Declarations: management of a pulmonary arteriovenous fistulae by uniportal video-assisted thoracoscopic surgery: a case report

BACKGROUND

A pulmonary arteriovenous fistula (PAVF) is a rare condition that is associated with pulmonary arteriovenous malformation (PAVM). Few reports have described managing PAVMs using uniportal video-assisted thoracoscopic surgery (VATS).

CASE PRESENTATION

A 13-year-old child with PAVF in the left inferior pulmonary artery was treated by uniportal VATS with left lower lobectomy. After surgery, hemoptysis did not recur and there were no postoperative complications. Six months after the operation, postoperative review of computerized tomography showed no recrudescence of PAVF.

CONCLUSIONS

PAVF is a rare case that should be diagnosed and treated early. 3D- computerized tomography (CT) reconstruction is useful for diagnosis and preoperative assessment. The case shows that PAVF can be managed with uniportal VATS.

Calcite crystal orientation patterns in the bilayers of laminated shells of benthic rotaliid foraminifera

Shells of calcifying foraminifera play a major role in marine biogeochemical cycles; fossil shells form important archives for paleoenvironment reconstruction. Despite their importance in many Earth science disciplines, there is still little consensus on foraminiferal shell mineralization. Geochemical, biochemical, and physiological studies showed that foraminiferal shell formation might take place through various and diverse mineralization mechanisms. In this study, we contribute to benthic foraminiferal shell calcification through deciphering crystallite organization within the shells. We base our conclusions on results gained from electron backscattered diffraction (EBSD) measurements and describe microstructure/texture characteristics within the laminated shell walls of the benthic, symbiontic foraminifera: Ammonia tepida, Amphistegina lobifera, Amphistegina lessonii. We highlight crystallite assembly patterns obtained on differently oriented cuts and discuss crystallite sizes, morphologies, interlinkages, orientations, and co-orientation strengths. We show that: (i) crystals within benthic foraminiferal shells are mesocrystals, (ii) have dendritic-fractal morphologies and (iii) interdigitate strongly. Based on crystal size, we (iv) differentiate between the two layers that comprise the shells and demonstrate that (v) crystals in the septa have different assemblies relative to those in the shell walls. We highlight that (vi) at junctions of different shell elements the axis of crystal orientation jumps abruptly such that their assembly in EBSD maps has a bimodal distribution. We prove (vii) extensive twin-formation within foraminiferal calcite; we demonstrate (viii) the presence of two twin modes: 60°/[001] and 77°/~[6 -6 1] and visualize their distributions within the shells. In a broader perspective, we draw conclusions on processes that lead to the observed microstructure/texture patterns.

Comparative efficacy of respiratory personal protective equipment against viral respiratory infectious diseases in healthcare workers: a network meta-analysis

OBJECTIVE

With the epidemic of coronavirus disease 2019 (COVID-19), the healthcare workers (HCWs) require proper respiratory personal protective equipment (rPPE) against viral respiratory infectious diseases (VRIDs). It is necessary to evaluate which type of mask and manner of wearing is the best suitable rPPE for preventing the VRID.

STUDY DESIGN

A Bayesian network meta-analysis was performed to comprehensively analyze the protective efficacy of various rPPE.

METHODS

This network meta-analysis protocol was registered in an international prospective register of systematic reviews (CRD42020179489). Electronic databases were searched for cluster randomized control trials (RCTs) of comparing the effectiveness of rPPE and wearing manner in preventing HCWs from VRID. The primary outcome was the incidence of laboratory-confirmed viral respiratory infection reported as an odds ratio (OR) with the associated 95% credibility interval (CrI). The secondary outcome was the incidence of clinical respiratory illness (CRI) reported as an OR with the associated 95% CrI. Surface under the cumulative ranking curve analysis (SUCRA) provided a ranking of each rPPE according to the primary outcome and the secondary outcome as data supplement.

RESULTS

Six studies encompassing 12,265 HCWs were included. In terms of the incidence of laboratory-confirmed viral respiratory infection, the continuous wearing of N95 respirators (network OR, 0.48; 95% CrI: 0.27 to 0.86; SUCRA score, 85.4) showed more effective than the control group. However, in terms of reducing the incidence of CRI, there was no rPPE showing superior protective effectiveness.

CONCLUSIONS

There are significant differences in preventive efficacy among current rPPE. Our result suggests that continuous wearing of N95 respirators on the whole shift can serve as the best preventive rPPE for HCWs from the VRID.

