Theoretical study on the critical index of rock burst stress monitoring in coal seam drilling.

Rock burst disasters severely restrict the safe and efficient mining of coal. The fundamental cause of their occurrence is the concentration of stress within the coal mass. Stress monitoring in coal seam drilling is widely used as an effective method for rock burst monitoring. However, how to scientifically and reasonably set the critical values of early warning indicators that match the conditions of each mine has always been a key issue restricting the accurate prediction of rock burst by the drilling stress method. This paper adopts a method combining theoretical analysis and field practice to conduct research on the critical values of drilling stress early warning indicators. Based on perturbation response instability theory, a mechanical model for the occurrence of impact ground pressure has been established. Based on the instability theory of disturbance response, a mechanical model for the occurrence of impact ground pressure has been established, leading to the derivation of the expression for the near-field critical stress of impact ground pressure events. The theoretical formula for the critical value of drilling stress early warning indicators was obtained based on the difference between the critical stress of rock burst occurrence and the actual stress in the roadway. This formula includes the mechanical parameters of the coal mass and its propensity for rock burst, roadway support stress, mining depth, stress concentration coefficient, and the initial installation pressure of the stress gauge. They can be determined by the geological and mining technical conditions of each mine. This theoretical formula breaks the uniformity of the critical values for stress warning indicators in various mine drill holes, allowing each mine to scientifically determine its critical value based on its own conditions. This theoretical method has been applied to a high-stress mine in Shanxi, China, and the critical values of drilling stress early warning indicators were obtained. When the monitored stress exceeded the critical value, dynamic phenomena of anchor rod and cable fractures occurred in the roadway roof. The distribution of microseismic events also shifted towards the warning area, and the microseismic monitoring indicators reached the warning values. This confirmed the engineering feasibility of the critical values for drilling stress early warning indicators determined by the theoretical method.

One-Pot Biocatalytic Conversion of Chemically Inert Hydrocarbons into Chiral Amino Acids through Internal Cofactor and H2O2 Recycling.

Chemically inert hydrocarbons are the primary feedstocks used in the petrochemical industry and can be converted into more intricate and valuable chemicals. However, two major challenges impede this conversion process: selective activation of C-H bonds in hydrocarbons and systematic functionalization required to synthesize complex structures. To address these issues, we developed a multi-enzyme cascade conversion system based on internal cofactor and H2O2 recycling to achieve the one-pot deep conversion from heptane to chiral (S)-2-aminoheptanoic acid under mild conditions. First, a hydrogen-borrowing-cycle-based NADH regeneration method and H2O2in situ generation and consumption strategy were applied to realize selective C-H bond oxyfunctionalization, converting heptane into 2-hydroxyheptanoic acid. Integrating subsequent reductive amination driven by the second hydrogen-borrowing cycle, (S)-2-aminoheptanoic acid was finally accumulated at 4.57 mM with eep > 99%. Hexane, octane, 2-methylheptane, and butylbenzene were also successfully converted into the corresponding chiral amino acids with eep > 99%. Overall, the conversion system employed internal cofactor and H2O2 recycling, with O2 as the oxidant and ammonium as the amination reagent to fulfill the enzymatic conversion from chemically inert hydrocarbons into chiral amino acids under environmentally friendly conditions, which is a highly challenging transformation in traditional organic synthesis.

Construction of an S-scheme electron transfer channel in Cu0/CuFe2O4 magnetic plate column reactor for the LEV degradation: New strategy of visible Photo-Fenton system application.

