The general principle of utilizing the BGK equation to simulate a macroscopic gas flow is illustrated. Two typical examples, i.e., a low-speed axisymmetric submerged jet and the Prandtl-Meyer expansion to a vacuum, ar...The general principle of utilizing the BGK equation to simulate a macroscopic gas flow is illustrated. Two typical examples, i.e., a low-speed axisymmetric submerged jet and the Prandtl-Meyer expansion to a vacuum, are presented for validating the feasibility and accuracy of the BGK-equation simulation in continuum and non-continuum flow regimes. This approach is then used to simulate the exhaust plume formed by a small manoeuvre thruster of an artificial satellite in the outer space. The plume impingement on a flat surface perpendicular to the nozzle axis is also simulated by the same method. In the latter case the impingement force acting on the flat surface is calculated. When the flow reaches to the steady state the calculated impingement force is reasonably compared with the theoretical value of the nozzle thrust.展开更多
Background: Intermittent Pringle manoeuvre resul- ted in less blood loss and better preservation of liver function when it was applied for fewer than 120 mi- nutes. The mechanism of better preservation of liver functi...Background: Intermittent Pringle manoeuvre resul- ted in less blood loss and better preservation of liver function when it was applied for fewer than 120 mi- nutes. The mechanism of better preservation of liver function under intermittent Pringle manoeuvre at molecular level remains unclear. Furthermore, the ultrastructural features in the liver with chronic di- seases under intermittent Pringle manoeuvre have not been studied. The aim of the study is to investigate the expression of stress genes and ultrastructural change of the liver under intermittent Pringle ma- noeuvre. Methods: From July 1995 to February 1998, 131 pa- tients underwent hepatectomy for liver tumours (61 patients without Pringle manoeuvre and 70 patients with intermittent Pringle manoeuvre). Twenty-five patients (15 with Pringle manoeuvre and 10 without Pringle manoeuvre) were included in the study of he- patic stress gene expression during hepatectomy. Twenty-two patients (18 patients with intermittent Pringle manoeuvre and four patients without Pringle manoeuvre) were randomly assigned for electron mi- croscopic examination. Results: For the expression of stress genes, both the heat shock genes (HSP 70A and HSC 70) and acute phase genes (TNF-α and interleukin-6) were detec- ted simultaneously in the patients with or without in- termittent Pringle manoeuvre. The patients under in- termittent Pringle manoeuvre had relatively higher mRNA levels of heat shock gene 70 family, which is related to intracellular repair and protection. Induc- tion of TNF-α and interleukin-6 genes, which con- tributed to ischaemia-reperfusion injury and posto- perative complication, was not found in the patients under intermittent Pringle manoeuvre. Under the e- lectron microscopy, the hepatic ultrastructure was well maintained under intermittent Pringle manoeu- vre whatever the liver status, even when the accumu- lated ischaemic duration was extended to 120 min. Conclusion: Intermittent Pringle manoeuvre induced relatively higher expression of heat shock genes, which are related to intracellular homeostasis, and is consistent with the well maintenance of liver ultra- structure.展开更多
This paper proposes a parity recognition of blade number and manoeuvre intention classification algorithm of rotor target based on the convolutional neural network(CNN) using micro Doppler features. Firstly, the time-...This paper proposes a parity recognition of blade number and manoeuvre intention classification algorithm of rotor target based on the convolutional neural network(CNN) using micro Doppler features. Firstly, the time-frequency spectrograms are acquired from the radar echo by the short-time Fourier transform.Secondly, based on the obtained spectrograms, a seven-layer CNN architecture is built to recognize the blade-number parity and classify the manoeuvre intention of the rotor target. The constructed architecture contains a leaky rectified linear unit and a dropout layer to accelerate the convergence of the architecture and avoid over-fitting. Finally, the spectrograms of the datasets are divided into three different ratios, i.e., 20%, 33% and 50%,and the cross validation is used to verify the effectiveness of the constructed CNN architecture. Simulation results show that, on the one hand, as the ratio of training data increases, the recognition accuracy of parity and manoeuvre intention is improved at the same signal-to-noise ratio(SNR);on the other hand, the proposed algorithm also has a strong robustness: the accuracy can still reach 90.72% with an SNR of – 6 dB.展开更多
