External fields effectively switch the spin channels of transition metal-doped ß-phase tellurene from first principles.

Non-volatile magnetic random-access memories have proposed the need for spin channel switching. However, this presents a challenge as each spin channel reacts differently to the external field. Tellurene is a semiconductor with a tunable bandgap, excellent stability, and high carrier concentration, but its lack of magnetic properties has hindered its application in spintronics. In this work, the influence of an external field on transition metal (TM)-doped ß-tellurene is systematically analysed from first principles. First, the active-learning moment-tensor-potential (MTP) is used to verify the thermal stability of the V-doped system with the MTP proving to be 900 times faster than the traditional method. Subsequently, under biaxial strain ranging from -2% to 10%, the V-doped system undergoes a gradual transition from a magnetic semiconductor to a spin-gapless semiconductor, and further to a half-metal and magnetic metal. The band structure can be maintained under an electric field. By examining the magnetic anisotropy energy, the lattice changes profoundly impact the electromagnetic properties, particularly with the TMs being sensitive to strain. Moreover, the band structure is reflected in the spin resolution current of the magnetic tunnel junction. This work investigates the response of doped ß-Te to external fields, revealing its potential applications in spintronics.

Spin-gapless van der Waals heterostructure for spin gating through magnetic injection devices.

Spin-gapless semiconductors (SGSs) are new magnetic zero-bandgap materials whose band structure is extremely sensitive to external influences (pressure or magnetic fields) and have great potential for high-speed and low-energy spintronics applications. The first-principles method was used to systematically study the heterostructures constructed of an asymmetric surface-functionalized Janus MXene material, Cr2NOF, and a two-dimensional hexagonal lattice (2DH) semiconductor material and to study the effects of the electronic structure, Curie temperature, magnetism, and the design of unusual band structures and magnetic injection in the bilayer to obtain an SGS structure. Through the design and construction of Cr2NOF/2DH van der Waals heterojunction spintronic devices, the spin-filtering effect of the devices can reach 100%, especially, realizing spin gating through magnetic injection. We report the transport mechanism of the heterojunction spintronic devices to achieve the goal of a controllable optimization of the device functions, which provides a theoretical basis for the design of MXene van der Waals heterojunctions for high-efficiency and low-power-consumption spintronic devices.

Interface engineering strategy for multisource spintronic devices via TMPS4 modulation of black-phosphorus.

Interface engineering is an effective strategy for significantly providing performance improvements in logic operations and information storage techniques, given the quantum effects characteristic of pristine two-dimensional ferromagnetic (FM) materials. Furthermore, the van der Waals (vdW) heterostructures enable a more efficient design of logic components. Herein, two novel designs of van der Waals heterostructures are proposed, black-phosphorus (BP)/TMPS4(TM = Cr, Fe-Mn), where the CrPS4 relies on odd and even layers for FM state - antiferromagnetic (AFM) state alternation, which is used to modulate BP with high hole mobility but no magnetism. Based on the first principles, the simulation results show that the two heterojunctions exhibit high stability, carrier mobility, and thermoelectric effects, of which the BP/CrPS4 heterojunction is specifically modulated to a type II electronic bandstructure. These two structures are applied in multi-source logic devices. The device performances show that the devices have spin Sebeck effect (SSE), perfect spin filtering effect (SFE), high extinction ratio (1347), and high thermal magnetoresistivity (1011). The above results suggest BP/TMPS4 bilayers as promising candidates for spin-based vdW devices and facilitate the future development of atomically thin magnetic information storage.

Association between different MAP levels and 30-day mortality in sepsis patients: a propensity-score-matched, retrospective cohort study.

