Manuel Murbach (see page 3, Student Platform Awards)
First Place Poster presentation (P-40): DOSIMETRIC ASSESSMENT OF C. ELEGANS EXPOSURE IN VIVO TO 900 MHZ ELECTROMAGNETIC FIELDS.
Co-authors: M. Murbach1,3, M. Mevissen2, N. Kuster1; 1IT’IS Foundation, Zurich, Switzerland. 2Dept Clinical Research and Veterinary Public Health, Bern, Switzerland. 3Swiss Federal Inst of Tech (ETH), Zurich, Switzerland.
2nd Place Poster Presentation (P-78):
ASSESSMENT OF THE SAR FROM HANDS-FREE KITS FOR MOBILE PHONES.
Co-authors: S. Kuehn, E. Cabot, A. Christ, M. Capstick, N. Kuster; IT’IS Foundation / ETH Zurich, Zurich, Zurich, Switzerland.
EMF Risk Assessment of Hands-free Kits used with Mobile Phones
Sven Kuehn’s PhD research focused on the evaluation of human exposure to radio-frequency electromagnetic fields. The topics included the development of procedures, methods and instrumentation to support dosimetry in epidemiological studies, the development of procedures for compliance testing as well as the characterization of human exposure from various communication devices in general.
A recent study, presented at the 2009 Joint BEMS and EBEA meeting in Davos, aimed at the evaluation of hands-free kits used with mobile phones. The main objectives of the study were to evaluate the reduction or enhancement of human exposure when using mobile phones with hand-free kits and whether hands-free kits require compliance testing since ambiguous information existed in the literature.
In this study procedures for the testing of hands-free kits under worst-case and realistic usage conditions were developed and applied to a set of devices under test. From the results it can be concluded that hands-free kits reduce the exposure of the entire head compared to the mobilephone operated at the head, but there might be a very localized exposure enhancement in the ear. Specific compliance testing of hands-free kits is not necessary. Future research concerning hands-free kits as well as other body and head mounted devices is required in order to more accurately quantify the exposure of specific tissue and brain regions. This can then be applied to estimate the exposure of specific functional regions in epidemiological studies as well as to establish a more meaningful dosimetry for non-thermal biological effects.
3rd Place Poster Presentation (P-180):
Thermosensor protein GrpE of heat shock protein HSP70 system as target for electromagnetic fields.
Co-authors: Christian Beyer1, Ilian Jelesarov2, Philipp Christen2 and Jürg Fröhlich1; 1Information Tech and Electrical Engineering, ETH Zurich, Zurich, Switzerland. 2Biochemistry, Univ of Zurich, Zurich, Switzerland.
Christian Beyer’s project is carried out as a collaborative effort of the ‘Group for Electromagnetics in Medicine and Biology’ hosted by the Laboratory for Electromagnetic Fields and Microwave Electronics at the ETH Zurich(1) and the Department of Biochemistry at the University of Zurich(2), bringing together engineers and biologists. The experimental set-up for the exposure of the protein solution to electromagnetic fields (EMF) has been constructed in the workshop at ETH and installed in the circular dichroism (CD) spectropolarimeter of the Department of Biochemistry at the University of Zurich, where experiments and evaluations are also carried out by collaborators of both institutions.
The ‘Group for Electromagnetics in Medicine and Biology’ conducts research toward applications of electromagnetic and optical principles in medical technology as well as in biomedical research. In close collaboration with academia and industry various projects are run covering magnetic resonance technology, optical spectroscopy, bio-impedance spectroscopy, wireless technologies for health care as well as risk assessment of electromagnetic fields. Regarding bioelectromagnetics, different projects including the potential effects of electromagnetic fields on biomolecular structures and cells as well as contributions to exposure assessment for epidemiological studies are conducted.
The focus of the research group of the Department of Biochemistry participating in this project is on molecular chaperones, in particular the DnaK/DnaJ/GrpE-system of Escherichia coli. GrpE, the experimental object in the project, is the nucleotide exchange factor in that system. In the past 12 years, the group has made several definitive contributions to the field, such as the introduction of fluorescence-labelled peptides for assessing the kinetics of molecular chaperone action, the discovery of the thermosensor function of GrpE, the concept of cis-action of DnaJ on DnaK in ternary (ATPDnaK)proteinDnaJ complexes, and the direct heat-shock response of the DnaK/ DnaJ/GrpE system.
The aim of the project presented at BioEM 2009 in Davos, Switzerland, is to design a novel real-time experiment with high reproducibility for the investigation of potential interaction of EMF on well-defined biological macromolecules, like proteins, in particular GrpE. By utilising proteins the complexity of the investigated object is reduced from the cellular to the molecular level. The new experimental set-up consists of a thermostatted exposure chamber mounted in the measurement compartment of a spectropolarimeter. With this arrangement solutions of biomacromolecules proteins can be exposed to EMF while simultaneously monitoring their conformational equilibrium in terms of secondary structure content (via measurement of the ellipticity), and the effect of the temperature on that equilibrium. Thus, the point of observation becomes identical with the potential interaction site in space and time, which will allow for the detection of even small effects of EMFs. The novel experimental unit facilitates the performance of strictly controlled realtime measurements, supports all commonly used study protocols, and allows for arbitrary pulsed exposure durations with user defined EMFs including DVBT, GSM and UMTS signals. The protein GrpE belonging to the Hsp70 chaperone system of E. coli turned out to be longterm stable for this kind of experiment. The well-defined temperature-dependence of the conformational equilibrium of GrpE may be expected to allow unequivocal differentiation between thermal and non-thermal effects of irradiation.
Future work will focus on investigating potential direct effects of RF and ELF electromagnetic field exposure on GrpE’s conformation and the kinetics of its change. If a potential effect is observed, the threshold in terms of the magnitude of the electromagnetic field can be obtained together with the frequency ranges where it occurs. Once an effect is defined and its thresholds are found, the molecular mechanisms may be explored in detail by genetic engineering of GrpE, e.g. by deleting or introducing positively or negatively charged residues.
Marie-Christine Gosselin (see page 4, Student Platform Awards)
4th Place Poster Présentation (P-33): CORELATION OF THE EXPOSURE OF MOBILE PHONES ASSESSED IN SAM BY APPLYING STANDARD PROCEDURES WITH THE SAR IN ANATOMICAL HUMAN HEADS.
Co-authors: M. Gosselin1, M. Zefferer1, P. Crespo Valero3, A. Christ2, S. Kuehn1, N. Kuster1; 1BioEM Group, Integrated Systems Laboratory, ETH Zurich, Zurich, Switzerland. 2IT’IS Foundation, Zurich, Switzerland. 3SPEAG, Zurich, Switzerland.
Also presented at this meeting was the NFP57 study “Correlation of the Exposure of Mobile Phones Assessed in SAM by Applying Standard Procedures with the SAR in Anatomical Human Heads’’. Using various virtual brain regions on SAM, correlation factors have been developed to estimate the exposure of certain brain regions in an anatomical head. This set of correlation factors has been tested by exposing SAM and two anatomical heads to three realistic mobile phones. Future work will aim at optimizing these factors and implementing the outcome in SAR assessment systems used to estimate the tissue region specific SAR. This implementation will provide novel dosimetric measures, i.e., brain-region specific SAR, to epidemiological research as well as better information to the general public about which regions of the head are dominantly exposed by mobile phone usage.