ABSTRACT
Objective To study a quantitative indicator for measuring the similarity between blood pressure waveforms and its application in the analysis on the simulated blood pressure waveform for pulsatile flow simulation system.Methods Based on the past similarity measurement algorithm and the known feature of blood pressure waveforms, the weighted average algorithm was presented in this paper, which possessed advantages of both global matching and partial matching by integrating the correlation coefficient with the characteristic parameter algorithm, and calculating similarity degrees through overall and partial waveform.Results The weighted average algorithm was proved to be more suitable for the analysis on the blood pressure waveform similarity compared with the angle cosine method, average absolute deviation method, and numeric similarity coefficient method.Conclusions The weighted average algorithm showed excellent ability in calculating the similarity degree between different waveforms, or in comparing the performance with different pulsatile flow simulation systems, and it could be applied to other physiological waveforms with further improvement.
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Objective To investigate the changes of bone mineral density (BMD) and biomechanical properties of the femur after ipsilateral tibia fracture in rats, and its relationship with the tibia fracture union. Methods Forty 3-month-old female SD rats were divided into 2 groups randomly and evenly: the surgery group and the control group. The surgery group received middle shaft fracture and fixation surgery on the right tibia. BMD of the right femur was measured both before the surgery and at 2nd, 4th, 6th, 8th, 10th, 12th week after the surgery, respectively. Ten rats in the surgery group and ten rats in the control group were executed at 6th and 12th week after the surgery, respectively, to test the biomechanical properties of their right tibia and femur. Results The radiological union rate and mechanical union rate of the tibia were 50% and 70%, respectively, at 6th week after the surgery, and those at 12th week after the surgery were both 100%. At 2nd, 4th, 6th, 8th week after the surgery, BMD of the right femur in the surgery group was significantly lower than that in the control group (P<0.05). Compared with the control group, there was no statistical difference in BMD of the right femur at 10th, 12th week after the surgery. Biomechanical properties of the right tibia and femur at 6th week after the surgery showed obviously worse than those at 12th week after the surgery (P<0.05). Analysis showed that the fracture union was highly related with mechanical properties of the tibia (P<0.01), which was also highly related with BMD and mechanical properties of the femur (P<0.001). Conclusions In the early stage of tibia fracture, disuse osteoporosis might occur due to the decrease of BMD and worse mechanical properties in the ipsilateral femur, but as the tibia fracture united, BMD and biomechanical properties of the femur became normal again.
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Objective To study the flow field of a new vascular bioreactor with small diameter at different operating conditions. Method To investigate the flow field of a new vascular bioreactor with small diameter under three operating conditions by numerical simulation: outer box rotating, inner box rotating and both inner box and outer box rotating. A comparison of parameters such as flow velocity and shear stress was made. Results The culture medium in the bioreactor rotated with the inner box and outer box, and the velocity was uniformly distributed; the bioreactor could therefore provide a low shear stress environment that is nondestructive for the cells in the medium; the shear stress in bioreactor had a quadratic function relation with the rotation rate. Conclusions This bioreactor could provide a good culture environment for vascular tissue regeneration, and this study provided theoretical basis for the experimental research of bioreactors.
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OBJECT@#To obtain values of normal human lung and diffuse pathological changes, in order to provide a simple and convenient diagnostic method for measuring human visceral organs in the autopsy of pathology and forensic pathology.@*METHODS@#The exact mass, volume and density of normal and pathological lung were synchronously measured with the intelligentized volume-densimeter made by authors.@*RESULTS@#The date-base about the volume and density of human lung with different races were established for anatomy, anthropology and biodynamics. In two cases of over-load in circulation and water toxicosis, the severe lung edema was proved with the scale of lung density, which was atypical edema in the lung tissue.@*CONCLUSION@#Measurement of visceral organs in the autopsy can assist to an integrative pathological diagnosis.