Search

Magnetic reconnection occurs ubiquitously in the universe and is often invoked to explain fast energy release and particle acceleration in high-energy astrophysics. The study of relativistic magnetic reconnection in the magnetically dominated regime has surged over the past two decades, revealing the physics of fast magnetic reconnection and nonthermal particle acceleration. Here we review these recent progresses, including the magnetohydrodynamic and collisionless reconnection dynamics as well as particle energization. The insights in astrophysical reconnection strongly connect to the development of magnetic reconnection in other areas, and further communication is greatly desired. We also provide a summary and discussion of key physics processes and frontier problems, toward a better understanding of the roles of magnetic reconnection in high-energy astrophysics. [ABSTRACT FROM AUTHOR]

This study presents the design and implementation of a low-speed intrusion experiment under microgravity, with a strong motivation to support the pre-research of the Chinese asteroid exploration mission. In the experiment apparatus, we reconstructed an effective gravity of 10 - 2 g in a free-falling capsule in the drop tower. The simulant of regolith particles is processed using natural basalt and sorted using layered screens. The irregular shapes of the particles are retained to mimic the realistic regolith. A detailed description of the experimental system components and the full-cycle procedure is first presented, which gives 3.6 s of microgravity time for each trial. Repeatable controlled experiments are performed to characterize the dynamical responses of the simulant particles under centimeter-per second intrusion. The results reveal diverse responses that depend on different variables, and the mechanism of different responses is discussed based on theories of granular mechanics. This experimental study is expected to improve our understanding of the contact mechanics of regolith material, which will facilitate the operation design of future asteroid missions. [ABSTRACT FROM AUTHOR]

Background: Sleep deprivation (SD) is commonplace in modern society and there are large individual differences in the vulnerability to SD. We aim to identify the structural network differences based on diffusion tensor imaging (DTI) that contribute to the individual different vulnerability to SD. Methods: The number of psychomotor vigilance task (PVT) lapses was used to classify 49 healthy subjects on the basis of whether they were vulnerable or resistant to SD. DTI and graph theory approaches were used to investigate the topologic organization differences of the brain structural connectome between SD‐vulnerable and ‐resistant individuals. We measured the level of global efficiency and clustering in rich club and non‐rich club organizations. Results: We demonstrated that participants vulnerable to SD had less global efficiency, network strength, and local efficiency but longer shortest path length compared with participants resistant to SD. Lower efficiency was mainly distributed in the right insula, bilateral thalamus, bilateral frontal, temporal, and temporal lobes. Furthermore, a disrupted subnetwork was observed that consisted of widespread connections. Moreover, the vulnerable group showed significantly decreased strength of the rich club compared with the resistant group. The strength of rich club connectivity was found to be correlated negatively with PVT performance (r = −0.395, p = 0.005). We further tested the reliability of the results. Conclusion: The findings revealed that individual differences in resistance to SD are related to disrupted topologic efficiency connectome pattern, and our study may provide potential connectome‐based biomarkers for the early detection of the vulnerable degree to SD. [ABSTRACT FROM AUTHOR]

Background: Cervical cancer (CC) is a potential clinical application of PD-1/PD-L1 inhibitor. We aimed to study the mechanism of DNA mismatch repair (MMR) system regulating the expression of PD-L1 in CC through DNA methyltransferase (DNMTs). Methods: We collected pathological specimens from 118 cases of CC to analyze the relationship between PD-L1 expression and DNMTs in different MMR states. RNA interference (RNAi) technique was used to simulate the formation of CC cell line with MMR deficiency (dMMR) state, and subcutaneous tumor formation experiment was carried out in nude mice to verify the relationship between PD-L1 expression and DNMTs in MMR state. Results: The PD-L1 positive rate in 118 cases of CC was 58.47%, while the microsatellite instability (MSI) status accounted for 5.93%. There was a significant difference in the expression of PD-L1 between patients within the dMMR and MMR proficient (pMMR) groups (χ2 = 21.405, P < 0.001). Subcutaneous inoculation after infection of Siha cells led to successful tumorigenesis in nude mice, accompanied by a significant increase in the level of PD-L1 expression in the mouse tumors, while the expression level of MLH1 and MSH2 protein decreased significantly. We also found that PD-L1 expression was closely related to the expression of DNMTs. Conclusion: PD-L1 is universal expressed on the surface of CC cells, dMMR status enhances the expression of PD-L1 on the surface of CC cells, dMMR states of CC are related to the demethylation status of the PD-L1 gene promoter region. [ABSTRACT FROM AUTHOR]

Carbon aerogels (CAs) are emerging carbon-based cellular materials with high porosity, low density, and a variety of functions. The combination of all these unique properties contributes to their wide applications in flexible sensors, energy devices, acoustic devices, and environmental applications. However, their wide applications are strictly limited by poor mechanical robustness. The existing conflicts between mechanical robustness and the sparse network of porous materials have never received due attention. Good robustness could ensure structural integrity and performance stability for practical applications of aerogels. Here, we discuss recently emerged strategies for optimizing mechanical robustness, including cell-wall strengthening, cell-wall orientation, pore topology control, and joint reinforcement. Particularly, we conclude advanced design principles to achieve stretching elasticity of CAs without introducing intrinsically stretchable elastomers. In addition, we briefly overview the recent applications of robust CAs and provide an outlook on the open questions for obtaining more mechanically robust CAs. [ABSTRACT FROM AUTHOR]

In this paper, a new approach to visual geo‐localization for natural environments is proposed. The digital elevation model (DEM) data in virtual space is rendered and construct a panoramic skyline database is constructed. By combining the skyline database with real‐world image data (used as the "queries" to be localized), visual geo‐localization is treated as a cross‐modal image retrieval problem for panoramic skyline images, creating a unique new visual geo‐localization benchmark for the natural environment. Specifically, the semantic segmentation model named LineNet is proposed, for skyline extractions from query images, which has proven to be robust to a variety of complex natural environments. On the aforementioned benchmarks, the fully automatic method is elaborated for large‐scale cross‐modal localization using panoramic skyline images. Finally, the compound index is delicately designed to reduce the storage space of the positioning global descriptors and improve the retrieval efficiency. Moreover, the proposed method is proven to outperform most state‐of‐the‐art methods. [ABSTRACT FROM AUTHOR]

Image dehazing is always a hot topic in the field of computer vision since haze has significant impact on the imaging quality of camera. Therefore, many image dehazing methods have been proposed for the past decades. To help researchers who are new to this field quickly figure out the development history as well as the current status of image dehazing, this review analyzes some representative dehazing methods, evaluates their advantages and disadvantages, and most importantly, points out the best dehazing method from different viewpoints. A large quantity of experiments show that AECR-Net can be generally considered to be the best dehazing algorithm and Tarel method can be regarded as the best real-time dehazing method. Besides, the mainstream benchmark, metrics, challenges and opportunities for image dehazing are also discussed in this review. [ABSTRACT FROM AUTHOR]

Magnetic reconnection in the relativistic regime has been proposed as an important process for the efficient production of nonthermal particles and high-energy emission. Using fully kinetic particle-in-cell simulations, we investigate how the guide-field strength and domain size affect the characteristic spectral features and acceleration processes. We study two stages of acceleration: energization up until the injection energy γ inj and further acceleration that generates a power-law spectrum. Stronger guide fields increase the power-law index and γ inj, which suppresses acceleration efficiency. These quantities seemingly converge with increasing domain size, suggesting that our findings can be extended to large-scale systems. We find that three distinct mechanisms contribute to acceleration during injection: particle streaming along the parallel electric field, Fermi reflection, and the pickup process. The Fermi and pickup processes, related to the electric field perpendicular to the magnetic field, govern the injection for weak guide fields and larger domains. Meanwhile, parallel electric fields are important for injection in the strong guide-field regime. In the post-injection stage, we find that perpendicular electric fields dominate particle acceleration in the weak guide-field regime, whereas parallel electric fields control acceleration for strong guide fields. These findings will help explain the nonthermal acceleration and emission in high-energy astrophysics, including black hole jets and pulsar wind nebulae. [ABSTRACT FROM AUTHOR]

