2:30 - 12:50 Fatema Zahra Rashid, PostDoc, Physics of Living Systems, VU Amsterdam
Title: TAV2b Peptide Derivatives Underwind and Stabilize Double- Stranded RNA upon Binding
Abstract: Double-stranded RNA (dsRNA) has become an essential tool to understand biological processes with promising therapeutic implications. However, its usage is often limited due to poor cellular uptake and instability in biological settings. Peptidic dsRNA binders, inspired by natural RNA-binding proteins, have emerged as promising tools to address these limitations. However, it remains unclear how these peptides recognize RNA and impact its mechanical properties. Here we employed single-molecule magnetic tweezers to investigate TAV2b-derived peptidic dsRNA binders. We showed that these peptides underwind dsRNA upon binding and stabilize the resulting dsRNA conformation. Additionally, the wild-type peptide increases the dsRNA contour length while significantly lowering the persistence length. In contrast, a high-affinity homodimeric derivative condenses the dsRNA tether at forces below 1 pN.
Furthermore, real-time experiments performed to understand the binding mechanism of TAV2b-derived peptides showed that the wild-type derivative is in dynamic association with dsRNA, whereas the homodimeric version forms a stable complex with dsRNA. Based on these findings, we propose a two-step equilibrium model where the RNA fluctuates between double-stranded and melted conformations, followed by peptide binding, which results in plectonemes. Our approach can inform the design of more potent and effective dsRNA binders for therapeutic and diagnostic applications.
12:50 -13:45 Paul Jansen from ASML Research, Veldhoven
Title: Plasma Interactions in EUV Lithography Machines
Abstract: EUV scanners operate in a low‑pressure hydrogen environment in which each exposure pulse generates a short‑lived EUV‑induced plasma. While this plasma helps mitigate carbon contamination, it simultaneously drives a range of surface, chemical, and charging phenomena that influence material durability and particulate contamination (defectivity).
In this colloquium, I will examine how EUV‑induced hydrogen plasmas form and evolve, how they interact with materials, and how they affect particulate charging and release. I will show that this plasma acts as a double‑edged sword: on one hand its properties are deliberately exploited to keep optical surfaces clean and to manage charge accumulation, while on the other hand it introduces mechanisms that complicate reliable high‑volume manufacturing.
The aim is to provide a physics‑based perspective on how transient EUV‑driven plasmas shape scanner performance through their impact on materials and reticles, and why understanding these interactions – both in laboratory setups and in situ - is essential for robust next‑generation chip production.