Search

Mingming Fu,1,* Junfei Guo,2,* Yuqi Zhao,1 Yaqian Zhang,1 Yingze Zhang,2– 4 Zhiqian Wang,1 Zhiyong Hou2,3 1Department of Geriatric Orthopedics, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, People’s Republic of China; 2Department of Orthopaedic Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, 050051, People’s Republic of China; 3NHC Key Laboratory of Intelligent Orthopeadic Equipment (The Third Hospital of Hebei Medical University), Shijiazhuang, Hebei, 050051, People’s Republic of China; 4Chinese Academy of Engineering, Beijing, 100088, People’s Republic of China*These authors contributed equally to this workCorrespondence: Zhiqian WangDepartment of Geriatric Orthopedics, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, 050051, People’s Republic of ChinaEmail w18533112890@163.comZhiyong HouDepartment of Orthopaedic Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei, 050051, People’s Republic of ChinaEmail drzyhou@gmail.comPurpose: Limited information exists on fall-related fractures in older adults with cerebrovascular disease. This study aimed to determine the characteristics of older adults with cerebrovascular disease who sustained fall-related fractures and identify the associated risk factors for perioperative complications.Patients and Methods: This was a cross-sectional study, which included patients with cerebrovascular disease who sustained fractures between Jan. 2017 and Dec. 2019. The collected data included demographics (age and gender), time and place of fracture occurrence, mechanism of injury, fracture location, type of cerebrovascular disease, complications, and comorbidities.Results: A total of 768 patients with 815 fractures were included; there were 253 males and 515 females, with an average age of 78.3 years. For either males or females, 80– 84 years was the most commonly involved age group. Most (61.0%) patients had their fractures occurring at home and most fractures (70.7%) occurred during the daytime. Most were hip fractures and limb weakness; instability-related falls were the most common cause of fracture, making a proportion of 34.5%. Patients who suffered falls were mainly combining ischemic cerebrovascular disease. Most (85.9%) patients presented with at least one comorbid disease and the perioperative complication rate was 76.9% in total cases. Age≥ 80 (OR: 1.772, 95% CI: 1.236– 2.540) and the number of comorbidities≥ 3 (OR: 1.606, 95% CI: 1.035– 2.494) were found independently associated with complications, while the type of cerebrovascular disease, fracture location, and comorbidities of prior fragility fracture and respiratory disease were not significantly correlated with complications.Conclusion: Our findings highlighted that more focus on improved physical function explored in intervention setting and the importance of primary home prevention measures seems justified in China and maybe other countries as well. It is the first study that presented the epidemiological characteristics of older adults with cerebrovascular disease who later experienced a fracture.Keywords: cross-sectional study, epidemiology, fall-related fracture, cerebrovascular disease, older adults

The low-temperature scanning tunneling microscope and spectroscopy (STM/STS) are used to visualize superconducting states in the cleaved single crystal of 9% praseodymium-doped CaFe2As2 (Pr-Ca122) with Tc ≈ 30 K. The spectroscopy shows strong spatial variations in the density of states (DOS), and the superconducting map constructed from spectroscopy discloses a localized superconducting phase, as small as a single unit cell. The comparison of the spectra taken at 4.2 K and 22 K (below vs. close to the bulk superconducting transition temperature) from the exact same area confirms the superconducting behavior. Nanoscale superconducting states have been found near Pr dopants, which can be identified using dI/dV conductance maps at +300 mV. There is no correlation of the local superconductivity to the surface reconstruction domain and surface defects, which reflects its intrinsic bulk behavior. We, therefore, suggest that the local strain of Pr dopants is competing with defects induced local magnetic moments, this competition is responsible for the local superconducting states observed in this Fe-based filamentary superconductor.

Two-dimensional Janus materials have great potential for the applications in spintronic devices due to their particular structures and novel characteristics. However, they are usually non-magnetic in nature. Here, different transition metals (TMs: Co, Fe, Mn, Cr, and V) adsorbed WSSe frameworks are constructed, and their structures and magnetic properties are comprehensively investigated by first-principles calculations. The results show that the top of W atom is the most stable absorption site for all the TM atoms, and all the systems exhibit magnetism. Moreover, their magnetic properties significantly depend on the adsorbed elements and the adsorbent chalcogens. A maximal total magnetic moment of 6 μB is obtained in the Cr-adsorbed system. The induced magnetism from S-surface-adsorption is always stronger than that for the Se-surface-adsorption due to its larger electrostatic potential. Interestingly, the easy magnetization axis in the Fe-adsorbed system switches from the in-plane to the out-of-plane when the adsorption surface changes from Se to S surface. The mechanism is analyzed in detail by Fe-3d orbital-decomposed density of states. This work provides a guidance for the modification of magnetism in low-dimensional systems.

