bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors of Rowing Ergometer Performance in High-Level Female Rowers
Authors: Bourdin Muriel , Lacour Jean-Rene , Imbert Charles , Messonnier Laurent
Published: October 2017

The present study investigated morphological and physiological factors of rowing ergometer performance over 2000 m (P2000, W) in 70 national and international level [27 lightweight (LW) and 43 heavyweight (HW)] female rowers. Maximal oxygen uptake (V̇O2max, L.min−1), maximal aerobic power (Pamax, W), power output corresponding to 4 mmol.L−1 blood lactate concentration expressed in absolute (PLa4, W) and relative to Pamax (PLa4%, %) values, peak power output (Ppeak, W), and rowing gross efficiency (RGE, %) were determined during an incremental rowing test. In the whole group, Ppeak was the best predictor of P2000 (r=0.89, p<0.001), as it was shown in men. PLa4 (r=0.87), V̇O2max (r=0.83), body mass (r=0.65), and height (r=0.64) were also significantly correlated with P2000 (p<0.001 for all). Ppeak was also the best predictor of P2000 when the two sub-groups LW and HW were considered separately. It was concluded that Ppeak is an overall index of physiological rowing capacity in groups of high-level LW and HW female rowers. The predictive value of Ppeak is similar to that of PLa4, but Ppeak presents the advantage of being obtained with a simple ergometer test without biological measurements.
Erratum: Corrigendum: Misty, Spellbound and the lost Gothic of British girls’ comics
Authors: Round Julia
Published: October 2017

Correction to: Palgrave Communications (2017) 3 Article number: 17037 doi:10.1057/palcomms.2017.37; Published 16 May 2017; Updated 3 Oct 2017 On page 6 of the PDF, in the second paragraph beginning “I also surveyed Misty’s entire run of stories”, the sentence “However it does give a sense of the weighting given to named Gothic archetypes in Misty content—and reveals that they make up just 22% of its total content” has been corrected to “However it does give a sense of the weighting given to named Gothic archetypes in Misty—and reveals that these make up just 25% of its total comic strip content.
Connections between variation principles at the interface of wave-function and density-functional theories
Authors: Irons Tom J. P. , Furness James W. , Ryley Matthew S. , Zemen Jan , Helgaker Trygve , Teale Andrew M.
Published: October 2017

A recently proposed variation principle [N. I. Gidopoulos, Phys. Rev. A 83, 040502(R) (2011)] for the determination of Kohn–Sham effective potentials is examined and extended to arbitrary electron-interaction strengths and to mixed states. Comparisons are drawn with Lieb’s convex-conjugate functional, which allows for the determination of a potential associated with a given electron density by maximization, yielding the Kohn–Sham potential for a non-interacting system. The mathematical structure of the two functionals is shown to be intrinsically related; the variation principle put forward by Gidopoulos may be expressed in terms of the Lieb functional. The equivalence between the information obtained from the two approaches is illustrated numerically by their implementation in a common framework.
Multi-dimensional virtual system introduced to enhance canonical sampling
Authors: Higo Junichi , Kasahara Kota , Nakamura Haruki
Published: October 2017

When an important process of a molecular system occurs via a combination of two or more rare events, which occur almost independently to one another, computational sampling for the important process is difficult. Here, to sample such a process effectively, we developed a new method, named the “multi-dimensional Virtual-system coupled Monte Carlo (multi-dimensional-VcMC)” method, where the system interacts with a virtual system expressed by two or more virtual coordinates. Each virtual coordinate controls sampling along a reaction coordinate. By setting multiple reaction coordinates to be related to the corresponding rare events, sampling of the important process can be enhanced. An advantage of multi-dimensional-VcMC is its simplicity: Namely, the conformation moves widely in the multi-dimensional reaction coordinate space without knowledge of canonical distribution functions of the system. To examine the effectiveness of the algorithm, we introduced a toy model where two molecules (receptor and its ligand) bind and unbind to each other. The receptor has a deep binding pocket, to which the ligand enters for binding. Furthermore, a gate is set at the entrance of the pocket, and the gate is usually closed. Thus, the molecular binding takes place via the two events: ligand approach to the pocket and gate opening. In two-dimensional (2D)-VcMC, the two molecules exhibited repeated binding and unbinding, and an equilibrated distribution was obtained as expected. A conventional canonical simulation, which was 200 times longer than 2D-VcMC, failed in sampling the binding/unbinding effectively. The current method is applicable to various biological systems.
Ultrahigh capacitive energy storage in highly oriented Ba(ZrxTi1-x)O3 thin films prepared by pulsed laser deposition
Authors: Instan Alvaro A. , Pavunny Shojan P. , Bhattarai Mohan K. , Katiyar Ram S.
Published: October 2017

We report structural, optical, temperature and frequency dependent dielectric, and energy storage properties of pulsed laser deposited (100) highly textured BaZrxTi1−xO3 (x = 0.3, 0.4, and 0.5) relaxor ferroelectric thin films on La0.7Sr0.3MnO3/MgO substrates which make them potential lead-free capacitive energy storage materials for scalable electronic devices. A high dielectric constant of ∼1400–3500 and a low dielectric loss of <0.025 were achieved at 10 kHz for all three compositions at ambient conditions. Ultrahigh stored and recoverable electrostatic energy densities as high as 214 ± 1 and 156 ± 1 J/cm3, respectively, were demonstrated at a sustained high electric field of ∼3 MV/cm with an efficiency of 72.8 ± 0.6% in an optimum 30% Zr substituted BaTiO3 composition.
When shock is shocked: Riemann problem dynamics at pulse ionization of a shock wave
Authors: Doroshchenko Igor , Znamenskaya Irina , Koroteev Dmitry , Kuli-zade Tahir
Published: October 2017

