Significant correlations between certain spectra of atmospherics and different biological and pathological parameters

Atmospherics are very short naturally occurring electromagnetic impulses of between 4 and 50 kHz. In this review we summarize our results concerning the correlations between certain spectra of atmospherics and several biological and pathological parameters.Paper presented at the 12th International Congress of Biometerology (Vienna 1990)     

Middle and Late Permian stratigraphic correlations on the Russian Platform: significance of ostracodes

During the International Peri-Tethys Program, the realization of the maps required efficient correlation tools. During the Late Paleozoic and particularly during the Wordian (Middle Permian), the Russian Platform was under continental and/or marginal paleoenvironmental conditions. This paper draws up the synthesis of the ostracode species recognized in the Middle-Late Permian in this area, from the Barents Sea up to the Precaspian Depression, and shows their importance as a stratigraphic tool for the correlations of continental series.     

The selectivity of noise and coupling for coherence biresonance and array-enhanced coherence biresonance in coupled neural systems

The selectivity of noise and coupling for coherence biresonance (CBR) and array-enhanced coherence biresonance (AECBR) in coupled neural systems has been investigated. It is shown that, depending on the coupling strength and noise intensity, various coherence behaviors and phenomena are exhibited, including CBR, coherence resonance without tuning, AECBR and undamped signal transmission. There exist optimal coupling and noise regions for the occurrence of CBR and AECBR in the transmission of noise-induced oscillations (NIOs).     

Cardioviral RNA structure logo analysis: entropy, correlations, and prediction

In recent years, there has been an increased number of sequenced RNAs leading to the development of new RNA databases. Thus, predicting RNA structure from multiple alignments is an important issue to understand its function. Since RNA secondary structures are often conserved in evolution, developing methods to identify covariate sites in an alignment can be essential for discovering structural elements. Structure Logo is a technique established on the basis of entropy and mutual information measured to analyze RNA sequences from an alignment. We proposed an efficient Structure Logo approach to analyze conservations and correlations in a set of Cardioviral RNA sequences. The entropy and mutual information content were measured to examine the conservations and correlations, respectively. The conserved secondary structure motifs were predicted on the basis of the conservation and correlation analyses. Our predictive motifs were similar to the ones observed in the viral RNA structure database, and the correlations between bases also corresponded to the secondary structure in the database.     

Significant correlations between certain spectra of atmospherics and daily periodic activities of Mongolian gerbils (Meriones unguiculatus L.)

We describe significant correlations between 10 and 28 kHz atmospherics (according to Baumer) and the running activities of ten Mongolian gerbils (Meriones unguiculatus L.) depending on their circadian rhythm over a 42-day period (August/September 1988).     

Demonstration of correlations between the 8 and 10 kHz atmospherics and the inflammatory reaction of rats after carrageenan injection

Between the mean daily density of 28 kHz atmospherics and the onset of epileptic fits there is a highly significant correlation coefficient (r) of 0.30; there is a negative coefficient of –0.20 between the fits and the mean daily density of 10 kHz atmospherics. The onset of heart infarction is correlated with 28 kHz atmospherics (r=0.15). Furthermore, we have discovered that sudden deafness is also correlated with certain configurations of atmospherics. In this paper we report the following correlation coefficients between the inflammatory reaction of rats to a carrageenan injection (rci) into a hind paw and the mean daily pulse rate of atmospherics of the same day:r=0.49 for the 8 kHz atmospherics (P<0.02) andr=0.44 for the 10 kHz atmospherics (P<0.04). The correlations between rci reaction and other atmospherics (12 and 28 kHz) are smaller and not significant. By the method of multiple linear regression we found a multipleR=0.54 between rci reaction and the 8 and 10 kHz atmospherics (the regression function for the rci reaction is 0.15+0.004×8 kHz+0.002×10 kHz,P<0.05).     

脑电图与早产儿脑损害的相关性研究

脑电图（Electroencephalography EEG）是观察早产儿（premature infants）脑损害的敏感方法。急性和慢性EEG的改变与早产儿以后的神经和认知功能异常有相关性,应用神经生理学的方法诊断早产儿脑损害,早期持续在ICU病房的EEG监测和在以后阶段的EEG检查相结合是比较理想的手段。     

The significance threshold for coherence when using the Welch's periodogram method: Effect of overlapping segments

A classical tool to identify coupling mechanisms between two biological signals is transfer function (TF) analysis, commonly estimated by the Welch's periodogram method. However, the reliability of TF estimation depends on the coherence function, an index of linear coupling in the frequency domain. Thus, a threshold value has to be determined before assuming a coupling between two signals at a given frequency.Koopmans (The spectral analysis of time series) proposed a theoretical expression in the case of non-overlapping segments. Overlapping segments, however, improves the estimation of TF.In the present study, a modification of the expression by Koopmans is proposed for taking into account the effect of the overlapping procedure, including the most common case of a 50% overlapping ratio. Simulation tests were done on non-coherent signals (using the Hanning window), and a Kolmogorov–Smirnov test was used to check for the adequacy with the proposed threshold formula. The results showed that for an overlapping ratio of 50%, no statistical difference could be found (P > 0.05), except when using less than seven segments.The method has been applied to the computation of the transfer function between systolic blood pressure and heart rate.     

