Periodic emission of droplets from an oscillating electrified meniscus of a low-viscosity, highly conductive liquid.

The generation of identical droplets of controllable size in the micrometer range is a problem of much interest owing to the numerous technological applications of such droplets. This work reports an investigation of the regime of periodic emission of droplets from an electrified oscillating meniscus of a liquid of low viscosity and high electrical conductivity attached to the end of a capillary tube, which may be used to produce droplets more than ten times smaller than the diameter of the tube. To attain this periodic microdripping regime, termed axial spray mode II by Juraschek and Röllgen [R. Juraschek and F. W. Röllgen, Int. J. Mass Spectrom. 177, 1 (1998)], liquid is continuously supplied through the tube at a given constant flow rate, while a dc voltage is applied between the tube and a nearby counter electrode. The resulting electric field induces a stress at the surface of the liquid that stretches the meniscus until, in certain ranges of voltage and flow rate, it develops a ligament that eventually detaches, forming a single droplet, in a process that repeats itself periodically. While it is being stretched, the ligament develops a conical tip that emits ultrafine droplets, but the total mass emitted is practically contained in the main droplet. In the parametrical domain studied, we find that the process depends on two main dimensionless parameters, the flow rate nondimensionalized with the diameter of the tube and the capillary time, q, and the electric Bond number B(E), which is a nondimensional measure of the square of the applied voltage. The meniscus oscillation frequency made nondimensional with the capillary time, f, is of order unity for very small flow rates and tends to decrease as the inverse of the square root of q for larger values of this parameter. The product of the meniscus mean volume times the oscillation frequency is nearly constant. The characteristic length and width of the liquid ligament immediately before its detachment approximately scale as powers of the flow rate and depend only weakly on the applied voltage. The diameter of the main droplets nondimensionalized with the diameter of the tube satisfies d(d)≈(6/π)(1/3)(q/f)(1/3), from mass conservation, while the electric charge of these droplets is about 1/4 of the Rayleigh charge. At the minimum flow rate compatible with the periodic regimen, the dimensionless diameter of the droplets is smaller than one-tenth, which presents a way to use electrohydrodynamic atomization to generate droplets of highly conducting liquids in the micron-size range, in marked contrast with the cone-jet electrospray whose typical droplet size is in the nanometric regime for these liquids. In contrast with other microdripping regimes where the mass is emitted upon the periodic formation of a narrow capillary jet, the present regime gives one single droplet per oscillation, except for the almost massless fine aerosol emitted in the form of an electrospray.

[Prolonged convulsions treated with buccal midazolam in a setting of mentally retarded patients with refractory epilepsy]. / Tratamiento de las convulsiones prolongadas con midazolam intrabucal en una población de pacientes con discapacidad grave y epilepsia rebelde.

INTRODUCTION: Convulsive status epilepticus is a common major complication of epilepsy that results in high morbidity and mortality. Early treatment of prolonged seizures with rectal diazepam has been the method of choice in order to avoid this complication. However, several randomized trials in recent years suggest that buccal midazolam is as effective and safe as rectal diazepam. This study aims to seek further confirmation of the efficacy and safety of buccal midazolam in daily clinical practice. METHOD: Ten out of 73 adult epileptic patients who were residents in a center for people with severe encephalopathy were included. We recorded all seizures over a one-year period. Prolonged seizures, defined as a seizure lasting one minute or longer, were treated by placing buccal midazolam 5 mg (1 ml) between the lower lip and the gum. We administered a second dose of midazolam when the seizure lasted more than two minutes and a third dose of midazolam, or a combination of rectal diazepam 5 mg together with midazolam, as a rescue therapy when the seizure lasted for more than 3 minutes. Vital constants were monitored. RESULTS: We treated 52 prolonged seizures in 10 patients enrolled in the study. The treatment was effective with a single dose within two minutes in 80.7% of seizures. No cardiorespiratory complications were detected and no patients presented a convulsive status epilepticus. CONCLUSION: Buccal midazolam is effective and safe in the treatment of prolonged seizures and has the advantage of being a convenient and socially acceptable administration form.

Tratamiento de las convulsions prolongadas con midazolam intrabucal en una población de pacientes con discapacidad grave y epilepsia rebelde / Prolonged convulsions treated with buccal midazolam in a setting of mentally retarded patients with refractory epilepsy

Introducción. El estatus epiléptico es la complicación de la epilepsia que comporta mayor morbilidad y mortabilidad. El tratamiento precoz de las crisis prolongadas con diazepam rectal ha sido la manera habitual de evitar dicha complicación; sin embargo, en los últimos años diversos ensayos sugieren que la eficacia y seguridad del midazolam intrabucal es equivalente a la del diazepam rectal. El objetivo de este trabajo es ratificar la eficacia y seguridad del midazolam administrado por vía intrabucal en la práctica médica diaria. Método. En el estudio se incluyeron 10 pacientes adultos de los 73 epilépticos internos en un centro para pacientes con encefalopatías graves. Se registraron las crisis comiciales durante un período de 1 año. Se consideró como crisis prolongada aquella cuya duración era igual o superior a 1 min, administrándose midazolam 5 mg (1 ml) por vía intrabucal, aplicado entre el labio inferior y la encía. Se repitió una segunda dosis de midazolam cuando la crisis no cedió al cabo de 1 min. Se utilizó una tercera dosis de midazolam o la combinación midazolam 5 mg más diazepam rectal 5 mg como medicación de rescate cuando la crisis duró más de 3 min. Se registraron las constantes vitales. Resultados. Se trataron 52 convulsiones prolongadas en un total de 10 pacientes. La respuesta efectiva se obtuvo con una sola dosis de midazolam 5 mg en menos de 2 min en un 80,7% de los pacientes. No se detectó ninguna complicación cardiorrespiratoria y ningún paciente presentó estatus epiléptico. Conclusión. El midazolam intrabucal es efectivo y seguro en el control de las crisis prolongadas ofreciendo ventajas al ser una vía cómoda y socialmente aceptable (AU)

Introduction: Convulsive status epilepticus is a common major complication of epilepsy that results in high morbidity and mortality. Early treatment of prolonged seizures with rectal diazepam has been the method of choice in order to avoid this complication. However, several randomized trials in recent years suggest that buccal midazolam is as effective and safe as rectal diazepam. This study aims to seek further confirmation of the efficacy and safety of buccal midazolam in daily clinical practice. Method: Ten out of 73 adult epileptic patients who were residents in a center for people with severe encephalopathy were included. We recorded all seizures over a one-year period. Prolonged seizures, defined as a seizure lasting one minute or longer, were treated by placing buccal midazolam 5 mg (1 ml) between the lower lip and the gum. We administered a second dose of midazolam when the seizure lasted more than two minutes and a third dose of midazolam, or a combination of rectal diazepam 5 mg together with midazolam, as a rescue therapy when the seizure lasted for more than 3 minutes. Vital constants were monitored. RESULTS: We treated 52 prolonged seizures in 10 patients enrolled in the study. The treatment was effective with a single dose within two minutes in 80.7% of seizures. No cardiorespiratory complications were detected and no patients presented a convulsive status epilepticus. Conclusion: Buccal midazolam is effective and safe in the treatment of prolonged seizures and has the advantage of being a convenient and socially acceptable administration form (AU)

Esofagitis candidiásica en un paciente no inmunodeprimido / Candidiasic esophagitis in a non-immunodepressant patient

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