Nagao Y.,Utsunomiya University |
Nagao Y.,Tokyo University of Agriculture and Technology |
Ohta Y.,Utsunomiya University |
Ohta Y.,Science Service Inc. |
And 2 more authors.
Zygote | Year: 2010
In this study, we investigated the effects of methyl-β-cyclodextrin (MBCD) on in vitro fertilization and the subsequent development of bovine oocytes. Bovine oocytes matured in serum-free medium were inseminated with frozen-thawed sperm pre-incubated in protein-free modified Brackett and Oliphant medium (BO) containing various concentrations of MBCD for various periods. MBCD decreased the frequency of live sperm, however enhanced the capacitation and acrosome reaction of the live sperm. Pre-incubation of sperm with 0.5, 1.0 and 1.5 mM MBCD for 2 and 4 h increased the frequency of normal fertilization. Embryos derived from oocytes fertilized with spermatozoa pre-incubated with MBCD developed normally to the blastocyst stage and term. There were individual differences and similar tendencies in four different sires in terms of the effects of MBCD upon fertilization. These results indicate that the pre-incubation of bovine sperm with MBCD affects viability and capacitation status of the sperm and promotes fertilization in vitro. Embryos derived from oocytes fertilized with sperm pre-incubated with MBCD developed normally to the blastocyst stage and term. © 2010 Cambridge University Press.
Tsutsumi S.,Japan Aerospace Exploration Agency |
Ishii T.,Japan Aerospace Exploration Agency |
Ui K.,Japan Aerospace Exploration Agency |
Tokudome S.,Japan Aerospace Exploration Agency |
Wada K.,Science Service Inc.
Journal of Spacecraft and Rockets | Year: 2015
Subscale model tests and a numerical investigation are performed to predict and attenuate the acoustic level of the Epsilon launch vehicle at liftoff. Requirements for the subscale model test to predict a full-scale acoustic environment are investigated, and then the scale size of the model test is set at 1/42. The launch pads employed herein are designed to attenuate reflection of the Mach wave radiated from the free jet and the acoustic wave due to the jet's impinging on the flame deflector. When comparing the acoustic result taken at the fairing location with that at three different altitudes, 9De, 14De, and 22De, whereDe represents the nozzle exit diameter, the acoustic level observed at 14De is the highest and exceeds the design requirement at all frequencies. It is revealed from the numerical analysis that the reflection of Mach waves radiating from the free jet within the flame path is the dominant acoustic source.Afront cover is attached to the vertical flame path to shield the Mach wave radiation, and 3 dBattenuation in the overall sound pressure level is achieved. The design methods and the knowledge obtained in this study are valid for the design of the launch pad to attenuate liftoff acoustics. Copyright © 2014 by the American Institute of Aeronautics and Astronautics, Inc.
Society For Science & The Public and Science Service Inc. | Date: 1993-02-02
Society For Science & The Public and Science Service Inc. | Date: 1990-12-04
Society For Science & The Public and Science Service Inc. | Date: 1981-05-26