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Abstract To address the need for rapid repair and emergency support of traffic capacity in damaged tunnels, this study proposed a new structure combining arches assembled from steel plates and shotcrete with high early strength and performance (hereinafter referred to as the steel-shotcreting structure) based on the concept of “modular assembly, rapid formation, and temporary-permanent combination”. It is designed to replace the traditional cast-in-place concrete arch repair technique. Based on the principle of equivalent stiffness, the load borne by the steel arches in the new support structure was analyzed. Numerical analyses were performed to examine the influences of steel arch spacing and the types of I beams and channel steel on the load-bearing capacity of the new structure under varying surrounding rock and tunnel span conditions. The new steel-shotcreting structure was applied in a tunnel in China and its load-bearing capacity was compared with that of traditional steel arch support structures. The results show that its load-bearing proportions were 13% and 18% under the conditions of grade IV and V surrounding rock, respectively. In large-span tunnels with unstable surrounding rock, reducing the longitudinal spacing of plate steel arches, upgrading the channel steel model for longitudinal connectors, and increasing the size of I beams can enhance the load-bearing performance of the whole structure. Compared to traditional steel arch support structures, the new structure is more adaptable, flexible, and stable and demonstrates better support effects. The research findings provide a theoretical basis and technical support for the rapid repair of damaged tunnels.

BackgroundMulti-slice spiral computerized tomography (MSCT) can be used as an auxiliary diagnosis of chest radiography in diagnosis of pneumoconiosis, but there are few studies on the correlations between interstitial images and stage classification of coal workers' pneumoconiosis in the existing literature. ObjectiveTo present MSCT imaging manifestations and distribution characteristics of coal workers' pneumoconiosis and complications, evaluate correlations between coal workers' pneumoconiosis stages and pulmonary interstitial lesions, and provide a reliable imaging diagnosis basis for pneumoconiosis interstitial lesions. MethodsFrom June 2022 to June 2023, a total of 1002 patients with coal workers' pneumoconiosis confirmed by the pneumoconiosis diagnostic and identification group in the Department of Occupational Diseases of the Emergency General Hospital were enrolled. MSCT was used to observe the abnormal imaging manifestations of the lungs of coal workers' pneumoconiosis patients and the diseases of pulmonary fibrosis related to their own diseases (thickening of the interlobular septum, bronchial perivascular interstitial mass thickening, parenchymal banding, subpleural line, intralobular interstitial thickening, honeycomb, and subpleural interstitial thickening), the occurrence of coal workers' pneumoconiosis and complications (old tuberculosis, active tuberculosis, pneumonia, atelectasis, lung cancer, bronchiectasis), and the density, size, and location of pneumoconiosis nodules. Imaging data were analyzed and statistically processed. ResultsAll 1002 patients were male, with an average age of (60.71±6.87) years and an average dust exposure time of (23.01±7.80) years. Among them, there were 470 patients with stage I, 422 patients with stage II, and 110 patients with stage III. There were significant differences in the distribution of thickening of the interlobular septum, bronchial perivascular interstitial mass thickening, parenchymal banding, intralobular interstitial thickening, subpleural interstitial thickening, and honeycomb across different stages (P

Background It is a research hotspot to study the changes of metabolites and metabolic pathways in the process of coal worker's pneumoconiosis (CWP) by metabonomics and to explore its pathogenesis. ObjectiveTo study the change of metabolites in bronchoalveolar lavage fluid (BALF) of patients with CWP and explore the metabolic regulation mechanism of the disease. MethodsPatients with CWP who met the national diagnostic criteria according to Diagnosis of occupational pneumoconiosis (GBZ 70-2015) and underwent massive whole lung lavage were selected as the case group, and patients with tracheostenosis who underwent bronchoscopy were selected as the control group. BALF samples were collected from the cases and the controls. After filtering out large particles and mucus, the supernatant was stored in a −80 ℃ refrigerator. The samples were detected and analyzed by liquid chromatography-mass spectrometry after adding extraction solution, cold bath ultrasonication, and high-speed centrifugation, and the metabolic profiles and related data of CWP patients were obtained. The differential metabolites related to the occurrence and development of CWP were screened by multiple statistical analysis; furthermore, we searched the Kyoto Encyclopedia of Genes and Genomes (KEGG) database for potential metabolic pathways involved in the progression. ResultsThere was no significant difference in the general conditions of the subjects, such as weight, height, age, and length of service among the stage I group, the stage II group, the stage III group, and the control group (P˃0.05). When comparing the CWP stage I group with the control group, 48 differential metabolites were screened out, among which 14 were up-regulated and 34 were down-regulated. A total of 66 differential metabolites were screened out between the patients with CWP stage II and the controls, 14 up-regulated and 52 down-regulated differential metabolites. Compared with the control group, 63 differential metabolites were screened out in the patients with CWP stage III, including 11 up-regulated and 52 down-regulated differential metabolites. There were 36 differential metabolites that may be related to the occurrence of CWP, among which 11 differential metabolites were up-regulated, and 25 were down-regulated. Four significant differential metabolic pathways were identified through KEGG database query: linoleic acid metabolic pathway, alanine metabolic pathway, sphingolipid metabolic pathway, and glycerophospholipid metabolic pathway. ConclusionThe metabolomic study of BALF show that there are 36 different metabolites in the occurrence and development of CWP, mainly associating with linoleic acid metabolism, alanine metabolism, sphingolipid metabolism, and glycerophospholipid metabolism pathways.

