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ObjectiveTo investigate a foodborne disease outbreak and identify the pathogenic factors in order to prevent the occurrence of similar incidents. MethodsEpidemiological study， on-site food hygiene investigation， and laboratory testing were used to analyze the cause of outbreak in Company A. ResultsA total of 24 confirmed cases were screened out. The major clinical symptoms were diarrhea （100.0%）， stomachache （100.0%）， and vomiting （41.7%）. Samples from 24 patients were tested positive for Vibrio parahaemolyticus， and were homologous by Pulsed field gel electrophoresis （PFGE） phylogenetic study. According to the result of case-control study， eating glass noodles salad at the dinner and supper on July 16th， 2019 was the risk factor （OR=15.71，95%CI：1.90‒129.71）. ConclusionThis foodborne disease outbreak was caused by glass noodles salad cross contaminated with Vibrio parahaemolyticus.
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BACKGROUND:Three dimensional finite element analysis is widely used in orthopedics, but research in the knee flexion movement is not much. OBJECTIVE:To analyze biomechanical properties of knee flexion using finite element analysis.METHODS:Three dimensional finite element models and models of knee flexion at 30 degrees, 60 degrees and 120 degrees were established. Femoral forward movement, femur inward movement, tibia internal rotation and tibia vara were analyzed at different flexion angles. RESULTS AND CONCLUSION:(1) When knee flexion was at 30 degrees, 60 degrees and 120 degrees, the femur had backward movement. The backward movement value was larger at 60 degrees than at 30 and 120 degrees (P0.05). (2) The femur had outward movement at 30 degrees, and inward movement at 120 degrees. The inward movement value was significantly larger at 120 degrees than at 30 and 60 degrees (P0.05). (3) Tibia internal rotation was not significantly different at 30, 60 and 120 degrees of flexion (P>0.05). (4) Tibia vara was found at 30, 60 and 120 degrees of flexion, but the tibia vara was not obvious at 120 degrees. The tibia vara was maximum at 60 degrees, and significantly higher than that at 120 degrees (P0.05). (5) These findings verify that backward movement was most obvious at 60 degrees. Femur inward movement was most large at 120 degrees. Tibia internal rotation was noticeable at 30 and 120 degrees. Tibia vara was remarkable at 60 degrees.
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BACKGROUND:There are studies on three-dimensional finite element analysis of total knee replacement, but few research concerns contact pressure and contact area inside and outside polyethylene liner of fixed prosthesis and rotating platform prosthesis in total knee replacement. OBJECTIVE:To explore the contact pressure and contact area inside and outside polyethylene liner of fixed platform prosthesis and rotating platform prosthesis in total knee replacement. METHODS:We established three-dimensional finite element models of fixed platform prosthesis and rotating platform prosthesis in total knee replacement and compared contact pressure and contact area inside and outside polyethylene liner of fixed platform prosthesis and rotating platform prosthesis in total knee replacement. RESULTS AND CONCLUSION:The peak contact pressure inside and outside polyethylene liner of fixed platform prosthesis and rotating platform prosthesis in total knee replacement was minimum at 0° of genuflex. The peak contact pressure inside polyethylene liner was higher than that outside polyethylene liner of fixed platform prosthesis and rotating platform prosthesis in total knee replacement at 0°-90° of genuflex (P<0.05). The peak contact pressure inside and outside polyethylene liner of fixed platform prosthesis was higher than that of rotating platform prosthesis in total knee replacement at 60°-120° of genuflex (P<0.05). The contact area inside and outside polyethylene liner of fixed platform prosthesis and rotating platform prosthesis in total knee replacement was maximum at 0° of genuflex. The contact area inside polyethylene liner of fixed platform prosthesis in total knee replacement was lower than that of outside at 0°-30° of genuflex (P<0.05). The contact area inside polyethylene liner of fixed platform prosthesis in total knee replacement was lower than that of outside at 0°-90° of genuflex (P<0.05). The contact area inside and outside polyethylene liner of fixed platform prosthesis was lower than that of rotating platform prosthesis in total knee replacement at 30°-120° of genuflex (P<0.05). These results suggested that peak contact pressure inside polyethylene liner of fixed and rotating platform prostheses was higher than that outside in total knee replacement, and the inside contact area was lower than that of outside. Inside and outside contact pressure of the rotating platform prosthesis was lower than that of fixed platform prosthesis. Inside and outside contact area of the rotating platform prosthesis was higher than that of fixed platform prosthesis.