BACKGROUND： It has been shown that interleukin-1β（IL-1β） can induce fever by activating vascular endothelial cells and macrophages of the supraoptic crest to generate prostaglandin E2, which binds with receptors ...BACKGROUND： It has been shown that interleukin-1β（IL-1β） can induce fever by activating vascular endothelial cells and macrophages of the supraoptic crest to generate prostaglandin E2, which binds with receptors of the thermo-sensitive hypothalamic neurons. Lonicera japonica is one of the medicinal plants used widely in Asia for its antipyretic properties. However, these mechanisms have not yet been intensively studied. OBJECTIVE： To investigate the antipyretic effect and mechanisms of Lonicera japonica on IL-1β- induced febrile New Zealand rabbits by observing expression changes of E-type prostaglandin receptor-3 （EP3） mRNA in the preoptic anterior hypothalamus （POAH）. DESIGN： A randomized controlled study. SETTING： Electrophysiological Laboratory at the Department of Pathophysiology, Medical College of Jinan University; Department of Orthopaedics, First Hospital Affiliated to Medical College of Jinan University. MATERIALS： The experiment was performed from April to December 2005, using a total of 32 New Zealand white rabbits of both sexes, weighing 1.5 2.0 kg. All the animal experiments were performed according to the internationally accepted ethical guidelines. Lonicera japonica injection was purchased from Huanghe pharmaceutical factory of Xi＇an, China. IL-1βwas purchased from Sigma, USA. METHODS： A total of 32 rabbits were divided randomly into four groups： ① Normal saline （NS） control group;② Lonicerajaponica treatment group; ③ IL-1βtreatment group; and ④Lonicerajaponica plus IL-1βtreatment group. In the first 3 groups, the rabbits were given separate intravenous （i.v.） injections of l mL NS, l mL Lonicera japonica, and 100 ng IL-l β （dissolved in 0.9% NS without pyrogen）. In the Lonicerajaponica plus IL-1βgroup each rabbit was given i.v. injections of l mL NS and, 30 minutes later, 100 ng IL-1 β. MAIN OUTCOME MEASURES： Colonic temperature of each rabbit was measured at 0, 10, 20, 30, 40, 50, 60, and 70 minutes after injection and the maximum temperature rise （ A T） and the temperature response index after l hour （TRII） was calculated. Subsequently, in situ hybridization （ISH） was done with an ISH kit, EP3 mRNA expression in the POAH of all groups was measured （number of positive cells and average gray scale value）. RESULTS： A total of 32 rabbits were included in the result analysis, without any loss, （i） A T and TRII： there was no significant difference between the Lonicera japonica group and NS group （P 〉 0.05）. The IL-1β group was significantly greater compared to NS group （P 〈 0.01）. The Lonicera japonica plus IL-1β group was significantly less than the IL-1β group （P 〈 0.05）. ② In the NS and Lonicera japonica groups, the EP3 mRNA expression was negative （no coloration） or only weakly positive （only a few brown yellow particles in the cytoplasm cells could not be identified）. The number of positive cells and the average gray scale value were not significantly different between the two groups （P 〉 0.05）. In the IL-1β group, the number of positive cells was remarkably higher and the average gray scale value was lower than the NS group （P 〈 0.0 l）. In the Lonicera japonica plus IL-1β group, the number of positive cells was significantly less than the IL-1β group （P 〈 0.05）. However, the average gray scale value was greater than the IL-1β group （P 〈 0.05）. CONCLUSION： Lonicera japonica has obvious antipyretic effects on IL-1β-induced febrile rabbits and acts by inhibiting expression of EP3 mRNA in the POAH.展开更多
Based on the sensing mechanism of microsensor, a simulation model of a practical silicon beam resonator attached to an E-type round diaphragm and used for measuring concentrated force is established. The relationship ...Based on the sensing mechanism of microsensor, a simulation model of a practical silicon beam resonator attached to an E-type round diaphragm and used for measuring concentrated force is established. The relationship between the basic natural frequency of the beam resonator and the concentrated force is calculated, analyzed and investigated. As a microsensor FEM is used to study some important simulation results on the vibration features of the beam resonators. Based on the differential output signals, a set of optimum parameters of the proposed sensing unit is determined.展开更多
