Search

Intrinsic magnetic topological insulators have emerged as a promising platform to study the interplay between the topological surface states and ferromagnetism. This unique interplay can give rise to a variety of exotic quantum phenomena, including the quantum anomalous Hall effect and axion insulating states. Here, utilizing molecular beam epitaxy (MBE), we present a comprehensive study of the growth of MnBi2Te4 thin films on Si (111), epitaxial graphene, and highly ordered pyrolytic graphite substrates. By combining a suite of in situ characterization techniques, we obtain critical insights into the nanoscale control of MnBi2Te4 epitaxial growth. First, we extract the free energy landscape for the epitaxial relationship as a function of the in-plane angular distribution. Then, by employing an optimized layer-by-layer growth, we determine the chemical potential and Dirac point of the thin film at different thicknesses and how this quantity is manifested by the dopant compensation from different antisite defects. Overall, these results establish a foundation for understanding the growth kinetics of MnBi2Te4 and pave the way for future applications of MBE-grown thin films in emerging topological quantum materials. [ABSTRACT FROM AUTHOR]

Electrical stimulation (ES) is proposed as a therapeutic solution for managing chronic wounds. However, its widespread clinical adoption is limited by the requirement of additional extracorporeal devices to power ES‐based wound dressings. In this study, a novel sandwich‐structured photovoltaic microcurrent hydrogel dressing (PMH dressing) is designed for treating diabetic wounds. This innovative dressing comprises flexible organic photovoltaic (OPV) cells, a flexible micro–electro–mechanical systems (MEMS) electrode, and a multifunctional hydrogel serving as an electrode–tissue interface. The PMH dressing is engineered to administer ES, mimicking the physiological injury current occurring naturally in wounds when exposed to light; thus, facilitating wound healing. In vitro experiments are performed to validate the PMH dressing's exceptional biocompatibility and robust antibacterial properties. In vivo experiments and proteomic analysis reveal that the proposed PMH dressing significantly accelerates the healing of infected diabetic wounds by enhancing extracellular matrix regeneration, eliminating bacteria, regulating inflammatory responses, and modulating vascular functions. Therefore, the PMH dressing is a potent, versatile, and effective solution for diabetic wound care, paving the way for advancements in wireless ES wound dressings. [ABSTRACT FROM AUTHOR]

Objective To explore the feasibility of using marking and fusion image-guided technique with cone-beam CT (CBCT) in cases of kidney ruptured haemorrhage without extravascular leakage in digital subtraction angiography (DSA) images. Methods This is a retrospective case-control study that included 43 patients who underwent transcatheter arterial embolization for kidney ruptured haemorrhage and difficult haemostasis. The patients were divided into two groups: the CBCT group (cases without extravascular leakage observed in angiography) and the control group (cases with clearly identifiable target vessels in angiography). The baseline characteristics and clinical outcomes were collected and analysed. Results The results showed no statistically significant differences in the duration of the procedure and intraoperative blood transfusion between the control and CBCT groups (P  >  .05). The study clarified that the CBCT group had a significantly higher rate of improvement of gross haematuria compared to the control group (P  < .05). The CBCT group showed a greater increase in haemoglobin and a lesser increase in creatinine. The clinical success rates were 87.5% in the control group and 90.9% in the CBCT group (P  >  .05). Conclusions The marking and fusion image-guided technique is useful in cases of kidney ruptured haemorrhage without extravascular leakage of contrast agent. The technique is safe, feasible, and effective, and we believe it is superior to purely DSA-guidance. Advances in knowledge The use of the marking and fusion image-guided technique is recommended to overcome the challenge of undetectable target vessels during interventional procedures. This technique is considered as non-inferior to purely DSA-guided interventional procedures where the target vessels are clearly identifiable. [ABSTRACT FROM AUTHOR]

An axion insulator is a three-dimensional (3D) topological insulator (TI), in which the bulk maintains the time-reversal symmetry or inversion symmetry but the surface states are gapped by surface magnetization. The axion insulator state has been observed in molecular beam epitaxy (MBE)-grown magnetically doped TI sandwiches and exfoliated intrinsic magnetic TI MnBi2Te4 flakes with an even number layer. All these samples have a thickness of ~ 10 nm, near the 2D-to-3D boundary. The coupling between the top and bottom surface states in thin samples may hinder the observation of quantized topological magnetoelectric response. Here, we employ MBE to synthesize magnetic TI sandwich heterostructures and find that the axion insulator state persists in a 3D sample with a thickness of ~ 106 nm. Our transport results show that the axion insulator state starts to emerge when the thickness of the middle undoped TI layer is greater than ~ 3 nm. The 3D hundred-nanometer-thick axion insulator provides a promising platform for the exploration of the topological magnetoelectric effect and other emergent magnetic topological states, such as the high-order TI phase. A zero Hall conductance plateau has been taken as evidence of the axion insulator state in magnetically doped topological insulator heterostructures, but it can also originate from surface state hybridization. Here the authors establish such a state in a ~106 nm thick sample, where hybridization is negligible. [ABSTRACT FROM AUTHOR]

