In the field of maneuvering target tracking, the combined observations of azimuth and Doppler may cause weak observation or non-observation in the application of traditional target-tracking ...algorithms. Additionally, traditional target tracking algorithms require pre-defined multiple mathematical models to accurately capture the complex motion states of targets, while model mismatch and unavoidable measurement noise lead to significant errors in target state prediction. To address those above challenges, in recent years, the target tracking algorithms based on neural networks, such as recurrent neural networks (RNNs), long short-term memory (LSTM) networks, and transformer architectures, have been widely used for their unique advantages to achieve accurate predictions. To better model the nonlinear relationship between the observation time series and the target state time series, as well as the contextual relationship among time series points, we present a deep learning algorithm called recursive downsample-convolve-interact neural network (RDCINN) based on convolutional neural network (CNN) that downsamples time series into subsequences and extracts multi-resolution features to enable the modeling of complex relationships between time series, which overcomes the shortcomings of traditional target tracking algorithms in using observation information inefficiently due to weak observation or non-observation. The experimental results show that our algorithm outperforms other existing algorithms in the scenario of strong maneuvering target tracking with the combined observations of azimuth and Doppler.
Ag nanoclusters (AgNCs) have gained widespread applications in recent years due to their excellent antimicrobial efficacy and distinctive molecule-like characteristics. However, concerns about their ...potential effects on environmental and human health have been raised. Despite the fact that abundant research has been carried out to examine the possible ecotoxicology of AgNCs in a variety of living organisms, these studies have mostly concentrated on the toxicology of individual organisms and only a few have attempted to look into the impact of AgNCs across the aquatic food chain. This work evaluated the transcriptome level genotoxicity of AgNCs and their degraded Ag ions in two model species food chains: the aquatic green algae Scenedesmus obliquus and the invertebrate Daphnia magna. Daphnia magna’s digestive system and glycerophospholipid metabolism were hindered after feeding on Ag-containing algae as a result of down-regulation of the crucial gene PLA2G(SPLA2) that codes for secretory phospholipase A2. Our research also showed that the genotoxicity of AgNCs to Daphnia magna was mediated by a synergic interaction between the particulate form of AgNCs and their degraded Ag ions. The current work offers a fresh viewpoint on the mechanisms underlying AgNCs’ harmful effects and the possible ecological concern that metal-based nanoparticles provide to aquatic life.
Electrochemical CO2 reduction reaction (CO2RR) is an efficient way in the utilization of CO2. In this work, single transition-metal (TM) atom (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) anchored on ...two-dimensional (2D) Ti2CN2 are designed for CO2RR using density-functional-theory (DFT) calculation. We show that Ti2CN2 serves as an excellent substrate to support single atom catalysts (SACs), compared to Ti2CO2 and Ti2CF2. We find that the Sc, Ti and V supported on Ti2CN2 show high catalytic activities to produce CO with a low overpotential of 0.37, 0.27, and 0.23 eV, respectively. Differently, the Mn and Fe on Ti2CN2 are catalytically active for the production of HCOOH with a low overpotential of 0.32 and 0.43 eV, respectively. We further show that the negatively charged TM-Ti2CN2 can capture and activate CO2 more effectively, and the catalytic activity and selectivity can be significantly tuned by injecting extra electrons.
Display omitted
•Ti2CN2 serves as an excellent substrate to support single atom catalysts (SACs).•SACs supported on Ti2CN2 show high catalytic activities for CO2RR.•The negatively charged TM-Ti2CN2 can capture and activate CO2 more effectively.•The negative charging can tune the product and efficiency of TM-Ti2CN2 in CO2RR.
We compute the effective good divisibility of a rational homogeneous variety, extending an earlier result for complex Grassmannians by Naldi and Occhetta. Non-existence of nonconstant morphisms to ...rational homogeneous varieties of classical Lie type are obtained as applications.