The aim of the present study was to investigate the neuroprotective effects of naringin on the memory impairment of hydrocortisone mice, and to elucidate the potential underlying molecular mechanisms. In the present study, a hydrocortisone model was constructed. Novel object recognition, Morris water maze and step‑down tests were performed in order to assess the learning and memory abilities of mice. Hematoxylin and eosin staining was used to observe pathological changes in the hippocampus and hypothalamus. Transmission electron microscopy was used to observe the ultrastructural changes in the hippocampus. Immunohistochemistry was used to detect the expression of ERα and ERβ. Western blotting was performed to detect the expression of each protein in the relevant system. It was found that naringin can significantly improve cognitive, learning and memory dysfunction in mice with hydrocortisone memory impairment. In addition, naringin can exert neuroprotective effects through a variety of mechanisms, including amyloid β metabolism, Tau protein hyperphosphorylation, acetylcholinergic system, glutamate receptor system, oxidative stress and cell apoptosis. Naringin can also affect the expression of phosphorylated‑P38/P38, indicating that the neuroprotective effect of naringin may also involve the MAPK/P38 pathway. The results of the present study concluded that naringin can effectively improve the cognitive abilities of mice with memory impairment and exert neuroprotective effects. Thus, naringin may be a promising target drug candidate for the treatment of Alzheimer's disease.

The online learning becomes more and more popular where visualization of 3D objects can be employed to lots of fields, e.g., 3D building information modeling for architecture, 3D city model for urban planning, 3D animation for film, 3D skeleton visualization of medical treatment, etc.. In tradition, the most popular tool for 3D modeling and visualization is OpenGL which is based on Client/Server. In another word, C++ code for OpenGL must be installed and configured firstly which is not convenient for new beginners. By contrast, this paper focus on visualization of 3D objects in Computer Graphics and GIS (Geographic Information System) purely depending on JavaScript technology where no additional software or plugins, applet, ActiveX control is needed. Typical JavaScript libraries covers ThreeJS for Computer Graphics, OpenLayers for 2D GIS and CesiumJS for 3D GIS. Based on the above libraries, e-learners could view and manipulate 3D objects in web browser (e.g., Google Chrome). Such intuitive and convenient 3D visualization and manipulation results in much more interesting for learning.

The role of silver localized surface plasmons (LSPs) on the luminescence of a Si(111)-(7 × 7) surface has been investigated by scanning tunneling microscopy (STM) with a silver tip at 77 K. On a bare Si(111)-(7 × 7) surface, a characteristic peak at 1.85 eV dominates the STM-induced luminescence spectrum, although the luminescence intensity is extremely weak. Once Ag atoms are deposited onto the Si surface to form islands with a few atomic layers, it is found that the intensity of the characteristic peak from the Si surface underneath the Ag islands is significantly enhanced by about one order. In addition to the luminescence from the Si surface, light emission originating from the irradiation decay of the Ag plasmons is also detected. Such great enhancement of the luminescence from the Si surface is attributed to the strong coupling between the surface states of the Si and the LSPs of the Ag islands.

To investigate the clinical effects of Xinkeshu combined with levosimendan on perioperative heart failure in oldest-old patients with hip fractures.Oldest-old patients over 80 years old with perioperative heart failure and hip fractures were randomly divided into the control and observation groups, with 50 patients in each group. All patients in both groups were treated with conventional anti-heart failure therapy and levosimendan, whereas patients in the observation group additionally received Xinkeshu tablets. Clinical manifestations; left ventricular ejection fraction (LVEF); left ventricular end-diastolic dimension (LVEDD); left ventricular end-systolic dimension (LVESD); B-type natriuretic peptide (BNP), superoxide dismutase (SOD), malondialdehyde (MDA), nitric oxide (NO), and endothelin-1 (ET-1) levels; and self-rating anxiety scale (SAS) and self-rating depression scale (SDS) scores were compared between before and after treatment to evaluate the curative effects of Xinkeshu combined with levosimendan.After treatment, the efficacy rate was significantly higher in the observation group than in the control group. LVEF and the levels of SOD and NO were higher in the observation group than in the control group after treatment. However, LVEDD; LVESD; BNP, MDA, and ET-1 levels; and the SAS and SDS scores were lower after treatment in the observation group than in the control group.Levosimendan combined with Xinkeshu can improve cardiac function, alleviate oxidative stress, and relieve anxiety and depression in oldest-old patients with perioperative heart failure and hip fracture.

