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The elastic modulus of rocks is a measure of the ability of rocks to resist elastic deformation. It is related to the size of rocks and can effectively measure the internal physical and mechanical strength of rocks. The development of joint fractures is the main reason for the size effect of rocks. Therefore, exploring the influence of joint roughness on the elastic modulus of rocks of different sizes is of great significance in mining rock mechanics. The article investigates the size effect of joint roughness on elastic modulus of rocks by establishing simulation schemes for 30 working conditions. By analyzing the stress-strain curves of rocks with different roughness and sizes, the deformation and failure patterns of rocks with different sizes were obtained. Research has found that the elastic modulus of rocks is in a power function relationship with joint roughness, while the elastic modulus of rocks is negatively exponentially related to rock size; The characteristic elastic modulus of rocks is in a power function relationship with joint roughness. The above relationships not only reveal the variation of rock elastic modulus with size, but also reveal the influence of joint roughness on elastic modulus, providing important basis for understanding the stability of mining rock engineering.

Abstract Purpose Salvianolic acid B (Sal B) possesses strong anti-inflammatory and antioxidant activity. This study aims to explore the underlying mechanism of Sal B to improve the obesity-related osteoarthritis (OA). Methods C57BL/6 J male mice were fed with a normal control diet (NCD), a high fat diet (HFD), or HFD with Sal B (25 mg/kg), and mouse body weights and osteoarticular inflammatory factor levels were examined. Mouse chondrogenic cell line ATDC5 were transfected with lncRNA KCNQ1 overlapping transcript 1 small hairpin RNA (KCNQ1OT1 shRNA), miR-128-3p mimic or Sirtuin-1 small interfering RNA (SIRT1 siRNA), then stimulated with Palmitic acid (PA) followed by the treatment of Sal B. Then, inflammatory response, apoptosis, and autophagy of ATDC5 cells in different groups were detected. Results Sal B reduced the body weight, decreased the levels of inflammatory markers, and improved cartilage damage in OA mice fed with HFD. KCNQ1OT1 was downregulated in OA mice fed with HFD, and PA-stimulated ATDC5 cells. Sal B protected ATDC5 cells against PA-mediated inflammation, apoptosis, and the inhibition of autophagy, while knockdown of KCNQ1OT1 reversed these results. KCNQ1OT1 was found to be functioned as a ceRNA to bind and downregulate the expression of miR-128-3p that was upregulated in PA-induced cells. Furthermore, SIRT1 was verified as a target of miR-128-3p. MiR-128-3p overexpression reversed the effects of Sal B on inflammatory response, apoptosis, and autophagy in PA-stimulated cells, and knockdown of SIRT1 displayed the similar results. Conclusion Sal B exerted a chondroprotective effect by upregulating KCNQ1OT1, which indicates Sal B can used for a therapeutic agent in obesity-related OA.

The relationship between the rock’s elastic modulus and deformation characteristics, affected by joint spacing and ductility, was not determined. This study investigates the size effect of the elastic modulus of rock with parallel joints using numerical simulation and regression analysis. The results showed an exponential relationship between elastic modulus and spacing of parallel joints and a negative exponential relationship between elastic modulus and rock size. The characteristic size of elastic modulus has a power function relationship with the parallel joints spacing, and the characteristic elastic modulus of rock has a power function relationship with the parallel joints spacing. The general and specific forms of these relationships are provided. Establishing these relationships allows for predicting and calculating the elastic modulus of the mine rock mass and serves as a reference for the deformation analysis of the rock.

The shear strength of a structural plane is a critical parameter in the analysis of engineering rock stability. Significant differences exist due to the various normal stresses in the structural plane. Therefore, evaluating the rock deformation to effectively determine the influence of normal stresses at different scales on the shear strength of structural planes is of great significance. This study discusses the effects of normal stress and structural plane size on shear strength through numerical simulations and regression analysis. The results showed that the shear strength of the structural plane increases linearly with increasing normal stress. The shear strength of the structural plane decreases with increasing size, and the corresponding curve is exponential. The characteristic size and shear strength increase linearly with increasing normal stress. This paper presents the concrete form of these relationships, which can be used to calculate and predict the shear strength, which has significance in guiding engineering.

