintero-Alvarez P. , Ramirez G. , Zeghloul S.
Published: July 2011

In previous works, we treated the collision‐free path‐planning problem for a nonholonomic mobile robot in a cluttered environment. We used a method based on a representation of the obstacles on the robot′s velocity space. This representation is called Feasible Velocities Polygon (FVP). Every obstacle in the robot′s influence zone is represented by a linear constraint on the robot′s velocities such that a collision between the robot and the obstacle could be avoided. These constraints define a convex subset in the velocity space, the FVP. Every velocity vector in the FVP ensures a safe motion for the given obstacle configuration. The path‐planning problem is solved by an optimization approach between the FVP and a reference velocity to reach the goal. In this paper, we have extended our work to an articulated mobile robot evolving in a cluttered environment. This robot is composed of a differential mobile robot and one or several modules that together form the trailer which are linked by off‐center joints. This kind of robot is a strongly constrained system. Even in a free environment, under some circumstances, the robot may be blocked by its trailers in its progression towards the goal. The proposed approach, compared to other methods, has the main advantage of integrating anti‐collision constraints between the articulated robot itself and the environment, in order to avoid and resolve dead‐lock situations. For moving to the final position, the articulated mobile robot uses the FVP and a reference control law, to formulate the constraints method as a problem of minimal distance calculation. This formulation is then solved with the algorithm of minimal distance calculation proposed by Zeghloul (Zeghloul and Rambeaud, 1996). When a dead‐locking situation arises and according to the robot–obstacle configuration, we have developed three different modules to solve these conditions. Each module uses a different approach to resolve the blocking situation. In order to show the capabilities of our method to lead the articulated robot to the final position in a stable way, a numerical result is presented.
Simple Mathematical and Computational Wear Model for Ultra‐High‐Molecular‐Weight Polyethylene Total Hip Replacements
Authors: Chan K. H. S. , Pearce T. , Blake R. W. , Chow L. , Wu S. , Wong F. , Li J.
Published: July 2011

Ultra‐high‐molecular‐weight polyethylene is an important constituent of hip implants. Surgical revisions are required because of implant loosening and osteolysis (destruction or resorption of bone tissue). We develop a mathematical and a computational model to determine implant life (defined as the time when 20% of the implants operating at a given wear rate is revised) based on wear rates and apply them to the data of Sochart (Clin Orthop Relat Res, 363:135–50, 1999). No significant difference was found between mathematical and computational model predictions (14.8 and 14.7 years, respectively) from the actual value of 15.0 ± 3.9 years ( ± 2SE; P > 0.05). We find that an increase in cross‐linking does not decrease implant life greatly. However, a large decrease in implant life occurs with an increase in surface roughness, cycles per year and body weight or a decrease in contact stress and femoral head radius.
Mirror Reversal: Empirical Tests of Competing Accounts
Authors: Takano Yohtaro , Tanaka Akihiro
Published: July 2011

In a mirror, left and right are said to look reversed. Surprisingly, this very familiar phenomenon, mirror reversal, has still no agreed-upon account to date. This study compared a variety of accounts in the light of empirical data. In Experiment 1, 102 students judged whether the mirror image of a person or a character looked reversed or not in 15 settings and also judged the directional relation between its components. In Experiment 2, 52 students made the reversal judgements in 13 settings. It was found for the first time that a substantial proportion of people denied the left–right mirror reversal of a person, whereas virtually all of them did recognize that of a character. This discrepancy strongly suggested that these two kinds of mirror reversal are produced by different processes, respectively. A number of findings including this discrepancy clearly contradicted two accounts that are currently active: the one based on the priority of the up–down and front–back axes over the left–right axis, and the one based on the physical rotation of an object. All the findings were consistent with an account that considered mirror reversal a complex of three different phenomena produced by three different processes, respectively.
Observations of core toroidal rotation reversals in Alcator C-Mod ohmic L-mode plasmas
Authors: Rice J.E. , Duval B.P. , Reinke M.L. , Podpaly Y.A. , Bortolon A. , Churchill R.M. , Cziegler I. , Diamond P.H. , Dominguez A. , Ennever P.C. , Fiore C.L. , Granetz R.S. , Greenwald M.J. , Hubbard A.E. , Hughes J.W. , Irby J.H. , Ma Y. , Marmar E.S. , McDermott R.M. , Porkolab M. , Tsujii N. , Wolfe S.M.
Published: June 2011

