bluuebunny/crossref_metadata_2025 huggingface dataset:
Formulation of iron oxides by nanoparticles of poly-lactide- co-D-α-tocopherol-polyethylene glycol 1000 succinate biodegradable polymer for magnetic resonance imaging
Authors: Prashant Chandrasekharan , Dipak Maity , Chang-Tong Yang , Kai-Hsiang Chuang , Jun Ding , Si-Shen Feng
Published: April 2010

Iron oxide nanocrystals of superparamagnetic nature provide diverse applications, which are extended for assessing and treating diseases in humans. Such nanocrystals are usually coated with a hydrophilic layer which enhances the property of the particles in vivo. In the current study, we have used a novel amphiphilic copolymer, poly-lactide-co-D-α-tocopherol-polyethylene glycol 1000 succinate to encapsulate Iron oxide nanocrystals to form polymer nanospheres with high encapsulation efficiency; the magnetic study of the nanoparticles showed that the iron oxide nanocrystals retained their magnetic property with a slight loss in the magnetic saturation. The relaxivity study performed using magnetic resonance imaging (MRI) showed that such nanoparticles formulation of iron oxides are useful for T2 weighted imaging, which is thus of great potential for MRI with better imaging effects and less clinical side effects. The particles were tested for the contrast enhancement in an in vivo model.
Magnetic, electrical transport and structural investigations of orthorhombic perovskite Pr2MnFeO6
Authors: Ganeshraj C. , Mahato Rabindra Nath , Divyaa D. , Santhosh P. N.
Published: April 2010

Substituting Mn ions in PrMnO3 by 3d-transition metal Fe ions, the structural, magnetic and magnetotransport properties are modified due to change in tolerance factor. The compound has an orthorhombic structure with the space group Pbnm. The field cooled magnetization data with temperature indicates that the compound is ferromagnetic below ∼200 K. The variation in magnetization with applied magnetic field show a hysteresis behavior, which confirms the ferromagnetic nature. The remanent magnetization and coercive field of the compound, at 2 K, were found to be 0.6169μB/f.u. and 0.4291 T respectively. Mössbauer spectrum indicates that the Fe3+ ions are in high spin state. The temperature variation in electrical resistivity measurement shows the sample to be insulating in nature.
Synthesis and physical properties of FeSe1/2Te1/2 superconductor
Authors: Awana V. P. S. , Pal Anand , Vajpayee Arpita , Mudgel Monika , Kishan H. , Husain Mushahid , Zeng R. , Yu S , Guo Y. F. , Shi Y. G. , Yamaura K. , Takayama-Muromachi E.
Published: April 2010

One of the most important properties of very recently reported FeSe based superconductors is the robustness of their superconductivity under applied magnetic field. The synthesis and control of superconductivity in FeSe based compounds is rather a difficult task. Synthesis and physical property characterization for optimized superconductivity of FeSe1/2Te1/2 at 13 K is reported here. The compound crystallized in a tetragonal structure with lattice parameters a=3.8015(2) and c=6.0280(4) Å. Magnetization measurements indicated bulk superconductivity with lower critical field (Hc1) of around 180 Oe. By applying Ginzburg–Landau theory, the Hc2(0) value is estimated to be ∼1840 kOe for the 90% of resistive transition. A heat capacity measurement revealed bulk superconductivity by a hump at Tc near 13 K and an expected decrease in the same was observed under an applied magnetic field.
Special pinning phenomena in superconductors with regular composite pinning arrays
Authors: Cao R , Horng Lance , Yang T. J. , Wu T. C. , Wang J. C. , Wu J. C.
Published: April 2010

Superconducting films with composite pinning sites are made with electron-beam lithography and reaction dry etching techniques. The composite pinning array consists of large pinning sites and small pinning sites. The large pinning sites are positioned on a honeycomb grid and the small pinning sites are positioned at the center of every hexagonal cell formed by the large pinning sites. Magnetotransport measurements are carried out by a four-probe technique. Special critical currents matching peaks are observed for this film at different temperatures. The positions and structures of the matching peaks seem irregular and are very different from the structures of the matching peaks for previously explored films, such as films with triangular, square, or honeycomb pinning arrays. By considering the multiple-vortex filling of different pinning sites, we could give a reasonable explanation to this interesting phenomenon.
Thickness and field dependent superconductivity in YBa2Cu3O7/La0.7Sr0.3MnO3 bilayers
Authors: Lin J. G. , Hsu Daniel , Song M. Y. , Chiang C. H. , Chan W. C.
Published: April 2010

Transport and magnetization properties of superconducting/ferromagnetic bilayers YBa2Cu3O7/La0.7Sr0.3MnO3 (YBCO/LSMO) are investigated with the thickness of bottom LSMO layer fixed at 50 nm and that of top YBCO (t) layer varied from 20 to 100 nm. Compared to bulk YBCO, the off set of superconducting temperature TSC-off is suppressed by 10 K for t=20 nm. The suppression rate of TSC versus magnetic field H is obtained as 1.2±0.2 K/T for all bilayers. Considering the polarization effect of LSMO on superconductivity is similar to the field effect, the internal field created by the LSMO in the YBCO(20nm)/LSMO(50nm) bilayer is estimated as 40 T.
A new criterion to distinguish the order of magnetic transitions by means of magnetic measurements
Authors: Bonilla Claudia Marcela , Bartolomé Fernando , García Luis Miguel , Parra-Borderías María , Herrero-Albillos Julia , Franco Victorino
Published: April 2010

