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Double-arch tunnels, as one of the popular forms of tunnels, might be exposed to boiling liquid expanding vapour explosions (BLEVEs) associated with transported liquified petroleum gas (LPG), which could cause damage to the tunnel and even catastrophic collapse of the tunnel in extreme cases. However, very limited study has investigated the performance of double-arch tunnels when exposed to internal BLEVEs and in most analyses of tunnel responses to accidental explosions. The TNT-equivalence method was used to approximate the explosion load, which may lead to inaccurate tunnel response predictions. This study numerically investigates the response of typical double-arch tunnels to an internal BLEVE resulting from the instantaneous rupture of a 20 m3 LPG tank. Effects of various factors, including in-situ stresses, BLEVE locations, and lining configurations on tunnel responses are examined. The results show that the double-arch tunnels at their early-operation ages are more vulnerable to severe damage when exposed to the BLEVE due to the low action of in-situ stress of rock mass on the response of early-age tunnels. It is also found that directing the LPG tank to different driving lanes inside tunnels can affect the BLEVE-induced tunnel response more significantly than varying the configurations of tunnel lining. Moreover, installing section-steel arches in the mid-wall can effectively improve the blast resistance of the double-arch tunnels against the internal BLEVE. In addition, the prediction models based on multi-variate nonlinear regressions and machine learning methods are developed to predict the BLEVE-induced damage levels of the double-arch tunnels without and with section-steel arches.

Iron tailing porous concrete (ITPC) is a new type of green-engineered composite that uses iron ore tailing (IOT) powder to partially replace cement in conventional foamed concrete. This study investigates the dynamic properties of ITPC with a range of IOT content (15 % to 35 %) under high-strain rate loads, as well as the hydration products and microstructures of ITPC. Additionally, foamed concrete specimens without IOT powder are prepared and tested as references. The X-ray diffraction (XRD) results indicate that the addition of IOT powder causes the presence of iron oxide (Fe2O3) and silicon dioxide (SiO2) in the ITPC, resulting in a decrease in calcium silicate hydrate (C-S-H) gel and ettringite (AFt). A split Hopkinson pressure bar (SHPB) facility is used to perform impact tests at expected strain rates from 120 to 250 s−1. The experimental results demonstrate that the properties of ITPC obtained in dynamic loading tests exhibit significant IOT content dependence and strain rate effects. Moreover, scanning electron microscopy (SEM) analysis reveals that excessive IOT content results in the formation of numerous micro-cracks and loose pore structures within the ITPC specimens. ITPC with IOT content ranging from 25 % to 30 % achieves the optimal performance with high impact resistance and effective utilization of iron tailing waste. Specifically, at the expected strain rates of 120, 200, and 250 s−1, increasing the IOT content from 15 % to 35 % resulted in reductions of compressive strength by 37.52 %, 51.34 %, and 51.22 %, respectively. The corresponding dynamic increase factors of ITPC achieved the maximum values of 1.25 (25 % IOT content), 2.16 (30 % IOT content) and 3.12 (30 % IOT content), respectively.

Liquid–liquid separation, commonly referred to as oiling-out, frequently can occurs during crystallization, especially the anti-solvent crystallization process of phosphoryl compounds, and poses potential hurdle for high-quality product. Efficiently regulating oiling-out during crystallization remains a significant challenge. Among various techniques, ultrasound emerges as a green and effective approach to enhance the crystallization process. However, there is a dearth of in-depth research exploring the microscopic mechanisms of this process. Therefore, our research focused on the fructose-1,6-diphosphate (FDP), a typical phosphoryl compound, to gain a deeper understanding of how ultrasound influences the oiling-out process. The focused beam reflectance measurement (FBRM) technology was used to investigate the oiling-out phenomenon of FDPNa3 across various solvent ratios. In addition, the influence of ultrasound on the induction time was studied and the nucleation energy barrier was calculated. Finally, to further unravel the microscopic mechanisms, we utilized molecular simulation techniques to analyze the impact of ultrasound power on the dissolution-precipitation process. Our observations revealed a consistent oiling-out process that attainted a stable state regardless of the solvent employed. Notably, the results of the oiling-out induction time experiments indicated that ultrasound significantly reduced helped lower the nucleation energy barrier of FDP3- ions, thereby dismantling FDP3-clusters in solution. Thus, in turn, shortened the reduced induction time and promoted crystallization. Furthermore, ultrasound reduced the interactions between FDP3-ions and water molecules as well as FDP3- ions themselves. As simulated field intensity increased, these interaction forces gradually diminished, the thickness of the hydration layer surrounding the FDP3- clusters facilitating the disruption of clusters, ultimately enhancing the crystallization process.

