Computational investigation of Artemisia pollen deposition in realistic nasal cavities of residents in northwest China / 中华耳鼻咽喉头颈外科杂志

Objective@#To investigate the deposition rate of Artemisia pollen in different nasal cavity regions and its influence factors in residents of northwest China.@*Methods@#Thirty healthy adults from northwest China were enrolled. The computational fluid dynamics (CFD) and discrete phase model (DPM) were used for numerical simulation of nasal structures. The pollen deposition fraction in each anatomical part was counted and the effects of pollen density and breathing rate on deposition were analyzed. SPSS 19.0 software was used for statistical analysis.@*Results@#The hottest deposition parts of Artemisia pollen were nasal septum (30.70%±12.27%), vestibule (27.45%±8.21%), middle turbinate area (13.59%±8.98%) and nasopharynx (7.14%±5.90%). When the inspiratory flow rate increased to 30 L/min, the deposition rates of pollen in nasal vestibule and nasal septum were significantly higher than that at the rate of 15 L/min (43.20%±11.14% vs 27.45%±8.21%, 51.48%±9.77% vs 30.70%±12.27%, t value was -8.126,-5.264, respectively, all P<0.05), which indicated that with the increase of the inspiratory flow rate, the deposition hotspot moved forward. Compared with the wet Artemisia pollen, the deposition rate of the dry pollen in nasal vestibule and nasal septum decreased significantly (16.55%±4.33% vs 27.45%±8.21%, 7.09%±3.69% vs 30.70%±12.27%, t value was 8.669, 9.173, respectively, all P<0.05). The escape rate at outlet increased from 17.00%±9.57% to 43.48%±13.43% (t=-9.282, P<0.05).@*Conclusions@#The deposition of Artemisia pollen in nasal cavity is highly concentrated. The inhalation velocity and the dry-wet degree of pollen are the main determinants of the deposition site.

Experimental study on aerosol particle deposition in human upper respiratory tract model / 医用生物力学

Objective To examine the aerosol particle deposition in human upper respiratory tract model and explore the pathogenesis of toxic aerosol in human upper respiratory tract. MethodsA human upper respiratory tract model was constructed using ABS (Acrylonitrile Butadiene Styrene) plastic, and an experimental system was established to measure the deposition efficiency of aerosol particles with different diameters (0.3 or 6.5 μm) at different breathing intensity (30 or 60 L/min) in this model. Results The deposition patterns of aerosol particles with different diameters and at different breathing intensity in human upper respiratory tract model were similar. The deposition efficiency was generally higher in pharynx，larynx and trachea while being the highest in the area of larynx. Conclusions The breathing intensity has a major impact on aerosol deposition efficiency in the model. Larger aerosol particles are more easily to deposit in the model. Inertial impaction and turbulence intensity are the main mechanisms of aerosol particle deposition.

Research progress in fluid dynamics of human upper respiratory tract / 国际生物医学工程杂志

With the development of technology and the deterioration of environment,more and more attention was attracted to the research on fluid dynamics in human upper respiratory tract.In this paper,the methods of research on fluid dynamics in human upper respiratory tract were introduced,and the mechanical models of human upper respiratory tract which were constructed by the scholars in the resent years were summarized.In addition,the current status of research on the airflow movements,the transportation and deposition of the particles in human upper respiratory tract was analyzed.The developing trend of this field was prospected as well.