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Amphibian skin is acknowledged to contain an antioxidant system composed of various gene-encoded antioxidant peptides, which exert significant effects on host defense. Nevertheless, recognition of such peptides is in its infancy so far. Here, we reported the antioxidant properties and underlying mechanism of a new antioxidant peptide, brevinin-1FL, identified from Fejervarya limnocharis frog skin. The cDNA sequence encoding brevinin-1FL was successfully cloned from the total cDNA of F. limnocharis and showed to contain 222 bp. The deduced mature peptide sequence of brevinin-1FL was FWERCSRWLLN. Functional analysis revealed that brevinin-1FL could concentration-dependently scavenge ABTS+, DPPH, NO, and hydroxyl radicals and alleviate iron oxidation. Besides, brevinin-1FL was found to show neuroprotective activity by reducing contents of MDA and ROS plus mitochondrial membrane potential, increasing endogenous antioxidant enzyme activity, and suppressing H2O2-induced death, apoptosis, and cycle arrest in PC12 cells which were associated with its regulation of AKT/MAPK/NF-κB signal pathways. Moreover, brevinin-1FL relieved paw edema, decreased the levels of TNF-α, IL-1β, IL-6, MPO, and malondialdehyde (MDA), and restored catalase (CAT) and superoxide dismutase (SOD) activity plus glutathione (GSH) contents in the mouse injected by carrageenan. Together, these findings indicate that brevinin-1FL as an antioxidant has potent therapeutic potential for the diseases induced by oxidative damage. Meanwhile, this study will help us further comprehend the biological functions of amphibian skin and the mechanism by which antioxidants protect cells from oxidative stress.

The Hoek-Brown (H-B) failure criterion is an empirical failure criterion. The estimates of Hoek-Brown criterion parameters, such as the geological strength index (GSI) and the disturbance coefficient (D), are usually subjective. This paper focused on modifying the initial estimates of GSI and D to improve the accuracy of parameters. The nonlinear regression model (NLRM) of the Hoek-Brown failure criterion was proposed to analyze the rock parameters by using the sensitivity analysis and the displacement equation of the surrounding rocks. Then, a reasonable back analysis method was developed by introducing the differential evolution (DE), which was used to accurately obtain the parameters of the Hoek-Brown failure criterion in practical engineering. This method was successfully used to analyze the stability of the roadway in a deep coal mine. The results showed that the NLRM can better reflect the relationship between GSI, D, μ and the displacement of roadways, and the back analysis results are consistent with the filed monitoring results. This method can provide a helpful reference for modifying the influence of empirical and subjective factors on H-B parameters selection, and improving the accuracy of Hoek-Brown criterion parameters in the similar engineering applications.

A physical model experiment was conducted to study the surrounding rock failure mechanism for the roadway under deviatoric pressure from mining disturbance. During the excavation process, a self-developed deviatoric pressure reaction system was used to realize deviatoric pressure loading. Meanwhile, a digital photogrammetric measurement system and a static strain data collection system were utilized to obtain the deformation, strain and stress of the model. The deviatoric pressure stress field characteristic and deformation failure mechanism of roadway were investigated by synthetic analysis of experimental data and displacement vector diagram. The physical experimental results showed that mining disturbance had an inevitable influence on the formation of roadway deviatoric pressure, which caused the V-shaped distribution of pressure stress above the roadway. The V-shaped deviatoric pressure stress caused the roadway asymmetric deformation that was proportional to the deviatoric pressure stress above the roadway. And the asymmetric deformation further aggravated the degree of deviatoric pressure stress and formed a vicious cycle, which resulted in the instability of the roadway. In addition, a numerical simulation under deviatoric pressure was conducted to verify the accuracy of physical experimental results. This study can provide helpful references for researching the instability behavior of the roadway.

An experimental investigation was conducted in order to understand properties of grouts and grouted specimens. Three different cement types, i.e., composite ultrafine cement (CUC) that was independently developed, ultrafine cement (UC), and Portland cement (PC) were injected into broken red sandstone specimens on the basis of a self-designed grouting test equipment. After the grouting test, the effects on the mechanical behavior of grouted specimens were studied using an uniaxial compression test, macroscopic failure analysis and mesostructure analysis, as well as a comparison of the mechanical and structural properties of three types of grouted specimens was presented. The test results show that the compressive strength of grouted specimens improved in comparison to the rock residual strength, and the compressive strength of PC, UC and CUC grouted specimens increased by 23.0%, 59.6% and 101.5%, respectively. The failure modes of all grouted specimens were brittle failure, but only the CUC grouted specimen was failed along the new failure surfaces, indicating that CUC grouts can better bond the original cracks. The mesostructure characteristics obtained through the Digital 3D Video Microscope reveal the superior filling effect of the CUC grouts as well as verifying the macroscopic mechanical behavior.

