Complementary techniques for the characterization of thin film Ti/Nb multilayers

An aberration corrector on the probe-forming lens of a scanning TEM (STEM) equipped with an electron energy-loss spectrometer (EELS) and X-ray energy-dispersive spectrometer (XEDS) has been employed to investigate the compositional variations as a function of length scale in nanoscale Ti/Nb metallic multilayers. The composition profiles of EELS and XEDS were compared with the profiles obtained from the complementary technique of 3D atom probe tomography. At large layer widths (h≥7 nm, where h is the layer width) of Ti and Nb, XEDS composition profiles of Ti/Nb metallic multilayers are in good agreement with the EELS results. However, at reduced layer widths (h≈2 nm), profiles of EELS and atom probe exhibited similar compositional variations, whereas XEDS results have shown a marked difference. This difference in the composition profiling of the layers has been addressed with reference to the effects of beam broadening and the origin of the signals collected in these techniques. The advantage of using EELS over XEDS for these nanoscaled multilayered materials is demonstrated.     

Conformational changes of Mal d 2, a thaumatin-like apple allergen,induced by food processing

Mal d 2, a thaumatin-like protein from apple was previously described to react to almost 75% of the apple allergic patient sera. Based on the molecular structure of this protein, the present study focused on the conformational stability of Mal d 2 in relation to in vitro IgE-binding under different physico-chemical conditions and proteolysis. The structural integrity of Mal d 2 was monitored using SDS–PAGE, Western blotting using polyclonal antibodies and human sera, fluorescence spectrometry and circular dichroism. Results confirmed the stability of Mal d 2. However, Mal d 2 was reactive to human serum IgEs mainly after reduction of disulphide bridges fixing the α-helical domain II. Contrary to previous assumptions, the current findings suggest that the allergenic epitopes of Mal d 2 are hidden inside the protein structure and none of the rigorous conditions applied in industrial juice processing or digestive proteolysis enhance or reduce the binding to IgE molecules.     

Effect of NOx on AgI formation in Ag-mordenite

Ag loaded mordenite can be used as a trap for radio-iodine arising from nuclear reprocessing operations. Typically, iodine is trapped in the Ag loaded mordenite by the formation of AgI in the pores of the mordenite, through a solid-vapour reaction. In the presence of NO_x and water vapour, AgI is most likely formed by liquid-vapour reaction between AgNO₃ and I₂. This reaction results in the formation of large aggregates of AgI crystals on the surface of the mordenite, also leading to a yellow colouration of the mordenite, which is not observed when NO_x and water vapour is absent.     

A Direct Method to Calculate the Frequency and Duration of Failures for Large Networks

This paper presents a method to find the frequency and duration of outage of large complex networks through the network approach. Unreliable nodes can be considered. Numerical examples are given to elucidate the theory. The results from this technique are fairly accurate. A feature of the method is that it can handle large systems having reliable nodes with a present day computer. Even for those systems which contain unreliable nodes, the number of combinations of unreliable nodes required is much less than the number of terms needed by any path or cutset enumeration method. The use of delta-star transformations introduces some error in the results, but the error is small enough as seen from the numerical values for the examples solved in this paper.     

Preparation and characterization of multifunctional cotton fabric by coating with sonochemically synthesized zinc oxide nanoparticle-flakes and a novel approach to monitor its self-cleaning property

Multifunctional cotton fabric has been prepared by pad-dry-coating with sonochemically synthesized zinc oxide nanoparticles. The uniqueness of sonochemical synthesis is that it synthesizes without alkali at near neutral pH and hence the cotton fabric is exposed to less chemical stress. As a result of coating, the fabric shows enhanced mechanical strength, water and stain repellence, antimicrobial properties, UV-blocking capacity and self-cleaning characteristics compared to the uncoated fabric. The self-cleaning property was tested with Trypan Blue dye under sunlight. The attempt of quantifying the self-cleaning process with the rate of decolorization is a novel one. It was observed that about 69% of the colour was removed when the coated fabric was exposed to sunlight for 3 h and 30 min. The fading of colour followed pseudo-first-order kinetics.     

Homogeneous reduction of aromatic nitrocompounds by a triphenylphosphine complex of palladium

The complex Pd₂(PPh₃)₂Cl₄ has been used as a homogeneous catalyst for the reduction of C₆H₅NO₂ and p-ClC₆H₄NO₂ in basic ethanol. A reaction intermediate [Pd(PPh₃) (C₆H₅NO₂)Cl₂] has been isolated and characterised. Reduction of C₆H₅NO₂ produced aniline (75%), azobenzene (5%) and azoxybenzene (15%) under conditions of atmospheric pressure, while under conditions of high pressure the reduction product contained aniline (95%) only. The yield of p-ClC₆H₄NH₂ was highest (75%) at normal pressure and decreased with increasing pressure.     

Studies on glass-reinforced epoxy resin using either Vulkadur A or a mixture of Vulkadur A and triethanolamine as crosslinking agent

Epoxy resin can be reinforced with glass (fabric form) using Vulkadur A (a phenol formaldehyde resin containing an hardening agent) as a crosslinking agent. Overall enhancement in mechanical properties has been observed with stocks cured with a mixture of Vulkadur A and triethanolamine.     

On the phase-space dynamics of systems of spiking neurons. II: formal analysis

We begin with a brief review of the abstract dynamical system that models systems of biological neurons, introduced in the original article. We then analyze the dynamics of the system. Formal analysis of local properties of flows reveals contraction, expansion, and folding in different sections of the phase-space. The criterion for the system, set up to model a typical neocortical column, to be sensitive to initial conditions is identified. Based on physiological parameters, we then deduce that periodic orbits in the region of the phase-space corresponding to normal operational conditions in the neocortex are almost surely (with probability 1) unstable, those in the region corresponding to seizure-like conditions are almost surely stable, and trajectories in the region corresponding to normal operational conditions are almost surely sensitive to initial conditions. Next, we present a procedure that isolates all basic sets, complex sets, and attractors incrementally. Based on the two sets of results, we conclude that chaotic attractors that are potentially anisotropic play a central role in the dynamics of such systems. Finally, we examine the impact of this result on the computational nature of neocortical neuronal systems.