Tunable and giant valley-selective Hall effect in gapped bilayer graphene

Berry curvature is analogous to magnetic field but in momentum space and is commonly present in materials with non-trivial quantum geometry. It endows Bloch electrons with transverse anomalous velocities to produce Hall-like currents even in the absence of a magnetic field. We report the direct observation of in situ tunable valley-selective Hall effect (VSHE), where inversion symmetry, and thus the geometric phase of electrons, is controllable by an out-of-plane electric field. We use high-quality bilayer graphene with an intrinsic and tunable bandgap, illuminated by circularly polarized mid-infrared light and confirm that the observed Hall voltage arises from an optically-induced valley population. Compared with molybdenum disulfide, we find orders of magnitude larger VSHE, attributed to the inverse scaling of the Berry curvature with bandgap. By monitoring the valley-selective Hall conductivity, we study Berry curvature's evolution with bandgap. This in situ manipulation of VSHE paves the way for topological and quantum geometric opto-electronic devices, such as more robust switches and detectors

Angiopoietin-2 impairs collateral artery growth associated with the suppression of the infiltration of macrophages in mouse hindlimb ischaemia

Abstract Background Angiopoietin-2 (Ang-2), a ligand of the Tie-2 receptor, plays an important role in maintaining endothelial cells and in destabilizing blood vessels. Collateral artery growth (arteriogenesis) is a key adaptive response to arterial occlusion. It is unknown whether the destabilization of blood vessels by Ang-2 can affect arteriogenesis and modulate mononuclear cell function. This study aimed to investigate the effects of Ang-2 on collateral artery growth. Methods Hindlimb ischaemia model was produced in C57BL/6 mice by femoral artery ligation. Blood flow perfusion was measured using a laser Doppler perfusion imager quantitative RT-PCR analysis was applied to identify the level of angiogenic factors. Results After the induction of hindlimb ischaemia, blood flow recovery was impaired in mice treated with recombinant Ang-2 protein; this was accompanied by a reduction of peri-collateral macrophage infiltration. In addition, quantitative RT-PCR analysis revealed that Ang-2 treatment decreased monocyte chemotactic protein-1 (MCP-1), platelet-derived growth factor-BB (PDGF-BB) mRNA levels in ischaemic adductor muscles. Ang-2 can lead to macrophage M1/M2 polarization shift inhibition in the ischaemic muscles. Furthermore, Ang-2 reduced the in vitro inflammatory response in macrophages and vascular cells involved in arteriogenesis. Conclusions Our results demonstrate that Ang-2 is essential for efficient arteriogenesis, which controls macrophage infiltration

The Dust Attenuation Scaling Relation of Star-Forming Galaxies in the EAGLE Simulations

Dust attenuation in star-forming galaxies (SFGs), as parameterized by the infrared excess (IRX $\equiv L_{\rm IR}/L_{\rm UV}$), is found to be tightly correlated with star formation rate (SFR), metallicity and galaxy size, following a universal IRX relation up to $z=3$. This scaling relation can provide a fundamental constraint for theoretical models to reconcile galaxy star formation, chemical enrichment, and structural evolution across cosmic time. We attempt to reproduce the universal IRX relation over $0.1\leq z\leq 2.5$ using the EAGLE hydrodynamical simulations and examine sensitive parameters in determining galaxy dust attenuation. Our findings show that while the predicted universal IRX relation from EAGLE approximately aligns with observations at $z\leq 0.5$, noticeable disparities arise at different stellar masses and higher redshifts. Specifically, we investigate how modifying various galaxy parameters can affect the predicted universal IRX relation in comparison to the observed data. We demonstrate that the simulated gas-phase metallicity is the critical quantity for the shape of the predicted universal IRX relation. We find that the influence of the infrared luminosity and infrared excess is less important while galaxy size has virtually no significant effect. Overall, the EAGLE simulations are not able to replicate some of the observed characteristics between IRX and galaxy parameters of SFGs, emphasizing the need for further investigation and testing for our current state-of-the-art theoretical models.Comment: 19 pages, 15 figures, accepted for publication in MNRA

Key technologies of fully autonomous drilling system for coal mine anti-impact drilling robot

