Large mechanical properties enhancement in ceramics through vacancy-mediated unit cell disturbance.

Tailoring vacancies is a feasible way to improve the mechanical properties of ceramics. However, high concentrations of vacancies usually compromise the strength (or hardness). We show that a high elasticity and flexural strength could be achieved simultaneously using a nitride superlattice architecture with disordered anion vacancies up to 50%.

Design of Laves phase-reinforced compositionally complex alloy.

Topologically close-packed (TCP) phases such as Laves phases are usually considered to harm the mechanical properties of classical superalloys for high-temperature applications. However, if an optimal fraction and size are designed, this situation can completely change for some compositionally complex alloys (CCA). Based on existing studies on austenitic or ferritic steels, we propose in this paper a design strategy aimed at exploiting the role of the Laves phase in defining the mechanical properties of wrought CCAs at elevated temperatures.

Mapping Shear Bands in Metallic Glasses: From Atomic Structure to Bulk Dynamics.

A deep understanding of the mechanisms controlling shear banding is of fundamental importance for improving the mechanical properties of metallic glasses. Atomistic simulations highlight the importance of nanoscale stresses and strains for shear banding, but corresponding experimental proofs are scarce due to limited characterization techniques. Here, by using precession nanodiffraction mapping in the transmission electron microscope, the atomic density and strain distribution of an individual shear band is quantitatively mapped at 2 nm resolution.

Sinus Node Dysfunction, Atrial Arrhythmias, and the Sinus Node Microcirculation.

A patient with sinus node dysfunction (SND) developed atrial arrhythmias that were abolished after avoidance of nonsteroidal anti-inflammatory medication and by the institution of a deliberate, modest increase in blood pressure, suggesting that there was a vascular component to the rhythm disturbance. Published anatomical evidence for a unique sinus node microcirculation substantiates the premise that SND may be sensitive to arterial flow. Because physicians have been unaware of the presence of a unique sinus node microcirculation, recognition of its presence may alter the approach to treatment of patients with SND and atrial arrhythmias, particularly in the elderly and those with diabetes.