bluuebunny/crossref_metadata_2025 huggingface dataset:
Trade-offs between driving nodes and time-to-control in complex networks
Authors: Pequito Sérgio , Preciado Victor M. , Barabási Albert-László , Pappas George J.
Published: January 2017

Recent advances in control theory provide us with efficient tools to determine the minimum number of driving (or driven) nodes to steer a complex network towards a desired state. Furthermore, we often need to do it within a given time window, so it is of practical importance to understand the trade-offs between the minimum number of driving/driven nodes and the minimum time required to reach a desired state. Therefore, we introduce the notion of actuation spectrum to capture such trade-offs, which we used to find that in many complex networks only a small fraction of driving (or driven) nodes is required to steer the network to a desired state within a relatively small time window. Furthermore, our empirical studies reveal that, even though synthetic network models are designed to present structural properties similar to those observed in real networks, their actuation spectra can be dramatically different. Thus, it supports the need to develop new synthetic network models able to replicate controllability properties of real-world networks.
Antarctic ice sheet discharge driven by atmosphere-ocean feedbacks at the Last Glacial Termination
Authors: Fogwill C. J. , Turney C. S. M. , Golledge N. R. , Etheridge D. M. , Rubino M. , Thornton D. P. , Baker A. , Woodward J. , Winter K. , van Ommen T. D. , Moy A. D. , Curran M. A. J. , Davies S. M. , Weber M. E. , Bird M. I. , Munksgaard N. C. , Menviel L. , Rootes C. M. , Ellis B. , Millman H. , Vohra J. , Rivera A. , Cooper A.
Published: January 2017

Reconstructing the dynamic response of the Antarctic ice sheets to warming during the Last Glacial Termination (LGT; 18,000–11,650 yrs ago) allows us to disentangle ice-climate feedbacks that are key to improving future projections. Whilst the sequence of events during this period is reasonably well-known, relatively poor chronological control has precluded precise alignment of ice, atmospheric and marine records, making it difficult to assess relationships between Antarctic ice-sheet (AIS) dynamics, climate change and sea level. Here we present results from a highly-resolved ‘horizontal ice core’ from the Weddell Sea Embayment, which records millennial-scale AIS dynamics across this extensive region. Counterintuitively, we find AIS mass-loss across the full duration of the Antarctic Cold Reversal (ACR; 14,600–12,700 yrs ago), with stabilisation during the subsequent millennia of atmospheric warming. Earth-system and ice-sheet modelling suggests these contrasting trends were likely Antarctic-wide, sustained by feedbacks amplified by the delivery of Circumpolar Deep Water onto the continental shelf. Given the anti-phase relationship between inter-hemispheric climate trends across the LGT our findings demonstrate that Southern Ocean-AIS feedbacks were controlled by global atmospheric teleconnections. With increasing stratification of the Southern Ocean and intensification of mid-latitude westerly winds today, such teleconnections could amplify AIS mass loss and accelerate global sea-level rise.
Photoluminescence quantum efficiency of Er optical centers in GaN epilayers
Authors: Ho V. X. , Dao T. V. , Jiang H. X. , Lin J. Y. , Zavada J. M. , McGill S. A. , Vinh N. Q.
Published: January 2017

We report the quantum efficiency of photoluminescence processes of Er optical centers as well as the thermal quenching mechanism in GaN epilayers prepared by metal-organic chemical vapor deposition. High resolution infrared spectroscopy and temperature dependence measurements of photoluminescence intensity from Er ions in GaN under resonant excitation excitations were performed. Data provide a picture of the thermal quenching processes and activation energy levels. By comparing the photoluminescence from Er ions in the epilayer with a reference sample of Er-doped SiO2, we find that the fraction of Er ions that emits photon at 1.54 μm upon a resonant optical excitation is approximately 68%. This result presents a significant step in the realization of GaN:Er epilayers as an optical gain medium at 1.54 μm.
Quasi-one-dimensional density of states in a single quantum ring
Authors: Kim Heedae , Lee Woojin , Park Seongho , Kyhm Kwangseuk , Je Koochul , Taylor Robert A. , Nogues Gilles , Dang Le Si , Song Jin Dong
Published: January 2017

Generally confinement size is considered to determine the dimensionality of nanostructures. While the exciton Bohr radius is used as a criterion to define either weak or strong confinement in optical experiments, the binding energy of confined excitons is difficult to measure experimentally. One alternative is to use the temperature dependence of the radiative recombination time, which has been employed previously in quantum wells and quantum wires. A one-dimensional loop structure is often assumed to model quantum rings, but this approximation ceases to be valid when the rim width becomes comparable to the ring radius. We have evaluated the density of states in a single quantum ring by measuring the temperature dependence of the radiative recombination of excitons, where the photoluminescence decay time as a function of temperature was calibrated by using the low temperature integrated intensity and linewidth. We conclude that the quasi-continuous finely-spaced levels arising from the rotation energy give rise to a quasi-one-dimensional density of states, as long as the confined exciton is allowed to rotate around the opening of the anisotropic ring structure, which has a finite rim width.
Simultaneous high-speed imaging and optogenetic inhibition in the intact mouse brain
Authors: Bovetti Serena , Moretti Claudio , Zucca Stefano , Dal Maschio Marco , Bonifazi Paolo , Fellin Tommaso
Published: January 2017

