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Objective Water inrush in karst tunnel has a great influence on tunnel safety. Methods Taking the Wufeng Tunnel of Yilai Expressway as the research object, the risk of water inrush in the tunnel was identified though field hydrogeological investigation, borehole water level and indoor rainfall monitoring, numerical simulation and small-scale model tests. Results The test results show that the risk of water inrush in the tunnel is mainly affected by the relative spatial position between the karst pipeline and tunnel, including the water pressure of the pipeline. The influence of seepage on the tunnel can be effectively reduced by increasing the thickness of the overlying soil when the test water pressure is 0.2 MPa. But with the increase in water pressure, the seepage of pipeline water is not only vertical seepage but also includes horizontal seepage. The intermittent cracks in the waterproof layer expand, which finally results in water inrush damage in the tunnel. The numerical simulation results show that the maximum shear force of the Wufeng Tunnel is at the arc and shoulder, which may easily form tensile shear failure along this part under groundwater seepage. The finding is consistent with the test results of the small-scale model. The water inrush in the tunnel is the coupling effect of the shear force and seepage field. Conclusion The primary factor of water inrush in the tunnel is water pressure and is closely related to the thickness of water barrier rock.

Objective The dry-wet cycles can promote the deterioration of the mechanical properties and stability of schist slope rock masses and induce geological disasters such as landslides and collapses. Methods Taking mica quartz schist, which is widely distributed in Shiyan, Hubei Province, as the research object, uniaxial compression tests and electron microscope scanning were carried out on mica quartz schist samples under different dry-wet cycles to reveal the degradation law and mechanism of its compressive property. Results The results show that under the action of dry-wet cycles, the degradation effect of the compressive strength and elastic modulus of mica quartz schist were obvious. The degradation rate was fast and the degradation range was large in the early stage, but the degradation rate was slow and the degradation range was low in the later stage. The macroscopic failure modes were gradually controlled by the schistosity planes, which gradually evolved from styles of "X" and "Y" failure to along the schistosity planes failure. The microstructure was characterized by continuous spalling and granulation of flake mineral particles, and the microcracks as well as pores were gradually developed, expanded and connected. The mica quartz schist produces secondary minerals, ions and rock cuttings and leaves the rock continuously under dry-wet cycles, which promotes the preferential expansion and cracking of schistosity, microcracks and other structural planes. which then degrades the overall mechanical properties of the mica quartz schist. Conclusion The research results can provide a theoretical basis for the stability analysis and treatment design of schist slopes.

Dataspace is the transformation of cyberspace from ＆quot;computing centric＆quot; to ＆quot;data centric＆quot;, which contains great technological issues and innovative opportunities.Similar to the internet, which is the main infrastructure of cyberspace, dataspace also needs a new ＆quot;data-centric＆quot; infrastructure, whose core function is to realize the first-class entity of data.From the perspective of dataspace, the supports and shortcomings of mainstream technologies such as the internet, the World Wide Web, and the digital object architecture for the first-class entity of data were analyzed and summarized, and then the basic connotations and technical challenges of dataspace infrastructure were given.Finally, a first-class data substantialization method based on data pragmatics was proposed.Based on this method, a solution called the internet of data by integrating digital object architecture, distributed ledger, smart contract, and other technologies was proposed to support the construction and operation of internetscale dataspace infrastructure.

