bluuebunny/crossref_metadata_2025 huggingface dataset:
Predictive model for alignment and deposition of functionalized nanotubes using applied electric field
Authors: Mostafa Mohammad , Banerjee Soumik
Published: June 2014

Myriad applications, including sensors and supercapacitors, employ substrates decorated with patterned carbon nanotubes (CNTs) in order to leverage the significant anisotropy in their properties. In the present study, a unique continuum mechanics based model was developed to predict the alignment and migration timescales of CNTs for realistic lab-scale electrophoretic deposition (EPD), which is a popular technique to create aligned deposits of pristine and functionalized CNTs without embedded catalysts. This model was initially validated based on results from molecular dynamics simulations to check for mutual consistency. EPD is a complex process that involves electrophoretic alignment and migration of CNTs towards the substrate, displacement of solvent molecules from the surface of substrate by overcoming an energy barrier, followed by deposition. We simulated COOH functionalized CNTs of varying length under a range of applied electric fields (1 V/nm to 5 V/nm) to understand the mechanics of electrophoretic alignment and deposition. The dynamics of alignment and deposition were related to the molecular interactions between the various constituents by calculating friction parameters. The results from the parametric study, which is limited to length scales accessible to molecular dynamics simulations, was scaled up to CNTs of micrometer-scale length by comparing the results with solutions to the continuum scale model. The results indicate that the timescale for rotational alignment of realistic CNTs is of the order of seconds and several orders of magnitudes faster compared to the timescale for migration, which is of the order of thousands of seconds for a channel of diameter of 100 μm.
Complex permittivities of breast tumor tissues obtained from cancer surgeries
Authors: Sugitani Takumi , Kubota Shin-ichi , Kuroki Shin-ichiro , Sogo Kenta , Arihiro Koji , Okada Morihito , Kadoya Takayuki , Hide Michihiro , Oda Miyo , Kikkawa Takamaro
Published: June 2014

The variability in measurements of complex permittivities of tumor tissues between multiple samples could be attributed to the volume fraction of cancer cells in the excised tumor tissue. By the use of a digital photomicrograph image and hematoxylin-eosin staining, it was found that the malignant tumor tissue was not fully occupied by the cancer cells, but the cells were distributed locally in the stroma cells depending on the growth of cancer. The results showed that the volume fraction of cancer cells in the tumor tissue had a correlation to the measured conductivity and dielectric constant in the frequency range from 1 GHz to 6 GHz. It introduces a method to understand and gauge variability in measurements between different tumors.
Manipulation of magnetic state in nanostructures by perpendicular anisotropy and magnetic field
Authors: Chen J. P. , Xie Y. L. , Chu P. , Wang Z. Q. , Wang Y. L. , Gao X. S. , Liu J.-M.
Published: June 2014

We investigate the transitions of spin configurations in ultrathin nanostructures by tuning the perpendicular anisotropy (Kz) and out-of-plane magnetic field (H), using the Monte Carlo simulation. It is revealed that enhancing the anisotropy Kz can drive the evolution of in-plane vortex state into intriguing saturated magnetization states under various H, such as the bubble domain state and quadruple-block-domain state etc. The spin configurations of these states exhibit remarkable H-dependence. In addition, the strong effects of geometry and size on the spin configurations of nanostructures are observed. In particular, a series of edged states occur in the circular disk-shaped lattices, and rich intricate saturated magnetization patterns appear in big lattices. It is suggested that the magnetic states can be manipulated by varying the perpendicular anisotropy, magnetic field, and geometry/size of the nanostructures. Furthermore, the stability (retention capacity) of the saturated magnetization states upon varying magnetic field is predicted, suggesting the potential applications of these saturated magnetization states in magnetic field-controlled data storages.
Superior mechanical flexibility of phosphorene and few-layer black phosphorus
Authors: Wei Qun , Peng Xihong
Published: June 2014

Recently, fabricated two dimensional (2D) phosphorene crystal structures have demonstrated great potential in applications of electronics. Mechanical strain was demonstrated to be able to significantly modify the electronic properties of phosphorene and few-layer black phosphorus. In this work, we employed first principles density functional theory calculations to explore the mechanical properties of phosphorene, including ideal tensile strength and critical strain. It was found that a monolayer phosphorene can sustain tensile strain up to 27% and 30% in the zigzag and armchair directions, respectively. This enormous strain limit of phosphorene results from its unique puckered crystal structure. We found that the tensile strain applied in the armchair direction stretches the pucker of phosphorene, rather than significantly extending the P-P bond lengths. The compromised dihedral angles dramatically reduce the required strain energy. Compared to other 2D materials, such as graphene, phosphorene demonstrates superior flexibility with an order of magnitude smaller Young's modulus. This is especially useful in practical large-magnitude-strain engineering. Furthermore, the anisotropic nature of phosphorene was also explored. We derived a general model to calculate the Young's modulus along different directions for a 2D system.
Study of plasma natural convection induced by electron beam in atmosphere
Authors: Deng Yongfeng , Tan Yonghua , Han Xianwei
Published: June 2014

