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This study assesses the reliability and limitations of the Geostationary Lightning Mapper (GLM) in detecting continuing currents by comparing observations from ground‐based high‐speed cameras with GLM‐16 data. Our findings show that the GLM's one‐group detection efficiency (DE_1) is 53%, while the more stringent five‐consecutive‐group detection efficiency (DE_5) is 10%. Optical signals detected by the GLM predominantly occur during the early stages of continuing currents. Additionally, there is a notable disparity in detection efficiencies between positive and negative continuing currents, with positive continuing currents being detected more frequently. The application of the logistic regression model developed by Fairman and Bitzer (2022) further illustrates the limitations in continuing current identification. The study underscores the challenges of relying solely on satellite data to monitor and analyze continuing currents, emphasizing the need for advancements in detection technologies and methodologies to reliably detect continuing current at a large spatial scale. Plain Language Summary: This study investigates continuing current in cloud‐to‐ground lightning—a prolonged electrical discharge known for causing significant damage, such as igniting large‐scale wildfires. For the first time, we used recordings from ground‐based high‐speed cameras to assess how effectively the Geostationary Lightning Mapper (GLM), an optical instrument on the GOES satellite, detects these currents. Our findings reveal that the GLM often captures only the early stages of continuing currents and struggles to detect them consistently, particularly those in weaker, negative types of lightning. These results underscore the limitations of current satellite‐based optical instruments in fully monitoring continuing currents, emphasizing the need for improved methods to better detect and understand these electrical discharges and mitigate their impacts. Key Points: The Geostationary Lightning Mapper is limited in detecting continuing current, with a one‐group DE of 53% and a five‐group DE of just 10%Optical signals captured by the Geostationary Lightning Mapper are predominantly during the early stage of continuing currentsA significant disparity is observed in GLM detection efficiencies between positive and negative continuing currents [ABSTRACT FROM AUTHOR]

Organic thermally activated delayed fluorescent (TADF) scintillators hold promising potential for applications in medical radiography and security detection, but the poor X‐ray absorption ability and inferior radioluminescence (RL) hampered their progression. Herein, the study has pioneered the development of high‐performance TADF Ag(I)‐based scintillators from M2X2(dppb)2 (M = Ag, Cu; X = Cl, Br, I) complexes with 1,2‐Bis(diphenylphosphino)benzene (dppb) ligand. In comparison with Cu(I) complexes, the Ag(I) series generally exhibited superior scintillation performance. Notably, Ag2Cl2(dppb)2 (Ag1) stands out with exceptionally high RL intensity (≈125% higher than that of CsI:Tl) and a low detection limit of 59.8 nGy s−1. The outstanding scintillation performance of Ag1 is primarily attributed to the synergistic effect of the high exciton utilization efficiency origin from a small singlet‐triplet energy gap, enhanced X‐ray absorption capacity by heavy atoms, and the high photoluminescence quantum yield (76.47% in ambient atmosphere). By fabricating a flexible film constructed with Ag1 submicron crystalline powders, a high spatial resolution of 25.0 lp mm−1 for X‐ray imaging is obtained. It offers new opportunities for utilizing TADF metal–organic complexes for highly efficient X‐ray scintillation and imaging. [ABSTRACT FROM AUTHOR]

The bio‐based hydrophilic monoglycerol succinate was synthesized and reacted with bio‐based raw materials including polyols, pentamethylene diisocyanate, 1,4‐butanediol, to prepare the waterborne polyurethane acrylate (Bio‐WPUA) emulsions with high bio‐based content. The effect of bio‐based polyol categories including poly(trimethylene ether glycol), poly(tetrahydrofuran), and castor oil on the properties of Bio‐WPUA and its films were studied. The structure, thermal stability, crystallinity, contact angle, and mechanical properties of Bio‐WPUA film were characterized with fourier infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, X‐ray diffraction, contact angle analyzer, and mechanical tensile testing. It was found that Bio‐WPUA film containing poly(trimethylene ether glycol) as the soft‐segmented display good tensile stress, thermal stability, and water resistance with 1.38% of the water absorption rate, while Bio‐WPUA containing castor oil polyol as the soft‐segmented had good tensile strain and low‐temperature film‐forming properties with excellent film properties. The bio‐carbon content of Bio‐WPUA was high up to 40% according to ASTM D6866‐22, and possesses good physical mechanical and chemical resistance performance. The results provide theoretical guidance for the synthesis of polyurethane emulsions with bio‐based materials instead of petroleum‐based materials. [ABSTRACT FROM AUTHOR]

Background: Exosomes and other secretory membrane vesicles, collectively referred to as extracellular vesicles (EVs), have garnered increasing attention in research due to their biological characteristics. Notably, studies have shown promising results regarding the role of stem cell‐derived extracellular vesicles (SC‐EVs) in skin and plastic surgery applications. This study aims to elucidate current trends in SC‐EVs within the context of skin and plastic surgery and offer insights for future research directions in advancing this critical field. Methods: A comprehensive search was conducted for relevant studies on SC‐EVs in skin and plastic surgery spanning from 2003 to 2023, utilizing the Web of Science database. Subsequently, data analysis was performed using VOSviewer and CiteSpace. Results: A total of 1089 studies were identified, with a noticeable annual increase in publications on SC‐EVs' application in skin and plastic surgery. China emerged as the leading contributor to this field, with Shanghai Jiao Tong University being a notable institution. Stem Cell Research & Therapy and the International Journal of Molecular Sciences were the top journals publishing relevant articles. Author Fu Xiaobing from the Chinese People's Liberation Army General Hospital had the highest publication count in this area. Keyword co‐occurrence analysis revealed six distinct clusters, with "exosomes" being the most prevalent keyword in recent years. Wound healing and skin rejuvenation emerged as primary research focuses and hotspots in this field. Conclusion: This comprehensive review offers insights into global trends surrounding SC‐EVs in skin and plastic surgery. Analysis of journals, institutions, references, and keywords provides valuable guidance for researchers in determining future research directions. [ABSTRACT FROM AUTHOR]

Narrow bipolar events (NBEs) are impulsive and powerful intracloud discharges. Recent observations indicate that some NBEs exhibit a slanted orientation rather than strictly vertical. This paper investigates the effect of the slanted NBEs using a newly developed rebounding‐wave model. The modeling results are validated against the full‐wave Finite‐ Difference Time‐Domain method and compared with measurements for both vertical and slanted NBE cases. It is found that the inclination of the NBEs affects both the waveforms and amplitudes of the electrostatic, induction and radiation components of the electric fields at close distances (≤10 km). However, it primarily influences the amplitudes of the fields for distances beyond 50 km, where the radiation component dominates, resulting in changes of ≥30% when the slant angle exceeds 30°. The slanted rebounding‐wave model improves the agreement with respect to a purely vertical channel and can be extended to any discharge geometry at arbitrary observation distances. Plain Language Summary: Narrow Bipolar Events (NBEs) are unique intracloud discharges that occur either individually or as the initiation event for lightning flashes inside thunderstorms. Knowing the physical mechanisms of NBEs will help us to better understand how lightning initiates inside thunderstorms. Recent studies indicated that NBEs could exhibit a slanted orientation rather than being strictly vertical. However, the inclination of NBEs has not been considered in previous transmission line models, leading to uncertainty when evaluating their characteristics based on electromagnetic fields. Here, in the light of recent observations, we analyze the propagation effect of the slanted NBEs by using a newly developed slanted rebounding‐wave model, and we compare the modeling results with observations. This study contributes to a better understanding of the physical mechanism of NBEs and provides a reference for accurately characterizing NBEs based on their electromagnetic fields. Key Points: The propagation effect of slanted Narrow bipolar events (NBEs) at different distance is investigated and compared with the observationsThe inclination of the NBEs could significantly affect the electromagnetic fields in the close distanceThe proposed equations will improve the quality of inferred features of slanted NBEs and can be extended to any discharge shape [ABSTRACT FROM AUTHOR]