Mg2+ Diffusion-Induced Structural and Property Evolution in Epitaxial Fe3O4 Thin Films

Epitaxial Fe₃O₄ thin films grown on single crystal MgO(001) present well-defined model systems to study fundamental multivalent ion diffusion and associated phase transition processes in transition-metal-oxide-based cathodes. In this work, we show at an atomic scale the Mg²⁺ diffusion pathways, kinetics, and reaction products at the Fe₃O₄/MgO heterostructures under different oxygen partial pressures but with the same thermal annealing conditions. Combining microscopic, optical, and spectroscopic techniques, we demonstrate that an oxygen-rich environment promotes facile Mg²⁺ incorporation into the Fe²⁺ sites, leading to the formation of Mg_1-xFe_2+xO₄ spinel structures, where the corresponding portion of the Fe²⁺ ions are oxidized to Fe³⁺. Conversely, annealing in vacuum results in the formation of a thin interfacial rocksalt layer (Mg_1-yFe_yO), which serves as a blocking layer leading to significantly reduced Mg²⁺ diffusion to the bulk Fe₃O₄. The observed changes in transport and optical properties as a result of Mg diffusion are interpreted in light of the electronic structures determined by X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. Our results reveal the critical role of available anions in governing cation diffusion in the spinel structures and the need to prevent formation of unwanted reaction intermediates for the promotion of facile cation diffusion.

Novel variants and uncommon cases among southern Chinese children with X-linked hypophosphatemia

PURPOSE

X-linked hypophosphatemia (XLH) is the most common inherited renal phosphate wasting disorder and is often misdiagnosed as vitamin D deficiency. This study aims to provide clinical and mutational characteristics of 65 XLH pediatric patients in southern China.

METHODS

In this work, a combination of DNA sequencing and qPCR analysis was used to study the PHEX gene in 80 pediatric patients diagnosed with hypophosphatemia. The clinical and laboratory data of confirmed 65 XLH patients were assessed and analyzed retrospectively.

RESULTS

In 65 XLH patients from 61 families, 51 different variants in the PHEX gene were identified, including 23 previously reported variants and 28 novel variants. In this cohort of XLH patients, the c.1601C>T(p.Pro534Leu) variant appears more frequently. Fourteen uncommon XLH cases were described, including four boys with de novo mosaic variants, eight patients with large deletions and a pair of monozygotic twins. The clinical manifestations in this cohort are very similar to those previously reported.

CONCLUSION

This study extends the mutational spectrum of the PHEX gene, which will contribute to accurate diagnosis. This study also suggests a supplementary qPCR or MLPA assay may be performed along with classical sequencing to confirm the gross insertion/deletion.

Phase Diagram and Superconducting Dome of Infinite-Layer Nd_{1-x}Sr_{x}NiO_{2} Thin Films

Infinite-layer Nd_{1-x}Sr_{x}NiO_{2} thin films with Sr doping level x from 0.08 to 0.3 are synthesized and investigated. We find a superconducting dome x between 0.12 and 0.235 accompanied by a weakly insulating behavior in both under- and overdoped regimes. The dome is akin to that in the electron-doped 214-type and infinite-layer cuprate superconductors. For x≥0.18, the normal state Hall coefficient (R_{H}) changes the sign from negative to positive as the temperature decreases. The temperature of the sign changes decreases monotonically with decreasing x from the overdoped side and approaches the superconducting dome at the midpoint, suggesting a reconstruction of the Fermi surface with the dopant concentration across the dome.

Molecular Beam Epitaxy of Two-Dimensional Vanadium-Molybdenum Diselenide Alloys

Two-dimensional (2D) alloys represent a versatile platform that extends the properties of atomically thin transition-metal dichalcogenides. Here, using molecular beam epitaxy, we investigate the growth of 2D vanadium-molybdenum diselenide alloys, V_xMo_1-xSe₂, on highly oriented pyrolytic graphite and unveil their structural, chemical, and electronic integrities via measurements by scanning tunneling microscopy/spectroscopy, synchrotron X-ray photoemission, and X-ray absorption spectroscopy (XAS). Essentially, we found a critical value of x = ∼0.44, below which phase separation occurs and above which a homogeneous metallic phase is favored. Another observation is an effective increase in the density of mirror twin boundaries of constituting MoSe₂ in the low V concentration regime (x ≤ 0.05). Density functional theory calculations support our experimental results on the thermal stability of 2D V_xMo_1-xSe₂ alloys and suggest an H phase of the homogeneous alloys with alternating parallel V and Mo strips randomly in-plane stacked. Element-specific XAS of the 2D alloys, which clearly indicates quenched atomic multiplets similar to the case of 2H-VSe₂, provides strong evidence for the H phase of the 2D alloys. This work provides a comprehensive understanding of the thermal stability, chemical state, and electronic structure of 2D V_xMo_1-xSe₂ alloys, useful for the future design of 2D electronic devices.