We study the dynamics of the gas flow discontinuities after pulse ionization of a half space in front of a flat shock wave moving in a channel. Pulse volumetric electric discharge initiated in the vicinity of the shock concentrates in front of the shock and heats the gas there. The heating is shown to be very rapid. We use the shadow imaging technique and a high speed camera to study the flow pattern evolution after the discharge. The pattern consists of two shocks separated by a contact surface. This structure corresponds to the classical Riemann problem formulation. Based on the observed pattern, we estimate the amount of discharge energy converted to heat during the discharge time: the rate of temperature increase is in the order of several degrees K per nanosecond.
Note: Double-hole cantilevers for harmonic atomic force microscopy
Authors: Zhang Weijie , Chen Yuhang , Chu Jiaru
Published: October 2017

To enhance the harmonic signals in intermittent contact atomic force microscopy, we proposed the double-hole structural modification. Finite element analyses and experiments demonstrated the capability and advantages of the developed method. An infinite set of harmonic cantilevers can be optimized by proper selections of hole size, position, and inter-distance. The second and third resonance frequencies are simultaneously regulated to be integer multiples of the fundamental frequency. In the meanwhile, the alteration of cantilever stiffness is kept minimum. The double-hole modifications have prominent advantages of regular geometry, flexible selection of cutting positions/dimensions, and easy-to-meet fabrication tolerances.
In-situ probing of coupled atomic restructuring and metallicity of oxide heterointerfaces induced by polar adsorbates
Authors: Ryu S. , Zhou H. , Paudel T. R. , Irwin J. , Podkaminer J. P. , Bark C. W. , Lee D. , Kim T. H. , Fong D. D. , Rzchowski M. S. , Tsymbal E. Y. , Eom C. B.
Published: October 2017

Microscopic understanding of the surface-controlled conductivity of the two dimensional electron gas at complex oxide interfaces is crucial for developing functional interfaces. We observe conductivity and structural modification using in-situ synchrotron surface x-ray diffraction as the surface of a model LaAlO3/SrTiO3 (001) heterostructure is changed by polar adsorbates. We find that polar adsorbate-induced interfacial metallicity reduces polar distortions in the LaAlO3 layer. First-principles density functional theory calculations show that surface dipoles introduced by polar adsorbates lead to additional charge transfer and the reduction of polar displacements in the LaAlO3 layer, consistent with the experimental observations. Our study supports that internal structural deformations controlling functionalities can be driven without the application of direct electrical or thermal bias and offers a route to tuning interfacial properties. These results also highlight the important role of in-situ x-ray scattering with atomic resolution in capturing and exploring structural distortions and charge density changes caused by external perturbations such as chemical adsorption, redox reaction, and generation and/or annihilation of surface defects.
Detection and structural characterization of nitrosamide H2NNO: A central intermediate in deNOx processes
Authors: McCarthy Michael C. , Lee Kin Long Kelvin , Stanton John F.
Published: October 2017

The structure and bonding of H2NNO, the simplest N-nitrosamine, and a key intermediate in deNOx processes, have been precisely characterized using a combination of rotational spectroscopy of its more abundant isotopic species and high-level quantum chemical calculations. Isotopic spectroscopy provides compelling evidence that this species is formed promptly in our discharge expansion via the NH2 + NO reaction and is collisionally cooled prior to subsequent unimolecular rearrangement. H2NNO is found to possess an essentially planar geometry, an NNO angle of 113.67(5)°, and a N–N bond length of 1.342(3) Å; in combination with the derived nitrogen quadrupole coupling constants, its bonding is best described as an admixture of uncharged dipolar (H2N–N=O, single bond) and zwitterion (H2N+=N–O−, double bond) structures. At the CCSD(T) level, and extrapolating to the complete basis set limit, the planar geometry appears to represent the minimum of the potential surface, although the torsional potential of this molecule is extremely flat.
Development of the saddle loop sensors on the J-TEXT tokamak
Authors: Guo Daojing , Hu Qiming , Li Da , Wang Nengchao , Ding Yonghua , Shen Chengshuo , Huang Zhuo , Xu Guo , Yu Qingquan , Tang Yuejin , Zhuang Ge
Published: October 2017

To measure the amplitude and phase of the non-axisymmetric radial magnetic field generated by the locked mode, 12 saddle loop sensors are newly developed on the J-TEXT Tokamak. The saddle loop is made of flexible printed circuit (FPC) to adapt the complex installment environment and ensure the installment accuracy. In the experiment, the saddle loop measures the radial magnetic field of locked mode and the axisymmetric equilibrium magnetic fields as well as that of the corresponding eddy current. Precise compensation for the fluxes induced by the horizontal and vertical field coils is realized by utilizing the lumped eddy current circuits based on an analytical model. By using this set of saddle loop sensors, the amplitude and phase of the m/n = 2/1 locked mode are clearly measured for the case of error field locking with slow rotation and the penetration of resonant magnetic perturbations (RMPs) respectively. Here, m and n are the poloidal and toroidal mode number.
Transient lateral photovoltaic effect in synthetic single crystal diamond
Authors: Prestopino G. , Marinelli M. , Milani E. , Verona C. , Verona-Rinati G.
Published: October 2017

