Analysis of root-environment interactions reveals mechanical advantages of growth-driven penetration of roots.

Plant roots are considered highly efficient soil explorers. As opposed to the push-driven penetration strategy commonly used by many digging organisms, roots penetrate by growing, adding new cells at the tip, and elongating over a well-defined growth zone. However, a comprehensive understanding of the mechanical aspects associated with root penetration is currently lacking.

Spatiotemporal variability after stroke reflects more than just slow walking velocity.

Background: Increased spatiotemporal gait variability is considered a clinical biomarker of ageing and pathology, and a predictor of future falls. Nevertheless, it is unclear whether the increased spatiotemporal variability observed in persons with stroke is directly related to the pathology or simply reflects their choice of walking velocity.

Research Question: Does increased spatiotemporal gait variability directly relate to motor coordination deficits after stroke?

Methods: Forty persons with stroke participated in this cross-sectional study.

Physical Activity, Social Participation, and Pain Outcomes Among Community-Dwelling Older Adults.

Background: Little is known regarding the effect of social participation (SP) and physical activity (PA) on pain outcomes among community-dwelling older adults in the United States.

Aims: To determine whether SP and PA are associated with pain outcomes (bothersome pain and number of pain sites).

Design: Guided by the biopsychosocial model of chronic pain for older adults, we analyzed data from 7,187 community dwelling participants in the National Health and Aging Trends Study.

Inference of long-range cell-cell force transmission from ECM remodeling fluctuations.

Cells sense, manipulate and respond to their mechanical microenvironment in a plethora of physiological processes, yet the understanding of how cells transmit, receive and interpret environmental cues to communicate with distant cells is severely limited due to lack of tools to quantitatively infer the complex tangle of dynamic cell-cell interactions in complicated environments. We present a computational method to systematically infer and quantify long-range cell-cell force transmission through the extracellular matrix (cell-ECM-cell communication) by correlating ECM remodeling fluctuations in between communicating cells and demonstrating that these fluctuations contain sufficient information to define unique signatures that robustly distinguish between different pairs of communicating cells. We demonstrate our method with finite element simulations and live 3D imaging of fibroblasts and cancer cells embedded in fibrin gels.