BACKGROUND: Sepsis is a life-threatening organ dysfunction caused by the infection-related host response disorder. Adequate mean arterial pressure is an important prerequisite of tissue and organ perfusion, which runs through the treatment of sepsis patients, and an appropriate mean arterial pressure titration in the early-stage correlates to the positive outcome of the treatment. Therefore, in the present study, we aimed to elucidate the relationship between early mean arterial pressure levels and short-term mortality in sepsis patients. METHODS: We included all suspected sepsis patients from MIMIC-III database with average mean arterial pressure ≥ 60 mmHg on the first day of intensive care unit stay. Those patients were then divided into a permissive low-mean arterial pressure group (60-65 mmHg) and a high-mean arterial pressure group (> 65 mmHg). Multivariate Cox regression analysis was conducted to analyze the relationship between MAP level and 30-day, 60-day, and 100-day mortality of suspected sepsis patients in the two groups. Propensity score matching, inverse probability of treatment weighing, standardized mortality ratio weighting, PA weighting, overlap weighting, and doubly robust analysis were used to verify our results. RESULTS: A total of 14,031 suspected sepsis patients were eligible for inclusion in our study, among which 1305 (9.3%) had an average first-day mean arterial pressure of 60-65 mmHg, and the remaining 12,726 patients had an average first-day mean arterial pressure of more than 65 mmHg. The risk of 30-day mortality was reduced in the high mean arterial pressure group compared with the permissive low-mean arterial pressure group (HR 0.67 (95% CI 0.60-0.75; p < 0.001)). The higher mean arterial pressure was also associated with lower 60-day and 100-day in-hospital mortality as well as with shorter duration of intensive care unit stay. Patients in the high-mean arterial pressure group also had more urine output on the first and second days of intensive care unit admission. CONCLUSIONS: After risk adjustment, the initial mean arterial pressure of above 65 mmHg was associated with reduced short-term mortality, shorter intensive care unit stay, and higher urine volume in the first two days among patients with sepsis.

A UWB/INS Trajectory Tracking System Application in a Cycling Safety Study.

This paper focuses on the safety issue for cyclists and pedestrians at unsignalized intersections. The cycling speed needs to be calmed when approaching the intersection. This study proposes and deploys an integrated portable ultra-wideband/inertial navigation system (UWB/INS) to extract cycling trajectories for a cycling safety study. The system is based on open-source hardware and delivers an open-source code for an adaptive Kalman filter to enhance positioning precision for data quality assurance at an outdoor experimental site. The results demonstrate that the system can deliver reliable trajectories for low-mobility objects. To mitigate accident risk and severity, varied cycling speed calming measures are tested at an experimental site. Based on the trajectory data, the statistical features of cycling velocities are evaluated and compared. A new proposed geometric design is found to be most effective when compared with conventional traffic signs.

Fast and stable Fourier ptychographic microscopy based on improved phase recovery strategy.

Fourier ptychographic microscopy (FPM) imaging is a computational imaging technology that can reconstruct wide-field high-resolution (HR) images. It uses a series of low-resolution images captured by a camera under different illumination angles. The images are stitched in the Fourier domain to expand their spectral range. Under high-angle illumination, a dark-field image is noisy with a low signal-to-noise ratio, which significantly reduces the reconstruction quality of FPM. Conventional reconstruction algorithms often have low FPM imaging performance and efficiency due to optimization strategies. In response to these problems, this paper proposes an FPM imaging method based on an improved phase recovery strategy to optimize the alternating iterative algorithm. The technique uses an improved threshold method to reduce noise in the image preprocessing stage to maximize the retention of high-frequency sample information. Moreover, an adaptive control factor is added in the subsequent iterative update process to balance the sample spectrum function. This study verifies the effectiveness of the proposed method on both simulation and experimental images. The results show that the proposed method can effectively suppress image background noise and has a faster convergence speed and higher robustness. In addition, it can be used to reconstruct HR complex amplitude images of objects under wide field-of-view conditions.

A first-principles study of the ultra-high spin rectification effect based on nitride MXenes (Sc2NO2, Ti2NO2).

Nitride MXenes exhibit inherent strong chemical stability and ferromagnetic properties, which are significant for their application in nanoscale spintronic devices. To demonstrate the potential of nitride MXenes in spintronics, we have designed a Sc2NO2/Ti2NO2 heterojunction and investigated its spin transport properties using first principles calculations combined with the non-equilibrium Green's function. The results show that the Sc2NO2/Ti2NO2 heterojunction has a stable negative differential resistance effect and a great spin rectification effect with a rectification ratio of 1.73 × 1011. The corresponding energy band structures and the transport behavior establish the mechanism for such properties. In addition, the perfect two-dimensional morphology provides a suitable nanostructured material for developing spintronic devices.

