ABSTRACT
Objective To study the general mechanical behavior pattern of sensing angular velocity by 3 pairs of human semicircular canals.Methods Sinusoidal head rotation of a healthy subject was simulated by finite element method to analyze the dynamic responses in the above 3 pairs of canals in the left and right inner ear.Results Compared with the complicated node displacement distribution,the volumetric strain distribution of cupula was regular.Specifically,each pair of cupulae expanded or contracted within the same amplitude with the same response frequency to the angular velocity.The ratio of absolute volumetric strain among the horizontal semicircular canal cupula (HC cupula),the anterior semicircular canal cupula (AC cupula),and the posterior semicircular canal cupula (PC cupula),was approximately 1.00∶0.80 ∶ 1.72,which kept constant.In addition,the volumetric strain of HC cupula was in phase with that of AC cupula,but showing 14.4° out of phase with the angular velocity,and 180° out of phase with that of PC cupula.Conclusions The volumetric strain of cupula can preferably characterize the directional coding function of semicircular canal,and the amplitude,frequency and phase of the cupular volumetric strain can encode those of the stimulated angular velocity,respectively.These results will lay the foundation for establishing quantitative relationship of vestibulo-ocular reflex,and provide theoretical references for quantitative assessment for vestibular function by nystagmus examination.
ABSTRACT
Objective To study the general mechanical behavior pattern of sensing angular velocity by 3 pairs of human semicircular canals.Methods Sinusoidal head rotation of a healthy subject was simulated by finite element method to analyze the dynamic responses in the above 3 pairs of canals in the left and right inner ear.Results Compared with the complicated node displacement distribution,the volumetric strain distribution of cupula was regular.Specifically,each pair of cupulae expanded or contracted within the same amplitude with the same response frequency to the angular velocity.The ratio of absolute volumetric strain among the horizontal semicircular canal cupula (HC cupula),the anterior semicircular canal cupula (AC cupula),and the posterior semicircular canal cupula (PC cupula),was approximately 1.00∶0.80 ∶ 1.72,which kept constant.In addition,the volumetric strain of HC cupula was in phase with that of AC cupula,but showing 14.4° out of phase with the angular velocity,and 180° out of phase with that of PC cupula.Conclusions The volumetric strain of cupula can preferably characterize the directional coding function of semicircular canal,and the amplitude,frequency and phase of the cupular volumetric strain can encode those of the stimulated angular velocity,respectively.These results will lay the foundation for establishing quantitative relationship of vestibulo-ocular reflex,and provide theoretical references for quantitative assessment for vestibular function by nystagmus examination.
ABSTRACT
Objective To study the general mechanical behavior pattern of sensing angular velocity by 3 pairs of human semicircular canals. Methods Sinusoidal head rotation of a healthy subject was simulated by finite element method to analyze the dynamic responses in the above 3 pairs of canals in the left and right inner ear. Results Compared with the complicated node displacement distribution, the volumetric strain distribution of cupula was regular. Specifically, each pair of cupulae expanded or contracted within the same amplitude with the same response frequency to the angular velocity. The ratio of absolute volumetric strain among the horizontal semicircular canal cupula (HC cupula), the anterior semicircular canal cupula (AC cupula), and the posterior semicircular canal cupula (PC cupula), was approximately 1.00︰0.80︰1.72, which kept constant. In addition, the volumetric strain of HC cupula was in phase with that of AC cupula, but showing 14.4° out of phase with the angular velocity, and 180° out of phase with that of PC cupula. Conclusions The volumetric strain of cupula can preferably characterize the directional coding function of semicircular canal, and the amplitude, frequency and phase of the cupular volumetric strain can encode those of the stimulated angular velocity, respectively. These results will lay the foundation for establishing quantitative relationship of vestibulo-ocular reflex, and provide theoretical references for quantitative assessment for vestibular function by nystagmus examination.
