bluuebunny/crossref_metadata_2025 huggingface dataset:
Unique Solid Phase Microextraction Sampler Reveals Distinctive Biogeochemical Profiles among Various Deep-Sea Hydrothermal Vents
Authors: Grandy Jonathan James , Onat Bora , Tunnicliffe Verena , Butterfield David A. , Pawliszyn Janusz
Published: January 2020

Current methods for biochemical and biogeochemical analysis of the deep-sea hydrothermal vent ecosystems rely on water sample recovery, or in situ analysis using underwater instruments with limited range of analyte detection and limited sensitivity. Even in cases where large quantities of sample are recovered, labile dissolved organic compounds may not be detected due to time delays between sampling and preservation. Here, we present a novel approach for in situ extraction of organic compounds from hydrothermal vent fluids through a unique solid phase microextraction (SPME) sampler. These samplers were deployed to sample effluent of vents on sulphide chimneys, located on Axial Seamount in the North-East Pacific, in the Urashima field on the southern Mariana back-arc, and at the Hafa Adai site in the central Mariana back-arc. Among the compounds that were extracted, a wide range of unique organic compounds, including labile dissolved organic sulfur compounds, were detected through high-resolution LC-MS/MS, among which were biomarkers of anammox bacteria, fungi, and lower animals. This report is the first to show that SPME can contribute to a broader understanding of deep sea ecology and biogeochemical cycles in hydrothermal vent ecosystems.
cGMP favors the interaction between APP and BACE1 by inhibiting Rab5 GTPase activity
Authors: Caudano Francesca , Montalto Giulia , Passalacqua Mario , Pronzato Maria A. , Fedele Ernesto , Ricciarelli Roberta
Published: January 2020

We previously demonstrated that cyclic guanosine monophosphate (cGMP) stimulates amyloid precursor protein (APP) and beta-secretase (BACE1) approximation in neuronal endo-lysosomal compartments, thus boosting the production of amyloid-β (Aβ) peptides and enhancing synaptic plasticity and memory. Here, we further investigated the mechanism by which cGMP regulates the subcellular localization of APP and BACE1, finding that the cyclic nucleotide inhibits the activity of Rab5, a small GTPase associated with the plasma membrane and early endosomes. Accordingly, we also found that expression of a dominant-negative Rab5 mutant increases both APP-BACE1 approximation and Aβ extracellular levels, therefore mimicking the effects induced by cGMP. These results reveal a functional correlation between the cGMP/Aβ pathway and the activity of Rab5 that may contribute to the understanding of Alzheimer’s disease pathophysiology.
VGLL3 is a prognostic biomarker and correlated with clinical pathologic features and immune infiltrates in stomach adenocarcinoma
Authors: Zhang Lihua , Li Longhai , Mao Yong , Hua Dong
Published: January 2020

Due to its poor clinical outcome, there is an urgent need to identify novel prognostic markers for stomach adenocarcinoma (STAD). Here, we aimed to explore the relationship between VGLL3 expression and clinico-pathological features, dendritic cells, macrophages, and prognosis of STAD. VGLL3 expression levels were significantly associated with histological grade, T stage, and TNM stage. VGLL3 levels and patient’s age were also independent prognostic factors of the clinical outcome of STAD. In addition, VGLL3 was associated with the abundance of macrophages and dendritic cells in tumor infiltrates, of which only VGLL3 and macrophage counts were the independent prognostic factors of immune cell infiltration in the TIMER Database. Extracellular matrix receptor interaction, focal adhesion, pathways in cancer, MAPK, JAK STAT, and WNT signaling pathways were enriched in VGLL3 high-expressing datasets as determined by Gene Set Enrichment Analysis (GSEA), while DNA replication, glyoxylate, and dicarboxylate metabolism, glutathione metabolism, homologous recombination, and glycosylphosphatidylinositol gpi banchor biosynthesis were enriched in VGLL3 low-expressing datasets. Thus, VGLL3 is a novel prognostic biomarker of both the clinical outcome and immune infiltration in STAD, and may therefore be a promising therapeutic target.
Author Correction: Weakly bound molecules as sensors of new gravitylike forces
Authors: Borkowski Mateusz , Buchachenko Alexei A. , Ciuryło Roman , Julienne Paul S. , Yamada Hirotaka , Kikuchi Yuu , Takasu Yosuke , Takahashi Yoshiro
Published: January 2020

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Coherent satellites in multispectral regenerative frequency microcombs
Authors: Yang Jinghui , Huang Shu-Wei , Xie Zhenda , Yu Mingbin , Kwong Dim-Lee , Wong Chee Wei
Published: January 2020

Multispectral frequency combs provide new architectures for laser spectroscopy, clockwork, and high-capacity communications. Frequency microcombs have demonstrated remarkable impact in frequency metrology and synthesis, albeit with spectral bandwidth bounded by intrinsic second-order dispersion and consequently low-intensities at the spectral edges. Here we report coherent satellite clusters in multispectral regenerative frequency microcombs with enhanced intensities at the octave points and engineered frequency span. Beyond the conventional bandwidth of parametric oscillation, the regenerative satellites are facilitated by higher-order dispersion control, allowing for multiphase-matched parametric processes. The satellite span is deterministically controlled from 34 to 72 THz by pumped at C/L-bands, with coherence preserved with the central comb through the nonlinear parametric process. We further show the mirrored appearance of the satellite transition dynamics simultaneously with the central comb at each comb state. These multispectral satellites extend the scope of parametric-based frequency combs and provide a unique platform for clockwork, spectroscopy and communications.
Preventing critical collapse of higher-order solitons by tailoring unconventional optical diffraction and nonlinearities
Authors: Zeng Liangwei , Zeng Jianhua
Published: January 2020

