Objective To explore the effects of lead acetate on free radicals and lipid peroxidation in the cerebral cor?tex, cerebellum, and hippocampus in rat brains. Methods SD rats (n=48), who were just weaned, were randomly divided in?to 4 groups base on their weight. Then the rats were fed with lead acetate in drinking water at the final concentrations of 0 mg/L (deionized water), 200 mg/L, 400 mg/L, 800 mg/L respectively. Blood lead level as well as the hydroxyl free radical inhibiting activity, the levels of hydrogen peroxide (H2O2) and malondialdehyde (MDA) in cerebral cortex, cerebellum, and hippocam?pus were measured 60 days after lead contamination in water. Results Upon lead exposure, blood lead levels increased sig?nificantly as compared with the control. The hydroxyl free radical inhibiting activity in cerebral cortex, cerebellum, and hip?pocampus decreased significantly in a dose dependent manner of lead(P < 0.05). And they all correlated negatively with blood lead level (r=-0.505,-0.414,-0.448, P<0.05). By contrast, blood lead level was positively correlated with H2O2 and MDA in these brain tissues (r=0.301, 0.411, 0.378, and 0.404, 0.324, 0.510,P < 0.05). Conclusion Lead exposure can lead to lipid peroxidation of rat brain tissues through inducing free radicals.

OBJECTIVETo investigate the change pattern of primary and secondary school teachers' work ability with the changes in their mental workload.

METHODSA total of 901 primary and secondary school teachers were selected by random cluster sampling, and then their mental workload and work ability were assessed by National Aeronautics and Space Administration-Task Load Index (NASA-TLX) and Work Ability Index (WAI) questionnaires, whose reliability and validity had been tested. The effects of their mental workload on the work ability were analyzed.

RESULTSPrimary and secondary school teachers' work ability reached the highest level at a certain level of mental workload (55.73< mental workload ≤ 64.10). When their mental workload was lower than the level, their work ability had a positive correlation with the mental workload. Their work ability increased or maintained stable with the increasing mental workload. Moreover, the percentage of teachers with good work ability increased, while that of teachers with moderate work ability decreased. But when their mental workload was higher than the level, their work ability had a negative correlation with the mental workload. Their work ability significantly decreased with the increasing mental workload (P < 0.01). Furthermore, the percentage of teachers with good work ability decreased, while that of teachers with moderate work ability increased (P < 0.001).

CONCLUSIONToo high or low mental workload will result in the decline of primary and secondary school teachers' work ability. Moderate mental workload (55.73∼64.10) will benefit the maintaining and stabilization of their work ability.

Faculty ; statistics & numerical data ; Humans ; Occupational Health ; Reproducibility of Results ; Sampling Studies ; Schools ; Stress, Psychological ; psychology ; Surveys and Questionnaires ; Work ; psychology ; Workload ; psychology

Evidence-based medicine (EBM) is an emerging subject which allows us to make health-related policy based on evidence, and is also an important course in medical colleges and universities. Given the current educational objectives and characteristics of evidence-based medicine, this paper proposed an online and offline integrated teaching model of evidence-based medicine based on online platform for medical undergraduates. Online teaching was conducted using online platform which focus on the cultivation of evidence-based thinking and scientific research quality. Offline teaching was in-classroom teaching which focus on basic knowledge and skill learning. Practice of this model not only enriches teaching methods, but also improves the learning effect, thus this model needs to be explored and perfected in the future.

OBJECTIVE: To analyze the effect of bronchoalveolar lavage( BAL) on respiratory function and arterial blood gas of pneumoconiosis patients. METHODS: The published literatures about relationship between BAL and respiratory function and arterial blood gas in pneumoconiosis patients from China National Knowledge Internet,Wanfang Database,Chinese Biomedical Literature Database,Chinese Journal Database,Pub Med,Embase,Web of Science Database and the Cochrane Library Database and so on from 2000 to 2016 were retrieved,collected,and screened by using bibliometric method. The data was analyzed by Meta analysis with the help of Rev Man 5. 0 software. The weighted mean difference( MD) and 95%confidence interval( CI) were calculated on selected literatures. RESULTS: A total of 20 articles were selected and used.The forced vital capacity( FVC)( MD = 0. 21,95% CI: 0. 04-0. 37),the forced expiratory volume in one second( FEV1)( MD = 0. 12,95% CI: 0. 01-0. 23),the maximum ventilatory volume( MD = 10. 73,95% CI: 3. 48-17. 98) and partial pressure of oxygen( MD = 8. 85,95% CI: 0. 30-17. 39) in the patients after BAL were higher than before( P < 0. 05),while the partial pressure of carbon dioxide in artery( MD =-3. 58,95% CI:-5. 61--1. 55) decreased( P < 0. 01).Both of the FEV1/FVC( MD = 2. 08,95% CI:-6. 27-10. 43) and the FEV1%( MD = 0. 86,95% CI:-0. 55-2. 28)had not statistically significance before and after BAL( P > 0. 05). CONCLUSION: BAL can improved respiratory function and arterial blood gas in pneumoconiosis patients.