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This study aimed to explore the effects of peroxisome proliferator-activated receptor α (PPAR-α), a known inhibitor of ferroptosis, in Myocardial ischemia/reperfusion injury (MIRI) and its related mechanisms. In vivo and in vitro MIRI models were established. Our results showed that activation of PPAR-α decreased the size of the myocardial infarct, maintained cardiac function, and decreased the serum contents of creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), and Fe2+ in ischemia/reperfusion (I/R)-treated mice. Additionally, the results of H&E staining, DHE staining, TUNEL staining, and transmission electron microscopy demonstrated that activation of PPAR-α inhibited MIRI-induced heart tissue and mitochondrial damage. It was also found that activation of PPAR-α attenuated MIRI-induced ferroptosis as shown by a reduction in malondialdehyde, total iron, and reactive oxygen species (ROS). In vitro experiments showed that intracellular contents of malondialdehyde, total iron, LDH, reactive oxygen species (ROS), lipid ROS, oxidized glutathione disulphide (GSSG), and Fe2+ were reduced by the activation of PPAR-α in H9c2 cells treated with anoxia/reoxygenation (A/R), while the cell viability and GSH were increased after PPAR-α activation. Additionally, changes in protein levels of the ferroptosis marker further confirmed the beneficial effects of PPAR-α activation on MIRI-induced ferroptosis. Moreover, the results of immunofluorescence and dual-luciferase reporter assay revealed that PPAR-α achieved its activity via binding to the 14-3-3η promoter, promoting its expression level. Moreover, the cardioprotective effects of PPAR-α could be canceled by pAd/14-3-3η-shRNA or Compound C11 (14-3-3η inhibitor). In conclusion, our results indicated that ferroptosis plays a key role in aggravating MIRI, and PPAR-α/14-3-3η pathway-mediated ferroptosis and mitochondrial injury might be an effective therapeutic target against MIRI. [ABSTRACT FROM AUTHOR]

Regulation of phase structure has been recognized as one of the most effective ways to fabricate self-healing polymers with high mechanical strength. The mechanical properties of the resultant polymers are certainly affected by the size of separated phase domain. However, the study on this aspect is absence, because it can hardly exclude the influence of variation in monomer proportion required for tuning the separated phase size. Here, we report the first study on tuning the phase size through reversible addition-fragmentation chain transfer (RAFT) polymerization without changing the proportion of monomers. As expected, the size of separated phase has been successfully mediated from 15 nm to 9 nm by tuning the molecular weight of the chain transfer agent. It is found that the mechanical strength and the self-healing efficiency of the resultant polymers increase simultaneously with the decrease of phase size. The study on the formation kinetics of hydrogen bonds reveals that the decrease of phase size can facilitate the re-bonding rate of hydrogen bonds, even if the migration of polymer chains is restricted. [ABSTRACT FROM AUTHOR]

Sleep stage classification is a necessary step for diagnosing sleep disorders. Generally, experts use traditional methods based on every 30 seconds (s) of the biological signals, such as electrooculograms (EOGs), electrocardiograms (ECGs), electromyograms (EMGs), and electroencephalograms (EEGs), to classify sleep stages. Recently, various state-of-the-art approaches based on a deep learning model have been demonstrated to have efficient and accurate outcomes in sleep stage classification. In this paper, a novel deep convolutional neural network (CNN) combined with a long short-time memory (LSTM) model is proposed for sleep scoring tasks. A key frequency domain feature named Mel-frequency Cepstral Coefficient (MFCC) is extracted from EEG and EMG signals. The proposed method can learn features from frequency domains on different bio-signal channels. It firstly extracts the MFCC features from multi-channel signals, and then inputs them to several convolutional layers and an LSTM layer. Secondly, the learned representations are fed to a fully connected layer and a softmax classifier for sleep stage classification. The experiments are conducted on two widely used sleep datasets, Sleep Heart Health Study (SHHS) and Vincent's University Hospital/University College Dublin Sleep Apnoea (UCDDB) to test the effectiveness of the method. The results of this study indicate that the model can perform well in the classification of sleep stages using the features of the 2-dimensional (2D) MFCC feature. The advantage of using the feature is that it can be used to input a two-dimensional data stream, which can be used to retain information about each sleep stage. Using 2D data streams can reduce the time it takes to retrieve the data from the one-dimensional stream. Another advantage of this method is that it eliminates the need for deep layers, which can help improve the performance of the model. For instance, by reducing the number of layers, our seven layers of the model structure takes around 400 s to train and test 100 subjects in the SHHS1 dataset. Its best accuracy and Cohen's kappa are 82.35% and 0.75 for the SHHS dataset, and 73.07% and 0.63 for the UCDDB dataset, respectively. [ABSTRACT FROM AUTHOR]

The stability of coal pillar is extremely important to the control of rock strata movement and surface subsidence. It is of great significance for mining design to analyze the stability and failure characteristics of coal and rock pillars left after mining and to study the failure characteristics and rheological properties of coal and rock with different shapes. In this paper, based on uniaxial compression and rheological tests on rock samples, the rheological properties of rock samples with different shapes were discussed by using the nonlinear theoretical mechanics and damage theory, and the rheological mechanical characteristics of coarse yellow sandstone samples under the action of different free surface areas and the same loading contact area were investigated by means of experimental research, theoretical analysis and numerical simulation. The following conclusions were drawn: the failure characteristics and dynamic change process of rock samples with different shapes under the same loading contact area are obtained by uniaxial compression test and multi-stage rheological loading. The uniaxial compressive strengths of rock samples with the same loading contact surface area and different free surface areas are inversely proportional to their free surface areas. For the round sample, the stress level in the rheological test is obviously lower than the instantaneous peak uniaxial compression strength, while for the other samples, the stress level in the rheological test is close to the instantaneous peak uniaxial compression strength. For rock all these samples, both the ratio of steady-state rheological time to final failure time and the deformation degree decrease with the increase of free surface area. [ABSTRACT FROM AUTHOR]