Background and Objective: While earlier studies have focused on the relationship between stress and obesity, there was a gap in understanding the potential impact of positive psychological factors, such as resilience, on obesity. By investigating the role of psychological resilience with obesity, this study aimed to address this gap and tackle obesity through a positive psychological framework. Methods: Participants consisted of 2445 community residents from Shenzhen, China, with a mean age of 41.09 ± 13.72 years, comprising 846 males and 1599 females. Psychological resilience was measured using the Brief Resilience Scale; gender, age, marital status, education level, smoking status, alcohol consumption, frequency of physical exercise, and perceived stress were considered potential confounding factors. The relationship between psychological resilience and body mass index (BMI) was examined through multiple linear regression and logistic regression analyses. Results: The participants had an average psychological resilience score of 3.46 (standard deviation [SD] = 0.62) and an average BMI of 22.59 (SD = 3.35), with 104 individuals (4.3%) identified with obesity. In the fully adjusted multiple linear regression model, a higher psychological resilience score was associated with a higher BMI (β = 0.507, 95% CI:0.283, 0.731). In the logistic regression model, higher psychological resilience scores were linked to increased obesity risk, with a more significant association observed among males (odds ratio [OR] = 2.169, 95% CI:1.155, 4.073), while psychological resilience acted as a protective factor against underweight among females (OR = 0.528, 95% CI:0.376, 0.816). Conclusion: The study demonstrated a significant link between higher psychological resilience and elevated BMI, emphasizing the complex relationship between psychological fortitude and weight management. Interventions targeting socioeconomic status, education, lifestyle habits, and physiological well‐being might offer a promising strategy for enhancing psychological resilience and promoting healthier weight. Emphasizing self‐efficacy and coping skills at the individual level could contribute to balanced weight and comprehensive health outcomes, addressing the global challenge of obesity. [ABSTRACT FROM AUTHOR]

The classical vorticity‐streamfunction formulation (VSF) can avoid the difficulty in the calculation of pressure gradient term of the Navier Stokes equation via eliminating pressure gradient term from the theoretical basis. Within this context we propose a general VSF, together with redefined vorticity and streamfunction, so as to realize numerically stable and reliable simulations of binary fluids with an arbitrary density contrast. By incorporating the interface‐tracking phase‐field model based on the conservative Allen‐Cahn equation [Phys. Rev. E 94, 023311 (2016)], the binary flow simulation framework is established. Numerical tests are conducted using the Lattice Boltzmann method (LBM), which is usually regarded as an easy‐to‐use tool for solving the Navier–Stokes equation but generally suffers from the drawback of not being capable of enforcing incompressibility. The LBM herein functions as a numerical tool for solving the vorticity transport equation, the streamfunction equation, and the conservative Allen‐Cahn equation. Three two‐dimensional benchmark cases, i.e., the Capillary wave, the Rayleigh–Taylor instability, and the droplet splashing on a thin liquid film, are discussed in detail to verify the present methodology. Results show good agreements with both analytical predictions and literature data, as well as good numerical stability in terms of high density ratio and high Reynolds number. Overall, the general VSF inherits the intrinsic superiority of the classical VSF in enforcing incompressibility, and offers a useful and reliable alternative for binary flow modeling. [ABSTRACT FROM AUTHOR]

Flexible, lightweight, and cost‐effective organic light‐emitting diodes (OLEDs) show great promise for use in displays and lighting applications. However, creating highly efficient and stable deep‐blue OLEDs remains a challenge due to a lack of efficient functional materials, specifically hole transport materials (HTM). In this report, two new spiro‐HTMs are introduced with fluorene (FBP‐SFX) or dibenzofuran (DBF‐SFX) peripheral substituents. This study finds that the DBF‐SFX variant produces highly efficient deep‐blue OLEDs with a narrow emission (full‐width at half‐maximum FWHM of 25 nm) and the highest external quantum efficiency (EQE) of 33.2% among the FBP‐SFX (12.2%) and NPB (11.9%) variants. The superior performance of DBF‐SFX is attributed to its deeper highest occupied molecular orbital level (HOMO) and small trap density, which results in reduced band‐edge offset, lower turn‐on voltages, and balanced charge carrier densities. Importantly, the blue fluorescence OLED with DBF‐SFX displays exceptional device stability with LT95 over 420 h with an initial luminance of 1000 cd m−2. This is due to the stronger bond dissociation energy (BDE) and suppressed Exciton–Polaron Annihilation (EPA) using the dibenzofuran substituent. This work demonstrates a new HTM design approach using a spiro‐core architecture and dibenzofuran substituents to create efficient and long‐lasting deep‐blue OLEDs. [ABSTRACT FROM AUTHOR]

Blue corona discharges are often observed at the top of thunderclouds. They are bursts of streamers, but the cloud conditions that enable them are not well known. Here we present observations by the Atmosphere‐Space Interactions Monitor (ASIM) of 92 discharges during its ∼1 min pass over tropical cyclone Fani in the Bay of Bengal from 20:10:55 to 20:12:05 UTC on 30 April 2019. The discharges were observed in convective cells forming in the rainbands of the cyclone where Convective Available Potential Energy reached ∼6,000 J kg−1. The Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation satellite passed over one of the cells ∼12 min after ASIM from 20:23:58 to 20:24:14 UTC. It measured the cloud microphysics related to the discharges and indicated they occurred in a convection region with the cloud top overshooting for over 20 min. The updraft lifted ice particles to lower stratospheric altitudes and formed the gullwing‐shaped cirrus. The discharges are found at an average altitude of ∼16 km where the cloud environment contained ∼2 × 107 m−3 ice particles with ∼50 µm radius, resulting in a photon mean free path of ∼3 m. Around 20% of the blue corona discharges coincide with Narrow Bipolar Events indentified from the Earth Networks Total Lightning Network. Our observations suggest that the overshooting cloud top formed by deep convection and a surge in lightning activity facilitated conditions for the blue corona discharges. This work provides the first‐ever estimate of important microphysical parameters related to blue corona discharges based on data measurements, establishing a reference for future empirical and theoretical studies. Plain Language Summary: Blue corona discharges are bursts of streamer discharges often observed at the top of thunderclouds, but the conditions in the clouds that generate them are not well understood. In this study, we discuss observations of blue corona discharges in convective cells detected by the Atmosphere‐Space Interactions Monitor on the International Space Station as it passed over cyclone Fani in the Bay of Bengal. For the first time, we have observations of the cloud particle characteristics at the cloud tops taken shortly afterward by the Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation satellite, which are related to the blue corona discharges. The observations indicate that the blue corona discharges may be Narrow Bipolar Events associated with strong convection in cloud cells reaching into the stratosphere. The cloud microphysical parameters related to blue corona discharges are important for future empirical studies and for theoretical models and simulations. Key Points: First combined observations of optical activity, cloud microphysics and lightning related to blue corona discharges in a tropical cycloneThe source depth of the blue corona discharges inside the cloud estimated from optical and radio observations agree wellBlue corona discharges are related to a strong updraft, high‐density large ice particles and an increase in the total lightning rate [ABSTRACT FROM AUTHOR]

