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Nuclear power is a high-quality clean energy source, but nuclear waste is generated during operation. The waste continuously releases heat during disposal, increasing the adjoining rock temperature and affecting the safety of the disposal site. Basalt is widely considered a commonly used rock type in the repository. This study of basalt's mechanical characteristics and damage evolution after thermal damage, with its far-reaching engineering value, was conducted by combining experimental work and theory. Uniaxial compression tests were conducted on basalt exposed to 25 °C, 500 °C, 700 °C, 900 °C, and 1100 °C conditions, and acoustic emission (AE) equipment was utilized to observe the acoustic emission phenomenon during deformation. This study was carried out to examine the mechanical characteristics, the sound emission features, the progression of damage laws, and the stress–strain framework of basalt after exposure to different types of thermal harm. As the temperature rises, the rock's maximum strength declines steadily, the peak strain rises in tandem, the rock sample's ductility is augmented, the failure mode changes from shear to tensile failure, and cracks in the failure area are observed. At room temperature, the acoustic emission signal is more vigorous than in the initial stage of rock sample loading due to thermal damage; however, after the linear elastic stage is entered, its activity is lessened. In cases where the rock approaches collapse, there is a significant surge in acoustic emission activity, leading to the peak frequency of acoustic emission ringing. The cumulative ring count of acoustic emission serves as the basis for the definition of the damage variable. At room temperature, the damage evolution of rock samples can be broken down into four distinct stages. This defined damage variable is more reflective of the entire failure process. After exposure to high temperatures, the initial damage of the rock sample becomes more extensive, and the damage variable tends to be stable with strain evolution. The stress–strain constitutive model of basalt deformation is derived based on the crack axial strain law and acoustic emission parameters. A powerful relationship between theoretical and experimental curves is evident. [ABSTRACT FROM AUTHOR]

Featured Application: A fiducial marker reader system, featuring a novel marker design, has been proposed to guide mobile robots in accomplishing high-precision docking missions within smart factories. The implementation of this technology can provide a cost-effective and readily deployable sensor solution for automated docking in various scenarios. Accurately docking mobile robots to various workstations on the factory floor is a common and essential task. The existing docking methods face three major challenges: intricate deployment procedures, susceptibility to ambient lighting, and incapacity to recognize product information during the docking process. This paper devises a novel approach that combines the features of ArUco and Data Matrix to form a composite marker termed "DataMatrix-ArUco-Hybrid" (DAH). The DAH pattern serves as a fiducial marker capable of concurrently providing both target pose information and product information. Detection of the DAH pattern is conducted by a cost-effective fiducial marker reader system, called "FiMa-Reader", which comprises an embedded processing unit and an infrared camera equipped with a 940 nm fill-light to overcome lighting issues. The FiMa-Reader system effectively detects the DAH pattern under both well-lit and dimly lit conditions. Additionally, the implementation of the FiMa-Reader system leads to significant improvements in positioning accuracy, including an 86.42% improvement on the x-axis, a 44.7% improvement on the y-axis, and an 84.21% improvement in angular orientation when compared to traditional navigation methods. The utilization of FiMa-Reader presents an economically viable system capable of guiding mobile robots' positioning with high precision in various indoor lighting conditions. [ABSTRACT FROM AUTHOR]

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For pattern knots admitting genus-one doubly pointed bordered Heegaard diagrams, we give an immersed-curve approach to compute the knot Floer chain complexes of the corresponding satellite knots. In particular, this approach provides a convenient way to compute the knot concordance invariant τ . For patterns P obtained from two-bridge links b(p, q), we derive a formula for the τ -invariant of P (T 2 , 3) and P (- T 2 , 3) in terms of (p, q). We use this formula to study whether such patterns induce homomorphisms on the knot concordance group, providing a glimpse at a conjecture due to Hedden. [ABSTRACT FROM AUTHOR]