Transcranial focused ultrasound stimulation is a promising brain stimulation technique for its noninvasiveness and higher spatial resolutions and is used for various neuromodulation applications. As the skull is the primary barrier to delivering ultrasound to the deep brain region, it induces unpredictable ultrasound exposure. The objective of the study is to design customised transducers and assess the effects of the skull on ultrasound wave propagation. Computational skull models were constructed using computerised tomography scans. A full-wave finite-difference time-domain simulation platform, Sim4Life, was then used to design and simulate ultrasound wave propagation. In addition, the impacts of the skull were assessed through sensitivity analysis in the intracranial intensity, pressure, full width at half maximum, and energy deposition. Compared to the intracranial intensity distribution when the transducer is placed over the top area of the skull, the peak intensity increased by 23.4% for transmission through the temporal window. The temporal window, the thinnest part of the skull, provides a site for intracranial peak intensity and optimal focal spot area using focused ultrasound. The numerical investigation in this study provided a guideline for targeting and dosing, accounting for and lessening variability in studies addressing transcranial focused ultrasound applications. [ABSTRACT FROM AUTHOR]

Schizophrenia is a severe mental illness which can cause lifelong disability. Most recent studies on the Electroencephalogram (EEG)-based diagnosis of schizophrenia rely on bespoke/hand-crafted feature extraction techniques. Traditional manual feature extraction methods are time-consuming, imprecise, and have a limited ability to balance accuracy and efficiency. Addressing this issue, this study introduces a deep residual network (deep ResNet) based feature extraction design that can automatically extract representative features from EEG signal data for identifying schizophrenia. This proposed method consists of three stages: signal pre-processing by average filtering method, extraction of hidden patterns of EEG signals by deep ResNet, and classification of schizophrenia by softmax layer. To assess the performance of the obtained deep features, ResNet softmax classifier and also several machine learning (ML) techniques are applied on the same feature set. The experimental results for a Kaggle schizophrenia EEG dataset show that the deep features with support vector machine classifier could achieve the highest performances (99.23% accuracy) compared to the ResNet classifier. Furthermore, the proposed model performs better than the existing approaches. The findings suggest that our proposed strategy has capability to discover important biomarkers for automatic diagnosis of schizophrenia from EEG, which will aid in the development of a computer assisted diagnostic system by specialists. [ABSTRACT FROM AUTHOR]

To study the influence mechanism of gangue backfilling material (GBM) with different particle sizes on overburden deformation, the particle movement characteristics and the mechanism of stiffness difference with different particle sizes of GBM were analysed by physical compression and particle flow numerical simulations. Then, combined with a similar material simulation method, the deformation characteristics of roof overburden and the evolution process of floor stress in backfill mining with backfilling bodies of different stiffness levels were studied. The results indicate that the subsidence decreased monotonously with a decrease in the particle size, and the stiffness of the GBM increased significantly under the same vertical load. The small-particle gangue moved downward in the layered law under the same load conditions, while the large-particle gangue moved downward through rotation, rubbing, crushing, and filling interaction processes. In the treatment of goaf by the backfilling method, the entire process of overlying strata movement mainly experienced bending, micro-fracture, separation, compaction, and new fracture, and the anti-deformation capacity of the backfilling body directly determined the deformation and movement of the overburden strata in a goaf. In the backfilling method, the greater the stiffness of the filling body, the smaller the advanced support pressure, and the more effective it was to inhibit pressure relief from the floor. [ABSTRACT FROM AUTHOR]

Through neodymium-mediated coordinative chain transfer copolymerizaiton (CCTcoP), polyisoprenes bearing dual hydroxylated mini-blocky chain-ends were prepared via a three-step strategy. Kinetic studies revealed that, the polymerization demonstrated typical features of CCTcoP across the whole polymerization process, i.e., quasi-living polymerization characteristic, tunable molecular weights, narrow molecular weight distributions, and atom economies. Comparing to previously reported CCTP homopolymerization systems, the presence of oxygen-containing IpOAl polar comonomer slowed down chain transfer rates obviously, rendering slightly higher molecular weights of the resultant PIps and smaller Np (number of polymer chains per Nd atom) values. Moreover, to mimic the structure of natural rubber, the hydroxyl end groups can be facilely modified into phosphonate, amide, and UPy, whose structures were further confirmed by NMR spectra. Incorporation these functionalities could greatly improve the hydrophilic properties of the polymers, as revealed from the significantly reduced static water contact angles. [ABSTRACT FROM AUTHOR]

Key summary points: Aim: To evaluate the association between hemoglobin concentration at admission and mortality of older patients with hip fractures. Findings: The hemoglobin at admission was nonlinearly associated with mortality of older patients with hip fractures, and hemoglobin at admission < 9.8 g/dL was a risk predictor of 3-year mortality. Message: The hemoglobin level at admission is an essential predictive indicator, and this study provides implications for clinical practice of evaluating hemoglobin at admission for hip fractures. Background: Hip fracture patients often have a large drop in hemoglobin (Hgb) concentration that is associated with the initial trauma. However, there is no study of a correlation between Hgb concentration at admission and short-term mortality. Thus, we evaluated a possible linear and nonlinear association between Hgb and mortalityfor older patients with hip fracture. Methods: Consecutive older patients who had hip fractures were screened between January 2015 and September 2019. Demographic and clinical characteristics were collected. Linear and nonlinear multivariate Cox regression models were used to identify association between Hgb at admission and mortality. All analyses were performed with EmpowerStats and R software. Results: Two thousand five hundred eighty-nine patients were included in the study. There were 849 men and 1740 women. The mean age was 79.6 ± 6.8 years. The mean follow-up was 39.0 months. Nine hundred seven (35.0%) patients died for all-cause reasons. The mean Hgb at admission was 11.07 ± 1.95 g/dL. Linear multivariate Cox regression models showed Hgb at admission was associated with mortality ([Hazard Ratio] HR 0.91, 95% CI 0.87–0.95, P < 0.0001) after adjusting for confounding factors. However, the linear association was unstable, and nonlinearity was found between Hgb at admission and mortality. The Hgb concentration of 9.8 g/dL was an inflection point. A Hgb at admission < 9.8 g/dL was associated with mortality (HR 0.81, 95% CI 0.74–0.89, P < 0.0001), whereas > 9.8 g/dL was not a risk factor for mortality (HR 0.98, 95% CI 0.92–1.04, P = 0.4730). Conclusions: The Hgb concentration at admission was nonlinearly associated with mortality of older patients with hip fracture, and Hgb at admission < 9.8 g/dL was a risk predictor of 3-year mortality. Research registration: ChiCTR2200057323 [ABSTRACT FROM AUTHOR]

