Abstract Objective Density gradient centrifugation (DGC) is commonly used for sperm preparation before assisted reproductive technology (ART) procedures. This technique separates superior motile spermatozoa with normal morphology from the total population. However, there still controversy as to effects of this separation on cell DNA integrity which a determining element in process fertilization...

In this paper, we describe a cultivation procedure in large-capacity fermentors (200 liters) and the purification of the Salmonella crude extracts by means of zonal centrifugation in a sucrose gradient. Briefly, the endotoxin has been extracted from salmonellae with hypertonic solutions. The crude endotoxin was shown to contain several antigens, mainly r(1), r(2), r(3), or heterologous antigen....

We demonstrate the use of centrifugation for efficient separation of colloidal gold nanorods from a mixture of nanorods and nanospheres. We elucidate the hydrodynamic behavior of nanoparticles of various shapes and illustrate that the shape-dependent drag causes particles to have shape-dependent sedimentation behavior. During centrifugation, nanoparticles undergo Brownian motion under an extern...