The bulk modulus reflects the deformation of rock macroscopically and plays a vital role in geological exploration, oilfield development, and drilling. The bulk modulus not only changes under different rock sizes, but also varies with joint roughness. Therefore, it is very important to accurately estimate the bulk modulus of rough jointed rock and evaluate its deformation. In this paper, the influence of joint roughness and rock size on bulk modulus was discussed by regression analysis of 25 sets of simulation models. The research shows that with the increase of rock size, the bulk modulus decreases exponentially, and with the rise of joint roughness, the bulk modulus increases as a power function. With the rise of joint roughness, the characteristic size of bulk modulus increases exponentially, and the characteristic bulk modulus increases as a power function. The paper gives the specific forms of these relations.

The secant modulus of the rock reflects the stiffness of the rock and the ability to resist deformation. There are significant differences in the secant modulus of the rock due to the different numbers of joints in the rock and the change in rock size. Therefore, it is important to obtain effectively the secant modulus of rocks with the number of parallel joints for evaluating rock deformation. In this study, the method of regression analysis is used, and 10 sets of numerical plans are set up to discuss the influence of a number of parallel joints and rock size on the secant modulus. The results show that the secant modulus decreases with the increase in a number of parallel joints, and the curve is a power function. The secant modulus decreases when the rock size increases, and the curve is an exponential function. The characteristic secant modulus and characteristic size decrease with the increase in the number of parallel joints, and their curves are an exponential function. The specific forms of these relationships are given in the article. The establishment of these relationships realizes the prediction and calculation of the rock secant modulus with the number of parallel joints, which provides a guiding significance for the rock deformation analysis.

The number of joints existing in the rock affects the elastic modulus of the rock, and the relationship has not been obtained. In this paper, 10 numerical models are established by numerical simulations to study the effect of the number of parallel joints on the size effect of rock elastic modulus. The research shows that there is a power function relationship between the elastic modulus and the number of parallel joints, and a negative exponential relationship between the elastic modulus and the rock size, and their special mathematical models are given. The paper also obtains special form of the relationships between the characteristic size of rock elastic modulus, the characteristic elastic modulus and the number of parallel joints.

The size effect on the bulk modulus of rocks has been reported by previous studies. The accuracy in selecting the parameter for the rock mechanics analysis determines further accuracy of the calculation results. Moreover, given the influence of the size effect and joint spacing, the rock bulk modulus often changes. Thus, it is essential to examine the size effect on the bulk modulus. This study elucidated the influence of rock size and parallel joint spacing on the bulk modulus using the regression analysis and 12 sets of numerical plans. The results demonstrated that the bulk modulus decreased with an increase in rock size, and the curve represents an exponential function. The bulk modulus linearly increased as the parallel joint spacing increased. Furthermore, the characteristic size of the bulk modulus linearly decreased as the parallel joint spacing increased. In contrast, the characteristic bulk modulus linearly increased as the parallel joint spacing increased. The specific forms of these relationships were also elucidated in this study.

Joint roughness coefficients (JRCs) influence the shear and characteristic strengths of structural planes; however, the relationship model of this influence is yet to be derived. This study investigates 11 numerical simulation programs using a realistic failure process analysis software. The influence of size and JRC on the shear strengths of the structural planes was studied. The stress-strain curves of different JRCs and their sizes were analyzed. Mathematical models of the shear strength of structural planes and JRC and sizes were formulated and proposed, and their expressions were obtained. Moreover, mathematical models of JRC and the characteristic size and strength of the structural planes were established.

