bluuebunny/crossref_metadata_2025 huggingface dataset:
Paleomagnetism of Paleocene‐Maastrichtian (60–70 Ma) Lava Flows From Tian Shan (Central Asia): Directional Analysis and Paleointensities
Authors: Meng Jun , Lhuillier Florian , Wang Chengshan , Liu Hao , Eid Baha , Li Yalin
Published: August 2020

The Tuoyun volcanics from the Tian Shan range (Central Asia) give an opportunity to investigate the variability of the Earth's magnetic field during the Cretaceous and Early Paleogene. In the paper we focus on Maastrichtian‐Paleocene basalts and report new paleomagnetic results from 70 lava flows (respectively 45 directional groups) sampled near Tuoyun village (75.33°E; 40.18°N) from three distinct sections. Combined with previous results, our new data set yields a virtual geomagnetic pole at φS = 180.2°E, ϑS = 49.5°N with an angular standard deviation
(for N = 93 directional groups). The mean inclination Is = 36.2° is indicative of an emplacement of the Tuoyun volcanics at a paleolatitude around 20°N, consistent with the high dispersion k = 14.6 of the directions. Such an inclination value is 10–15° lower than the predictions from the apparent polar wander paths for stable Europe and East Asia. This observation can be partly explained by crustal shortening within the East Asian plate during the India‐Asia convergence, but also needs to invoke a local field anomaly in Central Asia as previously proposed. Our absolute paleointensity experiments conducted on two lava flows and two baked sedimentary layers yield a mean virtual dipole moment of 58.9 ± 6.9 ZA·m2, consistent with the values at 60–70 Ma in the global paleointensity database. Compared to relative paleointensity results during the Cretaceous Normal Superchron and during the Plio‐Pleistocene, the relative variability in intensity—supposed to be a proxy for the geodynamo's activity—estimated here at 31 ± 5% (N = 15) from pseudo‐Thellier experiments possibly corroborates a correlation between geomagnetic reversal frequency and paleosecular variation rate during the past 120 Myr.
The Sensitivity of the Antarctic Ice Sheet to a Changing Climate: Past, Present, and Future
Authors: Noble T. L. , Rohling E. J. , Aitken A. R. A. , Bostock H. C. , Chase Z. , Gomez N. , Jong L. M. , King M. A. , Mackintosh A. N. , McCormack F. S. , McKay R. M. , Menviel L. , Phipps S. J. , Weber M. E. , Fogwill C. J. , Gayen B. , Golledge N. R. , Gwyther D. E. , Hogg A. McC. , Martos Y. M. , Pena‐Molino B. , Roberts J. , van de Flierdt T. , Williams T.
Published: August 2020

The Antarctic Ice Sheet (AIS) is out of equilibrium with the current anthropogenic‐enhanced climate forcing. Paleoenvironmental records and ice sheet models reveal that the AIS has been tightly coupled to the climate system during the past and indicate the potential for accelerated and sustained Antarctic ice mass loss into the future. Modern observations by contrast suggest that the AIS has only just started to respond to climate change in recent decades. The maximum projected sea level contribution from Antarctica to 2100 has increased significantly since the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report, although estimates continue to evolve with new observational and theoretical advances. This review brings together recent literature highlighting the progress made on the known processes and feedbacks that influence the stability of the AIS. Reducing the uncertainty in the magnitude and timing of the future sea level response to AIS change requires a multidisciplinary approach that integrates knowledge of the interactions between the ice sheet, solid Earth, atmosphere, and ocean systems and across time scales of days to millennia. We start by reviewing the processes affecting AIS mass change, from atmospheric and oceanic processes acting on short time scales (days to decades), through to ice processes acting on intermediate time scales (decades to centuries) and the response to solid Earth interactions over longer time scales (decades to millennia). We then review the evidence of AIS changes from the Pliocene to the present and consider the projections of global sea level rise and their consequences. We highlight priority research areas required to improve our understanding of the processes and feedbacks governing AIS change.
Impact of Scenario Selection on Robustness
Authors: McPhail C. , Maier H. R. , Westra S. , Kwakkel J. H. , van der Linden L.
Published: August 2020

Multiple plausible future scenarios are being used increasingly in preference to a single deterministic or probabilistic prediction of the future in the long‐term planning of water resources systems. These scenarios enable the determination of the robustness of a system—the consideration of performance across a range of plausible futures—and allow an assessment of which possible future system configurations result in a greater level of robustness. There are many approaches to selecting scenarios, and previous studies have observed that the choice of scenarios might affect the estimated robustness of the system. However, these observations have been anecdotal and qualitative. This paper develops a systematic, quantitative methodology for exploring the influence of scenario selection on the robustness and the ranking of decision alternatives. The methodology is illustrated on the Lake Problem. The quantitative results obtained confirm the qualitative observations of previous works, showing that the selection of scenarios is important, as it has a large influence on the robustness value calculated for each decision alternative. However, we show that it has a relatively small influence on how those decision alternatives are ranked. This implies that despite the difference in robustness values, similar decision outcomes will be reached in this case study, regardless of the basis on which the scenarios are obtained. It is also revealed that the impact of the scenarios on the robustness values is due to complex interactions with the system model and robustness metrics.
Random Forest Model of Ultralow‐Frequency Magnetospheric Wave Power
Authors: Bentley S. N. , Stout J. R. , Bloch T. E. , Watt C. E. J.
Published: August 2020