A transient lateral photovoltaic effect (LPE) is reported for a metal-semiconductor structure of synthetic single crystal diamond (SCD). A SCD Schottky photodiode was specifically designed to measure a LPE under collimated irradiation from a tunable pulsed laser. A transient lateral photovoltage parallel to the Schottky junction was indeed detected. LPE on the p-type doped SCD side showed a non-linearity of 2% and a fast response time, with a rise time of 2 μs and a decay time of 12 μs. The position sensitivity (up to 30 mV/mm at a laser wavelength of 220 nm and a pulse energy density of 2.9 μJ/mm2) was measured as a function of laser wavelength, and an ultraviolet (UV)-to-visible contrast ratio of about four orders of magnitude with a sharp cutoff at 225 nm was observed. Our results demonstrate that a large LPE at UV wavelengths is achievable in synthetic single crystal diamond, potentially opening opportunities for the study and application of LPE in diamond and for the fabrication of high performance visible blind UV position sensitive detectors with high sensitivity and microsecond scale response time.
Excitation energies from particle-particle random phase approximation with accurate optimized effective potentials
Authors: Jin Ye , Yang Yang , Zhang Du , Peng Degao , Yang Weitao
Published: October 2017

The optimized effective potential (OEP) that gives accurate Kohn-Sham (KS) orbitals and orbital energies can be obtained from a given reference electron density. These OEP-KS orbitals and orbital energies are used here for calculating electronic excited states with the particle-particle random phase approximation (pp-RPA). Our calculations allow the examination of pp-RPA excitation energies with the exact KS density functional theory (DFT). Various input densities are investigated. Specifically, the excitation energies using the OEP with the electron densities from the coupled-cluster singles and doubles method display the lowest mean absolute error from the reference data for the low-lying excited states. This study probes into the theoretical limit of the pp-RPA excitation energies with the exact KS-DFT orbitals and orbital energies. We believe that higher-order correlation contributions beyond the pp-RPA bare Coulomb kernel are needed in order to achieve even higher accuracy in excitation energy calculations.
Active chiral control of GHz acoustic whispering-gallery modes
Authors: Mezil Sylvain , Fujita Kentaro , Otsuka Paul H. , Tomoda Motonobu , Clark Matt , Wright Oliver B. , Matsuda Osamu
Published: October 2017

We selectively generate chiral surface-acoustic whispering-gallery modes in the gigahertz range on a microscopic disk by means of an ultrafast time-domain technique incorporating a spatial light modulator. Active chiral control is achieved by making use of an optical pump spatial profile in the form of a semicircular arc, positioned on the sample to break the symmetry of clockwise- and counterclockwise-propagating modes. Spatiotemporal Fourier transforms of the interferometrically monitored two-dimensional acoustic fields measured to micron resolution allow individual chiral modes and their azimuthal mode order, both positive and negative, to be distinguished. In particular, for modes with 15-fold rotational symmetry, we demonstrate ultrafast chiral control of surface acoustic waves in a micro-acoustic system with picosecond temporal resolution. Applications include nondestructive testing and surface acoustic wave devices.
Polarization tunable photogenerated carrier transfer of CH3NH3PbI3/polyvinylidene fluoride heterostructure
Authors: Yang Kang , Deng Zun-Yi , Feng Hong-Jian
Published: October 2017

The integration of ferroelectrics and organic-inorganic halide perovskites could be a promising way to facilitate the separation of electron-hole pairs and charge extraction for the application of solar cells. To explore the effect of the external ferroelectric layer on the CH3NH3PbI3 (MAPbI3) side, we perform first-principles calculations to study the charge transfer properties of the MAPbI3/polyvinylidene fluoride (PVDF) heterostructure. Our calculations demonstrate that the ferroelectric polarization pointing to the PVDF side can clearly facilitate the separation of photo-induced carriers and enhance charge extraction from MAPbI3, while opposite polarization direction hinders the charge extraction and collection. Notably, the carrier behavior at the interface is strongly tuned by the electric field associated with the ferroelectric polarization. In addition, excited state simulation confirms the tunable charge transfer of the MAPbI3/PVDF heterojunction. Therefore, the polarization-driven charge transfer mechanism provides a route for fabricating the ferroelectrics-based high-efficiency photovoltaics and switchable diode devices.
Transports in a rough ratchet induced by Lévy noises
Authors: Li Yongge , Xu Yong , Kurths Juergen , Yue Xiaole
Published: October 2017

We study the transport of a particle subjected to a Lévy noise in a rough ratchet potential which is constructed by superimposing a fast oscillating trigonometric function on a common ratchet background. Due to the superposition of roughness, the transport process exhibits significantly different properties under the excitation of Lévy noises compared to smooth cases. The influence of the roughness on the directional motion is explored by calculating the mean velocities with respect to the Lévy stable index α and the spatial asymmetry parameter q of the ratchet. Variations in the splitting probability have been analyzed to illustrate how roughness affects the transport. In addition, we have examined the influences of roughness on the mean first passage time to know when it accelerates or slows down the first passage process. We find that the roughness can lead to a fast reduction of the absolute value of the mean velocity for small α, however the influence is small for large α. We have illustrated that the ladder-like roughness on the potential wall increases the possibility for particles to cross the gentle side of the ratchet, which results in an increase of the splitting probability to right for the right-skewed ratchet potential. Although the roughness increases the corresponding probability, it does not accelerate the mean first passage process to the right adjacent well. Our results show that the influences of roughness on the mean first passage time are sensitive to the combination of q and α. Hence, the proper q and α can speed up the passage process, otherwise it will slow down it.
Spin switch in iron phthalocyanine on Au(111) surface by hydrogen adsorption
Authors: Wang Yu , Li Xiaoguang , Zheng Xiao , Yang Jinlong
Published: October 2017