A universal curve for the magnetic entropy change has been found to exist for a variety of materials with second order phase transitions. We have studied whether this universal behavior of the magnetocaloric effect is maintained in materials with first order phase transition, including RCo2 Laves phases and mixed La2/3(CaxSr1−x)1/3MnO3 manganites, which present both second order and first order magnetic ordering phase transitions. The rescaled magnetic entropy change curves for different applied fields collapse onto a single curve only for materials with second order phase transition. This universal curve may be used as a criterion for determining the order of magnetic phase transitions from purely magnetic measurements.
Magnetoresistivity and anisotropy along c-axis of ErNi2B2C
Authors: Lee W. C.
Published: April 2010

We have measured the c-axis magnetoresistivity ρc(H,T) of quaternary intermetallic compound ErNi2B2C for 2 K<T<300 K temperature region and 0 G<H<11 kG magnetic fields with H∥ab- and ∥c-axes, which has the Néel temperature TN (5.58 K for H=0) and superconducting transition temperature Tc (10.8 K for H=0). From these ρc(H,T)’s, the superconducting upper critical field HC2(T) curves were constructed for H∥ab and H∥c and its anisotropy in Hc2(T) is discussed and compared to the result from ab plane ρab(H,T) measurement considering magnetic pair breaking and the anisotropic field dependence of the Néel temperature arisen from the Er+3 sublattice.
Thermoelectric characterization by transient Harman method under nonideal contact and boundary conditions
Authors: Castillo Eduardo E. , Hapenciuc Claudiu L. , Borca-Tasciuc Theodorian
Published: April 2010

This work develops a strategy for thermoelectric characterization by transient Harman method under nonideal contact and boundary conditions. A thermoelectric transport model is presented that accounts for the effects of thermal and electrical contact resistances and heat transport through electrodes and supporting substrate. Parasitic effects play a large role in controlling the temperature difference across thin thermoelectric films on substrate. Analytical expressions for the temperature difference across the thermoelectric sample are provided to aid in the separate determination of the Seebeck coefficient, thermal conductivity, and electrical resistivity of the sample and to quantify the parasitic effects. The proposed experimental technique employs the Harman method under bipolar current excitation over a wide range of currents to allow Peltier only and combined Peltier and Joule heating effects to control the temperature difference across the sample. Proof of concept experiments were performed on commercial thermoelectric pellets mounted on the original ceramic substrate. In addition to the samples’ thermoelectric properties, thermal and electrical contact resistances could be also experimentally determined by this technique.
The extreme ultraviolet split and femtosecond delay unit at the plane grating monochromator beamline PG2 at FLASH
Authors: Sorgenfrei F. , Schlotter W. F. , Beeck T. , Nagasono M. , Gieschen S. , Meyer H. , Föhlisch A. , Beye M. , Wurth W.
Published: April 2010

An extreme ultraviolet split and femtosecond delay unit based on grazing incidence Mach–Zehnder geometry has been designed and implemented on the plane grating monochromator beamline PG2 at FLASH, the Free Electron Laser at DESY. This device splits the FLASH radiation into two beams, which can independently be steered, filtered and temporally delayed between −5.1 and +5.1 ps with uncertainty in the temporal accuracy of 210 as. To demonstrate the performance of this device, we have performed longitudinal coherence studies of FLASH radiation as well as measured the pulse length by nonlinear two-photon double-ionization in helium.
Design of a laser-assisted tomographic atom probe at Münster University
Authors: Schlesiger Ralf , Oberdorfer Christian , Würz Roland , Greiwe Gerd , Stender Patrick , Artmeier Michael , Pelka Patrick , Spaleck Frank , Schmitz Guido
Published: April 2010

To benefit from the latest technical improvements in atom probe analysis, a new tomographic atom probe has been built at the University of Münster, Germany. The instrument utilizes a femtosecond laser system with a high repetition rate combined with the ability of using a micrometer-sized extraction electrode and a wide angle configuration. Since field evaporation is triggered by laser pulses instead of high-voltage pulses, the instrument offers the ability to expand the range of analyzed materials to poorly conducting or insulating materials such as oxides, glasses, ceramics, and polymeric materials. The article describes the design of the instrument and presents characterizing measurements on metals, semiconductors, and oxide ceramic.
Sensitivity of nanotube chemical sensors at the onset of Poole–Frenkel conduction
Authors: Salehi-Khojin Amin , Field Christopher R. , Yeom Junghoon , Masel Richard I.
Published: April 2010

We find that the applied electric field has an unexpectedly large effect on the sensitivity of a sensor consisting of a network array of carbon nanotubes. The sensors are insensitive to gas adsorption at low applied voltages and remains low until a critical potential is reached. The sensor response then rapidly increases over a small range of voltage. The critical voltage roughly corresponds to the barrier for electron hopping between defect sites. These results show that there is a correlation between the conduction mechanism in the nanotube and the sensitivity of the nanotube. Such a correlation has not been observed previously.
Robust adaptive backstepping control of uncertain Lorenz system
Authors: Pishkenari Hossein Nejat , Jalili Nader , Mahboobi Seyed Hanif , Alasty Aria , Meghdari Ali
Published: April 2010