In this work, (Bi, Pb)2Sr2Ca2Cu3O10+δ superconducting nano-network was successfully synthesized based on liquid-phase method via electrospinning and followed calcinations. The effect of plumbum (Pb) replacing bismuth (Bi) and the superconductivity of Bi2-xPbxSr2Ca2Cu3O10+δ (x = 0, 0.1, 0.2, 0.3, 0.4, and 0.45) nano-networks were studied. With the increase of the ratio of Pb, it was found that the relative volume fraction of the Bi-2223 phase increased from 53.50 to 93.98%, the pinning force increased from 0.66 × 108 N m−3 to 3.22 × 108 N m−3, and the critical current density increased from 0.98 × 108 A m−2 to 4.71 × 108 A m−2. By fitting the dominant magnetic flux pinning mechanism, it was also found that the addition of Pb can improve the pinning center of Bi-2223 phase. These results indicate that the addition of Pb is beneficial to improve the fraction of superconducting Bi-2223 phase. The optimal superconductor pinning structure has been obtained because the pinning centers are created by substituting Pb for Bi. [ABSTRACT FROM AUTHOR]

In this paper, we consider a underwater wireless sensor network, which is composed of an autonomous underwater vehicle (AUV) and the underwater data collection stations. Constrained by limited resources, at each decision epoch the AUV selects one underwater data collection station to update the data and then uploads it to the surface base station. Different from other underwater communication models, we consider the influence of underwater environment on the AUV and develop an AUV model with random lifetime, meanwhile, we further propose that the information arrives randomly with different importance levels. The system model is formulated into a discounted Markov decision process with infinite horizon. Taking the age of information and the importance of information as the performance metrics, the optimal scheduling strategy of the AUV is developed, and the threshold structure characteristics of the optimal strategy are proved. Finally, the numerical examples are given to illustrate the theoretical results, and the impacts of system parameters on the optimal strategy and the value function are also investigated. [ABSTRACT FROM AUTHOR]

A family of highly bulky bis(salicylaldiminate) Co(II) complexes bearing cavity-like conformations are disclosed herein. Due to their unique bulky nature around the cobalt atoms that are reflected from space-filling models and the buried volume percentages, obviously longer bond distances of Co-N and Co-O are revealed from those complexes. Moreover, because of these well-protected active species, the cobalt complexes are able to catalyze 1,3-butadiene polymerization in high yields at extreme low catalyst concentrations, revealing a ultra high catalytic efficiency. At a ratio of 50000, all the complexes can afford polybutadiene with yields higher than 90%. Furthermore, the highly steric bulkiness of the ligand can also significantly enhance the thermostability of the active species. At temperature of 80–120 °C, the complexes are able to successfully maintain high activities, giving polymer yields up to 90%. [ABSTRACT FROM AUTHOR]

In this work, we compared Bi2Sr2CaCu2O8+θ (BSCCO) superconducting nanofibers prepared by electrospinning (ES) and solution blowing spinning (SBS) techniques for the first time. The differences in microstructure and magnetic properties of BSCCO superconducting fibers prepared by ES and SBS were investigated. The thickness of the ES-BSCCO nanofibers was more uniform than that of the SBS-BSCCO nanofibers. In addition, the superconducting transition temperature of superconducting SBS-BSCCO nanofibers was only 73.5 K due to the weak connection of grains, which was lower than 82.5 K of the ES-BSCCO sample. Further studies showed the area enclosed by the hysteresis loop, the critical current density, and the intensity of the pinning force of SBS-BSCCO fibers were all smaller than those of the ES-BSCCO sample. Finally, we found that the pinning mechanism of these two BSCCO samples could be ascribed to the activation of the point-pinning mechanism and surface-pinning mechanism. [ABSTRACT FROM AUTHOR]

This work reports the superior properties of flexible multi-functional composite fibers based on graphene aerogel fibers. With the addition of phase change materials, the graphene aerogel fibers were synthesized by wet spinning and supercritical drying. The phase change materials can improve the structural uniformity and thermal stability of the composite fibers. The fibers coated with polydimethylsiloxane and fluorocarbon can respond to various external stimuli (e.g., electrons, photons, and heat), as well as have excellent properties of shape compliance, self-cleaning, and insulated surfaces. After coating fluorocarbon, the maximum water contact angle of graphene aerogel fibers increases from 132.18° to 151.77°. It is worth mentioning that adding an insulation layer of polydimethylsiloxane avoids the high-temperature problem caused by the short circuit of graphene aerogel fibers. The short-circuit temperature of graphene aerogel fibers is as high as 65 °C, while that of the composite fiber is only 41.5 °C after coating with polydimethylsiloxane. The temperature of graphene aerogel fibers with polyethylene glycol can increase to 39.3 °C under simulated sunlight. In addition, graphene aerogel fibers have excellent electrical conductivity (4.85 × 103 S m−1) at 300 K. After coating with polyethylene glycol, its electrical conductivity is still as high as 2.95 × 103 S m−1. The good electrical conductivity makes the aerogel fibers have promising application in advanced wearable systems. [ABSTRACT FROM AUTHOR]

