Results 191 to 200 of about 226,100 (242)
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Biological Reviews, 2008
AbstractThe flagellosperm of insects, although following a general ground plan, exhibit considerable variation in morphology and ultrastructure across taxa, consistent with a history of rapid and divergent evolution. Sperm competition, which occurs when sperm of two or more males compete for the fertilization of a female’s ova, has been recognized as a
Michael, Werner, Leigh W, Simmons
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AbstractThe flagellosperm of insects, although following a general ground plan, exhibit considerable variation in morphology and ultrastructure across taxa, consistent with a history of rapid and divergent evolution. Sperm competition, which occurs when sperm of two or more males compete for the fertilization of a female’s ova, has been recognized as a
Michael, Werner, Leigh W, Simmons
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Hyperactivated Motility in Sperm
Reproduction in Domestic Animals, 2003ContentsHyperactivation is a movement pattern seen in sperm at the site and time of fertilization in mammals. It may be critical to the success of fertilization, because it enhances the ability of sperm to detach from the wall of the oviduct, to move around in the labyrinthine lumen of the oviduct, to penetrate mucous substances and, finally, to ...
S S, Suarez, H-C, Ho
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Andrologia, 2009
To provide an alternative to presently available subjective ways of measuring sperm motility which often yield inconsistent data, we devised a method for determining sperm motile efficiency with it one can express objectively the amount of active sperm movement.
N, Ishii, S, Mitsukawa, M, Shirai
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To provide an alternative to presently available subjective ways of measuring sperm motility which often yield inconsistent data, we devised a method for determining sperm motile efficiency with it one can express objectively the amount of active sperm movement.
N, Ishii, S, Mitsukawa, M, Shirai
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Sperm motility in the presence of boundaries
Bulletin of Mathematical Biology, 1995The fluid dynamics of sperm motility near both rigid and elastic walls is studied using the immersed boundary method. Simulations of both single and interacting organisms are presented. In particular, we find that nearby organisms originally undulating with a 90 degree phase shift may adjust their relative swimming velocities and phase-lock ...
Fauci, Lisa J., McDonald, Amy
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Fertility and Sterility, 1983
Six different doses of caffeine were used to study its effect on human spermatozoal motility. The recently developed method for assessment of sperm motility by videomicrography was used to determine the percentage of sperm motility, swimming speed (velocity), percentage of progressive sperm, and progressive swimming speed.
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Six different doses of caffeine were used to study its effect on human spermatozoal motility. The recently developed method for assessment of sperm motility by videomicrography was used to determine the percentage of sperm motility, swimming speed (velocity), percentage of progressive sperm, and progressive swimming speed.
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Hyperactivated Motility in Sperm
Journal of Andrology, 1996The functions of hyperactivation may fit together to create the following scenario. Sperm that enter the oviduct bind to the mucosal epithelium. Near the time of ovulation, hyperactivation helps them to detach from the epithelium, escape mucosal pockets, and move through oviductal mucus.
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Sperm Motility, Velocity and Migration
British Journal of Urology, 1990Summary— Four different methods for evaluating sperm motility were analysed for experimental error: subjective assessment of a wet film preparation, sperm velocity measured by time‐lapse photography, sperm velocity measured by computer analysis and sperm migration across a nucleopore membrane.
D F, Badenoch +5 more
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The influence of prostaglandins on sperm motility
Prostaglandins, 1981Prostaglandin E2 and F2 alpha were measured in ejaculates from 10 fertile and 55 infertile men. Prostaglandin F2 alpha was negatively correlated with motility (r = 0.77; p less than 0.01) in normal men. In patients with disturbed fertility, prostaglandin F2 alpha was always higher than in the controls, while prostaglandin E2 was elevated only in ...
W, Schlegel +3 more
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Urogenital infection and sperm motility
Andrologia, 2003Male accessory sex gland infections are considered as potential hazards to male fertility. Various pathophysiological concepts have evolved from experimental and clinical studies that begin to explain the effects of bacteria and immunological events on the function of spermatozoa and sperm motility in particular. Besides direct influences of pathogenic
T, Diemer +4 more
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Sperm Motility in the Rat Epididymis
Fertility and Sterility, 1974The development of sperm motility was studied in rats with ligated caput epididymidis to determine whether intrinsic or extrinsic factors were involved. Most sperm moved in circular patterns; sperm from the ligated caput showed more motility after 7 to 10 days retention but none showed motion of the mature progressive type.
M H, Burgos, E S, Tovar
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