Enhancing Effect of Fullerene Guest and Counterion on the Structural Stability and Electrical Conductivity of Octahedral Metallo-Supramolecular Cages.

Metallo-supramolecular cages have garnered tremendous attention for their diverse yet molecular-level precision structures. However, physical properties of these supramolecular ensembles, which are of potential significance in molecular electronics, remain largely unexplored. We herein constructed a series of octahedral metallo-cages and cage-fullerene complexes with notably enhanced structural stability. As such, we could systematically evaluate the electrical conductivity of these ensembles at both single-molecule level and aggregated bulk state (as well-defined films). Our findings reveal that counteranions and fullerene guests play a pivotal role in determining the electrical conductivity of aggregated state, while such effects are less significant for single-molecule conductance. Both counteranions and fullerenes effectively tune the electronic structures and packing density of metallo-supramolecular assemblies, and facilitate efficient charge transfer between the cage hosts and fullerenes, resulting in a notable one order of magnitude increase in electrical conductivity of the aggregated state.

Unveiling the domino effect: a nine-year follow-up on pentalogy of central nervous system induced by a large unruptured cerebral arteriovenous malformation: a case report and literature review.

Background: The disruption of intracranial fluid dynamics due to large unruptured cerebral arteriovenous malformation (AVM) commonly triggers a domino effect within the central nervous system. This phenomenon is frequently overlooked in prior clinic and may lead to catastrophic misdiagnoses. Our team has documented the world's first case of so-called AVM Pentalogy (AVMP) induced by a AVM. Clinical presentation and result: A 30-year-old female was first seen 9 years ago with an occasional fainting, at which time a huge unruptured AVM was discovered. Subsequently, due to progressive symptoms, she sought consultations from several prestigious neurosurgical departments in China, where all consulting neurosurgeons opted for conservation treatment due to perceived surgical risks. During the follow-up period, the patient gradually presented with hydrocephalus, empty sella, secondary Chiari malformation, syringomyelia, and scoliosis (we called as AVMP). When treated in our department, she already displayed numerous symptoms, including severe intracranial hypertension. Our team deduced that the hydrocephalus was the primary driver of her AVMP symptoms, representing the most favorable risk profile for intervention. As expected, a ventriculoperitoneal shunt successfully mitigated all symptoms of AVMP at 21-months post-surgical review. Conclusion: During the monitoring of unruptured AVM, it is crucial to remain vigilant for the development or progression of AVMP. When any component of AVMP is identified, thorough etiological studies and analysis of cascade reactions are imperative to avert misdiagnosis. When direct AVM intervention is not viable, strategically addressing hydrocephalus as part of the AVMP may serve as the critical therapeutic focus.

Roentgenoscopy of laser-induced projectile impact testing.

Laser-induced projectile impact testing (LIPIT) based on synchrotron imaging is proposed and validated. This emerging high-velocity, high-strain microscale dynamic loading technique offers a unique perspective on the strain and energy dissipation behavior of materials subjected to high-speed microscale single-particle impacts. When combined with synchrotron radiation imaging techniques, LIPIT allows for in situ observation of particle infiltration. Two validation experiments were carried out, demonstrating the potential of LIPIT in the roentgenoscopy of the dynamic properties of various materials. With a spatial resolution of 10 µm and a temporal resolution of 33.4 µs, the system was successfully realized at the Beijing Synchrotron Radiation Facility 3W1 beamline. This innovative approach opens up new avenues for studying the dynamic properties of materials in situ.

Mango wiggler as a novel insertion device providing a large and symmetrical imaging field of view.

A novel insertion device is introduced, designated as the Mango wiggler, designed for synchrotron radiation (SR) imaging that provides a large field of view. This innovative device is constructed from two orthogonal planar wigglers with a small difference in their period lengths, eliciting the phase difference of the magnetic fields to incrementally transitions from 0 to π/2. Such a configuration enlarges the vertical divergence of the light source, as with the horizontal divergence. The appellation `Mango wiggler' derives from the distinctive mango-shaped contour of its radiation field. A comprehensive suite of theoretical analyses and simulations has been executed to elucidate the radiation properties of the Mango wiggler, employing SPECTRA and Mathematica as calculation tools. In conjunction with the ongoing construction of the High Energy Photon Source in Beijing a practical Mango wiggler device has been fabricated for utilization in SR imaging applications. Theoretical analyses were applied to this particular Mango wiggler to yield several theoretical conclusions, and several simulations were performed according to the measured magnetic field results.

