Optimizing Electrical Activation of Porcine Oocytes by Adjusting Pre‐ and Post‐Activation Mannitol Exposure Times     

D Kwon  IM Saadeldin  SJ Kim  SJ Park  JT Kang  HJ Park  JH Moon  OJ Koo  G Jang  BC Lee 《Reproduction in domestic animals》2014,49(6):995-999

Modifying electrical activation conditions have been used to improve in vitro embryo production and development in pigs. However, there is insufficient information about correlations of porcine embryo development with oocyte pre‐ and post‐activation conditions. The purpose of this study was to compare the developmental rates of porcine oocytes subjected to different mannitol exposure times, either pre‐ or post‐electrical activation, and to elucidate the reason for the optimal mannitol exposure time. Mannitol exposure times around activation were adjusted as 0, 1, 2 or 3 min. Blastocyst development were checked on day 7. Exposure of oocytes to mannitol for 1 or 2 min before electrical activation produced significantly higher blastocyst rates than exposure for 0 or 3 min. There was no significant difference in blastocyst rates when activated oocytes were exposed to mannitol for 0, 1, 2 or 3 min after electrical activation. While exposure of oocytes to mannitol for 1 min pre‐ and 3 min post‐activation showed significantly higher blastocyst development than 0 min pre‐ and 0 min post‐activation. It also showed higher maintenance of normal oocyte morphology than exposure for 0 min pre‐ and 0 min post‐activation. In conclusion, exposure of oocytes to mannitol for 1 min pre‐ and 3 min post‐activation seems to be optimal for producing higher in vitro blastocyst development of porcine parthenogenetic embryos. The higher blastocyst development is correlated with higher maintenance of normal morphology in oocytes exposed to mannitol for 1 min pre‐ and 3 min post‐activation.  相似文献   

Spectral Properties of Near-Earth Asteroids: Evidence for Sources of Ordinary Chondrite Meteorites     

RP Binzel  SJ Bus  TH Burbine  JM Sunshine 《Science (New York, N.Y.)》1996,273(5277):946-948

Although ordinary chondrite (OC) meteorites dominate observed falls, the identification of near-Earth and main-belt asteroid sources has remained elusive. Telescopic measurements of 35 near-Earth asteroids ( approximately3 kilometers in diameter) revealed six that have visible wavelength spectra similar to laboratory spectra of OC meteorites. Near-Earth asteroids were found to have spectral properties that span the range between the previously separated domains of OC meteorites and the most common (S class) asteroids, suggesting a link. This range of spectral properties could arise through a diversity of mineralogies and regolith particle sizes, as well as through a time-dependent surface weathering process.  相似文献   

Incidence of laminitis and survey of dietary and management practices in pleasure horses and ponies in south‐eastern Australia          下载免费PDF全文

SJ Potter  NJ Bamford  PA Harris  SR Bailey 《Australian veterinary journal》2017,95(10):370-374

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Thermographic selection of effective catalysts from an encoded polymer-bound library     

SJ Taylor  JP Morken 《Science (New York, N.Y.)》1998,280(5361):267-270

A general method is introduced for the rapid and simultaneous evaluation of each member of large encoded catalyst libraries for the ability to catalyze a reaction in solution. The procedure was used to select active catalysts from a library of potential polymer-bound multifunctional catalysts. From approximately 7000 beads screened (3150 distinct catalysts), 23 beads were selected for catalysis of an acylation reaction. Kinetic experiments indicate that the most strongly selected beads are also the most efficient catalysts.  相似文献   

Photonic channels for quantum communication     

van Enk SJ  JI Cirac  P Zoller 《Science (New York, N.Y.)》1998,279(5348):205-208

A general photonic channel for quantum communication is defined. By means of local quantum computing with a few auxiliary atoms, this channel can be reduced to one with effectively less noise. A scheme based on quantum interference is proposed that iteratively improves the fidelity of distant entangled particles.  相似文献