bluuebunny/crossref_metadata_2025 huggingface dataset:
Patterns and driving forces of dimensionality-dependent charge density waves in 2H-type transition metal dichalcogenides
Authors: Lin Dongjing , Li Shichao , Wen Jinsheng , Berger Helmuth , Forró László , Zhou Huibin , Jia Shuang , Taniguchi Takashi , Watanabe Kenji , Xi Xiaoxiang , Bahramy Mohammad Saeed
Published: May 2020

Charge density wave (CDW) is a startling quantum phenomenon, distorting a metallic lattice into an insulating state with a periodically modulated charge distribution. Astonishingly, such modulations appear in various patterns even within the same family of materials. Moreover, this phenomenon features a puzzling diversity in its dimensional evolution. Here, we propose a general framework, unifying distinct trends of CDW ordering in an isoelectronic group of materials, 2H-MX2 (M = Nb, Ta and X = S, Se). We show that while NbSe2 exhibits a strongly enhanced CDW order in two dimensions, TaSe2 and TaS2 behave oppositely, with CDW being absent in NbS2 entirely. Such a disparity is demonstrated to arise from a competition of ionic charge transfer, electron-phonon coupling, and electron correlation. Despite its simplicity, our approach can, in principle, explain dimensional dependence of CDW in any material, thereby shedding new light on this intriguing quantum phenomenon and its underlying mechanisms.
Measurement-induced, spatially-extended entanglement in a hot, strongly-interacting atomic system
Authors: Kong Jia , Jiménez-Martínez Ricardo , Troullinou Charikleia , Lucivero Vito Giovanni , Tóth Géza , Mitchell Morgan W.
Published: May 2020

Quantum technologies use entanglement to outperform classical technologies, and often employ strong cooling and isolation to protect entangled entities from decoherence by random interactions. Here we show that the opposite strategy—promoting random interactions—can help generate and preserve entanglement. We use optical quantum non-demolition measurement to produce entanglement in a hot alkali vapor, in a regime dominated by random spin-exchange collisions. We use Bayesian statistics and spin-squeezing inequalities to show that at least 1.52(4) × 1013 of the 5.32(12) × 1013 participating atoms enter into singlet-type entangled states, which persist for tens of spin-thermalization times and span thousands of times the nearest-neighbor distance. The results show that high temperatures and strong random interactions need not destroy many-body quantum coherence, that collective measurement can produce very complex entangled states, and that the hot, strongly-interacting media now in use for extreme atomic sensing are well suited for sensing beyond the standard quantum limit.
Scale and information-processing thresholds in Holocene social evolution
Authors: Shin Jaeweon , Price Michael Holton , Wolpert David H. , Shimao Hajime , Tracey Brendan , Kohler Timothy A.
Published: May 2020

Throughout the Holocene, societies developed additional layers of administration and more information-rich instruments for managing and recording transactions and events as they grew in population and territory. Yet, while such increases seem inevitable, they are not. Here we use the Seshat database to investigate the development of hundreds of polities, from multiple continents, over thousands of years. We find that sociopolitical development is dominated first by growth in polity scale, then by improvements in information processing and economic systems, and then by further increases in scale. We thus define a Scale Threshold for societies, beyond which growth in information processing becomes paramount, and an Information Threshold, which once crossed facilitates additional growth in scale. Polities diverge in socio-political features below the Information Threshold, but reconverge beyond it. We suggest an explanation for the evolutionary divergence between Old and New World polities based on phased growth in scale and information processing. We also suggest a mechanism to help explain social collapses with no evident external causes.
The native ORAI channel trio underlies the diversity of Ca2+ signaling events
Authors: Yoast Ryan E. , Emrich Scott M. , Zhang Xuexin , Xin Ping , Johnson Martin T. , Fike Adam J. , Walter Vonn , Hempel Nadine , Yule David I. , Sneyd James , Gill Donald L. , Trebak Mohamed
Published: May 2020

The essential role of ORAI1 channels in receptor-evoked Ca2+ signaling is well understood, yet little is known about the physiological activation of the ORAI channel trio natively expressed in all cells. The roles of ORAI2 and ORAI3 have remained obscure. We show that ORAI2 and ORAI3 channels play a critical role in mediating the regenerative Ca2+ oscillations induced by physiological receptor activation, yet ORAI1 is dispensable in generation of oscillations. We reveal that ORAI2 and ORAI3 channels multimerize with ORAI1 to expand the range of sensitivity of receptor-activated Ca2+ signals, reflecting their enhanced basal STIM1-binding and heightened Ca2+-dependent inactivation. This broadened bandwidth of Ca2+ influx is translated by cells into differential activation of NFAT1 and NFAT4 isoforms. Our results uncover a long-sought role for ORAI2 and ORAI3, revealing an intricate control mechanism whereby heteromerization of ORAI channels mediates graded Ca2+ signals that extend the agonist-sensitivity to fine-tune transcriptional control.
Plasma membrane H+-ATPases sustain pollen tube growth and fertilization
Authors: Hoffmann Robert D. , Portes Maria Teresa , Olsen Lene Irene , Damineli Daniel Santa Cruz , Hayashi Maki , Nunes Custódio O. , Pedersen Jesper T. , Lima Pedro T. , Campos Cláudia , Feijó José A. , Palmgren Michael
Published: May 2020