The complicated loading process and easy falling off of powder catalysts still restrict the wide application of Photo-Fenton technology in practical water treatment. In this study, a magnetic fixed film plate column water treatment equipment is designed as a visible Photo-Fenton reactor to remove levofloxacin (LEV). The effect of magnetic force can ensure that the catalyst is firmly fixed, and the multi-level shallow column plate structure achieves full contact and efficient reaction between the catalyst and wastewater. Simultaneously, the Cu0/CuFe2O4 (STCCF) utilizes Cu0 to construct an S-scheme electron transfer channel, which improves the separation efficiency of photo-generated carriers and provides sufficient photo-generated electrons for the reduction of Fe (Ⅲ) and Cu (Ⅱ). The pseudo-first-order reaction kinetic constant k for the degradation of LEV in the visible Photo-Fenton system is 0.0349 min-1, which is 15.9 times that of the photocatalytic system and 4.8 times that of the Fenton system. After continuous operation for 72 h, the magnetic fixed film plate column reactor can still remove more than 90 % of LEV and 82 % of COD in the secondary effluent of simulated antibiotic pharmaceutical wastewater treatment process, and the effluent is stable and meets the standard. The magnetic fixed film plate column reactor can be used for advanced treatment of antibiotic pharmaceutical wastewater. This study provides a new insight into the application of the Photo-Fenton process.

Association between inflammatory biomarkers and hypertension among sedentary adults in US: NHANES 2009-2018.

Our study focuses on the relationship between inflammatory biomarkers and hypertension among sedentary adults in the United States, using data from the National Health and Nutrition Examination Survey (NHANES) from 2009 to 2018. We categorized 24,614 participants into two groups based on their daily sedentary time: 9607 individuals in the sedentary group (≥7 h) and 15,007 in the non-sedentary group (<7 h). We found that the sedentary group had a significantly higher prevalence of hypertension than the non-sedentary group. Using weighted multiple logistic regression and smoothing curves, we assessed the correlation between inflammatory biomarkers and hypertension among the sedentary adults. The odds ratios for hypertension were 1.92 for the monocyte to high-density lipoprotein ratio (MHR), 1.15 for the systemic inflammation response index (SIRI), and 1.19 for the natural logarithm of the systemic immune-inflammation index (lnSII), all showing nonlinear associations. Furthermore, a significant positive correlation was found between sedentary time and inflammatory biomarkers (MHR, SIRI, and lnSII). Our findings suggest that prolonged sedentary behavior in the US significantly increases hypertension risk, likely due to marked increases in inflammation markers.

Experimental Study on Carbon Dioxide Displacement by Coal Seam Water Injection.

Using water to displace carbon dioxide adsorbed in coal can prevent coal and gas outbursts. However, the mechanism of continuous water injection replacing adsorbed gases in coal has not been well studied. An experiment with the same water injection pressure and different adsorption equilibrium pressures for displacing carbon dioxide was conducted. The variation patterns of the amount of displaced carbon dioxide, time, and water displacement rate, displacement ratio, and water action ratio were analyzed. The modes of water injection displacing carbon dioxide are discussed. The results show that the change in the amount of displaced carbon dioxide consists of three stages: rapid, slow, and stop growth stages. For the same displacement time, as the adsorption equilibrium pressure rises, more carbon dioxide is displaced. The time displacement rate and water displacement rate can be divided into three stages: rising, peak, and dropping stages. As the adsorption equilibrium pressure increases, the duration of the peak stage decreases, while the time and water displacement rates increase. At different adsorption equilibrium pressures, the carbon dioxide displacement ratio ranged from 45% to 54%, less than the natural desorption ratio. But the water action ratio containing the gas dissolution amount was close to or greater than the natural desorption ratio. Thus, the displacement effect of flowing water accelerated the desorption of carbon dioxide in coal. The modes of carbon dioxide displacement by water injection include water-displacement, gas-dissolution displacement, and gas-diffusion-dissolution displacement. The findings of this study provide novel suggestions for preventing and controlling coal and gas outbursts.

Selective Phosphate Adsorption Using Topologically Regulated Binary-Defect Metal-Organic Frameworks: Essential Role of Interfacial Electron Mobility.

