Visualization of oxygen vacancies and self-doped ligand holes in La3Ni2O7-δ.

The recent discovery of superconductivity in La3Ni2O7-δ under high pressure with a transition temperature around 80 K (ref. 1) has sparked extensive experimental2-6 and theoretical efforts7-12. Several key questions regarding the pairing mechanism remain to be answered, such as the most relevant atomic orbitals and the role of atomic deficiencies. Here we develop a new, energy-filtered, multislice electron ptychography technique, assisted by electron energy-loss spectroscopy, to address these critical issues. Oxygen vacancies are directly visualized and are found to primarily occupy the inner apical sites, which have been proposed to be crucial to superconductivity13,14. We precisely determine the nanoscale stoichiometry and its correlation to the oxygen K-edge spectra, which reveals a significant inhomogeneity in the oxygen content and electronic structure within the sample. The spectroscopic results also reveal that stoichiometric La3Ni2O7 has strong charge-transfer characteristics, with holes that are self-doped from Ni sites into O sites. The ligand holes mainly reside on the inner apical O and the planar O, whereas the density on the outer apical O is negligible. As the concentration of O vacancies increases, ligand holes on both sites are simultaneously annihilated. These observations will assist in further development and understanding of superconducting nickelate materials. Our imaging technique for quantifying atomic deficiencies can also be widely applied in materials science and condensed-matter physics.

Phylogenomic analysis of 343 Xanthomonas citri pv. citri strains unravels introduction history and dispersal paths.

Xanthomonas citri pv. citri (Xcc) causes the devastating citrus canker disease. Xcc is known to have been introduced into Florida, USA in at least three different events in 1915, 1986 and 1995 with the first two claimed to be eradicated. It was questioned whether the Xcc introduction in 1986 has been successfully eradicated. Furthermore, it is unknown how Xcc has spread throughout the citrus groves in Florida. In this study, we investigated the population structure of Xcc to address these questions. We sequenced the whole genome of 343 Xcc strains collected from Florida groves between 1997 and 2016. Our analysis revealed two distinct clusters of Xcc. Our data strongly indicate that the claimed eradication of the 1986 Xcc introduction was not successful and Xcc strains from 1986 introduction were present in samples from at least 8 counties collected after 1994. Importantly, our data revealed that the Cluster 2 strains, which are present in all 20 citrus-producing counties sampled in Florida, originated from the Xcc introduction event in the Miami area in 1995. Our data suggest that Polk County is the epicenter of the dispersal of Cluster 2 Xcc strains, which is consistent with the fact that three major hurricanes passed through Polk County in 2004. As copper-based products have been extensively used to control citrus canker, we also investigated whether Xcc strains have developed resistance to copper. Notably, none of the 343 strains contained known copper resistance genes. Twenty randomly selected Xcc strains displayed sensitivity to copper. Overall, this study provides valuable insights into the introduction, eradication, spread, and copper resistance of Xcc in Florida.

Gate-Controlled Neuromorphic Functional Transition in an Electrochemical Graphene Transistor.

Neuromorphic devices have attracted significant attention as potential building blocks for the next generation of computing technologies owing to their ability to emulate the functionalities of biological nervous systems. The essential components in artificial neural networks such as synapses and neurons are predominantly implemented by dedicated devices with specific functionalities. In this work, we present a gate-controlled transition of neuromorphic functions between artificial neurons and synapses in monolayer graphene transistors that can be employed as memtransistors or synaptic transistors as required. By harnessing the reliability of reversible electrochemical reactions between carbon atoms and hydrogen ions, we can effectively manipulate the electric conductivity of graphene transistors, resulting in a high on/off resistance ratio, a well-defined set/reset voltage, and a prolonged retention time. Overall, the on-demand switching of neuromorphic functions in a single graphene transistor provides a promising opportunity for developing adaptive neural networks for the upcoming era of artificial intelligence and machine learning.

Evaluation of disease severity and prediction of severe cases in children hospitalized with influenza A (H1N1) infection during the post-COVID-19 era: a multicenter retrospective study.

