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With the highly nonlinear relationship between various seismic feature indicators and earthquakes, the researchers can hardly construct an earthquake model. Meanwhile, the lack of samples for destructive earthquakes also leads to inaccurate medium-to-short-term earthquake magnitude predictions. Therefore, this study proposes a novel model for earthquake prediction, named variant detector bagging algorithm (V-detector-bagging). First, we adopt the geological distribution of earthquakes and faults as a criterion to select the appropriate history catalog data area, and the seismic indicators are calculated through the Gutenberg–Richter laws and Panakkat indicators. Then, we propose the V-detector-bagging algorithm, which combines the V-detector algorithm with the bagging method. The proposed algorithm converts the self-tolerance process into a cycle process, during this process, different selves guide samples to spread widely, generate various detectors covering more wide nonself areas, fill holes that are not covered by detectors in nonself areas, and reduce the false negative rate. Thus, the V-detector-bagging algorithm improves the detection performance of the V-detector. Finally, through experimental validation analysis, the proposed algorithm ranked first in the detection rate on Sichuan and Xinjiang catalog data compared to the popular machine learning methods used in predicting earthquakes and the original V-detector algorithm, with Xinjiang yielding the best results. [ABSTRACT FROM AUTHOR]

Background: Although DHFR gene amplification has long been known as a major mechanism for methotrexate (MTX) resistance in cancer, the early changes and detailed development of the resistance are not yet fully understood. Methods: We performed genomic, transcriptional and proteomic analyses of human colon cancer cells with sequentially increasing levels of MTX-resistance. Results: The genomic amplification evolved in three phases (pre-amplification, homogenously staining region (HSR) and extrachromosomal DNA (ecDNA)). We confirm that genomic amplification and increased expression of DHFR, with formation of HSRs and especially ecDNAs, is the major driver of resistance. However, DHFR did not play a detectable role in the early phase. In the late phase (ecDNA), increase in FAM151B protein level may also have an important role by decreasing sensitivity to MTX. In addition, although MSH3 and ZFYVE16 may be subject to different posttranscriptional regulations and therefore protein expressions are decreased in ecDNA stages compared to HSR stages, they still play important roles in MTX resistance. Conclusion: The study provides a detailed evolutionary trajectory of MTX-resistance and identifies new targets, especially ecDNAs, which could help to prevent drug resistance. It also presents a proof-of-principal approach which could be applied to other cancer drug resistance studies. [ABSTRACT FROM AUTHOR]

Granite genesis is crucial to understanding the evolution of continental crust, yet many concerns about granite genesis remain not well answered, such as whether I-type granite contains metasedimentary components, what controls granite compositional diversity, and how granitic plutons are constructed. To explore these issues, we conducted a detailed study on the two-mica plagiogranite, tonalite, and biotite plagiogranite units of the Wujinxia composite pluton in the eastern Qilian orogen, NE Tibetan Plateau. These units comprise two-mica plagiogranite, tonalite (with diorite enclave), and biotite plagiogranite. Zircon U–Pb data reveal that three granitic units formed at ~ 487 Ma, ~ 464 Ma, and ~ 430 Ma, respectively. Magmatic and xenocrystic garnet were identified from the tonalite and biotite plagiogranite, respectively. The two-mica plagiogranite, tonalite, and biotite plagiogranite all belong to low-K series rocks (K2O/Na2O = 0.10–0.26), and were derived from deep crustal sources mainly consisting of juvenile mafic rocks, with involvement of minor metasedimentary rocks in the magma sources of the two-mica plagiogranite and tonalite. The diorite enclave within the tonalite was probably derived from an enriched mantle-derived basaltic magma. Mineral compositions, thermobarometric calculations, and whole-rock geochemical data indicate that the low-K intrusive units of the Wujinxia composite pluton resulted from multiple magmatic systems at different depths. The results suggest that I-type granites can contain metasedimentary components by partial melting of a mixed crustal source, and high-Mn content helps the preservation of high-Ca garnet within such rocks. For a composite pluton spanning a large compositional variation, its compositional diversity is jointly controlled by magma source composition, melting condition and thermal evolution of individual magma pulses, and the resulted assembly style during pluton construction. [ABSTRACT FROM AUTHOR]

SiO2-particle reinforced silicon rubber composite (SP-RSRC) is a widely utilized material that offers shock absorption protection to various engineering structures in impact environments. This paper presents a comprehensive investigation of the mechanical behavior of SP-RSRC under various strain rates, employing a combination of experimental, theoretical, and numerical analyses. Firstly, quasi-static and dynamic compression tests were performed on SP-RSRC utilizing a universal testing machine and split Hopkinson pressure bar (SHPB) apparatus. Nonlinear stress-strain relationships of SP-RSRC were obtained for strain rates ranging from 1×10−3 to 3065 s−1. The results indicated that the composite showed evident strain rate sensitivity, along with nonlinearity. Then, a nonlinear visco-hyperelastic constitutive model was developed, consisting of a hyperelastic component utilizing the 3rd-order Ogden energy function and a viscous component employing a rate-dependent relaxation time scheme. The model accurately characterized the dynamic mechanical response of SP-RSRC, effectively mitigating the challenge of calibrating an excessive number of material parameters inherent in conventional viscoelastic models. Furthermore, the simplified rubber material (SRM) model, integrated within the LS-DYNA software, was chosen to depict the mechanical properties of SP-RSRC in numerical simulations. The parameters of the SRM model were further calibrated based on the strain-stress relationships of SP-RSRC, as predicted by the developed nonlinear visco-hyperelastic constitutive model. Finally, an inverse ballistic experiment using a single-stage air gun was conducted for SP-RSRC. Numerical simulations of SHPB experiments and the inverse ballistic experiment were then performed, and the reliability of the calibrated SRM model was verified by comparing the results of experiments and numerical simulations. This study offers a valuable reference for the utilization of SP-RSRC in the realm of impact protection. [ABSTRACT FROM AUTHOR]

