Benzimidazole- and benzothiazole-quinones: excellent substrates for NAD(P)H:quinone oxidoreductase 1

A series of benzimidazole- and benzothiazole-quinones has been synthesized. The ability of these heterocyclic quinones to act as substrates for recombinant human NAD(P)H:quinone oxidoreductase (NQO1), a two-electron reductase upregulated in tumour cells, was determined. Overall, the quinones were excellent substrates for NQO1.     

Influence of interparticle interactions on the kinetics of self-assembly and mechanical strength of nanoparticulate aggregates

Computer simulations based on Discrete Element Method have been performed in order to investigate the influence of interparticle interactions on the kinetics of self-assembly and the mechanical strength of nanoparticle aggregates.Three different systems have been considered.In the first system the interaction between particles has been simulated using the JKR (Johnson,Kendall and Roberts) contact theory,while in the second and third systems the interaction between particles has been simulated using van der Waals and electrostatic forces respectively.In order to compare the mechanical behaviour of the three systems,the magnitude of the maximum attractive force between particles has been kept the same in all cases.However,the relationship between force and separation distance differs from case to case and thus,the range of the interparticle force.The results clearly indicate that as the range of the interparticle force increases,the self-assembly process is faster and the work required to produce the mechanical failure of the assemblies increases by more than one order of magnitude.     

Total synthesis of ionomycin using ring-opening strategies

[structure: see text] The total synthesis of the polyether antibiotic ionomycin, a calcium ionophore, is described. The synthesis demonstrates the utility of ring-opening methodologies as applied to the synthesis of polypropionate and deoxypolypropionate subunits, which are found in two of the four fragments in the synthesis.     

Genuine representation of brands: a new method of representing unbiased brand-by-attribute perceptions

In this study we propose a new method of representing unbiased perceptions of brands. Specifically a likelihood-based model simultaneously disentangles a major class of psychological bias affecting attribute-based perceptions, and obtains a dimensionality reduction of the problem, resulting in a two-dimensional map. Extant research, while recognizing the importance of halo effect, has mainly focused on the identification and measurement of this bias. Conversely, in this study we explicitly address how to obtain and to graphically represent genuine brand-by-attribute ratings. Our perceptual representation offers a better understanding of the idiosyncratic impact of each attribute on brands, which ultimately helps managers to delve into the nature of brand differentiation. The proposed approach is exemplified through an empirical application using the BrandAsset® Valuator scale in a high-involvement product category.