The repair of critical diaphyseal defects of lower weight-bearing limbs is an intractable problem in clinical practice. From December 2017, we prospectively applied 3D printed porous Ti6Al4V scaffolds to reconstruct this kind of bone defect. All patients experienced a two-stage surgical process, including thorough debridement and scaffold implantation. With an average follow-up of 23.0 months, ten patients with 11 parts of bone defects were enrolled in this study. The case series included three females and seven males, their defect reasons included seven parts of osteomyelitis and four parts of aseptic nonunion. The bone defects located at femur (five parts) and tibia (six parts), with an average defect distance of 12.2 cm. Serial postoperative radiologic follow-ups displayed a continuous process of new bone growing and remodeling around the scaffold. One patient suffered tibial varus deformity, and he underwent a revision surgery. The other nine patients achieved scaffold stability. No scaffold breakage occurred. In conclusion, the implantation of 3D printed Ti6Al4V scaffold was feasible and effective to reconstruct critical bone defects of lower limbs without additional bone grafting. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Multiscale architecture design of 3D printed biodegradable Zn-based porous scaffolds for immunomodulatory osteogenesis" published in Nature Communications. The correction addresses an error in Figure 4 of the original article, where two identical graphs were mistakenly included. The correct version of Figure 4 has been updated in both the PDF and HTML versions of the article. The authors of the article are Shuang Li, Hongtao Yang, Xinhua Qu, Yu Qin, Aobo Liu, Guo Bao, He Huang, Chaoyang Sun, Jiabao Dai, Junlong Tan, Jiahui Shi, Yan Guan, Wei Pan, Xuenan Gu, Bo Jia, Peng Wen, Xiaogang Wang, and Yufeng Zheng. [Extracted from the article]

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In this paper, we develop a novel stochastic model, i.e., an extended two-dimensional stochastic fluid model (2D-SFM), to describe the video streaming system over the IP network dynamics. We first derive two Laplace–Stieltjes transform (LST) matrices of the 2D-SFM, based on which two key performance metrics of the video streaming system, i.e., the video freeze probability and the moment of the buffering delay are derived, in particular, the expectation and the variance of the buffering delay are obtained. As an application, we develop an algorithm to find the optimal initial buffering level with the constraint that the freeze probability is below a given tolerable probability. Finally, numerical results and simulations are provided to corroborate the theoretical findings, and the effects of the system parameters in different scenarios on system performance metrics are further studied numerically. [ABSTRACT FROM AUTHOR]

Background: Extracellular vesicles (EVs) contain thousands of proteins and nucleic acids, playing an important role in cell–cell communications. Sertoli cells have been essential in the testis as a "nurse cell". However, EVs derived from human Sertoli cells (HSerCs) have not been well investigated. Methods: EVs were isolated from HSerCs via ultracentrifugation and characterized by transmission electron microscopy, tunable resistive pulse sensing, and Western blotting. The cargo carried by HSerCs-EVs was measured via liquid chromatography-mass spectrometry and GeneChip miRNA Arrays. Bioinformatic analysis was performed to reveal potential functions of HSerCs-EVs. Results: A total of 860 proteins with no less than 2 unique peptides and 88 microRNAs with high signal values were identified in HSerCs-EVs. Biological processes related to molecular binding, enzyme activity, and regulation of cell cycle were significantly enriched. Specifically, many proteins in HSerCs-EVs were associated with spermatogenesis and regulation of immune system, including Septins, Large proline-rich protein BAG6, Clusterin, and Galectin-1. Moreover, abundant microRNAs within HSerCs-EVs (miR-638, miR-149-3p, miR-1246, etc.) had a possible impact on male reproductive disorders such as asthenozoospermia and oligozoospermia. Conclusions: Our study has shown that HSerCs-EVs contain diverse components such as proteins and microRNAs. Further research is required to evaluate HSerCs-EVs in spermatogenesis, which are underutilized but highly potent resources with particular promise for male infertility. [ABSTRACT FROM AUTHOR]

The superconductor was first discovered in liquid metal Hg. Since then, the researches about superconductors have mainly focused on solid materials, instead of the liquid metal alloys. Recently, the gallium–indium–tin (Ga-In-Sn) liquid alloy was found to exhibit superconducting properties at low temperatures. In this work, the superconducting properties of the Ga-In-Sn liquid alloy (Ga:In:Sn = 62:25:13 by weight) and the Zn-doped samples have been studied. The results indicate that the Ga-In-Sn liquid alloy has the superconducting critical temperature (TC) of 6.28 K. With the addition of Zn, the TC is reduced to 6.06 K. Besides, at temperature higher than TC, a change from superconductivity to normal state appears, and with the addition of Zn element into the alloy, the magnetic susceptibility is improved. Therefore, based on the research of liquid metal's superconductivity in this work, more physical properties and applied researches on liquid metal can be proposed in future, and more novel applications can be developed. [ABSTRACT FROM AUTHOR]

Axial-flow pumps are widely employed in urban flood control and drainage pumping stations. The inlet vortex is one factor that seriously threaten the safe, stable and efficient operation of axial-flow pump units. In this paper, the vortex recognition performances of two vortex identification methods, the Q — criterion and Liutex methods, are compared based on an axial-flow pump, and the interactions between the impeller and vortex are explored. A flat plate vortex generator is installed in front of the impeller to continuously induce a stable vortex. The numerical simulation results show that the Liutex method can not only simultaneously identify strong and weak vortices but also reduce the influence of shear force at the sidewall. The vortex and the impeller influence each other. Under the influence of rotating blades, the vortex changes from a low frequency to the blade frequency, and the vortex significantly changes the tangential velocity inside the impeller. The accuracy of the numerical simulation results is verified by experiments on the external and internal characteristics. [ABSTRACT FROM AUTHOR]

The main purpose of this article is to study the calculating problem of the sixth power mean of the two-term exponential sums, and give an interesting calculating formula for it. At the same time, the paper also provides a new and effective method for the study of the high order power mean of the exponential sums. [ABSTRACT FROM AUTHOR]