This paper proposes a powerful hybrid Eulerian–Lagrangian (HEL) approach for the analysis of cavity expansion problems. The new approach is applied to analysing the non-self-similar expansion process of a hollow cylinder of critical state soils, considering arbitrary saturation states of soils and both drained and undrained conditions. A closed-form solution for the stresses and displacements in the elastic zone is presented, taking the state-dependent soil moduli and outer boundary effect of the soil cylinder into account. Adopting large strain theory in the plastic zone, the non-self-similar cavity expansion process is formulated into a set of partial differential equations in terms of both Eulerian and Lagrangian descriptions, which is solved by a newly proposed algorithm. The HEL approach is compared with the conventional Eulerian and Lagrangian approaches for the cavity expansion analyses. It is found that the new approach can reduce to the Eulerian approach when the self-similar assumption is satisfied and to the Lagrangian approach when stress–total strain relationships are obtained analytically. Finally, the expansion process is proven to be non-self-similar by showing the stress and deformation paths, and the finite thickness of soil cylinders may greatly influence the cavity expansion behaviour, especially with a small thickness ratio. The HEL approach can provide useful tools for validating advanced numerical techniques for both saturated and unsaturated soils and interpreting pressuremeter tests in small-size calibration chambers. [ABSTRACT FROM AUTHOR]

The permeability characteristics of coal seams are closely related to their structure. In this work, based on the fractal theory, a nonlinear seepage model of gas in a double-porous and double-permeable coal body using the increasing fractal construction method is proposed. The model incorporates parameters with specific physical interpretations, eliminating reliance on empirical constants. The internal interaction between the pore and coal matrix is enhanced, and the permeability control by multiple stresses is explored. The validity of the new model is substantiated by gas radial seepage experiments. Moreover, the contribution coefficient of the slip effect to the permeability is defined, and on this basis, the critical pressure point under multi-stress interaction is experimentally investigated. The aim is to ignore the influence of slip effects when this critical point is exceeded and to make direct calculations on the intrinsic permeability. The results show that the higher the overburden pressure and adsorption pressure are, the higher the critical pore pressure and contribution coefficient are. Moreover, the slip effect contributes more to permeability at lower pore pressures, even at lower overburden pressures. Finally, we explore the variations in slip factor and intrinsic permeability for two fractal dimensions and three stresses based on experiments. The relationship between the slip factor and the aperture distribution is particularly noteworthy, as the latter exerts a more pronounced influence on the former. Additionally, the pore surface tortuosity has a greater impact on the intrinsic permeability, while its influence on the slip effect is negligible. [ABSTRACT FROM AUTHOR]

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Chatter has always been a detrimental problem restricting the improvement of surface quality and processing efficiency in machining processes. Chatter detection is an essential approach to prevent these harmful effects, which aims to identify chatter occurrence at the early stage. Energy entropic methods explain chatter from randomness perspective of energy distribution and are often applied to detect chatter in machining processes. However, the energy of the milling system at the chatter frequency increase slowly at the onset of chatter, which lead to that energy entropy is sometimes challenging to identify weak chatter. In this paper, a new method based on combination of wavelet packet energy entropy and energy ratio is proposed to monitor chatter. By detecting the energy ratio of chatter frequency band, it is feasible to set a threshold to represent the different milling states and can accurately detect weak chatter. The proposed approach is assessed by using preliminary numerical simulation and several milling experiments, and the results demonstrate that the proposed method can effectively detect chatter. [ABSTRACT FROM AUTHOR]

Background: Guidelines recommend high-sensitivity cardiac troponin (hs-cTn) for diagnosis of myocardial infarction. Use of hs-cTn is increasing across the U.S., but questions remain regarding clinical and operational impact. Prior studies have had methodologic limitations and yielded conflicting results. Objective: To evaluate the impact of transitioning from conventional cardiac troponin (cTn) to hs-cTn on test and resource utilization, operational efficiency, and patient safety. Design: Retrospective cohort study in two New York City hospitals during the months before and after transition from conventional cTn to hs-cTn at Hospital 1. Hospital 2 served as a control. Participants: Consecutive emergency department (ED) patients with at least one cTn test resulted. Intervention: Multifaceted hs-cTn intervention bundle, including a 0/2-h diagnostic algorithm for non-ST-elevation myocardial infarction, an educational bundle, enhancements to the electronic medical record, and nursing interventions to facilitate timed sample collection. Main Measures: Primary outcomes included serial cTn test utilization, probability of hospital admission, ED length of stay (LOS), and among discharged patients, probability of ED revisit within 72 h resulting in hospital admission. Multivariable regression models adjusted for age, sex, temporal trends, and interhospital differences. Key Results: The intervention was associated with increased use of serial cTn testing (adjusted risk difference: 48 percentage points, 95% CI: 45–50, P < 0.001) and ED LOS (adjusted geometric mean difference: 50 min, 95% CI: 50–51, P < 0.001). There was no significant association between the intervention and probability of admission (adjusted relative risk [aRR]: 0.99, 95% CI: 0.89–1.1, P = 0.81) or probability of ED revisit within 72 h resulting in admission (aRR: 1.1, 95% CI: 0.44–2.9, P = 0.81). Conclusions: Implementation of a hs-cTn intervention bundle was associated with an improvement in serial cTn testing, a neutral effect on probability of hospital admission, and a modest increase in ED LOS. [ABSTRACT FROM AUTHOR]

In this paper, a generalized formulation for vibration characteristics investigation of bi-dimensional functionally graded martial annular plates of variational thicknesses is built up using the dynamic stiffness method. The distributions of material attribute both in the radial direction and the thickness direction are in a power-law variation of the constituents' volume fraction. General solutions of the government equation of an annular plate are solved by a strong-formed algorithm, then the dynamic stiffness formulation is employed to present the vibration study of the bi-dimensional functionally graded annular plate. Various boundary constrains are considered in the modeling process. Results of present formulation are verified by comparison with existing literature and numerical examples. A systematic parametric study is performed to study the influences of boundary constrains, geometric parameters, and functional material distributions on the free vibration characteristic of the annular plate. Results shows that the natural frequency of radial functionally graded annular plate are the largest and the natural frequency of the bi-dimensional functionally graded annular plate are the minimum when the values of the power laws are both 1. When the power-law index is large, the change of frequency with the power-law index is more obvious. [ABSTRACT FROM AUTHOR]

