The specialized equipment utilized in long-line tunnel engineering is evolving towards large-scale,multifunctional,and complex orientations.The vibration caused by the high-frequency units during regular operation is ...The specialized equipment utilized in long-line tunnel engineering is evolving towards large-scale,multifunctional,and complex orientations.The vibration caused by the high-frequency units during regular operation is supported by the foundation of the units,and the magnitude of vibration and the operating frequency fluctuate in different engineering contexts,leading to variations in the dynamic response of the foundation.The high-frequency units yield significantly diverse outcomes under different startup conditions and times,resulting in failure to meet operational requirements,influencing the normal function of the tunnel,and causing harm to the foundation structure,personnel,and property in severe cases.This article formulates a finite element numerical computation model for solid elements using three-dimensional elastic body theory and integrates field measurements to substantiate and ascertain the crucial parameter configurations of the finite element model.By proposing a comprehensive startup timing function for high-frequency dynamic machines under different startup conditions,simulating the frequency andmagnitude variations during the startup process,and suggesting functions for changes in frequency and magnitude,a simulated startup schedule function for high-frequency machines is created through coupling.Taking into account the selection of the transient dynamic analysis step length,the dynamic response results for the lower dynamic foundation during its fundamental frequency crossing process are obtained.The validation checks if the structural magnitude surpasses the safety threshold during the critical phase of unit startup traversing the structural resonance region.The design recommendations for high-frequency units’dynamic foundations are provided,taking into account the startup process of the machine and ensuring the safe operation of the tunnel.展开更多
AIM： To study the influence of high-frequency electric surgical knives on healing of abdominal incision. METHODS： Two hundred and forty white rats were divided into 10^0, 10^2, 10^5, and 10^8 groups and rat models o...AIM： To study the influence of high-frequency electric surgical knives on healing of abdominal incision. METHODS： Two hundred and forty white rats were divided into 10^0, 10^2, 10^5, and 10^8 groups and rat models of abdominal operation were induced by using electric surgical knives and common lancets respectively. Then they were respectively given hypodermic injections of normal saline and 0.2 mL quantitative mixture of Escherichia coil, Staphylococcus aureus and Pseudornonas aeruginosa at a concentration of 10^2, 10^5 and 10^8. On the basis of the animal experiment, 220 patients undergoing abdominal operations （above type Ⅱ） were randomly allocated into one of following three groups： electric knife （EK, 93 cases）, electro-coagulation （EC, 55 cases） and control （72 cases）. High-frequency electric surgical knives were used to dissect abdominal tissues and electro-coagulation for hemostasis in EK group. Common lancets and electro-coagulation were applied in EC group. Common lancets and tieing silk suture were used in the controls. RESULTS： In all the groups except group 10^0, infection rate of incisional wounds made by electric surgical knives were remarkably higher than that with common lancets. Furthermore, there were significant differences in groups 10^2, 10^5, and 10^8 （P 〈 0.05）, but not in group 10^0 （P 〉 0.05） between EK and EC groups. Clinical studies showed a delayed wound healing in 16 cases （17.20%） in EK, 11 cases （16.36%） in EC and 2 cases （2.86%）in the control groups. A significant difference between EK and the control groups （χ^2= 8.57, P 〈 0.01）, and between EC and the control groups （χ^2 = 5.66, P 〈 0.05） was observed, but not between EK and EC （χ^2= 0.017, P 〉 0.05）. CONCLUSION： High-frequency electric knives may remarkably delay abdominal incision healing. Its application should be minimized so as to reduce the possibility of postoperative complications.展开更多