In this paper, a novel robust adaptive control method is proposed for controlling the Lorenz chaotic attractor. A new backstepping controller for the Lorenz system based on the Lyapunov stability theorem is proposed to overcome the singularity problem that appeared in using the typical backstepping control method. By exploiting the property of the system, the resulting controller is shown to be singularity free and the closed loop system is globally stable. Due to unavailability of system states measurement in practice, the controller is selected such that only one system state is needed. To overcome the problem of parameter uncertainty, an additional term to Lyapunov function is added and an identification scheme is adopted to have a negative definite Lyapunov function derivative. The simulation results demonstrate the effectiveness of the proposed controllers and approaches.
Evolution of the liquid-vapor coexistence of the hard-core Yukawa fluid as a function of the interaction range
Authors: El Mendoub E. B. , Wax J.-F. , Jakse N.
Published: April 2010

The present work is devoted to the study of the liquid-vapor coexistence curve of hard-core Yukawa fluids for range parameter λ, going from 0.5 to 7 by means of an integral equation approach. Both binodal and spinodal lines are computed and compared to available simulation data, and the integral equation used appears to be accurate. We also compare two methods for determining the coordinates of the critical point. The first one, using the rectilinear diameter law, appears to be less accurate than the second one based on the heat capacity at constant volume. It is found that the critical temperature decreases as the range of the interactions increases and that the liquid-vapor coexistence disappears for λ greater than 6.
Diminished cage effect in solid p-H2: Infrared spectra of ClSCS, ClCS, and ClSC in an irradiated p-H2 matrix containing Cl2 and CS2
Authors: Huang Chiung-Wei , Lee Yaw-Chang , Lee Yuan-Pern
Published: April 2010

Irradiation of a p-H2 matrix containing Cl2 and CS2 at 3.3 K with laser emission at 340 nm followed by annealing of the matrix produced main features at 1479.5 and 1480.8 cm−1. These lines are attributed to ν1 (SCS antisymmetric stretching) mode of ClSCS. Irradiation of the matrix at 355 nm decomposes ClSCS. Products CS (1272.2 and 1271.1 cm−1), ClCS (1193.9/1191.9 and 637.5 cm−1), and ClSC (1137.0 cm−1) were observed upon annealing. The assignments were based on comparison of observed vibrational wavenumbers and C13- and S34-isotopic ratios with those predicted with density-functional theories (B3LYP and BPW91/aug-cc-pVTZ). These results demonstrate that the cage effect of solid p-H2 is diminished so that isolated Cl was produced via photodissociation of Cl2 in situ and subsequently reacted with CS2 to form ClSCS, but not ClC(S)SCl, upon annealing; typically ClC(S)SCl was produced as the major product on irradiation of noble-gas matrices containing Cl2 and CS2. Observation of ClSCS but not ClCS2 is consistent with the theoretical prediction that only formation of the former proceeds via a barrierless path. Similarly, upon irradiation of ClSCS at 355 nm, Cl, CS, and CS2 were produced; subsequent annealing of the irradiated matrix produced ClSC and ClCS via barrierless paths.
Anomalous momentum transport and plasma heating in a collisionless return-current beam plasma system: Multifluid and kinetic approaches
Authors: Lee Kuang Wu , Büchner Jörg
Published: April 2010

The anomalous transport in a one-dimensional (1D), collisionless return-current beam plasma system is studied by means of electrostatic Vlasov and three-fluid simulations in a current-free counterstreaming electron beam situation. Despite of a lack of binary collisions in both approaches, the electron bulk drifts are found to slow down due to collisionless momentum transport and the electrons are heated. It is shown that in the multifluid plasma description, charge separation effects play a major role in this process. A 1D electrostatic Vlasov code simulation is performed with the same macroscopic plasma parameters to investigate the momentum transport mechanism if kinetic effects are taken into account. A comparison of the two different approaches shows that a stronger drift relaxation takes place in the multifluid plasma approach. Also, in both approaches the same drift relaxation level is reached within the same time Δt≈700 ωpe−1. This is due to the common mechanism of anomalous transport—charge separation—in multifluid and kinetic approach during the initial stage of the electron beam relaxation. By carrying out a wave-particle interaction analysis in velocity space, it is shown that, however, the essentially kinetic effects Landau damping and particle trapping stop further current relaxation when the bulk drifts velocity has reached the thermal velocity value. In conclusion, it is argued that in this situation, an additional anomalous transport term is required for a complete multifluid plasma description of the electron beam relaxation.
Communications: The electronic spectrum of Li(NH3)4
Authors: Varriale Luigi , Tonge Nicola M. , Bhalla Nitika , Ellis Andrew M.
Published: April 2010

Li ( NH 3 ) 4 has been proposed as a key entity in lithium-ammonia solutions, but its spectral signature has so far proved impossible to distinguish from other species in these solutions. Here we report the first electronic spectrum of Li(NH3)4 in the gas phase, which was recorded using mass-selective depletion spectroscopy. Strong absorption is observed in the near-infrared and the band system is assigned to the Ã T22-X̃ A21 transition in a nominally tetrahedral complex. However, the vibrational structure is indicative of a substantial Jahn–Teller effect in the excited electronic state. The broad and structured spectrum confirms a recent theoretical prediction that the electronic spectrum of Li(NH3)4 will strongly overlap with the spectrum of the solvated electron in lithium-ammonia solutions.
Kirkwood–Buff integrals for ideal solutions
Authors: Ploetz Elizabeth A. , Bentenitis Nikolaos , Smith Paul E.
Published: April 2010