Early diagnostic value of optical coherence tomography in the clinical prediction model for optic nerve injury in saddle space occupying patients

In this study, 50 patients with anterior ischemic optic neuropathy due to saddle block were selected as the experimental group, and 50 healthy subjects were used as the control group to conduct a study. The best corrected visual acuity examination, optical coherence tomography and visual evoked potential examination were performed on the two groups. The results of the study showed that the majority of patients were middle-aged and older people over the age of 50, but the youngest patients were only 37 years old. After various examinations, it was found that patients with optic nerve injury had a significant reduction in the best corrected visual acuity compared with healthy people. After the onset of the disease, the optic nerve fiber layer will first increase and then decline. During the course of the disease, the patient's optic nerve fiber layer will gradually thin to a much lower level than healthy people. And in comparing the thickness of the optic nerve fiber layer in patients with systemic disease and no systemic disease, it is found that the degree of optic nerve damage is more serious in patients with systemic diseases. After the VEP examination, the difference between the P100 wave latency and the N75-P100 amplitude of the diseased eye and the unaffected eye was statistically significant. Moreover, the difference between the patient's diseased eye and the healthy human eye is almost the same as that of the unaffected eye.     

Evaluation of oral mucosa collagen condition with cross‐polarization optical coherence tomography

The goal of the research was analysis of the effect of collagen condition in formation of cross‐polarized CP OCT images. We used of the CP OCT technique for studying collagen condition on an example of oral mucosa. Special histologic picrosirius red (PSR) staining of cheek mucosa specimens was used with subsequent assessing of the result of collagen staining in polarized light. High correlation (r = 0.692, p = 0.0001) between OCT signal standard deviation (SD) in cross‐polarized images and brightness of PSR stained collagen fibers in cheek mucosa specimens was demonstrated in patients with inflammatory intestine and oral mucosa diseases. We have found that the OCT signal SD in cross‐polarized images reflects two boundary conditions of collagen disorganization, namely, loss of fiber properties at active inflammation which attenuates the signal and fibrosis that occurs due to synthesis of a new remodeled collagen which amplifies the OCT signal. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Assesment of apoptosis induced changes in scattering using optical coherence tomography

The aim of this study is to identify changes in scattering with optical coherence tomography (OCT) and relate these measurements with mitochondrial changes during the initiation of apoptosis. Human retinal pigment epithelial cells were cultured and apoptosis was induced using 10% alcohol. Using the attenuation coefficient and backscattering, changes were measured during cell death in a cell‐pellet and monolayer respectively. To confirm apoptosis, fluorescent activated cell sorting was used. Mitochondrial activity during apoptosis was assessed using an oxidative stress assay and fluorescent confocal microscopy. Pelleted apoptotic cells measured with OCT showed a clear rise while untreated cells showed a very small increase in attenuation coefficient. Monolayered apoptotic cells displayed a distinct increase, while untreated cells showed a small increase in the backscattering. Apoptosis was confirmed by FACS experiments. Mitochondrial changes during the onset of apoptosis were also measured. The results demonstrate that apoptotic cell death could be monitored in real‐time by OCT. Changes in the scattering after induction of apoptosis are likely to be related to changes in the intracellular morphology. Oxidative stress‐induced mitochondrial swelling could be responsible for the initial increase, while cell blebbing and secondary necrosis subsequently for the observed decrease in scattering.

     

Temporal changes of mechanical signals and extracellular composition in human intervertebral disc during degenerative progression

In this study, a three-dimensional finite element model was used to investigate the changes in tissue composition and mechanical signals within human lumbar intervertebral disc during the degenerative progression. This model was developed based on the cell-activity coupled mechano-electrochemical mixture theory. The disc degeneration was simulated by lowering nutrition levels at disc boundaries, and the temporal and spatial distributions of the fixed charge density, water content, fluid pressure, Von Mises stress, and disc deformation were analyzed. Results showed that fixed charge density, fluid pressure, and water content decreased significantly in the nucleus pulposus (NP) and the inner to middle annulus fibrosus (AF) regions of the degenerative disc. It was found that, with degenerative progression, the Von Mises stress (relative to that at healthy state) increased within the disc, with a larger increase in the outer AF region. Both the disc volume and height decreased with the degenerative progression. The predicted results of fluid pressure change in the NP were consistent with experimental findings in the literature. The knowledge of the variations of temporal and spatial distributions of composition and mechanical signals within the human IVDs provide a better understanding of the progression of disc degeneration.     

