Experimental and Numerical Analysis of Rock Burst Tendency and Crack Development Characteristics of Tianhu Granite

Rock burst is a serious nonlinear dynamic geological hazard in underground engineering construction. In this paper, a true triaxial unloading rock burst experiment and numerical simulation are carried out on Tianhu granite to investigate the rock burst tendency and crack development characteristics of surrounding rock after excavation. The experiment and numerical simulation process monitored the rock burst stress path to determine the rock burst stress. According to the evolution law of the frequency and amplitude of rock burst acoustic emission monitoring, the shape characteristics of rock burst fragments are analyzed. The rock burst numerical simulation analysis is carried out by the PFC software, and the temporal and spatial evolution law of cracks is obtained. The research results show that the laboratory experiment and numerical simulation of Tianhu granite have rock burst strengths of 163.4 MPa and 161 MPa, respectively, and the average rock burst stress ratio is 8.38, that is, the Tianhu granite has a low rock burst tendency. During the rock burst, the development of tensile cracks will produce flaky debris, and the development of shear cracks will produce lumpy debris. Rock burst will happen when the crack growth rate to be exceeded the unloading crack growth rate; therefore, it can be used as a precursor signal for the occurrence of rock burst

Variant rs2200733 and rs10033464 on chromosome 4q25 are associated with increased risk of atrial fibrillation after catheter ablation: Evidence from a meta-analysis

Background: Common genetic polymorphisms at chromosome 4q25 were associated with increased susceptibility to atrial fibrillation (AF). However, it remained controversial whether these variants could be used as risk predictors for AF recurrence after catheter ablation. We therefore performed a metaanalysis to quantify the association between rs2200733 C>T/rs10033464 G>T and AF recurrence. Methods: Relevant studies were systematically retrieved from PubMed, Web of Science, Elsevier database and Cochrane library through November 2016. Data were abstracted and pooled using Stata 12.0 software. Results: A total of 2,145 patients undergoing catheter ablation were included. Patients with rs2200733 TT or TT+CT showed an overall increased susceptibility to AF recurrence (homozygous model [TT vs. CC]: odds ratio [OR] = 2.03, 95% confidence interval [CI] 1.49–2.76, p = 0.000; dominant model [TT+TC vs. CC]: OR = 1.48, 95% CI 1.17–1.87, p = 0.001; recessive model [TT vs. TC+CC]: OR = 1.88, 95% CI 1.12–3.15, p = 0.017). Subgroup analysis also identified a positive relation in Caucasians and late recurrence of AF in allelic, homozygous and dominant comparison. Moreover, a significant increased risk of AF recurrence was observed in patients with rs10033464 TG or TT+TG (heterozygous model [TG vs. GG]: OR = 1.46, 95% CI 1.01–2.12, p = 0.047; dominant model [TT+TG vs. GG]: OR = 1.51, 95% CI 1.04–2.17, p = 0.029). Conclusions: After catheter ablation, rs2200733 (TT or TT+TC) and rs10033464 (TT+TG or TG) were associated with increased risk of AF recurrence

Fecal microbiota transplantation in a child with severe ASD comorbidities of gastrointestinal dysfunctions—a case report

Autism spectrum disorder (ASD) is a neurodevelopmental disorder defined by social communication impairments and restricted, repetitive behaviors. In addition to behavioral interventions and psychotherapies, and pharmacological interventions, in-depth studies of intestinal microbiota in ASD has obvious abnormalities which may effectively influenced in ASD. Several attempts have been made to indicate that microbiota can reduce the occurrence of ASD effectively. Fecal microbiota transplantation (FMT) is a type of biological therapy that involves the transplant of intestinal microbiota from healthy donors into the patient’s gastrointestinal tract to improve the gut microenvironment. In this case report, we describe a case of child ASD treated by FMT. The patient have poor response to long-term behavioral interventions. After five rounds of FMT, clinical core symptoms of ASD and gastrointestinal(GI) symptoms were significantly altered. Moreover, the multiple levels of functional development of child were also significantly ameliorated. We found that FMT changed the composition of the intestinal microbiota as well as the metabolites, intestinal inflammatory manifestations, and these changes were consistent with the patient’s symptoms. This report suggests further FMT studies in ASD could be worth pursuing, and more studies are needed to validate the effectiveness of FMT in ASD and its mechanisms

Children neuropsychological and behavioral scale-revision 2016 in the early detection of autism spectrum disorder