OBJECTIVES The purpose of this study was to investigate the effects of assist and resistance torque on the spatiotemporal gait characteristics, and the symmetry and asymmetry of gait using a Gait Enhancing and Motivating System (GEMS) in the elderly. METHODS A cross-sectional and repeated measure design was used. A total of 18 participants (9 males, 9 females; age: 63.5 ± 5.02 years; mass: 64.26 ± 6.87 kg; height: 164.06 ± 7.15 cm) were recruited from a local community, and spatiotemporal gait data were collected with OptoGait system and GEMS. Spatiotemporal gait variables and differences between the dominant and non-dominant legs of these variables were assessed (step length, step time, stance phase, swing phase, single support, load response, pre swing phase, stride time, stride length, double support, cadence, and gait speed). The effects of three modes including normal, assist, and resist modes using GEMS were investigated twice for each participant on a 9-meter walkway. A one-way repeated measure analysis of variance followed by Bonferroni post-hoc tests was conducted. RESULTS The assist mode increased step time, swing phase, stride time and reduced stance phase, pre-swing phase, double support, cadence, and gait speed as compared to normal mode. The resist mode increased stance phase, load response, pre-swing phase, double support, cadence, and reduced step time, swing phase, and stride time. In dominant leg, assist mode showed increased step time and reduced pre-swing phase than normal mode, and greater step time than resist mode (p < 0.05). However, there was no effect of external torque on symmetry and asymmetry between both legs (p > 0.05). CONCLUSIONS The resistance and assist torque of GEMS alter spatiotemporal characteristics during the stance and swing phase of gait in the elderly. However, the resistance torque and assist torque of GEMS did not increase or decrease the gait asymmetry between the dominant and non-dominant legs.

The multi-round sequential memory coal drawing technology can improve the recovery rate of top coal and gangue content in the fully mechanized working face. But it needs to accurately measure and control the time of each round of coal drawing in field application. In the practical application of the automatic coal drawing technology based on the top coal migration tracker, the top coal movement tracker is only used as a mark point and is arranged in the top coal. The top coal movement tracker can not obtain more top coal movement information. In view of the above problems, based on the top coal movement tracker, a top coal migration time measurement system based on accelerometer is designed. The system includes three parts: tag, collector and central computer. The label is placed inside the top coal, and moves along with the top coal in the coal drawing process. Through the built-in accelerometer, the specific force data is collected in real-time. The time measurement algorithm is called to realize the monitoring of top coal migration. Then the different coal drawing stages are determined. The top coal migration time information of different stages is calculated. When the tag is released from the coal chute, it collides with the scraper conveyor belt, and sends the top coal migration time information outward to the collector through the RF signal. The information is further transmitted to the central computer through the field bus to guide the fully mechanized working face to realize multi-round of sequential coal drawing on site. The hardware and software design of the time measurement label of top coal migration is introduced in detail. The functions of real-time acquisition of specific force value, wireless signal transmission and data storage are realized. A calibration platform with 3D turntable as the core and Gauss-Newton method as the calibration algorithm is built. The calibration of the accelerometer is completed. The calibrated accelerometer can accurately collect the specific force data of the top coal migration time measurement label. According to the migration characteristics of top coal in the process of coal drawing, the time measurement algorithm based on threshold and the time measurement algorithm based on long-term and short-term memory (LSTM) are proposed. The time measurement algorithm based on threshold realizes the time identification of motion stage by introducing static threshold and maximum threshold. The time measurement algorithm based on LSTM identifies the dynamic changes of the specific force vector sum in the time domain, finds the mutation point, and realizes the time identification of the motion stage. The performance test of the two time measurement algorithms is completed through the tag free falling experiment. The time measurement variance is 0.000 6 and 0.000 2 respectively. The time measurement error is 13.07% and 5.22% respectively. The results meet the on-site top coal migration time measurement requirements. And the time measurement algorithm based on LSTM has obvious application advantages in top coal migration time measurement.

In order to study the effects of freezing-thawing times on the quality characteristics of frozen mutton. After freezing and thawing repeatedly for 0, 1, 3, 5 times and then refrigerated at 4 ℃ for 1, 3, 5, 7 days, the nutritional quality, edible quality, texture characteristics and lipid oxidation degree of Oula Tibetan mutton were determined. The results showed that with the increase of freeze-thaw times, the nutritional quality of Tibetan mutton deteriorated significantly, the moisture content and protein content decreased significantly (P < 0.05); The overall eating quality of Tibetan mutton decreased significantly, especially after 5 freeze-thaw cycles, the color stability and water holding capacity decreased significantly (P < 0.05), the tenderness decreased slightly, but the change was not significant, and the meat hardness and chewiness decreased, while the viscosity, elasticity and adhesiveness increased; Meanwhile, peroxide value (POV) and thiobarbituric acid value (TBARS) reached the maximum after 5 freeze-thaw cycles (P < 0.05), indicating that the degree of lipid oxidation increased with the increase of freeze-thaw cycles; At the same time, the longer the cold storage time, the worse the meat quality. The above results showed that the increase of freeze-thaw cycles had a great impact on the meat quality, and the repeated freeze-thaw phenomenon should be avoided in the actual production, processing and transportation of meat.