Models of magnetospheric ultralow‐frequency (ULF) waves can be used to study wave phenomena and to calculate the effect of these waves on the energization and transport of radiation belt electrons. We present a decision tree ensemble (i.e., a random forest) model of ground‐based ULF wave power spectral density driven by solar wind speed vsw, north‐south component of the interplanetary magnetic field Bz, and variance of proton number density var(Np). This model corresponds to four radial locations in the magnetosphere (roughly L ∼ 4.21 to 7.94) and spans 1–15 mHz, with hourly magnetic local time resolution. The decision tree ensembles are easier to use than the previous model generation; they have better coverage, perform better at predicting power, and have reduced error due to intelligently chosen bins in parameter space. We outline the difficulties in extracting physics from parameterized models and demonstrate a hypothesis testing framework to iteratively explore finer driving processes. We confirm a regime change for ULF driving about Bz = 0. We posit that ULF wave power directly driven by magnetopause perturbations corresponds to a latitude‐dependent dawn‐dusk asymmetry, which we see with increasing speed. Model uncertainty identifies where the underlying physics is not fully captured; we find that power due to substorms is less well characterized by Bz > 0, with an effect that is seen globally and not just near midnight. The largest uncertainty is seen for the smallest amounts of solar wind driving, suggesting that internal magnetospheric properties may play a significant role in ULF wave occurrence.
This Week: Obsolete Technology and Brand-New Discoveries
Authors:   AGU
Published: August 2020

What Earth and space science stories are we recommending this week?
Climate Change Dominated Long‐Term Soil Carbon Losses of Inner Mongolian Grasslands
Authors: Xin Xiaoping , Jin Dongyan , Ge Yong , Wang Jianghao , Chen Jiquan , Qi Jiaguo , Chu Housen , Shao Changliang , Murray Philip J. , Zhao Ruixue , Qin Qi , Tang Huajun
Published: August 2020

Soil organic carbon (SOC) is the most critical component of global carbon cycle in grassland ecosystems. There has been growing interest in understanding SOC dynamics and driving forces of grassland biomes at various temporal and spatial scales. Up to now, estimates of long‐term and large‐scale changes in SOC of grassland biomes have been mostly based on modeling approaches and manipulative experiments, rather than direct measurements. During 2007–2011, we repeated 141 soil profiles of the sampling in 1963–1964 (up to 1‐m depth) to quantify the long‐term changes of SOC storage in the major grassland types of Inner Mongolia in order to tease apart the relative contributions of climate change and grazing. We found that SOC decreased in all soil types, except in the eolian sandy soils, from 1963 to 2007, with an average reduction rate of 1.8 kg C m−2 (~22.9% or 0.52% year−1) in the grassland biome of Inner Mongolia. We quantitatively clustered the soils into four groups using principal component analysis (PCA) and detected clear spatial dependency of the changes on climate and grazing. The climate change was responsible for 15.3–34.9% of the total SOC variations, whereas grazing intensity accounted for <9.5% of the changes. Our findings indicated that climate change, rather than grazing, was the primary forcing for the changes in SOC of Inner Mongolia grasslands. We presume that other driving forces, such as changes in nongrazing‐resultant wind erosion and atmospheric nitrogen deposition, might have played a role albeit their effects need to be further examined.
Plasma Waves Causing Relativistic Electron Precipitation Events at International Space Station: Lessons From Conjunction Observations With Arase Satellite
Authors: Kataoka Ryuho , Asaoka Yoichi , Torii Shoji , Nakahira Satoshi , Ueno Haruka , Miyake Shoko , Miyoshi Yoshizumi , Kurita Satoshi , Shoji Masafumi , Kasahara Yoshiya , Ozaki Mitsunori , Matsuda Shoya , Matsuoka Ayako , Kasaba Yasumasa , Shinohara Iku , Hosokawa Keisuke , Uchida Herbert Akihito , Murase Kiyoka , Tanaka Yoshimasa
Published: August 2020

We report three different types of relativistic electron precipitation (REP) events observed at International Space Station (ISS), associated with electromagnetic ion cyclotron (EMIC) waves or whistler mode waves as observed by the Arase satellite at conjugate locations near the magnetic equator. Three different detectors installed on the ISS were complementarily used; CALET/CHD as the detector of precipitating MeV electrons, MAXI/RBM as the detector of sub‐MeV electrons from horizontal and vertical directions, and SEDA‐AP/SDOM to quantitatively measure the energy spectrum. The REP event on 21 August 2017 shows a quasiperiodic intensity variation at ~1 Hz which corresponds to variations of the EMIC waves at the Arase altitudes. The REP event on 24 April 2017 shows rapid and irregular intensity variation which corresponds to the amplitude variation of chorus waves, while the REP events on 26 October 2017 shows a smooth quasiperiodic time variation at ~0.2 Hz which corresponds to the amplitude variation of “electrostatic” whistler mode waves. This study clearly demonstrates that the time variation of REP events at ISS are caused by various types of plasma waves near the magnetic equator.
The Physical Mechanisms for the Sunrise Enhancement of Equatorial Ionospheric Upward Vertical Drifts
Authors: Chen Junjie , Wang Wenbin , Lei Jiuhou , Dang Tong
Published: August 2020

