基于神经网络法反求耳结构弹性模量

目的通过耳结构的位移反算耳结构弹性模量。方法基于Patran软件建立耳结构有限元模型,使用Mat-lab建立计算耳结构反问题的BP神经网络。对耳结构有限元模型进行频率响应分析,得到鼓膜凸和镫骨足板的位移响应;把位移作为BP神经网络的输入、相对应的结构弹性模量作为输出,对网络进行训练。结果利用训练成熟的BP网络反算出耳结构的弹性模量,相对误差非常小。结论反算结果表明,所使用的反问题方法求解耳结构弹性模量是可行的,可为临床提供确定生物结构力学参数简捷有效的方法。     

Viscoelastic Properties of Human Tympanic Membrane

The tympanic membrane or eardrum of human ear transfers sound waves into mechanical vibration from the external ear canal into the middle ear and cochlea. Mechanical properties of the tympanic membrane (TM) play an important role in sound transmission through the ear. Although limited resources about linear elastic properties of the TM are available in literature, there is a lack of measurement or modeling of viscoelastic properties of the TM at low stress levels. In this study, the uniaxial tensile, stress relaxation, and failure tests were conducted on fresh human cadaver TM specimens to explore mechanical properties of the TM. The experimental results were analyzed using the hyperelastic Ogden model and digital image correlation method. The constitutive equation and non-linear elastic properties of the TM were presented by functions of the stress and strain at the stress range from 0 to 1 MPa. Viscoelastic properties of the TM were described by the stress relaxation function and hysteresis. The results show that the uniaxial tensile test with the aid of digital image correlation analysis is a reliable and useful approach for measuring mechanical properties of ear tissues. The data presented in this paper contribute to ear biomechanics in both experimental measurement and theoretical analysis of ear tissues.     

An elastic force-length relation for tympanic membrane implants--a preliminary report

An elastic force-length relation has been recorded for tympanic membrane implants. A model based on the fibre structure of these materials was used to obtain a value for their elastic modulus for tympanic membrane.     

温度对单个人红细胞膜力学特性的即时作用

目的：探讨温度对单个红细胞膜力学性质的即时影响。 方法： 利用静态显微图像分析技术和动态显微图像分析技术，在无损、实时、在位的情况下，观察和测量不同温度下单个人红细胞的形态、大小、膜弯曲弹性模量和剪切弹性模量的变化。 结果： 红细胞的接触面积和直径随温度的升高而减小，胞膜的弯曲弹性模量和剪切弹性模量都在生理温度37 ℃时最小，而温度低于或高于37 ℃时红细胞膜的弯曲弹性模量和剪切弹性模量都增大。 结论： 红细胞在生理温度37 ℃时有最好的形态和力学变形性，便于发挥其生理功能。     

Mechanical properties and histology of cortical bone from younger and older men.

Tensile breaking load, strength, strain, modulus of elasticity and density plus the histological structure at the fracture site, were determined for 207 standardized specimens of cortical bone from the embalmed femur, tibia, and fibula of 17 men from 36 to 75 years of age. The men were divided into a younger group (41.5 years old-avg)) and an older group (71 years old-avg). Specimens from younger men had a greater average breaking load, strength, strain, modulus and density than those from older men. The percentage of spaces in the break area was greater in specimens from older men, but specimens from younger men had a slightly greater percentage of osteons, osteon fragments, and interstitial lamellae. The number of osteons/mm2 and of osteon fragments/mm2 was greater in specimens from older men but the average area/osteon and area/osteon fragment was greater in specimens from younger men. Thus, there are quantitative and qualitative differences in the histological structure of bone from younger and older men. Differences in the tensile properties of bone from younger and older men can be explained by histological differences in the bone.     