BackgroundPneumoconiosis is a widespread occupational disease in China at present. As a type of lung diseases, its pathological damage is mainly irreversible fibrotic changes in the lungs. Several studies have shown that the occurrence and development of lung diseases such as coal workers' pneumoconiosis are closely related to intestinal flora. ObjectiveTo observe intestinal flora of coal workers' pneumoconiosis patients based on the results of 16SrDNA high-throughput sequencing and evaluate the changes of intestinal flora after treatment with tetrandrine tablets. MethodsA total of 80 patients with coal workers' pneumoconiosis attending the outpatient clinic of the Department of Occupational Diseases of the Emergency General Hospital from April to July 2022 were enrolled. All patients were treated with tetrandrine tablets for 4 weeks, with group A before the treatment of tetrandrine tablets and group B after the treatment. In the same period, 24 healthy controls (group C) were set up. Stool samples were collected before and after the treatment. Using 16SrDNA high-throughput sequencing, gene V3-V4 sequencing technology, and bioinformatic analysis platform, we evaluated the intestinal flora after treatment by groups. ResultsThe dominant flora at the phylum level and genus level were the same across three groups. The relative abundances of phylum Bacteroidetes, Bifidobacterium, Bacteroides, and Facealibacterium in groups B and C were higher than those in group A, and the relative abundances of phy-lum Actinobacteria, genus Blautia, and genus Romboutsia in groups B and C were lower than those in group A (P＜0.05). The relative abundances of genus Clostridium, genus Megamonas, and genus Lactobacillus in group C was lower than that in groups A and B (P＜0.05). The alpha diversity analysis showed that the Chao1 index was higher in group A than in group C (P＜0.01). Compared with group A, the Shannon index was higher in group B, and the increases of Simpson index were all statistically significant in stage I patients (P＜0.05), but the differences in Chao1 index were not statistically significant (P＞0.05). The differences in the values of Chao1 index, Shannon index, and Simpson index in stage Ⅱ and stage III patients were not statistically significant (P＞0.05). The beta diversity analysis showed that the difference in flora structure between group A and group C was statistically significant (P＜0.05); the differences in flora structure before and after treatment in the same stage patients were statistically significant (P＜0.05). The partial least squares discriminant analysis (PLS-DA) showed that there were significant differences between group A and group C, and between group A and group B. The LEfSe analysis showed that the significant markers contributing to the differences were basically the same in stage I, stage Ⅱ, and stage Ⅲ after treatment, which were mainly phylum Bacteroidetes and its subordinate groups, class Negativicutes, or-der Selenomonas, and genus Facealibacterium. ConclusionThere are differences in the distribution of flora between coal workers' pneumoconiosis patients and healthy individuals, and the structure and relative abundance of intestinal flora are changed and the number of beneficial flora is increased after treatment with tetrandrine tablets.