Genetically encoded calcium indicators and optogenetic actuators can report and manipulate the activity of specific neuronal populations. However, applying imaging and optogenetics simultaneously has been difficult to establish in the mammalian brain, even though combining the techniques would provide a powerful approach to reveal the functional organization of neural circuits. Here, we developed a technique based on patterned two-photon illumination to allow fast scanless imaging of GCaMP6 signals in the intact mouse brain at the same time as single-photon optogenetic inhibition with Archaerhodopsin. Using combined imaging and electrophysiological recording, we demonstrate that single and short bursts of action potentials in pyramidal neurons can be detected in the scanless modality at acquisition frequencies up to 1 kHz. Moreover, we demonstrate that our system strongly reduces the artifacts in the fluorescence detection that are induced by single-photon optogenetic illumination. Finally, we validated our technique investigating the role of parvalbumin-positive (PV) interneurons in the control of spontaneous cortical dynamics. Monitoring the activity of cellular populations on a precise spatiotemporal scale while manipulating neuronal activity with optogenetics provides a powerful tool to causally elucidate the cellular mechanisms underlying circuit function in the intact mammalian brain.
An analysis of disease-gene relationship from Medline abstracts by DigSee
Authors: Kim Jeongkyun , Kim Jung-jae , Lee Hyunju
Published: January 2017

Diseases are developed by abnormal behavior of genes in biological events such as gene regulation, mutation, phosphorylation, and epigenetics and post-translational modification. Many studies of text mining attempted to identify the relationship between gene and disease by mining the literature, but they did not consider the biological events in which genes show abnormal behaviour in response to diseases. In this study, we propose to identify disease-related genes that are involved in the development of disease through biological events from Medline abstracts. We identified associations between 13,054 genes and 4,494 disease types, which cover more disease-related genes than manually curated databases for all disease types (e.g., Online Mendelian Inheritance in Man) and also than those for specific diseases (e.g., Alzheimer’s disease and hypertension). We show that the text mining findings are reliable, as per the PubMed scale, in that the disease-disease relationships inferred from the literature-wide findings are similar to those inferred from manually curated databases in a well-known study. In addition, literature-wide distribution of biological events across disease types reveals different characteristics of disease types.
A DNA-directed covalent conjugation fluorescence probe for in vitro detection of functional matrix metalloproteinases
Authors: Li Nan , Yi Linglu , He Ziyi , Zhang Weifei , Li Haifang , Lin Jin-Ming
Published: January 2017

Matrix metalloproteinases (MMPs) have been considered to contribute to the progression of tumorigenesis and invasion; MMP-9 in particular, has been regarded as a priority target in cancer treatment due to its up-regulation in malignant tissues.
Development of a single-step immunoassay microdevice based on a graphene oxide-containing hydrogel possessing fluorescence quenching and size separation functions
Authors: Shirai Akihiro , Nakashima Kaho , Sueyoshi Kenji , Endo Tatsuro , Hisamoto Hideaki
Published: January 2017

An immunoassay was successfully integrated into a “single-step” by developing a microdevice composed of a GO-containing hydrogel and a PDMS microchannel array with a PEG coating containing a fluorescently-labelled antibody.
On the formation of concentric 2D multicomponent assemblies at the solution–solid interface
Authors: Velpula Gangamallaiah , Takeda Takashi , Adisoejoso Jinne , Inukai Koji , Tahara Kazukuni , Mali Kunal S. , Tobe Yoshito , De Feyter Steven
Published: January 2017

We report on the design and fabrication of a four-component supramolecular network consisting of three concentric shells around a central guest.
Synthesis of chiral sultams via palladium-catalyzed intramolecular asymmetric reductive amination
Authors: Song Bo , Yu Chang-Bin , Ji Yue , Chen Mu-Wang , Zhou Yong-Gui
Published: January 2017

A palladium-catalyzed intramolecular reductive amination of ketones with weakly nucleophilic sulfonamides has been developed, providing facile access to a range of chiral sultams with up to 99% enantioselectivity.
Interfacial water on organic substrates at cryogenic temperatures: hydrogen bonding and quantification in the submonolayer regime
Authors: Houdoux D. , Houplin J. , Amiaud L. , Lafosse A. , Dablemont C.
Published: January 2017

H2O adsorption at 28 K on a model hydrophilic organized layer was investigated at the molecular level by vibrational spectroscopy.
Microsolvation of the pyrrole cation (Py+) with nonpolar and polar ligands: infrared spectra of Py+–Ln with L = Ar, N2, and H2O (n ≤ 3)
Authors: Schütz Markus , Matsumoto Yoshiteru , Bouchet Aude , Öztürk Murat , Dopfer Otto
Published: January 2017

IR spectra and dispersion-corrected density functional calculations of pyrrole cluster ions with Ar, N2, and H2O reveal the competition between H-bonding and π-stacking motifs of this prototypical heterocyclic aromatic cation in a hydrophobic and hydrophilic solvent.
Coexistence phenomenon of Ce3+–Ce4+and Eu2+–Eu3+in Ce/Eu co-doped LiBaB9O15phosphor: luminescence and energy transfer
Authors: Li Ting , Li Panlai , Wang Zhijun , Xu Shuchao , Bai Qiongyu , Yang Zhiping
Published: January 2017

Ce/Eu-doped LiBaB9O15(LBB) samples were preparedviaconventional high temperature solid state reactions.
Hot electron-driven photocatalytic water splitting
Authors: Hou Bingya , Shen Lang , Shi Haotian , Kapadia Rehan , Cronin Stephen B.
Published: January 2017

