Q: Share something about yourself.
Hi, I’m Hugues Lambert from the Institute of Materials Discovery, University College of London. I have been working at A*STAR's Institute of High Performance Computing for two and a half years (2018-2021) under the A*STAR Research Attachment Programme.
I’ve spent a significant time looking at what happens to molecules when they get trapped in a confined space. I study cucurbiturils - the inside of large, barrel-like molecules that can encapsulate other small molecules. This confinement is able to modulate the way molecules react, break down and even interact with light, chiefly through supramolecular, non-covalent interactions. These are simulating effects we often see in enzymes,
powerful biological catalysts, whose selectivity and efficiency have yet to be rivalled by synthetic analogs. As cucurbiturils are of manageable size, we studied them using sophisticated computational techniques that were impractical for larger systems such as enzymes. We were, therefore, able to reach a deep, sometimes quantitative, insight into the phenomena taking place in the cucurbituril cavity and support the understanding of larger systems. Given the opportunity to use exclusive computational tools, I could study many different systems and quickly try out new ideas without waiting for reagents compared to my fellow colleagues who worked in the labs.
Q: Tell us about what you do at IHPC?
I have been working on several projects and was fortunate to see some successful completions and had the opportunity to publish a research paper. One incident to highlight was when my supervisor, Professor Zhang Yong-Wei (Deputy Executive Director, Research, IHPC), suggested applying our research capabilities to industries relevant to Singapore’s economy. Coincidentally I chanced upon an article about Shell setting up a xylene refining plant in Jurong. A critical reaction for xylene comes in three different configurations: Ortho, Meta and Para, and converting the first two configurations to the para one is the most valuable.
Amazingly, computational investigations revealed that some cucurbituril species were potentially able to assist these “isomerisation” reactions. We obtained the results using biased molecular dynamics where we use mathematical tricks to encourage the system to visit high energy regions that would otherwise be out of reach due to fundamental time and computational power constraints. This would have been impossible to perform on larger systems but we have proven to characterise this supramolecular complex with significant flexibility properly. We have also managed to publish these results and are eager to see experimental catalysis specialists trying it out. I liked this project a lot as it allowed me to sharpen my skill set and connect theoretical/computational results with experimental data. We were fortunate that xylene isomerisation is a thoroughly researched reaction even though, to my knowledge, we were the first to suggest that an organic macrocycle could catalyse it.
In the world of simulations in general, a common challenge is interpreting the results generated from the software we use. Setting up and compiling the programs could be tricky when they could be written by small groups and might not be well tested for all distributions or unstable. Once the program is up and running, it would usually return results for the problems you submitted. It can be problematic, for example, when one uses a theoretical model that is not suited for the system studied, the results might look fine even though they might be completely meaningless.
To me, one of the most challenging aspects of the job - “how far can I trust what the computer is telling me?”. This means cross-checking with the relevant literature and experimental results as often as possible and in general to be very critical of raw numbers returned by a program.
Q: Describe a typical work week.
Life has been good here for me in Singapore. In the morning, I would usually grab a set of ‘kopi and kaya toast’ on my way to the office. After replying to emails, I would unpack the finished computations or fix the ones that crashed. During the afternoon, I try to break new ground, read papers, start a few exploratory computations or launch a production run. I would also try to exercise twice a week by jogging along the canals between Buona Vista and Clementi or practicing Brazilian Jiu-Jitsu. On Friday nights, I often met up with friends in Holland Village for a few cold drinks. On weekends, I make the most of what Singapore has to offer leisure-wise and visit restaurants, museums, outdoor natural spaces or even go to the beach. Visiting famous food courts is also one of my enjoyable weekend pastime. The Jurong Bird Park, Singapore Zoo and the S.E.A aquarium (where they host giant manta rays) particularly impressed me.
Q: How has this internship benefits you?
I have benefited a lot from working with my supervisors - Professor Zhang and Professor Tung-Chun Lee (University College of London). Their extensive experience had given me great clarity whenever I am in doubt. I appreciate, in particular, their ability to articulate scientific results and turn them into a compelling story. As communication is such an important part of science, their advice has been invaluable. IHPC has also organised several seminars with researchers and collaborators, which helped boost my development and widen my professional connections.