Over the last decade, the possibility of realizing topological superconductivity (TSC) has generated much excitement. TSC can be created in electronic systems where the topological and superconducting orders coexist, motivating the continued exploration of candidate material platforms to this end. Here, we use molecular beam epitaxy (MBE) to synthesize heterostructures that host emergent interfacial superconductivity when a non-superconducting antiferromagnet (FeTe) is interfaced with a topological insulator (TI) (Bi, Sb)2Te3. By performing in-vacuo angle-resolved photoemission spectroscopy (ARPES) and ex-situ electrical transport measurements, we find that the superconducting transition temperature and the upper critical magnetic field are suppressed when the chemical potential approaches the Dirac point. We provide evidence to show that the observed interfacial superconductivity and its chemical potential dependence is the result of the competition between the Ruderman-Kittel-Kasuya-Yosida-type ferromagnetic coupling mediated by Dirac surface states and antiferromagnetic exchange couplings that generate the bicollinear antiferromagnetic order in the FeTe layer. The authors study (Bi,Sb)2Te3/FeTe bilayers, which feature emergent superconductivity at the interface with Tc ~ 12 K. Through angle-resolved photoemission spectroscopy and electrical transport measurements, they argue that the Dirac-fermion-mediated Ruderman-Kittel-Kasuya-Yosida-type interaction weakens antiferromagnetic order in FeTe layer, allowing for superconductivity. [ABSTRACT FROM AUTHOR]

In order to reveal the influence of spatial non-uniform distribution effect of carbon nanotubes on micro-scale mechanical and electrical properties of carbon nanotube reinforced composites, the fast Fourier transform (FFT) method was used to establish FFT micro-scale mechanical-electrical coupling model. Compared with the experimental data and theoretical calculation results in the literature, the efficiency, accuracy and applicability of the model were verified. The effects of spatial non-uniform distribution of bending and orientation of one-dimensional nano-conductive fillers (1D-NCF) on the mechanical and electrical properties of composites were investigated. The results show that when the volume fraction of 1D-NCF is ≤2%, equivalent conductivity decreases first and then increases with the increase of 1DNCF agglomeration rate, and increases with the increase of maximum orientation angle. When the volume fraction of 1DNCF is ≥3%, saturated equivalent conductivity decreases with the increase of agglomeration rate and maximum orientation angle. The study provides a reference for optimal design and construction of fiber-based flexible mechanical sensing materials. [ABSTRACT FROM AUTHOR]

Background: Ultrasound (US)-guided-only insertion at the bedside is safe and improves the success rates of peripherally inserted central catheter (PICC). However, PICC insertion procedures remain challenging for special cases. Purpose: To show that fluoroscopically guided tip repositioning, for failed US-guided PICC placement, safely led to satisfactory positioning in difficult cases and, importantly, improved success rates of PICC placements. Material and Methods: A retrospective study of 1560 patients who underwent US-guided PICC placement were performed. Patients who failed US-guided PICC placement were transferred to the interventional radiology department for fluoroscopically guided tip repositioning. Baseline characteristics as well as insertion-related factors were collected. All data were analyzed using SPSS software. Results: In total, 37 (2.4%) patients who failed US-guided PICC placement accepted fluoroscopically guided adjustment or re-insertion. Of these 37 patients, 32 were enrolled. We observed no significant differences between right and left arm PICC access (P > 0.05), even though a higher percentage of PICCs were inserted into left arms (56.3%). The basilic vein (65.6%) was the most common insertion site. Only four patients experienced slight angiospasm (3.1%) and venous thrombosis (9.4%). US-guided PICC insertion failures were primarily due to line tip malposition (84.4%). All patients successfully underwent fluoroscopically guided tip repositioning, which resulted in optimal catheter tip positioning. PICC lines were adjusted in most patients (n=28, 87.5%) Conclusion: Malposition was the primary issue causing US-guided PICC insertion failure. Fluoroscopically guided tip repositioning safely and efficaciously led to satisfactory positioning in difficult cases; thus, we recommend this method for patients failing US-guided PICC placement. [ABSTRACT FROM AUTHOR]

Macrophages are highly heterogeneous and exhibit a diversity of functions and phenotypes. They can be divided into pro‐inflammatory macrophages (M1) and anti‐inflammatory macrophages (M2). Diabetic wounds are characterized by a prolonged inflammatory phase and difficulty in healing due to the accumulation of pro‐inflammatory (M1) macrophages in the wound. Therefore, hydrogel dressings with macrophage heterogeneity regulation function hold great promise in promoting diabetic wound healing in clinical applications. However, the precise conversion of pro‐inflammatory M1 to anti‐inflammatory M2 macrophages by simple and biosafe approaches is still a great challenge. Here, an all‐natural hydrogel with the ability to regulate macrophage heterogeneity is developed to promote angiogenesis and diabetic wound healing. The protocatechuic aldehyde hybridized collagen‐based all‐natural hydrogel exhibits good bioadhesive and antibacterial properties as well as reactive oxygen species scavenging ability. More importantly, the hydrogel is able to convert M1 macrophages into M2 macrophages without the need for any additional ingredients or external intervention. This simple and safe immunomodulatory approach shows great application potential for shortening the inflammatory phase of diabetic wound repair and accelerating wound healing. [ABSTRACT FROM AUTHOR]

