Spectral characteristics of skin temperature indicate peripheral stress-response

High-resolution measurement of skin temperature in 11 normal subjects revealed low-amplitude temperature oscillations (40 x 10(-3) degrees C). The temperature signal measured on two hands during baseline, stress, and recovery periods, was filtered to separate the low-amplitude oscillations from the temperature signal. Spectral analysis of the filtered signal showed that most of the energy of the signal is in a range of 0.01 to 0.03 Hz. Frequency shifts and amplitude changes of the largest component were observed in response to mental stress. In subjects with high baseline values of either of these two variables, a decrease was observed in response to stress. An opposite response was observed in subjects with significantly lower baseline levels. Stress-related changes in peak frequency ranged from -25% to +18.2%; changes in peak amplitude ranged from -74.6% to +280%. Changes in the mean temperature were limited to 2.4%. Thus, the oscillatory component showed higher sensitivity to psychological stress than mean temperature. The spectrum of this component was compared to the spectrum of the blood pressure waves measured noninvasively. Both exhibited similar dynamics of energy, peak amplitude, and peak frequency in response to psychological stress. This similarity suggests that the oscillatory temperature component reflects stress-related changes of peripheral vasomotor activity.     

S-states of helium-like ions

A simple Mathematica (version 7) code for computing S-state energies and wave functions of two-electron (helium-like) ions is presented. The elegant technique derived from the classical papers of Pekeris (1958, 1959, 1962, 1965, 1971) [1], [2] and [3] is applied. The basis functions are composed of the Laguerre functions. The method is based on the perimetric coordinates and specific properties of the Laguerre polynomials. Direct solution of the generalized eigenvalues and eigenvectors problem is used, distinct from the Pekeris works. No special subroutines were used, only built-in objects supported by Mathematica. The accuracy of the results and computation times depend on the basis size. The ground state and the lowest triplet state energies can be computed with a precision of 12 and 14 significant figures, respectively. The accuracy of the higher excited states calculations is slightly worse. The resultant wave functions have a simple analytical form, that enables calculation of expectation values for arbitrary physical operators without any difficulties. Only three natural parameters are required in the input.The above Mathematica code is simpler than the earlier version (Liverts and Barnea, 2010 [4]). At the same time, it is faster and more accurate.

Program summary

Program title: TwoElAtomSL(SH)Catalogue identifier: AEHY_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEHY_v1_0.htmlProgram obtainable from: CPC Program Library, Queen?s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 11 434No. of bytes in distributed program, including test data, etc.: 540 063Distribution format: tar.gzProgramming language: Mathematica 7.0Computer: Any PCOperating system: Any which supports Mathematica; tested under Microsoft Windows XP and Linux SUSE 11.0RAM:?¹⁰⁹ bytesClassification: 2.1, 2.2, 2.7, 2.9Nature of problem: The Schrödinger equation for atoms (ions) with more than one electron has not been solved analytically. Approximate methods must be applied in order to obtain the wave functions or another physical attributes from quantum mechanical calculations.Solution method: The S-wave function is expanded into a triple set of basis functions which are composed of the exponentials combined with the Laguerre polynomials in the perimetric coordinates. Using specific properties of the Laguerre polynomials, solution of the two-electron Schrödinger equation reduces to solving the generalized eigenvalues and eigenvector problem for the proper Hamiltonian. The unknown exponential parameter is determined by means of minimization of the corresponding eigenvalue (energy).Restrictions: First, the too large length of expansion (basis size) takes the too large computation time and operative memory giving no perceptible improvement in accuracy. Second, the number of shells Ω in the wave function expansion enables one to calculate the excited nS-states up to n=Ω+1 inclusive.Running time: 2–60 minutes (depends on basis size and computer speed).     

Dewetting and microphase separation in symmetric polystyrene‐block‐polyisoprene diblock copolymer ultrathin films

The kinetics of surface structure evolution in ultrathin films of low‐molecular‐weight polystyrene‐block‐polyisoprene (M_w: 7300 g mol^?1–7300 g mol^?1) diblock copolymer at temperatures below the bulk order‐to‐disorder transition temperature are presented. Films with two different thicknesses were studied as a function of annealing temperature using atomic force microscopy. These film thicknesses enabled the investigation of the competition between microphase separation and dewetting that resulted in two different morphologies: long‐range bicontinuous structures and random holes. Three distinctive stages of structure evolution were observed in bicontinuous structure, with the underlying mechanism compared with spinodal dewetting. Thicker films presented holes on their surfaces upon annealing at elevated temperatures, and kinetics of formation of the holes were discussed. We found that the molecular mobility determined the rates of dewetting, while the microphase separation hardly affected the dewetting process. © 2015 Society of Chemical Industry     

