bluuebunny/crossref_metadata_2025_split huggingface dataset:
Implication of Tidal Forcing Effects on the Zonal Variation of Solstice Equatorial Plasma Bubbles
Authors: Chang Loren C. , Salinas Cornelius Csar Jude H. , Chiu Yi‐Chung , Jones McArthur , Rajesh P. K. , Chao Chi‐Kuang , Liu Jann‐Yenq , Lin Charles C. H. , Hsiao Tung‐Yuan 
Published: February 2021

AbstractEquatorial plasma bubbles (EPBs) are plasma depletions that can occur in the nighttime ionospheric F region, causing scintillation in satellite navigation and communications signals. Past research has shown that EPB occurrence rates are higher during the equinoxes in most longitude zones. An exception is over the central Pacific and African sectors, where EPB activity has been found to maximize during solstice. Tsunoda et al. (2015) hypothesized that the solstice maxima in these two sectors could be driven by a zonal wavenumber 2 atmospheric tide in the lower thermosphere. In this study, we utilize satellite observations to examine evidence of such a wave‐2 feature preconditioning the nighttime ionosphere to favor higher EPB growth rates over these two regions. We find the postsunset total electron content (TEC) observed by FORMOSAT‐3/COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) during boreal summer from 2007 to 2012 exhibits a wave‐2 zonal distribution, consistent with elevated vertical plasma gradients favorable for EPB formation. Numerical experiments are also carried out to determine whether such an ionospheric wave‐2 can be produced as a result of vertical coupling from atmospheric tides with zonal wavenumber 2 in the local time frame. We find that forcing from these tidal components produced increases in the Rayleigh‐Taylor growth rate over both sectors during solar maximum and minimum, as well as wave‐2 modulations on vertical ion drift, ion flux convergence, and nighttime TEC. Our results are consistent with the aforementioned hypothesis over both regions with vertical coupling effects from atmospheric tides preconditioning the nighttime ionosphere to favor higher EPB growth rates.
Temporal Evolution of Flux Rope/Tube Entanglement in 3‐D Hall MHD Simulations
Authors: Jia Ying‐Dong , Qi Yi , Lu San , Russell C. T. 
Published: February 2021

AbstractAt the Earth’s magnetopause, flux tubes observed by the Magnetospheric Multiscale (MMS) spacecraft in “entangled” pairs have been interpreted as a precursory stage to the formation of a new pair of flux tubes by magnetic reconnection, of which one reconnected tube joins the magnetosphere. Understanding the connectivity of these tubes before and after the entanglement is essential to understanding the transport of particles and energy between the magnetosphere and the solar wind. In this study, we use a three‐dimensional Hall Magnetohydrodynamics (MHD) model to simulate the interaction of two entangled flux tubes in the ambient plasma. Four types of interactions are simulated: Two types of magnetic field geometry (flux tube‐flux tube and flux rope‐flux rope) are tested separately, each under two different boundary conditions. With the boundary condition that drives the interaction with ambient flow, magnetic reconnection transforms the two tubes/ropes into new pairs. The process is performed under plasma conditions comparable to those of such events identified in recent MMS observations. The detailed three‐dimensional evolution is shown at representative stages, with key parameters shown across the entanglement interface. The shape of the central current sheet and evolution of magnetic field curvature are also discussed. Our study supports the feasibility of reconnection between entangled flux tubes, recognizes the importance of ambient plasma conditions for the completion of such processes, and quantifies how such structures evolve to modify the solar wind‐geomagnetic field interaction. In addition, this model is applicable to flux rope interactions in the solar corona.
Kinetic Modeling of Langmuir Probes in Space and Application to the MAVEN Langmuir Probe and Waves Instrument
Authors: Ergun R. E. , Andersson L. A. , Fowler C. M. , Thaller S. A. 
Published: February 2021