This paper is concerned with a multi‐coalition noncooperative game with coupling equality constraints. Each coalition is a player consisted of multiple agents in noncooperative games and desire to minimize its own objective function based on local information. Each agent as actual decision maker in the same coalition is to optimize the objective function of the coalition cooperately. To seek a generalized Nash equilibrium (GNE) of the multi‐coalition game, a distributed continuous‐time algorithm is developed. Moreover, to further reduce the communication among agents and coalitions, an event‐triggered mechanism (ETM) is introduced for the multi‐coalition game. By using ETM, a novel distributed GNE seeking algorithm is proposed, where agents and coalitions are allowed to exchange estimation information with neighbors only when the triggering condition is satisfied. Remarkably, the proposed event‐triggered scheme introduces internal variables to regulate its threshold dynamically, which excludes Zeno behavior. By Lyapunov analysis, it is proved that the coalitions' decision variables converge to a GNE in both algorithms. Finally, the effectiveness of the proposed methods is validated by numerical simulations. [ABSTRACT FROM AUTHOR]

Apolipoprotein E (ApoE)'s ϵ4 alle is the most important genetic risk factor for late onset Alzheimer's Disease (AD). Cell‐surface heparan sulfate (HS) is a cofactor for ApoE/LRP1 interaction and the prion‐like spread of tau pathology between cells. 3‐O‐sulfo (3‐O‐S) modification of HS has been linked to AD through its interaction with tau, and enhanced levels of 3‐O‐sulfated HS and 3‐O‐sulfotransferases in the AD brain. In this study, we characterized ApoE/HS interactions in wildtype ApoE3, AD‐linked ApoE4, and AD‐protective ApoE2 and ApoE3‐Christchurch. Glycan microarray and SPR assays revealed that all ApoE isoforms recognized 3‐O‐S. NMR titration localized ApoE/3‐O‐S binding to the vicinity of the canonical HS binding motif. In cells, the knockout of HS3ST1‐a major 3‐O sulfotransferase‐reduced cell surface binding and uptake of ApoE. 3‐O‐S is thus recognized by both tau and ApoE, suggesting that the interplay between 3‐O‐sulfated HS, tau and ApoE isoforms may modulate AD risk. [ABSTRACT FROM AUTHOR]

Aim: The aim of the study was to explore whether hexokinase 1 (HK1) is involved in the inhibition of inflammation mediated by nucleotide‐binding oligomerization domain‐like receptor protein 3 (NLRP3) signalling pathway in the development of apical periodontitis (AP). Methodology: Human AP tissues and normal control tissues were collected in the clinic. First, the levels of glucose, pyruvate, lactate and hexokinase activity were examined in human AP tissues. ECAR and OCR were further measured to detect the level of glycolysis in vitro model of inflammation, which established with lipopolysaccharide (LPS)‐stimulated RAW264.7 cell line. Secondly, the expression of HK1, NLRP3, caspase‐1 and interleukin (IL)‐1β were measured by Western blot, immunohistochemistry or RT–qPCR. Finally, lentiviral short hairpin RNA (shRNA) silencing technique or the inhibitor 2‐deoxy‐d‐glucose (2‐DG) were used to further detect the relationship between HK1‐mediated glycolysis and NLRP3‐mediated inflammation in the development of AP in vitro. Results: Initially, the level of glycolysis was significantly increased in human AP tissues. Subsequently, the expression of HK1, NLRP3, caspase‐1 and IL‐1β were upregulated significantly in human AP tissues. Furthermore, in the model of AP in vitro, a high level of glycolysis and the high expression of HK1, NLRP3, caspase‐1 and IL‐1β was observed. Finally, the expression of NLRP3, caspase‐1 and IL‐1β mediated by LPS stimulation was significantly reduced via HK1 knockdown or 2‐DG treatment in vitro. Conclusions: Our data support that HK1‐mediated glycolysis plays a crucial role in the development of AP via upregulating the NLRP3 signalling pathway. Moreover, targeting HK1 may contribute to prevent the progression of AP, which has a potential clinical translation. [ABSTRACT FROM AUTHOR]

The transformation from metal nanocluster catalysts to metal single‐atom catalysts is an important procedure in the rational design of atomically dispersed metal catalysts (ADCs). However, the conversion methods often involve high annealing temperature as well as reducing atmosphere. Herein, we reported a continuous and convenient approach to transfer Pd nanocluster into Pd single‐atom in a ligand assisted annealing procedure, by which means we reduced its activating temperature low to 400 °C. Using ex‐situ microscopy and spectroscopy, we comprehensively monitored the structural evolution of Pd species though the whole atomization process. Theoretical calculation revealed that the structural instability caused by remaining Cl ligands was the main reason for this low‐temperature transformation. The present atomization strategy and mechanistic knowledge for the conversion from cluster to atomic dispersion provides guidelines for the rational design of ADCs. [ABSTRACT FROM AUTHOR]

This article studied the mechanism of the influence of light‐curing 3D forming parameters of acrylic resin on its tribological and mechanical properties. A three‐factor hybrid orthogonal table was designed, that is, the three key process parameters of printing monolayer thickness (P), heat treatment (H), and ultraviolet curing treatment (U). The priority of three process parameters affecting tribological performance was studied based on Gray Correlation Theory. The results showed that the order of priority was P, U, and H. The tribological and mechanical properties of acrylic resin decreased with the increase of printing monolayer thickness, while the printing efficiency increased with the increase of the printing monolayer thickness. Based on Gray Correlation Theory, the "Wear Resistance Efficiency" (WRE) parameter was defined to comprehensively evaluate the wear resistance and printing efficiency of the samples. When the thickness of the printing monolayer was 30 μm, the comprehensive properties of the material reached the optimal value. The U increased the cross‐linking degree of the acrylic interlayer molecules, and the H reduced the residual stress generated during the printing of the samples. The research results provided data support for the application of 3D printing acrylic resin and its nanocomposites in the field of tribology. [ABSTRACT FROM AUTHOR]

Hot exciton materials have the potential to improve the quantum efficiency of organic light‐emitting diodes (OLEDs) by promoting high reversed intersystem crossing (hRISC) between a high‐lying triplet (Tn, n ≥ 2) and a radiative singlet (Sm). In recent years, donor–acceptor–donor (D–A–D) molecular systems have shown great promise in its ability to enhance the hRISC process under certain conditions. However, strategies to find appropriate D–A–D combinations beyond trial‐and‐error are still elusive. This work exposes the limited applicability of the current fragment‐based design rules and proposes high‐throughput screening as the optimal route to find candidates that fulfill the energy criteria for hRISC. The strategy consists of first establishing the thresholds for large triplet–triplet splitting and small singlet–triplet gap, then filtering combinations through rate comparison of competitive crossing pathways, and finally confirming hRISC with spin‐orbital coupling evaluation. Based on a dataset of 234 compounds, this protocol identifies 31 candidates with potential for hRISC, 4 of which are reported in the literature. Remarkably, while most of the promising systems show prominent hybridized local and charge transfer character, several candidates do not fulfill this condition, indicating that different routes are possible to design efficient OLED materials. [ABSTRACT FROM AUTHOR]

Ultrafine nanoclusters with precise structure as catalysts are of particular interest due to high sites density, high metal atomic efficiency and potentially favorable metal‐support interactions. In this work, we used a simple wet impregnation method to fix three Cun(n=3, 6, 11) nanoclusters (NCs) on activated carbon (AC). The structural characteristics of the three obtained Cun(n=3, 6, 11)/AC catalysts were analyzed by FT‐IR, XRD, TEM and XPS. Cun(n=3, 6, 11)/AC catalysts are used for exploring catalytic performance of alkyne‐haloalkane‐amine (AHA) coupling reaction. The results show that Cun(n=3, 6, 11)/AC catalysts exhibited better catalytic activity for AHA coupling reaction than Cu salt and other non‐noble metal catalysts, with TON up to 715.4. This work provides a new way to understand the relationship between structure and catalytic performance of ultra‐small copper NCs. [ABSTRACT FROM AUTHOR]

