Capillary-Based Microfluidics-Coflow, Flow-Focusing, Electro-Coflow, Drops, Jets, and Instabilities.

Capillary-based microfluidics is a great technique to produce monodisperse and complex emulsions and particulate suspensions. In this review, the current understanding of drop and jet formation in capillary-based microfluidic devices for two primary flow configurations, coflow and flow-focusing is summarized. The experimental and theoretical description of fluid instabilities is discussed and conditions for controlled drop breakup in different modes of drop generation are provided. Current challenges in drop breakup with low interfacial tension systems and recent progress in overcoming drop size limitations using electro-coflow are addressed. In each scenario, the physical mechanisms for drop breakup are revisited, and simple scaling arguments proposed in the literature are introduced.

Whipping of electrified liquid jets.

We apply an electric field to a moderately conducting liquid surrounded by another coflowing liquid, all inside a glass-based microfluidic device, to study nonaxisymmetric instabilities. We find that the bending of the electrified jet results in a steady-state, helicoidal structure with a constant opening angle. Remarkably, the characteristic phase speed of the helicoidal wave only depends on the charge carried by the jet in the helicoidal region and its stability critically depends on the properties of the coflowing liquid. In fact, the steady-state helical structure becomes chaotic when the longest characteristic time is that of the inner liquid rather than that of the outer coflowing liquid. We also perform a numerical analysis to show that the natural preference of the jet is to adopt the conical helix structure observed experimentally.

Glass-Based Devices to Generate Drops and Emulsions.

In this manuscript, three different step-by-step protocols to generate highly monodisperse emulsion drops using glass-based microfluidics are described. The first device is built for the generation of simple drops driven by gravity. The second device is designed to generate emulsion drops in a coflowing scheme. The third device is an extension of the coflowing device with the addition of a third liquid that acts as an electric ground, allowing the formation of electrified drops that subsequently discharge. In this setup, two of the three liquids have an appreciable electrical conductivity. The third liquid mediates between these two and is a dielectric. A voltage difference applied between the two conducting liquids creates an electric field that couples with hydrodynamic stresses of the coflowing liquids, affecting the jet and drop formation process. The addition of the electric field provides a path to generate smaller drops than in simple coflow devices and for generating particles and fibers with a wide range of sizes.

Ultrathin Double-Shell Capsules for High Performance Photon Upconversion.

Triplet-fusion-based photon upconversion capsules with ultrathin double shells are developed through a single dripping instability in a microfluidic flow-focusing device. An inner separation layer allows use of a brominated hydrocarbon oil-based fluidic core, demonstrating significantly enhanced upconversion quantum yield. Furthermore, a perfluorinated photocurable monomer serves as a transparent shell phase with remote motion control through magnetic nanoparticle incorporation.

[Correlation between active anterior rhinomanometry and nasal endoscopy]. / Correlación entre la rinomanometría anterior activa y la endoscopia nasal.

OBJECTIVE: Nasal permeability is related to functional and anatomical parameters, which are objectified by active anterior rhinomanometry (AARNM). The study aims to compare alterations visualized through Nasal Endoscopy (NE) with nasal flow parameters in AARNM. MATERIAL AND METHODS: We carried out a prospective observational study of 45 patients suffering from nasal obstruction and septal deviation. They were explored through AARNM and NE, and the deviations were classified into anterosuperior and anteroinferior quadrants. The degree of agreement between observers and the validity of the diagnostic test was then analyzed. RESULTS: A sensitivity of 74.6% and a specificity of 60.5% were obtained comparing AARNM and EN globally. CONCLUSION: A reduced flow of the expiratory phase is correlated to inferior obstructions observed through NE. In the narrow nasal vestibule this correlation is not predictive.

Correlación entre la rinomanometría anterior activa y la endoscopia nasal / Correlation between active anterior rhinomanometry and nasal endoscopy

Objetivo: La permeabilidad nasal se correlaciona con unos parámetros funcionales y anatómicos, que se objetivan mediante la rinomanometría anterior activa (RNMAA). Objetivo: Se pretende comparar las alteraciones visualizadas mediante endoscopia nasal (EN) con los parámetros de la RNMAA. Material y métodos: Se realiza un estudio observacional prospectivo de 45 pacientes afectos de obstrucción nasal y desviación septal. Se exploran mediante RNMAA y EN, clasificando las desviaciones en cuadrantes anterosuperior y anteroinferior. Se analiza el grado de concordancia interobservador y la validez de la prueba diagnóstica. Resultados: Se obtiene una sensibilidad y especificidad del 74,6% y 60,5% respectivamente, comparando globalmente la RNMAA con la EN. Conclusión: La disminución del flujo en fase espiratoria se correlaciona con las obstrucciones inferiores objetivadas en la EN. En el estrecho vestíbulo fosal, esta correlación no es predictiva (AU)

Objective: Nasal permeability is related to functional and anatomical parameters, which are objectified by active anterior rhinomanometry (AARNM). The study aims to compare alterations visualized through Nasal Endoscopy (NE) with nasal flow parameters in AARNM. Material and methods: We carried out a prospective observational study of 45 patients suffering from nasal obstruction and septal deviation. They were explored through AARNM and NE, and the deviations were classified into anterosuperior and anteroinferior quadrants. The degree of agreement between observers and the validity of the diagnostic test was then analyzed. Results: A sensitivity of 74.6% and a specificity of 60.5% were obtained comparing AARNM and EN globally. Conclusion: A reduced flow of the expiratory phase is correlated to inferior obstructions observed through NE. In the narrow nasal vestibule this correlation is not predictive (AU)