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Objective This study was conducted to evaluate the changes of temporomandibular joints (TMJs) through magnetic resonance imaging (MRI) scanning and the electrical changes in mandibular movement and masticatory muscle surface of mild‐to‐moderate obstructive sleep apnoea‐hypopnoea syndrome (OSAHS) patients before and after treatment with mandibular advancement device (MAD). Methods This was a single‐centre, prospective study recruiting OSAHS patients undergoing treatment with MAD in Department of Stomatology, Yannan Hospital, Kunming, China. Patients were recruited from February 2015 to October 2015, and TMJ changes were observed in MRI scanning before and after 18 months of treatment with MAD in cohort 1. The second cohort of the patients were recruited from January 2014 to September 2015 and electrical changes in mandibular movement and masticatory muscle surface of patients before and after 6 months of treatment with MAD. Results In the cohort 1, TMJ changes analysed through MRI scanning, before and after 18‐month treatment with MAD, there was no significant deviation in the angle of joint disc position. A minor change in the position relationship between condylar process, articular disc and articular fossa but not significant was observed. There was no significant difference in the shape and magnitude of mandibular incision edge movement, percussion movement, masticatory movement and condylar central trajectory among the recruited OSAHS patients, before and after 6 months of MAD treatment as analysed through electromyography. Conclusion In this study, from the results it was evident that the effect of MAD on the stomatognathic system of OSAHS patients is minimal.

Three kinds of plant leaves, Chinese white poplar, arborvitae and pine needles were evaluated as a biomonitor for air pollution studies. Thirty-two trace elements have been determined by using relative and the K0 methods of instrumental Neutron Activation Analysis (NAA). The results indicated that Chinese white poplar leaves are a good biomonitor in particular seasons and the pine needles are better than arborvitae for yearly monitoring. Air pollution in Beijing city using poplar as a biomonitor for 46 sampling sites was evaluated. The results indicate some sites are seriously polluted by some elements. In general, northeast in Beijing is a clean area and southwest is relatively polluted.

The prevalence of byssinosis was studied in two cotton mills by a standardized questionnaire and pulmonary function measurements (forced expiratory volume in 1 second; FEV1). In mill A, the dust level was high (57-159 mg/m3). Among 90 participants, 80 were interviewed twice at an interval of 4 months, and disagreement on actual presence or absence of byssinosis was 7.5 percent. Twenty out of ninety workers had complaints of Monday symptoms and the prevalence was 22.2 percent. In mill B, the dust control (6.8 mg/m3) was relatively good. Among 173 participants from the carding room, two had complaints of Monday symptoms and the prevalence was 1.2 percent. A significant correlation was found between duration of employment and prevalence of byssinosis in mill A. FEV1 was measured in 9 byssinotics, 29 nonbyssinotics, and 30 controls before and after work on Mondays and Wednesdays. A significant decrease of 177 ml on average (7.8%) was found in byssinotics after work on Monday, whereas in nonbyssinotics, the decrease of FEV1 was nonsignificant. In controls, a slight increase in FEV1 after work was observed.