Helen Wendler Deane. (1917–1966)

Tensile breaking load, strength, strain, modulus of elasticity and density plus the histological structure at the fracture site, were determined for 207 standardized specimens of cortical bone from the embalmed femur, tibia, and fibula of 17 men from 36 to 75 years of age. The men were divided into a younger group (41.5 years old-avg) and an older group (71 years old-avg). Specimens from younger men had a greater average breaking load, strength, strain, modulus and density than those from older men. The percentage of spaces in the break area was greater in specimens from older men, but specimens from younger men had a slightly greater percentage of osteons, osteon fragments, and interstitial lamellae. The number of osteons/mm² and of osteon fragments/mm² was greater in specimens from older men but the average area/osteon and area/osteon fragment was greater in specimens from younger men. Thus, there are quantitative and qualitative differences in the histological structure of bone from younger and older men. Differences in the tensile properties of bone from younger and older men can be explained by histological differences in the bone.     

Dynamic Properties of Human Tympanic Membrane After Exposure to Blast Waves

Blast overpressure causes dynamic damage to middle ear components, and tympanic membrane (TM) rupture is the most frequent middle ear injury. However, it is unclear how the blast waves change mechanical properties of the TM and affect sound transmission through the ear. This paper reports the current study on dynamic properties of the TM after exposure to blast waves by using acoustic loading and laser Doppler vibrometry (LDV). The TM specimens were prepared from human temporal bones following exposures to blast overpressure. Vibration of the TM specimen induced by acoustic loading was measured by LDV over a frequency range of 200–8000 Hz. An inverse-problem solving method with finite element modeling was used to determine the complex modulus of the TM specimen. The post-blast storage modulus ranged from 23.1 to 26.9 MPa, and loss modulus ranged from 0.09 to 3.78 MPa as frequency increased from 200 to 8000 Hz. Compared to the complex modulus of normal TM reported in the literature, the post-blast storage and loss modulus decreased significantly across the frequency range. The scanning electron microscopy (SEM) images of the post-blast TM samples showed microstructural changes of the tissue, which explained the alteration of mechanical properties of the TM samples.     

人耳鼓膜病变数值分析

目的研究鼓膜厚度和硬度对人耳传声的影响。方法利用CT获取志愿者耳部结构临床资料,使用Matlab软件提取相关结构的边界,将边界文件导入ANSYS建立人耳结构数值有限元模型。结果利用本文人耳数值模型,在外耳道口施加105dB声压,进行200～8000Hz频率范围的谐响应分析。以此研究在鼓膜病变情况下,鼓膜和镫骨底板位移幅值的变化规律。结论用数值方法解释了鼓膜病变对传声的影响,为鼓膜修补提供了力学参考。     

Three-Dimensional Finite Element Modeling of Human Ear for Sound Transmission

An accurate, comprehensive finite element model of the human ear can provide better understanding of sound transmission, and can be used for assessing the influence of diseases on hearing and the treatment of hearing loss. In this study, we proposed a three-dimensional finite element model of the human ear that included the external ear canal, tympanic membrane (eardrum), ossicular bones, middle ear suspensory ligaments/muscles, and middle ear cavity. This model was constructed based on a complete set of histological section images of a left ear temporal bone. The finite element (FE) model of the human ear was validated by comparing model-predicted ossicular movements at the stapes footplate and tympanic membrane with published experimental measurements on human temporal bones. The FE model was employed to predict the effects of eardrum thickness and stiffness, incudostapedial joint material, and cochlear load on acoustic-mechanical transmission through the human ossicular chain. The acoustic-structural coupled FE analysis between the ear canal air column and middle ear ossicles was also conducted and the results revealed that the peak responses of both tympanic membrane and stapes footplate occurred between 3000 and 4000 Hz.     