Using high-energy electron beams to ionize air is an effective way to produce a large-size plasma in the atmosphere. In particular, with a steady-state high power generator, some unique phenomena can be achieved, including natural convection of the plasma. The characteristics of this convection are studied both experimentally and numerically. The results show that an asymmetrical temperature field develops with magnitudes that vary from 295 K to 389 K at a pressure of 100 Torr. Natural convection is greatly enhanced under 760 Torr. Nevertheless, plasma transport is negligible in this convection flow field and only the plasma core tends to move upward. Parameter analysis is performed to discern influencing factors on this phenomenon. The beam current, reflecting the Rayleigh number Ra effect, correlates with convection intensity, which indicates that energy deposition is the underlying key factor in determining such convections. Finally, natural convection is concluded to be an intrinsic property of the electron beam when focused into dense air, and can be achieved by carefully adjusting equipment operations parameters.
Comment on “Third order susceptibilities in supercooled liquids and the ‘box model’ theory versus experiments” [J. Chem. Phys. 140, 054508 (2014)]
Authors: Samanta Subarna , Richert Ranko
Published: June 2014

Nonlinear dielectric relaxation experiments are gaining attention because they provide more microscopic insight into structure and dynamics of liquids compared with linear response results. In a recent paper [R. M. Pick, J. Chem. Phys. 140, 054508 (2014)], Pick investigated the “box model” regarding its prediction of time-resolved changes in configurational temperatures that originate from the energy transferred irreversibly from the external field to the sample, analogous to microwave heating. Studying dielectric polarization by a Fourier analysis window that is shifted continuously along the time axis, (opposed to discrete increments of one period), Pick observes oscillations at twice the fundamental frequency and concludes that extra information about these nonlinear dielectric effects are obtained if such oscillations were experimentally detectable. We have observed this oscillatory behavior by nonlinear dielectric experiments, but also demonstrate that this second harmonic component is an immediate consequence of analyzing a quasi-periodic signal subject to a monotonic drift in the amplitude and/or phase.
A hybrid nanoantenna for highly enhanced directional spontaneous emission
Authors: Chou R. Yuanying , Lu Guowei , Shen Hongming , He Yingbo , Cheng Yuqing , Perriat Pascal , Martini Matteo , Tillement Olivier , Gong Qihuang
Published: June 2014

Spontaneous emission modulated by a hybrid plasmonic nanoantenna has been investigated by employing finite-difference time-domain method. The hybrid nanoantenna configurations constituted by a gap hot-spot and of a plasmonic corrugated grating and a metal reflector sandwiching a SiO2 thin layer which appears promising for high spontaneous emission enhancement devices. Simulation assays show that the coupling between the gap-antenna and plasmonic corrugations reaches an ultra-high near-field enhancement factor in the excitation process. Moreover, concerning the emission process, the corrugations concentrate the far-field radiated power within a tiny angular volume, offering unprecedented collection efficiency. In the past decades, many kinds of optical antennas have been proposed and optimized to enhance single molecule detection. However, the excitation enhancement effect for single individual or dimmer plasmonic nanostructure is limited due to intrinsic nonradiative decay of the nanoparticle plasmon and quantum tunneling effect. The proposed hybrid configuration overwhelms the enhancement limit of single individual plasmonic structure. The findings provide an insight into spontaneous emission high enhancement through integrating the functions of different metallic nanostructures.
Catastrophic nanosecond laser induced damage in the bulk of potassium titanyl phosphate crystals
Authors: Wagner Frank R. , Duchateau Guillaume , Natoli Jean-Yves , Akhouayri Hassan , Commandré Mireille
Published: June 2014

Due to its high effective nonlinearity and the possibility to produce periodically poled crystals, potassium titanyl phosphate (KTiOPO4, KTP) is still one of the economically important nonlinear optical materials. In this overview article, we present a large study on catastrophic nanosecond laser induced damage in this material and the very similar RbTiOPO4 (RTP). Several different systematic studies are included: multiple pulse laser damage, multi-wavelength laser damage in KTP, damage resistance anisotropy, and variations of the laser damage thresholds for RTP crystals of different qualities. All measurements were carried out in comparable experimental conditions using a 1064 nm Q-switched laser and some were repeated at 532 nm. After summarizing the experimental results, we detail the proposed model for laser damage in this material and discuss the experimental results in this context. According to the model, nanosecond laser damage is caused by light-induced generation of transient laser-damage precursors which subsequently provide free electrons that are heated by the same nanosecond pulse. We also present a stimulated Raman scattering measurement and confront slightly different models to the experimental data. Finally, the physical nature of the transient damage precursors is discussed and similarities and differences to laser damage in other crystals are pointed out.
Modelling the reaction behavior in reactive multilayer systems on substrates used for wafer bonding
Authors: Masser Robin , Braeuer Joerg , Gessner Thomas
Published: June 2014

Exothermic self-propagating high-temperature synthesis of intermetallic compounds attain increasing interest in the field of wafer bonding in microelectronics and microsystems technology due to local heat generation. Numerical models of self-sustaining reactions in thin multilayer films can be used to predict velocity and shape of the reaction front. This work deals with heat losses to various substrate materials and material compounds used for wafer bonding as well as the prediction of minimal numbers of bilayers required for a self-propagating reaction front. We introduced a cylindrically symmetric finite element approach. In addition to that, the effect of temperature-dependent specific heat capacities was investigated. Numerical computations were performed for Pd/Al multilayers and are compared to experimental data. It was found that the developed formalism is suitable to determine the mutual influence of heat losses and reaction properties. Furthermore, it was demonstrated that minimal numbers of bilayers can be determined more precisely by including temperature-dependent specific heat capacities.
Design of a retarding potential grid system for a neutral particle analyzer
Authors: Titus J. B. , Anderson J. K. , Reusch J. A. , Mezonlin E. D.
Published: June 2014