Pollen tubes are highly polarized tip-growing cells that depend on cytosolic pH gradients for signaling and growth. Autoinhibited plasma membrane proton (H+) ATPases (AHAs) have been proposed to energize pollen tube growth and underlie cell polarity, however, mechanistic evidence for this is lacking. Here we report that the combined loss ofAHA6, AHA8, andAHA9inArabidopsis thalianadelays pollen germination and causes pollen tube growth defects, leading to drastically reduced fertility. Pollen tubes ofahamutants had reduced extracellular proton (H+) and anion fluxes, reduced cytosolic pH, reduced tip-to-shank proton gradients, and defects in actin organization. Furthermore, mutant pollen tubes had less negative membrane potentials, substantiating a mechanistic role for AHAs in pollen tube growth through plasma membrane hyperpolarization. Our findings define AHAs as energy transducers that sustain the ionic circuit defining the spatial and temporal profiles of cytosolic pH, thereby controlling downstream pH-dependent mechanisms essential for pollen tube elongation, and thus plant fertility.
Ecology and allometry predict the evolution of avian developmental durations
Authors: Cooney Christopher R. , Sheard Catherine , Clark Andrew D. , Healy Susan D. , Liker András , Street Sally E. , Troisi Camille A. , Thomas Gavin H. , Székely Tamás , Hemmings Nicola , Wright Alison E.
Published: May 2020

The duration of the developmental period represents a fundamental axis of life-history variation, yet broad insights regarding the drivers of this diversity are currently lacking. Here, we test mechanistic and ecological explanations for the evolution of developmental duration using embryological data and information on incubation and fledging for 3096 avian species. Developmental phases associated primarily with growth are the longest and most variable, consistent with a role for allometric constraint in determining the duration of development. In addition, developmental durations retain a strong imprint of deep evolutionary history and body size differences among species explain less variation than previously thought. Finally, we reveal ecological correlates of developmental durations, including variables associated with the relative safety of the developmental environment and pressures of breeding phenology. Overall, our results provide broad-scale insight into the relative importance of mechanistic, ecological and evolutionary constraints in shaping the diversification of this key life-history trait.
Hopfions emerge in ferroelectrics
Authors: Luk’yanchuk I. , Tikhonov Y. , Razumnaya A. , Vinokur V. M.
Published: May 2020

Paradigmatic knotted solitons, Hopfions, that are characterized by topological Hopf invariant, attract an intense attention in the diverse areas of physics ranging from high-energy physics, cosmology and astrophysics to biology, magneto- and hydrodynamics and condensed matter physics. Yet, while being of broad interest, they remain elusive and under-explored. Here we demonstrate that Hopfions emerge as a basic configuration of polarization field in confined ferroelectric nanoparticles. Our findings establish that Hopfions are of fundamental importance for the electromagnetic behavior of the nanocomposits and can result in advanced functionalities of these materials.
Ballistic supercavitating nanoparticles driven by single Gaussian beam optical pushing and pulling forces
Authors: Lee Eungkyu , Huang Dezhao , Luo Tengfei
Published: May 2020

Directed high-speed motion of nanoscale objects in fluids can have a wide range of applications like molecular machinery, nano robotics, and material assembly. Here, we report ballistic plasmonic Au nanoparticle (NP) swimmers with unprecedented speeds (~336,000 μm s−1) realized by not only optical pushing but also pulling forces from a single Gaussian laser beam. Both the optical pulling and high speeds are made possible by a unique NP-laser interaction. The Au NP excited by the laser at the surface plasmon resonance peak can generate a nanoscale bubble, which can encapsulate the NP (i.e., supercavitation) to create a virtually frictionless environment for it to move, like the Leidenfrost effect. Certain NP-in-bubble configurations can lead to the optical pulling of NP against the photon stream. The demonstrated ultra-fast, light-driven NP movement may benefit a wide range of nano- and bio-applications and provide new insights to the field of optical pulling force.
Flexible and stretchable metal oxide nanofiber networks for multimodal and monolithically integrated wearable electronics
Authors: Wang Binghao , Thukral Anish , Xie Zhaoqian , Liu Limei , Zhang Xinan , Huang Wei , Yu Xinge , Yu Cunjiang , Marks Tobin J. , Facchetti Antonio
Published: May 2020

Fiber-based electronics enabling lightweight and mechanically flexible/stretchable functions are desirable for numerous e-textile/e-skin optoelectronic applications. These wearable devices require low-cost manufacturing, high reliability, multifunctionality and long-term stability. Here, we report the preparation of representative classes of 3D-inorganic nanofiber network (FN) films by a blow-spinning technique, including semiconducting indium-gallium-zinc oxide (IGZO) and copper oxide, as well as conducting indium-tin oxide and copper metal. Specifically, thin-film transistors based on IGZO FN exhibit negligible performance degradation after one thousand bending cycles and exceptional room-temperature gas sensing performance. Owing to their great stretchability, these metal oxide FNs can be laminated/embedded on/into elastomers, yielding multifunctional single-sensing resistors as well as fully monolithically integrated e-skin devices. These can detect and differentiate multiple stimuli including analytes, light, strain, pressure, temperature, humidity, body movement, and respiratory functions. All of these FN-based devices exhibit excellent sensitivity, response time, and detection limits, making them promising candidates for versatile wearable electronics.
Relaxation and revival of quasiparticles injected in an interacting quantum Hall liquid
Authors: Rodriguez R. H. , Parmentier F. D. , Ferraro D. , Roulleau P. , Gennser U. , Cavanna A. , Sassetti M. , Portier F. , Mailly D. , Roche P.
Published: May 2020

