bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of suprathermal electrons during nanosecond laser energy deposit in fused silica
Authors: Grua P. , Hébert D. , Lamaignère L. , Rullier J.-L.
Published: August 2014

An accurate description of interaction between a nanosecond laser pulse and a wide band gap dielectric, such as fused silica, requires the understanding of energy deposit induced by temperature changes occurring in the material. In order to identify the fundamental processes involved in laser-matter interaction, we have used a 1D computational model that allows us to describe a wide set of physical mechanisms and intended for comparison with specially designed “1D experiments.” We have pointed out that suprathermal electrons are very likely implicated in heat conduction, and this assumption has allowed the model to reproduce the experiments.
Suns-VOC characteristics of high performance kesterite solar cells
Authors: Gunawan Oki , Gokmen Tayfun , Mitzi David B.
Published: August 2014

Low open circuit voltage (VOC) has been recognized as the number one problem in the current generation of Cu2ZnSn(Se,S)4 (CZTSSe) solar cells. We report high light intensity and low temperature Suns-VOC measurement in high performance CZTSSe devices. The Suns-VOC curves exhibit bending at high light intensity, which points to several prospective VOC limiting mechanisms that could impact the VOC, even at 1 sun for lower performing samples. These VOC limiting mechanisms include low bulk conductivity (because of low hole density or low mobility), bulk or interface defects, including tail states, and a non-ohmic back contact for low carrier density CZTSSe. The non-ohmic back contact problem can be detected by Suns-VOC measurements with different monochromatic illuminations. These limiting factors may also contribute to an artificially lower JSC-VOC diode ideality factor.
Cluster altered magnetic and transport properties in Ge1−x−yMnxEuyTe
Authors: Kilanski L. , Górska M. , Szymczak R. , Dobrowolski W. , Podgórni A. , Avdonin A. , Domukhovski V. , Slynko V. E. , Slynko E. I.
Published: August 2014

Magnetic and transport properties of Ge1−x−yMnxEuyTe crystals with chemical compositions 0.041 ≤ x ≤ 0.092 and 0.010 ≤ y ≤ 0.043 are studied. Ferromagnetic order is observed at 150 < T < 160 K. Aggregation of magnetic ions into clusters is found to be the source of almost constant, composition independent Curie temperatures in our samples. Magnetotransport studies show that below 25 K there is a negative magnetoresistance, which is not linear and has a minimum and above 60 K the magnetoresistance is positive and linear. Negative magnetoresistance detected at T < 25 K is found to be due to a tunneling of spin-polarized electrons between ferromagnetic clusters. A linear positive magnetoresistance is identified to be a geometrical effect related to the presence of ferromagnetic clusters inside the semiconductor matrix. The product of the polarization constant (P) and the inter-grain exchange constant (J), JP, varies between about 0.13 meV and 0.99 meV. A strong anomalous Hall effect is observed for T ≤ TC, where TC is the Curie temperature, with coefficients RS independent of temperature. The scaling analysis of the AHE leads to a conclusion that this effect is due to a skew scattering mechanism.
Electron cyclotron beam measurement system in the Large Helical Device
Authors: Kamio S. , Takahashi H. , Kubo S. , Shimozuma T. , Yoshimura Y. , Igami H. , Ito S. , Kobayashi S. , Mizuno Y. , Okada K. , Osakabe M. , Mutoh T.
Published: August 2014

In order to evaluate the electron cyclotron (EC) heating power inside the Large Helical Device vacuum vessel and to investigate the physics of the interaction between the EC beam and the plasma, a direct measurement system for the EC beam transmitted through the plasma column was developed. The system consists of an EC beam target plate, which is made of isotropic graphite and faces against the EC beam through the plasma, and an IR camera for measuring the target plate temperature increase by the transmitted EC beam. This system is applicable to the high magnetic field (up to 2.75 T) and plasma density (up to 0.8 × 1019 m−3). This system successfully evaluated the transmitted EC beam profile and the refraction.
Linearly polarized single photon antibunching from a site-controlled InGaN quantum dot
Authors: Jemsson Tomas , Machhadani Houssaine , Karlsson K. Fredrik , Hsu Chih-Wei , Holtz Per-Olof
Published: August 2014

We report on the observation of linearly polarized single photon antibunching in the excitonic emission from a site-controlled InGaN quantum dot. The measured second order coherence function exhibits a significant dip at zero time difference, corresponding to gm2(0)=0.90 under continuous laser excitation. This relatively high value of gm2(0) is well understood by a model as the combination of short exciton life time (320 ps), limited experimental timing resolution and the presence of an uncorrelated broadband background emission from the sample. Our result provides the first rigorous evidence of InGaN quantum dot formation on hexagonal GaN pyramids, and it highlights a great potential in these dots as fast polarized single photon emitters if the background emission can be eliminated.
Largely enhanced electromechanical properties of BaTiO3-(Na0.5Er0.5)TiO3 lead-free piezoelectric ceramics
Authors: Li Jun , Chai Xiaona , Peng Dengfeng , Zou Hua , Wang Xusheng , Yao Xi
Published: August 2014

