scholarly journals Modification ofS. cerevisiaeGrowth Dynamics Using Low Frequency Electromagnetic Fields in the 1-2 kHz Range

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Ján Barabáš ◽  
Roman Radil ◽  
Ivona Malíková
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Electromagnetic Fields ◽  
Proliferative Response ◽  
Low Frequency ◽  
Growth Dynamics ◽  
Magnetic Flux Density ◽  
Wild Type ◽  
Frequency Range ◽  
Ambient Conditions ◽  
Resonance Theory

This paper details our further experiments pertaining to the influence of low frequency electromagnetic fields (LF EMF) on the growth dynamics of two wild-typeSaccharomyces cerevisiaestrands. We opted to explore frequencies beyond the usual 50–60 Hz range, motivated by the ion parametric resonance theory and several studies which discovered and recorded endogenous biosignals in variousSaccharomyces cerevisiaestrands in the 0.4–2.0 kHz frequency range, most probably stemming from microtubules. Both yeast strands used in our experiments have been subjected to continuous 66-hour session of LF EMF exposure (frequencies 1.2, 1.4, 1.6, 1.8, and 2.0 kHz; average magnetic flux density 2.43 mT) under identical ambient conditions. Experiment results indicate a frequency-dependent proliferative response of both yeast strands.

scholarly journals Biological Effects of a Low-Frequency Electromagnetic Field on Yeast Cells of the Genus Saccharomyces Cerevisiae

2021 ◽  
Vol 21 (2) ◽  
pp. 34-41
Author(s):  
K Sladicekova ◽  
M Bereta ◽  
J Misek ◽  
D Parizek ◽  
J Jakus
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Electromagnetic Field ◽  
Magnetic Flux ◽  
Flux Density ◽  
Biological Effects ◽  
Low Frequency ◽  
Growth Dynamics ◽  
Yeast Cells ◽  
Magnetic Flux Density ◽  
Time Points

Abstract Background: Although the scientific community is extensively concerned with the effects of the EMF, the unambiguous explanation of its effects on living structures is still lacking. Goals: The goal of the study was to evaluate the effect of a low-frequency (LF) electromagnetic field (EMF) on the growth and multiplication of the yeast Saccharomyces cerevisiae. Methods: Yeast cells were exposed to a frequency of 900 Hz and a magnetic flux density of 2.3 mT. The duration of each experiment was 8 hours, in the beginning of the measurement the value of frequency, rms (root mean square) value of electric current (2 A), and magnetic flux density were fixed set on the exposure device. A paired experiment was performed, a sample exposed to EMF, and a sample shielded from the field. Subsequently, samples were taken every two hours, the number of cells was recorded, and then the concentration of the yeast cells was evaluated at time points. The time points reflected the exposure time of the samples exposed to EMF. Results: The results indicate that LF EMF at given parameters has an inhibitory effect on the growth and multiplication of yeast cells. Conclusion: Exposure to EMF can cause the differences in growth dynamics between cells exposed to the field and the unexposed ones.

Occupational exposure to extremely low-frequency magnetic fields near 20 kV, 3-phase shunt reactors at substations

2018 ◽  
Vol 53 (2) ◽  
pp. 149-152
Author(s):  
H. Pirkkalainen ◽  
T. Heiskanen ◽  
M. Penttilä ◽  
J. Elovaara ◽  
L. Korpinen
Keyword(s):  
Occupational Exposure ◽  
Magnetic Flux ◽  
Electromagnetic Fields ◽  
Health And Safety ◽  
Low Frequency ◽  
Worker Safety ◽  
Magnetic Flux Density ◽  
Eu Directive ◽  
Action Value ◽  
Shunt Reactors

Directive 2013/35/EU of the European Parliament and Council, among other things, sets values for the occupational exposure of workers regarding the health and safety risks arising from electromagnetic fields. In order to ensure worker safety, the Finnish national grid operator, Fingrid Oyj, conducted several measurements of electromagnetic fields at its substations. One of the goals of the measurements was to ensure that a magnetic flux density of 1000 µT (rms), set as the lower action value by the EU directive, was not reached in any location accessible to substation workers. The highest magnetic flux densities at substations can be found near shunt reactors and their cables, which is why the measurements were focused on those areas. The lower action value of 1000 µT (rms) was surpassed at two locations. This discovery led to immediate actions to prevent workers from accessing these locations.