One-dimensional chiral interface channels can be created at the boundary of two quantum anomalous Hall (QAH) insulators with different Chern numbers. Such a QAH junction may function as a chiral edge current distributer at zero magnetic field, but its realization remains challenging. Here, by employing an in-situ mechanical mask, we use molecular beam epitaxy to synthesize QAH insulator junctions, in which two QAH insulators with different Chern numbers are connected along a one-dimensional junction. For the junction between Chern numbers of 1 and −1, we observe quantized transport and demonstrate the appearance of the two parallel propagating chiral interface channels along the magnetic domain wall at zero magnetic field. For the junction between Chern numbers of 1 and 2, our quantized transport shows that a single chiral interface channel appears at the interface. Our work lays the foundation for the development of QAH insulator-based electronic and spintronic devices and topological chiral networks. Quantum anomalous Hall junctions show great promise for advancing next-generation electronic circuits. Here, the authors demonstrate a scalable method for synthesizing heterostructures of magnetic topological insulators with regions of distinct Chern numbers and characterize the chiral interface modes that emerge at the interface. [ABSTRACT FROM AUTHOR]

Aiming at the problem that the insufficient extraction of feature points in existing forgery detection methods leads to low accuracy of forgery detection and poor recognition rate of feature points descriptor, a color image copy-move forgery detection algorithm based on color moment region division and quaternion Hu moment is proposed. Firstly, an adaptive morphological reconstruction algorithm is adopted to perform superpixel segmentation on the image, and then a density clustering algorithm is used to adaptively divide the image into regions. Secondly, a key point extraction method is proposed to obtain uniform SIFT feature points, and then a local Gaussian pyramid is constructed in a novel color image quaternion representation method to extract the Hu moment features. Finally, after matching features using the 2NN, the paper proposes to locate the copy-move forgery region by the Delaunay triangle algorithm. Experimental results on public datasets show that this method can effectively locate the forgery region. [ABSTRACT FROM AUTHOR]

Polarized neutron reflectometry is a powerful technique to interrogate the structures of multilayered magnetic materials with depth sensitivity and nanometer resolution. However, reflectometry profiles often inhabit a complicated objective function landscape using traditional fitting methods, posing a significant challenge for parameter retrieval. In this work, we develop a data-driven framework to recover the sample parameters from polarized neutron reflectometry data with minimal user intervention. We train a variational autoencoder to map reflectometry profiles with moderate experimental noise to an interpretable, low-dimensional space from which sample parameters can be extracted with high resolution. We apply our method to recover the scattering length density profiles of the topological insulator–ferromagnetic insulator heterostructure Bi2Se3/EuS exhibiting proximity magnetism in good agreement with the results of conventional fitting. We further analyze a more challenging reflectometry profile of the topological insulator–antiferromagnet heterostructure (Bi,Sb)2Te3/Cr2O3 and identify possible interfacial proximity magnetism in this material. We anticipate that the framework developed here can be applied to resolve hidden interfacial phenomena in a broad range of layered systems. [ABSTRACT FROM AUTHOR]

Interplay between the topological properties and electron correlations in quantum materials can induce exotic phenomena. In this study, we grew the 1T-ZrTe2 monolayers on the bilayer graphene/SiC substrate by using molecular beam epitaxy. Through scanning tunneling microscopy/spectroscopy characterizations, we demonstrate that the 1T-ZrTe2 monolayer hosts the charge density wave state, as well as a linear dispersion energy band near Fermi energy, thereby implying the possible coexistence of the topological nontriviality and electron correlation. This work provides a two-dimensional platform for exploring the many body effect in topological nontrivial materials. [ABSTRACT FROM AUTHOR]

Background: Epstein-Barr virus (EBV)-associated gastric carcinomas (EBVaGCs) present unique molecular signatures, but the tumorigenesis of EBVaGCs and the role EBV plays during this process remain poorly understood. Methods: We applied whole-exome sequencing, EBV genome sequencing, and whole-genome bisulfite sequencing to multiple samples (n = 123) derived from the same patients (n = 25), which covered saliva samples and different histological stages from morphologically normal epithelial tissues to dysplasia and EBVaGCs. We compared the genomic landscape between EBVaGCs and their precursor lesions and traced the clonal evolution for each patient. We also analyzed genome sequences of EBV from samples of different histological types. Finally, the key molecular events promoting the tumor evolution were demonstrated by MTT, IC50, and colony formation assay in vitro experiments and in vivo xenograft experiments. Results: Our analysis revealed increasing mutational burden and EBV load from normal tissues and low-grade dysplasia (LD) to high-grade dysplasia (HD) and EBVaGCs, and oncogenic amplifications occurred late in EBVaGCs. Interestingly, within each patient, EBVaGCs and HDs were monoclonal and harbored single-strain-originated EBV, but saliva or normal tissues/LDs had different EBV strains from that in EBVaGCs. Compared with precursor lesions, tumor cells showed incremental methylation in promotor regions, whereas EBV presented consistent hypermethylation. Dominant alterations targeting the PI3K-Akt and Wnt pathways were found in EBV-infected cells. The combinational inhibition of these two pathways in EBV-positive tumor cells confirmed their synergistic function. Conclusions: We portrayed the (epi) genomic evolution process of EBVaGCs, revealed the extensive genomic diversity of EBV between tumors and normal tissue sites, and demonstrated the synergistic activation of the PI3K and Wnt pathways in EBVaGCs, offering a new potential treatment strategy for this disease. [ABSTRACT FROM AUTHOR]