Lead-free (1 − x)BaTiO3-x(Na0.5Er0.5)TiO3 (0 ≤ x ≤ 0.15) ceramics were prepared by a solid state reaction method. Their structure and electric properties were analyzed. Rietveld refinements suggested that the ceramics crystallized in the tetragonal perovskite space group P4 mm at room temperature. With increasing x from 0 to 0.05, Na+/Er3+ co-substitution at Ba-site in BaTiO3 leads to the decrease of lattice parameters and unit cell volume. While minor secondary phase, Er2Ti2O7 and (TiO1.2)0.787, appears at x = 0.10 or above. A great enhancement of piezoelectric properties and other electric parameters was obtained in this system by properly moderating the compositions. For example, in the ceramics with composition x = 0.05, a large piezoelectric coefficient d33 (333 pm/V), a high remnant polarization Pr (14.3 μC/cm2), a good planar electromechanical coupling factor kp (0.391), a mechanical quality factor Qm (97.3), and a high Curie temperature (TC = 134 °C) (higher than that of pure BaTiO3) were achieved. Our results show that (1 − x)BaTiO3-x(Na0.5Er0.5)TiO3 ceramics are a good candidate of lead-free piezoelectric materials.
Inverse time-of-flight spectrometer for beam plasma research
Authors: Yushkov Yu. G. , Oks E. M. , Zolotukhin D. B. , Tyunkov A. V. , Savkin K. P.
Published: August 2014

The paper describes the design and principle of operation of an inverse time-of-flight spectrometer for research in the plasma produced by an electron beam in the forevacuum pressure range (5–20 Pa). In the spectrometer, the deflecting plates as well as the drift tube and the primary ion beam measuring system are at high potential with respect to ground. This provides the possibility to measure the mass-charge constitution of the plasma created by a continuous electron beam with a current of up to 300 mA and electron energy of up to 20 keV at forevacuum pressures in the chamber placed at ground potential. Research results on the mass-charge state of the beam plasma are presented and analyzed.
Towards large size substrates for III-V co-integration made by direct wafer bonding on Si
Authors: Daix N. , Uccelli E. , Czornomaz L. , Caimi D. , Rossel C. , Sousa M. , Siegwart H. , Marchiori C. , Hartmann J. M. , Shiu K.-T. , Cheng C.-W. , Krishnan M. , Lofaro M. , Kobayashi M. , Sadana D. , Fompeyrine J.
Published: August 2014

We report the first demonstration of 200 mm InGaAs-on-insulator (InGaAs-o-I) fabricated by the direct wafer bonding technique with a donor wafer made of III-V heteroepitaxial structure grown on 200 mm silicon wafer. The measured threading dislocation density of the In0.53Ga0.47As (InGaAs) active layer is equal to 3.5 × 109 cm−2, and it does not degrade after the bonding and the layer transfer steps. The surface roughness of the InGaAs layer can be improved by chemical-mechanical-polishing step, reaching values as low as 0.4 nm root-mean-square. The electron Hall mobility in 450 nm thick InGaAs-o-I layer reaches values of up to 6000 cm2/Vs, and working pseudo-MOS transistors are demonstrated with an extracted electron mobility in the range of 2000–3000 cm2/Vs. Finally, the fabrication of an InGaAs-o-I substrate with the active layer as thin as 90 nm is achieved with a Buried Oxide of 50 nm. These results open the way to very large scale production of III-V-o-I advanced substrates for future CMOS technology nodes.
Development of bulk-type all-solid-state lithium-sulfur battery using LiBH4 electrolyte
Authors: Unemoto Atsushi , Yasaku Syun , Nogami Genki , Tazawa Masaru , Taniguchi Mitsugu , Matsuo Motoaki , Ikeshoji Tamio , Orimo Shin-ichi
Published: August 2014

Stable battery operation of a bulk-type all-solid-state lithium-sulfur battery was demonstrated by using a LiBH4 electrolyte. The electrochemical activity of insulating elemental sulfur as the positive electrode was enhanced by the mutual dispersion of elemental sulfur and carbon in the composite powders. Subsequently, a tight interface between the sulfur-carbon composite and the LiBH4 powders was manifested only by cold-pressing owing to the highly deformable nature of the LiBH4 electrolyte. The high reducing ability of LiBH4 allows using the use of a Li negative electrode that enhances the energy density. The results demonstrate the interface modification of insulating sulfur and the architecture of an all-solid-state Li-S battery configuration with high energy density.
Blinking suppression of CdTe quantum dots on epitaxial graphene and the analysis with Marcus electron transfer
Authors: Hirose Takuya , Kutsuma Yasunori , Kurita Atsusi , Kaneko Tadaaki , Tamai Naoto
Published: August 2014

We have prepared epitaxial graphene by a Si sublimation method from 4H-SiC. Single-particle spectroscopy of CdTe quantum dots (QDs) on epitaxial graphene covered with polyvinylpyrrolidone (PVP) or polyethylene glycol (PEG) showed the suppression of luminescence blinking and ∼10 times decreased luminescence intensity as compared with those on a glass. The electronic coupling constant, H01, between CdTe QDs and graphene was calculated to be (3.3 ± 0.4) × 102 cm−1 in PVP and (3.7 ± 0.8) × 102 cm−1 in PEG based on Marcus theory of electron transfer and Tang-Marcus model of blinking with statistical distribution.
Luminescence properties and scintillation response in Ce3+-doped Y2Gd1Al5-xGaxO12 (x = 2, 3, 4) single crystals
Authors: Chewpraditkul Warut , Pánek Dalibor , Brůža Petr , Chewpraditkul Weerapong , Wanarak Chalerm , Pattanaboonmee Nakarin , Babin Vladimir , Bartosiewicz Karol , Kamada Kei , Yoshikawa Akira , Nikl Martin
Published: August 2014