Pancreatic intraepithelial neoplasia (PanIN) is a precursor of pancreatic ductal adenocarcinoma (PDAC), which commonly occurs in the general populations with aging. Although most PanIN lesions ...(PanINs) harbor oncogenic KRAS mutations that initiate pancreatic tumorigenesis; PanINs rarely progress to PDAC. Critical factors that promote this progression, especially targetable ones, remain poorly defined. We show that peroxisome proliferator-activated receptor-delta (PPARδ), a lipid nuclear receptor, is upregulated in PanINs in humans and mice. Furthermore, PPARδ ligand activation by a high-fat diet or GW501516 (a highly selective, synthetic PPARδ ligand) in mutant KRAS
(KRAS
) pancreatic epithelial cells strongly accelerates PanIN progression to PDAC. This PPARδ activation induces KRAS
pancreatic epithelial cells to secrete CCL2, which recruits immunosuppressive macrophages and myeloid-derived suppressor cells into pancreas via the CCL2/CCR2 axis to orchestrate an immunosuppressive tumor microenvironment and subsequently drive PanIN progression to PDAC. Our data identify PPARδ signaling as a potential molecular target to prevent PDAC development in subjects harboring PanINs.
Abstract
Oxygen evolution reaction catalysts capable of working efficiently in acidic media are highly demanded for the commercialization of proton exchange membrane water electrolysis. Herein, we ...report a Zn-doped RuO
2
nanowire array electrocatalyst with outstanding catalytic performance for the oxygen evolution reaction under acidic conditions. Overpotentials as low as 173, 304, and 373 mV are achieved at 10, 500, and 1000 mA cm
−2
, respectively, with robust stability reaching to 1000 h at 10 mA cm
−2
. Experimental and theoretical investigations establish a clear synergistic effect of Zn dopants and oxygen vacancies on regulating the binding configurations of oxygenated adsorbates on the active centers, which then enables an alternative Ru−Zn dual-site oxide path of the reaction. Due to the change of reaction pathways, the energy barrier of rate-determining step is reduced, and the over-oxidation of Ru active sites is alleviated. As a result, the catalytic activity and stability are significantly enhanced.
The development of inexpensive, highly active, and stable non-precious metal catalysts is the key to efficient H2 production by the electrolysis of water. Based on initial theoretical predictions, we ...report the design and synthesis of N-doped, defect-containing, carbon-dots (CDs)-loaded molybdenum phosphide (MoP/CDs) nanoparticles using CDs with different N contents. This optimized composite material performed outstandingly in the hydrogen evolution reaction (HER), with an overpotential of 70 mV at a current density of 10 mA cm−2 with a 1.0 M KOH electrolyte. N doping changed the electronic arrangement around the reaction site, promoting the adsorption of HER intermediates. Increasing the N content further activated the adjacent C atoms to detach due to the more negative C vacancy formation energies resulting in a defect site with lost atoms and changed bond lengths. The introduction of defects increases the number of dangling bonds adjacent to reaction sites and reduces site coordination numbers, changing their electrocatalytic activity. Results show that N-doped and defect-containing MoP/CDs nanoparticles have excellent H2 production performance during the electrolysis of alkaline solution. These findings open a new area of application of heteroatom-doped CDs and provide new ideas for the design of efficient carbon-semiconductor composite HER catalysts.
Display omitted
•CDs with different N contents were successfully synthesized.•Under the guidance of the theoretical calculation, three N-content CDs-loaded MoP nanocomposites were presented.•The critical role of N doping content in electrocatalytic materials was revealed.•The synthetic catalyst has an excellent catalytic performance in the alkaline medium.
The coexistence of ferroelectricity and magnetism in two-dimensional (2D) multiferroic materials with the thickness of few atomic layers offers a tantalizing potential for high-density multistate ...data storage but has been rarely verified in experiments. Herein, we propose a realistic 2D multiferroic material, VOCl2 monolayer, which is mechanically strippable from the bulk material. It has a large intrinsic in-plane spontaneous electric polarization of 312 pC m−1 and stable antiferromagnetism with the Néel temperature of 177 K. The off-center displacement of V ions that contributes to the ferroelectricity can be ascribed to the pseudo Jahn–Teller distortion. The energy barrier (0.18 eV) between two ferroelectric states with opposite electronic polarization renders the thermodynamic stability of the ferroelectricity and the switchability of the electric polarizations. The interplay between electric polarization and magnetism would lead to tunable ferroelectricity. Our findings are expected to offer a realistic platform for the study of 2D multiferroic materials as well as their applications in miniaturized memory devices.