The Kirkwood–Buff (KB) theory of solutions is a rigorous theory of solution mixtures which relates the molecular distributions between the solution components to the thermodynamic properties of the mixture. Ideal solutions represent a useful reference for understanding the properties of real solutions. Here, we derive expressions for the KB integrals, the central components of KB theory, in ideal solutions of any number of components corresponding to the three main concentration scales. The results are illustrated by use of molecular dynamics simulations for two binary solutions mixtures, benzene with toluene, and methanethiol with dimethylsulfide, which closely approach ideal behavior, and a binary mixture of benzene and methanol which is nonideal. Simulations of a quaternary mixture containing benzene, toluene, methanethiol, and dimethylsulfide suggest this system displays ideal behavior and that ideal behavior is not limited to mixtures containing a small number of components.
From single- to double-first-order magnetic phase transition in magnetocaloric Mn1−xCrxCoGe compounds
Authors: Trung N. T. , Biharie V. , Zhang L. , Caron L. , Buschow K. H. J. , Brück E.
Published: April 2010

Substitution of some Cr for Mn atoms in MnCoGe was employed to control the magnetic and structural transitions in this alloy to coincide, leading to a single first-order magnetostructural transition from the ferromagnetic to the paramagnetic state with a giant magnetocaloric effect observed near room temperature. Further increase in the Cr content in the Mn1−xCrxCoGe alloys can induce another first-order magnetoelastic transition from the antiferromagnetic to the ferromagnetic state occurring at lower temperature. The giant magnetocaloric effect as well as the simultaneous tunability of the two magnetic transitions make these materials promising for future cooling applications.
Effect of thermal annealing on properties of InSbN grown by molecular beam epitaxy
Authors: Lim K. P. , Pham H. T. , Yoon S. F. , Ngo C. Y. , Tripathy S.
Published: April 2010

We study the annealing effects on the properties of as-grown InSbN films. The annihilation of donor defects in the form of N-N interstitials is suggested by the shifting of N induced tensile strain and a decrease in free electron concentration from ∼1×1018 to device level of ∼2×1016 cm−3. These findings support the argument that N interstitials thermally dissociate into single N. Corresponding signatures for the reduced Sb antisites and N-N interstitial defects are apparent in Raman spectra. This work will benefit those working on long wavelength infrared photodetectors.
The configurational entropy of mixing of interstitials solid solutions
Authors: Garcés Jorge
Published: April 2010

A simple and general expression for the configurational entropy of mixing of multicomponent interstitials solid solutions is deduced based on a probabilistic approach to compute the configurational entropy. The good agreement obtained with previous experimental and theoretical works based on Monte Carlo and partial configurational entropy calculations in binary systems show that the expression is suitable to be used as a reference state to compute the excess thermodynamic functions in multicomponent interstitials solid solutions. The results show that the configurational entropy can be computed to a high degree of accuracy in some systems without the use of a computer.
Optical properties and electrical bistability of CdS nanoparticles synthesized in dodecanethiol
Authors: Tang Aiwei , Teng Feng , Hou Yanbing , Wang Yongsheng , Tan Furui , Qu Shengchun , Wang Zhanguo
Published: April 2010

We reported the synthesis of CdS semiconductor nanoparticles using a simple one-pot reaction by thermolysis of cadmium acetylacetonate in dodecanethiol. Optical measurements of the as-obtained CdS nanoparticles revealed that their optical properties were closely related to surface effects. Based upon the cocktail of poly(N-vinylcarbazole) (PVK) and CdS nanoparticles, a bistable device was fabricated by a simple solution processing technique. Such a device exhibited a remarkable electrical bistability, which was attributed to the electric field-assisted charge transfer between PVK and the CdS nanoparticles capped by dodecaethiol. The conduction mechanism changed from an injection-controlled current to a bulk-controlled one during switching from OFF-state to ON-state.
Solvation-induced one-dimensional polarons and electron transfer
Authors: Ussery G. L. , Gartstein Yu. N.
Published: April 2010

When a one-dimensional (1D) semiconductor nanostructure is immersed in a sluggish polar solvent, fluctuations of the medium may result in the appearance of localized electronic levels inside the band gap. An excess charge carrier can occupy such a level and undergo self-localization into a large-radius adiabatic polaron surrounded by a self-consistent medium polarization pattern. Within an appropriately adapted framework of the Marcus theory, we explore the description and qualitative picture of thermally activated electron transfer involving solvation-induced polaroniclike states by considering transfer between small and 1D species as well as between two 1D species. Illustrative calculations are performed for tubular geometries with possible applications to carbon nanotube systems.
Experimental verification of a tunable left-handed material by bias magnetic fields
Authors: Poo Yin , Wu Rui-xin , He Guang-hua , Chen Ping , Xu Jie , Chen Ri-feng
Published: April 2010

We designed a two-dimensional periodic composite made of ferrite rods and metallic wires, and theoretically proved the composite in magnetized state had a tunable left-handed material (LHM) regime by its transmission properties and the retrieved effective permittivity and permeability. Further, we fabricated a sample as designed, and experimentally demonstrated the LHM regime by the sample’s abnormal transmission in bias magnetic fields. The abnormal transmission changes with the intensity of the bias magnetic field showing the frequency tunable character of the LHM regime.
Enhanced generation of single optically active spins in diamond by ion implantation
Authors: Naydenov Boris , Richter V. , Beck Johannes , Steiner Matthias , Neumann Philipp , Balasubramanian Gopalakrishnan , Achard Jocelyn , Jelezko Fedor , Wrachtrup Jörg , Kalish Rafi
Published: April 2010

