bluuebunny/crossref_metadata_2025 huggingface dataset:
Using Finiteness as a Clinical Marker to Identify Language Impairment
Authors: Ash Andrea C. , Redmond Sean M.
Published: December 2014

Intervention rates for children with language impairments vary widely across reports. Unfortunately, many language tests focus on areas of language that are not problematic for children with language impairments (LI). Over twenty years of research supports limitations in finiteness as a clinical marker of LI. However, speech language pathologists (SLPs) have been reluctant to include assessments of finiteness in clinical decisions for young school-age children. This article addresses the operational definition of finiteness which may have created a barrier to its clinical use. We recommend that SLPs include the Test of Early Grammatical Impairment as a primary measure of finiteness for identifying language impairment in children between 3 and 8 years of age because of its clinical flexibility and high levels of sensitivity and specificity.
Cervical Synovial Cyst Causing Cervical Radiculomyelopathy: Case Report and Review of the Literature
Authors: Corredor José A. , Quan Gerald
Published: December 2014

Study Design

Case report.

Objective

Synovial cysts in the subaxial cervical spine are rare and are most commonly reported at the cervicothoracic junction. Only six cases of symptomatic C5–C6 synovial cysts have been reported in the literature; the condition is usually treated with decompressive laminectomy. We present a patient with a synovial cyst arising from the C5–C6 facet joint, associated with spondylolisthesis, and causing radiculomyelopathy. The patient was treated with a posterior excision of the cyst, decompressive laminectomy, and fusion.

Methods

A 67-year-old man had vertebral canal stenosis at C5–C6 secondary to a synovial cyst and spondylolisthesis with symptoms and signs of radiculopathy and myelopathy. Surgical management involved C5–C6 posterior decompressive laminectomy and excision of the cyst and C4–C6 instrumented fusion with lateral mass screws and rods. A literature review of symptomatic cervical synovial cysts is presented.

Results

The imaging studies identified grade I spondylolisthesis and a 3.3 × 4.3-mm extradural lentiform-like mass associated with focal compression of the spinal cord and exiting the C6 nerve root. After the surgery, the patient had an immediate full recovery and was asymptomatic by the 6-month examination. No operative complications were reported. The histologic report confirmed the presence of a synovial cyst.

Conclusions

C5–C6 is an unusual localization for symptomatic synovial cysts. Similar cases reported in the literature achieved excellent results after cyst excision and decompressive laminectomy. Because spondylolisthesis plus laminectomy are risk factors for segmental instability in the cervical spine, we report a case of a C5–C6 facet synovial cyst successfully treated with posterior laminectomy and C4–C6 fusion.
High pressure study of a highly energetic nitrogen-rich carbon nitride, cyanuric triazide
Authors: Laniel Dominique , Downie Laura E. , Smith Jesse S. , Savard Didier , Murugesu Muralee , Desgreniers Serge
Published: December 2014

Cyanuric triazide (CTA), a nitrogen-rich energetic material, was compressed in a diamond anvil cell up to 63.2 GPa. Samples were characterized by x-ray diffraction, Raman, and infrared spectroscopy. A phase transition occurring between 29.8 and 30.7 GPa was found by all three techniques. The bulk modulus and its pressure derivative of the low pressure phase were determined by fitting the 300 K isothermal compression data to the Birch-Murnaghan equation of state. Due to the strong photosensitivity of CTA, synchrotron generated x-rays and visible laser radiation both lead to the progressive conversion of CTA into a two dimensional amorphous C=N network, starting from 9.2 GPa. As a result of the conversion, increasingly weak and broad x-ray diffraction lines were recorded from crystalline CTA as a function of pressure. Hence, a definite structure could not be obtained for the high pressure phase of CTA. Results from infrared spectroscopy carried out to 40.5 GPa suggest the high pressure formation of a lattice built of tri-tetrazole molecular units. The decompression study showed stability of the high pressure phase down to 13.9 GPa. Finally, two CTA samples, one loaded with neon and the other with nitrogen, used as pressure transmitting media, were laser-heated to approximately 1100 K and 1500 K while compressed at 37.7 GPa and 42.0 GPa, respectively. In both cases CTA decomposed resulting in amorphous compounds, as recovered at ambient conditions.
Nanorheology by atomic force microscopy
Authors: Li Tai-De , Chiu Hsiang-Chih , Ortiz-Young Deborah , Riedo Elisa
Published: December 2014

We present an Atomic Force Microscopy (AFM) based method to investigate the rheological properties of liquids confined within a nanosize gap formed by an AFM tip apex and a solid substrate. In this method, a conventional AFM cantilever is sheared parallel to a substrate surface by means of a lock-in amplifier while it is approaching and retracting from the substrate in liquid. The normal solvation forces and lateral viscoelastic shear forces experienced by the AFM tip in liquid can be simultaneously measured as a function of the tip-substrate distance with sub-nanometer vertical resolution. A new calibration method is applied to compensate for the linear drift of the piezo transducer and substrate system, leading to a more precise determination of the tip-substrate distance. By monitoring the phase lag between the driving signal and the cantilever response in liquid, the frequency dependent viscoelastic properties of the confined liquid can also be derived. Finally, we discuss the results obtained with this technique from different liquid-solid interfaces. Namely, octamethylcyclotetrasiloxane and water on mica and highly oriented pyrolytic graphite.
Ostwald ripening in multiple-bubble nuclei
Authors: Watanabe Hiroshi , Suzuki Masaru , Inaoka Hajime , Ito Nobuyasu
Published: December 2014

