bluuebunny/crossref_metadata_2025_split huggingface dataset:
Open database analysis of scaling and spatio-temporal properties of power grid frequencies
Authors: Rydin Gorjão Leonardo , Jumar Richard , Maass Heiko , Hagenmeyer Veit , Yalcin G. Cigdem , Kruse Johannes , Timme Marc , Beck Christian , Witthaut Dirk , Schäfer Benjamin 
Published: December 2020

AbstractThe electrical energy system has attracted much attention from an increasingly diverse research community. Many theoretical predictions have been made, from scaling laws of fluctuations to propagation velocities of disturbances. However, to validate any theory, empirical data from large-scale power systems are necessary but are rarely shared openly. Here, we analyse an open database of measurements of electric power grid frequencies across 17 locations in 12 synchronous areas on three continents. The power grid frequency is of particular interest, as it indicates the balance of supply and demand and carries information on deterministic, stochastic, and control influences. We perform a broad analysis of the recorded data, compare different synchronous areas and validate a previously conjectured scaling law. Furthermore, we show how fluctuations change from local independent oscillations to a homogeneous bulk behaviour. Overall, the presented open database and analyses constitute a step towards more shared, collaborative energy research.
Deep learning-based cross-classifications reveal conserved spatial behaviors within tumor histological images
Authors: Noorbakhsh Javad , Farahmand Saman , Foroughi pour Ali , Namburi Sandeep , Caruana Dennis , Rimm David , Soltanieh-ha Mohammad , Zarringhalam Kourosh , Chuang Jeffrey H. 
Published: December 2020

AbstractHistopathological images are a rich but incompletely explored data type for studying cancer. Manual inspection is time consuming, making it challenging to use for image data mining. Here we show that convolutional neural networks (CNNs) can be systematically applied across cancer types, enabling comparisons to reveal shared spatial behaviors. We develop CNN architectures to analyze 27,815 hematoxylin and eosin scanned images from The Cancer Genome Atlas for tumor/normal, cancer subtype, and mutation classification. Our CNNs are able to classify TCGA pathologist-annotated tumor/normal status of whole slide images (WSIs) in 19 cancer types with consistently high AUCs (0.995 ± 0.008), as well as subtypes with lower but significant accuracy (AUC 0.87 ± 0.1). Remarkably, tumor/normal CNNs trained on one tissue are effective in others (AUC 0.88 ± 0.11), with classifier relationships also recapitulating known adenocarcinoma, carcinoma, and developmental biology. Moreover, classifier comparisons reveal intra-slide spatial similarities, with an average tile-level correlation of 0.45 ± 0.16 between classifier pairs. Breast cancers, bladder cancers, and uterine cancers have spatial patterns that are particularly easy to detect, suggesting these cancers can be canonical types for image analysis. Patterns for TP53 mutations can also be detected, with WSI self- and cross-tissue AUCs ranging from 0.65-0.80. Finally, we comparatively evaluate CNNs on 170 breast and colon cancer images with pathologist-annotated nuclei, finding that both cellular and intercellular regions contribute to CNN accuracy. These results demonstrate the power of CNNs not only for histopathological classification, but also for cross-comparisons to reveal conserved spatial behaviors across tumors.
Quantifying accuracy and heterogeneity in single-molecule super-resolution microscopy
Authors: Mazidi Hesam , Ding Tianben , Nehorai Arye , Lew Matthew D. 
Published: December 2020

AbstractThe resolution and accuracy of single-molecule localization microscopes (SMLMs) are routinely benchmarked using simulated data, calibration rulers, or comparisons to secondary imaging modalities. However, these methods cannot quantify the nanoscale accuracy of an arbitrary SMLM dataset. Here, we show that by computing localization stability under a well-chosen perturbation with accurate knowledge of the imaging system, we can robustly measure the confidence of individual localizations without ground-truth knowledge of the sample. We demonstrate that our method, termed Wasserstein-induced flux (WIF), measures the accuracy of various reconstruction algorithms directly on experimental 2D and 3D data of microtubules and amyloid fibrils. We further show that WIF confidences can be used to evaluate the mismatch between computational models and imaging data, enhance the accuracy and resolution of reconstructed structures, and discover hidden molecular heterogeneities. As a computational methodology, WIF is broadly applicable to any SMLM dataset, imaging system, and localization algorithm.
High-resolution ex vivo NMR spectroscopy of human Z α1-antitrypsin
Authors: Jagger Alistair M. , Waudby Christopher A. , Irving James A. , Christodoulou John , Lomas David A. 
Published: December 2020

