Analysis of dynamic damage on middle ear under high pressure / 医用生物力学

Objective To study the middle ear damage caused by high pressure.Methods The finite element model of human middle ear was established based on CT scanning,and the change of stress,strain and displacement of the tympanic membrane and stapes footplate was analyzed when the model was applied with timevarying pressure.Results The satisfactory agreement between the computational results and the corresponding experimental data in the literature could indicate the validity of the model.High pressure would cause damage to middle ear,and the damage would be aggravated with the pressure increasing.Rapid pressurization could make severely damage to middle ear,but have minor effect on inner ear.Slow pressurization could also lead to middle ear damage,but inner ear might be damaged before the injury to middle ear.Conclusions High pressure can easily lead to the ear damage;therefore,the pressurized rate should be controlled strictly to protect the hearing during pressurization.

Influence of noise under normal and high pressure environment on the cochlea / 医用生物力学

Objective To study the influence of noise under normal and high pressure environment on the cochlea,so as to make up for the defect caused by the lack of testing means to study the noise effect on behavioral characteristics of cochlear hearing by using numerical simulation method.Methods Based on CT scan images of healthy cochlea,and combined with self-programming,the three-dimensional finite element model of the cochlear spiral was established by using PATRAN software.Analysis on flow solid coupling frequency response and transient response was conducted by using NASTRAN software,and the impact of noise under normal and high pressure environment on the cochlea was numerically simulated.Results The calculated results were in agreement with the experimental results reported in the literature,which verified the correctness of the model.When the frequency was lower than 5 kHz,the basement membrane displacement by noise excitation under normal and high pressure environment was basically the same;when the frequency was higher than 5 kHz,the basement displacement by noise excitation under normal environment decreased gradually.Conclusions Under high pressure environment,the high-frequency noise shows a more obvious effect on the basilar membrane.The numerical simulation results can make up for the deficiency in studies about noise effect on characteristics of human cochlear hearing due to the lack of experimental methods,and provide new ideas and theoretical support for targeted experimental study of the cochlea in the future.

Analysis of dynamic damage on middle ear under high pressure / 医用生物力学

Objective To study the middle ear damage caused by high pressure.Methods The finite element model of human middle ear was established based on CT scanning,and the change of stress,strain and displacement of the tympanic membrane and stapes footplate was analyzed when the model was applied with timevarying pressure.Results The satisfactory agreement between the computational results and the corresponding experimental data in the literature could indicate the validity of the model.High pressure would cause damage to middle ear,and the damage would be aggravated with the pressure increasing.Rapid pressurization could make severely damage to middle ear,but have minor effect on inner ear.Slow pressurization could also lead to middle ear damage,but inner ear might be damaged before the injury to middle ear.Conclusions High pressure can easily lead to the ear damage;therefore,the pressurized rate should be controlled strictly to protect the hearing during pressurization.

Influence of noise under normal and high pressure environment on the cochlea / 医用生物力学

Objective To study the influence of noise under normal and high pressure environment on the cochlea,so as to make up for the defect caused by the lack of testing means to study the noise effect on behavioral characteristics of cochlear hearing by using numerical simulation method.Methods Based on CT scan images of healthy cochlea,and combined with self-programming,the three-dimensional finite element model of the cochlear spiral was established by using PATRAN software.Analysis on flow solid coupling frequency response and transient response was conducted by using NASTRAN software,and the impact of noise under normal and high pressure environment on the cochlea was numerically simulated.Results The calculated results were in agreement with the experimental results reported in the literature,which verified the correctness of the model.When the frequency was lower than 5 kHz,the basement membrane displacement by noise excitation under normal and high pressure environment was basically the same;when the frequency was higher than 5 kHz,the basement displacement by noise excitation under normal environment decreased gradually.Conclusions Under high pressure environment,the high-frequency noise shows a more obvious effect on the basilar membrane.The numerical simulation results can make up for the deficiency in studies about noise effect on characteristics of human cochlear hearing due to the lack of experimental methods,and provide new ideas and theoretical support for targeted experimental study of the cochlea in the future.

Dynamic damage analysis of middle ear under high pressure / 医用生物力学

Objective To study the middle ear damage caused by high pressure. Methods The finite element model of human middle ear was established based on CT scanning, and the change of stress, strain and displacement of the tympanic membrane and the stapes footplate was analyzed when the model was applied with time-varying pressure. Results The satisfactory agreement between the computational results and the corresponding experimental data in the literature indicated the validity of the model. High pressure would cause damage to the middle ear, and the damage would increase with the pressure increasing. Rapid pressurization could severely damage the middle ear, but with a small effect on the inner ear. Slow pressurization could also lead to the middle ear damage, but the inner ear might be damaged before the damage to the middle ear. Conclusions High pressure can easily lead to the ear damage; therefore, the pressurized rate should be controlled strictly during pressurization in order to protect the hearing.