The Ostwald ripening of bubbles is studied by molecular dynamics simulations involving up to 679 × 106 Lennard-Jones particles. Many bubbles appear after depressurizing a system that is initially maintained in the pure-liquid phase, and the coarsening of bubbles follows. The self-similarity of the bubble-size distribution function predicted by Lifshitz-Slyozov-Wagner theory is directly confirmed. The total number of bubbles decreases asymptotically as t−x with scaling exponent x. As the initial temperature increases, the exponent changes from x = 3/2 to 1, which implies that the growth of bubbles changes from interface-limited (the t1/2 law) to diffusion-limited (the t1/3 law) growth.
Non-stochastic matrix Schrödinger equation for open systems
Authors: Joubert-Doriol Loïc , Ryabinkin Ilya G. , Izmaylov Artur F.
Published: December 2014

We propose an extension of the Schrödinger equation for a quantum system interacting with environment. This extension describes dynamics of a collection of auxiliary wavefunctions organized as a matrix m, from which the system density matrix can be reconstructed as \documentclass[12pt]{minimal}\begin{document}$\hat{\rho }= {\bm m} {\bm m}^\dagger$\end{document}ρ̂=mm†. We formulate a compatibility condition, which ensures that the reconstructed density satisfies a given quantum master equation for the system density. The resulting non-stochastic evolution equation preserves positive-definiteness of the system density and is applicable to both Markovian and non-Markovian system-bath treatments. Our formalism also resolves a long-standing problem of energy loss in the time-dependent variational principle applied to mixed states of closed systems.
Microcontroller-based locking in optics experiments
Authors: Huang K. , Le Jeannic H. , Ruaudel J. , Morin O. , Laurat J.
Published: December 2014

Optics experiments critically require the stable and accurate locking of relative phases between light beams or the stabilization of Fabry-Perot cavity lengths. Here, we present a simple and inexpensive technique based on a stand-alone microcontroller unit to perform such tasks. Easily programmed in C language, this reconfigurable digital locking system also enables automatic relocking and sequential functioning. Different algorithms are detailed and applied to fringe locking and to low- and high-finesse optical cavity stabilization, without the need of external modulations or error signals. This technique can readily replace a number of analog locking systems advantageously in a variety of optical experiments.
Testing accelerometer rectification error caused by multidimensional composite inputs with double turntable centrifuge
Authors: Guan W. , Meng X. F. , Dong X. M.
Published: December 2014

Rectification error is a critical characteristic of inertial accelerometers. Accelerometers working in operational situations are stimulated by composite inputs, including constant acceleration and vibration, from multiple directions. However, traditional methods for evaluating rectification error only use one-dimensional vibration. In this paper, a double turntable centrifuge (DTC) was utilized to produce the constant acceleration and vibration simultaneously and we tested the rectification error due to the composite accelerations. At first, we deduced the expression of the rectification error with the output of the DTC and a static model of the single-axis pendulous accelerometer under test. Theoretical investigation and analysis were carried out in accordance with the rectification error model. Then a detailed experimental procedure and testing results were described. We measured the rectification error with various constant accelerations at different frequencies and amplitudes of the vibration. The experimental results showed the distinguished characteristics of the rectification error caused by the composite accelerations. The linear relation between the constant acceleration and the rectification error was proved. The experimental procedure and results presented in this context can be referenced for the investigation of the characteristics of accelerometer with multiple inputs.
Electro-capillary instabilities of thin leaky elastic-viscous bilayers
Authors: Mondal Kartick , Bandyopadhyay Dipankar
Published: December 2014

Electrohydrodynamic stresses originating from the accumulation of free and induced charges at the confined interface of a thin elastic-viscous bilayer composed of weakly conducting elastic or viscous films can stimulate permanent micropatterns such as creases, wrinkles, holes, and columns. We show that a complete linear stability analysis including all the leading order terms from the Maxwell stresses can accurately predict the key short to long-wave transitions in the length scales, as reported recently by the experimental studies. The generic potential employed for the electric field in the present work overcomes the limitations of the existing theories, which could not precisely predict the length scales especially in the short-wave limit. Importantly, unlike the experimentally reported configuration with a dielectric elastic layer confined by a weakly conducting liquid layer, the bilayers with a weakly conducting elastic layer confined by a dielectric liquid layer can develop interfacial patterns with similar periodicity at smaller field intensity. The transitions from long- to short-wave are compared and contrasted for the bilayers with leaky elastic or viscous films by tuning the field intensity, interfacial tension, and thicknesses of the films. The study unveils that the charged interface of a leaky confined bilayer experiences a larger stress due to the accumulation of free and bound charges, which can significantly reduce the length scales of the instability to the sub-micron regime. The results reported can stimulate further investigation related to the patterning and miniaturization exploiting the field induced instabilities of the elastic films.
Ion kinetic effects on the ignition and burn of inertial confinement fusion targets: A multi-scale approach
Authors: Peigney B. E. , Larroche O. , Tikhonchuk V.
Published: December 2014

