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This article, published in the journal Neuropediatrics, discusses the use of MRI imaging in 10 children with enterovirus-associated acute flaccid myelitis (AFM). AFM is characterized by limb weakness, decreased muscle tone, and cranial nerve involvement, and is predominantly caused by enterovirus infections. The MRI findings in these patients showed longitudinal spinal cord lesions mainly affecting the gray matter, as well as lesions in the brainstem and cerebellum. Supratentorial involvement was uncommon. The study confirms previous findings about the MRI imaging findings in enterovirus-associated AFM. [Extracted from the article]

Presenting simple coarse-grained models of isotropic solids and fluids in d = 1 , 2 and 3 dimensions we investigate the correlations of the instantaneous pressure and its ideal and excess contributions at either imposed pressure (NPT-ensemble, λ = 0 or volume (NVT-ensemble, λ = 1 and for more general values of the dimensionless parameter λ characterizing the constant-volume constraint. The stress fluctuation representation $$\left. {\mathcal{F}_{Row} } \right|_{\lambda = 0} = Kf_0 (x)$$ of the compression modulus K in the NVT-ensemble is derived directly (without a microscopic displacement field) using the well-known thermodynamic transformation rules between conjugated ensembles. The transform is made manifest by computing the Rowlinson functional $$\mathcal{F}_{Row}$$ also in the NPT-ensemble where $$\left. {\mathcal{F}_{Row} } \right|_{\lambda = 0} = Kf_0 (x)$$ with x = Pid/ K being a scaling variable, Pid the ideal pressure and f0( x) = x(2− x) a universal function. By gradually increasing λ by means of an external spring potential, the crossover between both classical ensemble limits is monitored. This demonstrates, e.g., the lever rule $$\left. {\mathcal{F}_{Row} } \right|_\lambda = K\left[ {\lambda + (1 - \lambda )f_0 (x)} \right]$$ . Graphical abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract.: From equilibrium molecular dynamics (MD) simulations of a bead-spring model for short-chain glass-forming polymer melts we calculate several quantities characterizing the single-monomer dynamics near the (extrapolated) critical temperature Tc of mode-coupling theory: the mean-square displacement g0(t), the non-Gaussian parameter α2(t) and the self-part of the van Hove function Gs(r,t) which measures the distribution of monomer displacements r in time t. We also determine these quantities from a continuous-time random walk (CTRW) approach. The CTRW is defined in terms of various probability distributions which we know from previous analysis. Utilizing these distributions the CTRW can be solved numerically and compared to the MD data with no adjustable parameter. The MD results reveal the heterogeneous and non-Gaussian single-particle dynamics of the supercooled melt near Tc. In the time window of the early α relaxation α2(t) is large and Gs(r,t) is broad, reflecting the coexistence of monomer displacements that are much smaller (“slow particles”) and much larger (“fast particles”) than the average at time t, i.e. than r=g0(t)1/2. For large r the tail of Gs(r,t) is compatible with an exponential decay, as found for many glassy systems. The CTRW can reproduce the spatiotemporal dependence of Gs(r,t) at a qualitative to semiquantitative level. However, it is not quantitatively accurate in the studied temperature regime, although the agreement with the MD data improves upon cooling. In the early α regime we also analyze the MD results for Gs(r,t) via the space-time factorization theorem predicted by ideal mode-coupling theory. While we find the factorization to be well satisfied for small r, both above and below Tc, deviations occur for larger r comprising the tail of Gs(r,t). The CTRW analysis suggests that single-particle “hops” are a contributing factor for these deviations.Graphical abstract: [ABSTRACT FROM AUTHOR]