The combination of the curtain and pit dewatering is the main trend of groundwater control in the deep foundation pit project.Due to the complexity and scale effect of the seepage field around the deep foundation pit, there is still no mature and accurate analytical calculation method for dewatering design.Based on the comparison of the characteristics of the seepage field between the suspended curtain and the gate dam, a new subsection mode of seepage section of suspended curtain foundation pit under confined aquifer is proposed.Modified from the improved resistance coefficient method of the gate dam, a new formula for calculating equivalent resistance coefficient of "horizontal confluence section"within special zone of foundation pit is derived, which is extended to the anisotropic condition of aquifer and can be used in the quantitative calculation of the water outflow and drawdown in the suspended curtain foundation pit.Finally, the accuracy of the method is verified by numerical simulation combined with a typical foundation pit case.The studies show that, after reasonable segmentation, equivalence and correction, the relative error between the improved resistance coefficient method and the numerical modeling can be controlled within 5%, with high accuracy.Besides, it has the advantages of flexible segmentation and simple calculation, and can be applied to the calculation of foundation pit dewatering design under different site conditions.

Objective The rapid yeast and mold count plate (RYM) method and the national standard (GB 4789.15-2016) method were compared for the consistency in three types of food detection. Methods 90 pastry, bread and biscuits samples, 30 milk beverage, vegetable protein beverage and solid drink samples, 30 health foods samples, three types of artificially contaminated food samples were detected by the RYM method and the GB method, then the data of the two method were analyzed by the paired t test and the log difference (| dlog |). Results The statistics were made for the data of three types of food samples and three types of artificially contaminated food samples. The paired t test gave P>0.05, and the ratio of |dlog| ≤0.50 were 100.0%. There was no significant difference between the result of the two method. Conclusion There is no significant difference between the results of the RYM method and the GB method in detecting three types of food samples and three types of artificially contaminated food samples.

Take the background of hard roof support problem of Qiuji Coal Mine 1102 working face haulageway, the cantilever beam model of uncutting roadway roof and the deformation and stress model of gob-side entry retaining are established. The maximum cantilever length of roadway roof cantilever beam structure is 4.68 m by theoretical calculation; the support resistance of the roadway roof with unit length suspended is 166.74 kN. Based on this, the parameters of roadway are designed, the specification of constant resistance and large deformation anchor cable is determined as ?准17.8 mm × 10 300 mm, and the spacing of two columns of anchor cable to be 1 000 mm and 2 000 mm respectively, and the roadway mine pressure is monitored. Monitoring results show that: within the range of 75 m to 173 m from the open-cut hole in 1102 haulageway, the maximum displacement of roadway roof and floor is about 36 mm, the roof abscission layer occurs at the junction of mudstone and limestone, the accumulative amount of abscission layer amount is 25 mm, the maximum stress of roof anchor cable is 150 kN, both deformation and stress are within a safe range, meet the stability requirement of roadway.

