Engineering of robust topological quantum phases in graphene nanoribbons.

Boundaries between distinct topological phases of matter support robust, yet exotic quantum states such as spin-momentum locked transport channels or Majorana fermions1-3. The idea of using such states in spintronic devices or as qubits in quantum information technology is a strong driver of current research in condensed matter physics4-6. The topological properties of quantum states have helped to explain the conductivity of doped trans-polyacetylene in terms of dispersionless soliton states7-9. In their seminal paper, Su, Schrieffer and Heeger (SSH) described these exotic quantum states using a one-dimensional tight-binding model10,11. Because the SSH model describes chiral topological insulators, charge fractionalization and spin-charge separation in one dimension, numerous efforts have been made to realize the SSH Hamiltonian in cold-atom, photonic and acoustic experimental configurations12-14. It is, however, desirable to rationally engineer topological electronic phases into stable and processable materials to exploit the corresponding quantum states. Here we present a flexible strategy based on atomically precise graphene nanoribbons to design robust nanomaterials exhibiting the valence electronic structures described by the SSH Hamiltonian15-17. We demonstrate the controlled periodic coupling of topological boundary states18 at junctions of graphene nanoribbons with armchair edges to create quasi-one-dimensional trivial and non-trivial electronic quantum phases. This strategy has the potential to tune the bandwidth of the topological electronic bands close to the energy scale of proximity-induced spin-orbit coupling19 or superconductivity20, and may allow the realization of Kitaev-like Hamiltonians3 and Majorana-type end states21.

Steering Large Magnetic Exchange Coupling in Nanographenes near the Closed-Shell to Open-Shell Transition.

The design of open-shell carbon-based nanomaterials is at the vanguard of materials science, steered by their beneficial magnetic properties like weaker spin-orbit coupling than that of transition metal atoms and larger spin delocalization, which are of potential relevance for future spintronics and quantum technologies. A key parameter in magnetic materials is the magnetic exchange coupling (MEC) between unpaired spins, which should be large enough to allow device operation at practical temperatures. In this work, we theoretically and experimentally explore three distinct families of nanographenes (NGs) (A, B, and C) featuring majority zigzag peripheries. Through many-body calculations, we identify a transition from a closed-shell ground state to an open-shell ground state upon an increase of the molecular size. Our predictions indicate that the largest MEC for open-shell NGs occurs in proximity to the transition between closed-shell and open-shell states. Such predictions are corroborated by the on-surface syntheses and structural, electronic, and magnetic characterizations of three NGs (A[3,5], B[4,5], and C[4,3]), which are the smallest open-shell systems in their respective chemical families and are thus located the closest to the transition boundary. Notably, two of the NGs (B[4,5] and C[4,3]) feature record values of MEC (close to 200 meV) measured on the Au(111) surface. Our strategy for maximizing the MEC provides perspectives for designing carbon nanomaterials with robust magnetic ground states.

N=8 Armchair Graphene Nanoribbons: Solution Synthesis and High Charge Carrier Mobility.

Structurally defined graphene nanoribbons (GNRs) have emerged as promising candidates for nanoelectronic devices. Low band gap (<1 eV) GNRs are particularly important when considering the Schottky barrier in device performance. Here, we demonstrate the first solution synthesis of 8-AGNRs through a carefully designed arylated polynaphthalene precursor. The efficiency of the oxidative cyclodehydrogenation of the tailor-made polymer precursor into 8-AGNRs was validated by FT-IR, Raman, and UV/Vis-near-infrared (NIR) absorption spectroscopy, and further supported by the synthesis of naphtho[1,2,3,4-ghi]perylene derivatives (1 and 2) as subunits of 8-AGNR, with a width of 0.86 nm as suggested by the X-ray single crystal analysis. Low-temperature scanning tunneling microscopy (STM) and solid-state NMR analyses provided further structural support for 8-AGNR. The resulting 8-AGNR exhibited a remarkable NIR absorption extending up to ∼2400 nm, corresponding to an optical band gap as low as ∼0.52 eV. Moreover, optical-pump TeraHertz-probe spectroscopy revealed charge-carrier mobility in the dc limit of ∼270 cm2  V-1 s-1 for the 8-AGNR.