The nitrogen-vacancy (NV) centers in diamond are amongst the most promising candidates for quantum information applications. Up to now the creation of such defects was highly probabilistic, requiring many copies of the nanodevice. Here we show that by employing a two step implantation process which includes low dose N2+ molecular ion implantations followed by high dose C implantation can increase the generation efficiency of NV centers by over 50%. Moreover, we detected intrinsic N14 concentration as low as 0.07 ppb by converting the nitrogen impurities into NV and then counting the single centers by using a confocal microscope.
Position dependent photodetector from large area reduced graphene oxide thin films
Authors: Ghosh Surajit , Sarker Biddut K. , Chunder Anindarupa , Zhai Lei , Khondaker Saiful I.
Published: April 2010

We fabricated large area infrared photodetector devices from thin film of chemically reduced graphene oxide (RGO) sheets and studied their photoresponse as a function of laser position. We found that the photocurrent either increases, decreases, or remain almost zero depending upon the position of the laser spot with respect to the electrodes. The position sensitive photoresponse is explained by Schottky barrier modulation at the RGO film-electrode interface. The time response of the photocurrent is dramatically slower than single sheet of graphene possibly due to disorder from the chemical synthesis and interconnecting sheets.
Moving Glass Patterns: Asymmetric Interaction between Motion and form
Authors: Or Charles C-F , Khuu Sieu K , Hayes Anthony
Published: April 2010

The perceived motion direction of a moving Glass pattern is influenced by the orientation of the dot pairs (dipoles) that generate the pattern (Krekelberg et al, 2003 Nature424 674–677; Ross, 2004 Vision Research44 441–448). Here, we investigate how the motion vector and the dipole orientation of moving Glass patterns influence the perceived orientation of each. We employed 1 s movie presentations of sequences of linear Glass patterns, each consisting of 200 dot pairs. Signal pairs, aligned in a common orientation, moved in a common direction. The observer's task was to indicate either the perceived direction of motion, or the perceived dipole orientation of Glass patterns that consisted of either same-polarity dipoles, or opposite-polarity dipoles. Perceived orientation or motion direction was measured as a function of the angular difference between the orientation and the motion direction of the dipoles. We found that the apparent global direction of motion was attracted by approximately 4° towards the dipole orientation for small (15°, 23°) angular differences between dipole motion-direction and dipole orientation, regardless of dipole polarity. However, under the same stimulus conditions, the apparent global orientation was much less affected by the direction of motion, suggesting that motion and form interact asymmetrically. Global form influences global motion-direction perception more powerfully than global motion influences global form perception.
Direct Evidence for the Economy of Action: Glucose and the Perception of Geographical Slant
Authors: Schnall Simone , Zadra Jonathan R , Proffitt Dennis R
Published: April 2010

When locomoting in a physically challenging environment, the body draws upon available energy reserves to accommodate increased metabolic demand. Ingested glucose supplements the body's energy resources, whereas non-caloric sweetener does not. Two experiments demonstrate that participants who had consumed a glucose-containing drink perceived the slant of a hill to be less steep than did participants who had consumed a drink containing non-caloric sweetener. The glucose manipulation influenced participants' explicit awareness of hill slant but, as predicted, it did not affect a visually guided action of orienting a tilting palmboard to be parallel to the hill. Measured individual differences in factors related to bioenergetic state, such as fatigue, sleep quality, fitness, mood, and stress, also affected perception: lower energetic states were associated with steeper perceptions of hill slant. This research shows that the perception of the spatial layout of the environment is influenced by the energetic resources available for locomotion within it. Our findings are consistent with the view that spatial perceptions are influenced by bioenergetic factors.
The ‘Bookshelf Illusion’—A Real-World Zöllner-Type Illusion?
Authors: MacLin Otto H , Peterson Dwight J
Published: April 2010

We discovered an interesting perceptual distortion in our office where an upright lamp in front of a bookshelf was noticeably curved to form several subtle S-shaped bends. We realized that the books in the bookshelf fell in a particular manner, leaning in alternative directions, which caused the straight lamp to appear bent, creating what may be a real-world example of the Zöllner illusion. Evidence for the production of the illusion diagrammatically and an explanation for the effect are provided.
Validation of a portable flow injection - chemiluminescence (FI-CL) method for the determination of dissolved iron in Atlantic open ocean and shelf waters by comparison with isotope dilution - inductively coupled plasma mass spectrometry (ID-ICPMS)
Authors: Ussher Simon J. , Petrov Ivan , Quétel Christophe R. , Worsfold Paul J.
Published: April 2010

Environmental context. The importance of iron as a limiting micronutrient for primary production in the marine environment and its complex marine biogeochemical cycle necessitate accurate methods for the determination of iron in seawater. Current analytical challenges include the detection of trace concentrations (sub-nanomolar) and the high potential for contamination and matrix interferences. To improve confidence in dissolved iron data, intercomparison exercises of commonly used analytical methods are required that demonstrate their applicability to different water masses.
Abstract. A blind intercomparison exercise was carried out to validate a well documented, portable flow injection–chemiluminescence (FI-CL) method for the determination of iron in seawater. This was done by the analysis of a variety of filtered Atlantic Ocean samples using FI-CL and a potential primary method of measurement, isotope dilution–inductively coupled plasma mass spectrometry (ID-ICPMS). To investigate the effect of the seawater matrix at various concentrations of iron, samples were collected at various depths (0–200 m) from different water masses (European Continental Shelf, the South Atlantic Ocean) and filtered through both 0.02- and 0.2-μm pore size filters. The exercise was conducted under controlled conditions using the same bottles transported between laboratories to avoid between-bottle inhomogeneity. The results generally showed good agreement between the two methods for dissolved iron over the concentration range 0.15 to 2.1 nM. However, some samples were not in agreement according to estimated uncertainties and this was attributed to random errors arising from contamination during sample handling and matrix effects (i.e. variable interferences) rather than systematic errors.
Assessment of the pollution potential of mercury contaminated biosolids
Authors: Lomonte Cristina , Fritsche Johannes , Bramanti Emilia , Doronila Augustine , Gregory David , Baker Alan J. M. , Kolev Spas D.
Published: April 2010