Satellite and incoherent scatter radar observations have shown frequently a strong enhancement of upward vertical E × B drifts in the equatorial ionospheric F region near sunrise. Previous studies suggested that this enhancement is associated with the local equatorial wind dynamo, the same process used to explain the prereversal enhancement after sunset. However, this hypothesis has never been tested in a first‐principles way. In this study, we explore the physical mechanisms responsible for the sunrise enhancement of equatorial upward vertical drifts using the Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model. The model well reproduces the sunrise enhancement of upward vertical drifts observed at Jicamarca on 10 June 2004. The simulation results show that large eastward zonal electric fields occur around sunrise at all latitudes but with a peak at middle latitudes. Further numerical experiments reveal that the equatorial sunrise enhancement at solar minimum is primarily driven by the E region zonal wind dynamo at middle latitudes rather than by the local dynamo effect in the equatorial region. Specifically, the intensity of the equatorial eastward electric field near sunrise is determined by the magnitudes of westward wind and its longitudinal gradient at middle latitudes and the declination of the dawn termination.
Observations of Anomalous Charge Structures in Supercell Thunderstorms in the Southeastern United States
Authors: Stough Sarah M. , Carey Lawrence D.
Published: August 2020

Anomalous thunderstorm charge structures (ACSs), characterized by a dominant layer of positive charge in the lower mixed‐phase region, are uncommon and rarely reported outside of the Great Plains region of the United States. This study documents the kinematics, precipitation microphysics, and charge structures of two supercell thunderstorms exhibiting ACSs that were observed in the Southeastern United States. Ground‐based three‐dimensional total lightning observations, polarimetric Doppler radar observations, and environmental model analysis of these supercells presented the opportunity to evaluate conceptual models of ACS development and characteristics in an atypical parameter space. In both anomalous storms, prominent layers of positive charge were located in lower to middle mixed‐phase regions (−10°C to −30°C) of updrafts and were spatially associated with riming hydrometeor types. Simultaneously, negative charge regions were identified above the primary positive charge layers in the upper mixed‐phase and glaciated region of updrafts, collocated with graupel and small ice hydrometeors. While coarse charge structure observations were consistent with noninductive charging‐based models of anomalous storms, charge structure complexities were also observed that suggested variability in cloud microphysical conditions. Analysis of the environments in which these storms formed indicated that several parameters thought to increase mixed‐phase liquid water content in favor of anomalous charging were inconsistent with those documented in the Great Plains region. However, environmental humidity metrics were most comparable. Comparisons between these and other documented anomalous storms identified similarities in kinematic structure and microphysical conditions while motivating ongoing study of the environmental parameter space supportive of ACSs.
The Unique Characteristics and Potential Mechanisms of the MJO‐QBO Relationship
Authors: Sakaeda Naoko , Dias Juliana , Kiladis George N.
Published: August 2020

Previous studies have shown that Madden‐Julian oscillation (MJO) convective activity increases when quasi‐biennial oscillation (QBO) easterlies appear in the lower stratosphere, and that this relationship is seen only during boreal winter. However, the physical mechanism behind this relationship is not fully understood. Building upon previous literature on the MJO‐QBO relationship, this study first tests whether the relationship between the QBO and MJO extends to other modes of organized tropical convection. Our analysis shows that the QBO does not have any significant relationship with other modes of variability such as convectively coupled equatorial waves (CCEWs). An extended analysis for periods prior to 1979 also shows that the boreal winter QBO‐MJO relationship substantially weakens prior to 1979. These results imply that, in addition to the seasonal dependence, any proposed mechanisms for the relationship between the QBO and MJO must be able to explain the uniqueness of this relationship with respect to other CCEWs, as well as the reason for its strengthening after 1979. Among the analyzed modes of tropical convection, the MJO is the most sensitive to the modulation of high cloud fraction and associated radiative feedback by the QBO and this sensitivity may weaken prior to 1979. These results indicate that the strong top‐heaviness of vertical motion and cloud‐radiative feedback associated with the MJO are important to explain its unique relationship with the QBO.
Mediterranean Overflow Over the Last 250 kyr: Freshwater Forcing From the Tropics to the Ice Sheets
Authors: Sierro Francisco J. , Hodell David A. , Andersen Nils , Azibeiro Lucia A. , Jimenez‐Espejo Francisco J. , Bahr André , Flores Jose Abel , Ausin Blanca , Rogerson Mike , Lozano‐Luz Rocio , Lebreiro Susana M. , Hernandez‐Molina Francisco Javier
Published: August 2020

To investigate past changes in the Mediterranean Overflow Water (MOW) to the Atlantic, we analyzed the strength of the MOW and benthic δ13C along the last 250 kyr at Integrated Ocean Drilling Program (IODP) Site U1389 in the Gulf of Cadiz, near the Strait of Gibraltar. Both the strength of the MOW and the benthic δ13C were mainly driven by precession‐controlled fluctuations in the Mediterranean hydrologic budget. Reduced/enhanced Nile discharge and lower/higher Mediterranean annual rainfall at precession maxima/minima resulted in higher/lower MOW strengths at Gibraltar and stronger/weaker Mediterranean overturning circulation. At millennial scale, the higher heat and freshwater loss to the atmosphere during Greenland stadials increased buoyancy loss in the eastern Mediterranean. This enhanced the density gradient with Atlantic water, resulting in a higher MOW velocity in the Gulf of Cadiz. Unlike non‐Heinrich stadials, a lower‐amplitude increase in velocity was seen during Heinrich stadials (HSs), and a significant drop in velocity was recorded in the middle phase. This weak MOW was especially recognized in Termination I and II during HS1 and HS11. These lower velocities at the depth of Site U1389 were triggered by MOW deepening due to the lower densities of Atlantic intermediate water caused by freshwater released from the Laurentide and Eurasian ice sheets. The intrusion of salt and heat at deeper depths in the Atlantic during HSs and its shoaling at the end could have contributed to drive the changes in the Atlantic Meridional Overturning Circulation during Terminations.
New Timing and Depth Constraints for the Catalina Metamorphic Core Complex, Southeast Arizona
Authors: Ducea Mihai N. , Triantafyllou Antoine , Krcmaric Jordan
Published: August 2020

