Bio and Environmental Physics
Experimental Biophysics (Prof. Arvi Freiberg)
We investigate pressure-induced structural changes in pigment-protein complexes of photosynthetic bacteria by using various spectroscopic methods. Under high hydrostatic pressure applied on protein environment hydrogen bonds can break and conformational changes such as rotation of acetyl group can occur in certain sites. Structural changes reveal itself through the shift and broadening of spectral bands of amino acids and bacteriochlorophyll pigments. New equipment enables us to measure apart from infrared spectra of pigments also ultraviolet spectra of proteins under pressure. Through the analysis of pressure-induced spectral changes we expect to show that the protein scaffold is a special structuring environment that essentially controls the energetics, kinetics, and directionality of light-harvesting and electron transfer in a pigment-protein complex. Apart from formerly studied objects we are experimenting with pigment-protein complexes of Thermochromatium tepidum and Thiorhodovibrio (Trv) strain 970, where the effect of the concentration of calcium ions on the structure and spectra becomes significant.
Theoretical and Computational Biophysics (Assoc. Prof. Juha Matti Linnanto)
Our research is aimed towards the atomic-level understanding of the structure and the function of biomolecules, biomolecular aggregates, proteins, and protein complexes. For this purpose, well known modern quantum chemical and force field calculation methods are applied to test various theoretical models. The calculation methods and the theoretical models being used enable us to investigate systems of interest from the atomic scale to the biomolecular scale. Topics of special interest are:
- spectroscopic properties of photosynthetic pigment-protein complexes,
- light harvesting and excitation energy transfer processes in photosynthetic pigment-protein complexes and their superstructures,
- structure and function of biomolecular surfaces.
In the Atmospheric Physics Lab (led by Assoc Prof Piia Post) we study weather and climate, our main research topics are following:
Anthropogenic climate forcing
Climate Change in the Baltic Sea Region
Airborne nanoparticles and their role in meteorological processes
A key for understanding the microphysical basic processes of the weather and climate is the particle formation and growth from one nanometre up to cloud drops. Leadership in the electric mobility spectrometry of airborne nanoparticles provides a good start for the research group to understand this chain of physical processes and to develop adjusted numerical weather and climate models. The theory of nanoparticle formation and growth, a database of measurements, and advanced physical and optical models of aerosols and cloud particles will be developed. The results will be applied composing new radiative transfer blocks for numerical weather and climate models and applied in national and international environmental weather and climate programs. Studies are supported by the Estonian Science Infrastructure Roadmap Project “Estonian Environmental Observatory”, which includes corporate developing of the Estonian SMEAR station.
Principal investigator Dr Urmas Hõrrak, Laboratory of Environmental Physics
Chemical composition and interactions in atmosphere: from gases to aerosols and climate change
Principal investigator Dr Heikki Junninen, Laboratory of Environmental Physics
Radioactivity in the environment and the resulting radiation doses are, besides a national monitoring programme, objects of scientific research in all neighbouring states and cannot be neglected in Estonia as well. This is an obligation by international agreements, EURATOM treaty and corresponding legal acts, but there is also the need to provide professional information, to measure the environmental radioactivity and interpret the monitoring results, to evaluate current situation and make prognoses for future developments in the field of radiation protection, in cases of emergencies, etc. Main research is focused on the following topics. a) Environmental radioactivity research in Estonia for obtaining information about transport and migration of natural and artificial radionuclides in the soil, air and water, as well as radioecological pathways of radionuclides and the formation of irradiation dose in radioactive waste management and impact sources from energy production. b) Development and implementation of gamma-spectrometry and methods for numerical modelling, including low-energy high-purity Ge (HPGe) gamma-spectrometry, validating quality measures for quantitative analysis of environmental samples through routine international proficiency tests practice, transport models of radionuclides and radioecological models of radionuclide pathways in the air, water and soil, gamma-radiation resonance forward-scattering models of ultra fine interactions. c) Development of analysis methods for alpha- and beta-radiation detection in environmental applications.
Principal investigator Dr Madis Kiisk, Laboratory of Environmental Physics