BACKGROUND: The rebound of influenza A (H1N1) infection in post-COVID-19 era recently attracted enormous attention due the rapidly increased number of pediatric hospitalizations and the changed characteristics compared to classical H1N1 infection in pre-COVID-19 era. This study aimed to evaluate the clinical characteristics and severity of children hospitalized with H1N1 infection during post-COVID-19 period, and to construct a novel prediction model for severe H1N1 infection. METHODS: A total of 757 pediatric H1N1 inpatients from nine tertiary public hospitals in Yunnan and Shanghai, China, were retrospectively included, of which 431 patients diagnosed between February 2023 and July 2023 were divided into post-COVID-19 group, while the remaining 326 patients diagnosed between November 2018 and April 2019 were divided into pre-COVID-19 group. A 1:1 propensity-score matching (PSM) was adopted to balance demographic differences between pre- and post-COVID-19 groups, and then compared the severity across these two groups based on clinical and laboratory indicators. Additionally, a subgroup analysis in the original post-COVID-19 group (without PSM) was performed to investigate the independent risk factors for severe H1N1 infection in post-COIVD-19 era. Specifically, Least Absolute Shrinkage and Selection Operator (LASSO) regression was applied to select candidate predictors, and logistic regression was used to further identify independent risk factors, thus establishing a prediction model. Receiver operating characteristic (ROC) curve and calibration curve were utilized to assess discriminative capability and accuracy of the model, while decision curve analysis (DCA) was used to determine the clinical usefulness of the model. RESULTS: After PSM, the post-COVID-19 group showed longer fever duration, higher fever peak, more frequent cough and seizures, as well as higher levels of C-reactive protein (CRP), interleukin 6 (IL-6), IL-10, creatine kinase-MB (CK-MB) and fibrinogen, higher mechanical ventilation rate, longer length of hospital stay (LOS), as well as higher proportion of severe H1N1 infection (all P < 0.05), compared to the pre-COVID-19 group. Moreover, age, BMI, fever duration, leucocyte count, lymphocyte proportion, proportion of CD3+ T cells, tumor necrosis factor α (TNF-α), and IL-10 were confirmed to be independently associated with severe H1N1 infection in post-COVID-19 era. A prediction model integrating these above eight variables was established, and this model had good discrimination, accuracy, and clinical practicability. CONCLUSIONS: Pediatric H1N1 infection during post-COVID-19 era showed a higher overall disease severity than the classical H1N1 infection in pre-COVID-19 period. Meanwhile, cough and seizures were more prominent in children with H1N1 infection during post-COVID-19 era. Clinicians should be aware of these changes in such patients in clinical work. Furthermore, a simple and practical prediction model was constructed and internally validated here, which showed a good performance for predicting severe H1N1 infection in post-COVID-19 era.

Dynamics of rhizosphere microbial structure and function associated with the biennial bearing of moso bamboo.

Moso bamboo (Phyllostachys edulis) is a valuable nontimber forestry product with a biennial cycle, producing abundant bamboo shoots within one year (on-year) and few shoots within the following year (off-year). Moso bamboo plants undergo clonal reproduction, resulting in similar genetic backgrounds. However, the number of moso bamboo shoots produced each year varies. Despite this variation, the impact of soil nutrients and the root microbiome on the biennial bearing of moso bamboo is poorly understood. We collected 139 soil samples and determined 14 major physicochemical properties of the rhizosphere, rhizoplane, and bulk soil in different seasons (i.e., the growing and deciduous seasons) and different years (i.e., on- and off-years). Based on 16S rRNA and metagenomic sequencing, major variations were found in the rhizospheric microbial composition during different seasons and years in the moso bamboo forest. Environmental driver analysis revealed that essential nutrients (i.e., SOC, TOC, TN, P, and NH4+) were the main drivers of the soil microbial community composition and were correlated with the on- and off-year cycles. Moreover, 19 MAGs were identified as important biomarkers that could distinguish on- and off-years. We found that both season and year influenced both the microbial community structure and functional pathways through the biosynthesis of nutrients that potentially interact with the moso bamboo growth rhythm, especially the on-year root-associated microbiome, which had a greater abundance of specific nutrients such as gibberellins and vitamin B6. This work provides a dynamic perspective of the differential responses of various on- and off-year microbial communities and enhances our understanding of bamboo soil microbiome biodiversity and stability.

Controlling the Zero Hall Plateau in a Quantum Anomalous Hall Insulator by In-Plane Magnetic Field.

We investigate the quantum anomalous Hall plateau transition in the presence of independent out-of-plane and in-plane magnetic fields. The perpendicular coercive field, zero Hall plateau width, and peak resistance value can all be systematically controlled by the in-plane magnetic field. The traces taken at various fields almost collapse into a single curve when the field vector is renormalized to an angle as a geometric parameter. These results can be explained consistently by the competition between magnetic anisotropy and in-plane Zeeman field, and the close relationship between quantum transport and magnetic domain structure. The accurate control of zero Hall plateau facilitates the search for chiral Majorana modes based on the quantum anomalous Hall system in proximity to a superconductor.

