Objective: To investigate constitutional and phys ical stamina status in soldiers with different adaption periods in Tibetan areas . Methods: Two hundred and eithty-two male soldiers from a barr acks at an elevation of 3 600 m were divided into 2 groups: the veteran group ( n=143) in Tibet for 1.45±0.22 year, and the recruit group (n=139) in Ti bet for 0.33±0.00 years. The test items included body weight, cirumference, st a nding long jump, chin-up, 100 m dash and 3 000 m jogging, all were evaluated ac cording to the national military standard, which were Comprehensive Evaluation o f Health in Troops, and Examination and Evaluation of the Physical Stamina of So ldiers. Results: The physical stamina indexes of both the vetera ns and the recruits were up to the national military norm on the whole, ranking as moderate. The veteran group showed no significant difference in standing long jump and 100 m dash,（P<0.05), but obvious lower level in chin-up and 3 00 0 m jogging（P<0.01）, compared with the national military norm. The recr ui t group showed significant lower level in chin-up, 100 m dash, 3 000 m jogging as compared with the national military norm（P<0.01）, and also significant lower level in chin-up and 3 000 m jogging （P<0.05 or P<0.01) as compa red with the veteran group. Conclusion: The physical stamina of both the veterans and the recruits meet the basic national military requirements , ranking as moderate. The soldiers who have been in service for over 1 year hav e better explosive force, but they need more tolerance and aerobic exercises. Th e newly recruited need more exercise to raise tolerance to the hypoxic environme nt in plateau areas so as to shorten the adaption time to high altitude.

Objective To investigate the prevalence and influencing factors of dysmenorrhea among female college students in Changchun city, so as to provide scientific basis for health promotion and effective preventive measurement. Methods Non-randomized convenience sampling and face to face interview were used to collect information from female college students aged between 17 and 25 years in 14 universities in Changchun. Chi-square test and logistic regression model were used to analyze influencing factors of dysmenorrhea. Results The average age of 1 071 subjects was 21.21 ± 1.83 years. The prevalence of dysmenorrhea was 86.55%. The proportion of mild dysmenorrhea among the subjects was 62.56%, followed by 33.01% with moderate dysmenorrhea and 4.43% with severe dysmenorrhea; 80.76% of subjects paid attention to keep warm in the daily life. Normal BMI, sleeping before 23 o'clock or between 23 to 24 o'clock, taking exercise frequently or everyday might be the protective factors of dysmenorrhea, and the OR values (95% CI) were respectively as 0.60 (0.37-0.97), 0.56 (0.37-0.84), 0.42 (0.22-0.78) and 0.63(0.42-0.97). Tension and the family history of dysmenorrhea might be the risk factors, and the OR values (95%CI) were respectively 1.63 (1.10-2.41), 4.84 (2.80-8.35). Conclusion The prevalence of dysmenorrhea is high among female college students. Lacking exercise, BMI less than 18.5 kg/m2, staying up late, tension and the family history of dysmenorrhea may be the influencing factors of dysmenorrhea among female college students.

Objective To observe the value of 5.0T MRI for quantifying proton density fat fraction(PDFF)of liver.Methods Liver chemical shift encoded(CSE)MR scanning were prospectively performed using 5.0T,3.0T and 1.5T scanner in 30 volunteers,respectively,and CSE-PDFF were measured.Then MR spectroscopy(MRS)were performed using 5.0T and 1.5T scanner,respectively,and MRS-PDFF were also measured.The consistency of liver PDFF measured on different images was observed,and the value of 5.0T MRI for liver PDFF was analyzed.Results The overall consistencies of liver CSE-PDFF measured with 5.0T,3.0T and 1.5T MR scanner were all good(all ICC＞0.75,all P＜0.001).The consistency of liver CSE-PDFF based on 5.0T and 3.0T,1.5T MR scanner were both good(ICC=0.989,0.992,both P＜0.001).The overall consistencies of CSE-PDFF based on 5.0T MR and MRS-PDFF based on 5.0T and 1.5T MR were both good(both ICC＞0.75,both P＜0.001).CSE-PDFF had good consistency with MRS-PDFF based on same 5.0T MR scanner(ICC=0.988,P＜0.001),and CSE-PDFF based on 5.0T had good consistency with MRS-PDFF based on 1.5T MR scanner(ICC=0.978,P＜0.001).Conclusion 5.0T MRI had high value for quantifying liver PDFF.