The one-dimensional, chiral edge channels of the quantum Hall effect are a promising platform in which to implement electron quantum optics experiments; however, Coulomb interactions between edge channels are a major source of decoherence and energy relaxation. It is therefore of large interest to understand the range and limitations of the simple quantum electron optics picture. Here we confirm experimentally for the first time the predicted relaxation and revival of electrons injected at finite energy into an edge channel. The observed decay of the injected electrons is reproduced theoretically within a Tomonaga-Luttinger liquid framework, including an important dissipation towards external degrees of freedom. This gives us a quantitative empirical understanding of the strength of the interaction and the dissipation.
Author Correction: Record thermopower found in an IrMn-based spintronic stack
Authors: Tu Sa , Ziman Timothy , Yu Guoqiang , Wan Caihua , Hu Junfeng , Wu Hao , Wang Hanchen , Liu Mengchao , Liu Chuanpu , Guo Chenyang , Zhang Jianyu , Cabero Z. Marco A. , Zhang Youguang , Gao Peng , Liu Song , Yu Dapeng , Han Xiufeng , Hallsteinsen Ingrid , Gilbert Dustin A. , Matsuo Mamoru , Ohnuma Yuichi , Wölfle Peter , Wang Kang L. , Ansermet Jean-Philippe , Maekawa Sadamichi , Yu Haiming
Published: May 2020

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Anomalous Hall effect, magneto-optical properties, and nonlinear optical properties of twisted graphene systems
Authors: Liu Jianpeng , Dai Xi
Published: May 2020

We study the anomalous Hall effect, magneto-optical properties, and nonlinear optical properties of twisted bilayer graphene aligned with hexagonal boron nitride substrate, as well as twisted double bilayer graphene systems. We show that non-vanishing valley polarizations in twisted graphene systems would give rise to the anomalous Hall effect, which can be tuned by in-plane magnetic fields. The valley polarized states are also associated with giant Faraday and Kerr rotations in the terahertz frequency regime. Moreover, we propose that the twisted graphene systems exhibit colossal nonlinear optical responses by virtue of the inversion-symmetry breaking, the small bandwidth, and the small excitation gaps of the systems. In twisted double bilayer graphene, we find that certain components of the nonlinear photo-conductivity tensor are directly proportional to the orbital magnetization of the system, which would exhibit remarkable hysteresis behavior in response to perpendicular magnetic fields.
Quantum classifier with tailored quantum kernel
Authors: Blank Carsten , Park Daniel K. , Rhee June-Koo Kevin , Petruccione Francesco
Published: May 2020

Kernel methods have a wide spectrum of applications in machine learning. Recently, a link between quantum computing and kernel theory has been formally established, opening up opportunities for quantum techniques to enhance various existing machine-learning methods. We present a distance-based quantum classifier whose kernel is based on the quantum state fidelity between training and test data. The quantum kernel can be tailored systematically with a quantum circuit to raise the kernel to an arbitrary power and to assign arbitrary weights to each training data. Given a specific input state, our protocol calculates the weighted power sum of fidelities of quantum data in quantum parallel via a swap-test circuit followed by two single-qubit measurements, requiring only a constant number of repetitions regardless of the number of data. We also show that our classifier is equivalent to measuring the expectation value of a Helstrom operator, from which the well-known optimal quantum state discrimination can be derived. We demonstrate the performance of our classifier via classical simulations with a realistic noise model and proof-of-principle experiments using the IBM quantum cloud platform.
Ab Initio and Theoretical Study on Electron Transport through Polyene Junctions in between Carbon Nanotube Leads of Various Cuts
Authors: Chen Yiing-Rei , Lin Ming-Kuan , Chan Dun-Hao , Lin Kuan-Bo , Kaun Chao-Cheng
Published: May 2020

In this study we look into the interference effect in multi-thread molecular junctions in between carbon-nanotube (CNT) electrodes of assorted edges. From the tube end into the tube bulk of selected CNTs, we investigate surface Green’s function and layer-by-layer local density of states (LDOS), and find that both the cross-cut and the angled-cut armchair CNTs exhibit 3-layer-cycled LDOS oscillations. Moreover, the angled-cut armchair CNTs, which possess a zigzag rim at the cut, exhibit not only the oscillations, but also edge state component that decays into the tube bulk. In the case of cross-cut zigzag CNTs, the LDOS shows no sign of oscillations, but prominent singularity feature due to edge states. With these cut CNTs as leads, we study the single-polyene and two-polyene molecular junctions via both ab initio and tight-binding model approaches. While the interference effect between transport channels is manifested through our results, we also differentiate the contributions towards transmission from the bulk states and the edge states, by understanding the difference in the Green’s functions obtained from direct integration method and iterative method, separately.
Nonlinear neural network dynamics accounts for human confidence in a sequence of perceptual decisions
Authors: Berlemont Kevin , Martin Jean-Rémy , Sackur Jérôme , Nadal Jean-Pierre
Published: May 2020

Electrophysiological recordings during perceptual decision tasks in monkeys suggest that the degree of confidence in a decision is based on a simple neural signal produced by the neural decision process. Attractor neural networks provide an appropriate biophysical modeling framework, and account for the experimental results very well. However, it remains unclear whether attractor neural networks can account for confidence reports in humans. We present the results from an experiment in which participants are asked to perform an orientation discrimination task, followed by a confidence judgment. Here we show that an attractor neural network model quantitatively reproduces, for each participant, the relations between accuracy, response times and confidence. We show that the attractor neural network also accounts for confidence-specific sequential effects observed in the experiment (participants are faster on trials following high confidence trials). Remarkably, this is obtained as an inevitable outcome of the network dynamics, without any feedback specific to the previous decision (that would result in, e.g., a change in the model parameters before the onset of the next trial). Our results thus suggest that a metacognitive process such as confidence in one’s decision is linked to the intrinsically nonlinear dynamics of the decision-making neural network.
Hierarchical phononic crystals for filtering multiple target frequencies of ultrasound
Authors: Lee Ki Yong , Jeon Wonju
Published: May 2020

