Comparison of diagnostic methods for hemodynamic treatment in unborn and pre-term infants using the measurement of vena cava, lactate, and clinical criteria

Introduction: There is no single criterion available to assess the hemodynamic state of new-born infants and preterm infants and the different variables in the group of newborns, such as gestational age, birth weight, and periods of birth. Methods: This is an epidemiological, cross-sectional, descriptive observational study with two patient cohorts. Newborn-to-term and preterm neonates assisted at the Neonatal Unit of the Pablo Arturo Suarez Hospital participated during the months between November 2019 to January 2020. Results: Ultrasound measurement of the vena cava (FVC) flow is useful for the management treatment of hemodynamically unstable neonatal patients. The sample was made up of 110 newborns treated in the Pablo Arturo Suarez Hospital's neonatology service from November 2019 to January 2020. Quito, Pichincha, Ecuador. The variables low birth weight and moder-ate prematurity have a statistically significant value for inotropic use. The other variables do not present statistically significant values. Heart rate, urinary output, mean blood pressure, lactic acid, capillary filling, upper vena cava flow, and lower vena cava flow had statistically significant values. FVCI and FVCS comparisons with heart rate, urinary output, mean blood pressure, lactic acid, and capillary filling had statistically significant values, except for capil-lary filling> 3 sec in FCVI. Multivariate analysis of categorical main components (CATPCA) was used to characterize the hemodynamic state and inotropic state, which were significant in the bivariate analysis. Dimension, one of the two-dimensional graphs, discriminates the use or not of inotropics and the categories of hemodynamic parameters TAM <35 mmHg, lactic acid, capillary filling, FVCI, and FVCS. Dimension II discriminates between the categories of urinary expenditure and HR. Conclusion: In term and preterm infants with low weight and adequate birth weight with hemodynamic instability in general, who were evaluated with ultrasonography to measure the flow of the vena cava, the agreement between the clinical criteria and the ultrasound assessment of the flow was 0.4 cm/sec in both methods. This situation means that the measurement of venous cava flows by echo sonography is useful for assessing neonatal patients' hemodynamic status.

Capillary Filling Dynamics of Electromagnetohydrodynamic Flow of Non-Newtonian Fluids

In this work, we aim to develop a mathematical model for capillary filling dynamics of electromagnetohydrodynamic flow of non-Newtonian fluids. An axially applied electric field and a transverse magnetic field are considered to elucidate the electromagnetohydrodynamic transport through the microcapillary. Assuming a non-Newtonian power-law obeying fluids, we analyze the transient evolution of the electromagnetohydrodynamic capillary positions by considering the magnitude of the total force balance via finite volume-based numerical formalism. We have highlighted the various rheological regimes in the horizontal capillary through a scaling analysis. For the Newtonian fluids, corresponding inviscid linear Washburn regime is also analyzed and compared with the power-law obeying fluids. Furthermore, we have also derived closed-form analytical expressions for the electromagnetohydrodynamic velocity, pressure gradient, and transient evolution of the capillary positions by using couple stress parameter model to characterize the fluid rheological behaviors. We perform a comparison test of the coupled stress parameter model with the results from the literature for a similar set of fluid rheological parameters. The comparison results are found to be in good agreement.

Long-term hydrophilization of polydimethylsiloxane (PDMS) for capillary filling microfluidic chips

We present a simple and facile method for long-term preservation of hydrophilicity of oxygen plasma-hydrophilized poly (dimethylsiloxane) (PDMS) by cold storage. We show that storage under temperature of − 80 °C can maintain superhydrophilicity of plasma-exposed PDMS for at least 100 days. Storage at − 15 °C and at 22 °C room temperature (RT) is shown to exhibit, respectively, about half and full recovery of the original hydrophobicity after 100 days in storage. Furthermore, we investigated the implications of the cold storage for microfluidic applications, the capillary filling rate and the ability of the flow to bypass geometrical obstacles in a microfluidic channel. It is shown that the preservation of capillary filling properties of microchannels is in close agreement with the contact angle (CA) measurements and that the colder the storage temperature, the better the capillary filling capability of the channels is preserved. We ascribe the significantly reduced recovery rate to reduced thermally activated relaxation phenomena such as diminished diffusion of low molecular weight species (LMW) in the polymer matrix at colder temperatures. This is supported by ATR-FTIR measurements of the OH vibration band over time for samples stored at different temperatures.