Effects of lipopolysaccharide-induced inflammation on expression of growth-associated genes by corticospinal neurons

Background  

Inflammation around cell bodies of primary sensory neurons and retinal ganglion cells enhances expression of neuronal growth-associated genes and stimulates axonal regeneration. We have asked if inflammation would have similar effects on corticospinal neurons, which normally show little response to spinal cord injury. Lipopolysaccharide (LPS) was applied onto the pial surface of the motor cortex of adult rats with or without concomitant injury of the corticospinal tract at C4. Inflammation around corticospinal tract cell bodies in the motor cortex was assessed by immunohistochemistry for OX42 (a microglia and macrophage marker). Expression of growth-associated genes c-jun, ATF3, SCG10 and GAP-43 was investigated by immunohistochemistry or in situ hybridisation.     

A note on terminology in multigrid methods

We compare terminology used in the literature on multigrid methods for compressible computational fluid dynamics to that used in linear multigrid theory. Several popular iterative and direct smoothers are presented side-by-side using the same terminology. We argue for greater analysis of these methods in order to place them into a more rigorous framework and to identify the most promising candidates for future development. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Reversible Photoswitching of Isolated Ionic Hemiindigos with Visible Light

Indigoid chromophores have emerged as versatile molecular photoswitches, offering efficient reversible photoisomerization upon exposure to visible light. Here we report synthesis of a new class of permanently charged hemiindigos (HIs) and characterization of photochemical properties in gas phase and solution. Gas-phase studies, which involve exposing mobility-selected ions in a tandem ion mobility mass spectrometer to tunable wavelength laser radiation, demonstrate that the isolated HI ions are photochromic and can be reversibly photoswitched between Z and E isomers. The Z and E isomers have distinct photoisomerization response spectra with maxima separated by 40–80 nm, consistent with theoretical predictions for their absorption spectra. Solvation of the HI molecules in acetonitrile displaces the absorption bands to lower energy. Together, gas-phase action spectroscopy and solution NMR and UV/Vis absorption spectroscopy represent a powerful approach for studying the intrinsic photochemical properties of HI molecular switches.     

Methods for optimizing gas transmission networks

We describe two methods for the optimization of gas transmission networks. The first method reduces the number of variables in the optimization problem by eliminating the pipe-flow variables. The second method solves an optimization problem with the full set of variables to achieve better behaviour. These two methods are compared by a series of tests based on the British Gas NTS (National Transmission System). The results of these tests are reported. By formulating the network problem as an optimization problem we have been able to replace heuristics by well proven methods. The reliability of the algorithm using the reduced set of unknowns varied depending on the size of problem and the type of objective function being minimized. The algorithm using the full set of unknowns had no such difficulties, even though it needs to be used with some care. The algorithm is robust in the sense that when the objective function has the necessary continuities, there is a feasible point and the penalty terms ensure positive curvature, then a solution is found reliably. The algorithm based on the reduced set of unknowns is considerably faster than that using the full set, when it succeeds. The factor between the times taken ranges from 1.2 to 5 (average 3) for the smallest network. For the second case comparison is harder since the reduced set algorithm was given a head start in five cases. For the other five the factor is between 2.3 and 8.3. For the largest problem there is just one case in which the comparison is on equal terms, and here the factor is 18. It is clear that the reliability of the full set algorithm is bought at a considerable cost which rises as the problem gets bigger. The main conclusion is that the Sequential Augmented Lagrange Method yields a reliable algorithm for minimizing objective functions of practical interest based on gas networks such as the British Gas National Transmission System. It is not satisfactory to carry over to the case with machines techniques like those of the nodal and loop methods which work well on networks with no machines.     

Analysis methods and size effects in the indentation fracture toughness assessment of very thin oxide coatings on glass

Very thin oxide coatings (<100 nm) which are used as anti-reflection and barrier layers in low emissivity architectural glass have been studied by nanoindentation methods to determine the effect of coating thickness on fracture toughness. Traditional microindentation-derived methods to determine the fracture toughness are unsuitable for assessing very thin coatings (<500 nm) and alternative energy-based models are required depending on what features are visible in indentation load–displacement curves. In cases where radial cracks are formed and grow in a discontinuous manner there are excursions in the load–displacement curve which can be the basis for analysis. In cases where picture frame cracks are observed there are no such features and an alternative approach based on assessment of irreversible work of indentation is required. This paper reviews the methods for obtaining fracture toughness data for very thin coatings and assesses the existence of size effects in the mechanical response of oxide coatings with different thickness on a glass substrate. For oxide coatings in the thickness range 100 to 400 nm no size effects in fracture toughness were observed.     

An in situ neutron diffraction measurement of the pressure–temperature evolution of a MgD2:TiD2 mixture

The hydrogen storage capacity of Mg–Ti–H films is approximately five times that of conventional metal hydride electrodes in NiMH-batteries. Mg and Ti are considered to be immiscible in the bulk and the ambient pressure phase diagram of Mg and Ti indicates that no binary stable bulk compounds are formed. However, in the presence of hydrogen, an Mg–Ti–H phase has been obtained by Kyoi et al. using a high pressure synthesis – where magnesium hydride is compacted with different TM-hydrides in an anvil cell at pressures of the order several GPa (4–8 GPa) and at a temperature of 873 K. In this work, we have proved the feasibility of in situ powder diffraction using the Paris–Edinburgh high pressure cell for the observation of structural changes on this system and we propose modifications to improve the output of the experiment.