Equilibrium theory and paleoecology

Although several paleontologists have recently attempted to apply MacArthur & Wilson's equilibrium theory to the fossil record, their efforts have not met with overwhelming success. The major difficulties have involved the use of questionable methodologies and the application of a fundamentally inappropriate theoretical base. In the first category it appears as if previous methods of data collection and their subsequent analyses must be critically reviewed in order to adequately test the equilibrium theory. Thus detailed species lists that include population numbers must be compiled for spatially restricted habitats. Sampling of local stratigraphic sections must be carried out on a centimeter by centimeter basis rather than at meter intervals. It appears most likely that the use of colonization curves, coupled with a determination of species saturation levels, will provide a rigorous, quantitative technique for the analysis of equilibrium states. It has become obvious over the past ten years that paleoecologists need to be more critical in their application of ecological theories to the fossil record and in substantiation of this claim, and contrary to earlier reports, it seems as if a valid test of the equilibrium theory in the fossil record has yet to be made.     

Wright's shifting balance theory and the diversification of aposematic signals

Despite accumulating evidence for selection within natural systems, the importance of random genetic drift opposing Wright's and Fisher's views of evolution continue to be a subject of controversy. The geographical diversification of aposematic signals appears to be a suitable system to assess the factors involved in the process of adaptation since both theories were independently proposed to explain this phenomenon. In the present study, the effects of drift and selection were assessed from population genetics and predation experiments on poison-dart frogs, Ranitomaya imitator, of Northern Peru. We specifically focus on the transient zone between two distinct aposematic signals. In contrast to regions where high predation maintains a monomorphic aposematic signal, the transient zones are characterized by lowered selection and a high phenotypic diversity. As a result, the diversification of phenotypes may occur via genetic drift without a significant loss of fitness. These new phenotypes may then colonize alternative habitats if successfully recognized and avoided by predators. This study highlights the interplay between drift and selection as determinant processes in the adaptive diversification of aposematic signals. Results are consistent with the expectations of the Wright's shifting balance theory and represent, to our knowledge, the first empirical demonstration of this highly contested theory in a natural system.     

Linear correlation between fractal dimension of EEG signal and handgrip force

Fractal dimension (FD) has been proved useful in quantifying the complexity of dynamical signals in biology and medicine. In this study, we measured FDs of human electroencephalographic (EEG) signals at different levels of handgrip forces. EEG signals were recorded from five major motor-related cortical areas in eight normal healthy subjects. FDs were calculated using three different methods. The three physiological periods of handgrip (command preparation, movement and holding periods) were analyzed and compared. The results showed that FDs of the EEG signals during the movement and holding periods increased linearly with handgrip force, whereas FD during the preparation period had no correlation with force. The results also demonstrated that one method (Katz’s) gave greater changes in FD, and thus, had more power in capturing the dynamic changes in the signal. The linear increase of FD, together with results from other EEG and neuroimaging studies, suggest that under normal conditions the brain recruits motor neurons at a linear progress when increasing the force.     

Evaluating strategies of phylogenetic analyses by the coherence of their results

I propose an approach to identify, among several strategies of phylogenetic analysis, those producing the most accurate results. This approach is based on the hypothesis that the more a result is reproduced from independent data, the more it reflects the historical signal common to the analysed data. Under this hypothesis, the capacity of an analytical strategy to extract historical signal should correlate positively with the coherence of the obtained results. I apply this approach to a series of analyses on empirical data, basing the coherence measure on the Robinson–Foulds distances between the obtained trees. At first approximation, the analytical strategies most suitable for the data produce the most coherent results. However, risks of false positives and false negatives are identified, which are difficult to rule out.     

Quantification of phase coupling and information transfer between electroencephalographic (EEG) signals: Analysis strategies,models and simulations

Different types of phase coupling between and within EEG signals are theoretically explained and coupling-related analysis strategies are reported. Effects of synchronization have been distinguished from effects signal transfer (propagation), where both are designated by a phase coupling. Six examples of phase coupling analysis are presented. The EEG data are derived from our previous investigations and analysis results are complemented by modelling and simulation studies.     

High-density EEG Recordings of the Freely Moving Mice using Polyimide-based Microelectrode

Electroencephalogram (EEG) indicates the averaged electrical activity of the neuronal populations on a large-scale level. It is widely utilized as a noninvasive brain monitoring tool in cognitive neuroscience as well as a diagnostic tool for epilepsy and sleep disorders in neurology. However, the underlying mechanism of EEG rhythm generation is still under the veil. Recently introduced polyimide-based microelectrode (PBM-array) for high resolution mouse EEG¹ is one of the trials to answer the neurophysiological questions on EEG signals based on a rich genetic resource that the mouse model contains for the analysis of complex EEG generation process. This application of nanofabricated PBM-array to mouse skull is an efficient tool for collecting large-scale brain activity of transgenic mice and accommodates to identify the neural correlates to certain EEG rhythms in conjunction with behavior. However its ultra-thin thickness and bifurcated structure cause a trouble in handling and implantation of PBM-array. In the presented video, the preparation and surgery steps for the implantation of PBM-array on a mouse skull are described step by step. Handling and surgery tips to help researchers succeed in implantation are also provided.