This paper studies the exact controllability of semilinear q ∈ (1 , 2) -order fractional evolution systems with a weighted delay initial condition in abstract spaces. Firstly, with the aid of properties of the strongly continuous cosine family, the expression of mild solutions of the concerned problem is presented. Exact controllability results are achieved under essential conditions on f. An example as an application is also given. [ABSTRACT FROM AUTHOR]

Purpose: Intraoperative frozen section pathology (FS) is widely used to guide surgical strategies while the accuracy is relatively low. Underestimating the pathological condition may result in inadequate surgical margins. This study aims to identify CT imaging features related to upgraded FS and develop a predictive model. Methods: Collected data from 860 patients who underwent lung surgery from January to December 2019. We analyzed the consistency rate of FS and categorized the patients into three groups: Group 1 (n = 360) had both FS and Formalin-fixed Paraffin-embedded section (FP) as non-invasive adenocarcinoma (IAC); Group 2 (n = 128) had FS as non-IAC but FP as IAC; Group 3 (n = 372) had both FS and FP as IAC. Clinical baseline characteristics were compared and propensity score adjustment was used to mitigate the effects of these characteristics. Univariate analyses identified imaging features with inter-group differences. A multivariate analysis was conducted to screen independent risk factors for FS upgrade, after which a logistic regression prediction model was established and a receiver operating characteristic (ROC) curve was plotted. Results: The consistency rate of FS with FP was 84.19%. 26.67% of the patients with non-IAC FS diagnosis were upgraded to IAC. The predictive model's Area Under Curve (AUC) is 0.785. Consolidation tumor ratio (CTR) ≤ 0.5 and smaller nodule diameter are associated with the underestimation of IAC in FS. Conclusion: CT imaging has the capacity to effectively detect patients at risk of upstaging during FS. [ABSTRACT FROM AUTHOR]

In this work, diboron trioxide and calcium fluoride are applied as composite additives to explore a process suitable for processing low-grade, high-vanadium, ultra-high-titanium vanadium–titanium magnetite. The metallized coal-based direct reduction–electromagnetic separation experiment was conducted. Results show that a good metallization ratio, separation, and the recovery of valuable components can be achieved under the following conditions: 8 pct diboron trioxide additive content, 8 pct calcium fluoride additive content, reduction temperature of 1100 °C, and reduction time of 30 min. The metallization ratio is 94 pct, and the recovery ratio of Fe, V, and Ti are 96, 84, and 85 pct, respectively. The X-ray diffraction results show that the phase transition under this condition is relatively simple, mainly metallic iron and different titanium oxides, without much intermediate product formation. Scanning electron microscope–energy-dispersive spectroscopy analysis shows that different conditions make the reduction products present differently in size, number, shape, and element distribution under different conditions, and this difference leads to differences in the separation and recovery effects of valuable components. The larger the metallic iron particle size is, the better the effect of component separation is. Diboron trioxide plays a role by destroying [SiO4] radicals to promote reduction. Fluorine is mainly diffused into silicate slag phase, and part of calcium fluoride still exists at relatively lower temperature of 1100–1150 °C. Overall, the metallization reduction–magnetic separation process with diboron trioxide and calcium fluoride as composite additives has achieved excellent metallization ratio, satisfied separation and recovery of valuable components, and large-scale lowered reaction temperature and time. [ABSTRACT FROM AUTHOR]

Loess-paleosol sequences have been used in Asia to study climate and environmental changes during the Quaternary. The scarcity of age control datasets and proxy indices analysis data for Asian loess has limited our understanding of loess depositional processes and the reconstruction of paleoclimatic changes from loess-paleosol records. In this study, we present a dataset that includes 1785 quartz optically stimulated luminescence ages and 1038 K-feldspar post-infrared infrared stimulated luminescence ages from 128 loess-paleosol sequences located in different regions of Asia. We generate 38 high-resolution age-depth models of loess records based on the provided datasets. We provide data on 12,365 grain size records, 14,964 magnetic susceptibility records, 2204 CaCO3 content records, and 3326 color reflection records. This dataset contains the most detailed and accurate chronologies and proxy index data for loess records in Asia yet published. It provides fundamental data for understanding the spatial-temporal variations in loess depositional processes and climatic changes across the continent during the mid-late Quaternary. [ABSTRACT FROM AUTHOR]

GeTe is a mid-temperature thermoelectric compound that has shown promise for use in thermoelectric modules. In this study, the interfacial reactions between Ni and GeTe are carried out to determine the suitability of Ni as a barrier layer. Furthermore, the Ni-Ge-Te phase equilibria isothermal sections at 500°C and 400°C are not available in the literature. They have been determined to provide fundamental information and for better understanding of the Ni/GeTe interfacial reactions. Ni-Ge-Te alloys were prepared and equilibrated at 500°C and 400°C revealing two ternary compounds, Ni3GeTe2 and Ni5.45GeTe2, and insignificant ternary solubilities in most of the binary compounds. Ni/GeTe couples were prepared by electroplating Ni on the GeTe substrate, and the reaction layer thickness was 71 μm in the Ni/GeTe couple reacted at 500°C for 24 h. The reaction path was Ni/(Ni3Te2 + Ni)/Ni3Ge/(Ni3Ge + Ni5.45GeTe2)/(Ni5.45GeTe2 + Ni5Ge3)/(Ni5Ge3 + Ni3GeTe2)/(NiGe + Ni3GeTe2)/GeTe at 500°C, and was Ni/(Ni5Ge3 + Ni5.45GeTe2)/(Ni5Ge3 + Ni3GeTe2)/(NiGe + Ni3GeTe2)/GeTe at 400°C. Ni was the primary diffusion species in the Ni/GeTe couples at both temperatures. Significant interfacial reactions were observed in the Ni/GeTe couples reacted at 500°C and 400°C, indicating that Ni might not be suitable as a barrier layer. [ABSTRACT FROM AUTHOR]