We report measurements of photocatalytic water splitting using Au films with and without TiO2 coatings.
Soft matter interactions at the molecular scale: interaction forces and energies between single hydrophobic model peptides
Authors: Stock Philipp , Utzig Thomas , Valtiner Markus
Published: January 2017

The interaction between single hydrophobic molecules is quantitatively characterized by using an atomic force microscope (AFM).
Molecular interactions of organic molecules at the air/water interface investigated by sum frequency generation vibrational spectroscopy
Authors: Wang Wenting , Ye Shuji
Published: January 2017

Second-order Fermi resonanance interaction provides an effective vibrational optical ruler for characterizing the molecular interactions at interfaces.
Deep eutectic solvents: similia similibus solvuntur?
Authors: Zahn Stefan
Published: January 2017

Multiple similar interactions in reline facilitates a large entropy and low melting point of the liquid state.
Crystalline structure and thermotropic behavior of alkyltrimethylphosphonium amphiphiles
Authors: Gamarra Ana , Urpí Lourdes , Martínez de Ilarduya Antxon , Muñoz-Guerra Sebastián
Published: January 2017

Alkyltrimethylphosphonium bromides are highly thermally stable compounds that are able to adopt crystalline and mesomorphic phases as a function of temperature.
Multi-shelled ceria hollow spheres with a tunable shell number and thickness and their superior catalytic activity
Authors: Liao Yuanyuan , Li Yuan , Wang Lei , Zhao Yongxia , Ma Danyang , Wang Biqing , Wan Yongxia , Zhong Shengliang
Published: January 2017

Multi-shelled ceria hollow spheres with tunable shell number and thickness have been prepared via a coordination polymer precursor method. Besides, this method was extended to the preparation of other rare earth oxides. Au and AuPd loaded ceria hollow spheres composites display superior catalytic activity.
Azido- and amido-substituted gallium hydrides supported by N-heterocyclic carbenes
Authors: Swarnakar Anindya K. , Ferguson Michael J. , McDonald Robert , Rivard Eric
Published: January 2017

The synthesis of azido- and amido-gallanes supported by hindered N-heterocyclic carbene donors is reported.
Isobutane/butene alkylation catalyzed by ionic liquids: a more sustainable process for clean oil production
Authors: Wang Hui , Meng Xiangzhan , Zhao Guoying , Zhang Suojiang
Published: January 2017

This article provides a comprehensive review on the catalysis of isobutane/butene alkylation by ionic liquids for clean oil production.
Organocatalytic oxidation of substituted anilines to azoxybenzenes and nitro compounds: mechanistic studies excluding the involvement of a dioxirane intermediate
Authors: Voutyritsa Errika , Theodorou Alexis , Kokotou Maroula G. , Kokotos Christoforos G.
Published: January 2017

Organocatalytic and environmentally friendly approaches for the selective oxidation of substituted anilines either to azoxybenzenes or to nitro compounds were developed.
3D-reconstruction of chemical state distributions in stratified samples by spatially resolved micro-X-ray resonant Raman spectroscopy
Authors: Leani J. J. , Pérez R. D. , Robledo J. I. , Sánchez H. J.
Published: January 2017

X-ray resonant Raman scattering was used, for the first time, in a confocal setup with the aim of determining different compounds of the same element in a copper-multilayer sample.
Soft and rigid core latex nanoparticles prepared by RAFT-mediated surfactant-free emulsion polymerization for cellulose modification – a comparative study
Authors: Engström J. , Hatton F. L. , Wågberg L. , D'Agosto F. , Lansalot M. , Malmström E. , Carlmark A.
Published: January 2017

Latex nanoparticles of high and low Tg-core block-copolymers were produced and their adsorption to (nano)cellulose surfaces was investigated.
Multilateral characterization of recombinant spider silk in thermal degradation
Authors: Dao Anh T. N. , Nakayama K. , Shimokata J. , Taniike T.
Published: January 2017

Elucidating the complex mechanism of thermo-oxidative degradation of recombinant spider silk by systematic characterization and correlation coefficient approach.
Asymmetric tin–vanadium redox electrolyte for hybrid energy storage with nanoporous carbon electrodes
Authors: Lee Juhan , Tolosa Aura , Krüner Benjamin , Jäckel Nicolas , Fleischmann Simon , Zeiger Marco , Kim Daekyu , Presser Volker
Published: January 2017

Redox active electrolytes in combination with nanoporous carbon electrodes combine high power with high energy storage performance metrics.
Copper-doped mesoporous hydroxyapatite microspheres synthesized by a microwave-hydrothermal method using creatine phosphate as an organic phosphorus source: application in drug delivery and enhanced bone regeneration
Authors: Yu Weilin , Sun Tuan-Wei , Ding Zhenyu , Qi Chao , Zhao Huakun , Chen Feng , Shi Zhongmin , Zhu Ying-Jie , Chen Daoyun , He Yaohua
Published: January 2017

The Cu-MHMs show great potential in drug delivery and bone augmentation.
Organic light emitting diodes with horizontally oriented thermally activated delayed fluorescence emitters
Authors: Kim D. H. , Inada K. , Zhao L. , Komino T. , Matsumoto N. , Ribierre J. C. , Adachi C.
Published: January 2017

