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PubMed2002

Ship recognition via its radiated sound: the fractal based approaches.

Due to the complexity of its radiated sound, ship recognition is difficult. Fractal approaches are proposed in this study, including fractal Brownian motion based analysis, fractal dimension analysis, and wavelet analysis, to augment existing feature extraction methods that are based on spectrum analysis. Experimental results show that fractal approaches are effective. When used to augment two traditional features, line and average spectra, fractal approaches led to better classification results. This implies that fractal approaches can capture some information not detected by traditional approaches alone.

Journal Article↗

PubMed1995

[Methodology in the analysis of asymmetry in fluctuations of heart rate].

Time series of R-R intervals show fluctuations which are neither symmetric regarding the changes in length of heart beats nor regarding the number of heart beats during the phases of heart rate acceleration and deceleration. These features of heart rate variability cannot be quantified by the analysis of the beat-to-beat variability or by the spectrum analysis of heart rate. The analysis of asymmetry using the distribution function of the differences between consecutive R-R intervals creates measures for the total, central, and peripheral asymmetry. These measures quantify different aspects of the shape of the distribution function. The asymmetry measures are either based on the amount of difference between consecutive R-R intervals or the number of lengthening R-R intervals in a sequence of heart beats. The analysis of asymmetry of R-R interval time series shows differences among test subjects during rest.

Circadian Rhythm↗

PubMedDate not supplied

Analysis of laser Doppler flux motion in man: comparison of autoregressive modelling and fast Fourier transformation.

In order to investigate laser Doppler (LD) flux motion in healthy subjects and patients with peripheral arterial occlusive disease (PAOD), spectrum analysis of LD signals is needed. Autoregressive analysis (AR) is presented as an alternative method of power spectrum estimation. This procedure is compared to the commonly used fast Fourier transform algorithm (FFT) by describing the analytical power of both spectra in the analysis of flux motion waves. LD signals were recorded from the forefoot of 8 healthy volunteers and 11 patients with different degrees of PAOD. The flux, concentration of moving blood cells and velocity signal was digitized and stored for off-line analysis. Special software was designed to calculate AR and FFT spectra of the LD signals and to compare the suitability of both methods for the spectral analysis of LD recordings. Additionally, three-dimensional spectrum diagrams were calculated to demonstrate time-dependent flux changes during standardized provocation maneuvers. AR facilitates the determination of frequency and amplitude of flux motion waves as compared to the FFT. Low frequency-large amplitude waves (LF waves) were detected in both groups. High frequency-small amplitude waves (HF waves), which predominantly appear in severe ischemia, were observed in 7 of the 11 patients and in 2 of the 8 controls. The spectra revealed pulsatile waves in all healthy controls, but only in 1 of the 11 patients. AR modelling allows a reliable description of important flux motion components and has considerable advantages in spectral estimation of LD signals as compared to the FFT.

Algorithms↗

PubMed2002

The origins of physiological tremor as deduced from immersions of the finger in various liquids.

To investigate the influence of gravity on physiological tremor during a holding stretch of the finger, tremor during immersion of the finger in liquids was measured. Liquids with various densities and various coefficients of viscosity were used. Tremor was detected using an acceleration sensor, and power spectrum analysis was performed on the acceleration signal of the tremor. The total power of the tremor spectrum decreased with an increase of the density and an increase of the coefficient of viscosity, the high frequency domain of the tremor spectrum showing a larger decrease than the low frequency domain. Linear regression analysis showed that the viscosity of the liquid had a larger effect on tremor than the buoyancy due to the liquid. A model was proposed for tremor during immersion of the finger in liquid. The effect of the buoyancy and the viscosity on tremor was examined using the proposed model. The origin of two frequency bands in the tremor spectrum was verified by both the immersion experiment and the proposed model. The stretch-reflex system via the spinal cord produced a high frequency band around 25 Hz, while the supraspinal system caused a low frequency band around 10 Hz. The neuromuscular function of the human body was evaluated using the amplitude and the frequency of tremor.

Acceleration↗

PubMed1989

Altered estrogen receptor system in estrogen-unresponsive human endometrial adenocarcinoma cells.