Metal-organic framework (MOF)-modified biochars (BC) have gained recognition as potent adsorbents for phosphate. However, essential insights into the electronic interfacial state of the MOFs remain lacking. In this study, we propose a novel topological transformation strategy to directionally regulate the interfacial electronic states of BC/MOFs composites. The optimized BC/MOFs exhibited an excellent selective phosphate adsorption capacity of 188.68 mg·g-1, coupled with rapid sorption kinetics of 6.81 mg·(g·min0.5)-1 in simulated P-laden wastewater. When challenged with real bioeffluent, such efficacy was still maintained (5 mg·L-1, 25.92 mg·g-1). This superior performance was due to the Fe(III) → Fe(II) transition, promoting electron mobility and leading to the anchoring of Mg(II) to form specific coordination unsaturated sites (Mg-CUS) for phosphate adsorption. Importantly, the simultaneous regulation of binary defects further enhances electron mobility, resulting in the formation of sp3 unequal hybrid orbitals with a stronger internal coupling capability between Mg 3s in Mg-CUS and O 2p in phosphate. Furthermore, the high electron affinity of Mg effectively promotes electron cycling, endowing BC/MOFs with a distinct self-healing capability to facilitate phosphate desorption. The outcomes of this study provide novel perspectives for electronic regulated phosphate adsorption.

Experimental study on the gas desorption law in coal affected by dynamic water injection.

Water from hydraulic technology affects the desorption of gas from coal seams. Gas desorption behavior is critical information for gas control in coal mines. In this study, a designed coal seam water injection simulation experimental device was utilized to conduct dynamic water injection experiments on coal samples at different adsorption equilibrium pressures, analyzing the gas desorption law under dynamic water injection, as well as the role of water replacement, water imbibition and water blockage in gas desorption. The results showed that water altered the gas desorption rate in coal, causing fluctuating attenuation of the desorption rate of a water-injected coal sample (WCS). Under the same adsorption equilibrium pressure, the relationship between the desorption rate of the WCS and the non-water-injected coal samples (NCS) underwent a transition in desorption time. In contrast to the NCS desorption curves, the WCS desorption curves lacked a rapid growth phase and exhibited only a slow growth phase and a stopping phase. Water imbibition and water replacement promoted the desorption of gas in the non-wet area during the water injection process, while it inhibited the desorption of gas in the wet area. Under the effects of water imbibition, water blockage, and water replacement, the discharge rate of WCS is greater than the desorption rate of NCS, indicating that water injection increases the total amount of gas desorption. The study results have significant implications for gas extraction and the prevention and control of coal and gas outbursts.

Enhanced and synergistic catalytic activation by photoexcitation driven S-scheme heterojunction hydrogel interface electric field.

The regulation of heterogeneous material properties to enhance the peroxymonosulfate (PMS) activation to degrade emerging organic pollutants remains a challenge. To solve this problem, we synthesize S-scheme heterojunction PBA/MoS2@chitosan hydrogel to achieve photoexcitation synergistic PMS activation. The constructed heterojunction photoexcited carriers undergo redox conversion with PMS through S-scheme transfer pathway driven by the directional interface electric field. Multiple synergistic pathways greatly enhance the reactive oxygen species generation, leading to a significant increase in doxycycline degradation rate. Meanwhile, the 3D polymer chain spatial structure of chitosan hydrogel is conducive to rapid PMS capture and electron transport in advanced oxidation process, reducing the use of transition metal activator and limiting the leaching of metal ions. There is reason to believe that the synergistic activation of PMS by S-scheme heterojunction regulated by photoexcitation will provide a new perspective for future material design and research on enhancing heterologous catalysis oxidation process.

Research on charge induction law and application of coal samples with different fissures.

