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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 28 (1991), S. 292-296 
    ISSN: 1040-452X
    Keywords: Zonae pellucidae ; Trypsin inhibitor ; β-Mercaptoethanol ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The present study confirms that zonae pellucidae of rat oocytes became resistant to chymotrypsin digestion (zona hardening) after undergoing in vitro maturation (IVM) in a serum-free medium. However, zona hardening and did not occur when empty zonae without oocytes were cultured in the same IVM conditions, suggesting that oocyte-derived factor(s) is responsible for zona hardening in oocytes matured in the serum-free medium. Zona hardening occurred primarily after dictyate oocytes were cultured for 6-8 hours in the IVM medium without serum. Zona hardening could be prevented or alleviated if oocytes were cultured in the IVM medium containing bovine foetal calf serum, a soybean trypsin inhibitor, or β-mercaptoethanol, and in vitro fertilization rates for such oocytes were normal. Possible mechanisms of the phenomenon of zona hardening in oocytes matured in serum-free conditions are discussed in relation to its possible relevance to the cortical reaction and the physiological block to polyspermy.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 32 (1992), S. 28-32 
    ISSN: 1040-452X
    Keywords: tPA ; Cortical granule reaction ; Sperm penetration ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The resumption of meiosis results in synthesis of tissue-type plasminogen activator (tPA) in the rat and mouse oocytes (Haurte et al., Cell 43:551-558, 1985). The present study demonstrates that freshly ovulated rat oocytes released their tPA into the surrounding medium upon in vitro activation by sperm penetration or treatment with a calcium ionophore. The presence of a neutralizing monoclonal anti-tPA antibody during in vitro activation by the calcium ionophore inhibited the activation-induced zona hardening and also preserved the ability of the oocyte to be penetrated by sperm subsequent to activation. Rat oocytes undergo zona hardening during in vitro maturation in the absence of serum, presumably as a result of spontaneous cortical granule release, based on findings in mice and hamsters. In the present study, the anti-tPA antibody prevented the zona hardening and enhanced partition by spermatozoa of rat oocytes that were matured in vitro without serum. Collectively, the observations reported here suggest a possible role of tPA released during the cortical granule reaction in the zona reaction, which contributes to the block to polyspermy.
    Additional Material: 1 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 23 (1989), S. 267-277 
    ISSN: 0148-7280
    Keywords: gonadotropins ; oocytes ; maturation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The present study examined the effects of gonadotropins and ovarian steroids during in vitro meiotic maturation of rat oocytes on their ability to undergo in vitro fertilization. Fully grown oocytes were isolated from antral follicles of immature rats and cultured as oocyte-cumulus cell complexes (OCC) under conditions in which completion of meiotic maturation occurs spontaneously. They were then exposed to spermatozoa under conditions in which oocytes matured in vivo exhibit high fertilization rates. Compared with oocytes from pregnant mare's serum gonadotropin (PMSG) or follicle-stimulating hormone (FSH)-treated rats, a simiiar proportion of the oocytes (〉80%) from untreated rats underwent germinal vesicle breakdown, but such oocytes had a lower rate of fertilization (70% vs. 20%). The presence of FSH during in vitro maturation restored the fertilization rate for oocytes from untreated rats, while a cytochrome P450 inhibitor, aminoglutethimide phosphate abolished this beneficial effect of FSH. The addition of progesterone during the in vitro maturation period duplicated the beneficial effect of FSH on fertilization rate of oocytes from untreated rats; oestradiol-17β was less effective in this regard, and 5α-dihydrotestosterone was ineffective. These findings indicate that FSH and progesterone, although having no apparent effect on nuclear maturation of the oocyte, play an important role during oocyte maturation in enabling normal fertilization to occur.
    Additional Material: 4 Ill.
