RESUMEN
Plastic particle pollution has threatened the well-being of seawater ecosystems over the past decades. Therefore, understanding, modeling and (potentially) predicting the dynamics of microplastics and biogenic particles in ocean turbulence is of utmost importance to help develop mitigation strategies and propose technological solutions ultimately aimed at safeguarding global water systems. This is particularly significant for microplastics in the upper-ocean layer. To that end, this work presents a comprehensive and openly accessible dataset carefully designed to explore the interplay between the flow physics of particle-laden turbulence and the physicochemical effects of biofilm stickiness. The dataset comprises nine point-particle direct numerical simulations of fluid flow featuring microplastic and biogenic debris within a periodic three-dimensional flow domain. In all cases, the chosen turbulent intensity and microparticle properties represent conditions observed in the upper-ocean layer. This data repository aims to facilitate in-depth exploration, modeling and prediction of the intricate flow physics observed in marine microplastics, particularly regarding their distribution and aggregation.
RESUMEN
UNLABELLED: Instrument breakage during treatment can lead to serious complications and carries the risk of treatment failure. When a file breaks in the canal, bypassing or removal can be difficult and the long-term prognosis of the tooth may be compromised. Sometimes surgery may be indicated for removal of the broken segment. Often some part of the root cannot be cleaned because of blockage by the broken file. This report presents a specific approach in non- surgical removal of a broken file from a maxillary lateral incisor with a buccal sinus tract and a broken instrument in the apical third which was partially over extended into the periapical lesion. The broken file was accessed through the sinus tract and pushed into the canal. The canal was cleaned and shaped, filled with mineral trioxide aggregate (MTA). CONCLUSION: A sinus tract can be a specific path to reach the root tip and get access to remove the foreign materials pushed beyond the root canal space.
RESUMEN
UNLABELLED: Dens invagination is a developmental anomaly requiring specific treatment approaches. Oehler's Type III dens in dente, extends into the root and perforates at the apical area or lateral surface of the root. In this case endodontic treatment of the invaginated tooth was carried out through the central lumen of the invagination with calcium hydroxide without manipulation of the main pulp canal, thereby leaving the tooth vital. The 18-month follow-up examinations were indicative of treatment success; the periapical lesion resolved completely and the tooth remained vital. CONCLUSION: Information about the three dimensional anatomy of the teeth especially those with an abnormality is necessary for a successful treatment.
RESUMEN
When a barotropic shear layer becomes unstable, it produces the well-known Kelvin-Helmholtz instability (KHI). The nonlinear manifestation of the KHI is usually in the form of spiral billows. However, a piecewise linear shear layer produces a different type of KHI characterized by elliptical vortices of constant vorticity connected via thin braids. Using direct numerical simulation and contour dynamics, we show that the interaction between two counterpropagating vorticity waves is solely responsible for this KHI formation. We investigate the oscillation of the vorticity wave amplitude, the rotation and nutation of the elliptical vortex, and straining of the braids. Our analysis also provides a possible explanation for the formation and evolution of elliptical vortices appearing in geophysical and astrophysical flows, e.g., meddies, stratospheric polar vortices, Jovian vortices, Neptune's Great Dark Spot, and coherent vortices in the wind belts of Uranus.