ABSTRACT
Objective To study the regular pattern of inhalational particulate matter deposition in respiratory tract and its influencing factors during breathing by numerical simulation method. Methods Three-dimensional finite element model of normal human respiratory tract was established to simulate the airflow distributions in respiratory tract during inspiration. The particles were released at the entrance of nose or mouth to simulate the deposition process of suspended particles by inhaled airflow in respiratory tract. Different parameters such as particle diameter, particle density and flow rate of air volume were used for comparative analysis to investigate their functions as influencing factors when particle deposition happened in respiratory tract. Results The particles were mainly deposited in nasal threshold, nasal middle airway, nasopharynx, and bronchial inner wall of respiratory tract. The particle deposition rate increased with the parameters of particle diameter, particle density and air volume flow rate increasing. The influence of different parameters on the deposition rate was not the same. Conclusions The particle is mainly deposited at the site with complex geometry or at the position where path direction changes violently. Particle diameter, density and breathing airflow rate will affect the deposition rate in respiratory tract. These research findings will provide numerical references for the clinical assessment on risk of respiratory diseases caused by air pollution.
ABSTRACT
Objective To establish the biomechanical model of the upper airway, trachea and part of bronchus, and study the influences of different breathing modes on flow characteristics and airway resistance. Methods Based on data of CT scans, three-dimensional finite element model of an anatomically accurate upper airway was established, including the nasal cavity, oral cavity, pharynx, larynx, trachea and part of bronchus. According to several typical cases in reality, numerical simulations were performed on airflow characteristics in upper airway with different proportion of oral airflow and nasal airflow. Results When only a small amount of airflow was inhaled from the mouth, the distribution of airflow characteristics and the airway resistance were similar to the case of nasal inhalation. When a large amount of airflow was inhaled or exhaled through the mouth, the distribution of airflow, pressure and shear stress changed significantly in the respiratory tract. The main differences were observed in the nasal cavity and the oral cavity. Conclusions Establishing the biomechanical model of the upper airway, trachea and part of bronchus is helpful to understand airflow distributions in the entire upper airway and part of bronchus during respiration and to build the platform of numerical research on pathogenesis of upper airway structure-related diseases.
ABSTRACT
<p><b>OBJECTIVE</b>To explore the effect of septoplasty or in combination with out fracture of the inferior turbinate in patients with nasal septum deviation on the airflow field and the nasal airway structure.</p><p><b>METHODS</b>Six patients with nasal septum deviation underwent spiral CT imaging scans before surgery and during the follow-up. The 3D finite element meshes of the nasal airway were developed from the above CT scans. Given three preconditions, the nasal airflow fields were described by the Navier-Stokes and continuity equations at the inspiratory flow rate of 12 L/min. The whole airflow patterns were obtained and then compared with the airflow filed and airway structure changes before and after surgery. SPSS 12.0 software was used to analyze the data.</p><p><b>RESULTS</b>Before surgery, area of the common airway and the middle and ventral medial regions in the concave side were (1.61 ± 0.18), (0.40 ± 0.10), (0.40 ± 0.14) cm(2) respectively, and those of convex side were (1.30 ± 0.18), (0.33 ± 0.05), (0.36 ± 0.10) cm(2) respectively. The differences between both sides were of no statistical significance (Z value was 1.782, 1.363, 0.526 respectively, all P > 0.05). Airflow of the above airways were (361 ± 68), (131 ± 25), (100 ± 28) ml respectively in concave side and (178 ± 33), (59 ± 26), (59 ± 18) ml respectively in convex side, which differences were significant statistically (Z value were 2.207, 2.201, 2.201 respectively, all P < 0.05). The inferior turbinate in concave side [(0.93 ± 0.10) cm] was statistically (Z = 2.214, P < 0.05) bigger than that in convex side [(0.58 ± 0.12) cm] before surgery. The airflow fields were in disorder in both ill-airways. After surgery, area of the common airway was (2.55 ± 0.44) cm(2) in concave side and (2.20 ± 0.72) cm(2) in convex side respectively, and area of the middle and ventral medial regions in the convex side were (0.58 ± 0.13), (0.81 ± 0.26) cm(2) respectively, which differences were of significance statistically when comparing to areas before surgery (Z value were 2.201, 2.201, 2.201, 2.201, P < 0.05). The airflow passed through nasal airway orderly in both sides. But the thickness of inferior turbinate was (0.73 ± 0.08) cm in concave side after surgery, which difference was significant statistically in comparison to that before surgery (Z = 2.264, P < 0.05). Consequently, nasal resistance decreased from (0.41 ± 0.03) kPa×L(-1)×s(-1) to (0.16 ± 0.01) kPa×L(-1)×s(-1) after surgery, the difference was significantly (Z = -2.207, P = 0.027).</p><p><b>CONCLUSION</b>Septoplasty or in combination with out fracture of the inferior turbinate, followed by the self-adaptation consecutively, could improve the airway and breathing capacity of the nose.</p>
Subject(s)
Adult , Female , Humans , Male , Young Adult , Air Movements , Nasal Cavity , Physiology , Nasal Obstruction , General Surgery , Nasal Septum , General Surgery , Respiration , Treatment Outcome , Turbinates , General SurgeryABSTRACT
Objective To study the influence of nasal cavity structure on nasal function of warming and humidifying the inhaled airflow. Method Nine normal persons and two patients with deviation of nasal septum (pre and post operation) were selected as research subjects. The three dimensional finite element model of nasal cavities of these volunteers was established. Numerical simulations for the airflow distribution, the airflow temperature and the airflow humidity in the nasal cavity were performed. Based on the simulation results, comparisons were made between normal nasal cavities and the patient’s nasal cavities as well as between the pre-and post-operative nasal cavities. ResultsIn the wider side of nasal cavity, the volume flow rate and the velocity of airflow were higher and the effect of warming and humidifying on the airflow was worse. For normal people, the nasal cavity for warming and humidifying the inhaled airflow was in the anterior segment of the nose. While for the patients, the main segment of warming and humidifying the inhaled airflow had to depend on the airway geometry. Conclusions The nasal cavity structure can influence the effect of warming and humidifying on the airflow. The parameters describing the geometry of nasal cavity, such as the surface area of nasal airway and volume of nasal cavity, may be a useful measurement for the nasal function of warming and humidifying the inhaled airflow.
ABSTRACT
Objective To study the biomechanical response to cupulae partition of statoreceptor in the rotational chair test and to provide a quantitive platform for vestibular system assessment. Method Based on the histological slides from the right temporal bones from a healthy volunteer, a three dimensional geometry of membranous labyrinth in the vestibular system was reconstructed. The biomechanical response of the volunteer to sinusoidal rotation chair test (0.8 Hz, ±40°) with the head pitch 30° was numerically simulated by the Lagrangian method. ResultsThe maximum displacement of cupula partition in the right horizontal semicircular canal is 54.2 μm, and 15.9 μm in the posterior semicircular canal as well as 43.7 μm in the anterior semicircular canal. However, the displacement response in the anterior semicircular canal is identical on both ears, and it would counteract the eye movement. Secondly, the normal displacement in the right semicircular canal deflect from the side of canal to the side of utricle, while in the left semicircular canal, it deflect from the side of utricle to the side of canal when the chair rotated to the right, and it is opposite when the chair rotate to the left. Conclusions The biomechanical response to cupulae partition by this numerical simulation is in accordance with Flourens law and Ewald laws.
ABSTRACT
Objective To study the method of internal boundary parameters identification of middle ear.Method The numerical model is created using CT technology.Based on Matlab tools,the neural network for identifying internal boundary is proposed.Result The uniform pressure of 105 dB is applied at the outside of the tympanic membrane,and the harmonic analysis is calculated on the model to take the training samples.The internal condition parameters are identified using the good neural network.Conclusions The investiga-tion shows that the inverse method reveals a fast convergence and a high degree of accuracy.