Xincheng Gold Mine is taken as an example to investigate the ground subsidence that results from filling. Both numerical simulations and simulation experiments are conducted to simulate the deformation process at the stope roof and bottom from excavation and filling. The assumption of macroscopic continuity from traditional continuum mechanics models is overcome. The simulation results demonstrate that the ground subsidence is slowed due to filling. The total trends of the top and bottom displacements are sinkable and upturned, respectively. Moreover, with an increased buried depth and lateral pressure coefficient, the displacements of the top and bottom of the stope increase as well. The characteristics and evolution of the displacement vector field of the rock mass are macroscopically and microscopically studied over the excavation progress. This provides technical support for stope safety production.

The existence of parallel joints has an impact on the size effect of the uniaxial compressive strength of rock, but the relationship is yet to be obtained. In this paper, the influence of parallel-joint spacing on the size effect and characteristic size of rock uniaxial compressive strength is studied by establishing five types of parallel-joint-spacing simulation schemes. The influence of parallel-joint spacing on the size effect of rock uniaxial compressive strength is explored by analyzing the stress-strain curves of rocks with different parallel-joint spacings and rock sizes. The relationship between the uniaxial compressive strength and the size of the rock with parallel joints and its special mathematical model are obtained, and the particular form of the compressive-strength characteristic size and parallel-joint spacing is obtained.

The number of parallel joints has an impact on the size effect of the uniaxial compressive strength and characteristic strength of a rock; however, the relationships between them are yet to be derived. We studied the influence of the number of joints and rock size on the uniaxial compressive strength of the rock. This study established ten numerical simulation programs using numerical simulations and the RFPA software. Stress–strain curves of different numbers of parallel joints and sizes of rocks were analyzed. Relationships between the uniaxial compressive strength and number of parallel joints and rock size were proposed, and their special functions were obtained. Mathematical models between rock characteristic size, rock characteristic strength and the number of parallel joints were established. Simulations of the verification program confirmed that these relationships are still applicable after the angle of parallel joints changes.

To study the mechanism of surface collapse and crack evolution in a roadway chain failure process in the pillar recovery of Hongling lead zinc ore in Inner Mongolia Province, China, microseismic monitoring technology, moment tensor theory, and numerical simulation are used for the inversion of rock mass fracturing, the destruction type classification of crack, and the mechanism of surrounding rock. Research shows the following: (1) the rock mass fracturing is first produced within the +955 m level, before extending through the hanging wall to the ground surface. Then, many shear failures occur in the ground surface of the footwall, extending downwards in an arc-shaped path to the +905 m level. Finally, the surface gradually collapses with large-scale shear failures. (2) The mechanism of surface collapse is as follows: after the recovery of pillars in the +905 m level, tensile cracks generated in the top of orebody #2 extend upwards and obliquely. Analogously, shear cracks are generated in the top of orebody #1, extending upwards. After the recovery of pillars in the +855 m level, the marble interlayer is destroyed and sinks, and many tensile cracks and shear cracks exist and incise in the ground surface, which cause the ground surface to collapse. (3) The mechanism of crack evolution is as follows: after the recovery of 5107 pillars, the footwall haul road in the +905 m level was damaged and collapsed by the cut-through cracks. Those cracks then continue to extend upwards and converge with the slanting shear cracks in the +905 m level, which form a triangular failure in the footwall rock. Finally, the failure causes the tensile and shearing cracks in the haulage way of the +955 m level to extend and connect, which forms the haulage way chain failure.