The ion energy distribution in a magnetically confined plasma can be inferred from charge exchange neutral particles. On the Madison Symmetric Torus (MST), deuterium neutrals are measured by the Florida A&M University compact neutral particle analyzer (CNPA) and the advanced neutral particle analyzer (ANPA). The CNPA energy range covers the bulk deuterium ions to the beginning of the fast ion tail (0.34–5.2 keV) with high-energy resolution (25 channels) while the ANPA covers the vast majority of the fast ion tail distribution (∼10–45 keV) with low energy resolution (10 channels). Though the ANPA has provided insight into fast ion energization in MST plasma, more can be gained by increasing the energy resolution in that energy range. To utilize the energy resolution of the CNPA, fast ions can be retarded by an electric potential well, enabling their detection by the diagnostic. The ion energy distribution can be measured with arbitrary resolution by combining data from many similar MST discharges with different energy ranges on the CNPA, providing further insight into ion energization and fast ion dynamics on MST.
First results of electron temperature measurements by the use of multi-pass Thomson scattering system in GAMMA 10
Authors: Yoshikawa M. , Yasuhara R. , Nagasu K. , Shimamura Y. , Shima Y. , Kohagura J. , Sakamoto M. , Nakashima Y. , Imai T. , Ichimura M. , Yamada I. , Funaba H. , Kawahata K. , Minami T.
Published: June 2014

A multi-pass Thomson scattering (TS) has the advantage of enhancing scattered signals. We constructed a multi-pass TS system for a polarisation-based system and an image relaying system modelled on the GAMMA 10 TS system. We undertook Raman scattering experiments both for the multi-pass setting and for checking the optical components. Moreover, we applied the system to the electron temperature measurements in the GAMMA 10 plasma for the first time. The integrated scattering signal was magnified by approximately three times by using the multi-pass TS system with four passes. The electron temperature measurement accuracy is improved by using this multi-pass system.
Investigation of stopping power for deuterons in partially ionized warm Al plasmas
Authors: He Bin , Wang Jian-Guo
Published: June 2014

The stopping powers for deuterons in Al plasmas with a fixed density of 0.02 g/cm3 and the temperatures at 4.5, 13, and 17 eV are studied in detail for a wide projectile energy range with different models. Comparison of these models indicates that our model is totally in best agreement with the experimental data and the main reason for this is that our calculation for the inelastic processes should be the most reliable. It is found that the difference between our model and the local density approximation model (Wang et al., Phys. Plasmas 5, 2977 (1998)) is mainly due to the quite different physical picture behind them. In Mehlhorn's model (J. Appl. Phys. 52, 6522 (1981)), the Bethe equation is found to overestimate the inelastic stopping in Al plasmas, meanwhile, it is gradually close to our results with temperature decreasing. The model by classical dielectric function with the choice of the maximum of the momentum transfer associated with the temperature is found not suitable to describe the stopping in warm plasmas. With temperature increasing the stopping due to plasma wave rises up which rapidly exceeds the inelastic stopping in warm Al plasmas.
Major contributor to the large piezoelectric response in (1 − x)Ba(Zr0.2Ti0.8)O3 − x(Ba0.7Ca0.3)TiO3 ceramics: Domain wall motion
Authors: Gao Jinghui , Hu Xinghao , Zhang Le , Li Fei , Zhang Lixue , Wang Yu , Hao Yanshuang , Zhong Lisheng , Ren Xiaobing
Published: June 2014

The piezoelectric activity of lead-free Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 (BZT-xBCT) ceramics has been investigated as a function of composition by using Rayleigh analysis under subswitching-electric-field in combination with large-electric-field strain measurement. The result shows that the intrinsic piezoelectric response exhibits peak values in the vicinity of composition-induced R (rhombohedral)-MPB (morphotropic phase boundary) and MPB-T (tetragonal) phase transitions, but being much less than total d33 value. On the other hand, the extrinsic piezoelectric response, especially the one associated with reversible domain wall motion, has been greatly enhanced in the phase instability regime. Our results indicate that the extrinsic piezoelectric activity is the major contributor to the high piezoelectricity in BZT-xBCT ceramics.
Transport properties of Bi-doped FeSe superconductor up to 700 K
Authors: Liu Chia-Jyi , Bhaskar Ankam , Huang Hsueh-Jung , Lin Fei-Hung
Published: June 2014

Polycrystalline samples of Fe1-xBixSe with x = 0.00, 0.02, 0.05, and 0.08 are prepared by conventional solid state reaction. The resistivity and thermopower are measured up to 700 K. The onset superconducting transition temperature decreases slightly with increasing Bi content. Transport behavior of electrical resistivity in the normal state is quite complex. A linear temperature dependence is found between 20 and 100 K. Above 150 K, the electrical resistivity behavior resembles misfit-layered cobalt oxides Ca3Co4O9+δ; a Fermi-liquid behavior of T2 dependence is observed between 150 and 210 K with the Fermi-liquid transport coefficient A having the size between 4.3 × 10−6 and 10 × 10−6 mΩ-cm/K2, followed by an incoherent metal and a high-temperature nonmetal-like behavior. Thermopower behavior is nonconventional. Sign crossover of thermopower occurs both below and above room temperature. According to the dynamical mean field calculations, the negative dip feature of thermopower between 110 and 130 K seems to be associated with excitations of a pseudogap ground state.
Optimization of loading pressure waveforms for piston driven isentropic compression
Authors: Jin Yunsheng , Sun Chengwei , Zhao Jianheng , Wang Guiji , Tan Fuli
Published: June 2014

