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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 501 for “"sperm"”.
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Marine invertebrate sperm: assessment of sperm quality using computer-aided sperm analysis
… midae (Gastropoda) were investigated. The sperm morphology and base-line data were gathered concerning the sperm concentration, motility and sperm kinematic parameters using computer-aided-sperm analysis (CASA). Sperm morphology and sperm motility play an important role in determining sperm …
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Chemotaxis of Sperm Cells
Sperm cells are guided to the egg by chemoattractants in many species. Sperm cells are propelled in a liquid by the regular beat of their flagellum. In the presence of a concentration gradient of a chemoattractant, they can steer upwards the concentration gradient, a process called chemotaxis. Eggs …
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The effects of sperm dose, semen quality, and retrograde sperm blockage on accessory sperm number and embryo quality in the artificially inseminated bovine
… was designed to: 1. Determine the effects of sperm dose and retrograde sperm blockage on mean number accessory sperm/ova. 2. Evaluate the relationship between mean number accessory sperm/ova and fertilization status/embryo quality. 3. Determine if mean number accessory sperm/ova or embryo …
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Analysis of Human Sperm Chromatin Integrity
… present study evaluated the integrity of human spermatozoal nuclear material in the two condensation stages of chromatin and chromosomes. Original semen samples (ORI) and their swim-up fractions (SW, selected for motility) from men of known (donors) and unknown (patients) fertility were …
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Novel Modulators of Human Sperm Motility
… and is most commonly characterised by asthenozoospermia (reduced sperm motility). Incredibly, there is currently no known treatment for this condition, and the only option is Artificial Reproduction Technology (ART) which is expensive and invasive. The development of a novel treatment would …
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Sperm release from the oviduct reservoir
Sperm undergo capacitation while traveling through the female reproductive tract, a process including several biochemical and physiological events before fertilization. Also prior to fertilization, sperm bind to the epithelial cells of the oviduct isthmus to form a sperm reservoir. This sperm …
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Hyperactivation of human sperm by 4-Aminopyridine: key role for mobilisation of stored Ca2+ in the sperm neck
Within the female reproductive tract mammalian sperm gradually develop hyperactivated motility, triggered by increased flagellar Ca2+ resulting in deep flagellar bends. Two sources of Ca2+ may contribute to the regulation of hyperactivation. Ca2+ influx at the plasma membrane is crucial and the …
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Characterization of Phosphatidylserine Expression in Bovine Sperm
… expression of phosphatidylserine (PS) on bovine sperm and investigate what factors may impact it, as previous research demonstrated that phosphatidylserine (PS) plays a role in murine fertilization. Despite conventionally being an apoptotic marker, it is present on viable and …
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High-throughput sperm cryopreservation of aquatic species
… disciplines for application of high-throughput sperm cryopreservation to aquatic species. The blue catfish Ictalurus furcatus was selected for research due to its role in production of hybrid catfish with eggs from channel catfish Ictalurus punctatus. A high-throughput cryopreservation pathway …
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Acrosomal molecules exposure during human sperm capacitation
At ejaculation sperm cells cannot fertilize. They need to undergo a series of molecular modifications to achieve competency. Surprisingly,molecular markers for identifying sperm populations competent to fertilize are not robust. However, recently an intra - acrosomal protein exposed at the …
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Factors Affecting Sperm Production by Dairy Bulls
Made available in DSpace on 2014-12-05T23:07:51Z (GMT). No. of bitstreams: 1 0019800.pdf: 4718592 bytes, checksum: d9b80e724deaac7a4e197a17684359b4 (MD5) Previous issue date: 1956
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The Evolution of Fitness After Prolonged Sperm Storage
… exposure will ultimately be detrimental due to sperm-depletion and infertility. Females are therefore expected to balance mating opportunities and sperm storage capacity to maximize lifetime reproductive success. I introduced extended mating deprivation as a selective pressure to experimentally …
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Towards A Unified Model Of Sperm Chromatin Structure
<p>Sperm possess several layers of information that are delivered to the oocyte alongside the paternal DNA. Examples of potential sperm borne molecular cues of probable use to the embryo include RNAs and local and global chromatin structure. To identify candidate sperm RNAs that likely reach the …
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Aneuploidy and DNA fragmentation in morphologically abnormal sperm
Introduction: Intracytoplasmic sperm injection (ICSI) has been a successful assisted reproductive technique for men with severe male-factor infertility. However, ICSI requires the subjective selection of normal looking sperm, which does not preclude the transmission of genetically abnormal sperm. …
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Organization of Human Sperm Chromosomes During Pronuclei Formation
… have demonstrated that chromosomes of human spermatozoa have well-defined spatial organization that includes preferred intranuclear positioning. The hypothesis of this dissertation is that sperm chromosome architecture participates in controlled transformation and activation of the paternal …
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Negative biomarkers of sperm quality and male fertility
… light microscopy provides information about sperm motility and basic morphology but has a limited ability to predict reproductive performance in an assisted reproduction setting. In-depth analysis carried out quickly and with repeatable precision on a large number of sperm cells is important …
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Sperm utilization patterns in Gryllus integer (orthoptera: gryllidae
Sperm competition is the competition for fertilizations between ejaculates, within a female, following multiple mating. There are four sperm utilization or precedence patterns: first male precedence, where the first male to mate fertilizes most of the eggs laid by a female; last male precedence, …
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