BACKGROUND Vascular endothelial growth factor-A (VEGF-A) is intensively investigated in various medical fields. However, comparing VEGF-A measurements is difficult because sample acquisition and pre-analytic procedures differ between studies. We therefore investigated which variables act as confounders of VEGF-A measurements. METHODS Following a standardized protocol, blood was taken at three...

Plants transport water under negative pressure and this makes their xylem vulnerable to cavitation. Among plant organs, root xylem is often highly vulnerable to cavitation due to water stress. The use of centrifuge methods to study organs, such as roots, that have long vessels are hypothesized to produce erroneous estimates of cavitation resistance due to the presence of open vessels through me...

In this paper, a simple model for the prediction of centrifuge cone penetration tip resistance in sand is presented. The proposed method, which relates the tip resistance to the pressure to expand a spherical cavity, refines and simplifies Greeuw’s original equations. The method assumed the failure mode of a spherical cavity expansion pressure given as a function of shear stiffness, angle of fr...

A method is described for the large-scale purification of the Bacillus thuringiensis protein crystal by zonal gradient centrifugation. NaBr gradients are employed in a Beckman J21-B centrifuge equipped with a JCF-Z rotor.

The removal of bacterial populations from large volumes of liquid culture media may be accomplished readily using a centrifuge, but the usual efficient continuous-feed type of centrifuge is often large and expensive. In this laboratory, during the past 2 years, bacterial cells have been removed from liquid culture with considerable success, using a small, inexpensive, continuously fed centrifug...

Structural analysis of new devices to be used in centrifuge facilities can be a challenging task. Initial calculations, based on simple basic static principles, are usually used. However, as devices placed in a geotechnical centrifuge are often complex structures, advanced analysis methods to assess their performance under enhanced acceleration fields are desirable. This paper presents the anal...

Vulnerability to cavitation curves describe the decrease in xylem hydraulic conductivity as xylem pressure declines. Several techniques for constructing vulnerability curves use centrifugal force to induce negative xylem pressure in stem or root segments. Centrifuge vulnerability curves constructed for long-vesselled species have been hypothesised to overestimate xylem vulnerability to cavitati...

In this study, the effect of rarefied region in rotor centrifuge was investigated. a centrifuge, feed inlet is positioned area. The continuum hypothesis not valid area; therefore, it desires to be analyzed by probabilistic methods like Direct Simulation Monte Carlo (DSMC). present Computational Fluid Dynamic (CFD) method used simulate area, and DSMC employed An implicit coupled density-based sc...

Vulnerability curves using the 'Cavitron' centrifuge rotor yield anomalous results when vessels extend from the end of the stem segment to the centre ('open-to-centre' vessels). Curves showing a decline in conductivity at modest xylem pressures ('r' shaped) have been attributed to this artefact. We determined whether the original centrifugal method with its different rotor is influenced by open...