In this article, we study the hydrodynamics and burn of the thermonuclear fuel in inertial confinement fusion pellets at the ion kinetic level. The analysis is based on a two-velocity-scale Vlasov-Fokker-Planck kinetic model that is specially tailored to treat fusion products (suprathermal α-particles) in a self-consistent manner with the thermal bulk. The model assumes spherical symmetry in configuration space and axial symmetry in velocity space around the mean flow velocity. A typical hot-spot ignition design is considered. Compared with fluid simulations where a multi-group diffusion scheme is applied to model α transport, the full ion-kinetic approach reveals significant non-local effects on the transport of energetic α-particles. This has a direct impact on hydrodynamic spatial profiles during combustion: the hot spot reactivity is reduced, while the inner dense fuel layers are pre-heated by the escaping α-suprathermal particles, which are transported farther out of the hot spot. We show how the kinetic transport enhancement of fusion products leads to a significant reduction of the fusion yield.
Wettability of graphene-laminated micropillar structures
Authors: Bong Jihye , Seo Keumyoung , Park Ji-Hoon , Ahn Joung Real , Ju Sanghyun
Published: December 2014

The wetting control of graphene is of great interest for electronic, mechanical, architectural, and bionic applications. In this study, the wettability of graphene-laminated micropillar structures was manipulated by changing the height of graphene-laminated structures and employing the trichlorosilane (HDF-S)-based self-assembly monolayer. Graphene-laminated micropillar structures with HDF-S exhibited higher hydrophobicity (contact angle of 129.5°) than pristine graphene thin film (78.8°), pristine graphene-laminated micropillar structures (97.5°), and HDF-S self-assembled graphene thin film (98.5°). Wetting states of the graphene-laminated micropillar structure with HDF-S was also examined by using a urea solution, which flowed across the surface without leaving any residues.
Automated spherical aberration correction in scanning confocal microscopy
Authors: Yoo H. W. , van Royen M. E. , van Cappellen W. A. , Houtsmuller A. B. , Verhaegen M. , Schitter G.
Published: December 2014

Mismatch between the refractive indexes of immersion media and glass coverslips introduces spherical aberrations in microscopes especially for high numerical aperture objectives. This contribution demonstrates an automated adjustment of the coverslip correction collar in scanning confocal microscopy to compensate for spherical aberrations due to coverslip thickness mismatch. With a motorized coverslip correction collar, the adjustment procedure consists of xz image scans, image processing, correction quality evaluation, the mismatch estimation, and eventually the optimal adjustment of the correction collar. For fast correction with less photodamage, coarse-fine Gaussian fitting algorithms are proposed and evaluated with various specimen for their estimation accuracy. The benefits of the proposed automated correction are demonstrated for various coverslips with biological specimens, showing the optimized resolution of the confocal microscope.
Effects of copper nanoparticle inclusions on pressure-induced fluid-polynanocrystalline structural transitions in krypton
Authors: Chen Zhen , Jiang Shan , Sewell Thomas D. , Gan Yong , Oloriegbe Suleiman Y. , Thompson Donald L.
Published: December 2014

The dependence of nanoscale crystal formation from a noble element fluid on the rate of hydrodynamic compression was explored using molecular dynamics. Results were obtained for pure krypton samples as well as ones containing a cubic- or spherical-shaped fcc copper nanocrystal inclusion for compression rates of 1, 10, and 20 MPa/ps. In the absence of Cu, Kr crystals nucleate with apparently random locations and orientations in the sample; slower compression leads to larger nanocrystal size. The effect of the Cu inclusion is to partially mediate the location, orientation, and size of the formed crystals. The effect is larger for the slower compression rate and when the inclusion is cubic rather than spherical in shape. For sufficiently slow compression, the stress state in the cubic Cu inclusion changes from hydrostatic to non-hydrostatic as a consequence of the formation of extended orthotropic hcp/fcc nanostructures in the Kr. The mechanism of the dynamic stress-induced nanostructural transition is explained qualitatively in terms of known geometric effects on the quasi-static indentation response of crystalline materials.
Measurement of the anisotropic thermal conductivity of molybdenum disulfide by the time-resolved magneto-optic Kerr effect
Authors: Liu Jun , Choi Gyung-Min , Cahill David G.
Published: December 2014

We use pump-probe metrology based on the magneto-optic Kerr effect to measure the anisotropic thermal conductivity of (001)-oriented MoS2 crystals. A ≈20 nm thick CoPt multilayer with perpendicular magnetization serves as the heater and thermometer in the experiment. The low thermal conductivity and small thickness of the CoPt transducer improve the sensitivity of the measurement to lateral heat flow in the MoS2 crystal. The thermal conductivity of MoS2 is highly anisotropic with basal-plane thermal conductivity varying between 85–110 W m-1 K-1 as a function of laser spot size. The basal-plane thermal conductivity is a factor of ≈50 larger than the c-axis thermal conductivity, 2.0±0.3 W m-1 K-1.
Investigation of surface defect states in CeO2-y nanocrystals by Scanning−tunneling microscopy/spectroscopy and ellipsometry
Authors: Radović Marko , Stojadinović Bojan , Tomić Nataša , Golubović Aleksandar , Matović Branko , Veljković Ivana , Dohčević-Mitrović Zorana
Published: December 2014

