RESUMO
Objective To study the effect of the preset temperature,heating time and the spacing of radio frequency electrodes.Methods Fresh egg white was used to study the effects of heater spacing,temperature and heating time.Two electrodes were fixed to keep the needles perpendicular to the center of egg white confined on a square plate.Temperatures from 50 to 90℃ were tested with heating times of 60 and 120 seconds and electrode spac ings of 2.0,1.0,0.5 and 0.25 centimetres.The real-time temperature and the time to the appearance of a spindleshaped bridge between the electrodes was observed.The egg white's impedance and resistance,the lowest temperature of denaturation,and the mass (or volume) denatured at different time points were also observed.Results With an electrode spacing of 2 cm and the thermostat set at 63℃,the true electrode temperatures were 63.7 and 52.6℃,with the secondary electrode the cooler.Significant differences between the secondary electrode temperature and the preset temperature as well as the temperature between the primary and the secondary electrodes were observed.It was also found that different electrode spacing caused significant differences between the preset temperature and the primary as well as the secondary electrode temperature.Denaturation began at 56℃ with a spacing of 0.25 cm.At spacings of 0.25 and 0.50 cm,a spindle-shaped connection between the two electrodes was observed at temperatures above 70℃,but higher temperature was required at 1.00 and 2.00 cm.When the spacing was 0.25 cm and the preset temperature was 75℃,the denatured volume after 60 s of heating was 90.21+0.64 mm3.Heating for 120 s denatured 95.08+ 0.53 mm3 and two 60.s heatings 92.88+0.74 mm3,all significant differences.There were no significant differences in the resistance of the egg white before and after a single heating for 60 s,but after a single heating lasting 120 s it had increased significantly from 128.41+8.04 to 121.29±8.04 Ω.Conclusion Bipolar radio frequency heating can denature egg white.Higher temperature,longer heating and smaller electrode spacing heat more effectively.
RESUMO
BACKGROUND:The state of ischemic penumbra after cerebral infraction determines the final infarct volume. Decreased selective gene expression and protein synthesis, lactic acidosis and cytotoxic edema, salvage therapy of nerve cels, and continous regulation of neurovascular unit in the ischemic penumbra are areas of interest for recovery of neurological function. OBJECTIVE: Taking the neoangiogenesis process of post-infarction as the research point, to investigate the basic law of neovascularization with time and the effect of electroacupuncture intervention on proliferation of local blood vessels. METHODS: Ninety-six Wistar rats were randomly and evenly divided into model and electroacupuncture groups. The rat models of middle cerebral artery infarction were established by suture method. Immediately after modeling, the rats in the electroacupuncture group were given electrical stimulation (15 Hz, 1mA, 20 minutes) at the Renzhong (Du26) acupoint. The rats in the model group received similar procedures with the exception of no treatment. The angiogenesis was observed using double-immunofluorescence labeling for von Wilebrand Factor (vWF) and Ki-67 antibodies at 3, 6, 12, 24, 48 hours and 3, 7, 12 days after middle cerebral artery occlusion. RESULTS AND CONCLUSION:In the model group, vascular endothelial cel proliferation in the peri-infarct region was not observed at 3, 6 and 12 hours, occurred at 24 hours, increased at 48 hours, reached a maximum at 3 days, began to decrease at 7 days, and disappeared at 12 days after middle cerebral artery occlusion. In the electroacupuncture group, vascular endothelial cel proliferation in the peri-infarct region was not observed at 3 and 6 hours, occurred at 12 hours, increased at 24 and 48 hours, peaked at 3 days, began to decerase at 7 days, and disappeared at 12 days after middle cerebral artery occlusion. Compared with the model group, the time at which vascular endothelial cel proliferation started was earlier, and the number of proliferated vascular endothelial cels was greater in the electroacupuncture group. Vascular endothelial cel proliferation in the infarcted regions and contralateral hemisphere was not observed in either group at al designated time points. These results demonstrate that electroacupuncture intervention can improve the prognosis of cerebral infarction by promoting the proliferation of vascular endothelial cels in the peri-infarct region and advancing the time at which vascular endothelial cel proliferation started in rat models of middle cerebral artery occlusion.
RESUMO
BACKGROUND:Knee osteoarthritis is a chronic disease characterized as cartilage degeneration and hyperostosis to impact the soft tissues around the joints, thereby resulting in joint pain, and it can be aggravated and lead to joint deformity after weight-bearing. OBJECTIVE:On the basis of imaging parameters of knee osteoarthritis patients and normal controls, a model was established. And then, knee squatting movement was simulated on the model and stress data from the cartilage surface of patients and normal controls were colected and compared, thereby to obtain the stress characteristics of the cartilage surface in knee osteoarthritis patients. METHODS: There were 30 knee osteoarthritis patients and 30 healthy volunteers in the study. CT and MRI data from these participants were colected and analyzed using Mimics software and simpleware software to establish a model. Based on this model, cartilage-related stress data were harvested from knee osteoarthritis patients and healthy volunteers and compared to summarize the stress characteristics of the articular cartilage in patients with knee osteoarthritis. RESULTS AND CONCLUSION:In knee osteoarthritis patients, the stress on the cartilage surface from standing to squatting was increased in a nonlinear manner. During the process of squatting, the mediolateral stress was higher in the knee osteoarthritis patients than healthy controls (P 0.05). These findings indicate that the knee osteoarthritis musculoskeletal model and finite element model are established successfuly, and these models are closer to the real motion characteristics of the knee joints, based on which, quantitative biomechanical data of the knee can be provided for knee osteoarthritis treatment.