Direction reversals of intrinsic toroidal rotation have been observed in Alcator C-Mod ohmic L-mode plasmas following modest electron density or toroidal magnetic field ramps. The reversal process occurs in the plasma interior, inside of the q = 3/2 surface. For low density plasmas, the rotation is in the co-current direction, and can reverse to the counter-current direction following an increase in the electron density above a certain threshold. Reversals from the co- to counter-current direction are correlated with a sharp decrease in density fluctuations with k

R
⩾ 2 cm−1 and with frequencies above 70 kHz. The density at which the rotation reverses increases linearly with plasma current, and decreases with increasing magnetic field. There is a strong correlation between the reversal density and the density at which the global ohmic L-mode energy confinement changes from the linear to the saturated regime.
Power requirements for superior H-mode confinement on Alcator C-Mod: experiments in support of ITER
Authors: Hughes J.W. , Loarte A. , Reinke M.L. , Terry J.L. , Brunner D. , Greenwald M. , Hubbard A.E. , LaBombard B. , Lipschultz B. , Ma Y. , Wolfe S. , Wukitch S.J.
Published: June 2011

Power requirements for maintaining sufficiently high confinement (i.e. normalized energy confinement time H
98 ⩾ 1) in H-mode and its relation to H-mode threshold power scaling, P
th, are of critical importance to ITER. In order to better characterize these power requirements, recent experiments on the Alcator C-Mod tokamak have investigated H-mode properties, including the edge pedestal and global confinement, over a range of input powers near and above P
th. In addition, we have examined the compatibility of impurity seeding with high performance operation, and the influence of plasma radiation and its spatial distribution on performance. Experiments were performed at 5.4 T at ITER relevant densities, utilizing bulk metal plasma facing surfaces and an ion cyclotron range of frequency waves for auxiliary heating. Input power was scanned both in stationary enhanced Dα (EDA) H-modes with no large edge localized modes (ELMs) and in ELMy H-modes in order to relate the resulting pedestal and confinement to the amount of power flowing into the scrape-off layer, P
net, and also to the divertor targets. In both EDA and ELMy H-mode, energy confinement is generally good, with H
98 near unity. As P
net is reduced to levels approaching that in L-mode, pedestal temperature diminishes significantly and normalized confinement time drops. By seeding with low-Z impurities, such as Ne and N2, high total radiated power fractions are possible, along with substantial reductions in divertor heat flux (>4×), all while maintaining H
98 ∼ 1. When the power radiated from the confined versus unconfined plasma is examined, pedestal and confinement properties are clearly seen to be an increasing function of P
net, helping to unify the results with those from unseeded H-modes. This provides increased confidence that the power flow across the separatrix is the correct physics basis for ITER extrapolation. The experiments show that P
net/P
th of one or greater is likely to lead to H
98 ⩾ 1 operation, and also that such a condition can be made compatible with a low-Z radiative impurity solution for reducing divertor heat loads to levels acceptable for ITER.
Using National Instruments LabVIEW™ Education Edition in schools
Authors: Butlin Chris A
Published: June 2011

With the development of LabVIEW™ Education Edition schools can now provide
experience of using this widely used software. Here, a few of the many applications
that students aged around 11 years and over could develop are outlined in the
resulting front panel screen displays and block diagrams showing the associated
graphical programmes, plus a couple which are more complex provided for direct
use.
Brain natriuretic peptide‐guided treatment does not improve morbidity and mortality in extensively treated patients with chronic heart failure: responders to treatment have a significantly better outcome
Authors: Karlström Patric , Alehagen Urban , Boman Kurt , Dahlström Ulf ,   on behalf of the UPSTEP‐study group
Published: June 2011

Aim

To determine whether brain natriuretic peptide (BNP)‐guided heart failure (HF) treatment improves morbidity and/or mortality when compared with conventional treatment.