The compositional dependence of luminescence properties and scintillation response were investigated in Ce3+-doped Y2Gd1Al5-xGaxO12 (x = 2, 3, 4) single crystals. The Gd3+ → Ce3+ energy transfer was evidenced by photoluminescence excitation spectra of Ce3+ emission. With increasing Ga content in the garnet host, the Ce3+ luminescence from the lowest 5d level (5d1) is shifted toward higher energy due to the decrease in the crystal field splitting of the 5d levels. Light yield (LY) and its dependence on the amplifier shaping time were measured under excitation with γ-rays. High LY value of ∼38 000 ph/MeV was obtained for a Y2Gd1Al3Ga2O12:Ce sample. Scintillation decay was measured with an extended dynamical and temporal scale under the nanosecond pulse soft X-ray excitation. The decrease of both LY value and relative contribution of slower decay component in the scintillation response was observed with increasing Ga content in the garnet host.
Electrodeposition of InSb branched nanowires: Controlled growth with structurally tailored properties
Authors: Das Suprem R. , Akatay Cem , Mohammad Asaduzzaman , Khan Mohammad Ryyan , Maeda Kosuke , Deacon Russell S. , Ishibashi Koji , Chen Yong P. , Sands Timothy D. , Alam Muhammad A. , Janes David B.
Published: August 2014

In this article, electrodeposition method is used to demonstrate growth of InSb nanowire (NW) arrays with hierarchical branched structures and complex morphology at room temperature using an all-solution, catalyst-free technique. A gold coated, porous anodic alumina membrane provided the template for the branched NWs. The NWs have a hierarchical branched structure, with three nominal regions: a “trunk” (average diameter of 150 nm), large branches (average diameter of 100 nm), and small branches (average diameter of sub-10 nm to sub-20 nm). The structural properties of the branched NWs were studied using scanning transmission electron microscopy, transmission electron microscopy, scanning electron microscopy, x-ray diffraction, energy dispersive x-ray spectroscopy, and Raman spectroscopy. In the as-grown state, the small branches of InSb NWs were crystalline, but the trunk regions were mostly nanocrystalline with an amorphous boundary. Post-annealing of NWs at 420 °C in argon produced single crystalline structures along ⟨311⟩ directions for the branches and along ⟨111⟩ for the trunks. Based on the high crystallinity and tailored structure in this branched NW array, the effective refractive index allows us to achieve excellent antireflection properties signifying its technological usefulness for photon management and energy harvesting.
Thermodynamic insight into spontaneous hydration and rapid water permeation in aquaporins
Authors: Barati Farimani A. , Aluru N. R. , Tajkhorshid Emad
Published: August 2014

We report here a detailed thermodynamic description of water molecules inside a biological water channel. Taking advantage of high-resolution molecular dynamics trajectories calculated for an aquaporin (AQP) channel, we compute the spatial translational and rotational components of water diffusion and entropy in AQP. Our results reveal that the spontaneous filling and entry of water into the pore in AQPs are driven by an entropic gain. Specifically, water molecules exhibit an elevated degree of rotational motion inside the pore, while their translational motion is slow compared with bulk. The partial charges of the lining asparagine residues at the conserved signature Asn-Pro-Ala motifs play a key role in enhancing rotational diffusion and facilitating dipole flipping of water inside the pore. The frequencies of the translational and rotational motions in the power spectra overlap indicating a strong coupling of these motions in AQPs. A shooting mechanism with diffusive behavior is observed in the extracellular region which might be a key factor in the fast conduction of water in AQPs.
Band filling effects on temperature performance of intermediate band quantum wire solar cells
Authors: Kunets Vas. P. , Furrow C. S. , Ware M. E. , de Souza L. D. , Benamara M. , Mortazavi M. , Salamo G. J.
Published: August 2014

Detailed studies of solar cell efficiency as a function of temperature were performed for quantum wire intermediate band solar cells grown on the (311)A plane. A remotely doped one-dimensional intermediate band made of self-assembled In0.4Ga0.6As quantum wires was compared to an undoped intermediate band and a reference p-i-n GaAs sample. These studies indicate that the efficiencies of these solar cells depend on the population of the one-dimensional band by equilibrium free carriers. A change in this population by free electrons under various temperatures affects absorption and carrier transport of non-equilibrium carriers generated by incident light. This results in different efficiencies for both the doped and undoped intermediate band solar cells in comparison with the reference GaAs p-i-n solar cell device.
Modification of quasi-streamwise vortical structure in a drag-reduced turbulent channel flow with spanwise wall oscillation
Authors: Yakeno Aiko , Hasegawa Yosuke , Kasagi Nobuhide
Published: August 2014

The conditional averaging technique is applied to quasi-streamwise vortices in order to clarify the impact of their structural modification on the resultant drag reduction effect in a turbulent channel flow subjected to spanwise harmonic wall oscillation. The quantitative contributions of quadrant Reynolds shear stresses induced by the quasi-streamwise vortices are calculated on the basis of the Fukagata-Iwamoto-Kasagi identity [K. Fukagata, K. Iwamoto, and N. Kasagi, “Contribution of Reynolds stress distribution to the skin friction in wall-bounded flows,” Phys. Fluids 14, L73 (2002)]. It is found that the Q2 event characterized by upwelling of low-speed fluid away from the wall governs the skin friction drag reduction at relatively small oscillation periods, whereas the Q4 event characterized by downwelling of high speed fluid toward the wall slightly contributes to drag reduction at small oscillation periods, and then to drag increase significantly with increasing the oscillation period. Detailed investigation of the conditionally averaged velocity field around the detected vortices reveals that the suppression of Q2 occurs at a certain phase when the wall motion is applied so as to oppose the rotation of near-wall streamwise vortices, whereas the enhancement of Q4 at a large oscillation period is caused by spanwise tilting of coherent structures due to the alternating spanwise shear induced by spanwise wall oscillation. Based on these findings, we develop a new predictive correlation for drag reduction effect applicable to a wide range of oscillation periods and amplitudes.
Refillable and magnetically actuated drug delivery system using pear-shaped viscoelastic membrane
Authors: So Hongyun , Seo Young Ho , Pisano Albert P.
Published: August 2014

