BACKGROUND: Presyrinx state of spinal cord can reflect the initial lesion of syringomyelia (SM). The early trials has proved that ischamia and edema are main pathological changes of presyrinx state. OBJECTIVE: To esta...BACKGROUND: Presyrinx state of spinal cord can reflect the initial lesion of syringomyelia (SM). The early trials has proved that ischamia and edema are main pathological changes of presyrinx state. OBJECTIVE: To establish SM model of rabbits for investigating the relationship between changes of morphous and function of blood-spinal cord barrier and the edema degree, histological changes in presyrinx state of SM, and to explore the mechanism of the presyrinx state of SM. DESIGN: Randomized controlled animal experiment. SETTING: Department of Neurosurgery, Fourth Hospital, Heibei Medical University. MATERIALS: Sixty Chinese healthy white rabbits, aged 3.5-4.5 months, weighing 1.5-2.0 kg, were provided by Experimental Animal Center of Hebei Medical University [certification: (SYXK(Ji)2003-0026)]. Evan's blue (EB) and dimethylformamide (DMF) were purchased from Jingmei Biotech Co., Ltd. RM2125 paraffin section cutter (Leica Company, Japan), H-7500 transmission electron microscope (Hitachi Company, Japan), PM-20 light microscope photograph system (Olympus Company, Japan). METHODS: The experiment was carried out in the Laboratory of Neurosurgery Department, Second Hospital of Hebei Medical University from January to June 2006. ① All the rabbits were randomly divided into two groups: model group (n =40), control group (n =20). Rabbits in two groups were divided into five subgroups once again at five time points (1st, 3rd, 7th, 14th, 21st days, n =8 and n =4 at each time point in the model group and control group, respectively). Under ketamine anesthesia, 0.6 mL Kaolin solution (250 g/L, 37 ℃) was injected into the cisterna magna of rabbits in model group, while 0.6 mL physiological saline (37 ℃) was injected into the rabbits of control group. ② On the 1st, 3rd, 7th, 14th, 21st days after kaolin injection, cervical cord samples were harvested after sacrifice of animal. Quantitative analysis on the function of blood-spinal cord barrier was performed by Evan's blue technique. Water content of spinal cord was measured by dry-wet weighing technique. Samples were fixed in 40 g/L paraform for haematoxylin and eosin staining. Pathological and ultramicrostructural observation was carried out under a light microscope and H-7500 electron microscope, respectively. ③ The comparison of measurement data was performed with analysis of variance. MAIN OUTCOME MEASURES: The changes of water content, Evan's blue content and pathology in upper cervical cord of presyrinx state at different time points. RESULTS: All the 60 rabbits were involved in the result analysis. ① Ultramicrostructural observation: During the whole process of occurrence and development of presyrinx state of spinal cord, no obvious morphological changes of blood-spinal cord barrier were found. Microvascular endothelial cells were in integrity in morphology, basal membrane was continuous and smooth, and the structure of tight junction was not destructed remarkably. ②Water content of spinal cord: Compared with control group, the water content of spinal cord was increased on the 1st day [(68.35±0.7)% vs.(66.51±0.32)%, F =7.387, P =0.026] after kaolin injection, more prominent on the 3rd day [(72.70±0.88)%, F =123.48, P =0.000], reached its peak on the 7th-14th day [(72.92±0.86)%, F =135.94, P =0.000; (72.18±0.55)%, F =28.18, P =0.001], and was declined slowly after 21 days[(70.03±0.77)%,F =11.51, P =0.009], but it was still higher than that of control group [(65.98±0.56)%, F = 11.51, P =0.009].③ Evan's blue content in spinal cord tissue: It started to rise on the 3rd day after operation [(2.79±0.42) mg/L, F =61.35, P =0.000], reached its peak on the 7th day [(3.53±0.45) mg/L, F =528.35, P =0.000], and kept this high level till the 14th day [(3.45± 0.35) mg/L, F =326.57, P =0.000]. It decreased on the 21st day [(3.36±0.27) mg/L], but was still higher than normal level[(1.69±0.16)mg/L,F = 58.63,P =0.000]. ④ Neurologic function score: The neurologic function score of rabbits in the model group was close to that in the control group preoperatively and on the postoperative 1st and 3rd days (F =2.667, P =0.141);Abnormal nerve function appeared on the postoperative 7th day (F =32.667, P =0.00), and the neurologic function scores were gradually decreased with the elongation of time. The neurologic function scores in the model group were significantly lower than those in the control group on the postoperative 14th and 21st days (F =42.667, 34.571,P =0.00). CONCLUSION: Under the presyrinx state of spinal cord of experimental rabbits, the destruction of blood-spinal cord barrier of spinal cord and spinal edema co-exist with the same changing tendency. Although morphological integrity of blood-spinal cord barrier is kept, the function of blood-spinal cord barrier was destroyed in the early stage and permeability is increased. This functional disorder plays an important role in the occurrence and development of presyrinx state of SM.展开更多