Single-cell transcriptomics across 2,534 microbial species reveals functional heterogeneity in the rumen microbiome.

Deciphering the activity of individual microbes within complex communities and environments remains a challenge. Here we describe the development of microbiome single-cell transcriptomics using droplet-based single-cell RNA sequencing and pangenome-based computational analysis to characterize the functional heterogeneity of the rumen microbiome. We generated a microbial genome database (the Bovine Gastro Microbial Genome Map) as a functional reference map for the construction of a single-cell transcriptomic atlas of the rumen microbiome. The atlas includes 174,531 microbial cells and 2,534 species, of which 172 are core active species grouped into 12 functional clusters. We detected single-cell-level functional roles, including a key role for Basfia succiniciproducens in the carbohydrate metabolic niche of the rumen microbiome. Furthermore, we explored functional heterogeneity and reveal metabolic niche trajectories driven by biofilm formation pathway genes within B. succiniciproducens. Our results provide a resource for studying the rumen microbiome and illustrate the diverse functions of individual microbial cells that drive their ecological niche stability or adaptation within the ecosystem.

Adaptive Processing Enabled by Sodium Alginate Based Complementary Memristor for Neuromorphic Sensory System.

Adaptive processing allows sensory systems to autonomically adjust their sensitivity with exposure to a constant sensory stimulus and thus organisms to adapt to environmental variations. Bioinspired electronics with adaptive functions are highly desirable for the development of neuromorphic sensory systems (NSSs). Herein, the functions of desensitization and sensitivity changing with background intensity (i.e., Weber's law), as two fundamental cues of sensory adaptation, are biorealistically demonstrated in an Ag nanowire (NW)-embedded sodium alginate (SA) based complementary memristor. In particular, Weber's law is experimentally emulated in a single complementary memristor. Furthermore, three types of adaptive NSS unit are constructed to realize a multiple perceptual capability that processes the stimuli of illuminance, temperature, and pressure signals. Taking neuromorphic vision as an example, scotopic and photopic adaptation functions are well reproduced for image enhancement against dark and bright backgrounds. Importantly, an NSS system with multisensory integration function is demonstrated by combining light and pressure spikes, where the accuracy of pattern recognition is obviously enhanced relative to that of an individual sense. This work offers a new strategy for developing neuromorphic electronics with adaptive functions and paves the way toward developing a highly efficient NSS.

Articulated Motion-Aware NeRF for 3D Dynamic Appearance and Geometry Reconstruction by Implicit Motion States.

We propose a self-supervised approach for 3D dynamic reconstruction of articulated motions based on Generative Adversarial Networks and Neural Radiance Fields. Our method reconstructs articulated objects and recover their continuous motions and attributes from an unordered, discontinuous image set. Notably, we treat motion states as time-independent, recognizing that articulated objects can exhibit identical motions at different times. The key insight of our approach utilizes generative adversarial networks to create a continuous implicit motion state space. Initially, we employ a motion network extracts discrete motion states from images as anchors. These anchors are then expanded across the latent space using generative adversarial networks. Subsequently, motion state latent codes are input into motion-aware neural radiance fields for dynamic appearance and geometry reconstruction. To deduce motion attributes from the continuously generated motions, we adopt a cluster-based strategy. We thoroughly evaluate and validate our method on both synthesized and real data, demonstrating superior fidelity in appearances, geometries, and motion attributes of articulated objects compared to state-of-the-art methods.

Knowledge Graphs and Pretrained Language Models Enhanced Representation Learning for Conversational Recommender Systems.

Conversational recommender systems (CRSs) utilize natural language interactions and dialog history to infer user preferences and provide accurate recommendations. Due to the limited conversation context and background knowledge, existing CRSs rely on external sources such as knowledge graphs (KGs) to enrich the context and model entities based on their interrelations. However, these methods ignore the rich intrinsic information within entities. To address this, we introduce the knowledge-enhanced entity representation learning (KERL) framework, which leverages both the KG and a pretrained language model (PLM) to improve the semantic understanding of entities for CRS. In our KERL framework, entity textual descriptions are encoded via a PLM, while a KG helps reinforce the representation of these entities. We also employ positional encoding to effectively capture the temporal information of entities in a conversation. The enhanced entity representation is then used to develop a recommender component that fuses both entity and contextual representations for more informed recommendations, as well as a dialog component that generates informative entity-related information in the response text. A high-quality KG with aligned entity descriptions is constructed to facilitate this study, namely, the Wiki Movie Knowledge Graph (WikiMKG). The experimental results show that KERL achieves state-of-the-art results in both recommendation and response generation tasks. Our code is publicly available at the link: https://github.com/icedpanda/KERL.

