We consider a chaotic system with a double-scroll attractor proposed by Elwakil, composing with a second-order system, which has low-dimensional multiple invariant subspaces and multi-level on-off intermittency. This type of composite system always includes a skew-product structure and some invariant subspaces, which are associated with different levels of laminar phase. In order for the level of laminar phase be adjustable, we adopt a nonlinear function with saturation characteristic to tune the range of a certain state variable so that the number and position of the laminar phase level can be arbitrarily controlled. We find that there exist many interesting statistical characteristics in this complex system, such as the probability distribution of the laminar lengths with -3/2 exponent in the power law and random jumping of the system trajectories.
The aim of this study was to evaluate cell diversity by considering
how Ca2+ signaling has been adapted in skeletal muscle cell
function. We characterized single C2C12 myoblasts through
intracellular Ca2+ signaling kinetics after exposure to specific
drugs and calcium blockers using fast fluorescence
microspectrofluorimetry followed by ATP effect analysis, which
confirmed the expression of functional purinergic adenosine and
P2 receptors. Further, we found that glutamate sensitivity of
C2C12 cells was mediated by ionotropic glutamate receptors; on
the other hand, most cells were responsive to cyclopiazonic acid,
which inhibits the sarco-endoplasmic reticulum Ca2+-ATPase
pump. These results suggest that C2C12 cells possess functional
L- and P/Q-type voltage-operated Ca2+ channels, ryanodine
receptors and functional sarcoplasmic reticulum Ca2+ stores
(typical for muscle cells), adenosine and P2 purinergic receptors,
as well as ionotropic glutamate receptors. The evaluation of
intracellular Ca2+ signaling is a promising approach towards
a better understanding and control of the physiopathological
properties of myogenic cells that could be used as a predictive
factor in the selection of optimal cells for scaffold recellularization
or for tissue engineered constructs used in stem cell therapy.
Trichloroacetic acid (TCA), secondary air pollutant (SAP) and a product of photooxidation of volatile chlorinated C-i-hydrocarbons has phytotoxic properties and negatively influences on the state of forest health in general. The present knowledge shows the uptake of TCA by the spruce from the atmosphere by precipitation over soil, roots, and transpiration stream up into needles, where it effects the photosynthetic apparatus of the plant. To judge the role of TCA in forest ecosystems its effects along with other stressors must be followed. Those include, above all, emissions of sulphur oxides and fluoride from burning energetic coal. From monitoring the selected stressors - the content of total sulphur, fluorine and chlorine besides TCA - in spruce needles on selected stands, a positive correlation between the needle loss (as a measure of the spruce forest damage) and the content of S, F, and TCA was found. In this way the negative effect of TCA was conflrmed.
Solving inverted pendulum by co-simulation between multi-body solver MotionSolve and signal processing control in solidThinking Activate. The simulation of inverted pendulum uses an innovative model of friction which is physically and mathematically more accurate than usual CAE friction models. This model of friction adds nonlinearity to the system. Two types of controlling mechanism for active balancing of inverted pendulum are used: PID and ANN controller. A non-traditional false angular deviation approach for returning a cart to its initial position was used.
Clinical oncologists have been focusing their efforts on attempting to define risk groups of patients with unusual biological reactions to the recommended therapy regimens using molecular biology techniques. The aims of our study were: (i) to find a design and validate a method for fast and reliable analysis of the D1853N (5557G>A) genetic polymorphism in the ATM (ataxia-telangiectasia mutated) gene; (ii) to use side-directed mutagenesis to generate ATM 5557A-positive DNA (reference ATM5557A DNA); and (iii) to analyze a group of patients suffering from cervical carcinoma with adverse responses to radiotherapy. The 5557A variant was found in three of twenty women (15%). Our data show that the prevalence of the 5557A allelic variant in cervical cancer subjects with adverse responses after irradiation probably does not differ from the prevalence common in Caucasians. A larger population study should confirm these preliminary results., Martin Beránek, Monika Drastíková, Simona Paulíková, Igor Sirák, Milan Vošmik, Jiří Petera, and Literatura 31