Background: Intermediate vertebral collapse is a newly discovered complication of consecutive two-level anterior cervical discectomy and fusion (ACDF). There have been no analytical studies related to the effects of endplate defects on the biomechanics of the intermediate vertebral bone after ACDF. This study aimed to compare the effects of endplate defects on the intermediate vertebral bone biomechanics in the zero-profile (ZP) and cage-and-plate (CP) methods of consecutive 2-level ACDF and to determine whether collapse of the intermediate vertebra is more likely to occur using ZP. Methods: A three-dimensional finite element (FE) model of the intact cervical spine (C2–T1) was constructed and validated. The intact FE model was then modified to build ACDF models and imitate the situation of endplate injury, establishing two groups of models (ZP, IM-ZP and CP, IM-ZP). We simulated cervical motion, such as flexion, extension, lateral bending and axial rotation, and compared the range of motion (ROM), upper and lower endplate stress, fusion fixation device stress, C5 vertebral body stress, intervertebral disc internal pressure (intradiscal pressure, or IDP) and the ROM of adjacent segments in the models. Results: There was no significant difference between the IM-CP model and the CP model in the ROM of the surgical segment, upper and lower endplate stress, fusion fixation device stress, C5 vertebral body stress, IDP, or ROM of the adjacent segments. Compared with the CP model, the endplate stress of the ZP model is significantly higher in the flexion, extension, lateral bending and axial rotation conditions. Compared with the ZP model, endplate stress, screw stress, C5 vertebral stress and IDP in IM-ZP were significantly increased under flexion, extension, lateral bending and axial rotation conditions. Conclusions: Compared to consecutive 2-level ACDF using CP, collapse of the intermediate vertebra is more likely to occur using ZP due to its mechanical characteristics. Intraoperative endplate defects of the anterior lower margin of the middle vertebra are a risk factor leading to collapse of the middle vertebra after consecutive 2-level ACDF using ZP. [ABSTRACT FROM AUTHOR]

During the Coronavirus disease 2019 pandemic, short-range virus transmission has been observed to have a higher risk of causing infection than long-range virus transmission. However, the roles played by the inhalation and large droplet routes cannot be distinguished in practice. A recent analytical study revealed the predominance of short-range inhalation over the large droplet spray route as causes of respiratory infections. In the current study, short-range exposure was analyzed via computational fluid dynamics (CFD) simulations using a discrete phase model. Detailed facial membranes, including eyes, nostrils, and a mouth, were considered. In CFD simulations, there is no need for a spherical approximation of the human head for estimating deposition nor the "anisokinetic aerosol sampling" approximation for estimating inhalation in the analytical model. We considered two scenarios (with two spheres [Scenario 1] and two human manikins [Scenario 2]), source-target distances of 0.2 to 2 m, and droplet diameters of 3 to 1,500 µm. The overall CFD exposure results agree well with data previously obtained from a simple analytical model. The CFD results confirm the predominance of the short-range inhalation route beyond 0.2 m for expiratory droplets smaller than 50 µm during talking and coughing. A critical droplet size of 87.5 µm was found to differentiate droplet behaviors. The number of droplets deposited on the target head exceeded those exposed to facial membranes, which implies a risk of exposure through the immediate surface route over a short range. [ABSTRACT FROM AUTHOR]

The tailings pond is a dangerous source of man-made debris flow with high potential energy. The oxidative acidification of tailings may cause the instability of the pond and induce serious safety accidents. The influence of oxidation and acidification degree on macro mechanical properties of tailings is discussed from the aspects of mineral composition and microstructure. The results show that as the degree of oxidation and acidification of tailings sand increases, the overall structural performance and load-bearing capacity decrease, and its cohesion (c) and internal friction angle (φ) show a decreasing trend. In fact, the engineering properties of tailings with different oxidation and acidification degrees are dominated by the physicochemical composition and structural characteristics. On the one hand, as the degree of oxidation increases, acidic substance will neutralize with CaCO3 and CaMg(CO3)2, resulting in the loss of cemented substance and the decrease of cementation force between tailing sand particles as well as the gradual destruction of the integrity of tailing sand. On the other hand, the increase of oxidation and acidification degree of tailing sand leads to a gradual reduction of outline (2D) fractal dimension and gray surface (3D) fractal dimension of surface laminated structure as well as the obvious reduction of laminated structure and its roughness of tailings sand. [ABSTRACT FROM AUTHOR]

Rockburst is a common geological disaster in the process of deep rock excavation, and stress gradient is an important factor affecting rockburst. In this paper, the concept of “stress concentration” was proposed. The relevant data of a large number of engineering rockburst cases were statistically analyzed, and a new rockburst criterion of stress–strength ratio considering stress gradient of surrounding rock was established. The research results revealed that the rockburst criterion considering the stress gradient distribution of surrounding rock could effectively overcome the problem of non-uniform division of rockburst criteria in the traditional strength-to-stress ratio. It can fully reflect the influence of tunnel size effect on rockburst. There was a significant correlation between rockburst strength and stress gradient, and different rockburst strengths showed obvious zoning concentration phenomenon on the two-dimensional plane. The established rockburst criterion considering the stress intensity ratio of surrounding rock had strong applicability, and the prediction accuracy could reach more than 90%. The proposed rockburst criterion in this paper has certain theoretical and engineering guiding value for the early warning of underground engineering disasters. [ABSTRACT FROM AUTHOR]