Self-trapped modes suffer critical collapse in two-dimensional cubic systems. To overcome such a collapse, linear periodic potentials or competing nonlinearities between self-focusing cubic and self-defocusing quintic nonlinear terms are often introduced. Here, we combine both schemes in the context of an unconventional and nonlinear fractional Schrödinger equation with attractive-repulsive cubic–quintic nonlinearity and an optical lattice. We report theoretical results for various two-dimensional trapped solitons, including fundamental gap and vortical solitons as well as the gap-type soliton clusters. The latter soliton family resembles the recently-found gap waves. We uncover that, unlike the conventional case, the fractional model exhibiting fractional diffraction order strongly influences the formation of higher band gaps. Hence, a new route for the study of self-trapped modes in these newly emergent higher band gaps is suggested. Regimes of stability and instability of all the soliton families are obtained with the help of linear-stability analysis and direct simulations.
A robust hybrid nanozyme@hydrogel platform as a biomimetic cascade bioreactor for combination antitumor therapy
Authors: Hao Yijun , Liu Yandi , Wu Yingjiao , Tao Na , Lou Dongyang , Li Juan , Sun Xiaoyi , Liu You-Nian
Published: January 2020

The development of highly effective and minimally invasive approaches for cancer treatment is the ultimate goal.
Optimisation of pyruvate hyperpolarisation using SABRE by tuning the active magnetisation transfer catalyst
Authors: Tickner Ben. J. , Semenova Olga , Iali Wissam , Rayner Peter J. , Whitwood Adrian C. , Duckett Simon B.
Published: January 2020

SABRE catalysts [Ir(H)2(η2-pyruvate)(sulfoxide)(NCH) transfer magnetisation from para-hydrogen to pyruvate yielding hyperpolarised 13C NMR signals enhanced by >2000-fold. Properties of the catalyst control efficiency.
3D Ni and Co redox-active metal–organic frameworks based on ferrocenyl diphosphinate and 4,4′-bipyridine ligands as efficient electrocatalysts for the hydrogen evolution reaction
Authors: Khrizanforova Vera , Shekurov Ruslan , Miluykov Vasily , Khrizanforov Mikhail , Bon Volodymyr , Kaskel Stefan , Gubaidullin Aidar , Sinyashin Oleg , Budnikova Yulia
Published: January 2020

New 3D Ni and Co redox-active metal–organic frameworks based on ferrocenyl diphosphinate and 4,4′-bipyridine ligands have been explored as efficient electrocatalysts with superior long-term durability in a hydrogen evolution reaction.
Replacing methanol with azeotropic ethanol as the co-solvent for improved chiral separations with supercritical fluid chromatography (SFC)
Authors: Roy Daipayan , Wahab M. Farooq , Talebi Mohsen , Armstrong Daniel W.
Published: January 2020

Using azeoptropic ‘190 proof’ ethanol eliminates the use of methanol in chiral super/subcritical fluid chromatography.
Nanoscale crystallization of a low band gap polymer in printed titania mesopores
Authors: Li Nian , Song Lin , Hohn Nuri , Saxena Nitin , Cao Wei , Jiang Xinyu , Müller-Buschbaum Peter
Published: January 2020

The crystallization behavior of the low band gap polymer induced in printed mesoporous titania films with different pore sizes is studied to optimize the crystal orientation for an application in hybrid solar cells.
A soft-chemistry assisted strong metal–support interaction on a designed plasmonic core–shell photocatalyst for enhanced photocatalytic hydrogen production
Authors: Gesesse Getaneh Diress , Wang Cong , Chang Bor Kae , Tai Shih-Hsuan , Beaunier Patricia , Wojcieszak Robert , Remita Hynd , Colbeau-Justin Christophe , Ghazzal Mohamed Nawfal
Published: January 2020

Engineering photocatalysts based on gold nanoparticles has emerged as new strategy to improve the solar energy conversion.
Synthesis of rhodium(iii)-catalyzed isoquinoline derivatives from allyl carbonates and benzimidates with hydrogen evolution
Authors: Li Chao , Xu Hui-Bei , Zhang Jing , Liu Man , Dong Lin
Published: January 2020

A novel Rh(iii)-catalyzed cascade C–H activation/cyclization approach to access isoquinoline derivatives from benzimidates and available allyl carbonates with the liberation of H2 has been realized.
Natural lignin nanoparticles: a promising nano-crosslinker for constructing fluorescent photoswitchable supramolecular hydrogels
Authors: Gu Lianghong , Liu Xue , Dong Shumin , Chen Zhijun , Han Rui , He Chao , Wang Dongsheng , Zheng Yonghao
Published: January 2020

Photoswitchable and photoluminescent ternary supramolecular hydrogels were fabricated by host–guest and ionic interactions between polyacrylic acid, azobenzene guanidine and α-cyclodextrin grafted cellulolytic enzyme lignin nanoparticles.
Improving the performance of a titanium carbide MXene in supercapacitors by partial oxidation treatment
Authors: Zhang Miao , Chen Xifan , Sui Jinyi , Abraha Bahreselam Sielu , Li Yang , Peng Wenchao , Zhang GuoLiang , Zhang Fengbao , Fan Xiaobin
Published: January 2020