Smooth ramp loading with higher pressure amplitude is usually preferred in the isentropic compression experiment (ICE) of condensed materials. Optimizing the pressure waveforms of ICE is important in avoiding any shock wave propagating during ramp loading and raising the peak pressure as high as possible. Most reports on shaping ICE waveforms mainly focused on magnetohydrodynamic numerical simulations; a few used the hydrodynamic theory of isentropic flow. However, some points can be improved. Based on one-dimensional planar isentropic flow theory and regarding the ICE loading pressure exerted on the sample's surface as a time-dependent piston boundary condition, a condition for the ramp-to-shock transition as a compression wave propagates in the sample materials, has been derived that forms a necessary condition to avoid such transitions and determines ICE loading pressure waveforms with shorter rise time. A comparison of results is presented for samples of the maximum thickness and for optimized current waveforms obtained in magnetically driven ICEs.
In situ variations of carrier decay and proton induced luminescence characteristics in polycrystalline CdS
Authors: Gaubas E. , Brytavskyi I. , Ceponis T. , Jasiunas A. , Kalesinskas V. , Kovalevskij V. , Meskauskaite D. , Pavlov J. , Remeikis V. , Tamulaitis G. , Tekorius A.
Published: June 2014

Evolution of the microwave-probed photoconductivity transients and of the proton induced luminescence has simultaneously been examined in polycrystalline CdS layers evaporated in vacuum during exposure to a 1.6 MeV proton beam. The decrease of the intensity of luminescence peaked at 510 and 709 nm wavelengths and of values of the effective carrier lifetime has been correlated in dependence of proton irradiation fluence. The defect introduction rate has been evaluated by the comparative analysis of the laser and proton beam induced luminescence. The difference of a carrier pair generation mechanism inherent for light and for a proton beam has been revealed.
Current collapse imaging of Schottky gate AlGaN/GaN high electron mobility transistors by electric field-induced optical second-harmonic generation measurement
Authors: Katsuno Takashi , Manaka Takaaki , Ishikawa Tsuyoshi , Ueda Hiroyuki , Uesugi Tsutomu , Iwamoto Mitsumasa
Published: June 2014

Two-dimensional current collapse imaging of a Schottky gate AlGaN/GaN high electron mobility transistor device was achieved by optical electric field-induced second-harmonic generation (EFISHG) measurements. EFISHG measurements can detect the electric field produced by carriers trapped in the on-state of the device, which leads to current collapse. Immediately after (e.g., 1, 100, or 800 μs) the completion of drain-stress voltage (200 V) in the off-state, the second-harmonic (SH) signals appeared within 2 μm from the gate edge on the drain electrode. The SH signal intensity became weak with time, which suggests that the trapped carriers are emitted from the trap sites. The SH signal location supports the well-known virtual gate model for current collapse.
Interface effect in coupled quantum wells
Authors: Hao Ya-Fei
Published: June 2014

This paper intends to theoretically investigate the effect of the interfaces on the Rashba spin splitting of two coupled quantum wells. The results show that the interface related Rashba spin splitting of the two coupled quantum wells is both smaller than that of a step quantum well which has the same structure with the step quantum well in the coupled quantum wells. And the influence of the cubic Dresselhaus spin-orbit interaction of the coupled quantum wells is larger than that of a step quantum well. It demonstrates that the spin relaxation time of the two coupled quantum wells will be shorter than that of a step quantum well. As for the application in the spintronic devices, a step quantum well may be better than the coupled quantum wells, which is mentioned in this paper.
Dissolution of solid copper in liquid tin enhanced by the liquid structural transition
Authors: Qi Xuan , Ding Guo-Hua , Zhou Guang-Wei
Published: June 2014

Physicochemical properties of liquid metals have great impact on many technological processes. Anomalies in liquid structure of metals are affected by temperature at constant pressure. This study investigated the dissolution kinetics of solid Cu in liquid Sn under the influence of structural transition of liquid Sn at temperatures varying from 673 K to 823 K. Structural transition significantly affected the dissolution rate constant of solid Cu. Correspondingly, application of liquid structural transition significantly decreased the activation energy of dissolution and the apparent activation energy of diffusion.
Effect of Alfvén waves on the growth rate of the electron-cyclotron maser emission
Authors: Wu D. J.
Published: June 2014

By using the non-relativistic approximation for the calculation of growth rates, but taking account of the weakly relativistic modification for the electron-cyclotron resonance condition, it is shown that the effect of Alfvén waves (AWs) on the electron-cyclotron maser emission leads to the significant increase of the O-mode growth rate, but has little effect on the X-mode growth rate. We propose that this is because the O-mode wave has the field-aligned polarization sense in the same as the field-aligned oscillatory current, which is created by the field-aligned oscillatory motion of the energetic electrons caused via the presence of AWs. It is this field-aligned oscillatory current that contributes a novel growth rate to the O-mode wave but has little effect on the X-mode wave.
Effect of nickel grid parameters on production of negative hydrogen ions
Authors: Oohara W. , Yokoyama H. , Takeda Toshiaki , Maetani Y. , Takeda Takashi , Kawata K.
Published: June 2014