Objective: The injury of the annular ligament can change the stress distribution and affect the stability of the elbow joint, but its biomechanical mechanism is unclear. The present study investigated the biomechanical effects of different flexion angles of the annular ligament on elbow joint stability. Methods: A cartilage and ligament model was constructed using SolidWorks software according to the magnetic resonance imaging results to simulate the annular ligament during normal, loosened, and ruptured conditions at different buckling angles (0°, 30°, 60°, 90°, and 120°). The fixed muscle strengths were 40 N (F1), 20 N (F2), 20 N (F3), 20 N (F4), and 20 N (F5) for the triceps, biceps, and brachial tendons and the base of the medial collateral ligament and lateral collateral ligament. The different elbow three‐dimensional (3D) finite element models were imported into ABAQUS software to calculate and analyze the load, contact area, contact stress, and stress of the medial collateral ligament of the olecranon cartilage. Results: The results showed that the stress value of olecranon cartilage increased under different conditions (normal, loosened, and ruptured annular ligament) with elbow extension, and the maximum stress value of olecranon cartilage was 2.91 ± 0.24 MPa when the annular ligament was ruptured. The maximum contact area of olecranon cartilage was 254 mm2 with normal annular ligament when the elbow joint was flexed to 30°, while the maximum contact area of loosened and ruptured annular ligament was 283 and 312 mm2 at 60° of elbow flexion, and then decreased gradually. The maximum stress of the medial collateral ligament was 6.52 ± 0.23, 11.51 ± 0.78, and 18.74 ± 0.94 MPa under the different conditions, respectively. Conclusion: When the annular ligament ruptures, it should be reconstructed as much as possible to avoid the elevation of stress on the surface of the medial collateral ligament of the elbow and the annular cartilage, which may cause clinical symptoms. [ABSTRACT FROM AUTHOR]

The existence of joints has a significant influence on the failure characteristics of rock mass. In this paper, based on two-dimensional (2D) particle flow code (PFC2D), uniaxial compression tests are conducted on the granite specimens with a single joint at different dip angles to investigate the evolution laws of macroscopic and mesoscopic failure characteristics. The results demonstrate that macro-mechanical characteristics of rock are influenced by the dip angle of the joint. The peak strength, peak deformation, and elastic modulus are positively correlated with the dip angle of the joint, while Poisson's ratio is negatively correlated. With the increase in the dip angle of the joint, mechanical characteristics of rock finally tend to be consistent with those of an intact rock specimen. In addition, when the dip angle of the joint is small, the rock specimens show obvious plastic characteristics before reaching the peak and there are multiple peaks being found on stress–strain curves. As the dip angle of the joint rises, the number of stress fluctuations gradually decreases and the curve near the peak becomes straighter and sharper. Moreover, the rock specimens exhibit more obvious brittle characteristics. The increase in the dip angle of the joint enhances the tendency of azimuth angle of microcracks to develop along the direction of the maximum principal stress. In the meanwhile, the distribution of the azimuth angle is gradually similar to that of microcracks in the intact specimen. With the rise of the joint dip angle, the failure modes of rock specimens change from tensile failure to shear failure to tensile failure, and finally tend to be consistent with the intact rock. [ABSTRACT FROM AUTHOR]

For studying the mechanical properties of sulfur-containing tailings material in the acidification environment, the tailings material was soaked in H2O2 solution with different concentrations to simulate the oxidation and acidification of the tailings with different accumulation history. The change laws and mechanisms of its mechanical properties after oxidation and acidification were discussed, and through the PFC (particle flow code) mesoscopic discrete element analysis method, the connection between mesoscopic particles and its macroscopic properties was established. The experimental results show that the chemical immersion tests on tailings materials with a certain ratio of hydrogen peroxide to concentrated sulfuric acid can well simulate the joint action of oxidation and acidification, so as to simulate the tailings with different accumulation history. Under the action of oxidation and acidification, the physical and mechanical properties of tailings material are mainly affected by the particle size and contact characteristics. The angle of internal friction decreases, influenced by the reduction of particle size, while the change of cohesive force is greatly correlated with both of the two factors. The shear modulus under different porosity and friction coefficients is basically the same, but the increase of porosity or the decrease of mesoscopic particle friction coefficient will greatly weaken its shear capacity, that is, its mesoscopic particle compactness and contact characteristics have an important impact on the macroscopic mechanical properties of tailings. [ABSTRACT FROM AUTHOR]