We developed a new strategy to controllably oxidize Ti3C2Tx by readily adjusting the loading of ammonium persulfate, in order to turn the –F terminal groups to –O terminal groups on the Ti3C2Tx MXene, contributing to high performance.
PEGylated gold nanorods with a broad absorption band in the first near-infrared window for in vivo multifunctional photoacoustic imaging
Authors: Wang Yiping , Wu Yiduo , Wen Qiang , Li Pengwei , Wang Ying , Jiang Huabei , Zhang Wendong
Published: January 2020

PEGylated gold nanorods with broad absorption band and their enhanced photoacoustic performance.
Packing transitions in the elastogranular confinement of a slender loop
Authors: Schunter David J. , Czech Regina K. , Holmes Douglas P.
Published: January 2020

An elastic loop, lengthening in a 2D granular array, will buckle into a characteristic folded or circular packing morphology.
A structure–dynamics relationship in ratcheted colloids: resonance melting, dislocations, and defect clusters
Authors: Khali Shubhendu Shekhar , Chakraborty Dipanjan , Chaudhuri Debasish
Published: January 2020

We consider a two dimensional colloidal dispersion of soft-core particles driven by a one dimensional stochastic flashing ratchet that induces a time averaged directed particle current through the system.
Self-assembled toron-like structures in inverse nematic gels
Authors: Topnani Neha B. , Posnjak Gregor , Nagaraja Prutha , Neogi Arkalekha , Musevic Igor , Ramarao Pratibha
Published: January 2020

Inverse nematic gels stabilized by topologically protected localized toron-like structures induced by chiral gelator fibres
Nanomaterial-based biosensors for DNA methyltransferase assay
Authors: Ma Fei , Zhang Qian , Zhang Chun-yang
Published: January 2020

We review the recent advances in the development of nanomaterial-based biosensors for DNA methyltransferase assay.
Stretchable and tough conductive hydrogels for flexible pressure and strain sensors
Authors: Wang Zhenwu , Cong Yang , Fu Jun
Published: January 2020

This review summarises recent advances in stretchable and tough conductive hydrogel sensors for wearable and implantable devices.
Correction: Benefits of the ipowder® extraction process applied to Melissa officinalis L.: improvement of antioxidant activity and in vitro gastro-intestinal release profile of rosmarinic acid
Authors: Bardot Valérie , Escalon Anaïs , Ripoche Isabelle , Denis Sylvain , Alric Monique , Chalancon Sandrine , Chalard Pierre , Cotte César , Berthomier Lucile , Leremboure Martin , Dubourdeaux Michel
Published: January 2020

Correction for ‘Benefits of the ipowder® extraction process applied to Melissa officinalis L.: improvement of antioxidant activity and in vitro gastro-intestinal release profile of rosmarinic acid’ by Valérie Bardot et al., Food Funct., 2020, DOI: 10.1039/c9fo01144g.
Analysis and experimental verification of a novel field modulated permanent magnet gear machine
Authors: Zhou Kaikai , Ge Yanjun , Yang Junyue
Published: January 2020

In order to make more effective use of space in the electric machine, a novel field modulated permanent magnet gear (FMPMG) machine is proposed. The key design aspect of the proposed FMPMG machine is adopting an inner rotor configuration and a specially designed stator core, with fixed modulator pieces, to improve the fabrication feasibility and rotation reliability. Harmonic analysis with detailed theoretical derivation is performed and reveals that the modulator pieces fixed to the stator can modulate the flux density distribution as well and realise a magnetic‐gearing effect. The major parameters are designed and modelled by the 2D finite element method (FEM). First, based on the simulation analyses of the radial flux density distribution in the ‘pseudo’ outer and inner air gap, the specially designed stator is verified to create a nested magnetic‐gearing effect together with the rotor PMs. The back electromagnetic force and electromagnetic torque waveform are further analysed, and the results indicate that the proposed FMPMG machine is more suitable for use as a sinusoidal excitation drive. Finally, a prototype is fabricated for experimentation to further verify the theoretical and FEM simulative validity of the proposed FMPMG machine.
IES configuration method considering peak‐valley differences of tie lines and operation costs of power grids
Authors: Zhang Xiaohui , Li Jiaxin , Zhang Lu , Wu Bangxu , Wang Liang , Tang Wei , Chen Hui , Guo Yunjing
Published: January 2020

The peak–valley difference of power grid will be enlarged significantly with the increasing number of integrated energy systems (IESs) connecting to power grids, which may cause a high operation cost and voltage violations. This study proposes an IES configuration method considering the peak–valley difference of the tie line between IES and power grid. An optimal configuration model of IES is established, which takes the sum of the annual operating cost of the power grid and annual cost of IES as objectives, while the tie line transmission power between IES and power grid are considered as constraints. The elite energy reserve genetic algorithm and branch and bound method are used to solve the proposed model, while the optimal power flow is used to calculate the grid operation cost under a given transmission power of the tie line. The simulation results of an improved IEEE30 node system verify the validity of the proposed method.
Vision‐based approach for predicting the probability of vehicle–pedestrian collisions at intersections
Authors: Zhou Zhuping , Peng Yunlong , Cai Yifei
Published: January 2020