Negative hydrogen ions are produced by plasma-assisted catalytic ionization using a nickel grid. When positive ions passing through the grid are decelerated by an electric field, the extraction current density of passing positive ions is sharply reduced by neutralization and negative ionization of the ions. This phenomenon is found to depend on the specific surface area of the grid and the current density.
Simulation investigation of a Ku-band radial line oscillator operating at low guiding magnetic field
Authors: Dang Fangchao , Zhang Xiaoping , Zhong Huihuang , Li Yangmei , Qi Zumin
Published: June 2014

A novel radial line oscillator operating at Ku-band with low guiding magnetic field is proposed in this paper. By using an oversized radial structure, the power handling capacity is enhanced significantly. Based on the small-signal theory, the π/2 mode in radial TM01 mode is selected as the working mode. Furthermore, a radial uniform guiding magnetic field, made up of four solenoids, is designed. As indicated in 2.5-dimensional fully electromagnetic particle-in-cell simulation, high power microwaves with a power of 2.2 GW and a frequency of 14.25 GHz are generated with over 40% efficiency when the electron beam voltage is 300 kV, the beam current 18 kA, and the guiding magnetic field is only 0.6 T. There is no angular non-asymmetric mode discovered in three-dimensional simulation.
SERS and MD simulation studies of a kinase inhibitor demonstrate the emergence of a potential drug discovery tool
Authors: Karthigeyan Dhanasekaran , Siddhanta Soumik , Kishore Annavarapu Hari , Perumal Sathya S. R. R. , Ågren Hans , Sudevan Surabhi , Bhat Akshay V. , Balasubramanyam Karanam , Subbegowda Rangappa Kanchugarakoppal , Kundu Tapas K. , Narayana Chandrabhas
Published: June 2014

Significance

Surface-enhanced Raman spectroscopy along with molecular dynamics simulation is shown to be a useful tool for understanding drug binding to therapeutic proteins. Herein, the selective binding of felodipine to human Aurora A kinase is employed as a test system to demonstrate this powerful technique. Preliminary knowledge of the protein structure makes this approach robust for drug discovery.
Arenium ions are not obligatory intermediates in electrophilic aromatic substitution
Authors: Galabov Boris , Koleva Gergana , Simova Svetlana , Hadjieva Boriana , Schaefer Henry F. , Schleyer Paul von Ragué
Published: June 2014

Significance

Electrophilic substitution is universally regarded as the characteristic reaction of aromatic compounds. Arenium ions are widely accepted as obligatory intermediates in the two-stage (S
E
Ar) mechanism typically described in textbooks, monographs, and reviews. We now challenge this mechanistic paradigm. Our combined computational and experimental investigation of the exemplary halogenation of anisole with Cl
2
in CCl
4
finds that addition–elimination pathways compete with the direct substitution process and also account for the
ortho
–
para
orientation preferences easily. Moreover, the S
E
Ar processes do not involve arenium ion pair intermediates
,
but proceed instead via concerted one-stage single transition state routes. We question not only the generality of the accepted S
E
Ar mechanism, but also the involvement of arenium ion intermediates, when counter ions are present.
Ten best resources on conditional cash transfers
Authors: Marshall Caroline , Hill Peter S
Published: June 2014

The world’s economy is in a fragile state. Although cautiously recovering from a global recession, unemployment rates and poverty levels remain high. At the same time, food and fuel crises have resulted in skyrocketing commodity costs, straining household budgets even further than before. In the wake of these financial pressure points, there has been increased focus on social safety net programmes. More recently, Brazil’s ‘Bolsa Familia’ conditional cash transfer (CCT) programme has celebrated its tenth-year anniversary, renewing focus on this particular aspect of social transfer programmes. This essay examines one particular aspect of these social safety net programmes: CCTs. CCT programmes are useful social programmes that have had demonstrable effects on many different populations. However, they are not a ‘magic bullet’ against poverty, and their image has suffered from unreasonable expectations of their impacts. This 10 best list is an ideal starting point from which a potential user can begin to understand CCTs. There remain significant gaps in the literature behind CCTs, with a particular need for much more research on emerging areas such as impacts on gender, long-term school and health outcomes, methods for increasing efficiency and adapting conditionalities within cultural contexts, among others. However, this list can function as a starting point from which the reader can gain an understanding and appreciation for what we believe to be one of the most innovative social programmes for addressing poverty worldwide.
Reconstructing the Chelyabinsk event: pre-impact orbital evolution
Authors: de la Fuente Marcos C. , de la Fuente Marcos R.
Published: June 2014

The Chelyabinsk superbolide was the largest known natural object to enter the Earth's atmosphere since the Tunguska event in 1908 and it has become a template to understand, manage and mitigate future impacts. Although the event has been documented in great detail, the actual pre-impact orbit of the parent body is still controversial. Here, we revisit this topic using an improved Monte Carlo approach that includes the coordinates of the impact point to compute the most probable solution for the pre-impact orbit (a = 1.62 au, e = 0.53, i = 3 $_{.}^{\circ}$97, Ω = 326 $_{.}^{\circ}$45 and ω = 109 $_{.}^{\circ}$71). We also check all the published solutions using a simple yet robust statistical test to show that many of them have problems to cause an impact at the right time. We use the improved orbit and N-body simulations to revisit the dynamical status of a putative Chelyabinsk asteroid family and confirm that it could be linked to resonant asteroids 2007 BD7 and 2011 EO40. In addition, and as the classification of Chelyabinsk meteorites is well established, a search for meteorite falls of the same chondrite group and petrologic type gives some evidence for the existence of an associated LL5 chondrite cluster.
Near-field limits on the role of faint galaxies in cosmic reionization
Authors: Boylan-Kolchin Michael , Bullock James S. , Garrison-Kimmel Shea
Published: June 2014