Tuning interfacial charge transfer in atomically precise nanographene-graphene heterostructures by engineering van der Waals interactions.

Combining strong light absorption and outstanding electrical conductivity, hybrid nanographene-graphene (NG-Gr) van der Waals heterostructures (vdWHs) represent an emerging material platform for versatile optoelectronic devices. Interfacial charge transfer (CT), a fundamental process whose full control remains limited, plays a paramount role in determining the final device performance. Here, we demonstrate that the interlayer vdW interactions can be engineered by tuning the sizes of bottom-up synthesized NGs to control the interfacial electronic coupling strength and, thus, the CT process in NG-Gr vdWHs. By increasing the dimensions of NGs from 42 to 96 sp2 carbon atoms in the polyaromatic core to enhance the interfacial coupling strength, we find that the CT efficiency and rate in NG-Gr vdWHs display a drastic increase of one order of magnitude, despite the fact that the interfacial energy driving the CT process is unfavorably reduced. Our results shed light on the CT mechanism and provide an effective knob to tune the electronic coupling at NG-Gr interfaces by controlling the size-dependent vdW interactions.

Impact of video-led educational intervention on uptake of influenza vaccine among the elderly in western China: a community-based randomized controlled trial.

BACKGROUND: Influenza vaccination coverage rate among the elderly is low in China. We aimed to evaluate the impact of video-led educational intervention on influenza vaccine uptake among the Chinese elderly. METHODS: A randomized controlled trial was conducted in 8 communities of Xi'an, a representative city in western China. Elderly aged over 60 years were randomized to the control group and intervention group (12-minute video education on influenza and its vaccination). Participants' knowledge, attitudes, and practices (KAP) of influenza was assessed by using a questionnaire survey before and after the intervention. The primary outcomes were participants' willingness to get influenza vaccinated and their actual uptake rates in the 2020-21 flu season. Secondary outcomes were the variations of pre- and post-intervention KAP scores. Intention-to-treat analysis was performed to analyze the data, and sensitivity analyses were conducted to examine the robustness of the results. RESULTS: A total of 350 people were enrolled, with 175 individuals for each group. Participants in the intervention group were more willing to receive influenza vaccination than those in the control group (64.6% vs. 51.4%, p<0.05). The influenza vaccination uptake rate occurred in 10.3% of participants in the intervention group and 3.4% in the control group (odds ratio, 3.23; 95% CI 1.25-8.32, p<0.001). The post-intervention KAP scores in the intervention group were significantly higher compared to those in the control group (p<0.001). CONCLUSION: Video-led education was an effective and feasible approach to improve old people's willingness and uptake of influenza vaccination in western China.

Synthesis of Nonplanar Graphene Nanoribbon with Fjord Edges.

As a new family of semiconductors, graphene nanoribbons (GNRs), nanometer-wide strips of graphene, have appeared as promising candidates for next-generation nanoelectronics. Out-of-plane deformation of π-frames in GNRs brings further opportunities for optical and electronic property tuning. Here we demonstrate a novel fjord-edged GNR (FGNR) with a nonplanar geometry obtained by regioselective cyclodehydrogenation. Triphenanthro-fused teropyrene 1 and pentaphenanthro-fused quateropyrene 2 were synthesized as model compounds, and single-crystal X-ray analysis revealed their helically twisted conformations arising from the [5]helicene substructures. The structures and photophysical properties of FGNR were investigated by mass spectrometry and UV-vis, FT-IR, terahertz, and Raman spectroscopic analyses combined with theoretical calculations.

Solution-Processed Graphene-Nanographene van der Waals Heterostructures for Photodetectors with Efficient and Ultralong Charge Separation.