Indoor testing are performed to explore the charge induction law during the uniaxial compression fracture process of coal samples, and the charge time and frequency domain signals of coal samples with different primary fissures are analyzed in the paper. On-site monitoring of charge in different fissures distribution areas of underground coal tunnels, and the charge signals of different drillingdepths in coal seams are analyzed. The results show that the uniaxial compressive strength and elastic modulus of multi-fissured coal samples are less than those of less fissured coal samples, and the Poisson's ratio is greater than those of less fissured coal samples. The charge induction signal intensity during the fracture process of multi-fissured coal samples is relatively low, but it is concentrated at the low frequency of 0-50 Hz in the compacting elasticity stage. The charge signal intensity during the fracture process of coal samples with less fissure is relatively high, and the charge frequency during the reinforcement damage stage is concentrated at a low frequency of 0-50 Hz. Therefore, the sudden appearance of low-frequency charge signals is more suitable as effective precursor information for the instability and failure of less fissured coal bodies. The average charge intensity is small in the multi-fissured area with a drilling depth of 1-4 m in the coal seam, and the average charge intensity of the coal body with less fissures is larger in the 5-12 m region. The on-site charge monitoring results have good consistency with the indoor test results. This study has guiding significance in setting up a charge monitoring warning index of instability failure in different coal body fissures regions.

Failure characteristics and conditions of rock-coal combination structure with weak layer under dynamic and static stresses.

To comprehensively understand the mechanical response of a rock-coal combination structure containing a weak layer, a series of laboratory static loading and impact loading experiments were conducted. The results showed that under static load, the sliding process of the rock coal structure was relatively slow, and fragments can be observed. Under the action of horizontal impact loading, the whole coal stratum slipped out rapidly, and the process lasted only 0.05 s. Under the horizontal and axial impact loads, the coal stratum remained stable first, and then it slipped out as a whole under the action of static load. Additionally, a sliding instability criterion of a rock coal structure containing a weak layer was established based on theoretical analysis. The key parameter P value was checked through a numerical simulation experiment. It was found that the value was linearly related to the mechanical properties of the weak layer and overburden stress, and the experimental results coincided with the theoretical results. Finally, the relationship between sliding rockburst and strain rockburst was discussed, and these results can provide an important scientific basis for the prevention and control of dynamic disasters in deep mining.

MADS-box protein AGL8 interacts with chromatin-remodelling component SWC4 to activate thermotolerance and environment-dependent immunity in pepper.

Pepper (Capsicum annuum) employs distinct defence responses against Ralstonia solanacearum infection (RSI); however, the mechanisms by which pepper activates these defence responses in a context-dependent manner is unclear. Here we study pepper plants defence response to RSI under room temperature-high humidity (RSRT, 28 °C / 90%) and high temperature-high humidity (RSHT, 37 °C / 90%) conditions, and non-infected plants under high temperature-high humidity (HTHH, 42 °C / 90%) stress. Herein, we found that the MADS-box transcription factor CaAGL8 was up-regulated by HTHH stress and RSRT or RSHT, and its silencing significantly reduced pepper thermotolerance and susceptibility to infection under both room and high temperature-high humidity (RSRT and RSHT). This was coupled with down-regulation of CaSTH2 and CaDEF1 upon RSRT, down-regulation of CaMgst3 and CaPRP1 upon RSHT, and down-regulation of CaHSP24 upon HTHH. In contrast, the ectopic overexpression of CaAGL8 significantly increased the resistance of Nicotiana benthamiana plants to RSRT, RSHT, and HTHH. In addition, CaAGL8 was found to interact with CaSWC4, which acted as a positive regulator of the pepper response to RSRT, RSHT, and HTHH. Silencing of either CaAGL8 or CaSWC4 blocked the hypersensitive response (HR) cell death and context-dependent up-regulation of defence-related genes triggered by the other. Importantly, enrichment of H4K5Ac, H3K9Ac, H3K4me3, and H3K9me2 on the tested defence-related genes was context- and gene-specifically regulated through synergistic interaction between CaSWC4 and CaAGL8. Our results indicate that pepper employs CaAGL8 to modulate chromatin remodelling by interacting with CaSWC4, thereby activating defence responses to RSRT, RSHT, and HTHH.