The aim was to investigate the independent prognostic factors and construct a prognostic risk prediction model to facilitate the formulation of oral squamous cell carcinoma (OSCC) clinical treatment plan. We constructed a prognostic model using univariate COX, Lasso, and multivariate COX regression analysis and conducted statistical analysis. In this study, 195 randomly obtained sample sets were defined as training set, while 390 samples constituted validation set for testing. A prognostic model was constructed using regression analysis based on nine survival-associated metabolic genes, among which PIP5K1B, NAGK, and HADHB significantly down-regulated, while MINPP1, PYGL, AGPAT4, ENTPD1, CA12, and CA9 significantly up-regulated. Statistical analysis used to evaluate the prognostic model showed a significant different between the high and low risk groups and a poor prognosis in the high risk group (P < 0.05) based on the training set. To further clarify, validation sets showed a significant difference between the high-risk group with a worse prognosis and the low-risk group (P < 0.05). Independent prognostic analysis based on the training set and validation set indicated that the risk score was superior as an independent prognostic factor compared to other clinical characteristics. We conducted Gene Set Enrichment Analysis (GSEA) among high-risk and low-risk patients to identify metabolism-related biological pathways. Finally, nomogram incorporating some clinical characteristics and risk score was constructed to predict 1-, 2-, and 3-year survival rates (C-index = 0.7). The proposed nine metabolic gene prognostic model may contribute to a more accurate and individualized prediction for the prognosis of newly diagnosed OSCC patients, and provide advice for clinical treatment and follow-up observations. [ABSTRACT FROM AUTHOR]

To increase the reliability and success rate of drug discovery, efforts have been made to increase the C(sp3) fraction and avoid flat molecules. sp3-Rich enantiopure amines are most frequently encountered as chiral auxiliaries, synthetic intermediates for pharmaceutical agents and bioactive natural products. Streamlined construction of chiral aliphatic amines has long been regarded as a paramount challenge. Mainstream approaches, including hydrogenation of enamines and imines, C–H amination, and alkylation of imines, were applied for the synthesis of chiral amines with circumscribed skeleton structures; typically, the chiral carbon centre was adjacent to an auxiliary aryl or ester group. Herein, we report a mild and general nickel-catalysed asymmetric reductive hydroalkylation to effectively convert enamides and enecarbamates into drug-like α-branched chiral amines and derivatives. This reaction involves the regio- and stereoselective hydrometallation of an enamide or enecarbamate to generate a catalytic amount of enantioenriched alkylnickel intermediate, followed by C–C bond formation via alkyl electrophiles. Enantiopure aliphatic amines are frequently encountered as chiral auxiliaries and synthetic intermediates for bioactive compounds. Here, the authors report a mild nickel-catalysed asymmetric reductive hydroalkylation to convert enamides and enecarbamates into α-branched chiral amines and derivatives. [ABSTRACT FROM AUTHOR]

In this study, a direct Z-scheme AgBr/α-Ag2WO4 heterojunction was prepared via in situ anion exchange at room temperature. The construction strategy is energy- and time-saving for large scale syntheses. The α-Ag2WO4 cluster was tightly anchored by converted AgBr nanoparticles of small size in the range of 5–15 nm to induce an effective interfacial effect. The visible light photoactivity of the optimal sample AgBr/α-Ag2WO4-20% is drastically boosted by 53.4- and 26.4-fold towards the degradation of Rhodamine B (RhB) and phenol, respectively. Under the exposure of simulated sunlight, the photocatalytic degradation rate of RhB is also enhanced as high as 12.4 times compared with bare α-Ag2WO4. Besides the enhanced light harvesting, the improved photoactivity is mainly ascribed to the accelerated spatial separation of photoexcited carriers as evidenced by PL and photoelectrochemical analyses. Based on the energy band structure and reactive oxidation species, a solid Z-scheme heterojunction mechanism at the AgBr/α-Ag2WO4 interface is proposed and discussed. The study offers some insight into the design of hetero-photocatalysts containing the same cation with improved photocatalytic behavior in energy and environmental applications. [ABSTRACT FROM AUTHOR]

The Berry phase picture provides important insights into the electronic properties of condensed matter systems. The intrinsic anomalous Hall (AH) effect can be understood as the consequence of non-zero Berry curvature in momentum space. Here, we fabricate TI/magnetic TI heterostructures and find that the sign of the AH effect in the magnetic TI layer can be changed from being positive to negative with increasing the thickness of the top TI layer. Our first-principles calculations show that the built-in electric fields at the TI/magnetic TI interface influence the band structure of the magnetic TI layer, and thus lead to a reconstruction of the Berry curvature in the heterostructure samples. Based on the interface-induced AH effect with a negative sign in TI/V-doped TI bilayer structures, we create an artificial "topological Hall effect"-like feature in the Hall trace of the V-doped TI/TI/Cr-doped TI sandwich heterostructures. Our study provides a new route to create the Berry curvature change in magnetic topological materials that may lead to potential technological applications. Berry curvature connects to exotic electronic phases hence it provides important insights to understand quantum materials. Here, the authors report sign change of the anomalous Hall effect resulted from Berry curvature change at the interface of a topological insulator/magnetic topological insulator heterostructure. [ABSTRACT FROM AUTHOR]