Road accidents impose serious problems on society. Possible collisions between vehicles and pedestrians must be detected before they occur so that a timely warning may be issued. By using the vision‐based approach, this study presents an effective and efficient algorithm to estimate the vehicle–pedestrian collision probability at intersections. The real‐time trajectories and movement parameters (position, speed, acceleration or direction) of vehicles and pedestrians are obtained based on state‐of‐the‐art detection and tracking algorithm which include background subtraction method, faster regions with convolutional neural networks and optical flow method. To find the appropriate time to identify the latent collision risk for calculating the collision probability, this study defines the critical time based on different collision patterns of perception‐reaction failure and evasive action failure. In addition, based on discrete acceleration and discrete angle, the authors get different extended trajectories which can include most situation when the conflict happened. Trajectories generation probability are given by the discrete choice probability model based on the Logit model to get the accurate collision probability. Real‐world video data is implemented to demonstrate the approach. This proposed collision prediction method can provide some important results for designing the intelligent pedestrian signal timing schemes at intersections.
Radial basis function Kalman filter for attitude estimation in GPS‐denied environment
Authors: Assad Ammar , Khalaf Wassim , Chouaib Ibrahim
Published: January 2020

This study presents a radial basis function (RBF) aided extended Kalman filter (EKF) (namely, novel RBFEKF: NRBFEKF) to improve attitude estimation solutions in GPS‐Denied environments. The NRBFEKF has been developed and applied for attitude estimation using only the outputs of strap‐down IMU (gyroscopes and accelerometers) and strap‐down magnetometer. In general, neural networks have the capability to map input–output relationships of a system without a‐priori knowledge about them. A properly designed RBF neural network is able to learn and extract complex relationships given enough training. Furthermore, if there is a platform with inputs, outputs and many sensors, the RBF is able to adapt all the changes of sensors output. The RBFEKF, which is based on EKF aided by RBF network is validated in Matlab environment using simulated trip data and real data acquired during an UAV's trip. The RBFEKF has increased the accuracy of attitude estimation compared to typical EKF. In addition, the RBF is trained to map the vehicle manoeuvre for tuning measurement noise covariance matrix. Simulation results show that estimated measurement noise covariance matrix is closed to the nominal values in cruise flight (stationary phase), while in non‐stationary phase the trained RBF neglects measurements from accelerometers, where accelerometer measurement model is not valid during this phase.
Efficient modeling of correlated noise
Authors: Delisle J.-B. , Hara N. , Ségransan D.
Published: January 2020

Periodograms are common tools used to search for periodic signals in unevenly spaced time series. The significance of periodogram peaks is often assessed using false alarm probability (FAP), which in most studies assumes uncorrelated noise and is computed using numerical methods such as bootstrapping or Monte Carlo. These methods have a high computational cost, especially for low FAP levels, which are of most interest. We present an analytical estimate of the FAP of the periodogram in the presence of correlated noise, which is fundamental to analyze astronomical time series correctly. The analytical estimate that we derive provides a very good approximation of the FAP at a much lower cost than numerical methods. We validate our analytical approach by comparing it with Monte Carlo simulations. Finally, we discuss the sensitivity of the method to different assumptions in the modeling of the noise.
Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars
Authors: Bensby T. , Feltzing S. , Yee J. C. , Johnson J. A. , Gould A. , Asplund M. , Meléndez J. , Lucatello S.
Published: January 2020

Lithium abundances are presented for 91 dwarf and subgiant stars in the Galactic bulge. The analysis is based on line synthesis of the 7Li line at 6707 Å in high-resolution spectra obtained during gravitational microlensing events, when the brightnesses of the targets were highly magnified. Our main finding is that bulge stars at sub-solar metallicities that are older than about eight billion years do not show any sign of Li production; that is, the Li trend with metallicity is flat or even slightly declining. This indicates that no lithium was produced during the first few billion years in the history of the bulge. This finding is essentially identical to what is seen for the (old) thick disk stars in the solar neighbourhood, and adds another piece of evidence for a tight connection between the metal-poor bulge and the Galactic thick disk. For the bulge stars younger than about eight billion years, the sample contains a group of stars at very high metallicities at [Fe/H] ≈ +0.4 that have lithium abundances in the range A(Li) = 2.6 − 2.8. In the solar neighbourhood the lithium abundances have been found to peak at A(Li) ≈ 3.3 at [Fe/H] ≈ +0.1 and then decrease by 0.4–0.5 dex when reaching [Fe/H] ≈ +0.4. The few bulge stars that we have at these metallicities seem to support this declining A(Li) trend. This could indeed support the recent claim that the low A(Li) abundances at the highest metallicities seen in the solar neighbourhood could be due to stars from the inner disk, or the bulge region, that have migrated to the solar neighbourhood.
Ambiguïtés de la norme et réticences face à la prescription à la fin du XVIIe siècle en France
Authors: Siouffi Gilles
Published: January 2020