Back pain from painful osteoporotic vertebral fractures: discrepancy between the actual fracture location and the location suggested by patient-reported pain or physical examination findings

Caution is necessary when using symptom or physical examination findings to localize the osteoporotic vertebral fractures (VFs) attributable to the discrepant colocalized relationship.

INTRODUCTION

Whether the location of symptoms or physical examination findings delineates the appropriate spinal range for imaging has not been thoroughly investigated for VFs. The present study aims to analyze the consistency between the fractural vertebrae location and the location suggested by patient-reported pain or physical examination findings.

METHODS

This observational study, following a prospective design, enrolled 358 patients with VFs. The locations of two symptoms (patient-reported back pain [P-RBP], radiating pain [RP]) and findings from two physical examinations (spinal palpation tenderness [SPT], axial spinal percussion pain [ASPP]) were used to locate the VF segments identified using whole-spine magnetic resonance imaging (MRI). The percentage of agreements and kappa coefficient were calculated.

RESULTS

In 20.7% (74/358), the P-RBP site and VF segments were in the same location (kappa = 0.153); 21.2% (76/358) presented with concomitant RP in 93.4% (71/76) of whom the RP dermatome was colocalized with the VF segments (kappa = 0.924); 55.0% (197/358) and 23.2% (83/358) of patients presented with positive SPT and ASPP, respectively; and in 49.2% (97/197) and 96.4% (80/83) of patients with positive SPT (kappa = 0.435) and ASPP (kappa = 0.963), the positive finding and the VF segments were consistently colocalized.

CONCLUSIONS

The positive finding of RP or ASPP is useful in determining the spinal range for imaging tests, while an MRI scan covering the whole thoracic and lumbar spine is necessary in VF-suspected patients with P-RBP or positive SPT, indicating that caution is necessary when using symptoms or physical examination findings to localize VFs.

Interfacial Oxygen-Driven Charge Localization and Plasmon Excitation in Unconventional Superconductors

Charge localization is critical to the control of charge dynamics in systems such as perovskite solar cells, organic-, and nanostructure-based photovoltaics. However, the precise control of charge localization via electronic transport or defect engineering is challenging due to the complexity in reaction pathways and environmental factors. Here, charge localization in optimal-doped La_1.85 Sr_0.15 CuO₄ thin-film on SrTiO₃ substrate (LSCO/STO) is investigated, and also a high-energy plasmon is observed. Charge localization manifests as a near-infrared mid-gap state in LSCO/STO. This is ascribed to the interfacial hybridization between the Ti3d-orbitals of the substrate and O2p-orbitals of the film. The interfacial effect leads to significant changes in the many-body correlations and local-field effect. The local-field effect results in an inhomogeneous charge distribution, and due to perturbation by an external field, the high polarizability of this nonuniform charge system eventually generates the high-energy plasmon. Transformation of the electronic correlations in LSCO/STO is further demonstrated via temperature-dependent spectral-weight transfer. This study of charge localization in cuprates and interfacial hybridization provides important clues to their electronic structures and superconductive properties.

The invasion status of lymphovascular space and lymph nodes in cervical cancer assessed by mono-exponential and bi-exponential DWI-related parameters

AIM

To investigate whether mono-exponential and bi-exponential diffusion-weighted imaging (DWI)-related parameters of the primary tumour can evaluate the status of lymphovascular space invasion (LVSI) and lymph node metastasis (LNM) in patients with cervical carcinoma preoperatively.

MATERIALS AND METHODS

Eighty patients with cervical carcinoma were enrolled, who underwent preoperative multi b-value DWI and radical hysterectomy. They were classified into LVSI(+) versus LVSI(-) and LNM(+) versus LNM(-) according to postoperative pathology. The apparent diffusion coefficient (ADC), pure molecular diffusion (D), pseudo-diffusion coefficient (D∗), and perfusion fraction (f) were calculated from the whole tumour (__whole) and tumour margin (__margin). All parameters were compared between LVSI(+) and LVSI(-) and between LNM(+) and LNM(-). Logistic regression analysis and receiver operating characteristic (ROC) curve analysis were performed to evaluate the diagnostic performance of these parameters.