A quantum anomalous Hall (QAH) state is a two-dimensional topological insulating state that has a quantized Hall resistance of h/(Ce2) and vanishing longitudinal resistance under zero magnetic field (where h is the Planck constant, e is the elementary charge, and the Chern number C is an integer)1,2. The QAH effect has been realized in magnetic topological insulators3–9 and magic-angle twisted bilayer graphene10,11. However, the QAH effect at zero magnetic field has so far been realized only for C = 1. Here we realize a well quantized QAH effect with tunable Chern number (up to C = 5) in multilayer structures consisting of alternating magnetic and undoped topological insulator layers, fabricated using molecular beam epitaxy. The Chern number of these QAH insulators is determined by the number of undoped topological insulator layers in the multilayer structure. Moreover, we demonstrate that the Chern number of a given multilayer structure can be tuned by varying either the magnetic doping concentration in the magnetic topological insulator layers or the thickness of the interior magnetic topological insulator layer. We develop a theoretical model to explain our experimental observations and establish phase diagrams for QAH insulators with high, tunable Chern number. The realization of such insulators facilitates the application of dissipationless chiral edge currents in energy-efficient electronic devices, and opens up opportunities for developing multi-channel quantum computing and higher-capacity chiral circuit interconnects. The number of edge channels in quantum anomalous Hall insulators is controlled by varying either the magnetic dopant concentration or the interior spacer layer thickness, yielding Chern numbers up to 5. [ABSTRACT FROM AUTHOR]

The current clinical guidelines on post-traumatic stress disorder (PTSD) recommend selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs) of drugs. However, there is uncertainty about the efficacy of other drugs and selecting which treatments work best for which patients. This meta-analysis evaluated efficacy and acceptability of pharmaceutical management for adults with PTSD. Randomized-controlled trials, which reported active comparators and placebo-controlled trials of pharmaceutical management for adults with PTSD, from the Ovid Medline, EMBase, CENTRAL, PsycINFO, Ovid Health and Psychosocial Instruments, and ISIWeb of Science, were searched until June 21, 2019. In terms of efficacy, all active drugs demonstrated superior effect than placebo (SMD = −0.33; 95% CI, −0.43 to −0.23). The medications were superior to placebo in reducing the symptom of re-experiencing, avoidance, hyperarousal, depression, and anxiety. For acceptability, medicine interventions for PTSD showed no increase in all-cause discontinuation compared with placebo. Nevertheless, in terms of safety, medicine interventions indicated a higher risk of adverse effect compared with placebo (RR = 1.47, 95% CI: 1.24 to 1.75). Compared with placebo, the SSRIs and atypical antipsychotics drugs had significant efficacy whether in patients with severe or extremely severe PTSD status. However, only atypical antipsychotics (SMD = −0.29, 95% CI: −0.48 to −0.10) showed superior efficacy than placebo in veterans. Medication management could be effective in intervention of PTSD, which demonstrated a sufficient improvement in the core symptoms. This meta-analysis supports the status of SSRIs and SNRIs as recommended pharmacotherapy. However, patients with different clinical characteristics of PTSD should consider individualized drug management. [ABSTRACT FROM AUTHOR]

Summary: Aims: Our laboratory previously reported that olanzapine treatment inhibited growth of glioma cell lines and hypothesized that autophagy may be involved in the proliferation inhibitory effects of olanzapine. However, the mechanisms of olanzapine‐contributed autophagy activation are unclear. Methods: The inhibitory effects of olanzapine on glioma cells were evaluated by CCK8 assay, Hoechst 33258 staining and annexin V‐FITC/PI staining. Western blotting, nuclear separation techniques, and immunofluorescence assays were used to investigate the relationship between the inhibition of NF‐κB and autophagy activation by olanzapine. Results: In this work, we verified that olanzapine increased autophagic flux and autophagic vesicles. In addition, we confirmed that autophagy was related to NF‐κB inhibition in cancer progression, especially with the nuclear translocation of p65. Furthermore, we demonstrated that autophagy induced by olanzapine could be impaired with TNFα cotreatment. We also found that olanzapine had an inhibitory effect on T98 cells with positive MGMT protein expression, which may involve the inhibition of MGMT through effects on NF‐κB. Conclusions: Our findings identify a pathway by which olanzapine induces autophagy by depressing NF‐κB in a glioma cell line, providing evidence which supports the use of olanzapine as a potential anticancer drug. [ABSTRACT FROM AUTHOR]

Rock strength is one of the most important parameters in geotechnical engineering. During excavation using a tunnel boring machine (TBM), a rapid and effective method to estimate rock strength is needed. The TBM muck produced during excavation contains blocky fragments which are suitable for a point load test (PLT). To use the PLT on blocky fragments to estimate rock strength, it is necessary to find the relation between the point load strength (PLS) of blocky fragments and uniaxial compressive strength (UCS) of surrounding rocks. In the present study, PLT was performed on both blocky fragments and core samples of limestone for the Yinsong Water Conveyance Project, China. The UCS of limestone was acquired. The PLS of blocky fragments and core samples was compared. The results show that the blocky fragments' PLS is lower than that of core samples; the declining ratio depends on the fractured degree of sampling sites; blocky fragments with width and thickness in a certain range are suitable for estimating rock strength; and when the size of the blocky fragment exceeds a certain range, it means the blocky fragment was not generated from the tunnel face. The limestone core samples simultaneously drilled from side wall have an average conversion factor from PLS to UCS of 24.61. The mean conversion factor from PLS of blocky fragments to UCS of limestone in the present study is 40.38. [ABSTRACT FROM AUTHOR]