BackgroundAt present, the practice of pulmonary rehabilitation for pneumoconiosis in China is in a primary stage. The basis for formulating an individualized comprehensive pulmonary rehabilitation plan is still insufficient, which is one of the factors limiting the development of community-level rehabilitation work. ObjectiveTo formulate an exercise prescription based on maximum heart rate measured by cardiopulmonary exercise test (CPET), conduct an individualized comprehensive pulmonary rehabilitation program with the exercise prescription for patients with stable pneumoconiosis, and evaluate its role in improving exercise endurance and quality of life, thus provide a basis for the application and promotion of pulmonary rehabilitation. MethodsA total of 68 patients were recruited from the Occupational Disease Prevention Hospital of Jinneng Holding Coal Industry Group Co., Ltd. from April to August 2022 , and were divided into an intervention group and a control group by random number table method, with 34 cases in each group. All the pneumoconiosis patients participated in a baseline test. The control group was given routine drug treatment, while the intervention group received multidisciplinary comprehensive pulmonary rehabilitation treatment on the basis of routine drug treatment, including health education, breathing training, exercise training, nutrition guidance, psychological intervention, and sleep management, whose exercise intensity was determined according to the maximum heart rate provided by CPET. The rehabilitation training lasted for 24 weeks. Patients were evaluated at registration and the end of study respectively. CPET was used to measure peak oxygen uptake per kilogram (pVO2/kg), anaerobic threshold (AT), carbon dioxide equivalent of ventilation (EqCO2), maximum metabolic equivalent (METs), and maximum work (Wmax). The modified British Medical Research Council Dyspnea Questionnaire (mMRC), Self-rating Anxiety Scale (SAS), Self-rating Depression Scale (SDS), Pittsburgh Sleep Quality Index (PSQI), Chronic Obstructive Pulmonary Disease Assessment Test (CAT), and Short Form of Health Survey (SF-36) were used to evaluate the potential effect of the comprehensive pulmonary rehabilitation program. ResultsAmong the included 68 patients, 63 patients were having complete data, then 31 cases were assigned in the control group and 32 cases in the interventional group. Before the intervention, there was no significant difference in pVO2/kg, AT, EqCO2, METs, or Wmax between the two groups (P>0.05). At the end of the trail, the indicators like pVO2/kg [(19.81±2.38) mL·(min·kg)−1], AT [(14.48±2.33) mL·(min·kg)−1], METs (5.64±0.69), and Wmax [(85.25±14) W] of patients in the intervention group were all higher than those [(13.90±2.37) mL·(min·kg)−1, (11.70±1.94) mL·(min kg)−1, (3.97±0.70), and (61.77±14.72) W, respectively] in the control group (P0.05). At the end of the trail, the mMRC score (1.16±0.57), SAS score (27.93±2.12), SDS score (26.48±1.44), PSQI score (1.08±0.88), and CAT score (4.34±3.28) of patients in the intervention group were lower than those [(2.03±0.83), (35.87±6.91), (34.23±6.65), (5.37±3.03), and (13.87±7.53), respectively] in the control group (P0.05). ConclusionComprehensive pulmonary rehabilitation can increase the oxygen intake and exercise endurance of pneumoconiosis patients, ameliorate dyspnea symptoms, elevate psychological state and sleep quality, and improve the quality of life.

Abstract BackgroundRemovable partial denture (RPD) design is crucial to long-term success in dental treatment, but shortcomings in RPD design training and competency acquisition among dental students have persisted for decades. Digital production is increasing in prevalence in stomatology, and a digital RPD (D-RPD) module, under the framework of the certified Objective Manipulative Skill Examination of Dental Technicians (OMEDT) system reported in our previous work, may improve on existing RPD training models for students. ObjectiveWe aimed to determine the efficacy of a virtual 3D simulation–based progressive digital training module for RPD design compared to traditional training. MethodsWe developed a prospective cohort study including dental technology students at the Stomatology College of Chongqing Medical University. Cohort 1 received traditional RPD design training (7 wk). Cohort 2 received D-RPD module training based on text and 2D sketches (7 wk). Cohort 3 received D-RPD module pilot training based on text and 2D sketches (4 wk) and continued to receive training based on 3D virtual casts of real patients (3 wk). RPD design tests based on virtual casts were conducted at 1 month and 1 year after training. We collected RPD design scores and the time spent to perform each assessment. ResultsWe collected the RPD design scores and the time spent to perform each assessment at 1 month and 1 year after training. The study recruited 109 students, including 58 (53.2%) female and 51 male (56.8%) students. Cohort 1 scored the lowest and cohort 3 scored the highest in both tests (cohorts 1-3 at 1 mo: mean score 65.8, SD 21.5; mean score 81.9, SD 6.88; and mean score 85.3, SD 8.55, respectively; PPPPPPP ConclusionsCohort 3 obtained the highest score at both time points with retention of competency at 1 year, indicating that progressive D-RPD training including virtual 3D simulation facilitated improved competency in RPD design. The adoption of D-RPD training may benefit learning outcomes.