On se représente souvent la seconde moitié duXVIIe siècle, en raison de l’importance de ses propositions prescriptives, comme un moment où les discours tenus ont été acceptés et suivis d’effet. C’est au volet « limites » que nous nous intéressons dans cette contribution. Après avoir apporté quelques précisions terminologiques sur ce que l’on peut appeler normes et prescriptions, nous revenons sur les fondements de l’« anti-prescriptivisme » auXVIIe siècle, notamment dans l’espace des « remarques sur la langue », et nous montrons comment ce courant de résistance aux prescriptions a été repris par la culture mondaine de la fin du siècle. Au total, nous considérons que, loin de pouvoir être considérée seulement comme une période de « réglage », la seconde moitié duXVIIe siècle peut être vue au contraire comme un moment conflictuel et polémique, caractérisé par une altération de la normativité traditionnelle de la grammaire et par l’installation de régimes sociaux d’opposition qui rendent difficile tout établissement d’une norme unique adossée à une prescription claire.
À propos du volumePonctuer l’œuvre médiévale. Des signes au sens(Valérie Fasseur et Cécile Rochelois [éd.], 2016. Paris, Droz)
Authors: Cinato Franck
Published: January 2020

Le livre soulève plusieurs interrogations sur la notion même de ponctuation qui y est développée. Ce compte-rendu critique attire l’attention sur quelques confusions relevées dans certaines contributions. Il propose en outre une contre-étude sur un problème paléographique concernant le point d’interrogation et enfin, parce que le terme « ponctuation » semble avoir été employé dans un sens trop large, souhaite apporter des nuances à ce qui apparaît comme une dérive terminologique.
Moteur humain et premier instrument : le corps qui « marche » dans l’œuvre d’Angelo Mosso
Authors: Saraceno Marco
Published: January 2020

L’article étudie l’importance de l’expérience de la marche dans l’œuvre du psychophysiologiste italien Angelo Mosso (1846–1910), internationalement connu pour ses recherches sur la fatigue et précurseur de la physiologie de l’exercice en altitude. Dans son œuvre, la marche apparaît sous différentes formes, en consonance avec sa conception de la science du mouvement. D’un côté, le physiologiste se sert des marches forcées des militaires comme expérience « grandeur nature » pour étudier les effets de la fatigue sur les fonctions organiques ; d’un autre côté, le psychologue se sert de son vécu de marcheur pour étudier le rapport entre modification physiologique et « sensations internes » ; enfin, la marche en montagne revient constamment dans les textes du réformateur social comme exemple d’une « fatigue positive ». À partir de la figure de Mosso, l’article s’interroge sur la place du « corps qui marche » dans le développement de la psychophysiologie à la fin du positivisme. D’un côté, le corps qui marche est objectivé et mesuré comme exemple du rendement énergétique ; de l’autre il est exalté et mythifié comme rempart romantique contre la dégénérescence du corps sédentaire et mécanisé de la ville industrielle. Enfin, entre ses deux extrêmes, on voit émerger une réflexion sur l’effort comme « instrumentalisation de soi ».
Vertrauen statt Kontrolle
Authors: Hantl-Merget Judith , Rittner Anna-Maria
Published: January 2020

Steile Hierarchien und enge Kontrollen sind längst nicht mehr zeitgemäß, doch in Kliniken nach wie vor gang und gäbe. Die RoMed Kliniken in Bayern gehen aber einen anderen Weg, hin zu flachen Strukturen und einer selbstorganisierten Führung.
Dynamics of laser-induced cavitation bubbles at a solid–liquid interface in high viscosity and high capillary number regimes
Authors: Hupfeld Tim , Laurens Gaétan , Merabia Samy , Barcikowski Stephan , Gökce Bilal , Amans David
Published: January 2020

No unified model is available yet to explain the dynamics of laser-induced cavitation bubbles during laser ablation of solid targets in liquids, when an extremely high capillary number is achieved (>100), i.e., when the viscous forces strongly contribute to the friction. By investigating laser-induced bubbles on gold and yttrium-iron-garnet targets as a function of the liquid viscosity, using a nanosecond laser and an ultrafast shadowgraph imaging setup, we give a deeper insight into what determines the bubble dynamics. We find that the competition between the viscous forces and the surface tension (capillary number Ca), on the one hand, and the competition between the viscous forces and inertia (Reynolds number Re), on the other hand, are both key factors. Increasing the viscous forces, and hereby Ca up to 100 has an impact on the bubble shape and results in a very pronounced rim, which separates the bubble in a spherical cap driven by inertia and an interlayer. The temporal evolution of the footprint radius of the interlayer can be addressed in the framework of the inertiocapillary regime. For an intermediate viscosity, the thickness of the interlayer is consistent with a boundary layer equation. Interestingly, our data cannot be interpreted with simplified hydrodynamic (Cox–Voinov) or molecular-kinetic theory models, highlighting the originality of the dynamics reported when extremely high capillary numbers are achieved. Upon bubble collapse, spherical persistent microbubbles are created and partly dispersed in water, whereas the high-viscous polyalphaolefines lead to long-standing oblate persistent bubbles sticking to the target’s surface, independent of the ablated target. Overall, liquid’s viscosity determines laser ablation-induced cavitation.
A novel experimental setup for an oblique impact onto an inclined granular layer
Authors: Takizawa Shinta , Yamaguchi Ryusei , Katsuragi Hiroaki
Published: January 2020