Rapid and effective hemostasis for a noncompressible hemorrhage is the key to control bleeding and reduce mortality. Chitosan (CS) has been widely used as a popular hemostatic dressing; however, irregularly shaped wounds present in emergencies limit the performance of CS powder. To improve the hemostatic effect of CS, we modified it with poly(vinyl alcohol) (PVA), a fast-swelling sponge triggered by water. The novel synthetic PVA–CS was prepared by cross-linking PVA and CS during foaming and crosslinking reactions. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction were utilized to analyze the characteristics of PVA–CS. In vitro, the swelling ratio and blood clotting ability were evaluated in different groups with various weight ratios or degrees of deacetylation of the CS, and the cytocompatibility and cell attachment on the material were analyzed by human dermal fibroblast (HDF) cell testing. In vivo, the hemostatic effects were evaluated in Sprague-Dawley rats and Bama miniature pigs in a femoral artery hemorrhage model or gunshot wound experiment. PVA–CS presents robust mechanical strength, rapid water-triggered swelling and a fast absorption speed. As compared with gauze and PVA, which are widely used in first aid, PVA–CS sponges showed an improved blood clotting ability and increased blood cell and platelet adhesion and activation. The PVA–CS sponges also showed high biocompatibility in cell viability, cell proliferation and cell attachment bioassays. Furthermore, in vivo evaluation of the PVA–CS sponges revealed excellent hemostatic performance and enhanced wound healing with increased re-epithelialization and decreased granulation tissues. The results of this study strongly support the use of these composite sponges for noncompressible hemorrhage in acute trauma and ballistic injuries. [ABSTRACT FROM AUTHOR]

The quantum anomalous Hall effect (QAHE) in a magnetic topological insulator system without the need of an external magnetic field becomes of great interest because of its dissipationless spin currents. The proximity effect via a magnetic adlayer is a promising strategy to bring magnetism into a topological insulator (TI) due to its boosted Curie temperature for a realistic application. In this work, a proximity-induced magnetism above 90 K in a TI, (Bi0.25Sb0.75)2Te3, on a ferrimagnetic adlayer with perpendicular magnetic anisotropy, thulium-iron-garnet (TIG), was evidenced directly by using magnetic circular dichroism. A competition between exchange couplings with different sublattice-sites was further revealed element-specifically in a temperature-driven spin-reorientation of TI, bringing an issue on magnetic inhomogeneity at the interface, which might cause difficulties in obtaining QAHE in such a TI/TIG bilayer system. Our results prove directly the robust magnetism of TI above liquid nitrogen temperatures and also give a deep insight into the mechanism of interfacial coupling in the proximity effect for the bilayer of TI and magnetic oxide, which could be essential for the design of a system with QAHE. [ABSTRACT FROM AUTHOR]

Female-released chemical signals are crucial clues for mate-searching males to locate and gain sexual receptivity of conspecific females. Abundant behavioral evidence indicates that female spiders release sex pheromones to guide mate-searching behavior of conspecific mature males. However, the chemical nature of spider pheromones is poorly understood. Females of the funnel-web spider, Allagelena difficilis, employ sit-and-wait tactics for mating. Field observations indicate that males leave their retreats to search for potential mates during the breeding season. Therefore, we investigated whether virgin females release a sex attractant to conspecific males and then explored the chemical nature of the female pheromone. Four fatty acids extracted from the female bodies (palmitic acid, linoleic acid, cis-vaccenic acid and stearic acid) constitute a multiple-component sex attractant to conspecific males in A. difficilis. Unexpectedly, mated females also produce the same fatty acids, but at trace levels. Two-choice experiments showed that males were significantly attracted by the blend of the four fatty acids in appropriate concentrations while avoiding the blend consisting of the same acids at very low concentrations, suggesting that mate-searching males are able to discriminate virgin females from mated females by the quantities of female-specific fatty acids in the funnel-web spider A. difficilis. [ABSTRACT FROM AUTHOR]

Conventional organic solar cell's (OSC) architectures, including rigid transparent substrate (Glass), conductive electrode (Indium tin oxide, ITO) and small working areas, are widely utilized in organic photovoltaic fields. However, such a structure as well as conventional spin-coating method obviously restrict their industrial application. In this article, we report the deposition of silver nanowires (AgNWs) on the flexible substrate by slot-die printing. The obtained AgNWs films exhibited a high transmittance and a low resistance, and were further used as the transparent conductive electrode of OSCs. A typical conjugated polymer, poly[(2,5-bis(2-hexyldecyloxy)phenylene)- alt-(5,6-difluoro-4,7-di(thiophen-2-yl)benzo[c] [1,2,5]thiadiazole)] (PPDT2FBT), was used as the active material to fabricate large-area (7 cm solar cells by a slot-die coating process. The power conversion efficiency (PCE) could reach 1.87% initially and further increased to 3.04% by thermal annealing. Compared to the performance of reference cell on ITO substrate, the result indicated that the AgNWs could be developed as an alternative substitute of conductive electrode to fabricate the large-area flexible OSCs by roll-to-roll printing. [ABSTRACT FROM AUTHOR]