Previous studies from our laboratories demonstrated that cells from a human endometrial adenocarcinoma cell line (Ishikawa) responded to estradiol whereas cells from another endometrial cancer line (HEC-50) did not. In an attempt to identify factors responsible for the observed estrogen insensitivity we compared the characteristics of the estradiol receptor (ER) systems in Ishikawa and HEC-50 cells. Saturation analyses of cytosolic estrogen binders were performed over a 0.1-70 nM range of [3H]estradiol concentrations. Equilibrium dissociation constants and number of binding sites were determined by graphic analysis of Scatchard plots or computed by applying Fourier-derived affinity spectrum analysis (FASA) of the binding data. No significant differences were noted in the dissociation constants (Kd approx. 0.6 nM) or number of binding sites (approx. 6-10 fmol/mg protein) for the single binder that could be evaluated by the graphic method in cytosol from the two cell lines. However, 2 binders in Ishikawa cells (Kd approx. 0.2 and 6 nM) could be detected by the FASA method; the higher affinity binder in HEC-50 cells could not be clearly demonstrated. Structural differences in the specific estrogen binders which might distinguish HEC-50 from Ishikawa cells or normal endometrial tissue were investigated by using the anti-ER monoclonal antibody JS 34/32. Interaction of the antibody with [3H]estradiol binders of estrogen-responsive cells and tissue was evident from the formation of labeled complexes that were shown to sediment faster in glycerol density gradients and could be immunoprecipitated with Protein A attached to Sepharose beads. In contrast, the antibody did not recognize labeled specific binders in the HEC-50 cells. Furthermore, [3H]estradiol receptors in Ishikawa cells could be transformed into a species that exhibited increased hydrophilicity, evident from its binding to DNA-cellulose, whereas binders from HEC-50 could not. These results indicate that the lack of responsiveness of HEC-50 cells to estrogens might be due to structural or functional alterations in the ER protein resulting in a loss of its capability to undergo estrogen-directed conformational changes required for biological activity.

Adenocarcinoma↗

PubMed1990

[EMG analysis of masticatory muscle fatigue and recovery rate during gum chewing].

An EMG computer analysis system was developed to analyze the mandibular function. The system enabled measurements of the masticatory muscle's rhythm, activity, and power spectrum for the same EMG burst during mastication. This study revealed that a power spectrum analysis was able to be carried out by a fast Fourier transform algorithm of the isometric contraction components of EMG bursts during mastication. The normal regulatory mechanism of the mandibular function was temporarily disturbed by clenching to inflict fatigue upon the masticatory muscles. EMG analysis of the masticatory muscles during gum chewing were observed before and immediately after clenching, and during their recovery periods. After fatigue induction, all of the masticatory rhythms of the masticatory muscles showed a decrease in EMG burst duration time (duration) and duration per cycle (D/C) that recovered with time. However, only the coefficient variation of the duration and D/C in the working side increased immediately after fatigue induction. The power spectrum shifted to a lower frequency immediately after fatigue induction, and recovered along with time. Furthermore, it was found that EMG activity influenced the power spectrum during gum chewing. In conclusion, this EMG analysis system may be used as a possible future diagnostic aid for mandibular dysfunction syndromes.

Chewing Gum↗

PubMed2003

Voice low tone to high tone ratio--a new index for nasal airway assessment.

There are several methodology based on voice analysis to evaluate nasal airway. Here we introduce a new quantitative index based on voice spectrum analysis to evaluate nasal obstruction. Ten subjects of nasal blockage were instructed to produced the sustained consonant-vowel syllable /m partial partial differential/ at comfortable levels of speech for at least 5 seconds. After nasal decongestant treatment, the second voice sample was collected. Sound spectrum was obtained by the algorithm of fast Fourier transform and the fundamental frequency (F0) was calculated by the method of autocorrelation. Voice low tone to high tone ratio (VLHR) was defined as the division of low frequency power (LFP) into high frequency power (HFP) of the sound power spectrum and was finally expressed in decibels. The cut-off frequency was the product of F0 and square root of (4 x 5). The VLHR after nasal decongestant treatment increased significantly as compared with that before treatment (P < 0.01). VLHR is a new index derived from sound spectral analysis and that may detect the changes in frequency characteristics of voice during treatment for nasal obstruction. The index is quantitative, non-invasive, and potentially useful for basic researches and clinical applications.