基于遗传算法反求耳结构弹性模量

本研究通过力学反问题原理,利用已知的位移求解耳结构弹性模量。随机产生遗传算法的初始种群,使用自编的Matlab算法程序,对初始种群进行遗传迭代计算,把已知的目标位移与种群位移的均方差作为目标函数,以目标函数值最小控制迭代进化的方向。通过耳结构的鼓膜凸和镫骨底板2个控制位移以及砧镫关节周围的8个控制位移这两个算例求解正常砧镫关节的弹性模量,并使用耳结构的鼓膜凸和镫骨底板2个控制位移求解病变砧镫关节的弹性模量。结果表明,使用基于遗传算法的反问题方法计算耳结构的弹性模量是可行的,并且具有稳定性和不受结构力学性能影响的特点,相对误差分别为0.05%和0.2%、0.03%,可为临床病变耳提供有效的力学参数。     

In vitro tympanic membrane position identification with a co-axial fiber-optic otoscope

Otitis media diagnosis can be assisted by measuring the shape of the tympanic membrane. We have developed an ear speculum for an otoscope, including spatially distributed source and detector optical fibers, to generate source-detector intensity matrices (SDIMs), representing the curvature of surfaces. The surfaces measured were a model ear with a latex membrane and harvested temporal bones including intact tympanic membranes. The position of the tympanic membrane was shifted from retracted to bulging by air pressure and that of the latex membrane by water displacement. The SDIM was normalized utilizing both external (a sheared flat plastic cylinder) and internal references (neutral position of the membrane). Data was fitted to a two-dimensional Gaussian surface representing the shape by its amplitude and offset. Retracted and bulging surfaces were discriminated for the model ear by the sign of the Gaussian amplitude for both internal and external reference normalization. Tympanic membranes were separated after a two-step normalization: first to an external reference, adjusted for the distance between speculum and the surfaces, and second by comparison with an average normally positioned SDIM from tympanic membranes. In conclusion, we have shown that the modified otoscope can discriminate between bulging and retracted tympanic membranes in a single measurement, given a two-step normalization.     

耳内镜下新西兰兔中耳的解剖研究

目的　耳内镜下观察兔中耳解剖结构,探讨兔作为耳内镜解剖训练模型的可行性,为兔中耳相关的其他实验研究提供解剖学依据。 方法　5只（10耳）新西兰兔麻醉处死后,耳内镜下经外耳道入路观察兔鼓膜、中耳鼓室结构,辨别听小骨、上中下鼓室、面神经等。 结果　与人对比,新西兰兔听小骨由锤砧联合体和镫骨组成;上鼓室外侧壁部分骨质缺如,由鼓膜向上延续并覆盖;听泡类似于人的中、下鼓室,包含咽鼓管、面神经、鼓岬、前庭窗、蜗窗以及鼓室神经等结构,乳突为听泡尾侧的板障型骨管;面神经鼓室段水平走行于上鼓室下方骨壁内,后经锥隆起垂直走行于听泡后壁,经茎乳孔出听泡。 结论　新西兰兔中耳结构与人相似,既可作为耳科医生练习耳内镜操作的解剖模型,也可作为耳部三维解剖结构的教学标本。     

Cholesterol Granuloma of the Tympanic Membrane Presenting as a Blue Eardrum

Intramembranous tympanic membrane cholesterol granuloma (CG) occurs infrequently. Here, the authors report a case of CG in the tympanic membrane presenting as a blue eardrum in the right ear. In addition, a pinhole perforation noted in the anterosuperior area revealed a brown discharge. High-resolution temporal bone CT showed a bulging mass shadow in the middle ear and a soft tissue dense lesion that filled both the epitympanum and mastoid cavity. Tympanomastoidectomy was performed under general anesthesia. New bone formation was confirmed in the mastoid antrum and epitympanum, and the epitympanum was blocked by new bone. The tympanic membrane revealed a round, brownish mass with a glistening surface and a severely thickened pars tensa. We herein report this case and review pertinent medical literature.     