For the technical problem of low intelligence in the process of drilling and pressure relief in high stress mines, the research status of pressure relief technology and equipment at home and abroad is summarized and analyzed in this study. It is pointed out that the development of high-performance, highly reliable, and efficient fully autonomous drilling system of anti-impact drilling robot is an important development direction to solve the problem of rock burst prevention and control. To this end, the five key technologies that affect the performance of the drilling system, namely “the precise recognition of hole position, the precise perception of drilling tool posture, the wireless electromagnetic intelligent detection, the intelligent recognition of drilling tool operation status, and the precise control of the drilling system” have been summarized, and the solutions and methods have been provided. In response to the problem of accurate identification of pressure relief holes in complex and harsh environments, a SinGAN model for pressure relief hole image sample expansion is developed, which integrates image size adjustment and multi-stage training modes. The Faster RCNN optimized by multi-layer feature fusion is introduced, and a hole position recognition model based on an improved SqueezeNet lightweight network architecture is constructed to achieve an accurate and fast recognition of pressure relief hole positions. To address the issue of precise perception of drilling tool posture, the unscented Kalman filter optimized by improved gradient descent algorithm is designed for the initial alignment of Inertial Measurement Unit (IMU). Multiple IMU spatial array layouts are designed, and a BP neural network-based compensation method for drilling tool posture error is studied, aiming to improve the accuracy of drilling tool posture calculation and achieve a precise drilling pressure relief. Aiming at the precise detection of drilling conditions in complex geological environments, a wireless elec-tromagnetic transmission system architecture for underground measurement while drilling in coal mines has been established. The principles of adaptive modulation of weak electromagnetic wave signals and high-speed bidirec-tional electromagnetic transmission technology have been explored, and the measurement principles and imple-mentation processes of geological parameters, geological parameters, and engineering parameters at the bottom of the hole have been investigated. To address the issue of identifying the operational status of drilling systems, a multi-domain feature extraction architecture for drilling signals in the time domain, frequency domain, and time frequency domain, as well as a deep network advanced feature extraction architecture, have been constructed. In addition, the key component health status assessment and fault diagnosis techniques for drilling systems have been proposed, and a prediction model for sticking risk factors based on an improved bat optimized long-term and short-term memory network has been built to accurately predict the stuck status of pressure relief drilling tools. In terms of the issue of precise control of drilling systems, the working principle of the hydraulic system of the drilling system is analyzed, and a precise control scheme for the drilling system considering the characteristics of coal and rock is formulated. The principle of solving the optimal control parameters of the drilling system based on torque and position is explored, aiming to achieve intelligent collaborative control and parallel operation of the drilling return system and feed system

The Physical Properties of Star-Forming Galaxies with Strong [O III] Lines at z=3.25

We present an analysis of physical properties of 34 [O III] emission-line galaxies (ELGs) at z=3.254$\pm$0.029 in the Extended Chandra Deep Field South (ECDFS). These ELGs are selected from deep narrow H2S(1) and broad Ks imaging of 383 arcmin$^{2}$ obtained with CFHT/WIRCam. We construct spectral energy distributions (SEDs) from U to Ks to derive the physical properties of ELGs. These [O III] ELGs are identified as starburst galaxies with strong [O III] lines of L([O III]) ~ 10$^{42.6}$ - 10$^{44.2}$ erg s$^{-1}$, and have stellar masses of M* ~ 10$^{9.0}$-10$^{10.6}$ M$_\odot$ and star formation rates of ~ 10-210 M$_\odot$ yr$^{-1}$. Our results show that 24% of our sample galaxies are dusty with Av > 1 mag and EW(OIII)$_{rest}$ ~ 70-500 $\AA$, which are often missed in optically selected [O III] ELG samples. Their rest-frame UV and optical morphologies from HST/ACS and HST/WFC3 deep imaging reveal that these [O III] ELGs are mostly multiple-component systems (likely mergers) or compact. And 20% of them are nearly invisible in the rest-frame UV owing to heavy dust attenuation. Interestingly, we find that our samples reside in an overdensity consisting of two components: one southeast (SE) with an overdensity factor of $\delta_{gal}$ ~ 41 over a volume of 13$^{3}$ cMpc$^{3}$ and the other northwest (NW) with $\delta_{gal}$ ~ 38 over a volume of 10$^{3}$ cMpc$^{3}$. The two overdense substructures are expected to be virialized at z=0 with a total mass of ~ 1.1 x 10$^{15}$ M$_\odot$ and ~ 4.8 x 10$^{14}$ M$_\odot$, and probably merge into a Coma-like galaxy cluster.Comment: 22 pages, 11 figures, 3 tables. Accepted for publication in Ap

Effect of single-patient room design on the incidence of nosocomial infection in the intensive care unit: a systematic review and meta-analysis

BackgroundPrevious studies have yielded varying conclusions regarding the impact of single-patient room design on nosocomial infection in the intensive care unit (ICU). We aimed to examine the impact of ICU single-patient room design on infection control.MethodsWe conducted a comprehensive search of PubMed, Embase, the Cochrane Library, Web of Science, CNKI, WanFang Data, and CBM databases from inception to October 2023, without language restrictions. We included observational cohort and quasi-experimental studies assessing the effect of single- versus multi-patient rooms on infection control in the ICU. Outcomes measured included the nosocomial infection rate, incidence density of nosocomial infection, nosocomial colonization and infection rate, acquisition rate of multidrug-resistant organisms (MDROs), and nosocomial bacteremia rate. The choice of effect model was determined by heterogeneity.ResultsOur final analysis incorporated 12 studies involving 12,719 patients. Compared with multi-patient rooms in the ICU, single-patient rooms demonstrated a significant benefit in reducing the nosocomial infection rate (odds ratio [OR]: 0.68; 95% confidence interval [CI]: 0.59, 0.79; p < 0.00001). Analysis based on nosocomial infection incidence density revealed a statistically significant reduction in single-patient rooms (OR: 0.64; 95% CI: 0.44, 0.92; p = 0.02). Single-patient rooms were associated with a marked decrease in nosocomial colonization and infection rate (OR: 0.44; 95% CI: 0.32, 0.62; p < 0.00001). Furthermore, patients in single-patient rooms experienced lower nosocomial bacteremia rate (OR: 0.73; 95% CI: 0.59, 0.89; p = 0.002) and lower acquisition rate of MDROs (OR: 0.41; 95% CI: 0.23, 0.73; p = 0.002) than those in multi-patient rooms.ConclusionImplementation of single-patient rooms represents an effective strategy for reducing nosocomial infections in the ICU.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/)