Environmental context. The re-use of biosolids (sewage sludge) is becoming increasingly popular especially for land applications as soil improvers, fertilisers and composts. However, some biosolids are contaminated with toxic heavy metals and mercury is arguably of the highest environmental and public health concern. Studies on mobility, availability and emissions of mercury from biosolids were carried out to assess the biosolids potential for contamination of the environment and to evaluate applicable techniques for a future remediation. Abstract. Biosolids from Melbourne Water’s Western Treatment Plant (WTP) in Australia contain elevated levels of mercury. Consequently, monitoring programs are crucial in order to assess localised impacts to the environment and on humans immediately surrounding the boundaries of the WTP. Dry biosolids were surveyed for Hg, other heavy metals, cations, soluble anions, sulfur and phosphorus. Mercury concentrations were found to vary between 3.5 and 8.4 mg kg–1 Hg, indicating that biosolids from some locations were above the safety level (5 mg kg–1 Hg) for land applications. High concentrations of soluble anions and cations revealed elevated salinity levels. The biosolids with the highest Hg concentration were further studied to assess their potential for Hg remediation. The results obtained by a sequential extraction procedure showed that 59.01% of the total mercury was complexed with organic ligands. In addition, the influence of air temperature, water content and irradiation on the emission of gaseous elemental mercury from biosolids was studied. Light exposure and water addition were the main factors affecting this emission with flux values up to 132 ng m–2 h–1.
A comparative evaluation of water uptake on several mineral dust sources
Authors: Navea Juan G. , Chen Haihan , Huang Min , Carmichel Gregory R. , Grassian Vicki H.
Published: April 2010

Environmental context. Dust particles produced from wind blown soils are of global significance as these dust particles not only impact visibility, as evident in the recent 2009 Australian dust storm, but also atmospheric chemistry, climate and biogeochemical cycles. The amount of water vapour in the atmosphere (relative humidity) can play a role in these global processes yet there are few studies and little quantitative data on water-dust particle interactions. The focus of this research is on quantifying water-dust particle interactions for several dust sources including Asia and Africa where dust storms are most prevalent.
Abstract. Mineral dust aerosol provides a reactive surface in the troposphere. The reactivity of mineral dust depends on the source region as chemical composition and mineralogy of the aerosol affects its interaction with atmospheric gases. Furthermore, the impact of mineral dust aerosol in atmospheric processes and climate is a function of relative humidity. In this study, we have investigated water uptake of complex dust samples. In particular, water uptake as a function of relative humidity has been measured on three different dust sources that have been characterised using a variety of bulk and surface techniques. For these well-characterised dust samples, it is shown that although there are variations in chemical composition and mineralogy, on a per mass basis, water uptake capacities for the three dusts are very similar and are comparable to single component clay samples. These results suggest that the measured uptake of water of these bulk samples is dominated by the clay component.
Arsenic speciation in marine organisms from Antarctic coastal environments
Authors: Grotti Marco , Lagomarsino Cristina , Goessler Walter , Francesconi Kevin A.
Published: April 2010

Environmental context. In studies on trace element accumulation and transformation, it is difficult to distinguish the relative contribution of natural and anthropogenic sources. Antarctic ecosystems provide the opportunity to investigate the natural cycles of the elements, because the food webs are relatively simple and trace element contamination from anthropogenic sources is negligible. We report the arsenic species in various tissues from a range of Antarctic organisms, and compare the patterns of arsenicals with those from similar studies in temperate and tropical waters. Abstract. Antarctic coastal environments offer the unique opportunity to study elemental cycling under pristine conditions. We report arsenic species in various tissues from a range of Antarctic organisms collected from coastal environments, and compare our results with those from similar studies in temperate and tropical waters. The arsenic species were determined in aqueous methanol extracts of tissues (including muscle, liver, gonads and spleen) by HPLC/ICPMS. The major compounds were arsenobetaine and oxo-arsenosugars, with their relative proportions depending on the position of the organism in the food chain and, for some species, on the type of tissue analysed. Several minor compounds, such as dimethylarsinate, trimethylarsine oxide, trimethylarsoniopropionate and arsenocholine were also found; the concentrations of these arsenic species were significantly lower in muscle compared with the other tissues. The transfer of the arsenic through the Antarctic marine food web and the speciation patterns found in the organisms were similar to those reported for comparable organisms from other marine ecosystems. Our study supports the view that the high levels of arsenic occurring in various forms in marine samples is a natural phenomenon, and is little influenced by anthropogenic activities.
Trans-synaptic EphB2–ephrin–B3 interaction regulates excitatory synapse density by inhibition of postsynaptic MAPK signaling
Authors: McClelland Andrew C. , Hruska Martin , Coenen Andrew J. , Henkemeyer Mark , Dalva Matthew B.
Published: April 2010