AbstractGenetic mutations predispose the serine protease inhibitor α1-antitrypsin to misfolding and polymerisation within hepatocytes, causing liver disease and chronic obstructive pulmonary disease. This misfolding occurs via a transiently populated intermediate state, but our structural understanding of this process is limited by the instability of recombinant α1-antitrypsin variants in solution. Here we apply NMR spectroscopy to patient-derived samples of α1-antitrypsin at natural isotopic abundance to investigate the consequences of disease-causing mutations, and observe widespread chemical shift perturbations for methyl groups in Z AAT (E342K). By comparison with perturbations induced by binding of a small-molecule inhibitor of misfolding we conclude that they arise from rapid exchange between the native conformation and a well-populated intermediate state. The observation that this intermediate is stabilised by inhibitor binding suggests a paradoxical approach to the targeted treatment of protein misfolding disorders, wherein the stabilisation of disease-associated states provides selectivity while inhibiting further transitions along misfolding pathways.
Automation and control of laser wakefield accelerators using Bayesian optimization
Authors: Shalloo R. J. , Dann S. J. D. , Gruse J.-N. , Underwood C. I. D. , Antoine A. F. , Arran C. , Backhouse M. , Baird C. D. , Balcazar M. D. , Bourgeois N. , Cardarelli J. A. , Hatfield P. , Kang J. , Krushelnick K. , Mangles S. P. D. , Murphy C. D. , Lu N. , Osterhoff J. , Põder K. , Rajeev P. P. , Ridgers C. P. , Rozario S. , Selwood M. P. , Shahani A. J. , Symes D. R. , Thomas A. G. R. , Thornton C. , Najmudin Z. , Streeter M. J. V. 
Published: December 2020

AbstractLaser wakefield accelerators promise to revolutionize many areas of accelerator science. However, one of the greatest challenges to their widespread adoption is the difficulty in control and optimization of the accelerator outputs due to coupling between input parameters and the dynamic evolution of the accelerating structure. Here, we use machine learning techniques to automate a 100 MeV-scale accelerator, which optimized its outputs by simultaneously varying up to six parameters including the spectral and spatial phase of the laser and the plasma density and length. Most notably, the model built by the algorithm enabled optimization of the laser evolution that might otherwise have been missed in single-variable scans. Subtle tuning of the laser pulse shape caused an 80% increase in electron beam charge, despite the pulse length changing by just 1%.
Structure-based dynamic analysis of the glycine cleavage system suggests key residues for control of a key reaction step
Authors: Zhang Han , Li Yuchen , Nie Jinglei , Ren Jie , Zeng An-Ping 
Published: December 2020

AbstractMolecular shuttles play decisive roles in many multi-enzyme systems such as the glycine cleavage system (GCS) for one-carbon (C1) metabolism. In GCS, a lipoate swinging arm containing an aminomethyl moiety is attached to protein H and serves as a molecular shuttle among different proteins. Protection of the aminomethyl moiety in a cavity of protein H and its release induced by protein T are key processes but barely understood. Here, we present a detailed structure-based dynamic analysis of the induced release of the lipoate arm of protein H. Based on molecular dynamics simulations of interactions between proteins H and T, four major steps of the release process showing significantly different energy barriers and time scales can be distinguished. Mutations of a key residue, Ser-67 in protein H, led to a bidirectional tuning of the release process. This work opens ways to target C1 metabolism in biomedicine and the utilization of formate and CO2for biosynthesis.
Templated approach to well-defined, oxidatively coupled conjugated polymers
Authors: Pahlavanlu Paniz , Cheng Susan , Battaglia Alicia M. , Hicks Garion E. J. , Jarrett-Wilkins Charles N. , Evariste Sloane , Seferos Dwight S. 
Published: December 2020

