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791.
Dr. Alexandra D. Easley Alison Mangano Prof. Dr. Brett P. Fors 《Angewandte Chemie (International ed. in English)》2023,62(20):e202218062
Polyurethanes (PUs) are a class of materials usually synthesized from isocyanates, diols, and water. Water is essential for producing carbon dioxide (CO2) which is used for the self-blowing of the foams. Due to safety concerns with the production of isocyanates, alternative chemistries have been evaluated and cyclic carbonate systems have shown great promise. In a recent advancement by Bourguignon, Grignard, and Detrembleur, a cyclic carbonate and diamine system is capable of generating CO2 for self-blowing through hydrolysis of the carbonate-based monomer. The authors demonstrate that with a simple variation of the diamine monomer a wide range of physical and thermo-mechanical properties were achievable. This work represents a significant step towards safer and more environmentally friendly PUs. 相似文献
792.
Bryony Davidson Norah Spears Alison Murray Alistair Elfick 《Journal of Raman spectroscopy : JRS》2012,43(1):24-31
Despite an exponential uptake in recent years of assisted reproductive techniques, such as in vitro fertilisation, much is still not fully understood about the biochemical modifications that take place during the development and maturation of the egg and embryo. As such, in order to improve the efficiency of these techniques, furthering our understanding of the processes that underpin oocyte and embryo development is necessary. Raman spectroscopic mapping as a technique enables the investigation of biochemical variation within intact cells without the need for labelling. Here, Raman maps of fixed immature and mature oocytes along with early stage embryos were collected using 785 nm excitation and a step size of 2 µm. The results were analysed using both univariate and multivariate techniques. It was found that significant macromolecular accumulation took place during oocyte maturation, while a decrease in total lipid content consistent with the formation of new cellular membranes is observed upon embryo cleavage. Furthermore, an observed asymmetrical localisation of macromolecules in the mature oocyte may indicate the existence of cytoplasmic polarisation, a phenomenon that has been observed in the eggs of lower organisms. As such, these results indicate that Raman spectroscopic mapping may present an alternative analytical tool for investigating the biochemistry of egg and embryo development. In particular, these results indicate that temporal Raman analysis may help to reveal the existence of cytoplasmic polarisation in the murine egg. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献