Synthesis process strongly influences the nanocrystalline CeO2-y defective structure. The presence of surface defects, in the form of oxygen vacancies in different charge states (F centers), can change the electronic properties of ceria nanocrystals. Nanocrystalline CeO2-y samples were synthesized using three different methods (precipitation, self-propagating room temperature, and hydrothermal synthesis). Raman spectroscopy was used to identify the presence of oxygen vacancies which presumably were formed at the nanoparticle surface. The defect concentration depended on the crystallite size of differently prepared CeO2-y samples. Scanning tunneling microscopy/spectroscopy and ellipsometry were employed to investigate the electronic band structure of defective CeO2-y nanocrystals. Scanning tunneling spectroscopy measurements demonstrated that inside the band gap of CeO2-y nanocrystals, besides the filled 4 f states, appeared additional states which were related to occupied and empty F center defect states. From the ellipsometric measurements, using the critical points model, the energy positions of different F centers states and the values of the reduced band gap energies were determined. The analysis of obtained data pointed out that depending on the synthesis method, different types of F centers (F+ and F0) can be formed in the CeO2-y nanocrystals. The formation of different F center defect states inside the ceria gap have a strong impact on the electrical, optical, and magnetic properties of ceria nanocrystals.
Superconductivity tuned through magnetic irreversibility in two-dimensional Co/Nb/Co trilayers under a parallel magnetic field
Authors: Stamopoulos D. , Aristomenopoulou E.
Published: December 2014

In ferromagnetic/superconducting (FM/SC) planar hybrids, a reentrance of the upper-critical field line Hc2(T) is observed close to Tc. The effect is generally ascribed to the so-called domain-wall superconductivity and has been theoretically explored in great detail. Experimental investigations are limited mostly to FM/SC bilayers in which the FM layers host out-of-plane magnetic domains of strong anisotropy and large width (>300 nm), the SC layer is quite thick (>30 nm), and the external magnetic field was applied normal. To expand our knowledge to until now unexplored conditions, we study a series of Co(dCo)/Nb(dNb)/Co(dCo) trilayers under a parallel magnetic field; Co outer layers exhibit out-of-plane magnetic domains of weak anisotropy and small width (<150 nm) and the Nb interlayer is very thin (<20 nm). We demonstrate a strong reentrance of Hc2(T) that can be tuned through the irreversible magnetization processes of the FM outer layers, the two-dimensional character of the SC interlayer, and the matching between the interfering SC and FM length scales. These results refine the nature of the reentrance of Hc2(T) in FM/SC hybrids and can motivate new theoretical and experimental investigations.
Effect of moisture on the traction-separation behavior of cellulose nanocrystal interfaces
Authors: Sinko Robert , Keten Sinan
Published: December 2014

Interfaces and stress transfer between cellulose nanocrystals (CNCs) dictate the mechanical properties of hierarchical cellulose materials such as neat films and nanocomposites. An interesting question that remains is how the behavior of these interfaces changes due to environmental stimuli, most notably moisture. We present analyses on the traction-separation behavior between Iβ CNC elementary fibrils, providing insight into how the presence of a single atomic layer of water at these interfaces can drastically change the mechanical behavior. We find that molecular water at the interface between hydrophilic CNC surfaces has a negligible effect on the tensile separation adhesion energy. However, when water cannot hydrogen bond easily to the surface (i.e., hydrophobic surface), it tends to maintain hydrogen bonds with other water molecules across the interface and form a capillary bridge that serves to increase the energy required to separate the crystals. Under shear loading, water lowers the energy barriers to sliding by reducing the atomic friction and consequently the interlayer shear modulus between crystals. Our simulations indicate that these nanoscale interfaces and physical phenomena such as interfacial adhesion, interlayer shear properties, and stick-slip friction behavior can be drastically altered by the presence of water.
Suppression of thermoelectric Thomson effect in silicon microwires under large electrical bias and implications for phase-change memory devices
Authors: Bakan Gokhan , Gokirmak Ali , Silva Helena
Published: December 2014

We have observed how thermoelectric effects that result in asymmetric melting of silicon wires are suppressed for increasing electric current density (J). The experimental results are investigated using numerical modeling of the self-heating process, which elucidates the relative contributions of the asymmetric thermoelectric Thomson heat (∼J) and symmetric Joule heating (∼J2) that lead to symmetric heating for higher current levels. These results are applied in modeling of the self-heating process in phase-change memory devices. While, phase-change memory devices show a clearly preferred operation polarity due to thermoelectric effects, nearly symmetric operation can be achieved with higher amplitude and shorter current pulses, which can lead to design of improved polarity-invariant memory circuitry.
An indirect electric field-induced control in directional migration of rat mesenchymal stem cells
Authors: Park Hyoun-Hyang , Jo Sungkwon , Hoon Seo Cheong , Jeong Je Hoon , Yoo Yeong-Eun , Lee Dae Hoon
Published: December 2014

We present the efficacy of an indirect E-field on the directional migration of rat mesenchymal stem cell (MSC). To avoid current flow through culture media and cell, E-fields were generated without exposing electrodes directly to the cell media. MSC migration was observed during wound closure in presence of indirect E-field. MSC migration depended on the E-field strength and occurs predominantly in the anodal direction. Indirect E-field therapy proved as tentative tool for controlled cell movement and healing.
Near-field NanoThermoMechanical memory
Authors: Elzouka Mahmoud , Ndao Sidy
Published: December 2014