Sensitization of graphene with inorganic semiconducting nanostructures has been demonstrated as a powerful strategy to boost its optoelectronic performance. However, the limited tunability of optical properties and toxicity of metal cations in the inorganic sensitizers prohibits their widespread applications, and the in-depth understanding of the essential interfacial charge-transfer process within such hybrid systems remains elusive. Here, we design and develop high-quality nanographene (NG) dispersions with a large-scale production using high-shear mixing exfoliation. The physisorption of these NG molecules onto graphene gives rise to the formation of graphene-NG van der Waals heterostructures (VDWHs), characterized by strong interlayer coupling through π-π interactions. As a proof of concept, photodetectors fabricated on the basis of such VDWHs show ultrahigh responsivity up to 4.5 × 107 A/W and a specific detectivity reaching 4.6 × 1013 Jones, being competitive with the highest values obtained for graphene-based photodetectors. The outstanding device characteristics are attributed to the efficient transfer of photogenerated holes from NGs to graphene and the long-lived charge separation at graphene-NG interfaces (beyond 1 ns), as elucidated by ultrafast terahertz (THz) spectroscopy. These results demonstrate the great potential of such graphene-NG VDWHs as prototypical building blocks for high-performance, low-toxicity optoelectronics.

Impact of video-led educational intervention on the uptake of influenza vaccine among adults aged 60 years and above in China: a study protocol for a randomized controlled trial.

BACKGROUND: Influenza is a global health threat to older adults, and the influenza vaccine is the most effective approach to prevent influenza infection. However, influenza vaccination coverage among Chinese older adults is far less than in developed countries such as the United States (4.0% vs. 64.9%). This study aims to increase influenza vaccination coverage in Chinese adults ≥60 years using a video-led educational intervention conducted by medical students. METHODS: A cluster randomized controlled trial will be conducted in 4 districts of Xi'an city, Shaanxi Province, China, using a stratified sampling approach. Adults aged ≥60 years will be recruited from 8 community hospitals. A self-administered questionnaire of knowledge, attitudes, and practices (KAP) will be employed to record the KAP score. During the 6-month interventional period, participants in the intervention group will receive educational videos focused on influenza and influenza vaccination, coupled with a group discussion conducted by the medical students. For those in the control group, no intervention will be provided. The outcomes measured in both groups will be the influenza vaccination coverage and the KAP scores of all participants. DISCUSSION: Medical students are more likely to educate older adults about scientific knowledge of influenza and its vaccine compared to clinical practitioners, who, most of the time, remain over-occupied due to the extensive workload. Video-led counseling and education could be a useful option to optimize older adults' understanding of influenza and influenza vaccination. This eventually could improve the uptake of influenza vaccine among Chinese older adults. TRIAL REGISTRATION: Chinese Clinical Trial Registry; ChiCTR2000034330 ; Registered 3rd July 2019.

Coupled Spin States in Armchair Graphene Nanoribbons with Asymmetric Zigzag Edge Extensions.

Exact positioning of sublattice imbalanced nanostructures in graphene nanomaterials offers a route to control interactions between induced local magnetic moments and to obtain graphene nanomaterials with magnetically nontrivial ground states. Here, we show that such sublattice imbalanced nanostructures can be incorporated along a large band gap armchair graphene nanoribbon on the basis of asymmetric zigzag edge extensions, achieved by incorporating specifically designed precursor monomers. Scanning tunneling spectroscopy of an isolated and electronically decoupled zigzag edge extension reveals Hubbard-split states in accordance with theoretical predictions. Mean-field Hubbard-based modeling of pairs of such zigzag edge extensions reveals ferromagnetic, antiferromagnetic, or quenching of the magnetic interactions depending on the relative alignment of the asymmetric edge extensions. Moreover, a ferromagnetic spin chain is demonstrated for a periodic pattern of zigzag edge extensions along the nanoribbon axis. This work opens a route toward the fabrication of graphene nanoribbon-based spin chains with complex magnetic ground states.

Large-Cavity Coronoids with Different Inner and Outer Edge Structures.

Coronoids, polycyclic aromatic hydrocarbons with geometrically defined cavities, are promising model structures of porous graphene. Here, we report the on-surface synthesis of C168 and C140 coronoids, referred to as [6]- and [5]coronoid, respectively, using 5,9-dibromo-14-phenylbenzo[m]tetraphene as the precursor. These coronoids entail large cavities (>1 nm) with inner zigzag edges, distinct from their outer armchair edges. While [6]coronoid is planar, [5]coronoid is not. Low-temperature scanning tunneling microscopy/spectroscopy and noncontact atomic force microscopy unveil structural and electronic properties in accordance with those obtained from density functional theory calculations. Detailed analysis of ring current effects identifies the rings with the highest aromaticity of these coronoids, whose pattern matches their Clar structure. The pores of the obtained coronoids offer intriguing possibilities of further functionalization toward advanced host-guest applications.