The manipulation of spin states at the molecular scale is of fundamental importance for the development of molecular spintronic devices. One of the feasible approaches for the modification of a molecular spin state is through the adsorption of certain specific atoms or molecules including H, NO, CO, NH3, and O2. In this paper, we demonstrate that the local spin state of an individual iron phthalocyanine (FePc) molecule adsorbed on an Au(111) surface exhibits controllable switching by hydrogen adsorption, as evidenced by using first-principles calculations based on density functional theory. Our theoretical calculations indicate that different numbers of hydrogen adsorbed at the pyridinic N sites of the FePc molecule largely modify the structural and electronic properties of the FePc/Au(111) composite by forming extra N–H bonds. In particular, the adsorption of one or up to three hydrogen atoms induces a redistribution of charge (spin) density within the FePc molecule, and hence a switching to a low spin state (S = 1/2) from an intermediate spin state (S = 1) is achieved, while the adsorption of four hydrogen atoms distorts the molecular conformation by increasing Fe–N bond lengths in FePc and thus breaks the ligand field exerted on the Fe 3d orbitals via stronger hybridization with the substrate, leading to an opposite switching to a high-spin state (S = 2). These findings obtained from the theoretical simulations could be useful for experimental manipulation or design of single-molecule spintronic devices.
Mixing of MnPc electronic states at the MnPc/Au(110) interface
Authors: Gargiani Pierluigi , Lisi Simone , Avvisati Giulia , Mondelli Pierluigi , Fatale Sara , Betti Maria Grazia
Published: October 2017

Manganese-phthalocyanines form assembled chains with a variety of ordered super-structures, flat lying along the Au(110) reconstructed channels. The chains first give rise to a ×5 symmetry reconstruction, while further deposition of MnPc leads to a ×7 periodicity at the completion of the first single layer. A net polarization with the formation of an interface dipole is mainly due to the molecular π-states located on the macrocycles pyrrole rings, while the central metal ion induces a reduction in the polarization, whose amount is related to the Mn-Au interaction. The adsorption-induced interface polarization is compared to other 3d-metal phthalocyanines, to unravel the role of the central metal atom configuration in the interaction process of the d-states. The MnPc adsorption on Au(110) induces the re-hybridization of the electronic states localized on the central metal atom, promoting a charge redistribution of the molecular orbitals of the MnPc molecules. The molecule-substrate interaction is controlled by a symmetry-determined mixing between the electronic states, involving also the molecular empty orbitals with d character hybridized with the nitrogen atoms of the pyrrole ring, as deduced by photoemission and X-ray absorption spectroscopy exploiting light polarization. The symmetry-determined mixing between the electronic states of the Mn metal center and of the Au substrate induces a density of states close to the Fermi level for the ×5 phase.
Prevention of surface recombination by electrochemical tuning of TiO2-passivated photocatalysts
Authors: Hou Bingya , Rezaeifar Fatemeh , Qiu Jing , Zeng Guangtong , Kapadia Rehan , Cronin Stephen B.
Published: October 2017

We present a systematic study of photoluminescence (PL) spectroscopy of TiO2-passivated GaAs as a function of electrochemical potential in an ionic liquid solution. We observe a 7X increase in the PL intensity as the GaAs transitions from accumulation to depletion due to the applied potential. We attribute this to the excellent control over the surface Fermi level enabled by the high capacitance of the electrochemical double layer and TiO2. This allows us to control the surface carrier concentration and corresponding non-radiative recombination rate. In addition to photoluminescence (PL) spectroscopy, we also measured the capacitance-potential (i.e., C-V) characteristics of these samples, which indicate flat band potentials that are consistent with these regimes of ion accumulation observed in the photoluminescence measurements. We have also performed electrostatic simulations of these C-V characteristics, which provide a detailed and quantitative picture of the conduction and valence band profiles and charge distribution at the surface of the semiconductor. These simulations also enable us to determine the range of potentials over which the semiconductor surface experiences depletion, inversion, and accumulation of free carriers. Based on these simulations, we can calculate the Shockley-Read-Hall recombination rate and model the PL intensity as a function of voltage. We show that this approach allows us to explain our experimental data well.
Ferroelectricity in Lu doped HfO2 layers
Authors: Tromm T. C. U. , Zhang J. , Schubert J. , Luysberg M. , Zander W. , Han Q. , Meuffels P. , Meertens D. , Glass S. , Bernardy P. , Mantl S.
Published: October 2017

Doped HfO2 has become a promising candidate for non-volatile memory devices since it can be easily integrated into existing CMOS technology. Many dopants like Y, Gd, and Sr have been investigated for the stabilization of ferroelectric HfO2. Here, we report the fabrication of capacitors comprising ferroelectric HfO2 metal-insulator-metal structures with TiN bottom and top electrodes using the dopant Lu. Amorphous 5% Lu doped HfO2 was deposited by pulsed laser deposition and afterwards annealed to achieve the ferroelectric, orthorhombic phase (space group Pbc21). The polarization of the layers was confirmed by capacitance-voltage, polarization-voltage, and current-voltage measurements. Depending on the anneal temperature, the remanent polarization changes and the initial state of the oxide varies. The layer exhibits initially a pinched hysteresis up to an annealing temperature of 600 °C and an unpinched hysteresis at 700 °C. The maximum polarization is about 11 μC/cm2 which is measured after 104 cycles and stable up to 106 cycles. The influence of the layer thickness on the oxide properties is investigated for 10–40 nm thick HfLuO; however, a thickness dependence of the ferroelectric properties is not observed.
Determination of stress-coefficient of magnetoelastic anisotropy in flexible amorphous CoFeB film by anisotropic magnetoresistance
Authors: Wen Xingcheng , Wang Baomin , Sheng Ping , Hu Shuai , Yang Huali , Pei Ke , Zhan Qingfeng , Xia Weixing , Xu Hui , Li Run-Wei
Published: October 2017

