学术活动
20
2023-07
[ 大师讲坛 ]
【大师讲坛】第197期:面向低碳未来的燃烧化学研究
Since global climate and health issues are becoming more urgent, many countries have made pledges towards carbon reduction and net zero within the next decades. Defossilization is one major aspect in such scenarios. The increasing introduction of renewable power goes along with a different focus and new opportunities for combustion science and applications. Alternative fuels and fuel blends as well as novel combustion and aftertreatment strategies aim to reduce the carbon footprint and local emissions. From a chemical viewpoint, such measures introduce exciting research questions regarding in-depth information on the combustion process, including detailed, fundamentally founded reaction mechanisms and physico-chemical combustion models of predictive character. Progress relies increasingly on valuable combinations of experiments, theory, simulation, and data strategies. The talk will highlight some recent examples of combustion chemistry research within this general discussion. Powerful in-situ diagnostic methods are applied to probe reactive systems in laboratory configurations. Results from prototypical fuels will be shown also to provide some guidance for further theoretical studies and model development. Such selected examples can serve as food for thought about chances and challenges in the transition towards carbon-reduced processes.
Katharina Kohse-Höinghaus
中国科学院外籍院士
05
2023-07
[ 大师讲坛 ]
【大师讲坛】第194期:Nanoimprint and Nano-Enabled Artificial Intelligence for Instant Mobile Self-Test (iMOST)
Nanotechnology is undoubtedly one of the most important technologies in the 21st century, impacting a very broad range of scientific research and industries, from semiconductor ICs, and data storage, nanophotonics, batteries, displays, light emitting diodes, optical communication, virtual reality, biotechnology, medicine, security features, to name just a few. However, the full potential of nanotechnology cannot be utilized, unless we have a nanomanufacturing technology that can manufacture nanostructures with high throughput and low cost. Of all existing technologies for manufacturing well-defined nanostructures, nanoimprint clearly is one of the most promising ones. Nanoimprint has a unique combination of attributes, including the highest resolution (0.3 nm!), the smallest pitch (<10 nm), large-area (e.g. wall-paper size), high-throughput and low cost, that are unmatchable by other existing methods. As a result, nanoimprint has emerged as one of the most important manufacturing technologies in the 21st century, and is rapidly evolving into a multi-billion-dollar industry. As the inventor of nanoimprint, the author will present his view overview on the status and future of nanoimprint in research and industrialization. Furthermore, the author will discuss another groundbreaking technology innovation called iMOST™ (instant Mobile Self-Test) – a new platform for healthcare test, that he has invented and developed*. iMOST is designed to offer instant mobile personal self-medical-diagnostic testing that is accurate, reliable, simple to use, affordable to everyone, and can be used anywhere and anytime. iMOST achieved its goals by outside-the-box thinking and a new paradigm, that is fundamentally different from the traditional and that successfully removes several key roadblocks in testing outside a lab. The new paradigm has the following unique features: (i) “Fault-Tolerant” (ii) “One Device for All” and (iii) low-cost, portable and scalable. The new paradigm is uniquely achieved by using nanotechnology, advance imaging, Nano-Enabled Artificial intelligence/Machine-learning (NEAM) and new bio/chemical processes into diagnostic testing. iMOST is poised to replace traditional, expensive, time-consuming lab test, significantly impacting future telemedicine. * The iMOST work was performed at Essenlix Corp
Stephen Y. Chou
美国工程院院士
03
2023-07
[ 大师讲坛 ]
【大师讲坛】第193期:Visualization of Co-translational Protein Folding
Protein folding can begin co-translationally. Due to the difference in timescale between folding and synthesis, co-translational folding is thought to occur at equilibrium for fast folding domains. Thus, the folding kinetics of stalled ribosome-bound nascent chains should match the folding of nascent chains in real time. We test this assumption by comparing the folding of a ribosome-bound, multi-domain calcium-binding protein stalled at different points in translation with the nascent chain as is it being synthesized in real-time, via optical tweezers. In vitro, a misfolded state of the protein occurs readily, and on stalled ribosomes, the misfolded state still forms rapidly (1.5 s). Surprisingly, during active translation, this state is only attained after a long delay (~ 60 s), indicating that, unexpectedly, the growing polypeptide is not equilibrated with its ensemble of accessible conformations. Slow equilibration on the ribosome can delay premature folding until adequate sequence is available and/or allow time for chaperone binding, thus promoting productive folding. On the other hand, interactions between the nascent polypeptide and the ribosome exit tunnel represent one mode of regulating synthesis rates, which, in turn, are thought to affect protein folding. The SecM protein arrests its own translation as part of a feedback mechanism, and release of arrest has been proposed to occur by mechanical force at the translocon. This is the so-called translocon mechanical hypothesis. Using optical tweezers, I demonstrate that arrest of SecM-stalled ribosomes can indeed be rescued by force alone. Moreover, I will show that the force needed to release stalling can be generated in vivo by a nascent chain folding near the ribosome tunnel exit. I formulate a kinetic model describing how a protein can regulate its own synthesis by the force generated during folding, tuning ribosome activity to structure acquisition by a nascent polypeptide.
Carlos Bustamante
美国国家科学院院士,美国艺术与科学院院士