BackgroundResidual varus after Oxford unicompartmental knee arthroplasty (UKA) happens frequently. This study aims to evaluate the pre-operative contributing factors of residual varus.MethodsA total of 1,002 knees (880 patients, 201 patients were male, and 679 were female) underwent Oxford UKA in the Orthopedic Surgery Department of the Beijing Jishuitan Hospital from March 2018 to April 2021. The mean age of the patient was 64.7 ± 7.7 years. To assess residual varus, the full-length lower extremity is placed upright for EOS imaging, with the knee fully extended. The angle of post-operative residual varus was measured as described by Noyes et al. Of the knees studied, they were either categorized into an under-corrected group (post-operative Noyes angle >5°) or a corrected group (post-operative Noyes angle ≤5°). Age, gender, body mass index (BMI), range of motion (ROM), Clinical American Knee Society Score (Clinical AKSS), and Function American Knee Society Score (Function AKSS) were compared. The following additional parameters were measured: pre-operative Noyes angle, lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), the posterior slope of the proximal tibia angle (PPTA), joint line converge angle (JLCA), and fixed flexion deformity (FFD).ResultsThere was no statistically significant difference between the two groups in regards to gender (p = 0.428), surgical leg (p = 0.937), age (p = 0.851), BMI (p = 0.064), pre-operative Clinical AKSS (p = 0.206) and Function AKSS (p = 0.100). However, pre-operative ROM statistically differed between the two groups (p

Underground construction will have more or less adverse effects on adjacent existing buildings with more and more existing buildings above ground. However, this situation has only been reported by a small number of researchers. In view of this, this article takes the existing airport line shaft and horizontal passage project in the western suburb of Beijing Metro Line 12 as the background to study the impact of the construction of subway station and shaft passage on the adjacent existing railway. Based on the above project reality, under the action of pavement load, the effects of different parameters (the distance between the surface measuring point and the middle line of the transverse passage and the substep of construction loading sup step) on the surface settlement and track deformation of the shaft and cross-passage through the existing railway are studied by numerical analysis method. The calculation results show that the construction method of shaft and cross passage is reasonable. The comprehensive reinforcement measures of subgrade, rail and hole are effective, effectively controlling the deformation of subgrade and rail within the standard value (surface settlement ≤60 mm, rail deformation ≤6 mm). In addition, the numerical simulation data can better represent the actual situation as a whole.

It is difficult to monitor the deformation of a rock mass in front of a tunnel owing to the large buried depth and complex geological conditions. In this study, by using a self-designed model test box as a carrier and using loess, sand, gypsum, cement, and water as the raw materials, the class V materials similar to the surrounding rock are obtained through an orthogonal test. These are used to study the deformation law of a rock mass in front of a tunnel in different ground stress soft rock. The results show that similar materials for the surrounding rock can meet the needs of the testing concerning the physical and mechanical properties and have economic and environmental protection advantages. The three-dimensional loading of a similar geological body is used to simulate the state of the rock mass. The real-time monitoring of the rock mass stress and deformation is conducted during a simulation of tunnel excavation, and the deformation laws of the rock mass and surrounding rock in front of the tunnel are obtained. In the range of 0.26 times the tunnel diameter in front of the tunnel in the high ground stress soft rock, the deformation of the core rock mass is the largest part of the tunnel deformation. Therefore, to reasonably control the advanced deformation of the tunnel, it is necessary to pre-reinforce the core rock mass within 0.26 times the tunnel diameter in front of the tunnel. At 1 times the diameter in front of the face, a longitudinal load-bearing arch is formed in the rock mass, and this effectively controls the extrusion deformation of the core rock mass to expand forward.

