bluuebunny/crossref_metadata_2025 huggingface dataset:
Revising the common understanding of metamagnetism in the molecule-based bisdithiazolyl BDTMe compound
Authors: Climent Clàudia , Vela Sergi , Jornet-Somoza Joaquim , Deumal Mercè
Published: May 2019

The metamagnetism of sulfur–nitrogen heterocyclic BDTMe material is interpreted in terms of the Boltzman-population of states and tuned by weak antiferromagnetic interactions within its 3D ferromagnetic topology.
Adsorption of water and n-hexane on pristine and oxidized carbon nanotube supports of cobalt-based Fischer–Tropsch catalysts
Authors: Chernyak Sergei A. , Strokova Natalia E. , Fedorova Elizaveta S. , Ivanov Anton S. , Maslakov Konstantin I. , Savilov Serguei V. , Lunin Valery V.
Published: May 2019

Adsorption of water and n-hexane by oxidized and pristine CNTs at different stages of Co/CNT catalyst preparation has been studied to reveal the effect of the support surface functionalization on the catalyst selectivity in Fischer–Tropsch synthesis.
Ionic liquid thin layer-induced memory effects in organic field-effect transistors
Authors: Eguchi Keitaro , Matsushita Michio M. , Awaga Kunio
Published: May 2019

Ionic liquid layers affect the morphology of organic semiconductors, grown on them, and induce memory effects in organic FETs.
Photoactive platinum(iv) complex conjugated to a cancer-cell-targeting cyclic peptide
Authors: Shi Huayun , Wang Qian , Venkatesh V. , Feng Guokai , Young Lawrence S. , Romero-Canelón Isolda , Zeng Musheng , Sadler Peter J.
Published: May 2019

Conjugate of a cancer-cell targeting cyclic peptide with a photoactive platinum(iv) complex exhibits enhanced photocytotoxicity and cell accumulation.
Flow-based enzymatic synthesis of melatonin and other high value tryptamine derivatives: a five-minute intensified process
Authors: Contente Martina Letizia , Farris Stefano , Tamborini Lucia , Molinari Francesco , Paradisi Francesca
Published: May 2019

To increase the uptake of biocatalytic processes by industry, it is essential to demonstrate the reliability of enzyme-based methodologies directly applied to the production of high value products.
A FRET-based colorimetric and ratiometric fluorescent probe for the detection of Cu2+with a new trimethylindolin fluorophore
Authors: Zhang Jiao , Zhu Mei , Jiang Daoyong , Zhang Han , Li Luying , Zhang Guoning , Wang Yucheng , Feng Chao , Zhao Hong
Published: May 2019

The possible interaction mechanism between probeRhFand Cu2+ions.
meso-Aryl substituted stable unorthodox 5,10-porphodimethenes with α,β and β,β-N-methyl pyrrole connectivities: synthesis and spectroscopic, solid state and theoretical characterization
Authors: Halder Nyancy , Sangeetha Mohandas , Usharani Dandamudi , Rath Harapriya
Published: May 2019

meso-Aryl substituted highly stable single conformers of doubly mutant porphodimethenes.
Degradable poly(ethylene oxide) through metal-free copolymerization of ethylene oxide with l-lactide
Authors: Varghese Jobi Kodiyan , Hadjichristidis Nikos , Gnanou Yves , Feng Xiaoshuang
Published: May 2019

A simple and convenient method for the preparation of degradable poly(ethylene oxide) (PEO) is presented in this work.
Mechanical chiral resolution
Authors: Marichez Vincent , Tassoni Alessandra , Cameron Robert P. , Barnett Stephen M. , Eichhorn Ralf , Genet Cyriaque , Hermans Thomas M.
Published: May 2019

In this review, we show that these interactions are of importance even at the nanoscale. Mechanical chiral resolution is promising in the field of soft matter and for industry.
Rivalry inBacillus subtiliscolonies: enemy or family?
Authors: Paul Rajorshi , Ghosh Tanushree , Tang Tian , Kumar Aloke
Published: May 2019

SiblingBacillus subtiliscolonies interact by demarcation (enemy) or merging (family), the regimes being separated by the Laxman Line.
Cholesterol efflux capacity assay using immobilized liposomes and apolipoprotein B-depleted serum
Authors: Sapa Hima Rani
Published: May 2019

Cholesterol efflux capacity (CEC), an important functional step in reverse cholesterol transport, is the main anti-atherosclerotic function of high-density lipoprotein (HDL). Assays that improve the determination of CEC ex vivo for clinical applications are constantly explored. In the accompanying article, Horiuchi et al. (Biosci. Rep. (2019) 39(4), BSR20190213) evaluate the availability of apolipoprotein B-depleted serum for CEC assays. Using their recently developed immobilized liposome-bound gel beads (ILG) method, Horiuchi et al. demonstrate that apolipoprotein B-depleted serum obtained with poly ethylene glycol precipitation enables CEC assays to be easily and accurately introduced into laboratory medicine.
Blind recognition of alpha‐stable random carrier signals by an eavesdropper in random communication systems
Authors: Ahmed Areeb , Savaci Ferit Acar
Published: May 2019

