Increase In Relative Amplitude Research Articles

Blunted rest-activity rhythm is associated with increased white blood-cell-based inflammatory markers in adults: an analysis from NHANES 2011-2014

ABSTRACT Circadian rhythm disruption is associated with immune system disturbance and has been observed in many health problems where chronic-inflammation acts as a major contributor. We aim to examine whether rest-activity circadian rhythm is associated with chronic inflammation using white blood-cell-based inflammatory indices including white blood cell (WBC) count, neutrophil count, neutrophil-to-lymphocyte ratio (NLR) and systemic immune-inflammation index (SII). We analyzed the data from 8089 adults (age≥20) with at least 4 days of validated accelerometer recordings and a valid WBC count from the National Health and Nutrition Examination Survey (NHANES) 2011–2014. Non-parametric rest-activity circadian rhythm parameters were derived from the accelerometer recordings. In the models adjusting multiple covariates, a one-quantile increase in relative amplitude (i.e. more robust circadian rhythm) was associated with 1 × 108 cells/L decrease in WBC number (95% CI: 5 × 107 to 1.5 × 108, P < .001), 7 × 107 cells/L decrease in neutrophils (95% CI: 3 × 107 to 1.1 × 108, P = .003) and 15.2 × 109 /L decrease in SII (95% CI: 6 × 109 /L to 20 × 109/L, P = .019). Consistent results were also observed for the association of M10 value and L5 value with these inflammatory indices. Our results indicated that blunted rest-activity circadian rhythm is associated with increased white blood-cell-based inflammatory indices in adults, suggesting interventions aiming at enhancing circadian rhythm by lifestyle programs may be a novel approach to improve the general health.

Rest-activity circadian rhythm and impaired glucose tolerance in adults: an analysis of NHANES 2011-2014.

IntroductionCircadian rhythm disturbance occurs in type 2 diabetes, yet it is unknown whether it also exists in the prediagnostic phase of the disease. Thus, we examined the association of rest-activity circadian rhythm with 2-hour glucose levels and the risk of impaired glucose tolerance (IGT) in a nationally representative sample of adults without diabetes using a cross-sectional design.Research design and methodsWe analyzed data from 2760 adults without diabetes (age ≥20) with at least 4 days of validated accelerometer recordings and a valid oral glucose tolerance test from the National Health and Nutrition Examination Survey 2011–2014. Non-parametric rest-activity circadian rhythm parameters were derived from the accelerometer recordings.ResultsIn the models adjusting for multiple covariates, a one-quantile increase in relative amplitude (ie, increased circadian rhythmicity) was associated with 2.66 mg/dL decrease in 2-hour glucose level (95% CI −3.94 to −1.38, p<0.001) and a decreased odds of IGT (OR 0.75, 95% CI 0.63 to 0.89, p=0.002). A one-quantile increase in intradaily variability (ie, increased rhythm fragmentation) was associated with 3.01 mg/dL increase in 2-hour glucose level (95% CI 1.52 to 4.49, p=0.001) and an increased odds of IGT (OR 1.37, 95% CI 1.19 to 1.58, p<0.001).ConclusionsCircadian disruption is significantly associated with impaired glucose homeostasis in a general population of adults without diabetes. The association of circadian rhythm abnormalities with indicators of the pre-diabetic state suggests that circadian dysfunction may contribute to early disease pathogenesis.

