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This study aimed to analyze the effects of premolar extraction treatment with vertical control on changes in the anatomy and aerodynamics of the oropharynx in Class II hyperdivergent malocclusion with nonsevere crowding. Thirty-nine patients with Class II hyperdivergent malocclusion were enrolled consecutively. All the participants underwent 4 premolar extractions. The high-pull J-hook and mini-implants were used to provide vertical control. Cone-beam computed tomography was performed before and after treatment. The participants were divided into a decreased lower vertical facial height group (n = 23) and an increased lower vertical facial height group (n = 16) on the basis of superimposition. The aerodynamic characteristics, including airway resistance (inspiration, R in ; expiration, R ex) and maximum velocity (inspiration, Vmax in ; expiration, Vmax ex) at inspiration and expiration, were calculated using computational fluid dynamics. Anatomic characteristics, including volume and cross-sectional area (CSA min), were measured using the Dolphin Imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif). After treatment, the median volume and CSA min increased by 2357 mm3 and 43 mm2, respectively, and median R in and Vmax ex decreased by 0.15 Pa/L/min and 0.24 m×s–1, respectively, in decreased lower vertical facial height group. In contrast, the median CSA min decreased by 9.5 mm2 in the increased lower vertical facial height group. All the changes were statistically significant (all P <0.05). Significant differences in volume, CSA min , R in , and Vmax ex were observed between the 2 groups. Vertical control might improve the anatomic and aerodynamic characteristics of the oropharyngeal airway during premolar extraction treatment of Class II hyperdivergent malocclusion with nonsevere crowding. • Vertical control might improve the anatomy and aerodynamics of the oropharyngeal airway. • Aerodynamic characteristics are simulated through computational fluid dynamics. • Anatomic characteristics are measured through Dolphin Imaging software. • Vertical control is favorable for correcting hyperdivergent Class II malocclusion. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the 2-year postoperative change and influencing factors of the upper airway after mandibular advancement with maxillary setback surgery for patients with a skeletal Class II relationship. Fifty-seven participants who underwent mandibular advancement with maxillary setback surgery were enrolled consecutively. Cone-beam computed tomography was performed preoperatively, 3 months postoperatively (T1), and 2 years (T2) postoperatively. All parameters were measured using Dolphin Imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif). The total volume (V), minimum cross-sectional area (CSA min), and glossopharynx increased significantly in both the short-term (V, 13.33%; CSA min , 33.03%; glossopharynx, 26.73%) and long-term (V, 10.19%; CSA min , 23.18%; glossopharynx, 18.27%) after the surgery. Mandibular advancement, mandibular width increase, preoperative CSA min , and body mass index (BMI) significantly affected 2-year postoperative V increases. Mandibular advancement and BMI significantly affected 2-year postoperative glossopharynx increases. Backward movement of point PNS may lead to a reduction of the nasopharynx; however, downward movement of point PNS, upward movement of point A, and increased maxillary width may compensate for this effect by increasing the likelihood of the nasopharynx opening. Furthermore, mandibular body length at T1 is positively associated with relapse rate ([T2 − T1] / T1) of V and CSA min. Mandibular advancement amount, mandibular width increase, preoperative CSA min , and BMI are the 4 factors for long-term V changes. Patients with a longer mandibular body length might have a lower relapse rate. • Mandibular advancement with maxillary setback surgery is beneficial to the airway. • We evaluated 2-year postoperative changes of the airway after the surgery. • We explored influencing factors of 2-year postoperative airway changes. [ABSTRACT FROM AUTHOR]

Abstract: Thin film alanine-PE dosimeter developed at CIAE is expected to be used as transfer dosimetry system particularly for electron beam dose measurement. Its basic dosimetry characteristics were studied under 60Co γ-ray and electron beam irradiation. The investigated dose range was between 20 and 3×105 Gy. The background dose for the unirradiated dosimeter was about 4Gy. The inter-specimen scattering among 10 replicate irradiated dosimeters was less than 0.6% for the doses of 1kGy after correction of weight differences of dosimeters. The ratio of EPR signals from two batches was about 1.0091±0.0049 for 15 dose points from 70 to 40kGy. No significant dose response dependent on energy or dose rate was found in both γ-ray irradiation (average energy 1.25MeV, dose rate down to 0.4Gy/s) and electron beams irradiation (energy up to 14MeV, dose rate to 108 Gy/s). The irradiation temperature coefficient was about 0.26%/°C between 15 and 50°C in the dose range from 5 to 50kGy. Another important feature, post-irradiation stability, was also studied in detail for dosimeters stored at 4°C, room temperature and 40°C with relative humidity of 98%, 76%, 58%, 33% and 12%. Uncertainty of the dosimetry system for electron beam dose measurement was 2.9% for dose from 102 to 104 Gy, while 5.6% for dose higher than 104 Gy. The preliminary inter-comparison results between CIAE alanine-PE/EPR dosimetry system and the reference dosimetry systems from RISO, JAERI and INCT were comparable within their combined uncertainty, which showed the potential of CIAE alanine-PE/EPR dosimetry system to be used as transfer dosimetry system. [Copyright &y& Elsevier]

This paper presents a theoretical model for predicting the radiative heat transfer rate between high-temperature fluidized bed and immersed walls, which can be used upon the base of emulsion packet model of heat transfer in bubbling fluidized bed. The model adopted radiative flux computation method to calculate radiative heat transfer between fluidized disperse phase contacting to the wall and immersed walls, in which the absorption and back-scattering coefficients was obtained from the reflectivity and the absorptivity of a layer of disperse media of a single particle thickness. In such a model, many factors, such as particle size, particle emissivity, bed void fraction, fluidized bed and wall temperatures, and so on, are included theoretically to calculate radiative heat transfer between immersed walls and fluidized beds. As a result, the model results provide a reasonable explanation of the experimental observation of that radiative heat transfer rate in fluidized beds increases with the increases of the superficial fluidizing velocity. In addition, the modeling prediction for the trend of radiative heat transfer rate between the fluidized bed and its immersed surface on the variation of wall temperature conforms to the classical experimental trend. [Copyright &y& Elsevier]