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Abstract Background Laser balloon (LB) pulmonary vein isolation (PVI) is an established ablation technique for atrial fibrillation (AF). We report long‐term follow‐up and procedural data of LB‐PVI and we compare the first and second LB generation. Methods Patients undergoing LB ablation with first‐ (LB1) or second‐generation LB (LB2) for AF were retrospectively enrolled and divided into two groups. Procedural endpoint was complete PVI. Clinical success was defined as no recurrence of AF/atrial tachycardia after a 90 days blanking period. Results 538 patients were included (age 66 ± 10 years, 58% paroxysmal AF), 427 in LB1 and 111 in LB2. 2079 PVs were targeted and 2073 (99.7%) were successfully isolated; 2027 (97.5%) using solely the LB. Additional touch‐up ablation was limited (46 PVs; 2.2%) with no difference between the groups. Procedural (LB1: 120 ± 33 minutes vs. LB2: 99 ± 22 min; p

Abstract The fractured surrounding rocks of roadways pose major challenges to safe mining. Grouting has often been used to reinforce the surrounding rocks to mitigate the safety risks associated with fractured rocks. The aim of this study is to develop highly efficient composite ultrafine cement (CUC) grouts to reinforce the roadway in fractured surrounding rocks. The materials used are ultrafine cement (UC), ultrafine fly ash (UF), ultrafine slag (US), and additives (superplasticizer [SUP], aluminate ultrafine expansion agent [AUA], gypsum, and retarder). The fluidity, bleeding, shrinkage, setting time, chemical composition, microstructure, degree of hydration, and mechanical property of grouting materials were evaluated in this study. Also, a suitable and effective CUC grout mixture was used to reinforce the roadway in the fractured surrounding rock. The results have shown that the addition of UF and US reduces the plastic viscosity of CUC, and the best fluidity can be obtained by adding 40% UF and 10% US. Since UC and UF particles are small, the pozzolanic effect of UF promotes the hydration reaction, which is conductive to the stability of CUC grouts. In addition, fine particles of UC, UF, and US can effectively fill the pores, while the volumetric expansion of AUA and gypsum decreases the pores and thus affects the microstructure of the solidified grout. The compressive test results have shown that the addition of specific amounts of UF and US can ameliorate the mechanical properties of CUC grouts. Finally, the CUC22‐8 grout was used to reinforce the No. 20322 belt roadway. The results of numerical simulation and field monitoring have indicated that grouting can efficaciously reinforce the surrounding rock of the roadway. In this research, high‐performance CUC grouts were developed for surrounding rock reinforcement of underground engineering by utilizing UC and some additives.

Abstract The classroom video has a complex background and dense targets. This study utilizes small object detection technology to analyze and evaluate students’ behavior in the classroom, aiming to objectively and accurately assess classroom quality. Firstly, noise is removed from the images using a median filter, and the contrast of the images is enhanced through histogram equalization. Label smoothing is applied to reduce the model’s sensitivity to labels. Then, features are extracted from the preprocessed images, and multi-scale feature fusion is employed to enhance semantic expression across multiple scales. Finally, a combination loss function is utilized to improve the accuracy of multi-object recognition tasks. Real-time detection of students’ behaviors in the classroom is performed based on the small object detection model. The average head-up rate in the classroom is calculated, and the quality of teaching is evaluated and analyzed. This study explores the methods and applications of small object detection technology based on actual teaching cases and analyzes and evaluates its effectiveness in evaluating the quality of higher education classroom teaching. The research findings demonstrate the significant importance of small object detection technology in effectively evaluating students’ learning conditions in higher education classrooms, leading to improved teaching quality and personalized education.

Incorporating inorganic fillers into solid polymer electrolytes (SPEs) to construct composite polymer electrolytes (CPEs) serves as an effective strategy to comprehensively enhance the properties of solid electrolytes. Herein, a CPE is fabricated by integrating Li6PS5Cl particles into polycaprolactone (PCL). The addition of active fillers could effectively weaken the crystallization of polymer and increase the ionic conductivity of the solid electrolyte. In particular, the PCL-based polymer electrolyte with 3% Li6PS5Cl (PCL-3) exhibits an excellent ionic conductivity of 1.36×10−4 S cm−1 at room temperature, which is one order higher than that of PCL polymer solid electrolyte. And it achieves a high critical current density of 2.2 mA cm−2 with a capacity of 2.2 mAh cm−2. The assembled Li symmetric battery can cycle steadily for more than 3000 h at 0.5 mA cm−2 under room temperature. The LiFePO4/PCL-3/Li all-solid-state battery maintains a capacity of 125.3 mAh g−1 after 400 cycles at 0.2 C under room temperature. Notably, the LiFePO4//Li battery also shows stable cycling at 40 °C, exhibiting high reversible specific capacities of 156.7 mAh g−1 and 126.3 mAh g−1 with a retention rate of 97.15% and 94.6% at 0.2 C and 0.5 C after 100 cycles, respectively, showing promising application prospects for all-solid-state lithium metal batteries.

Simultaneously manipulating multiple physical fields plays an important role in the increasingly complex integrated systems, aerospace equipment, biochemical productions, etc. For on-chip systems with high integration level, the precise and efficient control of the propagation of electromagnetic waves and heat fluxes simultaneously is particularly important. In this study, we propose a graphical designing method (i.e., thermal-electromagnetic surface transformation) based on thermal-electromagnetic null medium to simultaneously control the propagation of electromagnetic waves and thermal fields according to the pre-designed paths. A thermal-electromagnetic cloak, which can create a cloaking effect on both electromagnetic waves and thermal fields simultaneously, is designed by thermal-electromagnetic surface transformation and verified by both numerical simulations and experimental measurements. The thermal-electromagnetic surface transformation proposed in this study provides a new methodology for simultaneous controlling on electromagnetic and temperature fields, and may have significant applications in improving thermal-electromagnetic compatibility problem, protecting of thermal-electromagnetic sensitive components, and improving efficiency of energy usage for complex on-chip systems.

Abstract Objective We aimed to assess the effect of SGLT2i on arrhythmias by conducting a meta-analysis using data from randomized controlled trials(RCTs). Background Sodium-glucose co-transporter 2 inhibitors (SGLT2i) have shown cardioprotective effects via multiple mechanisms that may also contribute to decrease arrhythmias risk. Methods We searched in databases (PubMed, Embase, Cochrane Library, and clinicaltrials.gov) up to April 2023. RCTs comparing SGLT2i with placebo were included. The effects of SGLT2i on atrial fibrillation(AF), atrial flutter(AFL), composite AF/AFL, ventricular fibrillation(VF), ventricular tachycardia(VT), ventricular extrasystoles(VES), sudden cardiac death(SCD) and composite VF/VT/SCD were evaluated. Results 33 placebo-controlled RCTs were included, comprising 88,098 patients (48,585 in SGLT2i vs. 39,513 in placebo). The mean age was 64.9 ± 9.4 years, 63.0% were male. The mean follow-up was 1.4 ± 1.1 years. The pooled-results showed that SGLT2i was associated with a significantly lower risk of AF [risk ratio(RR): 0.88, 95% confidence interval(CI) 0.78–1.00, P = 0.04] and composite AF/AFL (RR: 0.86, 95%CI 0.77–0.96, P = 0.01). This favorable effect appeared to be substantially pronounced in patients with HFrEF, male gender, dapagliflozin, and > 1 year follow-up. For SCD, only in heart failure patients, SGLT2i were found to be associated with a borderline lower risk of SCD (RR: 0.67, P = 0.05). No significant effects of SGLT2i on other ventricular arrhythmic outcomes were found. Conclusions SGLT2i lowers the risks of AF and AF/AFL, and this favorable effect appeared to be particularly pronounced in patients with HFrEF, male gender, dapagliflozin, and longer follow-up (> 1 year). SGLT2i lowers the risk of SCD only in heart failure patients. Graphical Abstract

