Browse 6,486 peer-reviewed studies on electromagnetic field health effects from 4 research libraries.
Showing 100 studies (Microorganisms)
R.P. Blakemore, R.B. Frankel, A.J. Kalmijn · 1978
Mössbauer spectroscopy revealed that freshwater magnetotactic spirilla contain iron-rich particles of about 50 nanometers consisting primarily of magnetite. The authors demonstrate that these particles fall in the single magnetic domain size range and that a chain of such particles functions as a single magnetic dipole moment.
C. Tamburello, L. Dardanoni · 1978
Square-modulated 72 GHz microwaves reduced colony-forming units of Candida albicans compared with continuous-wave exposure. The study also examined how ambient temperature and different modulation frequencies affected cell sensitivity.
J. C. Corelli, R. J. Gutmann, S. Kohazi, J. Levy · 1977
A. W. Friend, E. D. Finch, H. P. Schwan · 1975
Jacqueline Segall, Robert Tjian, Janice Pero, Richard Losick · 1974
The sigma subunit of RNA polymerase from sporulating Bacillus subtilis is markedly inhibited in its ability to direct transcription of phage lambda DNA in vitro. Lambda DNA is transcribed only 9% as actively in early sporulating cells as in vegetative bacteria. Chloramphenicol treatment of sporulating cells rapidly restores sigma activity as measured in vitro. The hypothetical inhibitor is depleted exponentially with an apparent half-life of 11 min at 37°.
Mattern IE, Roberti B · 1974
Researchers used radiation-sensitive mutants of Uscherichin coli and Salmonella tuphimurcun in the study. The mutants were employed to identify environmental pollutants that damaze DN. Liver homogenates were added to the test system to imitate in vivo metabolism. The study also investigated the effects of 3 iHl% microwaves on hrologic Vival and mutation taduction.
D. Michael Bitz, Malcolm L. Sargent · 1974
The magnetic fields had no significant effect on growth rate or circadian period (conidiation rhythm) at P < 0.05. No reproducible changes in morphology, conidiation, or pigmentation were observed.
G. A. CORKER, S. A. SHARPE · 1974
Researchers studied the kinetics of the photo-induced P870* EPR signal in whole-cell Rhodospirillum rubrum at room temperature. At low actinic light intensity the signal growth appeared monotonic with a very slow second phase and the decay was biphasic. Increasing the light intensity caused a rapid initial rise to a plateau within 100 ms followed by slow growth and a monophasic decay.
C. M. B. Walker, K. G. McWhirter, W. A. G. Voss · 1974
Researchers examined the effect of 2450 MHz microwave radiation pulsed at 8KHz at a power density between 1 and 10 mW cm* on bacteriophage infection of E. coli, irradiating samples for 7 minutes. They compared the number of infective centers in irradiated samples with controls across 25 experiments. A Student's t-test on the combined data gave t=0.3815 with 48 degrees of freedom, showing about a 50% probability the difference was due to chance.
P. E. Hamrick, B. T. Butler · 1973
Researchers exposed four strains of Escherichia coli and one strain of Pseudomonas aeruginosa to continuous 2450 MHz microwave radiation for 12 hours at 60 mW/cm². The microwave power was adjusted so that the media temperature was held at 37 ± 0.5°C. Growth curves of exposed and control bacteria were compared and found to be the same within experimental error. At an absorbed dose of 259 mW/cm² with additional cooling to keep the temperature at 37°C, no difference in growth curves was detected. At an absorbed power of 450 mW/cm² with cooling, growth curves of exposed and control bacteria again showed no appreciable difference.
R. L. Vilenskaya et al. · 1972
P. C. B. Roberts · 1972
Researchers exposed Saccharomyces cerevisiae vegetative cells and ascospores to 2450 MHz microwaves using a hexane-cooled apparatus designed to separate thermal from non-thermal effects. At 40 watts without coolant flow, total loss of viability occurred after 30 seconds for vegetative cells and 40 seconds for spores, while suspension temperatures remained below 33°C.
Theodore L. Jahn, Eugene C. Bovee · 1971
Friend AW · 1970
A. M. Roberts · 1970
M. A. K. Hamid, W. M. Boerner, S. C. Tong · 1970
Researchers exposed potato-waste water to 2.45 GHz microwaves at 1.2 kW for 8 to 18 seconds in a rectangular waveguide. Bacterial counts decreased logarithmically with irradiation time. Chemical oxygen demand was higher in irradiated samples than in controls. The authors hypothesized that microwaves may stimulate aerobic bacteria and reduce photosynthetic bacteria, but noted these observations need confirmation.
RAYMOND A. MADSON et al. · 1970
Christopher S. Cox, Harold Klapper · 1970
J. Bilbrough · 1969
D. E. Carroll, Anthony Loh · 1969
S. J. Webb, A. D. Booth · 1969
Researchers prepared cells and their fractions and measured microwave absorption at various frequencies. DNA showed higher microwave absorption than RNA. The study found that microwave absorption by cells affects biological processes.
S. J. Webb, D. D. Dodds · 1968
Researchers exposed Escherichia coli B to 136 gc microwaves at about 10 W for up to 4 hours. When cells were exposed immediately after washing, no cell divisions occurred but cell counts did not decrease. When cells were pre-incubated for 90 minutes before exposure, cell numbers approximately doubled before inhibition began.
Samuel A. Goldblith, Daniel I. C. Wang · 1967
Researchers exposed suspensions of E. coli and B. subtilis spores to microwave energy at 2,450 MHz and conventional heating, comparing inactivation quantitatively. During transient microwave heating, E. coli showed a 6 log cycle reduction in viability, nearly identical to that predicted from conventional heating at the same time-temperature profile. B. subtilis spores heated at 100°C, in ice, and during transient heating showed identical inactivation by microwave and conventional heating.
J. W. Zahradnik, R. E. Stumbo · 1967
The apparatus was designed around equality of the Damkohler group (rL/uC). The test organism was a 10 °'celli per ml. suspension of Salmonella genftenberg 775W, and experiments were performed at 65.6°C and one replication at 68.3°C. Lethality predictions from the model agreed with prototype measurements at the 1% significance level for a diameter scale-up of 2 and a flow-rate scale-up of 4.
Carl M. Olsen, Clifford L. Drake, Stuart L. Bunch · 1966
Spores of Fusarium solani f. phaseoli treated with microwaves germinated on an "all-or-nothing" basis, while water bath treatment gave a conventional germination pattern. Microwave treatment at 2450 MHz of 0.1N NaOH solution produced hydrogen peroxide, whereas water bath heating to the same temperature did not. Microwave finish-drying of potato chips resulted in higher amounts of triglycerides, diglycerides, and longer chain aldehydes in the extracted oil. Mesophilic bacteria were reduced up to 99% and viable spores of Penicillium, Aspergillus, and Rhizopus were also reduced, while Saccharomyces cerevisiae cells heated to 56°C by microwaves had a respiration rate of 0.57 ul 02/min compared with 2.88 ul 02/min for water bath heating at the same temperature.