Methods and results

UPSTEP was an investigator‐initiated, randomized, parallel group, multicentre study with a PROBE design. Symptomatic patients with worsening HF, New York Heart Association class II–IV, ejection fraction <40% and elevated BNP levels, were included. All patients (n= 279) were treated according to recommended guidelines and randomized to BNP‐guided (BNP) or to conventional (CTR) HF treatment. The goal was to reduce BNP levels to <150 ng/L in younger patients and <300 ng/L in elderly patients, respectively. The primary outcome was a composite of death due to any cause, need for hospitalization and worsening HF. The study groups were well matched, including for BNP concentration at entry (mean: 808 vs. 899 ng/L; P= 0.34). There were no significant differences between the groups regarding either the primary outcome (P = 0.18) or any of the secondary endpoints. There were no differences for the pre‐specified analyses; days out of hospital, and younger vs. elderly. A subgroup analysis comparing treatment responders (>30% decrease in baseline BNP value) vs. non‐responders found improved survival among responders (P< 0.0001 for the primary outcome), and all of the secondary endpoints were also improved.

Conclusions

Morbidity and mortality were not improved by HF treatment guided by BNP levels. However, BNP responders had a significantly better clinical outcome than non‐responders. Future research is needed to elucidate the responsible pathophysiological mechanisms in this sub‐population.
Rheumatoid Arthritis: An Update on Diagnosis and Management
Authors: Kangesan Babu
Published: July 2011

Rheumatoid arthritis (RA) is a destructive polyarthropathy characterized by synovial inflammation. It is often a debilitating illness with significant and irreversible joint damage occurring within the first few years, and around 40% of RA patients are registered disabled within 3 years. Recent developments in treatment, in particular with early use of disease-modifying antirheumatic drugs (DMARDs), have dramatically improved prognosis. This article overviews the presentation and subsequent management of RA in primary care.
Predictive Effect of Serial Serum Alanine Aminotransferase Levels on Spontaneous HBeAg Seroconversion in Chronic Genotype B and C HBV–Infected Children
Authors: Wu Jia‐Feng , Su Yu‐Ru , Chen Chen‐Hsin , Chen Huey‐Ling , Ni Yen‐Hsuan , Hsu Hong‐Yuan , Wang Jane‐Ling , Chang Mei‐Hwei
Published: June 2011

Objective:

The present study aimed to investigate the association between serial serum alanine aminotransferase (ALT) and spontaneous hepatitis B e antigen (HBeAg) seroconversion age in chronic hepatitis B virus (HBV)–infected children.

Patients and Methods:

One hundred four HBeAg‐positive chronic genotype B or C HBV–infected patients were included in this long‐term prospective cohort study (mean initial age 7.20 years). Serial serum ALT levels and HBV serology markers were measured every 6 to 12 months. The 104 subjects made a total of 2525 visits during the study period, and the majority (93.6%) of visits were within a 1‐year interval apart from previous visits. Cox proportional hazards model with time‐dependent covariates was used in the survival analysis of HBeAg in these subjects.

Results:

During the chronic course of HBV infection, the median remaining times to spontaneous HBeAg seroconversion were 8.35, 5.14, 4.25, 3.95, and 2.80 years after the ALT levels crossed 20, 30, 40, 60, and 150 IU/L, respectively. The incidence rate of spontaneous HBeAg seroconversion within 6 months when a subject entered the phase of ALT between 60 and 150 IU/L was 5.57 times that of the phase with ALT < 60 IU/L. The incidence rate of HBeAg seroconversion once ALT levels were above 150 IU/L was 9.87 times that of the phase of ALT < 60 IU/L.