Heteroatom-Doped Nanographenes with Structural Precision.

Nanographenes, which are defined as nanoscale (1-100 nm) graphene cutouts, include quasi-one-dimensional graphene nanoribbons (GNRs) and quasi-zero-dimensional graphene quantum dots (GQDs). Polycyclic aromatic hydrocarbons (PAHs) larger than 1 nm can be viewed as GQDs with atomically precise molecular structures and can thus be termed nanographene molecules. As a result of quantum confinement, nanographenes are promising for next-generation semiconductor applications with finite band gaps, a significant advantage compared with gapless two-dimensional graphene. Similar to the atomic doping strategy in inorganic semiconductors, incorporation of heteroatoms into nanographenes is a viable way to tune their optical, electronic, catalytic, and magnetic properties. Such properties are highly dependent not only on the molecular size and edge structure but also on the heteroatom type, doping position, and concentration. Therefore, reliable synthetic methods are required to precisely control these structural features. In this regard, bottom-up organic synthesis provides an indispensable way to achieve structurally well-defined heteroatom-doped nanographenes. Polycyclic heteroaromatic compounds have attracted great attention of organic chemists for decades. Research in this direction has been further promoted by modern interest in supramolecular chemistry and organic electronics. The rise of graphene in the 21st century has endowed large polycyclic heteroaromatic compounds with a new role as model systems for heteroatom-doped graphene. Heteroatom-doped nanographene molecules are in their own right promising materials for photonic, optoelectronic, and spintronic applications because of the extended π conjugation. Despite the significant advances in polycyclic heteroaromatic compounds, heteroatom-doped nanographene molecules with sizes of over 1 nm and their relevant GNRs are still scarce. In this Account, we describe the synthesis and properties of large heteroatom-doped nanographenes, mainly summarizing relevant advances in our group in the past decade. We first present several examples of heteroatom doping based on the prototypical nanographene molecule, i.e., hexa-peri-hexabenzocoronene (HBC), including nitrogen-doped HBC analogues by formal replacement of benzene with other heterocycles (e.g., aromatic pyrimidine and pyrrole and antiaromatic pyrazine) and sulfur-doped nanographene molecules via thiophene annulation. We then introduce heteroatom-doped zigzag edges and a variety of zigzag-edged nanographene molecules incorporating nitrogen, boron, and oxygen atoms. We finally summarize heteroatom-doped GNRs based on the success in the molecular cases. We hope that this Account will further stimulate the synthesis and applications of heteroatom-doped nanographenes with a combined effort from different disciplines.

Nanographenes: Ultrastable, Switchable, and Bright Probes for Super-Resolution Microscopy.

Super-resolution fluorescence microscopy has enabled important breakthroughs in biology and materials science. Implementations such as single-molecule localization microscopy (SMLM) and minimal emission fluxes (MINFLUX) microscopy in the localization mode exploit fluorophores that blink, i.e., switch on and off, stochastically. Here, we introduce nanographenes, namely large polycyclic aromatic hydrocarbons that can also be regarded as atomically precise graphene quantum dots, as a new class of fluorophores for super-resolution fluorescence microscopy. Nanographenes exhibit outstanding photophysical properties: intrinsic blinking even in air, excellent fluorescence recovery, and stability over several months. As a proof of concept for super-resolution applications, we use nanographenes in SMLM to generate 3D super-resolution images of silica nanocracks. Our findings open the door for the widespread application of nanographenes in super-resolution fluorescence microscopy.

Regioselective Hydrogenation of a 60-Carbon Nanographene Molecule toward a Circumbiphenyl Core.

