Microrheology probes length scale dependent rheology

We exploit the power of microrheology to measure the viscoelasticity of entangled F-actin solutions at different length scales from 1 to 100 mu m over a wide frequency range. We compare the behavior of single probe-particle motion to that of the correlated motion of two particles. By varying the average length of the filaments, we identify fluctuations that dissipate diffusively over the filament length. These provide an important relaxation mechanism of the elasticity between 0.1 and 30 rad/sec

Where is my time? Identifying productive time of lifelong learners for effective feedback services

Lifelong learners are confronted with a broad range of activities they have to manage every day. In most cases they have to combine learning, working, family life and leisure activities throughout the day. Hence, learning activities from lifelong learners are disrupted. The difficulty to find a suitable time slot to learn during the day has been identified as the most frequent cause. In this scenario mobile technologies play an important role since they can keep track of the most suitable moments to accomplish specific learning activities in context. Sampling of learning preferences on mobile devices are key benchmarks for lifelong learners to become aware on which learning task suits in which context, set realistic goals and set aside time to learn on a regular basis. The contribution of this manuscript is twofold: first, a classification framework for modelling lifelong learners’ preferences is presented based on a literature review; second, a mobile application for experience sampling is piloted aiming to identify which are the preferences from lifelong learners regarding when, how and where learning activities can be integrated. Both framework and pilot provide an important scaffold for lifelong learners to identify productive times during the day with mobile technologies.NELL

New Pseudo-Phase Structure for α\alpha-Pu

In this paper we propose a new pseudo-phase crystal structure, based on an orthorhombic distortion of the diamond structure, for the ground-state $\alpha$-phase of plutonium. Electronic-structure calculations in the generalized-gradient approximation give approximately the same total energy for the two structures. Interestingly, our new pseudo-phase structure is the same as the Pu $\gamma$-phase structure except with very different b/a and c/a ratios. We show how the contraction relative to the $\gamma$ phase, principally in the $z$ direction, leads to an $\alpha$-like structure in the [0,1,1] plane. This is an important link between two complex structures of plutonium and opens new possibilities for exploring the very rich phase diagram of Pu through theoretical calculations

Strong Attraction between Charged Spheres due to Metastable Ionized States

We report a mechanism which can lead to long range attractions between like-charged spherical macroions, stemming from the existence of metastable ionized states. We show that the ground state of a single highly charged colloid plus a few excess counterions is overcharged. For the case of two highly charged macroions in their neutralizing divalent counterion solution we demonstrate that, in the regime of strong Coulomb coupling, the counterion clouds are very likely to be unevenly distributed, leading to one overcharged and one undercharged macroion. This long-living metastable configuration in turn leads to a long range Coulomb attraction.Comment: REVTEX-published versio

Depletion forces near curved surfaces

Based on density functional theory the influence of curvature on the depletion potential of a single big hard sphere immersed in a fluid of small hard spheres with packing fraction \eta_s either inside or outside of a hard spherical cavity of radius R_c is calculated. The relevant features of this potential are analyzed as function of \eta_s and R_c. There is a very slow convergence towards the flat wall limit R_c \to \infty. Our results allow us to discuss the strength of depletion forces acting near membranes both in normal and lateral directions and to make contact with recent experimental results

Like-charge attraction through hydrodynamic interaction

We demonstrate that the attractive interaction measured between like-charged colloidal spheres near a wall can be accounted for by a nonequilibrium hydrodynamic effect. We present both analytical results and Brownian dynamics simulations which quantitatively capture the one-wall experiments of Larsen and Grier (Nature 385, p. 230, 1997).Comment: 10 pages, 4 figure

Unravelling the health status of brachycephalic dogs in the UK using multivariable analysis

Brachycephalic dog breeds are regularly asserted as being less healthy than non-brachycephalic breeds. Using primary-care veterinary clinical data, this study aimed to identify predispositions and protections in brachycephalic dogs and explore differing inferences between univariable and multivariable results. All disorders during 2016 were extracted from a random sample of 22,333 dogs within the VetCompass Programme from a sampling frame of 955,554 dogs under UK veterinary care in 2016. Univariable and multivariable binary logistic regression modelling explored brachycephaly as a risk factor for each of a series of common disorders. Brachycephalic dogs were younger, lighter and less likely to be neutered than mesocephalic, dolichocephalic and crossbred dogs. Brachycephalic differed to non-brachycephalic types in their odds for 10/30 (33.33%) common disorders. Of these, brachycephalic types were predisposed for eight disorders and were protected for two disorders. Univariable and multivariable analyses generated differing inference for 11/30 (30.67%) disorders. This study provides strong evidence that brachycephalic breeds are generally less healthy than their non-brachycephalic counterparts. Results from studies that report only univariable methods should be treated with extreme caution due to potential confounding effects that have not been accounted for during univariable study design or analysis

Understanding depletion forces beyond entropy

The effective interaction energy of a colloidal sphere in a suspension containing small amounts of non-ionic polymers and a flat glass surface has been measured and calculated using total internal reflection microscopy (TIRM) and a novel approach within density functional theory (DFT), respectively. Quantitative agreement between experiment and theory demonstrates that the resulting repulsive part of the depletion forces cannot be interpreted entirely in terms of entropic arguments but that particularly at small distances ($\lesssim$ 100 nm) attractive dispersion forces have to be taken into account

773-4 Long Term Efficacy and Safety of Endovascular Low Dose Irradiation In a Swine Model of Restenosis After Angloplasty

Restenosis after balloon angioplasty is characterized by neointima formation. We have previously shown that ionizing radiation reduce neointima formation two weeks after angioplasty in a swine model of restenosis. To determine the durability of this effect and the long term safety after endovascular irradiation twenty one miniswine coronary arteries underwent overstretch balloon injury with a 3.5mm angioplasty balloon in the LAD, LCX and RCA. High energy 1921ridium source was introduced immediately by random assignment to deliver 700 or 1400 cGy in 14 injured coronary arteries (LAD and CX). Six months later an angiogram was performed, the animals were killed and the coronary arteries were perfusion fixed. Serial sections were stained with H&E, WG, MT then evaluated by histopathologic and morphometric techniques. Intimal area (IA) and area of intimal thickness corrected for the extent of injury (INFL) was measured in the irradiated and control arteries and compared with pigs that underwent the same treatment but were followed for 2 weeks only.ResultsAll treated arteries were patent with normal angiographic appearance. Lumen diameters at baseline and follow-up were similar. There was no difference in fibrosis at the adventitia, media, perivascular space or adjacent segments of myocardium of the irradiated arteries compared with control.Control700 cGy1400 cGyIN/FL 2Weeks0.59±0.230.42±0.15**0.17±0.16****IN/FL 6 Months0.50±0.20.35±0.18*0.31±0.16**IA 6 Months (mm)1.25±0.250.85±0.47***0.62±0.45**P values: control versus treatment group:*P=0.009**P<0.001***P=0.05.****P<0.0001ConclusionsEndovascular low dose irradiation in this model is safe andthe inhibitory effect of localized radiation on neointimal thickening (restenos is like) response to angioplasty is maintained at six months