We report a refillable and valveless drug delivery device actuated by an external magnetic field for on-demand drug release to treat localized diseases. The device features a pear-shaped viscoelastic magnetic membrane inducing asymmetrical deflection and consecutive touchdown motion to the bottom of the dome-shaped drug reservoir in response to a magnetic field, thus achieving controlled discharge of the drug. Maximum drug release with 18 ± 1.5 μg per actuation was achieved under a 500 mT magnetic flux density, and various controlled drug doses were investigated with the combination of the number of accumulated actuations and the strength of the magnetic field.
Strain characterization of fin-shaped field effect transistors with SiGe stressors using nanobeam electron diffraction
Authors: Kim Sun-Wook , Byeon Dae-Seop , Jang Hyunchul , Koo Sang-Mo , Lee Hoo-Jeong , Ko Dae-Hong
Published: August 2014

This study undertook strain analysis on fin-shaped field effect transistor structures with epitaxial Si1−xGex stressors, using nano-beam electron diffraction and finite elements method. Combining the two methods disclosed dynamic strain distribution in the source/drain and channel region of the fin structure, and the effects of dimensional factors such as the stressor thickness and fin width, offering valuable information for device design.
Spin wave localization in one-dimensional magnonic microcavity comprising yttrium iron garnet
Authors: Kanazawa Naoki , Goto Taichi , Inoue Mitsuteru
Published: August 2014

We demonstrate the localization of magnetostatic surface waves, i.e., spin waves, in a one-dimensional magnonic microcavity substantialized with periodical conductivity modulation. The narrow localized state is observed inside band gaps and is responsible for a sharp transmission peak. The experimental results strongly agree with the theoretical prediction made with the shape magnetic anisotropy of the propagating medium composed of yttrium iron garnet taken into account.
Refractive index of erbium doped GaN thin films
Authors: Alajlouni S. , Sun Z. Y. , Li J. , Zavada J. M. , Lin J. Y. , Jiang H. X.
Published: August 2014

GaN is an excellent host for erbium (Er) to provide optical emission in the technologically important as well as eye-safe 1540 nm wavelength window. Er doped GaN (GaN:Er) epilayers were synthesized on c-plane sapphire substrates using metal organic chemical vapor deposition. By employing a pulsed growth scheme, the crystalline quality of GaN:Er epilayers was significantly improved over those obtained by conventional growth method of continuous flow of reaction precursors. X-ray diffraction rocking curve linewidths of less than 300 arc sec were achieved for the GaN (0002) diffraction peak, which is comparable to the typical results of undoped high quality GaN epilayers and represents a major improvement over previously reported results for GaN:Er. Spectroscopic ellipsometry was used to determine the refractive index of the GaN:Er epilayers in the 1540 nm wavelength window and a linear dependence on Er concentration was found. The observed refractive index increase with Er incorporation and the improved crystalline quality of the GaN:Er epilayers indicate that low loss GaN:Er optical waveguiding structures are feasible.
In situ transmission electron microscopy of individual carbon nanotetrahedron/nanoribbon structures in Joule heating
Authors: Masuda Yusuke , Yoshida Hideto , Takeda Seiji , Kohno Hideo
Published: August 2014

Collapse of a carbon nanotube results in the formation of a nanoribbon, and a switching of the collapse direction yields a nanotetrahedron in the middle of a nanoribbon. Here, we report in-situ transmission electron microscopy observations of the behavior of carbon nanotetrahedron/nanoribbon structures during Joule heating to reveal their thermal stability. In addition, we propose that the observed process is related to the formation process of the structure.
Communication: Ab initio study of O4H+: A tracer molecule in the interstellar medium?
Authors: Xavier George D. , Bernal-Uruchurtu Margarita I. , Hernández-Lamoneda Ramón
Published: August 2014

The structure and energetics of the protonated molecular oxygen dimer calculated via ab initio methods is reported. We find structures that share analogies with the eigen and zundel forms for the protonated water dimer although the symmetrical sharing of the proton is more prevalent. Analysis of different fragmentation channels show charge transfer processes which indicate the presence of conical intersections for various states including the ground state. An accurate estimate for the proton affinity of O4 leads to a significantly larger value (5.6 eV) than for O2 (4.4 eV), implying that the reaction \documentclass[12pt]{minimal}\begin{document}${\rm H_3^+}$\end{document}H3+ + O4 → O4H+ + H2 is exothermic by 28 Kcal/mol as opposed to the case of O2 which is nearly thermoneutral. This opens up the possibility of using O4H+ as a tracer molecule for oxygen in the interstellar medium.
Electrical contact for wurtzite GaN microdisks
Authors: Lo Ikai , Wang Ying-Chieh , Hsu Yu-Chi , Shih Cheng-Hung , Pang Wen-Yuan , You Shuo-Ting , Hu Chia-Hsuan , Chou Mitch M. C. , Hsu Gary Z. L.
Published: August 2014