Horizontal orientation of the emission transition dipole of TADF molecules plays a critical role on the light outcoupling efficiency and the performance of TADF organic light-emitting diodes.
Oxidation-enhanced emission: exploring novel AIEgens from thieno[3,2-b]thiophene S,S-dioxide
Authors: Bin Chen Bin Chen , Zhang Han , Luo Wenwen , Nie Han , Hu Rongrong , Qin Anjun , Zhao Zujin , Tang Ben Zhong
Published: January 2017

A novel aggregation-induced emission (AIE) system with high solid-state emission efficiency is established by oxidizing thieno[3,2-b]thiophene to thieno[3,2-b]thiophene S,S-dioxide.
Anisotropy induced anomalies in Dy1−xTbxAl2
Authors: Khan M. , Pathak A. K. , Mudryk Y. , Gschneidner, Jr. K. A. , Pecharsky V. K.
Published: January 2017

The Dy1−xTbxAl2 alloys have been investigated by X-ray powder diffraction, heat capacity, and magnetic measurements.
Compact balanced bandpass filter using isosceles right triangular patch resonator
Authors: Liu Qianwen , Wang Jianpeng , He Yixuan
Published: January 2017

A compact balanced bandpass filter (BPF) by using the isosceles right triangular patch resonator is presented. Stemming from the mode degeneration properties of the square patch resonator with single excitation located at its corner, the specific current distribution on this square patch resonator is investigated. Based on that, a new type of half‐mode square patch resonator named as the isosceles right triangular patch resonator is derived and proposed. Afterwards, resonant properties of the new patch resonator under different excitation forms are also investigated. Subsequently, balanced BPF has been implemented by adopting appropriate coupling structure among four isosceles right triangular patch resonators. Finally, to verify the design concept, a second‐order Chebyshev balanced BPF centred at 2.44 GHz with 3 dB fractional bandwidth of 6.15% is designed and fabricated. Good agreement can be observed between the simulated and the measured results.
Joint weight and metric learning for person re‐identification based on efficient positive semi‐definite constraints and colour ranking aggregation
Authors: Gao Bin , Zeng Mingyong , Sun Fenggang , Liu Jie
Published: January 2017

For person re‐identification, traditional accelerated gradient algorithm‐based metric‐learning approaches suffer from the fixed weight and degrade the match performance. To this end, a novel and efficient method is proposed to learn the weight and metric jointly. Moreover, an optimised proximal gradient algorithm approach is adopted to further speed up the convergence rate. Simulation results verify the superior performance of the proposed method.
Low power‐delay‐product dynamic CMOS circuit design techniques
Authors: Xue H. , Ren S.
Published: January 2017

Two low power‐delay‐product (PDP) dynamic CMOS circuit design techniques are proposed. The techniques can simply modify existing dynamic CMOS designs to improve dynamic circuit delay and PDP. Conventional benchmark circuits and the modified circuits using the proposed techniques are implemented in 90 nm CMOS technology with a 1.2 V power supply. Simulation results indicate that the proposed techniques can improve circuit PDP by 19.2 and 61.9% in two non‐inverted dynamic benchmarks, respectively, and 6.2 and 33.72% in two inverted dynamic benchmarks, respectively.
Development of the dense plasma focus for short-pulse applications
Authors: Bennett N. , Blasco M. , Breeding K. , Constantino D. , DeYoung A. , DiPuccio V. , Friedman J. , Gall B. , Gardner S. , Gatling J. , Hagen E. C. , Luttman A. , Meehan B. T. , Misch M. , Molnar S. , Morgan G. , O'Brien R. , Robbins L. , Rundberg R. , Sipe N. , Welch D. R. , Yuan V.
Published: January 2017

The dense plasma focus (DPF) has long been considered a compact source for pulsed neutrons and has traditionally been optimized for the total neutron yield. In this paper, we describe the efforts to optimize the DPF for short-pulse applications by introducing a reentrant cathode at the end of the coaxial plasma gun. The resulting neutron pulse widths are reduced by an average of 21±9% from the traditional long-drift DPF design. Pulse widths and yields achieved from deuterium-tritium fusion at 2 MA are 61.8±30.7 ns FWHM and 1.84±0.49×1012 neutrons per shot. Simulations were conducted concurrently to elucidate the DPF operation and confirm the role of the reentrant cathode. A hybrid fluid-kinetic particle-in-cell modeling capability demonstrates correct sheath velocities, plasma instabilities, and fusion yield rates. Consistent with previous findings that the DPF is dominated by beam-target fusion from superthermal ions, we estimate that the thermonuclear contribution is at the 1% level.
An analytical model of multi-component radio frequency capacitively coupled plasma and experimental validation
Authors: Saikia Partha , Bhuyan Heman , Favre Mario , Wyndham Edmundo , Veloso Felipe
Published: January 2017

An analytical model describing the hydrogen added argon radio frequency capacitively coupled plasma is presented and its predictions are tested with the experimental results. In the analytical model, it is found that the rf current density, electron temperature and density, as well as the density of light ion in multi-component plasma collectively influence the normalized sheath thickness and potential. As for low pressure rf plasma, the sheath potential is the qualitative measure of the DC self bias, the change of DC self bias with hydrogen addition is predicted in this model. The values of electron density and temperature as a function of hydrogen content in the discharge is calculated on the basis of a homogeneous discharge model using the rms values of current and voltage as well as by rf compensated Langmuir probe at different experimental conditions. In the experiment with hydrogen added argon plasma, the rf power as well as the working pressures are varied. The presence of hydrogen in the argon discharge leads to the decrease of electron density and increase of electron temperature. The measured DC self bias for the hydrogen added argon plasma is found lower than the pristine argon plasma. This decrease of DC self bias with hydrogen addition is in accordance with predictions of the theoretical model.
Semiclassical basis sets for the computation of molecular vibrational states
Authors: Revuelta F. , Vergini E. , Benito R. M. , Borondo F.
Published: January 2017