Rational engineering active sites and vantage defects of catalysts are promising but grand challenging task to enhance photoreduction CO2 to high value‐added C2 products. In this study, we designed an N,S‐codoped Fe‐based MIL‐88B catalyst with well‐defined bipyramidal hexagonal prism morphology via a facile and effective process, which was synthesized by addition of appropriate 1,2‐benzisothiazolin‐3‐one (BIT) and acetic acid to the reaction solution. Under simulated solar irradiation, the designed catalyst exhibits high C2H4 evolution yield of 17.7 μmol g−1⋅h, which has been rarely achieved in photocatalytic CO2 reduction process. The synergistic effect of Fe‐N coordinated sites and reasonable defects in the N,S‐codoped photocatalyst can accelerate the migration of photogenerated carriers, resulting in high electron density, and this in turn helps to facilitate the formation and dimerization of C−C coupling intermediates for C2H4 effectively. [ABSTRACT FROM AUTHOR]

Rational engineering active sites and vantage defects of catalysts are promising but grand challenging task to enhance photoreduction CO2 to high value‐added C2 products. In this study, we designed an N,S‐codoped Fe‐based MIL‐88B catalyst with well‐defined bipyramidal hexagonal prism morphology via a facile and effective process, which was synthesized by addition of appropriate 1,2‐benzisothiazolin‐3‐one (BIT) and acetic acid to the reaction solution. Under simulated solar irradiation, the designed catalyst exhibits high C2H4 evolution yield of 17.7 μmol g−1⋅h, which has been rarely achieved in photocatalytic CO2 reduction process. The synergistic effect of Fe‐N coordinated sites and reasonable defects in the N,S‐codoped photocatalyst can accelerate the migration of photogenerated carriers, resulting in high electron density, and this in turn helps to facilitate the formation and dimerization of C−C coupling intermediates for C2H4 effectively. [ABSTRACT FROM AUTHOR]

PiGF (Phosphor-in-glass film) with high color rendering was successfully prepared at a low sintering temperature. The influence of sintering temperature, the mass ratio of glass and phosphor, and different fluorescent layers on the luminescence properties of PiGF was systematically studied. It is of note that the "cyan cavity" is significantly reduced due to the addition of "cyan phosphor" (BaSi 2 O 2 N 2 :Eu2+). Under 455 nm blue light laser excitation, PiGF has the highest luminous efficiency of 94.55 lm/W and a white light composite PiGF with a correlated color temperature of 5500 K and a color rendering index of 95 can be obtained. In short, this work shows that the PiGF has great potential application in white light laser lighting. • The PiGF has a very high color rendering index, which can reach 95. • While maintaining a high color rendering index, the correlated color temperature is low, only about 5500 K. • First application of cyan phosphor (BaSi 2 O 2 N 2 :Eu2+) to laser lighting to fill in cyan glow. [ABSTRACT FROM AUTHOR]

The sustainability of biogas production from straws is limited by the collection, transportation, storage, and pretreatment of feedstocks. To address these constraints, this study investigated briquetting as a pretreatment strategy for rice straw (RS) to increase bioenergy generation. The results indicated that briquetted RS yielded 205.4 mL/g VS of methane, which was 11.7% higher compared to that produced by the untreated RS. The economic analysis revealed that the briquetting process had positive effects with a payback time of 3.4 y and an internal rate of return of 23.4%. It also reduced feedstock transportation and storage costs by 42.6%. Adding a NaOH treatment to the briquetting process increased methane production by 26.4% compared to untreated RS. However, the integration of briquetting with NaOH treatment might be an unprofitable method for processing RS. This became apparent when examining the production cost, which stood at 1.13 $/kg biomethane with an internal rate of return of 16.2%, representing an 8.7% increase and a 7.2% decrease, respectively, compared to the mono briquetting method. These results revealed that briquetting as a source pretreatment strategy can improve the productivity of straw biogas plants, thereby advancing the industry towards cleaner production. [Display omitted] • Briquetting, a source pretreatment strategy, improved straw biogas production. • The briquetting strategy integrates the collection and pretreatment of rice straw. • The proposed strategy reduced straw transportation and storage costs by 42.6%. • Adding an NaOH treatment reduced the profitability of a straw biogas plant. [ABSTRACT FROM AUTHOR]

The consequence of exposure to the dual environment of seawater sea sand concrete (SWSSC) on the inner surface and seawater (SW) on the outer surface on the durability of fibre reinforced plastic (FRP) confining tubes has received very limited research attention. The durability of FRPs fabricated with different fibre types was investigated for the application of SWSSC filled tubes and SWSSC-filled double-skin tubes exposed to the external environment of SW. The colour and shininess of carbon-fibre-reinforced polymer (CFRP) surfaces generally stayed unchanged even after 6 months of exposure to the dual environment, whereas basalt-fibre-reinforced polymer (BFRP) and glass-fibre-reinforced polymer (GFRP) tubes suffered degradation. The degradation led to a ~20–30% increase in pH; however, the pH increase in the external SW was more pronounced when the internal solution was SWSSC. The extent of degradation was greater in BFRP that in GFRP. The investigation also included a specialised investigation of the degradation at the fibre–matrix interface by fracturing specimens in liquid nitrogen. [ABSTRACT FROM AUTHOR]

An identification method is proposed for errors-in-variables (EIV) ARX model with input time-varying time-delays. A Markov chain is used to model varying time delays whose parameters are also estimated. The EIV system accounts for noises in both input and output. To estimate noise-free input, a linear state space model is used to describe input generation process and a Kalman smoother is adopted for its estimation. An expectation maximization algorithm is used to estimate ARX model parameters. A spinning process of polyester fiber and a continuous stirred tank reactor process are used to verify the effectiveness of the proposed approach. • Time-varying time-delays are considered for Errors-in-variables (EIV) system. • Kalman smoother is used to estimation the noise-free input. • The EM algorithm is used to estimate the EIV-TD system parameters and update the noise variance of the input data. • Two simulations are provided for performance evaluation. [ABSTRACT FROM AUTHOR]

The regulation of γ-aminobutyric acid (GABA) on plant anti-oxygenation and programmed cell death (PCD) in fresh-cut pumpkins was investigated. Exogenous GABA positively promoted GABA accumulation and alleviated oxidant damage in pumpkins tissue. Pumpkins treated with GABA showed lower electrolyte leakage, reactive oxygen species (ROS) and MDA content, while higher activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) as compared to the non-treated tissues. Our results also found that GABA treatment retarded DNA degradation and cytochrome c release and delayed the apoptosis of pumpkin cells. On the other hand, the inhibitor of GABA generation, 3-mercaptopropionic acid (3-MP) treatment not only accelerated oxidant damage, but also induced cell death involving chromatin condensation, DNA ladder and cytochrome c releasing. Taken together, our present research indicated that exogenous GABA could alleviate the wound-induced oxidative stress and PCD occurrence in fresh-cut pumpkins. [Display omitted] • Exogenous GABA alleviated oxidant damage in fresh-cut pumpkins. • 3-Mercaptopropionic acid treatment accelerated oxidant damage and induced PCD. • GABA involved the PCD event and delayed PCD process in fresh-cut pumpkins. [ABSTRACT FROM AUTHOR]

