Composition of essential oil and biological activity of extracts of Viola odorata L. from central Iran

Essential oil composition of the leaves of Viola odorata L. growing wild in Kashan, central Iran, was extracted by hydro distillation-solvent extraction method and analysed using GC-MS technique. The analysis revealed the presence of 25 identified compounds, representing 92.77% of the oil with butyl-2-ethylhexylphthalate (30.10%) and 5,6,7,7a-tetrahydro-4,4,7a-trimethyl-2(4H)-benzofuranone (12.03%) being the two main components. Several components were identified for the first time in this chemotype of V. odorata. Antioxidant and antibacterial activities of the oil, methanol and chloroform extracts were also evaluated for the first time in this research work.     

In vitro bioactivity of essential oils and methanol extracts of Salvia reuterana from Iran

The chemical composition of the essential oils, antioxidant activity (DPPH and beta-carotene/linoleic acid assays) and total phenolic content (Foline-Ciocalteu) of the flowers and leaves of Salvia reuterana were determined. Essential oils extracted from the flowers and leaves by hydrodistillation were analyzed by GC and GC/MS. Forty-four constituents, representing 99.7-99.9% of the oils, were identified. The major components were germacrene D, benzoic acid hexyl ester, bicyclogermacrene, beta-gurjunene and ishwarene, constituting 33.7-31.9% of the oils. The highest radical-scavenging activity (DPPH test) was shown by the methanol extract of the flowers (IC50 = 77.6 microg/mL). In the beta-carotene/linoleic acid assay, the methanol extract of the leaves showed the highest inhibition (40.3%) which was only slightly lower than that shown by BHT (82.9%). The total phenolic contents of the methanol extracts of the flowers and leaves as gallic acid equivalents were 81.4 and 88.3 microg/mg, respectively. The plant also showed good antimicrobial activity against three strains of tested microorganisms.     

Optimal transfer pricing schemes for work averse division managers with private information

This paper models a decentralized firm under information asymmetry and effort disutility on the part of managers. We assume that managers choose efforts before observing some private information. However, after the effort choice managers receive private information on their cost parameters which they report to the headquarters. There exist many situations in which managers need to take efforts before obtaining private information; for example, the regular maintenance effort on the machine, the effort on R&D for reducing costs and the effort taken to build relationships with the supplier. Two models are considered in this paper based on the timing of acquisition of private information by the managers. We derive optimal coordination mechanisms to facilitate internal transactions for the models. The equilibrium outcome of this paper suggests that: 1) regardless of the timing of managers' information acquisition, the optimal output level under asymmetric information can have overproduction or underproduction when compared with the full information optimal output; 2) under certain demand conditions managers cannot receive any information rent benefit for their private information even if they have the option to renege on the contract after obtaining their private information.     

Protein‐oligosaccharide conjugates as novel prebiotics

Maintaining a good proportion of gut probiotic bacteria is imperative to health. This may be achieved by consuming “prebiotics,” e.g., galacto‐oligosaccharides (GOS) that selectively promote probiotic bacteria, as they often uniquely express transporters for such oligosaccharides. Proteins are an important source for amino acids essential to probiotic bacteria. As most protein digestion products are absorbed in the small intestine, and there is great competition on the residuals by colonic bacteria, amino acids are scarce (<0.01 mM) in the colonic intercellular fluid, thus limiting probiotics' proliferation. However, no existing prebiotic product contains protein. Herein, we propose a new type of prebiotics: protein‐oligosaccharide conjugates. These conjugates were designed to be selectively targeted to probiotic bacteria in the colon, for enhancing their competitive advantage over undesired microorganisms. The approach was inspired by active targeting of chemotherapy, achieved by conjugating drugs to ligands, which selectively bind to proteins uniquely expressed on cancer cells; except here, we aimed to promote, not eliminate, the targeted cells. We formed these conjugates by mild Maillard‐reaction‐based covalent conjugation of GOS to lactoferrin hydrolysate (LFH), formed by peptic digestion, hence it resists gastric digestion. LFH‐GOS conjugates comprised 76% ± 1% LFH and 25% ± 4% GOS, and self‐assembled into 0.2 to 1.5‐μm microparticles. Most of the conjugates' protein content endured simulated gastrointestinal digestion, hence is expected to reach the colon. Remarkably, we found that the growth rate of a model probiotic bacterium (Lactobacillus casei) on the conjugates was double that on the unconjugated components (0.082 and 0.041 h^?1, respectively). This study proposes the next generation of prebiotics.     

Adsorption and Desorption of Triton X-100 in Polystyrene Particles with Different Functionality

An experimental desorption study of Triton X-100 from latices with different functionality is presented. Two different strategies to follow the desorption experiment have been used: first, a discontinuous method based on the wash step (centrifugation-removal-redispersion); and second, a continuous method based on the replacement of the disperse media. The desorption results show that in all cases a residual amount of Triton X-100 remains adsorbed, indicating irreversibility of the surfactant adsorption. Finally, the effect of desorption on the colloidal stability of one type of latex-surfactant complex has been analyzed. Copyright 2000 Academic Press.     

Synthesis and characterization of ultrafine γ-Al2O3:Cr nanoparticles and their performance in antibacterial activity

Journal of Sol-Gel Science and Technology - Preventing the growth of potentially deadly bacteria by newly synthesized nanoparticles (NPs) is of great importance in the development of future drugs....     

Pulse electrodeposition of Co1−xZnx nanowire arrays: Magnetic improvement through electrolyte concentration,off-time between pulses and annealing

Using different electrolyte compositions and varying the off-time between pulses, Co_1xZn_x nanowire arrays were fabricated by ac pulse electrodeposition. The effect of deposition parameters on alloy contents was investigated by studying the microstructures and magnetic properties of as-deposited and annealed Co_1xZn_x nanowires. It is shown that Zn content in CoZn nanowires exponentially increases by increasing the zinc ions in the electrolyte. The Zn content initially increases to a maximum by increase in off-time between pulses and then falls off. Adding a certain amount of Zn to Co led to form amorphous CoZn nanowires. A significant increase in magnetization, coercivity and squareness of CoZn nanowires was observed after annealing. The rate of increase in magnetization of annealed samples was seen to be inversely proportional to their initial magnetization. Improvement of magnetic properties of annealed samples may be caused by magnetic cluster formation and pinning effect.