bluuebunny/crossref_metadata_2025 huggingface dataset:
Cloud Resolving WRF Simulations of Precipitation and Soil Moisture Over the Central Tibetan Plateau: An Assessment of Various Physics Options
Authors: Lv Meizhao , Xu Zhongfeng , Yang Zong‐Liang
Published: January 2020

The evaluation of the regional climate model is of great importance for model's developments and applications. We assessed the performance of Weather Research and Forecasting (WRF) cloud resolving simulations with various physics options in terms of precipitation and soil moisture over the central Tibetan Plateau (TP) for a 2‐month simulation from July to August in 2015. The simulated precipitation is most sensitive to the microphysics scheme, followed by the land surface model, which plays a vital role in the soil moisture simulation, while the planetary boundary layer and radiation schemes have relatively minor impacts on the precipitation and soil moisture. Specifically, the heavy precipitation event has a close relationship with the land surface model. Among the different WRF schemes, the new Thompson microphysics scheme, the Noah land surface model, the GFDL radiation scheme, and the Mellor–Yamada planetary boundary layer scheme perform relatively better than other options over the central TP. In contrast, the Lin and WRF Single‐Moment 6‐class microphysics schemes tend to simulate an earlier precipitation peak in the diurnal cycle, excessively higher intensities, and greater frequencies for high precipitation events. The Rapid Update Cycle model performs the worst in the spatiotemporal pattern of precipitation and markedly exaggerates the diurnal variation of soil moisture. These results can provide valuable guidance for further fine‐scale simulation studies of land–atmosphere interaction over the TP.
Coseismic Rupture Geometry and Slip Rupture Process During the 2018 Mw 7.1 Anchorage, South‐Central Alaska Earthquake: Intraplate Normal Faulting by Slab Tear Constrained by Geodetic and Teleseismic Data
Authors: He Ping , Wen Yangmao , Chen Yunguo , Xu Caijun , Ding Kaihua
Published: January 2020

The Mw 7.1 Anchorage earthquake on 30 November 2018 beneath the south‐central Alaska is a rare intermediate‐depth event larger than Mw 7 that occurred in a complex subduction region, where the young Yakutat oceanic terrane wedges in the continental‐oceanic plate collisional region between the Pacific oceanic plate and the North American plate. We use both ascending and descending Sentinel‐1 satellite Interferometric Synthetic Aperture Radar (InSAR) images to construct the coseismic displacement associated with this earthquake, which shows a nearly circular deformation pattern with a subsidence of ~4 cm in line of sight direction. Combining coseismic GPS data, we determine the focal mechanism of this event dominated by normal faulting with N‐S striking of 186°and westward dipping of 64°by using a uniform slip model. Then we find a preferred slip model with both geodetic data and teleseismic data, suggesting the main slips are concentrated on a depth of 55–75 km. The total released moment of our preferred slip model is 5.32 × 1019N·m, equivalent to Mw 7.1. The rupture process includes two peaks terminating at about 18 s and indicates a unilateral rupture with its front propagating northwestward direction at an average speed of 2.5 km/s. In comparison with the detailed seismic image in this region, this event just occurred in the Yakutat terrane beneath a low velocity zone, suggesting it was caused by slab tear but not slab boundary breaking and determining the lower boundary of shallow thrust‐slip in the Alaska subduction zone.
A Multifidelity Framework and Uncertainty Quantification for Sea Surface Temperature in the Massachusetts and Cape Cod Bays
Authors: Babaee H. , Bastidas C. , DeFilippo M. , Chryssostomidis C. , Karniadakis G. E.
Published: January 2020

We present a multifidelity framework to analyze and hindcast predictions of sea surface temperature (SST) in the Massachusetts and Cape Cod Bays, which is a critical area for its ecological significance, sustaining fisheries and the blue economy of the region. Currently, there is a lack of accurate and continuous SST prediction for this region due to the high cost of collecting the samples (e.g., cost of buoys, maintenance, severe weather). In this work, we use SST data from satellite images and in situ measurements collected by the Massachusetts Water Resources Authority to develop multifidelity forecasting models. This multifidelity framework is based on autoregressive Gaussian process schemes that systematically exploit all correlations between data from multiple heterogeneous spatiotemporal sources with various degrees of fidelity. This enables us to obtain implicitly their functional relationships and, at the same time, quantify the uncertainty of the data‐driven predictions. Specifically, in the current work, we develop and validate progressively more complex models, including temporal, spatial, and spatiotemporal multifidelity hindcast predictions of SST in the Massachusetts and Cape Cod Bays. Together with these predictions, we present for the first time uncertainty maps for the region.
Scales of Stress Heterogeneity Near Active Faults in the Santa Barbara Channel, Southern California
Authors: Persaud Patricia , Pritchard Edward H. , Stock Joann M.
Published: January 2020