Flexible magnetic devices are one of the indispensable flexible devices. However, the deformation of the magnetic devices will change the magnetic anisotropy of magnetic materials due to magnetoelastic anisotropy, which will decrease the performance of the devices. Therefore, it is essential to determine the stress-coefficient of magnetoelastic anisotropy in magnetic materials. Here, the magnetic anisotropy constants of an amorphous CoFeB film on a flexible polyvinylidene fluoride (PVDF) substrate in different stress states were quantitatively investigated by anisotropic magnetoresistance (AMR). The enhanced magnetic anisotropy of the CoFeB film at reduced temperature is due to magnetoelastic anisotropy induced by anisotropic thermal expansion of the PVDF substrate. Through fitting the AMR curves under variant fields in different stress states, the stress-coefficient of magnetoelastic anisotropy in the amorphous CoFeB film is obtained to be 170.7 × 103 erg cm−3 GPa−1.
A precision structured smart hydrogel for sensing applications
Authors: Menges J. , Kleinschmidt P. , Bart H.-J. , Oesterschulze E.
Published: October 2017

We report on a macroinitiator based smart hydrogel film applied on a microcantilever for sensing applications. The studied hydrogel features a comparatively wide dynamic range for changes in the electrolyte's ionic strength. Furthermore, it offers a simple spin coating process for thin film deposition as well as the capability to obtain high aspect ratio microstructures by reactive ion etching. This makes the hydrogel compatible to microelectromechanical system integration. As a proof of concept, we study the response of hydrogel functionalized cantilevers in aqueous sodium chloride solutions of varying ionic strength. In contrast to the majority of hydrogel materials reported in the literature, we found that our hydrogel still responds in high ionic strength environments. This may be of future interest for sensing e.g., in sea water or physiological environments like urine.
Domain wall motion in a nanoconstriction of Gd
Authors: Chakravorty Manotosh , Raychaudhuri A. K.
Published: October 2017

We report the observation of a DC-current driven magnetic domain wall (DW) motion in an artificially created nanoconstriction (size ∼ 300 nm) in a microstrip of 4f ferromagnet Gd (film thickness, 40 nm), where beyond a critical current density, a sharp reduction in the resistance is observed which gives the DW resistance RW. This is similar to that seen in nanoconstrictions made in conventional 3d ferromagnets such as Ni and its alloys. The effect is most prominent at 100 K or below and becomes smaller as the temperature increases, and it vanishes as T→TC. The value of RW was used in conjunction with the measured anisotropic magnetoresistance to find the domain wall thickness (δ) and the anisotropy energy (EA) of the Gd film. The observation of this phenomenon in 4f metal Gd, which is distinct from itinerant conventional 3d transition metals, extends the phenomena to rare-earth ferromagnets. A low ferromagnetic transition temperature of Gd also allows us to study the phenomena and the evolution of δ and EA as a function of temperature.
Exceptional points make for exceptional sensors
Authors: Miller Johanna L.
Published: October 2017

At just the right locations in parameter space, resonant frequencies are ultrasensitive to tiny changes in conditions.
First physicist in Congress dies
Authors: Kramer David
Published: October 2017

Vernon Ehlers, former House member from Michigan, was a strong advocate for improved science education.
Ultraperipheral nuclear collisions
Authors: Klein Spencer , Nystrand Joakim
Published: October 2017

When nuclei at particle accelerators just miss each other, the short-range strong force is mitigated and photon interactions come to the fore.
The new era of polariton condensates
Authors: Snoke David W. , Keeling Jonathan
Published: October 2017

Quasiparticles of light and matter may be our best hope for harnessing the strange effects of quantum condensation and superfluidity in everyday applications.
N,N-Dialkyl-N′-Chlorosulfonyl Chloroformamidines in Heterocyclic Synthesis. Part XIV. Synthesis and Reactivity of the New Benzo[4,5]imidazo[1,2-b][1,2,6]thiadiazine Ring System
Authors: Innes Dylan , Perkins Michael V. , Liepa Andris J. , Francis Craig L.
Published: October 2017

N,N-Dialkyl-N′-chlorosulfonyl chloroformamidines 1 underwent regioselective reactions with the 1,3-NCC bis-nucleophilic 1H-benzimidazole-2-acetonitriles 4 and related compounds to produce benzo[4,5]imidazo[1,2-b][1,2,6]thiadiazine dioxides 6, 9, 12, and 14, representatives of a new ring system. Reaction of dichlorides 1 with trifluoroacetyl derivative 16 afforded benzo[4,5]imidazo[1,2-c]pyrimidines 19 and 20. An N-acyl and some N-alkyl derivatives of benzimidazo-thiadiazines 6 were prepared to demonstrate the potential of this new ring system as a novel scaffold for synthetic and medicinal chemistry applications. Treatment of the 4-cyano-5-methyl-benzimidazo-thiadiazine 26c with LiAlH4 resulted in an unexpected and remarkable conversion of the nitrile to give the 4,5-dimethyl-benzimidazo-thiadiazine 29.
Seasonal effects on body temperature of the endangered grassland earless dragon, Tympanocryptis pinguicolla, from populations at two elevations
Authors: Nelson Lyn S. , Cooper Paul D.
Published: October 2017