Several years have passed since the Zika virus (ZIKV) pandemic reoccurred in 2015–2016. However, there is still a lack of proved protective vaccines or effective drugs against ZIKV. The peptide brevinin-2GHk (BR2GK), pertaining to the brevinin-2 family of antimicrobial peptides, has been reported to exhibit only weak antibacterial activity, and its antiviral effects have not been investigated. Thus, we analyzed the effect of BR2GK on ZIKV infection. BR2GK showed significant inhibitory activity in the early and middle stages of ZIKV infection, with negligible cytotoxicity. Furthermore, BR2GK was suggested to bind with ZIKV E protein and disrupt the integrity of the envelope, thus directly inactivating ZIKV. In addition, BR2GK can also penetrate the cell membrane, which may contribute to inhibition of the middle stage of ZIKV infection. BR2GK blocked ZIKV E protein expression with an IC50 of 3.408 ± 0.738 μΜ. In summary, BR2GK was found to be a multi-functional candidate and a potential lead compound for further development of anti-ZIKV drugs.

Objective To establish a nomogram for predicting the distant metastasis risk of pancreatic neuroendocrine tumors (pNETs) in elderly patients. Methods We extracted data of patients with diagnosis of pNETs at age ≥65 years old between 1973 and 2015 from the Surveillance, Epidemiology, and End Results (SEER) database. All eligible patients were divided randomly into a training cohort and validation cohort. Uni- and multivariate logistic regression analyses were performed on the training cohort to identify independent factors for distant metastasis. A nomogram was developed based on the independent risk factors using rms packages of R software, and was validated internally by the training cohort and externally by the validation cohort using C-index and calibration curves. Results A total of 411 elderly patients were identified, of which 260 were assigned to training cohort and 151 to validation cohort. Univariate and multivariate logistic regression analyses indicated the tumor site (body/tail of pancreas: odds ratio [OR]=2.282; 95% confidence interval [CI]: 1.174 – 4.436, P Conclusion The nomogram we established showed high discriminative ability and accuracy in evaluation of distant metastasis risk in elderly pNETs patients, and could provide a reference for individualized tumor evaluation and treatment decision in elderly pNETs patients.

As a high-efficiency and low-consumption mining mode, multi-middle section combined backfilling mining (MMSCBM) is becoming more and more widely used in metal mines. The geological mining conditions of Baixiangshan Iron Mine were taken as the simulation prototype. Similar model tests and numerical simulation experiments were used to study the surrounding rock disturbance, stope stability, surrounding rock stress, overburden settlement, and dynamic deformation of the ground surface during the MMSCBM process. The evolution process of the stope instability: the stable stage of the pillar, the large deformation stage of the pillar, the failure of some pillars, and the overall failure of the pillar. MMSCBM effectively buffered the excavation’s disturbance to the surrounding rock, adjusted the stress release mode, and changed the stress concentration area. The dynamic deformation laws of the overburden and the surface were summarized. The method of field monitoring was verified by numerical simulation calculation to study the disturbance degree of MMSCBM to the roadway and evaluate the safety of the roadway. This research has important significance and value for the wider application of the mining model.

The Sanshandao Gold Mine is located on a seabed, and the crown pillar is the main barrier to isolating seawater and preventing it from entering the mine. The thickness of the crown pillar and the size of the point pillars have a substantial impact on the reduction of resource waste and the economic development of the mine. Therefore, it is very important to determine a reasonable crown pillar thickness and point pillar size. In this paper, theoretical analysis and numerical simulation were performed to determine a reasonable thickness of the crown pillar and the size of the point pillar in the Sanshandao Gold Mine. According to the law of conservation of energy, a theoretical mechanical model was established based on the “crown pillar-point pillar” support system, and the thickness of the crown pillar, which corresponds to different section sizes of the point pillars, was obtained. Numerical simulation was carried out by combining Geologic Object Computer-Aided Design (GOCAD) and Fast Lagrangian Analysis of Continua in 3 Dimensions (FLAC3D). According to the failure criterion of the elastic strain energy density, the limit value of the elastic energy strain density coefficient of the ore body element and crown pillar was analyzed, the thickness of the crown pillar was determined, and the theoretical derivation result was verified. The point pillar with a section size of 4 m × 4 m was selected, and the crown pillar thickness was 50 m.

