6 research outputs found
Selective trapping of DNA using glass microcapillaries
We show experimentally that a cheap glass microcapillary can accumulate
{\lambda}-phage DNA at its tip and deliver the DNA into the capillary using a
combination of electro-osmotic flow, pressure-driven flow, and electrophoresis.
We develop an efficient simulation model for this phenomenon based on the
electrokinetic equations and the finite-element method. Using our model, we
explore the large parameter space of the trapping mechanism by varying the salt
concentration, the capillary surface charge, the applied voltage, the pressure
difference, and the mobility of the analyte molecules. Our simulation results
show that this system can be tuned to capture a wide range of analyte
molecules, such as DNA or proteins, based on their electrophoretic mobility.
Our method for separation and pre-concentration of analytes has implications
for the development of low-cost lab-on-a-chip devices.Comment: 9 pages, 4 figure
Application of two different nasal CPAP levels for the treatment of respiratory distress syndrome in preterm infants-"The OPTTIMMAL-Trial"-Optimizing PEEP To The IMMAture Lungs: study protocol of a randomized controlled trial.
BACKGROUND
Nasal continuous positive airway pressure (CPAP) applies positive end-expiratory pressure (PEEP) and has been shown to reduce the need for intubation and invasive mechanical ventilation in very low birth weight infants with respiratory distress syndrome. However, CPAP failure rates of 50% are reported in large randomized controlled trials. A possible explanation for these failure rates is the application of insufficient low levels of PEEP during nasal CPAP treatment to maintain adequate functional residual capacity shortly after birth. The optimum PEEP level to treat symptoms of respiratory distress in very low birth weight infants has not been assessed in clinical studies. The aim of the study is to compare two different PEEP levels during nasal CPAP treatment in preterm infants.
METHODS
In this randomized multicenter trial, 216 preterm infants born at 26â+â0-29â+â6 gestational weeks will be allocated to receive a higher (6-8 cmH2O) or a lower (3-5 cmH2O) PEEP during neonatal resuscitation and the first 120âh of life. The PEEP level within each group will be titrated throughout the intervention based on the FiO2 (fraction of inspired oxygen concentration) requirements to keep oxygenation within the target range. The primary outcome is defined as the need for intubation and mechanical ventilation for >â1âh or being not ventilated but reaching one of the two pre-defined CPAP failure criteria (FiO2 >â0.5 for >â1âh or pCO2 â„â70âmmHg in two consecutive blood gas analyses at least 2âh apart).
DISCUSSION
Based on available data from the literature, the optimum level of PEEP that most effectively treats respiratory distress syndrome in preterm infants is unknown, since the majority of large clinical trials applied a wide range of PEEP levels (4-8 cmH2O). The rationale for our study hypothesis is that the early application of a higher PEEP level will more effectively counteract the collapsing properties of the immature and surfactant-deficient lungs and that the level of inspired oxygen may serve as a surrogate marker to guide PEEP titration. Finding the optimum noninvasive continuous distending pressure during early nasal CPAP is required to improve CPAP efficacy and as a consequence to reduce the exposure to ventilator-induced lung injury and the incidence of chronic lung disease in this vulnerable population of very preterm infants.
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Efectos de las rodadas de tractores en la escorrentĂa y erosiĂłn de suelos en laderas cultivadas con viñedos
16 pĂĄginas, 6 figuras, 3 tablas.Peer reviewe