In order to meet the needs of safe production in coal mines, many roadways are arranged in the bottom plate of coal seams, such as part of transportation alleys，drainage roadways, and gas extraction roadways. The mining stress generated by the working face causes the stress increase of the surrounding rock of the floor roadway through the transmission of the floor rock strata. It exacerbates the deformation of the surrounding rock of the floor roadway, which is easy to cause permanent support failure, roof sinking, dropsy at the bottom of the roadway, convergence of the two gangs, and other damages. In response to this, a control technology is proposed to implement hydraulic fracturing in the stress transfer path, creating a network of hydraulic fractures with a certain spatial pattern in the designated area, forming a fractured weak structural body, realizing stress transfer within the area, thus reducing the stress within the area of the roadway, and controlling the stability of the perimeter rock of the roadway, and through theoretical analysis and field engineering verification, the mechanical mechanism of stress transfer of weak structures in floor dynamic pressure roadway fracturing is revealed, the corresponding mechanical model is established, and the influence factors such as reasonable location and range of weak structures are solved. The results show that: ① Fracturing weak structure causes obvious changes in local stress field, and there are stress increasing zone and stress decreasing zone, and the stress decreasing zone is mainly distributed in the direction of the connection between weak structure and mining stress, mainly concentrated in an arch range; Due to the expansion effect, the stress concentration occurs in the vertical direction of the stress source, and the stress rise area appears. ② The magnitude of maximum principal stress change is related to the long axis L, short axis H, distance P to the roadway, horizontal angle β to the roadway line, strength C and internal friction angle α of the fractured layer, and damage variable D of the fracture in the weak structural body of the fracture. ③ The proposed method is used to design the pressure relief scheme of 103 belt concentrated roadway in Yuandian No. 1 Mine of Huaibei Mining Group. The engineering application results show that the deformation rate of roadway under dynamic pressure of floor is significantly reduced, and the rationality of the stress transfer model of fractured weak structure in roadway under strong dynamic pressure of floor is verified.

The crystal structure and morphology of photocatalysts play a crucial role in determining their photocatalytic performance. In this study, we synthesized and investigated 1D/2D Bi2S3 as a potential visible-light-activated photocatalyst for the reduction of aqueous Cr(VI). The 1D/2D Bi2S3 was synthesized using hydrothermal synthesis technique by heating Bi2(H2O)2(SO4)2(OH)2 precursor and sodium sulfide at 190 ℃ for 24 h, where the molar ratio of Bi to S elements in the reaction reagents was changed from 1:6 to 2:3. The structure, composition, and optoelectronic properties of the prepared Bi2S3 were characterized using X-ray diffraction, UV-vis diffuse reflectance spectra, field emission scanning electron microscopy, electrochemical impedance spectra, and transient photocurrent. It is shown that the prepared orthorhombic Bi2S3 has full-spectrum photoresponsivity. Bi2S3-B with 1D/2D heterogeneous structure exhibits the lowest charge carrier transport resistance, and its photocurrent intensity is nearly twice that of Bi2S3-C. It demonstrates the highest photocatalytic activity in visible-light photocatalytic reduction of aqueous Cr(VI), with a reduction rate of 54.5% after 140 minutes of light exposure. According to the bandgap of Bi2S3 and radical scavenger experiments, a reaction mechanism for the photocatalytic reduction of Cr(VI) by Bi2S3 was proposed. Furthermore, the results highlight the economic and environmentally friendly nature of the hydrothermal synthesis method using homemade precursors, which allows for the regulation of Bi2S3 morphology and the enhancement of its visible photocatalytic activity. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

According to different geological conditions and engineering disturbance, three dimensional numerical models of anchored jointed rock mass with two kinds of boundary conditions of constant normal load (CNL) and constant normal stiffness (CNS) were constructed considering the ductility damage of rockbolt, the stiffness degradation of grouting layer and the joint surface roughness. The effects of anchorage angle, joint surface morphology, and boundary conditions on the shear performance of anchorage system were analyzed, and the failure characteristics under different working conditions were revealed. Finally, the analytical solution of shear strength of anchored system was established. Results show that the larger the anchorage angle is, the more serious the necking phenomenon of rockbolt will be. The damage degree of the bonding layer and the horizontal displacement of the bedding rock mass decrease with the increase of the joint surface roughness. The CNL condition is to instantaneously apply high normal stress, and the CNS condition is to gradually form a high normal stress environment through the superposition of increment on the basis of the initial value, which can resist greater transverse load. This is equivalent to enhancing the ductility of the rockbolt. The shear strength of the system increases with the increase of normal stress and normal stiffness. Ignoring the normal stiffness will underestimate the shear strength.

Biochar material is a renewable adsorbent widely used for treating contaminated wastewater. The hydrothermal carbon (HTC) were prepared from low polymeric sugars and low concentration glucose under hydrothermal carbonization reactions without using dispersants. The composition and structure of the biochar produced were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Raman spectroscopy (Raman), and N2 adsorption-desorption, indicating that amorphous graphitic carbon was obtained. Experimental results from the static adsorption of Cr(VI)-contaminated wastewater showed that HTCP-2 exhibited the highest adsorption capacity for Cr(VI), with a maximum adsorption capacity of 22.62 mg.g−1.The adsorption Cr(VI), MB, and RhB by the synthesized biochar all conformed to the pseudo-second-order kinetic model and Freundlich isotherm, suggesting a multilayer chemical adsorption process. Additionally, the synthesized HTC surface is enriched with a significant amount of oxygen-rich functional groups, which also has good adsorption performance for cationic dyes. Furthermore, the test results of fluorescence, photocurrent, and impedance indicate that HTCP-2 possesses the ability to generate and separate photoinduced charge carriers. This implied that HTCP-2 can be used for the preparation of adsorption photocatalysts, which effectively remove environmental pollutants through the synergistic effect of adsorption-photocatalysis. This study provides a research foundation for advancing water treatment technologies. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Abstract Cleats are the main channels for fluid transport in coal reservoirs. However, the microscale flow characteristics of both gas and water phases in primary cleats have not been fully studied as yet. Accordingly, the local morphological features of the cleat were determined using image processing technology and a transparent cleat structure model was constructed by microfluidic lithography using the multiphase fluid visualization test system. Besides, the effect of microchannel tortuosity characteristics on two‐phase flow was analyzed in this study. The results are as follows: (1) The local width of the original cleat structure of coal was strongly nonhomogeneous. The cleats showed contraction and expansion in the horizontal direction and undulating characteristics in the vertical direction. (2) The transient flow velocity fluctuated due to the structural characteristics of the primary cleat. The water‐driven gas interface showed concave and convex instability during flow, whereas the gas‐driven water interface presented a relatively stable concave surface. (3) The meniscus advanced in a symmetrical pattern in the flat channel, and the flow stagnated due to the influence of undulation points in a partially curved channel. The flow would continue only when the meniscus surface bypassed the stagnation point and reached a new equilibrium position. (4) Enhanced shearing at the gas–liquid interface increased the gas‐injection pressure, which in turn increased residual liquids in wall grooves and liquid films on the wall surface.