The Santa Barbara Channel represents the offshore portion of the Ventura Basin in Southern California. Ongoing transpression related to a regional left step in the San Andreas Fault has led to the formation of E‐W trending en‐echelon fault systems that accommodate localized shortening across the basin. Recent studies have suggested that faults within the channel could be capable of a multisegment rupture and producing a Mw 7.7–8.1 tsunamigenic earthquake. However, dynamic rupture models producing these results do not account for stress heterogeneity. With only sparse information available on the stress field in this region, further borehole‐derived stress constraints are essential for obtaining a more comprehensive understanding of the hazards related to the complex fault systems. We used caliper logs from 19 wells obtained from industry to identify stress‐induced borehole breakouts beneath the Holly and Gail oil platforms in the channel. Our newly developed forward modeling technique provides constraints on the orientations and relative magnitudes of the three principal stresses. At Gail, we determine a reverse faulting stress regime (SHmax = 1.7; Shmin = 1.6; SV = 1.0) and an SHmax azimuth of N45°E. Our results are consistent with local structures, which reflect deeper regional scale trends, and with similar studies onshore nearby. At Holly, an SHmax rotation from ~N36°W to ~N57°E occurs across ~100 m depth in a single well and differs from nearby results, indicating that short‐length scale (<10 km laterally and <1 km in depth) stress heterogeneity is associated with complex changes in fault geometry.
The Henkel Petrophysical Plot: Mineralogy and Lithology From Physical Properties
Authors: Enkin Randolph J. , Hamilton Tark S. , Morris William A.
Published: January 2020

The Henkel plot (logarithm of magnetic susceptibility versus density of rock samples) reveals that most rocks fall on either a “magnetite trend” or a “paramagnetic trend.” Interpretation of gravity and magnetic surveys is improved when the mineralogical and lithological basis of these trends is understood. We present a quantitative mineralogical mixing model, involving the components QFC (quartz‐feldspar‐calcite), FM (ferromagnesian silicates), and M (magnetite) and discuss the geological processes which produce or modify these mixtures. Igneous rocks mostly plot on the magnetite trend, where the FM/M ratio is about 10. The density‐susceptibility mineralogical mixing model is compatible with the CIPW mineral calculation for igneous classification from chemical analyses. Sedimentary and metamorphic processes usually involve oxidation, reduction, and/or iron loss, all which are magnetite‐destructive and lead to petrophysical measurements along the paramagnetic trend where FM/M > 1,000. Mineralization, with the introduction of sulfides and oxides, leads to dense rocks which do not plot along the magnetite nor paramagnetic trends. This quantitative analysis provides a method to integrate geological processes in the interpretation of geophysical surveys.
Topographic Fingerprint of Deep Mantle Subduction
Authors: Briaud Arthur , Agrusta Roberto , Faccenna Claudio , Funiciello Francesca , van Hunen Jeroen
Published: January 2020

The dynamic topography links with the mantle structures at various temporal and spatial scales. However, it is still unclear how it relates to the dynamics of subducting lithosphere when plates reach the mantle transition zone and lower mantle. Seismic tomography images show how slab morphologies vary from sinking subvertically into the lower mantle, to lying flat above the upper‐lower mantle discontinuity, to thickening in the shallow lower mantle. These slab shapes have been considered to be the result of variable interaction of the slab with the upper‐lower mantle discontinuity at ~670 km depth. Previous studies show that periodic deep slab dynamics can explain a variety of enigmatic geological and geophysical observations such as periodic variations of the plate velocities, trench retreat and advance episodes, and the scattered distribution of slab dip angle in the upper mantle. In this study, we use two‐dimensional subduction models to investigate the surface topography expression and its evolution during slab transition zone interaction. Our models show that topography does not depend on slab morphology; indeed, the dynamic topography cannot distinguish between a slab sinking straight into the lower mantle and slab stagnation at the upper‐lower mantle boundary. However, topographic oscillations are related to episodes of the trench advance and retreat, which in turn are linked to the slab folding behavior at transition zone depths. Our results suggest that the surface transient signal observed by geological studies could help to detect deep subduction dynamics.
Improved Global Nonlinear Surface Mass Variation Estimates From Geodetic Displacements and Reconciliation With GRACE Data
Authors: Wu Xiaoping , Haines Bruce J. , Heflin Michael B. , Landerer Felix W.
Published: January 2020

Spatiotemporal coverage gaps and the nature of distant signature sources in Global Navigation Satellite System (GNSS) and The Gravity Recovery and Climate Experiment (GRACE) data require global inversions of data combinations for cross validation and complete and continuous monitoring of surface water mass variations. For spectral completeness, accurate data‐based degree‐1 surface mass variation coefficient or equivalent geocenter motion estimates are also desired but very difficult to obtain. To improve the reliability of such estimates, we carry out a new effort to combine different space geodetic technique data in a Kalman filter and time series approach to Terrestrial Reference Frame realization using an advanced formulation. With origin at the center of mass of the Earth system, the new parameterization now includes site displacements in the state vector explicitly for realistic assessment of their covariance matrices. More robust geocenter motion results are achieved when the displacement information is combined further with GRACE gravity data in a unified inversion. Previously, various systematic effects in GNSS data resulted in rather large discrepancies in global surface mass change estimates when compared with those from GRACE gravity data. Here, we show that significantly improved GNSS data after reprocessing and the refined Estimating the Circulation and Climate of the Ocean (ECCO) bottom pressure model reveal a global surface mass variation pattern that has been largely reconciled with that from GRACE data.
Formulation of a Triaxial Three‐Layered Earth Rotation: Theory and Rotational Normal Mode Solutions
Authors: Guo Zhiliang , Shen WenBin
Published: January 2020