In order to cultivate excellent clinical medical talents with a solid foundation, strong literacy, refined skills, excellent communication abilities, innovative thinking, and a strong focus on practicality, functional...In order to cultivate excellent clinical medical talents with a solid foundation, strong literacy, refined skills, excellent communication abilities, innovative thinking, and a strong focus on practicality, functional experiments have undergone a series of reforms in areas such as constructing new curriculum systems, improving teaching content, updating teaching equipment, introducing new teaching models, and enhancing teaching evaluation systems.展开更多
Medical Functional Experiment Science, a bridge between basic medicine and clinical medicine, integrates classical experimental teaching contents of three courses including physiology, pathophysiology and pharmacology...Medical Functional Experiment Science, a bridge between basic medicine and clinical medicine, integrates classical experimental teaching contents of three courses including physiology, pathophysiology and pharmacology. This course not only helps students to verify and reinforce theoretical knowledge, but also cultivates their capability of scientific thinking to discover and solve problems. Based on the characteristics of international students and current situation of the teaching platform in the laboratory at Yangtze University, this paper discusses a series of problems in the Medical Functional Experiment Science teaching for international students and puts forward some measures for teaching reform including optimizing experimental content, innovating experimental teaching methods and establishing effective experimental evaluation mode, in order to cultivate more international medical students with innovative ability.展开更多
In this paper the semi-analytical analyses of the flexible cantilever tapered functionally graded beam under combined inclined end loading and intermediate loading are studied.In order to derive the fully non-linear e...In this paper the semi-analytical analyses of the flexible cantilever tapered functionally graded beam under combined inclined end loading and intermediate loading are studied.In order to derive the fully non-linear equations governing the non-linear deformation,a curvilinear coordinate system is introduced.A general non-linear second order differential equation that governs the shape of a deflected beam is derived based on the geometric nonlinearities,infinitesimal local displacements and local rotation concepts with remarkable physical properties of functionally graded materials.The solutions obtained from semi-analytical methods are numerically compared with the existing elliptic integral solution for the case of a flexible uniform cantilever functionally graded beam.The effects of taper ratio,inclined end load angle and material property gradient on large deflection of the beam are evaluated.The Adomian decomposition method will be useful toward the design of tapered functionally graded compliant mechanisms driven by smart actuators.展开更多
In this paper, we introduce a non-linear torque control for an interior permanent-magnet synchronous motor (IPMSM). The nonlinear control is based on a Control Lyapunov Function (CLF) technique. The proposed stabilizi...In this paper, we introduce a non-linear torque control for an interior permanent-magnet synchronous motor (IPMSM). The nonlinear control is based on a Control Lyapunov Function (CLF) technique. The proposed stabilizing feedback law for the IPMSM drive is a damping control method and is shown to be globally asymptotically stable. The CLF method takes the system nonlinearities into account in the control system design stage. Such nonlinearities are due to the cross coupling between the q and the q currents in addition to the system parameters like the inductances and the flux linkages. The complete IPMSM drive incorporating the proposed CLF has been successfully simulated in a plant model for both motor and inverter. The performance of the proposed drive is investigated in simulation at different operating conditions. It is found that the proposed control technique provides a good torque control performance for the IPMSM drive ensuring the global stability. In later work, we are planning to investigate other phenomena such as magnetic saturation, nonlinear loads, mechanical friction and flexibilities.展开更多