Rockburst physical model test, as one of the important means to study deep tunnel engineering, reflects the main influencing factors of rockburst into the model test through similar theory, so as to reveal the formation mechanism, influencing factors and evolution law of different types of rockburst in deep tunnels. In order to study the mechanical properties of white sandstone in deeply buried tunnels at high ground temperatures, materials suitable for conducting rockburst physical and mechanical tests were developed on the basis of the Daqian Shi Ling tunnel project, and similar material ratios were preferentially selected on the basis of white sandstone. Judged by the rock burst propensity, similar materials with low strength and high brittle characteristics, can better simulate the characteristics of white sandstone, and all show a strong propensity to rock burst, is the ideal rock burst similar materials. Uniaxial compressive tests were conducted on similar materials and the original rock at different temperatures, and comparative analysis was performed. Through the study of stress, displacement and modulus of elasticity, it was concluded that the compressive strength of similar materials gradually increased with temperature in the range of 20-100°C, and the vertical displacement at peak strength decreased with increasing temperature. The damage forms of white sandstone and similar materials at different temperatures were comparatively analyzed, and it was obtained that the damage forms of white sandstone and similar materials were basically the same, with a few specimens showing tensile and shear damage, and most specimens showing the form of combined tensile and shear damage. The study of rock burst similar materials and the development of the failure characteristics of rock burst under the action of thermal coupling are of great significance to the mechanism of rock burst generation and prediction.

In this study, a tunnel temperature field model test bed is built according to the similarity principle to study the variation law of temperature in the tunnel in the cold season. According to the variation law of temperature in the tunnel, a new active thermal insulation measure, namely, an air curtain system, is developed. According to the principle of flow function superposition and heat balance, the governing equation of air curtain system is obtained. Taking the Zhengpantai tunnel as an example, the feasibility of the air curtain system is verified, and the jet angle of air curtain is optimized. The research results show that outside temperature and surrounding rock temperature are the main factors affecting the temperature field of tunnels in cold regions. The calculation results show that the air curtain system can effectively prevent tunnel freezing damage. The optimal jet angle of air curtain system should be 30°–40°. When the outside temperature is extremely low, multiple air curtains can be used in series to heat the temperature in the tunnel, and it is recommended that the distance between the two air curtains is not less than 20 m.

Dental anatomy education for dental technology students should be developed in alignment with digital dental laboratory practices. We hypothesized that a virtually assisted sketching-based dental anatomy teaching module could improve students' acquisition of skills essential for digital restoration design. The second-year dental technology curriculum included a novel virtual technology-assisted sketching-based module for dental anatomy education. Pre- and post-course assessments evaluated students' skill sets and knowledge bases. Computer-aided design (CAD) scores were analyzed after one year to assess how the skills students developed through this module impacted their subsequent CAD performance. Participants who undertook the dental sketching-based teaching module demonstrated significantly improved theoretical knowledge of dental anatomy, dental aesthetic perception, and spatial reasoning skills. A partial least squares structural equation model indicated that the positive effects of this module on subsequent CAD performance were indirectly mediated by dental aesthetic perception, spatial reasoning, and practice time. A virtually assisted sketching-based dental anatomy teaching module significantly improved students' acquisition of skills and knowledge and positively mediated dental technology students' CAD performance.

To explore the tendency of rockburst, a similar material ratio was optimised based on white sandstone. Quartz sand, iron powder, gypsum, cement, retarder, and a water-reducing agent were used as the main materials. The orthogonal test design principle was used to determine the four-factor and four-level orthogonal test design with the quartz sand content, iron powder content, gypsum-cement ratio, and sand particle size as the influencing factors. Uniaxial compression tests and tensile tests were conducted on similar material models. The tensile strength and elastic modulus were analysed, the significance of each influencing factor was investigated, and the test results of the similar materials were fitted. The optimal ratios of the similar materials of white sandstone were found to be quartz sand content of 36%, iron powder content of 1.9%, gypsum-cement ratio of 1.8 : 1, and sand particle size of 2–4 mm. The physical and mechanical properties of the similar materials were consistent with those of white sandstone. The mechanical properties of the similar materials were compared with those of the original rock. By judging the rockburst propensity and verifying the index, it is concluded that the similar materials can effectively simulate the characteristics of white sandstone, which is an ideal similar material of rockburst, and they all show strong rockburst propensity. The rock specimens with optimal proportions were produced, and the internal energy changes and rockburst mechanisms of the model at different temperatures were discussed. The results show that the rockburst process is closely related to energy, such as thermal energy and elastic strain energy, and the rock failure process can be divided into three main stages: energy accumulation, microcrack formation and propagation, and crack penetration and bursting. It provides an experimental basis for the preparation of rockburst similar materials that are more in line with the actual situation of the project and provides a basis for discussing the energy criterion of rockburst.