Four catheters (Ash Split Cath, Tesio, Duo-Split, and Duo--Flow; Medcomp, Harleysville, PA, U.S.A.) were tested in a temperature-controlled in vitro setup filled with 50% aqueous glycerin solution to determine hydraulic resistance at different flow rates. All these catheters have side holes; hydraulic resistance was determined with these holes open and closed. Due to extra pressure losses near ...

The ferns comprise one of the most ancient tracheophytic plant lineages, and occupy habitats ranging from tundra to deserts and the equatorial tropics. Like their nearest relatives the conifers, modern ferns possess tracheid-based xylem but the structure-function relationships of fern xylem are poorly understood. Here, we sampled the fronds (megaphylls) of 16 species across the fern phylogeny, ...

The effects of acute changes in circulating blood volume on embryonic vascular hemodynamics were evaluated with the use of input impedance. We simultaneously measured dorsal aortic pressure with a servo-null system and flow velocity with a 20-MHz pulsed Doppler system in n = 90 stage 24 chick embryos. We withdrew or infused 1,3, or 5 microliters of blood via a second-order vitelline vein (n = 1...

We examine the validity of commonly used Hagen-Poiseuille model local resistance porous media using direct numerical simulations. provide theoretical arguments that highlight possible limitations this and formulate a new constitutive is based on circularity iso-pressure surfaces. compare performance both models three different three-dimensional artificial media. show improves root-mean-squared-...

The hydraulic resistance characterization manuscript chronicles the early development of the hollow-core fiberoptic microneedle device (FMD). The study determined that for straight tubing with an inner bore of 150 μm and a length greater than 50 mm long, Poiseuille’s Law was shown to be accurate within 12% of experimental data for the pressure range of 69-517 kPa. Comparison between different n...

−This paper proposes a method that can be used for the resistance estimation of a PWM (Pulse Width Modulation)-driven solenoid. By using estimated solenoid resistance, the PWM duty ratio was compensated to be proportional to the solenoid current. The proposed method was developed for use with EHB (Electro-Hydraulic Braking) systems, which are essential features of the regenerative braking syste...

This study had the purpose of documenting the hemodynamic correlates of effective arterial elastance (Ea; i.e., an accurate estimate of hydraulic load) in mitral stenosis (MS) patients. The main hypothesis tested was that Ea relates to the total vascular resistance (R)-to-pulse interval duration (T) ratio (R/T) in MS patients both before and after successful balloon mitral valvotomy (BMV). High...

Water availability has been considered one of the crucial drivers of species distribution. However, the increasing of temperatures and more frequent water shortages could overcome the ability of long-lived species to cope with rapidly changing conditions. Growth and survival of natural populations adapted to a given site, transferred and tested in other environments as part of provenance trials...