The pandemic has reinforced older adults' reliance on their homes and the concept of “aging in place”. Changes like reduced physical strength and cognitive deficit, however, have heightened the challenge of simple tasks like obstacle crossing among older adults, let alone when older adults cannot perceive the surroundings well during the nighttime. The study is, therefore, to evaluate the impact of lighting on older adults' obstacle-crossing behavior during the nighttime. Twenty-seven older adults (81 ± 6 yrs., 171 ± 12 cm, 75 ± 20 kg, 14 females) were recruited. Participants were asked to cross over the obstacle in a dark residential environment under point or line light. We found that the line light tended to (1) induce more external rotation of the trailing hip (p = 0.037) and more internal rotation of the leading ankle (p

Plant growth regulators have been used in the cultivation of medicinal plants to increase yield, but the existing regulators decreased the content of active constituents which benefit human health. Therefore, it is necessary to find a new growth regulator to achieve the win-win goal of increasing yield and improving active constituents’ accumulation. The potential of replacing chlorocholine chloride with a new humic acid-based growth regulator was evaluated by measuring the yield and active constituents’ accumulation of Codonopsis pilosula. Three treatments including water (CK), chlorocholine chloride (T1) and humic acid regulator (T2) were applied by foliar spraying. Among them, both chlorocholine chloride and humic acid regulator belong to biostimulant. The result showed that the root yield in T1 and T2 were significantly increased by 59.1% and 54.9% compared with CK, respectively, and there was no significant difference between T1 and T2. Compared with CK, the yields of lobetyolin, syringin and atractylenolide III of Codonopsis pilosula were significantly decreased by 6.3%, 7.3% and 13.0% in T1, but were significantly increased by 22.8%, 14.8% and 32.0% in T2, respectively. Redundancy analyses showed that photosynthetic rate, sucrose phosphoric acid synthetase and phosphomannomutase had higher degree of explanation for yield and quality. Linear regression results indicated that photosynthetic rate and phosphomannomutase were the main factors to affect yield and active constituents yields, respectively. In addition, the output-input ratios based on the yields of polysaccharides, lobetyolin, syringin and atractylenolide III of Codonopsis pilosula in T2 was significantly increased by 6.5%, 15.2%, 8.7% and 31.2% respectively as compared with T1. Overall, compared with water treatment, both chlorocholine chloride and humic acid regulator treatments can increase the root yield of Codonopsis pilosula. Compared with chlorocholine chloride, humic acid regulator can improve the yield of active constituents and economic benefits of Codonopsis pilosula. This study indicated that reasonable selection of plant growth regulators is of great significance for achieving a win-win goal of increasing the root yield and active constituents of medicinal plants.

Abstract Recent works have shown that by using time‐modulated arrays (TMAs), directional modulation (DM) physical‐layer secured transmitters for orthogonal frequency‐division multiplexing (OFDM) wireless data transfer can be constructed. In this paper, three‐state TMAs are introduced for OFDM DM systems which allow more flexible manipulation of the injected orthogonal artificial noise and hence improve security. In particular, this paper presents for the first time both static and dynamic three‐state time‐modulated OFDM DM systems. Simulated bit error rate (BER) spatial distributions are shown for various system configurations in order to illustrate representative examples of secrecy performance enhancement that can be achieved by the proposed transmitter arrangement.

Abstract Backscatter communication, an emerging ultra‐low‐power wireless communication paradigm, has been studied as a promising solution for wireless communications in some Internet‐of‐Things (IoT) applications. The required ubiquitous data transmission in the IoT world is demanding information security. Different from mathematical encryption at higher protocol layers, the directional modulation (DM) technology can provide physical‐layer wireless security, which does not require digital and computation resources that are otherwise scarce in low‐power IoT devices. In this paper, a synthesis‐free Van‐Atta backscatter array is constructed and studied. The authors show that a Van‐Atta array can be made to project orthogonal interference upon the backscattered signals in the radio frequency domain. The design details of the Van‐Atta DM array are elaborated, and its efficacy is validated via bit error rate simulations.

