BACKGROUND： Inflammatory reaction and the increased level of its accompanying active protein play an important role in the occurrence and development of cerebral infarction. C-reactive protein, fibrinogen and white b...BACKGROUND： Inflammatory reaction and the increased level of its accompanying active protein play an important role in the occurrence and development of cerebral infarction. C-reactive protein, fibrinogen and white blood cell, as the monitoring index of inflammatory reaction, are very important in the occurrence and development of acute cerebral infarction. OBJECTIVE： To make a comparison between patients with primary hypertension accompanied with acute cerebral infarction and with simple primary hypertension by observing the changes in plasma C-reactive protein and fibrinogen levels as well as white blood cell and differential counts and analyzing their significances. DESIGN ： Controlled observation SETTING ： Ward Building for VIP, Shenzhen Hospital, Peking University. PARTICIPANTS： Totally 133 patients with primary hypertension were selected from Ward Building for VIP, Shenzhen Hospital, Peking University during September 2003 to September 2005, The diagnostic criteria were based on the hypertension diagnosis criteria formulated by the 7^th World Health Organization-International Society of Hypertension Guidelines （WHO-ISH） in 1998. The informed consents were obtained from all the participants. The involved patients were assigned into two groups： primary hypertension group, in which, there were 65 patients with primary hypertension （ degree 2）, including 42 males and 23 females, with mean age of （61 ±14）years and mean blood pressure of （162.7±6.8）/（94.2±8.4） mm Hg （1 mm Hg =0.133 kPa）, and primary hypertension combined with cerebral infarction group, in which, there were 68 patients with primary hypertension combined with cerebral infarction （ meeting the diagnostic criteria formulated in the 4^th National Cerebrovascular Diseases Meeting in 1995 and diagnosed by skull CT or MRI to exclude the patients with lacunar infarction）, including 42 males and 26 females, with mean age of （56±15） years and mean blood pressure of （176.4±9.2）/（96.3±9.7） mm Hg. METHODS： Plasm C-reactive protein and fibrinogen levels, and white blood cell and differential counts of patients in the two groups were examined 24 hours after stroke. The above indexes were re-examined in the primary hypertension combined with cerebral infarction group 72 hours after stroke. White blood cell and differential counts were performed with laser method （East Asia FE-95001 RAM-1, Japan）. The level of C-reactive protein was measured with turbidimetry （BNII Automatic Systems For Analysis, USA）. The level of fibrinogen was measured with algorithm method when prothrombin time was normal and with Clauss method when prothrombin time was abnormal （ACL Automatic Coagulation Analyzer, USA）. MAIN OUTCOME MEASURES： The plasm C-reactive protein and flbrinogen levels, and white blood cell and differential counts 24 hours after stroke in two groups and 72 hours after stroke in primary hypertension combined with cerebral infarction group. RESULTS： All the 133 involved patients participated in the result analysis. The plasm C-reactive protein and fibrinogen levels, and white blood cell and neutrophil counts in patients with primary hypertension were all within the normal range. The plasm C-reactive protein and fibrinogen levels, and white blood cell and neu- trophil counts in patients with primary hypertension combined with cerebral infarction were significantly higher than those in patients with primary hypertension 24 hours after stroke and 72 hours after stroke respectively[24 hours after stroke：（32.12±11.76） mg/L vs. （5.02±3.21 ） mg/L;（4.64±0.75） g/L vs. （3.12±0.49） g/L; （9.32±81）×10^9 L^- 1 vs. （5.78±1.32）×10^9L^- 1 （7.85±2.38）×10^9 L^- 1 vs.（3.49±1.28）×10^9 L^-1,t =7.094, 5.759,4.106,5.491, respectively,all P〈 0.01; 72 hours after stroke： （47.62±18.43） mg/L vs. （32.12±11.76） mg/L; （5.08±0.82） g/L vs. （4.64±0.75） g/L, t =2.864,2.220, respectively, both P 〈 0.05]. CONCLUSION： The increase in fibrinogen level and white blood cell count are the important index in monitoring primary hypertension combined with acute cerebral infarction. The increase in plasm C-reactive protein and fibrinogen levels 72 hours after stroke indicates that plasma C-reactive protein and fibrinogen are very important in the development of disease.展开更多
The multi-parameter monitor is an essential instrument in medical rescue. It realizes the dynamic monitoring of human life parameters. In the verification process of the measurement parameters of the multi-parameter m...The multi-parameter monitor is an essential instrument in medical rescue. It realizes the dynamic monitoring of human life parameters. In the verification process of the measurement parameters of the multi-parameter monitor, it aims at the verification of ECG, non-invasive blood pressure and other indicators. This paper discusses the necessity of the metrological verification of the multi-parameter monitor, analyzes the problems and countermeasures in the metrological verification of the multi-parameter monitor.展开更多