Phosphor-in-glass (PiG) is one of the most important spectral converters to overcome thermal effect in high-power white light-emitting diodes (LEDs). The Al 2 O 3 –SiO 2 –B 2 O 3 –ZnO–Na 2 O–Li 2 O glass was designed and sintered with Y 3 Al 5 O 12 :Ce3+ (YAG: Ce) phosphors at the low temperature of 650 °C to obtain YAG: Ce-PiG. The optimized YAG: Ce-PiG shows the white light of the luminous efficiency (LE), correlated color temperature (CCT) and chromaticity coordinate (CIE) of 177.5 lm/W, 6410 K and (0.31,0.34), respectively. The white LEDs (WLED) were fabricated by coupling the YAG: Ce-PiG with a blue light emitting chip, and the correlation between the luminescence properties, the thickness of PiG and the ratio of phosphors was investigated. More importantly, the WLEDs of a maximum luminous efficiency can reach up to 199.5 lm/W with the thickness of 0.35 mm. In addition, a structure with vacuum packaging technique based on the WLEDs lighting combined with sapphire as substrate was fabricated, which can effectively reduce the heat accumulation during the working process of WLEDs. Compared with normal non-vacuum packaging, the working temperature of WLEDs was reduced by about 35%, from 359.2 to 232.2 °C, with the novel vacuum packaging technique under 30W high-power chip and the luminous performance can still be maintained at 94.7%. In a word, the prepared YAG: Ce-PiG exhibits a great potential for application in high-power solid-state WLEDs. • The new glass matrix of Al 2 O 3 –SiO 2 –B 2 O 3 –ZnO–Na 2 O–Li 2 O was designed and the thermal quenching effect of PiG was alleviated. • The white LEDs fabricated using PiG with high thermal stability and luminous efficiency reach up to 199.5 lm/W. • The vacuum packaging technique can significantly reduce heat accumulation in high-power white light-emitting diodes by 35%. [ABSTRACT FROM AUTHOR]

In strongly magnetized astrophysical plasma systems, magnetic reconnection is believed to be the primary process during which explosive energy release and particle acceleration occur, leading to significant high-energy emission. Past years have witnessed active development of kinetic modeling of relativistic magnetic reconnection, supporting this magnetically dominated scenario. A much less explored issue in studies of relativistic reconnection is the consequence of three-dimensional dynamics, where turbulent structures are naturally generated as various types of instabilities develop. This paper presents a series of three-dimensional, fully kinetic simulations of relativistic turbulent magnetic reconnection (RTMR) in positronâ€"electron plasmas with system domains much larger than kinetic scales. Our simulations start from a force-free current sheet with several different modes of long-wavelength magnetic field perturbations, which drive additional turbulence in the reconnection region. Because of this, the current layer breaks up and the reconnection region quickly evolves into a turbulent layer filled with coherent structures such as flux ropes and current sheets. We find that plasma dynamics in RTMR is vastly different from its 2D counterpart in many aspects. The flux ropes evolve rapidly after their generation, and can be completely disrupted by the secondary kink instability. This turbulent evolution leads to superdiffusive behavior of magnetic field lines as seen in MHD studies of turbulent reconnection. Meanwhile, nonthermal particle acceleration and the timescale for energy release can be very fast and do not depend strongly on the turbulence amplitude. The main acceleration mechanism is a Fermi-like acceleration process supported by the motional electric field, whereas the nonideal electric field acceleration plays a subdominant role. We also discuss possible observational implications of three-dimensional RTMR in high-energy astrophysics. [ABSTRACT FROM AUTHOR]

In the contribution, magnesium hydroxides and graphene oxide were synergistically combined to prepare the chip-in-flakes nanohybrid (Mg(OH)2/GO, MGO) via one-step hydrothermal approach for improving fire retardancy of polypropylene. Various characterizations confirmed its composition, structure and morphology. The fire-retardant evaluations illustrated that limiting oxygen index (LOI) of PP composite with 50 wt.% MGO was improved to 27.8% with UL-94 V-0 rating compared with virgin PP (17.4%, no rating). In parallel, the peak heat release rate, total heat release and smoke production rate of PP/MGO (PMG) were reduced by 80.5%, 30.8% and 79.4% respectively. The mechanism investigation uncovered that the conspicuous fire retardancy and smoke suppression were credited to the synergistic effect between GO and Mg(OH)2 toward the optimized physical barrier. Furthermore, dynamic mechanical analysis (DMA) disclosed the highest modulus (8043 MPa) at -71 °C relative to 3236 MPa of pure PP. In viewpoint, hierarchical nano-flakes with synergistic effect offered an effective approach for the fire-safe polymer. [ABSTRACT FROM AUTHOR]

A new image dehazing algorithm based on adaptive sky region is proposed in this paper, which shows good fidelity in sky region and satisfying visual effect in non‐sky region. For robust sky segmentation, we propose a rough‐to‐fine method that can make a balance between efficiency and accuracy. Considering distribution of haze is inconsistent, we divide the input image into three parts and calculate their atmospheric lights respectively. To solve the problem of invalid dark channel prior, we make an improvement for the transmission estimation. Finally, image fusion is taken as a post processing that can solve the problem of partial darkness and ensure a visual pleasing result. The experimental results for both synthetic and natural hazy images demonstrate that our algorithm performs comparable or even better results than the state‐of‐the‐art methods in terms of various measurement indexes, such as the PSNR, SSIM, and so forth. Besides, the proposed algorithm can be also applied in FPGA platform due to the optimized performance. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Middle East respiratory syndrome (MERS) is caused by MERS‐CoV that infects both human and camel. Camel is supposed to be the natural reservoir for human infection while the sources for most of the primary human infection cases are still not known. We identified two conserved pyrimidine nucleotides that flank UAAU element in MERS‐CoV 5'‐UTR. These conserved pyrimidine nucleotides distinguish MERS‐CoVs into 3 types, that is, UUAAUU, CUAAUU and CUAAUC (referred to as U‐‐‐‐U, C‐‐‐‐U, and C‐‐‐‐C types, respectively). Human MERS‐CoV displays a genetic drift from U‐‐‐‐U, C‐‐‐‐U, to C‐‐‐‐C from 2012 to 2019. Camel virus displays a genetic drift from U‐‐‐‐U to C‐‐‐‐U with a time lag when compared with human virus. The discrepancy in genetic drift seems not to support the notion that camel serves as the only natural reservoir for human infection. [ABSTRACT FROM AUTHOR]

Objective: The symptom-related neurobiology characteristic of schizophrenia in the brain from a network perspective is still poorly understood, leading to a lack of potential biologically-based markers and difficulty identifying therapeutic targets. We aim to test the dysregulated cross-network interactions among the Salience Network (SN), Central Executive Network (CEN) and Default Mode Network (DMN) and how they contributed to different symptoms in schizophrenia patients.Methods: We examined network interactions among the SN, CEN and DMN in 76 patients with schizophrenia vs. 80 well-matched controls using dynamic causal modeling (DCM). We further analyzed the relation between network dynamics and Positive and Negative Syndrome Scale (PANSS).Results: We observed that the DMN, CEN and SN across healthy controls and schizophrenia patients showed several similarities within or between-network pattern in the resting state. Comparing schizophrenia to controls, SN-centered cross-network interactions were most significantly reduced. Crucially, the strength of connections from CEN subnetwork 1 to DMN subnetwork 1 was positively correlated with the Positive Score of PANSS. The connection from the DMN subnetwork 2 to CEN subnetwork 2 was negatively correlated with the Negative Score of PANSS.Conclusions: Our study provides strong evidence for the dysregulation among SN, CEN and DMN in a triple-network perspective in schizophrenia. The connection between DMN and CEN could be clinically-relevant neurobiological signature of schizophrenia symptoms. Our study indicated that the description of brain triple network hypothesis could be a novel and possible bio-marker for schizophrenia. [ABSTRACT FROM AUTHOR]