Reionizing the Universe with galaxies appears to require significant star formation in low-mass haloes at early times, while local dwarf galaxy counts tell us that star formation has been minimal in small haloes around us today. Using simple models and the ELVIS simulation suite, we show that reionization scenarios requiring appreciable star formation in haloes with Mvir ≈ 108 M⊙ at z = 8 are in serious tension with galaxy counts in the Local Group. This tension originates from the seemingly inescapable conclusion that 30–60 haloes with Mvir > 108 M⊙ at z = 8 will survive to be distinct bound satellites of the Milky Way at z = 0. Reionization models requiring star formation in such haloes will produce dozens of bound galaxies in the Milky Way's virial volume today (and 100–200 throughout the Local Group), each with ≳105 M⊙ of old stars (≳13 Gyr). This exceeds the stellar mass function of classical Milky Way satellites today, even without allowing for the (significant) post-reionization star formation observed in these galaxies. One possible implication of these findings is that star formation became sharply inefficient in haloes smaller than ∼109 M⊙ at early times, implying that the high-z luminosity function must break at magnitudes brighter than is often assumed (at MUV ≃ −14). Our results suggest that the James Webb Space Telescope (and possibly even the Hubble Space Telescope with the Frontier Fields) may realistically detect the faintest galaxies that drive reionization. It remains to be seen how these results can be reconciled with the most sophisticated simulations of early galaxy formation at present, which predict substantial star formation in Mvir ∼ 108 M⊙ haloes during the epoch of reionization.
Rhodovulum
mangrovi sp. nov., a phototrophic alphaproteobacterium isolated from a mangrove forest sediment sample
Authors: Nupur P. , Srinivas T. N. R. , Takaichi S. , Anil Kumar P.
Published: June 2014

A novel Gram-staining-negative, purple non-sulfur bacterium, strain AK41T, was isolated from a sediment sample collected from Coringa mangrove forest, Andhra Pradesh, India. A red–brownish-coloured culture was obtained on modified Pfennig medium after enrichment with 2 % NaCl and 0.3 % pyruvate under 2000 lx illumination. Individual cells were ovoid–rod-shaped and non-motile. Bacteriochlorophyll a and carotenoids of the spheroidene series were present as photosynthetic pigments. Strain AK41T was halophilic and grew photoheterotrophically with a number of organic compounds as carbon sources and electron donors. It was unable to grow photoautotrophically. It did not utilize sulfide or thiosulfate as electron donors. The fatty acids were found to be dominated by C16 : 0 and C18 : 1ω7c. Strain AK41T contained phosphatidylglycerol, phosphatidylethanolamine, an unknown aminolipid and four unknown lipids as polar lipids. Q-10 was the predominant respiratory quinone. The DNA G+C content of strain AK41T was 68.9 mol%. 16S rRNA gene sequence analysis indicated that strain AK41T was a member of the genus

Rhodovulum

and was closely related to

Rhodovulum sulfidophilum

, with 96.0 % similarity to the type strain; the 16S rRNA gene sequence similarity to the type strains of other species of the genus

Rhodovulum

was 93.9–95.8 %. Phylogenetic analyses indicated that strain AK41T clustered with the type strains of

Rhodovulum marinum

,

Rdv. kholense

,

Rdv. sulfidophilum

and

Rdv. visakhapatnamense

with sequence similarity of 95.9–96.2 %. Based on data from the current study, strain AK41T is proposed to represent a novel species of the genus

Rhodovulum

, for which the name Rhodovulum mangrovi sp. nov. is proposed. The type strain of Rhodovulum mangrovi is AK41T ( = MTCC 11825T = JCM 19220T).
Rhizobium populi sp. nov., an endophytic bacterium isolated from Populus euphratica
Authors: Rozahon Manziram , Ismayil Nurimangul , Hamood Buayshem , Erkin Raziya , Abdurahman Mehfuzem , Mamtimin Hormathan , Abdukerim Muhtar , Lal Rup , Rahman Erkin
Published: June 2014