Studying the seepage process in fracture channels (where coal particles are deposited) is of great significance for improving the performance of both on-site coal seam water injection and dust reduction technology. Through a self-developed simulation experiment of water-borne coal particle migration and accumulation and computer graphics, we investigated the influencing factors of particle accumulation in water injection and their influence law on seepage, discussed the interaction relationship between the fractal structure of coal and the characteristics of accumulated coal particles, and established a new fractal model of fracture permeability based on different particle accumulation states. The results show that the seepage velocity and the particle size jointly affect the migration and accumulation process of water-borne coal particles. When the coal particle size is constant and the seepage velocity increases, then the output of the coal powder increases, the deposition decreases, and the structure fractal dimension D3 of fractures decreases. At the same seepage velocity, with the increase of the coal particle size, the output of coal powder decreases, the deposition increases, and the structure fractal dimension D3 of fractures increases. In addition, the amount of coal powder produced in the intermittent water injection process is smaller than that produced in the continuous water injection process, more easily leading to accumulation. The variation law of the theoretical permeability with porosity remains consistent for different particle accumulation states: with the increase of porosity, the structure fractal dimension D3 of fractures decreases, while the theoretical permeability increases. The above research results can provide a theoretical basis for reducing the seepage damage of coal under the particle blocking effect. [ABSTRACT FROM AUTHOR]

The microblade technique is an important technological innovation in the Late Pleistocene, and its geographical distribution and diffusion, as well as the relationship between technological changes and paleoclimatic variability in the Last Glacial Maximum, has given rise to heated debates. Northern China contains a large number and range of microblade sites, though the lack of a robust chronology for archeological sites is a limiting factor for ongoing research. Here, we report multidisciplinary investigations at Caodiaoniu (CDN19), a new microblade site in the Lvliang Mountains of the northern Chinese Loess Plateau. Radiocarbon and optically stimulated luminescence (OSL) dating indicates that the depositional sequence spans from 31.5 to 15.9 thousand years ago (ka). The microblade technology dates to between 30.5 and 19.2 ka, representing one of the oldest microblade sites in northern China and one of the most complete Marine Isotope Stage (MIS) 2 cultural sequences. Human occupations at Caodiaoniu correspond with cold and dry environmental conditions. The evidence from Caodiaoniu is consistent with observations of wide-ranging cultural and technological exchanges between North China and the eastern Eurasian steppe. [ABSTRACT FROM AUTHOR]

The migration behavior of valuable components has a certain guiding significance for exploring the oxidation consolidation mechanism of pellets. In this paper, the compressive performance, phase composition and microstructure of oxidized pellets were comparatively calculated and analyzed by XRD, OM, SEM–EDS and FactSage 8.0; the evolution and migration behavior of valuable components in ordinary pellets and vanadium–titanium pellets were studied. The results show that the phase composition and valuable components of pellets gradually migrated and changed through oxidation and solid-phase reaction. Among them, iron element migrated from Fe3O4 (Fe2+, Fe3+, a small amount of V3+, Ti4+), Fe2TiO4 (Fe2+, V3+, Ti4+) to Fe2O3 (Fe3+), FeTiO3 (Fe2+, V3+, Ti4+) and some silicates (Fe2+). Titanium and vanadium migrated into FeTiO3 (Fe2+, V3+, Ti4+) and part of Fe2O3 (V3+, Ti4+). With the increase in roasting temperature, the metal elements in the gangue phase were gradually oxidized and stripped to form the metal oxide phase, resulting in the gradual reduction of the gangue phase area. The metal oxide phase was gradually connected into a sheet-like distribution, and the area gradually increased. The consolidation mechanism of vanadium–titanium pellets was the same as that of ordinary pellets, which was mainly solid-phase consolidation, supplemented by liquid-phase bonding. [ABSTRACT FROM AUTHOR]

Sb2Te3 is an important thermoelectric material. Co is a potential diffusion barrier. This study examined the electroplated Co/Sb2Te3 interfacial reactions at 300 °C, 400 °C and 500 °C. To provide fundamental information and for better understanding the reaction paths, the Co-Sb-Te phase equilibria isothermal sections at these three temperatures are proposed. No ternary compound is found. The 400 °C isothermal section contains (Co), (Sb), (Te), β-CoSb, β-Co1−xTe, CoSb3, δ-(Sb2Te), γ-(SbTe), Sb2Te3 and a continuous solid solution γ-Co(Sb,Te)2. At 500 °C, except for Te being molten, the phase relationships are similar to those at 400 °C. At 300 °C, although γ-CoSb2 and γ-CoTe2 have very significant mutual solubilities, they are two separate phases and do not form a continuous solid solution. In the Co/Sb2Te3 couple reacted at 300 °C, only one reaction phase, γ-CoTe2 with Sb solubility, is formed. Similar results are found in the Co/Sb2Te3 couple reacted 400 °C, and the reaction phase is the continuous solid solution γ-Co(Sb,Te)2. Two reaction phases, β-Co1-xTe and γ-Co(Sb,Te)2, are found in the couple reacted at 500 °C. The compositional ratio of Sb/Te in the reaction phase remained at 2/3 indicates that Co is the dominating diffusion species. The reaction phases are formed rapidly by Co penetration into the Sb2Te3 substrate. A peculiar phenomenon was found with the reaction layer that formed on the side of Co that was not in direct contact with the Sb2Te3 substrate which will be further investigated. [ABSTRACT FROM AUTHOR]