The Santa Catalina‐Tortolita‐Rincon Mountains of Southeast Arizona are a classic metamorphic core complex (MCC) and represent footwall exposures of crustal rocks exhumed by a detachment system. This study presents new evidence for the formation of the majority of ductile deformation during the Eocene (~46 Ma), synchronous with the emplacement of the regionally significant Wilderness Sills Suite (57–45 Ma). The evidence is provided by Eocene U‐Pb ages of syn‐ to late kinematic dikes emplaced in the principal ductile mylonitic fabric of the Catalina forerange, earlier than the brittle normal fault system and the formation of Tucson basin beginning with the latest Oligocene. Well‐documented shear sense indicators may not reflect extension at that time (Eocene), but more likely the direction of crustal flow now rotated during later extension. Muscovite‐plagioclase Rb‐Sr isochron ages of three mylonitic rocks are all clustered around 34 Ma, which is inferred to be the last age when these rocks were being deformed under ductile conditions following the emplacement of the Wilderness Sills Suite and various related dikes. Biotite‐plagioclase Rb‐Sr ages on the same rocks demonstrate that the section cooled below ~300°C at 25–26 Ma during the development of normal faulting. Normal faulting was synchronous with the emplacement of the Catalina Intrusive Suite. New U‐Pb age results for Catalina Intrusive Suite indicate a combined mean age of 24.9 Ma. Chemical compositions of hornblende‐plagioclase pairs were obtained on six Catalina Intrusive Suite samples; depth estimates for the emplacement of the Catalina Intrusive Suite average of about 6 km. These results suggest that the exposed Catalina ductile detachment system was at about 5 km beneath the surface at 25 Ma. These new data bring new light into the development of this core complex and suggest that the similarity in orientations of principal ductile and brittle fabrics at the Catalina MCC locality are coincidental. Neither was the principal ductile fabric developed during the low‐angle normal faulting of the latest Oligocene nor was this exposed section a midcrustal one at that time. Transient, pluton emplacement‐enhanced, and extension‐related ductile deformation at shallow crustal levels operated locally at ~25 Ma but that does not account for the development of the majority of the Catalina MCC mylonites.
Transport and Retention of Sulfidized Silver Nanoparticles in Porous Media: The Role of Air‐Water Interfaces, Flow Velocity, and Natural Organic Matter
Authors: Leuther Frederic , Köhne John Maximilian , Metreveli George , Vogel Hans‐Jörg
Published: August 2020

The sulfidation and aging of silver nanoparticles (Ag‐NPs) with natural organic matter (NOM) are major transformation processes along their pathway in wastewater treatment plants and surface waters. Although soils appear to be a sink for disposed Ag‐NPs, the impact of variable saturation on the transport and retention behavior in porous media is still not fully understood. We studied the behavior of sulfidized silver nanoparticles (S‐Ag‐NPs, 1 mg L−1) in saturated and unsaturated sand columns regarding the effects of (i) the presence of NOM (5 mg L−1) in the aquatic phase on retention, transport, and remobilization of S‐Ag‐NPs and (ii) the distribution and quantity of air‐water and solid‐water interfaces for different flow velocities determined via X‐ray microtomography (X‐ray μCT). Unsaturated transport experiments were conducted under controlled conditions with unit gradients in water potential and constant water content along the flow direction for each applied flux. It was shown that (i) NOM in S‐Ag‐NP dispersion highly increased the NP‐mobility; (ii) differences between saturated and unsaturated transport were increasing with decreasing flux and, consequently, decreasing water contents; (iii) both, solid‐water and air‐water interfaces were involved in retention of S‐Ag‐NPs aged by NOM. Using numerical model simulations and X‐ray μCT of flow experiments, the breakthrough of Ag‐NP could be explained by a disproportional increase in air‐water interfaces and an increasing attachment efficiency with decreasing water content and flow velocity.
An Analytical Method to Calculate Groundwater Released From an Aquitard Undergoing Nonlinear Consolidation
Authors: Luo Huan , Li Zhaofeng , Luo Maolin , Zhang Qiang , Illman Walter A.
Published: August 2020

The estimation of groundwater released from aquitards is important for the groundwater resource management. In this study, a governing equation of drawdown variation within the aquitard, which undergoes nonlinear consolidation, was obtained based on the consolidation theory of Gibson et al. (1967, https://doi.org/10.1680/geot.1967.17.3.261). Then, analytical solutions of drawdown variations within an aquitard were derived for a single aquifer underlying an aquitard, as well as for the case when there are aquifers above and below an aquitard. Drawdown solutions were obtained for both the cases when there was a sudden hydraulic head decline in the confined aquifer(s). The characteristics of the groundwater dynamics and water balance in the aquitard have been analyzed with the analytical solution. A laboratory experiment was conducted to verify the analytical solution, and a type‐curve fitting method was presented to calculate the aquitard's hydraulic parameters. Our study revealed that the cumulative water released from the aquitard predicted by Gibson's theory (1967) is less than that obtained through Terzaghi's theory (1943). Groundwater released from the aquitard increases with increasing compression index, aquitard thickness, and drawdown of the adjacent aquifer, and with decreasing initial void ratio and initial effective stress. The time for the drawdown to reach steady state increases with increasing compression index, initial void ratio, and aquitard thickness, and with decreasing initial effective stress and hydraulic conductivity.
Application of Parameter Screening to Derive Optimal Initial State Adjustments for Streamflow Forecasting
Authors: Mai Juliane , Arsenault Richard , Tolson Bryan A. , Latraverse Marco , Demeester Kenjy
Published: August 2020