AbstractSelf‐consistent kinetic solutions from test‐particle simulations are used to improve the derivation of electron temperature (Te) and density (ne) from Langmuir probes in space. While Langmuir probes are well understood, the non‐ideal characteristics of space‐flight instruments can influence the accuracy of Te and ne and how they are derived. In particular, when in an ionosphere, spacecraft motion often causes a sensor wake and exposes its surface to oxidation. This work has two primary goals. We present kinetic solutions of general interest then apply our findings to the Langmuir Probe and Waves (LPW) instrument on the MAVEN satellite. Of general interest, (1) kinetic solutions show that mechanical mounting of a Langmuir probe sensor and controlling the potential of nearby surfaces is critical for accuracy. (2) An ion wake generated by the sensor can greatly modify how ne must be derived. (3) Interestingly, small voltage variations on the surface of the sensor do not significantly diminish the accuracy of Te and ne. (4) On the other hand, surface resistance on the sensor can appreciably disturb the derivation of Te. The LPW instrument is recalibrated with the aid of kinetic solutions and published results from laboratory experiments. The systematic uncertainty (as opposed to random variations) in Te is improved to as low as ±0.005 eV (±60 K) when ne > ∼3 × 104 cm−3. This recalibration leads to some of the most accurate measurements of Te made in space and can result in improved modeling of Mars' ionosphere.
Inferring the Subsurface Geometry and Strength of Slow‐Moving Landslides Using 3‐D Velocity Measurements From the NASA/JPL UAVSAR
Authors: Handwerger Alexander L. , Booth Adam M. , Huang Mong‐Han , Fielding Eric J. 
Published: February 2021

AbstractThe hazardous impact and erosive potential of slow‐moving landslides depends on landslide properties including velocity, size, and frequency of occurrence. However, constraints on size, in particular, subsurface geometry, are lacking because these types of landslides rarely fully evacuate material to create measurable hillslope scars. Here, we use pixel offset tracking with data from the NASA/JPL Uninhabited Aerial Vehicle Synthetic Aperture Radar to measure the three‐dimensional surface deformation of 134 slow‐moving landslides in the northern California Coast Ranges. We apply volume conservation to infer the actively deforming thickness, volume, geometric scaling, and frictional strength of each landslide. These landslides move at average rates between ∼0.1–2 m/yr and have active areas of ∼6.10 × 103–2.35 × 106 m2, inferred mean thicknesses of ∼1.1–25 m, and volumes of ∼7.01 × 103–9.75 × 106 m3. The best fit volume‐area geometric scaling exponent is γ ∼ 1.2–1.5, indicating that these landslides fall between typical soil and bedrock landslide scaling. A rollover in the scaling relationship suggests that the largest landslide complexes in our data set become large primarily by increasing in area rather than thickness. In addition, the slow‐moving landslides display scale‐dependent frictional strength, such that large landslide tend to be weaker than small landslides. This decrease in frictional strength with landslide size is likely because larger landslides are composed of higher proportions of weak material. Our work shows how state of the art remote sensing techniques can be used to better understand landslide processes and quantify their contribution to landscape evolution and hazards to human safety.
Analytical, Experimental, and Numerical Investigation of Partially Penetrating Barriers for Expanding Island Freshwater Lenses
Authors: Yan Min , Lu Chunhui , Werner Adrian D. , Luo Jian 
Published: February 2021

AbstractFreshwater lenses are of great importance in supporting both the vulnerable ecosystems of small‐to‐medium oceanic islands and the lives of local inhabitants. Recently, an engineering approach that embeds a low‐permeability, fully penetrating barrier along the shoreline was proposed and demonstrated under controlled conditions to be effective in enhancing island lens size. The current study extends that work by investigating the effect of partially penetrating barriers placed at the shoreline on both circular and strip island lenses, using: (1) sharp‐interface analytical solutions, (2) dispersive numerical modeling, and (3) sand tank experimentation. Analytical, experimental, and numerical results are in reasonable agreement in terms of the freshwater‐seawater interface. The findings indicate that partially penetrating barriers of sufficient depth (i.e., the freshwater depth in barrier from the fully penetrating barrier case) produce comparable results to fully penetrating barriers, and therefore, the former is more cost‐effectiveness. Moreover, the minimum barrier depth (i.e., the “critical depth”) required to obtain approximately the same lens as that achieved using the fully penetrating barrier is estimable from the analytical solution, as verified by laboratory experiments and numerical simulations. The sensitivity analysis based on the analytical solution indicates that a lower barrier permeability and a greater barrier thickness, which lead to a higher freshwater storage (as expected), require a larger critical depth. The guidance on the design of partially penetrating shoreline barriers arising from this research adds to existing engineering techniques for enhancing freshwater resources on circular and strip islands.
Ultrahigh-density spin-polarized hydrogen isotopes from the photodissociation of hydrogen halides: new applications for laser-ion acceleration, magnetometry, and polarized nuclear fusion
Authors: Spiliotis Alexandros K. , Xygkis Michalis , Koutrakis Michail E. , Tazes Konstantinos , Boulogiannis Gregoris K. , Kannis Chrysovalantis S. , Katsoprinakis Georgios E. , Sofikitis Dimitrios , Rakitzis T. Peter 
Published: February 2021