In this paper, we extend a method recently reported [F. Revuelta et al., Phys. Rev. E 87, 042921 (2013)] for the calculation of the eigenstates of classically highly chaotic systems to cases of mixed dynamics, i.e., those presenting regular and irregular motions at the same energy. The efficiency of the method, which is based on the use of a semiclassical basis set of localized wave functions, is demonstrated by applying it to the determination of the vibrational states of a realistic molecular system, namely, the LiCN molecule.
Stripe magnetic domains in CeY2Fe5O12 (Ce:YIG) epitaxial films
Authors: Ghising Pramod , Hossain Z. , Budhani R. C.
Published: January 2017

Thin epitaxial films of CeY2Fe5O12 are deposited on (111) Gd3Ga5O12 substrates using pulsed laser ablation. The films exhibit low coercivity (3 mT), high saturation magnetization (102 mT), and excellent epitaxy. High resolution magnetic force microscopy (MFM) images of the film reveal a prominent stripe magnetic domain pattern due to a non-coplanar magnetization vector M→. Intensity analysis of the MFM images allows extraction of the orientation angle θc of M→ with respect to the plane of the film. We have recorded the changes in the width of the stripes and their disappearance as the strength of an in-plane magnetic field is increased. A simple model based on sinusoidal variation of M→ correctly predicts the change in the width of the stripe domains.
Magnetite nano-islands on silicon-carbide with graphene
Authors: Anderson Nathaniel A. , Zhang Qiang , Hupalo Myron , Rosenberg Richard A. , Tringides Michael C. , Vaknin David
Published: January 2017

X-ray magnetic circular dichroism (XMCD) measurements of iron nano-islands grown on graphene and covered with a Au film for passivation reveal that the oxidation through defects in the Au film spontaneously leads to the formation of magnetite nano-particles (i.e., Fe3O4). The Fe nano-islands (20 and 75 monolayers; MLs) are grown on epitaxial graphene formed by thermally annealing 6H-SiC(0001) and subsequently covered, in the growth chamber, with nominal 20 layers of Au. Our X-ray absorption spectroscopy and XMCD measurements at applied magnetic fields show that the thin film (20 ML) is totally converted to magnetite, whereas the thicker film (75 ML) exhibits properties of magnetite but also those of pure metallic iron. Temperature dependence of the XMCD signal (of both samples) shows a clear transition at TV≈120 K consistent with the Verwey transition of bulk magnetite. These results have implications on the synthesis of magnetite nano-crystals and also on their regular arrangements on functional substrates such as graphene.
P-type surface transfer doping of oxidised silicon terminated (100) diamond
Authors: Sear Michael J. , Schenk Alex K. , Tadich Anton , Stacey Alastair , Pakes Christopher I.
Published: January 2017

High-resolution core-level photoemission was used to examine the interaction between the oxidised silicon-terminated diamond (100) surface and the molecular acceptor MoO3. An observed downward shift in the Fermi level position, accompanied by the appearance of two distinct charge states of MoO3, indicates charge transfer from the surface into the MoO3 adlayer in the form of surface transfer doping with a concurrent accumulation of holes in the diamond.
Electromechanical scale-bridging model for piezoelectric nanostructures
Authors: Lim Jin-Myoung , Cho Kyeongjae , Cho Maenghyo
Published: January 2017

In past experimental studies, piezoelectric nanostructures have exhibited extraordinary behavior and unusual deformations. In order to establish the corresponding theoretical framework, a scale-bridging model, which takes into account surface piezoelectricity and the wave nature of electrons in ultra-narrow media by reflecting lattice distortions of atomic structures, has been proposed in this work. After applying this model to ZnO nanofilms with thicknesses ranging between 0.3 nm and 2.8 nm, asymmetric lattice distortions of the Zn- and O-terminated surfaces were observed and subsequently quantified using a lattice distortion factor. The material characteristics evaluated by using this model were found to be in good agreement with the results of first-principles calculations and corresponding experiments, and thus can be used for predicting the properties of thicker nanofilms. After bridging to the continuum scale, the data produced via finite element analysis significantly differed from the results obtained by the conventional model, owing to the unusual deformations caused by the nano-sized material properties and asymmetric surface characteristics. The obtained results help to achieve a better understanding of the properties of piezoelectric nanostructures with extraordinary characteristics and, therefore, can be used for the nanostructural design.
Tunable electronic properties of two-dimensional nitrides for light harvesting heterostructures
Authors: Prete Maria Stella , Mosca Conte Adriano , Gori Paola , Bechstedt Friedhelm , Pulci Olivia
Published: January 2017

