Periodic ER-plasma membrane junctions support long-range Ca signal integration in dendrites.

Neuronal dendrites must relay synaptic inputs over long distances, but the mechanisms by which activity-evoked intracellular signals propagate over macroscopic distances remain unclear. Here, we discovered a system of periodically arranged endoplasmic reticulum-plasma membrane (ER-PM) junctions tiling the plasma membrane of dendrites at ∼1 μm intervals, interlinked by a meshwork of ER tubules patterned in a ladder-like array. Populated with Junctophilin-linked plasma membrane voltage-gated Ca channels and ER Ca-release channels (ryanodine receptors), ER-PM junctions are hubs for ER-PM crosstalk, fine-tuning of Ca homeostasis, and local activation of the Ca/calmodulin-dependent protein kinase II.

Automatic three-dimensional analysis of posterosuperior full-thickness rotator cuff tear size on MRI.

Background: Tear size and shape are known to prognosticate the efficacy of surgical rotator cuff (RC) repair however, current manual measurements on magnetic resonance images (MRI), exhibit high interobserver variabilities and exclude three-dimensional (3D) morphological information. This study aimed to develop algorithms for automatic 3D analyses of posterosuperior full-thickness RC tear to enable efficient and precise tear evaluation and 3D tear visualization.

Methods: - A deep-learning network for automatic segmentation of the tear region in coronal and sagittal multicenter MRI was trained with manually segmented (consensus of 3 experts) pd- and T2 weighted MRI of shoulders with full-thickness posterosuperior tears (n=200).

The force has limits: Molecular motors in robotics.

Molecular motors generate force to individually power molecular machines or collectively drive macroscopic actuators. The force output of molecular and macroscale motors appears to be constrained by the same scaling law relating motor force and mass. Here, potential origins of these universal performance characteristics are discussed and the implications examined.

Mechanical fatigue in microtubules.

Mechanical failure of biological nanostructures due to sustained force application has been studied in great detail. In contrast, fatigue failure arising from repeated application of subcritical stresses has received little attention despite its prominent role in engineering and potentially biology. Here, paclitaxel-stabilized microtubules are up to 256 times bent into sinusoidal shapes of varying wavelength and the frequency of breaking events are observed.

Heat strain in different hot environments hiking in wildland firefighting garments.

Wildland firefighters can work at high intensity in hot environments for extended periods of time. The resulting heat strain may be modified by the environmental conditions (i.e.