An endophytic bacterium, designated K-38T, was isolated from the storage liquid in the stems ofPopulus euphraticatrees at the ancient Ugan River in Xinjiang, PR China. Strain K-38Twas found to be rod-shaped, Gram-stain-negative, aerobic, non-motile and non-spore-forming. Strain K-38Tgrew at temperatures of 25–37 °C (optimum, 28 °C), at pH 6.0–9.0 (optimum, pH 7.5) and in the presence of 0–3 % (w/v) NaCl with 1 % as the optimum concentration for growth. According to phylogenetic analysis based on 16S rRNA gene sequences, strain K-38Twas assigned to the genusRhizobiumwith highest 16S rRNA gene sequence similarity of 97.2 % toRhizobium rosettiformansW3T, followed byRhizobium nepotum39/7T(96.5 %) andRhizobium borboriDN316T(96.2 %). Phylogenetic analysis of strain K-38Tbased on the protein coding genesrecA,atpDandnifHconfirmed (similarities were less than 90 %) it to be a representative of a distinctly delineated species of the genusRhizobium. The DNA G+C content was determined to be 63.5 mol%. DNA–DNA relatedness between K-38TandR. rosettiformansW3Twas 48.4 %, indicating genetic separation of strain K-38Tfrom the latter strain. The major components of the cellular fatty acids in strain K-38Twere revealed to be summed feature 8 (comprising C18 : 1ω7cand/or C18 : 1ω6c; 57.2 %), C16 : 0(13.6 %) and summed feature 2 (comprising C12 : 0aldehyde, C14 : 03-OH/iso-C16 : 1I and/or unknown ECL 10.928; 11.0 %). Polar lipids of strain K-38Tinclude phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, two unidentified aminophospholipids and two unidentified phospholipids. Q-10 was the major quinone in strain K-38T. Based on phenotypic, chemotaxonomic and phylogenetic properties, strain K-38Trepresents a novel species of the genusRhizobium, for which the nameRhizobiumpopulisp. nov. is proposed. The type strain is K-38T( = CCTCC AB 2013068T = NRRL B-59990T = JCM 19159T).
Rhizobium
paranaense sp. nov., an effective N2-fixing symbiont of common bean (Phaseolus vulgaris L.) with broad geographical distribution in Brazil
Authors: Dall’Agnol Rebeca Fuzinatto , Ribeiro Renan Augusto , Delamuta Jakeline Renata Marçon , Ormeño-Orrillo Ernesto , Rogel Marco Antonio , Andrade Diva Souza , Martínez-Romero Esperanza , Hungria Mariangela
Published: June 2014

Nitrogen (N), the nutrient most required for plant growth, is key for good yield of agriculturally important crops. Common bean (Phaseolus vulgaris L.) can benefit from bacteria collectively called rhizobia, which are capable of fixing atmospheric nitrogen (N2) in root nodules and supplying it to the plant. Common bean is amongst the most promiscuous legume hosts; several described species, in addition to putative novel ones have been reported as able to nodulate this legume, although not always effectively in terms of fixing N2. In this study, we present data indicating that Brazilian strains PRF 35T, PRF 54, CPAO 1135 and H 52, currently classified as

Rhizobium tropici

, represent a novel species symbiont of common bean. Morphological, physiological and biochemical properties differentiate these strains from other species of the genus

Rhizobium

, as do BOX-PCR profiles (less than 60 % similarity), multilocus sequence analysis with recA, gyrB and rpoA (less than 96.4 % sequence similarity), DNA–DNA hybridization (less than 50 % DNA–DNA relatedness), and average nucleotide identity of whole genomes (less than 92.8.%). The novel species is effective in nodulating and fixing N2 with P. vulgaris, Leucaena leucocephala and Leucaena esculenta. We propose the name Rhizobium paranaense sp. nov. for this novel taxon, with strain PRF 35T ( = CNPSo 120T = LMG 27577T = IPR-Pv 1249T) as the type strain.
Hepatitis C virus-induced hepatocyte cell death and protection by inhibition of apoptosis
Authors: Lim Eu Jin , El Khobar Korri , Chin Ruth , Earnest-Silveira Linda , Angus Peter W. , Bock C.-Thomas , Nachbur Ueli , Silke John , Torresi Joseph
Published: June 2014

Chronic hepatitis C virus (HCV) infection results in progressive liver fibrosis leading to cirrhosis and liver cancer. The mechanism for this remains unclear but hepatocyte apoptosis is thought to play a major role. Hepatocyte apoptosis in human liver tissue was determined by immunohistochemistry for cytokeratin 18 (M30 CytoDEATH) and cleaved poly(ADP-ribose) polymerase (PARP).In vitrostudies were performed with replication-defective recombinant adenoviruses expressing HCV proteins (rAdHCV) to study the effects of HCV on cell death in Huh7 cells, primary mouse hepatocytes (PMoHs) and primary human hepatocytes (PHHs). Cell viability and apoptosis were studied using crystal violet assays and Western blots probed for cleaved caspase-3 and cleaved PARP, with and without treatment with the pan-caspase inhibitor Q-VD-OPh and necrostatin-1. Liver tissue of HCV-infected patients expressed elevated levels of apoptotic markers compared with HCV-negative patients. rAdHCV infection reduced cell viability compared with uninfected controls and cells infected with control virus (rAdGFP). Huh7, PMoHs and PHHs infected with rAdHCV showed significantly increased levels of apoptotic markers compared with uninfected controls and rAdGFP-infected cells. In rAdHCV-infected Huh7, treatment with Q-VD-OPh and necrostatin-1 both improved cell viability. Q-VD-Oph also reduced cleaved PARP in rAdHCV-infected Huh7 and PMoHs. Hepatocyte apoptosis is known to be increased in the livers of HCV-infected patients. HCV promoted cell death in primary and immortalized hepatocytes, and this was inhibited by Q-VD-OPh and necrostatin-1. These findings indicate that HCV-induced cell death occurs by both apoptosis and necroptosis, and provide new insights into the mechanisms of HCV-induced liver injury.
The viral envelope is not sufficient to transfer the unique broad cell tropism of Bungowannah virus to a related pestivirus
Authors: Richter Maria , Reimann Ilona , Schirrmeier Horst , Kirkland Peter D. , Beer Martin
Published: June 2014