In order to better understand the formation of thrust fault in coal measures and how it makes a difference on mining-induced disasters, a simulation system for the formation process of a new type of thrust fault in coal measures has been improved, which adopts hydraulic servo control to realize the double precise control of displacement and stress. During the coal seam mining test, only part of the transparent plate at the mining position behind the coal seam is removed to keep the internal structural stress from being released. The system is used to carry out the experimental research on the formation of thrust fault in coal measures and coal winning operation. The results indicate that the displacement of each rock stratum can be divided into three regions during the formation of thrust fault: displacement region, compression region and stability region. The maximum displacement of the measuring point is in the displacement region and the relative displacement in various measuring points is small, its extents increase with the decrease of the burial depth of rock stratum. The displacement of measuring points in the compression region gradually decreases from hanging wall to footwall, and the displacement and relative displacement in the stability region are both the smallest, and their extents decrease with the burial depth of the rock stratum. The displacement angle of hanging wall measuring point increases gradually as the measuring point approaches the fault plane, reaching a maximum of 87.5°. In the formation of thrust fault, the horizontal stress on the roof and floor increases and then decreases, and the horizontal stress on the hanging wall is greater than that at the foot wall. The vertical stress of the coal roof in the foot wall of the fault tends to increase, while the vertical stress of the coal seam roof in the hanging wall of the fault tends to present the change of increase−decrease – increase. When comparing and analyzing the in-situ stress measurements of 22 domestic thrust faults in coal measures, it suggests that the ratio of maximum horizontal principal stress to vertical principal stress is in the range of 1−4 in the tectonic zones of thrust fault. After the thrust fault is stabilized in the test, the k of the hanging wall and foot wall is stable between 2−3. After the formation of thrust fault in coal measures, in the footwall coal seam mining process, the vertical and horizontal stresses in the coal seam roof both tend to increase and then decrease. Under the superposition of tectonic stress and mining-induced stress, the rock stratum near the fault produces stress aggregation, and its peak stress is greater. The conditions mentioned above lead to more violent movement of the overlying strata after coal winning. The coal winning can be divided into the cyclic evolution stage of rock pressure and the dynamic disaster stage. In the cyclic evolution stage of rock pressure, the vertical stress of wall and working face increases significantly periodically, and the high stress area migrates to the footwall structure coal. In the dynamic disaster stage, the working face is already in high stress area, which is easy to cause coal mine dynamic disasters such as rock burst.

Abstract Catheter ablation is the most effective treatment for atrial fibrillation (AF). Electrical pulmonary veins isolation (PVI) forms the cornerstone ablation strategy. Radiofrequency (RF) in combination with 3D mapping system is the traditional ablation approach to treat AF. As a single-shot ablation system, cryoballoon (CB) has been an established ablation modality to facilitate PVI procedure. As a novel non-thermal single-shot ablation technology, pulsed field ablation (PFA) has its unique biophysical profile. Recent studies have demonstrated that PFA allows for efficient and durable PVI. However, the manipulation of single-shot ablation catheter may be different from the conventional point-by-point RF ablation catheter; ablation catheter with fixed size may have practical difficulties in variable anatomy and different clinical scenarios. The present article focuses on the technical aspects, describes the procedural approaches and illustrates the practical techniques of using CB and PFA for PVI, ultimately with the purpose to facilitate the ablation procedure and improve the patients’ clinical outcome.

Abstract Background Nearly one fourth of patients with pancreatic ductal adenocarcinoma (PDAC) occur to liver metastasis after surgery, and liver metastasis is a risk factor for prognosis for those patients with surgery therapy. However, there is no effective way to predict liver metastasis post-operation. Method Clinical data and preoperative magnetic resonance imaging (MRI) of PDAC patients diagnosed between July 2010 and July 2020 were retrospectively collected from three hospital centers in China. The significant MRI radiomics features or clinicopathological characteristics were used to establish a model to predict liver metastasis in the development and validation cohort. Results A total of 204 PDAC patients from three hospital centers were divided randomly (7:3) into development and validation cohort. Due to poor predictive value of clinical features, MRI radiomics model had similar receiver operating characteristics curve (ROC) value to clinical-radiomics combing model in development cohort (0.878 vs. 0.880, p = 0.897) but better ROC in validation dataset (0.815 vs. 0.732, p = 0.022). Radiomics model got a sensitivity of 0.872/0.750 and a specificity of 0.760/0.822 to predict liver metastasis in development and validation cohort, respectively. Among 54 patients randomly selected with post-operation specimens, fibrosis markers (α-smooth muscle actin) staining was shown to promote radiomics model with ROC value from 0.772 to 0.923 (p = 0.049) to predict liver metastasis. Conclusion This study developed and validated an MRI-based radiomics model and showed a good performance in predicting liver metastasis in resectable PDAC patients.

Abstract Aeolian sand (AS) can become a green resource for concrete after the reasonable utilization. Study the evolution of AS concrete (ASC) capillary water absorption (CWA) under freeze–thaw (FT) conditions is of great significance for its popularization and application. One-dimensional (1D) CWA test was performed to analyze the effects of AS and freeze–thaw cycling (FTC) on concrete water absorption characteristics. Pore relative saturation (PRS) and pore saturation were defined to reveal the influence mechanism of AS content on concrete water absorption under FT conditions and predict the moisture distribution in damaged ASC combining with the capillary mechanics theory. The results showed that concrete frost resistance increased with increased AS content and the optimal frost resistance achieved with 100% AS replacement despite its low strength. The initial water absorption rate (WAR), pore saturation, and saturation speed of the ASC decreased with increased AS, while the PRS increased with low AS content but decreased with excessive AS. The water absorption depth increased with increased mass and dynamic elastic modulus loss rates. The mechanism regarding why excessive AS improved concrete frost resistance lay in its internal pore structure and large pore ratio, which reduced pore content that can easily absorb water, enclosed a higher volume of air bubbles, and easily formed "air locking," thereby increasing water transmission resistance and forming long transmission paths during the process of CWA.

Abstract Background Intrahepatic cholangiocarcinoma (ICC) is a malignant disease characterized by onset occult, rapid progression, high relapse rate, and high mortality. However, data on how the tumor microenvironment (TME) regulates ICC metastasis at the transcriptomic level remains unclear. This study aimed to explore the mechanisms and interactions between hepatocytes and ICC cells. Methods We analyzed the interplay between ICC and liver microenvironment through cytokine antibody array analysis. Then we investigated the role of N6-methyladenosine (m6A) modification and the downstream target in vitro, in vivo experiments, and in clinical specimens. Results Our study demonstrated that cytokine CCL3, which is secreted by hepatocytes, promotes tumor metastasis by regulating m6A modification via vir-like m6A methyltransferase associated (VIRMA) in ICC cells. Moreover, immunohistochemical analyses showed that VIRMA correlated with poor outcomes in ICC patients. Finally, we confirmed both in vitro and in vivo that CCL3 could activate VIRMA and its critical downstream target SIRT1, which fuels tumor metastasis in ICC. Conclusions In conclusion, our results enhanced our understanding of the interaction between hepatocytes and ICC cells, and revealed the molecular mechanism of the CCL3/VIRMA/SIRT1 pathway via m6A-mediated regulation in ICC metastasis. These studies highlight potential targets for the diagnosis, treatment, and prognosis of ICC.