Hierarchically structured phononic crystals are proposed for filtering multiple frequency bands. The advantages of using structural hierarchy come from its multiscale periodicity and the increased number of controllable parameters, which contribute to open multiple bandgaps in broadband frequency ranges and adjust the positions of those bandgaps. By deriving a transfer-matrix-based theoretical formula, hierarchical phononic crystals are designed that filter the frequency bands for randomly selected frequencies in the ultrasonic range of 20 kHz to 10 MHz. Their wave-filtering capability is demonstrated by using numerical simulations with consideration of material loss. By comparing the transmittance spectra of the hierarchical phononic crystals with those of conventional ones, the structural hierarchy of the former is shown to be advantageous in filtering multiple frequency bands.
3DI: A novel ion composition and three-dimensional velocity analyzer for the topside ionosphere
Authors: Ogasawara Keiichi , George Don E. , Goldstein Jerry , Hwang Kyoung-Joo , Nishimura Yukitoshi , Ruggles David A. , Stange Jason L.
Published: May 2020

A new ion composition and three-dimensional velocity analyzer, 3-Dimensional ion velocity and mass Imager (3DI), measures 3D velocity distribution functions (VDFs) for each major ion species in Earth’s topside ionosphere. The 3DI instrument is composed of a miniaturized electrostatic analyzer (ESA) and a deflector, backed by a static, magnet-based, mass spectrometer. We have developed a micro-pixel read-out anode technique that significantly saves power in the particle detection system, and integrated it into an imaging microchannel plate (MCP). We tested the ESA and deflector, magnet-based mass spectrometer, and anode in the laboratory to demonstrate the 3DI prototype’s performance. We have applied numerical calculations to evaluate and discuss 3DI’s performance and dynamic range. Due to complexities associated with imaging 3D distribution functions during fast spacecraft motion, we also discuss the operation strategy for 3DI to capture and resolve the VDF within the field of view. Once applied to flight investigations, the 3DI observations will be extremely useful in identifying ionosphere composition, mass-dependent ion transport such as upflows, and mass-dependent ion heating. Furthermore, the precise measurement of non-thermal plasma VDFs provides information to improve ionospheric environment modeling and ground-based radar observations.
Controlled Structure and Growth Mechanism behind Hydrothermal Growth of TiO2 Nanorods
Authors: Prathan Aschariya , Sanglao Jongrak , Wang Tao , Bhoomanee Chawalit , Ruankham Pipat , Gardchareon Atcharawon , Wongratanaphisan Duangmanee
Published: May 2020

Fabrication of uniform vertically-aligned titanium dioxide nanorods (TiO2 NRs) was achieved by hydrothermal growth on a fluorine-doped tin oxide (FTO) glass substrate. The substrate was coated by a TiO2 seed layer composed of titanium (IV) butoxide (TBO) as a precursor in an HCl solution. To reduce the amount of toxic substances used in this work, a minimal amount of HCl was used. On a larger scale, this method would require less precursor and therefore be a cost-savings. The aim of the present work is to achieve high crystalline orientations of TiO2 NRs for low quantities of both TBO precursor and HCl solutions. Results showed that the 0.7% TBO TiO2 NRs after 1.5 h of hydrothermal treatment exhibited the optimal crystalline orientation along [001] while the (002) plane is the dominant facet. The results demonstrate high transmittance of visible light and well-formed crystalline structures that offer a fast electron pathway along the length of the TiO2 NRs with less grain boundaries. Lastly, TiO2 NRs and their growth mechanism are discussed. This work offers a promising hydrothermal method for growing well-aligned TiO2 single-crystal NRs that can be employed in solar cell applications.
Genetic population structure of invasive raccoons (Procyon lotor) in Hokkaido, Japan: Unique phenomenon caused by pet escape or abandonment
Authors: Okuyama Minami W. , Shimozuru Michito , Nakai Mariko , Yamaguchi Emi , Fujii Kei , Shimada Ken-ichiro , Ikeda Tohru , Tsubota Toshio
Published: May 2020

Phylogeographic studies can resolve relationships between genetic population structure of organisms and geographical distributions. Raccoons have become feral in Japan, and in Hokkaido island, they have been rapidly increasing in number and spreading since the 1970s. We analyzed mitochondrial (mtDNA) and microsatellite DNA to understand the current phylogenetic distribution and invasive founder events. Overall, Hokkaido raccoons maintained high genetic diversity (i.e., the level of heterozygosity was comparable to the original habitat, North America). Based on mtDNA distribution and microsatellite diversity, Hokkaido raccoons were divided into six management units. However, mtDNA haplotype distributions and genetic structures based on microsatellites did not always correspond to each other (e.g., two geographically and genetically separated populations showed similar mtDNA distributions). In addition, a high degree of genetic admixture was observed in every unit, and the degree of genetic differentiation was low even between regions separated by long distances. Compared with other countries in Europe where genetic distribution of introduced raccoons is more clearly structured, the current results represent a unique and complex phenomenon of pet escape/abandonment in Hokkaido: i.e., genetically related colonies were introduced into multiple regions as founder events, resulting in the current state in which raccoons are not clearly genetically differentiated even 40 years after introduction.
Long-term sediment decline causes ongoing shrinkage of the Mekong megadelta, Vietnam
Authors: Tamura Toru , Nguyen Van Lap , Ta Thi Kim Oanh , Bateman Mark D. , Gugliotta Marcello , Anthony Edward J. , Nakashima Rei , Saito Yoshiki
Published: May 2020

