Bjørn Olav Hald

Bjørn Olav Hald


I am a postdoc at the Section of Renal and Vascular Research, Department of Biomedical Sciences, where I also obtained my PhD. In recent years, my work has primarily concerned 1) the regulation of flow in resistance arteries and arterioles of the microcirculation, and 2) the metabolic control of glycolytic oscillations in yeast cells. Primarily, my work consists of development and analysis of computational models of the biological systems, but I also do work in the ”wet” lab.

Primary fields of research

  • Microcirculation
  • Metabolism
  • Heterogeneity in biological systems

Current research

So-called "Conducted responses" facilitate long-range transfer of information between cells in the vascular walls. These responses probably have a major influence on flow regulation in the microcirculation, which in turn determines the peripheral blood pressure. Upon high blood pressure, many small arterioles become bigger in themselves, while their lumen become smaller. My research address the mechanisms behind those forms of regulation both experimentally and through computer modeling.

Yeast metabolism
A population of starved yeast cells can exhibit oscillations in their metabolism. Oscillations are complex behavior resulting from possibly numerous regulations, and synchronization of many oscillators is not a simple problem. However, synchronization is essential to many oscillatory physiological systems, e.g. circadian rhythms. The yeast system is a sufficiently simple and robust system to study how oscillations and especially how robust synchronization of oscillatores may occur in biological systems.

In all biological systems, the constituent cells are slightly different in terms of e.g. protein expression, size, and morphology. This diversity is rooted in external factors and/or genetic material, but the significance of this variability is not very well understood. On the other hand, it is well known that while no two tissues or organs are the same, the function and output of a tissue is (almost) always appropriate to the physiological needs. What physiological advantages/disadvantages the heterogeneity convey can be examined using the model systems above.

Computational tools
Modeling and simulation of large physiological systems requires control of many thousands of parameters and a proper dealing with computational load. Development of systems that handles large model system are needed to develop a parallel between experimental and computational research. Development of computational tools for both theoretically and experimentally oriented researchers is an area of focus.


  • Metabolism (Glycolysis, Pentose Phosphate Pathway)
  • Microcirculation (Conducted responses, remodelling of arterioles in vascular networks)
  • Synchronization of biological oscillators

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