The excavation-loose zone (ELZ) is a key factor for the design and construction of underground engineering. In this study, ground-penetrating radar (GPR), non-invasive and effective method, is utilized to estimate the ELZ around an excavated soft coal seam with roof and floor consisting of soft rock seams. The picture segmentation method based on the 2D maximum between-cluster variance is conducted to optimize the radargrams obtained GPR, and then the ELZ can be accurately estimated by analyzing the radargrams. The results show that the magnitude of the ELZ different along different survey lines and is distinct at different positions along the same survey line. A large ELZ is concluded to surround the two sides of the coal walls and most of the floor. Meanwhile, due to complicated geological structure, local fractured zones exist widely within the ELZ. This case study is quite useful for understanding the range of the ELZ around a soft coal seam with soft rock seams in the coal wall and floor.

Ingestion of jujube pits is a common clinical problem, which can be difficult to diagnose and life-threatening if accompanied with intestinal perforation and peritonitis. In this study, 18 cases of intestinal perforation caused by ingestion of jujube pits were reviewed and summarized to discuss the clinical characteristics, diagnosis and treatments. From 2012 to 2018, a total of 18 patients diagnosed as intestinal perforation due to ingested pits of jujube in our center were retrospectively reviewed and the manifestations, laboratory tests, imaging examinations and treatment strategies were summarized. The patients comprised of 11 males and 7 females with an average age of 63.5 years. The main clinical manifestation was abdominal pain. Twelve patients (67%) presented to the emergency department with signs of localized peritonitis. CT imaging revealed positive findings in 17 (94%) patients. Conservative treatments were attempted in 3 patients, and the other 15 patients received emergency surgical exploration, where 7 patients had more than one perforation identified during surgery. Five patients were admitted in the surgical intensive care unit after surgery. The average length of stay of all 18 patients was 9.8 days (range 5–24 days). Ingestion of jujube pits is a common clinical problem and potentially leads to intestinal perforation and peritonitis. CT imaging is the first imaging modality of choice. Patients with milder symptoms might be managed with cautious conservative treatment, and patients with more than one perforation can be identified during surgery.

Drilling of large-diameter boreholes is regarded as an effective measure for rockburst prevention. By investigating the morphological characteristic and evolution of plastic zone in borehole surrounding rock, the pressure-relief mechanism of large-diameter borehole was ascertained, and the engineering application of large-diameter boreholes was assessed in the 13230 working face of Gengcun Coal Mine, Henan Province, China. The results showed that (1) the plastic zone in surrounding rock of borehole appear as circular, elliptical, and butterfly shapes, in which the maximum size of the butterfly wings of the plastic zone is several times larger than the borehole diameter; (2) under certain stress conditions, multiple large-diameter boreholes distributed in coal seam with rockburst risk lead to the generation and coalescence of large-range butterfly-shape plastic zone. They reduce the stress concentration and capacity for storing elastic energy of coal seam, thus reducing the rockburst risk of the coal seam; (3) large-diameter boreholes significantly decrease the stress concentration in front of the 13230 working face and improve the stress environment in the head entry, promoting the safe mining of the working face.

Background: Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths worldwide. Recent evidence indicates that circular RNAs (circRNAs) play important roles in tissue development, gene regulation, and carcinogenesis. However, whether circRNAs are involved in HCC progression and encode functional proteins remains largely unknown.Methods: Circular RNA microarrays were performed using three pathologically diagnosed HCC samples and their paired adjacent normal liver tissues. Cell invasion, migration, cell cycle, and apoptosis after circRNA overexpression were measured using a transwell culture system, a wound healing assay, and flow cytometry . Full-length, mutated, and truncated sequences of circEPS15 with a FLAG tag were inserted inside a circular expression vector. Western blotting was used to confirm circEPS15 expression and the requirement of internal ribosomal entry site (IRES) elements within the circRNA. The miRNA and mRNA expression profiles were obtained by analyzing data retrieved from The Cancer Genome Atlas (TCGA) database. We then constructed a ceRNA network of mRNAs, miRNAs, and circEPS15. Using tissue samples from own patients, we also verified certain analytical results with quantitative real-time PCR (qRT-PCR).Results: The expression of circEPS15 was downregulated in HCC tissues, and the survival curves showed that low circEPS15 levels were associated with poor overall survival in HCC patients. Overexpression of circEPS15 suppressed tumor invasion and migration by inhibiting the TJP1/CDH2/VIM signaling pathway and retarded cell cycle progression, but it had no effect on cell apoptosis. ceRNA analysis and qRT-PCR showed that there might be a circRNA (circEPS15)-miRNA (miR-24-3p)-mRNA (CIDEA) network in HCC. The spanning junction open reading frame in circEPS15 driven by IRES encoded a novel protein.Conclusions: Endogenous circEPS15 plays a novel role in repressing HCC through the ceRNA network and encoding a functional protein.