Since the 1990s the Mekong River delta has suffered a large decline in sediment supply causing coastal erosion, following catchment disturbance through hydropower dam construction and sand extraction. However, our new geological reconstruction of 2500-years of delta shoreline changes show that serious coastal erosion actually started much earlier. Data shows the sandy coast bounding river mouths accreted consistently at a rate of +2 to +4 km2/year. In contrast, we identified a variable accretion rate of the muddy deltaic protrusion at Camau; it was < +1 km2/year before 1400 years ago but increased drastically around 600 years ago, forming the entire Camau Peninsula. This high level of mud supply had sharply declined by the early 20th century after a vast canal network was built on the delta. Since then the Peninsula has been eroding, promoted by the conjunction of mud sequestration in the delta plain driven by expansion of rice cultivation, and hysteresis of long-term muddy sedimentation that left the protrusion exposed to wave erosion. Natural mitigation would require substantial increases in sediment supply well above the pre-1990s levels.
The geometry as an eyed fish feels it in spontaneous and rewarded spatial reorientation tasks
Authors: Sovrano Valeria Anna , Baratti Greta , Potrich Davide , Bertolucci Cristiano
Published: May 2020

Disoriented human beings and animals, the latter both sighted and blind, are able to use spatial geometric information (metric and sense properties) to guide their reorientation behaviour in a rectangular environment. Here we aimed to investigate reorientation spatial skills in three fish species (Danio rerio, Xenotoca eiseni, Carassius auratus) in an attempt to discover the possible involvement of extra-visual senses during geometric navigation. We observed the fish’s behaviour under different experimental procedures (spontaneous social cued task and rewarded exit task), providing them different temporal opportunities to experience the environmental shape (no experience, short and prolonged experience). Results showed that by using spontaneous social cued memory tasks, fishes were not able to take advantage of extra-visual senses to encode the spatial geometry, neither allowing them short time-periods of environmental exploration. Contrariwise, by using a reference memory procedure, during the rewarded exit tasks, thus providing a prolonged extra-visual experience, fishes solved the geometric task, showing also differences in terms of learning times among species.
Statistical characterization of urban CO2 emission signals observed by commercial airliner measurements
Authors: Umezawa Taku , Matsueda Hidekazu , Oda Tomohiro , Higuchi Kaz , Sawa Yousuke , Machida Toshinobu , Niwa Yosuke , Maksyutov Shamil
Published: May 2020

Cities are responsible for the largest anthropogenic CO2 emissions and are key to effective emission reduction strategies. Urban CO2 emissions estimated from vertical atmospheric measurements can contribute to an independent quantification of the reporting of national emissions and will thus have political implications. We analyzed vertical atmospheric CO2 mole fraction data obtained onboard commercial aircraft in proximity to 36 airports worldwide, as part of the Comprehensive Observation Network for Trace gases by Airliners (CONTRAIL) program. At many airports, we observed significant flight-to-flight variations of CO2 enhancements downwind of neighboring cities, providing advective fingerprints of city CO2 emissions. Observed CO2 variability increased with decreasing altitude, the magnitude of which varied from city to city. We found that the magnitude of CO2 variability near the ground (~1 km altitude) at an airport was correlated with the intensity of CO2 emissions from a nearby city. Our study has demonstrated the usefulness of commercial aircraft data for city-scale anthropogenic CO2 emission studies.
Shared and Independent Genetic Basis of Resistance to Bt Toxin Cry2Ab in Two Strains of Pink Bollworm
Authors: Fabrick Jeffrey A. , LeRoy Dannialle M. , Unnithan Gopalan C. , Yelich Alex J. , Carrière Yves , Li Xianchun , Tabashnik Bruce E.
Published: May 2020

Evolution of pest resistance threatens the benefits of crops genetically engineered to produce insecticidal proteins from Bacillus thuringiensis (Bt). Field populations of the pink bollworm (Pectinophora gossypiella), a global pest of cotton, have evolved practical resistance to transgenic cotton producing Bt toxin Cry2Ab in India, but not in the United States. Previous results show that recessive mutations disrupting an autosomal ATP-binding cassette gene (PgABCA2) are associated with pink bollworm resistance to Cry2Ab in field-selected populations from India and in one lab-selected strain from the United States (Bt4-R2). Here we discovered that an independently derived, lab-selected Cry2Ab-resistant pink bollworm strain from the United States (BX-R) also harbors mutations that disrupt PgABCA2. Premature stop codons introduced by mis-splicing of PgABCA2 pre-mRNA were prevalent in field-selected larvae from India and in both lab-selected strains. The most common mutation in field-selected larvae from India was also detected in both lab-selected strains. Results from interstrain crosses indicate BX-R has at least one additional mechanism of resistance to Cry2Ab that does not involve PgABCA2 and is not completely recessive or autosomal. We conclude that recessive mutations disrupting PgABCA2 are the primary, but not the only, mechanism of resistance to Cry2Ab in pink bollworm.
Quantum driven proton diffusion in brucite-like minerals under high pressure
Authors: Schaack Sofiane , Depondt Philippe , Huppert Simon , Finocchi Fabio
Published: May 2020