The Paleo-Asian Ocean, as the processor of the Altaids, was a long-lived ocean, and its subduction gave rise to substantial continental growth in the Central Asian continent. However, the location of the major oceanic basin and its evolution history are debatable, impeding our better comprehension of the early accretionary tectonics of the Paleo-Asian Ocean and its link to the reconstruction of the Rodinia. Here, we report our newly discovered Neoproterozoic adakitic rock (Xingxingxia gneissic granite) in the Eastern Tianshan of the southern Altaids to address the above issues. The Xingxingxia gneissic granite displays high Sr/Y ratios (47–114) and strongly fractionated rare earth element (REE) patterns with low concentrations of Y (3.00–6.36 ppm) and Yb (0.23–0.62 ppm), indicative of the adakite affinity. The adakitic rock is depleted in Nb, Ta, P and Ti, and possesses low Mg# (37–42), comparatively high K2O/Na2O ratios (0.75–1.08). Zircon U–Pb dating reveal that the adakitic rock was formed at 869 ± 9 Ma, which has relatively depleted Hf isotopic compositions (εHf(t) = + 1.9 to + 4.7). Their geochemical features are consistent with those of an origin from a thickened lower arc crust. Our work suggests that subduction of the Paleo-Asian oceanic slab beneath the Central Tianshan Arc occurred at least in the Neoproterozoic. Therefore, our study provides a solid and key evidence to show that the tectonic position of the major Paleo-Asian Ocean was located in the South Tianshan, where the paleo-ocean evolved into its mature stage following the subduction beneath the Central Tianshan at ca. 870 Ma. This work also shed light on the reconstruction of Rodinia and the interaction of the Paleo-Asian Ocean and the Jiangnan–North Tarim Ocean. [ABSTRACT FROM AUTHOR]

With the outbreak of the COVID-19 pandemic, blended learning became exceptionally widespread, especially in higher education. As a result, many college students became beginners in this learning method. To identify key factors that impact beginners' continuance intention in blended learning, this study surveyed 1845 first-year college students at a university in central China in the falls of 2020 and 2021 who used blended learning for the first time. Structural equation modeling was employed to verify a model that integrates intrinsic motivation and academic self-efficacy in the Expectation-Confirmation Model of Information System Continuance. The results show that performance expectancy, intrinsic motivation, and satisfaction significantly impact beginners' continuance intention in blended learning. Moreover, performance expectancy, intrinsic motivation, and confirmation significantly impact beginners' continuance intention through mediating variable satisfaction. Academic self-efficacy does not directly impact college students' continuance intention but indirectly impacts their continuance intention through intrinsic motivation. Finally, this study provides suggestions for educators to improve beginners' blended learning experience thus promoting their continuance intention in blended learning. [ABSTRACT FROM AUTHOR]

To suppress the extreme swelling of poly(acrylic acid) (PAA) hydrogels, two series of PAA-based hydrogels with additional non-covalent crosslinks were successfully synthesized by incorporating allyloxypolyethyleneglycol (APEG) or polyvinylpyrrolidone (PVP) to form hydrogen bonds. The developed hydrogels were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR). The swelling and methylene blue (MB) adsorption experiments of them were performed. Both series of hydrogels exhibited moderate swelling ratios of 213–235 g g−1 and excellent removal efficiency of MB (> 92%). Based on kinetic assessments, the MB adsorption process could be well-described by the pseudo-second-order kinetic and Langmuir isotherm models, suggesting a monolayer chemisorption mechanism. The maximum theoretical adsorption capacity (qm) of the PAA-based hydrogel with PVP could achieve 2483.2 mg g−1. Regeneration experiments showed that both series of hydrogels could endure adsorption/desorption for at least 5 consecutive cycles with MB removal efficiency of higher than 80%. Therefore, it was believed that this study could provide a facile method to develop hydrogel adsorbents and a promising adsorbent material with high adsorption capacity for the removal of MB from dye-containing wastewater. [ABSTRACT FROM AUTHOR]

Various nanophotonic devices based on semiconductor wires with a diameter of several ten nanometers have been studied. Nevertheless, studying the optoelectronics properties and performance of such devices based on large-diameter wires is interesting and meaningful. Here, we successfully grew the micronsized indium antimonide (InSb) wires, and examined their nonlinear optical properties by Z-scan and I-scan (power-dependent) methods within the wavelength range of 0.8–2.8 µm. Furthermore, we demonstrated InSb microwires (MWs) working as an effective and robust optical switch within 1–2.8 µm wavelength. The findings can open possibilities for research on more large-diameter MWs made from other semiconductor materials for photonic and electronic devices. [ABSTRACT FROM AUTHOR]

Hypersonic boundary layer transition is a hot yet challenging problem restricting the development and breakthrough of hypersonic aerodynamics. In recent years, despite great progress made by wind tunnel experiment, transition mechanism and transition prediction, only partial knowledge has been gained so far. In this paper, firstly, the specific scenarios of hypersonic boundary layer transition control are clarified. Secondly, the experimental research progress and mechanism of passive control and active control methods under different hypersonic transition control demands are summarized, with their advantages and disadvantages being analyzed separately. Plasma actuation is easy to produce controllable broadband aerodynamic actuation, which has potential in the field of boundary layer transition control. Hence, the following part of the paper focuses on plasma flow control. The feasibility of plasma actuation to control the hypersonic boundary layer transition is demonstrated and the research ideas are presented. Finally, hypersonic boundary layer transition control methods are summarized and the direction of future research is prospected. [ABSTRACT FROM AUTHOR]

Sea sand vanadia-titania magnetite is difficult to pelletize, and it is difficult for iron and steel enterprises to use it as a raw material for ironmaking. In this paper, the high-temperature physicochemical characteristics and sintering behavior of sea sand vanadia-titania magnetite were comprehensively studied and systematically evaluated. The high-temperature metallurgical physicochemical characteristics of different iron ore powders and under different experimental conditions were studied by the micro-sintering experimental system. The high-temperature sintering indexes were comprehensively evaluated by the grey correlation analysis, and the influence of sea sand ore on sintering performance was investigated by sintering pot experiment. The research results show that the high-temperature sintering characteristics of sea sand vanadia-titania magnetite were the worst, and the grey correlation degree was the lowest. The high-temperature sintering characteristics of sintered blocks with sea sand ore were affected by changing the basicity and the addition amount of sea sand ore. When the basicity was 0.8 and the addition amount of sea sand ore was 15 wt%, the evaluation index of grey relational analysis was the best. The vertical sintering speed and tumble index were slightly reduced by adding sea sand ore, but the sinter yield was improved and the particle size distribution of sinter was optimized. The experimental results provide a certain data reference for the actual production of sinter with sea sand vanadia-titania magnetite. [ABSTRACT FROM AUTHOR]