Regioselective peripheral hydrogenation of a nanographene molecule with 60 contiguous sp2 carbons provides unprecedented access to peralkylated circumbiphenyl (1). Conversion to the circumbiphenyl core structure was unambiguously validated by MALDI-TOF mass spectrometry, NMR, FT-IR, and Raman spectroscopy. UV-vis absorption spectra and DFT calculations demonstrated the significant change of the optoelectronic properties upon peripheral hydrogenation. Stimulated emission from 1, observed via ultrafast transient absorption measurements, indicates potential as an optical gain material.

A TPD-based determination of the graphite interlayer cohesion energy.

Temperature Programmed Desorption (TPD) spectroscopy was used to determine the binding energies of polycyclic aromatic hydrocarbons C n H m (22 ≤ n ≤ 60) with highly oriented pyrolytic graphite. These energies were then used to estimate the dispersive graphite interlayer cohesion by means of a refined extrapolation method proposed by Björk et al. This yields a cohesion energy of 44.0 ± 3.8 meV per carbon atom. We discuss some limits of the TPD-based approach and contrast our values with previous determinations of the interlayer cohesion energy of graphite.

Expanding roles of circRNAs in cardiovascular diseases.

CircRNAs are a class of single-stranded RNAs characterized by covalently looped structures. Emerging advances have promoted our understanding of circRNA biogenesis, nuclear export, biological functions, and functional mechanisms. Roles of circRNAs in diverse diseases have been increasingly recognized in the past decade, with novel approaches in bioinformatics analysis and new strategies in modulating circRNA levels, which have made circRNAs the hot spot for therapeutic applications. Moreover, due to the intrinsic features of circRNAs such as high stability, conservation, and tissue-/stage-specific expression, circRNAs are believed to be promising prognostic and diagnostic markers for diseases. Aiming cardiovascular disease (CVD), one of the leading causes of mortality worldwide, we briefly summarize the current understanding of circRNAs, provide the recent progress in circRNA functions and functional mechanisms in CVD, and discuss the future perspectives both in circRNA research and therapeutics based on existing knowledge.

Immunization-related stress and stress-related responses of mucosal versus intramuscular COVID-19 vaccination among adults in China.

BACKGROUND: In late 2022, China became the first country to roll out mucosal COVID-19 vaccines. No prior study has yet compared the immunization stress-related responses (ISRR) among different routes of COVID-19 vaccine delivery. We aimed to compare the immunization-related psychological stress and ISRR between mucosal and intramuscular COVID-19 vaccines. METHODS: A cross-sectional questionnaire survey using a biopsychosocial framework design was performed from January 11 to 20, 2023. Adults with COVID-19 vaccination were eligible for the study, and a total of 1073 adults participated with community-based sample. Primary outcomes were the psychological stress levels and prevalence of ISRR. Multivariate regression models were employed to compare these outcomes between the two vaccination groups. The potential mediating effects of stress on vaccination and ISRR were examined using bootstrap sampling method. To further ensure the robustness of our results, sensitivity analysis with propensity score matching was performed. FINDINGS: In the univariate analysis, participants who received mucosal vaccination reported significantly lower stress levels compared to those who received intramuscular vaccination (3.39 ± 3.02 vs. 3.93 ± 3.24, P = .006). The prevalence of overall ISRR was significantly lower in the mucosal group compared to the intramuscular group (38.4% vs. 47.9%, P = .002). Multivariate regression models revealed that participants who received mucosal vaccination had a significantly lower stress level (ß = -0.516, 95% CI: -0.852 to -0.180; P = .003) and 38.7% fewer overall ISRR (OR = 0.613, 95% CI: 0.427 to 0.881; P = .008), particularly in terms of neurological symptoms. The immunization-related stress mediated the association between vaccination type and ISRR, with indirect effects estimated at 0.0663 (95% CI: 0.0195 to 0.1346) for overall ISRR. CONCLUSIONS: Mucosal COVID-19 vaccination was associated with reduced psychological stress and physical responses, as compared to intramuscular vaccination, which may contribute to increased trust and compliance with routine or mass vaccination efforts in the future.

Emissive brightening in molecular graphene nanoribbons by twilight states.

