bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for Secondary Ice Production in Southern Ocean Maritime Boundary Layer Clouds
Authors: Järvinen Emma , McCluskey Christina S. , Waitz Fritz , Schnaiter Martin , Bansemer Aaron , Bardeen Charles G. , Gettelman Andrew , Heymsfield Andrew , Stith Jeffrey L. , Wu Wei , D’Alessandro John J. , McFarquhar Greg M. , Diao Minghui , Finlon Joseph A. , Hill Thomas C. J. , Levin Ezra J. T. , Moore Kathryn A. , DeMott Paul J.
Published: August 2022

Maritime boundary‐layer clouds over the Southern Ocean (SO) have a large shortwave radiative effect. Yet, climate models have difficulties in representing these clouds and, especially, their phase in this observationally sparse region. This study aims to increase the knowledge of SO cloud phase by presenting in‐situ cloud microphysical observations from the Southern Ocean Clouds, Radiation, Aerosol, Transport Experimental Study (SOCRATES). We investigate the occurrence of ice in summertime marine stratocumulus and cumulus clouds in the temperature range between 6 and −25°C. Our observations show that in ice‐containing clouds, maximum ice number concentrations of up to several hundreds per liter were found. The observed ice crystal concentrations were on average one to two orders of magnitude higher than the simultaneously measured ice nucleating particle (INP) concentrations in the temperature range below −10°C and up to five orders of magnitude higher than estimated INP concentrations in the temperature range above −10°C. These results highlight the importance of secondary ice production (SIP) in SO summertime marine boundary‐layer clouds. Evidence for rime splintering was found in the Hallett‐Mossop (HM) temperature range but the exact SIP mechanism active at lower temperatures remains unclear. Finally, instrument simulators were used to assess simulated co‐located cloud ice concentrations and the role of modeled HM rime‐splintering. We found that CAM6 is deficient in simulating number concentrations across the HM temperature range with little sensitivity to the model HM process, which is inconsistent with the aforementioned observational evidence of highly active SIP processes in SO low‐level clouds.
A Non‐Parametric Circular Statistics‐Based Framework for Predicting Peakflow Seasonality at Ungauged Sites
Authors: Kalai Chingka , Mondal Arpita
Published: August 2022

Regional frequency analysis (RFA) serves as a useful tool for flood estimation at a regional level, to improve the precision of estimated flood quantiles or for prediction in ungauged basins. RFA is used extensively in hydrologic literature for estimation of the magnitude of the hydrologic variable (annual maximum flows), pooling data from several sites within a homogeneous region. However, in areas that experience a strong seasonality of the climate, the timing of a hazardous event, such as flood, may be equally important. Therefore, in such regions, improved estimation of annual peakflow seasonality is imperative for efficient management of water infrastructure or for undertaking timely preventive measures against floods. In this study, we propose a novel RFA framework for estimation of annual peakflow seasonality based on circular statistics. The framework consists of (a) selection of attributes based on catchment similarity using seasonality descriptors as a response, (b) formation of homogeneous regions based on the region of influence method, (c) homogeneity tests adapted to directional data on timing of annual peakflows, and (d) probabilistic prediction of annual peakflow seasonality using the non‐parametric regional circular density. Applicability of the proposed approach is first demonstrated on two synthetically generated homogeneous regions, with unimodal and bimodal annual peakflow seasonality, respectively. The proposed homogeneity test outperforms the existing test yielding H value < 1 for homogeneous regions. Further, real‐world applications are illustrated on prediction of flood peak timing in the Northwest USA, revealing nearly 75% of the sites with absolute bias <16 days.
The Future Climate and Air Quality Response From Different Near‐Term Climate Forcer, Climate, and Land‐Use Scenarios Using UKESM1
Authors: Turnock Steven T. , Allen Robert , Archibald Alex T. , Dalvi Mohit , Folberth Gerd , Griffiths Paul T. , Keeble James , Robertson Eddy , O’Connor Fiona M.
Published: August 2022

Near‐term climate forcers (NTCFs) can influence climate via interaction with the Earth's radiative balance and include both aerosols and trace gas constituents of the atmosphere (such as methane and ozone). Two of the principal NTCFs, aerosols (particulate matter) and tropospheric ozone (O3), can also affect local air quality when present in the lower levels of the atmosphere. Previous studies have shown that mitigation of NTCFs has the potential to improve air quality and reduce the rate of surface warming induced by long‐lived greenhouse gases. Here, we assess the combined air quality and climate impacts from changes in NTCFs under numerous different future mitigation scenarios, relative to a future reference scenario, that were conducted by a single Earth system model (UKESM1) as part of the Aerosol and Chemistry Model Intercomparison Project (AerChemMIP). Co‐benefits to both global air quality and climate are only achieved in the future scenario with strong mitigation measures applied to all NTCFs, particularly aerosols and methane, with penalties identified for inaction. When compared to the combined NTCF mitigation scenario, analysis of individual mitigation scenarios shows that there are important non‐linearities and interactions between NTCFs (e.g., aerosols and clouds). If only aerosol components are mitigated, there are still benefits to air quality but detrimental impacts on climate, particularly at the regional scale. In addition, other changes in future land‐use and climate could have important impacts on regional NTCFs, which should be considered when designing future mitigation measures to anthropogenic emissions.
Extratropical Climate Change During Periods Before and After an Arctic Ice‐Free Summer
Authors: Xie Yongkun , Nie Hanbin , He Yongli
Published: August 2022