The oscillatory effects of rhythmic median nerve stimulation

Entrainment of brain oscillations can be achieved using rhythmic non-invasive brain stimulation, and stimulation of the motor cortex at a frequency associated with sensorimotor inhibition can impair motor responses. Despite the potential for therapeutic application, these techniques do not lend themselves to use outside of a clinical setting. Here, the aim was to investigate whether rhythmic median nerve stimulation (MNS) could be used to entrain oscillations related to sensorimotor inhibition. MEG data were recorded from 20 participants during 400 trials, where for each trial 10 pulses of MNS were delivered either rhythmically or arrhythmically at 12 or 20 Hz. Our results demonstrate a frequency specific increase in relative amplitude in the contralateral somatosensory cortex during rhythmic but not arrhythmic stimulation. This was coupled with an increase in inter-trial phase coherence at the same frequency, suggesting that the oscillations synchronised with the pulses of MNS. The results show that 12 and 20 Hz rhythmic peripheral nerve stimulation can produce entrainment. Rhythmic MNS resulted in synchronous firing of neuronal populations within the contralateral somatosensory cortex meaning these neurons were engaged in processing of the afferent input. Therefore, MNS could prove therapeutically useful in disorders associated with hyperexcitability within the sensorimotor cortices.

Electrogastrography in Autonomous Vehicles-An Objective Method for Assessment of Motion Sickness in Simulated Driving Environments.

Autonomous vehicles are expected to take complete control of the driving process, enabling the former drivers to act as passengers only. This could lead to increased sickness as they can be engaged in tasks other than driving. Adopting different sickness mitigation techniques gives us unique types of motion sickness in autonomous vehicles to be studied. In this paper, we report on a study where we explored the possibilities of assessing motion sickness with electrogastrography (EGG), a non-invasive method used to measure the myoelectric activity of the stomach, and its potential usage in autonomous vehicles (AVs). The study was conducted in a high-fidelity driving simulator with a virtual reality (VR) headset. There separate EGG measurements were performed: before, during and after the driving AV simulation video in VR. During the driving, the participants encountered two driving environments: a straight and less dynamic highway road and a highly dynamic and curvy countryside road. The EGG signal was recorded with a proprietary 3-channel recording device and Ag/AgCl cutaneous electrodes. In addition, participants were asked to signalize whenever they felt uncomfortable and nauseated by pressing a special button. After the drive they completed also the Simulator Sickness Questionnaire (SSQ) and reported on their overall subjective perception of sickness symptoms. The EGG results showed a significant increase of the dominant frequency (DF) and the percentage of the high power spectrum density (FSD) as well as a significant decrease of the power spectrum density Crest factor (CF) during the AV simulation. The vast majority of participants reported nausea during more dynamic conditions, accompanied by an increase in the amplitude and the RMS value of EGG. Reported nausea occurred simultaneously with the increase in EGG amplitude. Based on the results, we conclude that EGG could be used for assessment of motion sickness in autonomous vehicles. DF, CF and FSD can be used as overall sickness indicators, while the relative increase in amplitude of EGG signal and duration of that increase can be used as short-term sickness indicators where the driving environment may affect the driver.

Focusing Sound Waves Using a Two-Dimensional Non-Linear System

Sound can be focused through a non-linear acoustic lens to produce high-energy waves capable of a variety of applications, such as eradicating cancer cells. Our previous research focused sound using a primitive system incapable of precise and predictable targeting. We engineered and assembled an improved device for focusing longitudinal waves that consisted of a non-linear acoustic lens, a release system, and a microphone recording array for data collection. During experimental trials the non-linear acoustic lens had a force applied to each of the 11 chains depending on the chain number from the desired focal point. Central trials focused sound waves to a calculated focal point to the center of the lens, while right side trials focused sound waves to the right side of the lens. The relative sound amplitude was recorded using a microphone array, analyzed, and averaged using sound analysis software. The average relative amplitudes of the control data compared to the experimental data at the predicted focal points were examined using a two-tailed t-test and were significantly different. This research was considered a success because the non-linear acoustic lens produced an evident increase in relative amplitude at a specific focal point in both sets of experimental trials.

