Effects of low-frequency whole-body vibration on motor-evoked potentials in healthy men.

addresses: Sport and Exercise Science Research Centre, Faculty of Engineering, Science and The Built Environment, London South Bank University, 103 Borough Road, London SE1 0AA, UK. [email protected] is the author's post-print version of an article published in Experimental Physiology, 2009, Vol. 94, Issue 1, pp. 103 - 116 Copyright © 2009 Wiley-Blackwell /The Physiological Society. The definitive version is available at www3.interscience.wiley.comThe aim of this study was to determine whether low-frequency whole-body vibration (WBV) modulates the excitability of the corticospinal and intracortical pathways related to tibialis anterior (TA) muscle activity, thus contributing to the observed changes in neuromuscular function during and after WBV exercise. Motor-evoked potentials (MEPs) elicited in response to transcranial magnetic stimulation (TMS) of the leg area of the motor cortex were recorded in TA and soleus (SOL) muscles of seven healthy male subjects whilst performing 330 s continuous static squat exercise. Each subject completed two conditions: control (no WBV) and WBV (30 Hz, 1.5 mm vibration applied from 111 to 220 s). Five single suprathreshold and five paired TMS were delivered during each squat period lasting 110 s (pre-, during and post-WBV). Two interstimulus intervals (ISIs) between the conditioning and the testing stimuli were employed in order to study the effects of WBV on short-interval intracortical inhibition (SICI, ISI = 3 ms) and intracortical facilitation (ICF, ISI = 13 ms). During vibration relative to squat exercise alone, single-pulse TMS provoked significantly higher TA MEP amplitude (56 +/- 14%, P = 0.003) and total area (71 +/- 19%, P = 0.04), and paired TMS with ISI = 13 ms provoked smaller MEP amplitude (-21 +/- 4%, P = 0.01) but not in SOL. Paired-pulse TMS with ISI = 3 ms elicited significantly lower MEP amplitude (TA, -19 +/- 4%, P = 0.009; and SOL, -13 +/- 4%, P = 0.03) and total area (SOL, -17 +/- 6%, P = 0.02) during vibration relative to squat exercise alone in both muscles. Tibialis anterior MEP facilitation in response to single-pulse TMS suggests that WBV increased corticospinal pathway excitability. Increased TA and SOL SICI and decreased TA ICF in response to paired-pulse TMS during WBV indicate vibration-induced alteration of the intracortical processes as well

Genomic structural variations lead to dysregulation of important coding and non-coding RNA species in dilated cardiomyopathy

The transcriptome needs to be tightly regulated by mechanisms that include transcription factors, enhancers, and repressors as well as non-coding RNAs. Besides this dynamic regulation, a large part of phenotypic variability of eukaryotes is expressed through changes in gene transcription caused by genetic variation. In this study, we evaluate genome-wide structural genomic variants (SVs) and their association with gene expression in the human heart. We detected 3,898 individual SVs affecting all classes of gene transcripts (e.g., mRNA, miRNA, lncRNA) and regulatory genomic regions (e.g., enhancer or TFBS). In a cohort of patients (n = 50) with dilated cardiomyopathy (DCM), 80,635 non-protein-coding elements of the genome are deleted or duplicated by SVs, containing 3,758 long non-coding RNAs and 1,756 protein-coding transcripts. 65.3% of the SV-eQTLs do not harbor a significant SNV-eQTL, and for the regions with both classes of association, we find similar effect sizes. In case of deleted protein-coding exons, we find downregulation of the associated transcripts, duplication events, however, do not show significant changes over all events. In summary, we are first to describe the genomic variability associated with SVs in heart failure due to DCM and dissect their impact on the transcriptome. Overall, SVs explain up to 7.5% of the variation of cardiac gene expression, underlining the importance to study human myocardial gene expression in the context of the individual genome. This has immediate implications for studies on basic mechanisms of cardiac maladaptation, biomarkers, and (gene) therapeutic studies alike

Climate Impact Storylines for Assessing Socio-Economic Responses to Remote Events

