Objective:To explore whether Corona Virus Disease 2019 (COVID-19) has any impact on human centrifuge training of flying cadets and to provide references to the human centrifuge training for the recovered flying personnel by comparing the changes of flying cadets′ G-tolerance and physiological indicators in human centrifuge training.Methods:Twelve flying cadets who underwent the current batch of human centrifuge training in 2022 were selected and divided into rehabilitation group and control group according to whether they had been infected with COVID-19, with 6 in each group. The rapid G onset rate (ROR) and gradual G onset rate (GOR) were respectively chosen for human centrifuge test. At the same time, the changes of their heart rate and respiratory rate during the tests were recorded, and the G-tolerance situations of the subjects were collected.Results:The average relaxed G-tolerance under GOR (GOR tolerance 1) was (4.2±0.8) G in rehabilitation group, and their average anti-G straining maneuver aided G-tolerance under GOR (GOR tolerance 2) was (5.7±0.6) G. Compared with that of the control group, there was no significant difference in GOR tolerance 1 and GOR tolerance 2 (both P>0.05). There was no significant changes in heart rate and respiratory rate in ROR and GOR human centrifuge tests between 2 groups (all P>0.05). Conclusions:COVID-19 didn't impact the recovered flying cadets' performance in human centrifuge training, as well as the anti-G straining maneuver effect and cardiovascular regulation.

BACKGROUND:Traditional scoliosis orthosis has some disadvantages,such as complex manufacturing process,long processing cycle,poor fit and so on.Three-dimensional printed scoliosis orthosis has the advantages of high manufacturing precision and personalization. OBJECTIVE:To evaluate the efficacy of three-dimensional printed scoliosis orthosis for scoliosis based on multi-criteria decision model. METHODS:Clinical data of 72 patients with scoliosis admitted to Chen Xinghai Hospital of Integrated Traditional Chinese and Western Medicine from January 2019 to October 2022 were retrospectively collected and divided into two groups according to the treatment of orthosis.Study group(n=23)received three-dimensional printed scoliosis orthosis.Traditional group(n=49)received the traditional polypropylene spine brace treatment.The clinical efficacy and complications were compared between the two groups.A multi-criteria decision model for the treatment of scoliosis with three-dimensional printed scoliosis orthosis was established,and the stability of the benefit value,risk value and decision model of the two groups were evaluated. RESULTS AND CONCLUSION:(1)Compared with the traditional group,there were significant differences in the top vertebral offset distance,Cobb angle,top vertebral rotation,Functional Movement Screen score,visual analog scale score and total effective rate in the study group at 6 months after surgery(P<0.05).(2)Among the benefit indexes,Cobb angle had the greatest impact on the condition of patients,while the risk indexes had the greatest impact on dyspnea.(3)The benefit values of the study group and the traditional group for scoliosis were 79 and 64,and the risk values were 74 and 57,respectively.The combined benefit and risk values found that the benefit-risk value of the study group was 16 higher than that of the traditional group.(4)In the range of 0-100%relative risk weight,the benefit-risk value of the study group was always higher than that of the traditional group,which proved that the multi-criteria decision-making model had good stability.(5)It is indicated that three-dimensional printed scoliosis orthosis can better restore the physiological curvature of scoliosis and improve the efficiency of treatment.

Objective:To explore whether Corona Virus Disease 2019 (COVID-19) has any impact on human centrifuge training of flying cadets and to provide references to the human centrifuge training for the recovered flying personnel by comparing the changes of flying cadets′ G-tolerance and physiological indicators in human centrifuge training.Methods:Twelve flying cadets who underwent the current batch of human centrifuge training in 2022 were selected and divided into rehabilitation group and control group according to whether they had been infected with COVID-19, with 6 in each group. The rapid G onset rate (ROR) and gradual G onset rate (GOR) were respectively chosen for human centrifuge test. At the same time, the changes of their heart rate and respiratory rate during the tests were recorded, and the G-tolerance situations of the subjects were collected.Results:The average relaxed G-tolerance under GOR (GOR tolerance 1) was (4.2±0.8) G in rehabilitation group, and their average anti-G straining maneuver aided G-tolerance under GOR (GOR tolerance 2) was (5.7±0.6) G. Compared with that of the control group, there was no significant difference in GOR tolerance 1 and GOR tolerance 2 (both P>0.05). There was no significant changes in heart rate and respiratory rate in ROR and GOR human centrifuge tests between 2 groups (all P>0.05). Conclusions:COVID-19 didn't impact the recovered flying cadets' performance in human centrifuge training, as well as the anti-G straining maneuver effect and cardiovascular regulation.