In this letter, we introduce the concept of NanoThermoMechanical Memory. Unlike electronic memory, a NanoThermoMechanical memory device uses heat instead of electricity to record, store, and recover data. Memory function is achieved through the coupling of near-field thermal radiation and thermal expansion resulting in negative differential thermal resistance and thermal latching. Here, we demonstrate theoretically via numerical modeling the concept of near-field thermal radiation enabled negative differential thermal resistance that achieves bistable states. Design and implementation of a practical silicon based NanoThermoMechanical memory device are proposed along with a study of its dynamic response under write/read cycles. With more than 50% of the world's energy losses being in the form of heat along with the ever increasing need to develop computer technologies which can operate in harsh environments (e.g., very high temperatures), NanoThermoMechanical memory and logic devices may hold the answer.
Si concentration dependence of structural inhomogeneities in Si-doped AlxGa1−xN/AlyGa1−yN multiple quantum well structures (x = 0.6) and its relationship with internal quantum efficiency
Authors: Kurai Satoshi , Anai Koji , Miyake Hideto , Hiramatsu Kazumasa , Yamada Yoichi
Published: December 2014

We investigated the distribution of luminescence in Si-doped AlxGa1−xN/AlyGa1−yN multiple quantum well (MQW) structures (x = 0.6) with different Si concentrations by cathodoluminescence (CL) mapping combined with scanning electron microscopy. The effects of surface morphology, dark spot density, and full width at half-maximum of spot CL spectra on internal quantum efficiency (IQE) were determined. A flat surface morphology and uniform CL map were observed for Si-doped AlGaN MQWs, in contrast to undoped AlGaN MQW and Si-doped AlGaN with relatively low Al content. The dark spot density in the Si-doped AlGaN MQWs increased exponentially as the Si concentration increased and did not explain the Si concentration dependence of IQE. In contrast, there was a clear correlation between the dark spot density and IQE of the AlGaN MQWs at a constant Si concentration. The emission energy distribution arising from the inhomogeneity of the relative Al content and the well layer thickness was estimated by monochromatic CL measurements, although there was almost no difference in the distribution for different Si concentrations. Therefore, the previously reported dependence of the defect complexes on Si concentration is reflected in the IQE of Si-doped AlGaN MQWs. Defect complexes composed of cation vacancies and impurities rather than dislocations and interfacial quality are the major contributor to the IQE of the Si-doped AlGaN MQWs with different Si concentrations.
Anisotropy of band gap absorption in TlGaSe2 semiconductor by ferroelectric phase transformation
Authors: Gulbinas Karolis , Grivickas Vytautas , Gavryushin Vladimir
Published: December 2014

The depth-resolved free-carrier absorption and the photo-acoustic response are used to examine the band-gap absorption in 2D-TlGaSe2 layered semiconductor after its transformation into the ferroelectric F-phase below 107 K. The absorption exhibits unusual behavior with a biaxial character in respect to the light polarization on the layer plane. A spectral analysis shows that the anisotropy is associated to the lowest Γ-direct optical transition. The Γ-absorption and the localized exciton at 2.11 eV are dipole-prohibited or partially allowed in two nearly perpendicular polarization directions. The shift of anisotropy axis in respect to crystallographic a- and b-directions demonstrates the non-equivalent zigzag rearrangement of the interlayer connecting Tl+ ions, which is responsible for occurrence of the F-phase.
Effect of the nitrogen incorporation and fast carrier dynamics in (In,Ga)AsN/GaP self-assembled quantum dots
Authors: Gauthier J.-P. , Robert C. , Almosni S. , Léger Y. , Perrin M. , Even J. , Balocchi A. , Carrère H. , Marie X. , Cornet C. , Durand O.
Published: December 2014

We report on the structural and optical properties of (In,Ga)AsN self-assembled quantum dots grown on GaP (001) substrate. A comparison with nitrogen free (In,Ga)As system is presented, showing a clear modification of growth mechanisms and a significant shift of the photoluminescence spectrum. Low temperature carrier recombination dynamics is studied by time-resolved photoluminescence, highlighting a drastic reduction of the characteristic decay-time when nitrogen is incorporated in the quantum dots. Room temperature photoluminescence is observed at 840 nm. These results reveal the potential of (In,Ga)AsN as an efficient active medium monolithically integrated on Si for laser applications.
Non-magnetic organic/inorganic spin injector at room temperature
Authors: Mathew Shinto P. , Mondal Prakash Chandra , Moshe Hagay , Mastai Yitzhak , Naaman Ron
Published: December 2014

Spin injection into solid-state devices is commonly performed by use of ferromagnetic metal electrodes. Here, we present a spin injector design without permanent magnet; rather, the spin selectivity is determined by a chiral tunneling barrier. The chiral tunneling barrier is composed of an ultrathin Al2O3 layer that is deposited on top of a chiral self-assembled monolayer (SAM), which consists of cysteine or oligopeptide molecules. The experimentally observed magnetoresistance can be up to 20% at room temperature, and it displays an uncommon asymmetric curve as a function of the applied magnetic field. These findings show that the spin injector transmits only one spin orientation, independent of external magnetic field. The sign of the magnetoresistance depends on the handedness of the molecules in the SAM, which act as a spin filter, and the magnitude of the magnetoresistance depends only weakly on temperature.
Phylogenetic relationships within the flatworm genus Choeradoplana Graff (Platyhelminthes : Tricladida) inferred from molecular data with the description of two new sympatric species from Araucaria moist forests
Authors: Lemos V. S. , Cauduro G. P. , Valiati V. H. , Leal-Zanchet A. M.
Published: December 2014