Streamflow forecasting is essential in many applications, including the management of hydropower reservoirs and of flood risks. To increase the performance of these hydrologic forecasts, a hydrological model is typically updated with optimal initial model states. These states are usually selected a priori and adjusted to obtain the optimal initial setup. The model states to adjust are generally selected by experts with deep knowledge of the model's behavior. These relationships are rarely documented and formalized, leading to difficulties in reproducibility and transferability to other models. The method here provides a fully automatized system to find the model states based on the parameter‐free sensitivity method of efficient elementary effects (EEE), which identifies the most informative variables of the hydrologic model CEQUEAU. The analysis is applied to 1,826 model setups for four Canadian basins. The identified states are formalized using clustering techniques to obtain adjustment “recipes” conditioned on given meteorological conditions. Several recipes are tested and compared to expert‐based recipes. The recipes are tested according to their ability to (a) obtain optimal initial states and (b) their forecast performance. The results show that (1) the EEE‐based recipes perform similarly or better than the expert‐based recipes in both objectives; (2) the recipes are similar across the four basins, highlighting their potential of spatial transferability; and (3) the adjustment of hydrologic model inputs significantly decreases forecast performance. The proposed approach to use EEE‐based recipes to obtain optimal initial states for forecasting is reproducible, objective, and suitable to be applied to other models and basins.
Excess Air Correction of SF6 and Other Dissolved Gases in Groundwater Impacted by Compressed Air From Drilling or Well Development
Authors: Poulsen David L. , Cook Peter G. , Dogramaci Shawan
Published: August 2020

Atmospheric gases that dissolve in groundwater at the time of recharge are valuable tracers of groundwater residence time, but corrections are sometimes required. Low‐solubility gases like SF6 are particularly susceptible to the effects of excess air, which is generally assumed to occur at the time of recharge. If after excess air correction SF6 is still elevated above the expected concentration for water in equilibrium with the atmosphere, this is often attributed to a terrigenic source. We propose that compressed air used during and after well installation is a potential source of excess air, which can sometimes explain elevated SF6 concentrations from wells drilled in the last few decades. This concept is demonstrated by correcting elevated SF6 and CFC‐12 measurements from 55 wells at field sites in the Pilbara region of Western Australia with up to 10 mL(STP)/kg of atmospheric air from the time of drilling (2006–2016). The resulting SF6 and CFC‐12 concentrations are consistent with recharge between 1950 and 1970 for most wells. Excess air in recharge from that period could not have contained enough SF6 to explain the measured concentrations. This decoupling of excess air from recharge is potentially also significant for other gaseous age tracers with limited solubility including SF5CF3, Halon 1301, 39Ar, 85Kr, and 81Kr.
l-DOPA and consolidation of fear extinction learning among women with posttraumatic stress disorder
Authors: Cisler Josh M. , Privratsky Anthony A. , Sartin-Tarm Anneliis , Sellnow Kyrie , Ross Marisa , Weaver Shelby , Hahn Emily , Herringa Ryan J. , James George Andrew , Kilts Clinton D.
Published: August 2020

This study tested whether l-DOPA delivered during the consolidation window following fear extinction learning reduces subsequent fear responding among women with PTSD. Adult women diagnosed with PTSD completed a contextual fear acquisition and extinction task during fMRI and then immediately received either placebo (n = 34), 100/25 mg l-DOPA/carbidopa (n = 28), or 200/50 mg l-DOPA/carbidopa (n = 29). Participants completed a resting-state scan before the task and again 45 min following drug ingestion to characterize effects of l-DOPA on extinction memory neural reactivation patterns during consolidation. Twenty-four hours later, participants returned for tests of context renewal, extinction recall, and reinstatement during fMRI with concurrent skin conductance responding (SCR) assessment. Both active drug groups demonstrated increased reactivation of extinction encoding in the amygdala during the post-task resting-state scan. For SCR data, both drug groups exhibited decreased Day 2 reinstatement across all stimuli compared to placebo, and there was some evidence for decreased context renewal to the fear stimulus in the 100 mg group compared to placebo. For imaging data, both drug groups demonstrated decreased Day 2 reinstatement across stimuli in a bilateral insula network compared to placebo. There was no evidence in SCR or neural activity that l-DOPA improved extinction recall. Reactivation of extinction encodings in the amygdala during consolidation on Day 1 predicted Day 2 activation of the insula network. These results support a role for dopamine during the consolidation window in boosting reactivation of amygdala extinction encodings and reducing reinstatement, but not improving extinction recall, in women with PTSD.
Triggering a switch from basal- to luminal-like breast cancer subtype by the small-molecule diptoindonesin G via induction of GABARAPL1
Authors: Fan Minmin , Chen Jingwei , Gao Jian , Xue Wenwen , Wang Yixuan , Li Wuhao , Zhou Lin , Li Xin , Jiang Chengfei , Sun Yang , Wu Xuefeng , Wu Xudong , Ge Huiming , Shen Yan , Xu Qiang
Published: August 2020