In order to solve the problem of landslide hazard to people in our country, this paper takes a landslide in Shanxi province as an example, based on BDS/GPS dual-frequency ionosphere-free combination Precise Point Posi...In order to solve the problem of landslide hazard to people in our country, this paper takes a landslide in Shanxi province as an example, based on BDS/GPS dual-frequency ionosphere-free combination Precise Point Positioning (PPP), and analyzes the reliability of BDS/GPS dual-frequency ionosphere-free combination PPP in landslide deformation monitoring from convergence time and three-dimensional deformation of landslide. The research results show that the convergence of BDS/GPS dual-frequency precise point positioning can achieve centimeter-level accuracy in the landslide environment. The convergence data can accurately measure the horizontal and vertical changes of the landslide, and can provide a strong basis and support for the disaster prevention of the landslide.展开更多
Battery safety has emerged as a critical challenge for achieving carbon neutrality,driven by the increasing frequency of thermal runaway incidents in electric vehicles(EVs)and stationary energy storage systems(ESSs).C...Battery safety has emerged as a critical challenge for achieving carbon neutrality,driven by the increasing frequency of thermal runaway incidents in electric vehicles(EVs)and stationary energy storage systems(ESSs).Conventional battery monitoring technologies struggle to track multiple physicochemical parameters in real time,hindering early hazard detection.Embedded optical fiber sensors have gained prominence as a transformative solution for next-generation smart battery sensing,owing to their micrometer size,multiplexing capability,and electromagnetic immunity.However,comprehensive reviews focusing on their advancements in operando multi-parameter monitoring remain scarce,despite their critical importance for ensuring battery safety.To address this gap,this review first introduces a classification and the fundamental principles of advanced battery-oriented optical fiber sensors.Subsequently,it summarizes recent developments in single-parameter battery monitoring using optical fiber sensors.Building on this foundation,this review presents the first comprehensive analysis of multifunctional optical fiber sensing platforms capable of simultaneously tracking temperature,strain,pressure,refractive index,and monitoring battery aging.Targeted strategies are proposed to facilitate the practical development of this technology,including optimization of sensor integration techniques,minimizing sensor invasiveness,resolving the cross-sensitivity of fiber Bragg grating(FBG)through structural innovation,enhancing techno-economics,and combining with artificial intelligence(AI).By aligning academic research with industry requirements,this review provides a methodological roadmap for developing robust optical sensing systems to ensure battery safety in decarbonization-driven applications.展开更多
Rock bursts have become one of the most severe risks in underground coal mining and its early warning is an important component in the safety management. Microseismic(MS) monitoring is considered potentially as a powe...Rock bursts have become one of the most severe risks in underground coal mining and its early warning is an important component in the safety management. Microseismic(MS) monitoring is considered potentially as a powerful tool for the early warning of rock burst. In this study, an MS multi-parameter index system was established and the critical values of each index were estimated based on the normalized multi-information warning model of coal-rock dynamic failure. This index system includes bursting strain energy(BSE) index, time-space-magnitude independent information(TSMII) indices and timespace-magnitude compound information(TSMCI) indices. On the basis of this multi-parameter index system, a comprehensive analysis was conducted via introducing the R-value scoring method to calculate the weights of each index. To calibrate the multi-parameter index system and the associated comprehensive analysis, the weights of each index were first confirmed using historical MS data occurred in LW402102 of Hujiahe Coal Mine(China) over a period of four months. This calibrated comprehensive analysis of MS multi-parameter index system was then applied to pre-warn the occurrence of a subsequent rock burst incident in LW 402103. The results demonstrate that this multi-parameter index system combined with the comprehensive analysis are capable of quantitatively pre-warning rock burst risk.展开更多