Vertical rolling is an important technique used to control the width of continuous casting slabs in the hot-rolling field. Accurate prediction of vertical rolling force is a core point maintaining rolling-mill equipment. Owing to the limitation of the algorithm in use, the prediction accuracy of most vertical rolling force models based on the energy method can only reach more than 10%. Therefore, it is challenging to optimize the rolling-force model to improve prediction accuracy. An innovative approach for optimizing the calculation of vertical rolling force with a unified yield criterion is presented in this paper. First, the maximal width of a dog-bone region is determined by the slip-line method, and the dog-bone shape is described using a sine-function model. Second, the velocity and corresponding strain-rate fields satisfying kinematically admissible conditions are proposed to calculate the total power of the vertical rolling process. Finally, the analytical solution of the rolling force and the dog-bone-shape model is obtained by repeatedly optimizing the weighted coefficient b of intermediate principal shear stress on the yield criterion. Moreover, the effectiveness of the proposed mechanical model is verified by measured data in the strip hot-rolling field and other models' results. Results show that the prediction accuracy of the vertical rolling force model can be improved by optimizing the value of b. Then, the impacts of reduction rate, initial thickness, and friction factor on dog-bone shape size and vertical rolling force are discussed. [ABSTRACT FROM AUTHOR]

In order to avoid the destruction of underground aquifers in the eco-environment frangible area caused by the exploitation of coal resources, a new coal mining method with near-zero impact on aquifers (MNIA) was proposed according to the advantages of strip mining and backfill mining methods to effectively control overburden, which is coordinated with the eco-environment. First, the ecological fragile status of the high-intensity mining area is studied. This is followed by the basic principle, technical steps, and its characteristics and advantages of MNIA. Combined with specific mining conditions, theoretical analysis and physical simulation are adopted. Then, the determination principle of strip mining parameters, filling width along the strip coal pillar, width of the narrow pillar in the recovery strip residual pillar and filling rate are given. The MNIA is more effective in thin- and medium-thick coal seams. Based on the long-term stability evaluation method of the strip pillar, it is determined that the narrow coal pillar and backfill body have long-term stability. In addition, the development and utilization of the underground space is proposed, which provides a new solution for the in situ protection of aquifers, effective utilization of underground space, and coordinated development of ecological environment and coal resource exploitation in the eco-environment frangible area. [ABSTRACT FROM AUTHOR]

An experimental study on the traveling crossflow instability over a 60 ∘ swept flat plate was conducted. The Mach number is 6, the angle of attack of the model is 5 ∘ . The traveling crossflow waves and the secondary instability of the traveling crossflow waves were visualized by nano-tracer-based planar laser scattering (NPLS) technique. In the spanwise NPLS images, the traveling crossflow waves appeared as regular strikes, and the secondary instability appeared as small eddies attached to strikes. The wavelet transform was used to study the wavelength contents of the traveling crossflow waves. The most amplified wavelength is stable before the secondary instability happening, which is around 12 mm at R e ∞ = 3.45 × 10 6 m - 1 . Besides, the Reynolds number effects on the boundary layer transition and traveling crossflow instability were discussed. [ABSTRACT FROM AUTHOR]

In recommendation systems, it is of vital importance to comprehensively consider various aspects of information to make accurate recommendations for users. When the low-order feature interactions between items are insufficient, it is necessary to mine information to learn higher-order feature interactions. In addition, to distinguish the different importance levels of feature interactions, larger weights should be assigned to features with larger contributions to predictions, and smaller weights to those with smaller contributions. Therefore, this paper proposes a neural attention model for recommendation (NAM), which deepens factorization machines (FMs) by adding an attention mechanism and fully connected layers. Through the attention mechanism, NAM can learn the different importance levels of low-order feature interactions. By adding fully connected layers on top of the attention component, NAM can model high-order feature interactions in a nonlinear way. Experiments on two real-world datasets demonstrate that NAM has excellent performance and is superior to FM and other state-of-the-art models. The results demonstrate the effectiveness of the proposed model and the potential of using neural networks for prediction under sparse data. [ABSTRACT FROM AUTHOR]

Chalcogen elements, such as sulfur (S), selenium (Se), tellurium (Te) and the interchalcogen compounds, have been studied extensively as cathode materials for the next-generation rechargeable lithium/sodium (Li/Na) batteries. The high energy output of the Li/Na-chalcogen battery originates from the two-electron conversion reaction between chalcogen cathode and alkali metal anode, through which both electrodes are able to deliver high theoretical capacities. The reaction also leads to parasitic reactions that deteriorate the chemical environment in the battery, and different cathode-anode combinations show their own features. In this article, we intend to discuss the fundamental conversion electrochemistry between chalcogen elements and alkali metals and its potential influence, either positive or negative, on the performance of batteries. The strategies to improve the conversion electrochemistry of chalcogen cathode are also reviewed to offer insights into the reasonable design of rechargeable Li/Na-chalcogen batteries. [ABSTRACT FROM AUTHOR]

Flash processing (FP) has attracted considerable attention due to its high efficiency, economic advantages, and the extraordinary opportunity if offers to improve the mechanical properties of steel. In this study, we investigated the influences of FP on the recrystallization (REX) behavior and mechanical performance of cold-rolled IF steel. Using a thermomechanical simulator, we performed both single-stage FPs, at heating rates of 200°C/s and 500°C/s, and two-stage FP, with an initial preheating to 400°C at a rate of 5°C/s and then to peak temperatures at a rate of 200°C/s. In comparison to continuous annealing (CA), single-stage FP can effectively refine the recrystallized grain sizes and produce a similar or even sharper γ (ND (normal direction)//{111}) texture component. In particular, the heating rate of 500°C/s led to an increase in the yield strength of about 23.2% and a similar ductility. In contrast, the two-stage FP resulted in a higher REX temperature as well as a certain grain refinement due to the stored strain energy, i.e., the driving force of REX, which was largely consumed during preheating. Furthermore, both stronger {110}<110> and weaker γ texture components appeared in the two-stage FP and were believed to be responsible for the early necking and deterioration in ductility. [ABSTRACT FROM AUTHOR]