Bungowannah virus is the most divergent pestivirus, and both origin and reservoir host have not been identified so far. We therefore performedin vitrotropism studies, which showed that Bungowannah virus differs remarkably from other pestiviruses. Interestingly, cell lines of vervet monkey, mouse, human and even of bat origin were susceptible. This broadin vitrotropism was not observed for a chimeric bovine viral diarrhoea virus (BVDV) expressing all structural proteins of Bungowannah virus. The viral envelope was not sufficient to completely transfer the cell tropism of Bungowannah virus to another pestivirus, and viral RNA replication was either markedly reduced or not detectable in a number of different cell lines for the tested BVDV strain and the chimera. We therefore suggest that the replication machinery together with the viral envelope is responsible for the unique broad cell tropism of Bungowannah virus.
Gene-expression patterns in the cerebral cortex of mice infected with porcine haemagglutinating encephalomyelitis virus detected using microarray
Authors: Lan Yungang , Zhao Kui , Zhao Jiakuan , Lv Xiaoling , Wang Gaili , Lu Huijun , Tang Bo , Li Zi , Chang Lingzhu , Jin Zhao , He Wenqi , Gao Feng
Published: June 2014

Porcine haemagglutinating encephalomyelitis virus (PHEV) is the main causative agent of porcine coronavirus-associated disease, which is characterized by encephalomyelitis and involves the central nervous system. Little is known about the molecular mechanisms of brain injury caused by PHEV. To gain insight into the interaction between the virus and host cells, changes in global gene expression in the cerebral cortex of PHEV- or mock-infected mice were investigated using DNA microarray analysis and quantitative real-time PCR. The results of the microarray analysis showed that 365 genes on day 3 post-infection (p.i.) and 781 genes on day 5 p.i. were differentially expressed in response to PHEV infection in the cerebral cortex. The upregulated genes were mainly involved in immune system processes, antigen processing and presentation, the Jak–STAT signalling pathway, the RIG-I-like receptor signalling pathway, Toll-like receptor signalling and apoptosis-related proteases. Significantly downregulated genes were mainly involved in nervous-system development, synaptic transmission, neuron-projection development, the transmission of nerve impulses and negative regulation of glial cell differentiation. The differential expression of these genes suggests a strong antiviral host response, but may also contribute to the pathogenesis of PHEV resulting in encephalomyelitis.
Detecting pairwise correlations in spike trains: an objective comparison of methods and application to the study of retinal waves
Authors: Cutts Catherine S , Eglen Stephen J
Published: June 2014

Correlations in neuronal spike times are thought to be key to processing in many neural systems. Many measures have been proposed to summarise these correlations and of these the correlation index is widely used and is the standard in studies of spontaneous retinal activity. We show that this measure has two undesirable properties: it is unbounded above and confounded by firing rate. We list properties needed for a measure to fairly quantify and compare correlations and we propose a novel measure of correlation — the Spike Time Tiling Coefficient. This coefficient, the correlation index and 33 other measures of correlation of spike times are blindly tested for the required properties on synthetic and experimental data. On the basis of this, we propose a measure (the Spike Time Tiling Coefficient) to replace the correlation index. To demonstrate the benefits of this measure, we re-analyse data from seven key studies which previously used the correlation index to investigate the nature of spontaneous activity. We re-analyse data fromβ2(KO) andβ2(TG) mutants, mutants lacking connexin isoforms and also the age-dependent changes in wild type andβ2(KO) correlations. Re-analysis of the data using the proposed measure can significantly change the conclusions. It leads to better quantification of correlations and therefore better inference from the data. We hope that the proposed measure will have wide applications, and will help clarify the role of activity in retinotopic map formation.
Genetic dissection of courtship song variation using the Drosophila Synthetic Population Resource
Authors: Pischedda Alison , Cochrane Veronica A. , Cochrane Wesley G. , Turner Thomas
Published: June 2014

Connecting genetic variation to trait variation is a grand challenge in biology. Natural populations contain a vast reservoir of fascinating and potentially useful variation, but it is unclear if the causal alleles will generally have large enough effects for us to detect. Without knowing the effect sizes or allele frequency of typical variants, it is also unclear what methods will be most successful. Here, we use a multi-parent advanced intercross population (the Drosophila Synthetic Population Resource) to map natural variation inDrosophilacourtship song traits. Most additive genetic variation in this population can be explained by a modest number of highly resolved QTL. Mapped QTL are universally multiallelic, suggesting that individual genes are “hotspots” of natural variation due to a small target size for major mutations and/or filtering of variation by positive or negative selection. Using quantitative complementation in randomized genetic backgrounds, we provide evidence that one causal allele is harbored in the geneFhos, making this one of the few genes associated with behavioral variation in any taxon.
Formalization of Genome Interval Relations
Authors: Mungall Chris J.
Published: June 2014

In order to take full advantage of next generation genomics data, I need informatics methods to be based on agreed uponformally specifiedstandards that can be implemented easily in a uniform fashion without ambiguity. These standards should be encoded as logical formulae, so that provably correct and efficient decision procedures can be used for query answering and validation.

In this paper I present the core of such a standard for sequence data: a collection of definitions of relations that hold between genomic intervals, and an alegbra for performing operations upon these intervals. I show how these relations can be used to extend formalize concepts in the Sequence Ontology (SO).