In this study, we formulated a triaxial three‐layered anelastic Earth rotation theory considering various core‐mantle couplings, including the pressure and gravitational couplings acting on the elastic inner core by the outer core and mantle, and the viscoelectromagnetic couplings between the outer core and mantle and between the outer and inner cores. With this formulation, using the eigenvalue method, we solved four rotational normal modes, including the Chandler Wobble (CW), Free Core Nutation (FCN), Free Inner Core Nutation (FICN), and the Inner Core Wobble (ICW). The triaxiality of the actual Earth has notable effects on rotational normal modes, that is, 0.005, 0.0,
0.071, and 1.174 d (mean solar days), respectively, for the CW, FCN, FICN, and ICW. In the case that the triaxiality is bigger, for instance, if the Earth's equatorial dynamical ellipticity were
, which is 1 order of magnitude larger than the presently determined ellipticity (
), the CW and ICW periods will be lengthened by 3.579 and 94.912 d, and the FICN period will be decreased by 0.591 d. Based on our present knowledge, the numerical solutions of the four normal modes under the new rotation frame suggest that the periods of CW, FCN, FICN, and ICW are, respectively, 432.2, 429.9, 934.0, and 2,718.7 d. Our theory for Earth can be extended to other planets in our solar system.
Salinity Affects Topsoil Organic Carbon Concentrations Through Regulating Vegetation Structure and Productivity
Authors: Xue Lian , Jiang Junyan , Li Xiuzhen , Yan Zhongzheng , Zhang Qian , Ge Zhenming , Tian Bo , Craft Christopher
Published: January 2020

Estuarine salt marshes have been recognized as one of the most efficient carbon sinks in the biosphere, with considerable potential for climate change mitigation. However, there are still uncertainties about the response of soil carbon stocks to enhanced soil salinization caused by accelerated sea‐level rises and aggravated saltwater intrusion. We therefore conducted both field investigations in the Chongming Dongtan salt marsh of the Yangtze River Estuary, China, and manipulative experiments on marsh soils occupied, respectively, by the invasive Spartina alterniflora, and the native Phragmites australis and Scirpus mariqueter, to identify the effects of elevated soil salinity on top soil organic carbon (SOC) concentration. Our field data showed that SOC concentrations were significantly positively associated with soil salinity concentrations, annual net primary productivity, and marsh surface elevation but showed a significant negative relationship with median grain size. Compared with the two native species, S. alterniflora preferred more saline conditions and had a higher SOC concentration. Although raised flooding salinities (0–35 ppt) did not strongly affect SOC concentrations, elevated soil salinities significantly corresponded with low SOC concentrations and plant biomass in manipulative experiments. These findings indicated that soil salinity, plant species, and soil texture were key factors controlling SOC concentrations in the studied salt marsh. Moreover, soil salinity could affect SOC concentrations through regulating vegetation spatial structure and plant biomass production. The further invasion of the S. alterniflora community will exert a positive influence on SOC concentrations in the Chongming Dongtan salt marsh.
Radio Monitoring of Dynamic Processes in the Ionosphere Over China During the Partial Solar Eclipse of 11 August 2018
Authors: Guo Q. , Chernogor L. F. , Garmash K. P. , Rozumenko V. T. , Zheng Y.
Published: January 2020

We briefly describe the multifrequency multiple‐path radio system and illustrate its observational capabilities by performing, as an example, the study of dynamic processes that occurred in the ionosphere over China during the partial solar eclipse on August 11 2018. This system, based on the software‐defined radio technology and capable of operating in the 10‐kHz to 30‐MHz band, has been developed jointly by Harbin Engineering University, the People's Republic of China, where it is located, and V. N. Karazin National University, Ukraine. The principle of the system operation is based on measurements of a Doppler shift of frequency. The implementation of Marple's algorithm for autoregression spectrum analysis has permitted an increase in a Doppler resolution down to 0.02 Hz and in a temporal resolution down to 7.5 s. The number of radio propagation paths and their orientation depend on the specifics of problems being solved. The interpretation of the eclipse effects is complicated by processes launched by the dusk terminator. The eclipse was associated with an increase in the number of rays, the generation of oscillation processes in the atmospheric gravity wave range of periods, and with a negative Doppler shift of frequency at first and a positive shift of smaller magnitude subsequently. The solar eclipse launched ~9–14% amplitude quasiperiodic oscillations in the electron density, while a maximum decrease of order 26% was observed over the Hailar–Harbin path in the ionospheric E region. The latter value does not virtually differ from theoretical estimates.
Measuring the Earth's Synchrotron Emission From Radiation Belts With a Lunar Near Side Radio Array
Authors: Hegedus Alexander , Nénon Quentin , Brunet Antoine , Kasper Justin , Sicard Angélica , Cecconi Baptiste , MacDowall Robert , Baker Daniel
Published: January 2020