Invisibility of alpha‐stable (α‐stable) noise as carrier signals, in the presence of additive white Gaussian noise (AWGN) as channel noise, is a key factor to ensure covert transmission by employing random communication systems (RCSs). This study introduces a novel blind recognition method for an eavesdropper to detect the presence of real‐valued symmetric and skewed α‐stable random carrier signals in the presence of AWGN. The introduced method is based on the proposed random carrier signal recogniser (RCSR), which consists of fractional lower‐order auto‐covariance block, threshold control block and the random carrier signal recognition indicator. The proposed RCSR first detects the possible presence of α‐stable random carrier signals and then recognises the impulsiveness and skewness parameters, exploited by the transmitter and the intended receiver, to extract covertly conveyed binary information. However, the determined covert range can be adopted to perform secure transmission by RCSs. The simulation results reflect the simplicity of the proposed method as it is capable of performing effectively in real time by utilising extremely less number of observed samples.
Cooperative scheduling of multi‐core and cloud resources: multi‐thread‐based MCC offloading strategy
Authors: Wang Zhaoyang , Han Zhuo , Yan Lei , Yang Shouyi
Published: May 2019

Modern multi‐core mobile devices are the main application objects of mobile cloud computing (MCC). In previous works, researchers have formulated various heuristic algorithms to solve the NP problem. This work combines MCC with multi‐threaded computing (MTC) of multi‐core mobile devices to avoid NP problems and proposes an MTC‐based MCC offloading strategy. First, the authors design an MTC strategy for the application model of cloud computing. Then, they use the data transmission scheme that is dynamically adjusted according to the fading channel state. Finally, based on the MTC strategy and the optimal data transmission scheme, they obtain the MTC‐based MCC offloading strategy through a linear time searching algorithm. Simulation results show that compared with the local MTC strategy and the single‐threaded MCC offloading strategy, the MTC‐based MCC offloading strategy can significantly reduce energy consumption and improve the computing ability in multi‐threaded applications.
Image unmosaicing without location information using stacked GAN
Authors: Javed Kamran , Ud Din Nizam , Bae Seho , Yi Juneho
Published: May 2019

Image mosaicing is an image processing technique that is most commonly used to conceal identities of sensitive objects. The authors’ research features recovering the mosaiced parts in an image, especially focusing on facial parts. While recent image completion methods based on deep learning have shown promising results on recovering damaged parts in an image, they have not addressed the problem of image unmosaicing. Moreover, all those methods necessitate the location information of damaged parts to tackle the recovery problem. They formulate unmosaicing as an image‐to‐image translation problem, and propose a two‐stage method using generative adversarial network (GAN): stage‐I GAN generates a coarse prediction followed by stage‐II GAN which produces a final unmosaiced image with finer information. A combination of low‐level loss and high‐level structural similarity loss is used to attain visually plausible and semantically consistent output. They have evaluated their method on the CelebA dataset and achieved better results than state‐of‐the‐art image completion methods without explicitly exploiting the location information of mosaiced parts.
Stabilisation and transient performance improvement of DC MGs with CPLs: non‐linear reset control approach
Authors: Vafamand Navid , Khayatian Alireza , Khooban Mohammad Hassan
Published: May 2019

The stabilisation and transient performance improvement of a non‐linear direct current (DC) microgrid (MG) dynamic which is controlled by a power buffer is studied. The injecting current of the power buffer is designed based on a novel reset gain‐scheduling controller. This controller is constructed via a polytopic linear parameter varying‐based dynamic controller that is equipped with the resetting action. The dynamic controller theoretically assures the closed‐loop stability of the DC MG through the continuous‐time Lyapunov theory. Also, the resetting action enhances the transient performance. The sufficient conditions of the controller design are derived in terms of linear matrix inequality and are solved by convex numerical methods. Comparing with the existing results, the proposed hybrid approach provides a non‐continuous current reference of the power buffer, which efficiently improves the transient performance. To show the merits of the proposed approach, it is applied to a non‐linear DC MG feeding one constant power load (CPL). Results show the simplicity of designing the proposed controller and the settling time and overshoot of the DC bus voltage compared to the state‐of‐the‐art methods. Also, software‐in‐the‐loop simulations are presented to prove the practical applicability of the proposed controller.
Impact of grounding fault in PV modules on AC side and the suppression strategy based on 0‐axis control
Authors: Zhang Yong , Xia Yanghong , Lv Zeyan , Yu Miao , Wei Wei
Published: May 2019

The widely distributed large‐scale photovoltaic (PV) modules suffer from a large probability of grounding fault due to their own characteristics and natural weather. This problem has been well explored in this study. Firstly, it is analysed that the grounding fault in PV modules will cause the third‐harmonic voltage, DC bias voltage and common ground circulating current in the PV inverter system. Secondly, a 0‐axis based control strategy is proposed to solve the above problems, which means that the zero‐sequence voltage is controlled through a proportional‐resonant controller in the outer loop, and the zero‐sequence current is controlled in the inner loop through a proportional controller. Thirdly, the square of DC side voltage is controlled to address the non‐linear relationship between capacitor energy and its voltage. Finally, the experimental results based on RTLAB platform are presented to verify the effectiveness of the proposed control strategy. In summary, this study proposes a control thought to suppress the undesirable phenomenon caused by the grounding fault in PV modules, and the method needs no status switching and hardware cost.
Robust expansion co‐planning of electricity and natural gas infrastructures for multi energy‐hub systems with high penetration of renewable energy sources
Authors: Karamdel Shahab , Moghaddam Mohsen Parsa
Published: May 2019