Iron tailing porous concrete (ITPC) is a new foamed concrete material that using iron ore tailing powder to partially replace the cement. Previous investigations on ITPC primarily focused on its mechanical properties under static loads or low strain rate conditions, leaving a significant gap in its impact resistance performance at high strain rates. This study employed the split Hopkinson pressure bar (SHPB) to test ITPC specimens under impact loading with strain rate around 120 s−1. Density, water-binder (W/B) ratio, iron tailing powder content, polypropylene fiber length and content were taken as key design variables to prepare the ITPC specimens with different mix ratios and study their effects on the dynamic material properties of ITPC. Specifically, the failure modes, stress-strain relations, elastic moduli, compressive strengths and energy dissipation densities of the ITPC specimens with various design variables were recorded and compared. The test results indicate that the material density, fiber length and content have strong influences on the impact failure modes of ITPC. The elastic modulus, compressive strength and energy dissipation density of ITPC exhibit exponential growth with the material density. These parameters, however, show an initial growth followed by a decrease with the rising W/B ratio, fiber length and fiber content, and they reach the peak values at around 0.70, 9 mm and 2.0%, respectively. Moreover, the iron tailing powder content of 25% is recommended for ITPC for maintaining good impact resistance.

Accidental boiling liquid expansion vapour explosions (BLEVEs) caused by the bursting of liquified petroleum gas (LPG) tank inside a tunnel can induce vibrations of its surrounding geological media and threaten the stability of adjacent tunnels and structures. Therefore, it is essential to understand the characteristics of vibrations induced by LPG BLEVEs inside the tunnel for the safety design of its adjacent structures. Owing to the difficulty in effectively predicting the LPG BLEVE loads, the current practice usually employs equivalent methods, e.g., the TNT-equivalency method, in LPG BLEVE load predictions for structural response analysis, which may lead to inaccurate response predictions. This study compares ground vibrations induced by a BLEVE inside an arched road tunnel with those induced by its equivalent TNT explosion via high-fidelity numerical simulations. The results demonstrate that the frequency of BLEVE-induced vibrations is lower than that induced by the TNT explosion at the same scaled distance. The intensity of LPG BLEVE-induced vibrations at relatively small-scaled distances is lower than that of TNT explosion-induced vibrations at the same scaled distance, but becomes higher after a certain scaled distance because of the relatively low attenuation rate. In addition, parametric analysis is conducted to evaluate the effects of various factors on the characteristics of LPG BLEVE-induced ground vibrations. It is found that the surrounding rock type, the rock porosity, and the cover depth of the tunnel have more significant influences than the concrete grade of the tunnel lining. The recommendation for the tunnel design is also given based on the intensity and frequency characteristics of BLEVE-induced vibrations.