The Effect of Real-Time Tibial Acceleration Feedback on Running Biomechanics During Gait Retraining: A Systematic Review and Meta-Analysis.

OBJECTIVES: To explore the immediate and retention effect of real-time tibial acceleration feedback on running biomechanics during gait retraining. METHODS: Five electronic databases were searched to identify relevant studies published before May 2022. The included studies were evaluated for methodological quality and bias risk, and data were extracted. A meta-analysis was conducted on the primary outcomes, including peak tibial acceleration (PTA) and vertical ground reaction force. Subgroup analysis was performed by gender, feedback criterion, mode, dosage, fading, retention period, and running environment to evaluate the source of heterogeneity. Qualitative analysis was performed to describe other variables. RESULTS: Fourteen studies (174 participants) were eligible. Meta-analysis showed that real-time tibial acceleration feedback reduced PTA (P < .01, P < .01), vertical impact peak (P = .004, P < .01), vertical average loading rate (P < .01, P < .01), and vertical instantaneous loading rate (P < .01, P < .01) after feedback and during retention period (5 min-12 mo). Subgroup analysis showed that the immediate effect of vertical impact peak was more noticeable with mixed gender (P = .005) and fading feedback (P = .005) conditions, and the retention effect of PTA was more noticeable with high feedback dosage (P < .01) and fading feedback (P < .01) conditions. CONCLUSIONS: Real-time tibial acceleration feedback can reduce PTA and vertical ground reaction force during gait retraining, and for periods of 5 minutes to 12 months when the feedback is removed.

Interaction Between Obesity and Hypertension on Arteriosclerosis in Chinese Urban Adults: A Population-Based Cross-Sectional Study.

This study recruited 9,830 participants to identify whether the interaction between obesity and hypertension affects the occurrence of arteriosclerosis in Chinese adults. Brachial-ankle pulse wave velocity (baPWV) was measured to diagnose arteriosclerosis. Unconditional logistic regression was used for multiplicative interaction. The additive interaction was represented by relative excess risk due to interaction (RERI), attributable proportion (AP), and synergy (S). Hypertension was an independent risk factor for baPWV (p < .01), but obesity was not (p = .08). The interaction between obesity and hypertension on arteriosclerosis was not multiplicative (adjusted odds ratio = 0.89 (0.79-1.01), p = .07), but a negative additive interaction (RERI = -4.33, AP = -2.91, S = 0.10; p < .01) exists. Therefore, obesity may reduce the risk of arteriosclerosis caused by hypertension when hypertension and obesity coexist, especially in women and middle-aged people, which supports the obesity paradox.

Comparison of 10 obesity-related indices for predicting hypertension based on ROC analysis in Chinese adults.