Influence of noise under normal and high pressure environment on the cochlea / 医用生物力学

Objective To study the influence of noise under normal and high pressure environment on the cochlea, so as to make up for the defect caused by the lack of testing means to study the noise effect on behavioral characteristics of cochlear hearing by using numerical simulation method. Methods Based on CT scan images of healthy cochlea, and combined with self-programming, the three-dimensional finite element model of the cochlear spiral was established by using PATRAN software. Analysis on flow solid coupling frequency response and transient response was conducted by using NASTRAN software, and the impact of noise under normal and high pressure environment on the cochlea was numerically simulated. Results The calculated results were in agreement with the experimental results reported in the literature, which verified the correctness of the model. When the frequency was lower than 5 kHz, the basement membrane displacement by noise excitation under normal and high pressure environment was basically the same; when the frequency was higher than 5 kHz, the basement displacement by noise excitation under normal environment decreased gradually. Conclusions Under high pressure environment, the high-frequency noise shows a more obvious effect on the basilar membrane. The numerical simulation results can make up for the deficiency in studies about noise effect on characteristics of human cochlear hearing due to the lack of experimental methods, and provide new ideas and theoretical support for targeted experimental study of the cochlea in the future.

Effects of high pressure on the cochlea / 医用生物力学

Objective To study the effects of high pressure environment on human cochlea, so as to supplement inadequate study on cochlea behavior under high pressure conditions due to insufficient experimental methods, and provide new ideas for the targeted research on cochlea in future. Methods Based on CT scan images of normal human cochlea and combined with self-compiling program and the software PATRAN, a three-dimensional finite element model of spiral cochlea was constructed. The fluid-solid coupling frequency response analysis and transient response analysis were made by using NASTRAN. The effect of high pressure on cochlea was then investigated by numerical simulation. Results The simulated results of ratio of displacement at 12 mm from basilar membrane to that at the oval window were consistent with those reported in the literature, which verified the correctness of the model. In high pressure environment, the amplitude of cochlea basilar membrane at characteristic frequency point would decrease with the pressure increasing. Conclusions High pressure conditions can ultimately lead to the loss of human hearing. The research findings provide the theoretical support for developing high pressure buffer devices in clinic.

Effects of bacterial biofilm on hearing restoration with titanium partial ossicular prosthesis replacement / 医用生物力学

Objective To study effects of the bacterial biofilm at different growth stages on dynamic behavior of the titanium partial ossicular replacement prosthesis (PORP), so as to provide theoretical references for clinical treatment of diseases such as secretory otitis media. Methods Based on the CT scan images of normal human right ear and combined with the self compiling program, a 3D finite element model of the ear was reconstructed for dynamic analysis on sound conduction, and compared with the experimental data. The model was computed by harmonic response analysis method, and the sound conduction effect of bacterial biofilm grown on PORP at different growth stages was analyzed. Results The simulated amplitude of umbo and stapes footplate was in accordance with experimental measurements, which confirmed the validity of this numerical model. The existence of biofilm would cause 0-1.6 dB hearing loss at low frequencies. The growth of biofilm in the radial direction of PORP would cause 0-12 dB hearing loss at intermediate and high frequencies, especially at 8 kHz, and the hearing loss could be as high as 11.2 dB. Conclusions The bacterial biofilm has an impact on hearing by reducing the hearing at low frequencies while raising a little at high frequencies. The biofilm grown in the radial direction of PORP will reduce hearing, and affect the working efficiency of PORP on hearing restoration.

Inverse derivative of elastic modulus for human ear based on neural network / 医用生物力学

Objective To obtain elastic modulus through displacement of the ear structure. Methods The finite element model (FEM) of human ear structure based on Patran software was constructed and the neural network for inverse derivative of elastic modulus for the ear was established using Matlab software. The frequency response of the ear structure FEM was calculated to obtain the displacements of tympanic membrane and stapes. The displacements acting as input data of training samples and the corresponding elastic modulus acting as output data were used to train the neural network. Results The elastic modulus was inversely derived by adopting this mature neural network with relatively less error. Conclusions The viability of the proposed methods for inverse derivative of elastic modulus was demonstrated in this paper, which could provide a simple and effective method to obtain mechanical parameters for clinic work.