Quiescent Type of H. Rosen & Stage 2 of C.L. Romano et al. for Infected Non Union of Femur after K-nailing (Küntscher nailing) require no debridement & removal of nail and therefore can be treated by a si...Quiescent Type of H. Rosen & Stage 2 of C.L. Romano et al. for Infected Non Union of Femur after K-nailing (Küntscher nailing) require no debridement & removal of nail and therefore can be treated by a single stage procedure. There are a few reports of treating aseptic non-union of femur by compression alone or compression distraction over nail by Ilizarov Technique. However, no case of Infected Non-Union femur being treated by Accordion Manoeuvre with Ilizarov over nail in situ (i.e. without exchange nailing) has been reported so far. Here, we are reporting a case of Infected Non-Union following K-nailing for a fracture shaft of femur in a 15-year-old female, who was treated by this technique as a single stage procedure. An Ilizarov frame was mounted on the femur with nail in situ followed by Accordion Manoeuvre. The fracture was healed in 5.6 months with two cycles of Accordion Manoeuvre followed by rhythmic compression. There was no recurrence of infection.展开更多
Objective This study aimed to examine the association of primary open-angle glaucoma(POAG)with autonomic dysfunction by assessing the differences in systemic and ocular responses to an autonomic provocation test,the V...Objective This study aimed to examine the association of primary open-angle glaucoma(POAG)with autonomic dysfunction by assessing the differences in systemic and ocular responses to an autonomic provocation test,the Valsalva manoeuvre(VM),between POAG patients and normal subjects.Methods Forty POAG and forty control subjects were subjected to the VM.Systemic and ocular parameters were measured at baseline,phase 2,and phase 4 of the VM(VM2 and VM4),where VM2 and VM4 are sympathetic and parasympathetic nervous activation states,respectively.Heart rate variability was used to assess the autonomic nervous activity,among which the high-frequency component(HF)and the low-frequency(LF)/HF ratio were used as indices of parasympathetic and sympathetic activation,respectively.Results POAG patients demonstrated higher sympathetic activation(LF/HF ratio median:2.17 vs.1.53,P=0.000)than controls at baseline and exhibited attenuated sympathetic and parasympathetic responses(a smaller change in LF/HF and HF values)during the VM than controls.During VM,the intraocular pressure(IOP),mean blood pressure(MAP),mean ocular perfusion pressure(MOPP),and the Schlemm’s canal area(SCAR)increased from baseline to VM2 and then decreased from VM2 to VM4 in both the POAG and control groups(all P<0.05).However,when we compared the changes above,the fluctuations in IOP,MAP,and MOPP were more pronounced in POAG than in controls(all P<0.05),while the changes in amplitudes of SCAR were smaller in POAG(P<0.05).Furthermore,from VM2 to VM4,the choroid thickness(ChT)in the POAG group was significantly decreased,while it was unchanged in normal subjects(P=0.258).A regression analysis showed a significant correlation of the baseline LF/HF with IOP change values(ΔIOP)from baseline to VM2 in POAG(R^(2)=0.147,P=0.014).Conclusion Patients with POAG showed more pronounced fluctuations in IOP,MAP,MOPP and ChT during the VM than controls.These reactions could be associated with autonomic dysfunction in POAG.展开更多
Heart attack is an extremely urgent medical condition which may occur at any time and can affect anybody and means the failure of the pump function of the heart and it represents the condition which brings to death. T...Heart attack is an extremely urgent medical condition which may occur at any time and can affect anybody and means the failure of the pump function of the heart and it represents the condition which brings to death. The aim of this study is the training, which is the acquisition of knowledge, abilities and skills as a result of education and practice in a certain discipline and this project has been created to make as accessible to all as possible the information about the identification and treatment of heart attack. However, the key objective has been involving only laic blind subjects in the trial and theoretical-practical course to support vital functions （BLS （basic life support））, to demonstrate that in a state of emergency, like a heart attack, even a subject affected by visual impairment, if properly trained, can be very helpful and can contribute to save a life. Fifteen partially sighted and sightless executors have participated in this study. In order to evaluate learning objectives of the course, participants have completed a pre-course test to examine these areas： cognitive and emotional, motivational, theoretical-practical; while, at the end of the course, participants have completed a comment card about the course. At the end of this study it can be seen that blind subjects do not present any type of limitation in the learning and in the execution of BLS manoeuvres after an appropriate training.展开更多
