Reciprocal impulses of junctional origin causing trigeminy.

Reciprocal impulses of junctional origin were seen in a patient with left isomerism who had undergone Kawashima repair in infancy. Heterotaxy syndromes are associated with disturbances in sinus node function. Junctional rhythm is hence common in this group. Junctional rhythm can conduct both anterogradely, to the ventricles, and retrogradely, back to the atrium. When it conducts retrogradely, it is termed as atrial echo, which can further conduct back to the ventricle. Our patient had a junctional rhythm with atrial echo beats that conduct to the ventricle, along with an ectopic atrial focus that does not conduct to the ventricle. This is due to variation in the RP interval [between R wave and subsequent P wave] of the echo beat and the atrial ectopic beat with respect to the preceding QRS complex. The timing of the P wave after the QRS complex determines the refractoriness of the atrioventricular node. This exhibits a trigeminal rhythm in our patient.

MXene-Based Nanocomposites for Piezoelectric and Triboelectric Energy Harvesting Applications.

Due to its superior advantages in terms of electronegativity, metallic conductivity, mechanical flexibility, customizable surface chemistry, etc., 2D MXenes for nanogenerators have demonstrated significant progress. In order to push scientific design strategies for the practical application of nanogenerators from the viewpoints of the basic aspect and recent advancements, this systematic review covers the most recent developments of MXenes for nanogenerators in its first section. In the second section, the importance of renewable energy and an introduction to nanogenerators, major classifications, and their working principles are discussed. At the end of this section, various materials used for energy harvesting and frequent combos of MXene with other active materials are described in detail together with the essential framework of nanogenerators. In the third, fourth, and fifth sections, the materials used for nanogenerators, MXene synthesis along with its properties, and MXene nanocomposites with polymeric materials are discussed in detail with the recent progress and challenges for their use in nanogenerator applications. In the sixth section, a thorough discussion of the design strategies and internal improvement mechanisms of MXenes and the composite materials for nanogenerators with 3D printing technologies are presented. Finally, we summarize the key points discussed throughout this review and discuss some thoughts on potential approaches for nanocomposite materials based on MXenes that could be used in nanogenerators for better performance.