Transport of hydrogen in hydrous minerals under high pressure is a key step for the water cycle within the Earth interior. Brucite Mg(OH)2 is one of the simplest minerals containing hydroxyl groups and is believed to decompose under the geological condition of the deep Earth’s mantle. In the present study, we investigate the proton diffusion in brucite under high pressure, which results from a complex interplay between two processes: the O–H reorientations motion around the c axis and O–H covalent bond dissociations. First-principle path-integral molecular dynamics simulations reveal that the increasing pressure tends to lock the former motion, while, in contrast, it activates the latter which is mainly triggered by nuclear quantum effects. These two competing effects therefore give rise to a pressure sweet spot for proton diffusion within the mineral. In brucite Mg(OH)2, proton diffusion reaches a maximum for pressures close to 70GPa, while the structurally similar portlandite Ca(OH)2 never shows proton diffusion within the pressure range and time scale that we explored. We analyze the different behavior of brucite and portlandite, which might constitute two prototypes for other minerals with same structure.
Circulating and tumor-infiltrating arginase 1-expressing cells in gastric adenocarcinoma patients were mainly immature and monocytic Myeloid-derived suppressor cells
Authors: Ren WeiHong , Zhang XuRan , Li WenBo , Feng Qian , Feng HuiJie , Tong Yan , Rong Hao , Wang Wei , Zhang Dai , Zhang ZhenQiang , Tu ShiChun
Published: May 2020

Myeloid-derived suppressor cells (MDSCs) are a group of heterogeneous cells derived from immature myeloid cells (IMCs). MDSCs are known to play important roles in tumor immune evasion. While we know that there are a large number of circulating and tumor-infiltrating MDSCs existing in gastric cancer (GC) patients, the phenotypic characteristics and arginase 1 (ARG1) expression levels of these MDSCs remain very unclear. In our study, flow cytometric analysis of circulating MDSCs from 20 gastric adenocarcinoma (GAC) patients found that ≥80% ARG1-expressing MDSCs were mainly early-stage MDSCs (HLA-DR−CD33+CD14−CD15−MDSCs). In addition, our investigation showed that tumor-infiltrating MDSCs from 6 GAC patients consisted of >35% ARG1-expressing naïve MDSCs (HLA-DR−CD33−CD11b−CD14−CD15−MDSCs), >15% early-stage MDSCs and >40% monocytic MDSCs (HLA-DR−CD14+MDSCs). This preliminary study describes the phenotypic characteristics and ARG1 expression levels of MDSCs from GAC patients and shows that circulating and tumor-infiltrating ARG1-expressing cells were mainly immature and monocytic MDSCs, which provides information to better understand the mechanisms that allow gastric cancer cells to evade the immune system.
Generation of Pseudo-CT using High-Degree Polynomial Regression on Dual-Contrast Pelvic MRI Data
Authors: Leu Samuel C. , Huang Zhibin , Lin Ziwei
Published: May 2020

Increasing interests in using magnetic resonance imaging only in radiation therapy require methods for predicting the computed tomography numbers from MRI data. Here we propose a simple voxel method to generate the pseudo-CT (pCT) image using dual-contrast pelvic MRI data. The method is first trained with the CT data and dual-contrast MRI data (two sets of MRI with different sequences) of multiple patients, where the anatomical structures in the images after deformable image registration are segmented into several regions, and after MRI intensity normalizations a regression analysis is used to determine a two-variable polynomial function for each region to relate a voxel’s two MRI intensity values to its CT number. We first evaluate the accuracy via the Hounsfield unit (HU) difference between the pseudo-CT and reference-CT (rCT) images and obtain the average mean absolute error as 40.3 ± 2.9 HU from leave-one-out-cross-validation (LOOCV) across all six patients, which is better than most previous results and comparable to another study using the more complicated atlas-based method. We also perform a dosimetric evaluation of the treatment plans based on pCT and rCT images and find the average passing rate within 2% dose difference to be 95.4% in point-to-point dose comparisons. Therefore, our method shows encouraging results in predicting the CT numbers. This polynomial method needs less computer storage than the interpolation method and can be readily extended to the case of more than two MRI sequences.
Methodology for the identification of small molecule inhibitors of the Fanconi Anaemia ubiquitin E3 ligase complex
Authors: Sharp Michael F. , Murphy Vince J. , Twest Sylvie Van , Tan Winnie , Lui Jennii , Simpson Kaylene J. , Deans Andrew J. , Crismani Wayne
Published: May 2020