AbstractRecently, our group produced spin-polarized hydrogen (SPH) atoms at densities of at least 1019 cm−3 from the photodissociation of hydrogen halide molecules with circularly polarized UV light and measured them via magnetization-quantum beats with a pickup coil. These densities are approximately 7 orders of magnitude higher than those produced using conventional methods, opening up new fields of application, such as ultrafast magnetometry, the production of polarized MeV and GeV particle beams, such as electron beams with intensities approximately 104 higher than current sources, and the study of polarized nuclear fusion, for which the reaction cross sections of D–T and D–3He reactions are expected to increase by 50% for fully polarized nuclear spins. We review the production, detection, depolarization mechanisms, and potential applications of high-density SPH.
CHBP induces stronger immunosuppressive CD127+ M-MDSC via erythropoietin receptor
Authors: Li Jiawei , Tu Guowei , Zhang Weitao , Zhang Yi , Zhang Xuepeng , Qiu Yue , Wang Jiyan , Sun Tianle , Zhu Tongyu , Yang Cheng , Rong Ruiming 
Published: February 2021

AbstractErythropoietin (EPO) is not only an erythropoiesis hormone but also an immune-regulatory cytokine. The receptors of EPO (EPOR)2 and tissue-protective receptor (TPR), mediate EPO’s immune regulation. Our group firstly reported a non-erythropoietic peptide derivant of EPO, cyclic helix B peptide (CHBP), which could inhibit macrophages inflammation and dendritic cells (DCs) maturation. As a kind of innate immune regulatory cell, myeloid-derived suppressor cells (MDSCs) share a common myeloid progenitor with macrophages and DCs. In this study, we investigated the effects on MDSCs differentiation and immunosuppressive function via CHBP induction. CHBP promoted MDSCs differentiate toward M-MDSCs with enhanced immunosuppressive capability. Infusion of CHBP-induced M-MDSCs significantly prolonged murine skin allograft survival compared to its counterpart without CHBP stimulation. In addition, we found CHBP increased the proportion of CD11b+Ly6G−Ly6Chigh CD127+ M-MDSCs, which exerted a stronger immunosuppressive function compared to CD11b+Ly6G−Ly6Chigh CD127− M-MDSCs. In CHBP induced M-MDSCs, we found that EPOR downstream signal proteins Jak2 and STAT3 were upregulated, which had a strong relationship with MDSC function. In addition, CHBP upregulated GATA-binding protein 3 (GATA-3) protein translation level, which was an upstream signal of CD127 and regulator of STAT3. These effects of CHBP could be reversed if Epor was deficient. Our novel findings identified a new subset of M-MDSCs with better immunosuppressive capability, which was induced by the EPOR-mediated Jak2/GATA3/STAT3 pathway. These results are beneficial for CHBP clinical translation and MDSC cell therapy in the future.
Acute glucose influx-induced mitochondrial hyperpolarization inactivates myosin phosphatase as a novel mechanism of vascular smooth muscle contraction
Authors: Xu Jie , Yang Hongyan , Yang Lu , Wang Zhen , Qin Xinghua , Zhou Jiaheng , Dong Ling , Li Jia , Zhu Minsheng , Zhang Xing , Gao Feng 
Published: February 2021

