Time filter

Source Type

Columbia, MI, United States

Green M.P.,University of Missouri | Green M.P.,University of Melbourne | Harvey A.J.,University of Melbourne | Spate L.D.,University of Missouri | And 6 more authors.
Molecular Reproduction and Development | Year: 2016

The preimplantation bovine embryo displays sexual dimorphism in glucose sensitivity and interferon-tau (IFNT) secretion that are negated by inhibition of the pentose phosphate pathway, suggesting that the association between glucose metabolism and IFNT likely underpins the selective loss of female embryos. The aim of this study was to determine if altered glucose metabolism, through glucose supplementation and/or uncoupling oxidative phosphorylation with 2,4-dinitrophenol (DNP), affected embryo development. Bovine blastocyst development, sex, and IFNT production were examined in embryos cultured in the presence or absence of glucose (0, 1.5, 4mM) with or without exposure to DNP (0, 10, 100μM) between Days 5 and 8 post-fertilization. The absence or presence of high (4mM) glucose reduced blastocyst development and favored the development of male embryos (P<0.001). DNP at 10μM had no effect, whereas 100μM had a negative impact on blastocyst development. Notably, in the presence or even absence of glucose, supplementation with 10μM DNP further skewed the sex ratio toward males (P<0.05). Sexually dimorphic IFNT production was maintained in these conditions, although total production was reduced in the presence of high glucose and DNP, irrespective of embryo sex. These data suggest that the pentose phosphate pathway can modulate embryonic sex ratio and development. Therefore, bovine embryo culture should be undertaken in a low glucose (<2.5mM) medium to minimize potential embryonic stress, as higher concentrations have sexually dimorphic effects on development and an embryo's ability to signal to the maternal reproductive tract. © 2016 Wiley Periodicals, Inc.

Goldschmidt B.S.,240ristopher nd Life Science Center | Rudy A.M.,240ristopher nd Life Science Center | Nowak C.A.,240ristopher nd Life Science Center | Macoubrie D.P.,240ristopher nd Life Science Center | And 2 more authors.
Optics and Laser Technology | Year: 2015

Thin films continue to show great promise for improving devices in optical applications, such as improved chemical sensors based on surface plasmon resonance devices (Gardon et al. (2008) [1] and Brolo et al. (2004) [2]). While ellipsometry and reflectometry are standard characterization techniques for determining thickness and refractive index of thin films, these techniques tend to require highly reflective or polished films and rely on empirical equations like the Cauchy, Briot, Hartmann, Conrady, and Sellmeier empirical dispersion equations. While these empirical equations may be accurate in some wavelength ranges and for non-conductive materials, the researcher must identify which equation is appropriate for the film being tested and wavelength range desired. To improve ease of testing, we have created a new technique, Optical Tunneling Photoacoustic Spectroscopy (OTPAS), that uses light-induced ultrasound to measure the amount of optical tunneling that has occurred with frustrated total internal reflection through a thin film. The OTPAS system allows a researcher to obtain thickness and refractive index estimates of transparent films without polishing or knowledge of empirical equations prior to the experiment. Scans of 200 nm thick MgF2 films were used to compare ellipsometry with the OTPAS technique. An example of our results shows mean refractive index and thickness estimates of 1.395±0.011 and 220±19 nm versus 1.392±0.002 and 195.2±1.8 nm at 532 nm for ellipsometry, which suggests a general agreement between the two techniques. We present OTPAS to be used for the determination of optical properties of transparent single layer films in cases where empirical equations cannot be used or in cases of low optical reflection. © 2015 Elsevier Ltd.All rights reserved.

Discover hidden collaborations