Aiming at the characteristics of the poor steady ability, the short stable time and severe deformation behavior of weakly cemented soft surrounding rock around extraction roadway, a bolt–cable combined supporting tec...Aiming at the characteristics of the poor steady ability, the short stable time and severe deformation behavior of weakly cemented soft surrounding rock around extraction roadway, a bolt–cable combined supporting technology was proposed. Numerical simulation was performed by using FLAC3 D software to study the effects of different supporting systems. The simulation result proves that those supporting systems have good practical values. Based on real-time monitoring and analysis of the deformation of surrounding rock and the stress of supporting structure, real time information of deformation of surrounding rock and stress state of supporting structure of extraction roadway within weakly cemented strata was obtained. Monitoring results show that large deformation and failure of surrounding rock of extraction roadway within weakly cemented strata can be effectively controlled by the bolt–cable combined supporting technology, which ensures the long-term stability and safety of surrounding rock and supporting structure.展开更多
The mining area deformation monitoring theory and method using precise point positioning （PPP） ambi- guity resolution （AR） were studied, and an ambiguity fixing model with satellite and receiver combina- tion phas...The mining area deformation monitoring theory and method using precise point positioning （PPP） ambi- guity resolution （AR） were studied, and an ambiguity fixing model with satellite and receiver combina- tion phase delay （CPD） was proposed for zero-differenced PPP ambiguity fixing and its corresponding formula derivation was given. The data processing results for I h at six IGS stations in China show that 93% of ambiguities can be fixed within 10 min and all ambiguities can be fixed within 15 min. After ambi- guity fixing, the positioning accuracy is improved by more than 85% in the E and N directions, with abso- lute positioning accuracy reaching millimeter level, and it was improved by 70% in the U direction, reaching centimeter level; the proposed zero-differenced ambiguity fixing model can effectively improve the convergence rate and positioning accuracy in PPP. Data monitoring continuously conducted for half a year at four COPS stations of Shanxi China Coal Pingshuo Group validated the feasibility of using PPP in mining area deformation monitoring.展开更多
This study focused on the mechanical behavior of a deep-buried tunnel constructed in horizontally layered limestone,and investigated the effect of a new combined rockboltecable support system on the tunnel response.Th...This study focused on the mechanical behavior of a deep-buried tunnel constructed in horizontally layered limestone,and investigated the effect of a new combined rockboltecable support system on the tunnel response.The Yujingshan Tunnel,excavated through a giant karst cave,was used as a case study.Firstly,a multi-objective optimization model for the rockboltecable support was proposed by using fuzzy mathematics and multi-objective comprehensive decision-making principles.Subsequently,the parameters of the surrounding rock were calibrated by comparing the simulation results obtained by the discrete element method(DEM)with the field monitoring data to obtain an optimized support scheme based on the optimization model.Finally,the optimization scheme was applied to the karst cave section,which was divided into the B-and C-shaped sections.The distribution range of the rockboltecable support in the C-shaped section was larger than that in the B-shaped section.The field monitoring results,including tunnel crown settlement,horizontal convergence,and axial force of the rockboltecable system,were analyzed to assess the effectiveness of the optimization scheme.The maximum crown settlement and horizontal convergence were measured to be 25.9 mm and 35 mm,accounting for 0.1%and 0.2%of the tunnel height and span,respectively.Although the C-shaped section had poorer rock properties than the B-shaped section,the crown settlement and horizontal convergence in the C-shaped section ranged from 46%to 97%of those observed in the B-shaped section.The cable axial force in the Bshaped section was approximately 60%of that in the C-shaped section.The axial force in the crown rockbolt was much smaller than that in the sidewall rockbolt.Field monitoring results demonstrated that the optimized scheme effectively controlled the deformation of the layered surrounding rock,ensuring that it remained within a safe range.These results provide valuable references for the design of support systems in deep-buried tunnels situated in layered rock masses.展开更多