Despite progress in small scale electrocatalytic production of hydrogen peroxide (H2O2) using a rotating ring-disk electrode, further work is needed to develop a non-toxic, selective, and stable O2-to-H2O2 electrocatalyst for realizing continuous on-site production of neutral hydrogen peroxide. We report ultrasmall and monodisperse colloidal PtP2 nanocrystals that achieve H2O2 production at near zero-overpotential with near unity H2O2 selectivity at 0.27 V vs. RHE. Density functional theory calculations indicate that P promotes hydrogenation of OOH* to H2O2 by weakening the Pt-OOH* bond and suppressing the dissociative OOH* to O* pathway. Atomic layer deposition of Al2O3 prevents NC aggregation and enables application in a polymer electrolyte membrane fuel cell (PEMFC) with a maximum r(H2O2) of 2.26 mmol h−1 cm−2 and a current efficiency of 78.8% even at a high current density of 150 mA cm−2. Catalyst stability enables an accumulated neutral H2O2 concentration in 600 mL of 3.0 wt% (pH = 6.6). The synthesis of high concentration H2O2 from water and oxygen at moderate conditions could provide an on-site H2O2 source for medical and water purification applications. Here, authors show Al2O3-stabilized PtP2 nanocrystals to enable selective, stable and efficient neutral pH H2O2 production. [ABSTRACT FROM AUTHOR]

As an important engineering material, aluminum alloy profile is widely used in each department of national economy. With polyurethane mandrel in the hollow of the profiles, equal channel angular pressing (ECAP) can be used to refine mechanical properties of these hollow materials with good shape control effects. However, based on existing researches, the hollow profiles are only limited to circular ones. In this paper, a mechanical analysis of a square tube in ECAP with polyurethane mandrel is provided. Through the slab method in different deformation planes, the mechanical mechanism of shape control effects is found. The thicknesses can be maintained as its initial ones after ECAP. Both simulations and experiments are used to verify the calculated results by the analysis. After calculating, most errors between the final and initial thicknesses in both simulations and experiments are less than 10%. [ABSTRACT FROM AUTHOR]

Using the definition of a black hole's volume introduced by Christodoulou and Rovelli, we calculate the interior volume of a (2 + 1)-dimensional charged Banados Teitelboim Zanelli (BTZ) black hole, and find that the volume increases linearly with time. Afterwards, the entropy of a massless scalar field inside the black hole is calculated and the result indicates that the entropy will be also increasing with time infinitely. Moreover, thinking about Hawking radiation, the ratio of variation of the scalar field's entropy to the variation of Bekenstein–Hawking entropy is approximately a linear function of m, which is quite different from a RN black hole while m is relatively large. In the end, we extend the calculation above to a massive BTZ black hole and find that the relationship with different M ~ between two kinds of entropy is similar to the previous result. But the difference is that the relationship function F (m , q , M ~) will tend to be a constant when the mass parameter M ~ becomes big enough. [ABSTRACT FROM AUTHOR]

The main purpose of this paper is using the analytic method and the properties of the character sums to study the computational problem of one kind hybrid power mean involving the character sums of polynomials and the two-term exponential sums, and give several interesting identities and asymptotic formulae for them. [ABSTRACT FROM AUTHOR]

Tuberculous empyema (TE) is associated with high mortality and morbidity. In the retrospective cohort study, we aimed to find risk factors for TE among pleural tuberculosis (TB) patients. Between July 2011 and September 2015, all culture-confirmed pleural TB patients (474 cases) were enrolled in our study. Empyema was defined as grossly purulent pleural fluid. Demographic and epidemiological data were collected for further analysis. Multivariate logistic regression analysis was used to evaluate risk factors of TE in pleural TB, age–adjusted odds ratio (OR) and 95% confidence interval (CI) were calculated to show the risk. The mean age was 35.7 ± 18.1 years old, males comprised 79.1% of the participants (375 cases). Forty-seven patients (9.9%) were multidrug-resistant TB (MDR-TB), 29 (6.1%) had retreatment TB, 26 (5.5%) had diabetes mellitus. The percentage of empyema patients was 8.9% (42 cases). Multivariate analysis revealed that male (adjusted OR = 4.431, 95% CI: 1.411, 13.919), pleural adenosine deaminase (ADA, >88 U/L) (adjusted OR = 3.367, 95% CI: 1.533, 7.395) and white blood cell (WBC, >9.52 109/L) (adjusted OR = 5.763, 95% CI: 2.473, 13.431) were significant risk factors for empyema in pleural TB, while pulmonary TB (adjusted OR = 0.155, 95% CI: 0.072, 0.336) was the protective factor for the patients. TE remains a serious threat to public health in China. Male sex is a significant risk factor for TE while the presence of pulmonary TB is protective, and high levels of pleural ADA and WBC count could aid in early diagnosis of TE. This finding would help towards reducing the mortality and morbidity associated with TE. [ABSTRACT FROM AUTHOR]

Production of syngas with tunable CO/H2 ratio from renewable resources is an ideal way to provide a carbon-neutral feedstock for liquid fuel production. Ag is a benchmark electrocatalysts for CO2-to-CO conversion but high overpotential limits the efficiency. We synthesize AgP2 nanocrystals (NCs) with a greater than 3-fold reduction in overpotential for electrochemical CO2-to-CO reduction compared to Ag and greatly enhanced stability. Density functional theory calculations reveal a significant energy barrier decrease in the formate intermediate formation step. In situ X-ray absorption spectroscopy (XAS) shows that a maximum Faradaic efficiency is achieved at an average silver valence state of +1.08 in AgP2 NCs. A photocathode consisting of a n+p-Si wafer coated with ultrathin Al2O3 and AgP2 NCs achieves an onset potential of 0.2 V vs. RHE for CO production and a partial photocurrent density for CO at −0.11 V vs. RHE (j−0.11, CO) of −3.2 mA cm−2. Conversion of CO2 into value-added chemicals by use of renewable energy is promising to achieve a carbon-neutral energy cycle. Here, the authors show that AgP2 is a stable, selective and efficient syngas catalyst for solar-to-fuel conversion with a 3-fold lower overpotential compared to the benchmark Ag catalyst. [ABSTRACT FROM AUTHOR]