Aims: The brain function impairment induced by sleep deprivation (SD) is temporary and can be fully reversed with sufficient sleep. However, in many cases, long‐duration recovery sleep is not feasible. Thus, this study aimed to investigate whether a short nap after SD is sufficient to restore brain function. Methods: The data of 38 subjects, including resting state functional magnetic resonance imaging data collected at three timepoints (before SD, after 30 h of SD, and after a short nap following SD) and psychomotor vigilance task (PVT) data, were collected. Dynamic functional connectivity (DFC) analysis was used to evaluate changes in brain states among three timepoints, and four DFC states were distinguished across the three timepoints. Results: Before SD, state 2 (a resting‐like FC matrix) was dominant (48.26%). However, after 30 h SD, the proportion of state 2 dramatically decreased, and state 3 (still resting‐like, but FCs were weakened) became dominant (40.92%). The increased proportion of state 3 positively correlated with a larger PVT "lapse" time. After a nap, the proportions of states 2 and 3 significantly increased and decreased, respectively, and the change in proportion of state 2 negatively correlated with the change in PVT "lapse" time. Conclusions: Taken together, the results indicated that, after a nap, the cognitive function impairment caused by SD may be reversed to some extent. Additionally, DFC differed among timepoints, which was also associated with the extent of cognitive function impairment after SD (state 3) and the extent of recovery therefrom after a nap (state 2). [ABSTRACT FROM AUTHOR]

Chemically modified graphene is commonly used as a desensitizer and combustion catalyst for energetic composites. However, the interaction between polar functional groups on chemically modified graphene and energetic ionic materials has not been explored systematically. Herein, we use graphene oxide (GO) with different oxidation degrees and dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) as experimental systems to investigate the effect of oxygen-containing functional groups of GO on the pyrolysis mechanism of energetic ionic materials. The experimental results show that the thermal decomposition of TKX-50 is affected by different oxidation degrees of GO, among which the highly oxidized GO (HGO) has the greatest effect. The thermal decomposition temperature of GO/TKX-50 composites decrease with the increase of oxygen-containing group content. The decomposition products of GO/TKX-50 composites are consistent with those of TKX-50, but the content of gas products changed. We argue that the interaction between the oxygen-containing groups of GO and TKX-50 controls the pyrolysis mechanism by promoting the transfer of protons in hydroxyl, (NH3OH)+, and (NH4)+, at least in the context of oxygen-containing functional groups. This work provides a route to manipulate the thermal decomposition temperature and gaseous product of the final compound through functional group content, which is helpful to study the polar functional group of chemically modified graphene for the modification of energetic materials. [ABSTRACT FROM AUTHOR]

• A SPMM with eight stable equilibrium states is proposed. • The kinetostatic model and the multi-stability topologies of SPMM are developed. • The stabilities and switching paths are verified by experiments. A multi-stable flexible mechanism is a mechanical device that can switch to different stable equilibrium states under external power. Most existing multi-stable mechanisms are achieved by splicing bi-stable mechanisms. This paper proposes a novel Spatial Parallel Multi-stable Mechanism (SPMM) without bi-stable mechanisms connected, which even could achieve eight stable equilibrium states and meanwhile contain bi-stable mechanisms' advantages such like simple structure and reliable abilities. To identify the equilibrium states, the paper develops a kinetostatic model using the Energy-Kinematics Differential Equations (EKDE) for the proposed SPMM. Based on the equilibrium states, the multi-stability topologies are drawn referring to direct groups, including the distribution of various equilibrium states and the switching paths between every two stable states. At last, the paper shows the experimental results of a 3D printed prototype and verify the eight-stability behaviors and the switching paths through unstable equilibrium states. A concept of the application in deformable cable protection shell using the SPMM is introduced. [ABSTRACT FROM AUTHOR]

• A design method of parallel flexible mechanisms is proposed. • Principles of stiffness superposition and joint type determination are deduced. • A design example of the RCC and the final structure are presented. Parallel flexible mechanisms with joints can better avoid stress concentration and achieve large motion range compared with integrated-structure ones. However, because of the lack of a mathematical model that can describe the stiffness contribution from the joints to the whole mechanism, the mechanism design is difficult and needs to be addressed. This paper proposes a synchronous design method involving stiffness and topology for parallel flexible mechanisms. To introduce and explain this method, this paper deduces two fundamental principles, namely, "Linear Stiffness Superposition Principle (LSSP)" and "Joint Type Determination Principle (JTDP)", and their deduction processes serve as the cores of the design method. To verify the method's effectiveness, a design process of a Remote Central Compliance (RCC) is presented as an example. [ABSTRACT FROM AUTHOR]

• This paper proposes a structure of a planar three-limb flexible mechanism. • The determination of equilibrium and stability by contour maps is introduced. • The variation of the multi-stability topology of the mechanism is analyzed. In general, the classical multi-stable mechanisms are made of single-loop bi-stable mechanism elements, but this paper proposes a novel structure of a planar three-limb flexible mechanism whose multi-stability is dependent on the structure parameters. The structure of this flexible mechanism is ingeniously designed to have a large selection range of the original limb length, resulting in the variation of the multi-stability distribution and the possible switching paths. To analyze the variation of this flexible mechanism, the paper introduces a method avoiding computational singularity to determine the stability by contour map and a method to draw the multi-stability topology to seek for the possible switching paths. Using these methods, the paper presents the variation of the multi-stability topology of an axisymmetric and two mirror-symmetric planar three-limb flexible mechanisms as the original length of the limbs increases. The results shows the mulita-stability of this flexible mechanism can be determined by the original length of the limbs and limb arrangement. The whole statements provide a theoretical basis for designing and applying such type of flexible multi-stable mechanism. [ABSTRACT FROM AUTHOR]

Summary: Trachactinolaimus nanjingensis n. sp. isolated from mosses at the Yangshan Quarry Park in Nanjing, P.R. China, is described. It is characterised by 3.01 (2.64-3.42) mm long female and 2.84 (2.50-3.22) mm long male, four onchia with numerous mural denticles (>100), vulva with a transverse slit, 15-19 contiguous ventromedian supplements, spicules length of 61.5 (54.6-64.3) μ m, and female and male both having long tail, with c′ values equal to 5.0-9.2 and 2.3-3.5, respectively. The new species was morphologically compared with T. brevicaudatus , T. dominicus , T. montanus and T. radulatus. The sequences of 18S and 28S rRNA genes of the new species were obtained using regular PCR amplification, while the ITS and mt COI sequences were extracted from the whole genome sequencing assembly. The phylogenetic relationships of the new species were reconstructed using 18S and 28S sequences and the status of the new species was discussed. The 18S and 28S sequences of a population of genus Westindicus recovered during the present study were also obtained. This is the first time to present the ITS and mt COI sequences of family Actinolaimidae. [ABSTRACT FROM AUTHOR]