The temperature of a well‐mixed ice‐water mixture stays constant until the ice melts due to external heat. Whether the temperature over the Arctic Ocean exhibits an analogous stagewise evolution to reach an ice‐free point remains unclear. Therefore, this study explored the characteristics of extratropical climate change before and after a period during which the Arctic Ocean was ice‐free in summer using multimodel simulations. Here, we show that the seasonality of Arctic warming varies between the two periods separated by an ice‐free summer. The warming maximum in the cold season delayed for a month after becoming ice‐free than before. In addition, the warming maximum lagged behind the sea‐ice decline maximum before becoming ice‐free, whereas the maximums of the two became coordinated after becoming ice‐free. The closed cross‐season energy cycle demonstrated that the capacitor effect of the Arctic Ocean with delayed release of the energy taken up in spring and summer due to sea‐ice decline and seawater absorption is crucial for the seasonality observed in Arctic climate change. Moreover, we found that although Arctic amplification induced general weakening in high‐frequency weather variability in the mid‐high latitudes via decreased meridional temperature gradients, significant weakening was induced only after becoming ice‐free under high emission. Our findings suggest that the two stages of Arctic sea‐ice decline should be taken into consideration when dealing with global warming.
Contrasting Sea‐Air CO2 Exchanges in the Western Tropical Atlantic Ocean
Authors: Monteiro Thiago , Batista Matheus , Henley Sian , Machado Eunice da Costa , Araujo Moacyr , Kerr Rodrigo
Published: August 2022

The western Tropical Atlantic Ocean is a biogeochemically complex region due to the structure of the surface current system and the large freshwater input from the Amazon River coupled with the dynamics of precipitation. Such features make it difficult to understand the dynamics of the carbon cycle, leading to contrasting estimates in sea‐air CO2 exchanges in this region. Here, we demonstrate that these contrasting estimates occur because the western Tropical Atlantic Ocean can be split into three distinct sub‐regions in terms of the sea‐air CO2 exchanges. The sub‐region under the North Brazil Current domain acts as a weak annual CO2 source to the atmosphere, with low interannual variability. The sub‐region under the North Equatorial Current influence acts as an annual CO2 sink, with great temporal variability. The third sub‐region under the Amazon River plume influence shows greater interannual variability of CO2 exchanges, but it always acts as a net oceanic sink for CO2. Despite this large spatial variability, the entire region acts as a net annual CO2 sink of −1.6 ± 1.0 mmol m−2 day−1. Importantly, the Amazon River plume waters drive 87% of the CO2 uptake in the western Tropical Atlantic Ocean. In addition, we found a significant increasing trend in sea surface CO2 partial pressure in the North Brazil Current and North Equatorial Current waters. Such trends are more pronounced than the increase in atmospheric CO2 partial pressure, revealing the sensitivity of carbon dynamics in these sub‐regions to global climate change.
Asthenospheric Flow From East Asia to the Philippine Sea Plate Revealed by Rj‐MCMC Inversion of Surface Waves
Authors: Zhao Yanzhe , Guo Zhen , Wang Yanbin
Published: August 2022

The Pacific and Philippine Sea Plate subductions have resulted in and controlled the development of a typical trench‐arc‐back‐arc system in NE Asia since the Cenozoic. The formation of widely distributed intraplate volcanoes and the dynamic pattern of the entire region are still debated. Here we constructed a three‐dimensional anisotropic S‐wave velocity model of NE Asia by inverting Rayleigh wave dispersion using a modified reversible‐jump Markov Chain Monte Carlo (rj‐MCMC) algorithm. The resulting model revealed a localized mantle upwelling beneath intraplate volcanoes in NE Asia and an ongoing lithospheric downwelling beneath the central Korean Peninsula. This suggests vigorous asthenosphere and lithosphere interactions, which is likely to control the spatial distribution of Cenozoic volcanoes. The fast directions show clockwise rotation beneath NE Asia, which eventually points to the Nankai Trough. This observation is broadly consistent with shear wave splitting and suggests the presence of mantle flow from East China to the Philippine Sea Plate. The slab window beneath the Nankai Trough within the Philippine Sea Plate subduction system may accommodate the mantle flow from East China. Our study indicates that the interaction of the Philippine, Pacific Sea Plates, and Eurasian Plates plays an essential role in controlling the mantle flow and intraplate volcanism of NE Asia.
Fluvial Sedimentary Response to Late Quaternary Climate and Tectonics at the Himalayan Frontal Thrust, Central Nepal
Authors: Hamahashi Mari , Hubbard Judith A. , Almeida Rafael V. , Haines Samuel H. , Owen Lewis A. , Mishra Sanjita , Sapkota Soma Nath
Published: August 2022

To investigate the subsurface structure surrounding the Main Frontal Thrust (MFT) in central Nepal, we drilled and cored sediments to depths of 45–100 m at 10 sites. Our boreholes were located along previously acquired high‐resolution seismic profiles across the MFT imaging the upper 1–2 km of the subsurface, which revealed a beveled erosional surface in the hanging wall above a broad, gentle anticline, as well as growth strata in the footwall. The boreholes exhibit interlayered clays, silts, sands, and gravels, dated with optically stimulated luminescence and radiocarbon to <72.5 ± 4.3 ka, with a transition from finer to coarser sediments at ∼13.5 ± 0.1 ka. Near the fault tip, the deposits exhibit steeper dips and deformation bands. A 25‐m‐thick section of silt and clay above the south end of the buried anticline is interpreted as a temporary lacustrine depocenter formed due to uplift near the fault tip. Based on the distribution of marker beds and sediment ages, we interpret a shortening rate of 3.1–12.1 m/ka on the MFT. Three major transitions between fluvial‐lacustrine and coarse fluvial channel facies are inferred from the boreholes, and the timings of these transitions correlate with Indian monsoonal intensity variations linked to Earth's precession. We infer that a strengthened monsoon led to increased river discharge and advance of coarse bedload‐dominant braided channels, whereas a weak monsoon formed a finer‐grained channel environment. These monsoonal climate variations have affected the depositional environment and river base levels in this region, influencing the formation and apparent relative uplift of nearby river terraces.
Evolution of the Northern Part of the Lesser Antilles Arc—Geochemical Constraints From St. Barthélemy Island Lavas
Authors: Bosch Delphine , Zami Fabienne , Philippon Mélody , Lebrun Jean‐Frédéric , Münch Philippe , Cornée Jean‐Jacques , Legendre Lucie , Lemoyne Alexandre
Published: August 2022