The genus Choeradoplana encompasses 11 species, nine of which have a restricted distribution and are only known from their type localities. Herein we describe two new species of Choeradoplana from Araucaria moist forests, C. minima, sp. nov. Lemos & Leal-Zanchet and C. benyai, sp. nov. Lemos & Leal-Zanchet, based on morphological and molecular data, and use two molecular markers to investigate their phylogenetic relationships with other species in the genus, including its type species. Both morphological and molecular analyses clearly distinguish C. minima, sp. nov., C. benyai, sp. nov. and C. iheringi. The analyses of the ITS-1, COI and sequence divergence data also indicated that C. benyai, sp. nov. is more closely related to the type species of the genus, C. iheringi, than to C. minima, sp. nov. The three species are sympatric in Araucaria moist forest areas of the São Francisco de Paula National Forest; C. minima, sp. nov. and C. benyai, sp. nov. seem to be endemic to their type localities. Regarding external morphology, C. benyai, sp. nov. and C. iheringi could be considered cryptic species, only distinguishable on the basis of the copulatory apparatus. However, immature specimens of C. benyai, sp. nov. and C. iheringi could only be identified based on molecular data. Our results demonstrate that COI should be used with caution for reconstructing phylogenies, and other slower-evolving nuclear genes are a feasible alternative for resolving some of the phylogenetic relationships.
Cyclical change in Hungarian comparatives
Authors: Bacskai-Atkari Julia
Published: December 2014

This paper examines cyclical changes in comparative subclauses, showing how operators are reanalysed as complementisers via the general mechanism of the relative cycle, and how this is related to whether certain lexical elements have to be deleted at the left periphery. I also show that only operators appearing without a lexical XP can be grammaticalised, which follows from the nature of the formal features associated with the various operator elements. Though the main focus is on Hungarian historical data, the framework can be applied to other languages too, such as German and Italian, since the changes stem from general principles of economy.
The development of addressee agreement on demonstratives
Authors: Souag Lameen
Published: December 2014

The person-oriented nature of a demonstrative system can be marked explicitly by incorporating person markers into demonstratives. When these distinguish gender or number, this can lead to an unusual type of allocutivity: addressee agreement on medials. The latter development is cross-linguistically rarely reported, but is attested in Siwi Berber, Quranic and Rāziħ Arabic and arguably Imperial Aramaic. Examination of these and other languages shows a pathway whereby demonstrative systems gain addressee-anchored terms through grammaticalisation of a phrase including an oblique second person pronoun, occasionally producing addressee agreement. The semantic properties of allocutivity help explain the rarity of the latter result.
The Arab regional system: a question of survival
Authors: Dessouki Ali El Deen Hillal
Published: December 2014

It would be a mistake to believe that the Arab regional system (heretofore referred to as the ‘Arab regional system’; ‘the system’ or the ‘regional system’) is endangered by the current instability and upheaval affecting the Arab region, and that the threats that currently loom over it are new and unlike anything that have previously been faced. It would be equally erroneous to believe that the current dangers and threats are merely a repetition of what the system has experienced before and was able to confront and deal with. To say that the Arab regional system is a ‘product of struggle’ that originated and developed amid the successive waves of internal conflict between the countries that it comprises and the external clashes with other regional and international powers would not be an exaggeration. Up to now the Arab regional system has disproved all the analyses that predicted its death, beginning with Fouad Ajami’s famous studies entitled “The End of Pan Arabism” (1978/79, in Foreign Affairs 57 (2): 355– 373) and The Arab Predicament: Arab Political Thought and Practice since 1967 (1992, Cambridge University Press) to Burhan Ghalioun’s article for Al Jazeera (“Nihayah al-nizam al-iqlimi al-’arabi” [The end of the Arab regional system]. Al Jazeera, 10 March 2004), just as it proved its ability to contain the threats it faced and to adapt to them. The reason for its survival is primarily attributable to a unique feature that distinguishes it from other regional systems; this feature combines two characteristics: geographical continuity between a group of neighbouring states (with the exception of Somalia and the Comoros Islands), and linguistic homogeneity, cultural affinity and a sense of belonging to a common space of civilization and culture, while simultaneously acknowledging the existence of diversity and distinctive particularities. The question arises today as to whether the Arab regional system can continue to sustain itself successfully, or whether the present challenges and threats it now faces are of a new kind that go beyond the capabilities of its institutions and member states? Within this context, this opinion and position paper focuses on the author’s point of view and the essential factors supporting it. It does not present, discuss or critic the views of others. The paper is divided into three parts: the first describes the origin of the Arab regional system and its development in the heart of struggle; the second describes the new factors that endanger and challenge the status quo; and the third proposes scenarios for the future of the Arab system.
Depth Related Distribution of Postjuvenile Red Snapper in Southeastern U.S. Atlantic Ocean Waters: Ontogenic Patterns and Implications for Management
Authors: Mitchell Warren A. , Kellison G. Todd , Bacheler Nathan M. , Potts Jennifer C. , Schobernd Christina M. , Hale Loraine F.
Published: December 2014