Adolescent↗

PubMed1997

Distribution mapping of ciliary beat frequencies of respiratory epithelium cells using image processing.

Through their rapid periodic actions, the cilia of the human respiratory tract play an important role in clearing inhaled noxious particles. An automated method is developed, based on an image-processing technique, to measure and analyse objectively and quantitatively, ciliary beat frequency (CBF). Microscopic ciliary images are transformed into digitised grey images through an image grabber inside a PC, and signals are extracted from these, based on an image-subtraction algorithm, and are processed through power spectrum analysis using a fast Fourier transform (FFT). By means of the FFT power spectrum, maximum peak frequencies are detected as CBFs in each partitioned block for the entire digitised field. Using these CBFs, distribution maps are composed in various resolutions, showing visually the spatial distribution of CBFs through cells and in a single cell. To measure CBF variations quantitatively, phenylephrine hydrochloride is used, and the changes in CBF influenced by its concentration and duration are observed.

Cell Culture Techniques↗

PubMed1995

Altered heart rate variability in panic disorder patients.

Resting electrocardiographic recordings were obtained from 10 patients with panic disorder (PD) and 14 normal controls. Signal analysis of the beat-to-beat heart rate variability was performed by means of power spectrum analysis. The analysis revealed that patients with PD had marked reduction in the high-frequency peaks of the power spectrum densities. An Energy Ratio Index (ERI), which accurately differentiated between patients and controls, was calculated. In PD patients, a significant correlation was demonstrated between the clinical ratings and the energy ratios. Our findings suggest that decreased heart rate variability may be a characteristic of PD. The importance of this finding as a diagnostic marker and the underlying pathophysiological mechanisms need to be further explored.

Adult↗

PubMed1983

Masseter muscle fatigue in man objectively quantified by analysis of myoelectric signals.

Localized muscle fatigue in the masseter muscle was studied with a method based on power spectrum analysis of myoelectric signals. Under the influence of fatiguing contractions, a gradual shift of the spectral curve occurred; the rate of change was taken as a measure of the development of fatigue. The fatigue was dependent on the bite force. The existence of a threshold value of force, below which significant myoelectric fatigue changes do not develop, was shown.

Adult↗

PubMed1999

Molecular weights of CTLA-4 and CD80 by sedimentation equilibrium ultracentrifugation.

Proteins that are heavily glycosylated pose unique challenges in their biophysical characterization. In particular, molecular weight analysis is exacerbated by such glycosylation. For example, glyoproteins are refractory to careful mass spectrum analysis and often give anomalous retention times using size exclusion chromatography. We combine several approaches to characterize the molecular weights of the extracellular domains of the glycoproteins CTLA-4 and CD80 using carbohydrate analysis, electrospray mass spectrometry, size exclusion chromatography, and analytical ultracentrifugation. In addition, we have applied a method described previously, using sedimentation equilibrium analysis to calculate the contribution of carbohydrates to the molecular masses of CTLA-4 and CD80. It is important to understand the oligomeric states of these protein domains because the interaction between these lymphocyte receptors plays an important costimulatory role in the Th-cell antigenic response. It is thought that extracellular interactions between these receptors may regulate both the self-association of these receptor proteins and the oligomeric state of the heterocomplex; this regulation has important consequences for potentiating the signaling mechanism between Th-cells and antigen-presenting cells.

Abatacept↗

PubMed1992

Arachidonic acid and prostaglandin E2 activate small-conductance Cl- channels in the basolateral membrane of rabbit parietal cells.