We develop an original apparatus of the granular impact experiment by which the incident angle of the solid projectile and the inclination angle of the target granular layer can be systematically varied. Whereas most of the natural cratering events occur on inclined surfaces with various incident angles, there have not been any experiments on oblique impacts on an inclined target surface. To perform systematic impact experiments, a novel experimental apparatus has to be developed. Therefore, we build an apparatus for impact experiments where both the incident angle and the inclination angle can be independently varied. The projectile-injection unit accelerates a plastic ball (6 mm in diameter) up to vi ≃ 100 m s−1 impact velocity. The barrel of the injection unit is made with a three-dimensional printer. The impact dynamics is captured by using high-speed cameras to directly measure the impact velocity and incident angle. The rebound dynamics of the projectile (restitution coefficient and rebound angle) is also measured. The final crater shapes are measured using a line-laser profiler mounted on the electric stages. By scanning the surface using this system, a three-dimensional crater shape (height map) can be constructed. From the measured result, we can define and measure the characteristic quantities of the crater. The analyzed result on the restitution dynamics is presented as an example of systematic experiments using the developed system.
Effect of compressibility on the local flow topology in homogeneous shear turbulence
Authors: Wang Xiaoning , Chen Song , Wang Jianchun , Li Hui , Wan Minping , Chen Shiyi
Published: January 2020

The local flow topology based on the invariants of the velocity gradient tensor in stationary compressible homogeneous shear turbulence (HST) is studied by numerical simulations. In the compressible homogeneous shear turbulence, local compressibility decreases the flow volume fraction occupied by the focal, eddy, and shear flow structures both in compression regions and in strong expansion regions. The joint probability density function (pdf) of the second and third invariants of the deviatoric velocity gradient tensor exhibits a similar teardrop shape as for the homogeneous isotropic turbulence (HIT), and the tail of the joint pdf alongside the right branch of the null-discriminant curve is elongated as the turbulent Mach number increases. When conditioned on dilatation, the statistical preference for points in the fourth quadrants of the joint pdf is enhanced significantly by the compression motion. It is found that the shape of the joint pdf shows a good similarity between HST and HIT in strong compression regions, which is dependent on the root mean square dilatation, rather than the turbulent Mach number. In strong expansion regions, the shape of the joint pdf in HST has a long tail in the third quadrant, which is related to sheetlike expansion structures and does not exist in HIT. After the Helmholtz decomposition, the properties of local flow topology associated with the solenoidal component of the velocity field are found to be very similar to those in incompressible turbulence and are insensitive to the change in local dilatation and turbulent Mach number.
In situ wavelength tuning of quantum-dot single-photon sources integrated on a CMOS-processed silicon waveguide
Authors: Katsumi Ryota , Ota Yasutomo , Osada Alto , Tajiri Takeyoshi , Yamaguchi Takuto , Kakuda Masahiro , Iwamoto Satoshi , Akiyama Hidefumi , Arakawa Yasuhiko
Published: January 2020

Silicon quantum photonics provides a promising pathway to realize large-scale quantum photonic integrated circuits (QPICs) by exploiting the power of complementary-metal-oxide-semiconductor (CMOS) technology. Toward scalable operation of such silicon-based QPICs, a straightforward approach is to integrate deterministic single-photon sources (SPSs). To this end, hybrid integration of deterministic solid-state SPSs, such as those based on InAs/GaAs quantum dots (QDs), is highly promising. However, the spectral and spatial randomness inherent in the QDs poses a serious challenge for scalable implementation of multiple identical SPSs on a silicon CMOS chip. To overcome this challenge, we have been investigating a hybrid integration technique called transfer printing, which is based on a pick-and-place operation and allows for the integration of the desired QD SPSs on any locations on the silicon CMOS chips at will. Nevertheless, even in this scenario, in situ fine tuning for perfect wavelength matching among the integrated QD SPSs will be required for interfering photons from dissimilar sources. Here, we demonstrate in situ wavelength tuning of QD SPSs integrated on a CMOS silicon chip. To thermally tune the emission wavelengths of the integrated QDs, we augmented the QD SPSs with optically driven heating pads. The integration of all the necessary elements was performed using transfer printing, which largely simplified the fabrication of the three-dimensional stack of micro/nanophotonic structures. We further demonstrate in situ wavelength matching between two dissimilar QD sources integrated on the same silicon chip. Our transfer-printing-based approach will open the possibility for realizing large-scale QPICs that leverage CMOS technology.
Cryogenic characterization of a ferroelectric field-effect-transistor
Authors: Wang Zheng , Ying Hanbin , Chern Winston , Yu Shimeng , Mourigal Martin , Cressler John D. , Khan Asif I.
Published: January 2020

A ferroelectric field-effect transistor (FeFET) with scaled dimensions (170 nm and 24 nm of gate width and length, respectively) and a 10 nm thick Si doped HfO2 ferroelectric in the gate oxide stack are characterized at cryogenic temperatures down to 6.9 K. We observe that a decrease in temperature leads to an increase in the memory window at the expense of an increased program/erase voltage. This is consistent with the increase in the ferroelectric coercive field due to the suppression of thermally activated domain wall creep motion at cryogenic temperatures. However, the observed insensitivity of the location of the memory window with respect to temperature cannot be explained by the current understanding of the device physics of FeFETs. Such temperature dependent studies of scaled FeFETs can lead to useful insights into their underlying device physics, while providing an assessment of the potential of this emerging technology for cryogenic memory applications.
A study of bubble growth in the compressible Rayleigh–Taylor and Richtmyer–Meshkov instabilities
Authors: Zhao Yubin , Xia Mengjiao , Cao Yigang
Published: January 2020