Electro-hydraulic vibration equipment(EHVE)is widely used in vibration environment simulation tests,such as vehicles,weapons,ships,aerospace,nuclear industries and seismic waves replication,etc.,due to its large outpu...Electro-hydraulic vibration equipment(EHVE)is widely used in vibration environment simulation tests,such as vehicles,weapons,ships,aerospace,nuclear industries and seismic waves replication,etc.,due to its large output power,displacement and thrust,as well as good workload adaptation and multi-controllable parameters.Based on the domestic and overseas development of high-frequency EHVE,dividing them into servo-valve controlled vibration equipment and rotary-valve controlled vibration equipment.The research status and progress of high-frequency electro-hydraulic vibration control technology(EHVCT)are discussed,from the perspective of vibration waveform control and vibration controller.The problems of current electro-hydraulic vibration system bandwidth and waveform distortion control,stability control,offset control and complex vibration waveform generation in high-frequency vibration conditions are pointed out.Combining the existing rotary-valve controlled high-frequency electro-hydraulic vibration method,a new twin-valve independently controlled high-frequency electro-hydraulic vibration method is proposed to break through the limitations of current electro-hydraulic vibration technology in terms of system frequency bandwidth and waveform distortion.The new method can realize independent adjustment and control of vibration waveform frequency,amplitude and offset under high-frequency vibration conditions,and provide a new idea for accurate simulation of high-frequency vibration waveform.展开更多
The exact risk association of coronavirus disease 2019(COVID-19)for surgeons is not quantified which may be affected by their risk of exposure and individual factors.The objective of this review is to quantify the ris...The exact risk association of coronavirus disease 2019(COVID-19)for surgeons is not quantified which may be affected by their risk of exposure and individual factors.The objective of this review is to quantify the risk of COVID-19 among surgeons,and explore whether facemask can minimise the risk of COVID-19 among surgeons.A systematised review was carried out by searching MEDLINE to locate items on severe acute respiratory syndrome coronavirus 2 or COVID-19 in relation to health care workers(HCWs)especially those work in surgical specialities including surgical nurses and intensivists.Additionally,systematic reviews that assessed the effectiveness of facemask against viral respiratory infections,including COVID-19,among HCWs were identified.Data from identified articles were abstracted,synthesised and summarised.Fourteen primary studies that provided data on severe acute respiratory syndrome coronavirus 2 infection or experience among surgeons and 11 systematic reviews that provided evidence of the effectiveness of facemask(and other personal protective equipment)were summarised.Although the risk of COVID-19 could not be quantified precisely among surgeons,about 14%of HCWs including surgeons had COVID-19,there could be variations depending on settings.Facemask was found to be somewhat protective against COVID-19,but the HCWs’compliance was highly variable ranging from zero to 100%.Echoing surgical societies’guidelines we continue to recommend facemask use among surgeons to prevent COVID-19.展开更多
Objective:Surgeons are required to wear heavy personal protective equipment while delivering care to patients during the COVID-19 pandemic.We examined the impact of wearing double gloves on surgeons’performance in la...Objective:Surgeons are required to wear heavy personal protective equipment while delivering care to patients during the COVID-19 pandemic.We examined the impact of wearing double gloves on surgeons’performance in laparoscopic surgery.Methods:Eleven surgeons-in-training at the Surgical Simulation Research Lab of the University of Alberta were recruited to perform laparoscopic cutting tasks in simulation while wearing none,one pair,and two pairs of surgical gloves.Forces applied to laparoscopic instruments were measured.Results:Wearing gloves prolonged task times(one pair of gloves:301.6±61.7 s;two pairs of gloves:295.8±65.3 s)compared with no gloves(241.7±46.9 s;p=0.043).Wearing double gloves increased cutting errors(20.4±5.1 mm^(2))compared with wearing one pair of gloves(16.9±5.5 mm^(2))and no gloves(14.4±4.6 mm^(2);p=0.030).Wearing gloves reduced the peak force(one pair of gloves:2.4±0.7 N;two pairs of gloves:2.7±0.6 N;no gloves:3.4±1.4 N;p=0.049),and the total force(one pair of gloves:10.1±2.8 N;two pairs of gloves:10.3±2.6 N;no glove:12.6±1.9 N;p=0.048)delivered onto lapa-roscopic scissors compared with wearing no glove.Conclusion:The combined effects of wearing heavy gloves and using tools reduced the touching sensation,which limited the surgeons’confidence in performing surgical tasks.Increasing practice in simulation is suggested to allow surgeons to overcome difficulties brought by personal protective equipment.展开更多
基金Smart Integration Key Technologies and Application Demonstrations of Large Scale Underground Space Disaster Prevention and Reduction in Guangzhou International Financial City([2021]–KJ058).