BACKGROUND With the widespread use of antimicrobial drugs,bacterial resistance has become a significant problem,posing a serious threat to public health.The prevalence of clinical infection strains in hospitals and th...BACKGROUND With the widespread use of antimicrobial drugs,bacterial resistance has become a significant problem,posing a serious threat to public health.The prevalence of clinical infection strains in hospitals and their drug sensitivities are key to the appropriate use of antibiotics in clinical practice.AIM To identify prevalent bacteria and their antibiotic resistance profiles in a hospital setting,thereby guiding effective antibiotic usage by clinicians.METHODS Specimens from across the institution were collected by the microbiology laboratory.The VITEK 2 compact fully automatic analyzer was used for bacterial identification and antibiotic sensitivity testing,and the WHONET5.6 software was utilized for statistical analysis.RESULTS A total of 12062 bacterial strains of key monitoring significance were detected.Staphylococcus aureus demonstrated widespread resistance to penicillin,but none of the strains were resistant to vancomycin or linezolid.Moreover,219 strains of methicillin-resistant coagulase-negative staphylococci and 110 strains of methicillin-resistant Staphylococcus aureus were detected.Enterococcus faecalis showed moderate resistance to the third-generation quinolones ciprofloxacin and levofloxacin,but its resistance to nitrofurantoin and tetracycline was low.Enterococcus faecium displayed significantly lower resistance to third-and fourthgeneration quinolones than Enterococcus faecalis.The resistance of two key monitoring strains,Escherichia coli and Klebsiella pneumoniae,to piperacillin/tazobactam was 5%-8%.However,none of the Escherichia coli and Klebsiella pneumoniae strains were resistant to meropenem.The resistance of Acinetobacter baumannii to piperacillin/sulbactam was nearly 90%.Nonetheless,the resistance to tigecycline was low,and Pseudomonas aeruginosa demonstrated minimal resistance in the antibiotic sensitivity test,maintaining a resistance of<10%to the cephalosporin antibiotics cefotetan and cefoperazone over the last 6 years.The resistance to amikacin remained at 0.2%over the past 3 years.CONCLUSION Our hospital’s overall antibiotic resistance rate was relatively stable from 2017 to 2022.The detection rates of key monitoring strains are reported quarterly and their resistance dynamics are monitored and communicated to the entire hospital,which can guide clinical antibiotic selection.展开更多
文摘BACKGROUND： Inflammatory reaction and the increased level of its accompanying active protein play an important role in the occurrence and development of cerebral infarction. C-reactive protein, fibrinogen and white blood cell, as the monitoring index of inflammatory reaction, are very important in the occurrence and development of acute cerebral infarction. OBJECTIVE： To make a comparison between patients with primary hypertension accompanied with acute cerebral infarction and with simple primary hypertension by observing the changes in plasma C-reactive protein and fibrinogen levels as well as white blood cell and differential counts and analyzing their significances. DESIGN ： Controlled observation SETTING ： Ward Building for VIP, Shenzhen Hospital, Peking University. PARTICIPANTS： Totally 133 patients with primary hypertension were selected from Ward Building for VIP, Shenzhen Hospital, Peking University during September 2003 to September 2005, The diagnostic criteria were based on the hypertension diagnosis criteria formulated by the 7^th World Health Organization-International Society of Hypertension Guidelines （WHO-ISH） in 1998. The informed consents were obtained from all the participants. The involved patients were assigned into two groups： primary hypertension group, in which, there were 65 patients with primary hypertension （ degree 2）, including 42 males and 23 females, with mean age of （61 ±14）years and mean blood pressure of （162.7±6.8）/（94.2±8.4） mm Hg （1 mm Hg =0.133 kPa）, and primary hypertension combined with cerebral infarction group, in which, there were 68 patients with primary hypertension combined with cerebral infarction （ meeting the diagnostic criteria formulated in the 4^th National Cerebrovascular Diseases Meeting in 1995 and diagnosed by skull CT or MRI to exclude the patients with lacunar infarction）, including 42 males and 26 females, with mean age of （56±15） years and mean blood pressure of （176.4±9.2）/（96.3±9.7） mm Hg. METHODS： Plasm C-reactive protein and fibrinogen levels, and white blood cell and differential counts of patients in the two groups were examined 24 hours after stroke. The above indexes were re-examined in the primary hypertension combined with cerebral infarction group 72 hours after stroke. White blood cell and differential counts were performed with laser method （East Asia FE-95001 RAM-1, Japan）. The level of C-reactive protein was measured with turbidimetry （BNII Automatic Systems For Analysis, USA）. The level of fibrinogen was measured with algorithm method when prothrombin time was normal and with