The continued growth of the industrial Internet of Things (IoT) paves the way for the fifth industrial revolution (Industry 5.0), which is expected to further enhance the wireless connectivity and human machine collaboration. Nonetheless, Industry 5.0 will inevitably face the great challenges such as large scale connectivity and explosive data traffic because of the proliferation of IoT devices. To meet these challenges, we propose a novel non-orthogonal multiple access (NOMA)-based overlay cognitive radio (OCR) network for Industry 5.0. Specifically, the hybrid full-duplex (FD)/ half-duplex (HD) mode at the secondary user (SR) is adopted and in-phase and quadrature phase imbalance (IQI) is introduced to better comply with the practical scenarios. We investigate the outage probability (OP) and ergodic sum rate (ESR) of the considered network with the Nakagami-m channels. Extensive simulation experiments are performed to verify the accuracy of the analysis. From the simulation results, we can conclude: i) Increasing the signal-to-noise ratio (SNR), OP decreases but ESR increases and tends to a fixed value at high SNR regimes, indicating that the existence of IQI leads to a ceiling for the ESR; ii) The primary system has higher reliable performance at low SNR regions when SR is in FD mode, and for ergodicity, the system with FD relay is superior to HD relay; iii) The reliable performance of OMA system for primary users will be better since there is no interference at the relay.

Fibroblast-like synoviocytes (FLSs) play a crucial role in rheumatoid arthritis (RA) pathogenesis. While miRNA (miR)-506 has been implicated in the progression of multiple diseases, its role in RA remains to be explored. The present study evaluated the function of miR-506 in the regulation of RA-FLSs. FLSs were prepared from RA and healthy synovial tissues. The expression of miR-506 was measured by quantitative real time PCR (qRT-PCR). The effects of miR-506 on RA-FLSs proliferation and apoptosis were detected by cell counting Kit-8 and flow cytometry assays, respectively. The determination of TNF-α, IL-6, and IL-1β concentrations in RA-FLSs supernatant were done by ELISA. The levels of miR-506 were detected to be significantly lower in the synovial tissues and FLSs of RA than in the synovial tissues and FLSs of healthy controls. The miR-506 up-regulation in RA-FLSs significantly inhibited the proliferation and promoted cell cycle arrest at the G0/G1 phase. The overexpression of miR-506 induced apoptosis, along with an increase in activities of caspase-3 and -8. A target gene Toll-like receptor 4 (TLR4) under the direct regulation of miR-506 was identified through the luciferase assay, qRT-PCR and western blot analysis. Forced overexpression of TLR4 in the rescue experiments showed that TLR4 effectively reversed the effect on proliferation and apoptosis in miR-506-overexpressing RA-FLSs. Thus, miR-506 may be a potential target for RA prevention and therapy of RA. [ABSTRACT FROM AUTHOR]

Background: Semi-autonomous vehicles still require human drivers to take over when the automated systems can no longer perform the driving task. Objective: The goal of this study was to design and test the effects of six meaningful tactile signal types, representing six driving scenarios (i.e., navigation, speed, surrounding vehicles, over the speed limit, headway reductions, and pedestrian status) respectively, and two pattern durations (lower and higher urgencies), on drivers’ perception and performance during automated driving. Methods: Sixteen volunteers participated in an experiment utilizing a medium-fidelity driving simulator presenting vibrotactile signals via 20 tactors embedded in the seat back, pan, and belt. Participants completed four separate driving sessions with 30 tactile signals presented randomly throughout each drive. Reaction times (RT), interpretation accuracy, and subjective ratings were measured. Results: Results illustrated shorter RTs and higher intuitive ratings for higher urgency patterns than lower urgency patterns. Pedestrian status and headway reduction signals were associated with shorter RTs and increased confidence ratings, compared to other tactile signal types. Lastly, among six tactile signals, surrounding vehicle and navigation signal types had the highest interpretation accuracy. Conclusion: These results will be used as preliminary data for future studies that aim to investigate the effects of meaningful tactile displays on automated vehicle takeover performance in complex situations (e.g., urban areas) where actual takeovers are required. The findings of this study will inform the design of next-generation in-vehicle human-machine interfaces.