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  • 4
    Publication Date: 2019-07-19
    Description: A case study and monthly statistical analysis using sounder data assimilation to improve the Alaska regional weather forecast model are presented. Weather forecast in Alaska faces challenges as well as opportunities. Alaska has a large land with multiple types of topography and coastal area. Weather forecast models must be finely tuned in order to accurately predict weather in Alaska. Being in the high-latitudes provides Alaska greater coverage of polar orbiting satellites for integration into forecasting models than the lower 48. Forecasting marine low stratus clouds is critical to the Alaska aviation and oil industry and is the current focus of the case study. NASA AIRS/CrIS sounder profiles data are used to do data assimilation for the Alaska regional weather forecast model to improve Arctic marine stratus clouds forecast. Choosing physical options for the WRF model is discussed. Preprocess of AIRS/CrIS sounder data for data assimilation is described. Local observation data, satellite data, and global data assimilation data are used to verify and/or evaluate the forecast results by the MET tools Model Evaluation Tools (MET).
    Keywords: Meteorology and Climatology
    Type: M13-3023 , 2014 American Meteorological Society (AMS) Annual Meeting; Feb 02, 2014 - Feb 06, 2014; Atlanta, GA; United States
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  • 5
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Meteorology and Climatology
    Type: MSFC-E-DAA-TN22680 , 2015 Alaska Weather Symposium; May 11, 2015 - May 12, 2015; Anchorage, AK; United States
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  • 6
    Publication Date: 2019-07-13
    Description: Data assimilation has been demonstrated very useful in improving both global and regional numerical weather prediction. Alaska has very coarser surface observation sites. On the other hand, it gets much more satellite overpass than lower 48 states. How to utilize satellite data to improve numerical prediction is one of hot topics among weather forecast community in Alaska. The Geographic Information Network of Alaska (GINA) at University of Alaska is conducting study on satellite data assimilation for WRF model. AIRS/CRIS sounder profile data are used to assimilate the initial condition for the customized regional WRF model (GINA-WRF model). Normalized standard deviation, RMSE, and correlation statistic analysis methods are applied to analyze one case of 48 hours forecasts and one month of 24-hour forecasts in order to evaluate the improvement of regional numerical model from Data assimilation. The final goal of the research is to provide improved real-time short-time forecast for Alaska regions.
    Keywords: Meteorology and Climatology
    Type: M14-3263 , Symposium on the Joint Center for Satellite Data Assimilation; Feb 06, 2014; Atlanta, GA; United States|2014 American Meteorological Society (AMS) Annual Meeting; Feb 02, 2014 - Feb 06, 2014; Atlanta, GA; United States
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  • 7
    Publication Date: 2019-07-12
    Description: Covers the whole breadth of mineral dust research, from a scientific perspective Presents interdisciplinary work including results from field campaigns, satellite observations, laboratory studies, computer modelling and theoretical studies Explores the role of dust as a player and recorder of environmental change This volume presents state-of-the-art research about mineral dust, including results from field campaigns, satellite observations, laboratory studies, computer modelling and theoretical studies. Dust research is a new, dynamic and fast-growing area of science and due to its multiple roles in the Earth system, dust has become a fascinating topic for many scientific disciplines. Aspects of dust research covered in this book reach from timescales of minutes (as with dust devils, cloud processes, and radiation) to millennia (as with loess formation and oceanic sediments), making dust both a player and recorder of environmental change. The book is structured in four main parts that explore characteristics of dust, the global dust cycle, impacts of dust on the Earth system, and dust as a climate indicator. The chapters in these parts provide a comprehensive, detailed overview of this highly interdisciplinary subject. The contributions presented here cover dust from source to sink and describe all the processes dust particles undergo while travelling through the atmosphere. Chapters explore how dust is lifted and transported, how it affects radiation, clouds, regional circulations, precipitation and chemical processes in the atmosphere, and how it deteriorates air quality. The book explores how dust is removed from the atmosphere by gravitational settling, turbulence or precipitation, how iron contained in dust fertilizes terrestrial and marine ecosystems, and about the role that dust plays in human health. We learn how dust is observed, simulated using computer models and forecast. The book also details the role of dust deposits for climate reconstructions. Scientific observations and results are presented, along with numerous illustrations. This work has an interdisciplinary appeal and will engage scholars in geology, geography, chemistry, meteorology and physics, amongst others with an interest in the Earth system and environmental change.
    Keywords: Meteorology and Climatology
    Type: GSFC-E-DAA-TN7780 , Mineral Dust - A Key Player in the Earth System
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