Pre‐inspiratory and inspiratory hypoglossal motor output during hypoxia induced plasticity in the rat

Respiratory discharge in the hypoglossal (XII) nerve is composed of pre‐inspiratory (pre‐I) and inspiratory (I) activity. Our first purpose was to test the hypothesis that hypoxia‐induced plasticity in XII motor output is differentially expressed in pre‐I vs. I XII bursting. Short‐term potentiation (STP) of XII motor output was induced in vagotomized and ventilated rats by isocapnic hypoxia. Both pre‐I and I XII discharge abruptly increased at beginning of hypoxia, and the relative increase in amplitude was much greater for pre‐I vs. I bursting. In addition, STP was expressed in I but not pre‐I bursting following hypoxia. Specifically, I activity remained elevated following hypoxia but pre‐I bursting abruptly returned to pre‐hypoxia levels. Our second purpose was to test the hypothesis that STP of I XII activity results from recruitment of silent XII motoneurons (MNs) vs. rate coding of active MNs. Single fiber recordings were used to classify XII MNs as I, expiratory‐inspiratory (E‐I), or silent based on baseline discharge patterns. STP of I XII activity following hypoxia was associated with increased discharge frequency in active I and silent MNs, but not E‐I MNs. We conclude that the expression of respiratory plasticity is differentially regulated between pre‐I and I XII activity. Moreover, both recruitment of silent MNs and rate coding of active I MNs contribute to STP of XII motor output following hypoxia.

Preinspiratory and inspiratory hypoglossal motor output during hypoxia-induced plasticity in the rat

Respiratory-related discharge in the hypoglossal (XII) nerve is composed of preinspiratory (pre-I) and inspiratory (I) activity. Our first purpose was to test the hypothesis that hypoxia-induced plasticity in XII motor output is differentially expressed in pre-I vs. I XII bursting. Short-term potentiation (STP) of XII motor output was induced in urethane-anesthetized, vagotomized, and ventilated rats by exposure to isocapnic hypoxia (PaO2 of approximately 35 Torr). Both pre-I and I XII discharge abruptly increased at beginning of hypoxia (i.e., acute hypoxic response), and the relative increase in amplitude was much greater for pre-I (507+/-46% baseline) vs. I bursting (257+/-16% baseline; P<0.01). In addition, STP was expressed in I but not pre-I bursting following hypoxia. Specifically, I activity remained elevated following termination of hypoxia but pre-I bursting abruptly returned to prehypoxia levels. Our second purpose was to test the hypothesis that STP of I XII activity results from recruitment of inactive or "silent" XII motoneurons (MNs) vs. rate coding of active MNs. Single fiber recordings were used to classify XII MNs as I, expiratory-inspiratory, or silent based on baseline discharge patterns. STP of I XII activity following hypoxia was associated with increased discharge frequency in active I and silent MNs but not expiratory-inspiratory MNs. We conclude that the expression of respiratory plasticity is differentially regulated between pre-I and I XII activity. In addition, both recruitment of silent MNs and rate coding of active I MNs contribute to increases in XII motor output following hypoxia.