High penetration of renewable energy sources will cause crucial challenges for future energy systems. This study presents a three‐level model for adaptive robust expansion co‐planning of electricity and natural gas infrastructures in multi‐energy‐hub networks, which is robust against uncertainties of maximum production of wind generation and gas‐fired power plants as well as estimated load levels. The proposed min–max–min model is formulated as a mixed integer linear programming problem. The first level minimises the investment cost of electricity and natural gas infrastructures, the worst possible case is determined through the second level, and the third level minimises the overall operation cost under that condition. To solve this model, the final minimisation problem is replaced by its Karush–Kuhn–Tucker conditions and a two‐level problem is determined. Finally, by using the column and constraint generation algorithm the original problem is decomposed to master and sub‐problems and the optimal solution is derived iteratively. The proposed robust expansion co‐planning model is tested on modified Garver's 6‐hub, modified IEEE RTS 24‐hub, and modified IEEE 118‐hub test systems and numerical results show its effectiveness to cope with uncertainties with regard to control conservativeness of the plan.
Accurate phasor and frequency estimation during power system oscillations using least squares
Authors: Koteswara Rao Ayyalasomayajula Venkata , Soni Krishan Mohan , Sinha Sanjay Kumar , Nasiruddin Ibraheem
Published: May 2019

Accurate estimation of a phasor, frequency, and rate of change of frequency during changing power system condition is important to initiate precise control action for reliable power system operation. Conventional phasor estimation techniques cannot estimate the phasor accurately during dynamic conditions of power system. Furthermore, the phasor‐based frequency estimation algorithms are being affected under such conditions. In this study, both angle and amplitude modulation parameters are considered in the signal model to improve the accuracy of the phasor estimation. The method uses Taylor's series expansion to linearise the signal model and computes the signal parameters using least squares. The method first computes the phasor using estimated parameters of the signals, subsequently calculates the frequency and rate of change of frequency. The performance of the proposed method is evaluated for standard test signals. Real signals recorded in numerical relay are used to assess the performance of the proposed method. The results are compared with the available method and found that the method can supplement the existing methods used in phasor measurement units and intelligent electronic devices.
Revisiting the pulsational characteristics of the exoplanet host starβPictoris
Authors: Zwintz K. , Reese D. R. , Neiner C. , Pigulski A. , Kuschnig R. , Müllner M. , Zieba S. , Abe L. , Guillot T. , Handler G. , Kenworthy M. , Stuik R. , Moffat A. F. J. , Popowicz A. , Rucinski S. M. , Wade G. A. , Weiss W. W. , Bailey J. I. , Crawford S. , Ireland M. , Lomberg B. , Mamajek E. E. , Mellon S. N. , Talens G. J.
Published: May 2019

Context.Exoplanet properties crucially depend on the parameters of their host stars: more accurate stellar parameters yield more accurate exoplanet characteristics. When the exoplanet host star shows pulsations, asteroseismology can be used for an improved description of the stellar parameters.

Aims.We aim to revisit the pulsational properties ofβPic and identify its pulsation modes from normalized amplitudes in five different passbands. We also investigate the potential presence of a magnetic field.

Methods.We conducted a frequency analysis using three seasons of BRITE-Constellation observations in the two BRITE filters, the about 620-day-long bRing light curve, and the nearly 8-year-long SMEI photometric time series. We calculated normalized amplitudes using all passbands and including previously published values obtained from ASTEP observations. We investigated the magnetic properties ofβPic using spectropolarimetric observations conducted with the HARPSpol instrument. Using 2D rotating models, we fit the normalized amplitudes and frequencies through Monte Carlo Markov chains.

Results.We identify 15 pulsation frequencies in the range from 34 to 55 d−1, where two, F13 at 53.6917 d−1and F11 at 50.4921 d−1, display clear amplitude variability. We use the normalized amplitudes in up to five passbands to identify the modes as three ℓ = 1, six ℓ = 2, and six ℓ = 3 modes.βPic is shown to be non-magnetic with an upper limit of the possible undetected dipolar field of 300 Gauss.

Conclusions.Multiple fits to the frequencies and normalized amplitudes are obtained, including one with a near equator-on inclination forβPic, which corresponds to our expectations based on the orbital inclination ofβPic b and the orientation of the circumstellar disk. This solution leads to a rotation rate of 27% of the Keplerian breakup velocity, a radius of 1.497 ± 0.025R⊙, and a mass of 1.797 ± 0.035M⊙. The ∼2% errors in radius and mass do not account for uncertainties in the models and a potentially erroneous mode-identification.
Sind Low-Carb-Diäten lebensgefährlich?
Authors: Worm Nicolai , Lechner Katharina
Published: May 2019

Die kürzlich veröffentlichte ARIC-Studie wie auch eine Reihe weiterer zuvor veröffentlichter Langzeitbeobachtungsstudien (Kohortenstudien), haben ein erhöhtes Sterblichkeitsrisiko für Studienteilnehmer mit „niedrigerem“ Kohlenhydratanteil aufgezeigt. Bekanntlich können epidemiologische Erhebungen prinzipiell keine Kausalität belegen, sondern nur Assoziationen aufzeigen. Außerdem leiden epidemiologische Erhebungen in der Ernährungsmedizin oft unter fehleranfälligen Erhebungsmethoden, wie auch unter konfundierenden, nicht oder nicht adäquat berücksichtigten Lebensstil- und Umwelteinflüssen (Healthy User Bias).