耳内镜下新西兰兔中耳的解剖研究

目的　耳内镜下观察兔中耳解剖结构,探讨兔作为耳内镜解剖训练模型的可行性,为兔中耳相关的其他实验研究提供解剖学依据。 方法　5只（10耳）新西兰兔麻醉处死后,耳内镜下经外耳道入路观察兔鼓膜、中耳鼓室结构,辨别听小骨、上中下鼓室、面神经等。 结果　与人对比,新西兰兔听小骨由锤砧联合体和镫骨组成;上鼓室外侧壁部分骨质缺如,由鼓膜向上延续并覆盖;听泡类似于人的中、下鼓室,包含咽鼓管、面神经、鼓岬、前庭窗、蜗窗以及鼓室神经等结构,乳突为听泡尾侧的板障型骨管;面神经鼓室段水平走行于上鼓室下方骨壁内,后经锥隆起垂直走行于听泡后壁,经茎乳孔出听泡。 结论　新西兰兔中耳结构与人相似,既可作为耳科医生练习耳内镜操作的解剖模型,也可作为耳部三维解剖结构的教学标本。     

胰蛋白酶对红细胞膜动态力学特性的影响

目的： 研究胰蛋白酶对人红细胞膜表面电荷密度及动态力学特性的影响。 方法： 用密度梯度离心法从健康成人血液中分离出“青年”和“老年”红细胞，37 ℃下与不同浓度的胰蛋白酶孵育60 min。利用Zeta电位分析仪测量红细胞膜表面电荷密度，利用快速显微动态图像分析技术测定单个活态红细胞的大小、形态和细胞膜弯曲弹性模量（Kc）和剪切弹性模量（μc）。 结果： （1）正常和用胰蛋白酶处理后“老年”红细胞的表面电荷密度分别显著小于正常和用胰蛋白酶处理后的“青年”红细胞（P<0.01）。（2）正常“青年”红细胞和正常“老年”红细胞在形态上没有显著区别，但正常“老年”红细胞的接触面积显著小于正常“青年”红细胞（P<0.01）；胰蛋白酶处理可减小红细胞的大小，但对形状规化因子没有显著影响。（3）正常“老年”红细胞膜Kc和μc均显著大于正常“青年”红细胞（P<0.05）；“青年”和“老年”红细胞膜Kc和μc均随胰蛋白酶浓度的增加而增大。结论： 胰蛋白酶处理可降低“青年”和“老年”红细胞膜表面电荷密度，增加红细胞膜的弯曲弹性模量，从而降低红细胞膜的力学变形性。     

Material model measurements and predictions for a random pore poly(epsilon-caprolactone) scaffold

We investigated material models for a polymeric scaffold used for bone. The material was made by co-extruding poly(epsilon-caprolactone) (PCL), a biodegradable polyester, and poly(ethylene oxide) (PEO). The water soluble PEO was removed resulting in a porous scaffold. The stress-strain curve in compression was fit with a phenomenological model in hyperbolic form. This material model will be useful for designers for quasi-static analysis as it provides a simple form that can easily be used in finite element models. The ASTM D-1621 standard recommends using a secant modulus based on 10% strain. The resulting modulus has a smaller scatter in its value compared with the coefficients of the hyperbolic model, and it is therefore easier to compare differences in material processing and ensure quality of the scaffold. A prediction of the small-strain elastic modulus was constructed from images of the microstructure. Each pixel of the micrographs was represented with a brick finite element and assigned the Young's modulus of bulk PCL or a value of 0 for a pore. A compressive strain was imposed on the model and the resulting stresses were calculated. The elastic constants of the scaffold were then computed with Hooke's law for a linear-elastic isotropic material. The model was able to predict the small-strain elastic modulus measured in the experiments to within one standard deviation. Thus, by knowing the microstructure of the scaffold, its bulk properties can be predicted from the material properties of the constituents.     

