Three-dimensional printing (3Dp) is being increasingly used in medical education. Although the use of such lifelike models is beneficial, well-powered, randomized studies supporting this statement are scarce. Two spinal fracture simulation models were generated by 3Dp. Altogether, 120 medical students (54.2% females) were randomized into three teaching module groups [two-dimensional computed tomography images (CT), 3D, or 3Dp] and asked to answer 10 key anatomical and 4 evaluative questions. Students in the 3Dp or 3D group performed significantly better than those in the CT group, although males in the 3D group scored higher than females. Students in the 3Dp group were the first to answer all questions, and there were no sex-related differences. Pleasure, assistance, effect, and confidence were more predominant in students in the 3Dp group than in those in the 3D and CT groups. This randomized study revealed that the 3Dp model markedly improved the identification of complex spinal fracture anatomy by medical students and was equally appreciated and comprehended by both sexes. Therefore, the lifelike fracture model made by 3Dp technology should be used as a means of premedical education.

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Summary For maintenance, emergency, or other reasons, pipeline flow can stop. In the development of startup models, the heat diffusion between oil and the surrounding region has not always been considered. Here we establish a numerical restart model for buried pipelines consisting of a new simplified oil heat-transfer model and a cold oil-displacement-flow model considering oil heat diffusion to low-temperature soil and temperature gradients in the axial direction. In addition, we present our studies on the effects of axial-mesh size, timestep, different boundary conditions of the pipe wall, and shutdown in different seasons.