Clauss method when prothrombin time was abnormal （ACL Automatic Coagulation Analyzer, USA）. MAIN OUTCOME MEASURES： The plasm C-reactive protein and flbrinogen levels, and white blood cell and differential counts 24 hours after stroke in two groups and 72 hours after stroke in primary hypertension combined with cerebral infarction group. RESULTS： All the 133 involved patients participated in the result analysis. The plasm C-reactive protein and fibrinogen levels, and white blood cell and neutrophil counts in patients with primary hypertension were all within the normal range. The plasm C-reactive protein and fibrinogen levels, and white blood cell and neu- trophil counts in patients with primary hypertension combined with cerebral infarction were significantly higher than those in patients with primary hypertension 24 hours after stroke and 72 hours after stroke respectively[24 hours after stroke：（32.12±11.76） mg/L vs. （5.02±3.21 ） mg/L;（4.64±0.75） g/L vs. （3.12±0.49） g/L; （9.32±81）×10^9 L^- 1 vs. （5.78±1.32）×10^9L^- 1 （7.85±2.38）×10^9 L^- 1 vs.（3.49±1.28）×10^9 L^-1,t =7.094, 5.759,4.106,5.491, respectively,all P〈 0.01; 72 hours after stroke： （47.62±18.43） mg/L vs. （32.12±11.76） mg/L; （5.08±0.82） g/L vs. （4.64±0.75） g/L, t =2.864,2.220, respectively, both P 〈 0.05]. CONCLUSION： The increase in fibrinogen level and white blood cell count are the important index in monitoring primary hypertension combined with acute cerebral infarction. The increase in plasm C-reactive protein and fibrinogen levels 72 hours after stroke indicates that plasma C-reactive protein and fibrinogen are very important in the development of disease.
文摘The multi-parameter monitor is an essential instrument in medical rescue. It realizes the dynamic monitoring of human life parameters. In the verification process of the measurement parameters of the multi-parameter monitor, it aims at the verification of ECG, non-invasive blood pressure and other indicators. This paper discusses the necessity of the metrological verification of the multi-parameter monitor, analyzes the problems and countermeasures in the metrological verification of the multi-parameter monitor.
文摘In order to solve the problem of landslide hazard to people in our country, this paper takes a landslide in Shanxi province as an example, based on BDS/GPS dual-frequency ionosphere-free combination Precise Point Positioning (PPP), and analyzes the reliability of BDS/GPS dual-frequency ionosphere-free combination PPP in landslide deformation monitoring from convergence time and three-dimensional deformation of landslide. The research results show that the convergence of BDS/GPS dual-frequency precise point positioning can achieve centimeter-level accuracy in the landslide environment. The convergence data can accurately measure the horizontal and vertical changes of the landslide, and can provide a strong basis and support for the disaster prevention of the landslide.
基金the financial supports of the National Natural Science Foundation of China(No.52372200)a project supported by the State Key Laboratory of Mechanics and Control for Aerospace Structures(No.MCAS-S-0324G01)。
文摘Battery safety has emerged as a critical challenge for achieving carbon neutrality,driven by the increasing frequency of thermal runaway incidents in electric vehicles(EVs)and stationary energy storage systems(ESSs).Conventional battery monitoring technologies struggle to track multiple physicochemical parameters in real time,hindering early hazard detection.Embedded optical fiber sensors have gained prominence as a transformative solution for next-generation smart battery sensing,owing to their micrometer size,multiplexing capability,and electromagnetic immunity.However,comprehensive reviews focusing on their advancements in operando multi-parameter monitoring remain scarce,despite their critical importance for ensuring battery safety.To address this gap,this review first introduces a classification and the fundamental principles of advanced battery-oriented optical fiber sensors.Subsequently,it summarizes recent developments in single-parameter battery monitoring using optical fiber sensors.Building on this foundation,this review presents the first comprehensive analysis of multifunctional optical fiber sensing platforms capable of simultaneously tracking temperature,strain,pressure,refractive index,and monitoring battery aging.Targeted strategies are proposed to facilitate the practical development of this technology,including optimization of sensor integration techniques,minimizing sensor invasiveness,resolving the cross-sensitivity of fiber Bragg grating(FBG)through structural innovation,enhancing techno-economics,and combining with artificial intelligence(AI).By aligning academic research with industry requirements,this review provides a methodological roadmap for developing robust optical sensing systems to ensure battery safety in decarbonization-driven applications.