Templated oxidative polymerization affords organic soluble, oxidatively doped PEDOT-based polymers with controlled molecular weights and low dispersities (Đ ∼ 1.2) for the first time.
Implementing High-speed Running and Sprinting Training in Professional Soccer
Authors: Beato Marco , Drust Barry , Iacono Antonio Dello 
Published: December 2020

AbstractHigh-speed running and sprinting training play an important role in the development of physical capabilities, sport-specific performance and injury prevention among soccer players. This commentary aims to summarize the current evidence regarding high-speed running and sprinting training in professional soccer and to inform its implementation in research and applied settings. It is structured into four sections: 1) Evidence-based high-speed running and sprinting conditioning methodologies; 2) Monitoring of high-speed running and sprinting performance in soccer 3) Recommendations for effective implementation of high-speed running and sprinting training in applied soccer settings; 4) Limitations and future directions. The contemporary literature provides preliminary methodological guidelines for coaches and practitioners. The recommended methods to ensure high-speed running and sprinting exposure for both conditioning purposes and injury prevention strategies among soccer players are: high-intensity running training, field-based drills and ball-drills in the form of medium- and large-sided games. Global navigation satellite systems are valid and reliable technologies for high-speed running and sprinting monitoring practice. Future research is required to refine, and advance training practices aimed at optimizing individual high-speed running and sprinting training responses and associated long-term effects.
Chemical Modulators of Fibrinogen Production and Their Impact on Venous Thrombosis
Authors: Vilar Rui , Lukowski Samuel W. , Garieri Marco , Di Sanza Corinne , Neerman-Arbez Marguerite , Fish Richard J. 
Published: December 2020

AbstractThrombosis is a leading cause of morbidity and mortality. Fibrinogen, the soluble substrate for fibrin-based clotting, has a central role in haemostasis and thrombosis and its plasma concentration correlates with cardiovascular disease event risk and a prothrombotic state in experimental models. We aimed to identify chemical entities capable of changing fibrinogen production and test their impact on experimental thrombosis. A total of 1,280 bioactive compounds were screened for their ability to alter fibrinogen production by hepatocyte-derived cancer cells and a selected panel was tested in zebrafish larvae. Anthralin and all-trans retinoic acid (RA) were identified as fibrinogen-lowering and fibrinogen-increasing moieties, respectively. In zebrafish larvae, anthralin prolonged laser-induced venous- occlusion times and reduced thrombocyte accumulation at injury sites. RA had opposite effects. Treatment with RA, a nuclear receptor ligand, increased fibrinogen mRNA levels. Using an antisense morpholino oligonucleotide to deplete zebrafish fibrinogen, we correlated a shortening of laser-induced venous thrombosis times with RA treatment and fibrinogen protein levels. Anthralin had little effect on fibrinogen mRNA in zebrafish larvae, despite leading to lower detectable fibrinogen. Therefore, we made a proteomic scan of anthralin-treated cells and larvae. A reduced representation of proteins linked to the canonical secretory pathway was detected, suggesting that anthralin affects protein secretion. In summary, we found that chemical modulation of fibrinogen levels correlates with measured effects on experimental venous thrombosis and could be investigated as a therapeutic avenue for thrombosis prevention.
Hybrid projection methods for large-scale inverse problems with mixed Gaussian priors
Authors: Cho Taewon , Chung Julianne , Jiang Jiahua 
Published: December 2020

Abstract
When solving ill-posed inverse problems, a good choice of the prior is critical for the computation of a reasonable solution. A common approach is to include a Gaussian prior, which is defined by a mean vector and a symmetric and positive definite covariance matrix, and to use iterative projection methods to solve the corresponding regularized problem. However, a main challenge for many of these iterative methods is that the prior covariance matrix must be known and fixed (up to a constant) before starting the solution process. In this paper, we develop hybrid projection methods for inverse problems with mixed Gaussian priors where the prior covariance matrix is a convex combination of matrices and the mixing parameter and the regularization parameter do not need to be known in advance. Such scenarios may arise when data is used to generate a sample prior covariance matrix (e.g., in data assimilation) or when different priors are needed to capture different qualities of the solution. The proposed hybrid methods are based on a mixed Golub–Kahan process, which is an extension of the generalized Golub–Kahan bidiagonalization, and a distinctive feature of the proposed approach is that both the regularization parameter and the weighting parameter for the covariance matrix can be estimated automatically during the iterative process. Furthermore, for problems where training data are available, various data-driven covariance matrices (including those based on learned covariance kernels) can be easily incorporated. Numerical examples from tomographic reconstruction demonstrate the potential for these methods.
Physical modeling of charge transport in conjugated polymer field-effect transistors
Authors: Lee Jiyoul 
Published: December 2020