AbstractIt is well-established that long-term exposure of the vasculature to metabolic disturbances leads to abnormal vascular tone, while the physiological regulation of vascular tone upon acute metabolic challenge remains unknown. Here, we found that acute glucose challenge induced transient increases in blood pressure and vascular constriction in humans and mice. Ex vivo study in isolated thoracic aortas from mice showed that glucose-induced vascular constriction is dependent on glucose oxidation in vascular smooth muscle cells. Specifically, mitochondrial membrane potential (ΔΨm), an essential component in glucose oxidation, was increased along with glucose influx and positively regulated vascular smooth muscle tone. Mechanistically, mitochondrial hyperpolarization inhibited the activity of myosin light chain phosphatase (MLCP) in a Ca2+-independent manner through activation of Rho-associated kinase, leading to cell contraction. However, ΔΨm regulated smooth muscle tone independently of the small G protein RhoA, a major regulator of Rho-associated kinase signaling. Furthermore, myosin phosphatase target subunit 1 (MYPT1) was found to be a key molecule in mediating MLCP activity regulated by ΔΨm. ΔΨm positively phosphorylated MYPT1, and either knockdown or knockout of MYPT1 abolished the effects of glucose in stimulating smooth muscle contraction. In addition, smooth muscle-specific Mypt1 knockout mice displayed blunted response to glucose challenge in blood pressure and vascular constriction and impaired clearance rate of circulating metabolites. These results suggested that glucose influx stimulates vascular smooth muscle contraction via mitochondrial hyperpolarization-inactivated myosin phosphatase, which represents a novel mechanism underlying vascular constriction and circulating metabolite clearance.
Identification of a bacteria-produced benzisoxazole with antibiotic activity against multi-drug resistant Acinetobacter baumannii
Authors: Deering Robert W. , Whalen Kristen E. , Alvarez Ivan , Daffinee Kathryn , Beganovic Maya , LaPlante Kerry L. , Kishore Shreya , Zhao Sijing , Cezairliyan Brent , Yu Shen , Rosario Margaret , Mincer Tracy J. , Rowley David C. 
Published: February 2021

AbstractThe emergence of multi-drug resistant pathogenic bacteria represents a serious and growing threat to national healthcare systems. Most pressing is an immediate need for the development of novel antibacterial agents to treat Gram-negative multi-drug resistant infections, including the opportunistic, hospital-derived pathogen,Acinetobacter baumannii. Herein we report a naturally occurring 1,2-benzisoxazole with minimum inhibitory concentrations as low as 6.25 μg ml−1against clinical strains of multi-drug resistantA. baumanniiand investigate its possible mechanisms of action. This molecule represents a new chemotype for antibacterial agents againstA. baumanniiand is easily accessed in two steps via de novo synthesis. In vitro testing of structural analogs suggest that the natural compound may already be optimized for activity against this pathogen. Our results demonstrate that supplementation of 4-hydroxybenzoate in minimal media was able to reverse 1,2-benzisoxazole’s antibacterial effects inA. baumannii. A search of metabolic pathways involving 4-hydroxybenzoate coupled with molecular modeling studies implicates two enzymes, chorismate pyruvate-lyase and 4-hydroxybenzoate octaprenyltransferase, as promising leads for the target of 3,6-dihydroxy-1,2-benzisoxazole.
A complete hierarchy for the pure state marginal problem in quantum mechanics
Authors: Yu Xiao-Dong , Simnacher Timo , Wyderka Nikolai , Nguyen H. Chau , Gühne Otfried 
Published: February 2021

AbstractClarifying the relation between the whole and its parts is crucial for many problems in science. In quantum mechanics, this question manifests itself in the quantum marginal problem, which asks whether there is a global pure quantum state for some given marginals. This problem arises in many contexts, ranging from quantum chemistry to entanglement theory and quantum error correcting codes. In this paper, we prove a correspondence of the marginal problem to the separability problem. Based on this, we describe a sequence of semidefinite programs which can decide whether some given marginals are compatible with some pure global quantum state. As an application, we prove that the existence of multiparticle absolutely maximally entangled states for a given dimension is equivalent to the separability of an explicitly given two-party quantum state. Finally, we show that the existence of quantum codes with given parameters can also be interpreted as a marginal problem, hence, our complete hierarchy can also be used.
Dual targeting of polyamine synthesis and uptake in diffuse intrinsic pontine gliomas
Authors: Khan Aaminah , Gamble Laura D. , Upton Dannielle H. , Ung Caitlin , Yu Denise M. T. , Ehteda Anahid , Pandher Ruby , Mayoh Chelsea , Hébert Steven , Jabado Nada , Kleinman Claudia L. , Burns Mark R. , Norris Murray D. , Haber Michelle , Tsoli Maria , Ziegler David S. 
Published: February 2021