Within the framework of modified Layzer-type potential flow theory [V. N. Goncharov, “Analytical model of nonlinear, single-mode, classical Rayleigh-Taylor instability at arbitrary Atwood numbers,” Phys. Rev. Lett. 88, 134502 (2002)], we study bubble growth in compressible Rayleigh–Taylor (RT) and Richtmyer–Meshkov (RM) instabilities. It is known from adiabatic equations that the density ρ and adiabatic index γ are compressibility-related factors for a given static pressure p. Here, we introduce a dynamically varying stagnation point pressure P̃=p±12ρ̃η̇02, which relates time-varying quantities, such as fluid density ρ̃, pressure P̃, and bubble tip velocity η̇0, and then, we analytically derive the governing equations for time evolution of bubbles in the RT and RM instabilities of compressible fluids. For the RT instability, the upper fluid adiabatic index γu and density ρu increase the bubble amplitude and velocity, but they decrease the bubble curvature radius at the early stage, while the lower fluid adiabatic index γl and density ρl have opposite effects on those of γu and ρu, which is consistent with recent results. For the RM instability, γu and ρu decrease the bubble amplitude and velocity, but they increase the bubble curvature radius at the early stage; however, γl and ρl have opposite effects on those of γu and ρu. Moreover, we find a good agreement between our three-dimensional results of the RM bubble amplitude and recent numerical simulations.
The interaction of polymer dispersed liquid crystal sensors with ultrasound
Authors: Edwards R. S. , Ward J. , Zhou L. Q. , Trushkevych O.
Published: January 2020

Polymer dispersed liquid crystals (PDLCs) have been shown to be sensitive to ultrasound through the acousto-optic effect. The acousto-optic response of PDLCs was studied over a broad frequency range (0.3–10 MHz). We demonstrate that the displacements required to produce acousto-optic clearing of PDLC films can be as low as a few nanometers, which is at least 103 times smaller than the PDLC droplet size, is 105 times smaller than the PDLC layer thickness, and of the order of the molecular size of the liquid crystal constituents. This suggests that the acousto-optic effect in PDLCs is due to the microscopic effects of the LC reorientation under torques or flows rather than the LC reorientation through macroscopic droplet deformation. The displacement required for clearing is related to the frequency of operation via an exponential decay. We attribute the observed frequency response to a freezing out of the rotational motion around the short axis of the liquid crystal. The reported frequency dependence and displacements required indicate that the effects and materials described here could be used for ultrasound visualization in a non-destructive testing context.
Relaxed GaP on Si with low threading dislocation density
Authors: Hool Ryan D. , Chai Yuji , Sun Yukun , Eng Brendan C. , Dhingra Pankul , Fan Shizhao , Nay Yaung Kevin , Lee Minjoo Larry
Published: January 2020

We demonstrate a two-step procedure for the growth of relaxed GaP on pseudomorphic GaP/Si templates with a threading dislocation density (TDD) of 1.0–1.1 × 106 cm−2. In lattice-mismatched epitaxy, suppressed dislocation nucleation and unimpeded dislocation glide during relaxation are both critical to achieve a low TDD. Our two-step growth process realizes the former by initiating growth with a thin, low growth temperature (Tgrowth) layer and the latter with a subsequent high-Tgrowth layer. In optimizing the low-Tgrowth layer thickness, we find a trade-off where too little thickness does not suppress dislocation nucleation, while too much thickness takes away the advantage of higher dislocation velocity at high-Tgrowth. Dislocation pileups and trenches are identified as heterogeneous features with a very high local TDD that commonly arise during single-step growth of GaP on Si at high-Tgrowth, and two-step growth virtually eliminates their formation. Overall, this work shows that after initiation at low-Tgrowth, subsequent epitaxy can be performed at high-Tgrowth while avoiding rampant dislocation nucleation, as well as formation of trenches and dislocation pileups.
Microrobots designed to pick up and place particles
Authors: Mandel Savannah
Published: January 2020

Using an electromagnetic control system, capillary interactions and visual feedback, scientists move passive particles with a microrobot.
Localisation and function of glucose transporter GLUT1 in chicken (Gallus gallus domesticus) spermatozoa: relationship between ATP production pathways and flagellar motility
Authors: Setiawan Rangga , Priyadarshana Chathura , Tajima Atsushi , Travis Alexander J. , Asano Atsushi
Published: January 2020

Glucose plays an important role in sperm flagellar motility and fertility via glycolysis and oxidative phosphorylation, although the primary mechanisms for ATP generation vary between species. The glucose transporter 1 (GLUT1) is a high-affinity isoform and a major glucose transporter in mammalian spermatozoa. However, in avian spermatozoa, the glucose metabolic pathways are poorly characterised. This study demonstrates that GLUT1 plays a major role in glucose-mediated motility of chicken spermatozoa. Using specific antibodies and ligand, we found that GLUT1 was specifically localised to the midpiece. Sperm motility analysis showed that glucose supported sperm movement during incubation for 0–80min. However, this was abolished by the addition of a GLUT1 inhibitor, concomitant with a substantial decrease in glucose uptake and ATP production, followed by elevated mitochondrial activity in response to glucose addition. More potent inhibition of ATP production and mitochondrial activity was observed in response to treatment with uncouplers of oxidative phosphorylation. Because mitochondrial inhibition only reduced a subset of sperm movements, we investigated the localisation of the glycolytic pathway and showed glyceraldehyde-3-phosphate dehydrogenase and hexokinase I at the midpiece and principal piece of the flagellum. The results of this study provide new insights into the mechanisms involved in ATP production pathways in avian spermatozoa.
Influence of Arctic sea-ice variability on Pacific trade winds
Authors: Kennel Charles F. , Yulaeva Elena
Published: January 2020

