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The aerodynamic effects of wing corrugation on insect flight have received widespread attention. However, there has hardly been any specific focus on dynamic changes to corrugation angle in the models. The flexible vein joints containing resilin in the wings of dragonflies and damselflies enable the longitudinal veins to rotate and thereby change the corrugation angles throughout flapping cycles. Therefore, a two-dimensional corrugated airfoil with time-varying corrugation angles is proposed and the aerodynamic performance is evaluated in terms of aerodynamic force, power and efficiency. The results indicate that the airfoil with time-varying corrugations outperforms the rigid one in terms of enhancing thrust and reducing power consumption. The aerodynamic performance of time-varying corrugated airfoils is optimal when the angle varies in a specific range, and an excessively large angle variation may have negative effects. In addition, excessive height or a negative leading edge of the corrugation can lead to a reduction in the thrust. A design concept for the 2D airfoil with time-varying corrugations is provided and the findings are of significance for enhancing the aerodynamic performance of biomimetic flexible flapping-wing vehicles. [ABSTRACT FROM AUTHOR]

Reasonable thermal insulation in cold regions is the key to improve the indoor thermal environment. In this paper, the detached house is taken as the research object, and the sensitivity analysis method is used to quantify the influence of each parameter on the building heat load in three different climate zones. The attenuation characteristics of the heat storage body to the outdoor temperature wave are studied by using the A·M Shklovel calculation method, and the thermal insulation strategy of the envelope structure is optimized by genetic algorithm (GA). The results show that the heat transfer coefficient of roof and exterior wall has the most significant influence on the building heat load. The mean effect response of each factor shows that the Delta (Delta is the value used in Taguchi design methodology to express the relative effect of each factor on the response) of roofs in the three regions is the highest, 3.061, 4.061, and 5.88, respectively. The influence of the type and thickness of the insulation material on the heat storage performance is different. The indoor and outdoor temperature wave penetration attenuation multiple increases with the increase of the thickness of the insulation layer, increases with the decrease of the thermal conductivity of the insulation material, and increases with the increase of the specific heat capacity. The choice of insulation materials is not only related to the above two parameters, but also directly affected by the price. Considering the influence of various factors, the economy of choosing expanded polystyrene board for thermal insulation in the three regions is the best. The optimal thermal insulation thickness of the north wall and roof is 8 and 16 cm (3A climate zone), 10 and 17 cm (2B climate zone), 13 and 20 cm (2A climate zone), respectively. [ABSTRACT FROM AUTHOR]

Traditional Chinese exercise ("TCE" management modalities), including but not limited to Tai Chi, Baduanjin, and Yijinjing, has a good effect on improving the physical function of patients with knee osteoarthritis, but less attention has been paid to the impact on the psychological health of patients, and currently there is insufficient evidence to support it. We conducted this study to provide a systematic synthesis of best evidence regarding the physical and mental health of patients with knee osteoarthritis treated by traditional Chinese exercise. Literature on the effectiveness of traditional Chinese exercise (Tai Chi, Baduanjin, Yijinjing, Qigong, etc.) versus conventional therapy (muscle‐strength training of the lower extremity and aerobic training, wellness education, quadriceps strengthening exercises, etc.) on Western Ontario and McMaster Universities Arthritis Index (WOMAC), visual analog scale (VAS), Short Form‐36 (SF‐36), Timed Up and Go Test (TUG), and Berg Balance Scale (BBS) in knee osteoarthritis (KOA) from Pubmed, Web of Science, Ovid Technologies, China National Knowledge Infrastructure (CNKI), Chinese Science and Technology Periodical Database (VIP), Wanfang Database, and SinoMed were collected from their inception to April 2022. Thirty‐three studies with 2621 cases were included in this study. The study's results indicated that compared with conventional therapy, traditional Chinese exercise had more advantages on patients' WOMAC score, significantly reducing patients' overall WOMAC score (SMD = −0.99; 95% CI: −1.38, −0.60; p < 0.00001) and relieving pain (SMD = −0.76; 95% CI: −1.11, −0.40; p < 0.0001) in patients with KOA. It also has advantages over conventional therapy in improving mental component score (MCS) (SMD = 0.32; 95% CI: −0.00, 0.65; p = 0.05) and physical component score (PCS) (SMD = 0.34; 95% CI: 0.05, 0.62; p = 0.02). Compared with conventional therapy, traditional Chinese exercise can significantly reduce the effect on timed up and go test (TUG) score (SMD = −0.30; 95% CI: −0.50, −0.11; p = 0.002), beck depression inventory (DBI) score (SMD = −0.62; 95% CI: −1.03, −0.22; p = 0.002), and increase the impact on Berg Balance Scale (BBS) score (SMD = 0.60; 95% CI: 0.37, 0.83; p < 0.00001). The findings of this study indicated that traditional Chinese exercise improved body function and mental health in patients with knee osteoarthritis significantly. More high‐quality clinical evidence‐based data was needed to confirm the therapeutic effect of traditional Chinese exercise on the physical and mental health in KOA patients. [ABSTRACT FROM AUTHOR]

Rock-mass unloading often occurs during underground and slope engineering excavations. Here, rock-mass crack initiation and propagation during the excavation unloading progress was simulated using the extended finite element method (XFEM) in ABAQUS. Crack propagation and its influencing factors were studied and discussed after calculating the stress intensity factors at the crack tips, and by recording the crack's shape a dynamic evolution model was produced. The results show that the faster the unloading rate,the longer the crack,and the greater the crack dip angle, the easier the crack initiates. The normal stress on a crack surface decreases while shear stress increases during unloading, and that crack propagation is mainly controlled by shear stress. This is consistent with the theoretical analysis. The final shape of the modeled crack was also close to the result of the physical experiments, indicating the reliability of this study.

