Selective and quasi-continuous switching of ferroelectric Chern insulator devices for neuromorphic computing.

Quantum materials exhibit dissipationless topological edge state transport with quantized Hall conductance, offering notable potential for fault-tolerant computing technologies. However, the development of topological edge state-based computing devices remains a challenge. Here we report the selective and quasi-continuous ferroelectric switching of topological Chern insulator devices, showcasing a proof-of-concept demonstration in noise-immune neuromorphic computing. We fabricate this ferroelectric Chern insulator device by encapsulating magic-angle twisted bilayer graphene with doubly aligned h-BN layers and observe the coexistence of the interfacial ferroelectricity and the topological Chern insulating states. The observed ferroelectricity exhibits an anisotropic dependence on the in-plane magnetic field. By tuning the amplitude of the gate voltage pulses, we achieve ferroelectric switching between any pair of Chern insulating states in the presence of a finite magnetic field, resulting in 1,280 ferroelectric states with distinguishable Hall resistance levels on a single device. Furthermore, we demonstrate deterministic switching between two arbitrary levels among the record-high number of ferroelectric states. This unique switching capability enables the implementation of a convolutional neural network resistant to external noise, utilizing the quantized Hall conductance levels of the Chern insulator device as weights. Our study provides a promising avenue towards the development of topological quantum neuromorphic computing, where functionality and performance can be drastically enhanced by topological quantum materials.

Quantum spin liquid signatures in monolayer 1T-NbSe2.

Quantum spin liquids (QSLs) are in a quantum disordered state that is highly entangled and has fractional excitations. As a highly sought-after state of matter, QSLs were predicted to host spinon excitations and to arise in frustrated spin systems with large quantum fluctuations. Here we report on the experimental observation and theoretical modeling of QSL signatures in monolayer 1T-NbSe2, which is a newly emerging two-dimensional material that exhibits both charge-density-wave (CDW) and correlated insulating behaviors. By using scanning tunneling microscopy and spectroscopy (STM/STS), we confirm the presence of spin fluctuations in monolayer 1T-NbSe2 by observing the Kondo resonance as monolayer 1T-NbSe2 interacts with metallic monolayer 1H-NbSe2. Subsequent STM/STS imaging of monolayer 1T-NbSe2 at the Hubbard band energy further reveals a long-wavelength charge modulation, in agreement with the spinon modulation expected for QSLs. By depositing manganese-phthalocyanine (MnPc) molecules with spin S = 3/2 onto monolayer 1T-NbSe2, new STS resonance peaks emerge at the Hubbard band edges of monolayer 1T-NbSe2. This observation is consistent with the spinon Kondo effect induced by a S = 3/2 magnetic impurity embedded in a QSL. Taken together, these experimental observations indicate that monolayer 1T-NbSe2 is a new promising QSL material.

Effect of Multidirectional Forging and Aging Treatment on Wear Properties of ZK61 Alloy.

This study investigated the effects of multidirectional forging (MDF) and aging treatments on the wear properties of ZK61 magnesium alloy. Dry sliding wear tests were performed on homogenized, MDF, and aged samples using a friction wear machine to analyze the surface morphology by scanning electron microscopy (SEM) and white light interferometry, as well as the hardness and tensile mechanical properties. The ZK61 magnesium alloy has higher sliding wear properties after MDF due to higher strength, hardness, and work hardening. Grain refinement affects the wear resistance of the material, but aging increases the hardness and tensile strength and decreases the wear resistance.

Preparation of Acrylic Yarns with Durable Structural Colors Based on Stable Photonic Crystals.

Structural coloration of photonic crystals (PCs) is considered an ecological and environmental way to achieve colorful textiles. However, constructing PCs with obvious structural colors on traditional flexible yarns is still a great challenge. As a secondary structure that forms textiles, compared with fibers and fabrics, the yarns are rougher, hindering the construction of regular PCs. In this work, the flexible acrylic yarns with vivid structural colors, named PC-based structural color yarns, were prepared by constructing regular PCs via assembling poly(styrene-butyl acrylate-methacrylate) (P(St-BA-MAA)) colloidal microspheres on yarns. Specifically, the properties of P(St-BA-MAA) colloidal microspheres were investigated. The PCs with better structural stability and obvious structural colors were prepared by presetting the acrylic adhesive layer on yarns. Moreover, the color durability and color regulation methods of prepared PC-based structural color yarns were evaluated and discussed. The results showed that the P(St-BA-MAA) colloidal microspheres exhibited even particle sizes, excellent monodispersity, and a typical hard core-soft shell structure. And the glass-transition temperature (T g) of the microspheres was tested to be about 65.6 °C. The cationic acrylate regarded as a pretreatment agent could not only improve the combination between the PC layers and the yarns by acting as a "bridge" but also enhance the structural color effect by smoothing the yarn surface. The results showed that when the mass fraction of cationic acrylate was 3 wt %, the microspheres were beneficial to access regular PCs with obvious structural colors. The PCs with bright structural colors could be constructed on black acrylic yarns, and the colors of yarns were still bright after rubbing and washing tests, indicating that the prepared PC-based structural color yarns have good color fastness. Moreover, the color hue of PC-based structural color yarns could be regulated by adjusting the particle sizes and viewing angles. This study provides strategic support for the structural coloration of flexible materials.