The high kinetic energy electrons that populate the Earth's radiation belts emit synchrotron emissions because of their interaction with the planetary magnetic field. A lunar near side array would be uniquely positioned to image this emission and provide a near real time measure of how the Earth's radiation belts are responding to the current solar input. The Salammbô code is a physical model of the dynamics of the three‐dimensional phase‐space electron densities in the radiation belts, allowing the prediction of 1‐keV to 100‐MeV electron distributions trapped in the belts. This information is put into a synchrotron emission simulator that provides the brightness distribution of the emission up to 1 MHz from a given observation point. Using Digital Elevation Models from Lunar Reconnaissance Orbiter Lunar Orbiter Laser Altimeter data, we select a set of locations near the Lunar sub‐Earth point with minimum elevation variation over various‐sized patches where we simulate radio receivers to create a synthetic aperture. We consider all realistic noise sources in the low‐frequency regime. We then use a custom Common Astronomy Software Applications code to image and process the data from our defined array, using SPICE to align the lunar coordinates with the Earth. We find that for a moderate lunar surface electron density of 250/cm
, the radiation belts may be detected every 12–24 hr with a 16,384‐element array over a 100‐km‐diameter circle. Changing electron density can make measurements 10 times faster at lunar night and 10 times slower at lunar noon.
Flying Through Uncertainty
Authors: Berger T. E. , Holzinger M. J. , Sutton E. K. , Thayer J. P.
Published: January 2020

Space weather is the main source of uncertainty in the position of all objects in low Earth orbit (LEO) below about 1,000 km. The main impact is strong variation in the neutral density of the thermosphere as it responds to radiative inputs from the Sun in the extreme ultraviolet wavelength range, energetic particle precipitation in the high‐latitude auroral zones, and global‐scale electrical currents generated during geomagnetic storms. Waves and instabilities from the lower atmosphere can also influence thermospheric density in complex ways. The variation in neutral density leads to variable drag forces on satellites flying through the thermosphere, which in turn causes orbital track changes. We currently lack the ability to accurately model and predict the neutral density changes in the thermosphere in response to space weather inputs. Operational empirical models of thermospheric density are inaccurate during space weather events, and mandate that LEO orbital tracks carry large “error ellipsoids” around all objects to account for positional uncertainty. This leads to many more “conjunction” warnings than necessary as large error ellipsoids are frequently calculated to intersect in orbit. As the LEO domain becomes more crowded with the advent of commercial “megaconstellations” we face a growing challenge to reduce orbital uncertainties by developing whole atmosphere models to enable timely and accurate forecasts of thermospheric conditions. We recommend that researchers, forecasters, and policy makers coordinate to ensure that space weather research and forecasting is tightly integrated into upcoming changes to the operational Space Traffic Management system.
Orogenesis in Paleo‐Mesoproterozoic Eastern Australia: A response to Arc‐Continent and Continent‐Continent Collision During Assembly of the Nuna Supercontinent
Authors: Gibson G. M. , Champion D. C. , Huston D. L. , Withnall I. W.
Published: January 2020

Northern and southern Australia preserve a common record of 1790–1655 Ma intracontinental rifting and backarc extension culminating in formation of a marginal sea that subsequently collapsed following a 1650–1640 Ma reversal in plate motion and onset of arc‐continent collision. Arc‐continent collision was accompanied by intermediate‐pressure Barrovian‐type metamorphism (6–8 kb) and widespread crustal thickening as reflected in a clockwise pressure‐temperature‐time path. Later metamorphism during the 1620–1580 Ma Isa and Olary orogenies occurred under intrusion‐enhanced lower pressure conditions (4–6 kb) and followed a counterclockwise pressure‐temperature‐time path incompatible with either significant amounts of crustal thickening or tectonic models which have Australia and Laurentia commencing collision at this time. Continent‐continent collision more likely followed on closely behind arc‐continent collision (Riversleigh Tectonic Event), precipitating a switch in crustal shortening from northeast‐southwest to west‐east as the older rift template and underlying basement structures were reactivated in a transpressive or multicollisional tectonic regime not unlike that which produced the Himalayan‐Tibet orogenic system. As in the latter, ongoing collision was accommodated by thrusting, extensional collapse and lateral extrusion of still thermally weak crust on orogen‐parallel strike‐slip faults, resulting in formation of the west‐east‐striking Isa Superbasin, isothermal decompression and granite intrusion from 1620 Ma. A comparable record of deformation, metamorphism, and magmatic intrusion from 1650 until 1600 Ma has been documented for northern and southern North America (Forward/Racklan and Mazatzal orogenies) indicating that Laurentia and Australia were likely proximal to each other throughout this period.
Topographic and Tectonic Evolution of Mountain Belts Controlled by Salt Thickness and Rift Architecture
Authors: Jourdon Anthony , Mouthereau Frédéric , Le Pourhiet Laetitia , Callot Jean‐Paul
Published: January 2020

The role of the heterogeneous rheological architecture of rifted margins in the building of mountain belts has challenged our view of how a collisional orogen formed. We show, using two‐dimensional numerical experiments of collision built by the inversion of rifted margins, that a weak pre‐extensional evaporitic layer delays the growth of topography and the onset of syn‐orogenic sedimentary record in foreland basins. In tectonic models lacking a weak décollement layer, the orogen grows by progressive accretion of basement thrusts. With a 2‐km‐thick salt layer, the orogen develops an antiformal stack in the deep crust that is kinematically connected to a shallow thin‐skin thrust belt in the foreland as observed in many orogens. A 5‐km‐thick weak layer leads to the quasi‐absence of topography and widespread salt tectonics and obliterates thrusts propagation while promoting crust and mantle underthrusting. During convergence, the preservation of a marine seaway emphasizes that collision may involve a significant period of submarine continental accretion, which duration is controlled by the thickness of the weak décollement layer. From these experiments we infer that the thicker the salt layer, the longer the delay between the onset of far‐field shortening and the formation of the orogen. Our study explains first‐order features recognized in many orogens controlled by variable salt thickness and extension.
Value of Crowd‐Based Water Level Class Observations for Hydrological Model Calibration
Authors: Etter S. , Strobl B. , Seibert J. , van Meerveld H. J. Ilja
Published: January 2020

