人体后直肠的表征揭示了机械和结构上的异质性
Thomas Whitehead-Clarke1, Christopher Brown2, Geetika Ail3
1Centre for 3D Models of Health and Disease, Division of Surgery and Interventional Science, University College London, UK.
Clinical biomechanics (Bristol, Avon)
|May 27, 2023
概括
后直肠在横平面上比纵平面在机械上更强大,更硬. 原纤维是横向组织的,有助于这种异构的机械性质.
科学领域:
- 生物力学 生物力学
- 人体解剖学 解剖学 解剖学
- 材料科学 材料科学 材料科学
背景情况:
- 人的直肠是一个重要的解剖结构.
- 了解其机械性能对于手术和重建手术至关重要.
研究的目的:
- 为了研究人类后直肠外的机械特性 (最终的拉力应力,刚性,厚度,异构性).
- 用第二子 (SHG) 显微镜评估原纤维组织.
主要方法:
- 在来自6个尸体捐赠者的25个后直肠外样本上进行单轴拉伸应力测试.
- 测试是在横 (n=15) 和纵 (n=10) 平面进行的.
- 使用SHG显微镜分析了原纤维组织在10个后部和3个前部直肠外样本上.
主要成果:
- 在横平面上,相比于纵平面 (P < 0.01),后方直直体外套的最终拉力应力 (7.7 MPa 与 1.2 MPa 相比) 和扬模量 (11.1 MPa 与 1.7 MPa) 在横平面上显著更高 (P < 0.01).
- 后直肠的平均厚度为0.51毫米 (SD 0.13).
- 通过SHG显微镜检测到,在后内有横向对齐的原纤维.
结论:
- 后方直肠表现出显著的机械和结构异质性.
- 由于原纤维的组织,其机械强度和刚性在横平面上更大.
- 这些发现为了解腹壁机制提供了有价值的数据.
相关概念视频
Relation between Poisson's ratio, Modulus of Elasticity and Modulus of Rigidity
302
Deformation occurs in axial and transverse directions when an axial load is applied to a slender bar. This deformation impacts the cubic element within the bar, transforming it into either a rectangular parallelepiped or a rhombus, contingent on its orientation. This transformation process induces shearing strain. Axial loading elicits both shearing and normal strains. Applying an axial load instigates equal normal and shearing stresses on elements oriented at a 45° angle to the load axis.
302
Deformation in a Circular Shaft
391
One of the distinctive characteristics of circular shafts is their ability to maintain their cross-sectional integrity under torsion. In other words, each cross-section continues to exist as a flat, unaltered entity, simply rotating like a solid, rigid slab. To understand the distribution of shearing stress within such a shaft, consider a cylindrical section inside this circular shaft. This section has a length of L and a radius of R, with one end fixed. The radius of the cylindrical section is...
391
Bending of Members Made of Several Materials
233
In analyzing a structural member composed of two different materials with identical cross-sectional areas, it is crucial to understand how their distinct elastic properties affect the member's response under load. The analysis involves assessing stress and strain distributions using the transformed section concept, which accounts for variations in material properties.
Hooke's Law determines stress in each material, stating that stress is proportional to strain but varies due to each...
Hooke's Law determines stress in each material, stating that stress is proportional to strain but varies due to each...
233
Deformations in a Transverse Cross Section
285
When a material is subjected to uniaxial stress, it elongates or contracts in the direction of the applied force, and also undergoes changes in the perpendicular directions. This behavior is crucial for understanding how materials behave under stress and is governed by mechanical properties such as Poisson's ratio v, which measures the ratio of transverse strain to axial strain.
As the material stretches, it expands or contracts in orthogonal directions to the load. This phenomenon varies...
As the material stretches, it expands or contracts in orthogonal directions to the load. This phenomenon varies...
285
Thin-Walled Hollow Shafts
217
In analyzing a thin-walled hollow shaft subjected to torsional loading, a segment with width dx is isolated for examination. Despite its equilibrium state, this segment faces torsional shearing forces at its ends. These forces are quantitatively described by the product of the longitudinal shearing stress on the segment's minor surface and the area of this surface, leading to the concept of shear flow. This shear flow is consistent throughout the structure, indicating a uniform distribution...
217
Normal Strain under Axial Loading
586
Normal strain under axial loading is an important concept in the field of mechanics of materials. Axial loading implies the application of a force along the axis of a material, like a column or bar. This force can either compress or stretch the material. In the context of axial loading, normal strain is the deformation experienced by the material in the direction of the loading force. It's calculated as the change in length divided by the original length of the material. This unitless ratio...
586