• The prediction bias is mainly caused by data imbalance. • Curriculum coefficients are useful for mining hard samples and improving model generalization. • Teacher-student network ensures unbiased glaucoma diagnoses and evidence map predictions. • The evidence map output by the student network can provide more detailed information. Glaucoma is a disease that causes irreversible damage to the optic nerve. Research on accurate automatic screening algorithms is essential for the prevention and treatment of glaucoma. However, due to the imbalance of existing datasets and the existence of some hard samples that accompany other diverse and complex fundus diseases, the performance of current glaucoma screening algorithms is limited. In addition, the lack of interpretability also makes it difficult for the current algorithms to meet the requirements of clinical applications. In this paper, we propose a new multitask curriculum learning framework (MTCLF) for unbiased glaucoma screenings and visualizations of model decision-making areas. MTCLF is a teacher-student framework. The teacher network is used to generate the label evidence map. The student network can diagnose glaucoma and predict the evidence map at the same time with the well-designed dual-branch CNN structure and collaborative learning module. We design two curriculum coefficients θ and σ to guide the training process of the student network in the sample space so that the student network can adaptively balance the sample contribution, reduce the prediction bias and mine hard samples. The experimental results show that the accuracy, sensitivity, specificity, AUC and F 2 -score of MTCLF based on the LAG dataset for glaucoma diagnoses are 0.967, 0.961, 0.970, 0.996, and 0.958, respectively. These results are superior to those of the state-of-the-art methods. MTCLF not only achieves the best performance for unbiased glaucoma diagnoses but also generates a reliable evidence map to help clinicians explore fine lesion areas. [ABSTRACT FROM AUTHOR]

• Dilated convolutions ensure better feature transfer and accurate classification that result in a sensitivity boost. • Dilated convolutions serve as the main constituents of decoder, encoder blocks and skip connections. • Dilated convolutions of different rates are more effective at capturing dynamically complex blood vessels. • Proposed Weighted multi-output fusion retrieves high fidelity vascular map by extracting critical features from each output block. Retinal image segmentation can help clinicians detect pathological disorders by studying changes in retinal blood vessels. This early detection can help prevent blindness and many other vision impairments. So far, several supervised and unsupervised methods have been proposed for the task of automatic blood vessel segmentation. However, the sensitivity and the robustness of these methods can be improved by correctly classifying more vessel pixels. We proposed an automatic, retinal blood vessel segmentation method based on the U-net architecture. This end-to-end framework utilizes preprocessing and a data augmentation pipeline for training. The architecture utilizes multiscale input and multioutput modules with improved skip connections and the correct use of dilated convolutions for effective feature extraction. In multiscale input, the input image is scaled down and concatenated with the output of convolutional blocks at different points in the encoder path to ensure the feature transfer of the original image. The multioutput module obtains upsampled outputs from each decoder block that are combined to obtain the final output. Skip paths connect each encoder block with the corresponding decoder block, and the whole architecture utilizes different dilation rates to improve the overall feature extraction. The proposed method achieved an accuracy: of 0.9680, 0.9694, and 0.9701; sensitivity of 0.8837, 0.8263, and 0.8713; and Intersection Over Union (IOU) of 0.8698, 0.7951, and 0.8184 with three publicly available datasets: DRIVE, STARE, and CHASE, respectively. An ablation study is performed to show the contribution of each proposed module and technique. The evaluation metrics revealed that the performance of the proposed method is higher than that of the original U-net and other U-net-based architectures, as well as many other state-of-the-art segmentation techniques, and that the proposed method is robust to noise. [ABSTRACT FROM AUTHOR]

• Mannose delayed the decline of chlorophyll content. • Mannose regulated the gene expressions of chlorophyll catabolic enzymes. • Mannose retarded the PCD in broccoli by a mitochondria-dependent pathway. The effect of mannose treatment on chlorophyll catabolism and programmed cell death (PCD) in broccoli florets during storage at 20 ℃ has been investigated. The results showed that mannose treatment efficiently restrained chlorophyll degradation in broccoli florets via regulating chlorophyll catabolism genes (BoPPH, BoPAO, BoRCCR, BoSGR1 and BoSGR2). Meanwhile, mannose treatment efficiently suppressed the occurrence of PCD through the mitochondria-dependent pathway in broccoli florets. Less reactive oxygen species content observed in mannose-treated broccoli florets delayed the increase of mitochondrial membrane potential and inhibited unfolding of mitochondria permeability transition pore, which was associated with the inhibition of cytochrome c liberation in mitochondria and the maintenance of high levels of cytochrome c/a and the ratio of Ca2+ content, the activities of cytochrome c oxidase and alternative oxidase. These results suggested that mannose treatment inhibited senescence of broccoli florets through suppressing the chlorophyll degradation and the appearance of PCD. [ABSTRACT FROM AUTHOR]

Inspired by the structure of corn, a NiFe Prussian blue analogue nanocages decorated magnesium hydroxide composite was synthesized for the first time using magnesium hydroxide rods (RMH) as the "corn cob", a Prussian blue analogue (PBA) as the "corn kernels" and polydopamine (PDA) as the membrane linking RMH and PBA. Subsequently, the RMH@PDA@PBA composite was introduced into epoxy resin (EP) to improve its fire retardancy and mechanical properties. The composition, structure and morphology of the RMH@PDA@PBA-incorporated EP composite were investigated. The tensile strength of EP with 3 wt.% RMH@PDA@PBA reached 41.77 MPa, which is higher than that of neat EP (40.51 MPa). The fire-retardant assessments illustrated that the limiting oxygen index and vertical burning tests (UL-94) of EP composite with 3 wt.% RMH@PDA@PBA progressed to 32.3% and the V-0 level as compared to those of virgin EP (24.4% and no rating). In addition, as compared to virgin EP, the peak heat release rate, peak smoke production rate, total heat release at 200 s and total smoke production at 200 s of EP/3RMH@PDA@PBA decreased by 43.1%, 50.0%, 43.9% and 56.3%, respectively. The investigation of the underlying mechanism revealed that the flame retardancy and smoke suppression of EP/3RMH@PDA@PBA were attributed to the endothermic decomposition of RMH, "gauze barrier" mechanism of MgO/FeO, catalytic charring effect of Fe derivatives (MgO/FeO, FeNi 3 , Fe 5 C 2 , Fe 2 N, etc.) and free radical scavenging effect of PBA@Fe[Ⅲ]. Thus, this study on bio-inspired hierarchical nanostructures paves a new pathway for the efficient production of fire-safe polymers. [Display omitted] • A novel low-cost RMH@PDA@PBA with corn structure was first prepared. • The RMH@PDA@PBA significantly improves the fire safety of epoxy resin. • 3 wt.% RMH@PDA@PBA endowed epoxy resin with UL-94 V-0 and reduced smoke production. • The addition of RMH@PDA@PBA enhanced the mechanical properties of epoxy resin. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanohybrids GPM with different GO content were synthesized via one-step hydrothermal method. • GPM improved the fire safety of EP with significantly reducing the PHRR, THR, PCOP and TSP with only 3 wt% loading. • Excellent fire safety of EP/GPM attributed to the comprehensive synergistic effect of Mg(OH) 2 and GO. • GPM exhibited superior mechanical properties compared to that of Mg(OH) 2. With the rapid development of Graphene based hybrid materials, various of them were fabricated to improve the fire safety of EP. However, the effect of GO content in the hybrid material on flame retardancy of EP composites is rarely reported. In order to find the optimal ratio of GO/Mg(OH) 2 , platelet-like Mg(OH) 2 functioned graphene (GPM) were synthesized with diverse content GO substance and then presented into EP resin for improving its fire retardancy. Various characterizations confirmed its composition, structure and morphology. The incorporation of GPM contains about 1% GO increased the tensile strength by 31.6% compared to that of untreated Mg(OH) 2. The GPM contains about 5% GO exhibited the finest fire safety in various EP composites. The fire-retardant assessments illustrated that the limiting oxygen index (LOI) of EP composite with 3 wt% GPM progressed to 27.8% compared with virgin EP (24.4%). In parallel, compared to virgin EP, the peak heat release rate, peak smoke production rate, total smoke production and peak CO production rate of EP/5GPM were diminished by 50.9%, 44.0 %, 25.5% and 53.1%, separately. The mechanism investigation revealed that the prominent flame retardancy and smoke suppression were attributed to the physical barrier of GO, the endothermic decomposition of Mg(OH) 2 , the barrier effect of MgO and synergistic effect between GO and Mg(OH) 2 toward the optimized carbonization. In perspective, hierarchical platelet structure with synergistic effect offered an effective approach for the fire-safe polymer. [ABSTRACT FROM AUTHOR]