Abstract The future sixth generation (6G) is going to face the significant challenges of massive connections and green communication. Recently, reconfigurable intelligent surfaces (RIS) and non-orthogonal multiple access (NOMA) have been proposed as two key technologies to solve the above problems. Motivated by this fact, we consider a downlink RIS-aided NOMA system, where the source aims to communicate with the two NOMA users via RIS. Considering future network supporting real-time service, we investigate the system performance with the view of effective capacity (EC), which is an important evaluation metric of delay sensitive systems. Specifically, we derive the analytical expressions of the EC of the near and far users. To obtain more useful insights, we deduce the analytical approximation expressions of the EC in the low signal-to-noise-ratio approximation by utilizing Taylor expansion. Moreover, we provide the results of orthogonal multiple access (OMA) for the purpose of comparison. It is found that (1) The number of RIS components and the transmission power of the source have important effects on the performance of the considered system; (2) Compared with OMA, NOMA system has higher EC due to the short transmission time.

Abstract This paper studies a novel Radar and wireless communication fusion system namely, RadCom, using orthogonal frequency division multiplexing index modulation waveforms. From the communication perspective, information is conveyed not only through modulated orthogonal frequency division multiplexing subcarriers but also by the active subcarrier indices that are dynamically updated at the transmitted symbol rates. When compared with conventional orthogonal frequency division multiplexing communication systems, only a subset of subcarriers is activated in the proposed orthogonal frequency division multiplexing index modulation system, which reduces signal peak‐to‐average ratios, leading to enhanced power amplifier efficiency. From the Radar sensing perspective, the Radar range‐velocity profile obtained using compressed sensing approach is simulated and presented. It is shown that orthogonal frequency division multiplexing index modulation RadCom system can enhance the transmission data rates when low‐order modulation schemes are adopted e.g. binary phase shift keying, and maintain similar Radar performance compared with the orthogonal frequency division multiplexing counterpart when the system is carefully designed.

In this paper, we propose a new architecture and provide performance analysis for frequency diverse array (FDA) Radar combined with the index modulation (IM) techniques. Here, the IM concept is applied upon frequency offsets in an FDA. Information is transmitted by a dynamically selected subset of antenna element indices applying predefined carrier frequency offsets, which generate different radiation patterns. It is shown that this enables the capability for simultaneous wireless communication and FDA Radar that has the range-angle coupling issue resolved.

BackgroundEmerging evidence indicates that impaired angiogenesis may contribute to hypertension‐induced cardiac remodeling. The nicotinamide adenine dinucleotide–dependent deacetylase Sirtuin 3 (SIRT3) has the potential to modulate angiogenesis, but this has not been confirmed. As such, the aim of this study was to examine the relationship between SIRT3‐mediated angiogenesis and cardiac remodeling. Methods and ResultsOur experiments were performed on SIRT3 knockout and age‐matched wild‐type mice infused with angiotensin II (1400 ng/kg per minute) or saline for 14 days. After angiotensin II infusion, SIRT3 knockout mice developed more severe microvascular rarefaction and functional hypoxia in cardiac tissues compared with wild‐type mice. These events were concomitant with mitochondrial dysfunction and enhanced collagen I and collagen III expression, leading to cardiac fibrosis. Silencing SIRT3 facilitated angiotensin II–induced aberrant Pink/Parkin acetylation and impaired mitophagy, while excessive mitochondrial reactive oxygen species generation limited angiogenic capacity in primary mouse cardiac microvascular endothelial cells. Moreover, SIRT3 overexpression in cardiac microvascular endothelial cells enhanced Pink/Parkin‐mediated mitophagy, attenuated mitochondrial reactive oxygen species generation, and restored vessel sprouting and tube formation. In parallel, endothelial cell–specific SIRT3 transgenic mice showed decreased fibrosis, as well as improved cardiac function and microvascular network, compared with wild‐type mice with similar stimuli. ConclusionsCollectively, these findings suggest that SIRT3 could promote angiogenesis through attenuating mitochondrial dysfunction caused by defective mitophagy.