Purpose-Association of American railroads(AAR)standard automatic couplers are designed for much higher capacity than the normal operating loads.However,failure of knuckles and coupler bodies is still a common occurren...Purpose-Association of American railroads(AAR)standard automatic couplers are designed for much higher capacity than the normal operating loads.However,failure of knuckles and coupler bodies is still a common occurrence.Recent studies have shown that fatigue is the main reason behind such failures below the expected load.Moreover,knuckle failures occur more frequently than coupler body failures,which cause operational disruptions and also influence overall coupler life because of nonconforming contact between a new knuckle and an old coupler.In addition to new and old counterparts,undesired contact conditions are often the case with the new assembly due to casting-based manufacturing inaccuracies.Design/methodology/approach-A study is thus carried out in this paper to understand the variation of load transfer paths and its consequences caused by dimensional variability.A finite element model of an E-type coupler’s knuckle is developed and different possible contact conditions of the knuckle with the coupler head are simulated.Knuckles generally fail in pulling mode,during which the possible contacting elements of knuckle are pulling lugs,pin protector regions and pinholes.Due to dimensional variability,contact conditions may exist where an individual or a combination of these elements are in contact.Findings-Simulation results indicate that under regular operational conditions,having only the pulling lugs in contact reduces the risk of knuckle failure and maintains assembly integrity even if the knuckle fails.However,under extreme loading conditions,the safest scenario is when both pulling lugs and pin protector regions are in contact.Originality/value-These findings are believed to assist in defining the dimensional variability limits to ensure the desired contacts between the mating surfaces of the knuckle and coupler body of railway couplers of AAR type.This work contributes to understanding implications of dimensional variability in the railway couplers.The insight presented are useful in design,manufacturing and maintenance of railway coupler’s knuckle.展开更多
基金Grants from the National Natural Science Foundation of China, No. 39600061National Administration of Traditional Chinese Medicine, No.2003LHR13+3 种基金Medical Science Foundation of Guangdong Province, No. A2004327, A2006334the Natural Science Foundation of Guangdong, No. 04010443, 06105246 Administration Bureau of Traditional Chinese Medicine of Guangdong Province, No.1040074Technology Bureau of Guangzhou, No. 2007J1-C0041
文摘BACKGROUND： It has been shown that interleukin-1β（IL-1β） can induce fever by activating vascular endothelial cells and macrophages of the supraoptic crest to generate prostaglandin E2, which binds with receptors of the thermo-sensitive hypothalamic neurons. Lonicera japonica is one of the medicinal plants used widely in Asia for its antipyretic properties. However, these mechanisms have not yet been intensively studied. OBJECTIVE： To investigate the antipyretic effect and mechanisms of Lonicera japonica on IL-1β- induced febrile New Zealand rabbits by observing expression changes of E-type prostaglandin receptor-3 （EP3） mRNA in the preoptic anterior hypothalamus （POAH）. DESIGN： A randomized controlled study. SETTING： Electrophysiological Laboratory at the Department of Pathophysiology, Medical College of Jinan University; Department of Orthopaedics, First Hospital Affiliated to Medical College of Jinan University. MATERIALS： The experiment was performed from April to December 2005, using a total of 32 New Zealand white rabbits of both sexes, weighing 1.5 2.0 kg. All the animal experiments were performed according to the internationally accepted ethical guidelines. Lonicera japonica injection was purchased from Huanghe pharmaceutical factory of Xi＇an, China. IL-1βwas purchased from Sigma, USA. METHODS： A total of 32 rabbits were divided randomly into four groups： ① Normal saline （NS） control group;② Lonicerajaponica treatment group; ③ IL-1βtreatment group; and ④Lonicerajaponica plus IL-1βtreatment group. In the first 3 groups, the rabbits were given separate intravenous （i.v.） injections of l mL NS, l mL Lonicera japonica, and 100 ng IL-l β （dissolved in 0.9% NS