Based on the modified embedded atom method (MEAM) potential suggested by Jin et al. (Appl. Phys. A120: 189, 2015), the molecular dynamics (MD) simulations were adopted to investigate the melting transition of the FCC transition metal Ni, and in the MD simulations, the forces acting on atoms were calculated by using the newly derived formulas. We first studied the melting points of Ni samples with low-index surfaces including Ni(100), Ni(110), and Ni(111). Then, we investigated the structural properties on the surface layers with increasing temperature up to the melting points. The simulation results exhibit that with the temperature increasing, the (110) surface firstly disorders, followed by the (100) surface, while the stability of the (111) surface is maintained until near the melting point. The disorder of surface layer atoms diffuses from the surface to the inside of the crystal lattice. With the density of atoms decreasing on the surface, the premelting effect also increases, being most pronounced on Ni(110) which corresponds to the lowest surface density. This conclusion is linked with the behavior found for the BCC transition metal Fe in our previous simulation study. [ABSTRACT FROM AUTHOR]

The seepage range of dynamic water in coal seam water injection technology directly determines the disaster prevention effect. However, in the process of coal formation, primary particles and secondary particles produced by mechanical crushing will fill in the fracture, which will increase the difficulty of water seepage. Therefore, it is of great significance to clarify the morphology and seepage evolution process of particle filling fracture channel for improving the effect of water injection and dust reduction in coal seam. In this study, a simulation experiment system was developed to explore the structural evolution of seepage channel in coal fracture. Then, computer graphics was used to quantitatively characterize the morphological structure changes of fracture channels. Finally, the permeability evolution law of fractures was explored in combination with the cubic law. The results show that the filling particle migration with water has a significant effect on the expansion and development of fracture channel structure and seepage capacity. After water injection migration, the geometry of water migration channel in fracture changed, which changed the void distribution in fracture and the migration path and space of fluid. With the particle migration out of the fracture, the original fracture structure of the coal sample is gradually opened. The seepage channel is expanded, and the gap width and permeability increase with the increase of water injection time and flow rate. With the increase of filling quality, the permeability of filling fracture in small particle size range decreases, and the permeability of filling fracture in large particle size range is opposite. [ABSTRACT FROM AUTHOR]

With the fast expansion of the industrial Internet of Things (IIoT) in recent years, the requirement for high-speed, dependable, low-latency, and full-coverage IIoT has grown more pressing. Because of the complexities of the industrial environment and the distance of the specific plant site, communication quality is severely hampered. To overcome these challenges, the space-air-ground integrated network (SAGIN) is seen as a viable solution for the IIoT. This article examines SAGIN, IIoT, product life cycle management, and how to handle these difficulties using three methodologies. This paper explores SAGIN, IIoT, product life cycle management, and how three approaches can be used to deal with these difficulties. We first introduce the overall architecture of SAGIN and then use illustrations to explain the concept of product cycle data. The final experimental results demonstrate the effectiveness of our proposed method. [ABSTRACT FROM AUTHOR]

The complex fracture structure of coal bodies determines the seepage characteristics of water within them. Such characteristics are key for accurately guiding the coal seam water injection process. In this paper, nuclear magnetic resonance (NMR) and two characterization parameters (i.e., pore size distribution and porosity) were used to explore the change law of fracture structure in coal under different stress conditions. Based on the analytical geometry theory, the newly obtained NMR water injection displacement image was binarized, and the two-dimensional fractal dimension of the fracture structure ( D s ) was obtained by applying the box dimension method. Through a linear fitting of the T2 spectrum data obtained by NMR, the fractal dimension of the fracture structure distribution ( D V ) was obtained and compared with the three-dimensional fractal dimension of a theoretical fracture. Based on the NMR experimental results, we determined the maximum and minimum pore sizes of the coal fractures, the fractal dimension of coal fracture tortuosity ( D T ), and the relationship between the fractal dimension and porosity. Overall, the results showed that the two fractal dimensions can describe the change law of coal fracture structure under different stress conditions; moreover, they can be used to quantitatively characterize the change law of coal fracture structure during coal seam water injection. This demonstrates the applicability of the above two fractal dimensions in real mechanical environments. [ABSTRACT FROM AUTHOR]

The surface energy and its anisotropy for the body-centered cubic (bcc) transition metals Cr, Fe, Mo, Nb, Ta, V, and W were evaluated by using the modified embedded-atom method proposed by Jin et al. (Appl Phys A 120: 189, 2015). The calculation results show that among all the surface energies for each bcc transition metal Es(110) and Es(111) are the lowest and highest, respectively. Our calculation indicates that the order of the three low-index surface energies is Es(110) < Es(100) < Es(111), which is consistent with the experimental result. The surface energy corresponding to the (hkl) plane surface increases almost linearly as the including angle between the surface and the (110) plane increases. The present results provide the theoretical data for significant insight into the surface energy of the bcc transition metals. [ABSTRACT FROM AUTHOR]

Because of the widespread presence of arsenic in various smelting waste slags, it not only hinders the recycling and utilization of waste slag, but also causes serious pollution to the ecological environment. In this study, As2O3, the main form of arsenic in non-ferrous metal smelting slag, was used as the research object, and FeCl3 was used as the chlorination agent. As2O3 was selectively chlorinated to low-boiling-point AsCl3 gas which was easy to be volatilized and removed by chlorination roasting. According to the thermodynamic calculation results, the feasibility of FeCl3 as the chlorination agent for selective chlorination and low-temperature volatilization of dearsenization was analyzed. The TG–DTA diagram was analyzed by thermogravimetric experiment, and the mass change, endothermic and exothermic behaviors of the As2O3–FeCl3 system during the linear heating process were studied. The effects of roasting temperature, roasting time, and molar ratio of reactants on the chlorination–volatilization of the As2O3–FeCl3 system were investigated. The optimal chlorination roasting conditions were determined with a roasting temperature of 290–300 ℃, a roasting time of 50 min, and a reactant FeCl3/As2O3 molar ratio of 4:1. The results of this study provided a novel idea for the removal of arsenic from smelting slag and dust, but the mechanism and process conditions of chlorination still need to be further studied and optimized. [ABSTRACT FROM AUTHOR]