Highly conductive and flexible graphene-based microtubes (μ-GTs) have many potential applications in catalyst supports and wearable electronics. However, there is a lack of effective method to fabricate the high-performance μ-GTs, especially the multi-channel ones. In this work, the electrostatic spray deposition technique was introduced to fabricate the graphene oxide-coated polyester thread from cost-efficient graphene oxide suspensions. After the polyester thread template was removed along with the reduction of graphene oxide by thermal annealing, the multi-channel μ-GT was prepared successfully. Due to the multiple structure of the cross section and the vertically aligned reduced graphene oxide sheets of the tube wall, the multi-channel μ-GT exhibits many excellent properties, such as highly conductive, good flexibility, and functionalization. For example, the electrical conductivity of the multi-channel μ-GT thermally reduced at 1200 °C is about 1.99 × 104 S m−1 at room temperature and can light a LED as a conductive wire. And the electrical conductivity is nearly invariable in either the straight or bent state though a cyclic bending test up to 800 times. In addition, the TiO2/multi-channel μ-GT composite shows strong photocurrent response in which the multi-channel μ-GT provides a super platform due to the high specific surface area. The high-performance μ-GTs obtained by the simple method opens the immense potentials for application in wearable devices. [ABSTRACT FROM AUTHOR]

This study aimed to determine the effect of excessive fluoride (F) on the morphological characteristics of the small intestine and the contents of serum cytokines in rats. A total of 48 3-week-old healthy female Sprague-Dawley rats were randomly divided into four groups (n = 12). The control group was given deionized distilled water, while the F treatment groups were treated with water containing 25, 50, and 100 mg F−/L. After 70 days of treatment, the duodenum, the jejunum, and the ileum were collected to measure the developmental parameters and the distribution of intestinal glycoproteins, goblet cells, and mast cells through Pannoramic Viewer, Periodic Acid-Schiff (PAS) staining, Alcian blue and periodic acid-Schiff (AB-PAS) staining, and toluidine blue staining, respectively. The contents of cytokines, namely, interleukin (IL)-1β, IL-2, IL-6, and tumor necrosis factor (TNF)-α, in serum were detected via enzyme-linked immunosorbent assay (ELISA). Results showed that the villus height, crypt depth, villus height to crypt depth ratio, goblet cells, glycoproteins, and mast cells of the small intestine significantly decreased (P < 0.05 or P < 0.01) in the F treatment group. The contents of IL-1β, IL-2, IL-6, and TNF-α were significantly lower in the F treatment group than in the control group (P < 0.05 or P < 0.01). In summary, excessive F intake impaired intestinal development and immune function by decreasing the developmental parameters and the distribution of immune cells, glycoproteins, and cytokines. [ABSTRACT FROM AUTHOR]

A series of pyrazolylimine ligated Co(II) and Fe(II) complexes with general formula of (PhC=N(C6H3(R1)2-2,6)(C3HN2 (R2)2-3,5)MtCl2 (R1 = Me, R2 = H, Mt = Co (1a), Fe (2a); R1 = Me, R2 = Me, Mt = Co (1b), Fe (2b); R1 = iPr, R2 = H, Mt = Co (1c), Fe (2c); R1 = iPr, R2 = Me, Mt = Co (1d), Fe (2d); R1 = iPr, R2 = Ph, Mt = Co (1e), Fe (2e)) were synthesized and thoroughly characterized. Determined by single crystal X-ray diffraction, complexes 1b and 2b revealed dimeric structures, in which distorted trigonal bipyramid geometries were adopted for each metal centers. In the presence of ethylaluminum sesquichloride (EASC), all the cobalt complexes displayed high activities in 1,3-butadiene polymerization, affording polybutadienes with predominant cis-1,4 contents (up to 97.0%). Influences of ligand structure and polymerization parameters on catalytic performance were investigated systematically. For pyrazolylimine iron(II) dichloride complexes, the catalytic activities and microstructures of the resultant polybutadienes were highly dependent on ligand structures and polymerization conditions. For complex 2a, changing cocatalyst from trialkyl aluminums to methyl aluminoxane (MAO) led to an shift of selectivity from high cis-1,4- to trans-1,4-/1,2- manner. Being activated by MAO, complexes 2a and 2b gave trans-1,4-/1,2- binary polybutadienes, while complexes 2c, 2d, and 2e afforded cis-1,4- enriched polymers. [ABSTRACT FROM AUTHOR]

To study the impact of leachate recirculation frequency on the transformation of carbon and nitrogen pollutants in a semi-aerobic bioreactor landfill (SABL), three laboratory-scale SABLs were investigated, each using a different leachate recirculation frequency (daily, once each 3 days, and once each 5 days). Results showed that degradation of total nitrogen (TN), ammonium nitrogen (NH4+-N), chemical oxygen demand (COD), and total organic carbon (TOC) could be described using a quadratic polynomial-compound index model. Degradation rates of TN, NH4+-N, COD, and TOC slightly increased from 0.01795, 0.01814, 0.01451, and 0.01166 day−1 to 0.02054, 0.01903, 0.01488, and 0.01203 day−1, respectively, when the recirculation frequency increased from once per 5 days to once per 3 days. When recirculation frequency was increased to daily, degradation rates of TN, NH4+-N, COD, and TOC significantly increased to 0.03698, 0.02718, 0.02479, and 0.02872 day−1, respectively. Moreover, when recirculation frequency increased from once per 5 days to once per 3 days, the gasification rate of nitrogenous and carbonaceous pollutants was enhanced between 20.38 and 8.17%, respectively. When the leachate recirculation rate further increased to daily, only a small amount of carbonaceous and nitrogenous pollutants was transformed to the liquid phase. Thus, increasing the leachate recirculation frequency in an SABL benefits the removal of carbonaceous and nitrogenous pollutants from the reactor. In addition, the greater is the recirculation frequency, the lower is the residual carbon and nitrogen in the solid phase, and the higher is the gasification rate. A proper recirculation frequency promotes the stabilization of landfill leachate. This study provides a theoretical reference and experimental evidence for accelerating the stabilization of MSW and contributes to the macro-control of landfills. [ABSTRACT FROM AUTHOR]

