The myotendinous junction (MTJ) is the interface between muscle and tendon, and it is the main area of force transmission of the locomotor apparatus. Dystrophic processes promote pathological injury which affects the skeletal muscle and can influence the morphology of the MTJ. This study aimed to investigate the adaptations in MTJ morphology of mdx mice in the tibialis anterior muscle. Male mice (n = 24) were divided into Control—C57bl/10 and mdx—C57bl/10mdx (Duchenne muscular dystrophy experimental model). In the mdx group, centralized nuclei with a large area and greater deposition of type III collagen (fibrosis) were observed. Also, shorter sarcomeres and sarcoplasmatic projections of MTJ were observed. We concluded that the adaptations in mdx mice demonstrated extensive impairment in the MTJ region with reduced ultrastructures.

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Richtmyer–Meshkov instability causes spatially periodic perturbations initially imposed on a shock-accelerated, thin gas layer to develop into one of three distinct flow patterns. Planar laser-induced fluorescence imaging of the evolving layer, produced by a perturbed SF6 planar jet in air, shows an apparent flow bifurcation that is observed as mushroom-shaped or sinuous-shaped interfacial patterns. Analysis of this nonlinear instability growth, accomplished by modelling the flow field as a row of line vortices, predicts that the layer thickness grows logarithmically at later times and compares well with our measurements. Because the row of vortices is unstable, the model also provides an explanation for the appearance of the three observed interfacial patterns.

Recent studies have revealed that, in contrast to non-associating liquids such as oils or organic solvents, salt-free water retains a viscosity close to its bulk value even when confined to films thinner than some 3 nm, indeed down to only one or two monolayers thick [1,2]. For the case of high concentration aqueous salt solution compressed down to subnanometer films between charged surfaces, the trapped hydrated ions serve to act as molecular ball-bearings, sustaining a large load while remaining very fluid under shear [3]. This behaviour is attributed to the tenacity of the hydration sheaths together with their rapid relaxation time. Finally, a very recent study [4] has shown that when charged polymer brushes in aqueous media are compressed and slid past each other, they provide a lubrication that is considerably superior to that afforded by neutral brushes: This is attributed on the one hand to the resistance to mutual interpenetration of the chains due to entropic barriers in the good-solvent conditions, and, on the other hand, to the hydration-sheaths on the charged polymer segments which can act – as noted above – as molecular ball-bearings.

A model is presented for the shear (or frictional) forces Fs between two surfaces a distance D apart as they slide past each other while bearing mutually compressed polymer brushes, on the assumption that sliding takes place at the brush-brush interface. The predictions of the model for the rapid increase in Fs at increasing compressions are in reasonable agreement with experiments on polystyrene brushes immersed in toluene over two decades in Fs. At higher compressions (smaller D) the experimental shear forces increase only slowly, and diverge from the calculated ones which continue to increase rapidly; at the same time the form of the shear force response at these higher compressions reverts from a viscous-like one to a stick-slip behaviour. These observations strongly indicate that at sufficiently high compressions the plane of slip crosses over from the brush-brush interface to the polymer-solid surface.

A founder haplotype on chromosome 2p for autosomal dominant Parkinson's disease (PD) has been postulated for two families of Northern European descent, and a new mutation in the α-synuclein gene (Ala30Pro) has been found in a German PD family. We evaluated 85 German PD patients and 85 ethnically matched controls for shared markers on chromosome 2p and for the new α-synuclein mutation. We found no evidence for linkage disequilibrium, suggesting that the putative founder mutation on chromosome 2p is not a common cause of PD in the local population. Furthermore, no patient carried the Ala30Pro change, supporting earlier findings that mutations in the α-synuclein gene are extremely rare.

Thermal conductivity measurements were performed on several amorphous rare earth transition metal thin films of varying microstructure. The thermal conductivity perpendicular to the plane of the film, measured by the thermal comparator method, was compared with the thermal conductivity value measured parallel to the plane of the film. The latter value was obtained by converting electrical conductivity values to thermal conductivity via the Wiedemann–Franz relationship. As expected, the columnar microstructure induced during the sputter deposition of the thin films causes an anisotropy in the thermal conductivity values, with the in-plane values consistently lower than the out-of-plane values. The effect is most pronounced for the more columnar films deposited at higher pressure, for which the in-plane thermal conductivity, 0.3 W/mK, is an order of magnitude lower than the out-of-plane thermal conductivity, 4.3 W/mK. The thermal conductivity out of the plane of the film decreased with increasing deposition pressure, due to the decreasing film density.

Anomalously low laser damage resistance thresholds have been observed in many thin film systems. Thermal conductivity values well below bulk have been suggested as a possible cause. A series of reactively sputtered AIN films were deposited on fused quartz and sapphire substrates. Their thermal conductivities were measured using the thermal comparator technique. Important factors contributing to the apparently large thermal resistance in the AIN films include film surfaces, small grain size, and high oxygen concentration. Preferred orientation and columnar morphology also affect film conductivity. Film microstructures were observed by transmission electron microscopy, and correlated with measured values of thermal conductivity.

We have measured the composition profile between two polymer phases above and below their critical temperature for phase separation Tc, using the 2H(3He,4He)1H nuclear reaction in a direct profiling technique. Above Tc, we verify the “thtrmodynamic slowing down” effects on interdiffusion close to the critical point. Pelow Tc, we find that the width of the interface grows with time to a finite limiting value. The variation of this limiting value, as Tc, is approached from below is in good agreement with the predictions of mean-field theories. The time dependence of the initial interfacial broadening below Tc has been found to be significantly slower than t1/2.