In this paper, we develop a lower bound for the double slice genus of a knot using Casson-Gordon invariants. As an application, we show that the double slice genus can be arbitrarily larger than twice the slice genus. As an analogue to the double slice genus, we also define the superslice genus of a knot, and give both an upper bound and a lower bound in the topological category. [ABSTRACT FROM AUTHOR]

Fox conjectured the Alexander polynomial of an alternating knot is trapezoidal, i.e. the absolute values of the coefficients first increase, then stabilize and finally decrease in a symmetric way. Recently, Hirasawa and Murasugi further conjectured a relation between the number of the stable coefficients in the Alexander polynomial and the signature invariant. In this paper we prove the Hirasawa–Murasugi conjecture for two-bridge knots. [ABSTRACT FROM AUTHOR]

Close contact was first identified as the primary route of transmission for most respiratory infections in the early 20th century. In this review, we synthesize the existing understanding of the mechanisms of close contact transmission. We focus on two issues: the mechanism of transmission in close contact, namely the transmission of the expired particles between two people, and the physical parameters of close contact that affect the exposure of particles from one individual to another, or how the nature of close contact plays a role in transmission. We propose the existence of three sub‐routes of transmission: short‐range airborne, large droplets, and immediate body‐surface contact. We also distinguish a "body contact," which is defined with an interpersonal distance of zero, from a close contact. We demonstrate herein that the short‐range airborne sub‐route may be most common. The timescales over which data should be collected to assess the transmission risk during close contact events are much shorter than those required for the distant airborne or fomite routes. The current paucity of high‐resolution data over short distances and timescales makes it very difficult to assess the risk of infection in these circumstances. [ABSTRACT FROM AUTHOR]

Purpose: Osteosarcoma (OS) is the most common primary malignant tumor of the bone in young adolescents and children. We explored the underlying mechanism of Aurora-B in promoting OS cell proliferation and metastasis. Patient and Methods: Bioinformatics was employed to predict the substrate of Aurora-B. IHC and Western blot were used to confirm the correlation between Aurora-B and NPM1. ERK/NF-κβ pathway-related proteins were detected by Western blot and immunofluorescence (IF). CCK8, wound healing, transwell, and Tunel assays were used to identify the cell proliferation, migration and apoptosis potential. Spontaneous metastasis xenografts were established to confirm the role of Aurora-B and NPM1. Results: Aurora-B promotes NPM1 phosphorylation on Ser125. The phosphorylation of NPM1Ser125 induced by Aurora-B activates the ERK/NF-κβ signaling. Further study revealed that Aurora-B promotes proliferation, migration and inhibits apoptosis via phosphorylating NPM1 in vitro and in vivo. Conclusion: Aurora-B promotes OS malignancy via phosphorylating NPM1Ser125 and activating ERK/NF-κβ signaling. [ABSTRACT FROM AUTHOR]

To predict B cell epitope of Ewing's sarcoma EWS/FLI-l fusion protein and to analyze its antigenicity and immunogenicity. Comprehensive algorithms were applied to predict the possible B cell epitopes of EWS/FLI-l fusion protein. High-performance liquid chromatography (HPLC) and mass spectrometry (MS) analysis were performed to identify the synthesized epitope peptides, ELISA assays and Western blot to detect the antigenicity, and the immunogenicity of epitope peptides. Three B cell epitopes were screened out, and HPLC and MS analysis confirmed all three synthesized epitope peptides were demandable. ELISA assays verified all three epitope peptides could prime intense antigen-antibody reaction and induce ideal antibody titers after immunization to the New Zealand white rabbit. However, Western blot confirmed that antiserum of one of these epitope peptides could not recognize EWS/FLI-1 protein. Two B cell epitopes, PQDGNKPTETSQPQ and DPDEVARRWGQRKS, derived from EWS/FLI-l protein, are identified to have potential antigenicity and immunogenicity. [ABSTRACT FROM AUTHOR]