Scientific and reasonable application of potassium fertilizer is an important agronomic measure to achieve high yield and high quality of sweetpotato, and it is of great significance to determine the appropriate amount of potassium fertilizer in the field. For this we constructing a model of the critical K dilution curve (CKDC) of sweetpotato under different N levels to determine crop nutritional statuses. In this study, a 3-year field experiment was conducted in Zhejiang Province in China, using two nitrogen levels (N0: 0 kg ha−1 and N1: 120 kg ha−1) and five K fertilization rates (K0: 0, K1: 75, K2: 150, K3: 225, K4: 300 kg ha−1) for two sweetpotato cultivars of ‘Shang 19’ and ‘Yan 25’. Plant dry matter first increased and then decreased and the K concentration increased continuously with an increase in K application rate. The required amount of K fertilizer to achieve maximum sweetpotato yield under high N conditions was greater than that under low nitrogen conditions. A new CKDC based on dry matter and K concentration was created to assess K nutrition in sweetpotato. At two N levels, CKDC was expressed by the negative power function equation, aboveground: Kc(N0)=5.30W-0.463, R2 = 0.79, and Kc(N1)=4.23W-0.298, R2 = 0.78, under-ground: Kc(N0)=1.38W-0.125, R2 = 0.81, and Kc(N1)=1.32W-0.132, R2 = 0.72;whole-plant: Kc(N0)=4.31W-0.421, R2 = 0.80; Kc(N1)=3.89W-0.415, R2 = 0.79. There is no significantly different for CKDC of whole-plant and underground between N0 and N1 levels, while there is significantly different for CKDC of aboveground between N0 and N1 levels. N fertilizer can strengthen the dilution effect of K concentration, and its effect on the aboveground is greater than that on the underground and whole-plant. Then, potassium nutrition indexes were constructed to identify K nutrition status and could be used as a reliable indicator for K nutrition diagnosis of sweetpotato. The results provide a theoretical basis to improve K fertilization management and sustainability of sweetpotato.

The sealing performance of a bentonite barrier is highly dependent on its seepage characteristics, which are directly related to the characteristics of its pore structure. Based on scanning electron microscopy (SEM) and focused ion beam-SEM (FIB-SEM), the pore structure of bentonite was characterized at different scales. First, a reasonable gray threshold was determined through back analysis, and the image was binarized based on the threshold. In addition, binary images were used to analyze bentonite's pore structure (porosity and pore size distribution). Furthermore, the effects of different algorithms on the pore structure characterization were evaluated. Then, permeability calculations were performed based on the previous pore structure characteristics and a modified permeability prediction model. For permeability prediction based on the three-dimensional model, the effect of pore tortuosity was also considered. Finally, the accuracy of numerical calculations was verified by conducting macroscopic gas and alcohol permeability experiments. This approach provides a better understanding of the microscale mechanism of gas transport in bentonite and the importance of pore structures at different scales in determining its seepage characteristics.

Abstract Background Left atrial appendage (LAA) isolation (LAAI) has been described as an adjunctive ablation strategy for patients with recurrent atrial tachyarrhythmia (ATa). Objectives We compared the clinical impact of persistent durable LAAI between radiofrequency (RF)‐guided wide‐area LAAI and cryoballoon (CB)‐guided ostial LAAI. Methods Consecutive patients who underwent RF‐ or CB‐guided LAAI were retrospectively analyzed. RF‐guided LAAI was performed by combining linear ablation. CB‐guided LAAI was performed by LAA ostial ablation. Following LAAI, the patients underwent an invasive remapping study. LAA closure was conducted if persistent durability was confirmed. The procedural data, LAAI durability, and ATa recurrence were assessed. Results A total of 260 patients (RF: n = 201; CB: n = 59) undergoing LAAI were identified. The acute rate of procedural LAAI was higher in the CB group (CB:94.9% vs. RF:82.6%, p = .02) with a lower pericardial effusion incidence (CB:0% vs. RF:7.5%, p = .03). The 6‐week durable LAAI was similar between the two groups (RF:78.3% vs. CB:66.0%, p = .103). During follow‐up, one gastrointestinal bleeding and four stroke events including one subsequent intracranial bleeding leading to death occurred in the RF group, while one gastrointestinal bleeding occurred in the CB group. The 1‐year ATa recurrence‐free rate was higher in patients with durable LAAI following RF‐guided LAAI (RF:76.3% vs. CB:56.7%, p = .0017). Multivariate analysis revealed RF‐guided LAAI as a predictor of freedom from ATa recurrence (HR: 0.478, 95%CI: 0.336–0.823, p = .017). Conclusions LAAI can be more readily and safely achieved by CB‐guided ostial ablation. In patients with confirmed LAAI, however, the freedom from ATa recurrence was higher after RF‐guided wide‐area isolation.

Catheter ablation is a widely used, effective and safe treatment for AF. Pulsed field ablation (PFA), as a novel energy source for cardiac ablation, has been shown to be tissue selective and is expected to decrease damage to non-cardiac tissue while providing high efficacy in pulmonary vein isolation. The FARAPULSE ablation system (Boston Scientific) follows the idea of single-shot ablation and is the first device approved for clinical use in Europe. Since its approval, multiple high-volume centres have performed increasing numbers of PFA procedures in patients with AF and have published their experiences. This review summarises the current clinical experience regarding the use of PFA for AF using the FARAPULSE system. It provides an overview of its efficacy and safety.

Abstract The occurrence of disasters in deep mining engineering has been confirmed to be closely related to the external dynamic disturbances and geological discontinuities. Thus, a combined finite-element method was employed to simulate the failure process of an underground cavern, which provided insights into the failure mechanism of deep hard rock affected by factors such as the dynamic stress-wave amplitudes, disturbance direction, and dip angles of the structural plane. The crack-propagation process, stress-field distribution, displacement, velocity of failed rock, and failure zone around the circular cavern were analyzed to identify the dynamic response and failure properties of the underground structures. The simulation results indicate that the dynamic disturbance direction had less influence on the dynamic response for the constant in situ stress state, while the failure intensity and damage range around the cavern always exhibited a monotonically increasing trend with an increase in the dynamic load. The crack distribution around the circular cavern exhibited an asymmetric pattern, possibly owing to the stress-wave reflection behavior and attenuation effect along the propagation route. Geological discontinuities significantly affected the stability of nearby caverns subjected to dynamic disturbances, during which the failure intensity exhibited the pattern of an initial increase followed by a decrease with an increase in the dip angle of the structural plane. Additionally, the dynamic disturbance direction led to variations in the crack distribution for specific structural planes and stress states. These results indicate that the failure behavior should be the integrated response of the excavation unloading effect, geological conditions, and external dynamic disturbances.

The active forces exerted from the extracellular matrix (ECM) to mechanoreceptors have crucial impact on many cell functions and disease development. However, our understanding of the underlying mechanisms is held back due to the lack of ECM mimicking platform able to apply molecularly resolved forces to cells. Herein, we present novel hydrogel platform capable of generate pN range forces to specific cellular receptors, at molecular scale. This capability was achieved through near-infrared (NIR) light regulated macromolecular actuators functionalized within the platform. This platform enables us to reveal cell responses to molecularly resolved forces under controlled magnitude (150–400 ​pN) and frequency (up to 100 ​Hz) on matrix with varied stiffness. We find the stiffness of the matrix has a large influence on the applied force transduction to cells. This versatile platform holds the potential for establishing correlation between receptor signaling pathways and cellular responses closer to physiological conditions.