Obwohl die ARIC-Studie keine Diät und insbesondere keine Low-Carb-Diät experimentell überprüft hatte, und trotz der bekannten Problematik epidemiologischer Studien, sorgten Schlagzeilen wie „Low-Carb-Diäten sind lebensgefährlich“ weltweit für Verunsicherung bei Verbrauchern, bei denen sich solche Diäten zur Gewichtskontrolle wie auch zur Therapie von Stoffwechselstörungen einer immer größeren Beliebtheit erfreuen. Die Ergebnisse dieser epidemiologischen Studien stehen auch im Widerspruch zu den inzwischen in randomisiert-kontrollierten Interventionsstudien gut belegten günstigen metabolischen Effekten von Low-Carb-Diäten – insbesondere unter einer mediterran ausgerichteten kohlenhydratreduzierten Ernährung. Vor diesem Hintergrund finden Low-Carb-Diäten neuerdings auch Anerkennung in Fachkreisen und Eingang in Leitlinien. Ziel des vorliegenden Viewpoints ist es, anhand der aktuellen Publikation zur ARIC-Studie mit den dort postulierten Einflüssen der Ernährung auf die Sterblichkeit zu diskutieren, wie problematisch es ist, auf Basis unzureichend kontrollierbarer epidemiologischer Daten auf kausale Zusammenhänge zu schließen. Gleichzeitig soll die auf die Veröffentlichung der ARIC-Studie gefolgte mediale Berichterstattung mit ihren eindeutigen Schlussfolgerungen zur angeblichen Gefährlichkeit von „Low-Carb-Diäten“ der Evidenz gegenübergestellt werden.
Diäterfahrungen zur Gewichtsreduzierung von Jugendlichen in Deutschland – Ergebnisse aus EsKiMo II
Authors: Lehmann Franziska , Barbosa Clarissa Lage , Haftenberger Marjolein , Brettschneider Anna-Kristin , Frank Melanie , Patelakis Eleni , Heide Karoline , Perlitz Hanna , Hölling Heike , Richter Almut , Mensink Gert B. M.
Published: May 2019

Das gesellschaftlich vorherrschende Schönheitsideal löst häufig einen starken Schlankheitsdruck aus. Dies kann vor allem bei Jugendlichen zu Unzufriedenheit mit dem eigenen Körper führen und den Wunsch nach Gewichtsreduzierung hervorrufen. Aktuelle und repräsentative Daten zu den Diäterfahrungen, der in Deutschland lebenden 12- bis 17-Jährigen, liefert die „Ernährungsstudie als KiGGS-Modul – EsKiMo II“ (2015 – 2017). Die Auswertungen zeigen, dass rund 17 % der Jugendlichen in den letzten 3 Jahren mindestens eine Diät zur Gewichtsreduzierung durchgeführt haben, wobei dies für Mädchen signifikant häufiger gilt als für Jungen. Von den Jugendlichen mit Übergewicht und Adipositas haben 40 % bereits Diäterfahrung. Der Median der Dauer einer durchschnittlichen Diät beträgt 30 Tage. Die Ergebnisse aus EsKiMo II zeigen eine beträchtliche Prävalenz an Diäterfahrung unter Jugendlichen. Damit besteht ein erheblicher Bedarf an geeigneten Angeboten zur Gewichtsreduzierung bei Übergewicht und Adipositas.
Chemical diversity in molecular orbital energy predictions with kernel ridge regression
Authors: Stuke Annika , Todorović Milica , Rupp Matthias , Kunkel Christian , Ghosh Kunal , Himanen Lauri , Rinke Patrick
Published: May 2019

Instant machine learning predictions of molecular properties are desirable for materials design, but the predictive power of the methodology is mainly tested on well-known benchmark datasets. Here, we investigate the performance of machine learning with kernel ridge regression (KRR) for the prediction of molecular orbital energies on three large datasets: the standard QM9 small organic molecules set, amino acid and dipeptide conformers, and organic crystal-forming molecules extracted from the Cambridge Structural Database. We focus on the prediction of highest occupied molecular orbital (HOMO) energies, computed at the density-functional level of theory. Two different representations that encode the molecular structure are compared: the Coulomb matrix (CM) and the many-body tensor representation (MBTR). We find that KRR performance depends significantly on the chemistry of the underlying dataset and that the MBTR is superior to the CM, predicting HOMO energies with a mean absolute error as low as 0.09 eV. To demonstrate the power of our machine learning method, we apply our model to structures of 10k previously unseen molecules. We gain instant energy predictions that allow us to identify interesting molecules for future applications.
Resilience evaluation for UAV swarm performing joint reconnaissance mission
Authors: Cheng Congcong , Bai Guanghan , Zhang Yun-An , Tao Junyong
Published: May 2019

The resilience of unmanned aerial vehicle (UAV) swarm is its joint capability to resist possible threat, adapt to disruptive events, and restore its intended performance under a specific time period. The quantitative assessment of the UAV swarm resilience requires a thorough understanding of its missions. In this paper, a mission-oriented framework is proposed to implement the resilience evaluation for the UAV swarm. Guided by the framework, the resilience evaluation for the UAV swarm performing joint reconnaissance mission is studied. A UAV swarm model is developed for joint reconnaissance mission based on complex networks and agent-based models. The following aspects of the UAV swarm are considered in the proposed model, namely, the mission orientation, UAV attributes, swarm topology, UAV cooperative strategy, UAV information exchange and fusion strategy, potential threats, recovery strategies, etc. Then, a novel performance metric is proposed to measure the mission capability of the UAV swarm performing joint reconnaissance mission. Results from the simulations show that, compared with existing studies, the proposed approach can provide more realistic and objective resilience evaluation for the mission-oriented UAV swarm. The above works can be used to support the decision making and the optimal design of the UAV swarm, given different missions.
Unraveling mechanisms from waiting time distributions in single-nanoparticle catalysis
Authors: Panigrahy Manmath , Kumar Ashutosh , Chowdhury Sutirtha , Dua Arti
Published: May 2019