The interplay between magnetism and nontrivial topology in magnetic topological insulators (MTIs) is expected to give rise to exotic topological quantum phenomena like the quantum anomalous Hall effect and the topological axion states. A key to assessing these novel properties is to realize gapped topological surface sates. $\mathrm{Mn}{\mathrm{Bi}}_{2}{\mathrm{Te}}_{4}$ possesses nontrivial band topology with an intrinsic antiferromagnetic state. However, the highly electron-doped nature of the $\mathrm{Mn}{\mathrm{Bi}}_{2}{\mathrm{Te}}_{4}$ crystals obstructs the exhibition of the surface band gap. Here, we tailor the material through Sb substitution to reveal the gapped surface states in $\mathrm{Mn}{\mathrm{Bi}}_{2\text{\ensuremath{-}}x}{\mathrm{Sb}}_{x}{\mathrm{Te}}_{4}$. By shifting the Fermi level into the bulk band gap, we access the surface states and show a band gap of 50 meV at the Dirac point from quasiparticle interference measured by scanning tunneling microscopy (STM). Surface-dominant conduction is confirmed through transport spectroscopy measured by multiprobe STM below the N\'eel temperature. The surface band gap is robust against the out-of-plane magnetic field despite the promotion of field-induced ferromagnetism. The realization of bulk-insulating MTIs with the large exchange gap offers a promising platform for exploring emergent topological phenomena.

The aim of this study was to investigate the effect and mechanism of miR-142-5p/212-5p on the proliferation and collagen formation of cardiac fibroblasts (CFs) after myocardial infarction (MI). The mouse MI model was established by ligation of the left anterior descending coronary artery. CFs were induced by transforming growth factor-beta 1 (TGF-β1) or angiotensin (Ang II). The molecule expressions were measured by qRT-PCR and Western blot. CF proliferation was detected by an MTT assay. The effect of miR-142-5p/212-5p on the luciferase activity of c-Myc 3′UTR was assessed by the luciferase reporter assay. miR-142-5p and miR-212-5p were downregulated in cardiac tissues of MI mice and in TGF-β1- or Ang II-induced CFs, while the protein levels of collagen I and III were upregulated. Moreover, simultaneous overexpression of miR-142-5p/212-5p inhibited the proliferation and collagen formation of TGF-β1- or Ang II-stimulated CFs to a greater extent than either miR-142-5p or miR-212-5p overexpression alone. MiR-142-5p/212-5p targeted c-Myc and negatively regulated its expression. The effects of miR-142-5p/212-5p overexpression on the TP53INP1 protein level and the proliferation and collagen formation of CFs were reversed by c-Myc overexpression. Moreover, overexpression of miR-142-5p/212-5p improved cardiac function and collagen formation of MI mice. Overexpression of miR-142-5p/212-5p cooperatively suppresses the proliferation and collagen formation after MI by regulating c-Myc/TP53INP1.

Streptococcus suis is a pig pathogen and a vector of zoonotic diseases that can cause severe systemic infection in humans. S. suis can colonize the nasal cavity, tonsils, and upper respiratory, genital, and digestive tracts in healthy pigs. Here, to determine prevalence, serotype distribution, and antimicrobial susceptibility of S. suis in healthy pigs, we collected 1813 nasal cavity samples from healthy pigs raised on 17 independent farms in six Chinese provinces between 2016 and 2018. We obtained 223 S. suis isolates (12.3 %) and the antimicrobial susceptibility to a panel of 11 antimicrobial agents was measured by microbroth dilution. Most S. suis isolates (98.7 %) were resistant to at least three classes of antimicrobial agents. The optrA gene conferring resistance to oxazolidinones and phenicols was identified in the chromosome of 27 isolates and on a ∼40-kb plasmid in one isolate; to the best of our knowledge, this was the first report of plasmid-borne optrA gene in S. suis. The genetic environment of optrA showed substantial diversity and could be divided into eleven different types. Interestingly, some fragments of the 89 K pathogenicity island (PAI) were observed together with optrA in 3 isolates, which warrants further attention. Capsular serotypes of S. suis isolates were determined by multiplex PCR. Serotype 29 was the most prevalent, followed by serotype 7 and serotype 2. The presence of highly virulent serotype 2 strains may pose a threat to public health.

Identically sized $\mathrm{Co}$ quantum dots (QDs) are constructed on monolayer tungsten disulfide (${\mathrm{WS}}_{2}$), forming coupled heterostructures. Topographical images investigated by means of in situ scanning tunneling microscopy (STM) show a bias-dependent feature. First-principles-calculated binding energies combined with the simulated STM images identify that the $\mathrm{Co}$ QDs possess a unique magic number, with a tetrahedral ${\mathrm{Co}}_{4}$ configuration. Numerical differential conductance measured by means of scanning tunneling spectroscopy indicates a p-type doping and an Ohmic contact property for the ${\mathrm{Co}}_{4}/{\mathrm{WS}}_{2}$ system. The mechanism of the transport and conduction properties of the coupled heterostructures is further revealed by analyzing the work functions and interfacial interaction. Our findings offer some references for the controlled fabrication of identically sized zero-dimensional and two-dimensional heterostructures, and we propose a feasible strategy for Ohmic interface contact in nanodevices.