ABSTRACT
Objective To study the method of internal boundary parameters identification of middle ear.Method The numerical model is created using CT technology.Based on Matlab tools,the neural network for identifying internal boundary is proposed.Result The uniform pressure of 105 dB is applied at the outside of the tympanic membrane,and the harmonic analysis is calculated on the model to take the training samples.The internal condition parameters are identified using the good neural network.Conclusions The investiga-tion shows that the inverse method reveals a fast convergence and a high degree of accuracy.
ABSTRACT
<p><b>OBJECTIVE</b>To analyze the different characters of nasal airflow-field between 10 patients with nasal septum deviation and 20 healthy Chinese people by the method of three-dimensional reconstruction of these people's nasal cavity and numerical simulation of the flow field in these nasal cavity models. The character of airflow-field was considered by analyzing the relationship between the structure and function of the human nose.</p><p><b>METHODS</b>Based on the data obtained from the CT images, 10 patients with nasal septum deviation and 20 healthy Chinese people's nasal cavity models were reconstructed by the method of surface rendering. The flow field in these three-dimensional models was simulated with finite element method. The different characters of nasal airflow-field was analysed between two groups of people.</p><p><b>RESULTS</b>The airflow distribution in the nasal cavity model could be acquired from the simulation results of the velocity. The airflow for patients with nasal septum deviation mainly passed through the broad nasal cavity, especially in the middle part of meatus of nose. In the healthy people group, the airflow mainly passed through the main side of the nasal cavity, especially in the middle and inferior part of the meatus of nose. The pressure value at any point in the nasal cavity model could be obtained from the results of the pressure plot. In the patients with nasal septum deviation, the pressure mainly dropped in the part of the nasal septum deviation, accounting approximately 71.36% of the total pressure drop. In the group of healthy people, the pressure dropped mainly in the limen nasi, accounting approximately 58.78% of the total pressure drop. The nasal airway resistance of the patients with nasal septum deviation was larger than that in the group of healthy people.</p><p><b>CONCLUSIONS</b>The three-dimensional nasal airway can reflect the characters of the human nasal airway. It can be used to analyze the change of the aerodynamic in nasal cavity caused by the abnormal anatomy of the nose. This experiment can proof that human nose has the function of self-adaptation, it can build a foundation for the construction of the model of self-adaptation of the human nose.</p>
Subject(s)
Adult , Female , Humans , Male , Young Adult , Adaptation, Physiological , Airway Resistance , Case-Control Studies , Imaging, Three-Dimensional , Models, Anatomic , Nasal Cavity , Nasal Septum , Congenital Abnormalities , Physiology , Nose Diseases , PathologyABSTRACT
<p><b>OBJECTIVE</b>To analyze the allergenicity and immunogenicity of Psilogramma menephron allergen so as to provide the basis for preparing recombinant and standardized allergen vaccines of Psilgramma menephorn.</p><p><b>METHODS</b>The extracts of Psilgramma menephorn were analyzed by SDS-PAGE, and the allergenicity and immunogenicity of the extracts were tested with 9 sera from allergic patients by means of immunoblotting.</p><p><b>RESULTS</b>More than 20 allergen proteins were separated from the extract of Psilgramma menephorn by SDS-PAGE, with the relative molecular weight ranging from 12,000 to 128,000. The relative molecular weight of the allergenic proteins were 74,000 (88.9%), 66,000 (22.2%), 49,000 (22.2%), 36,000 (77.8%), or 25,000 (33.3%), and those of the immunogenic proteins were 79,000 (33.3%), 74,000 (66.7%), 66,000 (22.2%), 49,000 (22.2%), 36,000 (44.4%), or 25,000 (55.6%).</p><p><b>CONCLUSION</b>The relative molecular weight of the major allergenic proteins of Psilgramma menephorn are 74,000 and 36,000, and 74,000 and 25,000 for the major immunogenic proteins. These proteins constitute the major allergenic components for diagnosis and specific treatment of Psilgramma menephorn allergy.</p>
