Kinetics Studies on Isomerization and Unimolecular Decay Processes of the Criegee Intermediate, Methacrolein (MACR) Oxide

Alkenes are one of the major components of hydrocarbons in our atmosphere. One of the most common alkenes in our atmosphere is isoprene (2-methyl – 1,3 – butadiene). Currently, it is known that isoprene ozonolysis can lead to the production of Criegee intermediates CH2OO, methacrolein (MACR) oxide, and methyl vinyl ketone (MVK) oxide. In part, we were interested in studying one specific Criegee intermediate, MACR oxide. The competition between the isomerization reactions and the unimolecular reactions became the focus of our study. Rate constants for the relevant reactions were calculated by implementing RRKM theory and using Master Equation modeling to create a scheme for the system. The overall results show that the most favorable reaction of MACR oxide is the isomerization between the cis and trans conformations. Because the transition states between these conformations are relatively low compared to the other transition states in the reaction, the conversions are observed to happen much faster than the others. The next fastest reaction that takes place is the unimolecular decay reactions to the dioxiranes and the dioxole. The decay reactions involved barriers that were higher than the cis⇌trans conversion but still lower than the barrier between the anti⇌syn conversion. With dioxole being our most stable state, our main interest was if different conformers of MACR oxide will decay to this structure in an atmospherically relevant time frame. It was found that substantial fraction (80%) of MACR oxide cannot decompose to dioxole in the relevant time frame as the barrier for the conversion between anti and syn is too high. We saw that there was almost no anti⇌syn conversion in any of our calculations

Neural Transcription Factors: from Embryos to Neural Stem Cells

The early steps of neural development in the vertebrate embryo are regulated by sets of transcription factors that control the induction of proliferative, pluripotent neural precursors, the expansion of neural plate stem cells, and their transition to differentiating neural progenitors. These early events are critical for producing a pool of multipotent cells capable of giving rise to the multitude of neurons and glia that form the central nervous system. In this review we summarize findings from gain- and loss-of-function studies in embryos that detail the gene regulatory network responsible for these early events. We discuss whether this information is likely to be similar in mammalian embryonic and induced pluripotent stem cells that are cultured according to protocols designed to produce neurons. The similarities and differences between the embryo and stem cells may provide important guidance to stem cell protocols designed to create immature neural cells for therapeutic uses

Creative integration of design thinking and strategic thinking in a design education framework

With rapid globalization, designers are increasingly required to use creative integration of strategic thinking and design thinking to deal with complexity and uncertainty in an era of constant transformation. This study reviews the current status of design education to address the key question of how strategic thinking and design thinking can be enhanced creatively in undergraduate design students’ education in South Korea. Furthermore, it investigates the key drivers for and barriers to the enhancement of strategic thinking and design thinking; seeks insights from successful design education programs; and gathers perspectives about strategic thinking and design thinking from design students, educators, and strategists. By using qualitative (in-depth interviews) and quantitative (a questionnaire) research methods, the study offers significant insights: (i) design undergraduates’ short-sighted mind-set should be reshaped, (ii) additional practical, multicultural, and interdisciplinary applications of strategic thinking are needed to bridge the gap between theoretical and practical classes, and (iii) consistent stimulation is required to internalize strategic thinking and design thinking