Postpartum dairy cows (n=35) were used to determine the effects of feeding propylene glycol (PG) on metabolic variables related to ovarian function and on oocyte developmental competence. Starting on Day 7 postpartum, each animal received an oral dose (500 ml) of either PG or water once daily. Blood samples were collected on Days 5, 15, 25 and 35 pp to measure insulin, non-esterified fatty acids (NEFAs), beta-hydroxybutyrate (BHB) and glucose concentrations. Oocytes were recovered by ultrasound guided follicular aspiration starting on approximately Day 30 postpartum and submitted to in vitro fertilization. Ovarian follicular activity was examined daily by ultrasonography from Day 7 until ovulation or Days 35-40 postpartum. Animals receiving PG had elevated insulin concentrations over the subsequent 90 min following dosing (P<0.05) compared to control animals. Glucose concentrations followed a similar pattern. Irrespective of treatment, concentrations of NEFA declined significantly from Days 15 to 35 postpartum. Administration of PG resulted in a decrease in NEFA (P<0.001) and BHB (P<0.001) over the subsequent 90 min compared to control animals. Treatment with PG had no effect on follicular dynamics, mean days to emergence of the first cohort of follicles postpartum, or days to dominance and duration of dominance for any follicular wave recorded postpartum. There was also no difference in mean days to first ovulation or in size of the preovulatory follicle between treatments. Oocyte quality as measured by blastocyst development after IVF was not affected by treatment. These results suggest that administration of PG has the ability to positively alter the systemic concentrations of a number of metabolic variables which have been related to fertility. However, we did not observe an effect of PG treatment on follicular dynamics or the length of the postpartum interval. An effect on oocyte developmental competence remains to be proven.
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http://dx.doi.org/10.1016/j.theriogenology.2007.12.001 | DOI Listing |
J Am Chem Soc
December 2024
State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
The carbonylative polymerization of olefin yields aliphatic polyketones, which are used as engineering plastics in the market due to their excellent mechanical strength, chemical resistance, and surface and barrier properties. However, the usage of precious palladium catalysts has restricted their extensive application as commodity materials. Herein, we present a series of phosphine-sulfonate Ni catalysts with a wide spectrum of electronic and steric substituents on the phosphorus moiety for the carbonylative polymerization of ethylene.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
October 2024
School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China.
Nonoxidative dehydrogenation of propane is useful for the high selectivity to propylene but is suffering from the heavy coke deposition on the catalyst surface. Herein, we present a proof-of-concept application of a hole-hydrogen (H) couple on a metallic cobalt surface to decrease the deactivation rate. The coupled H atoms on the Cobalt (Co) surface, partially resulting from propane dehydrogenation, enabled the desorption of propylene to avoid deep hydrogenolysis and coke deposition and realize selective and durable propylene production, while conventional Co metal-based catalysts do not generate propylene.
View Article and Find Full Text PDFHeliyon
September 2024
Xiamen Key Laboratory for Feed Quality Testing and Safety Evaluation, Fisheries College, Jimei University, Xiamen City, Fujian Province, 361021, PR China.
Angew Chem Int Ed Engl
September 2024
School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, 30332, Atlanta, GA, USA.
Asymmetric carbon molecular sieve (CMS) hollow fiber membranes with tunable micro- and macro-structural morphologies for energy efficient propylene-propane separation are reported here. A sub-glass transition temperature (sub-Tg) thermal oxidative crosslinking strategy enables simultaneous optimization of the intrinsic molecular sieving properties while also reducing the thickness of the CMS "skin" derived from the 6FDA : BPDA/DAM polyimide precursors. Such synergistic tuning of CMS microstructure and macroscopic morphology of CMS hollow fibers enables significantly increased propylene permeance (reaching 186.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2024
Department of Physics, School of Physical Science and Engineering, Beijing Jiaotong University, Beijing, 100044, P. R. China.
Simultaneously enhancing selectivity and stability on supported propane dehydrogenation (PDH) catalysts remains a formidable challenge. Here, we report a combined static and dynamic strategy to address these issues synergistically. Firstly, we demonstrate a feasible sol-gel method for preparing atomically-dispersed Bi-decorated metal nanoparticle catalysts (MBi/AlO, M=Fe, Co, Ni, and Zn).
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