The atomic and electronic structures of pristine PdSe

A ring R is said to be strongly $$J_n$$ -clean if n is the least positive integer such that every element a is strongly $$J_n$$ -clean, that is, there exists an idempotent e such that $$ea=ae$$ , $$a-e$$ is a unit and $$ea^n$$ is in the Jacobson radical J(R). It is proved that strongly $$J_n$$ -clean ring is a strongly clean ring with stable range one. If R is an abelian ring (a ring in which all idempotents are central), then R is strongly $$J_n$$ -clean if and only if R / J(R) is strongly $$\pi $$ -regular and idempotents lift modulo J(R). Some examples and basic properties of these rings are studied. Some criterions in terms of solvability of the characteristic equation are obtained for such a $$2\times 2$$ matrix to be strongly $$J_2$$ -clean.

Thin flakes of Cr1/3NbS2 are fabricated successfully via microexfoliation techniques. Temperature-dependent and field-dependent magnetizations of thin flakes with various thicknesses are investigat...

Group-IIIA metal-monochalcogenides with the enticing properties have attracted tremendous attention across various scientific disciplines. With the aim to satisfy the multiple demands of device applications, here we report a design framework on GaSe monolayer in an effort to tune the electronic and magnetic properties through a dual modulation of vacancy doping and electric field. A half-metallicity with a 100% spin polarization is generated in a Ga vacancy doped GaSe monolayer due to the nonbonding 4p electronic orbital of the surrounding Se atoms. The stability of magnetic moment is found to be determined by the direction of applied electric field. A switchable magnetic configuration in Ga vacancy doped GaSe monolayer is achieved under a critical electric field of 0.6 V/A. Electric field induces redistribution of the electronic states. Finally, charge transfers are found to be responsible for the controllable magnetic structure in this system. The magnetic modulation on GaSe monolayer in this work offers some references for the design and fabrication of tunable two-dimensional spintronic device.

We investigate the electric-field-dependent optical properties and electronic behaviors of GaS monolayer by using the first-principles calculations. A reversal of the dipole transition from E//c to E⊥c anisotropy is found with a critical external electric field of about 5 V/nm. Decomposed projected band contributions exhibit asymmetric electronic structures in GaS interlayers under the external electric field, which explains the evolution of the absorption preference. Spatial distribution of the partial charge and charge density difference reveal that the strikingly reversed optical anisotropy in GaS ML is closely linked to the additional crystal field originated from the external electric field. These results pave the way for experimental research and provide a new perspective for the application of the monolayer GaS-based two-dimensional electronic and optoelectronic devices.

Combined scanning tunneling microscopy, spectroscopy and local barrier height (LBH) studies show that low-temperature-cleaved optimally-doped Ba(Fe1-xCox)2As2 crystals with x=0.06, with Tc = 22 K, have complicated morphologies. Although the cleavage surface and hence the morphologies are variable, the superconducting gap maps show the same gap widths and nanometer size inhomogeneities irrelevant to the morphology. Based on the spectroscopy and LBH maps, the bright patches and dark stripes in the morphologies are identified as Ba and As dominated surface terminations, respectively. Magnetic impurities, possibly due to cobalt or Fe atoms, are believed to create local in-gap state and in addition suppress the superconducting coherence peaks. This study will clarify the confusion on the cleavage surface terminations of the Fe-based superconductors, and its relation with the electronic structures., Accepted to Nano Letters (5 figures)

Group-IIIA metal-monochalcogenides have attracted increasing interests due to their optoelectronic and spin electronic properties. Achieving the modification of their magnetism is desirable for device applications. In our work, structural, electronic, and magnetic properties of the Fe adsorbed GaSe monolayer are studied systematically using density functional theory (DFT). It is found that there is a strong orbit coupling effect between Fe and the vicinal Ga and Se atoms, resulting in a half-metallicity with a 100% spin polarization. The magnetic moments of the nearest neighbour Ga and Se atoms are −0.004 μB and −0.178 μB, respectively, demonstrating an antiferromagnetic coupling with the adsorbed Fe atom. Meanwhile, the induced majority and minority spin states are inclined to distribute on the Se and Ga atoms separately. The hybridization of Fe-3d, Se-4p, and Ga-4p orbitals is responsible for the induced magnetic moments and spin polarization in the nonmagnetic GaSe monolayer. These investigations shed light on understanding the electronic and magnetic properties of the ferromagnetic/GaSe adsorption system, which offer some references for the design and construction of two-dimensional spin nanostructures.