Visible light-induced radical cascade acylmethylation/cyclization of 2-(allyloxy)arylaldehydes with α-bromo ketones: access to cyclic 1,5-dicarbonyl-containing chroman-4-one skeletons.

A novel photocatalytic protocol for effective and efficient synthesis of cyclic 1,5-diketones containing chroman-4-one skeletons in moderate to good yields via radical cascade acylmethylation/cyclization of 2-(allyloxy)arylaldehydes with α-bromo ketones has been described. This reaction features a broad substrate scope, good functional group tolerance, and metal- and oxidant-free conditions. An acylmethyl radical-triggered cascade cyclization was involved.

α7 nicotinic acetylcholine receptor agonist improved brain injury and impaired glucose metabolism in a rat model of ischemic stroke.

Vagus nerve stimulation through the action of acetylcholine can modulate inflammatory responses and metabolism. α7 Nicotinic Acetylcholine Receptor (α7nAChR) is a key component in the biological functions of acetylcholine. To further explore the health benefits of vagus nerve stimulation, this study aimed to investigate whether α7nAChR agonists offer beneficial effects against poststroke inflammatory and metabolic changes and to identify the underlying mechanisms in a rat model of stroke established by permanent cerebral ischemia. We found evidence showing that pretreatment with α7nAChR agonist, GTS-21, improved poststroke brain infarction size, impaired motor coordination, brain apoptotic caspase 3 activation, dysregulated glucose metabolism, and glutathione reduction. In ischemic cortical tissues and gastrocnemius muscles with GTS-21 pretreatment, macrophages/microglia M1 polarization-associated Tumor Necrosis Factor-α (TNF-α) mRNA, Cluster of Differentiation 68 (CD68) protein, and Inducible Nitric Oxide Synthase (iNOS) protein expression were reduced, while expression of anti-inflammatory cytokine IL-4 mRNA, and levels of M2 polarization-associated CD163 mRNA and protein were increased. In the gastrocnemius muscles, stroke rats showed a reduction in both glutathione content and Akt Serine 473 phosphorylation, as well as an elevation in Insulin Receptor Substrate-1 Serine 307 phosphorylation and Dynamin-Related Protein 1 Serine 616 phosphorylation. GTS-21 reversed poststroke changes in the gastrocnemius muscles. Overall, our findings, provide further evidence supporting the neuroprotective benefits of α7nAChR agonists, and indicate that they may potentially exert anti-inflammatory and metabolic effects peripherally in the skeletal muscle in an acute ischemic stroke animal model.

Helical Luttinger Liquid on the Edge of a Two-Dimensional Topological Antiferromagnet.

A boundary helical Luttinger liquid (HLL) with broken bulk time-reversal symmetry belongs to a unique topological class that may occur in antiferromagnets (AFM). Here, we search for signatures of HLL on the edge of a recently discovered topological AFM, MnBi2Te4 even-layer. Using a scanning superconducting quantum interference device, we directly image helical edge current in the AFM ground state appearing at its charge neutral point. Such a helical edge state accompanies an insulating bulk which is topologically distinct from the ferromagnetic Chern insulator phase, as revealed in a magnetic field driven quantum phase transition. The edge conductance of the AFM order follows a power law as a function of temperature and source-drain bias which serves as strong evidence for HLL. Such HLL scaling is robust at finite fields below the quantum critical point. The observed HLL in a layered AFM semiconductor represents a highly tunable topological matter compatible with future spintronics and quantum computation.

Genome of Hippophae rhamnoides provides insights into a conserved molecular mechanism in actinorhizal and rhizobial symbioses.

Sea buckthorn (Hippophae rhamnoides), a horticulturally multipurpose species in the family Elaeagnaceae, can build associations with Frankia actinomycetes to enable symbiotic nitrogen-fixing. Currently, no high-quality reference genome is available for an actinorhizal plant, which greatly hinders the study of actinorhizal symbiotic nodulation. Here, by combining short-read, long-read and Hi-C sequencing technologies, we generated a chromosome-level reference genome of H. rhamnoides (scaffold N50: 65 Mb, and genome size: 730 Mb) and predicted 30 812 protein-coding genes mainly on 12 pseudochromosomes. Hippophae rhamnoides was found to share a high proportion of symbiotic nodulation genes with Medicago truncatula, implying a shared molecular mechanism between actinorhizal and rhizobial symbioses. Phylogenetic analysis clustered the three paralogous NODULE INCEPTION (NIN) genes of H. rhamnoides with those of other nodulating species, forming the NIN group that most likely evolved from the ancestral NLP group. The genome of H. rhamnoides will help us to decipher the underlying genetic programming of actinorhizal symbiosis, and our high-quality genome and transcriptomic resources will make H. rhamnoides a new excellent model plant for actinorhizal symbiosis research.