文摘The specialized equipment utilized in long-line tunnel engineering is evolving towards large-scale,multifunctional,and complex orientations.The vibration caused by the high-frequency units during regular operation is supported by the foundation of the units,and the magnitude of vibration and the operating frequency fluctuate in different engineering contexts,leading to variations in the dynamic response of the foundation.The high-frequency units yield significantly diverse outcomes under different startup conditions and times,resulting in failure to meet operational requirements,influencing the normal function of the tunnel,and causing harm to the foundation structure,personnel,and property in severe cases.This article formulates a finite element numerical computation model for solid elements using three-dimensional elastic body theory and integrates field measurements to substantiate and ascertain the crucial parameter configurations of the finite element model.By proposing a comprehensive startup timing function for high-frequency dynamic machines under different startup conditions,simulating the frequency andmagnitude variations during the startup process,and suggesting functions for changes in frequency and magnitude,a simulated startup schedule function for high-frequency machines is created through coupling.Taking into account the selection of the transient dynamic analysis step length,the dynamic response results for the lower dynamic foundation during its fundamental frequency crossing process are obtained.The validation checks if the structural magnitude surpasses the safety threshold during the critical phase of unit startup traversing the structural resonance region.The design recommendations for high-frequency units’dynamic foundations are provided,taking into account the startup process of the machine and ensuring the safe operation of the tunnel.
文摘AIM： To study the influence of high-frequency electric surgical knives on healing of abdominal incision. METHODS： Two hundred and forty white rats were divided into 10^0, 10^2, 10^5, and 10^8 groups and rat models of abdominal operation were induced by using electric surgical knives and common lancets respectively. Then they were respectively given hypodermic injections of normal saline and 0.2 mL quantitative mixture of Escherichia coil, Staphylococcus aureus and Pseudornonas aeruginosa at a concentration of 10^2, 10^5 and 10^8. On the basis of the animal experiment, 220 patients undergoing abdominal operations （above type Ⅱ） were randomly allocated into one of following three groups： electric knife （EK, 93 cases）, electro-coagulation （EC, 55 cases） and control （72 cases）. High-frequency electric surgical knives were used to dissect abdominal tissues and electro-coagulation for hemostasis in EK group. Common lancets and electro-coagulation were applied in EC group. Common lancets and tieing silk suture were used in the controls. RESULTS： In all the groups except group 10^0, infection rate of incisional wounds made by electric surgical knives were remarkably higher than that with common lancets. Furthermore, there were significant differences in groups 10^2, 10^5, and 10^8 （P 〈 0.05）, but not in group 10^0 （P 〉 0.05） between EK and EC groups. Clinical studies showed a delayed wound healing in 16 cases （17.20%） in EK, 11 cases （16.36%） in EC and 2 cases （2.86%）in the control groups. A significant difference between EK and the control groups （χ^2= 8.57, P 〈 0.01）, and between EC and the control groups （χ^2 = 5.66, P 〈 0.05） was observed, but not between EK and EC （χ^2= 0.017, P 〉 0.05）. CONCLUSION： High-frequency electric knives may remarkably delay abdominal incision healing. Its application should be minimized so as to reduce the possibility of postoperative complications.