A lot of tests on ice forces on vertical cylindrical piles are conducted in the ice basin of ice laboratory in Tianjin University to identify the characteristics of ice forces on fixed platforms in the Bohai Gulf. A f...A lot of tests on ice forces on vertical cylindrical piles are conducted in the ice basin of ice laboratory in Tianjin University to identify the characteristics of ice forces on fixed platforms in the Bohai Gulf. A function of ice forces is simplified on basis of test data, and the characteristics of the ice forces including the amplitude of the force and the breaking frequency of the ice sheet is detailed by use of the Fast-Fourier-Transform method, The results show that the ice breaking frequency presents a linear relationship with the ratio of ice moving velocity to ice thickness at low velocities. At high velocities, the frequency remains constant with the increase of the ratio of ice moving velocity to ice thickness. These conclusions are compared those published in literature.展开更多
The effects of the polarization potential serve to model spectra of alkaline atoms. These effects have been known for a long time and notably explained by the physicist Max Born (1926). The experimental knowledge of t...The effects of the polarization potential serve to model spectra of alkaline atoms. These effects have been known for a long time and notably explained by the physicist Max Born (1926). The experimental knowledge of these alkaline spectra enables us to specify the values of these quantum defects. A simple code is used to calculate two quantum defects for which <em>δ<sub>l</sub></em><sub> </sub>can be distinguished as: <em>δ<sub>s</sub></em> <em>l</em> = 0 and <em>δ<sub>p</sub></em> <em>l</em> = 1. On the theoretical part, it is possible to have an analytical expression for these quantum defects <em>δ<sub>l</sub></em>. A second code gives the correct wave functions modified by the quantum defects <em>δ<sub>l</sub></em> with the condition for the principal number: <em>n</em><sub><span style="white-space:nowrap;"><span style="white-space:nowrap;">*</span></span></sub> = <em>n</em> – <em>δ</em><sub><em>l</em></sub> ≥ 1. It is well known that <em>δ</em><sub><em>l</em></sub> → 0 when the kinetic momentum <em>l</em> ≥ 4, and for such momenta the spectra turns out to be hydrogenic. Modern software such as Mathematica, allows us to efficiently generate the polynomes defining wave functions with fractional quantum numbers. This leads to a good theoretical representation of these wave functions. To get numerically the quantum defects, a simple code is given to obtain these quantities when the levels assigned to a transition are known. Then, the quantum defects are inserted into the arguments of the correct modified wave functions for the outer electron of an atom or ion undergoing the short range polarization potential.展开更多
文摘BACKGROUND: Presyrinx state of spinal cord can reflect the initial lesion of syringomyelia (SM). The early trials has proved that ischamia and edema are main pathological changes of presyrinx state. OBJECTIVE: To establish SM model of rabbits for investigating the relationship between changes of morphous and function of blood-spinal cord barrier and the edema degree, histological changes in presyrinx state of SM, and to explore the mechanism of the presyrinx state of SM. DESIGN: Randomized controlled animal experiment. SETTING: Department of Neurosurgery, Fourth Hospital, Heibei Medical University. MATERIALS: Sixty Chinese healthy white rabbits, aged 3.5-4.5 months, weighing 1.5-2.0 kg, were provided by Experimental Animal Center of Hebei Medical University [certification: (SYXK(Ji)2003-0026)]. Evan's blue (EB) and dimethylformamide (DMF) were purchased from Jingmei Biotech Co., Ltd. RM2125 paraffin section cutter (Leica Company, Japan), H-7500 transmission electron microscope (Hitachi Company, Japan), PM-20 light microscope photograph system (Olympus Company, Japan). METHODS: The experiment was carried out in the Laboratory of Neurosurgery Department, Second Hospital of Hebei Medical University from January to June 2006. ① All the rabbits were randomly divided into two groups: model group (n =40), control group (n =20). Rabbits in two groups were divided into five subgroups once again at five time points (1st, 3rd, 7th, 14th, 21st days, n =8 and n =4 at each time point in the model group and control group, respectively). Under ketamine anesthesia, 0.6 mL Kaolin solution (250 g/L, 37 ℃) was injected