Objective: To compare the predictive performance of the percentage body fat (PBF), body mass index (BMI), waist circumference (WC), hip circumference (HC), waist-hip ratio (WHR), waist-height ratio (WHtR), a body shape index (ABSI), body roundness index (BRI), abdominal volume index (AVI), and conicity index (CI) for identifying hypertension. Methods: A cross-sectional study was conducted among 2,801 adults (1,499 men and 1,302 women) aged 18 to 81 in Ningbo, China. The receiver operator characteristic (ROC) analysis and multiple non-parametric Z tests were used to compare the areas under the curve (AUC). The maximum Youden's indices were used to determine the optimal cut-off points of 10 obesity-related indices (ORI) for hypertension risk. Results: The AUC of all the indices were statistically significant (P < 0.05). The AUC of all the indices in men and women were 0.67-0.73 and 0.72-0.79, respectively. Further non-parametric Z tests showed that WHR had the highest AUC values in both men [0.73 (95% CI: 0.70, 0.76)] and women (0.79 (95% CI: 0.75, 0.83)], and several central ORI (men: WHR, WC, BRI, AVI, and CI, 0.71-0.73; women: WC, WHR, and AVI, 0.77-0.79) were higher than general ORI (PBF and BMI, 0.68 in men; 0.72-0.75 in women), with adjusted P < 0.05. The optimal cut-off points for identifying hypertension in men and women were as follows: PBF (23.55%, 32.55%), BMI (25.72 kg/m2, 23.46 kg/m2), HC (97.59 cm, 94.82 cm), WC (90.26 cm, 82.78 cm), WHR (0.91, 0.88), WHtR (0.51, 0.55), ABSI (0.08 m7/6/kg2/3, 0.08 m7/6/kg2/3), BRI (4.05, 4.32), AVI (16.31 cm2, 13.83 cm2), and CI (1.23 m2/3/kg1/2, 1.27 m2/3/kg1/2). Multivariate logistic regression models showed that all indices were statistically significant (P < 0.05) with the adjusted ORs (per 1-SD increase) at 1.39-2.06 and ORs (over the optimal cut-off points) at 1.80-2.64. Conclusions: All 10 ORI (PBF, BMI, HC, WC, WHR, WHtR, ABSI, BRI, AVI, and CI) can effectively predict hypertension, among which WHR should be recommended as the best predictor. Central ORI (WHR, WC, and AVI) had a better predictive performance than general ORIs (PBF and BMI) when predicting the risk of hypertension.

Comparison of Five Expressions of Handgrip Strength for Predicting Cardiovascular Disease Risk Factors in Chinese Middle-Aged Community Residents.

Objective: To compare the predictive performance of five handgrip strengths for cardiovascular disease (CVD) risk factors. Methods: A total of 804 Chinese middle-aged community residents' health medical examinations were collected. The absolute handgrip strength was denoted as HGS. HGS/body weight (HGS/BW), HGS/body mass index (HGS/BMI), HGS/lean body mass (HGS/LBM), and HGS/muscle mass (HGS/MM) represented relative handgrip strength (RHGS). To assess predictive performance, receiver operating characteristic (ROC) curves and the area under the curve (AUC) were constructed. Results: HGS was not associated with most CVD risk biomarkers; however, RHGS showed a negative correlation trend after controlling for covariates (sex, age, smoking, and exercise). HGS/BMI and HGS/BW had better AUCs for predicting CVD risk factors than HGS/LBM or HGS/MM. HGS/BMI and HGS/BW can successfully predict all CVD risk factors in men with AUCs 0.55-0.65; similarly, women may effectively predict arteriosclerosis, hyperglycemia, hyperuricemia, and metabolic syndrome with AUCs 0.59-0.64, all p < 0.05. The optimal HGS/BW cut-off points for identifying different CVD risk factors were 0.59-0.61 in men and 0.41-0.45 in women, while the HGS/BMI were 1.75-1.79 in men and 1.11-1.15 in women. Conclusions: Almost all CVD risk biomarkers and CVD risk factors were unrelated to HGS. There is, however, a significant inverse relationship between RHGS and CVD risk factors. HGS/BMI or HGS/BW should be recommended to be the best choice for predicting the risk of CVD risk factors in five expressions of handgrip strength. We also acquired the recommended optimal cut-off points of HGS/BMI and HGS/BW for predicting CVD risk factors.

Burnout and resilience among pharmacy technicians: A Singapore study.