In view of the serious threat of gas accumulation in the coal mine goaf and the limitations of the existing gas sealing materials, the orthogonal experiment was developed to study a new type of foamed concrete for mine gas sealing. Dry density, gas permeability, and compressive strength were studied as the material indicators according to the demands of the gas isolation material in the coal mine goaf, and the experimental results showed that foam content was the most important factor. Meanwhile, the optimum mix was selected according to the influence of foam content as well as the engineering requirement. Then two application modes of this foamed concrete for goaf gas isolation were put forward, after which the convection-diffusion model of gas was built by COMSOL Multiphysics (COMSOL Inc., Stockholm, Sweden) to reveal the mechanism of different application modes using the parameters of the new foamed concrete. Simulation results showed that this foamed concrete used as isolating material for goaf gas could significantly decrease the gas concentration in workface, which can provide a reference for similar engineering.

Curvature estimation is essential for many computational techniques on point cloud, which can be obtained, for example, by scanning real-world objects by a 3D scanner. We propose a novel technique to directly estimate mean curvature and Gaussian curvature on point cloud. We view the object surface as the indicator function of the scanned object and then smooth the function. Curvatures can be computed from the gradient and Hessian of the smoothed indicator function explicitly. We use an integral formula to approximate the gradient and Hessian on point cloud. The surface approximation and smoothing filter are implicit inside the integral formulas. And the experiments show our method is the fastest method that outputs mean curvature and Gaussian curvature with accuracy comparable to other established methods.

To study the mechanical properties of argillaceous weakly cemented rock under dynamic loading, a sample reconstituted and graded loading scheme is firstly designed, and then the reorganization rock sample is used as the research object. Using a Hopkinson pressure bar test, the responses of an argillaceous weakly cemented rock mass under different reorganization loads and different impact velocities is studied, and changes in specimen shape after impact are also analyzed. The study found that with increased of the recombination load, the amplitude of the transmitted wave increases. With increasing impact velocity, the rate of the increase in the incident wave amplitude is much larger than that of the transmission wave amplitude. The dynamic stress&ndash, strain curve can be divided into a compaction stage, an approximate linear elastic stage, a microcrack growth stage and a strain softening stage. The larger the reorganization load is, the less obvious the compression stage of the stress&ndash, strain curve is, and the greater the elastic modulus is. The peak strength and elastic modulus increase with increasing strain rate before 500 s&minus, 1. When the reorganization load is increased, the deformation decreases, and its impact resistance increases. With increasing impact velocity, the deformation of the specimen increases.

A series of triaxial compression experiments of intact and cracked sandstone with different degrees of damage were carried out using a rock mechanics servo-controlled system. Based on the experimental results, the influence of the confining pressure and damage on the peak strength, residual strength parameters, deformation parameters, and failure modes of cracked sandstone was investigated in detail. The results show that the strength and deformation behavior depends on not only the confining pressure but also the damage. The peak and residual strength of intact and cracked specimens increases linearly with increasing confining pressure, which is in good agreement with the linear Mohr-Coulomb criterion. The peak strength and equivalent cohesion of cracked specimens decreases linearly and exponentially with increasing damage, respectively. However, the internal friction angle is independent of damage. The elastic and secant modulus of cracked specimens increases linearly with increasing confining pressure but decreases with increasing damage. Then the effects of the confining pressure and damage on the peak strain and failure modes of cracked specimens are also analyzed in detail, indicating the transition of the failure modes from single shear failure to multiple shear failure with increasing damage.

Flow blockage accidents in rectangular fuel assembly were investigated by three-dimensional CFD method in detail. Totally six coolant channels of the fuel assembly were modeled. Meanwhile, in order to make understand of the thermal hydraulic characteristics of the flow blockage accidents comprehensively, three coolant channels which included the obstructed channel were investigated and analyzed thoroughly based on simulation results. RELAP5 calculation was performed here to compare with CFD simulation results under non-blocked condition, and the comparison results indicated approximate agreement of such two types of results. On the basis of the CFD simulation, velocity and temperature profiles were discussed for some typical blockage cases, and conclusion was drawn that the redistribution of the mass flow rates occurred after the formation of the blockage, and due to the formation of obstruction, temperature of the coolant and the fuel increased rapidly which caused higher peak temperature in the blockage channel. Simultaneously, the increasing flow resistance would lead to the existence of jet-flow and reverse flow in the obstructed channel. In addition, DNBR calculation indicated that heat flux on the cladding surface would not exceed critical heat flux, thus DNB would not occur under the investigated situation.

