Objective:To investigate the incidence of hearing loss among helicopter flying personnel, and to analyze the contributing factors.Methods:Basic data of 443 male helicopter flying personnel who received physical examinations at Beidaihe Rehabilitation and Recuperation Center of PLA between March and June 2024 was collected. The hearing threshold levels were measured at 8 frequencies: 250, 500, 1 000, 2 000, 3 000, 4 000, 6 000 and 8 000 Hz. Routine blood tests and blood biochemical tests were performed. Based on the results of pure-tone audiometry, the participants were divided into 2 groups: the hearing loss group (hearing threshold ≤20 dB HL) and the normal hearing group (hearing threshold >20 dB HL). The basic data, routine blood results, and blood biochemical indicators were compared between the 2 groups before the contributors to hearing loss were analyzed.Results:A total of 443 helicopter flying personnel were included in the study, with 82 cases (18.51%) in the hearing loss group and 361 cases (81.49%) in the normal hearing group. There were significant differences in age and pulse between the flying personnel in the 2 groups ( t=2.13, 2.78, P=0.034, 0.006). Among the blood routine indicators, only the mean platelet volume (MPV) was significantly different ( t=2.26, P=0.025). Among the blood biochemical indicators, only homocysteine (HCY) revealed statistically significant difference ( Z=2.30, P=0.021). The determinants of hearing loss in helicopter flying personnel were age ( OR=1.046, 95% CI: 1.060-1.361), pulse ( OR=1.201, 95% CI: 1.060-1.361), MPV ( OR=1.365, 95% CI: 1.016-1.834) and HCY ( OR=1.065, 95% CI: 1.033-1.097). Conclusions:Age, pulse, the MPV and HCY levels can all contribute to hearing loss, and the MPV and HCY can serve as potential biomarkers for hearing loss in helicopter flying personnel. Potential hearing loss should be detected early and personalized interventions should be implemented. Noise exposure should be monitored more rigorously to reduce the risk of occupational hearing loss for helicopter flying personnel and ensure flight safety.

Objective:To investigate the incidence of hearing loss among helicopter flying personnel, and to analyze the contributing factors.Methods:Basic data of 443 male helicopter flying personnel who received physical examinations at Beidaihe Rehabilitation and Recuperation Center of PLA between March and June 2024 was collected. The hearing threshold levels were measured at 8 frequencies: 250, 500, 1 000, 2 000, 3 000, 4 000, 6 000 and 8 000 Hz. Routine blood tests and blood biochemical tests were performed. Based on the results of pure-tone audiometry, the participants were divided into 2 groups: the hearing loss group (hearing threshold ≤20 dB HL) and the normal hearing group (hearing threshold >20 dB HL). The basic data, routine blood results, and blood biochemical indicators were compared between the 2 groups before the contributors to hearing loss were analyzed.Results:A total of 443 helicopter flying personnel were included in the study, with 82 cases (18.51%) in the hearing loss group and 361 cases (81.49%) in the normal hearing group. There were significant differences in age and pulse between the flying personnel in the 2 groups ( t=2.13, 2.78, P=0.034, 0.006). Among the blood routine indicators, only the mean platelet volume (MPV) was significantly different ( t=2.26, P=0.025). Among the blood biochemical indicators, only homocysteine (HCY) revealed statistically significant difference ( Z=2.30, P=0.021). The determinants of hearing loss in helicopter flying personnel were age ( OR=1.046, 95% CI: 1.060-1.361), pulse ( OR=1.201, 95% CI: 1.060-1.361), MPV ( OR=1.365, 95% CI: 1.016-1.834) and HCY ( OR=1.065, 95% CI: 1.033-1.097). Conclusions:Age, pulse, the MPV and HCY levels can all contribute to hearing loss, and the MPV and HCY can serve as potential biomarkers for hearing loss in helicopter flying personnel. Potential hearing loss should be detected early and personalized interventions should be implemented. Noise exposure should be monitored more rigorously to reduce the risk of occupational hearing loss for helicopter flying personnel and ensure flight safety.

Objective To observe the value of MRI combined with serum carbohydrate antigen 125(CA125)and human epididymis protein 4(HE4)for differential diagnosis of type Ⅰ and Ⅱ epithelial ovarian cancers(EOC).Methods Totally 87 EOC patients were retrospectively enrolled.According to pathology,35 cases of type Ⅰ EOC were taken as type Ⅰ group,while 52 cases of type Ⅱ EOC were taken as type Ⅱ group.Conventional MRI manifestations and apparent diffusion coefficient(ADC)value of lesions,as well as CA125 and HE4 were compared between groups,and their efficacy for differential diagnosis of type Ⅰ and Ⅱ EOC were analyzed.Results Significant differences of conventional MRI manifestations of lesions,including composition,mural nodules,peritoneal diffusion and lymph node metastasis,of ADC value of lesions,also of patients'CA125 and HE4 were found between groups(all P＜0.05).The area under the curve(AUC)of conventional MRI manifestations and ADC value of lesions,patients'CA125 and HE4 for distinguishing typeⅠ and type Ⅱ EOC was 0.694,0.730,0.670 and 0.708,respectively,while of the combination of the above four was 0.865,higher than that of each one alone(Z=3.008,2.138,3.005,2.746,all P＜0.05).Conclusion MRI combined with CA125 and HE4 was helpful for differential diagnosis of type Ⅰ and Ⅱ EOC.