基金Supported by National Natural Science Foundation of China.(Grant Nos.51605431,51675472)
文摘Electro-hydraulic vibration equipment(EHVE)is widely used in vibration environment simulation tests,such as vehicles,weapons,ships,aerospace,nuclear industries and seismic waves replication,etc.,due to its large output power,displacement and thrust,as well as good workload adaptation and multi-controllable parameters.Based on the domestic and overseas development of high-frequency EHVE,dividing them into servo-valve controlled vibration equipment and rotary-valve controlled vibration equipment.The research status and progress of high-frequency electro-hydraulic vibration control technology(EHVCT)are discussed,from the perspective of vibration waveform control and vibration controller.The problems of current electro-hydraulic vibration system bandwidth and waveform distortion control,stability control,offset control and complex vibration waveform generation in high-frequency vibration conditions are pointed out.Combining the existing rotary-valve controlled high-frequency electro-hydraulic vibration method,a new twin-valve independently controlled high-frequency electro-hydraulic vibration method is proposed to break through the limitations of current electro-hydraulic vibration technology in terms of system frequency bandwidth and waveform distortion.The new method can realize independent adjustment and control of vibration waveform frequency,amplitude and offset under high-frequency vibration conditions,and provide a new idea for accurate simulation of high-frequency vibration waveform.
文摘The exact risk association of coronavirus disease 2019(COVID-19)for surgeons is not quantified which may be affected by their risk of exposure and individual factors.The objective of this review is to quantify the risk of COVID-19 among surgeons,and explore whether facemask can minimise the risk of COVID-19 among surgeons.A systematised review was carried out by searching MEDLINE to locate items on severe acute respiratory syndrome coronavirus 2 or COVID-19 in relation to health care workers(HCWs)especially those work in surgical specialities including surgical nurses and intensivists.Additionally,systematic reviews that assessed the effectiveness of facemask against viral respiratory infections,including COVID-19,among HCWs were identified.Data from identified articles were abstracted,synthesised and summarised.Fourteen primary studies that provided data on severe acute respiratory syndrome coronavirus 2 infection or experience among surgeons and 11 systematic reviews that provided evidence of the effectiveness of facemask(and other personal protective equipment)were summarised.Although the risk of COVID-19 could not be quantified precisely among surgeons,about 14%of HCWs including surgeons had COVID-19,there could be variations depending on settings.Facemask was found to be somewhat protective against COVID-19,but the HCWs’compliance was highly variable ranging from zero to 100%.Echoing surgical societies’guidelines we continue to recommend facemask use among surgeons to prevent COVID-19.
基金funded by the Alberta Jobs,Economy and Innovation Ministry's Major Initiatives Fund to Dr.Zheng(MIF01 T4 P1 Zheng)the Royal College of Physicians and Surgeons of Canada Medical Education Research Award to Dr.Zheng(RCPSC 16/MERC-09).
文摘Objective:Surgeons are required to wear heavy personal protective equipment while delivering care to patients during the COVID-19 pandemic.We examined the impact of wearing double gloves on surgeons’performance in laparoscopic surgery.Methods:Eleven surgeons-in-training at the Surgical Simulation Research Lab of the University of Alberta were recruited to perform laparoscopic cutting tasks in simulation while wearing none,one pair,and two pairs of surgical gloves.Forces applied to laparoscopic instruments were measured.Results:Wearing gloves prolonged task times(one pair of gloves:301.6±61.7 s;two pairs of gloves:295.8±65.3 s)compared with no gloves(241.7±46.9 s;p=0.043).Wearing double gloves increased cutting errors(20.4±5.1 mm^(2))compared with wearing one pair of gloves(16.9±5.5 mm^(2))and no gloves(14.4±4.6 mm^(2);p=0.030).Wearing gloves reduced the peak force(one pair of gloves:2.4±0.7 N;two pairs of gloves:2.7±0.6 N;no gloves:3.4±1.4 N;p=0.049),and the total force(one pair of gloves:10.1±2.8 N;two pairs of gloves:10.3±2.6 N;no glove:12.6±1.9 N;p=0.048)delivered onto lapa-roscopic scissors compared with wearing no glove.Conclusion:The combined effects of wearing heavy gloves and using tools reduced the touching sensation,which limited the surgeons’confidence in performing surgical tasks.Increasing practice in simulation is suggested to allow surgeons to overcome difficulties brought by personal protective equipment.