Abstract Solid electrolyte is a key component for all‐solid‐state lithium battery that is one of the most promising technologies for next‐generation energy storages. This review describes the challenges and strategies, preparation methods and outlook of oxide solid electrolytes for solid‐state lithium batteries. The general strategies on enhancing ionic conductivity of oxide solid electrolytes and reducing impedance interface are first summarized. We then introduce the basic structures of typical oxide electrolytes. The preparation technologies are also introduced for oxide electrolytes with various dimensions including bulk, thin film and fiber. In addition, the integration of oxide electrolytes with electrode materials is highlighted. In the last part, an outlook for the future development of oxide electrolytes towards practical applications is provided.

The chain drive system, being one of the core subsystems of the scraper conveyor, greatly influences the coal-conveying efficiency due to its dynamic characteristics. Therefore, this paper employed an experimental method to compare the dynamic characteristics of the chain rings at various positions within the chain drive system. This article simulated the three most common working conditions. The results indicated that the chain speed, load, and surface undulation had a stimulating effect on chain vibration, with the most significant impact observed on the chain ring located in the middle of the adjacent scraper. The scraper exerted an inhibitory effect on the vibration of the chain ring. Among the factors studied, the load had the most significant influence on the transverse direction. When there was surface undulation, the vibration of the chain ring in the running direction formed an ‘N’ shape. This condition intensified the vibration during uphill and downhill stages while suppressing vibration at the slope peak. This research holds great significance in enhancing operation stability.

The economic value of a mineral resource is highly dependent on the accuracy of grade estimations. Accurate predictions of mineral grades can help businesses decide whether to invest in a mining project and optimize mining operations to maximize the resource. Conventional methods of predicting gold resources are both costly and time-consuming. However, advances in machine learning and processing power are making it possible for mineral estimation to become more efficient and effective. This work introduces a novel approach for predicting the distribution of mineral grades within a deposit. The approach integrates machine learning and optimization techniques. Specifically, the authors propose an approach that integrates the random forest (RF) and k-nearest neighbor (kNN) algorithms with the marine predators optimization algorithm (MPA). The RFKNN_MPA approach uses log normalization to reduce the impact of extreme values and improve the accuracy of the machine learning models. Data segmentation and the MPA algorithm are used to create statistically equivalent subsets of the dataset for use in training and testing. Drill hole locations and rock types are used to create each model. The suggested technique’s performance indices are superior to the others, with a higher R-squared coefficient of 59.7%, a higher R-value of 77%, and lower MSE and RMSE values of 0.17 and 0.44, respectively. The RFKNN_MPA algorithm outperforms geostatistical and conventional machine-learning techniques for estimating mineral orebody grades. The introduced approach offers a novel solution to a problem with practical applications in the mining sector.

To investigate the deterioration laws of concrete durability under the coupling action of salt erosion and drying–wetting cycles, this study evaluated the macro–performance evolution of concrete under different environments (NaCl, Na2SO4, and MgSO4). Several measuring methods including nuclear magnetic resonance, computerized tomography tests, and microscopic morphology analysis are employed to investigate the damage mechanism of concrete. Experimental results show that with the action of salt erosion and drying–wetting cycles, the mass loss rate of concrete decreased first and then increased, and the relative dynamic modulus of elasticity and the compressive strength increased first and then decreased. The porosity and the pore quantity fluctuation increased. During the whole erosion process, needle-like attack products were formed in the pores, the crystals gradually filled the pores, and generated expansion pressure on the pore wall. As a result, concrete damage gradually occurred. Consequently, the damage degree was greater. The degrees of concrete damage under drying–wetting cycles induced were arranged as MgSO4>Na2SO4>NaCl.

The enhancement of the thermal conductivity can be utilized to reduce the temperature difference between the internal and external structural surfaces and thus the thermal induced stresses in concrete. This study investigated the compressive strength and thermal conductivity in concrete structures enhanced by the steel fiber and graphite at different volume fractions. First, the cubic and the cylinder concrete samples were fabricated by adding different volume fractions of the steel fibers, such as 0%, 0.5%, 1.0%, 1.5%, 2.0%, and 2.5%, to the concrete mixture. The fiber enhanced samples were tested following the standard procedures, and the optimal compressive strength and thermal conductivity can be obtained in the sample with the volume fraction of steel fiber at 1.5%. Moreover, graphite powders with different volume proportions at 5%, 10%, and 15% were added to the fiber enhanced concrete samples with identical size. The compressive strength and thermal conductivity tests were also performed and the optimal content of steel fiber was 1.5%, and the graphite was 5%. These results could not only meet the design requirements of the compressive strength of the concrete, but also improve the thermal conductivity of the concrete. The research could provide some reference for the design of the high thermal conductivity concrete.

Abstract The present work investigated the differences in the composition and internal microstructure of four types gypsum rock—fiber gypsum, transparent gypsum, alabaster, and ordinary gypsum by X-ray fluorescence spectrometry, X-ray diffraction, scanning electron microscope and Brazilian split test, and analyzed its effects on the tensile strength and fracture characteristics of gypsum rock. For alabaster, fiber gypsum, transparent gypsum, and ordinary gypsum, CaSO4·2H2O is the main component with 72.78%, 72.72%, 72.57%, and 71.51% content, and tensile strength of 1.79, 2.22, 3.22, and 4.35 MPa, respectively. In addition, the fracture line is arc-shaped, vertical, and zigzag for fiber gypsum, ordinary and transparent gypsums, and alabaster, respectively. On the microscopic level, fiber gypsum has an evident striated structure while the gradual increased pore development for alabaster, transparent gypsum, and ordinary gypsum. Gypsum rock has an obvious layered crystal structure with the increase of CaSO4·2H2O, contributing to the phenomenon with a larger grain size and lower tensile strength. In addition, the number of particles for alabaster, transparent gypsum, and ordinary gypsum increased in turn, while their particle size decreased uniformly, indicating that the lower CaSO4·2H2O content, the more sufficient energy accumulation and release. This paper can provide a theoretical basis for the analysis of the mechanical properties of rocks with different mineral composition and contribute to the design for different ore grades mining.

Abstract Algae contamination accumulated on the surface of insulators will affect the electrical properties of insulators. At present, the characterization method of algae contamination is the image method, which determines the distribution of algae contamination through colour. The detection results are affected by environmental changes and the growth state of algae. This paper puts forward a method of detecting polluted insulator surface with algae by using laser‐induced breakdown spectroscopy (LIBS) technique, combined with the scanning electron microscope (SEM), inductively coupled plasma emission spectrometer (ICP), analyzed by the spectra of algae contamination. Mg, Ca, Fe are selected as the analytical element. The classification of algae contamination, non‐algae contamination and no contamination are realized with the principal component analysis (PCA). The research results are of great significance for characterization of algal pollution on insulator surface by LIBS.