1. Cl- channels in the basolateral membrane of non-stimulated parietal cells in isolated rabbit gastric glands were studied by patch-clamp and noise analysis techniques. 2. Voltage-independent whole-cell currents were recorded from parietal cells equilibrated with Cl(-)-containing solutions. Upon reducing the Cl- concentration of the basolateral bathing solution, the current-voltage curve was rapidly shifted to the right. The reversal potential changed according to changes in the equilibrium potential for Cl-. 3. A Cl- channel blocker, 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB) inhibited whole-cell Cl- currents. The half-maximal inhibitory concentration of NPPB was 300 microM, and the inhibition was reversible (at less than or equal to 200 microM). Another Cl- channel blocker, 4-acetamido-4'-isothiocyanatostilbene-2,2'-dilsulphonic acid or diphenylamine-2-carboxylate was much less effective. 4. The power spectra of whole-cell Cl- current fluctuations contained one Lorentzian component. The single Cl- channel conductance was estimated to be 0.35 pS by the variance noise analysis, which is in agreement with the value obtained by a method of power spectrum analysis (0.29 pS). 5. The addition of arachidonic acid (10 microM) to the basolateral medium markedly increased the whole-cell Cl- current. The combined application of a cyclo-oxygenase inhibitor, indomethacin (50 microM), and a lipoxygenase inhibitor, esculetin (100 microM), increased the Cl- current, whereas the administration of a phospholipase A2 inhibitor, mepacrine (100 microM), significantly decreased the whole-cell Cl- current. 6. A sizeable increase in the whole-cell Cl- current was also induced by a metabolite of arachidonic acid, prostaglandin E2 (10 microM), but not by leukotriene B4 (5 microM) or D4 (10 microM). 7. The present study has shown that small-conductance Cl- channels are present in the basolateral membrane of rabbit parietal cells, and that the channel was functionally regulated by arachidonic acid and prostaglandin E2.

Animals↗

PubMed2006

Novel digitalis-like factor, marinobufotoxin, isolated from cultured Y-1 cells, and its hypertensive effect in rats.

Marinobufagenin and telecinobufagin have been identified as digitalis-like factors in mammals. In toads, marinobufagenin-related compounds, such as marinobufotoxin (MBT), have been isolated in some tissues but not in mammals, and its biological action has not been elucidated. Herein, we aimed to explore the possible production and/or secretion of MBT and the biological action in rats. First, the MBT in culture supernatant of the adrenocortical-originated cell line Y-1 was analyzed by high-performance liquid chromatography and sensitive ELISA for marinobufagenin-like immunoreactivity. Moreover, the structural information was obtained by mass spectrometry. To determine the biological action, MBT (9.6 and 0.96 microg/kg per day) was intraperitoneally infused via an osmotic minipump for 1 week. Blood pressure and renal excretion of marinobufagenin-like immunoreactivity were measured. Marinobufagenin-like immunoreactivity was found in Y-1 cell culture media, and the concentration increased until 24 hours. The structural analysis suggested that marinobufagenin-like immunoreactivities were marinobufagenin and MBT, and tandem mass spectrum analysis revealed them with the specific daughter ions. The highest sensitive ELISA-positive peak of marinobufagenin-like immunoreactivity in the media was MBT. Continuous administration of MBT in rats for 1 week significantly increased systolic blood pressure and renal excretion of marinobufagenin-like immunoreactivity compared with control rats (135+/-3.0 versus 126+/-2.0 mm Hg and 1.41+/-0.286 versus 0.34+/-0.064 ng/day, respectively). These data suggest that MBT, arginine-suberoyl ester of marinobufagenin, can be a novel digitalis-like factor with hypertensive action and is secreted from the adrenocortical cells.

Adrenal Cortex↗

PubMed1982

Developmental studies on EEG spectral analysis in mentally retarded children.

The EEG developmental characteristics of 36 mentally retarded infants were investigated by auto-power spectrum analysis. A significant positive correlation with age was found in the dominant frequency in all of the three regions, occipital, central, and frontal. A tendency for the generalized component to increase was found in 3- to 5-year-old subjects as compared with those aged 6 months to 1 year and 7 months. Developmental coherence characteristics could not be found. The peak components tended to show higher coherence values in the frontal-central relation than in the central-occipital and occipital-frontal ones.

Cerebral Cortex↗

PubMed1995

[Detecting blood pressure variation using spectral analysis in obstructive sleep apnea syndrome with and without nCPAP therapy].