While hydrological models generally rely on continuous streamflow data for calibration, previous studies have shown that a few measurements can be sufficient to constrain model parameters. Other studies have shown that continuous water level or water level class (WL‐class) data can be informative for model calibration. In this study, we combined these approaches and explored the potential value of a limited number of WL‐class observations for calibration of a bucket‐type runoff model (HBV) for four catchments in Switzerland. We generated synthetic data to represent citizen science data and examined the effects of the temporal resolution of the observations, the numbers of WL‐classes, and the magnitude of the errors in the WL‐class observations on the model validation performance. Our results indicate that on average one observation per week for a 1‐year period can significantly improve model performance compared to the situation without any streamflow data. Furthermore, the validation performance for model parameters calibrated with WL‐class observations was similar to the performance of the calibration with precise water level measurements. The number of WL‐classes did not influence the validation performance noticeably when at least four WL‐classes were used. The impact of typical errors for citizen science‐based estimates of WL‐classes on the model performance was small. These results are encouraging for citizen science projects where citizens observe water levels for otherwise ungauged streams using virtual or physical staff gauges.
Divergent symbiont communities determine the physiology and nutrition of a reef coral across a light-availability gradient
Authors: Wall Christopher B , Kaluhiokalani Mario , Popp Brian N , Donahue Megan J , Gates Ruth D
Published: January 2020

Reef corals are mixotrophic organisms relying on symbiont-derived photoautotrophy and water column heterotrophy. Coral endosymbionts (Family: Symbiodiniaceae), while typically considered mutualists, display a range of species-specific and environmentally mediated opportunism in their interactions with coral hosts, potentially requiring corals to rely more on heterotrophy to avoid declines in performance. To test the influence of symbiont communities on coral physiology (tissue biomass, symbiont density, photopigmentation) and nutrition (δ13C, δ15N), we sampled Montipora capitata colonies dominated by a specialist symbiont Cladocopium spp. or a putative opportunist Durusdinium glynnii (hereafter, C- or D-colonies) from Kāne‘ohe Bay, Hawai‘i, across gradients in photosynthetically active radiation (PAR) during summer and winter. We report for the first time that isotope values of reef corals are influenced by Symbiodiniaceae communities, indicative of different autotrophic capacities among symbiont species. D-colonies had on average 56% higher symbiont densities, but lower photopigments per symbiont cell and consistently lower δ13C values in host and symbiont tissues; this pattern in isotope values is consistent with lower symbiont carbon assimilation and translocation to the host. Neither C- nor D-colonies showed signs of greater heterotrophy or nutritional plasticity; instead changes in δ13C values were driven by PAR availability and photoacclimation attributes that differed between symbiont communities. Together, these results reveal Symbiodiniaceae functional diversity produces distinct holobionts with different capacities for autotrophic nutrition, and energy tradeoffs from associating with opportunist symbionts are not met with increased heterotrophy.
Disruption of Dhcr7 and Insig1/2 in cholesterol metabolism causes defects in bone formation and homeostasis through primary cilium formation
Authors: Suzuki Akiko , Ogata Kenichi , Yoshioka Hiroki , Shim Junbo , Wassif Christopher A. , Porter Forbes D. , Iwata Junichi
Published: January 2020

Human linkage studies suggest that craniofacial deformities result from either genetic mutations related to cholesterol metabolism or high-cholesterol maternal diets. However, little is known about the precise roles of intracellular cholesterol metabolism in the development of craniofacial bones, the majority of which are formed through intramembranous ossification. Here, we show that an altered cholesterol metabolic status results in abnormal osteogenesis through dysregulation of primary cilium formation during bone formation. We found that cholesterol metabolic aberrations, induced through disruption of eitherDhcr7(which encodes an enzyme involved in cholesterol synthesis) orInsig1andInsig2(which provide a negative feedback mechanism for cholesterol biosynthesis), result in osteoblast differentiation abnormalities. Notably, the primary cilia responsible for sensing extracellular cues were altered in number and length through dysregulated ciliary vesicle fusion inDhcr7andInsig1/2mutant osteoblasts. As a consequence, WNT/β-catenin and hedgehog signaling activities were altered through dysregulated primary cilium formation. Strikingly, the normalization of defective cholesterol metabolism by simvastatin, a drug used in the treatment of cholesterol metabolic aberrations, rescued the abnormalities in both ciliogenesis and osteogenesis in vitro and in vivo. Thus, our results indicate that proper intracellular cholesterol status is crucial for primary cilium formation during skull formation and homeostasis.
Inflammation-induced inhibition of chaperone-mediated autophagy maintains the immunosuppressive function of murine mesenchymal stromal cells
Authors: Zhang Jie , Huang Jiefang , Gu Yuting , Xue Mingxing , Qian Fengtao , Wang Bei , Yang Wanlin , Yu Hongshuang , Wang Qiwei , Guo Xin , Ding Xinyuan , Wang Jina , Jin Min , Zhang Yanyun
Published: January 2020