EEG factorial structure in pre-adolescents and young children

Event Abstract Back to Event EEG factorial structure in pre-adolescents and young children Carlos M. Gomez1*, Catarina Paulino1, Angelica Flores1 and Elena I. Rodriguez1 1 University of Sevilla, Fac. Psicologia, Spain The brain rhythms are defined by frequency, topography and psychological reactivity. In general there is agreement that such rhytms can be classified as, delta, theta, alpha, mu, beta and gamma rhythms upon these criteria. Children also show this general pattern, but there are some topographical and frequency changes with respect to adults. One possible way to define rhythms in a more quantitative way would be to explore data by means of factorial analysis and look for a separation of different frequencies. 48 subjects, 24 children (7-13 years) and 24 young adults (10-23) were recorded for a period of 3 minutes during spontaneous EEG activity. The power spectral density function was obtained for these recordings. Factorial analysis and mixed-model ANOVA (children and young adults as inter-subjects, and bands (delta, Theta, alpha and beta) and electrodes as whithin –subjects factors was computed. These analysis were performed on normalized and non-normalized spectral power. The ANOVA analysis showed that absolute frequency spectra of children presented a higher amplitude than those of young adults. The decrease of absolute amplitude with age was accompanied by an increase of relative amplitude in the beta band, indicating a shifting of spectrum to high frequency bands in adults with respect to young adults. The factorial analysis showed that delta, theta, alpha and beta bands can be segregated with three factors which explained more of the 80% of data variability. The factorial analysis was able to separate these bands in a quantitative manner in both groups. The present results suggested that frequency bands which have been defined by categorical criteria can also be defined quantitatively by factorial analysis. Moreover, the structure of EEG bands of the spontaneous EEG is already present in preadolescents children, with subtle differences in frequency, and high differences in absolute amplitude between both groups. Conference: 41st European Brain and Behaviour Society Meeting, Rhodes Island, Greece, 13 Sep - 18 Sep, 2009. Presentation Type: Poster Presentation Topic: Poster presentations Citation: Gomez CM, Paulino C, Flores A and Rodriguez EI (2009). EEG factorial structure in pre-adolescents and young children. Conference Abstract: 41st European Brain and Behaviour Society Meeting. doi: 10.3389/conf.neuro.08.2009.09.165 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 09 Jun 2009; Published Online: 09 Jun 2009. * Correspondence: Carlos M Gomez, University of Sevilla, Fac. Psicologia, Seville, Spain, cgomez@us.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Carlos M Gomez Catarina Paulino Angelica Flores Elena I Rodriguez Google Carlos M Gomez Catarina Paulino Angelica Flores Elena I Rodriguez Google Scholar Carlos M Gomez Catarina Paulino Angelica Flores Elena I Rodriguez PubMed Carlos M Gomez Catarina Paulino Angelica Flores Elena I Rodriguez Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

The influence of luminance on the multifocal ERG

To assess the efficacy of high luminance in increasing the amplitude of the multifocal electroretinogram (mfERG). We examined 5 male and 5 female volunteers in the age of 22-52 years (median 28 years). Three different stimulus luminance levels were applied: the bright areas of the stimulus pattern were set to 150, 300 and 500 cd/m(2). We recorded the potentials via DTL electrodes using the VERIS Science 4.4 system with 61 hexagons, pupils were dilated. Analysis was based on the 5 ring averages. Across all hexagons and subjects, the response density (approximately amplitude) rose by 20% when increasing the luminance by a factor of 3.3. The peak times decreased slightly with higher luminance, by less then 1.5 ms. Combining the present results with those from two previous studies, the gain (= relative amplitude increase for relative luminance increase) is close to 0.4 over a range of 56-700 cd/m(2). The stimulus luminance range suggested in the mfERG guidelines seems well chosen.

Effects of Tobacco Smoking on the Kinetics of the Pupillary Light Reflex: A Comparison between Smokers and Non-Smokers

Background: The time course of the pupillary light reflex (PLR) is determined by the successive activation of parasympathetic and sympathetic innervations of the iris, latency and amplitude reflecting parasympathetic activity and recovery time showing mainly sympathetic activity. Objective: To determine the effects of tobacco cigarette smoking on the PLR in smokers after an abstinence period of at least 12 h. Methods: Ten smokers (mean 15.7 cigarettes/day) and 10 non-smokers participated in a randomised, non-intervention controlled, cross-over study that included a parallel control group. Smokers underwent two sessions with a time interval between 3 and 8 days; two recordings were taken at each session, separated by 20 min: session 1, without smoking, and session 2, smoking 3 cigarettes within a 30-min period. Non-smokers underwent one session; two recordings were taken separated by 20 min. At each recording, in both groups, PLR was elicited with four light flashes of increasing luminance. Results: The relationship between PLR parameters and light intensity was linear in each subject. The slope of the regression line for relative amplitude increase versus intensity was significantly flatter in abstinent smokers than in non-smokers (p = 0.033); the slope returned significantly after smoking (p = 0.043). No other significant effects were obtained. Conclusions: Kinetic parameters of PLR provide a sensitive pharmacological test to detect cholinergic neurotransmission manipulation effects, as they seem to detect changes in moderate smokers after 12 h of abstinence, and their reversal on return to smoking. These results suggest an enhancement in the suppression of the parasympathetic oculomotor reflex arc rather than a facilitation of the sympathetic drive to the iris.