DNA inter-strand crosslinks (ICLs) threaten genomic stability by creating a physical barrier to DNA replication and transcription. ICLs can be caused by endogenous reactive metabolites or from chemotherapeutics. ICL repair in humans depends heavily on the Fanconi Anaemia (FA) pathway. A key signalling step of the FA pathway is the mono-ubiquitination of Fanconi Anaemia Complementation Group D2 (FANCD2), which is achieved by the multi-subunit E3 ligase complex. FANCD2 mono-ubiquitination leads to the recruitment of DNA repair proteins to the site of the ICL. The loss of FANCD2 mono-ubiquitination is a common clinical feature of FA patient cells. Therefore, molecules that restore FANCD2 mono-ubiquitination could lead to a potential drug for the management of FA. On the other hand, in some cancers, FANCD2 mono-ubiquitination has been shown to be essential for cell survival. Therefore, inhibition of FANCD2 mono-ubiquitination represents a possible therapeutic strategy for cancer specific killing. We transferred an 11-protein FANCD2 mono-ubiquitination assay to a high-throughput format. We screened 9,067 compounds for both activation and inhibition of the E3 ligase complex. The use of orthogonal assays revealed that candidate compounds acted via non-specific mechanisms. However, our high-throughput biochemical assays demonstrate the feasibility of using sophisticated and robust biochemistry to screen for small molecules that modulate a key step in the FA pathway. The future identification of FA pathway modulators is anticipated to guide future medicinal chemistry projects with drug leads for human disease.
Development of Small Molecule MEIS Inhibitors that modulate HSC activity
Authors: Turan Raife Dilek , Albayrak Esra , Uslu Merve , Siyah Pinar , Alyazici Lamia Yazgi , Kalkan Batuhan Mert , Aslan Galip Servet , Yucel Dogacan , Aksoz Merve , Tuysuz Emre Can , Meric Neslihan , Durdagi Serdar , Gulbas Zafer , Kocabas Fatih
Published: May 2020

Meis1, which belongs to TALE-type class of homeobox gene family, appeared as one of the key regulators of hematopoietic stem cell (HSC) self-renewal and a potential therapeutical target. However, small molecule inhibitors of MEIS1 remained unknown. This led us to develop inhibitors of MEIS1 that could modulate HSC activity. To this end, we have established a library of relevant homeobox family inhibitors and developed a high-throughputin silicoscreening strategy against homeodomain of MEIS proteins using the AutoDock Vina and PaDEL-ADV platform. We have screened over a million druggable small moleculesin silicoand selected putative MEIS inhibitors (MEISi) with no predicted cytotoxicity or cardiotoxicity. This was followed byin vitrovalidation of putative MEIS inhibitors using MEIS dependent luciferase reporter assays and analysis in theex vivoHSC assays. We have shown that small molecules named MEISi-1 and MEISi-2 significantly inhibit MEIS-luciferase reportersin vitroand induce murine (LSKCD34l°wcells) and human (CD34+, CD133+, and ALDHhicells) HSC self-renewalex vivo. In addition, inhibition of MEIS proteins results in downregulation ofMeis1and MEIS1 target gene expression including Hif-1α, Hif-2α and HSC quiescence modulators. MEIS inhibitors are effectivein vivoas evident by induced HSC content in the murine bone marrow and downregulation of expression of MEIS target genes. These studies warrant identification of first-in-class MEIS inhibitors as potential pharmaceuticals to be utilized in modulation of HSC activity and bone marrow transplantation studies.
An automated data processing and analysis pipeline for transmembrane proteins in detergent solutions
Authors: Molodenskiy Dmitry S. , Mertens Haydyn D. T. , Svergun Dmitri I.
Published: May 2020

The application of small angle X-ray scattering (SAXS) to the structural characterization of transmembrane proteins (MPs) in detergent solutions has become a routine procedure at synchrotron BioSAXS beamlines around the world. SAXS provides overall parameters and low resolution shapes of solubilized MPs, but is also meaningfully employed in hybrid modeling procedures that combine scattering data with information provided by high-resolution techniques (eg. macromolecular crystallography, nuclear magnetic resonance and cryo-electron microscopy). Structural modeling of MPs from SAXS data is non-trivial, and the necessary computational procedures require further formalization and facilitation. We propose an automated pipeline integrated with the laboratory-information management system ISPyB, aimed at preliminary SAXS analysis and the first-step reconstruction of MPs in detergent solutions, in order to streamline high-throughput studies, especially at synchrotron beamlines. The pipeline queries an ISPyB database for available a priori information via dedicated services, estimates model-free SAXS parameters and generates preliminary models utilizing either ab initio, high-resolution-based, or mixed/hybrid methods. The results of the automated analysis can be inspected online using the standard ISPyB interface and the estimated modeling parameters may be utilized for further in-depth modeling beyond the pipeline. Examples of the pipeline results for the modelling of the tetrameric alpha-helical membrane channel Aquaporin0 and mechanosensitive channel T2, solubilized by n-Dodecyl β-D-maltoside are presented. We demonstrate how increasing the amount of a priori information improves model resolution and enables deeper insights into the molecular structure of protein-detergent complexes.
Effects of local hypothermia–rewarming on physiology, metabolism and inflammation of acutely injured human spinal cord
Authors: Gallagher Mathew J. , Hogg Florence R. A. , Kearney Siobhan , Kopp Marcel A. , Blex Christian , Serdani Leonarda , Sherwood Oliver , Schwab Jan M. , Zoumprouli Argyro , Papadopoulos Marios C. , Saadoun Samira
Published: May 2020