into the cisterna magna of rabbits in model group, while 0.6 mL physiological saline (37 ℃) was injected into the rabbits of control group. ② On the 1st, 3rd, 7th, 14th, 21st days after kaolin injection, cervical cord samples were harvested after sacrifice of animal. Quantitative analysis on the function of blood-spinal cord barrier was performed by Evan's blue technique. Water content of spinal cord was measured by dry-wet weighing technique. Samples were fixed in 40 g/L paraform for haematoxylin and eosin staining. Pathological and ultramicrostructural observation was carried out under a light microscope and H-7500 electron microscope, respectively. ③ The comparison of measurement data was performed with analysis of variance. MAIN OUTCOME MEASURES: The changes of water content, Evan's blue content and pathology in upper cervical cord of presyrinx state at different time points. RESULTS: All the 60 rabbits were involved in the result analysis. ① Ultramicrostructural observation: During the whole process of occurrence and development of presyrinx state of spinal cord, no obvious morphological changes of blood-spinal cord barrier were found. Microvascular endothelial cells were in integrity in morphology, basal membrane was continuous and smooth, and the structure of tight junction was not destructed remarkably. ②Water content of spinal cord: Compared with control group, the water content of spinal cord was increased on the 1st day [(68.35±0.7)% vs.(66.51±0.32)%, F =7.387, P =0.026] after kaolin injection, more prominent on the 3rd day [(72.70±0.88)%, F =123.48, P =0.000], reached its peak on the 7th-14th day [(72.92±0.86)%, F =135.94, P =0.000; (72.18±0.55)%, F =28.18, P =0.001], and was declined slowly after 21 days[(70.03±0.77)%,F =11.51, P =0.009], but it was still higher than that of control group [(65.98±0.56)%, F = 11.51, P =0.009].③ Evan's blue content in spinal cord tissue: It started to rise on the 3rd day after operation [(2.79±0.42) mg/L, F =61.35, P =0.000], reached its peak on the 7th day [(3.53±0.45) mg/L, F =528.35, P =0.000], and kept this high level till the 14th day [(3.45± 0.35) mg/L, F =326.57, P =0.000]. It decreased on the 21st day [(3.36±0.27) mg/L], but was still higher than normal level[(1.69±0.16)mg/L,F = 58.63,P =0.000]. ④ Neurologic function score: The neurologic function score of rabbits in the model group was close to that in the control group preoperatively and on the postoperative 1st and 3rd days (F =2.667, P =0.141);Abnormal nerve function appeared on the postoperative 7th day (F =32.667, P =0.00), and the neurologic function scores were gradually decreased with the elongation of time. The neurologic function scores in the model group were significantly lower than those in the control group on the postoperative 14th and 21st days (F =42.667, 34.571,P =0.00). CONCLUSION: Under the presyrinx state of spinal cord of experimental rabbits, the destruction of blood-spinal cord barrier of spinal cord and spinal edema co-exist with the same changing tendency. Although morphological integrity of blood-spinal cord barrier is kept, the function of blood-spinal cord barrier was destroyed in the early stage and permeability is increased. This functional disorder plays an important role in the occurrence and development of presyrinx state of SM.
文摘In order to cultivate excellent clinical medical talents with a solid foundation, strong literacy, refined skills, excellent communication abilities, innovative thinking, and a strong focus on practicality, functional experiments have undergone a series of reforms in areas such as constructing new curriculum systems, improving teaching content, updating teaching equipment, introducing new teaching models, and enhancing teaching evaluation systems.
文摘Medical Functional Experiment Science, a bridge between basic medicine and clinical medicine, integrates classical experimental teaching contents of three courses including physiology, pathophysiology and pharmacology. This course not only helps students to verify and reinforce theoretical knowledge, but also cultivates their capability of scientific thinking to discover and solve problems. Based on the characteristics of international students and current situation of the teaching platform in the laboratory at Yangtze University, this paper discusses a series of problems in the Medical Functional Experiment Science teaching for international students and puts forward some measures for teaching reform including optimizing experimental content, innovating experimental teaching methods and establishing effective experimental evaluation mode, in order to cultivate more international medical students with innovative ability.
