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aster

 [as´ter]
a structure occurring in dividing cells, composed of microtubules radiating from a centrosome. The two asters are the poles of the spindle apparatus.
 Asters separating in prophase of mitosis. From Dorland's, 2000.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

as·tro·sphere

(as'trō-sfēr),
A set of radiating microtubules extending outward from the cytocentrum and centrosphere of a dividing cell.
[G. astron, star, + sphaira, ball]
Farlex Partner Medical Dictionary © Farlex 2012

aster

(ăs′tər)
n.
Biology A star-shaped structure formed in the cytoplasm of an animal cell during mitosis, having raylike microtubules that surround the centrosome.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

as·tro·sphere

(as'trō-sfēr)
A set of radiating microtubules extending outward from the cytocentrum and centrosphere of a dividing cell.
Synonym(s): aster, attraction sphere.
[G. astron, star, + sphaira, ball]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
Asterclick for a larger image
Fig. 54 Aster . Generalized form.

aster

a group of blind-ending SPINDLE MICROTUBULES radiating out from the CENTRIOLES of dividing cells in lower plants and all animals. The aster function is uncertain, but does not seem to be concerned with spindle formation.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
References in periodicals archive ?
The autumn darkness fell, and most of the passengers wandered below after we had cleared the bridge by 13 feet and left the Lower Harbor astern. I remained on the port boat deck to watch the pilot being taken off at Sandy Hook in a swift little boat whose curling wake, illuminated by the lights of the ship, gleamed on the black water as she nudged against the sheer black hull running with a white foam, and he descended to the boat by ladder while we continued to build toward cruising speed into the open sea.
Ghanimifard has previously mentioned that Iran may come to the astern countries to get the required investment in this field.
Hmay's ship, a reconditioned World War I four-stack destroyer, opened fire on a German plane whose torpedo went astern after the ship made a hard turn, its guns blazing at the airplane.
So, to purloin a nautical expression: it's full astern for 2008!
After the firing runs, the aircraft were to proceed to a point 10 miles astern of the ship to rendezvous for a formation flyover.
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Leaving the green and going down out through the gatehouse, you turn back and look at the grey zinc roofs of what at first evokes a strange notion of the Grand Fleet with two squadrons of Dreadnoughts sailing in line astern to make a pincer movement on the Kriegsmarine.
I'd swear that the added weight of the batteries astern actually imbues the IMA with better balance.
But soon, performing a visual diminuendo, they drift well astern, a distant nebula of glittering pinpoints at the planet's indistinguishable edge.
From my position directly astern of the Arizona, I had a clear view of her when she got hit and blew up.