The sustainable development of tungsten and molybdenum resources requires a new clean and recyclable separation technology. This work proposes a recyclable clean separation technology of tungsten and molybdenum with a porous amine resin. The resin was well prepared by assembling amine groups on trioctylamine (TOA) and the porous resin matrix D301 by the dipping method. Here, pH 7.8, temperature 25 °C, and reaction time 240 min was used as optimum condition, resulting in the highest sorption capacity 236 mg g−1, and it has a good cycle performance, exhibiting a retention rate of 90% after five cycles. Experimental spectroscopy combined theoretical calculation confirmed that this sustainable sorption behavior is substantially related to the amine functional groups on the resin. Experimental spectroscopy illustrated that the Cl− ions in the amine resin and the MoS 4 2− ions were subjected to ion exchange. Theoretical investigations further confirm that the sorption site is at the N atoms, the sorption behavior is chemical binding with the binding energy −0.055 Ha, and the bonding method is the s orbit of the N atoms in the amine resin hybridized with the s orbit of the S atoms in the amine resin. Owing to such an excellent performance in the selective sorption of molybdenum from the tungstate solution, the amine resin is greatly promising in the tungsten and molybdenum waste recovery field. [Display omitted] • A porous amine resin with 236 mg g−1 sorption capacity for molybdenum was prepared. • Experimental spectra confirmed the ion exchange mechanism between Cl− and MoS 4 2−. • Theoretical calculations determined the sorption site and bonding behavior. [ABSTRACT FROM AUTHOR]

Objectives. Schizophrenia (SCZ) is associated with disrupted functional brain connectivity, and antipsychotic medications are the primary and most commonly used treatment for schizophrenia. However, not all patients respond to antipsychotic medications. Methods. The study is aimed at investigating whether the graph-theory-based degree centrality (DC), derived from resting-state functional MRI (rs-fMRI), can predict the treatment outcomes. rs-fMRI data from 38 SCZ patients were collected and compared with findings from 38 age- and gender-matched healthy controls (HCs). The patients were treated with antipsychotic medications for 16 weeks before undergoing a second rs-fMRI scan. DC data were processed using DPABI and SPM12 software. Results. SCZ patients at baseline showed increased DC in the frontal and temporal gyrus, anterior cingulate cortex, and precuneus and reduced DC in bilateral subcortical gray matter structures. However, those abnormalities showed a clear renormalization after antipsychotic medication treatments. Support vector machine analysis using leave-one-out cross-validation achieved a correct classification rate of 84.2% (sensitivity 78.9%, specificity 89.5%, and area under the receiver operating characteristic curve (AUC) 0.925) for differentiating effective subjects from ineffective subjects. Brain areas that contributed most to the classification model were mainly located within the bilateral putamen, left inferior frontal gyrus, left middle occipital cortex, bilateral middle frontal gyrus, left cerebellum, left medial frontal gyrus, left inferior temporal gyrus, and left angular. Furthermore, the DC change within the bilateral putamen is negatively correlated with the symptom improvements after treatment. Conclusions. Our study confirmed that graph-theory-based measures, combined with machine-learning algorithms, can provide crucial insights into pathophysiological mechanisms and the effectiveness of antipsychotic medications. [ABSTRACT FROM AUTHOR]

The incorporation of Sc3+ can stabilize calcite-phase LuBO3:Ce3+ to grow large-sized single crystals but leads to the significant degradation of scintillation performance. In the present work, alkali metal ion (A+ = Li+, Na+, K+)-incorporated (Lu, A, Sc)BO3:Ce was rapidly synthesized in batches via a high-throughput sol–gel method. The aliovalent substitution of Lu3+ with A+ is balanced by the generation of oxygen vacancies by forming complexes. Thanks to the increased oxygen vacancies, the luminescence and XEL intensity of (Lu, Li, Sc)BO3:Ce are significantly enhanced by 2.2 times and 1.9 times, respectively. Further, the incorporation of A+ is attributed to the improved transition efficiency of charge carriers. The prepared scintillation screen fabricated with LASBO:Ce and PMMA shows that the spatial resolution can reach 8.6 lp mm−1, indicating its potential application in efficient and low-cost non-destructive X-ray detection. This work is of great significance in improving the luminescence and scintillation performance of (Lu, Sc)BO3:Ce single crystals and thin films and their application in the scintillation field. [ABSTRACT FROM AUTHOR]

Particle acceleration during magnetic reconnection is a long-standing topic in space, solar, and astrophysical plasmas. Recent 3D particle-in-cell simulations of magnetic reconnection show that particles can leave flux ropes due to 3D field-line chaos, allowing particles to access additional acceleration sites, gain more energy through Fermi acceleration, and develop a power-law energy distribution. This 3D effect does not exist in traditional 2D simulations, where particles are artificially confined to magnetic islands due to their restricted motions across field lines. Full 3D simulations, however, are prohibitively expensive for most studies. Here, we attempt to reproduce 3D results in 2D simulations by introducing ad hoc pitch-angle scattering to a small fraction of the particles. We show that scattered particles are able to transport out of 2D islands and achieve more efficient Fermi acceleration, leading to a significant increase of energetic particle flux. We also study how the scattering frequency influences the nonthermal particle spectra. This study helps achieve a complete picture of particle acceleration in magnetic reconnection. [ABSTRACT FROM AUTHOR]

The information unavailability of a global navigation satellite system (GNSS) for geo‐localization in many military and tourism applications implies the need to employ other applicable types of information, such as automatic image‐based location recognition. Unlike most existing localization methods that use GNSS information to locate an initial position, this paper proposes an automatic geo‐localization framework that does not require GNSS data. The proposed framework is a two‐stage pipeline that uses a query image and digital elevation model (DEM) data as input. The authors frame automatic geo‐localization without GNSS recordings as a skyline matching problem. By extracting the skyline from the DEM data and query images, the query image can be localized by matching the query skyline feature to the DEM skyline database. It has been demonstrated that this low‐cost approach can perform efficiently in mountainous or hilly areas to produce reliable localization results. The system was tested on 50 testing site points within a large‐scale area (China, 202.6 km2), and an average position error of 43.13 m was detected within 4.5 s. [ABSTRACT FROM AUTHOR]

