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Background: In patients with type 2 diabetes mellitus (T2DM), a decrease in muscle function may be related to changes in the biomechanical properties of skeletal muscles. However, the correlations between muscle function and the characteristics of muscle size and stiffness as measured by ultrasound in patients with T2DM are unclear. The aim of this study was to investigate the abilities of conventional ultrasound and shear wave elastography (SWE) to assess muscle properties in patients with T2DM and to correlate the findings with isokinetic muscle testing and functional tests. Methods: Sixty patients from the Department of Endocrinology in The Third Affiliated Hospital of Southern Medical University diagnosed with T2DM were recruited in this cross-sectional study from September 2021 to September 2022. T2DM was defined based on the American Diabetes Association criteria. The exclusion criteria were a history of injury or operation of the lower limb or clinical signs of neuromuscular disorders, any muscle-induced disease, and the presence of other types of diabetes mellitus. Thirty-five matched healthy volunteers were continuously included in the control group. SWE was used to measure the muscle stiffness of the quadriceps femoris [vastus lateralis (VL), rectus femoris (RF), vastus medialis (VM), vastus intermedius (VI)] and the biceps brachii (BB) in a relaxed position, and the shear wave velocity (SWV) values were recorded. Muscle size was measured using conventional ultrasound. The participants underwent isokinetic knee extension/flexion (60°/sec) to assess muscle strength and functional tests of physical performance, including the short physical performance battery, 30-s chair stand test, timed up-and-go test, and 6-meter walk test. All demographics and measured variables were compared using the independent samples t-test. Interclass correlation coefficient analysis was performed on the measurement data obtained by the two operators, and Pearson correlation coefficients were used to determine the relationships between variables. Results: Patients with T2DM exhibited worse physical performance (P<0.05) and weaker lower limb muscle strength (P<0.05) than did healthy controls, but their handgrip strength was comparable (P=0.102). Patients with T2DM had significantly decreased muscle thickness [RF thickness: 10.69±3.21 vs. 13.09±2.41 mm, mean difference =-2.40, 95% confidence interval (CI): -3.56 to -1.24, P<0.001; anterior quadriceps thickness: 23.45±7.11 vs. 27.25±5.25 mm, mean difference =-3.80, 95% CI: -6.33 to -1.26, P=0.004] and RF cross-sectional area (3.04±1.10 vs. 4.11±0.95 cm2, mean difference =-1.07, 95% CI: -1.49 to -0.64; P<0.001) compared to healthy controls. Smaller muscle size was associated with decreased muscle strength (r=0.44-0.69, all P values <0.001). Except for the BB (3.48±0.38 vs. 3.61±0.61 m/s, mean difference =-0.12, 95% CI: -0.35 to 0.11; P=0.257) and VI (2.59±0.34 vs. 2.52±0.23 m/s, mean difference =0.03, 95% CI: -0.06 to 0.18; P=0.299), the muscle stiffness in patients with T2DM was significantly decreased. For the patients with T2DM and healthy participants, the SWV of the RF was 1.66±0.23 and 1.83±0.18 m/s (mean difference =-0.17, 95% CI: -0.25 to -0.08; P<0.001), respectively; that of the VM was 1.34±0.15 and 1.51±0.16 m/s (mean difference =-0.17, 95% CI: -0.24 to -0.10; P<0.001), respectively; and that of VL was 1.38±0.19 and 1.53±0.19 m/s (mean difference =-0.15, 95% CI: -0.23 to -0.07; P<0.001), respectively. Excellent interobserver reliability of the SWV measurements on the muscle of T2DM patients was observed (all intraclass correlation coefficients >0.75; P<0.001). The SWV showed moderate correlations with muscle strength in the RF, VM, and VL (r=0.30-0.61; all P values <0.05). Conclusions: Ultrasound technology exhibits good reliability for repeated measurements of muscle size and stiffness. Reduced muscle stiffness as detected by SWE was demonstrated in patients with diabetes and was associated with decreased muscle strength and impaired functional activity.
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The global COVID-19 pandemic has increased attention to the relationship between the built environment and health, particularly in educational settings where students spend a significant amount of their time. Traditional side daylighting used in schools, while cost-effective and easy to construct, can result in uneven indoor daylighting. To address this issue, this paper proposes a terraced teaching building design model for primary and secondary schools in Guangzhou based on the design experience of an "open-air school movement" during a historical respiratory epidemic in the early 20th century. The proposed design relies on skylight for lighting, and each classroom has an outdoor platform. An optimization algorithm based on Spatial Daylight Autonomy (sDA), Uniformity of Daylighting (UOD), Annual Sunlight Exposure (ASE), Outdoor Platform Area (OPA), Gable Wall Length (GWL), and Space Utilization (SU) is used to obtain the optimal concrete form of the building. To speed up the simulation process, a set of Artificial Neural Network (ANN) based rapid prediction network models for complex forms is proposed. This group prediction method improves the simulation speed by 357 times and grossly speed up the optimization process based on six indexes in the early design stage, resulting in four terraced teaching buildings that meet the above criteria. Overall, the proposed design provides a novel architectural form that ensures overall visual comfort while promoting students' learning and physical health.