Sea surface temperature anomalies (SSTAs) induced by oceanic mesoscale eddies trigger mesoscale air‐sea interactions and modulate large‐scale climate systems. Yet, how eddies drive SSTAs has not been firmly established; particularly, the relative importance of lateral stirring and vertical pumping remains a debated issue. This study investigates characteristics and generation mechanisms of mesoscale eddy SSTAs in three eddy‐enriched domains of the North Pacific Ocean: the Kuroshio Extension (KET), the Subtropical Countercurrent (STCC), and the North Equatorial Countercurrent (NECC). Analysis of satellite observational data reveals quasi‐monopole eddy SSTAs in the KET and NECC and dipole‐like eddy SSTAs in the STCC. By investigating spatial and seasonal variations and performing sensitivity experiments using an idealized model, we demonstrate that lateral stirring plays a more important role than vertical pumping in causing mesoscale eddy SSTAs. The eastward transport by the strong background current UC (∼0.6 and ∼0.4 m s−1 in the KET and the NECC, respectively) and the westward eddy translation UT (∼−0.2 m s−1 in the NECC) can dramatically modify the structure of SSTA. The pure stirring effect of eddy rotation velocities generates strong dipole‐like SSTAs. Owing to the eastward UC and the westward UT, the western SSTA pole tends to approach the eddy center, while the eastern SSTA pole departs from the eddy and scatters along the eddy trajectory. These effects reduce the eddy SSTA amplitude and favor the emergence of quasi‐monopole structure. This work provides a useful benchmark for model simulations of mesoscale SST variability and air‐sea interaction. Plain Language Summary: Mesoscale sea surface temperature anomalies (SSTAs) of tens to hundreds of kilometers induced by oceanic eddies are one of the most striking features of satellite SST images. Yet, we still have no firm answer to the question as to how eddies drive SSTAs. Particularly, whether the eddy SSTAs are induced by lateral stirring or vertical pumping is unknown. Here, by analyzing satellite data, we identify both monopole‐like (a single warming/cooling core within the eddy) and dipole‐like (a pair of opposite‐sign anomaly patches) eddy SSTAs in the North Pacific, and they are both intimately associated with the lateral stirring of eddies. We further demonstrate that the existence of eastward background current and westward movement of eddies are favorable for the generation of such quasi‐monopole SSTAs. While the pure stirring effect of the eddy rotation produces dipole‐like SSTAs, the eastward UC and the westward UT gradually push the western SSTA pole toward the eddy center and finally give rise to quasi‐monopole SSTA structure. In addition to insights into the mechanisms, our work provides useful knowledge for the simulation of mesoscale SST variability and air‐sea interaction by climate models. Key Points: Eddy‐induced sea surface temperature anomalies (SSTAs) show a quasi‐monopole structure in the Kuroshio Extension and North Equatorial Countercurrent regionsLateral stirring acts as a major driver of eddy SSTA in the North PacificEastward mean current and westward eddy translation favor monopole SSTAs [ABSTRACT FROM AUTHOR]

Previous studies have shown that subsequent leaders in positive cloud‐to‐ground lightning (+CG) flashes rarely traverse pre‐existing channels to ground. In this paper, we present evidence that this actually can be common, at least for some thunderstorms. Observations of +CG flashes in a supercell storm in Argentina by Córdoba Argentina Marx Meter Array (CAMMA) are presented, in which 54 (64%) of 84 multiple‐stroke +CG flashes had subsequent leaders following a pre‐existing channel to ground. These subsequent positive leaders are found to behave similarly to their negative counterparts, including propagation speeds along pre‐existing channels with a median of 8 × 106 m/s, which is comparable to that of negative dart leaders. Two representative multiple‐stroke +CG flashes are presented and discussed in detail. The observations reported herein call for an update to the traditional explanation of the disparity between positive and negative lightning. Plain Language Summary: Despite the fact that positive lightning is more energetic and more likely to result in severe damage than negative lightning, it remains much less understood than its negative counterpart. We report on a totally unexpected behavior of positive lightning produced by a supercell thunderstorm in Argentina. Specifically, the observed positive lightning flashes were composed of multiple strokes retracing the same channel to ground, which differs from the expectation that positive lightning rarely delivers charge to the same place on the ground in a discrete manner. Our observations show that the behavior of subsequent leaders in positive lightning can be very similar to that of subsequent leaders in negative lightning. Our findings call for a change to our current understanding of positive lightning. Key Points: 54 of 84 multiple‐stroke +CG flashes produced by a supercell in Argentina had subsequent strokes following pre‐existing channels to groundSpeeds of descending positive leaders that traverse a channel created by a previous positive stroke are reported for the first timeSubsequent leaders in positive lightning initiated in the same way as counterparts in negative lightning [ABSTRACT FROM AUTHOR]

Hole mobility plays a critical role in organic semiconductors, which is synergistically controlled by many factors closely interrelated to the molecular configuration, for example, the degree of molecular planarization. But at present, analysis from quantitative ab initio models to assess this correlation is lacking. Here, a series of triphenylamine‐based materials are designed and investigated to build a system with different levels of planarization. The key parameters in the Marcus equation are calculated with quantum and molecular mechanics methods and the hole mobilities are evaluated. Compared with non‐planar and fully planar molecules, localized planar molecules exhibit low reorganization energy, high transfer integral, and moderate energy disorder. Considering the conjugation and rigidity effects, a localized planarization strategy is demonstrated to design functional triphenylamine‐based materials by keeping a balance of the three factors above and enhanced hole mobilities are predicted. This strategy will shed light on mobility optimization and the applications of triphenylamine‐based materials. [ABSTRACT FROM AUTHOR]

Near the southern tip of the African continent, the Agulhas Current retroflects eastward to feed the Agulhas Return Current, giving rise to the Agulhas Retroflection (AR). The AR is dynamically unstable and radiates eddies and rings that constitute a portion of the Agulhas leakage. In this study, by analyzing 26 years (1993–2018) of updated satellite altimetry data, the spatial and temporal characteristic of the surface AR point are revisited. By adopting a refined identification algorithm of the AR point, we show that the AR longitude (XAR) fluctuates widely between 7° and 27°E on timescales ranging from days to months, without a stable seasonal cycle. The XAR variability also shows evident temporal asymmetry with shorter residence time at western positions. The retreat of the AR from the western to eastern positions tends to be swift, with 46% of the events completed in one day. In comparison, the intrusion from the eastern to western positions is much slower, with 32% of the events taking more than one month. The energy transfer from the mean flow to mesoscale eddies is likely the primary regime underlying the AR variability. Further analysis suggests that the AR variability causes sea surface temperature anomalies of ∼0.5°C through anomalous advection and thereby gives rise to turbulent heat flux anomalies of ∼10 W m−2, exerting potential impacts on the local climate. Plain Language Summary: The Agulhas Retroflection (AR) is a key feature of the Agulhas Current system, and the choke point for the inter‐basin exchange between the Indian and Atlantic Oceans. The AR also serves as the origin of the Agulhas leakage that is constituted by northwestward moving eddies and rings radiated from the AR. Although there has been literature exploring the dynamics of the Agulhas Current and Agulhas leakage, our understanding of the AR variability is still incomplete. Using 26 years of updated satellite observation data of 1993–2018, we show that the mean longitude of the surface AR point is 17.5°E, and its fluctuation can be as wide as 7°−27°E. Owing to its strong variability and irregular behaviors, the AR does not possess a robust seasonal cycle. The AR behaviors are asymmetric: its residence time in the west tends to be much shorter than in the east. The interaction between the mean flow and mesoscale eddies is likely an essential regime controlling the AR variability. We also show that the AR variability can cause strong anomalies in regional sea surface temperature and air‐sea heat fluxes, which has potential influence on the local climate. Key Points: The mean longitude of the AR is 17.5°E with a standard deviation of 2.6°E and shows temporal asymmetry in westward and eastward phasesThe energy transfer from mean flow to eddies is likely the primary mechanism regulating the AR variabilityThe AR variability causes local SST anomalies of ∼0.5°C and surface heat flux anomalies of ∼10 W m−2 [ABSTRACT FROM AUTHOR]