The endangered grassland earless dragon, Tympanocryptis pinguicolla, is present in two geographic locations in Australia: the Australian Capital Territory and adjacent New South Wales (NSW) near Canberra (~580 m above sea level) and Monaro Plains, NSW, near Cooma (~950 m above sea level). The lizards live in native grassland, an endangered ecological community, and although the population ecology of the animal has been examined, the importance of habitat for thermoregulatory patterns is unknown. We studied whether lizards from the two locations differ in their seasonal patterns of thermoregulation by measuring skin and chest temperatures using both radio-telemetry and temperature measurement in the field, as well as thermal preferences in a laboratory thermal gradient. These results are compared with the operative temperatures (Te) in various microhabitats in the two regions to determine to what extent lizards are thermoregulating. We demonstrate that these lizards do not maintain a constant body temperature, but allow Tb to vary between 13 and 39°C when active in the field, although the grand mean for 50% basking temperatures ranged between 32 and 36°C in the laboratory gradient. Temperatures in the various microhabitats can exceed 40°C, but lizards appeared to avoid those temperatures by seeking shelter in either burrows or the base of grass tussocks. Lizards could choose microhabitats that would permit maintenance of body temperatures above 30°C in most seasons, but did not do so. As high body temperature is not selected in field conditions for either population, other processes (e.g. predation) may be more important for determining Tb maintenance.
Proteasome-independent polyubiquitin linkage regulates synapse scaffolding, efficacy, and plasticity
Authors: Ma Qi , Ruan Hongyu , Peng Lisheng , Zhang Mingjie , Gack Michaela U. , Yao Wei-Dong
Published: October 2017

Significance

A well-investigated mechanism regulating synapse protein turnover and remodeling is the classical ubiquitin–proteasome system by which polyubiquitin (polyUb) chains linked through ubiquitin lysine 48 (K48) tag substrates for proteasomal degradation. Little is known about the role of nondegradable polyUb linkages, e.g., K63-linked chains, in the synapse, although these chains represent the second most abundant polyUb linkage in mammalian brain. We identified a bona fide K63-polyUb substrate in PSD-95, a major postsynaptic scaffold. K63-polyUb conjugation markedly augments PSD-95’s scaffolding capability and promotes its synaptic targeting and anchorage. We identify a K63-linkage–specific E3 ligase–deubiquitinase complex that controls activity-dependent assembly and disassembly of K63-polyUb chains on PSD-95. We show that this unconventional polyUb linkage promotes synapse maturation, efficacy, and plasticity.
Actin retrograde flow actively aligns and orients ligand-engaged integrins in focal adhesions
Authors: Swaminathan Vinay , Kalappurakkal Joseph Mathew , Mehta Shalin B. , Nordenfelt Pontus , Moore Travis I. , Koga Nobuyasu , Baker David A. , Oldenbourg Rudolf , Tani Tomomi , Mayor Satyajit , Springer Timothy A. , Waterman Clare M.
Published: October 2017

Significance

Integrins are adhesion receptors linking cells to their environment, which function as sensors of physical and chemical information to regulate development, immune response, and vascular function. How integrins receive and transduce directional forces including flow or tissue tension has remained elusive. We used polarization-based microscopy techniques to discover that activated αVβ3 integrins are aligned with one another in focal adhesions in migrating fibroblasts. Integrin coalignment is sensitive to mechanical resistance of its ligand and coupling to a dynamic F-actin cytoskeleton, consistent with the “cytoskeleton force model” for integrin activation. Our work suggests that activated integrins are actively ordered at the molecular scale by cellular forces, which may underlie their ability to sense directional forces in their environment to mediate critical functions.
Long-term restoration of visual function in end-stage retinal degeneration using subretinal human melanopsin gene therapy
Authors: De Silva Samantha R. , Barnard Alun R. , Hughes Steven , Tam Shu K. E. , Martin Chris , Singh Mandeep S. , Barnea-Cramer Alona O. , McClements Michelle E. , During Matthew J. , Peirson Stuart N. , Hankins Mark W. , MacLaren Robert E.
Published: October 2017

Significance

Inherited retinal degenerations may result in blindness due to a progressive loss of photoreceptor cells. We assess subretinal delivery of human melanopsin using an adeno-associated viral vector to remaining retinal cells in a model of end-stage retinal degeneration. Human melanopsin, being already present in the eye, is unlikely to generate an immune response when introduced via gene therapy. Furthermore, this method of delivery has been proven to be safe in clinical trials and may be more effective at delivering vector in primates than the alternative method of intravitreal injection. We demonstrate long-term vector expression and restoration of visual function, indicating that this therapy could be stable and efficacious in the treatment of patients with end-stage retinal degenerations.
Cross-activating c-Met/β1 integrin complex drives metastasis and invasive resistance in cancer
Authors: Jahangiri Arman , Nguyen Alan , Chandra Ankush , Sidorov Maxim K. , Yagnik Garima , Rick Jonathan , Han Sung Won , Chen William , Flanigan Patrick M. , Schneidman-Duhovny Dina , Mascharak Smita , De Lay Michael , Imber Brandon , Park Catherine C. , Matsumoto Kunio , Lu Kan , Bergers Gabriele , Sali Andrej , Weiss William A. , Aghi Manish K.
Published: October 2017