The electromagnetic performance of transition metal-substituted monolayer black arsenic-phosphorus.

Recently, a new two-dimensional nonmagnetic semiconductor material, black arsenic-phosphorus (bAsP), has gained great research attention for experimental and theoretical works owing to its excellent physical properties. The present work attempted to investigate the electromagnetic properties of three 1 : 1 bAsP structures (bAsP-1, bAsP-2, and bAsP-3) substituted with transition metals (TM) by using first principles. Among these substituted bAsP systems, V substitutes P of bAsP-1, Ni substitutes As of bAsP-1, Mn substitutes P of bAsP-2, Fe substitutes As of bAsP-2 and Mn substitutes P of bAsP-3 and these are found to be half-metals. Among them, the system where Ni substitutes As of the bAsP-1 shows the largest binding energy and is the most stable structure. The system where one Ni atom substitutes As of bAsP-1 (As_Ni) and the system where two Ni atoms substitute As of bAsP-1 (2As_2Ni) are selected to develop magnetic tunnel junctions where it is found that the increase in the concentration of Ni in the electrodes increases the spin polarized current. More interestingly, a perfect spin filtering effect with 100% spin polarization and tunnel magnetoresistance of above 104% can be obtained in the one Ni substituted-system (As_Ni) and two Ni-substituted system (2As_2Ni). The negative differential resistance ratio is as high as 3.2 × 107% when the voltage is 0.5 V in the parallel spin configuration of As_Ni. The present research displays that the TM-substituted bAsP structure can be used in the fabrication of spintronic devices.

Low-cost sensors as an alternative for long-term air quality monitoring.

Low-cost air quality sensors are increasingly being used in many applications; however, many of their performance characteristics have not been adequately investigated. This study was conducted over a period of 13 months using low-cost air quality monitors, each comprising two low-cost sensors, which were subjected to a wide range of pollution sources and concentrations, relative humidity and temperature at four locations in Australia and China. The aim of the study was to establish the performance characteristics of the two low-cost sensors (a Plantower PMS1003 for PM2.5 and an Alphasense CO-B4 for carbon monoxide, CO) and the KOALA monitor as a whole under various conditions. Parameters evaluated included the inter-variability between individual monitors, the accuracy of monitors in comparison with the reference instruments, the effect of temperature and RH on the performance of the monitors, the responses of the PM2.5 sensors to different types of aerosols, and the long-term stability of the PM2.5 and CO sensors. The monitors showed high inter-correlations (r > 0.91) for both PM2.5 and CO measurements. The monitor performance varied with location, with moderate to good correlations with reference instruments for PM2.5 (0.44< R2 < 0.91) and CO (0.37< R2 < 0.90). The monitors performed well at relative humidity < 75% and high temperature conditions; however, two monitors in Beijing failed at low temperatures, probably due to electronic board failure. The PM2.5 sensor was less sensitive to marine aerosols and fresh vehicle emissions than to mixed urban background emissions, aged traffic emissions and industrial emissions. The long-term stability of the PM2.5 and CO sensors was good, while CO relative errors were affected by both high and low temperatures. Overall, the KOALA monitors performed well in the environments in which they were operated and provided a valuable contribution to long-term air quality monitoring within the elucidated limitations.

An experimental application of laser-scattering sensor to estimate the traffic-induced PM2.5 in Beijing.

