AI 中文总结
本研究通过构建活性黏弹性连续介质模型，揭示活性组织的确定型、不确定型、比例型生长由活性应力与弹性模量的比值及机械阻抗决定，统一于同一力学框架。
AI 中文摘要
生长可能在达到目标大小时停止，或持续终生：即确定型与不确定型表型。我们开发了沿单轴生长组织的活性黏弹性连续介质模型，其中细胞分裂与死亡产生活性应力。我们发现两种渐近状态：其一为组织达到由其材料参数决定的相对尺寸，其二为组织无界线性伸长。实现哪种状态由活性应力与弹性模量的比值决定。该转变源于组织可承受的弹性应力的限制：足够大的活性永远无法被平衡。在由不同材料属性部分构成的组织中，生长阶段会稳定在固定长度比例，该比例由各部分的机械阻抗而非遗传因素决定；使阻抗与初始长度匹配可保留组织初始的比例。因此，确定型、不确定型与比例型生长是同一连续介质力学框架的不同状态。
英文摘要
Growth may cease at a target size or continue throughout life: the determinate and indeterminate phenotypes. We develop an active viscoelastic continuum model of a tissue growing along one axis, in which cell division and death generate active stresses. We find two asymptotic states: one in which the tissue reaches a relative size fixed by its material parameters, and one in which it elongates linearly without bound. Which state is realised is set by the ratio of active stress to elastic modulus. The transition originates in a bound on the elastic stress the tissue can support: a sufficiently large activity can never be balanced. In a tissue made of parts with different material properties, the growing phase settles into fixed length proportions, set by the mechanical impedances of the parts rather than inherited; matching impedances to initial lengths preserves the proportions the tissue began with. Determinate, indeterminate and proportionate growth thus appear as regimes of one continuum mechanical framework.