The catalytic conversion of substrates to products at the surface of a single nanoparticle cluster can now be resolved at the molecular scale and the waiting time between individual product turnovers measured with precision. The distribution of waiting times and, in particular, their means and variances can thus be obtained experimentally. Here, we show how theoretical modeling based on the chemical master equation (CME) provides a powerful tool to extract catalytic mechanisms and rate parameters from such experimental data. Conjecturing a family of mechanisms that both include and exclude surface restructuring, we obtain the mean and variance of their waiting times from the CME. A detailed analysis of the link between mechanism topology and waiting time dispersion, then, allows us to select several candidate mechanisms, with branched topologies, that can reproduce experimental data. From these, the least complex model that best matches experimental data is chosen as the minimum model. The CME modeling extracts the Langmuir-Hinshelwood mechanism for product formation and two-pathway mechanism for product dissociation, with substantial off-pathway state fluctuations due to surface restructuring dynamics, as the minimal model consistent with data. Our work, thus, provides a mechanistic origin of the coupling between the kinetics of catalytic turnovers and surface restructuring dynamics and yields a systematic way to compute catalytic rates from distributions of waiting times between product turnovers in the presence of surface restructuring.
Elucidating the nature of crystallization kinetics in Zr46Cu46Al8 metallic glass through simultaneous WAXS/SAXS measurements
Authors: Wu Xuelian , Lan Si , Wei Xiaoya , Zhou Jie , Lu Zhaoping , Almer Jonathan D. , Wang Xun-Li
Published: May 2019

Simultaneous wide- and small-angle X-ray scattering (WAXS/SAXS) measurements were performed to investigate the low-temperature crystallization kinetics of Zr46Cu46Al8 bulk metallic glass during isothermal annealing. Quantitative analysis of the WAXS intensity data indicated that the crystallization process was dominated by steady-state homogeneous nucleation and three-dimensional diffusion-controlled growth. This observation was corroborated by quantitative analysis of the SAXS data showing a saturation of the growth of nanoscale crystallites. Comparison of simultaneously measured WAXS and SAXS data showed evidence of composition fluctuation prior to crystallization, suggesting that the crystallization was facilitated by nanoscale phase separation which established regions of favorable compositions catalyzing crystallization. The temperature dependence of crystallization mechanisms and the resulting microstructures in metallic glass are discussed.
Repulsive synchronization in complex networks
Authors: Gao Ya-Chun , Fu Chuan-Ji , Cai Shi-Min , Yang Chun , Eugene Stanley H.
Published: May 2019

Synchronization in complex networks characterizes what happens when an ensemble of oscillators in a complex autonomous system become phase-locked. We study the Kuramoto model with a tunable phase-lag parameter α in the coupling term to determine how phase shifts influence the synchronization transition. The simulation results show that the phase frustration parameter leads to desynchronization. We find two global synchronization regions for α∈[0,2π) when the coupling is sufficiently large and detect a relatively rare network synchronization pattern in the frustration parameter near α=π. We call this frequency-locking configuration as “repulsive synchronization,” because it is induced by repulsive coupling. Since the repulsive synchronization cannot be described by the usual order parameter r, the parameter frequency dispersion is introduced to detect synchronization.
From nonlinear reaction-diffusion processes to permanent microscale structures
Authors: Malchow Anne-Kathleen , Azhand Arash , Knoll Pamela , Engel Harald , Steinbock Oliver
Published: May 2019

Biomorphs are polycrystalline aggregates that self-assemble during inorganic precipitation reactions. The shape repertoire of these microstructures include hemispherical objects with complicated internal features such as radial spikes and cones as well as folded sheets reminiscent of corals. We propose that at the microscale, some of these patterns are caused by nonlinear reaction-diffusion processes and present a simple model for this unconventional type of precipitation. The model consists of three reaction steps that convert a reactant species autocatalytically into an intermediate and eventually into a solid, immobile product. Numerical simulations of the model in three space dimensions reveal product structures that are similar to the experimentally observed biomorphs.
The influence of interaction between oxygen vacancies on set process in resistive switching: A case of MgO
Authors: Guo Yanrui , Song Qinggong , Yan Huiyu
Published: May 2019

The influence factor of filaments consisted of oxygen vacancies (VOs) is important for resistive switching. In this paper, the interaction between VOs in MgO and its influence on VO-filaments are studied using density functional theory. It reveals that the VOs in MgO tend to be aggregation state. The distribution of energy level for VO pair in band gap changes with different configurations. The interaction between VO chains also results in their aggregation state in MgO insulator. The calculation results show that with the diameter of filament increasing, the formation energy per VO decreases and the filaments presents semiconductor-metal transition. Based on these calculation results, the set process of MgO based resistive switching is discussed.
Ehrenfest and classical path dynamics with decoherence and detailed balance
Authors: Nijjar Parmeet , Jankowska Joanna , Prezhdo Oleg V.
Published: May 2019