RESULTS

f__margin and D∗__whole showed significant differences in differentiating LVSI(+) from LVSI(-) tumours (p=0.002, 0.008, respectively), while LNM(+) tumours presented with significantly higher ADC__margin than that of LNM(-) tumours (p=0.009). The other parameters were not independent related factors with the status of LVSI or LNM according to logistic regression analysis (p>0.05). The area under the ROC curve of f__margin combined with D∗__whole in discriminating LVSI(+) from LVSI(-) was 0.826 (95% confidence interval [CI]: 0.691-0.961), while ADC__margin in differentiating LNM(+) from LNM(-) was 0.788 (95% CI: 0.648-0.928).

CONCLUSIONS

The parameters generated from mono-exponential and bi-exponential DWI of the primary cervical carcinoma could help discriminate its status regarding LVSI (f__margin and D∗__whole) and LNM (ADC__margin).

Hypomethylation of Notch1 DNA is associated with the occurrence of uveitis

Uveitis is a serious intra-ocular inflammatory disease that can lead to visual impairment even blindness worldwide. Notch signaling can regulate the differentiation of naive CD4⁺ T cells, influencing the development of uveitis. DNA methylation is closely related to the autoimmune diseases. In this study, we measured the Notch1 DNA methylation level, determined the Notch1 and related DNA methylases mRNA expression and evaluated the ratio of T helper type 17 regulatory T cell (Th17/T_reg ) in peripheral blood mononuclear cells (PBMCs) from uveitis patients and normal control subjects; we also tested the levels of relevant inflammatory cytokines in serum from the participants. Results indicated that compared with those in normal control individuals, the expression of ten-eleven translocation 2 (TET2) and Notch1 mRNA is elevated in uveitis patients, whereas the methylation level in Notch1 DNA promotor region [-842 ~ -646 base pairs (bp)] is down-regulated, and is unrelated to anatomical location. Moreover, the Th17/T_reg ratio is up-regulated in PBMCs from uveitis patients, accompanied by the elevated levels of proinflammatory cytokines [e.g. interleukin (IL)-2, IL-6, IL-17 and interferon (IFN)-γ] in serum from uveitis patients. These findings suggest that the over-expression of TET2 DNA demethylase may lead to hypomethylation of Notch1, activate the Notch1 signaling, induce naive CD4⁺ T cells to differentiate theTh17 subset and thus disturb the balance of the Th17/T_reg ratio in uveitis patients. Overall, hypomethylation of Notch1 DNA is closely associated with the occurrence of uveitis. Our study preliminarily reveals the underlying mechanism for the occurrence of uveitis related to the hypomethylation of Notch1 DNA, providing a novel therapeutic strategy against uveitis in clinical practice.

Enhanced Electrocatalytic Hydrogen Evolution Activity in Single-Atom Pt-Decorated VS2 Nanosheets

Enhancing catalytic activity by decorating noble metals in catalysts provides an opportunity for promoting the electrocatalytic hydrogen evolution reaction (HER) application. However, there are few systematic studies on regulating the structures of noble metals in catalytic materials and investigating their influence on HER. Herein, Pt catalysts with different structures including single atoms (SAs), clusters, and nanoparticles well-controllably anchored on VS₂ nanosheets through a cost-effective optothermal method are reported, and their HER performance is studied. The most efficient Pt-decorated VS₂ catalyst (with both Pt SAs and clusters) delivers an overpotential of 77 mV at 10 mA cm^-2, close to that of Pt/C (48 mV). However, the optimal mass activity of Pt (normalizing to Pt content) is obtained from only SA Pt-decorated VS₂ (i.e., 22.88 A mg_Pt^-1 at 200 mV) and is 12 times greater than that of the Pt/C (1.87 A mg_Pt^-1), attributed to the greatly enhanced Pt utilization. Additionally, the theoretical simulations reveal that Pt SA decoration makes the adsorption free energy of H* closer to the thermoneutral value and improves the charge-transfer kinetics, significantly enhancing HER activity. This work offers a pathway to prepare the desired catalyst based on synergy of Pt structures and VS₂ and reveals the intrinsic mechanism for enhancing catalytic activity, which is important for HER applications.