Background: Launched in March 2019, the National Centralized Drug Procurement (NCDP) initiative aimed to optimize the drug utilization framework in public healthcare facilities. Following the integration of Non-Vitamin K Antagonist Oral Anticoagulants (NOACs) into the procurement catalog, healthcare establishments in Suining swiftly transitioned to the widespread adoption of NOACs, beginning 1 March 2020.Objective: This study aims to comprehensively assess the impact of the NCDP policy on the efficacy of anticoagulation therapy, patient medication adherence, and the incidence of hemorrhagic events in individuals with non-valvular atrial fibrillation (NVAF) residing in Suining. The analysis seeks to elucidate the broader impacts of the NCDP policy on this patient demographic.Methods: This study analyzed patient hospitalization records from the Department of Cardiology at Suining County People’s Hospital, spanning 1 January 2017, to 30 June 2022. The dataset included demographic details (age, sex), type of health insurance, year of admission, hospitalization expenses, and comprehensive information on anticoagulant therapy utilization. The CHA2DS2-VASc scoring system, an established risk assessment tool, was used to evaluate stroke risk in NVAF patients. Patients with a CHA2DS2-VASc score of 2 or higher were categorized as high-risk, while those with scores below 2 were considered medium or low-risk.Results: 1. Treatment Cost Analysis: The study included 3,986 patients diagnosed with NVAF. Following the implementation of the NCDP policy, a significant increase in the average treatment cost for hospitalized patients was observed, rising from 8,900.57 ± 9,023.02 CNY to 9,829.99 ± 10,886.87 CNY (p < 0.001). 2. Oral Anticoagulant Utilization: Overall, oral anticoagulant use increased from 40.02% to 61.33% post-NCDP (p < 0.001). Specifically, NOAC utilization among patients dramatically rose from 15.41% to 90.99% (p < 0.001). 3. Hemorrhagic Events: There was a significant decrease in hemorrhagic events following the NCDP policy, from 1.88% to 0.66% (p = 0.01). Hypertension [OR = 1.979, 95% CI (1.132, 3.462), p = 0.017], history of stroke [OR = 1.375, 95% CI (1.023, 1.847), p = 0.035], age ≥65 years [OR = 0.339, 95% CI (0.188, 0.612), p < 0.001], combination therapy of anticoagulants and antiplatelets [OR = 3.620, 95% CI (1.752, 7.480), p < 0.001], hepatic and renal insufficiency [OR = 4.294, 95% CI (2.28, 8.084), p < 0.001], and the NCDP policy [OR = 0.295, 95% CI (0.115, 0.753), p = 0.011] are significant risk factors for bleeding in patients with atrial fibrillation. 4. Re-hospitalization and Anticoagulant Use: Among the 219 patients requiring re-hospitalization, there was a notable increase in anticoagulant usage post-NCDP, from 36.07% to 59.82% (p < 0.001). NOACs, in particular, saw a substantial rise in usage among these patients, from 11.39% to 80.92% (p < 0.001). 5. Anticoagulant Type Change: The NCDP policy [OR = 28.223, 95% CI (13.148, 60.585), p < 0.001] and bleeding events [OR = 27.772, 95% CI (3.213, 240.026), p = 0.003] were significant factors influencing the alteration of anticoagulant medications in patients.Conclusion: The NCDP policy has markedly improved anticoagulation management in patients with AF. This policy has played a crucial role in enhancing medication adherence and significantly reducing the incidence of hemorrhagic events among these patients. Additionally, the NCDP policy has proven to be a key factor in guiding the selection and modification of anticoagulant therapies in the AF patient population.

Background: Cardiac magnetic resonance (CMR) imaging with gadolinium-based contrast agents offers unique non-invasive insights into cardiac tissue composition. Myocardial extracellular volume (ECV) has evolved as an objective and robust parameter with broad diagnostic and prognostic implications. For the gadolinium compound gadobutrol, the recommended dose for cardiac imaging, including ECV measurements, is 0.1 mmol/kg (single dose). This dose was optimized for late enhancement imaging, a measure of focal fibrosis. Whether a lower dose is sufficient for ECV measurements is unknown. We aim to evaluate the accuracy of ECV measurements using a half dose of 0.05 mmol/kg gadobutrol compared to the standard single dose of 0.1 mmol/kg. Methods and results: From a contemporary trial (NCT04747366, registered 10 February 2021), a total of 25 examinations with available T1 mapping before and after 0.05 and 0.1 mmol/kg gadobutrol were analyzed. ECV values were calculated automatically from pre- and post-contrast T1 relaxation times. T1 and ECV Measurements were performed in the midventricular septum. ECV values after 0.05 and 0.1 mmol/kg gadobutrol were correlated (R2 = 0.920, p < 0.001). ECV values after 0.05 mmol/kg had a bias of +0.9% (95%-CI [0.4; 1.4], p = 0.002) compared to 0.1 mmol/kg gadobutrol, with limits of agreement from −1.5 to 3.3%. Conclusions: CMR with a half dose of 0.05 mmol/kg gadobutrol overestimated ECV by 0.9% compared with a full dose of 0.1 mmol/kg, necessitating adjustment of normal values when using half-dose ECV imaging.

