About Me

Thanks for stopping by my page. As you could probably tell already, my name is Dávid Deritei, you can call me Dávid. I’m a fresh Ph.D. graduate from the Department of Network and Data Science, Central European University, Budapest. I am a physicist by training and my main focus is the understanding the fundamental driving forces of complex systems ranging from the protein-protein interactions of the biological cell to organization of societies.

I have a wide variety of professional and personal interests, the role of this home page is to project some of it to anyone who might be interested.

My Scientific Path

I am a physicist by training but besides my interest in the classical physics subjects I found an early interest in networks during my undergraduate years, at the Babeş-Bolyai University in Romania. My bachelor’s thesis under the leadership of Dr. Zsolt Lázár was a study of random Boolean networks, where we linked some of the characteristics of the emergent dynamical attractors to structural features, such as the degree distribution of the network. I started my masters in computational physics and I was very fortunate to have been offered a research assistant position in our department in a project led by Dr. Mária Ercsey Ravasz. During this period we published a novel network community detection method that used graph-Voronoi diagrams [1]. This project also became the basis of my master’s thesis. In this period I also met Dr. Erzsébet Ravasz Regan, whom I joined in her project of developing a new Boolean dynamic model for the cell cycle. I had the fortune to visit her twice at the Beth Israel Deaconess Medical Center, Harvard Medical School. Our paper, published in 2016, proposed a new cell cycle model and also discussed a theoretical view on how small decision-making modules (switches) coordinate to create higher level emergent dynamic behavior, such as the cell cycle. We called this view dynamical modularity [2].

After finishing my masters I worked one more year in Dr. Ercsey-Ravasz’s project and then moved to Budapest, where I started my Ph.D. in Network and Data Science at the Central European University. After passing the first year coursework and comprehensive exam I chose a research topic that somewhat diverged from my previous experience. I started working with Bayesian networks in trying to understand the statistical nature of cognition, more specifically vision. This project did not work out, but I came away with an understanding and appreciation of Bayesian networks and statistics, which I still find fascinating. I returned to Boolean networks and biological modeling after a wonderful opportunity offered by Prof. Réka Albert. Using the wide range of tools developed by her group we started a deep dive into the cell cycle model we published earlier with Dr. Ravasz Regan, to better understand the mechanistic details of how the intriguing dynamic properties of the model emerge from the structure of the regulatory network. I spent a very productive year in Prof. Albert’s lab at Penn State. During this year, we found that there is a small circuit, embedded in the cell cycle regulatory network, which is responsible for driving the cell cycle from checkpoint to checkpoint. If we remove all checkpoints this circuit will exhibit a strikingly robust oscillation. We discovered that the robustness of the oscillation can be explained in the framework of conditionally stabilizing network motifs that form a system-wide negative feedback loop [3]. I also collaborated with Dr. Regan in publishing a significantly larger and more comprehensive Boolean network model of the cell cycle (as compared to the one published in 2016), which besides many things explained PI3K-induced aberrant cell cycle progression connected with various cancer types [4].

In February 2020 I submitted my doctoral thesis entitled Dynamical Hierarchy in Biological Regulatory Networks: Applications to the Cell Cycle, supervised Prof. Réka Albert from Penn State University and by Prof. János Kertész from the Central European University. The thesis is available for download under this link. Besides my fascination with biological dynamic systems I have a range of other professional interests (e.g. life quality index based on walkability in cities [5]), as well as industry experience, most notably working with the Swiss drug pricing and market access startup Akceso Advisors A.G. over a period of eight years. I’ve also had several short term projects with the consulting company founded by Prof. Albert-László Barabási, Maven7.