A new automated method to retrieve charge layer polarity from flashes, named Chargepol, is presented in this paper. Using data from the NASA Lightning Mapping Array (LMA) deployed during the Remote sensing of Electrification, Lightning, And Mesoscale/microscale Processes with Adaptive Ground Observations (RELAMPAGO) field campaign in Cordoba, Argentina, from November 2018 to April 2019, this method estimates the polarity of vertical charge distributions and their altitudes and thicknesses (or vertical depth) using the very‐high frequency (VHF) source emissions detected by LMAs. When this method is applied to LMA data for extended periods of time, it is capable of inferring a storm's bulk electrical charge structure throughout its life cycle. This method reliably predicted the polarity of charge within which lightning flashes propagated and was validated in comparison to methods that require manual assignment of polarities via visual inspection of VHF lightning sources. Examples of normal and anomalous charge structures retrieved using Chargepol for storms in Central Argentina during RELAMPAGO are presented for the first time. Application of Chargepol to five months of LMA data in Central Argentina and several locations in the United States allowed for the characterization of the charge structure in these regions and for a reliable comparison using the same methodology. About 13.3% of Cordoba thunderstorms were defined by an anomalous charge structure, slightly higher than in Oklahoma (12.5%) and West Texas (11.1%), higher than Alabama (7.3%), and considerably lower than in Colorado (82.6%). Some of the Cordoba anomalous thunderstorms presented enhanced low‐level positive charge, a feature rarely if ever observed in Colorado thunderstorms. Key Points: A new automated method to estimate the polarity, altitude, and vertical depth of charge layers from flashes is presentedThunderstorm charge structures in Central Argentina are characterized from months of Lightning Mapping Array (LMA) data, with 13.3% anomalous charge structureCordoba anomalously charged thunderstorms have a distinct charge altitude distribution when compared to those in Colorado [ABSTRACT FROM AUTHOR]

An interesting downward positive cloud‐to‐ground lightning (DPCG) initiated by an upward negative cloud‐to‐ground lightning (UNCG) was recorded by the instruments installed at the Tall‐Object Lightning Observatory in Guangzhou. The characteristics of the discharges before and after the DPCG return stroke were investigated in detail using both optical and electric field change data. The UNCG was triggered from the tip of the Canton Tower (600 m high) by a distant +CG lightning. A sequence of intracloud (IC) discharges developed toward and connected to several pre‐existing channels of the UNCG. As a result, some positive charge was pumped from remote thundercloud regions to the region around the intersection of the pre‐existing and new channels. A branch of one IC channel developed from the intersection point toward the ground, transformed into a downward positive leader, terminated on the ground, and resulted in a positive return stroke. After that, the discharge processes in the cloud continued to neutralize the remaining positive charge. The UNCG served to facilitate the IC discharges that supplied positive charges for the DPCG. Most of the charge involved in the UNCG‐initiated DPCG originated from remote positively charged regions in the cloud. These observations constitute evidence for a new scenario of the initiation of +CG lightning. Key Points: A downward +CG initiated by an upward tall‐object ‐CG was recorded for the first timeThe characteristics of the discharges before and after the +CG were investigated using optical and electric field change dataThe observed sequence of events constitutes evidence for a new scenario of the initiation of downward +CG [ABSTRACT FROM AUTHOR]

High‐speed video and electric field change data were used to analyze the initiation and propagation of four predominantly vertical bidirectional leaders making connection to a predominantly horizontal channel previously formed aloft. The four bidirectional leaders sequentially developed along the same path and served to form a positive branch of the horizontal in‐cloud channel, which became a downward positive leader producing a 135‐kA positive cloud‐to‐ground (+CG) return stroke. The positive (lower) end of each bidirectional leader elongated abruptly at the time of connection of the negative (upper) end to the pre‐existing channel aloft. Thirty‐six negative streamer‐like filaments (resembling recently reported "needles") extended sideways over ∼110 to 740 m from the pre‐existing horizontal channel at speeds of ∼0.5 to 1.9 × 107 m/s, in response to the injection of negative charge associated with the +CG. Plain Language Summary: This paper presents high‐speed video records that show how a sequence of predominantly vertical bidirectional leaders can lead to formation of a positive branch of the previously formed predominantly horizontal channel aloft, with this branch eventually making contact with the ground and initiating a positive cloud‐to‐ground (+CG) return stroke. Additionally, the recently discovered "needles" have been optically imaged and characterized. Observations were performed at the Tall‐Object Lightning Observatory in Guangzhou (TOLOG), China. This study helps to improve our understanding of one of the initiation mechanisms of +CG flashes that involves downward branching of in‐cloud lightning channels. Key Points: Bidirectional leaders developed below a previously formed horizontal channel and served to form a new positive branch that attached to the groundConnection of the negative (upper) end of each bidirectional leader to the horizontal channel resulted in abrupt elongation of the positive (lower) endFlickering streamer‐like filaments (needles) extended sideways from the horizontal channel in response to the injection of negative charge associated with the positive cloud‐to‐ground flash [ABSTRACT FROM AUTHOR]

Incorporation of microbiome data has recently become important for prevention, diagnosis, and treatment of colorectal cancer, and several species of bacteria were shown to be associated with carcinogenesis. However, the role of commensal fungi in colon cancer remains poorly understood. Here, we report that mice lacking the c‐type lectin Dectin‐3 (Dectin‐3−/−) show increased tumorigenesis and Candida albicans burden upon chemical induction. Elevated C. albicans load triggered glycolysis in macrophages and interleukin‐7 (IL‐7) secretion. IL‐7 induced IL‐22 production in RORγt+ (group 3) innate lymphoid cells (ILC3s) via aryl hydrocarbon receptor and STAT3. Consistently, IL‐22 frequency in tumor tissues of colon cancer patients positively correlated with fungal burden, indicating the relevance of this regulatory axis in human disease. These results establish a C. albicans‐driven crosstalk between macrophages and innate lymphoid cells in the intestine and expand our understanding on how commensal mycobiota regulate host immunity and promote tumorigenesis. SYNOPSIS: Contribution of gut‐resident mycobiota and their host recognition receptors to colitis‐associated colon cancer (CAC) remains unclear. Here, deficiency in the surface lectin Dectin‐3 is shown to induce fungal dysbiosis and tumorigenesis in mice, skewing immune cell metabolism and cytokine signaling. Depletion of c‐type lectin Dectin‐3 increases Candida albicans burden and CAC in vivo.Elevated C. albicans load triggers glycolysis and inflammatory IL‐7 secretion from macrophages.Macrophage‐derived IL‐7 induces IL‐22 secretion by group‐3 innate lymphoid cells, as well as cancer development.Antifungal treatment ameliorates CAC in Dectin‐3‐deficient mice. [ABSTRACT FROM AUTHOR]

We present a three‐dimensional (3D) spatial reconstruction of coronary arteries based on fusion of intravascular optical coherence tomography (IVOCT) and digital subtraction angiography (DSA). Centerline of vessel in DSA images is exacted by multi‐scale filtering, adaptive segmentation, morphology thinning and Dijkstra's shortest path algorithm. We apply the cross‐correction between lumen shapes of IVOCT and DSA images and match their stenosis positions to realize co‐registration. By matching the location and tangent direction of the vessel centerline of DSA images and segmented lumen coordinates of IVOCT along pullback path, 3D spatial models of vessel lumen are reconstructed. Using 1121 distinct positions selected from eight vessels, the correlation coefficient between 3D IVOCT model and DSA image in measuring lumen radius is 0.94% and 97.7% of the positions fall within the limit of agreement by Bland–Altman analysis, which means that the 3D spatial reconstruction IVOCT models and DSA images have high matching level. [ABSTRACT FROM AUTHOR]