Abstract
Conjugated polymer field-effect transistors are expected to have considerable potential for widespread use in various applications such as flexible displays, low-cost radio-frequency tags and functional sensors for healthcare systems due to their mechanical flexibility and printing-based low-cost processability on flexible plastic substrates. Therefore, they have witnessed remarkable progress over the last three decades. However, further development of polymer field-effect transistors remains hampered because the charge transport occurring in the active semiconducting polymer layers has not been understood adequately and the device physics has not yet been established completely. This topical review summarizes the physical charge transport models of polymer semiconductors that have been proposed so far and discusses the advantages and disadvantages of each model. Accordingly, the process of analyzing the experimental results by employing the appropriate physical charge transport model is investigated to ultimately facilitate the rational design of advanced semiconducting polymers as well as the fabrication of enhanced organic devices.
Synthesis and characterization of MWCNT-covered stainless steel mesh with Janus-type wetting properties
Authors: Karthikeyan Adya , Kasparek Evelyne , Kietzig Anne-Marie , Girard-Lauriault Pierre-Luc , Coulombe Sylvain 
Published: December 2020

Abstract
Various multi-step methods to fabricate Janus membranes have been reported in literature. However, no article so far reports the durability of the Janus membranes when exposed to liquids. We report on a novel method to fabricate a Janus-type multi-walled carbon nanotubes (MWCNT)-covered stainless steel (SS) mesh, which retains dual-wetting properties even after exposure to water for 540 d. The MWCNTs are grown directly on stainless steel mesh coupons by chemical vapor deposition using acetylene as the carbon source, and are then plasma functionalized using an ammonia-ethylene gas mixture to achieve dual-wettability. We found by x-ray photoelectron spectroscopy that the MWCNTs on the top face of the novel Janus MWCNT-SS mesh, which was directly exposed to the plasma, are coated by a plasma polymer rich in nitrogen-containing functional groups, while the MWCNTs on the bottom face are almost devoid of the plasma polymer coating. Atomic force microscopy studies confirmed that the surface roughness of the bottom face of the mesh is lower than the minimum roughness that allows the capillary ingress of water to sustain its superhydrophobic behavior. In addition, scanning electron microscopy studies also confirmed that the MWCNTs on the bottom face of the treated MWCNT mesh are vertically aligned compared to the MWCNTs on the top face of the mesh. The vertically aligned dense MWCNT forest on the bottom face attributes to its superhydrophobic nature.
Understanding ambipolar transport in MoS2 field effect transistors: the substrate is the key
Authors: Mootheri Vivek , Leonhardt Alessandra , Verreck Devin , Asselberghs Inge , Huyghebaert Cedric , de Gendt Stefan , Radu Iuliana , Lin Dennis , Heyns Marc 
Published: December 2020