Abstract Background Thromboembolic events are the most serious complication of atrial fibrillation (AF), and the left atrial appendage (LAA) is the most important site of thrombosis in patients with AF. During the period of COVID-19, a non-invasive left atrial appendage detection method is particularly important in order to reduce the exposure of the virus. This study used CT three-dimensional reconstruction methods to explore the relationship between LAA morphology, LAA orifice area and its mechanical function in patients with non-valvular atrial fibrillation (NVAF). Methods A total of 81 consecutive patients with NVAF (36 cases of paroxysmal atrial fibrillation and 45 cases of persistent atrial fibrillation) who were planned to undergo catheter radiofrequency ablation were enrolled. All patients were examined by transthoracic echocardiography (TTE), TEE, and computed tomography angiography (CTA) before surgery. The LAA orifice area was obtained according to the images of CTA. According to the left atrial appendage morphology, it was divided into chicken wing type and non-chicken wing type. At the same time, TEE was performed to determine left atrial appendage flow velocity (LAAFV), and the relationship between the left atrial appendage orifice area and LAAFV was analyzed. Results The LAAFV in Non-chicken wing group was lower than that in Chicken wing group (36.2 ± 15.0 cm/s vs. 49.1 ± 22.0 cm/s, p-value

ObjectiveEpicardial adipose tissue (EAT) is related to atrial fibrillation (AF), but the specific mechanism is still unclear. Left atrial (LA) low voltage zones (LVZ) can well reflect atrial fibrosis. This study investigated the relationship between EAT and LVZ in non-valvular AF (NVAF) patients.MethodsThis observational study including patients with NVAF (n = 214) undergoing radiofrequency ablation (RFCA) for the first time in our hospital and 62 matched controls. The EAT volume and attenuation were measured by contrast-enhanced computed tomography. A three-dimensional mapping system was used to map the left atrial endocardium and evaluate LA-LVZ. Patients were divided into LVZ and non-LVZ groups according to the presence or absence of LVZ.ResultsPatients with AF showed higher LA-EAT volume and lower attenuation value than controls (29.7 ± 11.2 cm3 vs. 20.9 ± 8.6 cm3, P = 0.021; −91.2 ± 5.6 HU vs. −88.7 ± 5.9 HU, P < 0.001). Compared with the group without LVZ, there were significant differences in age [65 (59–71) vs. 60 (52–69), P = 0.006], LAVI [75.1 ± 20.7 ml/m2 vs. 67.2 ± 20.9 ml/m2, P = 0.018], LA-EAT volume (34.8 ± 11.5 cm3 vs. 28.1 ± 10.6 cm3, P < 0.001) and LA-EAT attenuation (−93.9 ± 5.3 HU vs. −90.4 ± 5.5 HU, P < 0.001). Multivariate regression analysis showed that age (OR = 1.040; 95%CI: 1.001–1.078, P = 0.042), LAVI (OR = 1.019; 95%CI: 1.002–1.037, P = 0.032), LA-EAT volume (OR = 1.193; 95%CI: 1.015–1.402, P = 0.034) and attenuation value (OR = 0.801; 95%CI: 0.701–0.916 P = 0.001) were independent predictors of LVZ. After LA-EAT attenuation was incorporated into the clinical model, the comprehensive discrimination and net reclassification tended to improve (IDI and NRI > 0, P < 0.05).ConclusionLA-EAT volume and attenuation values can independently predict the presence of LVZ, and LA-EAT attenuation has a better predictive value than LA-EAT volume.