Nervous system function requires tight control over the number of synapses individual neurons receive, but the underlying cellular and molecular mechanisms that regulate synapse number remain obscure. Here we present evidence that a trans-synaptic interaction between EphB2 in the presynaptic compartment and ephrin-B3 in the postsynaptic compartment regulates synapse density and the formation of dendritic spines. Observations in cultured cortical neurons demonstrate that synapse density scales with ephrin-B3 expression level and is controlled by ephrin-B3–dependent competitive cell–cell interactions. RNA interference and biochemical experiments support the model that ephrin-B3 regulates synapse density by directly binding to Erk1/2 to inhibit postsynaptic Ras/mitogen-activated protein kinase signaling. Together these findings define a mechanism that contributes to synapse maturation and controls the number of excitatory synaptic inputs received by individual neurons.
A brain-specific cytochrome P450 responsible for the majority of deltamethrin resistance in the QTC279 strain of
Tribolium castaneum
Authors: Zhu Fang , Parthasarathy R. , Bai Hua , Woithe Katharina , Kaussmann Martin , Nauen Ralf , Harrison Douglas A. , Palli Subba R.
Published: April 2010

Cytochrome P450-mediated detoxification is one of the most important mechanisms involved in insecticide resistance. However, the molecular basis of this mechanism and the physiological functions of P450s associated with insecticide resistance remain largely unknown. Here, we exploited the functional genomics and reverse genetic approaches to identify and characterize a P450 gene responsible for the majority of deltamethrin resistance observed in the QTC279 strain of
Tribolium castaneum
. We used recently completed whole-genome sequence of
T. castaneum
to prepare custom microarrays and identified a P450 gene,
CYP6BQ9
, which showed more than a 200-fold higher expression in the deltamethrin-resistant QTC279 strain when compared with its expression in the deltamethrin-susceptible Lab-S strain. Functional studies using both double-strand RNA (dsRNA)-mediated knockdown in the expression of
CYP6BQ9
and transgenic expression of
CYP6BQ9
in
Drosophila melanogaster
showed that
CYP6BQ9
confers deltamethrin resistance. Furthermore, CYP6BQ9 enzyme expressed in baculovirus metabolizes deltamethrin to 4-hydroxy deltamethrin. Strikingly, we also found that unlike many P450 genes involved in insecticide resistance that were reported previously,
CYP6BQ9
is predominantly expressed in the brain, a part of the central nervous system (CNS) containing voltage-gated sodium channels targeted by deltamethrin. Taken together, the current studies on the brain-specific insect P450 involved in deltamethrin resistance shed new light on the understanding of the molecular basis and evolution of insecticide resistance.
Pseudo-Outbreak ofClostridium sordelliiInfection following Probable Cross-Contamination in a Hospital Clinical Microbiology Laboratory
Authors: Aronoff David M. , Thelen Tennille , Walk Seth T. , Petersen Kathleen , Jackson Julia , Grossman Sylvia , Rudrik James , Newton Duane W. , Chenoweth Carol E.
Published: April 2010

We report a pseudo-outbreak of infection caused byClostridium sordellii, an uncommon human pathogen. The pseudo-outbreak involved 6 patients and was temporally associated with a change by the clinical microbiology laboratory in the protocol of handling anaerobic culture specimens. All isolates were genetically indistinguishable from a laboratory reference strain used for quality control.
Special issue containing papers presented at the 4th IAEA Technical Meeting on the Theory of
Plasma Instabilities
Authors: K. Itoh  , H. R. Wilson
Published: April 2010

The 4th IAEA technical meeting (TM) on the Theory of Plasma Instabilities
was held in Kyoto, May 18th--20th 2009, following the first (Seeon), second
(Trieste) and third (York) meetings in this series. This IAEA-TM was motivated
by the recent advances in theoretical methodology, the rapid progress in
observations of laboratory and astrophysical plasmas and the evolution of
fusion research as we approach the ITER era. The international advisory
committee (IAC) and local organizing committee (LOC), the members of which are
listed below, collaborated to define the scope and the content of the scientific
programme.

Young scientists were actively encouraged to participate in this TM
to help stimulate their future research careers and raise their international
profiles. Through these young scientists, the IAEA-TM planned to identify the
future directions of research. About 90 researchers, from 13 countries and the IAEA,
participated in this IAEA-TM, with 72 scientific presentations. The talks and
posters generated enthusiastic discussions, contributing to the vibrancy of the
meeting.

This special issue of Nuclear Fusion consists of a cluster of papers, reporting
some of the main contributions to the IAEA-TM. The articles in this cluster are
representative of the scientific width of presentations at the meeting, spanning
topics from micro-turbulence to large-scale MHD dynamics and from transport to
detailed analysis of diagnostics. They demonstrate the quality and depth of the
research presented at the conference.