Background Plasmid-mediated mechanisms of drug resistance accelerate the spread of polymyxin resistance, leaving clinicians with few or no antibacterial options for the treatment of infections caused by MDR bacteria, especially carbapenemase-producing strains. Objectives To evaluate the associations among promoter sequence variation, mcr-1 expression, host factors and levels of colistin resistance and to propose antisense agents such as peptide nucleic acids (PNAs) targeting mcr-1 as a tool to restore colistin susceptibility through modulation of MCR-1 expression in Escherichia coli. Methods A β-galactosidase assay was performed to study mcr-1 promoter activity. Quantitative real-time PCR and western blot assays were used to identify the expression level of MCR-1 in WT strains and transformants. Three PNAs targeting different regions of mcr-1 were designed and synthesized to determine whether they can effectively inhibit MCR-1 expression. MIC was measured to test colistin susceptibility in the presence or absence of PNA-1 in mcr-1-carrying E. coli. Results Variation in the mcr-1 promoter sequence and host species affect promoter activity, MCR-1 expression levels and colistin MICs. One PNA targeting the ribosome-binding site fully inhibited the expression of mcr-1 at a concentration of 4 μM, resulting in significantly increased susceptibility to colistin. The MIC90 of colistin decreased from 8 to 2 mg/L (P Conclusions These findings suggest that the antisense approach is a possible strategy to combat mcr-1-mediated resistance as well as other causes of emerging global resistance.

In order to improve the general problem of irregular coating morphology and low mechanical strength of the coating layer in existing coating desensitization technology, nano-cyclotrimethylene trinitramine/melamine-urea-formaldehyde (RDX/MUF) composite energetic microspheres were prepared by an improved emulsion polymerization, taking the MUF as the binder and RDX as the main explosive. In order to judge whether RDX/MUF possessed good stability, the combination of differential scanning calorimetry (DSC) and molecular dynamics (MD) simulation was used to determine the level of binding binding energy between urea-formaldehyde resin binder (UF) and RDX. In addition, to investigate the optimal reaction temperature for the preparation of MUF/RDX, the binding energy between UF and RDX at different temperatures was simulated. And then the morphology and thermal properties of the as-prepared composite energetic microspheres were analyzed by scanning electron microscopy (SEM) and DSC, the impact sensitivity and friction sensitivity of the resultant samples were tested as well. Moreover, RDX/MUF with the same MUF content was prepared by physical mixing for comparative analysis. MD simulation demonstrated that UF and RDX possessed good binding ability at 298 K. The DSC method indicatec that UF and RDX had good compatibility, and the comprehensive performance of RDX after coating was not significantly deteriorated, The optimal binding temperature between UF and RDX was 60~70 &deg, C which is consistent with the experimental results. The experimental results showed that the optimum process conditions for the preparation of RDX/MUF could be listed as follows: the temperature for preparing RDX/MUF composite energetic microspheres by the improved emulsion polymerization was 70 &deg, C the optimal pH value of the urea-formaldehyde resin prepolymer solution was 3, and the optimal melamine-urea molar ratio was 0.4.

Highly repeatable fabrication of compact perovskite films is crucial for large-area perovskite cells (PSCs) in commercial applications. In this work, a vapor-assisted method with the combination of spin-coating and thermal evaporation is employed to fabricate the double-layer PbI2/PbIxBr(2-x) precursor. It is found that surface morphologies of perovskite films could be tailored through tuning the spin-coating speed (the first precursor layer) and chemical compositions (the second precursor layer). The continuous pinhole-free perovskite films are successfully fabricated by double-layer PbI2/PbBr2 precursors. The open-circuit voltages of all the corresponding cells exceed 1.00 V, showing an average value of 1.02 V. The high mean voltage and small variation reveals high repeatability of this method. This work provides a potential method to achieve large-area and high-efficiency PSCs.

The electronic structure inhomogeneities in Co, Ni, and Cr doped BaFe2As2 122 single crystals are compared using scanning tunneling microscopy/spectroscopy (STM/S) at the nanoscale within three bulk property regions in the phase diagram: a pure superconducting (SC) dome region (Co-122), a coexisting SC and antiferromagnetic (AFM) region (Ni-122), and a non-SC region (Cr-122). Machine learning is utilized to categorize the various nanometer scale inhomogeneous electronic states, described here as in-gap, L-shape and S-shape states immersed into the SC matrix for Ni-and Co-doped 122, and L-shape and S-shape states into the metallic matrix for Cr-doped 122. Although the relative percentages of in-gap, L-shape and S-shape states vary in the three samples, the total volume fraction of the three electronic states is quite similar. This is coincident with the number of electrons (Ni0.04 and Co0.08) and holes (Cr0.04) doped into the 122 compound. By combining the volume fractions of the three states, the local density of states (LDOS), magnetic field dependent behavior and global properties in these three samples, the in-gap state is confirmed as a magnetic impurity state from the Co or Ni dopants. In addition, the L-shape state is identified as a spin density wave (SDW) which competes with the SC phase, and the S-shape state is found to be another form of magnetic order which constructively cooperates with the SC phase, rather than competing with it. The comparison of the vortex structures indicates that the inhomogeneous electronic states serve as pinning centers for stabilizing the vortex lattice.