Establishing the blood reference interval of pancreatic elastase-1: A prospective study.

BACKGROUND AND AIM: Pancreatic elastase-1 (PE-1) has been investigated in pancreatic disorders. However, the reference interval (RI) of PE-1 in blood remains unconfirmed. We aimed to establish the blood RI of PE-1 in an adult population. METHODS: In this prospective cross-sectional study, we enrolled 400 adults who had received the whole-body physical check-up program between May 1, 2019 and November 20, 2019. The serum and plasma PE-1 levels were measured by latex turbidimetric immunoassay in different storage conditions (fresh, refrigerated, and frozen). The 95% and 99% RI of PE-1 were calculated according to the Clinical & Laboratory Standards Institute guidelines. The correlations between PE-1 and other parameters were analyzed using multivariable regression models. Ultimately, 38 patients with acute pancreatitis were prospectively recruited as the validation cohort. RESULTS: The PE-1 levels in fresh serum were highly correlated with those in refrigerated (R2  = 0.998) or frozen (R2  = 0.942) samples; however, plasma should not be suggested in frozen conditions (plasma vs serum: R2  = 0.185). In the RI study population (202 male & 198 female participants), the median age was 52.6 (25-75% interquartile range: 43.1-61.0). The 95% and 99% RIs of PE-1 were 30.0-221.0 and 22.0-359.0 ng/dL, respectively. Triglycerides (ß = 0.106, P = 0.033), lipase (ß = 0.154, P = 0.007), and CA19-9 (ß = 0.130, P = 0.008) were independent factors associated with PE-1. In the pancreatitis validation cohort, with a cut-off value of 359.0 ng/dL, the sensitivity and specificity were 100% and 99.8%, respectively. CONCLUSION: The RI of PE-1 established in this study can be used for further applications. Serum is the suggested form for frozen sample storage.

The microbial diversity in industrial effluents makes high-throughput sequencing-based source tracking of the effluents possible.

In order to explore the microbial diversity in industrial effluents, and on this basis, to verify the feasibility of tracking industrial effluents in sewer networks based on sequencing data, we collected 28 sewage samples from the industrial effluents relative to four factories in Shenzhen, China, and sequenced the 16S rRNA genes to profile the microbial compositions. We identified 5413 operational taxonomic units (OTUs) in total, and found that microbial compositions were highly diverse among samples from different locations in the sewer system, with only 107 OTUs shared by 90% of the samples. These shared OTUs were enriched in the phylum of Proteobacteria, the families of Comamonadaceae and Pseudomonadaceae, as well as the genus of Pseudomonas, with both degradation related and pathogenic bacteria. More importantly, we found differences in microbial composition among samples relevant to different factories, and identified microbial markers differentiating effluents from these factories, which can be used to track the sources of the effluents. This study improved our understanding of microbial diversity in industrial effluents, proved the feasibility of industrial effluent source tracking based on sequencing data, and provided an alternative technique solution for environmental surveillance and management.

Cyp17a effected by endocrine disruptors and its function in gonadal development of Hyriopsis cumingii.

Estrogens and androgens that coexist in the aquatic environment could potentially affect shellfish, however, endocrine disrupting effects of them in shellfish are significant. As an important aquaculture shellfish in China, Hyriopsis cumingii has remarkable economic benefits. In this study, the effects of endocrine disrupting chemicals on the steroid synthase Hc-Cyp17a in the male and female gonads of the H. cumingii were assessed by exposing juvenile mussels to cultured waters containing 17ß-Estradiol (E2) and 17α-Methyltestosterone (MT) for 28 days. At the same time, the E2 content in the four stages of gonadal development, the expression changes of Hc-Cyp17a in gonadal development and its localization in the mature gonad were measured to explore the relationship between genes and hormones. The results showed that both E2 and MT at 50 ng/L and 200 ng/L could affect the transcription level of Hc-Cyp17a, which was inhibited initially and promoted in post-development. E2 content was positively correlated with gonadal development stage, which was in mussel. By tracing the expression of Hc-Cyp17a, difference was found during different developmental periods. The expression level in ovary was higher than that in testis during gonadal development of 1/ 2/ 3-year-old mussels and showed an increasing trend with age. Furthermore, the expression levels in 6 tissues of mature individuals were measured and it showed that there was a significant difference between male and female in the gonads (p < 0.01). In situ hybridization, it suggested that Hc-Cyp17a was significantly signaled in the follicular wall and oocyte of female and in the follicular membrane of testis, respectively. These results could play a vital role in assessing and understanding the effects of aquatic environment on the endocrine system of H. cumingii.