Subject(s)
Adolescent , Adult , Animals , Female , Humans , Male , Middle Aged , Young Adult , Allergens , Allergy and Immunology , Asthma , Blood , Allergy and Immunology , Blotting, Western , Immunoglobulin G , Blood , Lepidoptera , Allergy and ImmunologyABSTRACT
<p><b>OBJECTIVE</b>To identify and isolate the genes encoding the allergens of Psilgramma menephorn by screening the cDNA expression library.</p><p><b>METHODS</b>The cDNA expression library of Psilgramma menephorn was constructed in lambdaZAPIIphage, and the library was screened using the sera from the patients allergic to Psilgramma menephorn and those from the rabbits immunized with Psilgramma menephorn extracts. The positive clones were subcloned into pBluescript plas, and the cDNA in the positive clones were amplified with PCR and sequenced.</p><p><b>RESULTS AND CONCLUSION</b>Five positive clones were obtained by immunological screening of 5 x 10(4) recombinants. Sequence analysis showed that the positive clones contained the new genes of Psilgramma menephorn allergens. This success in isolating these genes may facilitate the development of specific immunotherapy against Psilgramma menephorn allergy and further research of allergic diseases.</p>
Subject(s)
Adult , Animals , Female , Humans , Male , Rabbits , Allergens , Genetics , Allergy and Immunology , Cloning, Molecular , Electrophoresis, Polyacrylamide Gel , Gene Library , Genes, Insect , Immunization , Lepidoptera , Genetics , Sequence Analysis, DNAABSTRACT
@#ObjectiveTo investigate the short-term effect of health education intervention on the recovery of new schizophrenia patients. Methods82 patients were randomly divided into observation group, in which patients accepted routine antipsychotic medication, general nursing and system health education intervention, and control group, in which patients accepted antipsychotic medication and general nursing. Brief psychiatric Rating Scale (BPRS) and Positive And Negative Syndrome Scale (PANSS) were used to assess the effects. ResultsThere was no difference in the score of every factor before intervention (P>0.05), but it became different after intervention (P<0.01 or P<0.05). ConclusionHealth education intervention can improve the effect on schizophrenia.
ABSTRACT
<p><b>OBJECTIVE</b>To study the airflow in nasal cavity by reconstructing 20 volunteers' nasal cavity models and numerical simulation of the flow field in these nasal cavity models.</p><p><b>METHODS</b>Based on the data from the CT images, 20 volunteers' nasal cavity models were reconstructed by the method of surface rendering. The flow field in these three-dimensional models were simulated with finite element method. Some of these volunteers were tested by means of acoustic rhinometry and the test results recorded. Comparisons were performed for the curves from acoustic rhinometry and the results of numerical simulations. The simulation results were explained with the fluid network theory.</p><p><b>RESULTS</b>The airflow distribution in the nasal cavity model could be acquired from the simulation results of the velocity plot. Main airflow would pass through the common nasal meatus in which flux accounted for 50% - 77% of overall flux. The pressure value at any point in the nasal cavity model could be obtained from the results of the pressure plot. The nasal airway resistance in the region of limen nasi accounted for 50% - 65% of overall nasal airway resistance. Comparing the test results with the simulation results the relation could be understood between the change of the cross-section area of nasal cavities and the plot of numerical simulation results of velocity and pressure in airflow field in the nasal cavity models.</p><p><b>CONCLUSIONS</b>Comparing the simulated results of the 20 volunteers' nasal cavity model it can be concluded that the distribution of airflow in nasal cavities is not stationary. The differences among everybody's nasal cavity structure lead to the different airflow distribution in the nasal cavities.</p>