Photodetectors based on photoconductivity effect are usually driven by an external power source. A self-powered photodetector can be powered by incident light using the photovoltaic effect. Here, photoelectrochemical cells with periodically aligned ZnO/CdS nanowire arrays as photoanodes were fabricated and investigated for detecting UV and visible light. At zero bias, this self-powered UV–visible photodetector showed high responsivities of 35.4 and 23.2 mA/W for UV and visible light, a fast rise time of 0.18 s, and a decay time of 0.32 s. The spectral responses of the self-powered photodetectors based on ZnO/CdS nanowire arrays exhibited superior photoresponse in both UV and visible regions in comparison with ZnO nanowire film and ZnO nanowire arrays. The high photosensing performance originates from the excellent light trapping ability at broadband wavelengths and the high charge collection efficiency of the highly ordered ZnO/CdS nanowire arrays. The results indicate that the ZnO/CdS heterojunctions with periodic nanostructures provide a facile frame for UV–visible detecting applications.

Two-dimensional materials such as layered transition-metal dichalcogenides (TMDs) are ideal platforms for studying defect behaviors, an essential step towards defect engineering for novel material functions. Here, we image the 3D lattice locations of selenium-vacancy ${V}_{\text{Se}}$ defects and manipulate them using a scanning tunneling microscope (STM) near the surface of ${\mathrm{PdSe}}_{2}$, a recently discovered pentagonal layered TMD. The ${V}_{\text{Se}}$ show a characterisitc charging ring in a spatially resolved conductance map, based on which we can determine its subsurface lattice location precisely. Using the STM tip, not only can we reversibly switch the defect states between charge neutral and charge negative, but also trigger migrations of ${V}_{\text{Se}}$ defects. This allows a demonstration of direct ``writing'' and ``erasing'' of atomic defects and tracing the diffusion pathways. First-principles calculations reveal a small diffusion barrier of ${V}_{\text{Se}}$ in ${\mathrm{PdSe}}_{2}$, which is much lower than S vacancy in ${\mathrm{MoS}}_{2}$ or an O vacancy in ${\mathrm{TiO}}_{2}$. This finding opens an opportunity of defect engineering in ${\mathrm{PdSe}}_{2}$ for such as controlled phase transformations and resistive-switching memory device application.

Thin flakes of Cr

Two-dimensional materials such as layered transition-metal dichalcogenides (TMDs) are ideal platforms for studying defect behaviors, an essential step towards defect engineering for novel material functions. Here, we image the 3D lattice locations of selenium-vacancy V_{Se} defects and manipulate them using a scanning tunneling microscope (STM) near the surface of PdSe_{2}, a recently discovered pentagonal layered TMD. The V_{Se} show a characterisitc charging ring in a spatially resolved conductance map, based on which we can determine its subsurface lattice location precisely. Using the STM tip, not only can we reversibly switch the defect states between charge neutral and charge negative, but also trigger migrations of V_{Se} defects. This allows a demonstration of direct "writing" and "erasing" of atomic defects and tracing the diffusion pathways. First-principles calculations reveal a small diffusion barrier of V_{Se} in PdSe_{2}, which is much lower than S vacancy in MoS_{2} or an O vacancy in TiO_{2}. This finding opens an opportunity of defect engineering in PdSe_{2} for such as controlled phase transformations and resistive-switching memory device application.

This paper describes HCCL team systems that participated in SemEval 2018 Task 8: SecureNLP (Semantic Extraction from cybersecurity reports using NLP). To solve the problem, our team applied a neural network architecture that benefits from both word and character level representaions automatically, by using combination of Bi-directional LSTM, CNN and CRF (Ma and Hovy, 2016). Our system is truly end-to-end, requiring no feature engineering or data preprocessing, and we ranked 4th in the subtask 1, 7th in the subtask2 and 3rd in the SubTask2-relaxed.