Breast cancer is a heterogeneous disease that includes different molecular subtypes. The basal-like subtype has a poor prognosis and a high recurrence rate, whereas the luminal-like subtype confers a more favorable patient prognosis partially due to anti-hormone therapy responsiveness. Here, we demonstrate that diptoindonesin G (Dip G), a natural product, exhibits robust differentiation-inducing activity in basal-like breast cancer cell lines and animal models. Specifically, Dip G treatment caused a partial transcriptome shift from basal to luminal gene expression signatures and prompted sensitization of basal-like breast tumors to tamoxifen therapy. Dip G upregulated the expression of both GABARAPL1 (GABAA receptor-associated protein-like 1) and ERβ. We revealed a previously unappreciated role of GABARAPL1 as a regulator in the specification of breast cancer subtypes that is dependent on ERβ levels. Our findings shed light on new therapeutic opportunities for basal-like breast cancer via a phenotype switch and indicate that Dip G may serve as a leading compound for the therapy of basal-like breast cancer.
Sequential combinations of chemotherapeutic agents with BH3 mimetics to treat rhabdomyosarcoma and avoid resistance
Authors: Alcon Clara , Manzano-Muñoz Albert , Prada Estela , Mora Jaume , Soriano Aroa , Guillén Gabriela , Gallego Soledad , Roma Josep , Samitier Josep , Villanueva Alberto , Montero Joan
Published: August 2020

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in childhood and adolescence. Refractory/relapsed RMS patients present a bad prognosis that combined with the lack of specific biomarkers impairs the development of new therapies. Here, we utilize dynamic BH3 profiling (DBP), a functional predictive biomarker that measures net changes in mitochondrial apoptotic signaling, to identify anti-apoptotic adaptations upon treatment. We employ this information to guide the use of BH3 mimetics to specifically inhibit BCL-2 pro-survival proteins, defeat resistance and avoid relapse. Indeed, we found that BH3 mimetics that selectively target anti-apoptotic BCL-xL and MCL-1, synergistically enhance the effect of clinically used chemotherapeutic agents vincristine and doxorubicin in RMS cells. We validated this strategy in vivo using a RMS patient-derived xenograft model and observed a reduction in tumor growth with a tendency to stabilization with the sequential combination of vincristine and the MCL-1 inhibitor S63845. We identified the molecular mechanism by which RMS cells acquire resistance to vincristine: an enhanced binding of BID and BAK to MCL-1 after drug exposure, which is suppressed by subsequently adding S63845. Our findings validate the use of DBP as a functional assay to predict treatment effectiveness in RMS and provide a rationale for combining BH3 mimetics with chemotherapeutic agents to avoid tumor resistance, improve treatment efficiency, and decrease undesired secondary effects.
Deubiquitination of CD36 by UCHL1 promotes foam cell formation
Authors: Xia Xiaohong , Xu Qiong , Liu Mingke , Chen Xuke , Liu Xiaolin , He Jinchan , Hu Tumei , Yu Cuifu , Huang Hongbiao , Liu Shiming , Liu Ningning
Published: August 2020

Atherosclerosis-associated cardiovascular diseases are main causes leading to high mortality worldwide. Macrophage-derived foam cell formation via uptaking modified lipoproteins is the initial and core step in the process of atherosclerosis. Meanwhile, scavenger receptor is indispensable for the formation of foam cells. UCHL1, a deubiquitinase, has been widely studied in multiple cancers. UCHL1 could be an oncogene or a tumor suppressor in dependent of tumor types. It remains unknown whether UCHL1 influences cellular oxLDL uptake. Herein we show that UCHL1 deletion significantly inhibits lipid accumulation and foam cell formation. Subsequently, we found that UCHL1 inhibitor or siRNA downregulates the expression of CD36 protein whereas SR-A, ABCA1, ABCG1, Lox-1, and SR-B1 have no significant change. Furthermore, the treatment of UCHL1 inhibition increases the abundance of K48-polyubiquitin on CD36 and the suppression of lipid uptake induced by UCHL1 deficiency is attenuated by blocking CD36 activation. Our study concluded that UCHL1 deletion decreases foam cell formation by promoting the degradation of CD36 protein, indicating UCHL1 may be a potential target for atherosclerosis treatment.
LncRNA TTN-AS1 promotes the progression of cholangiocarcinoma via the miR-320a/neuropilin-1 axis
Authors: Zhu Huaqiang , Zhai Bo , He Changjun , Li Ziyi , Gao Hengjun , Niu Zheyu , Jiang Xian , Lu Jun , Sun Xueying
Published: August 2020