Objective: To evaluate the prognostic value of left ventricular ejection fraction (LVEF) reserve assessed by gated SPECT myocardial perfusion imaging (SPECT G-MPI) for major adverse cardiovascular event (MACE) in patients with coronary artery disease. Methods: This is a retrospective cohort study. From January 2017 to December 2019, patients with coronary artery disease and confirmed myocardial ischemia by stress and rest SPECT G-MPI, and underwent coronary angiography within 3 months were enrolled. The sum stress score (SSS) and sum resting score (SRS) were analyzed by the standard 17-segment model, and the sum difference score (SDS, SDS=SSS-SRS) was calculated. The LVEF at stress and rest were analyzed by 4DM software. The LVEF reserve (ΔLVEF) was calculated (ΔLVEF=stress LVEF-rest LVEF). The primary endpoint was MACE, which was obtained by reviewing the medical record system or by telephone follow-up once every twelve months. Patients were divided into MACE-free and MACE groups. Spearman correlation analysis was used to analyze the correlation between ΔLVEF and all MPI parameters. Cox regression analysis was used to analyze the independent factors of MACE, and the optimal SDS cutoff value for predicting MACE was determined by receiver operating characteristic curve (ROC). Kaplan-Meier survival curves were plotted to compare the difference in the incidence of MACE between different SDS groups and different ΔLVEF groups. Results: A total of 164 patients with coronary artery disease [120 male; age (58.6±10.7) years] were included. The average follow-up time was (26.5±10.4) months, and a total of 30 MACE were recorded during follow-up. Multivariate Cox regression analysis showed that SDS ( HR =1.069, 95% CI : 1.005-1.137, P =0.035) and ΔLVEF ( HR =0.935, 95% CI : 0.878-0.995, P =0.034) were independent predictors of MACE. According to ROC curve analysis, the optimal cut-off to predict MACE was a SDS of 5.5 with an area under the curve of 0.63 ( P =0.022). Survival analysis showed that the incidence of MACE was significantly higher in the SDS≥5.5 group than in the SDS<5.5 group (27.6% vs. 13.2%, P =0.019), but the incidence of MACE was significantly lower in the ΔLVEF≥0 group than in theΔLVEF<0 group (11.0% vs. 25.6%, P =0.022). Conclusions: LVEF reserve (ΔLVEF) assessed by SPECT G-MPI serves as an independent protective factor for MACE, while SDS is an independent risk predictor in patients with coronary artery disease. SPECT G-MPI is valuable for risk stratification by assessing myocardial ischemia and LVEF.

Objective: To evaluate the predictive value of the proportion of hibernating myocardium (HM) in total perfusion defect (TPD) on reverse left ventricle remodeling (RR) after coronary artery bypass graft (CABG) in patients with heart failure with reduced ejection fraction (HFrEF) by 99m Tc-methoxyisobutylisonitrile (MIBI) single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) combined with 18 F-flurodeoxyglucose (FDG) gated myocardial imaging positron emission computed tomography (PET). Methods: Inpatients diagnosed with HFrEF at the Cardiac Surgery Center, Anzhen Hospital of Capital Medical University from January 2016 to January 2022 were prospectively recruited. MPI combined with 18 F-FDG gated PET was performed before surgery for viability assessment and the patients received follow-up MPI and 18 F-FDG gated PET at different stages (3-12 months) after surgery. Δ indicated changes (post-pre). Left ventricular end-systolic volume (ESV) reduced at least 10% was defined as RR, patients were divided into reverse remodeling (RR+) group and the non-reverse group (RR-). Binary logistic regression analysis was used to identify predictors of RR. Receiver operating characteristic (ROC) curve analysis was performed and the area under the curve (AUC) was calculated to assess the cut-off value for predicting RR. Additionally, we retrospectively enrolled inpatients with HFrEF at the Cardiac Surgery Center, Anzhen Hospital of Capital Medical University from January 2021 to January 2022 as the validation group, who underwent MPI and 18 F-FDG gated PET before surgery. Echocardiography was performed before CABG and after CABG (3-12 months). In the validation group, the reliability of obtaining the cut-off value for the ROC curve was verified. Results: A total of 28 patients with HFrEF (26 males; age (56.9±8.7) years) were included in the prospective cohort. HM/TPD was significantly higher in the RR+ group than in the RR- group ((51.8%±17.9%) vs . (35.7%±13.9%), P =0.016). Binary logistic regression analysis revealed that HM/TPD was an independent predictor of RR (Odds ratio=1.073, 95% Confidence interval: 1.005-1.145, P =0.035). ROC curve analysis revealed that HM/TPD=38.3% yielded the highest sensitivity, specificity, and accuracy (all 75%) for predicting RR and the AUC was 0.786 ( P =0.011). Meanwhile, a total of 100 patients with HFrEF (90 males; age (59.7±9.6) years) were included in the validation group. In the validation group, HM/TPD=38.3% predicted RR in HFrEF patients after CABG with the highest sensitivity, specificity and accuracy (82%, 60% and 73% respectively). Compared with the HFrEF patients in the HM/TPD<38.3% group ( n =36), RR and cardiac function improved more significantly in the HM/TPD≥38.3% group ( n =64) (all P <0.05). Conclusions: Preoperative HM/TPD ratio is an independent factor for predicting RR in patients with HFrEF after CABG, and HM/TPD≥38.3% can accurately predict RR and the improvement of cardiac function after CABG.