We developed a back processing to fabricate an electrical contact of wurtzite GaN microdisk on transparent p-type GaN template. The interface welding between the GaN microdisk and p-type GaN template produced a very solid and secure epi-film contact for the electrical current passing through, with a resistance of 45.0 KΩ and threshold voltage of 5.9 V. The back processing can resolve the obstacle of electrical contacts for self-assembled wurtzite nano-devices.
Effects of rapid thermal annealing on the electrical properties of the AlGaN/AlN/GaN heterostructure field-effect transistors with Ti/Al/Ni/Au gate electrodes
Authors: Zhao Jingtao , Lin Zhaojun , Luan Chongbiao , Zhou Yang , Yang Ming , Lv Yuanjie , Feng Zhihong
Published: August 2014

In this study, we investigated the electrical properties of the AlGaN/AlN/GaN heterostructure field-effect transistors (HFETs) with Ti/Al/Ni/Au gate electrodes using the measured capacitance-voltage, current-voltage characteristics, and micro-Raman spectroscopy. We found that the uneven distribution of the strain caused by the Schottky metals was a major factor that generates the polarization Coulomb field scattering in AlGaN/AlN/GaN HFETs, and after appropriate rapid thermal annealing (RTA) processes, the polarization Coulomb field scattering was greatly weakened and the two-dimensional electron gas electron mobility was improved. We also found that the Schottky barrier height and the DC characteristics of the devices became better after appropriate RTA. Of course, the electrical performances mentioned above became deteriorated after excessive annealing.
Dynamic excitation of spoof surface plasmon polaritons
Authors: Wan Xiang , Yin Jia Yuan , Zhang Hao Chi , Cui Tie Jun
Published: August 2014

We propose dynamic control to excite spoof surface plasmon polaritons (SPPs) in the microwave frequency. Using switchable devices, the excitation of spoof SPPs can be turned on and off depending on the DC voltages applied on the switchable devices. To demonstrate the dynamic mechanism, a switchable spoof SPP waveguide is proposed and fabricated in the microwave frequency. Both simulation and measurement results show good performances of the dynamic control in exciting spoof SPPs.
An ion-gated bipolar amplifier for ion sensing with enhanced signal and improved noise performance
Authors: Zhang Da , Gao Xindong , Chen Si , Norström Hans , Smith Ulf , Solomon Paul , Zhang Shi-Li , Zhang Zhen
Published: August 2014

This work presents a proof-of-concept ion-sensitive device operating in electrolytes. The device, i.e., an ion-gated bipolar amplifier (IGBA), consists of a modified ion-sensitive field-effect transistor (ISFET) intimately integrated with a vertical bipolar junction transistor for immediate current amplification without introducing additional noise. With the current non-optimized design, the IGBA is already characterized by a 70-fold internal amplification of the ISFET output signal. This signal amplification is retained when the IGBA is used for monitoring pH variations. The tight integration significantly suppresses the interference of the IGBA signal by external noise, which leads to an improvement in signal-to-noise performance compared to its ISFET reference. The IGBA concept is especially suitable for biochips with millions of electric sensors that are connected to peripheral readout circuitry via extensive metallization which may in turn invite external interferences leading to contamination of the signal before it reaches the first external amplification stage.
Rescaling Spatial Planning: Spatial Planning Reforms in Denmark, England, and the Netherlands
Authors: Roodbol-Mekkes Petra H , van den Brink Adri
Published: August 2014

Following a wave of spatial planning reforms at the beginning of the 21st century, a second wave of reforms has recently swept through several European countries. In this study we investigate the significance of these latest developments by analysing the reforms in Denmark, England, and the Netherlands from the perspective of rescaling, the process of redividing tasks, and responsibilities between the various tiers of government. We show that the reasoning behind the new planning systems and the philosophy they were based on were remarkably similar. Typical catchphrases, such as ‘closer to the citizen’ and ‘development-oriented spatial planning’, were used in each of the countries under study. Although the second wave of changes is legitimised by much of the same wording, the changes are significantly different because comprehensive visions on the integrated spatial development at the national and regional level have been almost completely abandoned. The loss of this ‘something more’ seems to impact the core of spatial planning.
Where they are, why they are there, and where they are going: using niche models to assess impacts of disturbance on the distribution of three endemic rare subtropical rainforest trees of Macadamia (Proteaceae) species
Authors: Powell M. , Accad A. , Shapcott A.
Published: August 2014

Species within the Macadamia genus (Proteaceae) are rare and threatened narrowly distributed inhabitants of subtropical lowland rainforests of eastern Australia. Despite their strong cultural links and economic importance as a source of germplasm for the macadamia nut industry, a comprehensive assessment of factors contributing to their conservation status, or the potential impacts of climate change, is lacking. We used maximum entropy models to identify the respective niche of the following three Macadamia species with overlapping extant distributions: M. integrifolia, M. ternifolia and M. tetraphylla. We used model predictions to identify and prioritise respective areas of habitat, together with change in geographic distribution of habitats between 1990 and 2070 climates. Results reveal considerable overlap in the geographic extent of habitat among the three species; however, the extent of current occupation of habitat by any individual species is limited. Relatively high levels of clearing of ecological communities strongly associated with M. integrifolia or M. ternifolia have occurred within the extent of their respective habitats, with M. tetraphylla less affected within the Queensland extent of its range. Response to climate change varies among the three species, with a general trend of shift in respective niche to areas that currently experience relatively high precipitation and lower temperature regimes.
The Influence of Water and Metal Salt on the Transport and Structural Properties of 1-Octyl-3-methylimidazolium Chloride
Authors: Goujon Nicolas , Byrne Nolene , Walsh Tiffany R. , Forsyth Maria
Published: August 2014