The long-term productivity of a soil is greatly influenced by cation exchange capacity (CEC). Moreover, interactions between dominant base cations and other nutrients are important for the health and stability of grassland ecosystems. Soil exchangeable base cations and cation ratios were examined in a 11-year experiment with sheep manure application rates 0–1,500 g/(m2·a) in a semi-arid steppe in Inner Mongolia of China, aiming to clarify the relationships of base cations with soil pH, buffer capacity and fertility. Results showed that CEC and contents of exchangeable calcium (Ca2+), magnesium (Mg2+), potassium (K+) and sodium (Na+) were significantly increased, and Ca2+ saturation tended to decrease, while K+ saturation tended to increase with the increases of sheep manure application rates. The Ca2+/Mg2+ and Ca2+/K+ ratios decreased, while Mg2+, K+ and Na+ saturations increased with increasing manure application rates. Both base cations and CEC were significantly and positively correlated with soil organic carbon (SOC) and soil pH. The increases of SOC and soil pH would be the dominant factors that contribute to the increase of cations in soil. On a comparison with the initial soil pH before the experiment, we deduced that sheep manure application could partly buffer soil pH decrease potentially induced by atmospheric deposition of nitrogen and sulfur. Our results indicate that sheep manure application is beneficial to the maintenance of base cations and the buffering of soil acidification, and therefore can improve soil fertility in the semi-arid steppes of northeastern China.

Combined scanning tunneling microscopy, spectroscopy, and local barrier height (LBH) studies show that low-temperature-cleaved optimally doped Ba(Fe

Nanostructures decorated with noble metal nanoparticles (NPs) exhibit potential for use in highly sensitive optoelectronic devices through the localized surface plasmon resonance (LSPR) effect. In this study, Faraday rotation was significantly enhanced through the structural optimization of ferromagnetic (FM)/semiconductor composite nanostructures. Experimental and theoretical results revealed that the position of noble metal NPs significantly influenced the coupling of the LSPR-enhanced electromagnetic field with FM materials. Furthermore, nanostructures embedded with noble metals demonstrated an improved capability to efficiently use the electromagnetic field compared to other structures. The Faraday rotation of ZnO/Ag(NPs)/Fe was enhanced 58 fold compared to that of the ZnO(film)/Fe. This work provides a basis for the design of nanoarchitectures for miniaturized high-performance magneto-optical devices.

Burkitt lymphoma (BL) has been reported to be strongly associated with Epstein-Barr virus (EBV) infection. The fact that EBV is generally present in cancer cells but rarely found in healthy cells represents an opportunity for targeted cancer therapy. One approach is to activate the lytic replication cycle of the latent EBV. Nuclear factor (NF)-κB is thought to play an essential role in EBV lytic infection. Elevated NF-κB levels inhibit EBV lytic replication. Parthenolide (PN) is a sesquiterpene lactone found in medicinal plants, particularly in feverfew (Tanacetum parthenium). The aim of the present study was to analyze the effect of PN on the survival of Raji EBV-positive lymphoma cells. Raji cells were treated with 0, 4 or 6 µmol/l PN for 48 h. MTT assay and western blot analysis were performed to evaluate the findings. Results showd that PN suppressed the growth of the EBV-positive BL cell line, Raji, and activated the transcription of BZLF1 and BRLF1 by inhibiting NF-κB activity. Most notably, when PN was used in combination with ganciclovir (GCV), the cytotoxic effect of PN was amplified. These data suggest that the induction of lytic EBV infection with PN in combination with GCV may be a viral‑targeted therapy for EBV-associated BL.

Perpendicular magnetic anisotropy is significantly important for realizing a long-term retention of information for spintronics devices. Inspired by 2D graphene with its high charge carrier mobility and long spin diffusion length, we report a first-principles design framework on perpendicular magnetic anisotropy engineering of a Fe atom adsorbed graphene by employing a O-terminated MgO (1 1 1) substrate. Determined by the adsorption sites of the Fe atom, a tunable magnetic anisotropy is realized in Fe/graphene/MgO (1 1 1) structure, with the magnetic anisotropy energy of −0.48 meV and 0.23 meV, respectively, corresponding to the in-plane and out of plane easy magnetizations. Total density of states suggest a half-metallicity with a 100% spin polarization in the system. Decomposed densities of Fe-3d states reveal the orbital contributions to the magnetic anisotropy for different Fe adsorption sites. Bonding interaction and charge redistribution regulated by MgO substrate are found responsible for the novel perpendicular magnetic anisotropy engineering in the system. The effective manipulation of perpendicular magnetic anisotropy in present work offers some references for the design and construction of 2D spintronics devices.