Bacterial imaging in tumour diagnosis.

Some bacteria, such as Escherichia coli (E. coli) and Salmonella typhimurium (S. typhimurium), have an inherent ability to locate solid tumours, making them a versatile platform that can be combined with other tools to improve the tumour diagnosis and treatment. In anti-cancer therapy, bacteria function by carrying drugs directly or expressing exogenous therapeutic genes. The application of bacterial imaging in tumour diagnosis, a novel and promising research area, can indeed provide dynamic and real-time monitoring in both pre-treatment assessment and post-treatment detection. Different imaging techniques, including optical technology, acoustic imaging, magnetic resonance imaging (MRI) and nuclear medicine imaging, allow us to observe and track tumour-associated bacteria. Optical imaging, including bioluminescence and fluorescence, provides high-sensitivity and high-resolution imaging. Acoustic imaging is a real-time and non-invasive imaging technique with good penetration depth and spatial resolution. MRI provides high spatial resolution and radiation-free imaging. Nuclear medicine imaging, including positron emission tomography (PET) and single photon emission computed tomography (SPECT) can provide information on the distribution and dynamics of bacterial population. Moreover, strategies of synthetic biology modification and nanomaterial engineering modification can improve the viability and localization ability of bacteria while maintaining their autonomy and vitality, thus aiding the visualization of gut bacteria. However, there are some challenges, such as the relatively low bacterial abundance and heterogeneously distribution within the tumour, the high dimensionality of spatial datasets and the limitations of imaging labeling tools. In summary, with the continuous development of imaging technology and nanotechnology, it is expected to further make in-depth study on tumour-associated bacteria and develop new bacterial imaging methods for tumour diagnosis.

Mn(II)-Based Metal Halide with Near-Unity Quantum Yield for White LEDs and High-Resolution X-ray Imaging.

Metal halides have drawn great interest as luminescent materials and scintillators due to their outstanding optical properties. Exploring new types of phosphors with easy production processes, excellent photophysical properties, high light yields, and environmentally friendly compositions is crucial and quite challenging. Herein, a novel Mn(II)-based metal halide (4-BTP)2MnBr4 was produced using a facile solvent evaporation method, which exhibited a strong green emission peaking at 524 nm from the d-d transition of tetrahedral-coordinated Mn2+ ion and a near-unity quantum yield. The prepared white light-emitting diode device has a wide color gamut of 100.7% NTSC with CIE chromaticity coordinates of (0.32, 0.32). In addition, (4-BTP)2MnBr4 demonstrates excellent characteristics in X-ray scintillation, including a high light yield of 98 000 photons/MeV, a sensitive detection limit of 37.4 nGy/s, excellent resistance to radiation damage, and successful demonstration of X-ray imaging with high resolution at 21.3 lp/mm, revealing the potential for application in diagnostic X-ray medical imaging and industry radiation detection.

Unveiling the role of CaMKII in retinal degeneration: from biological mechanism to therapeutic strategies.

Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a family of broad substrate specificity serine (Ser)/threonine (Thr) protein kinases that play a crucial role in the Ca2+-dependent signaling pathways. Its significance as an intracellular Ca2+ sensor has garnered abundant research interest in the domain of neurodegeneration. Accumulating evidences suggest that CaMKII is implicated in the pathology of degenerative retinopathies such as diabetic retinopathy (DR), age-related macular degeneration (AMD), retinitis pigmentosa (RP) and glaucoma optic neuropathy. CaMKII can induce the aberrant proliferation of retinal blood vessels, influence the synaptic signaling, and exert dual effects on the survival of retinal ganglion cells and pigment epithelial cells. Researchers have put forth multiple therapeutic agents, encompassing small molecules, peptides, and nucleotides that possess the capability to modulate CaMKII activity. Due to its broad range isoforms and splice variants therapeutic strategies seek to inhibit specifically the CaMKII are confronted with considerable challenges. Therefore, it becomes crucial to discern the detrimental and advantageous aspects of CaMKII, thereby facilitating the development of efficacious treatment. In this review, we summarize recent research findings on the cellular and molecular biology of CaMKII, with special emphasis on its metabolic and regulatory mechanisms. We delve into the involvement of CaMKII in the retinal signal transduction pathways and discuss the correlation between CaMKII and calcium overload. Furthermore, we elaborate the therapeutic trials targeting CaMKII, and introduce recent developments in the zone of CaMKII inhibitors. These findings would enrich our knowledge of CaMKII, and shed light on the development of a therapeutic target for degenerative retinopathy.