without pyrogen）. In the Lonicerajaponica plus IL-1βgroup each rabbit was given i.v. injections of l mL NS and, 30 minutes later, 100 ng IL-1 β. MAIN OUTCOME MEASURES： Colonic temperature of each rabbit was measured at 0, 10, 20, 30, 40, 50, 60, and 70 minutes after injection and the maximum temperature rise （ A T） and the temperature response index after l hour （TRII） was calculated. Subsequently, in situ hybridization （ISH） was done with an ISH kit, EP3 mRNA expression in the POAH of all groups was measured （number of positive cells and average gray scale value）. RESULTS： A total of 32 rabbits were included in the result analysis, without any loss, （i） A T and TRII： there was no significant difference between the Lonicera japonica group and NS group （P 〉 0.05）. The IL-1β group was significantly greater compared to NS group （P 〈 0.01）. The Lonicera japonica plus IL-1β group was significantly less than the IL-1β group （P 〈 0.05）. ② In the NS and Lonicera japonica groups, the EP3 mRNA expression was negative （no coloration） or only weakly positive （only a few brown yellow particles in the cytoplasm cells could not be identified）. The number of positive cells and the average gray scale value were not significantly different between the two groups （P 〉 0.05）. In the IL-1β group, the number of positive cells was remarkably higher and the average gray scale value was lower than the NS group （P 〈 0.0 l）. In the Lonicera japonica plus IL-1β group, the number of positive cells was significantly less than the IL-1β group （P 〈 0.05）. However, the average gray scale value was greater than the IL-1β group （P 〈 0.05）. CONCLUSION： Lonicera japonica has obvious antipyretic effects on IL-1β-induced febrile rabbits and acts by inhibiting expression of EP3 mRNA in the POAH.
文摘Based on the sensing mechanism of microsensor, a simulation model of a practical silicon beam resonator attached to an E-type round diaphragm and used for measuring concentrated force is established. The relationship between the basic natural frequency of the beam resonator and the concentrated force is calculated, analyzed and investigated. As a microsensor FEM is used to study some important simulation results on the vibration features of the beam resonators. Based on the differential output signals, a set of optimum parameters of the proposed sensing unit is determined.
文摘Purpose-Association of American railroads(AAR)standard automatic couplers are designed for much higher capacity than the normal operating loads.However,failure of knuckles and coupler bodies is still a common occurrence.Recent studies have shown that fatigue is the main reason behind such failures below the expected load.Moreover,knuckle failures occur more frequently than coupler body failures,which cause operational disruptions and also influence overall coupler life because of nonconforming contact between a new knuckle and an old coupler.In addition to new and old counterparts,undesired contact conditions are often the case with the new assembly due to casting-based manufacturing inaccuracies.Design/methodology/approach-A study is thus carried out in this paper to understand the variation of load transfer paths and its consequences caused by dimensional variability.A finite element model of an E-type coupler’s knuckle is developed and different possible contact conditions of the knuckle with the coupler head are simulated.Knuckles generally fail in pulling mode,during which the possible contacting elements of knuckle are pulling lugs,pin protector regions and pinholes.Due to dimensional variability,contact conditions may exist where an individual or a combination of these elements are in contact.Findings-Simulation results indicate that under regular operational conditions,having only the pulling lugs in contact reduces the risk of knuckle failure and maintains assembly integrity even if the knuckle fails.However,under extreme loading conditions,the safest scenario is when both pulling lugs and pin protector regions are in contact.Originality/value-These findings are believed to assist in defining the dimensional variability limits to ensure the desired contacts between the mating surfaces of the knuckle and coupler body of railway couplers of AAR type.This work contributes to understanding implications of dimensional variability in the railway couplers.The insight presented are useful in design,manufacturing and maintenance of railway coupler’s knuckle.