The addition of diluents to ionic liquids (ILs) has recently been shown to enhance the transport properties of ILs. In the context of electrolyte design, this enhancement allows the realisation of IL-based electrolytes for metal–air batteries and other storage devices. It is likely that diluent addition not only impacts the viscosity of the IL, but also the ion–ion interactions and structure. Here, we investigate the nano-structured 1-methyl-3-octylimidazolium chloride (OMImCl) with varying water concentrations in the presence of two metal salts, zinc chloride and magnesium chloride. We find that the choice of metal salt has a significant impact on the structure and transport properties of the system; this is explained by the water structuring and destructing properties of the metal salt.
Lessons from long-term predator control: a case study with the red fox
Authors: Kirkwood Roger , Sutherland Duncan R. , Murphy Stuart , Dann Peter
Published: August 2014

Context Predator-control aims to reduce an impact on prey species, but efficacy of long-term control is rarely assessed and the reductions achieved are rarely quantified. Aims We evaluated the changing efficacy of a 58-year-long campaign against red foxes (Vulpes vulpes) on Phillip Island, a 100-km2 inhabited island connected to the Australian mainland via a bridge. The campaign aimed to eliminate the impact of foxes on ground-nesting birds, particularly little penguins (Eudyptula minor). Methods We monitored the success rate of each fox-control technique employed, the level of effort invested if available, demographics of killed foxes, the numbers of penguins killed by foxes and penguin population size. Key results The campaign began as a bounty system that ran for 30 years and was ineffective. It transitioned into a coordinated, although localised, control program from 1980 to 2005 that invested considerable effort, but relied on subjective assessments of success. Early during the control period, baiting was abandoned for less effective methods that were thought to pose fewer risks, were more enjoyable and produced carcasses, a tangible result. Control was aided by a high level of public awareness, by restricted fox immigration, and by a clear, achievable and measurable target, namely, to prevent little penguin predation by foxes. Carcasses did prove valuable for research, revealing the genetic structure and shifts in fox demographics. The failure of the program was evident after scientific evaluation of fox population size and ongoing fox impacts. In 2006, the campaign evolved into an eradication attempt, adopting regular island-wide baiting, and since then, has achieved effective knock-down of foxes and negligible predation on penguins. Conclusions Effective predator control was achieved only after employing a dedicated team and implementing broad-scale baiting. Abandoning widespread baiting potentially delayed effective control for 25 years. Furthermore, both predator and prey populations should be monitored concurrently because the relationship between predator abundance and impact on prey species is not necessarily density dependent. Implications Critical to adopting the best management strategy is evaluating the efficacy of different methods independently of personal and public biases and having personnel dedicated solely to the task.
Ubiquitin E3 ligase Nedd4-1 acts as a downstream target of PI3K/PTEN-mTORC1 signaling to promote neurite growth
Authors: Hsia Hung-En , Kumar Rohit , Luca Rossella , Takeda Michiko , Courchet Julien , Nakashima Jonathan , Wu Shumin , Goebbels Sandra , An Wenlin , Eickholt Britta J. , Polleux Franck , Rotin Daniela , Wu Hong , Rossner Moritz J. , Bagni Claudia , Rhee Jeong-Seop , Brose Nils , Kawabe Hiroshi
Published: August 2014

Significance

Neurons develop processes called neurites to form defined networks. Neurite growth is regulated by many intracellular signaling pathways, among which signaling via phosphatase and tensin homolog (PTEN) is of particular relevance because it controls the translation of a substantial subset of mRNAs that encode proteins with a role in neurite growth. Previous studies indicated that the E3 ubiquitin ligases Nedd4-1 and Nedd4-2 may ubiquitinate and negatively regulate PTEN in various cell types, including
Xenopus laevis
retinal ganglion cells. We report a strikingly inverted scenario, according to which Nedd4s are dispensable for ubiquitination of PTEN in mammalian central nervous system neurons. Instead,
Nedd4-1
mRNA is one of the most important targets of PTEN-dependent signaling in the regulation of neurite growth.
Direct single-molecule observation of calcium-dependent misfolding in human neuronal calcium sensor-1
Authors: Heidarsson Pétur O. , Naqvi Mohsin M. , Otazo Mariela R. , Mossa Alessandro , Kragelund Birthe B. , Cecconi Ciro
Published: August 2014

Significance

Protein misfolding can lead to neurodegeneration. Yet, the mechanistic details of this deleterious phenomenon are largely unknown, as experimental portrayals of the early and reversible molecular events leading to misfolded conformations have so far remained highly limited. Here we use single-molecule optical tweezers to monitor the structural rearrangements leading to misfolded conformations of human neuronal calcium sensor-1, a protein linked to serious neurological disorders. We identified two distinct and calcium-dependent misfolding trajectories originating from an on-pathway folding intermediate. Remarkably for a calcium sensor, pathologically high calcium concentrations impede correct folding by increasing the occupation probabilities of the misfolded states. The results open ostensible links between protein misfolding and calcium dysregulation that could be important in neurodegeneration and its potential inhibition.
New high-resolution computed tomography data of the Taung partial cranium and endocast and their bearing on metopism and hominin brain evolution
Authors: Holloway Ralph L. , Broadfield Douglas C. , Carlson Kristian J.
Published: August 2014