MicroRNA-21 electrochemiluminescence biosensor based on Co-MOF-N-(4-aminobutyl)-N-ethylisoluminol/Ti3C2Tx composite and duplex-specific nuclease-assisted signal amplification.

A novel electrochemiluminescence (ECL) biosensor for the determination of microRNA-21 (miRNA-21) was developed, based on a hybrid luminescent Co-MOF-ABEI/Ti3C2Tx composite as an ECL luminophore combined with a duplex-specific nuclease (DSN)-assisted signal amplification strategy. The synthesized Co-MOF-ABEI/Ti3C2Tx composite carrying N-(4-aminobutyl)-N-ethylisoluminol (ABEI) exhibited strong and stable ECL in the presence of reactive oxygen species (ROS). The ECL biosensor was fabricated by adsorbing Co-MOF-ABEI/Ti3C2Tx onto a glassy carbon electrode and covalently coupling the probe DNA onto the surface of the Co-MOF-ABEI/Ti3C2Tx-modified electrode. In the presence of the target miRNA-21, the DSN selectively cleaved the complementary DNA section (S1) to miRNA-21, resulting in the release of the transduction section (S2) and the reuse of miRNA-21 in the subsequent amplification cycle. The interaction of the stem-loop structure of the probe DNA with the Co-MOF-ABEI/Ti3C2Tx-modified glassy carbon electrode with S2 strands led to the opening of the annular part of the probe DNA. Then, the opened guanine (G)-rich sequences of probe DNA were exposed and folded into a hemin/G-quadruplex DNAzyme in the presence of hemin. The catalysis of H2O2 to ROS by the hemin/G-quadruplex DNAzyme significantly enhanced ECL intensity, and this intensity was logarithmically proportional to the concentration of target miRNA-21 between 0.00001 and 10 nM, having a limit of detection of 3.7 fM. The designed ECL biosensor can  detect miRNA-21 extracted from HeLa cells, indicating its promising application in clinical diagnosis and disease prognosis analysis.

The platelet-lymphocyte ratio is a promising predictor of early postoperative acute kidney injury following cardiac surgery: a case-control study.

BACKGROUND: Acute kidney injury (AKI) is a common complication following cardiac surgery. This study explored the correlation between hematological biomarkers and the occurrence of postoperative AKI following cardiac surgery. METHODS: This was a retrospective case-control, single-center study. This study enrolled 91 patients who underwent cardiac surgery with cardiopulmonary bypass (CPB) support in Guangdong Provincial People's Hospital Zhuhai Hospital between March 2019 and July 2021. The baseline serum creatinine levels of the patients was <132.6 µmol/L. The patients' electronic medical records were retrospectively reviewed. AKI was diagnosed according to the Kidney Disease Improving Global Outcomes (KDIGO) 2012 Acute Kidney Injury Guideline criteria. Patients who sustained AKI in the 48 hours following cardiac surgery were categorized as Group A (n=48), while patients with normal serum creatinine levels postoperatively were categorized as Group B (n=43). The baseline demographic and clinical characteristics of the two groups were compared. Univariate analysis was performed to evaluate the correlation between biomarkers and postoperative AKI. Multivariate logistic regression was performed to identify the predictors of AKI following cardiac surgery. RESULTS: Forty-eight patients were diagnosed with AKI during the first 48 hours after cardiac surgery, while 43 patients were found to have normal creatinine levels postoperatively. Multivariate logistic regression analysis revealed advanced age (P=0.007), preoperative increased creatinine (P=0.023), duration of intraoperative hypotension (P=0.027), and the platelet-lymphocyte ratio (P/LR; P=0.042) as predictors of AKI following cardiac surgery with CPB. This study was performed in a single center, which might not be generalized to whole population. Ongoing review and modification of the surgical protocols may contribute to bias of the study. CONCLUSIONS: The P/LR can be obtained from a routine blood test, and may potentially be utilized as an independent indicator of AKI following cardiac surgery.