We study the electronic properties of two-dimensional (2D) group-III nitrides BN, AlN, GaN, InN, and TlN by first-principles approaches. With increasing group-III atomic number, a decrease of the electronic gap from 6.7 eV to 0 eV takes place. 2D GaN and 2D InN in honeycomb geometry present a direct gap at Γ, while the honeycomb structures of BN and AlN tend to be indirect semiconductors with the valence band maximum at K. Alloying of the nitrides allows tuning the gap with cation composition. Interestingly, InxGa1−xN and InxTl1−xN alloys enable, with varying x, to construct type I or type II heterostructures. We demonstrate that it is possible to tailor the electronic and optical response from UV to IR. We suggest that 2D InGaN and InTlN heterostructures may efficiently harvest light and serve as building blocks for a future generation of III–V solar cells. Finally, 2D InTlN with a low In content is eligible as the emitter and detector for THz applications.
Polyanhydride Nanoparticles: Thiol–Ene ‘Click’ Polymerizations Provide Functionalized and Cross-Linkable Nanoparticles with Tuneable Degradation Times
Authors: Durham Olivia Z. , Poetz Katie L. , Shipp Devon A.
Published: January 2017

The production of degradable polyanhydride-based nanoparticles that exhibit tuneable degradation times using thiol–ene ‘click’ polymerizations is described. Linear polyanhydrides were used in the production of nanoparticles with diameters typically in the range of 250–400 nm using the emulsion–solvent evaporation method. A variety of reaction parameters, including polymer composition, surfactant species and concentration, sonication amplitude and duration, and reaction medium, were investigated to examine their impact on particle size. Also demonstrated are the potential to incorporate diverse functionality in the polymer network, the ability to load nanoparticles with a payload as exemplified by a model dye compound, and how the introduction of cross-linking into the polymer network extends degradation profiles, thereby allowing for tuneable degradation timeframes, which range from ~1 day to 14 days.
SNX-1 and RME-8 oppose the assembly of HGRS-1/ESCRT-0 degradative microdomains on endosomes
Authors: Norris Anne , Tammineni Prasad , Wang Simon , Gerdes Julianne , Murr Alexandra , Kwan Kelvin Y. , Cai Qian , Grant Barth D.
Published: January 2017

Significance

Endosomes are membrane-bound organelles that are important for nutrient uptake, protein and lipid sorting, and signal transduction. When integral membrane proteins have reached the endosomal system, they can be sent to the lysosome for degradation or recycled for reuse. Here we provide insight into how the machinery important for reuse controls the machinery that mediates degradation. We show that these opposing functions occupy physically distinct regions of the endosomes, termed microdomains, and that this separation is likely to provide a physical framework for a variety of sorting decisions.
Cryo-EM study of slow bee paralysis virus at low pH reveals iflavirus genome release mechanism
Authors: Kalynych Sergei , Füzik Tibor , Přidal Antonín , de Miranda Joachim , Plevka Pavel
Published: January 2017

Significance

Here, we present a structural analysis of the genome delivery of slow bee paralysis virus (SBPV) that can cause lethal infections of honeybees and bumblebees. The possibility of blocking virus genome delivery would provide a tool to prevent the spread of this viral pathogen. We describe the three-dimensional structures of SBPV particles in a low-pH buffer, which imitates the conditions that the virus is likely to encounter after cell entry. The low pH induces a reduction in the contacts between capsid proteins and a formation of pores within the capsid that may serve as channels for the genome release. Our work provides a structural characterization of iflavirus genome release.
Fife organizes synaptic vesicles and calcium channels for high-probability neurotransmitter release
Authors: Bruckner Joseph J. , Zhan Hong , Gratz Scott J. , Rao Monica , Ukken Fiona , Zilberg Gregory , O’Connor-Giles Kate M.
Published: January 2017

The strength of synaptic connections varies significantly and is a key determinant of communication within neural circuits. Mechanistic insight into presynaptic factors that establish and modulate neurotransmitter release properties is crucial to understanding synapse strength, circuit function, and neural plasticity. We previously identified Drosophila Piccolo-RIM-related Fife, which regulates neurotransmission and motor behavior through an unknown mechanism. Here, we demonstrate that Fife localizes and interacts with RIM at the active zone cytomatrix to promote neurotransmitter release. Loss of Fife results in the severe disruption of active zone cytomatrix architecture and molecular organization. Through electron tomographic and electrophysiological studies, we find a decrease in the accumulation of release-ready synaptic vesicles and their release probability caused by impaired coupling to Ca2+ channels. Finally, we find that Fife is essential for the homeostatic modulation of neurotransmission. We propose that Fife organizes active zones to create synaptic vesicle release sites within nanometer distance of Ca2+ channel clusters for reliable and modifiable neurotransmitter release.
Recombinant fowlpox virus vector-based vaccines: expression kinetics, dissemination and safety profile following intranasal delivery
Authors: Townsend David G , Trivedi Shubhanshi , Jackson Ronald J , Ranasinghe Charani
Published: January 2017

We have previously established that mucosal uptake of recombinant fowlpox virus (rFPV) vaccines is far superior to other vector-based vaccines. Specifically, intranasal priming with rFPV vaccines can recruit unique antigen-presenting cells, which induce excellent mucosal and systemic HIV-specific CD8+ T-cell immunity. In this study, we have for the first time investigated the in vivo dissemination, safety and expression kinetics of rFPV post intranasal delivery using recombinant viruses expressing green fluorescent protein or mCherry. Both confocal microscopy of tissue sections using green fluorescent protein and in vivo Imaging System (IVIS) spectrum live animal and whole organ imaging studies using mCherry revealed that (i) the peak antigen expression occurs 12 to 24 h post vaccination and no active viral gene expression is detected 96 h post vaccination. (ii) The virus only infects the initial vaccination site (lung and nasal cavity) and does not disseminate to distal sites such as the spleen or gut. (iii) More importantly, rFPV does not cross the olfactory receptor neuron pathway. Collectively, our findings indicate that rFPV vector-based vaccines have all the hallmarks of a safe and effective mucosal delivery vector, suitable for clinical evaluation.
Cytolethal distending toxin-producing Escherichia coli strains causing severe diarrhoea in young Mexican children
Authors: Meza-Segura Mario , Zaidi Mussaret Bano , Maldonado-Puga Samantha , Huerta-Cantillo Jazmin , Chavez-Dueñas Lucia , Navarro-Garcia Fernando , Estrada-Garcia Teresa
Published: January 2017