Two series of lanthanide coordination polymers, [Ln(Hdpstc)(H2O)2]n·nH2O (Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), Ho (6), Er (7), Yb (8)) and [Ln(Hdpstc)(phen)(H2O)]n·1.5nH2O (Ln = Pr (9), Nd (10), Eu (11), Tb (12)) (H4dpstc = 3,3′,4,4′-diphenylsulfonetetracarboxylic acid and phen = 1,10-phenanthroline), have been hydrothermally synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction. Isostructural compounds 1–8 and 9–12 exhibit (3,6)-connected 2D layered structures with Hdpstc3− anions as bridges. The Eu3+ and Tb3+ compounds exhibit bright red and green emissions with absolute quantum yields of 11.19% for 2-Eu, 26.05% for 4-Tb, 35.74% for 11-Eu, and 48.05% for 12-Tb. With a rational design strategy, we have constructed a series of Tb3+-doped Eu3+ materials emitting tunable three primary colors towards efficient white light emission with compounds 2-Eu and 4-Tb, and the absolute quantum yield of white light emission is 13.58%. Meanwhile, 4-Tb displays a highly sensitive response toward Fe3+ ions through significant fluorescence quenching of Tb3+. [ABSTRACT FROM AUTHOR]

The paper uses a capital asset pricing model to analyze the market risk in the European Union Emission Trading System (EU ETS) and clean development mechanisms (CDM) and Zipf analysis technology to analyze the carbon price volatility in different expectations of returns in the two markets. The results show that the systematic risk of the EU ETS market is around 0.07 %, but the CDM market is clearly divided into two stages; the systematic risk of the futures contracts in the first stage (DEC09-DEC12) is less than the EU ETS market, but the systematic risk of the futures contracts that enter the market is greater than the EU ETS market and has a higher market sensitivity, although on the unsystematic risk. The CDM market is always greater than the EU ETS market. Abnormal returns in the two carbon markets are both lower than 0.02 %, but CDM is higher. The probability of price down is greater than that of price up. The carbon price is affected by market mechanisms and external factors (economic crisis and environmental policies) in the low expectations of returns. However, in the high expectations of returns, compared with the CDM market, the carbon price change in the EU ETS market is less stable and has higher risks. [ABSTRACT FROM AUTHOR]

Anti-fouling and anti-bacterial polyethersulfone (PES) membranes were developed by the addition of poly(2-dimethylaminoethyl methacrylate) grafted silica nanoparticles (SiO2-g-PDMAEMA NPs) and further post-quaternization. The SiO2-g-PDMAEMA NPs were first synthesized by grafting PDMAEMA brushes from SiO2 NPs via surface-initiated, reversible addition fragmentation chain transfer (RAFT) polymerization. PES/SiO2-g-PDMAEMA hybrid ultrafiltration (UF) membranes were then prepared from the blending solutions of PES and SiO2-g-PDMAEMA NPs via non-solvent induced phase separation (NIPS) process. The PDMAEMA chains incorporated into the PES membranes were further quaternized by reacting with 1,3-propane sultone (1,3-PS) and methyl iodide (CH3I), respectively. After treatment with 1,3-PS, the resulting zwitterionic PES membranes exhibited excellent hydrophilicity, water permeability, solute rejection and protein anti-fouling properties. The cationic membranes obtained from CH3I treatment showed strong anti-bacterial activity against Escherichia coli (E. coli) and Staphyloccocus aureus Rosenbach (S. aureus). This work presents a convenient strategy for anti-biofouling modification of polymer membranes via surface quaternization of the reactive SiO2-g-PDMAEMA NPs additive. [ABSTRACT FROM AUTHOR]

Bacterial contamination reduces the shelf-life of foods and presents serious risks to human health. Nanotechnology provides the opportunity for the development of new antibacterial agents. Nano-inorganic metal oxides have shown the potential to reduce bacterial contamination of foods. When the particle size of materials decreases from the micrometre to the nanometre range, nano-functional properties such as diffusivity, mechanical strength, chemical reactivity and biological properties are improved. Significantly, ZnO has been used in many applications with particular success. Many studies have shown that ZnO nanoparticles have enhanced antibacterial activity. This review discusses the main synthetic methods, antibacterial activity, antibacterial mechanisms and food applications of ZnO nanoparticles. [ABSTRACT FROM AUTHOR]

The acetylcholinesterase of Lepidoptera insects is encoded by two genes, ace1 and ace2. The expression of the ace1 gene is significantly higher than that of the ace2 gene, and mutations in ace1 are one of the major reasons for pesticide resistance in insects. In order to investigate the effects of the mutations in ace1's characteristic sites on pesticide resistance, we generated mutations for three amino acids using site-directed mutagenesis, which were Ala(GCG)303Ser(TCG), Gly(GGA)329Ala(GCA) and Leu (TCT)554Ser(TTC). The Baculovirus expression system was used for the eukaryotic expression of the wild type ace1 ( wace1) and the mutant ace1 ( mace1). SDS-PAGE and Western blotting were used to detect the targeting proteins with expected sizeof about 76 kDa. The expression products were purified for the determination of AChE activity and the inhibitory effects of physostigmine and phoxim. We observed no significant differences in the overall activity of the wild type and mutant AChEs. However, with 10 min of physostigmine (10 μM) inhibition, the remaining activity of the wild type AChE was significantly lower than that of the mutant AChE. Ten min inhibition with 33.4 μM phoxim also resulted in significantly lower remaining activity of the wild type AChE than that of the mutant AChE. These results indicated that mutations for the three amino acids reduced the sensitivity of AChE to physostigmine and phoxim, which laid the foundation for future in vivo studies on AChE's roles in pesticide resistance. [ABSTRACT FROM AUTHOR]