This study presents an extensive geochemical data set of 23 samples from St. Barthélemy Island, which belongs to the extinct branch of the Lesser Antilles arc and is currently exposed in the northern part of the subduction forearc. Samples were selected to represent all lithologies and main periods of magmatism, that is, Middle‐Late Eocene, Early Oligocene and Late Oligocene. They show enrichment in light rare earth element/medium rare earth element, large ion lithophile elements (Rb and Ba) and isotopic characteristics, suggesting mixing between the mantle and a subduction component (oceanic crust + sediments). Trace element ratios suggest that primary magmas were generated in a normal mid‐oceanic ridge basalt‐type mantle‐wedge that underwent 8%–18% partial melting in the spinel‐stability field. The sediment contribution was low (0.1%–1%) irrespective of the age of the samples. This is similar to what is observed for the northern Lesser Antilles active branch. St. Barthélemy Island shares strong similarities with St. Martin Island, located on the same extinct arc branch, which suggests a similar geodynamic evolution. Oligocene samples displayed an increase in incompatible elements in the magma source, suggesting an increase in sediment melts, which could be correlated with a drastic change in the tectonic regime at that time, characterized by stretching perpendicular to the trench and subsequent basin opening. On Δ7/4Pb versus206Pb/204Pb, the samples showed a similar trend for both active and extinct islands of the northern Lesser Antilles, suggesting negligible changes in the nature of the magma sources.
Polarization Characteristics of a Single Mode Radio Wave Traversing Through the Ionosphere: A Unique Observation From the RRI on ePOP/SWARM‐E
Authors: Pandey Kuldeep , Eyiguler E. C. Kalafatoglu , Gillies Robert G. , Hussey Glenn C. , Danskin Donald W. , Yau Andrew W.
Published: August 2022

The polarization characteristics of radio waves traversing the ionosphere can be determined using the cross‐dipole antennas of Radio Receiver Instrument (RRI) onboard the Enhanced Polar Outflow Probe payload on the CAScade, Smallsat, and Ionospheric Polar Explorer/Swarm‐E satellite. Numerous coordinated ground‐RRI transionospheric propagation experiments have been executed, with the present study using transmitted radio waves from a High Frequency (HF) ground transmitter located in Ottawa, Canada (45.41°N, 75.55°W). Most of these experiments have shown the HF radio waves to propagate with both magnetoionic propagation modes, the O‐ and X‐modes, combined. However, the coordinated ground‐RRI experiment on 12 May 2017 showed only one magnetoionic propagation mode. The observed polarization state had a stable orientation angle, but the ellipticity angle changed from −19° to linear (0°) and finally 30° within a latitude span of 15°. A detailed investigation using magnetoionic ray trace modeling and ground‐based ionogram observations revealed that the HF transmitted frequency and ionospheric conditions were such that only the O‐mode radio waves reached the satellite for the entire pass. This distinct observation is a unique opportunity to examine the radio wave polarization state during a transionospheric propagation of only O‐mode waves.
The Fate of Oxygen in the Ocean and Its Sensitivity to Local Changes in Biological Production
Authors: Holzer Mark
Published: August 2022

We investigate the sensitivity of the oxygen content and true oxygen utilization of key low‐oxygen regions Ω to pointwise changes in biological production. To understand how the combined water and biogenic particle transport controls the sensitivity patterns and the fate of oxygen in the ocean, we develop new relationships that link the steady‐state oxygen content and deficit of Ω to the downstream and upstream oxygen utilization rate (OUR), respectively. We find that the amount of oxygen from Ω that will be lost per unit volume at point r is linked to OUR(r) through the mean oxygen age accumulated in Ω. The geographic sensitivity pattern of the Ω‐integrated oxygen deficit is shaped by where the utilization occurs that causes this deficit. The contribution to the oxygen deficit of Ω from utilization at r is controlled by the mean time that water at r spends in Ω before next ventilation at the surface. We illustrate these relationships and the new transport timescales using a simple steady‐state data‐constrained carbon and oxygen model. We focus on Ω being the global ocean, the Pacific Hypoxic Zone (PHZ, [O2] < 62.5 µM), and the North Pacific oxygen minimum zone. The oxygen deficit of the PHZ is most sensitive where mode and intermediate waters form and where increased organic‐matter production directly increases the PHZ's oxygen demand. The fraction of the local oxygen concentration that will be utilized in respiration is as high as 90% in the PHZ and up to 70% in the water column beneath it.
Monitoring Surface 10Be/7Be Directly Reveals Stratospheric Air Intrusion in Sichuan Basin, China
Authors: Liu Xuke , Fu Yunchong , Bi Yanting , Zhang Li , Zhao Guoqing , Xian Feng , Zhou Weijian
Published: August 2022

