The interaction shear force between internal interstitial fluid motion and the solid circumferential-longitudinal medial lamellae helps generate the shear stress involved in dissection of human ascending aorta aneurysmal or non-pathologic tissue. Frequency analysis parameters from the total shear stress versus time response to translational 1 Hz sinusoidal shear deformation over 50 cycles measure the interaction with respect to the three factors: tissue type, sinusoidal deformation amplitude and direction of the shear deformation. Significant 1, 3, and 5 Hz components exist in this order of descending magnitude for shear deformation amplitudes of either 25% or 50% of the specimen length. Evaporation tests indicate that the amount of free water in both aneurysmal and non-pathological tissue is nearly the same. The interstitial fluid–solid interaction under shear deformation is visible in the shoulders of the total shear stress versus time response curve that are caused by the 3 Hz component. During a single deformation cycle, the ratio of the amplitudes of the 3 Hz and the 1 Hz components measures the normalized amount of interaction. Under translational sinusoidal shear deformation at 25% amplitude, this interaction ratio is statistically smaller in non-pathologic than in aneurysmal human ascending aortic tissue in the circumferential direction. The frequency analysis parameters provide evidence that the structural changes in aneurysmal tissue induce an increase in the interstitial fluid–medial solid interaction shear force which contributes to the propensity for aneurysmal rupture.

Statement of significance

Circumferential shear force between the interstitial fluid and medial lamellae within the human ascending aortic wall is demonstrably greater in aneurysmal than non-pathologic tissue. This force likely increases with medial elastin degeneration and may facilitate the dissection propensity in aneurysmal tissue. The 3 Hz component in frequency analyses of the total shear stress versus time curve produced by 1 Hz sinusoidal translational shear deformation measures the fluid-solid interaction shear force that is otherwise difficult to isolate. This non-standard examination of the interstitial fluid interaction helps clarify clinical mechanical implications of structural differences between aneurysmal and non-pathologic human ascending aortic tissue. The aneurysmal dissection susceptibility does not appear to depend on the amount of interstitial fluid or the wall thickness compared to non-pathologic tissue.

中文翻译：

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平移正弦剪切变形下动脉瘤和非病理性人类升主动脉组织内的间质液固相互作用。

内部组织液运动与固体周向内侧薄片之间的相互作用剪切力有助于产生涉及人升主动脉瘤或非病理性组织解剖的剪切应力。从总剪切应力与时间的响应到50个周期的平移1 Hz正弦剪切变形的频率分析参数可测量与以下三个因素的相互作用：组织类型，正弦形变幅度和剪切变形的方向。对于剪切变形幅度为样品长度的25％或50％而言，显着的1、3和5 Hz分量以降序排列。蒸发测试表明，动脉瘤和非病理组织中的游离水量几乎相同。在总剪切应力与时间响应曲线（由3 Hz分量引起）的肩膀上可以看到剪切变形下的组织液-固体相互作用。在单个变形周期中，3 Hz分量和1 Hz分量的振幅之比可测量标准化的相互作用量。在平缓的正弦剪切变形（幅度为25％）下，非病理学上的这种相互作用比在统计学上要比人类动脉瘤在圆周方向上的升主动脉组织要小。频率分析参数提供了证据，证明动脉瘤组织的结构变化会引起间质液-固体固相相互作用剪切力的增加，从而导致动脉瘤破裂的倾向。

重要声明

在人的升主动脉壁内，组织液和内层板之间的周向剪切力在动脉瘤中明显大于非病理组织。该力可能随着弹性蛋白内侧变性而增加，并可能促进动脉瘤组织中的剥离倾向。由1 Hz正弦平移剪切变形产生的总剪切应力与时间曲线的频率分析中的3 Hz分量测量了流体-固体相互作用的剪切力，否则很难分离。间质液相互作用的这种非标准检查有助于阐明动脉瘤和非病理性人类升主动脉组织之间结构差异的临床机械意义。