Morphological studies of postnatal changes of the sound transport apparatus in the middle ear of humans and rabbits

The dimensions of the tympanic membrane and middle ear ossicles, respectively, were measured, in order to investigate the postnatal development of sound transport function. In human we observed only a small increase of the tympanic membrane area between the 7th postconceptional month and the 32nd year of life. This growth has no functional effect on the sound transport. In contrast, in rabbits all measured parameters with the exception of the stapes plate area show an increase until the 12th day of life. Thus, the amplification factor doubles in this species during the first 2 weeks of life. The temporal parallelism of the middle ear development with the ontogenesis of the acoustic function seems to exist in humans, but does not in rabbits.     

Microvascular networks in tympanic membrane,malleus periosteum,and annulus perichondrium of neonatal mongrel dog: A vasculoanatomic model for surgical considerations

India-ink-imaged blood-vessel networks in cleared tympanic membranes and adnexa from ten neonatal dogs were examined microscopically and photographed. The major significance of the study lies in documentation of a dual source of arterial supply, a bilaminar relationship of arterial and venous plexuses intrinsic to the tympanic membrane, and a consistent major venous pathway relative to a definite locus (pars flaccida of the membrane). Illustration of all three types of blood pathways (arteries, veins, and capillaries) provides new vasculoanatomic data that are essential to ear surgery, specifically—to myringotomies and myringoplasties. A comparison was made between dog and human tympanic membrane structures and their arterial supplies. Close similarities suggested that dog tympanic membrane might serve as a suitable model for development of innovative surgical procedures and as a model for rehearsal of difficult techniques. The results of this investigation provide a valuable caveat to otologists.     

髋关节软骨高、低负重区微纳结构的力学性质对比

文题释义：微纳层面：相对于宏观层面而言,是对宏观层面的一个补充,由肉眼可见的毫米级别到肉眼不可见的微米、纳米级别。分别使用微米级、纳米级原子力显微镜探针测量软骨微纳弹性模量,以揭示软骨在微纳层面力学性能的特点,以及与宏观层面力学性能的关系。 负重区：在日常活动运动中,由于机体力线等不同,势必造成软骨不同区域负重出现不同,不同的负重也会影响到胶原纤维等物质的重塑重构,引起软骨力学性能的改变。 背景：髋关节软骨具有高、低负重区域,既往研究表明2个区域的宏观弹性模量是不同的。然而在微米和纳米水平上的弹性模量尚不清楚,这些信息对于进一步理解软骨微米和纳米力学性质至关重要。此外,影响软骨2个区域机械性能的微纳结构至今仍有待阐明。 目的：探究微纳层面髋关节软骨高、低负重区力学性质与结构。 方法：取新鲜正常猪股骨头软骨,使用原子力显微镜直径为5 μm的球形尖端测量不同负重区微米级压缩弹性模量,使用曲率半径为5 nm的ScanAsyst-Air探针测量其纳米级压缩弹性模量、纳米结构和胶原纤维直径。扫描电子显微镜用于识别软骨不同负重区微米结构。 结果与结论：①股骨头软骨高负重区微米级弹性模量为(433.05±146.52) kPa,低负重区微米级弹性模量为(331.19±84.88) kPa,高负重区域在微米水平上的压缩弹性模量显著高于低负重区域(P=0.029 8);②股骨头软骨高负重区纳米级弹性模量为(1.24±0.42) GPa,低负重区纳米级弹性模量为(1.28±0.41) GPa,在纳米水平上2个区域的胶原纤维的压缩弹性模量差异无显著性意义(P=0.846 2);③在微米水平上,股骨头软骨高负重区域的胶原纤维排列更规则;在纳米水平上,2个负重区域的胶原纤维直径差异无显著性意义(P=0.926 4);④以上结果表明,股骨头软骨高负重区胶原纤维较低负重区交联更规则,使软骨高负重区微米级压缩弹性模量高于低负重区,与宏观上压缩弹性模量趋势一致,但高负重并没有影响到纳米层面单个胶原纤维。 ORCID: 0000-0001-7971-5372(郭江博) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程