To know if a lightning discharge reaches the ground or remains within the thundercloud is critical for lightning safety as cloud‐to‐ground lightning poses the greatest threat to life and property. The current classification methods for most lightning detection networks, which are based on the classification of electromagnetic pulses produced by lightning, still have plenty of room to improve, including some known issues to be addressed. We present a machine‐learning approach to classify lightning discharges. The classification model used in this study is based on Support Vector Machines (SVMs). Compared with traditional multiparameter methods, our algorithm does not require extraction of individual pulse parameters and additionally provides a probability for each prediction. Using a representative lightning pulse data collected by the Cordoba Marx Meter Array in Argentina, we found the classification accuracy of our machine‐learning algorithm to be 97%, which is higher than that for the existing lightning detection networks. Plain Language Summary: Electromagnetic signals emitted by lightning can be detected by sensors that are hundreds of kilometers away. Those signals are used to distinguish if the lightning discharge reaches the ground or remains inside the cloud. Higher accuracy of lightning type classification can lead to a better assessment of lightning risk and is also beneficial to lightning climatology studies. We present a machine‐learning–based algorithm to classify lightning pulses. The accuracy of the algorithm is 97%, which is better than those for classification algorithms used by lightning detection networks. Key Points: The classification accuracy of the machine‐learning–based algorithm using a representative lightning pulse data set is 97%Unlike multiparameter classification algorithms, the extraction of pulse parameters is not needed for this machine‐learning algorithmThis algorithm provides a probability for each prediction, which is a valuable metric for prediction uncertainty [ABSTRACT FROM AUTHOR]

Jiangmen is one of the Guangdong‐Hong Kong‐Macao Greater Bay Areas with frequent commercial intercourse, which is responsible for human immunodeficiency virus type 1 (HIV‐1) rapid circulation and genetic evolution for recent years. As a novel HIV‐1 second‐generation recombinant was previously reported in Jiangmen but the systematic molecular epidemiological investigation was still unknown. A retrospective study on HIV‐1 genotypic characteristics and the emergence of transmitted drug resistance in this region was necessary. A total of 224 newly diagnosed HIV‐positive cases were randomly selected in Jiangmen City of Guangdong Province between 2018 and 2019. The partial gag (1080 bp), pol (840 bp), and env (460 bp) genes were amplified using nested polymerase chain reaction followed by sequencing. The phylogenetic and recombination analysis as well as HIV‐1 drug resistance were performed to surveillance. Sexual transmission was determined to be the major risk factor in Jiangmen. Phylogenetic analysis detected the genotypic distribution as follows: CRF01_AE (36.65%,70 of 191), CRF07_BC (32.46%, 62 of 191), CRF08_BC (4.71%, 9 of 191), CRF55_01B (5.24%, 10 of 191), CRF59_01B (3.14%, 6 of 191), subtype B (4.71%, 9 of 191), subtype C (1.05%, 2 of 191) as well as unique recombinant forms (12.04%, 23 of 191) consisted of seven recombinant patterns, which originated from multiple regions of China. Low‐level prevalence of Surveillance Drug Resistance Mutations (2.1%) were predicted but drug‐resistant mutations showed at a high level (15.4%) especially mutations in RT gene at position 179 were found to be the most frequent in the therapy‐naïve population. Our study highlighted the critical importance of monitoring the emerge of recombinant strains among newly diagnosed HIV‐1 individuals along with drug resistance regularly to prevent multi‐channel introduction and breakout of new HIV strains. Highlights: Our study highlighted the critical importance of monitoring the emerge of recombinant strains among newly diagnosed HIV‐1 individuals along with drug resistance regularly to prevent multi‐channel introduction and breakout of new HIV strains. [ABSTRACT FROM AUTHOR]

Ion migration induced interfacial degradation is a detrimental factor for the stability of perovskite solar cells (PSCs) and hence requires special attention to address this issue for the development of efficient PSCs with improved stability. Here, an "S‐shaped, hook‐like" organic small molecule, naphthalene diimide derivative (NDI‐BN), is employed as a cathode interface layer (CIL) to tailor the [6,6]‐phenylC61‐butyric acid methylester (PCBM)/Ag interface in inverted PSCs. By realizing enhanced electron extraction capability via the incorporation of NDI‐BN, a peak power conversion efficiency of 21.32% is achieved. Capacitance–voltage measurements and X‐ray photoelectron spectroscopy analysis confirmed an obvious role of this new organic CIL in successfully blocking ionic diffusion pathways toward the Ag cathode, thereby preventing interfacial degradation and improving device stability. The molecular packing motif of NDI‐BN further unveils its densely packed structure with π–π stacking force which has the ability to effectually hinder ion migration. Furthermore, theoretical calculations reveal that intercalation of decomposed perovskite species into the NDI clusters is considerably more difficult compared with the PCBM counterparts. This substantial contrast between NDI‐BN and PCBM molecules in terms of their structures and packing fashion determines the different tendencies of ion migration and unveils the superior potential of NDI‐BN in curtailing interfacial degradation. [ABSTRACT FROM AUTHOR]

Developing light‐harvesting materials with tunable emission colors is highly desirable in applications requiring a specific color on‐demand. The modulation in material composition, structures, and polymerization can provide a useful tool for producing a wide range of emission colors. However, controlling the color gamut in a ready‐made material remains a formidable challenge. Here, several germinate‐based phosphors are reported that provide precise dynamic emission color tuning in the visible color range through the optical multiplexing of lanthanides and other ion dopants, such as lead (Pb2+) and manganese (Mn2+). The emission gamut of the developed germinate‐based materials in the full visible color range can be tuned on demand by adjusting the excitation wavelength, thereby allowing dynamic synergistic multicolor, multitemporal, and multimodal integration with ready‐made materials. The multicolored photoluminescence property of the developed phosphors is related to the different interaction modes of dopants in the crystals. Furthermore, the applications of color‐tunable phosphors in multicolor display and anticounterfeiting are demonstrated. These findings provide valuable insights toward developing next‐generation smart luminescent materials and sensors. [ABSTRACT FROM AUTHOR]

The location accuracy of the U.S. National Lightning Detection Network (NLDN) has been evaluated using as ground‐truth rocket‐triggered lightning data or video records but only at a few specific locations. In this study, by using the NLDN data for the events attributable to lightning strikes to towers, the location error of the NLDN across the entire contiguous United States was evaluated for the first time. We found that, on average, the NLDN median location error reduced from 198 to 84 m after the 2013 NLDN upgrade. The location error at the periphery of the network is significantly larger than that in its interior. In the coastal regions, there is directional location bias toward the water. Simulation results suggest that the bias is related to the lengthening of field waveform front due to electromagnetic wave propagation over lossy ground coupled with the asymmetrical sensor configuration relative to the strike point (lack of offshore sensors). Key Points: NLDN location errors were estimated for CONUS using NLDN‐reported events that can be reasonably attributed to lightning strikes to towersAfter the 2013 upgrade, the median location error averaged over the interior of the network is 75 m versus 158 m for its peripheryThe directional location bias in coastal regions is related to propagation effects coupled with the lack of sensors over water [ABSTRACT FROM AUTHOR]