ObjectiveTo evaluate the efficacy and safety of lower ablation indexes (AI) guided pulmonary vein isolation (PVI) in treating paroxysmal atrial fibrillation (AF).MethodsNinety patients with paroxysmal AF scheduled for radiofrequency ablation were randomly divided into three groups. The AI targets for PVI were as follows: In group A/B/C, 550/500/450 for roof and anterior wall, and 400/350/300 for posterior/inferior wall. The first-pass PVI rate, ablation time, complications and recurrence of atrial tachyarrhythmia (ATa) were compared.ResultsThe mean age was 62.5 years (male: 63.0%), mean body mass index (BMI): 24.35 ± 3.66 kg/m2. The baseline characteristics were comparable. There was no significant difference in the first-pass PVI rate among the three groups (left-sided-PV: 66.7% vs. 80% vs. 73.3%, P = 0.51; right-sided-PV: 70% vs. 83.3% vs. 73.3%, P = 0.64), also with similar gap rate during the procedural waiting time. At 1-year follow-up there was no significant difference in the recurrence rate of ATa among the three groups (10% vs. 13.3% vs. 13.3%, P = 1.00). The ablation time in the Group C was significantly less than that in the other two groups (47.8 min. vs. 47.0 min. vs. 36.6 min, P < 0.001). Higher AI seemed to link a non-significant trend toward higher rate of pericardial effusion (group A + B vs. group C:6.7% vs. 0%, P = 0.30), although the rate of overall complications was not different among the three groups.ConclusionThis randomized study shows that, a relatively lower target AI guided ablation may be similarly effective to achieve PVI with significantly reduced ablation time and obtain similar clinical outcome in treating paroxysmal AF in Asian population.Clinical Trial Registration[www.ClinicalTrials.gov], identifier [NCT:04549714].

Domain generation algorithms (DGAs) play an important role in network attacks and can be mainly divided into two types: dictionary-based and character-based. Dictionary-based algorithmically generated domains (AGDs) are similar in composition to normal domains and are harder to detect. Although methods based on meaningful word segmentation and n-gram sequence features exhibit good detection performance for AGDs, they are inadequate for mining meaningful word features of domain names, and the performance of hybrid detection of character-based and dictionary-based AGDs needs to be further improved. Therefore, in this paper, we first describe the composition of dictionary-based AGDs using meaningful word segmentation, introduce the standard deviation to better measure the word distribution features, and construct additional 11-dimensional statistical features for word segmentation results as a supplement. Then, by combining 3-gram and 1-gram sequence features, we improve the detection performance for both character-based and dictionary-based AGDs. Finally, we perform feature fusion of the above four kinds of features to achieve an end-to-end detection method for both kinds of AGDs. Experimental results showed that our method achieved an accuracy of 97.24% on the full dataset and better accuracy and F1 values than existing methods on both dictionary-based and character-based AGD datasets.

PRKAG2 cardiomyopathy is a rare progressive disease characterized by increased ventricular wall thickness and preexcitation. Dysfunction of the protein 5′-AMP-activated protein kinase (AMPK) plays a decisive role in the progression of ventricular lesions. Although patients with the PRKAG2-R302Q mutation have a high incidence of atrial fibrillation (AF), the molecular mechanism contributing to the disease remains unclear. We carried out whole-genome sequencing with linkage analysis in three affected members of a family. Atrial samples were obtained from the proband via surgical intervention. Control atrium biopsies were obtained from patients with persistent AF. Pathological changes were analyzed using the hematoxylin and eosin (H&E), Masson, and periodic acid–Schiff (PAS) staining. The AMPK signaling pathway was investigated by western blot. A murine atrial cardiomyocyte cell line (HL-1) and human induced pluripotent stem derived atrial cardiomyocytes (hiPSC-ACMs) were transfected with an adenovirus carrying the same mutation. We used enzyme linked immunosorbent assay (ELISA) to determine the AMPK activity in HL-1 cells and hiPSC-ACMs overexpressing PRKAG2-R302Q. Pathological results showed a large quantity of glycogen accumulation and vacuolization in cardiomyocytes from the proband atrial tissue. Western blot analysis revealed that the AMPK activity was significantly downregulated compared with that of the controls. Furthermore, remarkable glycogen deposition and impairment of AMPK activity were reproduced in HL-1 cells overexpressing PRKAG2-R302Q. Taken together, PRKAG2-R302Q mutation directly impair atrial cardiomyocytes. PRKAG2-R302Q mutation lead to glycogen deposition and promote the growth of atrial lesions by disrupting the AMPK pathway.

In this paper, we performed uniaxial compression tests on fine sandstone–coal, coarse sandstone–coal, and oil shale–coal bi-material samples to investigate the lithology effects on their strength, macro-failure initiation (MFI), energy evolution, and failure characteristics, respectively. Uniaxial stress–strain characteristics of the samples primarily depended on the coal and were affected by coal–rock interactions. These interactions involved the following aspects: (1) The differences in the mechanical properties of rock and coal affected their stress states near the interface. They were in triaxial compression state with strength increasing or in triaxial compression-tension state with strength decreasing. (2) During the pre-peak stage, the rock deformation affected the values of input energy, elastic energy, and dissipated energy. Damage and energy accumulation in coal were also limited by rock deformation, resulting in higher strengths for the bi-material samples compared to pure coal samples. (3) During the post-peak stage, the rebound deformation of rock was accompanied by the elastic energy release, which promoted the failure of coal. MFI of the samples occurred within the coal. MFI models mainly included the tensile fracture of coal near the interface, the initiation and propagation of macro-cracks, and the development and evolution of micro-defects, accompanied by varying degrees of surface spalling or ejection failure. The coal showed the splitting ejection failure. The oil shale and coarse sandstone exhibited tensile failure or tensile–shear composite failure due to crack propagation in coal. Failure was not evident in the fine sandstone. The coal in the oil shale-coal bi-material samples became more broken due to the most serious rebound deformation of oil shale.

We present a case of ventricular fibrillation triggered by a premature ventricular complex. During ablation from the left coronary cusp, the ablation catheter dislodged inside left main coronary artery, thus resulting in cardiac arrest. We immediately performed angioplasty and stent implantation, and the procedure was accomplished with a guiding catheter left inside the vessel. (Level of Difficulty: Intermediate.)

Hypertension significantly increases the risk of cardiovascular events and it is associated with high rates of disability and mortality. Hypertension is a common cause of cardiovascular and cerebrovascular accidents, which severely affect patients’ quality of life and lifespan. Current treatment strategies for hypertension are based primarily on medication and lifestyle interventions. The renal sympathetic nervous system plays an important role in the pathogenesis of hypertension, and catheter-based renal denervation (RDN) has provided a new concept for the treatment of hypertension. In recent years, studies on RDN have been performed worldwide. This article reviews the latest preclinical research and clinical evidence for RDN.

Abstract Maze‐like linear substrate modification in atrial fibrillation patients nonresponders to pulmonary vein isolation represents a feasible technique to gain left atrial appendage electrical isolation even in the presence of a Watchman occluder device.

Abstract Energy storage in deep underground and mineral mining has currently become a hot research topic. To investigate the tensile failure of expansive soft rocks, a disk splitting mechanical model was established under a coupled action of the humidity and mechanical fields. Then, based on the theory of humidity stress field and the solution to the stress of a semi‐infinite body under the action of a concentrated force, an analytical formula for the stress of the disk under the action of the two fields was derived. Using the analytical formula, the influence of the humidity field and disk physical parameters on the distribution of the stress field on the disk under the coupled humidity‐mechanical action was further analyzed. Finally, the formula for the splitting tensile strength of expansive soft rocks under the influence of humidity was modified. The analysis results showed that the stress evolution of the disk under the coupled humidity‐mechanical action was completely different from that under a single‐load action. The stress concentration was generated at the dry‐wet interface of the disk. In addition, the range and value of the stress concentration zone increased with the increase in the humidity of the external environment, elastic modulus of soft rock, and linear expansion coefficient. Under the action of a single load, the cracking position was at the center of the disk. In contrast, under the coupled humidity‐mechanical action, the cracking position was transferred to the intersection of the dry‐wet interface and the loading direction. The above results can provide preliminary theoretical guidance for understanding the tensile failure mechanism of expansive soft rocks.