For the economically and ecologically important Red Snapper Lutjanus campechanus, depth distribution patterns across ontogeny are not well understood, particularly in the southeastern U.S. Atlantic Ocean (SEUSA). Using data derived from two fishery independent surveys targeting hardbottom habitats, we examined patterns of age and length specific depth distributions of postjuvenile (age 1+) Red Snapper in the SEUSA. We also compared age and length distributions between fishery independent surveys and commercial hook and line catches to make inferences about gear specific age and size selectivity, which could have implications for gear specific interpretations of Red Snapper depth distribution patterns and for determining selectivity functions used in stock assessments. Older, larger Red Snapper were generally distributed throughout all depths, whereas the younger and smaller Red Snapper occurred disproportionately in relatively shallow waters. For Red Snapper equal to or larger than 50 cm FL, we found no evidence of a positive relationship between depth and age or length. Additionally, age and length distributions of Red Snapper ≥ 50 cm FL did not differ between fishery independent surveys and the commercial hook and line fishery. These results provide no support for assertions of greater abundances of older and larger Red Snapper in deeper SEUSA waters. As observed in this study for Red Snapper in SEUSA waters, we suggest that patterns of increasing age and size with depth for multiple reef associated fish species in SEUSA and Gulf of Mexico waters may be driven by younger and smaller fish occurring in shallower waters, and older and larger fish being distributed more equally across depths. Analyses to test this hypothesis for multiple species would be informative for their assessment and management and are recommended.

Received October 21, 2013; accepted March 11, 2014
PrimerDesign-M: a multiple-alignment based multiple-primer design tool for walking across variable genomes
Authors: Yoon Hyejin , Leitner Thomas
Published: December 2014

Summary: Analyses of entire viral genomes or mtDNA requires comprehensive design of many primers across their genomes. Furthermore, simultaneous optimization of several DNA primer design criteria may improve overall experimental efficiency and downstream bioinformatic processing. To achieve these goals, we developed PrimerDesign-M. It includes several options for multiple-primer design, allowing researchers to efficiently design walking primers that cover long DNA targets, such as entire HIV-1 genomes, and that optimizes primers simultaneously informed by genetic diversity in multiple alignments and experimental design constraints given by the user. PrimerDesign-M can also design primers that include DNA barcodes and minimize primer dimerization. PrimerDesign-M finds optimal primers for highly variable DNA targets and facilitates design flexibility by suggesting alternative designs to adapt to experimental conditions.

Availability and implementation: PrimerDesign-M is available as a webtool at http://www.hiv.lanl.gov/content/sequence/PRIMER_DESIGN/primer_design.html

Contact:  tkl@lanl.gov or seq-info@lanl.gov.
Transmitted HIV drug resistance at the Thai Red Cross Anonymous Clinic in Bangkok: results from three consecutive years of annual surveillance
Authors: Sirivichayakul Sunee , Kantor Rami , DeLong Allison K. , Wongkunya Rapeeporn , Mekprasan Suwanna , Ruxrungtham Kiat , Sohn Annette H. , Phanuphak Praphan
Published: December 2014

Objectives

The aim of this study was to prospectively survey transmitted drug resistance (TDR) among recently infected individuals (mostly MSM).

Methods

TDR was determined in prospective annual cohorts of recently HIV-1-infected individuals consecutively recruited from 2008 to 2010. Resistance interpretation was carried out using Stanford Database tools and the WHO surveillance drug resistance mutation list. Kruskal–Wallis and Fisher's exact tests were used to compare demographic and laboratory outcomes.

Results

A total of 299 subjects were enrolled, with 89% MSM. Median viral load was significantly higher in 2010 than in 2008 (P = 0.004). Of the 284 analysable reverse transcriptase/protease sequences, TDR to any drug was found in 14/284 (4.9%); 4.0% in 2008, 5.9% in 2009 and 5.3% in 2010, with an increasing trend of TDR to NRTIs and NNRTIs from 2008 to 2010 (P = 0.07). Good correlation was found between our data and the WHO threshold surveillance method. Only rilpivirine had significantly higher (P < 0.05) predicted resistance in 2010 than in 2008 and 2009.

Conclusions

A trend towards an increase in TDR in Thailand where the major epidemic is among MSM was observed, but did not reach the WHO-defined high-level threshold (>15%). Attention to prevent the development and spread of drug resistance is needed.
Monotherapy with boosted PIs as an ART simplification strategy in clinical practice
Authors: Santos José R. , Llibre Josep M. , Berrio-Galan Daniel , Bravo Isabel , Miranda Cristina , Pérez-Alvarez Susana , Pérez-Alvarez Nuria , Paredes Roger , Clotet Bonaventura , Moltó José
Published: December 2014

Background

Data on the efficacy of simplifying therapy using darunavir/ritonavir and lopinavir/ritonavir monotherapy in clinical practice remain limited.

Methods

A retrospective single-centre study including patients initiating darunavir/ritonavir or lopinavir/ritonavir monotherapy with a plasma HIV-1 viral load (pVL) <50 copies/mL and at least one subsequent follow-up visit. The primary endpoint was the percentage of patients remaining free of virological failure (VF; defined as a confirmed pVL >50 copies/mL or as any change in the regimen after a single determination with a pVL >50 copies/mL) during the follow-up. We also evaluated the percentage of patients remaining free of treatment failure (TF; defined as VF or the early discontinuation of monotherapy for any reason) and compared the effectiveness of the two regimens. Effectiveness was evaluated using cumulative survival analysis (at Weeks 48 and 96). Factors associated with VF and TF were analysed using Cox regression.