Identification of the succinate-CoA ligase protein gene family reveals that TaSUCL1-1 positively regulate cadmium resistance in wheat.

The Succinate-CoA ligase (SUCL1) gene family is involved in energy metabolism, phytohormone signaling, and plant growth, development, and tolerance to stress. This is the first study to analyze the SUCL1 gene family in wheat (Triticum aestivum). 17 TaSUCL1 genes were identified in the complete genome sequence and classified into five subfamilies based on related genes found in three other species. The 17 TaSUCL1 genes were unevenly distributed across 11 chromosomes, and the collinearity of these genes was further investigated. Through using real-time qPCR (RT-qPCR) analysis, we identified the expression patterns of the TaSUCL1 genes under various tissues and different heavy metal stress conditions. The functions of selected TaSUCL1-1 gene were investigated by RNA interference (RNAi). This study provided a comprehensive analysis of the TaSUCL1 gene family. Within the TaSUCL1 genes, the exon-intron structure and motif composition exhibited significant similarity among members of the same evolutionary branch. Homology analysis and phylogenetic comparison of the SUCL1 genes in different plants offered valuable insights for studying the evolutionary characteristics of the SUCL1 genes. The expression levels of the TaSUCL1 genes in different tissues and under various metal stress conditions reveal its important role in plant growth and development. Gene function analysis demonstrated that TaSUCL1-1 silenced wheat plants exhibited a decrease in the total cadmium (Cd) concentrations and gene expression levels compared to the wild type (WT). Additionally, TaSUCL1-1 belonging to class c physically interacts with the ß-amylase protein TaBMY1 as verified by yeast two-hybridization. This research provides a useful resource for further study of the function and molecular genetic mechanism of the SUCL1 gene family members.

The significance of precisely regulating heme oxygenase-1 expression: Another avenue for treating age-related ocular disease?

Aging entails the deterioration of the body's organs, including overall damages at both the genetic and cellular levels. The prevalence of age-related ocular disease such as macular degeneration, dry eye diseases, glaucoma and cataracts is increasing as the world's population ages, imposing a considerable economic burden on individuals and society. The development of age-related ocular disease is predominantly triggered by oxidative stress and chronic inflammatory reaction. Heme oxygenase-1 (HO-1) is a crucial antioxidant that mediates the degradative process of endogenous iron protoporphyrin heme. It catalyzes the rate-limiting step of the heme degradation reaction, and releases the metabolites such as carbon monoxide (CO), ferrous, and biliverdin (BV). The potent scavenging activity of these metabolites can help to defend against peroxides, peroxynitrite, hydroxyl, and superoxide radicals. Other than directly decomposing endogenous oxidizing substances (hemoglobin), HO-1 is also a critical regulator of inflammatory cells and tissue damage, exerting its anti-inflammation activity through regulating complex inflammatory networks. Therefore, promoting HO-1 expression may act as a promising therapeutic strategy for the age-related ocular disease. However, emerging evidences suggest that the overexpression of HO-1 significantly contributes to ferroptosis due to its dual nature. Surplus HO-1 leads to excessive Fe2+ and reactive oxygen species, thereby causing lipid peroxidation and ferroptosis. In this review, we elucidate the role of HO-1 in countering age-related disease, and summarize recent pharmacological trials that targeting HO-1 for disease management. Further refinements of the knowledge would position HO-1 as a novel therapeutic target for age-related ocular disease.

Human immunodeficiency virus-associated dementia complex with positive 14-3-3 protein in cerebrospinal fluid: A case report.