文摘In this paper the semi-analytical analyses of the flexible cantilever tapered functionally graded beam under combined inclined end loading and intermediate loading are studied.In order to derive the fully non-linear equations governing the non-linear deformation,a curvilinear coordinate system is introduced.A general non-linear second order differential equation that governs the shape of a deflected beam is derived based on the geometric nonlinearities,infinitesimal local displacements and local rotation concepts with remarkable physical properties of functionally graded materials.The solutions obtained from semi-analytical methods are numerically compared with the existing elliptic integral solution for the case of a flexible uniform cantilever functionally graded beam.The effects of taper ratio,inclined end load angle and material property gradient on large deflection of the beam are evaluated.The Adomian decomposition method will be useful toward the design of tapered functionally graded compliant mechanisms driven by smart actuators.
文摘In this paper, we introduce a non-linear torque control for an interior permanent-magnet synchronous motor (IPMSM). The nonlinear control is based on a Control Lyapunov Function (CLF) technique. The proposed stabilizing feedback law for the IPMSM drive is a damping control method and is shown to be globally asymptotically stable. The CLF method takes the system nonlinearities into account in the control system design stage. Such nonlinearities are due to the cross coupling between the q and the q currents in addition to the system parameters like the inductances and the flux linkages. The complete IPMSM drive incorporating the proposed CLF has been successfully simulated in a plant model for both motor and inverter. The performance of the proposed drive is investigated in simulation at different operating conditions. It is found that the proposed control technique provides a good torque control performance for the IPMSM drive ensuring the global stability. In later work, we are planning to investigate other phenomena such as magnetic saturation, nonlinear loads, mechanical friction and flexibilities.
基金This project is financially supported by the National Natural Science Foundation of China (Grant No. 59739170)
文摘A lot of tests on ice forces on vertical cylindrical piles are conducted in the ice basin of ice laboratory in Tianjin University to identify the characteristics of ice forces on fixed platforms in the Bohai Gulf. A function of ice forces is simplified on basis of test data, and the characteristics of the ice forces including the amplitude of the force and the breaking frequency of the ice sheet is detailed by use of the Fast-Fourier-Transform method, The results show that the ice breaking frequency presents a linear relationship with the ratio of ice moving velocity to ice thickness at low velocities. At high velocities, the frequency remains constant with the increase of the ratio of ice moving velocity to ice thickness. These conclusions are compared those published in literature.
文摘The effects of the polarization potential serve to model spectra of alkaline atoms. These effects have been known for a long time and notably explained by the physicist Max Born (1926). The experimental knowledge of these alkaline spectra enables us to specify the values of these quantum defects. A simple code is used to calculate two quantum defects for which <em>δ<sub>l</sub></em><sub> </sub>can be distinguished as: <em>δ<sub>s</sub></em> <em>l</em> = 0 and <em>δ<sub>p</sub></em> <em>l</em> = 1. On the theoretical part, it is possible to have an analytical expression for these quantum defects <em>δ<sub>l</sub></em>. A second code gives the correct wave functions modified by the quantum defects <em>δ<sub>l</sub></em> with the condition for the principal number: <em>n</em><sub><span style="white-space:nowrap;"><span style="white-space:nowrap;">*</span></span></sub> = <em>n</em> – <em>δ</em><sub><em>l</em></sub> ≥ 1. It is well known that <em>δ</em><sub><em>l</em></sub> → 0 when the kinetic momentum <em>l</em> ≥ 4, and for such momenta the spectra turns out to be hydrogenic. Modern software such as Mathematica, allows us to efficiently generate the polynomes defining wave functions with fractional quantum numbers. This leads to a good theoretical representation of these wave functions. To get numerically the quantum defects, a simple code is given to obtain these quantities when the levels assigned to a transition are known. Then, the quantum defects are inserted into the arguments of the correct modified wave functions for the outer electron of an atom or ion undergoing the short range polarization potential.