The deformations and failures of coal wall in front of a working face cause serious mining difficulties. This paper presents the results of the physical model experiments that were conducted to study the deformation and failure process of coal seam in front of a longwall working face. In order to simulate the formation process of the bearing pressure on the roof rock seam, the special loading device was designed. The stepped loadings were applied on the top side of a sample to simulate the non-uniform loading on the coal seam. The proposed integrity coefficient was used to evaluate the failures of the coal seam. Results show that in the advancing process of a working face, the coal seam undergoes a complex fracturing process and the fracturing of coal seam is closely related to the distance from the coal wall. When the coal body is quite close to the wall of a working face, different types of fracture surfaces appear. The fracture surfaces near the front face of coal wall are tensile while the fracture surfaces away from the front face of coal wall are shear and tensile or shear. These results are useful for understanding the deformation and failure of coal wall.

The management of coolant leakage in a Nuclear Reactor Containment is important to ensure the integrity of the second barrier and the safe operation of a nuclear power plant. In the nuclear plant, several reliable leak detection systems continuously monitored coolant leak. In this paper, we introduced a new unidentified leak detection method based on monitoring the condensate in the ventilation coolers. After built a heat exchanger model of the cooler and introduced the fan model in the commercial CFD code, we validated models and got a reasonable simulation of the leak steam condensate on the cooler. Then we built the detail three-dimensional (3D) PWR containment geometry model (including internal structures and ventilation systems). Based on the detailed flow field in this containment and the moisture condensation theory, we could get the condensate character on the coolers of the EVR ventilation system after unidentified leak. Analyses were carried out to quantify the condensate after the 1.0gpm (gal/min) and 1.5gpm leak at hot leg and cold leg located at the reactor pit and steam generator room. The result indicated that the start condensation time of 1.0gpm leak was about 75min and 45min of 1.5gpm, and the leak location had slight influence on the start condensation time. This work would contribute to a reasonable design of a leakage detection method for the unidentified leak in the containment.

Thermal-hydraulic performance in the reactor core was an essential factor in the nuclear power plant design. In this study, we analyzed the three-dimensional (3-D) thermal-hydraulic characteristic of reactor core based on porous media method. Firstly, a 3-D rector pressure vessel (RPV) model was built, including the inlet leg nozzle, downcomer, lower plenum, reactor core, upper plenum and outlet leg nozzle. Porous media model was used to simplify the reactor core and upper plenum. The commercial CFD code ANSYS CFX was employed to solve the governing equations and provide the 3-D local velocity, temperature and pressure field. After appropriate parameters and turbulent model being carefully selected, the simulation was validated against the 1:5 scaled steady-state hydraulic test. The predicted hydraulic parameters (normalized flowrate distribution and pressure drop) were in good agreement with the test results. And the predicted thermal parameters agreed well with the designed values. The validation indicated that this method was practicable in analyzing the 3-D thermal-hydraulic phenomena in the RPV. Finally, the thermal-hydraulic features in reactor core were analyzed under the condition of the Steam Generator Tube Rupture (SGTR) accident. The simulation results showed that the coolant temperature increased gradually from the center to the periphery in the reactor core in the accident. But the temperature decreased to safety level rapidly after the reactor shutdown and safety injection operation. The reactor core could keep in a safe state if appropriate safety operations were performed after accidents.

In the present study, the chemical constituents and inhibitory effects of Chinese olive leaf tea (OLT) on α-amylase, α-glucosidase, and its lipid-lowering effects on obese mice induced by a high fat diet were evaluated. In total, 17 compounds including hydroxytyrosol, hydroxytyrosol-glucoside were tentatively identified as main compounds of OLT with authentic compounds or referring to published articles and accessible databases. In total 105 volatile compounds were identified, in which hexanal, benzaldehyde and nonanal were the main aroma compounds. The bioassay showed that the IC50 values of the OLT on α-amylase and α-glucosidase were 0.2102 g/mL and 2.925 mg/mL, respectively. It also indicated that the OLT is effective in improving the glucose homeostasis by oral starch tolerance test (OSTT). The experimental results in vivo also indicated that OLT significantly improved body weight, liver weight, abdominal fat, plasma levels of lipids, hepatic and plasma malondialdehyde (MDA) levels compared with obese mice fed high-fat diet. The OLT can enhance the antioxidant enzymes’ activities (SOD and GSH-Px), meanwhile prevent the hepatic inflammation induced by high-fat diet. In summary, OLT has a potential application in preventing metabolic syndromes.