Objective:To study the correlation between myopia growth and physical development of primary school student in Shihezi area of Xinjiang Uyghur Autonomous Region by measuring the ocular biometry and physical parameters of the eye, and to provide an objective basis for the development of myopia prevention and control.Methods:A cross-sectional study design was used. The Grade 1-6 students from 33 schools in Shihezi area were randomly selected in October 2023. The children were classified according to age into the low age group (6-9 years) and the high age group (10-13 years).The children′s height, weight, axial length (AL), maximum keratometry (steepest keratometry, K1), and minimum keratometry (flattest keratometry, K1) were measured. The body mass index (BMI), keratometric astigmatism (ΔK), mean keratometry (K), corneal radius (CR) and AL/CR were calculated. Correlation analyses were performed between ocular biometry and physical parameters. LASSO regression analysis was used to screen the best variables, and linear regression models were constructed after adjusting for confounding factors of age and sex.Results:A total of 3 986 children aged 6-13 years were included in this study, including 2 094 boys (52.53%) and 1 892 girls (47.47%); 2 162 in the lower age group and 1 824 in the upper age group. Girls had higher K, ΔK and AL/CR values than boys (43.38 D vs 42.7 D, t=-7.84, P<0.01; 1.1 D vs 1.01 D, t=-2.14, P=0.03; 2.97 vs 2.96, t=3.32, P=0.02). Boys had higher AL, height, weight and BMI than girls (23.47 mm vs 23.02 mm, t=13.77, P<0.01; 1.34 m vs 1.33 m, t=3.02, P=0.03; 32 kg vs 29.5 kg, t=7.82, P<0.01; 17.4 vs 16.52, t=10.36, P<0.01). LASSO regression was used to screen the 3 physical parameter variables (height, weight, and BMI) to determine that height was the best physical parameter variable for AL/CR. After adjusting for confounders, it was shown that in the low age group (6-9 years), there was a significant positive correlation between children′s height and AL/CR ( b=0.174, 95% CI: 0.106 to 0.241, P<0.001), whereas in the high age group (10-13 years), there was no correlation between children′s height and AL/CR ( b=0.086, 95% CI:-0.038 to 0.21, P=0.174). Conclusion:There was a positive correlation between height and myopia growth in the lower age group of children in Shihezi area, Xinjiang Uyghur Autonomous Region; there was no correlation between height and myopia growth in the higher age group.

Objective:To study the correlation between myopia growth and physical development of primary school student in Shihezi area of Xinjiang Uyghur Autonomous Region by measuring the ocular biometry and physical parameters of the eye, and to provide an objective basis for the development of myopia prevention and control.Methods:A cross-sectional study design was used. The Grade 1-6 students from 33 schools in Shihezi area were randomly selected in October 2023. The children were classified according to age into the low age group (6-9 years) and the high age group (10-13 years).The children′s height, weight, axial length (AL), maximum keratometry (steepest keratometry, K1), and minimum keratometry (flattest keratometry, K1) were measured. The body mass index (BMI), keratometric astigmatism (ΔK), mean keratometry (K), corneal radius (CR) and AL/CR were calculated. Correlation analyses were performed between ocular biometry and physical parameters. LASSO regression analysis was used to screen the best variables, and linear regression models were constructed after adjusting for confounding factors of age and sex.Results:A total of 3 986 children aged 6-13 years were included in this study, including 2 094 boys (52.53%) and 1 892 girls (47.47%); 2 162 in the lower age group and 1 824 in the upper age group. Girls had higher K, ΔK and AL/CR values than boys (43.38 D vs 42.7 D, t=-7.84, P<0.01; 1.1 D vs 1.01 D, t=-2.14, P=0.03; 2.97 vs 2.96, t=3.32, P=0.02). Boys had higher AL, height, weight and BMI than girls (23.47 mm vs 23.02 mm, t=13.77, P<0.01; 1.34 m vs 1.33 m, t=3.02, P=0.03; 32 kg vs 29.5 kg, t=7.82, P<0.01; 17.4 vs 16.52, t=10.36, P<0.01). LASSO regression was used to screen the 3 physical parameter variables (height, weight, and BMI) to determine that height was the best physical parameter variable for AL/CR. After adjusting for confounders, it was shown that in the low age group (6-9 years), there was a significant positive correlation between children′s height and AL/CR ( b=0.174, 95% CI: 0.106 to 0.241, P<0.001), whereas in the high age group (10-13 years), there was no correlation between children′s height and AL/CR ( b=0.086, 95% CI:-0.038 to 0.21, P=0.174). Conclusion:There was a positive correlation between height and myopia growth in the lower age group of children in Shihezi area, Xinjiang Uyghur Autonomous Region; there was no correlation between height and myopia growth in the higher age group.