Complex interactions involving climatic features, socio-economic vulnerability or responses, and long impact transmissions are associated with substantial uncertainty. Physical climate storylines are proposed as approach to explore complex impact transmission pathways and possible alternative unfolding of event cascades under future climate conditions. These storylines are particularly useful for climate risk assessment for complex domains, including event cascades crossing multiple disciplinary or geographical borders. For an effective role in climate risks assessments, practical guidelines are needed to consistently develop and interpret the storyline event analyses.This paper elaborates on the suitability of physical climate storyline approaches involving climate event induced shocks propagating into societal impacts. It proposes a set of common elements to construct the event storylines. In addition, criteria for their application for climate risk assessment are given, referring to the need for storylines to be physically plausible, relevant for the specific context, and risk-informative.Six examples of varying scope and complexity are presented, all involving the potential climate change impact on European socio-economic sectors induced by remote climate change features occurring far outside the geographical domain of the European mainland. The storyline examples illustrate the application of the proposed storyline components and evaluates the suitability criteria defined in this paper. It thereby contributes to the standardization of the design and application of event-based climate storyline approaches

Calibration concept for a GPR monitoring system and methods for arrival time picking

Calibration of ground penetrating radar (GPR) measurement systems isindispensable to enable quantitative and high resolution data analysisespecially for high resolution soil research as well as inversion approachesfor a wide range of applications. This work presents a concept for an in situcalibration of GPR monitoring systems which enables to perform acalibration that is not solely based on signals traveling in air. A classicalcalibration via signals traveling in air is not feasible in our setup, since thesystem is permanently positioned around a test specimen, e.g. a soil column.The calibration concept is based on the ability to use each antenna as bothtransmitter or receiver and, thereby, perform reciprocal measurements.Initial test measurements indicate the reliability of reciprocal measurementsfor an in situ calibration of our monitoring system with relative accuracies ofdown to 2 ps

Numerical correction of phase errors due to leakage currents in wideband EIT measurements.

Advanced model-based data correction methods are needed in order to determine the small phase response of low-polarizable soils and rocks in the higher frequency range up to 10 kHz. Methods have been developed to correct several system-dependent errors, such as amplification errors, signal drift, current measurement errors, potential measurement errors due to high electrode impedances, propagation delay of the signal due to the long cables, and phase errors introduced by inductive coupling between the electrode cables. However, measurements at test sites with high resistivity have shown a new dominating phase error, which was found to be related to capacitive leakage currents between system ground and the soil. In order to correct this error, we enhanced the FEM modelling used for the reconstruction of the electrical conductivity distribution. Using this new formulation of the FEM forward model, this source of error was reduced by a factor of five or more. This enables an electrical conductivity reconstruction for frequencies up to 10 kHz. In future work, it will be investigated whether the capacitive leakage currents can be reduced by optimization of the cable layout. In any case, it is helpful to use the leakage current as a proxy for data error during data filtering, and it can also be used to decide if the enhanced FEM model presented here should be used

Correction of phase errors due to leakage currents in wideband EIT field measurements on soil and sediments

Electrical impedance tomography (EIT) is a promising method to characterize important hydrological properties of soil, sediments, and rocks. The characterization is based on the analysis of the phase response of the complex electrical conductivity in a broad frequency range (i.e. mHz to kHz). However, it is challenging to measure the small phase response of low-polarizable soils and rocks in the higher frequency range up to 10 kHz. In order to achieve the required phase accuracy in the kHz frequency range, an optimized measurement system and advanced model-based processing methods have been developed. Recently, EIT measurements at sites with low electrical conductivity have shown a new dominating phase error related to capacitive leakage currents between cable shields and soil. In order to correct this phase error, we developed an advanced finite element model that considers both leakage currents and capacitive coupling between the soil and the cable shields in the reconstruction of the complex electrical conductivity distribution. This advanced model also takes into account potential measurement errors due to high electrode impedances. The use of this advanced model reduced the new dominating error for media with low electrical conductivity. It was also found that the amount of leakage current is an additional indicator for data quality that can be used for data filtering. After application of a novel data filter based on the leakage current and the use of the advanced modelling approach, the phase error of the measured transfer impedances above 100 Hz was significantly reduced by a factor of 6 or more at 10 kHz. In addition, physically implausible positive phase values were effectively eliminated. The new correction method now enables the reconstruction of the complex electrical conductivity for frequencies up to 10 kHz at field sites with a low electrical conductivity