Stratospheric air intrusion can break the balance of atmospheric properties such as chemicals and radiation affecting the atmosphere. The meteoric cosmogenic 7Be and 10Be are mainly produced between the lower stratosphere and the upper troposphere and then adsorbed on aerosols for transport, they are good tracers of the atmospheric mass transport. Here, 7Be and 10Be in aerosols were measured simultaneously by accelerator mass spectrometry, and after removing dust 10Be interference, daily resolution 7Be and 10Be for the whole year in Chengdu (a major city in the Sichuan Basin of China) was obtained. The long‐period tracing of stratospheric air intrusion in the Sichuan Basin area is realized by directly observing the surface 10Be/7Be ratio. This work confirms the influence of stratospheric air intrusion on the surface O3 and atmospheric water vapor in the Sichuan Basin and finds that the stratospheric air intrusion degree in spring and summer is significantly higher than that in autumn and winter. The results indicate that high‐resolution 10Be/7Be can provide effective and refined tracers for the atmospheric vertical motion. The new 7Be and 10Be observation records contribute to evaluating the impact on the environment and climate during the stratospheric air intrusion in the Sichuan Basin.
A Revision of the Formation Conditions of the Vredefort Crater
Authors: Allen Natalie H. , Nakajima Miki , Wünnemann Kai , Helhoski Søren , Trail Dustin
Published: August 2022

The Vredefort impact structure, located in South Africa and formed 2.02 Ga, is the largest confirmed remnant impact crater on Earth. The widely accepted impactor diameter and velocity to form this crater are 15 km and 15 km/s, respectively, which produce a crater diameter of 172 km. This is much smaller than the most commonly cited estimates (250–280 km), and while previous results were able to match the geologic evidence known at that time, these impact parameters are not consistent with more recent geological constraints. Here, we conduct impact simulations to model the Vredefort crater formation with the shock physics code impact Simplified Arbitrary Lagrangian Eulerian (iSALE). Our numerical simulations show that combinations of the impactor diameter and impact velocity of 25 km and 15 km/s or 20 km and 25 km/s are able to recreate the larger crater size of ∼250 km. Moreover, these configurations can reproduce shock‐metamorphic features present in the impact structure today, including the distributions of breccia, shatter cones, planar deformation features in quartz and zircon, and melt. Our model also predicts that Vredefort and Karelia, Russia, where an ejecta layer from the impact was found, were approximately 2,000–2,500 km apart based on the layer thickness. Additionally, we use this model to predict the potential global effects of such a large impact by estimating the amount of climatically important gases released to the atmosphere at the time. Our work demonstrates the need to revisit previously estimated impactor parameters for large terrestrial craters in order to better characterize impact events on Earth and elsewhere.
Hot Moments of N2O Emission Under Water and Nitrogen Management in Three Types of Steppe
Authors: Liu Wei , Lü Xiao‐Tao , Yang Yong , Hou Longyu , Shao Changliang , Yuan Wenping , Pan Qingmin , Li Linghao
Published: August 2022

Hot moments of soil nitrous oxide (N2O) emission contribute to large fractions of total annual emissions. Magnitudes of N2O emission during hot moments to increasing water and nitrogen (N) availabilities in different steppe types were not well understood. Based on soil monoliths collected from three steppes (meadow, typical, and desert steppes) in northern China, we found that the typical steppe held the lowest N2O emission among the three steppes. Water and N co‐addition could increase soil N2O emission by up to 245‐fold. Water addition significantly enhanced soil N2O emission in all the three steppes, but the sensitivity of soil N2O emission to water addition decreased from desert steppe (r2 = 0.83) to typical (r2 = 0.73) and meadow (r2 = 0.66) steppes. Nitrogen addition significantly promoted soil N2O emission only in the meadow steppe where soil C:N was relatively higher than the other two steppes. Water and N addition displayed strong positive interaction on soil N2O emission in the meadow steppe while negative interaction in the typical steppe. Different responses of plants, microorganisms and soil NO3− concentration drove the variation in magnitude of soil N2O emission between the two steppes. Our results illustrate different interactions of water and N addition on hot moments of soil N2O emission in the three steppes. We suggest that the pulsed feature of N2O emission should be taken into account in prediction of greenhouse gas emission in the global arid and semiarid grasslands.
A Tempered Particle Filter to Enhance the Assimilation of SAR‐Derived Flood Extent Maps Into Flood Forecasting Models
Authors: Di Mauro Concetta , Hostache Renaud , Matgen Patrick , Pelich Ramona , Chini Marco , van Leeuwen Peter Jan , Nichols Nancy , Blöschl Günter
Published: August 2022

Data assimilation (DA) is a powerful tool to optimally combine uncertain model simulations and observations. Among DA techniques, the particle filter (PF) has gained attention for its capacity to deal with nonlinear systems and for its relaxation of the Gaussian assumption. However, the PF may suffer from degeneracy and sample impoverishment. In this study, we propose an innovative approach, based on a tempered particle filter (TPF), aiming at mitigating PFs issues, thus extending over time the assimilation benefits. Probabilistic flood maps derived from synthetic aperture radar data are assimilated into a flood forecasting model through an iterative process including a particle mutation in order to keep diversity within the ensemble. Results show an improvement of the model forecasts accuracy, with respect to the Open Loop: on average the root mean square error (RMSE) of water levels decrease by 80% at the assimilation time and by 60% 2 days after the assimilation. A comparison with the Sequential Importance Sampling (SIS) is carried out showing that although SIS performances are generally comparable to the TPF ones at the assimilation time, they tend to decrease more quickly. For instance, on average TPF‐based RMSE are 20% lower compared to the SIS‐based ones 2 days after the assimilation. The application of the TPF determines higher critical success index values compared to the SIS. On average the increase in performances lasts for almost 3 days after the assimilation. Our study provides evidence that the application of the variant of the TPF enables more persistent benefits compared to the SIS.
Understanding the Hydrogeochemical Response of a Mountainous Watershed Using Integrated Surface‐Subsurface Flow and Reactive Transport Modeling
Authors: Xu Zexuan , Molins Sergi , Özgen‐Xian Ilhan , Dwivedi Dipankar , Svyatsky Daniil , Moulton J. David , Steefel Carl
Published: August 2022