BACKGROUND: Human immunodeficiency virus (HIV)-associated dementia (HAD) is a subcortical form of dementia characterized by memory deficits and psychomotor slowing. However, HAD often presents with symptoms similar to those of Creutzfeldt-Jakob disease (CJD), particularly in patients with acquired immune deficiency syndrome (AIDS). CASE SUMMARY: We report the case of a 54-year-old male who exhibited cognitive dysfunction and secondary behavioral changes following HIV infection and suspected prion exposure. The patient was diagnosed with HIV during hospitalization and his cerebrospinal fluid tested positive for 14-3-3 proteins. His electroencephalogram showed a borderline-abnormal periodic triphasic wave pattern. Contrast-enhanced magnetic resonance imaging revealed moderate encephalatrophy and demyelination. Initially, symptomatic treatment and administration of amantadine were pursued for presumed CJD, but the patient's condition continued to deteriorate. By contrast, the patient's condition improved following anti-HIV therapy. This individual is also the only patient with this prognosis to have survived over 4 years. Thus, the diagnosis was revised to HAD. CONCLUSION: In the diagnostic process of rapidly progressive dementia, it is crucial to rule out as many potential causes as possible and to consider an autopsy to diminish diagnostic uncertainty. The 14-3-3 protein should not be regarded as the definitive marker for CJD. Comprehensive laboratory screening for infectious diseases is essential to enhance diagnostic precision, especially in AIDS patients with potential CJD. Ultimately, a trial of diagnostic treatment may be considered when additional testing is not feasible.

Thermocatalytic Hydrogen Production from Water at Boiling Condition.

Thermochemical water-splitting cycles are technically feasible for hydrogen production from water. However, the ultrahigh operation temperature and low efficiency seriously restrict their practical application. Herein, one-step and one-pot thermocatalytic water-splitting process is reported at water boiling condition catalyzed by single atomic Pt on defective In2O3. Water splitting into hydrogen is verified by D2O isotopic experiment, with an optimized hydrogen production rate of 36.4 mmol·h-1·g-1 as calculated on Pt active sites. It is revealed that three-centered Pt1In2 surrounding oxygen vacancy as catalytic ensembles promote the dissociation of the adsorbed water into H, which transfers to singlet atomic Pt sites for H2 production. Remaining OH groups on adjacent In sites from Pt1In2 ensembles undergoes O─O bonding, hyperoxide formation and diminishing via triethylamine oxidation, water re-adsorption for completing the catalytic cycle. Current work represents an isothermal and continuous thermocatalytic water splitting under mild condition, which can re-awaken the research interest to produce H2 from water using low-grade heat and competes with photocatalytic, electrolytic, and photoelectric reactions.

Research hotspots and trends in the relationship between sport and nutrition: A bibliometric analysis from 2013 to 2023.

This research aimed to summarize the research development and hot points in on the connection between sport and nutrition overall through bibliometric analysis. We collected the publications in the last 10 years (2013-2023) related to between sport and nutrition in the Web of Science database, and applied Citespace to assess the knowledge mapping. The results showed as follows that the number of manuscripts about sport and nutrition totaled 10,016, with a faster increase after 2019. The country, institution, and author with the most publications are the USA, University of California System, Burke, Louise M. In addition, the most co-cited reference is Journal of the Academy of Nutrition and Dietetics (2016) (199). Based on a 10-year bibliometric investigation, we know the USA, the University of California System has become one of this discipline's major research forces. Research on sport and nutrition benefits from the best partnerships between industrialized nations and prominent universities.

Enabling robust blue circularly polarized organic afterglow through self-confining isolated chiral chromophore.

Creating circularly polarized organic afterglow system with elevated triplet energy levels, suppressed non-radiative transitions, and effective chirality, which are three critical prerequisites for achieving blue circularly polarized afterglow, has posed a formidable challenge. Herein, a straightforward approach is unveiled to attain blue circularly polarized afterglow materials by covalently self-confining isolated chiral chromophore within polymer matrix. The formation of robust hydrogen bonds within the polymer matrix confers a distinctly isolated and stabilized molecular state of chiral chromophores, endowing a blue emission band at 414 nm, lifetime of 3.0 s, and luminescent dissymmetry factor of ~ 10-2. Utilizing the synergistic afterglow and chirality energy transfer, full-color circularly polarized afterglow systems are endowed by doping colorful fluorescent molecules into designed blue polymers, empowering versatile applications. This work paves the way for the streamlined design of blue circularly polarized afterglow materials, expanding the horizons of circularly polarized afterglow materials into various domains.

PDT-YOLO: A Roadside Object-Detection Algorithm for Multiscale and Occluded Targets.