Macroautophagy has been implicated in modulating the therapeutic function of mesenchymal stromal cells (MSCs). However, the biological function of chaperone-mediated autophagy (CMA) in MSCs remains elusive. Here, we found that CMA was inhibited in MSCs in response to the proinflammatory cytokines interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α). In addition, suppression of CMA by knocking down the CMA-related lysosomal receptor lysosomal-associated membrane protein 2 (LAMP-2A) in MSCs significantly enhanced the immunosuppressive effect of MSCs on T cell proliferation, and as expected, LAMP-2A overexpression in MSCs exerted the opposite effect on T cell proliferation. This effect of CMA on the immunosuppressive function of MSCs was attributed to its negative regulation of the expression of chemokine C-X-C motif ligand 10 (CXCL10), which recruits inflammatory cells, especially T cells, to MSCs, and inducible nitric oxide synthase (iNOS), which leads to the subsequent inhibition of T cell proliferation via nitric oxide (NO). Mechanistically, CMA inhibition dramatically promoted IFN-γ plus TNF-α-induced activation of NF-κB and STAT1, leading to the enhanced expression of CXCL10 and iNOS in MSCs. Furthermore, we found that IFN-γ plus TNF-α-induced AKT activation contributed to CMA inhibition in MSCs. More interestingly, CMA-deficient MSCs exhibited improved therapeutic efficacy in inflammatory liver injury. Taken together, our findings established CMA inhibition as a critical contributor to the immunosuppressive function of MSCs induced by inflammatory cytokines and highlighted a previously unknown function of CMA.
A wind-albedo-wind feedback driven by landscape evolution
Authors: Abell Jordan T. , Pullen Alex , Lebo Zachary J. , Kapp Paul , Gloege Lucas , Metcalf Andrew R. , Nie Junsheng , Winckler Gisela
Published: January 2020

The accurate characterization of near-surface winds is critical to our understanding of past and modern climate. Dust lofted by these winds has the potential to modify surface and atmospheric conditions as well as ocean biogeochemistry. Stony deserts, low dust emitting regions today, represent expansive areas where variations in surficial geology through time may drastically impact near-surface conditions. Here we use the Weather Research and Forecasting (WRF) model over the western Gobi Desert to demonstrate a previously undocumented process between wind-driven landscape evolution and boundary layer conditions. Our results show that altered surficial thermal properties through winnowing of fine-grained sediments and formation of low-albedo gravel-mantled surfaces leads to an increase in near-surface winds by up to 25%; paradoxically, wind erosion results in faster winds regionally. This wind-albedo-wind feedback also leads to an increase in the frequency of hours spent at higher wind speeds, which has implications for dust emission potential.
Mitochondrial TCA cycle metabolites control physiology and disease
Authors: Martínez-Reyes Inmaculada , Chandel Navdeep S.
Published: January 2020

Mitochondria are signaling organelles that regulate a wide variety of cellular functions and can dictate cell fate. Multiple mechanisms contribute to communicate mitochondrial fitness to the rest of the cell. Recent evidence confers a new role for TCA cycle intermediates, generally thought to be important for biosynthetic purposes, as signaling molecules with functions controlling chromatin modifications, DNA methylation, the hypoxic response, and immunity. This review summarizes the mechanisms by which the abundance of different TCA cycle metabolites controls cellular function and fate in different contexts. We will focus on how these metabolites mediated signaling can affect physiology and disease.
Catalytic processing in ruthenium-based polyoxometalate coacervate protocells
Authors: Gobbo Pierangelo , Tian Liangfei , Pavan Kumar B. V. V. S , Turvey Samuel , Cattelan Mattia , Patil Avinash J. , Carraro Mauro , Bonchio Marcella , Mann Stephen
Published: January 2020

The development of programmable microscale materials with cell-like functions, dynamics and collective behaviour is an important milestone in systems chemistry, soft matter bioengineering and synthetic protobiology. Here, polymer/nucleotide coacervate micro-droplets are reconfigured into membrane-bounded polyoxometalate coacervate vesicles (PCVs) in the presence of a bio-inspired Ru-based polyoxometalate catalyst to produce synzyme protocells (Ru4PCVs) with catalase-like activity. We exploit the synthetic protocells for the implementation of multi-compartmentalized cell-like models capable of collective synzyme-mediated buoyancy, parallel catalytic processing in individual horseradish peroxidase-containing Ru4PCVs, and chemical signalling in distributed or encapsulated multi-catalytic protocell communities. Our results highlight a new type of catalytic micro-compartment with multi-functional activity and provide a step towards the development of protocell reaction networks.
Ultrasensitive negative capacitance phototransistors
Authors: Tu Luqi , Cao Rongrong , Wang Xudong , Chen Yan , Wu Shuaiqin , Wang Fang , Wang Zhen , Shen Hong , Lin Tie , Zhou Peng , Meng Xiangjian , Hu Weida , Liu Qi , Wang Jianlu , Liu Ming , Chu Junhao
Published: January 2020

