[Establishment and stress analysis of a finite element model of a marathon runner's hip joint based on material properties given by CT gray value]

In this study, a finite element model of the hip joint of a marathon runner was established based on the method of assigning material properties by CT gray value, and the biomechanics of the hip joint were analyzed when standing on one foot. The results of the study demonstrated that the stress was concentrated in the arcuate line, the greater sciatic notch, the pubic comb, and the acetabular region in the pelvis model; in the femoral model, the stress was concentrated in the femoral head, medial side of femoral neck and femoral shaft. The stress is transmitted from the sacroiliac joint to the acetabular dome through the arcuate line, on one side of the femoral head, from the medial side of the femoral neck to the lower side of the lesser trochanter to the medial side of the femoral shaft, and on the other side from the upper side of the femoral neck to the lateral side of the femoral shaft. The maximum principal stress was distributed in the posterior superior of the acetabular roof (7.22 MPa) and the posterior superior of the femoral head (6.68 MPa). The displacement of the model was about 1 to 3 mm at the upper edge of the ilium, and gradually decreased along the femoral axis, and the displacement at the hip joint was about 0.1 to 0.3 mm.

The effect of process parameters and microstructural changes on a new convenience food - quick-frozen paste-coated mushrooms (Agaricus bisporus)

The technology of quick-freezing paste-coated mushrooms (Agaricus bisporus) was studied and optimized. The best microwave pretreatment condition for 1 cm slices, regarding color protection, was 5.4 W/g, for 55, 55-60 and 60 s for mushrooms with 3, 4 and 5 cm diameter caps respectively. For a batch of paste (668.2-1034.6 g), the process parameters considered were oil content (46.6-63.4 g), water content (381-562.6 g) and flour content (166-334 g) with a constant additional content of 30 g starch, 9 g baking powder, 2.6 g carrageenan, 30 g salt and 3 g pepper. These parameters were investigated using response surface methodology (RSM) with a central composite design. The optimal levels of the major paste components were 300 g flour, 432.5 g water and 50 g oil. The freezing time and sensory acceptability for paste-coated Agaricus bisporus(PCAB) under the optimized conditions were 7.49 min and 6.2 respectively. The freezing curves of PCAB were established at different temperatures and the freezing rates were calculated to find the freezing characteristics. In addition, the cell structure of PCAB, frozen at -75 °C, the lowest freezing temperature, and studied using transmission electron microscopy, was similar in quality to that of fresh Agaricus bisporus. The results suggested that Agaricus bisporus can be quick-frozen with a paste coating to produce an acceptable and nutritious convenience food.