BACKGROUND: Burnout describes emotional exhaustion (EE), depersonalization (DP), and low personal achievement caused by work and is known to bring about negative consequences to practitioners, patients, and health systems. Various organizational and personal factors, such as organizational strategies and resilience, have been associated with this phenomenon. However, there is a paucity of data describing the prevalence of burnout among pharmacy staff within Singapore and Asia, especially in the pharmacy technician (PT) population. OBJECTIVES: This study aimed to (1) quantify burnout in PTs in patient-care sectors in Singapore and (2) explore factors that may be associated with burnout. METHODS: A cross-sectional survey among PTs in patient-care areas in Singapore, which includes hospitals, primary and secondary care institutions, and retail pharmacies, across both public and private sectors was conducted from February to April 2020. The Maslach Burnout Inventory - Human Services Survey and Brief Resilience Scale were used to assess burnout and resilience among participants. Demographic, employment, and well-being information were also collected and summarized. Univariate analysis and multivariate logistic regression were used to assess associations between burnout and potential risk and impact factors. RESULTS: Slightly more than half (52.0%) of PTs reported burnout (EE score ≥27 or DP ≥10 or both). Statistically significant factors associated with burnout include resilience, age, years of experience, ethnicity, marital status, nationality, highest qualifications, pharmacy-related certification, full-time employment status, and work hours. Impact associated with burnout includes intent for job change, job satisfaction, sleep, and presence of mental conditions. Statistically significant reported reasons for burnout and ways to build resilience were also elucidated. CONCLUSION: Burnout affects most PTs in Singapore and is primarily driven by workload and nature of their work, low resilience, and poor social support structures. National and organizational efforts are needed to arrest the vicious cycle that propagates burnout in PTs.

MOF-derived N-doped ZnO carbon skeleton@hierarchical Bi2MoO6 S-scheme heterojunction for photodegradation of SMX: Mechanism, pathways and DFT calculation.

Semiconductor photocatalytic degradation of pollutants is considered to be one of the promising sustainable energy routes. Nevertheless, it is challenging for photocatalysts to have excellent visible light absorption and suppress photo-generated electron-hole recombination at the same time. Here, we prepared nitrogen-doped ZnO carbon skeleton by directly calcining the metal-organic framework. Then hierarchical Bi2MoO6 nanosheets are grown in situ on its surface to synthesize S-scheme heterojunction. This special 3D layered and oxygen vacancies work together to make photo-generated electrons and holes easier to separate and migrate. Therefore, the pseudo-first-order kinetic constant of N-doped ZnO carbon skeleton@Bi2MoO6 degradation of sulfamethoxazole reaches 0.022 min-1, which is almost 10 times that of ZIF-8 derived ZnO and 27.5 times Bi2MoO6 under visible light irradiation. Meanwhile, the mechanism of driving charge transfer of S-scheme heterojunction, and the photocatalytic degradation pathway of sulfamethoxazole are also analyzed. This work will provide a new way to construct S-scheme heterojunction photocatalyst to degrade antibiotic pollutants.

Effects of Video Task With a High-Level Exercise Illustration on Knee Movements in Male Volleyball Spike Jump.

Hazardous knee biomechanics, such as excessive knee affordance link with injuries in volleyball spike jumps (SPJs) and can be reconfigured by the enhancement of internal focus. The study aimed to explore the effects of video tasks illustrating a high-level SPJ on knee movement in the volleyball SPJ with 15 elite male volleyball athletes. This study investigated the knee movements in sagittal, coronal, and transverse planes before and after the video task in SPJ using one-dimensional statistical parametric mapping (SPM 1D) and discrete statistics. The SPM 1D indicated a larger knee flexion angle (31.17-73.19%, t = 2.611, and p = 0.012), increased knee flexion moment (19.72-21.38%, t = 0.029, and p = 0.029), and increased knee adduction angular velocity (49.07-62.64%, t = 3.148, and p = 0.004) after video task; alternatively, smaller knee external rotation angular velocity (45.85-49.96%, t = 5.199, and p = 0.017) and vertical ground reaction (vGRF) (3.13-5.94%, t = 4.096, and p = 0.014; 19.83-21.97%, t = 4.096, and p = 0.024) were found after the task. With discrete value statistics, the video task increased the peak of knee flexion angle while decreased the peak of extension moment, flexion moment, abduction moment, external moment, the first peak vGRF, and related loading rate. Conclusions: The results indicate that knee biomechanics in volleyball SPJ positively influenced by the video task. The task has the athletes control the knee movements more actively and improves the original hazardous movement strategies. Therefore, the video task presumably can abate the occurrence of knee injuries in volleyball SPJ. Further validation especially in the exercise effect is needed in the future.