Traffic-induced air pollutant emissions are currently rising rapidly. However, measurement of the roadside environment and calculation of the emission factors for traffic-induced PM2.5 are restricted to certain locations and periods due to the limitations of conventional air monitoring techniques. This paper introduces a portable sensor package with a laser light-scattering PM2.5 sensor and an electrochemical CO sensor to measure roadside PM2.5 and CO concentrations. The low-cost sensor package underwent local calibration using reference instruments at the Chinese Research Academy of Environmental Sciences (CRAES). The results showed a high level of correlation (r in the range of 0.94-0.95 and 0.81-0.83 for PM2.5 and CO, respectively) between measurements using the sensor packages and those measured by the reference equipment. The study found that the low-cost sensor packages were able to deliver reliable measurements of PM2.5 and CO concentrations. Four low-cost sensor packages were deployed along a short section of an expressway to measure roadside PM2.5 and CO concentrations. The directly measured concentrations were firstly calibrated with the temperature and humidity. The corrected PM2.5 concentrations from each side of the road were different, while the corrected CO concentrations were similar on both sides of the road. Therefore, only the PM2.5 measurements were applied in this study's box model. The assumption of perfect mixing in order for the box model to be applied was shown by the results to be valid to some extent. The PM2.5 emission factors for opposite sides of the road should be calculated separately based on the direction of traffic flow. The PM2.5 emission factors calculated in this study were variable, being impacted by traffic conditions and meteorological conditions. The paper presents a method for obtaining PM2.5 emission factors based on a box model. This method is a promising way of monitoring air pollution in the roadside environment.

Is lymph node dissection necessary for resectable intrahepatic cholangiocarcinoma? A systematic review and meta-analysis.

BACKGROUND: The objective of this meta-analysis was to evaluate the effectiveness and safety of lymph node dissection (LND) in patients with intrahepatic cholangiocarcinoma (ICC). METHODS: A literature search with a date range of January 2000 to January 2018 was performed to identify studies comparing lymph node dissection (LND+) with non-lymph node dissection (LND-) for patients with ICC. The LND + group was further divided into positive (LND + N+) and negative (LND + N-) lymph node status groups based on pathological analysis. RESULTS: 13 studies including 1377 patients were eligible. There were no significant differences in overall survival (OS) (HR 1.13, 95% CI 0.94-1.36; P = 0.20), disease-free survival (DFS) (HR 1.23, 95% CI 0.94-1.60; P = 0.13), or recurrence (OR 1.39, 95% CI 0.90-2.15; P = 0.14) between LND + group and LND-group. Postoperative morbidity was significantly higher in the LND + group (OR 2.67, 95% CI 1.74-4.10; P < 0.001). A subset analysis showed that OS was similar between LND + N- and LND-groups (HR 1.13, 95% CI 0.82-1.56; P = 0.450). However when comparing, OS of the LND-group to the LND+N+ group there was a significant increase in OS for the LND-group (HR 3.26, 95% CI 1.85-5.76; P < 0.001). CONCLUSIONS: LND does not seem to positively affect overall survival and is associated with increased post-operative morbidity.

Fiber-in-Tube Design of Co9 S8 -Carbon/Co9 S8 : Enabling Efficient Sodium Storage.

The sodium-ion battery is a promising battery technology owing to its low price and high abundance of sodium. However, the sluggish kinetics of sodium ion makes it hard to achieve high-rate performance, therefore impairing the power density. In this work, a fiber-in-tube Co9 S8 -carbon(C)/Co9 S8 is designed with fast sodiation kinetics. The experimental and simulation analysis show that the dominating capacitance mechanism for the high Na-ion storage performance is due to abundant grain boundaries, three exposed layer interfaces, and carbon wiring in the design. As a result, the fiber-in-tube hybrid anode shows a high specific capacity of 616 mAh g-1 after 150 cycles at 0.5 A g-1 . At 1 A g-1 , a capacity of ca. 451 mAh g-1 can be achieved after 500 cycles. More importantly, a high energy density of 779 Wh kg-1 and power density of 7793 W kg-1 can be obtained simultaneously.

Negative differential resistance, perfect spin-filtering effect and tunnel magnetoresistance in vanadium-doped zigzag blue phosphorus nanoribbons.

We investigate the electronic and transport properties of vanadium-doped zigzag blue phosphorus nanoribbons by first-principles quantum transport calculations. We study the spin-dependent transport properties and obtain current-voltage curves showing obvious spin polarization and negative differential behaviors. These interesting transport behaviors can be explained by the band structure of the vanadium-doped zigzag blue phosphorus nanoribbons. The tunnel magnetoresistance and spin-filtering effects under different magnetic configurations originate predominately from the symmetry matching between the band structures of the electrodes. According to our results, vanadium-doped zigzag blue phosphorus nanoribbons can be used as a perfect spin filter with a large tunnel magnetoresistance. This also indicates that blue phosphorus nanoribbons are a promising candidate for their future application in spintronics.