Axially chiral biaryl motifs possessing ortho-heteroatom-substituted functionalities exist widely in the structures of natural products and have served as foundation for constructing prominent chiral organocatalysts, ligands, functional materials, and even bioactive molecules. However, a general and enantioselective synthesis of such chiral structures with high synthetic value is rare. Taking advantage of the BaryPhos-facilitated asymmetric Suzuki-Miyaura cross-coupling, we have established a general, efficient and enantioselective construction of the ortho sulfur- or nitrogen-substituted axially chiral biaryls. The protocol shows excellent compatibility to various functional groups and structural features, delivering chiral biaryl structures with ortho-sulfonyl groups or with ortho-nitro groups at a broad range of molecular diversity and complexity. The immobilization of BaryPhos on polyethylene glycol (PEG) support has enabled homogeneous enantioselective cross-coupling in aqueous media and the palladium catalyst recycling for multiple times. The method has enabled a concise 10-step asymmetric synthesis of isoplagiochin D as well as the construction of chiroptical molecules with circularly polarized luminescence (CPL) properties. Ortho-heteroatom-substituted axially chiral biaryls are valuable structures in synthetic and medicinal chemistry. Here, the authors established an efficient synthesis of these chiral structures via asymmetric cross-coupling. [ABSTRACT FROM AUTHOR]

While the exact mechanism remains unclear, type 2 diabetes mellitus increases the risk of sarcopenia which is characterized by decreased muscle mass, strength, and function. Whole-transcriptome RNA sequencing and informatics were performed on the diabetes-induced sarcopenia model of db/db mice. To determine the specific function of lncRNA Gm20743, the detection of Mito-Sox, reactive oxygen species, Ethynyl-2′-deoxyuridine, and myosin heavy chain was performed in overexpressed and knockdown-Gm20743 C2C12 cells. RNA-seq data and informatics revealed the key lncRNA-mRNA interactions and indicated a potential regulatory role of lncRNAs. We characterized three core candidate lncRNAs Gm20743, Gm35438, 1700047G03Rik, and their potential function. Furthermore, the results suggested lncRNA Gm20743 may be involved in regulating mitochondrial function, oxidative stress, cell proliferation, and myotube differentiation in skeletal muscle cells. These findings significantly improve our understanding of lncRNAs that may mediate muscle mass, strength, and function in diabetes and represent potential therapeutic targets for diabetes-induced sarcopenia. The role of lncRNA Gm20743 in the development of diabetic sarcopenia is explored using a mouse model. [ABSTRACT FROM AUTHOR]

Plant growth environment plays an important role in shaping soil microbial communities. To understand the response of soil rhizosphere microbial communities in Oplopanax elatus Nakai plant to a changed growth conditions from natural habitation to cultivation after transplant. Here, a comparative study of soil chemical properties and microbial community using high-throughput sequencing was conducted under cultivated conditions (CT) and natural conditions (WT), in Changbai Mountain, Northeast of China. The results showed that rhizosphere soil in CT had higher pH and lower content of soil organic matter (SOM) and available nitrogen compared to WT. These changes influenced rhizosphere soil microbial communities, resulting in higher soil bacterial and fungi richness and diversity in CT soil, and increased the relative abundance of bacterial phyla Acidobacteria, Chloroflexi, Gemmatimonadetes, Firmicutes and Patescibacteria, and the fungi phyla Mortierellomycota and Zoopagomycota, while decreased bacterial phyla Actinobacteria, WPS-2, Gemmatimonadetes, and Verrucomicrobia, and the fungi phyla Ascomycota, and Basidiomycota. Redundancy analysis analysis indicated soil pH and SOM were the primarily environmental drivers in shaping the rhizosphere soil microbial community in O. elatus under varied growth conditions. Therefore, more attention on soil nutrition management especially organic fertilizer inputs should be paid in O. elatus cultivation. [ABSTRACT FROM AUTHOR]

Since 2008, the water level of the Three Gorges Reservoir has been periodically fluctuating between 175 and 145 m. The rise and fall of the reservoir water level result in changes in the seepage field in the slopes on both banks of the reservoir. Groundwater is an important factor affecting the stability and reactivation of landslides. Developing a method to accurately determine the location of the groundwater saturation line is crucial to the evaluation and prediction of landslide stability. In this paper, the phreatic line under the condition of steady seepage is used as the initial value for unsteady seepage, and the analytical solution for the phreatic line on the bank’s slope under the action of reservoir water level changes is mainly modified based on two assumptions about the rate of change in the reservoir water level and the slope of the bank. In addition, through a large number of indoor tests, the relationship between the water yield, the permeability coefficient, and the porosity of the landslide in the Three Gorges Reservoir area is studied in detail, and a formula for the water yield of a soil–rock mixture is proposed. Finally, the modified analytical solution is used to determine the phreatic line in the Shiliushubao landslide, and the results are compared with the numerical analysis and monitoring results. The results show that the modified analytical solution is closer to the actual situation of the phreatic line in the reservoir water level fluctuation zone. [ABSTRACT FROM AUTHOR]

In order to solve the shortcomings of existing negative-pressure water-discharge devices (e.g., small bearing pressure, poor dust removal, slag discharge effect, and large pressure loss), we designed and optimized a new type of gas-drainage and dust-removal device for gas-extraction pipelines. Through the FLUENT software, we used the k-ε renormalization group turbulence model and the discrete phase model to carry out numerical simulations, studying the internal flow field, as well as the pressure and the dust particle distribution induced by the proposed gas-drainage and dust-removal device. The results show that the new device is capable of automatic stage draining and self-cleaning through its mechanical structure, and it can effectively reduce the energy consumption of extraction, improve the utilization rate of gas resources, protect the environment, and improve economic benefits, while saving installation space. When the radius of the diversion pipe is equal to the radius of the unconstrained inner cyclone at the bottom of the diversion pipe, the overall pressure loss caused by the diversion pipe is the lowest. After optimizing the new gas-extraction pipe-drainage and dust-removal device under 20 kPa, we found that it can achieve a negative pressure suction loss < 2.5% and a dust-removal efficiency > 90%. Hence, this device can ensure a high dust collection efficiency, while reducing the pressure loss, saving installation space, and reducing the amount of dust attached inside the pipe blockage when compared to existing negative-pressure water-discharge devices. [ABSTRACT FROM AUTHOR]