Automatic and accurate onset time picking of the acoustic emission (AE) signals is of great significance for the location of acoustic events. However, the onset times are difficult to be picked accurately due to the presence of noise in signal records. To overcome this problem, an improved method including three consecutive processes is proposed in this study. First, the windowing Lempel-Ziv (WLZ) complexity method is applied to determine an approximate onset time. Then, the time series selected from the start time to the vicinity of the approximate onset time is coarsened at different scales with the application of multi-scale (MS) theory. Finally, Akaike information criterion (AIC) method is utilized to pick up the accurate onset time. Feasibility and performance of the proposed improved method are tested and compared with the other automatic onset time picking methods, such as AIC, short and long time average ratio (STA/LTA), modified energy ratio (MER), AIC with low pass filter and STA/LTA with low pass filter, using the same broken load experiment and 100 rock fracture signals with various signal-to-noise ratios (SNRs). The results show that the accuracy of automatic picks provided by the improved method are far beyond the other methods mentioned. Meanwhile, both the accuracy stability and SNR adaptability of the improved method for rock fracture signals are better than other methods, which proves that the improved method has the excellent performance to pick up onset times of AE signals.

Dysfunction of human endothelial cells is an important trigger for atherosclerosis. Oxidative low-density lipoprotein (ox-LDL) usually was used to stimulate the dysfunction of human umbilical vein endothelial cells (HUVECs). LncRNA SNHG1 (small nucleolar RNA host gene 1) is a cerebral infarction-associated gene. The present study was designed to investigate the role of SNHG1 in ox-LDL-induced HUVECs. Cell viability was evaluated by CCK-8 and MTT assay. Cell apoptosis was detected by flow cytometry analysis. Cell inflammatory response was evaluated by detecting LDH, IL-6, IL-1β levels. The results revealed that up-regulation of SNHG1 attenuated ox-LDL-induced cell injury and inflammatory response in HUVECs. Next, mechanism assays including RNA immunoprecipitation (RIP) assay, luciferase reporter assay, and RNA pull-down assay, helped us to identify the interaction between miR-556-5 and SNHG1. GNAI2 (G protein subunit alpha i2) and PCBP1 (poly(rC) binding protein 1) were identified as the downstream targets of miR-556-5p. SNHG1 regulated dysfunctions of ox-LDL-induced HUVECs via sponging miR-556-5p and up-regulating GNAI2 and PCBP1. SNHG1 attenuated cell injury and inflammatory response in ox-LDL-induced HUVECs via up-regulating both GNAI2 and PCBP1 at a miR-556-5p dependent way.

Closed-cell and open-cell hollow spheres were designed to develop lightweight cellular structures with excellent blast resistance, and the mechanical response of the hollow sphere structure (HSS) under blast loading was investigated numerically using ANSYS®/LS-DYNA®17.0. In this paper, the blast wave pressure decay rate was served as the main index of blast resistance while areal specific energy absorption and frame deformation were used as auxiliary indexes. The results indicated that the weight of HSS was reduced by 37.7%–69.8% compared to solid structures with the same physical size, and the blast resistance of HSS was significantly affected by the hollow sphere diameter and wall thickness, frame length and width, opening size and opening density. Closed-cell HSS with smaller hollow sphere diameters and thicker wall, or smaller frame lengths and widths would achieve the optimal blast resistance. Meanwhile, the blast resistance of HSS could be improved by adopting a smaller opening size, but the effect of opening density did not follow any rule, which was affected by the number and position of openings. Comprehensively, the blast resistance of HSS was enhanced when there was opening only at the face blast surface rather than at both the face blast surface and back blast surface. Keywords: Closed-cell hollow sphere, Open-cell hollow sphere, Blast resistance, Parametric design, Numerical simulation