Giant orbital magnetoelectric effect and current-induced magnetization switching in twisted bilayer graphene.

Recently, quantum anomalous Hall effect with spontaneous ferromagnetism was observed in twisted bilayer graphenes (TBG) near 3/4 filling. Importantly, it was observed that an extremely small current can switch the direction of the magnetization. This offers the prospect of realizing low energy dissipation magnetic memories. However, the mechanism of the current-driven magnetization switching is poorly understood as the charge currents in graphenes are generally believed to be non-magnetic. In this work, we demonstrate that in TBG, the twisting and substrate induced symmetry breaking allow an out of plane orbital magnetization to be generated by a charge current. Moreover, the large Berry curvatures of the flat bands give the Bloch electrons large orbital magnetic moments so that a small current can generate a large orbital magnetization. We further demonstrate how the charge current can switch the magnetization of the ferromagnetic TBG near 3/4 filling as observed in the experiments.

Grouting Quality Evaluation in Post-Tensioning Tendon Ducts Using Wavelet Packet Transform and Bayes Classifier.

The grouting quality of tendon ducts is very important for post-tensioning technology in order to protect the prestressing reinforcement from environmental corrosion and to make a smooth stress distribution. Unfortunately, various grouting defects occur in practice, and there is no efficient method to evaluate grouting compactness yet. In this study, a method based on wavelet packet transform (WPT) and Bayes classifier was proposed to evaluate grouting conditions using stress waves generated and received by piezoelectric transducers. Six typical grouting conditions with both partial grouting and cavity defects of different dimensions were experimentally investigated. The WPT was applied to explore the energy of received stress waves at multi-scales. After that, the Bayes classifier was employed to identify the grouting conditions, by taking the traditionally used total energy and the proposed energy vector of WPT components as input, respectively. The experimental results demonstrated that the Bayes classifier input with the energy vector could identify different grouting conditions more accurately. The proposed method has the potential to be applied at key spots of post-tensioning tendon ducts in practice.

Transport evidence of asymmetric spin-orbit coupling in few-layer superconducting 1Td-MoTe2.

Two-dimensional transition metal dichalcogenides MX2 (M = W, Mo, Nb, and X = Te, Se, S) with strong spin-orbit coupling possess plenty of novel physics including superconductivity. Due to the Ising spin-orbit coupling, monolayer NbSe2 and gated MoS2 of 2H structure can realize the Ising superconductivity, which manifests itself with in-plane upper critical field far exceeding Pauli paramagnetic limit. Surprisingly, we find that a few-layer 1Td structure MoTe2 also exhibits an in-plane upper critical field which goes beyond the Pauli paramagnetic limit. Importantly, the in-plane upper critical field shows an emergent two-fold symmetry which is different from the isotropic in-plane upper critical field in 2H transition metal dichalcogenides. We show that this is a result of an asymmetric spin-orbit coupling in 1Td transition metal dichalcogenides. Our work provides transport evidence of a new type of asymmetric spin-orbit coupling in transition metal dichalcogenides which may give rise to novel superconducting and spin transport properties.

Spinon Fermi Surface in a Cluster Mott Insulator Model on a Triangular Lattice and Possible Application to 1T-TaS_{2}.

1T-TaS_{2} is a cluster Mott insulator on the triangular lattice with 13 Ta atoms forming a star of David cluster as the unit cell. We derive a two-dimensional XXZ spin-1/2 model with a four-spin ring exchange term to describe the effective low energy physics of a monolayer 1T-TaS_{2}, where the effective spin-1/2 degrees of freedom arises from the Kramers degenerate spin-orbital states on each star of David. A large scale density matrix renormalization group simulation is further performed on this effective model and we find a gapless spin liquid phase with a spinon Fermi surface at a moderate to large strength region of the four-spin ring exchange term. All peaks in the static spin structure factor are found to be located on the "2k_{F}" surface of a half-filled spinon on the triangular lattice. Experiments to detect the spinon Fermi surface phase in 1T-TaS_{2} are discussed.

Aberrant expression of miR-153 is associated with the poor prognosis of cervical cancer.