Predictive Performance and Optimal Cut-Off Points of Blood Pressure for Identifying Arteriosclerosis among Adults in Eastern China.

This study aimed to assess the predictive performance and establish optimal cut-off points of blood pressure for identifying arteriosclerosis in eastern Chinese adults. Brachial-ankle pulse wave velocity (baPWV) was utilized to evaluate arteriosclerosis. The predictive performance of blood pressure for arteriosclerosis was determined by the area under the curve (AUC) of receiver operating characteristics; the optimal blood pressure cut-off points were determined by Youden's index. A logistic regression model was used to acquire the odds ratio (OR) of blood pressure for arteriosclerosis. The AUCs of blood pressure for identifying arteriosclerosis were 0.868 (95%CI: 0.860-0.875) for systolic blood pressure (SBP) and 0.835 (95%CI: 0.827-0.843) for diastolic blood pressure (DBP), both p < 0.01. The AUCs of women were higher than that of men (0.903 vs. 0.819 for SBP; 0.847 vs. 0.806 for DBP; Z test p < 0.05). The AUCs in the 18-39.9-years group were higher than that in the 40-59.9-years and 60-84-years groups (0.894 vs. 0.842 and 0.818 for SBP; 0.889 vs. 0.818 and 0.759 for DBP; Z test p < 0.05). The total optimal cut-off points of blood pressure for predicting arteriosclerosis were 123.5/73.5 mmHg (SBP/DBP) overall; 123.5/73.5 and 126.5/79.5 mmHg for women and men, respectively; and 120.5/73.5, 123.5/76.5, and 126.5/75.5 mmHg for 18-39.9-years, 40-59.9-years, and 60-84-years groups, respectively. Blood pressure indexes had a high predictive performance for identifying arteriosclerosis with the optimal cut-off point of 123.5/73.5 mmHg (SBP/DBP) in eastern Chinese adults. Women or the younger population have a higher predictive performance and lower cut-off points to identify arteriosclerosis.

Impact of the COVID-19 Pandemic on the Mental Health of College Students: A Systematic Review and Meta-Analysis.

BACKGROUND: The coronavirus disease (COVID-19) pandemic has been spreading and brought unprecedented psychological pressure on people across the entire globe since December 2019. OBJECTIVES: To synthesize the existing evidence of the prevalence of mental health status during the epidemic and provide the basis for mental health education. MATERIALS AND METHODS: The literature search was conducted in nine databases from December 2019 to October 2020. The risk of bias for each study was assessed, and the random-effects meta-analysis was used to estimate the prevalence of specific mental health problems. The review protocol was registered in PROSPERO with the registration number CRD42020208619. RESULTS: About 27 studies were included in the analysis with a total of 706,415 participants combined, and 14 mental health problems were gathered. Meta-analysis showed that the prevalence of depression was 39% (95% CI: 27-51%) and that of anxiety was 36% (95% CI: 26-46%). Subgroup analysis indicated that the prevalence of depression and anxiety varied among nations and due to the survey date. The prevalence of depression (60%, 95% CI: 46-74%) and anxiety (60%, 95% CI: 46-74%) in non-Chinese college students was higher than those in Chinese college students (26%, 95% CI: 21-30% and 20%, 95% CI: 14-26%). The proportion of depression (54%, 95% CI: 40-67%) and anxiety (37%, 95% CI: 26-48%) was higher after March 1 than before it (21%, 95% CI: 16-25% and 19%, 95% CI: 13-25%). CONCLUSIONS: The meta-analysis results presented that the prevalence of depression (39%) or anxiety (36%) among college students greatly increased during the COVID-19 pandemic. In addition, the mental health of college students is affected by the nations and the survey date. It was necessary to take measures to reduce mental health risks during the pandemic.