Climate change and other disturbances significantly impact hydrogeochemical exports from mountainous headwater catchments such as the Upper Colorado River Basin. Developing a mechanistic understanding of how the physical and chemical processes interact in time and space in an integrated manner is key to quantifying the future impacts of such disturbances. The hydrogeochemical response of a mountainous catchment in the 2010–2019 period is evaluated quantitatively using a high‐resolution model that simulates integrated hydrology, and transport and reactions for selected solutes and minerals. The model assumes that pyrite is present only at depth while calcite is distributed uniformly, and captures the observed C‐Q reasonably well. Distinct C‐Q dynamics are observed in an average (WY16), a wet (WY17), and a dry (WY18) water year. The model also quantifies the water fraction from surface, shallow and deep groundwater compartments using tracers, and suggests greater groundwater contributions to peak stream discharge in the dry WY18. Results demonstrate that calcium concentrations do not change significantly from year to year, while sulfate shows significant temporal variability. Pyrite dissolution is affected by the changing hydrological drivers where it is enhanced in the dry WY18; calcite dissolution supplements calcium dilution under high flow conditions. The model simulates the reaction hotspots controlled by hydrological conditions, and the spatially‐resolved results show that higher soil saturation and less snowpack occur earlier on the south‐facing side than on the north‐facing side. This is a first‐of‐its‐kind demonstration of a model that integrates hydrologic processes, including evapotranspiration, and reactive transport to enable a predictive understanding of hydrogeochemical exports.
A one-step, tunable method of selective reactive sputter deposition as a wrinkling approach for silver/polydimethylsiloxane for electrically conductive pliable surfaces
Authors: Loh Joel Y. Y. , Zeineddine Ali , Shayegannia Moein , McNeil Robyn , McRae Liam , Kherani Nazir P.
Published: August 2022

The wrinkle period and morphology of a metal thin film on an elastic substrate is typically controlled by modifying the substrate before carrying out additional metal deposition steps. Herein, we show that a simultaneously selective and reactive sputtering plasma that modifies the surface of a polydimethylsiloxane (PDMS) substrate while not reacting with the metal during the deposition process decreases the wrinkle wavelength and induces additional wrinkling components and features such as ripples or folds. The selective reaction of the nitrogen plasma with PDMS functionalizes the siloxane surface into silicon oxynitride. This hardens the immediate surface of PDMS, with a quadratic increase in the Young’s modulus as a function of the sputtering flow ratio. The increase in the critical strain mismatch and the corresponding presence of folds in the nitrogen-modified wrinkled silver film form a suitable plasmonic platform for surface-enhanced Raman spectroscopy (SERS), yielding an enhancement factor of 4.8 × 105for detecting lipids. This enhancement is linked to the emergence of electromagnetic hotspots from surface plasmon polariton coupling between the folds/wrinkles, which in turn enables the detection of low concentrations of organics using SERS. Furthermore, when strained, the nitrogen-modified wrinkles enhance electrical conductivity by a factor of 12 compared with unmodified films. Finally, the optical properties of the substrate can be tuned by altering the N2content. The simple addition of nonreactive nitrogen to silver sputtering enables simultaneous PDMS hardening and growth of the silver film and together provide a new avenue for tuning wrinkling parameters and enhancing the electrical conductivity of pliable surfaces.
Methylation of HBP1 by PRMT1 promotes tumor progression by regulating actin cytoskeleton remodeling
Authors: Wang Jiyin , Yang Ruixiang , Cheng Yuning , Zhou Yue , Zhang Tongjia , Wang Shujie , Li Hui , Jiang Wei , Zhang Xiaowei
Published: August 2022

HBP1 is a sequence-specific transcription factor which generally considered as a crucial growth inhibitor. Posttranslational modification of HBP1 is vital for its function. In this study, we demonstrate that HBP1 is methylated at R378 by PRMT1, which decreases HBP1 protein stability by promoting its ubiquitination and proteasome-mediated degradation. PRMT1-mediated methylation of HBP1 alleviates the repressive effects of HBP1 on tumor metastasis and growth. GSN is identified as a novel target gene of HBP1. Methylation of HBP1 promotes actin cytoskeleton remodeling, glycolysis and tumor progression by downregulating GSN (a vital actin-binding protein) levels. The methylated HBP1-GSN axis is associated with the clinical outcomes of cancer patients. This investigation elucidates the mechanism of how methylated HBP1 facilitates actin cytoskeleton remodeling, thus attenuates its tumor-suppressive function and promotes tumor progression. Targeting methylated HBP1-GSN axis may provide a therapeutic strategy for cancer.
“Difficult” dental patients: a grounded theory study of dental staff’s experiences
Authors: Alvenfors Adam , Velic Mersiha , Marklund Bertil , Kylén Sven , Lingström Peter , Bernson Jenny
Published: August 2022

Introduction

The “difficult” patient is a well-known and potentially negative character in various care contexts.

Objectives

This study aimed to generate a conceptual framework explaining the main concerns about “difficult” dental patients, and obtain a deeper understanding of their characteristics, how they affect the dental staff and how the staff think and act in order to manage these patients.