Evaluation of center-line extraction algorithms in quantitative coronary angiography

Objective testing of centerline extraction accuracy in quantitative coronary angiography (QCA) algorithms is a very difficult task. Standard tools for this task are not yet available. We present a simulation tool that generates synthetic angiographic images of a single coronary artery with predetermined centerline and diameter function. This simulation tool was used creating a library of images for the objective comparison and evaluation of QCA algorithms. This technique also provides the means for understanding the relationship between the algorithms' performance and limitations and the vessel's geometrical parameters. In this paper, two algorithms are evaluated and the results are presented.     

A new method for estimation of the left ventricular pressure-volumearea

We present a new method for obtaining the pressure-volume area (PVA) as defined by Suga. The method allows calculation of the PVA from pressure and flow waveforms of ejecting beats and requires only one isovolumic ventricular contraction performed at any end diastolic volume.     

Brain potentials from dyslexic children recorded during short-term memory tasks

Event Related Potentials (ERPs) from thirty children (9-13 years old); fourteen of whom were dyslexic and sixteen normal-reading controls, were recorded during the performance of a memory scanning task. Visually presented stimuli consisted of either digits (lexical) or unfamiliar (non-lexical) characters. The subjects had to indicate whether a probe stimulus was a member of a preceding memorized set, or not. The memorized sets included 1, 2 or 3 items. Performance accuracies were significantly lower and reaction times longer in the dyslexic group. The significant Group x Lexicality interaction demonstrated P3 amplitudes which were smaller to lexical compared to non-lexical stimuli in dyslexics compared to skilled readers. Brain activity in response to the probes was more prominent over the right scalp in dyslexics, in contrast to controls that had left side prominence. The results suggest that dyslexic children relate to the physical features of stimuli as opposed to skilled readers, who rely more on the linguistic features of the stimuli. We suggest that remembering visually presented items in dyslexics involves different cognitive strategies and brain structures compared to skilled readers.     

Sympathetic nervous system activity in stress and biofeedback relaxation

This article describes several studies on the measurement of slow rhythms in the heart and in peripheral vasculature and their relationship to stress and relaxation. These studies are preliminary steps in an attempt to quantify stress and relaxation. Mental stress is a major, well-documented factor in the development of cardiovascular diseases; relaxation, however, is perceived as the opposite state, which, presumably, can negate these harmful effects. To compare the effects of stress-management or relaxation techniques, stress and relaxation must be first quantified. Three methods for quantifying sympathetic activity as an indicator of stress were analyzed. These are heart-rate variability (HRV), photoplethysmographic measurement of peripheral vasomotor activity, and a novel measurement of skin temperature variability. The study showed that due to "low pass filtering response" of the thermal-transfer function between the blood vessel and the skin's temperature, the temperature-variability measurement is minimally sensitive to mechanical factors or accidental noise. Therefore, the temperature variability could be useful for the continuous tracking of vascular activity and its sympathetic tone. Tracking changes in the pressure-wave envelope (PV) provides another alternative for studying sympathetic nervous system (SNS) effects on peripheral vasculature. A drastic reduction in PV and a loss of correlation between temperature variability on the left and right hand confirm the predominant role of SNS in mediating these signals. Functional responses of these signals to SNS-stimulating (mental stress) or blocking (biofeedback) maneuvers are perturbed in patients with CAD (coronary artery disease), suggesting that these tests could be used as simple diagnostic or screening tools.     

Increase in the frequency of certain diseases (bronchitis, pneumonia, ent diseases and conjunctivitis) in workers as compared with housewives, in a location polluted by the burning of coal]

The growth kinetics of human diploid skin fibroblasts derived from cystic fibrosis (CF) homozygotes, CF heterozygotes and normal individuals was determined. The population doubling times increased with time in culture, and no difference was observed between the 3 genotypes tested. The cell cycle times remained constant through the 10th subculture, while the growth fraction, or fraction of cells in the cell cycle, decreased with culture time; however, changes in the growth fraction and population doubling time appear to be related to cellular senescence in vitro rather than to cystic fibrosis.     

Film thickness in horizontal annular flow

Film thickness in horizontal annular flow in small diameter pipes (8-12 mm) was measured as a function of circumferential position. In addition a simple analytical model for the prediction of the film thickness at the top and bottom of the pipe is proposed.