Integrated Calendar

Text-conditioned image editing has recently attracted considerable interest. However, most methods are currently either limited to specific editing types (e.g., object overlay, style transfer), or apply to synthetically generated images, or require multiple input images of a common object. In this paper we demonstrate, for the very first time, the ability to apply complex (e.g., non-rigid) text-guided semantic edits to a single real image. For example, we can change the posture and composition of one or multiple objects inside an image, while preserving its original characteristics. Our method can make a standing dog sit down or jump, cause a bird to spread its wings, etc. — each within its single high-resolution natural image provided by the user. Contrary to previous work, our proposed method requires only a single input image and a target text (the desired edit). It operates on real images, and does not require any additional inputs (such as image masks or additional views of the object). Our method, which we call "Imagic", leverages a pre-trained text-to-image diffusion model for this task. It produces a text embedding that aligns with both the input image and the target text, while fine-tuning the diffusion model to capture the image-specific appearance. We demonstrate the quality and versatility of our method on numerous inputs from various domains, showcasing a plethora of high quality complex semantic image edits, all within a single unified framework

Fundamental understanding of physiological processes that occur at biological membranes, such as membrane fusion, necessitates addressing not only the biochemical aspects, but also biophysical aspects such as membrane mechanical properties and membrane curvature. In this talk, I will show how we combine membrane model systems, micropipette aspiration, optical tweezers and confocal fluorescence microscopy to study membrane shaping and membrane fusion processes. I will describe a new tool we developed, where we form membrane bilayers supported on polystyrene microspheres which can be trapped and manipulated using optical tweezers. Using this approach, we demonstrate successful measurements of the interaction forces between the Spike protein of SARS CoV-2 and its human receptor, ACE2. We further use bead-supported membranes interacted with aspirated vesicles to reveal the inhibitory effect of membrane tension on hemifusion. I will also describe a particular case of membrane shaping during the formation of the newly discovered organelle termed migrasome. We show that tetraspanin proteins involved in migrasome formation strongly partition into curved membrane tethers, and we reveal a novel, two-step process of migrasome biogenesis.

Our starting point is the idea that specific regions in the protein evolve to
become flexible viscoelastic elements facilitating conformational changes
associated with function, especially allostery. Simple theories show how
these regions can emerge through evolution and indicate that they are
easily identified by amino acid rearrangement upon binding (i.e., shear
motion). Surprisingly, AlphaFold can also identify such regions by
computing the shear induced by a single or a few mutations. With these
methods, we have tested the concept of shear and its functional relevance
in a variety of proteins. I will present recent results from an experimental
study of the enzyme guanylate kinase linking shear, large scale motions,
and catalytic function. Altogether, the present findings paint a physical
picture of proteins as viscoelastic machines with sequence encoded
specifications, and we will discuss its general implications for
understanding proteins and designing new ones.

Fertilization is a complex multistep process that culminates with the formation of a zygote and the initiation of embryonic development. My main research interest is understanding the mechanisms underlying the final step of fertilization, sperm-egg fusion. The sperm-specific protein IZUMO1 anchors sperm by its binding with an egg-membrane receptor (JUNO). My results indicate that IZUMO1 has a second crucial role: allowing genetic exchange by inducing membrane fusion. More recently, I described a new phenomenon, whereby sperm can induce the fusion of somatic cells expressing ectopic JUNO, in a viral-like mechanism. This occurs under specific conditions, which make it a robust research and clinical tool. Altogether, this research will shed light on the climax of fertilization, with implications for infertility treatment and birth control.

Catalysts are essential in increasing reaction rates of chemical reactions. They have not only shaped our modern world but are also used by nature in many biochemical reactions. Understanding catalytic mechanisms and developing new catalysts holds promise to e.g. solve energy challenges of our society.
Before this background, I am developing new methodologies based on magnetic resonance to unravel processes in catalysis and work towards nano-materials in which nuclear spin states can be controlled
during reactions. Thereby, I am making use of the technique of parahydrogen induced polarization, which is an enhancement technology in NMR, boosting signals by four orders of magnitude. This approach uses parahydrogen, a spin isomer of normal hydrogen gas that interacts with a catalyst and undergoes a chemical reaction. During this process, the spin order of parahydrogen is converted into largely enhanced magnetic resonance signals and acts as a spy molecule for the catalytic process.
In recent years my group has pioneered the use of parahydrogen to study metalloenzymes and more in specific hydrogenases. Hydrogenases are considered nature's blueprint for efficient hydrogen activation catalysts. Although they represent an important class of enzymes, the catalytic mechanisms leading to hydrogen activation are not fully understood. My developed tools allowed for new insights that no other analytical technology could provide and thereby refined details of the catalytic mechanisms.
Additionally, my group has been researching the development of nano-catalysts that can allow for maintaining the para-hydrogen spin order on surfaces. This promises on one side to develop new enhancement strategies in particular to boost the signal of mobile protons that can e.g. exchange with proteins or small molecules leading to their further enhancements in solution. On the other side, a precise control of nuclear spin states during chemical reactions in solution can allow for the future production of
large quantities of spin-controlled chemicals such as para-water or formaldehyde in the para-state. These are chemicals found in e.g. interstellar clouds showing different ratios between ortho (triplet) and para (singlet) states as compared to earth and are thought to display different reactivities. Understanding the effect of nuclear spin states on reactions could lead to new application in chemical reactions and catalysis
in the future.