ABSTRACT
Infant nutritional status evaluation is a basic experimental skill in the experimental teaching of nutrition and food hygiene. The construction of this virtual simulation experiment can solve the problems of activeness and poor coordination of infants and young children in the actual operation of the experiment. And based on the application of this virtual simulation project, the experimental teaching method of preventive medicine was explored. This experiment adopted online and offline mixed teaching method, which enriches teaching measures and strengthens the standardized process of infant nutritional status evaluation. After 3 semesters of practice from spring 2018 to spring 2020, the proportion of students who achieved excellent grades was 30.09% (34/113), 56.02% (279/498) and 66.79% (1 080/1 617), respectively, which increased significantly year by year ( Ptrend < 0.001). Among all the 2 228 students, 1 983 students (89%) believed that this experimental teaching could better cultivate the ability of autonomous learning. Through the study of virtual simulation experiments, students have improved their subjective initiative, and laid a foundation for the improvement of students' overall quality and the requirements of school elite education.
ABSTRACT
Objective To investigate the occurrence of carotid atherosclerosis in a population of permanent residents (age ≥40 years) at high risk of stroke in Xuejiadao Street,Huangdao District,Qingdao City,and to provide a scientific basis for reduction of carotid atherosclerosis in high-risk communities.Methods Using a cluster sampling method,10 007 permanent residents of age ≥40 years were enrolled in the study.Based on data from an early population screening project,1 478 subjects at high risk of carotid atherosclerosis and stroke were included for analysis.These study subjects were divided into a carotid atherosclerosis risk group and a normal group.General data were recorded,and the results of a physical examination and clinical and biochemical tests were used to analyze risk factors.Results Of 1 478 high-risk subjects aged (58.8± 9.7) years,726 had normal arteries.Of these,264 (36.36％) were males and 462 (63.64％)were females.Carotid atherosclerosis was identified in 752 cases aged (61.4± 9.5) years,with a detection rate of 50.88％.Of these,390 were males (51.86％) and 362 were females (48.14％).Univariate analysis showed that age,male sex,history of heart disease,diabetes,or hypertension,smoking,alcohol intake,waist circumference,and elevated homocysteine and low-density lipoprotein cholesterol levels were positively correlated with carotid atherosclerosis in those at high risk of stroke,while physical exercise showed a negative correlation;these results were statistically significant (P＜0.05).Multiple logistic regression analysis [OR (95％CI)] showed that age [1.621 (1.410-1.865)],male sex [0.474 (0.378-0.594)],history of heart disease [1.336 (1.085-1.645)],diabetes [1.312 (1.021-1.685)],or hypertension [1.408 (1.074-1.846)],and increased low-density lipoprotein cholesterol [1.444 (1.191-1.751)] were positively correlated with carotid atherosclerosis in those at high risk of stroke,while physical exercise [0.810 (0.690-0.950)] showed a negative correlation;these results were statistically significant (P＜0.05).Conclusion Targeting elderly men at high risk of stroke for intervention and guidance to manage hypertension,diabetes,and other chronic diseases,as well as comprehensive preventive and control measures,including reasonable physical exercise,can effectively reduce the occurrence of carotid atherosclerosis in communities.
ABSTRACT
Objective:To construct the Escherichia coli (E. coli)expression system for preparation of the bone morphogenetic protein-2 (BMP2)with collagen-binding domain (CBD),and to study the methods and conditions for expression, purification and renaturation of CBD-BMP2.Methods:CBD sequence was cloned into the N-terminal of BMP2 sequence, the recombinant vector pet21b/CBD-BMP2 was constructed and transformed into E.coli BL21.The expression of recombinant protein was induced using isopropylβ-D-thiogalactopyranoside (IPTG) at 37 ℃.Ni-NTA chelate chromatography was used to purify CBD-BMP-2.Denaturing CBD-BMP2 was refolded by dilution method using ultrapure water.The refolding CBD-BMP2 was filtered through a 0.22μm microfiltration membrane for degermation.The recovery rate was calculated by the ratio of the protein concentration before and after degermation. The expression, purification, and renaturation of recombinant protein were detected by SDS-PAGE method.The concentration of CBD-BMP2 was detected by BCA assay.Results:The recombinant vector pet21b/CBD-BMP2 was successfully transformed into E.coli BL21,and the recombinant protein was expressed as inclusion bodies in E.coli.The SDS-PAGE results showed denaturing protein was dissolved in supernatant of lysis buffer with 8 mol·L-1 urea and the purified recombinant protein existed in elution buffer B with relative molecular mass about 14 000.Two bands (14 000 and 28 000)were seen in the SDS-PAGE picture,which indicated that the monomer was successfully refolded into dimer by dilution method.The concentrations of recombinant protein before and after degermation were 110 and 80 mg · L-1 , respectively, and the recovery rate was about 73%. Conclusion:The recombinant vector pet21b/CBD-BMP2 is transformed into E.coli BL21 successfully,and the recombinant CBD-BMP2 is expressed and refolded efficiently. The methods of prokaryotic expression system for preparing recombinant CBD-BMP2 protein are established.