Background: Diabetic cardiomyopathy (DCM) is a serious complication in patients with type 1 diabetes mellitus (T1DM), which still lacks adequate therapy. Irisin, a cleavage peptide off fibronectin type III domain-containing 5, has been shown to preserve cardiac function in cardiac ischemia–reperfusion injury. Whether or not irisin plays a cardioprotective role in DCM is not known. Methods and results: T1DM was induced by multiple low-dose intraperitoneal injections of streptozotocin (STZ). Our current study showed that irisin expression/level was lower in the heart and serum of mice with STZ-induced TIDM. Irisin supplementation by intraperitoneal injection improved the impaired cardiac function in mice with DCM, which was ascribed to the inhibition of ferroptosis, because the increased ferroptosis, associated with increased cardiac malondialdehyde (MDA), decreased reduced glutathione (GSH) and protein expressions of solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4), was ameliorated by irisin. In the presence of erastin, a ferroptosis inducer, the irisin-mediated protective effects were blocked. Mechanistically, irisin treatment increased Sirtuin 1 (SIRT1) and decreased p53 K382 acetylation, which decreased p53 protein expression by increasing its degradation, consequently upregulated SLC7A11 and GPX4 expressions. Thus, irisin-mediated reduction in p53 decreases ferroptosis and protects cardiomyocytes against injury due to high glucose. Conclusion: This study demonstrated that irisin could improve cardiac function by suppressing ferroptosis in T1DM via the SIRT1-p53-SLC7A11/GPX4 pathway. Irisin may be a therapeutic approach in the management of T1DM-induced cardiomyopathy. [ABSTRACT FROM AUTHOR]

Membrane separation plays a crucial role in the current increasingly complex energy environment. Membranes prepared by metal–organic framework (MOF) materials usually possess unique advantages in common, such as uniform pore size, ultra‐high porosity, enhanced selectivity and throughput, and excellent adsorption property, which have been contributed to the separation fields. In this comprehensive review, we summarize various designs and synthesized strategies of free‐standing MOF and composite MOF‐based membranes for water treatment. Special emphases are given not only on the effects of MOF on membrane performance, removal efficiencies, and elimination mechanisms, but also on the importance of MOF‐based membranes for the applications of oily and micro‐pollutant removal, adsorption, separation, and catalysis. The challenges and opportunities in the future for the industrial implementation of MOF‐based membranes are also discussed. [ABSTRACT FROM AUTHOR]

The flashover failure and damage of polypropylene (PP) and polyester (PET) films under nanosecond current pulses were experimentally investigated. A nanosecond pulse current test platform was established to study the flashover characteristics, performance degradation, and structural damage of dielectric films under repeated nanosecond current pulses. The accumulation and emission of surface charge influenced by field distortion and trap distribution were analyzed to clarify the mechanism by which the flashover voltage increases linearly with gas pressure at low pressure and saturates at high pressure. The significant effects of pulse energy, gas pressure, and discharge gap on film damage behavior were investigated. The damage pattern of PP and PET films includes surface deformation, reduced flash-voltage tolerance, molecular chain breakage, and group shedding. The damage of PP films is manifested as fine furrows, while PET corresponds to mountainous bumps. With the increasing number of discharges, the breakdown voltage of PP films decreased significantly, while the flash tolerance performance of PET films was more stable. Under the conditions of high pulse current amplitude, small discharge gap, and low air pressure, the damage degree of the film intensifies, which is characterized by severe destruction to the molecular structure and a significant decrease in flashover withstand voltage. Polymer films, flashover, nanosecond current pulses; performance degradation; microstructural damage. [ABSTRACT FROM AUTHOR]

Particles are accelerated to very high, non-thermal energies during explosive energy-release phenomena in space, solar, and astrophysical plasma environments. While it has been established that magnetic reconnection plays an important role in the dynamics of Earth's magnetosphere, it remains unclear how magnetic reconnection can further explain particle acceleration to non-thermal energies. Here we review recent progress in our understanding of particle acceleration by magnetic reconnection in Earth's magnetosphere. With improved resolutions, recent spacecraft missions have enabled detailed studies of particle acceleration at various structures such as the diffusion region, separatrix, jets, magnetic islands (flux ropes), and dipolarization front. With the guiding-center approximation of particle motion, many studies have discussed the relative importance of the parallel electric field as well as the Fermi and betatron effects. However, in order to fully understand the particle acceleration mechanism and further compare with particle acceleration in solar and astrophysical plasma environments, there is a need for further investigation of, for example, energy partition and the precise role of turbulence. [ABSTRACT FROM AUTHOR]

Coaxial peaking capacitor is a key component in high-altitude electromagnetic pulse (EMP) simulators with fast front pulse output. It poses significant technical and engineering challenges in limiting radiation field amplitude and test space. This paper presents the design and testing of a 180 pF, 3 MV coaxial peaking capacitor with improved insulation performance. In the insulation design, the length of the dielectric film is extended to reduce the background electric field on the flashover path. The electric field threshold obtained from image diagnosis is used as a reference. During capacitor testing, the insulation characteristics are diagnosed using both direct and indirect methods. The voltage measured by a D-dot probe, the output waveform of the Marx generator in the primary source, and the radiation field waveform are analyzed to understand the flashover characteristics of the capacitor and to improve the reliability of the test results. The experimental results demonstrate that the peaking capacitor can operate stably at 3.0 MV. If flashover occurring on the dropping edge of the pulse is permitted, the operating voltage can be greater than 3.7 MV without significantly affecting the radiation field waveform. The analysis on the surface flashover morphology of the peaking capacitor reveals that the flashover mainly occurs at the dropping edge of the capacitor's waveform, indicating that the damage to the film is not serious. This research significantly increases the working voltage of coaxial peaking capacitors and contributes to the development of high-altitude EMP simulation technology. [ABSTRACT FROM AUTHOR]

The development of renewable, hydrophobic, and biodegradable intelligent packaging materials as an alternative to petroleum-based plastic products has become a new research focus in recent years, but remains a challenge. Herein, regenerated cellulose/curcumin composite films were fabricated by dispersing hydrophobic curcumin uniformly in a hydrophilic cellulose matrix using an aqueous alkali/urea solvent based on the pH-driven principle of curcumin. In addition, a unilateral hydrophobic modification was carried out using chemical vapor deposition of methyltrichlorosilane to obtain Janus structure. The composite films exhibited high transparency in the visible light spectrum, excellent antioxidation, thermal stability, mechanical strength, gas barrier properties, and antibacterial activity. Furthermore, the films demonstrated the capability to lower the overall levels of volatile basic nitrogen in stored fish. The color of the films shifted from a pale yellow to a reddish-brown over time during storage. The composite films can be completely degraded after approximately 98 days in soil with an average environmental temperature of 29 °C. This work provided a facile strategy to prepare biodegradable cellulose/curcumin films with Janus structure as packaging materials which could preserve the freshness of food products while offering visual monitor of their freshness in real-time. [Display omitted] [ABSTRACT FROM AUTHOR]

Smartphone-assisted fluorescence and colorimetric methods for the on-site detection of Hg2+ and Cl− were established based on the oxidase-like activity of the Au–Hg alloy on the surface of Au/Cu/Ti3C2 NSs. The Au nanoparticles (NPs) were constructed via in-situ growth on the surface of Cu/Ti3C2 NSs and characterized by different characterization techniques. After the addition of Hg2+, the formation of Hg–Au alloys could promote the oxidization of o-phenylenediamine (OPD) to generate a new fluorescence emission peak of 2,3-diaminopenazine (ADP) at 570 nm. Therefore, a turn-on fluorescence method for the detection of Hg2+ was established. As the addition of Cl− can influence the fluorescence of ADP, the fluorescence intensity was constantly quenched to achieve the continuous quantitative detection of Cl−. Therefore, a turn-off fluorescence method for the detection of Cl− was established. This method had good linear ranges for the detection of Hg2+ and Cl− in 8.0–200.0 nM and 5.0–350.0 µM, with a detection limit of 0.8 nM and 27 nM, respectively. Depending on the color change with the detection of Hg2+ and Cl−, a convenient on-site colorimetric method for an analysis of Hg2+ and Cl− was achieved by using digital images combined with smartphones (color recognizers). The digital picture sensor could analyze RGB values in concentrations of Hg2+ or Cl− via a smartphone app. In summary, the proposed Au/Cu/Ti3C2 NSs-based method provided a novel and more comprehensive application for environmental monitoring. [ABSTRACT FROM AUTHOR]