a1_Using magnetic resonance imaging (MRI) in conjunction with synchronized spirometry we an alyzed and compared diaphragm movement during tidal breathing and voluntary movement of the diaphragm while breath holding. Breathing cycles of 16 healthy subjects were examined using a dynamic sequence (77 slices in sagittal plane during 20 s, 1NSA, 240x256, TR4.48, TE2.24, FA90, TSE1, FOV 328). The amplitude of movement of the apex and dorsal costophren ic angle of the diaphragm were measured for two test conditions: tidal breathing and voluntary breath holding. The maximal inferior and superior positions of the diaphragm were subtracted from the corresponding positions during voluntary movements while breath holding. The average amplitude of inferio-superior mo vement of the diaphragm apex during tidal breathing was 27.3±10.2 mm (mean ± SD), and during voluntary movement while breath holding was 32.5±16.2 mm. Movement of the costophrenic angle was 39±17.6 mm during tidal breathing and 45.5±21.2 mm during voluntary movement while breath holding. The inferior position of the diaphragm was lower in 11 of 16 subjects (68.75 %) and identical in 2 of 16 (12.5 %) subj ects during voluntary movement compared to the breath holding. Pearson’s correlation coefficient was used to demonstrate that movement of the costophrenic angle and apex of the diaphragm ha d a linear relationship in both examined situations (r=0.876). A correlation was found between the amplitude of diaphragm movement during tidal breathing and lung volume (r=0.876). The amplitude of movement of the diaphragm with or without breathing showed no correlation to each other (r=0.074). The moveme nt during tidal breathing shows a correlation with the changes in lung volumes. Dynamic MRI demonstrated that individuals are capable of moving their diaphragm voluntarily, but the amplitude of movement differs from person to person., a2_In this study, the movements of the diaphragm apex and the costophr enic angle were synchronous during voluntary movement of the diaphragm while breath holding. Although the sample is small, this study confirms that the function of the diaphragm is not only respiratory but also postural and can be voluntarily controlled., P. Kolář, J. Neuwirth, J. Šanda, V. Suchánek, Z. Svatá, J. Volejník, M. Pivec., and Obsahuje bibliografii
The physical properties of tidal gravimetric instruments allow recording, not only tidal effects, but also waves generated by earthquakes. Three gravimetric stations with determined transfer functions and co-located seismic stations from the observatories in Western and Central Europe were selected for analysis. The observatories are equipped with almost all types of sensors available on the market, which allow for thorough analysis of earthquake recordings in the period range of 10–1000 s. In total, over 10,000 traces of worldwide earthquakes were investigated. The saturation levels of gravimeters as well as a correlation between the gravimetric and seismometric signals of an earthquake were carefully analysed. A simple processing scheme of gravimetric signal of earthquakes was adopted thanks to the probabilistic power spectral density analysis of continuous recordings. The detail analysis of transfer function of gravimeters allowed to define a period range when a sensitivity coefficient (calibration factor) and a time lag value only can be used to properly describe the properties of instruments. What’s more, it has been shown based on the calculated group-velocity dispersion curves of fundamental mode of Rayleigh waves, that the Earth’s mantle structure can be determined for greater depths from the recording of tidal gravimeters than from typical broad-band seismometers.
In this study, a new approach based on the consideration that electroencephalogram (EEG) signals are chaotic signals was presented for automated diagnosis of electroencephalographic changes. This consideration was tested successfully using the nonlinear dynamics tools, like the computation of Lyapunov exponents. Multilayer perceptron neural network (MLPNN) architectures were formulated and used as basis for detection of electroencephalographic changes. Three types of EEG signals (EEG signals recorded from healthy volunteers with eyes open, epilepsy patients in the epileptogenic zone during a seizure-free interval, and epilepsy patients during epileptic seizures) were classified. The computed Lyapunov exponents of the EEG signals were used as inputs of the MLPNNs trained with backpropagation, delta-bar-delta, extended delta-bar-delta, quick propagation, and Levenberg-Marquardt algorithms. The performances of the MLPNN classifiers were evaluated in terms of training performance and classification accuracies. Receiver operating characteristic (ROC) curves were used to assess the performance of the detection process. The results confirmed that the proposed MLPNN trained with the Levenberg-Marquardt algorithm has potentiality in detecting the electroencephalographic changes.
Presented work concerns with a sensitivity analysis of a harmonically excited bending vibration of a rotating couple of blades with a friction element with regard to the parameters of the friction characteristic. Either of the blades is discretized by FEM using beam elements and continuously distributed weight is concentrated in nodal points. The friction in central contact points between blade shrouds and the friction element is approximated by a continuous function depending on slip velocities of the shrouds relative to the friction element. Considered friction characteristic respects the micro-slip phase at the very low slip velocities and the macro-slip (full-slip) phase at the higher slip velocities. The values of the friction characteristic parameters are identified by comparison of the numerical simulations of a transient vibration with experiments used in IT AS CR. and Obsahuje seznam literatury