BackgroundThe Children Neuropsychological and Behavioral Scale-Revision 2016 (CNBS-R2016) is a widely used developmental assessment tool for children aged 0–6 years in China. The communication warning behavior subscale of CNBS-R2016 is used to assess the symptoms of autism spectrum disorder (ASD), and its value of >30 points indicates ASD based on CNBS-R2016. However, we observed that children with relatively lower values were also diagnosed with ASD later on in clinical practice. Thus, this study aimed to identify the suitable cutoff value for ASD screening recommended by the communication warning behavior of CNBS-R2016.Materials and methodsA total of 90 typically developing (TD) children and 316 children with developmental disorders such as ASD, developmental language disorder (DLD), and global developmental delay (GDD; 130 in the ASD group, 100 in the DLD group, and 86 in the GDD group) were enrolled in this study. All subjects were evaluated based on the CNBS-R2016. The newly recommended cutoff value of communication warning behavior for screening ASD was analyzed with receiver operating curves.ResultsChildren in the ASD group presented with lower developmental levels than TD, DLD, and GDD groups in overall developmental quotient assessed by CNBS-R2016. We compared the consistency between the scores of communication warning behavior subscale and Autism Behavior Checklist (ABC), Childhood Autism Rating Scale (CARS), Autism Diagnostic Observation Schedule, second edition (ADOS-2), and clinical diagnosis for the classification of ASD at a value of 30 based on the previously and newly recommended cutoff value of 12 by the CNBS-R2016. The Kappa values between the communication warning behavior and ABC, CARS, ADOS-2, and clinical diagnosis were 0.494, 0.476, 0.137, and 0.529, respectively, with an agreement rate of 76.90%, 76.26%, 52.03%, and 82.27%, respectively, when the cutoff point was 30. The corresponding Kappa values were 0.891, 0.816, 0.613, and 0.844, respectively, and the corresponding agreement rate was 94.62%, 90.82%, 90.54%, and 93.10%, respectively, when the cutoff point was 12.ConclusionThe communication warning behavior subscale of CNBS-R2016 is important for screening ASD. When the communication warning behavior score is 12 points or greater, considerable attention and further comprehensive diagnostic evaluation for ASD are required to achieve the early detection and diagnosis of ASD in children

Fracture evolution of the main roof in gob-side entry retaining by roof cutting of an inclined coal seam

During the application of gob-side entry retaining by roof cutting in inclined coal seams, the boundary conditions of the main roof in the goaf will change, resulting in the special characteristics of its fracture evolution. This article established a main roof elastic mechanics model through theoretical analysis and obtained the stress expression of any point on the main roof, analyzed the stress distribution characteristics and fracture evolution law of the main roof, finally, and revealed the unloading mechanism of the overburden in the cutting roof of goaf by combining with field mining pressure data. The results show that the stress value on the main roof is related to the dip angle, the poison's ratio, and the geometry parameters of the working face. The main roof stress presented an asymmetric distribution in the inclined direction. The fracture mode of the main roof is the “U-Y” mode under the first weighting and the “L-Y” mode under periodic breakage. The pressure on the upper part of the working face increased, while the lower part decreased according to field mining pressure data. There are two reasons for the reduction of pressure in the lower part of the working face, on the one hand, the reduction of the area of the key block A leads to a decrease in load, on the other hand, the gangue filling and supporting effect of the lower part of the goaf. The surrounding rock of the gob-side entry is not obviously affected by the dynamic pressure, and the deformation is small, achieving a good retaining effect

Adsorption Induced Indirect-to-Direct Band Gap Transition in Monolayer Blue Phosphorus

In this work, we systematically studied adsorption induced indirect-to-direct band gap transition in monolayer blue phosphorus from first-principles calculations by combining one-shot GW approximation and the Bethe-Salpeter equation. Our results revealed that surface adsorption (i.e., O₂, −OH, −COOH, and −CN) strongly modifies the conduction and valence band edges, resulting in an indirect-to-direct band gap transition. More importantly, the direct band gap can be dramatically tuned by either the in-plane strain or the coverage ratio of adsorbates, which enables monolayer blue phosphorus to efficiently adsorb visible light. The mechanism of strain effect and surface adsorption on band gap tuning was deeply discussed. Moreover, our results clearly showed that the adsorbates have an important influence on the exciton binding energies (EBE), while the coverage of adsorbates play a crucial role in the linear scaling behavior between EBE and quasi-particle band gap. Our findings suggest that monolayer blue phosphorus has potential applications in electro-optical devices

A Study on the Relationship between the Rank of Input Data and the Performance of Random Weight Neural Network

Random feature mapping (RFM) is the core operation in the random weight neural network (RWNN). Its quality has a significant impact on the performance of a RWNN model. However, there has been no good way to evaluate the quality of RFM. In this paper, we introduce a new concept called dispersion degree of matrix information distribution (DDMID), which can be used to measure the quality of RFM. We used DDMID in our experiments to explain the relationship between the rank of input data and the performance of the RWNN model and got some interesting results. We found that: (1) when the rank of input data reaches a certain threshold, the model’s performance increases with the increase in the rank; (2) the impact of the rank on the model performance is insensitive to the type of activation functions and the number of hidden nodes; (3) if the DDMID of an RFM matrix is very small, it implies that the first ��k singular values in the singular value matrix of the RFM matrix contain too much information, which usually has a negative impact on the final closed-form solution of the RWNN model. Besides, we verified the improvement effect of intrinsic plasticity (IP) algorithm on RFM by using DDMID. The experimental results showed that DDMID allows researchers evaluate the mapping quality of data features before model training, so as to predict the effect of data preprocessing or network initialization without model training. We believe that our findings could provide useful guidance when constructing and analyzing a RWNN model