In this paper, the design of a self-developed EMP simulator with a 5 m height and an inverted conducting mono-cone antenna with a cone half-angle of 32° is introduced. The experimental region of the simulator is a circular area of 25 m in diameter around the cone vertex. Two feeding modes, feed-in over the ground and feed-in under the ground, are realized by two different high-voltage pulse sources. It can be concluded through radiation field testing that the radiation field waveform generated by the simulator has a rise time of 2–3 ns and a half-width of about 25 ns, meeting the specifications of the EMP experimental waveform in the IEC61000-2-9 standard. Meanwhile, the differences between the engineering implementation of the simulator and its ideal structure during the design process can lead to some distortion issues in the antenna radiation characteristics and the electromagnetic radiation field it generates. The radiation field waveform and the distribution of the EMP field generated by the simulator under different feeding methods, antenna wire quantities, antenna end processing methods, and different antenna resistive loading were studied, and the changes in the radiation field waveform and field distribution with different angles and distances of the monitoring point were analyzed. Based on the measurement results, the radiation characteristics of the antenna and the factors that affect the waveform of the field were studied and analyzed. Through the aforementioned work, a comprehensive understanding of the performance, radiation characteristics, and engineering factors affecting the electromagnetic environment generated by the simulator has been obtained. On this basis, the parameters of the antenna wire quantity, antenna end processing method, and test point position of the designed simulator were reconfirmed and optimized. In summary, this work has important reference significance for mastering the development technology of such simulators, understanding their antenna radiation characteristics, and conducting EMP-related assessments and effect experiments in the future. [ABSTRACT FROM AUTHOR]

The interactions between extra‐embryonic tissues and embryonic tissues are crucial to ensure proper early embryo development. However, the understanding of the crosstalk between the embryonic tissues and extra‐embryonic tissues is lacking, mainly due to ethical restrictions, difficulties in obtaining natural human embryos, and lack of appropriate in vitro models. Here by aggregating human embryonic stem cells (hESCs) with human trophoblast stem cells (hTSCs), we revealed the hESCs robustly self‐organized into a unique asymmetric structure which the primitive streak (PS) like cells exclusively distributed at the distal end to the TS‐compartment, and morphologically flattened cells, presumed to be the extra‐embryonic mesoderm cells (EXMC) like cells, were induced at the proximal end to hTSCs. Our study revealed two potential roles of extra‐embryonic trophectoderm in regulating the proper PS formation during gastrulation and EXMCs induction from the human epiblast. [ABSTRACT FROM AUTHOR]

Purpose: The angiotensin converting enzyme-2 (ACE2)—entry receptor of SARS-CoV-2—and its homologue, the angiotensin-converting enzyme (ACE), play a pivotal role in maintaining cardiovascular homeostasis. Potential changes in ACE2 expression levels and dynamics after SARS-CoV-2 infection have been barely investigated. The aim of this study was to develop an ACE2-targeting imaging agent as a noninvasive imaging tool to determine ACE2 regulation. Methods: DOTA-DX600, NODAGA-DX600 and HBED-CC-DX600 were obtained through custom synthesis and labeled with gallium-67 (T1/2 = 3.26 d) as a surrogate radioisotope for gallium-68 (T1/2 = 68 min). ACE2- and ACE-transfected HEK cells were used for the in vitro evaluation of these radiopeptides. The in vivo tissue distribution profiles of the radiopeptides were assessed in HEK-ACE2 and HEK-ACE xenografted mice and imaging studies were performed using SPECT/CT. Results: The highest molar activity was obtained for [67Ga]Ga-HBED-CC-DX600 (60 MBq/nmol), whereas the labeling efficiency of the other peptides was considerably lower (20 MBq/nmol). The radiopeptides were stable over 24 h in saline (> 99% intact peptide). All radiopeptides showed uptake in HEK-ACE2 cells (36–43%) with moderate ACE2-binding affinity (KD value: 83–113 nM), but no uptake in HEK-ACE cells (< 0.1%) was observed. Accumulation of the radiopeptides was observed in HEK-ACE2 xenografts (11–16% IA/g) at 3 h after injection, but only background signals were seen in HEK-ACE xenografts (< 0.5% IA/g). Renal retention was still high 3 h after injection of [67Ga]Ga-DOTA-DX600 and [67Ga]Ga-NODAGA-DX600 (~ 24% IA/g), but much lower for [67Ga]Ga-HBED-CC-DX600 (7.2 ± 2.2% IA/g). SPECT/CT imaging studies confirmed the most favorable target-to-nontarget ratio for [67Ga]Ga-HBED-CC-DX600. Conclusions: This study demonstrated ACE2 selectivity for all radiopeptides. [67Ga]Ga-HBED-CC-DX600 was revealed as the most promising candidate due to its favorable tissue distribution profile. Importantly, the HBED-CC chelator enabled 67Ga-labeling at high molar activity, which would be essential to obtain images with high signal-to-background contrast to detect (patho)physiological ACE2 expression levels in patients. [ABSTRACT FROM AUTHOR]

Highlights: Large-area production of self-standing graphene nanofilm (~ 20 cm) through a clean 'substrate replacement' strategy. Realizing highly crystalline graphene nanofilms without micro-gasbags by introducing polymers. The graphene nanofilms demonstrate a solid light–matter interaction (photoelectric conversion in the mid-infrared and electromagnetic interference (EMI) shielding in X-band) with performance beyond state-of-the-art graphene/silicon diodes and EMI materials. Bulk graphene nanofilms feature fast electronic and phonon transport in combination with strong light–matter interaction and thus have great potential for versatile applications, spanning from photonic, electronic, and optoelectronic devices to charge-stripping and electromagnetic shielding, etc. However, large-area flexible close-stacked graphene nanofilms with a wide thickness range have yet to be reported. Here, we report a polyacrylonitrile-assisted 'substrate replacement' strategy to fabricate large-area free-standing graphene oxide/polyacrylonitrile nanofilms (lateral size ~ 20 cm). Linear polyacrylonitrile chains-derived nanochannels promote the escape of gases and enable macro-assembled graphene nanofilms (nMAGs) of 50–600 nm thickness following heat treatment at 3,000 °C. The uniform nMAGs exhibit 802–1,540 cm2 V−1 s−1 carrier mobility, 4.3–4.7 ps carrier lifetime, and > 1,581 W m−1 K−1 thermal conductivity (nMAG-assembled 10 µm-thick films, mMAGs). nMAGs are highly flexible and show no structure damage even after 1.0 × 105 cycles of folding–unfolding. Furthermore, nMAGs broaden the detection region of graphene/silicon heterojunction from near-infrared to mid-infrared and demonstrate higher absolute electromagnetic interference (EMI) shielding effectiveness than state-of-the-art EMI materials of the same thickness. These results are expected to lead to the broad applications of such bulk nanofilms, especially as micro/nanoelectronic and optoelectronic platforms. [ABSTRACT FROM AUTHOR]