Fish oil is rich in unsaturated fatty acids, i.e., eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), both of which are widely distributed in the body such as heart and brain. In vivo and in vitro experiments showed that unsaturated fatty acids may have effects of anti-inflammation, anti-oxidation, protecting vascular endothelial cells, thrombosis inhibition, modifying autonomic nerve function, improving left ventricular remodeling, and regulating blood lipid. Given the relevance to public health, there has been increasing interest in the research of potential cardioprotective effects of fish oil. Accumulated evidence showed that fish oil supplementation may reduce the risk of cardiovascular events, and, in specific, it may have potential benefits in improving the prognosis of patients with hypertension, coronary heart disease, cardiac arrhythmias, or heart failure; however, some studies yielded inconsistent results. In this article, we performed an updated systematical review in order to provide a contemporary understanding with regard to the effects of fish oil on cardiovascular diseases.

Abstract The treatment of flue‐gas desulfurization (FGD) gypsum, a common solid waste material that is often affected by chloride ions, typically occupies large amounts of land, causes resource waste, and results in environmental pollution. An emission reduction process involving the dechlorination of FGD gypsum and reducing its emissions has been proposed to solve these problems. Laboratory experiments were conducted to verify the feasibility of the emission reduction process and study any differences from the conventional process. The test results indicated that the average dechlorination rate of the emission reduction process was 80.4%, which is equivalent to 97.5% of the conventional process. The average dechlorination wastewater volume of the emission reduction process was 0.22 L, which is equivalent to 4.9% of the conventional process. The results show that the emission reduction process can effectively reduce the chlorine content of FGD gypsum and its related wastewater discharge. This novel gypsum dechlorination process effectively reduces the chlorine content of FGD gypsum and related wastewater. In addition, the emission reduction process can lead to greater recovery of renewable resources and can result in a cleaner energy conversion process. This process is an alternative method for recovering residues and resources without secondary pollution. Therefore, if this technology is integrated into existing FGD facilities, costly chemical processes could be replaced by those that recover a renewable resource and incorporate a clean energy conversion process.

Abstract Bolt is an important connection in underground construction and monitoring its stress characteristics is essential to evaluate the effectiveness of bolt. The strain information collected along a rock bolt reveals the long‐term movement characteristics of rock mass, which greatly helps toward disaster prevention and risk warning. Grooving on the surface of a bolt and embedding an optical fiber is one of the main methods for monitoring the anchorage performance and stress distribution around the bolt in underground engineering. In this study, Pulse Pre‐Pumped Brillouin Optical Time Domain Analysis (PPP‐BOTDA) technology is used to evaluate the stress, axial force, and shear stress distribution of the bolt under tensile load for different types (grooved and nongrooved) of bolts embedded in concrete with resin as anchoring agent. The results show that the PPP‐BOTDA sensor can be used to monitor the stress state of the bolt embedded in concrete with resin as anchoring agent when the bolt is subjected to a tensile force. However, the apparent stress value measured in this way is not the actual stress value of the bolt, but is an increased value caused due to the groove. The closer to the exposed end of the bolt, the greater is the deviation between the apparent stress value and the actual stress value of the bolt. Based on the monitoring results from this experimental study, a stress reduction calculation method is proposed, which can change the measured value into the actual stress of the bolt.

Abstract Background We previously reported an inverse relationship between B cell-specific Moloney murine leukemia virus integration site 1 (Bmi-1) and Raf kinase inhibitory protein (RKIP), which is associated with the prognosis of gastric cancer (GC). In this study, we further explored the microRNA (miRNA) regulatory mechanism between Bmi-1 and RKIP. Methods Microarray analysis was first carried out to identify miRNA profiles that were differentially expressed in cells overexpressing Bmi-1. Then, miRNAs that could regulate RKIP were identified. Quantitative real-time PCR (qRT-PCR) and Western blotting were performed to measure the expression of Bmi-1, miR-155, miR-27a and RKIP. RKIP was confirmed as a target of miR-27a and miR-155 through luciferase reporter assays, qRT-PCR and Western blotting. The effects of the Bmi-1/miR-27a/RKIP and Bmi-1/miR-155/RKIP axes on tumor growth, proliferation, migration, invasion, colony-formation ability, metastasis and chemoresistance were investigated both in vitro and in vivo. Results The downregulation of RKIP by Bmi-1 occurred at the protein but not mRNA level. This indicates probable posttranscriptional regulation. miRNA expression profiles of cells with ectopic expression of Bmi-1 were analyzed and compared to those of control cells by microarray analysis. A total of 51 upregulated and 72 downregulated miRNAs were identified. Based on publicly available algorithms, miR-27a and miR-155 were predicted, selected and demonstrated to target RKIP. Bmi-1, miR-27a and miR-155 are elevated in human GC and associated with poor prognosis of GC, while RKIP is expressed at lower levels in GC and correlated with good prognosis. Then, in vitro tests shown that in addition to regulating RKIP expression via miR-27a and miR-155, Bmi-1 was also able to regulate the migration, invasion, proliferation, colony-formation ability and chemosensitivity of GC cells through the same pathway. Finally, the in vivo test showed similar results, whereby the knockdown of the Bmi-1 gene led to the inhibition of tumor growth, metastasis and chemoresistance through miR-27a and miR-155. Conclusions Bmi-1 was proven to induce the expression of miR-27a and miR-155 and thus promote tumor metastasis and chemoresistance by targeting RKIP in GC. Overall, miR-27a and miR-155 might be promising targets for the screening, diagnosis, prognosis, treatment and disease monitoring of GC.

Abstract Purpose The diagnostic value of nomogram in pancreatic cancer (PC) with liver metastasis (PCLM) is still largely unknown. We sought to develop and validate a novel nomogram for the prediction of liver metastasis in patients with PC. Method About 604 pathologically confirmed PC patients from the Sun Yat‐sen University Cancer Center (SYSUCC) between July, 2001 and December, 2013 were retrospectively studied. The SYSUCC cohort was randomly assigned to as the training set and internal validation set. Using these two sets, we derived and validated a prognostic model by using concordance index and calibration curves. Another two independent cohorts between August, 2002 and December, 2013 from the Sun Yat‐sen Memorial Hospital (SYSMH, n = 335) and Guangdong General Hospital (GDGH, n = 503) was used for external validation. Result Computed tomography (CT) reported liver metastasis status, carcinoembryonic antigen (CEA) level and differentiation type were identified as risk factors for PCLM in the training set. The final diagnostic model demonstrated good calibration and discrimination with a concordance index of 0.97 and had a robust internal validation. The score ability to diagnose PCLM was further externally validated in SYSMH and GDGH with a concordance index of 0.93. The model showed better calibration and discrimination than CT, CEA and differentiation in each cohort. Conclusion Based on a large multi‐institution database and on the routinely observed CT‐reported status, CEA level and tumor differentiation in clinical practice, we developed and validated a novel nomogram to predict PLCM.