Conclusions:

The ALT levels above 30 IU/L served as a cutoff of the inflammatory phase in chronic genotype B and C HBV–infected patients. Serial ALT levels in chronic HBV–infected subjects offer a predicted effect on the occurrence of spontaneous HBeAg seroconversion.
Removal of two high-mannose N-linked glycans on gp120 renders human immunodeficiency virus 1 largely resistant to the carbohydrate-binding agent griffithsin
Authors: Huang Xin , Jin Wei , Griffin George E. , Shattock Robin J. , Hu Qinxue
Published: June 2011

High-mannoseN-linked glycans recognized by carbohydrate-binding agents (CBAs) are potential targets for topical microbicides. To better understand the mechanisms by which CBAs inhibit human immunodeficiency virus (HIV)-1 infection at the molecular level, we systematically analysed the contribution of site-specific glycans to the anti-HIV activity of CBAs by site-directed mutagenesis. Our results demonstrate that a single deglycosylation at N295 or N448 in a range of primary and T-cell-line-adapted HIV-1 isolates resulted in marked resistance to griffithsin (GRFT) but maintained the sensitivity to cyanovirin (CV-N),Galanthus nivalisagglutinin (GNA) and a range of neutralizing antibodies. Unlike CV-N and GNA, the interaction between GRFT and gp120 appeared to be dependent on the specific trimeric ‘sugar tower’ including N295 and N448. This was further strengthened by the results of GRFT–Env binding experiments. Our study identifies GRFT-specific gp120 glycans and may provide information for the design of novel CBA antiviral strategies.
Expression profile and subcellular localization of Torque teno sus virus proteins
Authors: Martínez-Guinó Laura , Ballester Maria , Segalés Joaquim , Kekarainen Tuija
Published: June 2011

In the present study, the expression, generation and subcellular localization of Torque teno sus virus (TTSuV) proteins were characterized into two genetically distinct TTSuV species (TTSuV1 and TTSuV2). Following transfection of three TTSuV1 and TTSuV2 full-length ORF (ORF1, ORF2 and ORF3) expression constructs into porcine kidney cells, alternative splice variants encoding new TTSuV protein isoforms were identified for the first time. Proteins encoded from ORF1 and ORF3 were localized in the nucleoli of porcine kidney cells and that of ORF2 in the cytoplasm and nucleus excluding the nucleoli. The subcellular localization of the different protein isoforms was not only similar between distinct TTSuV species but also to the ones described in human Torque teno virus (TTV). Results of the present in vitro study were not based on full-length viral clones but suggested that alternative splicing strategy to generate TTSuV protein isoforms probably occurs in vivo. Obtained data provide new information on molecular biology of TTSuV and anelloviruses, which until now has been solely based on results obtained from human TTV.
Interspecies transmission of the canine influenza H3N2 virus to domestic cats in South Korea, 2010
Authors: Song D. S. , An D. J. , Moon H. J. , Yeom M. J. , Jeong H. Y. , Jeong W. S. , Park S. J. , Kim H. K. , Han S. Y. , Oh J. S. , Park B. K. , Kim J. K. , Poo H. , Webster R. G. , Jung K. , Kang B. K.
Published: June 2011

In the past 4 years, incidences of endemic or epidemic respiratory diseases associated with canine influenza H3N2 virus in Asian dogs have been reported in countries such as South Korea and China. Canine species were considered to be the new natural hosts for this virus. However, at the beginning of 2010, influenza-like respiratory signs, such as dyspnoea, were also observed among cats as well as in dogs in an animal shelter located in Seoul, South Korea. The affected cats showed 100 % morbidity and 40 % mortality. We were able to isolate a virus from a lung specimen of a dead cat, which had suffered from the respiratory disease, in embryonated-chicken eggs. The eight viral genes isolated were almost identical to those of the canine influenza H3N2 virus, suggesting interspecies transmission of canine influenza H3N2 virus to the cat. Moreover, three domestic cats infected with intranasal canine/Korea/GCVP01/07 (H3N2) all showed elevated rectal temperatures, nasal virus shedding and severe pulmonary lesions, such as suppurative bronchopneumonia. Our study shows, for the first time, that cats are susceptible to canine influenza H3N2 infection, suggesting that cats may play an intermediate host role in transmitting the H3N2 virus among feline and canine species, which could lead to the endemic establishment of the virus in companion animals. Such a scenario raises a public health concern, as the possibility of the emergence of new recombinant feline or canine influenza viruses in companion animals with the potential to act as a zoonotic infection cannot be excluded.