Impact of retrograde shear rate on brachial and superficial femoral artery flow-mediated dilation in older subjects

An inverse, dose-dependent relationship between retrograde shear rate and brachial artery endothelial function exists in young subjects. This relationship has not been investigated in older adults, who have been related to lower endothelial function, higher resting retrograde shear rate and higher risk of cardiovascular disease. Aim To investigate the impact of a step-wise increase in retrograde shear stress on flow-mediated dilation in older males in the upper and lower limbs. Methods Fifteen older (68±9 years) men reported to the laboratory 3 times. We examined brachial artery flow-mediated dilation before and after 30-minutes exposure to cuff inflation around the forearm at 0, 30 and 60 mmHg, to manipulate retrograde shear rate. Subsequently, the 30-minute intervention was repeated in the superficial femoral artery. Order of testing (vessel and intervention) was randomised. Results Increases in cuff pressure resulted in dose-dependent increases in retrograde shear in both the brachial and superficial femoral artery in older subjects. In both the brachial and the superficial femoral artery, no change in endothelial function in response to increased retrograde shear was observed in older males (‘time’ P=0.274, ‘cuff*time P=0.791’, ‘cuff*artery*time P=0.774’). Conclusion In contrast with young subjects, we found that acute elevation in retrograde shear rate does not impair endothelial function in older humans. This may suggest that subjects with a priori endothelial dysfunction are less responsive or requires a larger shear rate stimulus to alter endothelial function

Measurement of the speed-of-light perturbation of free-fall absolute gravimeters

We report on a direct measurement of the relativistic Doppler shift with a commercial free-fall absolute gravimeter of the type FG5X. The observed Doppler shift, which is commonly called speed-of-light perturbation, can be well described by the relativistic Doppler formula, where the constant object velocity is replaced by a time-dependent velocity with constant acceleration. The observed speed-of-light perturbation stands in contrast to other publications, which predict a higher frequency shift. It has been measured with a relative uncertainty of 1.1 × 10 −3

Seismic-frequency attenuation and moduli estimates using a fiber-optic strainmeter

Summary We have developed a fiber-optic strainmeter to estimate velocities and attenuation at seismic frequencies. The two main advantages of the new system compared to strain gage techniques are the higher sensitivity to deformations (moduli) and phase lags (attenuation), and that estimates are representative of bulk values. While stress-strain measurements using strain gages or ultrasonic wave propagation sample only part of the core sample, the fiber-optic strainmeter would analyze the rock sample response to an applied stress as a whole. Still, the system is under development and the first experiment on a Plexiglas sample showed that attenuation estimates are more robust than deformation estimates due to difficulties with light intensity. Initial rock measurements are made on a dolomite sample

Changes in absolute gravity 2000–2015, South Island, New Zealand

<p>We quantify changes in gravity that have occurred over the past 15 years at 14 points between latitudes 42.5°S and 44°S in the South Island of New Zealand. Ten of the points form two transects across the Southern Alps and four lie in the epicentral region of the 2010 Canterbury earthquakes. At each location gravity was measured using an absolute gravimeter (FG5–111) with a nominal accuracy of 1 µGal. Observed changes in gravity varied from −53 to +43 µGal in the presence of surface elevation changes in the range −11 cm to +20 cm. Despite the difficulty in quantifying gravitational contributions from surface and subsurface water, uplift in both the Southern Alps and the Christchurch region is consistent with a Bouguer surface gradient of approximately 1.97 µGal cm^–1, appropriate for the mean density of crustal rocks.</p

Incidence of complications associated with tibial tuberosity advancement in Boxer dogs

Objective: To retrospectively review and describe the incidence of complications associated with tibial tuberosity advancement (TTA) surgical procedures in a group of Boxer dogs (n = 36 stifles) and compare the data with a non-Boxer control population (n = 271 stifles). Methods: Retrospective analysis of medical records to identify all dogs that underwent TTA surgery due to cranial cruciate ligament disease. These records were categorized into two groups: Boxer dogs and non-Boxer dogs (controls – all other breeds). Results: Of the 307 stifles included, 69 complications were reported in 58 joints. The complication rate differed significantly for Boxer dogs (16/36 stifles) and non-Boxer dogs (42/271 stifles), corresponding to an odds ratio of 5.8 (confidence interval: 1.96–17.02; p-value &#60;0.001). Boxer dogs were more likely to undergo revision surgery and to develop multiple complications. The incidence of tibial tuberosity fractures requiring surgical repair (2/36 versus 1/271) and incisional infections requiring antibiotic treatment (three in each group) was significantly higher in the Boxer group. Clinical significance: Boxer dogs had more major and multiple complications after TTA surgery than the control non-Boxer group; these complications included higher rates of revision surgery, tibial tuberosity fractures requiring stabilization, and infection related complications. The pertinence and value of breed-specific recommendations for cranial cruciate ligament disease appears to be a subject worthy of further investigation

Appropriate exercise prescription in primary and secondary prevention of cardiovascular disease:why this skill remains to be improved among clinicians and healthcare professionals. A call for action from the EXPERT Network(&amp; DAG;)

In Europe alone, on a yearly basis, millions of people need an appropriate exercise prescription to prevent the occurrence or progression of cardiovascular disease (CVD). A general exercise recommendation can be provided to these individuals (at least 150 min of moderate-intensity endurance exercise, spread over 3-5 days/week, complemented by dynamic moderate-intensity resistance exercise 2 days/week). However, recent evidence shows that this one size does not fit all and that individual adjustments should be made according to the patient's underlying disease(s), risk profile, and individual needs, to maximize the clinical benefits of exercise. In this paper, we (i) argue that this general exercise prescription simply provided to all patients with CVD, or elevated risk for CVD, is insufficient for optimal CVD prevention, and (ii) show that clinicians and healthcare professionals perform heterogeneously when asked to adjust exercise characteristics (e.g. intensity, volume, and type) according to the patient's condition, thereby leading to suboptimal CVD risk factor control. Since exercise training is a class 1A intervention in the primary and secondary prevention of CVD, the awareness of the need to improve exercise prescription has to be raised among clinicians and healthcare professionals if optimized prevention of CVD is ambitioned

Unconventional conductivity increase in multilayer black phosphorus

Abstract Multilayers of so-called 2D van der Waals materials have gained considerable attention as active components of next-generation electronic and optoelectronic technologies, with semiconducting black phosphorus (BP) regarded as one of the most promising systems. The applicability and performance limits of BP in both stand-alone and heterostructure-based multilayer devices are determined by individual flake charge transport properties, which synergistically depend on the number of layers and the strength of interlayer coupling between those. In this work, we study the DC electrical transport characteristics of high-quality BP field-effect devices within a wide range of flake thicknesses at room temperature. The experimental data show a non-trivial increase in conductivity and hole density with a reduced number of layers while maintaining constant field-effect mobility due to the prevalence of electron–phonon scattering. Based on the solution of the 1D Schrödinger–Poisson equation, we find that the observed phenomena are a direct consequence of non-negligible interlayer coupling, which in turn causes a local redistribution of free charge carriers towards the central layers. Our data show that due to the electrostatic conditions at the flake surfaces, a naturally protected 2D hole gas can be encapsulated in flakes as high as 10 nm, which preserves the bulk-like bandgap and effective carrier masses due to the electrostatic environment