A conceptual model connecting seasonal loss of Arctic sea ice to midlatitude extreme weather events is applied to the 21st-century intensification of Central Pacific trade winds, emergence of Central Pacific El Nino events, and weakening of the North Pacific Aleutian Low Circulation. According to the model, Arctic Ocean warming following the summer sea-ice melt drives vertical convection that perturbs the upper troposphere. Static stability calculations show that upward convection occurs in annual 40- to 45-d episodes over the seasonally ice-free areas of the Beaufort-to-Kara Sea arc. The episodes generate planetary waves and higher-frequency wave trains that transport momentum and heat southward in the upper troposphere. Regression of upper tropospheric circulation data on September sea-ice area indicates that convection episodes produce wave-mediated teleconnections between the maximum ice-loss region north of the Siberian Arctic coast and the Intertropical Convergence Zone (ITCZ). These teleconnections generate oppositely directed trade-wind anomalies in the Central and Eastern Pacific during boreal winter. The interaction of upper troposphere waves with the ITCZ air–sea column may also trigger Central Pacific El Nino events. Finally, waves reflected northward from the ITCZ air column and/or generated by triggered El Nino events may be responsible for the late winter weakening of the Aleutian Low Circulation in recent years.
Diversity buffers winegrowing regions from climate change losses
Authors: Morales-Castilla Ignacio , García de Cortázar-Atauri Iñaki , Cook Benjamin I. , Lacombe Thierry , Parker Amber , van Leeuwen Cornelis , Nicholas Kimberly A. , Wolkovich Elizabeth M.
Published: January 2020

Agrobiodiversity—the variation within agricultural plants, animals, and practices—is often suggested as a way to mitigate the negative impacts of climate change on crops [S. A. Woodet al.,Trends Ecol. Evol.30, 531–539 (2015)]. Recently, increasing research and attention has focused on exploiting the intraspecific genetic variation within a crop [Hajjaret al.,Agric. Ecosyst. Environ.123, 261–270 (2008)], despite few relevant tests of how this diversity modifies agricultural forecasts. Here, we quantify how intraspecific diversity, via cultivars, changes global projections of growing areas. We focus on a crop that spans diverse climates, has the necessary records, and is clearly impacted by climate change: winegrapes (predominantlyVitis viniferasubspeciesvinifera). We draw on long-term French records to extrapolate globally for 11 cultivars (varieties) with high diversity in a key trait for climate change adaptation—phenology. We compared scenarios where growers shift to more climatically suitable cultivars as the climate warms or do not change cultivars. We find that cultivar diversity more than halved projected losses of current winegrowing areas under a 2 °C warming scenario, decreasing areas lost from 56 to 24%. These benefits are more muted at higher warming scenarios, reducing areas lost by a third at 4 °C (85% versus 58%). Our results support the potential of in situ shifting of cultivars to adapt agriculture to climate change—including in major winegrowing regions—as long as efforts to avoid higher warming scenarios are successful.
Landscape context affects the sustainability of organic farming systems
Authors: Smith Olivia M. , Cohen Abigail L. , Reganold John P. , Jones Matthew S. , Orpet Robert J. , Taylor Joseph M. , Thurman Jessa H. , Cornell Kevin A. , Olsson Rachel L. , Ge Yang , Kennedy Christina M. , Crowder David W.
Published: January 2020

Significance

Organic agriculture promotes environmental and socioeconomic sustainability to a greater degree than conventional agriculture. However, it is unknown whether effects of organic agriculture on sustainability metrics such as biodiversity, crop yields, and profitability vary across the diverse landscapes where organic farming is practiced. We addressed this using a global meta-analysis spanning 60 crops. Organic sites had greater biodiversity than conventional ones, with the largest benefits in landscapes with large field sizes. In contrast, while organic sites also had greater profits, the largest benefits occurred in landscapes with small fields. The ecological sustainability benefits of organic agriculture are most pronounced in landscapes typified by more intensive agriculture, while economic benefits are likely influenced by socioeconomic factors and yields.
The unreasonable effectiveness of deep learning in artificial intelligence
Authors: Sejnowski Terrence J.
Published: January 2020

Deep learning networks have been trained to recognize speech, caption photographs, and translate text between languages at high levels of performance. Although applications of deep learning networks to real-world problems have become ubiquitous, our understanding of why they are so effective is lacking. These empirical results should not be possible according to sample complexity in statistics and nonconvex optimization theory. However, paradoxes in the training and effectiveness of deep learning networks are being investigated and insights are being found in the geometry of high-dimensional spaces. A mathematical theory of deep learning would illuminate how they function, allow us to assess the strengths and weaknesses of different network architectures, and lead to major improvements. Deep learning has provided natural ways for humans to communicate with digital devices and is foundational for building artificial general intelligence. Deep learning was inspired by the architecture of the cerebral cortex and insights into autonomy and general intelligence may be found in other brain regions that are essential for planning and survival, but major breakthroughs will be needed to achieve these goals.