Significance

The Taung Child (
Australopithecus africanus
) has historical and scientific importance in the fossil record as the first and best example of early hominin brain evolution. It was recently proposed that Taung exhibits adaptive morphology (e.g., persistent metopic suture and open anterior fontanelle), permitting important postnatal brain growth late into infancy. As Taung provides the only purported pre-
Homo
fossil evidence for the suggested adaptive mechanism, we test the hypothesis that it displays these features. Using new high-resolution images and in silico exploration, we did not observe the hypothesized form of these features. If delayed metopic suture closure were adaptive, for example, permitting substantial postnatal brain growth and alleviating an obstetric dilemma, there is no evidence this mechanism evolved before
Homo
.
Enterotoxicity of a nonribosomal peptide causes antibiotic-associated colitis
Authors: Schneditz Georg , Rentner Jana , Roier Sandro , Pletz Jakob , Herzog Kathrin A. T. , Bücker Roland , Troeger Hanno , Schild Stefan , Weber Hansjörg , Breinbauer Rolf , Gorkiewicz Gregor , Högenauer Christoph , Zechner Ellen L.
Published: August 2014

Significance

The human gut microbiota is a complex community of microbes with enormous metabolic potential. Recognition of the significance of bacterial metabolites in mediating host interactions and the impact of perturbations of this ecosystem on human health has increased dramatically. Antibiotic therapy eliminates not only pathogens but also some of the commensal enteric microbiota, sometimes leading to inflammation and diarrhea. Understanding how microbial imbalance actually causes disease is challenging. This study reveals how a gut resident is able to cause colitis during penicillin therapy. We show that a pyrrolobenzodiazepine metabolite produced by
Klebsiella oxytoca
directly damages the intestinal epithelium and disrupts its protective barrier function. The enterotoxicity of tilivalline provides a mechanism for antibiotic-induced colitis.
Efficient replication of a paramyxovirus independent of full zippering of the fusion protein six-helix bundle domain
Authors: Brindley Melinda A. , Plattet Philippe , Plemper Richard Karl
Published: August 2014

Significance

Protein-mediated membrane fusion is essential for eukaryotic cell biology. In several major human viral pathogens the full closure of a six-helix bundle (6HB) fusion core structure is considered imperative for the opening of a productive fusion pore. We tested this paradigm by engineering covalently restricted paramyxovirus fusion proteins that are incapable of full 6HB zippering. These proteins remained fusion competent without disruption of the restricting bonds, although fusion activity was reduced. Recombinant virions harboring the engineered fusion proteins confirmed efficient, 6HB closure-independent paramyxovirus entry. We demonstrate that full 6HB zippering does not govern paramyxovirus entry. Our results may extend to other viruses using related fusiogenic glycoproteins and affect the design of antiparamyxovirus strategies targeting virus entry.
Potentially singular solutions of the 3D axisymmetric Euler equations
Authors: Luo Guo , Hou Thomas Y.
Published: August 2014

Significance

Whether infinitely fast spinning vortices can develop in initially smooth, incompressible inviscid flow fields in finite time is one of the most challenging problems in fluid dynamics. Besides being a difficult mathematical question that has remained open for more than 250 years, the problem also attracts great attention in the physics and engineering communities due to its potential connection to the onset of turbulence in viscous flows. This paper attempts to provide an affirmative answer to this long-standing open question from a numerical point of view, by describing a class of rotationally symmetric flows from which infinitely fast spinning vortices can form in finite time. It suggests, after decades of controversies, a promising direction to the resolution of the problem.
Nonlinear conduction via solitons in a topological mechanical insulator
Authors: Chen Bryan Gin-ge , Upadhyaya Nitin , Vitelli Vincenzo
Published: August 2014

Significance

Mechanisms are zero-energy motions that are key to the operation of mechanical devices, from windshield wipers to robotic arms. We built and studied chain-like mechanisms of coupled rigid rotors that are topologically protected, which means that they are not affected by smooth changes in material parameters like their quantum analogues. These prototypes are examples of mechanical structures that we dub topological metamaterials. Their mechanical excitations are nonlinear solitary waves which are topologically protected and yet tunable by changing the geometry of the unit cell. Although the left and right edges of the sample are equivalent in terms of local constraint counting, the solitary waves can start propagating only from the edge singled out by the topological polarization of the chain.
The Two-pore channel (TPC) interactome unmasks isoform-specific roles for TPCs in endolysosomal morphology and cell pigmentation
Authors: Lin-Moshier Yaping , Keebler Michael V. , Hooper Robert , Boulware Michael J. , Liu Xiaolong , Churamani Dev , Abood Mary E. , Walseth Timothy F. , Brailoiu Eugen , Patel Sandip , Marchant Jonathan S.
Published: August 2014

Significance

Two-pore channels (TPCs) are a recently discovered family of endolysosomal ion channels, but their regulation is controversial. By defining the TPC interactome, we provide a community resource that illuminates TPC complex regulation and resolves associations with novel partners and processes. Physical interactions with endolysosomal trafficking regulators predominate, and Rab GTPases impart isoform-specific roles for TPCs in organelle proliferation and cellular pigmentation. These data imply a fundamental role for TPCs in trafficking that augurs significance for disease states exhibiting lysosomal proliferation where TPC dysregulation may drive pathogenesis.
Comparative analysis of pseudogenes across three phyla
Authors: Sisu Cristina , Pei Baikang , Leng Jing , Frankish Adam , Zhang Yan , Balasubramanian Suganthi , Harte Rachel , Wang Daifeng , Rutenberg-Schoenberg Michael , Clark Wyatt , Diekhans Mark , Rozowsky Joel , Hubbard Tim , Harrow Jennifer , Gerstein Mark B.
Published: August 2014