In five patients with acute, severe thoracic traumatic spinal cord injuries (TSCIs), American spinal injuries association Impairment Scale (AIS) grades A–C, we induced cord hypothermia (33 °C) then rewarming (37 °C). A pressure probe and a microdialysis catheter were placed intradurally at the injury site to monitor intraspinal pressure (ISP), spinal cord perfusion pressure (SCPP), tissue metabolism and inflammation. Cord hypothermia–rewarming, applied to awake patients, did not cause discomfort or neurological deterioration. Cooling did not affect cord physiology (ISP, SCPP), but markedly altered cord metabolism (increased glucose, lactate, lactate/pyruvate ratio (LPR), glutamate; decreased glycerol) and markedly reduced cord inflammation (reduced IL1β, IL8, MCP, MIP1α, MIP1β). Compared with pre-cooling baseline, rewarming was associated with significantly worse cord physiology (increased ICP, decreased SCPP), cord metabolism (increased lactate, LPR; decreased glucose, glycerol) and cord inflammation (increased IL1β, IL8, IL4, IL10, MCP, MIP1α). The study was terminated because three patients developed delayed wound infections. At 18-months, two patients improved and three stayed the same. We conclude that, after TSCI, hypothermia is potentially beneficial by reducing cord inflammation, though after rewarming these benefits are lost due to increases in cord swelling, ischemia and inflammation. We thus urge caution when using hypothermia–rewarming therapeutically in TSCI.
Pollinator divergence and pollination isolation between hybrids with different floral color and morphology in two sympatric Penstemon species
Authors: Cardona Juliana , Lara Carlos , Ornelas Juan Francisco
Published: May 2020

Differential visitation of pollinators due to divergent floral traits can lead to reproductive isolation via assortative pollen flow, which may ultimately be a driving force in plant speciation, particularly in areas of overlap. We evaluate the effects of pollinator behavioral responses to variation of intraspecific floral color and nectar rewards, on reproductive isolation between two hybrid flower color morphs (fuchsia and blue) and their parental species Penstemon roseus and P. gentianoides with a mixed-pollination system. We show that pollinators (bumblebees and hummingbirds) exhibit different behavioral responses to fuchsia and blue morphs, which could result from differential attraction or deterrence. In addition to differences in color (spectral reflectance), we found that plants with fuchsia flowers produced more and larger flowers, produced more nectar and were more visited by pollinators than those with blue flowers. These differences influenced the foraging behavior and effectiveness as pollinators of both bumblebees and hummingbirds, which contributed to reproductive isolation between the two hybrid flower color morphs and parental species. This study demonstrates how differentiation of pollination traits promotes the formation of hybrid zones leading to pollinator shifts and reproductive isolation. While phenotypic traits of fuchsia and red flowers might encourage more efficient hummingbird pollination in a mixed-pollination system, the costs of bumblebee pollination on plant reproduction could be the drivers for the repeated shifts from bumblebee- to hummingbird-mediated pollination.
Quantitative analysis of breast tumours aided by three-dimensional photoacoustic/ultrasound functional imaging
Authors: Yang Meng , Zhao Lingyi , Yang Fang , Wang Ming , Su Na , Zhao Chenyang , Gui Yang , Wei Yao , Zhang Rui , Li Jianchu , Han Tao , He Xujin , Zhu Lei , Wu Huanwen , Li Changhui , Jiang Yuxin
Published: May 2020

In this pilot study, we explored a quantitative method to analyse characteristics of breast tumours using 3D volumetric data obtained from a three-dimensional (3D) photoacoustic/ultrasound (PA/US) functional imaging system. Imaging results from 24 Asian patients with maximum tumour diameters less than 2 cm, including 8 benign tumours, 16 T1 stage invasive breast cancers (IBCs), and 22 normal breasts, were analysed. We found that the volumetric mean oxygenation saturation (SO2) in tumour regions of T1 stage IBCs was 7.7% lower than that of benign tumours (P = 0.016) and 3.9% lower than that of healthy breasts (P = 0.010). The volumetric mean SO2 in tumour surrounding regions of T1 stage IBCs was 4.9% lower than that of benign tumours (P = 0.009). For differentiating T1 stage IBCs and benign tumours, with a cut-off SO2 value of 78.2% inside tumours, we obtained a sensitivity of 100%, a specificity of 62.5%, and an AUC of 0.81; with a cut-off SO2 value of 77.9% in regions surrounding tumours, we obtained a sensitivity of 100%, a specificity of 75% and an AUC of 0.84. Our preliminary results demonstrate that 3D PA/US functional imaging has the potential to provide valuable quantitative physiological information that may be useful for the detection and evaluation of breast tumours.
An Extended Duration of the Pre-Operative Hospitalization is Associated with an Increased Risk of Healthcare-Associated Infections after Cardiac Surgery
Authors: Sulzgruber Patrick , Schnaubelt Sebastian , Koller Lorenz , Laufer Günther , Pilz Arnold , Kazem Niema , Winter Max-Paul , Steinlechner Barbara , Andreas Martin , Fleck Tatjana , Distelmaier Klaus , Goliasch Georg , Toma Aurel , Hengstenberg Christian , Niessner Alexander
Published: May 2020

Nosocomial infections are a common complication in clinical practice with major impact on surgical success and patient outcome. The probability of nosocomial infections is rapidly increasing during hospitalization. Therefore, we investigated the impact of a prolonged pre-operative hospital stay on the development of post-operative infection. Within this prospective observational study, 200 patients scheduled for elective cardiac surgery were enrolled. Patients were followed during hospital admission and screened for the development of nosocomial infection. Logistic regression analysis was used to assess the impact of a prolonged pre-operative hospital stay on the development of infection. A total of 195 patients were suitable for the final analysis. We found a strong and direct association of the duration of pre-operative hospital stay and the number of patients developing infection (+23.5%; p = 0.006). Additionally, the length of patients’ pre-operative hospital stay was independently associated with the development of post-operative nosocomial infection, with an adjusted OR per day of 1.38 (95%CI: 1.02–1.86; p = 0.036). A prolonged pre-operative hospital stay was significantly associated with the development of nosocomial infection after cardiac surgery. Those findings need to be considered in future clinical patient management in order to prevent unnecessary antibiotic use and potential harm to patients.