Actigraphy in Patients with Seasonal Affective Disorder and Healthy Control Subjects Treated with Light Therapy

Abnormalities of the circadian rest-activity cycle are hypothesized to accompany the clinical picture of seasonal affective disorder (SAD). The purpose of this study was to investigate if bright light therapy (BLT) is able to reverse these disturbances. Seventeen SAD outpatients and 17 sex- and age-matched healthy control subjects were treated with BLT administered in the morning for 4 weeks. Activity levels were measured with wrist actigraphy. SAD patients had 33% lower total (p = .031) and 43% lower daylight activity (p = .006) in week 1 compared with control subjects. The relative amplitude of the sleep-wake cycle was attenuated by 6% in patients (p = .025); they were phase delayed by 55 minutes (p = .023) and had significantly lower sleep efficiency (p = .030). Total (p = .002) and daylight activity (p = .001) increased after 4 weeks of treatment in SAD patients. Moreover, BLT led to increase of relative amplitude (p = .005), advance of delayed rhythms (p = .036), and improved sleep efficiency (p = .011) in patients. Intradaily stability, measuring the strength of coupling of the rhythm to external zeitgebers, increased by 9% both in patients and healthy control subjects (p = .032). Treatment with BLT normalizes disturbed activity patterns and restores circadian rhythms in SAD patients. BLT might also stabilize the circadian rhythm in nondepressed individuals during the fall-winter season.

Noise-enhanced energy transduction of molecular machinery

We have numerically investigated the enhance effect of noise on the energy transduction of molecular machinery. The energy transduction is enhanced with the increase of relative amplitude of the limit-cycle oscillation in polymer chain. And noise can enlarge the relative amplitude through a mechanism of stochastic resonance (SR). In the simulation, two different types of SR, internal signal SR (ISSR) and explicit ISSR (EISSR) are studied, respectively. And the similarity as well as difference between them was presented. The potential application of the enhance effect of energy transduction is then discussed.

Raman spectroscopy study of the structure of lithium and sodium ultraphosphate glasses

Anhydrous binary phosphate glasses containing from 0 to 50 mol% Li 2O or Na 2O have been prepared and examined by Raman scattering spectroscopy. The unpolarized Raman spectrum of vitreous P 2O 5 has intense bands near 640 cm −1, attributed to the symmetric stretching mode of POP bridging oxygens, (POP) sym, between Q 3 phosphate tetrahedra, and at 1390 cm −1 due to the symmetric stretch of the PO terminal oxygens, (PO) sym. With the addition of alkali oxide to P 2O 5, a new feature appears in the Raman spectra near 1160 cm −1 indicating the formation of Q 2 phosphate tetrahedra with two bridging and two non-bridging oxygens. The increase in relative amplitude of this new (PO 2) sym band with increasing modifier content is consistent with a simple depolymerization of the phosphate network. From 20 to 50 mol% alkali oxide, the position of the (PO) sym Raman band decreases by ∼ 130 cm −1 whereas the frequency of the (POP) sym band increases by ∼ 60 cm −1. These frequency shifts are the result of π-bond delocalization on Q 3 species that effectively lengthens the PO terminal oxygen bond and strengthens the POP linkages with increasing alkali oxide content. The compositional dependence of the π-bond delocalization on Q 3 tetrahedra is described by considering the interconnections between neighboring Q 3 and Q 2 tetrahedra. The onset of π-bond delocalization on Q 3 species corresponds with the anomalous T g minimum at 20 mol% alkali oxide in alkali ultraphosphate glasses. The increase in T g between 20 and 50 mol% alkali oxide is attributed to the increased ionic interconnection of what becomes a chain-like phosphate network at higher alkali contents. Finally, the Raman spectra of several alkali ultraphosphate glasses show high frequency shoulders on the Raman bands attributed to the (PO 2) sym and (PO 2) asym vibrational modes. These shoulders represent the presence of strained structural units, possibly three- or four-membered rings.