Objective: The aim of the present study was to reveal the case characteristics of osteonecrosis of the femoral head (ONFH) in Mainland China. Methods: This cross‐sectional epidemiological study derived data for ONFH patients from July 2016 to December 2018 from the China Osteonecrosis of the Femoral Head Database (CONFHD). The derived data included gender, age, body mass index (BMI), height, occupation, region, and etiology of femoral head necrosis. A descriptive analysis was performed to summarize the epidemiological characteristics of the case data in the CONFHD. Results: A total of 1844 ONFH patients (2945 hips) were included in this study, comprising 1302 men and 542 women. The age of patients ranged from 18 to 95 years, with a median of 50 years, and the male to female ratio was 2.4. Male patients are younger than female patients (48.26 ± 12.56 years old and 55.56 ± 14.94 years old, respectively). Among the 1844 patients (2945 hips), there were 528 (17.92%) hips at ARCO stage I, 941 (31.99%) hips at ARCO stage II, 873 (29.63%) hips at ARCO stage III, and 603 (20.46%) hips at ARCO stage IV. In the subclassification of ARCO stages I and II, the majority of cases were type C; type A comprised the majority in the subclassification of ARCO stage III. According to the Kellgren–Lawrence classification system, among the 603 ARCO stage IV hips, there were 178 (29.52%) grade 1 hips, 201 (33.34%) grade 2 hips, 176 (29.18%) grade 3 hips, and 48 (7.96%) grade 4 hips. Most were from three provinces: Henan (27.3%), Shanxi (13.9%), and Shandong (11.9%). Regarding BMI, 982 patients (53.25%) were overweight or obese. Among all patients, the largest proportion of patients engaged in level IV manual work. Of all the patients, there were 495 (26.84%) with steroid‐induced ONFH, 685 (37.15%) were alcoholics, and 290 (15.73%) had traumatic ONFH. The 495 patients with steroid‐induced ONFH included 278 men (56.16%) and 217 women (43.84 %), had a complete history of hormone use. Among the primary diseases, there were 195 cases (39.39%) of immune system diseases, followed by dermatological diseases, respiratory diseases, nephropathy, and other diseases. There were a total of 685 patients with alcoholic ONFH, 589 of these patients (85.99%) were men. A total of 188 (27.45%) patients had drunk alcohol for 6–10 years (comprising the highest proportion), and 280 patients (40.88%) consumed 3001–3500 mL of alcohol each week (the highest proportion). Conclusion: Osteonecrosis of the femoral head most commonly occurs after the age of 40. Male patients have an earlier onset than female patients, and the number of male patients is approximately twice that of female patients. The BMI of patients was mainly in the overweight and obese range, and half of these patients engaged in level IV manual work. From the imaging findings, the numbers of hips at ARCO stages II and III were greatest, and the number at stage I was relatively small. Among all the causes of disease, alcohol, steroid use and trauma were the three most common reasons for ONFH. [ABSTRACT FROM AUTHOR]

BACKGROUND: Unicompartmental knee osteoarthritis can be treated clinically with either total or partial knee arthroplasty. In the choice of treatment methods, a variety of factors lead to significant differences. There is little reliable evidence to guide the clinical surgical options OBJECTIVE: To compare the short-term curative effect of unicompartmental and total knee arthroplasties in the treatment of unicompartmental osteoarthritis and to explore the effects of two treatment methods on the balance function of patients. METHODS: This was a perspective trial. The patients with unicompartmental knee osteoarthritis were divided into unicompartmental knee arthroplasty group (22 cases, 23 knees) and total knee arthroplasty group (30 cases, 30 knees) based on surgical method. All patients signed the informed consents and the study was approved by the hospital ethical committee. The operation time, hospitalization time, Hospital for Special Surgery score, and the range of motion of the knee joint were compared between two groups to evaluate the early efficacy. The patients' balance function was evaluated using the Tecnobody Proprioception Test System, Timed Up and Go test, and Berg Balance Scale before and 3 months after surgery. RESULTS AND CONCLUSION: (1) Compared with the total knee arthroplasty group, the unicompartmental knee arthroplasty group had shorter operation time and hospitalization time (P < 0.001 ). (2) At 3 months after surgery, there was no significant difference in the Hospital for Special Surgery score, range of motion of the knee joint, Timed Up and Go test or Berg Balance Scale score between two groups (P > 0.05). The Tecnobody Proprioception Test System scores at 3 months after surgery in the unicompartmental knee arthroplasty group were significantly higher than those in the total knee arthroplasty group (P < 0.001 ). (3) These results indicate that both unicompartmental and total knee arthroplasties have satisfactory short-term results in the treatment of unicompartmental knee osteoarthritis. Unicompartmental knee arthroplasty is superior to total knee arthroplasty in terms of operation time, hospitalization time, and balance function recovery. [ABSTRACT FROM AUTHOR]