Intertwined Topological and Magnetic Orders in Atomically Thin Chern Insulator MnBi2Te4.

MnBi2Te4, a van der Waals magnet, is an emergent platform for exploring Chern insulator physics. Its layered antiferromagnetic order was predicted to enable even-odd layer number dependent topological states. Furthermore, it becomes a Chern insulator when all spins are aligned by an applied magnetic field. However, the evolution of the bulk electronic structure as the magnetic state is continuously tuned and its dependence on layer number remains unexplored. Here, employing multimodal probes, we establish one-to-one correspondence between bulk electronic structure, magnetic state, topological order, and layer thickness in atomically thin MnBi2Te4 devices. As the magnetic state is tuned through the canted magnetic phase, we observe a band crossing, i.e., the closing and reopening of the bulk band gap, corresponding to the concurrent topological phase transition in both even- and odd-layer-number devices. Our findings shed new light on the interplay between band topology and magnetic order in this newly discovered topological magnet.

The Origin of Additive Genetic Variance Driven by Positive Selection.

Fisher's fundamental theorem of natural selection predicts no additive variance of fitness in a natural population. Consistently, studies in a variety of wild populations show virtually no narrow-sense heritability (h2) for traits important to fitness. However, counterexamples are occasionally reported, calling for a deeper understanding on the evolution of additive variance. In this study, we propose adaptive divergence followed by population admixture as a source of the additive genetic variance of evolutionarily important traits. We experimentally tested the hypothesis by examining a panel of ∼1,000 yeast segregants produced by a hybrid of two yeast strains that experienced adaptive divergence. We measured >400 yeast cell morphological traits and found a strong positive correlation between h2 and evolutionary importance. Because adaptive divergence followed by population admixture could happen constantly, particularly in species with wide geographic distribution and strong migratory capacity (e.g., humans), the finding reconciles the observation of abundant additive variances in evolutionarily important traits with Fisher's fundamental theorem of natural selection. Importantly, the revealed role of positive selection in promoting rather than depleting additive variance suggests a simple explanation for why additive genetic variance can be dominant in a population despite the ubiquitous between-gene epistasis observed in functional assays.

Robust axion insulator and Chern insulator phases in a two-dimensional antiferromagnetic topological insulator.

The intricate interplay between non-trivial topology and magnetism in two-dimensional materials can lead to the emergence of interesting phenomena such as the quantum anomalous Hall effect. Here we investigate the quantum transport of both bulk crystal and exfoliated MnBi2Te4 flakes in a field-effect transistor geometry. For the six septuple-layer device tuned into the insulating regime, we observe a large longitudinal resistance and zero Hall plateau, which are characteristics of an axion insulator state. The robust axion insulator state occurs in zero magnetic field, over a wide magnetic-field range and at relatively high temperatures. Moreover, a moderate magnetic field drives a quantum phase transition from the axion insulator phase to a Chern insulator phase with zero longitudinal resistance and quantized Hall resistance h/e2, where h is Planck's constant and e is electron charge. Our results pave the way for using even-number septuple-layer MnBi2Te4 to realize the quantized topological magnetoelectric effect and axion electrodynamics in condensed matter systems.

DHA attenuated Japanese Encephalitis virus infection-induced neuroinflammation and neuronal cell death in cultured rat Neuron/glia.