The Córdoba Argentina Marx Meter Array (CAMMA), consisting of 10 second‐generation Huntsville Alabama Marx Meter Array (HAMMA 2) sensors, operated at Córdoba, Argentina, during the Remote sensing of Electrification, Lightning, And Mesoscale/microscale Processes with Adaptive Ground Observations (RELAMPAGO) field campaign in late 2018. Initial results obtained from the campaign demonstrate that the new sensor is able to provide a significantly more detailed depiction of various lightning processes than its first generation. The lightning flashes mapped by the CAMMA and a colocated Lightning Mapping Array (LMA) were compared. The overall flash structures mapped by the CAMMA and the LMA look similar for most of the flashes. However, comparisons at smaller time scale show that the majority of CAMMA and LMA sources are not concurrent, indicating that unmatched sources were possibly due to different physical processes in leader propagation dominating different frequencies and differences in data processing and location techniques. Key Points: This paper showcases the new sensor's capability to map lightning processes like K processes and downward leaders in a CG flashThe flash structures mapped by the CAMMA using a hybrid technique and a colocated Lightning Mapping Array look similar for most flashesA large number of unmatched LF and VHF sources were possibly due to different physical processes and differences in location techniques [ABSTRACT FROM AUTHOR]

Prion‐like transcellular spreading of tau in Alzheimer's Disease (AD) is mediated by tau binding to cell surface heparan sulfate (HS). However, the structural determinants for tau–HS interaction are not well understood. Microarray and SPR assays of structurally defined HS oligosaccharides show that a rare 3‐O‐sulfation (3‐O‐S) of HS significantly enhances tau binding. In Hs3st1−/− (HS 3‐O‐sulfotransferase‐1 knockout) cells, reduced 3‐O‐S levels of HS diminished both cell surface binding and internalization of tau. In a cell culture, the addition of a 3‐O‐S HS 12‐mer reduced both tau cell surface binding and cellular uptake. NMR titrations mapped 3‐O‐S binding sites to the microtubule binding repeat 2 (R2) and proline‐rich region 2 (PRR2) of tau. Tau is only the seventh protein currently known to recognize HS 3‐O‐sulfation. Our work demonstrates that this rare 3‐O‐sulfation enhances tau–HS binding and likely the transcellular spread of tau, providing a novel target for disease‐modifying treatment of AD and other tauopathies. [ABSTRACT FROM AUTHOR]

With the increasing applications of high‐voltage direct current inverters in heavy‐load grids, commutation failures (CFs) pose a severe threat to the safe and stable operation of power systems. This study first sorts methods of CF inhibition into different categories and then investigates their effectiveness, adaptability and limitations. Considering the economic benefits and applicability, CF inhibition calls for integrated methods involving supplementary power devices, control strategies and prediction techniques. Finally, this study makes clear potential future research directions, suggesting first control potential is exploited by machine learning‐based control, and then auxiliary devices to be added if necessary. [ABSTRACT FROM AUTHOR]

Using high‐speed video cameras operating with framing rates of 20 and 525 kfps, we imaged the attachment process of a natural negative cloud‐to‐ground flash, occurring at a distance of 490 m. Nine upward leaders were observed. A total of 12 space stems/leaders in 47 steps of the downward negative stepped leader were captured. The two‐dimensional length of them was between 2.0 and 5.9 m, with an average of 3.0 m. The average interstep interval, step length, and two‐dimensional speed of the downward negative leader and that of upward positive leader were statistically analyzed. The last step of the downward negative leader making contact with the upward connecting leader was recorded. The two‐dimensional length of the final imaged gap between the tips of opposite‐polarity leaders was estimated to be about 13 m. Plain Language Summary: The lightning attachment process is still one of the most poorly documented lightning processes. This process consists of two phases: the development of one or more upward leaders extending from grounded objects toward the approaching downward leader and the so‐called breakthrough phase (final jump; e.g., Rakov & Tran, 2019, https://doi.org/10.1016/j.epsr.2019.03.018). As the characteristic time scale of the attachment process is as short as 1 ms or less, it is difficult to image the attachment process with sufficiently high temporal resolution. In this study, we present video records of the attachment process in natural lightning obtained with the highest to date framing rate. The results allow one to see the previously unresolved details of the attachment process needed for improving our understanding of lightning mechanisms. Moreover, researchers developing lightning leader models and lightning protection system designers may benefit from this work. Key Points: High‐speed video records of the attachment process in a natural lightning flash with interframe interval < 2 μs are presentedThe last step of the downward negative leader making contact with the upward positive connecting leader was imagedTwo‐dimensional length of the final imaged gap between the tips of opposite‐polarity leaders was estimated to be about 13 m [ABSTRACT FROM AUTHOR]

High‐speed video and electric field change data have been used to examine the initiation and propagation of 21 recoil leaders, 7 of which evolved into dart (or dart‐stepped) leaders (DLs) initiating return strokes and 14 were attempted leaders (ALs), in a Canton‐Tower upward flash. Three DLs and two ALs clearly exhibited bidirectional extension. Each DL was preceded by one or more ALs and initiated near the extremity of the positive end of the preceding AL. The positive end of each bidirectional DL generally appeared to be inactive (stationary) or intermittently propagated along the positive part of the preceding AL channel and extended into the virgin air. A sequence of two floating channel segments was formed ahead of the approaching positive end of one DL, causing its abrupt elongation. Plain Language Summary: In this paper, we present high‐speed video observations of recoil leaders (RLs) which were not obscured by the cloud. We examined the initial positions, morphology, and dynamics of RLs in a Canton‐Tower upward flash. Out of a total of 21 RLs, 7 evolved into dart (or dart‐stepped) leaders, attaching to the Tower and producing return strokes, and 14 failed to reach the Tower, that is, were attempted dart (or dart‐stepped) leaders. We infer that all the RLs were bidirectional with the negative end steadily extending toward the Tower and the positive end generally being stationary or showing intermittent propagation. Each dart (or dart‐stepped) leader initiated near the extremity of the positive end of the preceding bidirectional attempted leader. The positive end of one dart (or dart‐stepped) leader extended abruptly via connection of at least one floating channel to the positive channel tip. Key Points: Recoil leaders evolving into dart leaders producing return strokes and those failing to do so were studied in detailEach successful dart (or dart‐stepped) leader initiated near the extremity of the positive end of the preceding bidirectional attempted leaderThe positive end of one dart (or dart‐stepped) leader exhibited abrupt elongation via connection of at least one floating channel to the positive channel tip [ABSTRACT FROM AUTHOR]

A positive cloud‐to‐ground (+CG) lightning flash containing a single stroke with a peak current of approximately +310 kA followed by a long continuing current triggered seven upward lightning flashes from tall structures. The flashes were observed on 4 June 2016 at the Tall Object Lightning Observatory in Guangzhou, Guangdong Province, China. The optical and electric field characteristics of these flashes were analyzed using synchronized two‐station data from two high‐speed video cameras, one total‐sky lightning channel imager, two lightning channel imagers, and two sets of slow and fast electric field measuring systems. Three upward flashes were initiated sequentially in the field of view of high‐speed video cameras. One of them was initiated approximately 0.35 ms after the return stroke of +CG flash from the Canton Tower, the tallest structure within a 12‐km radius of the +CG flash, while the other two upward flashes were initiated from two other, more distant tall objects, approximately 18 ms after the +CG flash stroke. The initiation of the latter two upward flashes could be caused by the combined effect of the return stroke of +CG flash, its associated continuing current, and K process in the cloud. Each of these three upward flashes contained multiple downward leader/upward return stroke sequences, with the first leader/return stroke sequence of the second and third flashes occurring only after the completion of the last leader/return stroke sequence of the preceding flash. The total number of strokes in the three upward flashes was 13, and they occurred over approximately 1.5 s. Key Points: Seven upward lightning flashes were triggered by a 310‐kA +CG flashThree upward flashes, each containing downward leader/upward return stroke sequences, were studied in detailThe first leader/return stroke sequence of the second and third flashes occurred only after the completion of the last leader/return stroke sequence of the preceding flash [ABSTRACT FROM AUTHOR]