Results

A total of 522 patients were included (309 receiving lopinavir/ritonavir and 213 receiving darunavir/ritonavir). The median follow-up was 64.3 (30.5–143.0) weeks. The percentage of patients free of VF and TF was 94% (95% CI 91%–96%) and 79% (95% CI 75%–82%) at 48 weeks, respectively, and 86% (95% CI 81%–89%) and 62% (95% CI 57%–67%) at 96 weeks, respectively. The risk of VF was similar for the two regimens (HR = 1.0, 95% CI 0.6–1.8; P = 0.962). Lopinavir/ritonavir monotherapy was associated with a 1.5-fold greater risk of TF (95% CI 1.1–2.1; P = 0.012) and a 2.3-fold greater risk of discontinuation of therapy due to adverse events (95% CI 1.3–3.9; P = 0.003).

Conclusions

The virological efficacy of darunavir/ritonavir and lopinavir/ritonavir monotherapy is high in clinical practice. Treatment discontinuation due to safety issues is more frequent with lopinavir/ritonavir.
Nature or nurture of coplanar Tatooines: the aligned circumbinary Kuiper belt analogue around HD 131511
Authors: Kennedy Grant M.
Published: December 2014

A key discovery of the Kepler mission is of the circumbinary planets known as ‘Tatooines’, which appear to be well aligned with their host stars’ orbits. Whether this alignment is due to initially coplanar circumbinary planet-forming discs (i.e. nature), or subsequent alignment of initially misaligned discs by warping the inner disc or torquing the binary (i.e. nurture), is not known. Tests of which scenario dominates may be possible by observing circumbinary Kuiper belt analogues (‘debris discs’), which trace the plane of the primordial disc. Here, the 140 au diameter circumbinary debris disc around HD 131511 is shown to be aligned to within 10° of the plane of the near edge-on 0.2 au binary orbit. The stellar equator is also consistent with being in this plane. If the primordial disc was massive enough to pull the binary into alignment, this outcome should be common and distinguishing nature versus nurture will be difficult. However, if only the inner disc becomes aligned with the binary, the HD 131511 system was never significantly misaligned. Given an initial misalignment, the ∼ Gyr main-sequence lifetime of the star allows secular perturbations to align the debris disc out to 100 au at the cost of an increased scaleheight. The observed debris disc scaleheight limits any misalignment to less than 25°. With only a handful known, many more such systems need to be characterized to help test whether the alignment of circumbinary planets is nature or nurture.
Mechanical properties of the cement of the stalked barnacleDosima fascicularis(Cirripedia, Crustacea)
Authors: Zheden Vanessa , Klepal Waltraud , Gorb Stanislav N. , Kovalev Alexander
Published: December 2014

The stalked barnacleDosima fascicularissecretes foam-like cement, the amount of which usually exceeds that produced by other barnacles. WhenDosimasettles on small objects, this adhesive is additionally used as a float which gives buoyancy to the animal. The dual use of the cement byD. fascicularisrequires mechanical properties different from those of other barnacle species. In the float, two regions with different morphological structure and mechanical properties can be distinguished. The outer compact zone with small gas-filled bubbles (cells) is harder than the interior one and forms a protective rind presumably against mechanical damage. The inner region with large, gas-filled cells is soft. This study demonstrates thatD. fasciculariscement is soft and visco-elastic. We show that the values of the elastic modulus, hardness and tensile stress are considerably lower than in the rigid cement of other barnacles.
RBFOX and PTBP1 proteins regulate the alternative splicing of micro-exons in human brain transcripts
Authors: Li Yang I. , Sanchez-Pulido Luis , Haerty Wilfried , Ponting Chris P.
Published: December 2014

Ninety-four percent of mammalian protein-coding exons exceed 51 nucleotides (nt) in length. The paucity of micro-exons (≤ 51 nt) suggests that their recognition and correct processing by the splicing machinery present greater challenges than for longer exons. Yet, because thousands of human genes harbor processed micro-exons, specialized mechanisms may be in place to promote their splicing. Here, we survey deep genomic data sets to define 13,085 micro-exons and to study their splicing mechanisms and molecular functions. More than 60% of annotated human micro-exons exhibit a high level of sequence conservation, an indicator of functionality. While most human micro-exons require splicing-enhancing genomic features to be processed, the splicing of hundreds of micro-exons is enhanced by the adjacent binding of splice factors in the introns of pre-messenger RNAs. Notably, splicing of a significant number of micro-exons was found to be facilitated by the binding of RBFOX proteins, which promote their inclusion in the brain, muscle, and heart. Our analyses suggest that accurate regulation of micro-exon inclusion by RBFOX proteins and PTBP1 plays an important role in the maintenance of tissue-specific protein–protein interactions.
Crystal structure of 5-[bis(methylsulfonyl)methyl]-1,3-dimethyl-5-(methylsulfonyl)pyrimidine-2,4,6(1H,3H,5H)-trione
Authors: Mallah Eyad , Al-Sheikh Ahmed , Sweidan Kamal , Abu Dayyih Wael , Steimann Manfred
Published: December 2014

In the title compound, C10H16N2O9S3, the pyrimidine ring of the 1,3-dimethyl barbituric acid moiety has an envelope conformation with the C atom carrying the methylsulfonyl and bis(methylsulfonyl)methyl substituents as the flap. The dihedral angle between mean plane of the pyrimidine ring and the S/C/S plane is 72.4 (3)°. In the crystal, molecules are linkedviaC—H...O hydrogen bonds, forming a three-dimensional structure.