Half-metallic and magnetic semiconducting behaviors of metal-doped blue phosphorus nanoribbons from first-principles calculations.

We investigate the electronic and magnetic properties of substitutional metal atom impurities in two-dimensional (2D) blue phosphorene nanoribbons using first-principles calculations. In impure zigzag blue phosphorene nanoribbons (zBPNRs), a metal atom substitutes for a P atom at position "A/B". The V-"B"structure shows half-metallic properties, while the Mn-"A/B", V-"A", Fe-"B", and Cr-"A/B" structures show magnetic semiconductor properties. In addition, the Fe-"A" system shows magnetic metallic properties. On the other hand, for metal-doped armchair blue phosphorene nanoribbons (aBPNRs), the Mn-"A/B", V-"A", Fe-"A/B", and Cr-"A/B" structures show magnetic semiconductor properties, while the V-"B" structure shows nonmagnetic properties. We find that the magnetic properties of such substitutional impurities can be understood by regarding the exchange splitting of the metal 3d orbitals. And from analyzing the electron orbitals, we conclude that the main contribution of the DOS for every system comes from the d and p orbitals. These results suggest excellent candidates for new magnetic semiconductors and half-metals for spintronic devices based on blue phosphorenes.

Giant magnetoresistance in zigzag MoS2 nanoribbons.

Using first principles calculations based on density functional theory, we investigated the transport properties of zigzag MoS2 nanoribbons with parallel and antiparallel spin configurations. The results show that the parallel configuration has conventional metallic properties while the antiparallel configuration presents semiconductor properties. Consequently, the conduction calculations predict that the zigzag MoS2 nanoribbons exhibit the giant magnetoresistance effect with a value over four orders of magnitude at room temperature by altering the configuration from the parallel to the antiparallel spin junction. By analyzing the spin-resolved band structures of zigzag MoS2 nanoribbons, we clarify that the orbital mismatching near the Fermi level between spin up and spin down is a key factor to generate this large magnetoresistance. Our results indicate that the giant magnetoresistance effect in the zigzag MoS2 nanoribbons remains robust to the change in the ribbon widths and lengths.

A first principles study of novel one-dimensional organic half-metal vanadium-cyclooctatetraene wire.

The structural, electronic, and magnetic properties of one-dimensional vanadium-cyclooctatetraene[(V-COT)]∞ wire and sandwich clusters are investigated by means of density functional theory. It is found that the (V-COT)∞ SMW is half-metallic. Through the spin transportation calculations, the system for V-COT clusters coupled to gold electrodes performs nearly perfect spin filters. In addition, the I-V curve shows obviously negative differential resistance effects. These results suggest the potential applications of (V-COT)∞ in spintronics.

Adaptive correction method of hybrid aberrations in Fourier ptychographic microscopy.

Significance: Fourier ptychographic microscopy (FPM) enables quantitative phase imaging with a large field-of-view and high resolution by acquiring a series of low-resolution intensity images corresponding to different spatial frequencies stitched together in the Fourier domain. However, the presence of various aberrations in an imaging system can significantly degrade the quality of reconstruction results. The imaging performance and efficiency of the existing embedded optical pupil function recovery (EPRY-FPM) aberration correction algorithm are low due to the optimization strategy. Aim: An aberration correction method (AA-P algorithm) based on an improved phase recovery strategy is proposed to improve the reconstruction image quality. Approach: This algorithm uses adaptive modulation factors, which are added while updating iterations to optimize the spectral function and optical pupil function updates of the samples, respectively. The effectiveness of the proposed algorithm is verified through simulations and experiments using an open-source biological sample dataset. Results: Experimental results show that the proposed AA-P algorithm in an optical system with hybrid aberrations, recovered complex amplitude images with clearer contours and higher phase contrast. The image reconstruction quality was improved by 82.6% when compared with the EPRY-FPM algorithm. Conclusions: The proposed AA-P algorithm can reconstruct better results with faster convergence, and the recovered optical pupil function can better characterize the aberration of the imaging system. Thus, our method is expected to reduce the strict requirements of wavefront aberration for the current FPM.