The variation of blood pressure was investigated by power spectrum analysis in 12 patients with severe sleep apnea with and without nCPAP-therapy. In the baseline findings systolic and diastolic variation consisted of mainly two types of pressure oscillations: Swings of slow frequency (0-0.06 Hz) in tight association with the periodicity of breathing disorder and arousal and extensive respiratory pressure waves (0.2-0.5 Hz) due to the increased intrathoracic pressure changes during breathing efforts with partial or complete obstruction of the upper airway. In general systolic was higher than diastolic variation and the contribution of slow pressure oscillations was considerably bigger than that of respiratory waves. Sufficient nCPAP-therapy resulted in a decrease of the mean pressure and in a clear reduction of systolic and diastolic variation in which both types of pressure waves were diminished in a similar manner. At last there was a higher proportion of pressure waves in the frequency range of the Mayer-waves (0.06-0.2 Hz) with nCPAP-therapy.

Adult↗

PubMed1978

[The mathematical rationale for the clinical EEG-frequency-bands. 1. Factor analysis with EEG-power estimations for determining frequency bands].

In order to determine whether the clinically used frequency bands of the EEG can also be obtained by a mathematical system we did a factor analysis with 480 EEG recordings, 5 minutes each, in 60 healthy male volunteers. A power spectrum analysis was done and 57 frequency bands between 1.5 and 30.0 Hz in a half Hz steps were calculated. The factor structure obtained made the following frequency bands (Hz) reasonable: deltaF = 1.5 - 6.0, thetaF = 6.0 - 8.5, alpha1F = 8.5 - 10.5, alpha2F = 10.5 - 12.5, beta1F = 12.5 - 18.5, beta2F = 18.2 - 21.0, beta3F = 21.0 - 30.0. Except for alpha1F all other 6 frequency bands were represented by one general factor with the complexity 1. The variance of the alpha1F band is explained by several of the 6 factors. The clinically known and the by factor analysis obtained frequency bands in the beta-range are similar. The clinically alpha-band is subdivided into two frequency bands alpha1F and alpha2F by the factor analysis. The clinically known border line between delta- and theta-band of 3.5 Hz cannot be found by factor analysis.

Adult↗

PubMed1995

[P-NMR analysis of the hepatic cell energetic metabolism in tumor-bearing mice by moxibustion treatment].

The new technique, NMR (nuclear magnetic resonance) spectrum analysis was used in this research to measure the state of energetic metabolism of hepatic cells at the organic level. The experimental results demonstrated that moxibustion on Guanyuan (CV4) point could remarkably increase the ATP molecules in the hepatic cells, significantly raise the thermodynamic reserve and phosphate potential of the hepatic cells, so as to enhance the functional activities of liver. It is discussed here of the mechanism of anti-tumor by moxibustion treatment and of the theory of warming the kidney and enhancing the Yang to tonify to energetic Qi by moxibustion on Guanyuan point.

Animals↗

PubMed2002

Spectroscopic analysis of the autofluorescence from human bronchus using an ultraviolet laser diode.

A GaN based ultraviolet (UV) laser diode (LD) was used to study the autofluorescence (AF) spectrum of the normal and tumor human bronchial tissues under ex vivo conditions. The UV LD generates a coherent short wavelength (around 400 nm) light beam with an intensity of about a few watts. AF spectrum data can be obtained without interference by excitation light. A clear blue peak located at around 483 nm was observed along with a green peak at around 560 nm in the normal tissue. The peak intensities observed were very weak for the tumor tissues. The AF imaging and spectrum analysis were performed along with a histopathological study. The spatial distribution of the elastin in the bronchial tissue affected the intensity of the AF whereas the spectrum shape was not affected. Strong AF was observed from regions that include a high density of the elastin. Biopsy measurements were performed for ex vivo samples, and depth profiling of the elastin was studied along with variations of the AF spectrum. AF spectra excited by the UV LD for fluorescence materials including FAD, NADH, and elastin were measured. The spectrum shape of the elastin as well as of NADH was similar to that of normal bronchial tissues.

Bronchi↗