Cardiac Arrest (CA) is a major health problem, due to short and long-term sequel? and to associated mortality. Despite the improvement of out-of-hospital and in-hospital resuscitation manoeuvres, unexpected sudden fat...Cardiac Arrest (CA) is a major health problem, due to short and long-term sequel? and to associated mortality. Despite the improvement of out-of-hospital and in-hospital resuscitation manoeuvres, unexpected sudden fatal events occur. The authors reported the features of a series of sudden death (SD) cases where cardiopulmonary resuscitation (CPR) was performed. Files of 1053 medico-legal autopsies, from victims aged ≥18 years-old, were reviewed. Cardiac Arrest leading to Sudden Death were found in 477 cases (45.3%), but only 199 (42%) of these had been submitted to resuscitation manoeuvres. There was an elderly male predominance. Both non-cardiac and cardiac CA/SD causes were present, despite the higher coronary artery disease incidence. Both out-of-hospital and in-hospital events took place. Age, severity of the disease, comorbidities and predominance of out-of-hospital CA were obstacles to successful CPR, leading to SD. Knowing the population characteristics may help to improve Emergency Assistance.展开更多
Based on support vector machines, three modeling methods, i.e., white-box modeling, grey-box modeling and black-box modeling of ship manoeuvring motion in 4 degrees of freedom are investigated. With the whole-ship mat...Based on support vector machines, three modeling methods, i.e., white-box modeling, grey-box modeling and black-box modeling of ship manoeuvring motion in 4 degrees of freedom are investigated. With the whole-ship mathematical model for ship manoeuvring motion, in which the hydrodynamic coefficients are obtained from roll planar motion mechanism test, some zigzag tests and turning circle manoeuvres are simulated. In the white-box modeling and grey-box modeling, the training data taken every 5 s from the simulated 20°/20° zigzag test are used, while in the black-box modeling, the training data taken every 5 s from the simulated 15°/15°, 20°/20° zigzag tests and 15°, 25° turning manoeuvres are used; and the trained support vector machines are used to predict the whole 20°/20° zigzag test. Comparisons between the simulated and predicted 20°/20° zigzag tests show good predictive ability of the proposed methods. Besides, all mathematical models obtained by the proposed modeling methods are used to predict the 10°/10° zigzag test and 35° turning circle manoeuvre, and the predicted results are compared with those of simulation tests to demonstrate the good generalization performance of the mathematical models. Finally, the proposed modeling methods are analyzed and compared with each other in aspects of application conditions, prediction accuracy and computation speed. The appropriate modeling method can be chosen according to the intended use of the mathematical models and the available data needed for system identification.展开更多
A ship manoeuvring problem is solved using an algorithm built on fuzzy logic.The manoeuvring model for a design ship is coded in C++and the results are presented here.A bulk carrier is assumed as design ship for a new...A ship manoeuvring problem is solved using an algorithm built on fuzzy logic.The manoeuvring model for a design ship is coded in C++and the results are presented here.A bulk carrier is assumed as design ship for a newly setting up harbor along the east coast of India.The harbor mouth is 25 km away from the deep water zone.The approach channel is straight along the 22 km length.Laterally restricted and shallow waters are considered and their influences on hydrodynamic derivatives are discussed.Some sample problems are solved.Trajectories,ship heading,rudder angle,velocities and accelerations,of the moving vessel,are calculated and presented for clarity.The developed code is robust in the sense that any designer or user can easily interact with various input parameters to verify the outputs and their suitability for the design ship meant for a particular water front location.The results are validated using another algorithm built on PID which is discussed in brief.展开更多
基金The project supported by Beijing Institute of Spacecraft Overall Design
文摘The general principle of utilizing the BGK equation to simulate a macroscopic gas flow is illustrated. Two typical examples, i.e., a low-speed axisymmetric submerged jet and the Prandtl-Meyer expansion to a vacuum, are presented for validating the feasibility and accuracy of the BGK-equation simulation in continuum and non-continuum flow regimes. This approach is then used to simulate the exhaust plume formed by a small manoeuvre thruster of an artificial satellite in the outer space. The plume impingement on a flat surface perpendicular to the nozzle axis is also simulated by the same method. In the latter case the impingement force acting on the flat surface is calculated. When the flow reaches to the steady state the calculated impingement force is reasonably compared with the theoretical value of the nozzle thrust.