基金provided by the State Key Research Development Program of China (No.2016YFC0801403)Key Research Development Program of Jiangsu Provence (No.BE2015040)+1 种基金National Natural Science Foundation of China (Nos.51674253,51734009 and 51604270)Natural Science Foundation of Jiangsu Province (No.BK20171191)
文摘Rock bursts have become one of the most severe risks in underground coal mining and its early warning is an important component in the safety management. Microseismic(MS) monitoring is considered potentially as a powerful tool for the early warning of rock burst. In this study, an MS multi-parameter index system was established and the critical values of each index were estimated based on the normalized multi-information warning model of coal-rock dynamic failure. This index system includes bursting strain energy(BSE) index, time-space-magnitude independent information(TSMII) indices and timespace-magnitude compound information(TSMCI) indices. On the basis of this multi-parameter index system, a comprehensive analysis was conducted via introducing the R-value scoring method to calculate the weights of each index. To calibrate the multi-parameter index system and the associated comprehensive analysis, the weights of each index were first confirmed using historical MS data occurred in LW402102 of Hujiahe Coal Mine(China) over a period of four months. This calibrated comprehensive analysis of MS multi-parameter index system was then applied to pre-warn the occurrence of a subsequent rock burst incident in LW 402103. The results demonstrate that this multi-parameter index system combined with the comprehensive analysis are capable of quantitatively pre-warning rock burst risk.
基金financially supported by the National Natural Science Foundation of China (Nos. 51174196, 51204168, 51109209 and 51309222)the Youth Fund Project of Jiangsu Province Natural Science Foundation (No. BK20130193)
文摘Aiming at the characteristics of the poor steady ability, the short stable time and severe deformation behavior of weakly cemented soft surrounding rock around extraction roadway, a bolt–cable combined supporting technology was proposed. Numerical simulation was performed by using FLAC3 D software to study the effects of different supporting systems. The simulation result proves that those supporting systems have good practical values. Based on real-time monitoring and analysis of the deformation of surrounding rock and the stress of supporting structure, real time information of deformation of surrounding rock and stress state of supporting structure of extraction roadway within weakly cemented strata was obtained. Monitoring results show that large deformation and failure of surrounding rock of extraction roadway within weakly cemented strata can be effectively controlled by the bolt–cable combined supporting technology, which ensures the long-term stability and safety of surrounding rock and supporting structure.
基金Financial support from the National Natural Science Foundation of China (No. 41074010)the Jiangsu Innovation Works Fund of Postgraduate (No. CXZZ11-0299)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘The mining area deformation monitoring theory and method using precise point positioning （PPP） ambi- guity resolution （AR） were studied, and an ambiguity fixing model with satellite and receiver combina- tion phase delay （CPD） was proposed for zero-differenced PPP ambiguity fixing and its corresponding formula derivation was given. The data processing results for I h at six IGS stations in China show that 93% of ambiguities can be fixed within 10 min and all ambiguities can be fixed within 15 min. After ambi- guity fixing, the positioning accuracy is improved by more than 85% in the E and N directions, with abso- lute positioning accuracy reaching millimeter level, and it was improved by 70% in the U direction, reaching centimeter level; the proposed zero-differenced ambiguity fixing model can effectively improve the convergence rate and positioning accuracy in PPP. Data monitoring continuously conducted for half a year at four COPS stations of Shanxi China Coal Pingshuo Group validated the feasibility of using PPP in mining area deformation monitoring.