Neuropilin-1 regulated by miR-320a participates in the progression of cholangiocarcinoma by serving as a co-receptor that activates multiple signaling pathways. The present study sought to investigate upstream lncRNAs that control the expression of miR-320a/neuropilin-1 axis and dissect some of the underlying mechanisms. Here we report lncRNA TTN-AS1 (titin-antisense RNA1) acts as a sponging ceRNA to downregulate miR-320a and is highly expressed in human cholangiocarcinoma tissues and cells. The expression of the above three molecules is correlated with the clinicopathologic parameters of cholangiocarcinoma patients. In this study, multiple bioinformatics tools and databases were employed to seek potential lncRNAs that have binding sites with miR-320a and TTN-AS1 was identified because it exhibited the largest folds of alteration between cholangiocarcinoma and normal bile duct epithelial cells. The regulatory role of TTN-AS1 on miR-320a was further evaluated by luciferase reporter and RNA pulldown assays, coupled with in situ hybridization and RNA immunoprecipitation analyses, which showed that TTN-AS1 bound to miR-320a through an argonaute2-dependent RNA interference pathway in the cytoplasm of cholangiocarcinoma cells. Knockdown and overexpression assays showed that the regulatory effect between TTN-AS1 and miR-320 was in a one-way manner. TTN-AS1 promoted the proliferation and migration of cholangiocarcinoma cells via the miR-320a/ neuropilin-1 axis. The function of TTN-AS1 on tumor growth and its interaction with miR-320a were confirmed in animal models. Further mechanistic studies revealed that TTA-AS1, through downregulating miR-320a, promoted cell cycle progression, epithelial–mesenchymal transition, and tumor angiogenesis by upregulating neuropilin-1, which co-interacted with the hepatocyte growth factor/c-Met and transforming growth factor (TGF)-β/TGF-β receptor I pathways. In conclusion, the present results demonstrate that lncRNA TTA-AS1 is a sponging ceRNA for miR-320a, which in turn downregulates neuropilin-1 in cholangiocarcinoma cells, indicating these three molecules represent potential biomarkers and therapeutic targets in the management of cholangiocarcinoma.
Selective detection of phospholipids in human blood plasma and single cells for cancer differentiation using dispersed solid-phase microextraction combined with extractive electrospray ionization mass spectrometry
Authors: Zhang Hua , Lu Haiyan , Huang Keke , Li Jiajia , Wei Feng , Liu Aiying , Chingin Konstantin , Chen Huanwen
Published: August 2020

Rapid and selective determination of phospholipids in microvolume biofluid samples for cancer differentiation was achieved by d-SPME–iEESI-MS.
Theoretical study on the absorption of carbon dioxide by DBU-based ionic liquids
Authors: Izadyar Mohammad , Rezaeian Mojtaba , Victorov Alexey
Published: August 2020

DBU-based ionic liquids with imidazole anions are a new generation of green solvents for CO2absorption.
Aminolysis of bis[bis(trimethylsilyl)amido]-manganese, -iron, and -cobalt for the synthesis of mono- and bis-silylene complexes
Authors: He Zhiyuan , Xue Xiaolian , Liu Yilan , Yu Na , Krogman Jeremy P.
Published: August 2020

Mono- and bis-silylene metal complexes may be synthesized in high yield from M{N(SiMe3)2}2 and PhC(NtBu)2SiHCl2.
Ru(ii)/diclofenac-based complexes: DNA, BSA interaction and their anticancer evaluation against lung and breast tumor cells
Authors: Oliveira Katia M. , Honorato João , Gonçalves Guilherme R. , Cominetti Marcia R. , Batista Alzir A. , Correa Rodrigo S.
Published: August 2020

The well-known anti-inflammatory drug diclofenac can form new ruthenium compounds with promising anti-tumor properties.
Two-dimensional polar metal of a PbTe monolayer by electrostatic doping
Authors: Xu Tao , Zhang Jingtong , Zhu Yuquan , Wang Jie , Shimada Takahiro , Kitamura Takayuki , Zhang Tong-Yi
Published: August 2020

A PbTe monolayer is predicted to possess intrinsic ferroelectricity whose polar distortions can coexist with doped electrons/holes exhibiting unusual polar metallicity.
Acid-directed morphology control of molybdenum carbide embedded in a nitrogen doped carbon matrix for enhanced electrocatalytic hydrogen evolution
Authors: Wang Jing , Li Siwei , Hu Jing , Niu Siqi , Li Yuzhi , Xu Ping
Published: August 2020

By an acid-directed strategy, β-Mo2C nanomaterials embedded in a nitrogen doped carbon matrix (β-Mo2C/NC) with controlled morphology are synthesized and exhibit outstanding HER activities in both acidic and alkaline solutions.
A supercapacitor with ultrahigh volumetric capacitance produced by self-assembly of reduced graphene oxide through phosphoric acid treatment
Authors: Liu Zhaoyuan , Wang Lidong , Ma Guizhi , Yuan Yinan , Jia Henan , Fei Weidong
Published: August 2020

Self-assembled reduced graphene oxide was prepared by a phosphoric acid heat-treatment method and exhibited an ultra-high volumetric capacitance.
Rising from the horizon: three-dimensional functional architectures assembled with MXene nanosheets
Authors: Song Fei , Li Guohao , Zhu Yisong , Wu Zhenjun , Xie Xiuqiang , Zhang Nan
Published: August 2020

The assembly methods, application prospects and existing problems of 3D MXene-based architectures are discussed.
Micro-scale spatial location engineering of COF–TiO2 heterojunctions for visible light driven photocatalytic alcohol oxidation
Authors: Li He , Liu Haoran , Li Chunzhi , Liu Jiali , Liu Jian , Yang Qihua
Published: August 2020

COF and TiO2 core–shell structured heterojunctions with the spatial location of two semiconductors either in the core or on the shell are precisely designed.
Topologically distributed one-dimensional TiO2 nanofillers maximize the dielectric energy density in a P(VDF-HFP) nanocomposite
Authors: Liu Xiaoru , Hu Penghao , Yu Jinyao , Fan Mingzhi , Ji Xumin , Sun Binzhou , Shen Yang
Published: August 2020

The dielectric energy density of a P(VDF-HFP) nanocomposite is greatly enhanced via the use of one-dimensional TiO2 nanofillers with a topological distribution.
Two-dimensional semiconducting covalent organic nanosheets for highly sensitive and stable NO2 sensing under humid conditions
Authors: Ko Woo Chul , Kim Min-Sung , Kwon Yong Jung , Jeong Jeehun , Kim Won Rae , Choi Hyeunseok , Park Jin Kuen , Jeong Young Kyu
Published: August 2020

