The cerebral magnetic field of the auditory steady-state response (SSR) to sinusoidal amplitude-modulated (SAM) tones was recorded in healthy humans. The waveforms of underlying cortical source activity were calculated at multiples of the modulation frequency using the method of source space projection, which improved the signal-to-noise ratio (SNR) by a factor of 2 to 4. Since the complex ampl...

Cortical visual evoked potentials (VEPs) in response to gratings temporally modulated in counterphase were recorded in normal and dark-reared pigmented rats. Temporal modulation was either sinusoidal (0.25-15 Hz, steady state condition) or abrupt (0.5 Hz, transient condition). In normals, the amplitude spectrum of contrast VEPs has two peaks (at about 0.5 and 4 Hz) and a high temporal frequency...

Pressure-induced skin blood flow responses measured via laser Doppler flowmetry are commonly reported in the time domain. The usefulness of spectral analysis in examining blood flow control mechanisms has been demonstrated, but traditional Fourier analysis does not provide sufficient resolution to reveal characteristic low frequencies. Time-frequency (wavelet) analysis was performed on 10 subje...

ActiGraph acceleration data are processed through several steps (including band-pass filtering to attenuate unwanted signal frequencies) to generate the activity counts commonly used in physical activity research. We performed three experiments to investigate the effect of sampling frequency on the generation of activity counts. Ideal acceleration signals were produced in the MATLAB software. T...

The endogenous Cl- conductance of Spodoptera frugiperda (Sf9) cells was studied 20-35 h after plating out of either uninfected cells or cells infected by a baculovirus vector carrying the cloned beta-galactosidase gene (beta-Gal cells). With the cation Tris+ in the pipette and Na+ in the bath, the reversal potential of whole-cell currents was governed by the prevailing Cl- equilibrium potential...

Introduction:  The  use  of  mobile  communication  systems  has  dramatically  increased  over  the  past  decade. Although many studies have been performed to determine the effect of radio frequency (RF) but  less attention has been paid to the possible biological impact of exposure to extremely low frequency  (ELF) components.   The objective of this study is two folds. One is to design the ...

We discovered kHz QPOs in 80 archived RXTE observations from the peculiar low-mass X-ray binary (LMXB) Circinus X-1. In 11 cases these appear in pairs in the frequency range of ∼230 Hz to ∼500 Hz for the upper kHz QPO and ∼56 Hz to ∼225 Hz for the lower kHz QPO. Their correlation with each other, which is similar to that of frequencies of kHz QPO pairs in other LMXBs containing a neutron star, ...

Near-infrared spectroscopy (NIRS) was used to investigate the cerebral oxygenation of Moyamoya and healthy subjects. Continuous recordings of NIRS signals for 20 min (20 min signals) were obtained from 17 healthy subjects (age: 37.4 ± 11.3) and 17 Moyamoya subjects (age: 40.1 ± 11.2). Spectral analysis based on wavelet transformation identified five frequency intervals (I, 0.0095 Hz to 0.02 Hz;...

The purpose of this paper was to determine the effects of stimulation pattern and frequency on repetitive human knee movements. Quadriceps femoris muscles were stimulated against a load equal to 10% of each subject's maximum voluntary isometric force. The main variable of interest was the number of repetitions in which the leg reached a target angle of 40 degrees of knee extension. Sixteen diff...

BACKGROUND/AIMS Cardiac action potential duration (APD) is regulated by heart rate, leading to the trans-membrane movement of inorganic ions. Whether the alteration of heart rate can affect the expression of transient receptor potential canonical channels (TRPCs), further studies should be made. We investigated the changes of APD at different stimulus frequencies and their influences on the exp...