GPX2 is a potential therapeutic target to induce cell apoptosis in lenvatinib against hepatocellular carcinoma.

INTRODUCTION: Lenvatinib has recently become available as the first-line therapy for advanced hepatocellular carcinoma (HCC), but its molecular mechanism in HCC remains largely unknown. OBJECTIVES: The current study aims to identify the molecular mechanisms of lenvatinib in HCC. METHODS: Gene expression microarrays, flow cytometry, western blot, qRT-PCR, immunohistochemistry and immunofluorescence were used to study the response of HCC cells to lenvatinib. Xenograft tumor of Huh7 cells was also established to detect the effect of lenvatinib in vivo. RESULTS: Herein, we found that lenvatinib could induce apoptosis via increasing reactive oxygen species (ROS) levels in HCC cells. Then, microarray analysis and qRT-PCR results confirmed that GPX2 was a vital target for lenvatinib against HCC. Loss and gain function of experiment showed that regulating GPX2 levels markedly affected the lenvatinib-induced ROS levels and apoptosis in HCC cells. In addition, analyses of The Cancer Genome Atlas database and the qRT-PCR results in our cohort both showed that GPX2 markedly overexpressed in tumor tissues and correlated with poor overall survival in HCC. Mechanistically, our findings further demonstrated that GPX2 was a downstream gene regulated by ß-catenin, while lenvatinib could prevent nuclear translocation of ß-catenin and further inhibit GPX2 expression in HCC cells. More importantly, the correlation of GPX2 expression with lenvatinib response was further analyzed in 22 HCC patients who received lenvatinib therapy, and the results showed that the objective response rate (ORR) in patients with low GPX2 expression was 44.4% (4/9), while the ORR in patients with high GPX2 levels was only 7.7% (1/13). CONCLUSION: Our findings indicated that GPX2 plays an important role in lenvatinib-induced HCC cell apoptosis, which might serve as a biomarker for instruction of lenvatinib therapy in HCC patients.

Quasi-2D Mn3Si2Te6 Nanosheet for Ultrafast Photonics.

The magnetic nanomaterial Mn3Si2Te6 is a promising option for spin-dependent electronic and magneto-optoelectronic devices. However, its application in nonlinear optics remains fanciful. Here, we demonstrate a pulsed Er-doped fiber laser (EDFL) based on a novel quasi-2D Mn3Si2Te6 saturable absorber (SA) with low pump power at 1.5 µm. The high-quality Mn3Si2Te6 crystals were synthesized by the self-flux method, and the ultrathin Mn3Si2Te6 nanoflakes were prepared by a simple mechanical exfoliation procedure. To the best of our knowledge, this is the first time laser pulses have been generated using quasi-2D Mn3Si2Te6. A stable pulsed laser at 1562 nm with a low threshold pump power of 60 mW was produced by integrating the Mn3Si2Te6 SA into an EDFL cavity. The maximum power of the output pulse is 783 µW. The repetition rate can vary from 24.16 to 44.44 kHz, with corresponding pulse durations of 5.64 to 3.41 µs. Our results indicate that the quasi-2D Mn3Si2Te6 is a promising material for application in ultrafast photonics.

Reduction in required volume of imaging data and image reconstruction time for adaptive-illumination Fourier ptychographic microscopy.

Fourier ptychographic microscopy (FPM) is a promising super-resolution computational imaging technology. It stitches a series of low-resolution (LR) images in the Fourier domain by an iterative method. Thus, it obtains a large field of view and high-resolution quantitative phase images. Owing to its capability to perform high-spatial bandwidth product imaging, FPM is widely used in the reconstruction of conventional static samples. However, the influence of the FPM imaging mechanism limits its application in high-speed dynamic imaging. To solve this problem, an adaptive-illumination FPM scheme using regional energy estimation is proposed. Starting with several captured real LR images, the energy distribution of all LR images is estimated, and select the measurement images with large information to perform FPM reconstruction. Simulation and experimental results show that the method produces efficient imaging performance and reduces the required volume of data to more than 65% while ensuring the quality of FPM reconstruction.