Anisotropic Collective Charge Excitations in Quasimetallic 2D Transition-Metal Dichalcogenides

The quasimetallic 1T' phase 2D transition-metal dichalcogenides (TMDs) consist of 1D zigzag metal chains stacked periodically along a single axis. This gives rise to its prominent physical properties which promises the onset of novel physical phenomena and applications. Here, the in-plane electronic correlations are explored, and new mid-infrared plasmon excitations in 1T' phase monolayer WSe2 and MoS2 are observed using optical spectroscopies. Based on an extensive first-principles study which analyzes the charge dynamics across multiple axes of the atomic-layered systems, the collective charge excitations are found to disperse only along the direction perpendicular to the chains. Further analysis reveals that the interchain long-range coupling is responsible for the coherent 1D charge dynamics and the spin-orbit coupling affects the plasmon frequency. Detailed investigation of these charge collective modes in 2D-chained systems offers opportunities for novel device applications and has implications for the underlying mechanism that governs superconductivity in 2D TMD systems.

[The consideration about study design and implementation of vaccine clinic trials]

The safety of prophylactic vaccine is one of the key points both in clinical trials and evaluation. Based on the review practice of vaccine registration clinical trials in recent years, we puts forward a series of thoughts and suggestions on the common problems of safety study on vaccine, including the hypothesis of safety study, the consideration of inclusion/exclusion criteria and suspension/termination criteria for study; the routine requirements of safety study and some special issue such as medical laboratory test index, vaccine virus shedding and safety of adjuvant, and further clarifies the requirements of safety observation on sequential enrollment; also emphasized the scientific judgment of causality and the quality of safety monitoring. It can be used for reference by vaccine researchers and to explore appropriate solutions to promote vaccine research & development and risk control in China.

[The consideration about safety data analysis and expression in instructions of vaccine clinic trials]

The safety of prophylactic vaccine is one of the key points both in clinical trials and evaluation. Based on the review practice of vaccine registration clinical trials in recent years, we summarized the common problems in safety analysis and report and accordingly puts forward a series of thoughts and suggestions, including discussing the role of statistics in safety analysis, putting forward the framework of safety analysis and report involved analysis content, analysis index and analysis dimension, in which attention is paid to the severity analysis; emphasizing the initiative analysis on risk signal and encouraging the evidence-based initiative safety evaluation. At the same time, this paper discusses the basic principles of the presentation of safety data in the package inserts, as well as the comprehensive consideration of the safety data of each phase of the trial and different subjects. It can be used for reference by sponsor to promote vaccine clinical research and evaluation in China.

A high throughput method for quantifying number and size distribution of Arabidopsis seeds using large particle flow cytometry

BACKGROUND

Seed size and number are important plant traits from an ecological and horticultural/agronomic perspective. However, in small-seeded species such as Arabidopsis thaliana, research on seed size and number is limited by the absence of suitable high throughput phenotyping methods.

RESULTS

We report on the development of a high throughput method for counting seeds and measuring individual seed sizes. The method uses a large-particle flow cytometer to count individual seeds and sort them according to size, allowing an average of 12,000 seeds/hour to be processed. To achieve this high throughput, post harvested seeds are first separated from remaining plant material (dust and chaff) using a rapid sedimentation-based method. Then, classification algorithms are used to refine the separation process in silico. Accurate identification of all seeds in the samples was achieved, with relative errors below 2%.

CONCLUSION

The tests performed reveal that there is no single classification algorithm that performs best for all samples, so the recommended strategy is to train and use multiple algorithms and use the median predictions of seed size and number across all algorithms. To facilitate the use of this method, an R package (SeedSorter) that implements the methodology has been developed and made freely available. The method was validated with seed samples from several natural accessions of Arabidopsis thaliana, but our analysis pipeline is applicable to any species with seed sizes smaller than 1.5 mm.