We present a semiclassical approach for nonadiabatic molecular dynamics based on the Ehrenfest method with corrections for decoherence and detailed balance. Decoherence is described via a coherence penalty functional that drives dynamics away from regions in Hilbert space characterized by large values of coherences. Detailed balance is incorporated by modification of the off-diagonal matrix elements with a quantum correction factor used in semiclassical approximations to quantum time-correlation functions. Both decoherence and detailed balance corrections introduce nonlinear terms to the Schrödinger equation. At the same time, the simplicity of fully deterministic dynamics and a single trajectory for each initial condition is preserved. In contrast, surface hopping is stochastic and requires averaging over multiple realization of the stochastic process for each initial condition. The Ehrenfest-decoherence-detailed-balance (Ehrenfest-DDB) method is adapted to the classical path approximation and ab initio time-dependent density functional theory and applied to an experimentally studied nanoscale system consisting of a fluorophore molecule and an scanning tunneling microscopy tip and undergoing current-induced charge injection, cooling, and recombination. Ehrenfest-DDB produces time scales that are similar to those obtained with decoherence induced surface hopping, which is a popular nonadiabatic molecular dynamics technique applied to condensed matter. At long times, Ehrenfest-DDB dynamics slows down considerably because the detailed balance correction makes off-diagonal elements go to zero on approach to Boltzmann equilibrium. The Ehrenfest-DDB technique provides efficient means to study quantum dynamics in large systems.
Maximum supercooling studies in Ti39.5Zr39.5Ni21, Ti40Zr30Ni30, and Zr80Pt20 liquids—Connecting liquid structure and the nucleation barrier
Authors: Sellers M. E. , Van Hoesen D. C. , Gangopadhyay A. K. , Kelton K. F.
Published: May 2019

Almost three quarters of a century ago, Charles Frank proposed that the deep supercooling observed in metallic liquids is due to icosahedral short-range order (ISRO), which is incompatible with the long-range order of crystal phases. Some evidence in support of this hypothesis had been published previously. However, those studies were based on a small population of maximum supercooling measurements before the onset of crystallization. Here, the results of a systematic statistical study of several hundred maximum supercooling measurements on Ti39.5Zr39.5Ni21, Ti40Zr30Ni30, and Zr80Pt20 liquids are presented. Previous X-Ray and neutron scattering studies have shown that the structures of these liquid alloys contain significant amounts of ISRO. The results presented here show a small work of critical cluster formation (W* = 31–40 kBT) from the analysis of the supercooling data for the Ti39.5Zr39.5Ni21 liquid, which crystallizes to a metastable icosahedral quasicrystal. A much larger value (W* = 54–79 kBT and W* = 60–99 kBT) was obtained for the Ti40Zr30Ni30 and Zr80Pt20 liquids, respectively, which do not crystallize to an icosahedral quasicrystal. Taken together, these results significantly strengthen the validity of Frank’s hypothesis.
Structural degeneracy in pair distance distributions
Authors: Stillinger Frank H. , Torquato Salvatore
Published: May 2019

A traditional basic descriptor of many-particle systems has been the distribution of interparticle pair distances. In the case of structureless particles at thermal equilibrium, with just additive pair interactions, this suffices to determine pressure and mean energy. However, it is usually the case that a given set of pair distances can emerge from a multiplicity of distinguishable many-particle configurations. This paper focuses on the ways in which such a configuration detail can be overlooked. After providing some elementary small-system examples in which full pair distance specification still permits distinct configurational pattern ambiguity, subsequent analysis concentrates on large-system classical canonical ensembles. In that context, configurational degeneracy is analyzed in two-dimensional systems for the shape distribution of triangles, whose chirality occurrence can be controlled by suitable three-particle interactions. For many-particle systems in three dimensions, the possibility is explored that a set of three-particle “pair-invisible” interactions can exist which modify the three-particle distribution function, but which have no effect on the pair distribution function, and thus remain undetected by conventional diffraction experiments. For illustration, a specific mathematical example is presented, applicable to the case where two-particle interactions vanish.
Solvent effects on acid-base complexes. What is more important: A macroscopic reaction field or solute-solvent interactions?
Authors: Shenderovich Ilya G. , Denisov Gleb S.
Published: May 2019

Can the geometry of an acid-base complex in solution be reproduced in calculations using an implicit accounting for the solvent effect in the form of a macroscopic reaction field? The answer is, “Yes, it can.” Is this field equal to the real electric field experienced by the complex in solution? The answer is, “No, it is not.” How can the geometry be correct under wrong conditions? This question is answered using density functional theory modeling of geometric and NMR parameters of pyridine⋯HF⋯(HCF3)n adducts in the absence and presence of an external electric field. This adduct under field approach shows that the N⋯H distance is a function of the H–F distance whatever method is used to change the geometry of the latter. An explicit account for solute-solvent interactions is required to get a realistic value of the solvent reaction field. Besides that, this approach reveals how certain NMR parameters depend on the solvent reaction field, the solute-solvent interactions, and the geometry of the N⋯H–F hydrogen bond. For some of them, the obtained dependences are far from self-evident.
Influence of long-range interactions on quantum interference in molecular conduction. A tight-binding (Hückel) approach
Authors: Tsuji Yuta , Estrada Ernesto
Published: May 2019

When certain pairs of atoms in a π-conjugated molecule are connected with nanometer-scale source and drain electrodes, the remarkable quantum interference (QI) effect may arise. In this case, the electron transmission probability is significantly suppressed due to the QI effect. Tight-binding approaches, such as the Hückel molecular orbital (HMO) model, have revealed important features of this quantum phenomenon. However, important deviations from experiments and from more sophisticated calculations are known for a variety of cases. Here, we propose an extension of the HMO method to include non-nearest-neighbor interactions. Such long-range interactions (LRIs) are implemented in the HMO model in the form of a damping function that decays as the topological distance—the number of bonds separating two atoms—gets larger. The proposed model is further developed so that a geometric modification, i.e., the rotation around a single bond, can be taken into account. Our results show that LRI affects both the location of the antiresonance peak due to QI and the intensity of QI, even suppressing it in some cases. These results agree well with what was observed in a Density Functional based Tight-Binding (DFTB) study reported in the literature. These properties can be interpreted on the basis of a graph-theoretic path-counting model as well as the molecular orbital theory. In addition, the geometric LRI model is shown to reproduce the change of transmission as a function of rotation around the single bond separating two benzene rings in biphenyl, in agreement with what was observed in both experiment and DFTB calculation.
Homogeneous ice nucleation rates and crystallization kinetics in transiently-heated, supercooled water films from 188 K to 230 K
Authors: Kimmel Greg A. , Xu Yuntao , Brumberg Alexandra , Petrik Nikolay G. , Smith R. Scott , Kay Bruce D.
Published: May 2019