Methods

Ten interviews were conducted with professional dental caregivers, including dentists, dental hygienists, and dental nurses. The audio-recorded interviews were transcribed and analyzed in accordance with the principles of grounded theory.

Results

The main concern regarding “difficult” dental patients generated a framework of seven descriptive interrelated lower-level categories grounded in the data, subsumed in the core category “balancing subjective difficulties”. The informants perceived the possession of “showing interaction difficulties” and “having bio-psycho-social complexity”, as characteristic features of “difficult” patients, who could further adversely affect the dental staff by “evoking negative emotions and behaviors”, “hampering self-esteem and job satisfaction”, and “impairing life and health in general”. To manage the dental care of these patients, the staff used strategies aimed at “activating internal and external resources” and “creating adaptive treatment relations” with patients.

Conclusions

The dental staff’s meaning of the phenomenon of “difficult” dental patients points to specific characteristics, effects, and handling strategies. The core category captures the contradictory dynamics of characteristics and affects as these concepts seem interrelated to the caregivers’ handling capacity. The dental staff’s possibility of handling the main concern through balancing subjective difficulties depends on contextual conditions regarding time, to bring the patient and/or oneself at the center of attention. This indicates a need for further research regarding dental interactions and studies generalizing the outlook on “difficult” dental patients.
OTUD1 deubiquitinase regulates NF-κB- and KEAP1-mediated inflammatory responses and reactive oxygen species-associated cell death pathways
Authors: Oikawa Daisuke , Gi Min , Kosako Hidetaka , Shimizu Kouhei , Takahashi Hirotaka , Shiota Masayuki , Hosomi Shuhei , Komakura Keidai , Wanibuchi Hideki , Tsuruta Daisuke , Sawasaki Tatsuya , Tokunaga Fuminori
Published: August 2022

Deubiquitinating enzymes (DUBs) regulate numerous cellular functions by removing ubiquitin modifications. We examined the effects of 88 human DUBs on linear ubiquitin chain assembly complex (LUBAC)-induced NF-κB activation, and identified OTUD1 as a potent suppressor. OTUD1 regulates the canonical NF-κB pathway by hydrolyzing K63-linked ubiquitin chains from NF-κB signaling factors, including LUBAC. OTUD1 negatively regulates the canonical NF-κB activation, apoptosis, and necroptosis, whereas OTUD1 upregulates the interferon (IFN) antiviral pathway. Mass spectrometric analysis showed that OTUD1 binds KEAP1, and the N-terminal intrinsically disordered region of OTUD1, which contains an ETGE motif, is indispensable for the KEAP1-binding. Indeed, OTUD1 is involved in the KEAP1-mediated antioxidant response and reactive oxygen species (ROS)-induced cell death, oxeiptosis. In Otud1−/−-mice, inflammation, oxidative damage, and cell death were enhanced in inflammatory bowel disease, acute hepatitis, and sepsis models. Thus, OTUD1 is a crucial regulator for the inflammatory, innate immune, and oxidative stress responses and ROS-associated cell death pathways.
Development of high-energy non-aqueous lithium-sulfur batteries via redox-active interlayer strategy
Authors: Lee Byong-June , Zhao Chen , Yu Jeong-Hoon , Kang Tong-Hyun , Park Hyean-Yeol , Kang Joonhee , Jung Yongju , Liu Xiang , Li Tianyi , Xu Wenqian , Zuo Xiao-Bing , Xu Gui-Liang , Amine Khalil , Yu Jong-Sung
Published: August 2022

Lithium-sulfur batteries have theoretical specific energy higher than state-of-the-art lithium-ion batteries. However, from a practical perspective, these batteries exhibit poor cycle life and low energy content owing to the polysulfides shuttling during cycling. To tackle these issues, researchers proposed the use of redox-inactive protective layers between the sulfur-containing cathode and lithium metal anode. However, these interlayers provide additional weight to the cell, thus, decreasing the practical specific energy. Here, we report the development and testing of redox-active interlayers consisting of sulfur-impregnated polar ordered mesoporous silica. Differently from redox-inactive interlayers, these redox-active interlayers enable the electrochemical reactivation of the soluble polysulfides, protect the lithium metal electrode from detrimental reactions via silica-polysulfide polar-polar interactions and increase the cell capacity. Indeed, when tested in a non-aqueous Li-S coin cell configuration, the use of the interlayer enables an initial discharge capacity of about 8.5 mAh cm−2 (for a total sulfur mass loading of 10 mg cm−2) and a discharge capacity retention of about 64 % after 700 cycles at 335 mA g−1 and 25 °C.
Acetate reprograms gut microbiota during alcohol consumption
Authors: Martino Cameron , Zaramela Livia S. , Gao Bei , Embree Mallory , Tarasova Janna , Parker Seth J. , Wang Yanhan , Chu Huikuan , Chen Peng , Lee Kuei-Chuan , Galzerani Daniela Domingos , Gengatharan Jivani M. , Lekbua Asama , Neal Maxwell , Knight Rob , Tsukamoto Hidekazu , Metallo Christian M. , Schnabl Bernd , Zengler Karsten
Published: August 2022