Carbon nanomaterials are expected to be bright and efficient emitters, but structural disorder, intermolecular interactions and the intrinsic presence of dark states suppress their photoluminescence. Here, we study synthetically-made graphene nanoribbons with atomically precise edges and which are designed to suppress intermolecular interactions to demonstrate strong photoluminescence in both solutions and thin films. The resulting high spectral resolution reveals strong vibron-electron coupling from the radial-breathing-like mode of the ribbons. In addition, their cove-edge structure produces inter-valley mixing, which brightens conventionally-dark states to generate hitherto-unrecognised twilight states as predicted by theory. The coupling of these states to the nanoribbon phonon modes affects absorption and emission differently, suggesting a complex interaction with both Herzberg-Teller and Franck- Condon coupling present. Detailed understanding of the fundamental electronic processes governing the optical response will help the tailored chemical design of nanocarbon optical devices, via gap tuning and side-chain functionalisation.

Ascites exosomal lncRNA PLADE enhances platinum sensitivity by inducing R-loops in ovarian cancer.

Cisplatin resistance is a major cause of therapeutic failure in patients with high-grade serous ovarian cancer (HGSOC). Long noncoding RNAs (lncRNAs) have emerged as key regulators of human cancers; however, their modes of action in HGSOC remain largely unknown. Here, we provide evidence to demonstrate that lncRNA Platinum sensitivity-related LncRNA from Ascites-Derived Exosomes (PLADE) transmitted by ascites exosomes enhance platinum sensitivity in HGSOC. PLADE exhibited significantly decreased expression in ascites exosomes and tumor tissues, as well as in the corresponding metastatic tumors from patients with HGSOC cisplatin-resistance. Moreover, HGSOC patients with higher PLADE expression levels exhibited longer progression-free survival. Gain- and loss-of-function studies have revealed that PLADE promotes cisplatin sensitivity by suppressing cell proliferation, migration and invasion, and enhancing apoptosis in vitro and in vivo. Furthermore, the functions of PLADE in increasing cisplatin sensitivity were proven to be transferred by exosomes to the cultured recipient cells and to the adjacent tumor tissues in mouse models. Mechanistically, PLADE binds to and downregulates heterogeneous nuclear ribonucleoprotein D (HNRNPD) by VHL-mediated ubiquitination, thus inducing an increased amount of RNA: DNA hybrids (R-loop) and DNA damage, consequently promoting cisplatin sensitivity in HGSOC. Collectively, these results shed light on the understanding of the vital roles of long noncoding RNAs in cancers.

Liver indicators affecting the relationship between BMI and hypertension in type 2 diabetes: a mediation analysis.

BACKGROUND: Body mass index (BMI) is an important risk factor for hypertension in diabetic patients. However, the underlying mechanisms remain poorly understood. Although liver-derived biological intermediates may play irreplaceable roles in the pathophysiology of diabetes, few studies have explored them in the association between BMI and hypertension in diabetes. OBJECTIVE: To investigate the role of liver enzymes in mediating the relationship between BIM exposure and hypertension in type 2 diabetes mellitus (T2DM). METHODS: We included a total of 1765 participants from the China National Diabetic Chronic Complications Study Cohort. Associations between liver enzymes and hypertension were estimated using multivariable regression models. The function of liver indicators in the relationship between BMI and hypertension was assessed using mediation analysis. Mediation analysis was conducted, taking into account age, diabetes duration, current smoking, fasting plasma glucose level, glycated hemoglobin, anti-diabetic therapy, and family history of diseases, including diabetes, hypertension, obesity, and hyperlipidemia. RESULTS: For men, the association of BMI with hypertension was partially mediated by alanine aminotransferase (ALT), with a proportion of mediation was 68.67%, by aspartate aminotransferase (AST) was 27.02%, and by γ-glutamyltransferase (GGT) was 38.58%, by AST/ALT was 63.35%; for women, the proportion mediated by ALT was 36.93%, and by AST was 37.47%, and GGT was 44.60%, and AST/ALT was 43.73% for BMI (all P < 0.05). CONCLUSION: The effect of BMI on hypertension is partly mediated by liver indicators (ALT, AST, GGT, and AST/ALT) in diabetic patients. Our results may provide opportunities to identify new targets for hypertension interventions.