Objective To study topological structure of a new type of three-dimensional (3D) printed height increasing insoles for leg length discrepancy (LLD) and its effect on biomechanics of lower limbs. Methods Topological structure for middle and rear part of the insole was optimized by solid isotropic microstructures with penalization (SIMP), the force was loaded and the boundary conditions were set according to force area of the insole, and the height increasing insole with thermoplastic polyurethanes (TPU) materials was printed by selected laser sintering (SLS). The insoles were used in 9 patients with LLD, visual analogue scale (VAS) and Maryland foot function scores were used to compare pain and foot function changes of patients before and after using the insole, and the 3D gait analysis system was used to compare spatiotemporal parameters and vertical ground reaction force (vGRF) of both lower limbs. Result sAfter the patient wore 3D printed insole, VAS scores decreased, Maryland foot function scores increased, vGRF of both lower limbs decreased, and the difference of cadence, stance phase and swing phase in both lower limbs decreased. Conclusions The 3D printed height increasing insole after topology optimization can improve coordination of lower limb movement, reduce ground impact, relieve pain and improve foot function, thus providing an effective personalized orthopedic plan for LLD treatment in clinic.

Objective To build an analytic hierarchy process (AHP) of the medical selection for the high performance fighter pilot. Methods According to the consulting results from aeromedical experts ,an AHP model and expert′s judgment matrix were built and checked upon the consistency. Then ,the relative weights of evaluation indexes were calculated.The method was preliminarily applied in the medical selection of high performance fighter pilot. Results An AHP evaluation model of medical selection for high performance fighter pilot was constructed ,including 5 first level indexes of basic physiological function , flight physiological endurance , psychological basis , mental ability , physical fitness and ergonomics ,and 23 second level indexes.The relative weights of 5 first level indexes were 0.172 8 ,0.224 1 ,0.178 5 ,0.289 1 and 0.135 5 corresponding to basic physiological function ,flight physiological endurance , psychological basis , mental ability , physical fitness and ergonomics.The model was applied to comprehensively evaluate the physiological and psychological indexes of 16 hight performance fighter pilot candidates.The scores in turn from high to low were 7.79 ,7.45 ,7.24 ,7.17 ,7.15 ,6.92 ,6.81 ,6.59 ,6.24 ,6.02 ,5.96 ,5.85 ,5.83 ,5.71 ,5.26 and 5.20. Conclusions The AHP provides new method and reference to high performance fighter pilot selection and the application accumulates data and experience for other objective evaluation researches.

Objective To provide objective basis to the authorities for making health policies and aeromedical support measures by investigating the disease spectrum and its variations of the Air Force flying personnel who are grounded by medical reasons. Methods The data of the medical grounding flying personnel of Air Force ,that were collected by the cluster sampling from January 1st , 1987 to December 31st ,2002 ,were retrospectively investigated.The database entry was completed by EpiData 3.0 and the double entry verification was used to ensure the quality.Data collation and statistical analysis were conducted by Excel 2003 and SPSS 11.5. Results ①From 1987 to 2002 ,the youngest age of medical grounding flying personnel of Air Force was 22 years old ,the oldest age was 52 years old ,and the average age was 33.42 years old.The number of the grounding personnel younger than or equal to 35 years old accounted for 62.98%,while the personnel older than 40 years old for 13.89%.②The most common disease that caused the grounding from 1987 to 2002 was neuropsychiatric disease ,that was 164.61 times of the blood system disease which ranked 12th in spectrum.③The top ten diseases in the spectrum of the single disease that caused the grounding from 1987 to 2002 were headache ,syncope ,neurasthenia ,gastric ulcer ,viral hepatitis B ,hypertension , chronic gastroenteritis ,deaf ,ear barometric dysfunction and refractive errors.The composition ratio of top 10 diseases accounted for 58.24%.The top three were functional diseases. Conclusions The medical grounding flying personnel of Air Force show a trend to younger age.Functional diseases account for high proportion.Both flying personnel and aeromedical support personnel should pay attention to these.Taking preventive measures and strengthening the medical interventions are suggested.

Objective To build an analytic hierarchy process (AHP) of the medical selection for the high performance fighter pilot. Methods According to the consulting results from aeromedical experts ,an AHP model and expert′s judgment matrix were built and checked upon the consistency. Then ,the relative weights of evaluation indexes were calculated.The method was preliminarily applied in the medical selection of high performance fighter pilot. Results An AHP evaluation model of medical selection for high performance fighter pilot was constructed ,including 5 first level indexes of basic physiological function , flight physiological endurance , psychological basis , mental ability , physical fitness and ergonomics ,and 23 second level indexes.The relative weights of 5 first level indexes were 0.172 8 ,0.224 1 ,0.178 5 ,0.289 1 and 0.135 5 corresponding to basic physiological function ,flight physiological endurance , psychological basis , mental ability , physical fitness and ergonomics.The model was applied to comprehensively evaluate the physiological and psychological indexes of 16 hight performance fighter pilot candidates.The scores in turn from high to low were 7.79 ,7.45 ,7.24 ,7.17 ,7.15 ,6.92 ,6.81 ,6.59 ,6.24 ,6.02 ,5.96 ,5.85 ,5.83 ,5.71 ,5.26 and 5.20. Conclusions The AHP provides new method and reference to high performance fighter pilot selection and the application accumulates data and experience for other objective evaluation researches.