Abstract
2D materials offer a pathway for further scaling of CMOS technology. However, for this to become a reality, both n-MOS and p-MOS should be realized, ideally with the same (standard) material. In the specific case of MoS2 field effect transistors (FETs), ambipolar transport is seldom reported, primarily due to the phenomenon of Fermi level pinning (FLP). In this study we identify the possible sources of FLP in MoS2 FETs and resolve them individually. A novel contact transfer technique is used to transfer contacts on top of MoS2 flake devices that results in a significant increase in the hole branch of the transfer characteristics as compared to conventionally fabricated contacts. We hypothesize that the pinning not only comes from the contact-MoS2 interface, but also from the MoS2-substrate interface. We confirm this by shifting to an hBN substrate which leads to a 10 fold increase in the hole current compared to the SiO2 substrate. Furthermore, we analyse MoS2 FETs of different channel thickness on three different substrates, SiO2, hBN and Al2O3, by correlating the p-branch I
ON/I
OFF to the position of oxide defect band in these substrates. FLP from the oxide is reduced in the case of Al2O3 which enables us to observe ambipolar transport in a bilayer MoS2 FET. These results highlight that MoS2 is indeed an ambipolar material, and the absence of ambipolar transport in MoS2 FETs is strongly correlated to its dielectric environment and processing conditions.
Interface-enhanced superconductivity in multi-grain (FeSe)η(SrTiO3)1-η composites
Authors: Zhang Huimin , Dong Wenfeng , Meng Qing-Long , Yin Nan , Liu Zhengmao , Lu Xiaowei , Ge Binghui , Li Yuanzhao , Shi Quan , Wang Lili , Xue Qi-Kun , Jiang Peng , Bao Xinhe 
Published: December 2020

Abstract
Interface superconductivity, realized in multiple artificial crystalline heterostructures, is one of the most exciting directions to search for high-temperature superconductivity. In this work, we prepare bulk (FeSe)
η
(SrTiO3)1−η
multi-grain composites by a simple facile liquid-phase compaction method using a spark-plasma-sintering technique. Combining transmission electron microscopy/scanning electron microscopy and x-ray diffraction investigations, we demonstrate that the composites consist of micron-scale SrTiO3 grains surrounded by [001]-compressed β-FeSe grains. Transport measurements for the composites with FeSe mole fraction η > 0.06 reveal that two superconducting channels, one T
c ∼ 13 K phase from FeSe/SrTiO3 interfaces and another T
c ∼ 7 K phase from FeSe grains, cooperatively induce macroscopic superconducting behavior with isotropic upper critical fields above 40 T. This work points out a straightforward method to enhance T
c in the multi-grain (FeSe)
η
(SrTiO3)1−η
composites by reducing the crystalline grains to nanoscale and finely tuning the stoichiometries of FeSe and SrTiO3.
Ultra-high optical nonreciprocity with a coupled triple-resonator structure
Authors: Cao Zhen , Xie Yi Fei , He Bing , Lin Qing 
Published: December 2020

Abstract
Optical transmission nonreciprocity as a widely investigated phenomenon is essential to various applications. Many sophisticated mechanisms have been proposed and tested for achieving the optical nonreciprocity on integrated scale, but the technical barriers still exist to their practical implementation. To have an ultra-high transmission nonreciprocity, we consider a simple physical mechanism of optical gain saturation applied to a structure of three mutually coupled cavities or fiber rings. The gain saturation processes in two of its components creates a significantly enhanced optical nonreciprocity that satisfies the requirements for the realistic applications. The structure enjoys two advantages of its wide working bandwidth and the flexibility in choosing its components. Moreover, it is possible to apply the structure to a faithful and non-reciprocal transmission of broadband pulse signals. The structure may considerably relax the constraints on the integrated photonic circuits based on the current technology.
Effect of dimensional parameters on the seismic performance of circular CFST columns
Authors: Reshma S , Bushra M A 
Published: December 2020

Abstract
Due to the expansion of cities and increase in population, the need for construction of high rise buildings becomes more essential in the society. As earthquakes are of the greatest damaging natural hazards to the buildings, the design and construction of structures which are capable of resisting the adverse effects of earthquakes become necessary. Concrete Filled Steel Tubes (CFSTs) are the steel tubular sections in-filled with concrete and with a composite action. CFSTs are becoming a popular solution for structures located in seismic areas, due to their high strength, excellent ductility and large energy absorption capacity. This study was mainly concentrated to find out the effect of dimensional parameters on the seismic performance of CFSTs. Width - thickness ratio (D/t) and slenderness ratio (L/D) were taken as two parameters and the study was carried out using circular CFST buildings. It was observed that, there will be a particular limit for D/t and L/D ratio upto which the thickness and diameter of the CFSTs can be decreased. At that point the building will show a better seismic performance.