The main purpose of this paper is using the analytic methods, the solutions of the congruence equation mod p and the properties of Gauss sums to study the computational problem of one kind fourth power mean of the general 3-dimensional Kloostermann sums mod p, and give a sharp asymptotic formula for it. [ABSTRACT FROM AUTHOR]

Recent studies have shown that Zinc (Zn) exhibits promising applications for biodegradable medical implants due to the good combination of biocompatibility, biodegradation rate, and mechanical properties. Only a few recent reports can be found on additive manufacturing of Zn parts. Either the obtained density is too low or the process window is quite narrow due to excessive evaporation. This paper aims to clarify the effect of process parameters on densification during the Laser Powder Bed Fusion (LPBF) processing of pure Zn powder and to obtain high relative density in a reasonable process window. Porosity results either from a lack of fusion due to insufficient laser energy or from gas entrapment due to excessive evaporation. The side faces of cubes are attached by numerous partially melted powder particles, which deteriorates the surface quality. The arithmetical mean height (Sa) on side surfaces can be reduced after sand blasting from 10.12 μm to 4.83 μm for as-melted status. Lattice structures are obtained stably with a strut diameter of about 500 μm. Cylinders were manufactured and machined later into the shape of tensile test specimens. The average values of elastic modulus, yield strength, ultimate strength, and elongation were measured as 35.91 GPa, 101.67 MPa, 113.33 MPa, and 10.8% respectively for LPBF manufactured pure Zn parts with relative density over 99.90%. [ABSTRACT FROM AUTHOR]

Shale gas flowback fluid (SGF) is generated during shale gas extraction and typically contains a variety of toxic and refractory organic compounds. In this work, a microwave-activated persulfate process (MW-PS process) was developed to pretreat SGF. The major factors influencing the treatment efficiency of the MW-PS process (PS dose, initial pH, MW power, and reaction time) were optimized, and the synergetic effect (SE), degradation of recalcitrant matter, and energy consumption were systematically investigated. Results showed that the SE of the process reached a high index (i.e., 9.85), suggesting a significant synergetic effect of MW and PS. In addition, under the optimal MW-PS condition (PS dose of 2.5 g/L, MW power of 900 W, and initial pH of 2), chemical oxygen demand removal reached 66.40% in a short reaction time of 10 min. Other analyses demonstrated that benzene series compounds, organic acids, lipid substances, alkanes, antioxidants, and fluorescent dissolved organic matter in SGF were decomposed to smaller-molecule organic matter, suggesting that refractory and toxic organic matter was removed by the MW-PS treatment process. Overall, the results of this study showed that MW-PS technology is an effective and promising method to treat SGF once the operation parameters are optimized. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the effect of fluoride (F) on spermatogenesis in male rats. F− at 50 and 100 mg/L was administered for 70 days, after which the testicular and epididymis tissues were collected to observe the histopathological structure under a light microscope. The ultrastructure of the testis and sperm was also examined via transmission electron microscopy. The apoptosis of spermatogenic cells was measured through terminal deoxynucleotidyl transferase dUTP nick end labeling staining. The expression of proliferation factors, namely, proliferating cell nuclear antigen (PCNA) and Ki-67, in the testicular and epididymis tissues, were assayed through immunohistochemistry. F− at 50 and 100 mg/L significantly damaged the structure of the testis and epididymis, and the testis and sperm ultrastructure exhibited various changes, including mitochondrial swelling and vacuolization, and apsilated and raised sperm membrane. F treatment significantly increased spermatogenic cell apoptosis in the testis. PCNA (P < 0.01) and Ki-67 (P < 0.01) also presented positive expression in the testis. By comparison, no significant changes occurred in the epididymis. In summary, excessive F intake results in spermatogenesis dysfunction by damaging the testicular structure and inducing spermatogenic cell apoptosis in male rats. The positive expression level of PCNA and Ki-67 was a good response to spermatogenesis dysfunction. [ABSTRACT FROM AUTHOR]

A reasonable allocation of load distribution is expected when the full capacity of rolling equipment is exerted, and energy conservation and strip quality requirements are satisfied. In this work, the minimum value of the mill consumptive power summation and the optimum of the mill shape are used as the target function. Based on equipment parameters of a national hot strip rolling mill, a load distribution optimization method (subjected to certain constraints) was applied and a Max-Min ant-colony algorithm was subsequently used to optimize the load distribution of the mill. The optimization value was determined from the optimal path chosen by ants, and the optimum load distribution was obtained after a series of iterations. The compression ratio from upstream stands to downstream stands decreased gradually after optimization by this method, and the proportional crowns varied less than those associated with the traditional energy method. In fact, the amplitude of fluctuation was reduced by nearly 50%, which is favorable for strip shape controlling, and the total dissipative power was lower than that of the energy consumption method. Moreover, the overall power can be reduced by 4.19%, and an optimal rolling load distribution of the hot strip rolling process can be obtained. [ABSTRACT FROM AUTHOR]

This study was designed to investigate the mechanisms of excessive fluoride-induced apoptosis via mitochondria-mediated pathway in skeletal muscle cells (C2C12 cells). C2C12 cells were cultured with the fluoride concentrations (0, 1, and 2.5 mmol/L) for 48 h. The morphology and ultrastructural changes of C2C12 cells were observed using a light microscope and transmission electron microscope (TEM). The protein expression levels of apoptosis factors, including Bax, Bcl-2, cytochrome c (Cyt c), caspase-3, and caspase-9, were measured using real-time polymerase chain reaction (real-time PCR) and immunocytofluorescence. The morphology and ultrastructure of C2C12 cells were seriously damaged by fluoride at 1 and 2.5 mmol/L doses, including swollen mitochondria, vacuolization, ridge breakage, and disappearance of the nuclear membrane. Simultaneously, compared with the control group, the expression levels of Bax, Bcl-2, Cyt c, caspase-3, and caspase-9 were up-regulated after fluoride treatment. Excessive fluoride damages the ultrastructure in mitochondria, leading to the release of Cyt c from the mitochondria to cytoplasm in C2C12 cells; thereby, activated caspases cascade apoptosis process through a mitochondria-mediated pathway. [ABSTRACT FROM AUTHOR]