Objective To provide objective basis to the authorities for making health policies and aeromedical support measures by investigating the disease spectrum and its variations of the Air Force flying personnel who are grounded by medical reasons. Methods The data of the medical grounding flying personnel of Air Force ,that were collected by the cluster sampling from January 1st , 1987 to December 31st ,2002 ,were retrospectively investigated.The database entry was completed by EpiData 3.0 and the double entry verification was used to ensure the quality.Data collation and statistical analysis were conducted by Excel 2003 and SPSS 11.5. Results ①From 1987 to 2002 ,the youngest age of medical grounding flying personnel of Air Force was 22 years old ,the oldest age was 52 years old ,and the average age was 33.42 years old.The number of the grounding personnel younger than or equal to 35 years old accounted for 62.98%,while the personnel older than 40 years old for 13.89%.②The most common disease that caused the grounding from 1987 to 2002 was neuropsychiatric disease ,that was 164.61 times of the blood system disease which ranked 12th in spectrum.③The top ten diseases in the spectrum of the single disease that caused the grounding from 1987 to 2002 were headache ,syncope ,neurasthenia ,gastric ulcer ,viral hepatitis B ,hypertension , chronic gastroenteritis ,deaf ,ear barometric dysfunction and refractive errors.The composition ratio of top 10 diseases accounted for 58.24%.The top three were functional diseases. Conclusions The medical grounding flying personnel of Air Force show a trend to younger age.Functional diseases account for high proportion.Both flying personnel and aeromedical support personnel should pay attention to these.Taking preventive measures and strengthening the medical interventions are suggested.

Objective To compare the clinical effect of non-operative and operative treatment for flail chest.Methods A retrospective case control study was made on 60 cases of flail chest treated from March 2013 to April 2016.There were 42 males and 18 females,at the age range of 36-62 years [(49.8 ± 10.3)years].According to the treatment methods,the patients were divided into non-operation group (28 cases) and operation group (32 cases).Chest CT,pulmonary function and 36-item short-form health survey(SF-36) were measured in all patients 3 months and 6 months after injury.Differences in atelectasis,chest wall deformity,delayed fracture healing,pulmonary function and life quality were analyzed between the two groups.Results Compared to non-operative group at postoperative 3 months,rates of atelectasis,chest wall deformity and delayed fracture healing in operation group were obviously lower,while indices of pulmonary function pulmonary function including forced vital capacity (FVC),forced expiratory volume in one second(FEV1),one second rate (FEV1/FVC) and maximal voluntary ventilation measured value (MVV) in operation group wcre higher,and SF-36 parameters including physical functioning (PF),role-physical (RP),bodily pain (BP),general health (GH),vitality (VT),social functioning (SF) and mental health (MH) in operation group were better (all P ＜ 0.05).As to the data measured 6 months after injury,there were no significant differences between the two groups,except that the rate of chest wall deformity in non-operative group (6 cases,39％) was higher than that in operation group (11 cases,19％) (P ＜ 0.05).As to c hest CT,indices of pulmonary function and SF-36 parameters (P ＜ 0.05),there were no significant differences within operation group at postoperative 3 months and 6 months (P ＞ 0.05).Non-operation group showed better results in rate of atelectasis,rate of delayed fracture healing,indices of pulmonary function and SF-36 parameters measured 6 months after injury than the detections at postoperative 3 months (P ＜ 0.05),without difference in rate of chest wall deformity (P ＞ 0.05).Conclusions Surgical treatment of flail chest can accelerate fracture healing,reduce rate of chest wall deformity and improve life quality of patients early compared to non-operative treatment.Although there is no obvious difference in life quality of patients between operative and non-operative treatment 6 months after injury,but the chest wall deformity remains significantly different.

AIM:To explore the mechanism by which over-expression of enhancer of zeste homolog 2 (EZH2) in a panel of gastric cancer cell lines is involved in tumorigenesis of gastric cancer .METHODS: Real-time PCR and Western blot were employed to examine the mRNA and protein levels of EZH 2, respectively.MTS assay, cell migration and soft agar assay were performed to investigate the role of EZH 2 in the regulation of stomach cancer behaviors .The effect of EZH2 on NF-κB target gene expression was determined by Luciferase reporter and real-time PCR.Co-immunoprecipitati-on was used to analyze the interaction of EZH 2 and p65 in HEK293T cells.RESULTS: The expression levels of EZH2 were significantly increased in the gastric cancer cells compared with normal gastric epithelial cells .Pharmacological inhibi-tion by DZNep or knockdown of EZH2 significantly compromised AGS and SNU-16 cell activity , cell migration and anchor-age-independent cell growth.Moreover, siRNA knockdown of EZH2 impaired NF-κB downstream targets, such as IL-8, CXCL5 and CCL20.In addition, the interaction of EZH2 and p65 was detected.CONCLUSION: EZH2 mediates the growth of gastric cancer cells through the regulation of NF-κB downstream gene expression .