AI 中文总结
研究针对标准活性布朗运动未考虑精子内在振荡的问题，提出振荡活性布朗运动模型，给出相关可观测量解析表达式及核心预测，利用人类精子轨迹推断参数，能定量再现精子轨迹和动力学，为描述精子运动性提供框架。
AI 中文摘要
活性生物微游动体通常将持续的自我推进与鞭毛或纤毛跳动产生的循环运动相结合。然而，标准活性布朗运动（ABM）没有明确考虑这些内在振荡。这一限制对精子细胞尤为重要，其运输不仅取决于方向持续性和随机重新定向，还取决于周期性头部运动。在此我们引入振荡活性布朗运动（OABM），它是ABM的最小扩展，其中游动体方向在受周期性角驱动调制时经历方向扩散。该模型给出了实验相关可观测量的解析表达式，包括时间平均均方位移、速度自相关函数和横向偏移幅度。一个核心预测是两种弹道 regime 之间的交叉：由游动速度主导的短时间运动和由角跳动幅度决定的振荡平均有效速度降低的中间 regime。利用人类精子轨迹，我们从标准运动性测量中推断模型参数。该模型在对照条件下以及诱导超激活后，定量再现了单细胞轨迹和群体水平动力学。总体而言，OABM提供了一个紧凑的活性物质框架，将可测量的鞭毛运动学与粗粒度运输联系起来，能够描述不同生理状态下的精子运动性。
英文摘要
Active biological microswimmers typically combine persistent self-propulsion with cyclic motion generated by flagellar or ciliary beating. However, standard active Brownian motion (ABM) does not explicitly account for these intrinsic oscillations. This limitation is particularly relevant for sperm cells, whose transport depends not only on directional persistence and stochastic reorientation but also on periodic head motion. Here we introduce oscillatory active Brownian motion (OABM), a minimal extension of ABM in which the swimmer orientation undergoes directional diffusion while being modulated by a periodic angular drive. The model yields analytical expressions for experimentally relevant observables, including the time-averaged mean-squared displacement, velocity autocorrelation function, and transverse excursion amplitude. A central prediction is a crossover between two ballistic regimes: short-time motion governed by the swimming velocity and an intermediate regime with a reduced, oscillation-averaged effective velocity determined by the angular beat amplitude. Using trajectories of human sperm, we infer model parameters from standard motility measures. The model quantitatively reproduces both single-cell trajectories and population-level dynamics under control conditions and following induction of hyperactivation. Overall, OABM provides a compact active-matter framework that links measurable flagellar kinematics to coarse-grained transport, enabling a description of sperm motility across different physiological states.
Comments21 pages, 5 figures
