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Sökning: FÖRF:(Bertil Persson) > Konferensbidrag

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1.
  • Persson, Bertil R, et al. (författare)
  • Survival of rats with N29 brain tumours after irradiation with 5 or 15 Gy and immunization with IFN-gamma secreting tumour cells
  • 2008
  • Ingår i: BioMedical Engineering and Informatics : New Development and the Future - Proceedings of the 1st International Conference on BioMedical Engineering and Informatics, BMEI 2008 - New Development and the Future - Proceedings of the 1st International Conference on BioMedical Engineering and Informatics, BMEI 2008. - 9780769531182 ; 2, s. 243-247
  • Konferensbidrag (refereegranskat)abstract
    • Intra cerebral tumours were inoculated into the brain of Fischer-344 syngeneic rats. After one week they were treated with either 5 or 15 Gy of Co-60-gamma radiation. The first immunization was given 1 hour before the radiation treatment and then two more times with 14-day intervals. Immunization was performed with 3 x 10(6) radiation sterilized IFN-gamma secreting tumour cells (N29) injected intraperitoneally. Neither radiation therapy with 5 or 15 Gy nor immunization with N29 cells alone had any significant effect on the length of survival of N29 tumour bearing rats. But radiation therapy with 5 Gy combined with immunization with IFN-gamma secreting syngeneic N29 cells resulted in 63 % complete remissions and significantly (p < 0.05) increased survival for the tumour bearing rats. Corresponding combination with 15 Gy RT resulted in 50% complete remissions. There is a possibility of a synergistic effect by optimal combination of radiation therapy and immunization.
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2.
  • Salford, Leif, et al. (författare)
  • The mammalian brain in the electromagnetic fields designed by man with special reference to blood-brain barrier function, neuronal damage and possible physical mechanisms
  • 2008
  • Ingår i: PROGRESS OF THEORETICAL PHYSICS SUPPLEMENT. - 0375-9687. ; :173, s. 283-309
  • Konferensbidrag (refereegranskat)abstract
    • Life oil earth was formed during billions of years, exposed to, and shaped by the original physical forces such as gravitation, cosmic irradiation, atmospheric electric fields and the terrestrial magnetism. The Schumann resonances at 7.4 Hz are all example of oscillations possibly important for life.(1)) The existing organisms are created to function in harmony with these forces. However, in the late 19th century mankind introduced the use of electricity, in the early 20th century long-wave radio and in the 1940-ies short-wave radio. High frequency RF was introduced in the 50-ies as FM and television and during the very last decades, microwaves of the modern communication society spread around the world. Today, however, one third of the world's population is owner of the microwave-producing mobile phones and an even larger number is exposed to the cordless RF emitting systems. To what; extent are all living organisms affected by these, almost everywhere present radio frequency fields? And what will be the effects of many years of continuing exposure? Since 1989 Our group has studied the effects upon the mammalian blood-brain barrier (BBB) in rats by non-thermal radio frequency electromagnetic fields (RF-EMF). These have been shown to cause significantly increased leak-age of the rats' own blood albumin through the BBB of exposed rats, at energy levels of 1W/kg and below, as compared to non-exposed animals in a total series of about two thousand animals.(2)-6)) One remarkable observation is the fact that the lowest energy levels, with whole-body average power densities below 10mW/kg, give rise to the most pronounced albumin leakage. If mobile communication, even at extremely low energy levels, causes the users' own albumin to leak out through the BBB, also other unwanted and toxic molecules in the blood, may leak into the brain tissue and concentrate in and damage the neurons and glial cells of the brain. In later studies we have shown that a 2-h exposure to GSM 915 MHz, at non-thermal SAB-values of 0.2, 2 and 200 mW/kg, gives rise to significant neuronal damage, seen not only 50 days after the exposure 7) but also after 28 days but not after 14 days. Albumin extravasations and uptake into neurons was enhanced after 14 clays, but not after 28.(8)) in our continued research, also the non-thermal effects oil tissue structure and memory function of long-term exposure for 13 months are studied.(9)) We have also performed microarray analysis of brains from rats exposed to short term GSM both at 1,800 MHz and at 900MHz and have found significant effects upon gene expression of membrane associated genes as compared to control animals.(10),11)) Most of our findings support that living organisms are affected by the non-thermal radio frequency fields. Some other Studies agree while others find no effects. The mechanisms by which the EMFs may alter BBB permeability are not Well Understood. At low field strengths, the effects on body temperature are negligible and thus heating effects are not involved. A change in the physicochemical characteristics of membranes has been suggested as a cause.(12)) We have performed experiments to verify a quantum mechanical model for interaction with protein-bound ions. Our results show that controlled frequency and amplitude of ELF EM fields upon spinach plasma vesicles can steer transport over the membrane.(13)) This may be a first proof of a resonance phenomenon where appropriate levels of frequency and amplitude in the right combination have the potency to communicate with the biology of membranes and transport systems. Our study has prompted Lis to elaborate on magnetic resonance models; the Ion Cyclotron Resonance (ICR) model and the Ion Parametric Resonance (IPR) Model in an attempt to explain the occurrence of resonance frequencies. This is extensively described here under the heading: Mechanisms behind the effects of electromagnetical fields upon biology. We also bring forward the concept of solitons being active in membranes and DNA/RNA-transcription as a, possible mean to understand and prove the biological effects of EMF. The Nishinomiya-Yukawa International and Interdisciplinary Symposium 2007 raised the question: What is Life? An obvious and simple answer could be: It is DNA! The DNA strand can be looked upon as an antenna resonating in the microwave band 6GHz with its harmonics and subharmonics.(14)-18)) If this holds true, the dramatic situation might exist, that all living organisms have a receptor for the newly constructed and world-wide man-made microvaves, leading to a direct effect upon the function of DNA - in concordance with our experimental findings! Our generation invented the microwave emitters. We now have in imperative obligation to further investigate the links between EMF and biology in order to prevent possible detrimental effects of the microwaves.
