نتایج جستجو برای: sperm penetration distance
تعداد نتایج: 308753 فیلتر نتایج به سال:
We present an eecient algorithm for simulation of non-penetrating exible bodies with nonlinear elasticity. We use nite element methods to discretize the continuum model of non-rigid objects and the fast marching level set method to precompute a distance eld for each un-deformed body. As the objects deform, the distance elds are deformed accordingly to estimate penetration depth, allowing enforc...
Genetic selection procedures applied to improve broiler performance may negatively impact the subsequent reproductive efficiency of breeders, particularly in males. Identification of traits that reliably indicate individual male fertility would facilitate selection for reproduction. We hypothesized that physical traits, such as comb area, relative testicular weight, and testicular weight asymme...
We present an e cient algorithm for simulation of non-penetrating exible bodies with nonlinear elasticity. We use nite element methods to discretize the continuum model of non-rigid objects and the fast marching level set method to precompute a distance eld for each undeformed body. As the objects deform, the distance elds are deformed accordingly to estimate penetration depth, allowing enforce...
This review compiles all the research done on gametes and fertilization in the rock shrimp, R. typus, and describes the sequence of events from the first gamete interaction to zygote formation and the first cleavage of the embryo, with light, fluorescence confocal and electron microscopes. Early studies showed that sperm from the vas deferens have a tack-shape with a "needle-like process" or ri...
Human Papillomaviruses (HPVs) are a diverse group of viruses that infect the skin and mucosal tissues of humans. A high-risk subgroup of HPVs is associated with virtually all cases of cervical cancer [1]-[3]. High-risk HPVs are transmitted sexually; however, the exact mechanisms by which sexual contact promotes virus infection remain uncertain. To study this question we asked whether capsids of...
Sperm carbohydrate binding activity is involved in gamete recognition. We identified a human sperm protein extracted under reducing conditions, and with a molecular mass of 65 kDa on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), and which binds D-mannose coupled to albumin (DMA) in presence of cations and a neutral pH. Epifluorescence microscopy showed that fluorescein-...
statement of problem: it has been established that successful root canal treatment depends on the quality of obturation. deeper penetration of spreaders can improve the apical seal and the quality of the obturation. purpose: the aim of this study was to compare the initial penetration depth of spreaders during lateral condensation of 0.04 and 0.02 tapered gutta-percha master cones. materials an...
Mammalian sperm must hyperactivate in order to fertilize oocytes. Hyperactivation is characterized by highly asymmetrical flagellar bending. It serves to move sperm out of the oviductal reservoir and to penetrate viscoelastic fluids, such as the cumulus matrix. It is absolutely required for sperm penetration of the oocyte zona pellucida. In order for sperm to hyperactivate, cytoplasmic Ca(2+) l...
The effects of the experimental fragmentation of native eucalypt forest on the beetle community were tested, in a controlled, replicated, long-term experiment. Included in our design were three fragment sizes, fragment edge and interior sites, and sites in the surrounding exotic pine plantation matrix. We followed 325 species through 28 sampling periods over seven years, including two years pre...
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