Liver damage due to chronic alcohol use is among the most prevalent liver diseases. Alcohol consumption frequency is a strong factor of microbiota variance. Here we use isotope labeled [1-13C] ethanol, metagenomics, and metatranscriptomics in ethanol-feeding and intragastric mouse models to investigate the metabolic impacts of alcohol consumption on the gut microbiota. First, we show that although stable isotope labeled [1-13C] ethanol contributes to fatty acid pools in the liver, plasma, and cecum contents of mice, there is no evidence of ethanol metabolism by gut microbiota ex vivo under anaerobic conditions. Next, we observe through metatranscriptomics that the gut microbiota responds to ethanol-feeding by activating acetate dissimilation, not by metabolizing ethanol directly. We demonstrate that blood acetate concentrations are elevated during ethanol consumption. Finally, by increasing systemic acetate levels with glyceryl triacetate supplementation, we do not observe any impact on liver disease, but do induce similar gut microbiota alterations as chronic ethanol-feeding in mice. Our results show that ethanol is not directly metabolized by the gut microbiota, and changes in the gut microbiota linked to ethanol are a side effect of elevated acetate levels. De-trending for these acetate effects may be critical for understanding gut microbiota changes that cause alcohol-related liver disease.
Programmable RNA targeting by bacterial Argonaute nucleases with unconventional guide binding and cleavage specificity
Authors: Lisitskaya Lidiya , Shin Yeonoh , Agapov Aleksei , Olina Anna , Kropocheva Ekaterina , Ryazansky Sergei , Aravin Alexei A. , Esyunina Daria , Murakami Katsuhiko S. , Kulbachinskiy Andrey
Published: August 2022

Argonaute proteins are programmable nucleases that have defense and regulatory functions in both eukaryotes and prokaryotes. All known prokaryotic Argonautes (pAgos) characterized so far act on DNA targets. Here, we describe a new class of pAgos that uniquely use DNA guides to process RNA targets. The biochemical and structural analysis of Pseudooceanicola lipolyticus pAgo (PliAgo) reveals an unusual organization of the guide binding pocket that does not rely on divalent cations and the canonical set of contacts for 5’-end interactions. Unconventional interactions of PliAgo with the 5’-phosphate of guide DNA define its new position within pAgo and shift the site of target RNA cleavage in comparison with known Argonautes. The specificity for RNA over DNA is defined by ribonucleotide residues at the cleavage site. The analysed pAgos sense mismatches and modifications in the RNA target. The results broaden our understanding of prokaryotic defense systems and extend the spectrum of programmable nucleases with potential use in RNA technology.
G protein coupling and activation of the metabotropic GABAB heterodimer
Authors: Yang Moon Young , Kim Soo-Kyung , Goddard William A.
Published: August 2022

Metabotropic γ-aminobutyric acid receptor (GABABR), a class C G protein-coupled receptor (GPCR) heterodimer, plays a crucial role in the central nervous system. Cryo-electron microscopy studies revealed a drastic conformational change upon activation and a unique G protein (GP) binding mode. However, little is known about the mechanism for GP coupling and activation for class C GPCRs. Here, we use molecular metadynamics computations to predict the mechanism by which the inactive GP induces conformational changes in the GABABR transmembrane domain (TMD) to form an intermediate pre-activated state. We find that the inactive GP first interacts with TM3, which further leads to the TMD rearrangement and deeper insertion of the α5 helix that causes the Gα subunit to open, releasing GDP, and forming the experimentally observed activated structure. This mechanism provides fresh insights into the mechanistic details of class C GPCRs activation expected to be useful for designing selective agonists and antagonists.
Photonic crystal enhanced fluorescence emission and blinking suppression for single quantum dot digital resolution biosensing
Authors: Xiong Yanyu , Huang Qinglan , Canady Taylor D. , Barya Priyash , Liu Shengyan , Arogundade Opeyemi H. , Race Caitlin M. , Che Congnyu , Wang Xiaojing , Zhou Lifeng , Wang Xing , Kohli Manish , Smith Andrew M. , Cunningham Brian T.
Published: August 2022

While nanoscale quantum emitters are effective tags for measuring biomolecular interactions, their utilities for applications that demand single-unit observations are limited by the requirements for large numerical aperture (NA) objectives, fluorescence intermittency, and poor photon collection efficiency resulted from omnidirectional emission. Here, we report a nearly 3000-fold signal enhancement achieved through multiplicative effects of enhanced excitation, highly directional extraction, quantum efficiency improvement, and blinking suppression through a photonic crystal (PC) surface. The approach achieves single quantum dot (QD) sensitivity with high signal-to-noise ratio, even when using a low-NA lens and an inexpensive optical setup. The blinking suppression capability of the PC improves the QDs on-time from 15% to 85% ameliorating signal intermittency. We developed an assay for cancer-associated miRNA biomarkers with single-molecule resolution, single-base mutation selectivity, and 10-attomolar detection limit. Additionally, we observed differential surface motion trajectories of QDs when their surface attachment stringency is altered by changing a single base in a cancer-specific miRNA sequence.
A 33-residue peptide tag increases solubility and stability of Escherichia coli produced single-chain antibody fragments
Authors: Wang Yang , Yuan Wenjie , Guo Siqi , Li Qiqi , Chen Xiaomei , Li Cheng , Liu Qianying , Sun Lei , Chen Zhenguo , Yuan Zhenghong , Luo Cheng , Chen Shijie , Tong Shuping , Nassal Michael , Wen Yu-Mei , Wang Yong-Xiang
Published: August 2022