AbstractDiffuse intrinsic pontine glioma (DIPG) is an incurable malignant childhood brain tumor, with no active systemic therapies and a 5-year survival of less than 1%. Polyamines are small organic polycations that are essential for DNA replication, translation and cell proliferation. Ornithine decarboxylase 1 (ODC1), the rate-limiting enzyme in polyamine synthesis, is irreversibly inhibited by difluoromethylornithine (DFMO). Herein we show that polyamine synthesis is upregulated in DIPG, leading to sensitivity to DFMO. DIPG cells compensate for ODC1 inhibition by upregulation of the polyamine transporter SLC3A2. Treatment with the polyamine transporter inhibitor AMXT 1501 reduces uptake of polyamines in DIPG cells, and co-administration of AMXT 1501 and DFMO leads to potent in vitro activity, and significant extension of survival in three aggressive DIPG orthotopic animal models. Collectively, these results demonstrate the potential of dual targeting of polyamine synthesis and uptake as a therapeutic strategy for incurable DIPG.
Efficacy in deceptive vocal exaggeration of human body size
Authors: Pisanski Katarzyna , Reby David 
Published: February 2021

AbstractHow can deceptive communication signals exist in an evolutionarily stable signalling system? To resolve this age-old honest signalling paradox, researchers must first establish whether deception benefits deceivers. However, while vocal exaggeration is widespread in the animal kingdom and assumably adaptive, its effectiveness in biasing listeners has not been established. Here, we show that human listeners can detect deceptive vocal signals produced by vocalisers who volitionally shift their voice frequencies to exaggerate or attenuate their perceived size. Listeners can also judge the relative heights of cheaters, whose deceptive signals retain reliable acoustic cues to interindividual height. Importantly, although vocal deception biases listeners’ absolute height judgments, listeners recalibrate their height assessments for vocalisers they correctly and concurrently identify as deceptive, particularly men judging men. Thus, while size exaggeration can fool listeners, benefiting the deceiver, its detection can reduce bias and mitigate costs for listeners, underscoring an unremitting arms-race between signallers and receivers in animal communication.
Automatic light-adjusting electrochromic device powered by perovskite solar cell
Authors: Ling Huan , Wu Jianchang , Su Fengyu , Tian Yanqing , Liu Yan Jun 
Published: February 2021

AbstractElectrochromic devices can modulate their light absorption under a small driving voltage, but the requirement for external electrical supplies causes response-lag. To address this problem, self-powered electrochromic devices have been studied recently. However, insensitivity to the surrounding light and unsatisfactory stability of electrochromic devices have hindered their critical applications. Herein, novel perovskite solar cell-powered all-in-one gel electrochromic devices have been assembled and studied in order to achieve automatic light adjustment. Two alkynyl-containing viologen derivatives are synthesized as electrochromic materials, the devices with very high stability (up to 70000 cycles) serves as the energy storage and smart window, while the perovskite solar cell with power-conversion-efficiency up to 18.3% serves as the light detector and power harvester. The combined devices can automatically switch between bleached and colored state to adjust light absorption with variable surrounding light intensity in real-time swiftly, which establish significant potentials for applications as modern all-day intelligent windows.
Persistence of self-reactive CD8+ T cells in the CNS requires TOX-dependent chromatin remodeling
Authors: Page Nicolas , Lemeille Sylvain , Vincenti Ilena , Klimek Bogna , Mariotte Alexandre , Wagner Ingrid , Di Liberto Giovanni , Kaye Jonathan , Merkler Doron 
Published: February 2021

AbstractSelf-reactive CD8+T cells are important mediators of progressive tissue damage in autoimmune diseases, but the molecular program underlying these cells’ functional adaptation is unclear. Here we characterize the transcriptional and epigenetic landscape of self-reactive CD8+T cells in a mouse model of protracted central nervous system (CNS) autoimmunity and compare it to populations of CNS-resident memory CD8+T cells emerging from acute viral infection. We find that autoimmune CD8+T cells persisting at sites of self-antigen exhibit characteristic transcriptional regulation together with distinct epigenetic remodeling. This self-reactive CD8+T cell fate depends on the transcriptional regulation by the DNA-binding HMG-box protein TOX which remodels more than 400 genomic regions including loci such asTcf7, which is central to stemness of CD8+T cells. Continuous exposure to CNS self-antigen sustains TOX levels in self-reactive CD8+T cells, whereas genetic ablation of TOX in CD8+T cells results in shortened persistence of self-reactive CD8+T cells in the inflamed CNS. Our study establishes and characterizes the genetic differentiation program enabling chronic T cell-driven immunopathology in CNS autoimmunity.