Electronic Modulation in Site-Selective Occupation of Quasi-2D Triangular-Lattice Cs2CuCl4-xBrx Perovskite Probed by Surface-Sensitive Characterization

A controllable electronic manipulation in a frustrated magnetic system such as solution-based two-dimensional (2D) all-inorganic perovskites offers a possible route for their integrations with electronic and magnetic devices for their advanced applications. Here, we perform element-specific investigations of an emergent class of quasi-2D all-inorganic perovskites Cs₂CuCl_4-xBr_x with (0 ≤ x ≤ 4) using a combination of synchrotron-radiation photoelectron techniques. Surface- and element-sensitive X-ray absorption spectroscopy spectra of Cu L_2,3 edges indicate strong electronic transition that is largely influenced by their halogen content at room temperature. This implies that site-selective occupation largely dominates the electronic transition across the unoccupied states of these series since chlorine atoms possess a stronger electronegative character than bromine atoms. Moreover, the implication of halogen site is reflected in the valence band of Cl-rich copper perovskite in which the valence band edge is closer to Fermi energy (E_F) than that of the Br-rich compound. Furthermore, X-ray magnetic circular dichroism spectra of mixed ratio and Br-rich compounds exhibit antiferromagnetism at room temperature. These site-specific magnetic-spectroscopic results are corroborated by density functional theory calculations. The strong electronic modulation and the local magnetic spectroscopy results in these solution-based and low-temperature-growth materials will pave the way toward energy- and cost-efficient perovskite devices.

Three-Dimensional Resonant Exciton in Monolayer Tungsten Diselenide Actuated by Spin-Orbit Coupling

The intricate features of many-body interactions and spin-orbit coupling play a significant role in numerous physical phenomena. Particularly in two-dimensional transition metal dichalcogenides (2D-TMDs), excitonic dynamics are a key phenomenon that promises opportunities for diverse range of device applications. Here, we report the direct observation of a visible-range three-dimensional resonant exciton and its associated charged exciton in monolayer tungsten diselenide, as compared to monolayer molybdenum disulfide. A comprehensive experimental study that includes high-resolution TEM, Raman, high-resolution spectroscopic ellipsometry over a wide temperature range down to 4 K, high-energy temperature, and excitation power-dependent photoluminescence spectroscopy has been conducted. It is supported by first-principles calculations to unravel the influence of spin-orbit coupling in the formation of the resonant exciton and to identify its in-plane and out-of-plane features. Furthermore, we study the impact of temperature and thickness on the spin-orbit coupling strength in 2D-TMDs. This work is crucial in creating a platform in the fundamental understanding of high-energy resonant exciton in layered two-dimensional systems and that such high-energy optoelectronic features make them an increasingly attractive candidate for novel electronic and optoelectronic applications particularly in the aspects of solar cells and light-emitting diodes via the manipulation of excitonic states.

Comparison of Hogan pharyngeal flap and sphincter pharyngoplasty in postoperative velopharyngeal function

The purpose of this study was to compare speech and breathing after sphincter pharyngoplasty and the Hogan pharyngeal flap in the management of cleft-related velopharyngeal insufficiency (VPI). We reviewed 78 patients with VPI who had either the Hogan flap (n=30) or sphincter pharyngoplasty (n=48) between 2009 and 2011. Velopharyngeal function, nasal patency, and speech were compared. In the Hogan flap group, 25 patients had achieved velopharyngeal competence and nine had normal speech. In the sphincter pharyngoplasty group, 29 patients achieved velopharyngeal competence and 20 normal speech. The Hogan flap group had a higher rate of velopharyngeal competence (n=25) than the sphincter pharyngoplasty group (p=0.033), but there was no significant difference in intelligibility of speech. Eighteen patients in the Hogan flap group and 33 in the sphincter pharyngoplasty group reported symptoms of snoring, with no significant difference in nasal ventilation. Our results suggest that a posterior pharyngeal flap is a more effective technique for managing VPI after repair of cleft palate than sphincter pharyngoplasty, and causes no more postoperative complications in nasal breathing.

Metallic 1T Phase, 3d1 Electronic Configuration and Charge Density Wave Order in Molecular Beam Epitaxy Grown Monolayer Vanadium Ditelluride

We present a combined experimental and theoretical study of monolayer vanadium ditelluride, VTe₂, grown on highly oriented pyrolytic graphite by molecular-beam epitaxy. Using various in situ microscopic and spectroscopic techniques, including scanning tunneling microscopy/spectroscopy, synchrotron X-ray and angle-resolved photoemission, and X-ray absorption, together with theoretical analysis by density functional theory calculations, we demonstrate direct evidence of the metallic 1T phase and 3d¹ electronic configuration in monolayer VTe₂ that also features a (4 × 4) charge density wave order at low temperatures. In contrast to previous theoretical predictions, our element-specific characterization by X-ray magnetic circular dichroism rules out a ferromagnetic order intrinsic to the monolayer. Our findings provide essential knowledge necessary for understanding this interesting yet less explored metallic monolayer in the emerging family of van der Waals magnets.