Abstract Most of the surrounding rocks of offshore liquefied petroleum gas (LPG) reservoirs occur in jointed rock mass. This paper is aimed at the reinforcement of the layered composite rock masses. First, the structural mechanical model of the elastic deformation and completely plastic deformation for the bolt was constructed. Then, the equations of axial force, shear force, and bending moment in the cross section of the bolt were obtained by the force‐method canonical equation. The shear‐slip resistance effect of the bolt was decomposed into the friction effect and the dowel effect. In addition, the quantitative relationship between shear resistance and the characteristic angles (anchoring angle, friction angle, dilatancy angle, and deflection angle) and the geometrical and physical parameters of the bolt were derived. Finally, the influence of each characteristic angle on the mechanical properties of the bolt was analyzed in details and the model was verified. The analysis results showed that the laterally constrained load of the rock stratum on the bolt can be characterized by a power function, but the optimal power should be no less than 10. The dominant position of either the friction effect or the dowel effect was changed with the matching of different characteristic angles. The increase of the friction angle and dilatancy angle of the joint surface of the rock is beneficial to improve the lateral shear resistance of the bolt. The effect of the deflection angle on the lateral shear resistance of the bolt was affected by the anchoring angle. The optimal anchoring angle of the bolt should be in the range of 50°‐60°. The results in this study have important theoretical significance to guide the offshore anchoring engineering of layered composite rock masses.

Abstract Cryogenic nitrogen fracturing is an attractive method for stimulating underground reservoir, since it could favorably induce complex fracture due to the huge temperature difference with lower injection pressure and with the replacement of current water‐based fracturing fluid. However, the concern about whether cryogenic nitrogen would be overheated remains unrevealed in the engineering environment with large wellbore length. In addition, reservoir stimulation results are also related with the pressure state at bottom hole. Therefore, in this study, a mathematical model was proposed to predict the radial heat transfer and its influence on vertical pressure transmission in the wellbore with cryogenic nitrogen as fracturing fluid. The model fully couples the heat transfer, hydraulics, and the compressibility of nitrogen, and then, the calculation results were presented and analyzed through a case study. According to the results, the temperature of nitrogen increases too fast under conventional engineering conditions, and it changes into gaseous state at the depth lower than 100 m. Finally, the temperature difference between nitrogen and formation rock becomes too minimal to induce thermal stress at bottom hole. Due to the fast temperature increase, the density of nitrogen decreases too much, and the vertical pressure increasing rate by liquid nitrogen (1.66 MPa/km) is merely 18.2% that in carbon dioxide fracturing (9.13 MPa/km). The results indicate that utilization of special casing with much larger thermal resistance is an indispensable approach to realize the feasibility and advantages of cryogenic nitrogen fracturing.

Abstract Slabbing failure and strain rock burst are the main failure patterns during the excavation and construction phases of deep tunnels in hard and brittle rock, which cause unexpected equipment damage and casualties. This study presents a numerical simulation with an unloading central hole within a hard rock specimen in the laboratory scale. A combined finite element/discrete element method (FEM/DEM) reproduces the crack initiation, propagation, and coalescence around the central hole during the entire failure process. The influence of sectional shapes, unloading rates of holes, and in situ stresses on the failure characteristics and mechanical response of typical hard and brittle rocks were investigated by analysis of the failure pattern, displacement distribution (average velocity) of monitoring elements, and released strain energy value. The numerical results indicate that the sectional shapes, unloading rates, and in situ stresses have a significant impact on the severity of destruction and failure range in hard rock under the excavation unloading conditions. Slabbing failure (stable failure) is always the dominant failure pattern around a circular hole, which shows higher bearing capacities and self‐stabilization. With the increase in unloading rates, more visible cracks are generated around the holes, and the displacement and average velocity of discrete blocks are further raised. This is particularly evident in rock specimens with holes having vertical walls, leading to intense unstable failure (strain rock burst) accompanied by a large amount of strain energy released. In situ stresses affect considerably the stability of the surrounding rock during the excavation unloading process. With constant in situ stress, the order of destruction severity around the central hole according to its sectional shape is cube > trapezoid > U‐shape > ellipse > circle. The destruction intensity is further aggravated with the increase in lateral pressure coefficient, and the failure regions are always observed in the roof and floor of the central hole. This study confirms that strain rock burst tends to be induced in hard and brittle rock tunnels with polygonal roadway section under high unloading rates and lateral pressure coefficients.

Abstract Water‐coal interactions have gained much recent attention, although few studies focus on the strength of coal under wetting‐drying cycles. This study investigates changes in the microstructure and mechanical strength of coal that are induced by water‐coal interactions, at the macroscale and microscale. Fourteen specimens after continuous wetting and fourteen specimens after wetting‐drying cycles were tested, indicating that peak stress and elastic modulus decrease with increasing continuous wetting time and number of wetting‐drying cycles, while peak strain increases. We analyzed changes in the coal microstructure using a scanning electron microscope (SEM) and the Image Pro Plus 6.0 (IPP 6.0) software. The regression model for cyclic wetting‐drying reveals that porosity and pore circularity are the main correlation indicators associated with uniaxial compressive strength. Therefore, different numbers of wetting‐drying cycles could induce different degrees of damage to coal, which increases progressively through gradual changes to its microstructure. These findings indicate that wetting‐drying cycles have a more significant impact on the stability of coal mass than continuous wetting. Our results are of use in determining the size of coal pillars, and expanding the knowledge base related to the mechanical properties of coal mass, water bursting, water recharge channels, and the stress‐crack‐permeability evolution law in mines.

Abstract Hard rock failure and rockburst hazards under high in situ stresses have been the subject of deep rock mechanics and engineering. Previous investigations employed cubic rock specimens with a central hole for simulation of rock fracturing around deep tunnels at a laboratory scale, while the failure characteristics and crack evolution behavior around different shapes of holes induced by excavation unloading response have been barely considered. A commercially combined finite‐discrete element method (combined FEM/DEM) was used to investigate the failure characteristics and crack propagation process of typical hard rock specimens (marble) via the unloading of central hole with different shapes. Rock heterogeneity was also considered in the model in combination with the engineering reality. The combined FEM/DEM approach was first validated by simulating uniaxial compression and Brazilian tests. Then, the parametrical analysis was conducted in detail on the basis of five different sectional shapes of central holes, including a circle, ellipse, U‐shape, trapezoid, and cube, and two lateral pressure coefficients. Analysis of crack propagation paths, released strain energy, displacement, and average velocity distribution of the monitoring points around the central hole suggests that the failure degree and destruction intensity are strongly related to the sectional shape and lateral pressure coefficients. Hard and brittle rock failure induced by the excavation unloading effect can be classified as stable failure (slabbing failure) and unstable failure (strain rockburst). The cubic, trapezoidal, and U‐shaped holes within the specimen are the most likely to induce unstable failure, while stable failure is the dominant failure pattern around circular and elliptical holes. The lateral pressure coefficient λ was also found to affect failure position and intensity (only for the axisymmetric section) around the central hole. The influence of rock heterogeneity on failure intensity and range around the central hole within the specimen was also discussed. This study emphasizes the importance and necessity of the excavation unloading effect when evaluating surrounding rock failure around deep tunnels.

Abstract Background Cryoballoon ablation is an established procedure for atrial fibrillation (AF). Patients who had previous pulmonary surgery undergoing pulmonary vein isolation (PVI) were seldom reported. Case presentation We describe an AF ablation using the novel short-tip third-generation cryoballoon in a patient with resected pulmonary vein. All pulmonary veins were successfully isolated without complication. The short-tip third-generation cryoballoon shows advantageous profile in PVI for AF patients with previous pulmonary surgery. Conclusions This report indicates that for AF patient who had previous resected PV surgery, the short-tip CB 3 provides an ideal device option for real-time PVI.