Detachment of low-force bridges contributes to the rapid tension transients of skinned rabbit skeletal muscle fibres.

1. To probe the cross-bridge cycle and to learn more about the cardioplegic agent BDM (2,3-butanedione monoxime), its effects on the force-velocity properties and tension transients of skinned rabbit muscle fibres were studied at 1-2 degrees C and pH 7.0. 2. Three millimolar BDM decreased isometric force by 50%, velocity by 29%, maximum power by 73%, and stiffness by 25%, so that the relative stiffness (stiffness/force ratio) increased by 50% compared with reference conditions in the absence of BDM. 3. Tension transients obtained under the reference condition (0 BDM) could be represented by three components whose instantaneous stiffness accounted for the initial (Phase 1) force deviation and whose exponential recoveries caused the rapid, partial (Phase 2) force recovery following the step. The fastest component had non-linear extension-force properties that accounted for about half the isometric stiffness and it recovered fully. The two slower components had linear extension-force properties that together accounted for the other half of the sarcomere stiffness. These components recovered only partially following the step, producing the intermediate (T2) level which the force approached during Phase 2. 4. Matching the force transients obtained under test conditions (3 mM BDM) required three alterations: (1) reducing the amplitude of the two slower components by 50%, in proportion to isometric force, (2) adding a non-relaxing component and (3) decreasing the amplitude of the rapidly recovering component by 12.5% so that its relative amplitude (amplitude/isometric force) was increased by 75%. The non-recovering component and the increase in relative amplitude of the rapid component were responsible for the increase in relative stiffness of the fibres produced by BDM. The rapidly recovering component had the same time constant and step-size-dependent recovery rates as the fastest of the three mono-exponential components isolated from the tension transient response under the reference condition. BDM therefore appeared to augment the fastest component of the tension transient under the reference condition. 5. The results suggest that BDM detains cross-bridges in low-force, attached states. Since these bridges are attached, they contribute to sarcomere stiffness. Since they are detained, relaxation or reversal of their immediate responses is probably due to bridge detachment rather than to their undergoing the power stroke. The observation that a portion of the test response matched the fastest component of the reference response when the amplitude of the fastest component was increased suggests that a part of the normal rapid, transient tension recovery following a release step is due to detachment of low-force bridges moved to negative-force positions by the step.

Size dependence of Kondo scattering in point contacts.

By utilizing a mechanically controllable break junction, point contact spectra $\frac{\mathrm{dV}}{\mathrm{dI}}$ were determined for various noble metals (Cu; Au) doped with magnetic impurities (Mn). The contact diameter $d$ could be varied continuously between ca. 2 and 50 nm. The zero bias maximum in $\frac{\mathrm{dV}}{\mathrm{dI}}$ due to the Kondo scattering exhibits a large broadening and increase of relative amplitude as $d$ is decreased. By using the theoretical expression for the logarithmic slope of $\frac{\mathrm{dV}}{\mathrm{dI}}$ vs $V$ we find a significant enhancement of exchange coupling parameter $J$, which leads to an enormous increase in the apparent Kondo temperature ${T}_{K}$ for small contact diameters.

Age-dependent changes of the compound action potential in the guinea pig.

As a measure of age-related changes in the most peripheral neural part of the auditory pathway, the compound action potential of the guinea pig was analyzed. In addition to a marked threshold elevation, there was a significantly lower potential amplitude in old animals. By contrast, the latency of the compound action potential was unchanged. In view of the fact that the relative amplitude increase in the intensity range tested was the same in old as in young animals, the implication is that the auditory-nerve neurons that are still excited do not exhibit functional deterioration with aging.