Previous studies have demonstrated that microRNAs (miRNAs) are frequently dysregulated in tumors and are associated with the initiation and progression of various types of cancer. miR-153 has been previously shown to have an anti-tumor effect in the majority of cancer types. However, to date, the expression status and function of miR-153 in cervical cancer (CC) remains unclear. In the present study, the expression of miR-153 in CC tissues and cell lines was examined, revealing that the expression of miR-153 was markedly downregulated in the CC tissues and cell lines investigated, when compared with matched noncancerous tissues and normal cervical epithelial cell line. Furthermore, ectopic expression of miR-153 by miR-153 mimic inhibited cell proliferation; however, transfection with the miR-153 inhibitor promoted the cell proliferation in CC cell lines. Finally, the results showed that the downregulation of miR-153 was associated with poor 5-year over survival in CC patients and it could be regarded as an independent biomarker to predict the prognosis of CC patients. Collectively, these results indicated that miR-153 may function as a tumor suppressor in CC, and it may be a potential novel therapeutic target for CC.

An unusual continuous paramagnetic-limited superconducting phase transition in 2D NbSe 2.

Time reversal and spatial inversion are two key symmetries for conventional Bardeen-Cooper-Schrieffer (BCS) superconductivity 1 . Breaking inversion symmetry can lead to mixed-parity Cooper pairing and unconventional superconducting properties1-5. Two-dimensional (2D) NbSe2 has emerged as a new non-centrosymmetric superconductor with the unique out-of-plane or Ising spin-orbit coupling (SOC)6-9. Here we report the observation of an unusual continuous paramagnetic-limited superconductor-normal metal transition in 2D NbSe2. Using tunelling spectroscopy under high in-plane magnetic fields, we observe a continuous closing of the superconducting gap at the upper critical field at low temperatures, in stark contrast to the abrupt first-order transition observed in BCS thin-film superconductors10-12. The paramagnetic-limited continuous transition arises from a large spin susceptibility of the superconducting phase due to the Ising SOC. The result is further supported by self-consistent mean-field calculations based on the ab initio band structure of 2D NbSe2. Our findings establish 2D NbSe2 as a promising platform to explore novel spin-dependent superconducting phenomena and device concepts 1 , such as equal-spin Andreev reflection 13 and topological superconductivity14-16.

The emergence of Dirac points in photonic crystals with mirror symmetry.

We show that Dirac points can emerge in photonic crystals possessing mirror symmetry when band gap closes. The mechanism of generating Dirac points is discussed in a two-dimensional photonic square lattice, in which four Dirac points split out naturally after the touching of two bands with different parity. The emergence of such nodal points, characterized by vortex structure in momentum space, is attributed to the unavoidable band crossing protected by mirror symmetry. The Dirac nodes can be unbuckled through breaking the mirror symmetry and a photonic analog of Chern insulator can be achieved through time reversal symmetry breaking. Breaking time reversal symmetry can lead to unidirectional helical edge states and breaking mirror symmetry can reduce the band gap to amplify the finite size effect, providing ways to engineer helical edge states.

Chiral tunneling in a twisted graphene bilayer.

The perfect transmission in a graphene monolayer and the perfect reflection in a Bernal graphene bilayer for electrons incident in the normal direction of a potential barrier are viewed as two incarnations of the Klein paradox. Here we show a new and unique incarnation of the Klein paradox. Owing to the different chiralities of the quasiparticles involved, the chiral fermions in a twisted graphene bilayer show an adjustable probability of chiral tunneling for normal incidence: they can be changed from perfect tunneling to partial or perfect reflection, or vice versa, by controlling either the height of the barrier or the incident energy. As well as addressing basic physics about how the chiral fermions with different chiralities tunnel through a barrier, our results provide a facile route to tune the electronic properties of the twisted graphene bilayer.

Strain and curvature induced evolution of electronic band structures in twisted graphene bilayer.

It is well established that strain and geometry could affect the band structure of graphene monolayer dramatically. Here we study the evolution of local electronic properties of a twisted graphene bilayer induced by a strain and a high curvature, which are found to strongly affect the local band structures of the twisted graphene bilayer. The energy difference of the two low-energy van Hove singularities decreases with increasing lattice deformation and the states condensed into well-defined pseudo-Landau levels, which mimic the quantization of massive chiral fermions in a magnetic field of about 100 T, along a graphene wrinkle. The joint effect of strain and out-of-plane distortion in the graphene wrinkle also results in a valley polarization with a significant gap. These results suggest that strained graphene bilayer could be an ideal platform to realize the high-temperature zero-field quantum valley Hall effect.