To tackle the challenges of weak sensing capacity for multi-scale objects, high missed detection rates for occluded targets, and difficulties for model deployment in detection tasks of intelligent roadside perception systems, the PDT-YOLO algorithm based on YOLOv7-tiny is proposed. Firstly, we introduce the intra-scale feature interaction module (AIFI) and reconstruct the feature pyramid structure to enhance the detection accuracy of multi-scale targets. Secondly, a lightweight convolution module (GSConv) is introduced to construct a multi-scale efficient layer aggregation network module (ETG), enhancing the network feature extraction ability while maintaining weight. Thirdly, multi-attention mechanisms are integrated to optimize the feature expression ability of occluded targets in complex scenarios, Finally, Wise-IoU with a dynamic non-monotonic focusing mechanism improves the accuracy and generalization ability of model sensing. Compared with YOLOv7-tiny, PDT-YOLO on the DAIR-V2X-C dataset improves mAP50 and mAP50:95 by 4.6% and 12.8%, with a parameter count of 6.1 million; on the IVODC dataset by 15.7% and 11.1%. We deployed the PDT-YOLO in an actual traffic environment based on a robot operating system (ROS), with a detection frame rate of 90 FPS, which can meet the needs of roadside object detection and edge deployment in complex traffic scenes.

Non-traumatic osteonecrosis of the femoral head induced by steroid and alcohol exposure is associated with intestinal flora alterations and metabolomic profiles.

OBJECTIVE: Osteonecrosis of the femoral head (ONFH) is a severe disease that primarily affects the middle-aged population, imposing a significant economic and social burden. Recent research has linked the progression of non-traumatic osteonecrosis of the femoral head (NONFH) to the composition of the gut microbiota. Steroids and alcohol are considered major contributing factors. However, the relationship between NONFH caused by two etiologies and the microbiota remains unclear. In this study, we examined the gut microbiota and fecal metabolic phenotypes of two groups of patients, and analyzed potential differences in the pathogenic mechanisms from both the microbial and metabolic perspectives. METHODS: Utilizing fecal samples from 68 NONFH patients (32 steroid-induced, 36 alcohol-induced), high-throughput 16 S rDNA sequencing and liquid chromatography with tandem mass spectrometry (LC-MS/MS) metabolomics analyses were conducted. Univariate and multivariate analyses were applied to the omics data, employing linear discriminant analysis effect size to identify potential biomarkers. Additionally, functional annotation of differential metabolites and associated pathways was performed using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Subsequently, Spearman correlation analysis was employed to assess the potential correlations between differential gut microbiota and metabolites. RESULTS: High-throughput 16 S rDNA sequencing revealed significant gut microbial differences. At the genus level, the alcohol group had higher Lactobacillus and Roseburia, while the steroid group had more Megasphaera and Akkermansia. LC-MS/MS metabolomic analysis indicates significant differences in fecal metabolites between steroid- and alcohol-induced ONFH patients. Alcohol-induced ONFH (AONFH) showed elevated levels of L-Lysine and Oxoglutaric acid, while steroid-induced ONFH(SONFH) had increased Gluconic acid and Phosphoric acid. KEGG annotation revealed 10 pathways with metabolite differences between AONFH and SONFH patients. Correlation analysis revealed the association between differential gut flora and differential metabolites. CONCLUSIONS: Our results suggest that hormones and alcohol can induce changes in the gut microbiota, leading to alterations in fecal metabolites. These changes, driven by different pathways, contribute to the progression of the disease. The study opens new research directions for understanding the pathogenic mechanisms of hormone- or alcohol-induced NONFH, suggesting that differentiated preventive and therapeutic approaches may be needed for NONFH caused by different triggers.

Evidence of Ferromagnetism and Ultrafast Dynamics of Demagnetization in an Epitaxial FeCl2 Monolayer.

The development of two-dimensional (2D) magnetism is driven not only by the interest of low-dimensional physics but also by potential applications in high-density miniaturized spintronic devices. However, 2D materials possessing a ferromagnetic order with a relatively high Curie temperature (Tc) are rare. In this paper, the evidence of ferromagnetism in monolayer FeCl2 on Au(111) surfaces, as well as the interlayer antiferromagnetic coupling of bilayer FeCl2, is characterized by using spin-polarized scanning tunneling microscopy. A Curie temperature (Tc) of ∼147 K is revealed for monolayer FeCl2, based on our static magneto-optical Kerr effect measurements. Furthermore, temperature-dependent magnetization dynamics is investigated by the time-resolved magneto-optical Kerr effect. A transition from one- to two-step demagnetization occurs as the lattice temperature approaches Tc, which supports the Elliott-Yafet spin relaxation mechanism. The findings contribute to a deeper understanding of the underlying mechanisms governing ultrafast magnetization in 2D ferromagnetic materials.