Based on the systematic study of electropolishing process, an improved tungsten STM probe fabrication technique has been presented. The proper combination of pulse current and the electrolyte concentration is explored for the elimination of impurities and achieves high quality probes with ultra-smooth surfaces. An optimized immersion depth of tungsten wire in electrolyte is proposed for the purpose of realizing the probe with sharp apex as well as high aspect ratio structure. A control strategy for determining the power-off instant during the procedure of electropolishing is developed which will facilitate the fabrication of probe with exponential contour as well as ultrasharp tip. The proposed technique and process are experimentally confirmed to have advantages for the STM probe fabrication of the stabilized stylus contour, typically with apex radius of 30 nm and the yield rate reaches as high as 85%.

The perpendicular magnetic anisotropy (PMA) of Fe1−x Co x thin films on MgO(001) was investigated via first-principles density-functional calculations. Four different configurations were considered based on their ground states: Fe/MgO, Fe12Co4/MgO, Fe10Co6/MgO, and Fe8Co8/MgO. As the Co composition increases, the amplitude of PMA increases first from Fe/MgO to Fe12Co4/MgO, and then decreases in Fe10Co6/MgO; finally, the magnetic anisotropy becomes horizontal in Fe8Co8/MgO. Analysis based on the second-order perturbation of the spin-orbit interaction was carried out to illustrate the contributions from Fe and Co atoms to PMA, and the differential charge density was calculated to give an intuitive comparison of 3d orbital occupancy. The enhanced PMA in Fe12Co4/MgO is ascribed to the optimized combination of occupied and unoccupied 3d states around the Fermi energy from both interface Fe and Co atoms, while the weaker PMA in Fe10Co6/MgO is mainly attributed to the modulation of the interface Co-d xy orbital around the Fermi energy. By adjusting the Co composition in Fe1−x Co x , the density of states of transitional metal atoms will be modulated to optimize PMA for future high-density memory application.

Interacting RNA complexes are studied via bicellular maps using a filtration via their topological genus. Our main result is a new bijection for RNA-RNA interaction structures and a linear time uniform sampling algorithm for RNA complexes of fixed topological genus. The bijection allows to either reduce the topological genus of a bicellular map directly, or to lose connectivity by decomposing the complex into a pair of single stranded RNA structures. Our main result is proved bijectively. It provides an explicit algorithm of how to rewire the corresponding complexes and an unambiguous decomposition grammar. Using the concept of genus induction, we construct bicellular maps of fixed topological genus g uniformly in linear time. We present various statistics on these topological RNA complexes and compare our findings with biological complexes. Furthermore we show how to construct loop-energy based complexes using our decomposition grammar.

Aiming at the analysis of the interactions between port and economy, system dynamic model was used to construct a port-economy system and the causality among the key factors in port production and economy operation has been analyzed to establish a system dynamic flow and variable framework. By using a domestic port and its surrounding area as an example, the grade of the interaction between the port and economy was calculated, and results show that the system dynamic model is effective.

In order to realize high-speed and real-time collection of data and facilitate data analysis and processing, a USB data acquisition system with acquisition, display and storage function was designed in this paper. The hardware of the system consists mainly of AT89S51 as the local processor and PDIUSBD12 as the USB interface device, and the underlying data communication is operated by the firmware and drivers. The application program is developed with LabVIEW under Windows platform. The experimental result shows that the system can work stably and effectively. The USB data acquisition system is easy to operate and portable. In many situations, the system will be a powerful tool for data acquisition and analysis.

In the chemical laboratory, sometimes it is necessary to monitor some data, and store them for analysis. So a multi-channel USB data acquisition system was designed in the paper to achieve the real-time and high-speed data acquisition which is needed. In the system, the slave computer was composed of 8051 and AD7819 as data acquisition module. And it was connect with the host computer through the USB interface device PDIUSBD12. The application of the system was designed with Visual Basic 6.0, which can develop windows applications easily. Through system debugging, The system can effectively complete the data acquisition when working with chemical sensors in the laboratory. The system will give our laboratory technician great help in many situations.

A switched-capacitor (SC) biquad band-pass filter for very low-voltage applications is designed and fabricated in 1mum CMOS process, which can operate at 1V supply voltage, consuming 287muW at room temperature. In the SC filter circuit proposed, a novel rail-to-rail operational amplifier is used to obtain the maximum dynamic range. The band-pass filter has BW-3dB=101Hz at its central frequency of 376Hz

Although it has become the mainstay properties of world economy, the development of the logistics industry is now out of balance: there are very few cases that have succeeded when referring to the transportation and distribution of bulk cargo. The paper presents a thorough research on iron ore logistics centering ports that act as active players in the supply chain, and builds up an order-transportation-inventory system with multi-suppliers and multi-users. Then a mathematical model is established to analyse an optimal logistic system to achieve minimum integrated circulating cost with full consideration of the profits of ports, carriers and shippers, by which the authors hope to provide a practical way for the development of the domestic iron ore logistics.