Significance

Invasion is a major cause of cancer mortality, as exemplified by metastatic spread of peripheral malignancies or local intracranial invasion of glioblastoma. While individual mediators of invasion are identified, functional or structural interactions between these mediators remain undefined. We identified a structural cross-activating c-Met/β1 integrin complex that promotes breast cancer metastases and invasive resistance of glioblastoma to the antiangiogenic therapy bevacizumab. We show that tumor cells adapt to their microenvironmental stressors by usurping c-Met and β1 integrin, with c-Met displacing α5 integrin from β1 integrin to form a c-Met/β1 complex with far greater fibronectin affinity than α5β1 integrin. These findings challenge conventional thinking about integrin–ligand interactions and define a molecular target for disrupting metastases or invasive oncologic resistance.
Autophagy is required for endothelial cell alignment and atheroprotection under physiological blood flow
Authors: Vion Anne-Clemence , Kheloufi Marouane , Hammoutene Adel , Poisson Johanne , Lasselin Juliette , Devue Cecile , Pic Isabelle , Dupont Nicolas , Busse Johanna , Stark Konstantin , Lafaurie-Janvore Julie , Barakat Abdul I. , Loyer Xavier , Souyri Michele , Viollet Benoit , Julia Pierre , Tedgui Alain , Codogno Patrice , Boulanger Chantal M. , Rautou Pierre-Emmanuel
Published: October 2017

Significance

Atherosclerotic plaques tend to develop preferentially in areas of the vasculature exposed to low and disturbed shear stress (SS), but the mechanisms are not fully understood. In this study, we demonstrate that inefficient autophagy contributes to the development of atherosclerotic plaques in low-SS areas. Defective endothelial autophagy not only curbs endothelial alignment with the direction of blood flow, but also promotes an inflammatory, apoptotic, and senescent phenotype. Furthermore, genetic inactivation of endothelial autophagy in a murine model of atherosclerosis increases plaque burden exclusively in high-SS areas that are normally resistant to atherosclerotic plaque development. Altogether, these findings underline the role of endothelial autophagic flux activation by SS as an atheroprotective mechanism.
Interhost dispersal alters microbiome assembly and can overwhelm host innate immunity in an experimental zebrafish model
Authors: Burns Adam R. , Miller Elizabeth , Agarwal Meghna , Rolig Annah S. , Milligan-Myhre Kathryn , Seredick Steve , Guillemin Karen , Bohannan Brendan J. M.
Published: October 2017

Significance

Manipulating the microbial communities associated with animals to improve host health requires a comprehensive understanding of the mechanisms driving microbiome variation, which a strict focus on host-specific factors has been insufficient in providing. We performed an experiment to test whether the movement, or dispersal, of microorganisms among zebrafish hosts could alter the effects of important host factors, using a dispersal-based model to guide the interpretation of results. We observed that interhost dispersal can alter the diversity and composition of microbial communities and overwhelm the effects of the host’s innate immune system. These findings suggest that dispersal is an important mechanism driving microbiome variation and should be considered in future microbiome research.
YAP/TAZ-CDC42 signaling regulates vascular tip cell migration
Authors: Sakabe Masahide , Fan Jieqing , Odaka Yoshinobu , Liu Ning , Hassan Aishlin , Duan Xin , Stump Paige , Byerly Luke , Donaldson Megan , Hao Jiukuan , Fruttiger Marcus , Lu Qing Richard , Zheng Yi , Lang Richard A. , Xin Mei
Published: October 2017

Significance

New blood vessel formation is a physiological process seen in development, as well as in wound healing and tumorigenesis. Although the process of blood vasculature formation has been well documented, little is known about the molecular mechanisms that regulate endothelial migration during vascular network formation. In this study, we identified a critical role for Hippo effectors YAP and TAZ in the regulation of vascular network remodeling through controlling endothelial cell (EC) proliferation, filopodia formation, and cell migration. We found a striking cytoplasmic function of YAP in the regulation of EC migration through controlling the Rho family GTPase CDC42 activity. These findings identify a previously unrecognized YAP/TAZ function involved in the vascular network remodeling during angiogenesis.
Asynchronous warming and δ
18
O evolution of deep Atlantic water masses during the last deglaciation
Authors: Zhang Jiaxu , Liu Zhengyu , Brady Esther C. , Oppo Delia W. , Clark Peter U. , Jahn Alexandra , Marcott Shaun A. , Lindsay Keith
Published: October 2017

Significance

The reorganizations of deep Atlantic water masses are widely thought to regulate glacial–interglacial climate changes. However, the pattern of reorganizations and their impact on ocean tracer transport remain poorly constrained by marine proxies. Our modeling study, which simulates the coevolution of water masses and oxygen isotopes during the last deglaciation, suggests that deglacial meltwater input causes both northern- and southern-sourced deep water transports to decrease. This reorganization pattern leads to asynchronous warming between the deep North and South Atlantic, which might have caused the observed deglacial phasing difference in deep water oxygen isotope records between these ocean basins. We further propose a mechanism to explain the early warming in the northern North Atlantic.
Spontaneous self-dislodging of freezing water droplets and the role of wettability
Authors: Graeber Gustav , Schutzius Thomas M. , Eghlidi Hadi , Poulikakos Dimos
Published: October 2017