Japanese Encephalitis Virus (JEV) is a neurotropic virus and its Central Nervous System (CNS) infection causes fatal encephalitis with high mortality and morbidity. Microglial activation and consequences of bystander damage appear to be the dominant mechanisms for Japanese Encephalitis and complications. Docosahexaenoic acid (DHA), an essential fatty acid and a major component of brain cell membranes, possesses additional biological activities, including anti-apoptosis, anti-inflammation, and neuroprotection. Through this study, we have provided experimental evidence showing the anti-inflammatory, neuroprotective, and anti-viral effects of DHA against JEV infection in rat Neuron/glia cultures. By Neuron/glia and Neuron cultures, DHA protected against neuronal cell death upon JEV infection and reduced JEV amplification. In Neuron/glia and Microglia cultures, the effects of DHA were accompanied by the downregulation of pro-inflammatory M1 microglia, upregulation of anti-inflammatory M2 microglia, and reduction of neurotoxic cytokine expression, which could be attributed to its interference in the Toll-Like Receptor (TLR), Mitogen-Activated Protein Kinase (MAPK), and Interferon/Janus Kinase/Signal Transducers and Activators of Transcription (Stat), along with the NF-κB, AP-1, and c-AMP Response Element Binding Protein (CREB) controlled transcriptional programs. Parallel anti-inflammatory effects against JEV infection were duplicated by G Protein-Coupled Receptor (GPR120) and GPR40 agonists and a reversal of DHA-mediated anti-inflammation was seen in the presence of GPR120 antagonist, while the GPR40 was less effectiveness. Since increasing evidence indicates its neuroprotection against neurodegenerative diseases, DHA is a proposed anti-inflammatory and neuroprotective candidate for the treatment of neuroinflammation-accompanied viral pathogenesis such as Japanese Encephalitis.

Identification of wnt2 in the pearl mussel Hyriopsis cumingii and its role in innate immunity and gonadal development.

Wnt2 is a significant factor in the Wnt signaling pathway, which is associated with a variety of physiological activities, including inflammatory response, cell apoptosis, reproductive system development, and cell differentiation. Hyriopsis cumingii is the main pearl breeding mussel in China. However, the role of wnt2 in this species remains unclear. In this study, wnt2 from H. cumingii was cloned and identified. The full-length cDNA of wnt2 is 1524 bp, containing a 963 bp open reading frame (ORF), encoding 320 amino acid residues. The tissue distribution of H. cumingii indicated that wnt2 was predominantly highly expressed in the ovary and gill. And the expression profile after Aeromonas hydrophila or LPS injection indicated that wnt2 was up-regulated in gill, suggesting its role in the innate immune response. The expression of wnt2 was high at 4-month-old of early gonadal development and throughout ovarian development. In situ hybridization (ISH) showed significant hybridization signals on the gills and mature eggs of female gonads. In addition, miR-1988b-5p was found to negatively regulate wnt2 to affect the expression of key genes (frizzled-5, ctnnb1, and tcf7l) in the Wnt signaling pathway. Thus, these findings suggest a key role for wnt2 in immune regulation and gonadal development in H. cumingii.

Electronic States and Magnetic Response of MnBi2Te4 by Scanning Tunneling Microscopy and Spectroscopy.

Exotic quantum phenomena have been demonstrated in recently discovered intrinsic magnetic topological insulator MnBi2Te4. At its two-dimensional limit, the quantum anomalous Hall effect and axion insulator state were observed in odd and even layers of MnBi2Te4, respectively. Here, we employ low-temperature scanning tunneling microscopy to study the electronic properties of MnBi2Te4. The quasiparticle interference patterns indicate that the electronic structures on the topmost layer of MnBi2Te4 are different from those of the expected out-of-plane A-type antiferromagnetic phase. The topological surface states may be embedded in deeper layers beneath the topmost surface. Such novel electronic structure is presumably related to the modification of crystalline structure during sample cleaving and reorientation of the magnetic moment of Mn atoms near the surface. Mn dopants substituted at the Bi site on the second atomic layer are observed. The electronic structures fluctuate at atomic scale on the surface, which can affect the magnetism of MnBi2Te4.

Effect of Structural Supermodulation on Superconductivity in Trilayer Cuprate Bi_{2}Sr_{2}Ca_{2}Cu_{3}O_{10+δ}.

We investigate the spatial and doping evolutions of the superconducting properties of trilayer cuprate Bi_{2}Sr_{2}Ca_{2}Cu_{3}O_{10+δ} by using scanning tunneling microscopy and spectroscopy. Both the superconducting coherence peak and gap size exhibit periodic variations with structural supermodulation, but the effect is much more pronounced in the underdoped regime than at optimal doping. Moreover, a new type of tunneling spectrum characterized by two superconducting gaps emerges with increasing doping, and the two-gap features also correlate with the supermodulation. We propose that the interaction between the inequivalent outer and inner CuO_{2} planes is responsible for these novel features that are unique to trilayer cuprates.