The crystallization kinetics of transiently heated, nanoscale water films were investigated for 188 K < Tpulse < 230 K, where Tpulse is the maximum temperature obtained during a heat pulse. The water films, which had thicknesses ranging from approximately 15–30 nm, were adsorbed on a Pt(111) single crystal and heated with ∼10 ns laser pulses, which produced heating and cooling rates of ∼109–1010 K/s in the adsorbed water films. Because the ice growth rates have been measured independently, the ice nucleation rates could be determined by modeling the observed crystallization kinetics. The experiments show that the nucleation rate goes through a maximum at T = 216 K ± 4 K, and the rate at the maximum is 1029±1 m−3 s−1. The maximum nucleation rate reported here for flat, thin water films is consistent with recent measurements of the nucleation rate in nanometer-sized water drops at comparable temperatures. However, the nucleation rate drops rapidly at lower temperatures, which is different from the nearly temperature-independent rates observed for the nanometer-sized drops. At T ∼ 189 K, the nucleation rate for the current experiments is a factor of ∼104−5 smaller than the rate at the maximum. The nucleation rate also decreases for Tpulse > 220 K, but the transiently heated water films are not very sensitive to the smaller nucleation rates at higher temperatures. The crystallization kinetics are consistent with a “classical” nucleation and growth mechanism indicating that there is an energetic barrier for deeply supercooled water to convert to ice.
Molecular oxygen generation from the reaction of water cations with oxygen atoms
Authors: Fortenberry Ryan C. , Trabelsi Tarek , Westbrook Brent R. , Del Rio Weston A. , Francisco Joseph S.
Published: May 2019

The oxywater cation (H2OO+), previously shown to form barrierlessly in the gas phase from water cations and atomic oxygen, is proposed here potentially to possess a 2A″ ←4A″ excitation leading to the H2⋯O2+ complex. This complex could then easily decompose into molecular hydrogen and the molecular oxygen cation. The present quantum chemical study shows that the necessary electronic transition takes place in the range of 1.92 eV (645 nm), in the orange-red range of the visible and solar spectrum, and dissociation of the complex only requires 5.8 kcal/mol (0.25 eV). Such a process for the abiotic, gas phase formation of O2 would only need to be photocatalyzed by visible wavelength photons. Hence, such a process could produce O2 at the mesosphere/stratosphere boundary as climate change is driving more water into the upper atmosphere, in the comet 67P/Churyumov-Gerasimenko where surprisingly high levels of O2 have been observed, or at gas-surface (ice) interfaces.
Revised taxonomic status of Pseudalmenus barringtonensis Waterhouse, 1928 stat. rev. (Lepidoptera: Lycaenidae): uncovering Australia’s greatest taxonomic fraud
Authors: Braby Michael F. , Eastwood Rod
Published: May 2019

The Australian endemic lycaenid Pseudalmenus H.H. Druce, 1902 occupies a unique phylogenetic position within the Theclinae–Polyommatinae assemblage. Although the genus exhibits complex geographic variation, it has long been considered to be monotypic. However, evidence from adult phenotype (colour pattern), immature stages (final instar larva) and ecology (ant specificity) (total of 10 unique character states) as well as limited genetic data (mitochondrial COI) suggest that there are two species, namely, P. chlorinda (Blanchard, 1848) from Tasmania and the mainland of south-eastern Australia and P. barringtonensis Waterhouse, 1928 stat. rev., which is allopatric and narrowly restricted to montane areas in northern New South Wales. Examination of the ‘holotype’ male of P. barringtonensis in the Australian Museum showed that it is a fake, although the data label is genuine; the specimen is actually P. chlorinda chloris Waterhouse & Lyell, 1914 that has been modified with red paint to resemble P. barringtonensis. The true holotype is currently missing, but a specimen in the Australian Museum (registration No. K199026) that is part of the Colin W. Wyatt Theft Collection with a fictitious label is almost certainly the true holotype of P. barringtonensis. We discuss the history of this most unusual and bizarre circumstance and conclude that Wyatt stole the holotype sometime in 1946 before he returned to England (~72 years ago) and fabricated the fake holotype as a replacement specimen. Such a fraudulent and unprecedented act surely ranks as Australia’s greatest taxonomic fraud.
New records of Lindernia s.l. (Linderniaceae) for eastern Australia
Authors: Wannan Bruce S.
Published: May 2019

