[ABSTRACT]OBJECTIVETo explore the basic characters of the airflow-field in Chinese people's nasal cavity by computational fluid dynamics.METHODSThe three-dimensional, finite-element mesh were developed from Spiral CT imaging scans of nose of the 40 healthy Chinese people. Given the following spatial boundaries of the flow field: no-slip condition was imposed at the surface of the nasal airway walls; a standard atmosphere pressure condition was established at the inlet; a velocity vector was specified at the outlet (nasopharynx), which was obtained under the condition of aspiratory flow rate (12 L/min), the full Navier-Stokes and continuity equations were solved to obtain the airflow pattern.RESULTS1. The airflow passed mainly through left or right side of the nasal airway in the whole 40 cases (left 33, right 7),and the volume of air through the main-side is (320±28) ml while non-main-side (180±45) ml. 2. Airflow velocity: airflow of anterior nostrils, internal nostrils, the middle and inferior parts of the total meatus in the main-side were (5.01±2.12) m/s, (7.00±1.75) m/s, (5.08±1.55) m/s, (4.12±1.40) m/s respectively, and those in non-main-side were (2.01±0.94) m/s, (2.40±0.34) m/s, (1.99±1.0) m/s, (2.01±0.65) m/s respectively, which differences between the both sides were of statistical significance (allP<0.05); airflow of middle meatus, inferior meatus and olfactory cleft in the main-side were (2.08±0.43) m/s, (1.60±0.95) m/s, (1.64±0.80)m/s respectively, and those in non-main-side were (1.89±0.52) m/s, (1.49±0.89) m/s, (1.50±0.75) m/s respectively, which differences were significant statistically (allP>0.05); 3. The airflow form appeared to be linear in the middle and inferior parts of the nasal cavity. 4. Velocity in maxillary sinus cavity was almost 0 m/s.CONCLUSIONThe airflow passes mainly through the middle and inferior parts of the meatus with higher velocity in laminar form and airflow of middle meatus, inferior meatus and olfactory cleft are low and the velocity were slow. Besides, airflow in maxillary sinus cavity diffuses free mainly.

[ABSTRACT]OBJECTIVETo study the deposition of suspended particles in the respiratory tract during human breathing.METHODSBased on CT data, three dimensional finite element model of an anatomically accurate respiratory tract, including the nasal cavity, oral cavity, pharynx, larynx, trachea and parts of tracheobronchial tree, is established. Numerical analysis for the deposition of suspended particles in the respiratory tract was conducted. RESULTSThe velocity and pressure distributions of airflow in the respiratory tract were obtained, as well as the particles path and their deposition law.CONCLUSION Respiratory tract plays an important role in filtering suspended particles in the air during breathing. The main deposition sites of the particles were at the front of the inferior turbinate and the posterior pharyngeal wall.

OBJECTIVE: To investigate the nasal airflow-field in relation with the structure and function of the human nose. METHOD: The 3-D finite-element mesh is developed from Spiral- CT imaging scans of the 25 healthy volunteers' noses. Given three preconditions, the nasal air-flow is described by the Navier-Stokes and continuity equations at the inspiratory flow rate of 10 min, then the whole airflow patterns are obtained for further analysis. RESULT: (1) In 5 cases, the airflow passes mainly through the middle medial region in both sides in the nasal airway. In remaining 20 cases, the airflow passes mainly through the middle and ventral medial regions in one side in the nasal cavity while little air passes through middle medial regions in another the other side through which little air passes. (2) The differences of velocity in the nasal valve, middle and ventral medial regions of the nasal airway between mainly side and non maingnot-mainly side are of statistical significance, while those in the olfactory split, middle and inferior meatuses in both sides are of no statistical significance. (3) In the mainly side, the most rapid air speed occurred in the nasal valve , the second rapid velocity in the middle medial region and the third in the ventral medial regions, the slowest velocity in the olfactory split, middle and inferior meatuses. In notion- mainly side, the velocity in all regions is slow without statistical significance. CONCLUSION (1) At the inspiratory flow rate of 10 L/min, the middle and ventral medial regions act as the main airways in nasal cavity. (2) The airflow in nasal cavity can be directed effectively and reasonably by nasal valve, inferior turbinate, middle turbinate in turn, which may be consistent with the nasal cycle functionally.
Adult ; Asian Continental Ancestry Group ; Female ; Humans ; Image Processing, Computer-Assisted ; Imaging, Three-Dimensional ; Male ; Models, Biological ; Nasal Cavity ; diagnostic imaging ; Pulmonary Ventilation ; Tomography, X-Ray Computed

Objective To evaluate the effect of clemastine fumarate on Toll-like receptor 4/phosphatidylinositol-3-kinase/serine-threonine kinase (TLR4/PI3K/Akt) signaling pathway during hypoxia-reoxygenation (H/R) in rat cardiomyocytes.Methods H9C2 cells of rats cultured in vitro were seeded in culture wells or dishes at a density of 1×105 cells/ml and divided into 3 groups (n=11 each) by using a random number table method:control group (group C),H/R group and clemastine fumarate group (CF group).Cardiomyocytes were exposed to 5％ CO2-95％ N2in a low-glucose DMEM medium at 37℃ for 4 h followed by 4 h reoxygenation.At 4 h of reoxygenation,the cell viability was detected by CCK-8 assay,the ultrastructure was observed with a transmission electron microscope,the expression of TLR4,PI3K,phosphorylated Akt (p-Akt) and caspase-3 was detected by Western blot,and the expression of TLR4,PI3K and caspase-3 was detected by immunofluorescence.Results Compared with group C,the cell viability was significantly decreased,the expression of TLR4 and caspase-3 was up-regulated,and the expression of PI3K and p-Akt was down-regulated in group H/R (P＜0.05).Compared with group H/R,the cell viability was significantly increased,the expression of TLR4 and caspase-3 was down-regulated,the expression of PI3K and p-Akt was up-regulated (P＜0.05),and the mitochondrial damage was significantly attenuated in group CF.Conclusion The mechanism by which clemastine fumarate alleviates H/R injury to rat cardiomyocytes may be related to inhibiting TLR4 expression and activating PI3K/Akt signaling pathway.

Ear and upper airway are portal organs of human body. Because of their fine and narrow structure, the non-invasive research and the effect of clinical diagnosis and treatment in traditional medicine are always unsatisfactory. With the development of computer technology, numerical simulation has become an effective means of auxiliary research. Numerical simulation can reproduce or evaluate the diagnosis and treatment of ear and upper airway diseases, and it is a powerful means to promote the development of basic medicine and technology of clinical diagnosis and treatment. The application of numerical simulation in relationship between the structure and function of ear and upper airway, the influence of diseases on function, the evaluation of clinical diagnosis and treatment technology， as well as the design of related medical devices were reviewed. The clinical application of numerical research in ear and upper airway was prospected, so as to provide references for the future clinical diagnosis and treatment of ear and upper airway.