Photocatalytic CO2 conversion into reproducible chemical fuels (e.g., CO, CH3OH, or CH4) provides a promising scheme to solve the increasing environmental problems and energy demands simultaneously. ...However, the efficiency is severely restricted by the high overpotential of the CO2 reduction reaction (CO2RR) and rapid recombination of photoexcited carriers. Here, we propose that a novel type-II photocatalytic mechanism based on two-dimensional (2D) ferroelectric multilayers would be ideal for addressing these issues. Using density-functional theory and nonadiabatic molecular dynamics calculations, we find that the ferroelectric CuInP2S6 bilayers exhibit a staggered band structure induced by the vertical intrinsic electric fields. Different from the traditional type-II band alignment, the unique structure of the CuInP2S6 bilayer not only effectively suppresses the recombination of photogenerated electron–hole (e–h) pairs but also produces a sufficient photovoltage to drive the CO2RR. The predicted recombination time of photogenerated e–h pairs, 1.03 ns, is much longer than the transferring times of photoinduced electrons and holes, 5.45 and 0.27 ps, respectively. Moreover, the overpotential of the CO2RR will decrease by substituting an S atom with a Cu atom, making the redox reaction proceed spontaneously under solar radiation. The solar-to-fuel efficiency with an upper limit of 8.40% is achieved in the CuInP2S6 bilayer and can be further improved to 32.57% for the CuInP2S6 five-layer. Our results indicate that this novel type-II photocatalytic mechanism would be a promising way to achieve highly efficient photocatalytic CO2 conversion based on the 2D ferroelectric multilayers.
Loss of the histone H3.3‐specific chaperone component ATRX or its partner DAXX frequently occurs in human cancers that employ alternative lengthening of telomeres (ALT) for chromosomal end ...protection, yet the underlying mechanism remains unclear. Here, we report that ATRX/DAXX does not serve as an immediate repressive switch for ALT. Instead, ATRX or DAXX depletion gradually induces telomere DNA replication dysfunction that activates not only homology‐directed DNA repair responses but also cell cycle checkpoint control. Mechanistically, we demonstrate that this process is contingent on ATRX/DAXX histone chaperone function, independently of telomere length. Combined ATAC‐seq and telomere chromatin immunoprecipitation studies reveal that ATRX loss provokes progressive telomere decondensation that culminates in the inception of persistent telomere replication dysfunction. We further show that endogenous telomerase activity cannot overcome telomere dysfunction induced by ATRX loss, leaving telomere repair‐based ALT as the only viable mechanism for telomere maintenance during immortalization. Together, these findings implicate ALT activation as an adaptive response to ATRX/DAXX loss‐induced telomere replication dysfunction.
Synopsis
Alternative lengthening of telomeres (ALT) in human cancers is frequently associated with loss of the histone H3.3 chaperone ATRX or its cofactor DAXX. This study shows that ATRX/DAXX do not function as immediate repressor of ALT, but that ALT is rather an an adaptive response to ATRX depletion‐induced telomere replication dysfunction.
ATRX loss induces telomere replication dysfunction irrespective of endogenous telomerase activity.
ATRX‐DAXX histone H3.3 chaperone activity is required for telomere maintenance.
ATRX depletion progressively induces chromatin de‐compaction at telomeres.
ATRX loss dictates the telomere maintenance program during ATRX mutant cell immortalization.
Telomere maintenance by ALT emerges as an adaptive response to progressive telomere decompaction in the absence of the H3.3 chaperone ATRX/DAXX, rather than being immediately de‐repressed upon ATRX depletion.
PDF