In this study, we found no association between maternal blood levels of carotenoids, vitamin A, and vitamin E at delivery with the development of allergen sensitization, eczema, rhinitis, and wheeze with use of nebulizer/inhaler in the offspring in first five years of life. To our knowledge, this is the first study with the longest follow-up of children, to have investigated relationships between objective measurements of carotenoids, vitamin A, and vitamin E in maternal blood with allergic outcomes in offspring up to five years old. The strengths of this study are the objective measurement of carotenoids, vitamin A, and vitamin E in maternal plasma, which are not subjected to recall bias. Vitamins A and E during pregnancy and allergy symptoms in an early childhood-lack of association with tobacco smoke exposure. [Extracted from the article]

Efficient transient simulation of large power grid is of great importance for system operation and dispatching, fault repetition, operator training etc. Online stability estimation and testing on system control and protection require hard real‐time performance of transient simulation. The conventional real‐time simulation, which splits an entire grid into sub‐grids and solves them in parallel, lacks generality for various case systems. This study proposes a new efficiency enhancement method without grid partitioning. Three key techniques are involved. First, parallel solving format is proposed to distribute two‐layer computational burdens into central processing unit cores in balance. Second, to calculate the fault changing the grid structure, the inverse current compensation is employed instead of re‐forming impedance matrix and repeating lower‐upper (LU) decomposition. Third, dual‐loop forward and backward substitutions to solve grid equations are modified to a single‐loop iteration, which further improves the computational efficiency. At last, the validity and effectiveness of the proposed method are verified by tests. [ABSTRACT FROM AUTHOR]

Interannual variability in the mesoscale eddy field in the Agulhas Return Current (ARC) of 32–42°S and 15–35°E is investigated based on satellite altimeter observations and state estimate from the Estimating the Circulation and Climate of the Ocean, Phase II from 1993 to 2016. It is found that the interannual modulation of eddy kinetic energy in the ARC region is externally mediated by the wind stress forcing that generates the westward propagating sea surface height anomalies across the South Indian Ocean subtropical gyre. The wind‐forced sea surface height anomalies influence the upstream Agulhas Current volume transports. By modulating the intensity of barotropic instability of the ARC mean flow centered around the retroflection region, the Agulhas Current inflow variability leads to the downstream interannual eddy kinetic energy fluctuations in the ARC region. Key Points: Interannual modulation of EKE in the ARC region is mediated by westward propagating SSH anomalies generated by basin‐wide wind stress forcingUpstream Agulhas Current inflow variability regulates the downstream interannual EKE fluctuations in the ARC regionBarotropic instability is the main energy source controlling the regional EKE variability Plain Language Summary: The interannual eddy kinetic energy modulations in the Agulhas Return Current region are investigated in this study on the basis of the satellite altimeter observations and the Estimating the Circulation and Climate of the Ocean, Phase II state estimate for the period of 1993–2016. The interannual eddy kinetic energy modulations in the Agulhas Return Current region are affected by the upstream Agulhas Current volume transports mainly via the barotropic instability. The wind stress curl forcing in the subtropical Indian Ocean is regarded as the major factor to modulate the Agulhas Current volume transport. [ABSTRACT FROM AUTHOR]

Abstract: Chiral ZIF‐8 hollow nanospheres with d‐histidine as part of chiral ligands (denoted as H‐ d‐his‐ZIF‐8) were prepared for separation of (±)‐amine acids. Compared to bulk d‐his‐ZIF‐8 without a hollow cavity, the prepared H‐ d‐his‐ZIF‐8 showed 15 times higher separation capacity and higher ee values of 90.5 % for alanine, 95.2 % for glutamic acid and 92.6 % for lysine, respectively. [ABSTRACT FROM AUTHOR]

Modular multilevel converters (MMCs) play a critical role in the future energy Internet pattern. Therefore, proper models for the simulation of complex systems with multiple MMCs are required. This study proposes a simplified equivalent model (SEM) based on the implicit trapezoidal method and Thevenin equivalent. The model can accurately simulate arm voltages of the MMC and is thus capable of simulating system‐level transients after faults and disturbances, circulating currents and subsynchronous oscillation components. Subsequently, a hybrid model combining SEM and a detailed equivalent model (DEM) is built to improve the overall simulation speed in scenarios where submodule‐level transients are mixed with system‐level ones. Finally, this study notes that the major difference between DEM and SEM results only from the voltage‐balancing cycle. An experiential formula is given to regulate SEM when the voltage‐balancing cycle is large, where the difference may become obvious/insufferable. [ABSTRACT FROM AUTHOR]

Organic semiconductor materials with high charge-carrier mobility and high luminescence are promising for fabricating high-performance organic light-emitting transistors and electrically pumped organic laser diodes. Some derivatives with an anthracene core show both characteristics; however, independently controlling the size and the thickness of single-crystal films is challenging. Here, 2D and 3D crystal formation is demonstrated by using an air-stable organic semiconductor, 2,6-bis[4-ethylphenyl]anthracene (BEPAnt). The shape of the single-crystal films can be changed from about 0.10 mm in diameter and 400 nm in thickness to 1.0 mm in diameter and 50 nm in thickness by controlling the growth conditions using saturation-supersaturation vapor pressure curves. The in-plane growth rate increases by ten times while the out-of-plane growth rate decreases to about 1/8 as the growth temperature increases from 210 to 250 °C. Single-crystal organic field-effect transistors based on BEPAnt show isotropic mobilities as high as 7.2 cm2 V−1 s−1. [ABSTRACT FROM AUTHOR]

A series of active-carbon-supported PdPb and PdCu bimetal catalysts were prepared for the selective semihydrogenation of alkynes in the liquid phase. The Pd0.33Pb0.67/C catalyst showed the best performance for various alkynes under mild reaction conditions (room temperature and ambient H2 pressure) and achieved 100 % conversion with 98 % selectivity to alkenes. In particular, over-hydrogenation was avoided at complete alkyne conversion. [ABSTRACT FROM AUTHOR]

Ex-situ Synchrotron X-Ray Absorption Spectroscopy, Ligand Effects, Nanoclusters, Palladium, Single-Atom Catalysts Keywords: Ex-situ Synchrotron X-Ray Absorption Spectroscopy; Ligand Effects; Nanoclusters; Palladium; Single-Atom Catalysts EN Ex-situ Synchrotron X-Ray Absorption Spectroscopy Ligand Effects Nanoclusters Palladium Single-Atom Catalysts 1 1 1 04/05/23 20230411 NES 230411 B The low-temperature conversion b of Pd nanoclusters into Pd single atoms with the assistance of Cl ligands is illustrated by Tao Ding, Xiaokang Liu, Manzhou Zhu, Tao Yao et al. in their Research Article (e202218630). Inside Cover: Ligand Assisted Thermal Atomization of Palladium Clusters: An Inspiring Approach for the Rational Design of Atomically Dispersed Metal Catalysts (Angew. [Extracted from the article]

Ex-situ Synchrotron X-Ray Absorption Spectroscopy, Ligand Effects, Nanoclusters, Palladium, Single-Atom Catalysts The Pd nanoclusters collapse when coordinated by Cl ligands, thus enabling the transformation to take place at low temperatures (400 °C). Keywords: Ex-situ Synchrotron X-Ray Absorption Spectroscopy; Ligand Effects; Nanoclusters; Palladium; Single-Atom Catalysts EN Ex-situ Synchrotron X-Ray Absorption Spectroscopy Ligand Effects Nanoclusters Palladium Single-Atom Catalysts 1 1 1 04/05/23 20230411 NES 230411 B The low-temperature conversion b of Pd nanoclusters into Pd single atoms with the assistance of Cl ligands is illustrated by Tao Ding, Xiaokang Liu, Manzhou Zhu, Tao Yao et al. in their Research Article (e202218630). [Extracted from the article]