William M. Carey and the nonlinear frequency dependence of low frequency attenuation in sandy sediments

2014 ◽  
Vol 135 (4) ◽  
pp. 2260-2260
Author(s):  
Allan D. Pierce ◽  
William L. Siegmann ◽  
Jon M. Collis ◽  
Richard B. Evans ◽  
Jason Holmes
Keyword(s):  
Frequency Dependence ◽  
Low Frequency ◽  
Nonlinear Frequency ◽  
Sandy Sediments

Nonlinear frequency-dependent attenuation in sandy sediments

2007 ◽  
Vol 121 (5) ◽  
pp. EL218-EL222 ◽  
Author(s):  
J. D. Holmes ◽  
W. M. Carey ◽  
S. M. Dediu ◽  
W. L. Siegmann
Keyword(s):  
Nonlinear Frequency ◽  
Frequency Dependent ◽  
Sandy Sediments

Evidence for nonlinear frequency dependence of attenuation in an East China Sea environment

2004 ◽  
Vol 115 (5) ◽  
pp. 2551-2551 ◽  
Author(s):  
David P. Knobles ◽  
Robert A. Koch ◽  
James H. Miller ◽  
Gopu R. Potty
Keyword(s):  
Frequency Dependence ◽  
East China Sea ◽  
East China ◽  
Nonlinear Frequency ◽  
China Sea

Low-frequency respiratory mechanical impedance in the rat

1987 ◽  
Vol 63 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Z. Hantos ◽  
B. Daroczy ◽  
B. Suki ◽  
S. Nagy
Keyword(s):  
Frequency Dependence ◽  
Chest Wall ◽  
Low Frequency ◽  
Mechanical Impedance ◽  
Total Resistance ◽  
Low Frequencies ◽  
Chest Wall Compliance ◽  
Before And After ◽  
Airway Opening ◽  
Wall Compliance

modified forced oscillatory technique was used to determine the respiratory mechanical impedances in anesthetized, paralyzed rats between 0.25 and 10 Hz. From the total respiratory (Zrs) and pulmonary impedance (ZL), measured with pseudorandom oscillations applied at the airway opening before and after thoracotomy, respectively, the chest wall impedance (ZW) was calculated as ZW = Zrs - ZL. The pulmonary (RL) and chest wall resistances were both markedly frequency dependent: between 0.25 and 2 Hz they contributed equally to the total resistance falling from 81.4 +/- 18.3 (SD) at 0.25 Hz to 27.1 +/- 1.7 kPa.l–1 X s at 2 Hz. The pulmonary compliance (CL) decreased mildly, from 2.78 +/- 0.44 at 0.25 Hz to 2.36 +/- 0.39 ml/kPa at 2 Hz, and then increased at higher frequencies, whereas the chest wall compliance declined monotonously from 4.19 +/- 0.88 at 0.25 Hz to 1.93 +/- 0.14 ml/kPa at 10 Hz. Although the frequency dependence of ZW can be interpreted on the basis of parallel inhomogeneities alone, the sharp fall in RL together with the relatively constant CL suggests that at low frequencies significant losses are imposed by the non-Newtonian resistive properties of the lung tissue.

scholarly journals CT2A Cell Viability Modulated by Electromagnetic Fields at Extremely Low Frequency under No Thermal Effects

2019 ◽  
Vol 21 (1) ◽  
pp. 152 ◽  
Author(s):  
Olga García-Minguillán ◽  
Raquel Prous ◽  
Maria del Carmen Ramirez-Castillejo ◽  
Ceferino Maestú
Keyword(s):  
Cell Viability ◽  
Frequency Dependence ◽  
Electromagnetic Fields ◽  
Thermal Effects ◽  
Low Frequency ◽  
Human Beings ◽  
Cellular Mechanisms ◽  
Low Frequencies ◽  
Hsp90 Expression

The effects produced by electromagnetic fields (EMFs) on human beings at extremely low frequencies (ELFs) have being investigated in the past years, across in vitro studies, using different cell lines. Nevertheless, the effects produced on cells are not clarified, and the cellular mechanisms and cell-signaling processes involved are still unknown. This situation has resulted in a division among the scientific community about the adequacy of the recommended level of exposure. In this sense, we consider that it is necessary to develop long-term exposure studies and check if the recommended levels of EMFs are under thermal effects. Hence, we exposed CT2A cells to different EMFs at different ELFs at short and long times. Our results showed frequency dependence in CT2A exposed during 24 h to a small EMF of 30 μT equal to those originated by the Earth and frequency dependence after the exposure during seven days to an EMF of 100 µT at different ELFs. Particularly, our results showed a remarkable cell viability decrease of CT2A cells exposed to EMFs of 30 Hz. Nevertheless, after analyzing the thermal effects in terms of HSP90 expression, we did not find thermal damages related to the differences in cell viability, so other crucial cellular mechanism should be involved.

Low-frequency ac electroporation shows strong frequency dependence and yields comparable transfection results to dc electroporation

2012 ◽  
Vol 160 (3) ◽  
pp. 570-576 ◽  
Author(s):  
Yihong Zhan ◽  
Zhenning Cao ◽  
Ning Bao ◽  
Jianbo Li ◽  
Jun Wang ◽  
...  
Keyword(s):  
Frequency Dependence ◽  
Low Frequency
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