Significance

Freezing of water on surfaces is ubiquitous in nature and technology; however, to control ice aggregation and rationally design icephobic surfaces, which passively inhibit ice formation and accretion, a deeper fundamental understanding of the interaction of forming ice with the underlying substrate and environment is necessary. In this work, we report the phenomenon of self-dislodging freezing water droplets, explain its physics, and develop surfaces which inhibit ice aggregation through passive ice self-removal. Successful experiments on a palette of material classes underpin the general applicability and robustness of the effect to control surface icing, and can guide further research in the field of icephobicity.
Why pens have rubbery grips
Authors: Dzidek Brygida , Bochereau Séréna , Johnson Simon A. , Hayward Vincent , Adams Michael J.
Published: October 2017

Significance

Why does gripping a pen, tool, or handle feel more secure when it is coated with a rubbery material? The keratin of the skin outer layer is stiff and rough at a small scale. When encountering a smooth, stiff, and impermeable surface, such as polished metal or glass, the actual contact area is initially small as is the friction. Because the keratin softens when it is hydrated by the moisture secreted from the sweat pores, it requires many seconds for the contact area to increase to the value reached almost instantaneously with a soft material, such as a rubber. This mechanism might be used by our tactile sense to identify materials and has implications for the design of tactile displays.
Soilborne fungi have host affinity and host-specific effects on seed germination and survival in a lowland tropical forest
Authors: Sarmiento Carolina , Zalamea Paul-Camilo , Dalling James W. , Davis Adam S. , Stump Simon M. , U’Ren Jana M. , Arnold A. Elizabeth
Published: October 2017

Significance

The remarkable diversity of trees in tropical forests is thought to be maintained by natural enemies such as fungal pathogens, which must exhibit sufficient host specificity to differentially impact survival of co-occurring host species. Little is known about the specificity of fungi that infect seeds of tropical trees. Here we show that communities of seed-associated fungi are structured more by plant species than by soil type, forest characteristics, or time in soil. These fungi have host-specific impacts on seed viability and germination. In this way, highly diverse communities of soilborne fungi directly impact a critical component of reproduction in tropical trees—seeds—with the potential to contribute to maintaining diversity in some of the richest terrestrial communities on Earth.
Period2
3′-UTR and microRNA-24 regulate circadian rhythms by repressing PERIOD2 protein accumulation
Authors: Yoo Seung-Hee , Kojima Shihoko , Shimomura Kazuhiro , Koike Nobuya , Buhr Ethan D. , Furukawa Tadashi , Ko Caroline H. , Gloston Gabrielle , Ayoub Christopher , Nohara Kazunari , Reyes Bryan A. , Tsuchiya Yoshiki , Yoo Ook-Joon , Yagita Kazuhiro , Lee Choogon , Chen Zheng , Yamazaki Shin , Green Carla B. , Takahashi Joseph S.
Published: October 2017

Significance

The circadian oscillator is a cell-autonomous biological timer driving daily physiological rhythms to ensure fitness and health. Regulatory mechanisms of the oscillator are complex and not fully understood. We previously generated two circadian reporter mouse lines that differ only in the 3′-UTR region of the core clock gene
Per2
. Interestingly, substitution of the endogenous
Per2
3′-UTR with an SV40 late poly(A) signal led to a lengthened period, enhanced PER2 protein level, and more robust oscillatory amplitude. PER2 also displayed a positive role in circadian transcription. Molecular and genetic studies showed the microRNA miR-24 binds to the
Per2
3′-UTR to attenuate rhythmic PER2 accumulation. These results identified an important posttranscriptional regulatory mechanism of PER2 expression required for normal circadian timekeeping.
Semisynthetic glycoconjugate vaccine candidate against
Streptococcus pneumoniae
serotype 5
Authors: Lisboa Marilda P. , Khan Naeem , Martin Christopher , Xu Fei-Fei , Reppe Katrin , Geissner Andreas , Govindan Subramanian , Witzenrath Martin , Pereira Claney L. , Seeberger Peter H.
Published: October 2017

Significance

Each year,
Streptococcus pneumoniae
infections cause millions of deaths worldwide. The capsular polysaccharide (CPS) based glycoconjugate vaccine Prevnar13 prevents serious illness caused by 13 serotypes.
S. pneumoniae
serotype 5 (ST-5) is included in the vaccine; however, it suffers from production problems due to modifications or degradation during isolation and conjugation. A medicinal chemistry approach helped to understand the structural features of ST-5 CPS and design a stable semisynthetic oligosaccharide-based vaccine candidate. Oligosaccharide leads for immunological evaluations in vivo were identified employing glycan microarrays. The stable monovalent ST-5 oligosaccharide glycoconjugate vaccine candidate showed a superior immune response in rabbits when compared with the ST-5 CPS present in the multivalent vaccine Prevnar13.
CLOCK stabilizes CYCLE to initiate clock function in
Drosophila
Authors: Liu Tianxin , Mahesh Guruswamy , Yu Wangjie , Hardin Paul E.
Published: October 2017

Significance

The
Drosophila
circadian clock controls daily rhythms in physiology, metabolism, and behavior via ∼24-h transcriptional feedback loops. CLOCK requires its heterodimeric partner CYCLE to initiate clock function in canonical groups of brain neurons and peripheral tissues, but
Clock
expression can also induce clocks in ectopic locations. Here, we show that CLOCK stabilizes CYCLE in canonical and ectopic clock cells, where CYCLE is normally rapidly degraded, and that ectopic clocks also require CRYPTOCHROME. This work defines the genetic architecture and molecular mechanisms required for clock initiation that are likely conserved in other eukaryotes and suggests that ectopic clocks can be generated by
Clock
,
cycle
, and
cryptochrome
expression in naive cells.