Significance

Pseudogenes have long been considered nonfunctional elements. However, recent studies have shown they can potentially regulate the expression of protein-coding genes. Capitalizing on available functional-genomics data and the finished annotation of human, worm, and fly, we compared the pseudogene complements across the three phyla. We found that in contrast to protein-coding genes, pseudogenes are highly lineage specific, reflecting genome history more so than the conservation of essential biological functions. Specifically, the human pseudogene complement reflects a massive burst of retrotranspositional activity at the dawn of the primates, whereas the worm’s and fly's repertoire reflects a history of deactivated duplications. However, we also observe that pseudogenes across the three phyla have a consistent level of partial activity, with ∼15% being transcribed.
Bacterial formate hydrogenlyase complex
Authors: McDowall Jennifer S. , Murphy Bonnie J. , Haumann Michael , Palmer Tracy , Armstrong Fraser A. , Sargent Frank
Published: August 2014

Significance

The isolation of an active formate hydrogenlyase is a breakthrough in understanding the molecular basis of bacterial hydrogen production. For over 100 years,
Escherichia coli
has been known to evolve H
2
when cultured under fermentative conditions. Glucose is metabolized to formate, which is then oxidized to CO
2
with the concomitant reduction of protons to H
2
by a single complex called formate hydrogenlyase, which had been genetically, but never biochemically, characterized. In this study, innovative molecular biology and electrochemical experiments reveal a hydrogenase enzyme with the unique ability to sustain H
2
production even under high partial pressures of H
2
. Harnessing bacterial H
2
production offers the prospect of a source of fully renewable H
2
energy, freed from any dependence on fossil fuel.
Temporally defined neocortical translation and polysome assembly are determined by the RNA-binding protein Hu antigen R
Authors: Kraushar Matthew L. , Thompson Kevin , Wijeratne H. R. Sagara , Viljetic Barbara , Sakers Kristina , Marson Justin W. , Kontoyiannis Dimitris L. , Buyske Steven , Hart Ronald P. , Rasin Mladen-Roko
Published: August 2014

Significance

The neocortex is an intricate and diverse cellular network in the brain, generating complex thought and voluntary motor behavior. Although recent attention has focused on the genome and transcriptome, our goal is to study the role of posttranscriptional processing and mRNA translation in neocortical development. In this work, we show that the protein components of actively translating ribosomes and their mRNA cargo in the developing neocortex depend on the temporally specific action of an RNA-binding protein, Hu antigen R (HuR). We further show that HuR is required for the development of neocortical neurons and structure. This study contributes to our overall understanding of how the regulation of functional gene expression influences neocortical development.
Diversity and clonal selection in the human T-cell repertoire
Authors: Qi Qian , Liu Yi , Cheng Yong , Glanville Jacob , Zhang David , Lee Ji-Yeun , Olshen Richard A. , Weyand Cornelia M. , Boyd Scott D. , Goronzy Jörg J.
Published: August 2014

Significance

A decline in the diversity of the T-cell receptor repertoire owing to thymic involution has been implicated as causing defective immune responses in the elderly. By applying next-generation sequencing of replicate TCRB libraries from highly purified T-cell subsets, and using nonparametric statistical analysis, we obtain estimates of repertoire richness in the young adult that are higher than previously reported. Although contracting with age, the repertoire remains highly diverse. These data challenge the paradigm that thymic rejuvenation is needed to maintain diversity and prevent immune incompetence in the elderly. However, we observe an increasing inequality of clonal sizes with age even among naïve T cells. This clonal selection could result in biased and possibly autoreactive immune responses.
Design of donecopride, a dual serotonin subtype 4 receptor agonist/acetylcholinesterase inhibitor with potential interest for Alzheimer's disease treatment
Authors: Lecoutey Cédric , Hedou Damien , Freret Thomas , Giannoni Patrizia , Gaven Florence , Since Marc , Bouet Valentine , Ballandonne Céline , Corvaisier Sophie , Malzert Fréon Aurélie , Mignani Serge , Cresteil Thierry , Boulouard Michel , Claeysen Sylvie , Rochais Christophe , Dallemagne Patrick
Published: August 2014

Significance

Targeting more than one molecular cause implied in the pathogenesis of Alzheimer’s disease (AD) with a sole drug is considered a promising challenge, because it may address the numerous failures that recently occurred during clinical trials that were conducted in this area. Donecopride has been designed by us as a multitarget-directed ligand, targeting both serotonin subtype 4 receptor and acetylcholinesterase with excellent in vitro activities. The latter seems able to not only restore the cholinergic neurotransmission altered in AD but also, promote the secretion of a neurotrophic protein that is detrimental to the neurotoxic amyloid-β peptide. With its excellent drugability, donecopride further displayed significant procognitive effects in mice and generated a promising lead for a previously unidentified approach in AD treatment.
RNA-guided endonuclease provides a therapeutic strategy to cure latent herpesviridae infection
Authors: Wang Jianbin , Quake Stephen R.
Published: August 2014

Significance

Latent viral infection is a major obstacle for effective antiviral treatment and presents a continuous risk to the host. The dormant viral genome during latent infection provides few therapeutic targets other than itself for antiviral drug development. This study demonstrates the clearance of latent Epstein–Barr virus genomes in a subpopulation of Burkitt’s lymphoma patient-derived cells with clustered regularly interspaced short palindromic repeat/Cas9 nuclease. Viral genome destruction leads to proliferation arrest and apoptosis in Epstein–Barr virus-infected cells, with no observed cytotoxicity to noninfected cells. Although many hurdles remain before this approach could be used in the clinic, this strategy may lead to a generalized approach to cure latent viral infections.