Influence of the surface roughness on the properties of Au films measured by surface plasmon resonance and X-ray reflectometry

Thickness and refractive index of Au films thermally evaporated onto glass substrates and with an underlayer of Cr are determined from surface plasmon resonance. The results for the thickness are found to agree very well with those from X-ray reflectivity when a simple model of layers with flat interfaces is used. Plasmon propagation along thin films is influenced by radiative damping due to scattering from surface roughness. To study this influence the surface roughness of the glass substrate, Cr an Au layers are measured by X-ray reflectometry and the results used to introduce three intermediate layers with effective refractive indices and thicknesses corresponding to the roughness. Then Fresnel's equations are used to fit the reflectivity and to deduce the layer properties. It is found that the roughness affects to a great extent the optical parameters of the Au films even when it is smaller than 1 nm. In particular, the absolute value of real part of the dielectric constant decreases while its imaginary part increases when those effects are not taken into account.     

Purification of rosmarinic acid extracts from Lavandula vera MM cell biomass

Two approaches for purification of rosmarinic acid extracts, obtained from Lavandula vera MM cell biomass were investigated: adsorption on different Amberlite XAD resins and extraction with ethylacetate. Results showed that when ethylacetate extraction was used, 18.7 times higher level of purity compared to initial material was achieved. Similarly the obtained preparations from adsorption on Amberlite XAD-7 resin and elution with 80% ethanol contained 29.8% rosmarinic acid, which is 7.7 times higher purity compared to initial material. The precipitation of rosmarinic acid as Ca-rosmarinate was investigated as well. The obtained rosmarinic acid preparations were with low yield (34% of rosmarinic acid fell into sediment).     

Some possible applications of chromatic parameters to thin film optical constants determination

Abstract

Computer simulation of colour parameters of single layer coatings, transparent in the visible spectral region, is carried out with purpose of film thickness d and optical dispersion n(λ) determination. An approach for determination of characteristics of a transparent thin film from transmitted light colour coordinates is proposed. The region in which the proposed method is applicable is estimated from comparison between film characteristics obtained from the colour coordinates and envelope methods for RF deposited transparent BaTiO₃ thin films.     

Global stabilizability of an anaerobic biodegradation process via piecewise constant feedback

We consider a nonlinear model of an anaerobic digestion process with methane production. We propose a stabilizing control law involving piecewise constant feedback and study the asymptotic stability of the obtained closed‐loop system. An extremum seeking algorithm is applied to maximize the output. Numerical simulation results are also presented to illustrate the theoretical investigations.     

Anti-inflammatory activity of Devil’s claw in vitro systems and their active constituents

Cell suspension and Agrobacterium rhizogenes-transformed hairy root cultures of Devil’s claw (Harpagophytum procumbens), an African plant with high medicinal value, were cultivated in shake-flasks. A purification scheme to isolate their main active constituents (the phenylethanoid glycosides verbascoside, leucosceptoside A, β-OH-verbascoside and martynoside; structurally identified by NMR and LC–MS) was then developed, and their concentrations in the cultures were determined by UV spectrometry following HPLC separation. Preparations, extracts and the isolated phenylethanoid glycosides from the H. procumbens in vitro systems were tested on isolated murine macrophages to study their effects on nitric oxide (NO) and cytokine (TNF-α, IL-6) release and the expression of COX-1 and COX-2. They were also added to human serum to investigate their effects on the classical pathway of complement activation. The results indicate that the extracts and preparations of the in vitro systems, and pure verbascoside (their main active constituent), had strong anti-inflammatory properties, comparable to or even higher than that of pure harpagoside (a major anti-inflammatory constituent of intact Devil’s claw tubers). Thus, they have potential as new anti-inflammatory agents.     

Extracts of plant cell cultures of <Emphasis Type="Italic">Lavandula vera</Emphasis> and <Emphasis Type="Italic">Rosa damascena</Emphasis> as sources of phenolic antioxidants for use in foods

Ethanolic extracts of plant cell cultures of lavender (Lavandula vera) and rose (Rosa damascena) have been examined as potential food antioxidants. The L. vera cell extract quenched the radicals Fremy’s salt, DPPH (2,2-diphenyl-1-picrylhydrazyl radical), and ABTS^·+ (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic) radical) more efficiently than the R. damascena extract. Also the L. vera extract inhibited lipid oxidation in a methyl linoleate emulsion more efficiently than the R. damascena extract. However, the L. vera extract had a prooxidative effect on the iron-based Fenton reaction in an aqueous model system. A similar effect was observed for pure rosmarinic acid, but not for the R. damascena extract. The addition of L. vera extract to minced chicken meat reduced lipid oxidation (measured as thiobarbituric acid reactive species) and the loss of α-tocopherol during cold storage after the meat was cooked. This suggests the antioxidative properties of L. vera extracts dominate in a real food system.     

IT project management control and the Control Objectives for IT and related Technology (CobiT) framework

Motivated by scarce academic consideration of project management control frameworks, this article explores usage, value and structure of frameworks with a focus on the popular Control Objectives for IT and related Technology (CobiT) construct. We attempt to add to an empirically validated structure of internal control over IT project management by including CobiT's views on the intended domain of content. Results from the empirical survey indicate that the metrics suggested by CobiT are regarded as feasible and important by project management professionals, and are regularly used in controlling practice. Experience, regularity of significant projects and the size of the hosting organisations, however, seem to be stronger moderators of success rates than the use of a management control system with or without support of CobiT. CobiT's suggestions are of generic nature and in particular useful for programme performance management. The latent dimensions of project quality on process and activity levels were not validated and gaps to other project assessment models were identified.