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3.
  • Persson, Bertil (författare)
  • Thaumasite sulphate attack on self-compacting concrete with limestone filler
  • 2007
  • Ingår i: Sustainable Construction Materials and Technologies. - 9780415446891 ; , s. 461-470
  • Konferensbidrag (refereegranskat)abstract
    • The paper deals with durability of Self-Compacting Concrete with limestone filler during Thaumasite Sulphate Attack. For this purpose six concrete with varying amounts of limestone filler, particle size of limestone filler, pressure height during casting and mixing order were studied. One normal concrete (without limestone filler) with vibrator compaction was studied in parallel. In the ongoing experiment the specimen are kept at 5 degrees C in a solution sodium sulphate with circulation with a propeller. The solution is being change every third month. Only low-alkali sulphate resistant cement was used as binder but limestone filler seem to have some effect on the hydration as well. The results show a sudden breakdown after five years due to Thaumasite Sulphate Attack similar to salt-frost scaling of all concrete with limestone filler. The normal concrete without limestone filler is still performing well after six years in the very same basin as the concrete with limestone filler. The ongoing research was performed at Lund Institute of Technology, Lund, Sweden, 2000-2006.
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5.
  • Persson, Bertil R.R., et al. (författare)
  • Effects of microwaves from GSM mobile phones on the blood-brain barrier and neurons in rat brain
  • 2005
  • Ingår i: PIERS 2005 - Progress in Electromagnetics Research Symposium, Proceedings. - 1933077077 - 9781933077079 ; , s. 638-641
  • Konferensbidrag (refereegranskat)abstract
    • Our group has since 1988 studied the effects of different intensities and modulations of 915MHz RF in a rat model where the exposure takes place in a TEM-cell during various time periods and post exposure recovery times. The power fed into TEM-cells was 0.125, 1.25, 12.5 or 125mW corresponding to whole body SAR (determined experimentally): 0.2, 2, 20 or 200mW/kg. The rats were awake and not restrained during exposure and after the recovery period the animals were anaesthetized and sacrificed by perfusion-fixation with 4% formaldehyde. Paraffin embedded 5 μm. thick brain slices were stained for albumin by applying albumin antibodies (Dakopatts), by which albumin is revealed as brownish discolorations. Dark neurons were revealed by staining for RNA/DNA with cresyl violet. In series of more than 1800 Fisher rats, we have proven that sub thermal power levels from both pulse-modulated and continuous RF fields - including those from real GSM mobile phones - have the potency to significantly open the BBB for the animals' own albumin (but not fibrinogen) to pass out into the brain and to accumulate in the neurons and glial cells surrounding the capillaries. Albumin extravasations are most prominent at the lower SAR values. This dose-response behaviour suggests some kind of energy or electromagnetic field strength windowing effect. A linear dose-response relationship for dark neurons was found at 50 days after exposure, with most prominent occurrence at SAR 200mW/kg.
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9.
  • Munck af Rosenschöld, Per, et al. (författare)
  • Current status of dosimetry at the boron neutron capture therapy facility at Studsvik, Sweden
  • 2002
  • Ingår i: Research and Development in Neutron Capture Therapy. - 9788832329094 ; , s. 437-441
  • Konferensbidrag (refereegranskat)abstract
    • The beam was successfully characterized in air and in phantom using various radiation dosimeter:,. The determination of the thermal neutron and photon components of the mixed beam in phantom can be determined with acceptable uncertainties, while the uncertainty of the high-energy neutron component is considerable but of limited clinical significance. The beam intensity is sufficiently high for reasonably short treatment times. A novel approach to in-vivo dosimetry and quality assurance of treatment time in terms of monitor units was introduced in order to comply with national regulations regarding radiation therapy.
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10.
  • Persson, Bertil, et al. (författare)
  • High performance self compacting concrete, HPSCC
  • 2002
  • Ingår i: Proceedings of the 6th International Symposium on the Utilization of High Strength/ High Performance Concrete, Leipzig, June 2002. - 9783934178182 ; , s. 1273-1290
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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  • Resultat 1-10 av 31

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