文摘Background: Intermittent Pringle manoeuvre resul- ted in less blood loss and better preservation of liver function when it was applied for fewer than 120 mi- nutes. The mechanism of better preservation of liver function under intermittent Pringle manoeuvre at molecular level remains unclear. Furthermore, the ultrastructural features in the liver with chronic di- seases under intermittent Pringle manoeuvre have not been studied. The aim of the study is to investigate the expression of stress genes and ultrastructural change of the liver under intermittent Pringle ma- noeuvre. Methods: From July 1995 to February 1998, 131 pa- tients underwent hepatectomy for liver tumours (61 patients without Pringle manoeuvre and 70 patients with intermittent Pringle manoeuvre). Twenty-five patients (15 with Pringle manoeuvre and 10 without Pringle manoeuvre) were included in the study of he- patic stress gene expression during hepatectomy. Twenty-two patients (18 patients with intermittent Pringle manoeuvre and four patients without Pringle manoeuvre) were randomly assigned for electron mi- croscopic examination. Results: For the expression of stress genes, both the heat shock genes (HSP 70A and HSC 70) and acute phase genes (TNF-α and interleukin-6) were detec- ted simultaneously in the patients with or without in- termittent Pringle manoeuvre. The patients under in- termittent Pringle manoeuvre had relatively higher mRNA levels of heat shock gene 70 family, which is related to intracellular repair and protection. Induc- tion of TNF-α and interleukin-6 genes, which con- tributed to ischaemia-reperfusion injury and posto- perative complication, was not found in the patients under intermittent Pringle manoeuvre. Under the e- lectron microscopy, the hepatic ultrastructure was well maintained under intermittent Pringle manoeu- vre whatever the liver status, even when the accumu- lated ischaemic duration was extended to 120 min. Conclusion: Intermittent Pringle manoeuvre induced relatively higher expression of heat shock genes, which are related to intracellular homeostasis, and is consistent with the well maintenance of liver ultra- structure.
基金supported by the National Natural Science Foundation of China (61901514)the Young Talent Program of Air Force Early Warning Academy (TJRC425311G11)。
文摘This paper proposes a parity recognition of blade number and manoeuvre intention classification algorithm of rotor target based on the convolutional neural network(CNN) using micro Doppler features. Firstly, the time-frequency spectrograms are acquired from the radar echo by the short-time Fourier transform.Secondly, based on the obtained spectrograms, a seven-layer CNN architecture is built to recognize the blade-number parity and classify the manoeuvre intention of the rotor target. The constructed architecture contains a leaky rectified linear unit and a dropout layer to accelerate the convergence of the architecture and avoid over-fitting. Finally, the spectrograms of the datasets are divided into three different ratios, i.e., 20%, 33% and 50%,and the cross validation is used to verify the effectiveness of the constructed CNN architecture. Simulation results show that, on the one hand, as the ratio of training data increases, the recognition accuracy of parity and manoeuvre intention is improved at the same signal-to-noise ratio(SNR);on the other hand, the proposed algorithm also has a strong robustness: the accuracy can still reach 90.72% with an SNR of – 6 dB.
文摘Quiescent Type of H. Rosen & Stage 2 of C.L. Romano et al. for Infected Non Union of Femur after K-nailing (Küntscher nailing) require no debridement & removal of nail and therefore can be treated by a single stage procedure. There are a few reports of treating aseptic non-union of femur by compression alone or compression distraction over nail by Ilizarov Technique. However, no case of Infected Non-Union femur being treated by Accordion Manoeuvre with Ilizarov over nail in situ (i.e. without exchange nailing) has been reported so far. Here, we are reporting a case of Infected Non-Union following K-nailing for a fracture shaft of femur in a 15-year-old female, who was treated by this technique as a single stage procedure. An Ilizarov frame was mounted on the femur with nail in situ followed by Accordion Manoeuvre. The fracture was healed in 5.6 months with two cycles of Accordion Manoeuvre followed by rhythmic compression. There was no recurrence of infection.
基金supported by the National Natural Science Foundation of China(No.82070965).
文摘Objective This study aimed to examine the association of primary open-angle glaucoma(POAG)with autonomic dysfunction by assessing the differences in systemic and ocular responses to an autonomic provocation test,the Valsalva manoeuvre(VM),between POAG patients and normal subjects.Methods Forty POAG and forty control subjects were subjected to the VM.Systemic and ocular parameters were measured at baseline,phase 2,and phase 4 of the VM(VM2 and VM4),where VM2 and VM4 are sympathetic and parasympathetic nervous activation states,respectively.Heart rate variability was used to assess the autonomic nervous activity,among which the high-frequency component(HF)and the low-frequency(LF)/HF ratio were used as indices of parasympathetic and sympathetic activation,respectively.Results POAG patients demonstrated higher sympathetic activation(LF/HF ratio median:2.17 vs.1.53,P=0.000)than controls at baseline and exhibited attenuated sympathetic and parasympathetic responses(a smaller change in LF/HF and HF values)during the VM than controls.During VM,the intraocular pressure(IOP),mean blood pressure(MAP),mean ocular perfusion pressure(MOPP),and the Schlemm’s canal area(SCAR)increased from baseline to VM2 and then decreased from VM2 to VM4 in both the POAG and control groups(all P<0.05).However,when we compared the changes above,the fluctuations in IOP,MAP,and MOPP were more pronounced in POAG than in controls(all P<0.05),while the changes in amplitudes of SCAR were smaller in POAG(P<0.05).Furthermore,from VM2 to VM4,the choroid thickness(ChT)in the POAG group was significantly decreased,while it was unchanged in normal subjects(P=0.258).A regression analysis showed a significant correlation of the baseline LF/HF with IOP change values(ΔIOP)from baseline to VM2 in POAG(R^(2)=0.147,P=0.014).Conclusion Patients with POAG showed more pronounced fluctuations in IOP,MAP,MOPP and ChT during the VM than controls.These reactions could be associated with autonomic dysfunction in POAG.