Introduction. Cytolethal distending toxins (CDTs), encoded by cdt genes, have DNase activity leading to cellular and nuclear distension, resulting in irreversible cell cycle arrest and apoptosis of target cells. cdt-positive Escherichia coli strains have been isolated from children with diarrhoea. There is, however, scant information on the prevalence and clinical presentation of diarrhoeal disease caused by these strains. Furthermore, toxin production of cdt-positive strains is rarely confirmed. We report five young children with diarrhoea caused by CDT-producing E. coli in whom stools were negative for other bacterial or enteric pathogens.

Case presentation. On admission to hospital, all children presented watery diarrhoea with high stool output (range 7–20 stools/24 h); five had fever of 38 °C or more and four presented vomiting. Dehydration was present in four patients, one of whom had hypovolaemic shock; one child also presented hyponatraemia and hypokalaemia. In two children, cdt-positive strains were classified as typical and atypical enteropathogenic E. coli, and the remaining three harboured cdt-positive strains that did not belong to any diarrhoeagenic pathogroup. One cdt-positive strain from each case was characterized by a CDT cytotoxic assay and a cdt type-specific PCR. All strains produced the characteristic cellular intoxication due to CDT. Two strains carried the cdt-I, one cdt-III, one cdt-IV, and one concurrently had cdt-I, cdt-II and cdt-III genes.

Conclusion. Our results suggest that CDT-producing E. coli strains are an infrequent, albeit significant, cause of severe diarrhoeal illness in children. Future research should measure the true burden of cdt-positive E. coli diarrhoea among children.
Neural precursors of deliberate and arbitrary decisions in the study of voluntary action
Authors: Maoz U. , Yaffe G. , Koch C. , Mudrik L.
Published: January 2017

The readiness potential (RP)—a key ERP correlate of upcoming action—is known to precede subjects’ reports of their decision to move. Some view this as evidence against a causal role for consciousness in human decision-making and thus against free-will. Yet those studies focused on arbitrary decisions—purposeless, unreasoned, and without consequences. It remains unknown to what degree the RP generalizes to deliberate, more ecological decisions. We directly compared deliberate and arbitrary decision-making during a $1000-donation task to non-profit organizations. While we found the expected RPs for arbitrary decisions, they were strikingly absent for deliberate ones. Our results and drift-diffusion model are congruent with the RP representing accumulation of noisy, random fluctuations that drive arbitrary—but not deliberate—decisions. They further point to different neural mechanisms underlying deliberate and arbitrary decisions, challenging the generalizability of studies that argue for no causal role for consciousness in decision-making to real-life decisions.

Significance Statement

The extent of human free will has been debated for millennia. Previous studies demonstrated that neural precursors of action—especially the readiness potential—precede subjects’ reports of deciding to move. Some viewed this as evidence against free-will. However, these experiments focused on arbitrary decisions—e.g., randomly raising the left or right hand. We directly compared deliberate (actual $1000 donations to NPOs) and arbitrary decisions, and found readiness potentials before arbitrary decisions, but—critically—not before deliberate decisions. This supports the interpretation of readiness potentials as byproducts of accumulation of random fluctuations in arbitrary but not deliberate decisions and points to different neural mechanisms underlying deliberate and arbitrary choice. Hence, it challenges the generalizability of previous results from arbitrary to deliberate decisions.
Adaptive Cortical Parcellations for Source Reconstructed EEG/MEG Connectomes
Authors: Farahibozorg Seyedeh-Rezvan , Henson Richard N , Hauk Olaf
Published: January 2017

There is growing interest in the rich temporal and spectral properties of the brain's functional connectome that are provided by Electro- and Magnetoencephalography (EEG/MEG). However, the problem of leakage between brain sources that arises when reconstructing brain activity from EEG/MEG recordings outside the head makes it difficult to distinguish true connections from spurious connections, even when connections are based on measures that ignore zero-lag dependencies. In particular, standard anatomical parcellations for potential cortical sources tend to over- or under-sample the real spatial resolution of EEG/MEG. By using information from cross-talk functions (CTFs) that objectively describe leakage for a given sensor configuration and distributed source reconstruction method, we introduce methods for optimising the number of parcels while simultaneously minimising the leakage between them. More specifically, we compare two image segmentation algorithms: 1) a split-and-merge (SaM) algorithm based on standard anatomical parcellations and 2) a region growing (RG) algorithm based on all the brain vertices with no prior parcellation. Interestingly, when applied to minimum-norm reconstructions for EEG/MEG configurations from real data, both algorithms yielded approximately 70 parcels despite their different starting points, suggesting that this reflects the resolution limit of this particular sensor configuration and reconstruction method. Importantly, when compared against standard anatomical parcellations, resolution matrices of adaptive parcellations showed notably higher sensitivity and distinguishability of parcels. Furthermore, extensive simulations of realistic networks under various circumstances revealed significant improvements in network reconstruction accuracies, particularly in reducing false leakage-induced connections. Adaptive parcellations therefore allow a more accurate reconstruction of functional EEG/MEG connectomes.

