Exercise intensity and postprandial health outcomes in adolescents

© 2014, Springer-Verlag Berlin Heidelberg. Method: Twenty adolescents (10 male, 14.3 ± 0.3 years) completed three 1-day trials: (1) rest (CON); (2) 8 × 1 min cycling at 90 % peak power with 75 s recovery (HIIE); (3) cycling at 90 % of the gas exchange threshold (MIE), 1 h before consuming a high-fat milkshake (1.50 g fat and 80 kJ kg−1). Postprandial TAG, SBP and fat oxidation were assessed over 4 h Results : Compared to CON, the incremental area under the curve for TAG (IAUC-TAG) was not significantly lowered in HIIE [P = 0.22, effect size (ES) = 0.24] or MIE (P = 0.65, ES = 0.04) for boys. For girls, HIIE and MIE lowered IAUC-TAG by 34 % (P = 0.02, ES = 0.58) and 38 % (P = 0.09, ES = 0.73), respectively, with no difference between HIIE and MIE (P = 0.74, ES = 0.14). Changes in TAG were not related to energy expenditure during exercise or postprandial fat oxidation. Postprandial SBP (total-AUC pooled for both sexes) was lower in HIIE compared to CON (P = 0.01, ES = 0.68) and MIE (P = 0.02, ES = 0.60), with no difference between MIE and CON (P = 0.45, ES = 0.14). Purpose: The effect of exercise intensity and sex on postprandial risk factors for cardiovascular disease in adolescents is unknown. We examined the effect of a single bout of work-matched high-intensity interval exercise (HIIE) and moderate-intensity exercise (MIE) on postprandial triacylglycerol (TAG) and systolic blood pressure (SBP) in adolescents. Conclusion: A single bout of HIIE and MIE, performed 1 h before an HFM, can meaningfully attenuate IAUC-TAG in girls but not boys. Additionally, HIIE, but not MIE, may lower postprandial SBP in normotensive adolescents

Flexible terahertz wire grid polarizer with high extinction ratio and low loss

An aluminum-based THz wire grid polarizer is theoretically investigated and experimentally demonstrated on a sub-wavelength thin flexible and conformal foil of the cyclo-olefin Zeonor© polymer. THz time-domain spectroscopy characterization, performed on both flat and curved configurations, reveals a high extinction ratio between 40 and 45 dB in the 0.3-1 THz range and in excess of 30 dB up to 2.5 THz. The insertion losses are lower than 1 dB and are almost exclusively due to moderate Fabry-Perót reflections, which vanish at targeted frequencies. The polarizer can be easily fabricated with low-cost techniques such as roll-to-roll and/or large area electronics processes and promises to pen the way for a new class of flexible and conformal THz devices

Scientific Advice to Public Policy-Making

A feature of policy-making today is its dependence on scientific advice to deliver public policies that are robust, credible, and effective. This paper discusses how policy-making profits from scientific advice in areas where science and technology are significant. Particular attention is given to issues holding a high level of uncertainty, either because of inherent variability, because science is incomplete or controversial, or because data are inadequate to support a definitive answer. First, we analyse the social context that characterises the relationship between science and policy-making, with a focus on the decrease of public confidence in politicians and scientists. Second, we compare three different sets of guidelines on the collection and use of expertise in policy-making (issued by the UK, Canada and the European Commission, respectively) and identify two different approaches to scientific advice in policy-making. Third, based on a set of cross-national and multi-disciplinary case studies, we look at how the relationship between science and policy-making works in practice and propose a set of recommendations towards the establishment of a more robust and effective policy-making process

Electromagnetic wave scattering on imperfect cloaking devices

Cloaking devices based on the coordinate transform approach enable, in principle, a perfect concealment of a region in space provided that the material composing the cloaking shell meets certain criteria. To achieve ideal cloaking it is necessary that the shell material parameters have singular values on the surface bounding the cloaked region which is unphysical. In this paper we assume finite values of cloak parameters and apply the scattering theory formalism to give an estimate of the overall performance of an 'imperfect' cloak. We perform full-wave numerical calculations and use our theoretical results to discuss them