List of IAC (alphabetical order):

B. Breizman (USA), S. Guenter (Germany), T. S. Hahm (USA), K. Itoh (Japan, Chair of 2009), Ya. I. Kolesnichenko (Ukraine), A. G. Peeters (UK), H. Wilson (UK)

List of LOC (alphabetical order):

A. Fukuyama, R. Horiuchi, S.-I. Itoh, N. Kasuya, Y. Kishimoto (co-chair), K. Kusano, J. Li, K. Mima, S. Murakami, H. Naitou, N. Nakajima, Y. Nakamura, H. Ohtani, S. Okamura, T. Ozeki, S. Sudo (co-chair), H. Sugama, Y. Todo, S. Tokuda, S. Usami, M. Yagi, Z. Yoshida
Summary of IAEA Technical Meeting on Theory of Plasma Instabilities
Authors: Itoh Kimitaka
Published: April 2010

This review summarizes the key progresses, which were reported in the IAEA Technical Meeting on Theory of Plasma Instabilities (Kyoto 2009). An assessment is formulated by focusing on the evolution from ‘linear, local, deterministic’ theories to ‘nonlinear, nonlocal, statistical’ theories.
Electromagnetic effects on geodesic acoustic and beta-induced Alfvén eigenmodes
Authors: Smolyakov A.I. , Nguyen C. , Garbet X.
Published: April 2010

The local kinetic theory of geodesic acoustic modes and beta-induced Alfvén eigenmodes is developed. The local dispersion relations are derived in two opposite limits:
and
, where k
0 = (m − nq)/qR, m and n are poloidal and toroidal mode numbers, and
is the electron thermal velocity. It is shown that the nature of the (m ± 1, n) sideband oscillations depends on the radial modes width. The localized modes are mostly electrostatic, while the meso-scale modes of the radial width larger than c/(ωpi
q) have a strong electromagnetic component. It is shown that the dispersion relations are remarkably similar provided the radial mode width of the principal (m, n) harmonic is sufficiently small.
Selective formation of streamers in magnetized cylindrical plasmas
Authors: Kasuya Naohiro , Yagi Masatoshi , Itoh Kimitaka , Itoh Sanae-I.
Published: April 2010

Turbulent plasmas form a variety of mesoscale structures, which affect the level of anomalous transport in fusion plasmas. A streamer is a poloidally localized, radially elongated vortex, which increases convective transport. We have carried out numerical simulations of resistive drift wave turbulence in a linear configuration, as a minimal model for analysing the structural formation mechanism in magnetized plasmas by mode coupling. A three-field reduced MHD model is extended to describe the resistive drift wave turbulence in cylindrical plasmas. A poloidally localized turbulent structure, which has the typical temporal scale of the streamer, is formed by the self-bunching of a couple of unstable modes in nonlinear saturation states. The formed structure depends on the magnitude of the ion–neutral collision frequency, which is the damping parameter of the zonal flow, and the streamer is formed when the damping of the zonal flow is stronger than that of the intermediate mode for the streamer formation. We found that the streamer is selectively formed to keep the particle balance as long as the drift wave is unstable.
Neuralized Promotes Basal to Apical Transcytosis of Delta in Epithelial Cells
Authors: Benhra Najate , Vignaux Françoise , Dussert Aurore , Schweisguth François , Le Borgne Roland
Published: April 2010

Notch receptors mediate short-range signaling controlling many developmental decisions in metazoans. Activation of Notch requires the ubiquitin-dependent endocytosis of its ligand Delta. How ligand endocytosis in signal-sending cells regulates receptor activation in juxtaposed signal-receiving cells remains largely unknown. We show here that a pool of Delta localizes at the basolateral membrane of signal-sending sensory organ precursor cells in the dorsal thorax neuroepithelium of Drosophila and that Delta is endocytosed in a Neuralized-dependent manner from this basolateral membrane. This basolateral pool of Delta is segregated from Notch that accumulates apically. Using a compartimentalized antibody uptake assay, we show that murine Delta-like 1 is similarly internalized by mNeuralized2 from the basolateral membrane of polarized Madin-Darby canine kidney cells and that internalized ligands are transcytosed to the apical plasma membrane where mNotch1 accumulates. Thus, endocytosis of Delta by Neuralized relocalizes Delta from the basolateral to the apical membrane domain. We speculate that this Neuralized-dependent transcytosis regulates the signaling activity of Delta by relocalizing Delta from a membrane domain where it cannot interact with Notch to another membrane domain where it can bind and activate Notch.
O-GlcNAc Cycling Enzymes Associate with the Translational Machinery and Modify Core Ribosomal Proteins
Authors: Zeidan Quira , Wang Zihao , De Maio Antonio , Hart Gerald W.
Published: April 2010

Protein synthesis is globally regulated through posttranslational modifications of initiation and elongation factors. Recent high-throughput studies have identified translation factors and ribosomal proteins (RPs) as substrates for the O-GlcNAc modification. Here we determine the extent and abundance of O-GlcNAcylated proteins in translational preparations. O-GlcNAc is present on many proteins that form active polysomes. We identify twenty O-GlcNAcylated core RPs, of which eight are newly reported. We map sites of O-GlcNAc modification on four RPs (L6, L29, L32, and L36). RPS6, a component of the mammalian target of rapamycin (mTOR) signaling pathway, follows different dynamics of O-GlcNAcylation than nutrient-induced phosphorylation. We also show that both O-GlcNAc cycling enzymes OGT and OGAse strongly associate with cytosolic ribosomes. Immunofluorescence experiments demonstrate that OGAse is present uniformly throughout the nucleus, whereas OGT is excluded from the nucleolus. Moreover, nucleolar stress only alters OGAse nuclear staining, but not OGT staining. Lastly, adenovirus-mediated overexpression of OGT, but not of OGAse or GFP control, causes an accumulation of 60S subunits and 80S monosomes. Our results not only establish that O-GlcNAcylation extensively modifies RPs, but also suggest that O-GlcNAc play important roles in regulating translation and ribosome biogenesis.