The decomposition of monazite using calcium oxide is a clean metallurgy technique for the extraction of rare earth elements. The reaction mechanism between CaO and monazite was studied using the diffusion couple technique, while the interfaces under varying annealing temperatures and durations were characterized using X-ray diffraction, electron probe microanalysis, and energy-dispersive X-ray spectroscopy. The interdiffusion coefficients and diffusion activation energies of Ca and Ce in the diffusion layer were calculated, where the corresponding kinetic analysis indicated that the reaction between CePO4 and CaO was controlled by diffusion. The diffusion mechanism was further discussed based on the vacancy mechanism. [ABSTRACT FROM AUTHOR]

This study combined with bioinformatics analysis and investigated the expression pattern of miR-181b-5p, as well as explored its role and mechanism in cholangiocarcinoma (CCA or CHOL). Several bioinformatics databases were used to analyze the expression of miR-181b and the enrichment of miR-181b in biological activities and biological pathways in CCA. The RT-qPCR analysis was used to examine the expression levels of miR-181b-5p. A receiver operation characteristics (ROC) curve analysis and the Kaplan–Meier survival assay were conducted to validate the diagnostic and prognostic implication of miR-181b-5p. Cell experiments were used to explore the possible functional role of miR-181b-5p in CCA progression. The bioinformatics assay was used to predict the target gene of miR-181b-5p and Western blot was used to confirm the related signaling pathway. The bioinformatics analysis results suggest that miR-181b-5p was highly expressed in cholangiocarcinoma and its expression was negatively related to PARK2 expression in CCA tissues. miR-181b-5p expression in the serum and tissues was upregulated and associated with lymph node metastasis and TNM stage. Increased expression of miR-181b-5p had relatively high diagnostic accuracy and showed poor prognosis in CCA patients. In addition, miR-181b-5p overexpression enhanced cell proliferation, migration, and invasion by targeting PARK2. Overexpression of miR-181b-5p activated the PI3K/AKT signaling pathway, while knockdown of miR-181b-5p suppressed the signaling pathway. Increased expression of miR-181b-5p in CCA may be a potential diagnostic or/and prognostic indicator for CCA patients. The present data indicated miR-181b-5p acted as an oncogene in CCA through promoting tumor cell proliferation, migration, and invasion of CCA via the PTEN/PI3K/AKT signaling pathway by targeting PARK2, which might be a promising therapeutic target or biomarker for CCA. [ABSTRACT FROM AUTHOR]

In order to reveal the evolution characteristics of the frost heaving pressure caused by the water–ice phase transition and volume expansion of the fractured rock mass subjected to the periodic freeze-thaw cycles, and the degradation effect of the freeze-thaw cycle on the mechanical properties of the fractured rocks, the long-term frost heaving pressure monitoring and uniaxial compression test were carried out on saturated fractured granite with different crack size. The results show that the evolution curve of frost heaving pressure can be divided into five stages. With the increase of freeze-thaw cycles, the peak frost heaving pressure decreases exponentially. The peak frost heaving pressure increases linearly with the increase of crack length. The influence of size effect on frost heaving pressure decreases with the increase of freeze-thaw cycles. As the number of freeze-thaw cycles increases, the rate of P-wave velocity decreases gradually. The peak stress loss rate of rock with different crack length increases in the form of power function with the increase of freeze-thaw cycles. The peak strain changes in the form of quadratic polynomial function with the increase of freeze-thaw cycles. The research results can provide reference for theoretical calculation and numerical analysis of frost heaving pressure of fractured rock mass in cold regions. [ABSTRACT FROM AUTHOR]

In terms of regional water resources, precipitation is a critical component. The accurate assessment of precipitation is critical for the sensible development and use of regional water resources. The elevation influence on regional infiltration from precipitation at different monitoring locations was evaluated using variations in topography and geomorphology in the Chongli District of Zhangjiakou City, Hebei Province, as a case study area in this study. The findings show that precipitation increases considerably with elevation, with a gradient of 21.3 mm per 100 m. According to this effect, the regional precipitation infiltration was calculated as 6302.20×104 m3, and the comprehensive precipitation infiltration coefficient was 0.056, which demonstrated a substantial impact of the precise elevation effect on the calculation of regional recharge. This finding is helpful for the regional management of water resources. [ABSTRACT FROM AUTHOR]

As a subclass of carbon dots, carbonized polymer dots (CPDs) are attracting more and more attention. But the facile preparation of full-color emitting CPDs has been rarely reported yet. Herein, we present a versatile and facile strategy for the preparation of photoluminescence (PL) CPDs, whose aqueous solutions can emit three primary colors under a single ultraviolet-light excitation. The difference in the PL emission of these CPDs is ascribed to the differences in nitrogen and oxygen contents. It is believed that the facile preparation approach would provide a promising alternative route for preparing full-color emitting CPDs. [ABSTRACT FROM AUTHOR]

Microgravity is a component of the complex environment in space. Due to its adverse effects on the human body, it poses unknown obstacles to the implementation of space missions. In microgravity, the body often loses the point of force and it is difficult to control itself, which leads to various accidental collisions. As the largest organ of the human body, the skin is often damaged by traumatic injury because of its large contact area with the external environment. In this study, we summarized and discussed the latest research on the impact of weightlessness or simulated microgravity on the skin and the process of wound healing to further understand the changes and mechanisms of wound healing. A series of studies have investigated the effects of weightlessness or simulated microgravity on the human skin and the wound healing process. Under microgravity environment, the skin showed certain changes, such as thinning and altered blood supply; microgravity also affected various cellular functions and their associations with the extracellular matrix during wound healing. Various stages of wound healing and sophisticated interactions between the elements involved in wound healing become disordered in a microgravity environment. However, more studies are needed to further understand the impact and mechanisms of microgravity on the trauma repair process to provide theoretical guidance for wound healing. With the support and help of a lot of good researches and trails, accidental trauma will no longer be an obstacle to human exploration of space. [ABSTRACT FROM AUTHOR]