Spectral and Directional Reshaping of Fluorescence in Large Area Self-Assembled Plasmonic–Photonic Crystals

Spectral and directional reshaping of fluorescence from dye molecules embedded in self-assembled hybrid plasmonic–photonic crystals has been examined. The hybrid crystals comprise two-dimensional hexagonal arrays of dye-doped dielectric nanospheres, capped with silver semishells. Comparing the reshaped fluorescence spectra with measured transmission/reflection spectra and numerical calculations reveals that the spectral and directional reshaping of fluorescence is the result of its coupling to photonic crystal Bloch modes and to void plasmons localized inside the silver caps

Oblique incidence ellipsometric characterization and the substrate dependence of visible frequency fishnet metamaterials

We use spectroscopic ellipsometry to investigate the angular-dependent optical modes of fishnet metamaterials fabricated by nanoimprint lithography. Spectroscopic ellipsometry is demonstrated as a fast and efficient method for metamaterial characterization and the measured polarization ratios significantly simplify the calibration procedures compared to reflectance and transmittance measurements. We show that the modes can be well identified by a combination of comparing different substrates and considering the angular dependence of the Wood's anomalies. The lack of angular dispersion of the anti-symmetric gap-modes does not agree with the model and requires further theoretical investigation

Diabetes-induced cardiomyocyte passive stiffening is caused by impaired insulin-dependent titin modification and can be modulated by neuregulin-1

Rationale: Increased titin-dependent cardiomyocyte tension is a hallmark of heart failure with preserved ejection fraction associated with type-2 diabetes mellitus. However, the insulin-related signaling pathways that modify titin-based cardiomyocyte tension, thereby contributing to modulation of diastolic function, are largely unknown. Objective: We aimed to determine how impaired insulin signaling affects titin expression and phosphorylation and thus increases passive cardiomyocyte tension, and whether metformin or neuregulin-1 (NRG-1) can correct disturbed titin modifications and increased titin-based stiffness. Methods and Results: We used cardiac biopsies from human diabetic (n=23) and nondiabetic patients (n=19), cultured rat cardiomyocytes, left ventricular tissue from apolipoprotein E–deficient mice with streptozotocin-induced diabetes mellitus (n=12–22), and ZSF1 (obese diabetic Zucker fatty/spontaneously hypertensive heart failure F1 hybrid) rats (n=5–6) and analyzed insulin-dependent signaling pathways that modulate titin phosphorylation. Titin-based passive tension was measured using permeabilized cardiomyocytes. In human diabetic hearts, we detected titin hypophosphorylation at S4099 and hyperphosphorylation at S11878, suggesting altered activity of protein kinases; cardiomyocyte passive tension was significantly increased. When applied to cultured cardiomyocytes, insulin and metformin increased titin phosphorylation at S4010, S4099, and S11878 via enhanced ERK1/2 (extracellular signal regulated kinase 1/2) and PKCα (protein kinase Cα) activity; NRG-1 application enhanced ERK1/2 activity but reduced PKCα activity. In apolipoprotein E–deficient mice, chronic treatment of streptozotocin-induced diabetes mellitus with NRG-1 corrected titin phosphorylation via increased PKG (protein kinase G) and ERK1/2 activity and reduced PKCα activity, which reversed the diabetes mellitus–associated changes in titin-based passive tension. Acute application of NRG-1 to obese ZSF1 rats with type-2 diabetes mellitus reduced end-diastolic pressure. Conclusions: Mechanistically, we found that impaired cGMP–PKG signaling and elevated PKCα activity are key modulators of titin-based cardiomyocyte stiffening in diabetic hearts. We conclude that by restoring normal kinase activities of PKG, ERK1/2, and PKCα, and by reducing cardiomyocyte passive tension, chronic NRG-1 application is a promising approach to modulate titin properties in heart failure with preserved ejection fraction associated with type-2 diabetes mellitus. </jats:sec