Objective: To evaluate the relationship between the brain glucose metabolism and left ventricular function parameters, and to explore the cerebral glucose metabolism reduction regions in patients with ischemic heart disease (IHD). Methods: A total of 110 consecutive IHD patients who underwent gated (99)Tc(m)-sestamibi (MIBI) SPECT/CT myocardial perfusion imaging, gated (18)F-fluorodeoxyglucose (FDG) PET/CT myocardial and brain glucose metabolic imaging within three days in Beijing Anzhen Hospital from April 2016 to October 2017, were enrolled in this study. Left ventricular functional parameters of SPECT/CT and PET/CT including end-diastolic volume (EDV), end-systolic volume (ESV) and left ventricular ejection fraction (LVEF) were analyzed by QGS software. Viable myocardium and myocardial infarction region were determined by 17-segment and 5 score system, and the ratio of viable myocardium and scar myocardium was calculated. According to the range of viable myocardium, the patients were divided into viable myocardium<10% group (n=44), viable myocardium 10%-<20% group ( n =36) and viable myocardium≥20% group ( n =30). Pearson correlation analysis was used to analyze the correlation between the range of viable myocardium and scar myocardium and the level of cerebral glucose metabolism. Brain glucose metabolism determined by the mean of standardized uptake value (SUV(mean)) was analyzed by SPM. The ratio of SUV(mean) in whole brain and SUV(mean) in cerebellum were calculated, namely taget/background ratio (TBR). Differences in cerebral glucose metabolism among various groups were analyzed by SPM. Results: There were 101 males, and age was (57±10) years in this cohort. The extent of viable myocardium and the extent of scar, LVEF evaluated by SPECT/CT and PET/CT were significantly correlated with TBR ( r =0.280, r =-0.329, r =0.188, r =0.215 respectively,all P <0.05). TBR value was significantly lower in viable myocardium<10% group, compared with viable myocardium 10%-<20% group (1.25±0.97 vs. 1.32±0.17, P <0.05) and viable myocardium≥20% group (1.25±0.97 vs. 1.34±0.16, P <0.05). Furthermore, in comparison with viable myocardium≥20% group, the hypo-metabolic regions of viable myocardium<10% group were located in the precuneus, frontal lobe, postcentral gyrus, parietal lobe, temporal lobe, and so on. Conclusions: There is a correlation between impaired left ventricular function and brain glucose metabolism in IHD patients. In IHD patients with low myocardial viability, the level of glucose metabolism in the whole brain is decreased, especially in the brain functional areas related to cognitive function.

Positron emission tomography (PET) has become basic support equipment in clinical and many other scientific research fields and has been a hot research field at present. Tomography reconstruction algorithm is a key component of PET, and most PETs use statistical iterative reconstruction algorithms from sinograms data currently. However, tomography reconstruction from list-mode data possesses many unique advantages, and it has caused great attention and is in the process of rapid development and improvementin recently. We eventually achieved list-mode tomography reconstruction in this paper, using experimental data of small animal PET scanner Eplus-166, exploiting S-LMEM algorithm and orthogonal distance-based ray-tracer. The results demonstrated that image resolution and contrast recovery achieved inherent properties of the scanner and on-the-fly ray-tracing methods is feasible for dynamic reconstruction.

Objective: To study the effect of radiofrequency treatment of ethmoidal nerve on allergic rhinitis., Method: Eighty-eight cases of allergic rhinitis were treated with ethmoidal nerve radiofrequency under nasal endoscopy., Result: It showed marked effectiveness in 73 cases (83.0%), immprovement in 11 cases (12.5%) and failed in 4 cases (4.5%) in one year follow-up. The overall effective rate was 95.5%., Conclusion: This result indicated that it is a choice for treating allergic rhinitis to apply ethmoidal nerve radiofrequency under nasal endoscopy.