Highlights

We introduce adaptive cortical parcellation algorithms for E/MEG source estimation.

Algorithms are based on cross-talk functions and image segmentation methods.

The resulting parcellations yielded ~70 parcels regardless of starting point.

Sensitivity and distinguishability improved compared to anatomical parcellations.

Accuracy of realistic whole-brain network reconstruction improved significantly.
Multiple zebrafishatoh1genes specify a diversity of neuronal types in the zebrafish cerebellum
Authors: Kidwell Chelsea U. , Su Chen-Ying , Hibi Masahiko , Moens Cecilia B.
Published: January 2017

The basic Helix-Loop-Helix transcription factor Atoh1 is required for the specification of multiple neuron types in the mammalian hindbrain including tegmental, precerebellar output neurons and cerebellar granule neurons. How a single proneural gene specifies so many neuron types from a single progenitor zone, the upper rhombic lip (URL), is not known. Here we use the zebrafish to explore the role ofatoh1in cerebellar neurogenesis. Using transgenic reporters we show that zebrafishatoh1c-expressing cells give rise to tegmental and granule cell populations that, together with previously describedatoh1a-derived neuron populations, resemble the diversity ofatoh1derivatives observed in mammals. Using genetic mutants we find that of the three zebrafishatoh1paralogs,atoh1candatoh1aare required for the full complement of granule neurons in the zebrafish cerebellum. Interestingly,atoh1aandatoh1cspecify non-overlapping granule populations, indicating that fish use multipleatoh1genes to generate granule neuron diversity that is not detected in mammals. By live imaging of neurogenesis at the URL we show thatatoh1cis not required for the specification of granule neuron progenitors but promotes their delamination from the URL epithelium and this process is critical for neuronal maturation. This study thus provides a better understanding of how proneural transcription factors regulate neurogenesis in the vertebrate cerebellum.

Summary statement

atoh1genes specify distinct populations of tegmental and granule neurons in the zebrafish hindbrain and promote their delamination from the neuroepithelium, a process critical for neuronal maturation.
A complex multi-locus, multi-allelic genetic architecture underlying the long-term selection-response in the Virginia body weight line of chickens
Authors: Zan Yanjun , Sheng Zheya , Rönnegård Lars , Honaker Christa F. , Siegel Paul B. , Carlborg Örjan
Published: January 2017

The ability of a population to adapt to changes in their living conditions, whether in nature or captivity, often depends on polymorphisms in multiple genes across the genome. In-depth studies of such polygenic adaptations are difficult in natural populations, but can be approached using the resources provided by artificial selection experiments. Here, we dissect the genetic mechanisms involved in long-term selection responses of the Virginia chicken lines, populations that after 40 generations of divergent selection for 56-day body weight display a nine-fold difference in the selected trait. In the F15 generation of an intercross between the divergent lines, 20 loci explained more than 60% of the additive genetic variance for the selected trait. We focused particularly on seven major QTL and found that only two fine-mapped to single, bi-allelic loci; the other five contained linked loci, multiple alleles or were epistatic. This detailed dissection of the polygenic adaptations in the Virginia lines provides a deeper understanding of genome-wide mechanisms involved in the long-term selection responses. The results illustrate that long-term selection responses, even from populations with a limited genetic diversity, can be polygenic and influenced by a range of genetic mechanisms.
Refractoriness accounts for variable spike burst responses in somatosensory cortex
Authors: Teleńczuk Bartosz , Kempter Richard , Curio Gabriel , Destexhe Alain
Published: January 2017

Neurons in the primary somatosensory cortex (S1) respond to peripheral stimulation with synchronised bursts of spikes, which lock to the macroscopic 600 Hz EEG waves. The mechanism of burst generation and synchronisation in S1 is not yet understood. Using models of single-neuron responses fitted to unit recordings from macaque monkeys, we show that these synchronised bursts are the consequence of correlated synaptic inputs combined with a refractory mechanism. In the presence of noise these models reproduce also the observed trial-to-trial response variability, where individual bursts represent one of many stereotypical temporal spike patterns. When additional slower and global excitability fluctuations are introduced the single-neuron spike patterns are correlated with the population activity, as demonstrated in experimental data. The underlying biophysical mechanism of S1 responses involves thalamic inputs arriving through depressing synapses to cortical neurons in a high-conductance state. Our findings show that a simple feedforward processing of peripheral inputs could give rise to neuronal responses with non-trivial temporal and population statistics. We conclude that neural systems could use refractoriness to encode variable cortical states into stereotypical short-term spike patterns amenable to processing at neuronal time scales (tens of milliseconds).

Significance statement

Neurons in the hand area of the primary somatosensory cortex respond to repeated presentation of the same stimulus with variable sequences of spikes, which can be grouped into distinct temporal spike patterns. In a simplified model, we show that such spike patterns are product of synaptic inputs and intrinsic neural properties. This model can reproduce both single-neuron and population responses only when a private variability in each neuron is combined with a multiplicative gain shared over whole population, which fluctuates over trials and might represent the dynamical state of the early stages of sensory processing. This phenomenon exemplifies a general mechanism of transforming the ensemble cortical states into precise temporal spike patterns at the level of single neurons.