Sensitive photodetection is crucial for modern optoelectronic technology. Two-dimensional molybdenum disulfide (MoS2) with unique crystal structure, and extraordinary electrical and optical properties is a promising candidate for ultrasensitive photodetection. Previously reported methods to improve the performance of MoS2 photodetectors have focused on complex hybrid systems in which leakage paths and dark currents inevitably increase, thereby reducing the photodetectivity. Here, we report an ultrasensitive negative capacitance (NC) MoS2 phototransistor with a layer of ferroelectric hafnium zirconium oxide film in the gate dielectric stack. The prototype photodetectors demonstrate a hysteresis-free ultra-steep subthreshold slope of 17.64 mV/dec and ultrahigh photodetectivity of 4.75 × 1014 cm Hz1/2 W−1 at room temperature. The enhanced performance benefits from the combined action of the strong photogating effect induced by ferroelectric local electrostatic field and the voltage amplification based on ferroelectric NC effect. These results address the key challenges for MoS2 photodetectors and offer inspiration for the development of other optoelectronic devices.
Fluorinated hybrid solid-electrolyte-interphase for dendrite-free lithium deposition
Authors: Pathak Rajesh , Chen Ke , Gurung Ashim , Reza Khan Mamun , Bahrami Behzad , Pokharel Jyotshna , Baniya Abiral , He Wei , Wu Fan , Zhou Yue , Xu Kang , Qiao Qiquan
Published: January 2020

Lithium metal anodes have attracted extensive attention owing to their high theoretical specific capacity. However, the notorious reactivity of lithium prevents their practical applications, as evidenced by the undesired lithium dendrite growth and unstable solid electrolyte interphase formation. Here, we develop a facile, cost-effective and one-step approach to create an artificial lithium metal/electrolyte interphase by treating the lithium anode with a tin-containing electrolyte. As a result, an artificial solid electrolyte interphase composed of lithium fluoride, tin, and the tin-lithium alloy is formed, which not only ensures fast lithium-ion diffusion and suppresses lithium dendrite growth but also brings a synergistic effect of storing lithium via a reversible tin-lithium alloy formation and enabling lithium plating underneath it. With such an artificial solid electrolyte interphase, lithium symmetrical cells show outstanding plating/stripping cycles, and the full cell exhibits remarkably better cycling stability and capacity retention as well as capacity utilization at high rates compared to bare lithium.
An in vitro platform for engineering and harnessing modular polyketide synthases
Authors: Miyazawa Takeshi , Hirsch Melissa , Zhang Zhicheng , Keatinge-Clay Adrian T.
Published: January 2020

To harness the synthetic power of modular polyketide synthases (PKSs), many aspects of their biochemistry must be elucidated. A robust platform to study these megadalton assembly lines has not yet been described. Here, we in vitro reconstitute the venemycin PKS, a short assembly line that generates an aromatic product. Incubating its polypeptides, VemG and VemH, with 3,5-dihydroxybenzoic acid, ATP, malonate, coenzyme A, and the malonyl-CoA ligase MatB, venemycin production can be monitored by HPLC and NMR. Multi-milligram quantities of venemycin are isolable from dialysis-based reactors without chromatography, and the enzymes can be recycled. Assembly line engineering is performed using pikromycin modules, with synthases designed using the updated module boundaries outperforming those using the traditional module boundaries by over an order of magnitude. Using combinations of VemG, VemH, and their engineered derivatives, as well as the alternate starter unit 3-hydroxybenzoic acid, a combinatorial library of six polyketide products is readily accessed.
Integrative discovery of treatments for high-risk neuroblastoma
Authors: Almstedt Elin , Elgendy Ramy , Hekmati Neda , Rosén Emil , Wärn Caroline , Olsen Thale Kristin , Dyberg Cecilia , Doroszko Milena , Larsson Ida , Sundström Anders , Arsenian Henriksson Marie , Påhlman Sven , Bexell Daniel , Vanlandewijck Michael , Kogner Per , Jörnsten Rebecka , Krona Cecilia , Nelander Sven
Published: January 2020

Despite advances in the molecular exploration of paediatric cancers, approximately 50% of children with high-risk neuroblastoma lack effective treatment. To identify therapeutic options for this group of high-risk patients, we combine predictive data mining with experimental evaluation in patient-derived xenograft cells. Our proposed algorithm, TargetTranslator, integrates data from tumour biobanks, pharmacological databases, and cellular networks to predict how targeted interventions affect mRNA signatures associated with high patient risk or disease processes. We find more than 80 targets to be associated with neuroblastoma risk and differentiation signatures. Selected targets are evaluated in cell lines derived from high-risk patients to demonstrate reversal of risk signatures and malignant phenotypes. Using neuroblastoma xenograft models, we establish CNR2 and MAPK8 as promising candidates for the treatment of high-risk neuroblastoma. We expect that our method, available as a public tool (targettranslator.org), will enhance and expedite the discovery of risk-associated targets for paediatric and adult cancers.
Absence of internal multidecadal and interdecadal oscillations in climate model simulations
Authors: Mann Michael E. , Steinman Byron A. , Miller Sonya K.
Published: January 2020