One new species of Lindernia All. is described (L. yarun Wannan) from south-eastern Queensland. The following three species of Lindernia are newly recognised for Queensland: L. clausa (F.Muell.) F.Muell., L. procumbens (Krock.) Philcox and L. rotundifolia (L.) Alston. Illustrations of flowers, fruits, seeds, leaves, stem anatomy, and specimens are provided. Notes on habitat, distribution and conservation status are also provided. A key to eastern Australian species of Lindernia, Bonnaya Link & Otto and Yamazakia W.R.Barker, Y.S.Liang & Wannan is provided.
JAK/STAT inhibition in macrophages promotes therapeutic resistance by inducing expression of protumorigenic factors
Authors: Irey Emily A. , Lassiter Chelsea M. , Brady Nicholas J. , Chuntova Pavlina , Wang Ying , Knutson Todd P. , Henzler Christine , Chaffee Thomas S. , Vogel Rachel I. , Nelson Andrew C. , Farrar Michael A. , Schwertfeger Kathryn L.
Published: May 2019

Tumor-associated macrophages contribute to tumor progression and therapeutic resistance in breast cancer. Within the tumor microenvironment, tumor-derived factors activate pathways that modulate macrophage function. Using in vitro and in vivo models, we find that tumor-derived factors induce activation of the Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) pathway in macrophages. We also demonstrate that loss of STAT3 in myeloid cells leads to enhanced mammary tumorigenesis. Further studies show that macrophages contribute to resistance of mammary tumors to the JAK/STAT inhibitor ruxolitinib in vivo and that ruxolitinib-treated macrophages produce soluble factors that promote resistance of tumor cells to JAK inhibition in vitro. Finally, we demonstrate that STAT3 deletion and JAK/STAT inhibition in macrophages increases expression of the protumorigenic factor cyclooxygenase-2 (COX-2), and that COX-2 inhibition enhances responsiveness of tumors to ruxolitinib. These findings define a mechanism through which macrophages promote therapeutic resistance and highlight the importance of understanding the impact of targeted therapies on the tumor microenvironment.
Hypoxia induces the dormant state in oocytes through expression of
Foxo3
Authors: Shimamoto So , Nishimura Yohei , Nagamatsu Go , Hamada Norio , Kita Haruka , Hikabe Orie , Hamazaki Nobuhiko , Hayashi Katsuhiko
Published: May 2019

In mammals, most immature oocytes remain dormant in the primordial follicles to ensure the longevity of female reproductive life. A precise understanding of mechanisms underlying the dormancy is important for reproductive biology and medicine. In this study, by comparing mouse oogenesis in vivo and in vitro, the latter of which bypasses the primordial follicle stage, we defined the gene-expression profile representing the dormant state of oocytes. Overexpression of constitutively active FOXO3 partially reproduced the dormant state in vitro. Based on further gene-expression analysis, we found that a hypoxic condition efficiently induced the dormant state in vitro. The effect of hypoxia was severely diminished by disruption of the
Foxo3
gene and inhibition of hypoxia-inducible factors. Our findings provide insights into the importance of environmental conditions and their effectors for establishing the dormant state.
Routing information flow by separate neural synchrony frequencies allows for “functionally labeled lines” in higher primate cortex
Authors: Khamechian Mohammad Bagher , Kozyrev Vladislav , Treue Stefan , Esghaei Moein , Daliri Mohammad Reza
Published: May 2019

Significance

Dynamical coordination of the neural activity between individual neurons is known to have a key role in the efficient transfer of sensory information to associative areas. Here, we report a role of interneuronal synchrony within the high-gamma (180 to 220 Hz) frequency range of activity in macaque area MT (a visual area in the dorsal visual pathway) in determining behavioral performance. This is, however, in contrast to previous reports for the ventral visual pathway (such as area V4), where only gamma range (40 to 70 Hz) was observed to play a role. We propose that such a difference between the functional coordination in different visual pathways might be used to unambiguously identify the source of input to the higher areas.
ANO1/TMEM16A regulates process maturation in radial glial cells in the developing brain
Authors: Hong Gyu-Sang , Lee Sung Hoon , Lee Byeongjun , Choi Jae Hyouk , Oh Soo-Jin , Jang Yongwoo , Hwang Eun Mi , Kim Hyungsup , Jung Jooyoung , Kim In-Beom , Oh Uhtaek
Published: May 2019

Significance

Radial glial cells (RGCs), a type of neural stem cell in the developing brain, not only generate progenitors, newly born neurons and glial cells, but also deliver neurons through its process to the appropriate cortical target layers. Thus, the function of RGCs is crucial for cortex development, in which Cl−channels are thought to play a role. Here we highlight that Anoctamin 1 (ANO1)/TMEM16A, a Ca2+-activated Cl−channel, mediates the process extension in RGCs. ANO1-null mice show a decrease in cortical thickness with disorganized cortical layers. Thus, as a Cl−channel, ANO1 is involved in the process maturation of RGCs and contributes to cortex development.
Building bridges to move recombination complexes
Authors: Dubois Emeline , De Muyt Arnaud , Soyer Jessica L. , Budin Karine , Legras Mathieu , Piolot Tristan , Debuchy Robert , Kleckner Nancy , Zickler Denise , Espagne Eric
Published: May 2019

Significance

The central feature of meiosis is pairing and recombination of homologous maternal and paternal chromosomes (homologs). Homolog axes become first coaligned at a certain distance; they then synapse by synaptonemal complex (SC) formation. We show that the structural and molecular pathway by which chromosomes transit from coalignment to the SC state in the fungus
Sordaria macrospora
involves the formation of robust interaxis bridges comprising axis component Spo76/Pds5, recombination proteins, and the evolutionary-conserved Zip2-Zip4 complex. Zip2-Zip4 mediates the recombination complex/structure interface from coalignment onward. These findings solve the conundrum of how recombination complexes move from on-axis localization at coalignment to between-axis localization on SC central regions and provoke new ideas about the molecular and mechanistic nature of SC nucleation.