A NO2 gas sensor integrated with two-dimensional covalent organic nanosheets shows highly sensitive and reliable NO2 sensing performance even at relatively high humidity levels. The excellent water-repelling ability originates from the superhydrophobic nature of CON surfaces.
A 3D topological Dirac semimetal/MoO3 thin film heterojunction infrared photodetector with a current reversal phenomenon
Authors: Yang Ming , Yang Yunkun , Liu Qi , Zhou Hongxi , Han Jiayue , Xie Xiaoyi , Xiu Faxian , Gou Jun , Wu Zhiming , Hu Zehua , Yu Ting , Wang Jun , Jiang Yadong
Published: August 2020

Photoelectric detection technology is extremely significant on account of its extensive applications in commercial and military fields, but high-performance array photodetectors based on Dirac semimetal thin film materials are rarely reported.
Interactive facial animation with deep neural networks
Authors: Paier Wolfgang , Hilsmann Anna , Eisert Peter
Published: August 2020

Creating realistic animations of human faces is still a challenging task in computer graphics. While computer graphics (CG) models capture much variability in a small parameter vector, they usually do not meet the necessary visual quality. This is due to the fact, that geometry‐based animation often does not allow fine‐grained deformations and fails in difficult areas (mouth, eyes) to produce realistic renderings. Image‐based animation techniques avoid these problems by using dynamic textures that capture details and small movements that are not explained by geometry. This comes at the cost of high‐memory requirements and limited flexibility in terms of animation because dynamic texture sequences need to be concatenated seamlessly, which is not always possible and prone to visual artefacts. In this study, the authors present a new hybrid animation framework that exploits recent advances in deep learning to provide an interactive animation engine that can be used via a simple and intuitive visualisation for facial expression editing. The authors describe an automatic pipeline to generate training sequences that consist of dynamic textures plus sequences of consistent three‐dimensional face models. Based on this data, they train a variational autoencoder to learn a low‐dimensional latent space of facial expressions that is used for interactive facial animation.
Water worlds in N-body simulations with fragmentation in systems without gaseous giants
Authors: Dugaro A. , de Elía G. C. , Darriba L. A.
Published: August 2020

Aims. We analyze the formation and evolution of terrestrial-like planets around solar-type stars in the absence of gaseous giants. In particular, we focus on the physical and dynamical properties of those that survive in the system’s habitable zone (HZ). This investigation is based on a comparative study between N-body simulations that include fragmentation and others that consider all collisions as perfect mergers.

Methods. We use an N-body code, presented in a previous paper, that allows planetary fragmentation. We carry out three sets of 24 simulations for 400 Myr. Two sets are developed adopting a model that includes hit-and-run collisions and planetary fragmentation, each one with different values of the individual minimum mass allowed for the fragments. For the third set, we considered that all collisions lead to perfect mergers.

Results. The planetary systems produced in N-body simulations with and without fragmentation are broadly similar, though with some differences. In simulations with fragmentation, the formed planets have lower masses since part of them is distributed among collisional fragments. Additionally, those planets presented lower eccentricities, presumably due to dynamical friction with the generated fragments. Lastly, perfect mergers and hit-and-run collisions are the most common outcome. Regardless of the collisional treatment adopted, most of the planets that survive in the HZ start the simulation beyond the snow line, having very high final water contents. Such planets are called water worlds. The fragments’ contribution to their final mass and water content is negligible. Finally, the individual minimum mass for fragments may play an important role in the planets’ collisional history.

Conclusions. Collisional models that incorporate fragmentation and hit-and-run collisions lead to a more detailed description of the physical properties of the terrestrial-like planets formed. We conclude that planetary fragmentation is not a barrier to the formation of water worlds in the HZ. The results shown in this work suggest that further refinement is necessary to have a more realistic model of planetary formation.
Strömgren metallicities for intermediate-age and old star clusters
Authors: Piatti Andrés E.
Published: August 2020

We report results that show that the straightforward star cluster metallicities obtained from Strömgren vby photometry are age-dependent and need to be corrected for further use. This outcome arises from the comparison of [Fe/H] values derived from Strömgren photometry with those metallicities published in the literature for 26 Large and Small Magellanic Cloud star clusters, whose ages range from ∼1 Gyr up to the oldest-known globular cluster ages in these galaxies. While deriving mean star cluster metallicities, we carried out a thorough selection of red giant branch candidates to comply with the Strömgren metallicity calibration validity regime. We paid attention to the effect of contamination by field stars, particularly those that lie inside the star clusters’ radii, that are distributed along the star cluster red giant branches and that have [Fe/H] values covering a similar range as that for the selected stars. We find that the measured Strömgren metallicities are systematically more metal-poor than the published ones and that a quadratically age-varying function reproduces the relative metallicity values with an overall uncertainty of ∼0.05 dex. We finally performed a similar comparison relying on a fully independent approach, which consisted in using theoretical red giant branches of old globular clusters spanning [Fe/H] values from −2.0 up to 0.0 dex as standards. We then superimposed onto them the red giant branches of star clusters with ages in the range 1.0−12.5 Gyr and estimated their associated metallicities by interpolation. The derived theoretical relative metallicities follow a similar trend as a function of the star clusters’ ages as what has been found from observations of star clusters.