10 male subjects participated in the environmental simulation study to evaluate the operation ergonomics at high-temperature in the cockpit. Grip strength, perception, dexterity, reaction and intelligence were measured respectively during the tests at 40 degrees C and 45 degrees C, simulating the high-temperatures in a simulation cockpit chamber. Then the data obtained were compared to the combined index of heat stress (CIHS). The average values of each item of the subjects' performance at the two different temperatures are compared. The results indicated that CIHS exceeded the heat stress safety line after 45 min at 40 degrees C, grip strength decreased by 12%, and perception increased by 2.89 times. In contrast, at 45 degrees C, CIHS exceeded the safety line after 20 min, grip strength decreased by 3.2%, and perception increased by 4.36 times. However, Finger dexterity was less affected. Reaction ability was first accelerated, and then slowed down. The error rate in the intelligence test increased to a greater extent. At the high temperatures, the minimum perception was the most affected, followed by grip strength, reaction and finger dexterity were less affected, while the intelligence did not decline, but rise.
Adult ; Aerospace Medicine ; Aircraft ; Computer Simulation ; Ergonomics ; Heat Stress Disorders ; physiopathology ; Hot Temperature ; adverse effects ; Humans ; Male ; Young Adult

Objective To provide the oxygen supply apparatus when the civil aviator and airforce pilot are inspected the hypoxia tolerance and altitude tolerance in the hypobaric environment.Methods Demand oxygen and contstant flow oxygen were supplied.Results The portable hypobaric oxygen supply apparatus can supply mixed oxygen below the altitude 8 000 m,and the oxygenous concentration of mixed oxygen was adjusted according to the altitude.The pure oxygen was supplied when the altitude was at 8 000～12 000 m.Conclusion The normal and emergency oxygen supply performance can fulfill the system physiological requirements.The portable hypobaric oxygen supply apparatus may be used by the persons engaging in special task on plateau also.

Objective In order to provide important theoretical basis for further improving design of DC-7/7A high altitude partial pressure suit and FTF-2 air ventilation suit (named as A suit and B suit), the performance of ventilating heat dissipation of DC-7/7A and FTF-2 was studied. Methods Five healthy volunteers were enrolled to took participate in A group and B group tests. Environmental weather conditions for A and B suits were set at Tdb 40℃ and 45℃,rh 45% and 40% respectively, and the test time was 90min and 120 min respectively. Results During the test for A group and B group, Ts ranged from 31.5℃ to 34.5℃ for human comfort. Average skin temperatures of the lower part of the body were from 33.1℃ to 33.8℃. Skin temperatures of the legs did not obviously change or slightly lowered. Heart rate showed an increase of 12 beats/min and 14 beats/min. Sweat quantities were measured to be 0.288?0.056kg/1.5h and 0.445kg?0.077 kg/2h respectively. Evaporation rates were 77.4?3.6% and 84.2?2.4% respectively. Subjective uncomfortable sensation was more obvious as test time went on. Conclusion The results of the ventilating heat dissipation for both groups were quite good, but the findings suggested that the number of the ventilating holes for some important sites should shall be re-considered. Pilots wearing A group and B group with ventilation function would still suffer from mild heat stress and obvious subjective discomfort in hot enviroment.

The apparatus introduced in this paper can be used to measure and record the realtime environmental parameters and such physical information of individual protection equipment as the temperature,thermal current and thermal insulating value.The apparatus has several advantages including high accuracy,practicability,reliability and easy to operate.