Abstract: miR-20a is an important member of the miR-17–92 cluster, and its real function in cervical cancer cells is unknown. Our study demonstrated that miR-20a was upregulated in cervical cancer tissues. Overexpression of miR-20a in cervical cancer-derived cell lines, HeLa and C-33A, enhanced long-term cellular proliferation, migration and invasion, whereas inhibition of miR-20a suppressed those functions. We also confirmed that oncogenic TNKS2 is directly upregulated by miR-20a. Furthermore, suppression of TNKS2 expression could inhibit colony formation, migration and invasion of cervical cancer cells. Therefore, we concluded that miR-20a can promote migration and invasion of cervical cancer cells through the upregulation of TNKS2. [Copyright &y& Elsevier]

Many real systems can be regarded as complex networks. In this paper, we investigate the influence of traffic assignments on transportation dynamics in complex networks with different topologies. The sequential problem is motivated by the fact that some previous works are only on traffic assignment of user equilibrium (UE). We introduce traffic assignments of system equilibrium (SE) and system optimization (SO) to analyze the relationship between traffic assignments and network topologies. In terms of these traffic assignments, some interesting results concerning system total cost are obtained. Simulation results demonstrate that load distribution also exhibits a power-law behavior for SE and SO assignments in scale-free networks. Furthermore, the exponents for SE and SO assignments are much larger than that for UE assignment. It indicates that traffic assignments play an important role in determining the transportation dynamics in scale-free networks. Finally, cascading failures of link removal in different topologies are discussed. [ABSTRACT FROM AUTHOR]

Fraction 4 (PE-EtOAc, 8:2) was subjected to MCI CC, silica gel CC, LH-20 CC, and semipreparative HPLC to give compounds B 1 b (8.00 mg), B 2 b (2.27 mg), B 4 b (10.00 mg), B 6 b (6.23 mg), B 7 b (5.86 mg), B 8 b (15.70 mg), B 9 b (9.14 mg), and B 15 b (41.60 mg). Fraction 6 (PE-EtOAc, 7:3) was subjected to MCI CC, silica gel CC, LH-20 CC, and semipreparative HPLC to provide compounds B 5 b (7.30 mg), B 10 b (21.70 mg), B 11 b (18.90 mg), B 12 b (22.10 mg), and B 13 b (22.60 mg). Fraction 5 (PE-EtOAc, 6:4) was subjected to MCI CC, silica gel CC, and LH-20 CC to obtain compound B 16 b (28.20 mg). [Extracted from the article]

Background: The effects of drug treatment on veterans, who have a high risk of post-traumatic stress disorder (PTSD), are not clear, and the guidelines are different from the recommendations of the recent meta-analysis. Our goal was to find the efficacy and frequencies of complications of drugs that can treat PTSD in veterans. Method: We searched Ovid MEDLINE, Ovid Embase, The Cochrane Library and Web of Science until January 1, 2020. The outcomes were designed as the change of PTSD total scale, subsymptom score, response rate, frequencies of complications outcomes, and acceptability. Results: We included a total of 36 randomised controlled trials with a total of 2,331 adults. In terms of overall effect, drug treatment is more effective than placebo in change in total PTSD symptoms scale (SMD = −0.24, 95% CI [−0.42, −0.06]) and response (RR = 1.66, 95% CI [1.01, 2.72]). However, in terms of frequencies of complications, drugs generally had a higher withdrawal rate (RR = 1.02, 95% CI [0.86, 1.20]) and a higher frequencies of complications (RR = 1.72, 95% CI [1.20, 2.47]) than placebo. Risperidone showed a good curative effect in change in total PTSD symptoms scale (SMD = −0.22, 95% CI [−0.43, 0.00]) and acceptability (RR = 1.31, 95% CI [0.82, 2.59]). The drugs acting on 5−HT receptors, our results showed that symptoms of hyper−arousal (SMD = −0.54, 95% CI [−0.86, −0.21]), symptoms of re−experiencing (SMD = −0.62, 95% CI [−0.86, −0.39]) and symptoms of avoidance (SMD = −0.53, 95% CI [− 0.77,−0.3]), The drugs acting on dopamine receptors, our results showed that symptoms of re−experiencing (SMD = −0.35, 95% CI [−0.55, −0.16]) and the drugs acting on α2 receptor has a significant effect on reducing total PTSD symptoms scale (SMD = −0.34, 95% CI [−0.62, −0.06]). Conclusion: Drug therapy can effectively treat PTSD, but its frequencies of complications should be considered. Different from the guidelines for adult PTSD, this study supports atypical antipsychotics, selective serotonin reuptake inhibitors and receptors that act on 5-HT and dopamine for the treatment of PTSD in veterans. Based on evidence among these drugs, the risperidone is the most effective for veterans, otherwise, sertraline is used as an alternative. [ABSTRACT FROM AUTHOR]