Objective: To investigate the mechanical effects during en-mass retraction of maxillary anterior teeth with clear aligner using three-dimensional finite element method. Methods: Cone-beam CT (CBCT) was used to scan a female orthodontic patient (26 years old, from Department of Orthodontics, Stomatological Hospital of Chongqing Medical University) whose maxillary first premolars were extracted and maxillary dentition had been aligned and leveled. A finite element model including maxillary teeth-periodontal ligament (PDL)-alveolar bone-clear aligner was established by using Mimics 17.0, SolidWorks 2016 and Geomagic Studio 2015 software packages. The process of 0.2 mm en-mass retraction of anterior teeth using clear aligner was simulated by using non-linear contact method of Abaqus 6.14. The trend and displacement of maxillary teeth, the stress distribution of PDL and alveolar fossae, and the deformation trend of clear aligner were obtained and analyzed. Results: Under the experimental condition, lingual crown tipping and distal tipping movement of anterior teeth were observed, and all of them had the tendency of overbite increasing.The maximum displacement of the central incisor, lateral incisor and canine were 25.16, 50.34 and 24.98 μm, respectively. Meanwhile, the second premolar, first molar and second molar had the tendency of mesial tipping movement, and the maximum displacement of them were 33.04, 2.90 and 16.63 μm, respectively. The stress distribution both at the PDL and alveolar fossae were consistent with tooth movement pattern. It was noted that the stress in the PDL of the canine and second premolar were comparatively big, and the corresponding apical areas of alveolar fossae appeared stress concentration. Concurrently, it was found that the clear aligner showed stress concentration at the junction of adjacent teeth with a tendency of crown directional dislocation. Conclusions During en-mass retraction of anterior teeth with clear aligner, attention should be paid to the overbite and torque in anterior teeth, and the anchorage protection of posterior teeth. At the same time, we should be careful of root resorption of the teeth on both sides of the extraction space.

Objective To investigate the mechanical effects during en‐mass retraction of maxillary anterior teeth with clear aligner using three‐dimensional finite element method. Methods Cone‐beam CT (CBCT) was used to scan a female orthodontic patient (26 years old, from Department of Orthodontics, Stomatological Hospital of Chongqing Medical University) whose maxillary first premolars were extracted and maxillary dentition had been aligned and leveled. A finite element model including maxillary teeth‐periodontal ligament (PDL)‐alveolar bone‐clear aligner was established by using Mimics 17.0, SolidWorks 2016 and Geomagic Studio 2015 software packages. The process of 0.2 mm en‐mass retraction of anterior teeth using clear aligner was simulated by using non‐linear contact method of Abaqus 6.14. The trend and displacement of maxillary teeth, the stress distribution of PDL and alveolar fossae, and the deformation trend of clear aligner were obtained and analyzed. Results Under the experimental condition, lingual crown tipping and distal tipping movement of anterior teeth were observed, and all of them had the tendency of overbite increasing.The maximum displacement of the central incisor, lateral incisor and canine were 25.16, 50.34 and 24.98 μm, respectively. Meanwhile, the second premolar, first molar and second molar had the tendency of mesial tipping movement, and the maximum displacement of them were 33.04, 2.90 and 16.63 μm, respectively. The stress distribution both at the PDL and alveolar fossae were consistent with tooth movement pattern. It was noted that the stress in the PDL of the canine and second premolar were comparatively big, and the corresponding apical areas of alveolar fossae appeared stress concentration. Concurrently, it was found that the clear aligner showed stress concentration at the junction of adjacent teeth with a tendency of crown directional dislocation. Conclusions During en‐mass retraction of anterior teeth with clear aligner, attention should be paid to the overbite and torque in anterior teeth, and the anchorage protection of posterior teeth. At the same time, we should be careful of root resorption of the teeth on both sides of the extraction space.

Objective To investigate the value of high resolution CT (HRCT) in displaying the anatomic relationship between labyrinth segment of facial canal and cochlea.Methods Totally 110 patients (220 ears) who underwent HRCT were collected.The original images were transferred to workstation for image processing.MPR images were acquired.The anatomic relationship between labyrinth segment of facial canal and cochlea was observed in oblique coronal MPR images.The bony septum between labyrinth segment of facial canal and cochlea was assessed as definite defect (Type Ⅰ),doubtful defect (Type Ⅱ) or complete (Type Ⅲ),respectively.Results There were 71 ears (71/220,32.27％) of Type Ⅰ,diameters of bone fissure ranged from 0.3-1.3 mm (average diameters [0.64±0.26]mm),86 ears (86/220,39.09％) of Type Ⅱ and 63 ears (63/220,28.64％) of Type Ⅲ,with bony septum thickness ranged from 0.3-1.0 mm (average thickness [0.68±0.15]mm).No statistical difference of rates of the above three types was found between different genders,among age groups and between both side of ears (all P＞0.05).Conclusion HRCT is a reliable method to show the anatomic relationship between labyrinth segment of facial canal and cochlea.