Single-chain variable fragments (scFvs), composed of variable domains of heavy and light chains of an antibody joined by a linker, share antigen binding capacity with their parental antibody. Due to intrinsically low solubility and stability, only two Escherichia coli-produced scFvs have been approved for therapy. Here we report that a 33-residue peptide, termed P17 tag, increases the solubility of multiple scFvs produced in Escherichia coli SHuffle strain by up to 11.6 fold. Hydrophilic sequence, especially charged residues, but not the predicted α-helical secondary structure of P17 tag, contribute to the solubility enhancement. Notably, the P17 tag elevates the thermostability of scFv as efficiently as intra-domain disulfide bonds. Moreover, a P17-tagged scFv targeting hepatitis B virus surface proteins shows over two-fold higher antigen-binding affinity and virus-neutralizing activity than the untagged version. These data strongly suggest a type I intramolecular chaperone-like activity of the P17 tag. Hence, the P17 tag could benefit the research, production, and application of scFv.
Adaptation to chronic ER stress enforces pancreatic β-cell plasticity
Authors: Chen Chien-Wen , Guan Bo-Jhih , Alzahrani Mohammed R. , Gao Zhaofeng , Gao Long , Bracey Syrena , Wu Jing , Mbow Cheikh A. , Jobava Raul , Haataja Leena , Zalavadia Ajay H. , Schaffer Ashleigh E. , Lee Hugo , LaFramboise Thomas , Bederman Ilya , Arvan Peter , Mathews Clayton E. , Gerling Ivan C. , Kaestner Klaus H. , Tirosh Boaz , Engin Feyza , Hatzoglou Maria
Published: August 2022

Pancreatic β-cells are prone to endoplasmic reticulum (ER) stress due to their role in insulin secretion. They require sustainable and efficient adaptive stress responses to cope with this stress. Whether episodes of chronic stress directly compromise β-cell identity is unknown. We show here under reversible, chronic stress conditions β-cells undergo transcriptional and translational reprogramming associated with impaired expression of regulators of β-cell function and identity. Upon recovery from stress, β-cells regain their identity and function, indicating a high degree of adaptive plasticity. Remarkably, while β-cells show resilience to episodic ER stress, when episodes exceed a threshold, β-cell identity is gradually lost. Single cell RNA-sequencing analysis of islets from type 1 diabetes patients indicates severe deregulation of the chronic stress-adaptation program and reveals novel biomarkers of diabetes progression. Our results suggest β-cell adaptive exhaustion contributes to diabetes pathogenesis.
Acute health-related quality of life outcomes and systemic inflammatory markers following contemporary breast cancer surgery
Authors: Radin Arielle S. , Bower Julienne E. , Irwin Michael R. , Asher Arash , Hurvitz Sara A. , Cole Steve W. , Crespi Catherine M. , Ganz Patricia A.
Published: August 2022

Contemporary breast cancer surgical procedures vary greatly by the amount of tissue removed, anesthesia time, and reconstruction. Despite historical literature comparing the health-related quality of life (HRQOL) after lumpectomy and mastectomy, HRQOL data are limited regarding contemporary surgical procedures. Further, biological processes (e.g., inflammation) associated with HRQOL outcomes have not been described. We conducted two studies to examine differences in post-operative physical and mental functioning, pain, fatigue, and systemic inflammatory markers including interleukin (IL)-6, tumor necrosis factor (TNF)-α, and C-reactive protein (CRP) in women with early-stage breast cancer. Study 1 assessed women before and after surgery (n = 27) and Study 2 used a large cross-sectional sample (n = 240) to confirm findings from Study 1 and included a no-surgery comparison group. In Study 1, women who received mastectomy had lower physical functioning than lumpectomy (ps < 0.05), and those who received bilateral mastectomy had worse pain (p < 0.01) and fatigue (p = 0.029) than lumpectomy. Results were replicated in Study 2: mastectomy groups exhibited poorer physical functioning (ps < 0.01) and greater pain (ps < 0.001) than lumpectomy, and bilateral mastectomy was associated with worse fatigue (p < 0.05). Women who received bilateral mastectomy had higher levels of CRP than lumpectomy (p < 0.01) and higher TNF-α than the no-surgery group (p < 0.05). All surgery groups exhibited higher IL-6 than no-surgery (ps < 0.05). More extensive surgery is associated with poorer postoperative HRQOL. As compared to lumpectomy and no-surgery, mastectomy is associated with higher concentrations of systemic inflammatory markers.
Mass spectrometry of short peptides reveals common features of metazoan peptidergic neurons
Authors: Hayakawa Eisuke , Guzman Christine , Horiguchi Osamu , Kawano Chihiro , Shiraishi Akira , Mohri Kurato , Lin Mei-Fang , Nakamura Ryotaro , Nakamura Ryo , Kawai Erina , Komoto Shinya , Jokura Kei , Shiba Kogiku , Shigenobu Shuji , Satake Honoo , Inaba Kazuo , Watanabe Hiroshi
Published: August 2022

The evolutionary origins of neurons remain unknown. Although recent genome data of extant early-branching animals have shown that neural genes existed in the common ancestor of animals, the physiological and genetic properties of neurons in the early evolutionary phase are still unclear. Here, we performed a mass spectrometry-based comprehensive survey of short peptides from early-branching lineages Cnidaria, Porifera and Ctenophora. We identified a number of mature ctenophore neuropeptides that are expressed in neurons associated with sensory, muscular and digestive systems. The ctenophore peptides are stored in vesicles in cell bodies and neurites, suggesting volume transmission similar to that of cnidarian and bilaterian peptidergic systems. A comparison of genetic characteristics revealed that the peptide-expressing cells of Cnidaria and Ctenophora express the vast majority of genes that have pivotal roles in maturation, secretion and degradation of neuropeptides in Bilateria. Functional analysis of neuropeptides and prediction of receptors with machine learning demonstrated peptide regulation of a wide range of target effector cells, including cells of muscular systems. The striking parallels between the peptidergic neuronal properties of Cnidaria and Bilateria and those of Ctenophora, the most basal neuron-bearing animals, suggest a common evolutionary origin of metazoan peptidergic nervous systems.