For several decades the existence of interdecadal and multidecadal internal climate oscillations has been asserted by numerous studies based on analyses of historical observations, paleoclimatic data and climate model simulations. Here we use a combination of observational data and state-of-the-art forced and control climate model simulations to demonstrate the absence of consistent evidence for decadal or longer-term internal oscillatory signals that are distinguishable from climatic noise. Only variability in the interannual range associated with the El Niño/Southern Oscillation is found to be distinguishable from the noise background. A distinct (40–50 year timescale) spectral peak that appears in global surface temperature observations appears to reflect the response of the climate system to both anthropogenic and natural forcing rather than any intrinsic internal oscillation. These findings have implications both for the validity of previous studies attributing certain long-term climate trends to internal low-frequency climate cycles and for the prospect of decadal climate predictability.
Fast and accurate sCMOS noise correction for fluorescence microscopy
Authors: Mandracchia Biagio , Hua Xuanwen , Guo Changliang , Son Jeonghwan , Urner Tara , Jia Shu
Published: January 2020

The rapid development of scientific CMOS (sCMOS) technology has greatly advanced optical microscopy for biomedical research with superior sensitivity, resolution, field-of-view, and frame rates. However, for sCMOS sensors, the parallel charge-voltage conversion and different responsivity at each pixel induces extra readout and pattern noise compared to charge-coupled devices (CCD) and electron-multiplying CCD (EM-CCD) sensors. This can produce artifacts, deteriorate imaging capability, and hinder quantification of fluorescent signals, thereby compromising strategies to reduce photo-damage to live samples. Here, we propose a content-adaptive algorithm for the automatic correction of sCMOS-related noise (ACsN) for fluorescence microscopy. ACsN combines camera physics and layered sparse filtering to significantly reduce the most relevant noise sources in a sCMOS sensor while preserving the fine details of the signal. The method improves the camera performance, enabling fast, low-light and quantitative optical microscopy with video-rate denoising for a broad range of imaging conditions and modalities.
Gastric squamous-columnar junction contains a large pool of cancer-prone immature osteopontin responsive Lgr5−CD44+ cells
Authors: Fu Dah-Jiun , Wang Lianghai , Chouairi Fouad K. , Rose Ian M. , Abetov Danysh A. , Miller Andrew D. , Yamulla Robert J. , Schimenti John C. , Flesken-Nikitin Andrea , Nikitin Alexander Yu.
Published: January 2020

Areas of a junction between two types of epithelia are known to be cancer-prone in many organ systems. However, mechanisms for preferential malignant transformation at the junction areas remain insufficiently elucidated. Here we report that inactivation of tumor suppressor genes Trp53 and Rb1 in the gastric squamous-columnar junction (SCJ) epithelium results in preferential formation of metastatic poorly differentiated neoplasms, which are similar to human gastroesophageal carcinoma. Unlike transformation-resistant antral cells, SCJ cells contain a highly proliferative pool of immature Lgr5−CD44+ cells, which are prone to transformation in organoid assays, comprise early dysplastic lesions, and constitute up to 30% of all neoplastic cells. CD44 ligand osteopontin (OPN) is preferentially expressed in and promotes organoid formation ability and transformation of the SCJ glandular epithelium. OPN and CD44 overexpression correlate with the worst prognosis of human gastroesophageal carcinoma. Thus, detection and selective targeting of the active OPN-CD44 pathway may have direct clinical relevance.
A shared genetic basis of mimicry across swallowtail butterflies points to ancestral co-option of doublesex
Authors: Palmer Daniela H. , Kronforst Marcus R.
Published: January 2020

Uncovering whether convergent adaptations share a genetic basis is consequential for understanding the evolution of phenotypic diversity. This information can help us understand the extent to which shared ancestry or independent evolution shape adaptive phenotypes. In this study, we first ask whether the same genes underlie polymorphic mimicry in Papilio swallowtail butterflies. By comparing signatures of genetic variation between polymorphic and monomorphic species, we then investigate how ancestral variation, hybridization, and independent evolution contributed to wing pattern diversity in this group. We report that a single gene, doublesex (dsx), controls mimicry across multiple taxa, but with species-specific patterns of genetic differentiation and linkage disequilibrium. In contrast to widespread examples of phenotypic evolution driven by introgression, our analyses reveal distinct mimicry alleles. We conclude that mimicry evolution in this group was likely facilitated by ancestral polymorphism resulting from early co-option of dsx as a mimicry locus, and that evolutionary turnover of dsx alleles may underlie the wing pattern diversity of extant polymorphic and monomorphic lineages.
Simulated microgravity in the ring-sheared drop
Authors: McMackin Patrick M. , Griffin Shannon R. , Riley Frank P. , Gulati Shreyash , Debono Nicholas E. , Raghunandan Aditya , Lopez Juan M. , Hirsa Amir H.
Published: January 2020

The ring-sheared drop is a module for the International Space Station to study sheared fluid interfaces and their influence on amyloid fibril formation. A 2.54-cm diameter drop is constrained by a stationary sharp-edged ring at some latitude and sheared by the rotation of another ring in the other hemisphere. Shearing motion is conveyed primarily by the action of surface shear viscosity. Here, we simulate microgravity in the laboratory using a density-matched liquid surrounding the drop. Upon shearing, the drop’s deformation away from spherical is found to be a result of viscous and inertial forces balanced against the capillary force. We also present evidence that the deformation increases with increasing surface shear viscosity.