Effect of partial ossicular prosthesis replacement on hearing restoration of human / 医用生物力学

Objective To study the postoperative effects on hearing restoration after different types of ossicular reconstruction with partial ossicular replacement prosthesis (PORP). Methods CT data of the right ear from a healthy volunteer were digitalized and imported into PATRAN software to reconstruct the 3D finite element model of the ear by a self compiling program. Dynamic analysis was conducted on the sound transmission to make comparison between the calculated results and experimental data. Results Results of the dynamic analysis for normal human ear were in good agreement with the experiment data, which confirmed the validity of the FE model. At the frequency between 0.1~10 kHz, hearing restoration with partial retaining the handle of malleus was better than that without retention after the replacement of PORP, and the value of hearing restoration was between 11.56~28.91 dB. The maximum stress of tympanic membrane with partial retaining the handle of malleus was less than that without retaining. At the frequency between 0.1~0.6 kHz as well as between 2~10 kHz, better hearing restoration was obtained when the thickness of the cartilage slice was 2.0 mm. At the frequency between 0.6~2 kHz, better hearing restoration was obtained when the thickness of the cartilage slice was 0.1 mm. Conclusions For ossicular reconstruction with PORP, the effect of retaining the handle of malleus was much better than that without retaining. The effect of hearing restoration was better when the thickness of the cartilage placed between the tympanic membrane and the contact surface of the PORP was within the range of 0.1~2.0 mm.

Effect of different connecting methods for artificial ossicle on dynamic response of ear / 医用生物力学

Objective To study the effects of the different connecting mode of artificial ossicle on hearing restoration. Method Geometrical model of human ear was established by an original C++ program based on clinical CT data, and imported this geometrical model into finite element software PATRAN to build up the numerical finite element model of human ear structure. Based on the finite element model, the fluid solid coupling was computed by harmonic response analysis method, and the effect of sound conduction on ear structure was analyzed according to different implantable methods and positions of artificial ossicle. Results The validity of this numerical model is confirmed by comparing the amplitude of umbo and stapes footplate on numerical model which is gained by dynamic response analysis on normal ear structure with published experimental measurements on human temporal bones. ConclusionsConnecting artificial ossicle to tympanic membrane at its central position is optimal for the dynamic response of ear structure as the amplitude of stapes footplate under this situation is slightly higher than other connecting methods since it conforms to physiological function of human ear, and the effect of hearing recovery could be better.

Computer-aided Diagnosis of Gastric Carcinoma B ased on Feature Selection and Probability Neural Network / 现代生物医学进展

Based on signal to noise ratio and probabilistic neural network method associated with experimental data,all analysis model in gastric carcinoma is presented.According to the available information,the samples of gastric carcinoma can be tested and ana.Lyzed.The signal to noise ratio is first calculated．Secondly,records in the database are chosen as a training set to build a probabilistie neural network model and the feature subset is selected according to accuracy.Finally,test set is to test accuracy of model．The model is implemented using MATLAB,and it can be generalized and applied to similar disease auxiliary diagnosis region.

Computer-aided Diagnosis of Gastric Carcinoma B ased on Feature Selection and Probability Neural Network / 现代生物医学进展

Based on signal to noise ratio and probabilistic neural network method associated with experimental data,all analysis model in gastric carcinoma is presented.According to the available information,the samples of gastric carcinoma can be tested and ana.Lyzed.The signal to noise ratio is first calculated．Secondly,records in the database are chosen as a training set to build a probabilistie neural network model and the feature subset is selected according to accuracy.Finally,test set is to test accuracy of model．The model is implemented using MATLAB,and it can be generalized and applied to similar disease auxiliary diagnosis region.

Analysis of SOX4 gene mutation in non-small cell lung cancer tissues / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the mutation of SOX4 gene in the different tumor tissues with pathological stages and types of non-small cell lung cancer (NSCLC), and to explore its roles in the progression of lung carcinoma.</p><p><b>METHODS</b>The SOX4 gene HMG-box of lung cancer tissues and paracancerous tissues were amplified by PCR, 20 cases shown difference by single strand conformation polymorphyism analysis were sequenced. The DNA sequences were compared with normal sequences by software Clustal and DNAStar.</p><p><b>RESULTS</b>In the 90 NSCLCs, 18 cases were found with mutations of SOX4 gene and were sequenced, and there were 2 mutational points. Seven were detected from squamous cell carcinoma, five from adenocarcinoma and six from adeno-squamous. Three were obtained from tissues in stage I, five in stage II, six in stage III, and four in stage IV. The mutation rate in stage II, III and IV was significantly higher than that in stage I.</p><p><b>CONCLUSION</b>SOX4 gene mutation is not associated with pathology histological types of tumor, but it is significantly associated with pathological stages and the mutation rate increases gradually, which has relation with advanced pathological stages in NSCLC. The results indicate that the SOX4 gene mutations might be related in the lung carcinogenesis and tumor metastasis. The study also provides molecular data for study the links between the mutation of SOX gene and human oncogenesis.</p>