文摘Heart attack is an extremely urgent medical condition which may occur at any time and can affect anybody and means the failure of the pump function of the heart and it represents the condition which brings to death. The aim of this study is the training, which is the acquisition of knowledge, abilities and skills as a result of education and practice in a certain discipline and this project has been created to make as accessible to all as possible the information about the identification and treatment of heart attack. However, the key objective has been involving only laic blind subjects in the trial and theoretical-practical course to support vital functions （BLS （basic life support））, to demonstrate that in a state of emergency, like a heart attack, even a subject affected by visual impairment, if properly trained, can be very helpful and can contribute to save a life. Fifteen partially sighted and sightless executors have participated in this study. In order to evaluate learning objectives of the course, participants have completed a pre-course test to examine these areas： cognitive and emotional, motivational, theoretical-practical; while, at the end of the course, participants have completed a comment card about the course. At the end of this study it can be seen that blind subjects do not present any type of limitation in the learning and in the execution of BLS manoeuvres after an appropriate training.
文摘Cardiac Arrest (CA) is a major health problem, due to short and long-term sequel? and to associated mortality. Despite the improvement of out-of-hospital and in-hospital resuscitation manoeuvres, unexpected sudden fatal events occur. The authors reported the features of a series of sudden death (SD) cases where cardiopulmonary resuscitation (CPR) was performed. Files of 1053 medico-legal autopsies, from victims aged ≥18 years-old, were reviewed. Cardiac Arrest leading to Sudden Death were found in 477 cases (45.3%), but only 199 (42%) of these had been submitted to resuscitation manoeuvres. There was an elderly male predominance. Both non-cardiac and cardiac CA/SD causes were present, despite the higher coronary artery disease incidence. Both out-of-hospital and in-hospital events took place. Age, severity of the disease, comorbidities and predominance of out-of-hospital CA were obstacles to successful CPR, leading to SD. Knowing the population characteristics may help to improve Emergency Assistance.
基金financially supported by the National Natural Science Foundation of China(Grant No.51279106)the Special Research Fund for the Doctoral Program of Higher Education of China(Grant No.20110073110009)
文摘Based on support vector machines, three modeling methods, i.e., white-box modeling, grey-box modeling and black-box modeling of ship manoeuvring motion in 4 degrees of freedom are investigated. With the whole-ship mathematical model for ship manoeuvring motion, in which the hydrodynamic coefficients are obtained from roll planar motion mechanism test, some zigzag tests and turning circle manoeuvres are simulated. In the white-box modeling and grey-box modeling, the training data taken every 5 s from the simulated 20°/20° zigzag test are used, while in the black-box modeling, the training data taken every 5 s from the simulated 15°/15°, 20°/20° zigzag tests and 15°, 25° turning manoeuvres are used; and the trained support vector machines are used to predict the whole 20°/20° zigzag test. Comparisons between the simulated and predicted 20°/20° zigzag tests show good predictive ability of the proposed methods. Besides, all mathematical models obtained by the proposed modeling methods are used to predict the 10°/10° zigzag test and 35° turning circle manoeuvre, and the predicted results are compared with those of simulation tests to demonstrate the good generalization performance of the mathematical models. Finally, the proposed modeling methods are analyzed and compared with each other in aspects of application conditions, prediction accuracy and computation speed. The appropriate modeling method can be chosen according to the intended use of the mathematical models and the available data needed for system identification.
文摘A ship manoeuvring problem is solved using an algorithm built on fuzzy logic.The manoeuvring model for a design ship is coded in C++and the results are presented here.A bulk carrier is assumed as design ship for a newly setting up harbor along the east coast of India.The harbor mouth is 25 km away from the deep water zone.The approach channel is straight along the 22 km length.Laterally restricted and shallow waters are considered and their influences on hydrodynamic derivatives are discussed.Some sample problems are solved.Trajectories,ship heading,rudder angle,velocities and accelerations,of the moving vessel,are calculated and presented for clarity.The developed code is robust in the sense that any designer or user can easily interact with various input parameters to verify the outputs and their suitability for the design ship meant for a particular water front location.The results are validated using another algorithm built on PID which is discussed in brief.