基金supported by the Fundamental Research Funds for the Central Universities (Grant No.2023JBZY024)Beijing Natural Science Foundation (Grant No.9244040)opening Fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology (Grant No.SKLGP2023K015).
文摘This study focused on the mechanical behavior of a deep-buried tunnel constructed in horizontally layered limestone,and investigated the effect of a new combined rockboltecable support system on the tunnel response.The Yujingshan Tunnel,excavated through a giant karst cave,was used as a case study.Firstly,a multi-objective optimization model for the rockboltecable support was proposed by using fuzzy mathematics and multi-objective comprehensive decision-making principles.Subsequently,the parameters of the surrounding rock were calibrated by comparing the simulation results obtained by the discrete element method(DEM)with the field monitoring data to obtain an optimized support scheme based on the optimization model.Finally,the optimization scheme was applied to the karst cave section,which was divided into the B-and C-shaped sections.The distribution range of the rockboltecable support in the C-shaped section was larger than that in the B-shaped section.The field monitoring results,including tunnel crown settlement,horizontal convergence,and axial force of the rockboltecable system,were analyzed to assess the effectiveness of the optimization scheme.The maximum crown settlement and horizontal convergence were measured to be 25.9 mm and 35 mm,accounting for 0.1%and 0.2%of the tunnel height and span,respectively.Although the C-shaped section had poorer rock properties than the B-shaped section,the crown settlement and horizontal convergence in the C-shaped section ranged from 46%to 97%of those observed in the B-shaped section.The cable axial force in the Bshaped section was approximately 60%of that in the C-shaped section.The axial force in the crown rockbolt was much smaller than that in the sidewall rockbolt.Field monitoring results demonstrated that the optimized scheme effectively controlled the deformation of the layered surrounding rock,ensuring that it remained within a safe range.These results provide valuable references for the design of support systems in deep-buried tunnels situated in layered rock masses.
文摘BACKGROUND With the widespread use of antimicrobial drugs,bacterial resistance has become a significant problem,posing a serious threat to public health.The prevalence of clinical infection strains in hospitals and their drug sensitivities are key to the appropriate use of antibiotics in clinical practice.AIM To identify prevalent bacteria and their antibiotic resistance profiles in a hospital setting,thereby guiding effective antibiotic usage by clinicians.METHODS Specimens from across the institution were collected by the microbiology laboratory.The VITEK 2 compact fully automatic analyzer was used for bacterial identification and antibiotic sensitivity testing,and the WHONET5.6 software was utilized for statistical analysis.RESULTS A total of 12062 bacterial strains of key monitoring significance were detected.Staphylococcus aureus demonstrated widespread resistance to penicillin,but none of the strains were resistant to vancomycin or linezolid.Moreover,219 strains of methicillin-resistant coagulase-negative staphylococci and 110 strains of methicillin-resistant Staphylococcus aureus were detected.Enterococcus faecalis showed moderate resistance to the third-generation quinolones ciprofloxacin and levofloxacin,but its resistance to nitrofurantoin and tetracycline was low.Enterococcus faecium displayed significantly lower resistance to third-and fourthgeneration quinolones than Enterococcus faecalis.The resistance of two key monitoring strains,Escherichia coli and Klebsiella pneumoniae,to piperacillin/tazobactam was 5%-8%.However,none of the Escherichia coli and Klebsiella pneumoniae strains were resistant to meropenem.The resistance of Acinetobacter baumannii to piperacillin/sulbactam was nearly 90%.Nonetheless,the resistance to tigecycline was low,and Pseudomonas aeruginosa demonstrated minimal resistance in the antibiotic sensitivity test,maintaining a resistance of<10%to the cephalosporin antibiotics cefotetan and cefoperazone over the last 6 years.The resistance to amikacin remained at 0.2%over the past 3 years.CONCLUSION Our hospital’s overall antibiotic resistance rate was relatively stable from 2017 to 2022.The detection rates of key monitoring strains are reported quarterly and their resistance dynamics are monitored and communicated to the entire hospital,which can guide clinical antibiotic selection.