scholarly journals Low Frequency Characteristics of TiO2(Rutile)–Glass Thick Films

1977 ◽  
Vol 4 (1) ◽  
pp. 1-7 ◽  
Author(s):  
B. Licznerski ◽  
K. Nitsch ◽  
B. Rzasa
Keyword(s):  
Relaxation Time ◽  
Dielectric Relaxation ◽  
Low Frequency ◽  
Frequency Characteristics ◽  
Electric Permittivity ◽  
Frequency Range ◽  
Ambient Conditions ◽  
Amorphous Glass ◽  
Tio2 Rutile ◽  
Normal Ambient

An analysis is made of the low-frequency characteristics of the permittivityε′and of tanδof a thick-film insulator containing rutile grains bonded with an amorphous glass. The appearance of dielectric relaxation associated with a maximum of tanδ, as well as characteristic Debye dispersions of the electric permittivity is observed. The relaxation time does not depend on the rutile concentration in the dielectric. An equivalent circuit describing the behaviour of a capacitor with such an insulator in the low frequency range is suggested. The experimental results are shown to be consistent with an analysis based on the assumption that a titanium ion relaxation process occurs in the rutile grains. In normal ambient conditions the influence of this kind of polarization disappears at frequencies higher than 102Hz;ε′and tanδthen change insignificantly and the value of tanδis conditioned by the hopping mechanism of conductivity in the glass and in rutile.

Electrical Properties Measurement of Rat Blood in 10 kHz-10 MHz

2013 ◽  
Vol 774-776 ◽  
pp. 836-839
Author(s):  
Gun Li
Keyword(s):  
Electromagnetic Fields ◽  
Biological Effects ◽  
Low Frequency ◽  
Electromagnetic Property ◽  
Critical Issue ◽  
Dielectric Dispersion ◽  
Frequency Range ◽  
Electrical Parameters ◽  
Rat Blood ◽  
Lcr Meter

Electromagnetic property of biological tissue is a critical issue for studying the biological effects of electromagnetic fields. In order to investigate the electrical parameters of rat blood and dispersion spectrum within the low-frequency, dielectric and conductivity parameters of rat blood was measured via HP4275A Multi Frequency LCR Meter in low frequency range (10 kHz-10 MHz), dispersive characteristics of blood electrical parameters was defined within the low-frequency. Dielectric properties of the measurement were used to compare with the theory of Cole-Cole fitting, and the fitting result shows that the Cole-Cole theory can well reflect the dielectric dispersion characteristics of rat blood. These results can be used to studying further biological effects of different frequencies electromagnetic fields.

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

Dynamic Damping and Stiffness Characteristics of the Rolling Tire

2001 ◽  
Vol 29 (4) ◽  
pp. 258-268 ◽  
Author(s):  
G. Jianmin ◽  
R. Gall ◽  
W. Zuomin
Keyword(s):  
Dynamic Behavior ◽  
Variable Parameter ◽  
Low Frequency ◽  
Vertical Load ◽  
Frequency Range ◽  
Inflation Pressure ◽  
Vehicle Simulation ◽  
Dynamic Damping ◽  
Speed Range ◽  
Stiffness Characteristics

Abstract A variable parameter model to study dynamic tire responses is presented. A modified device to measure terrain roughness is used to measure dynamic damping and stiffness characteristics of rolling tires. The device was used to examine the dynamic behavior of a tire in the speed range from 0 to 10 km/h. The inflation pressure during the tests was adjusted to 160, 240, and 320 kPa. The vertical load was 5.2 kN. The results indicate that the damping and stiffness decrease with velocity. Regression formulas for the non-linear experimental damping and stiffness are obtained. These results can be used as input parameters for vehicle simulation to evaluate the vehicle's driving and comfort performance in the medium-low frequency range (0–100 Hz). This way it can be important for tire design and the forecasting of the dynamic behavior of tires.

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