Application of Delphi method in selection of procurement systems for construction projects

A number of procurement selection systems have been developed over the last decade. The use of multi-attribute decision analysis has been considered the foremost technique for examining client needs and the weightings of preferences from experts for each procurement system in the most objective way available. However, the major difficulty of these selection models lies in the lack of consensus among the experts on the utility factor of the selection criteria. To overcome these deficiencies, a Delphi technique was adopted to develop a multi-attribute model. Four rounds of Delphi surveys were conducted. A statistically significant consensus on the weighting of the utility factors for each procurement system was obtained from eight experts. The results vividly reveal that the Delphi method is a powerful and appropriate technique for deriving objective opinions in a rather subjective area such as the multi-attribute model for the selection of procurement system.     

Influence of soluble and insoluble cyclodextrin polymers on drug release from hydroxypropyl methylcellulose tablets

Background: The influence of β-cyclodextrin (β-CD) polymers on drug release from hydroxypropyl methylcellulose (HPMC) matrices has not been reported in the literature. Aim: The influence of monomeric β-CD and both soluble and insoluble β‐CD polymers on drug release from tablets containing either 30% or 50% hydroxypropyl methylcellulose has been studied using diflunisal (DF) as model drug. Method: The DF-β-CD inclusion complex (1:1 M) was prepared by coevaporation and characterised using X-ray diffraction, differential thermal analysis, and IR spectroscopy. The dissolution assays were performed according to the USP paddle method. Results: The incorporation of β-CD in the complexed form increases drug release from hydroxypropyl methylcellulose tablets in comparison with the physical mixture because of the better solubilization of the drug. The soluble polymer promotes drug release to a higher extent than the physical mixture with monomeric β-CD, but the insoluble polymer, which is itself a hydrogel, gives rise to the most retarded release profile, probably by retention of the drug in its structure. The formulations containing physical mixtures with either β‐CD or the soluble polymer present an optimum adjustment to zero-order release kinetics, and the inclusion complex followed non-Fickian diffusion according to the Korsmeyer–Peppas model. Conclusion: The release profile of DF from a HPMC matrix can be modulated in different ways by the use of either monomeric or polymeric β-CD.     

Quantum Statistics of Stimulated Raman and Hyper-Raman Scattering of Squeezed Light with Pump Depletion

Abstract

Using the approximation of small fluctuations around a stationary solution, photon statistics and quadrature variances are derived in stimulated Raman and hyper-Raman scattering including the coupling of pumping, Stokes, anti-Stokes and phonon modes. The depletion of pump light is included. Compared to Raman scattering, additional regimes to generate anti-bunched, sub-Poisson and squeezed light were found caused by self-interaction of the pump mode. It was possible to include effects of nonlinear dynamics, initial squeezing of radiation and phonon system, external noise and losses.     

Quantum authentication with unitary coding sets

Abstract

A general class of authentication schemes for arbitrary quantum messages is proposed. The class is based on the use of sets of unitary quantum operations in both transmission and reception, and on appending a quantum tag to the quantum message used in transmission. The previous secret between partners required for any authentication is a classical key. We obtain the minimal requirements on the unitary operations that lead to a probability of failure of the scheme less than one. This failure may be caused by someone performing a unitary operation on the message in the channel between the communicating partners, or by a potential forger impersonating the transmitter.     

Effect of using Erythritol as a Sucrose Replacer in Making Spanish Muffins Incorporating Xanthan Gum

Spanish muffins are sweet, high-calorie baked products which are highly appreciated for their good taste and soft texture. The aim of this work was to evaluate the suitability of erythritol and of its combination with xanthan gum and double quantities of leavening agent for replacing sucrose in Spanish muffins and to understand their functionality in a muffin system. The linear viscoelastic properties of the batter during heating, its specific gravity and bubbles, muffin weight loss during baking and muffin bubbles, height, volume, and instrumental texture were studied. Both erythritol and sucrose increase in the temperature at which the viscoelastic functions increased with temperature. In comparison with the reduced sucrose muffins, the use of erythritol increased the number of air bubbles in the batter. The height of the muffins also increased in the presence of erythritol when compared to the corresponding reduced sucrose muffins, although the volume did not. Erythritol was not effective in diminishing the increased hardness associated with sucrose reduction, but the combination of erythritol with xanthan gum and a double quantity of leavening agent significantly improved the muffin volume (from 94 cm³ for 100% erythritol formulation to 108 cm³ for 100% erythritol–xanthan double-leavening agent formulation) and significantly decreased the hardness (from 75 N for 100% erythritol formulation to 25 N for 100% erythritol–xanthan double leavening agent formulation).     

Urinary 6-sulfatoxymelatonin and total antioxidant capacity increase after the intake of a grape juice cv. Tempranillo stabilized with HHP

Red grapes contain elevated amounts of antioxidant compounds (polyphenols) that may potentially prevent cell aging, cardiovascular disease and oxidation-related disorders. Since functional drinks are presently one of the most dynamic sectors of the market, the present work was aimed at evaluating the possible antioxidant effect of an experimental grape juice in terms of urinary 6-sulfatoxymelatonin (aMT6-s) and total antioxidant capacity in young (20 ± 10 yr-old), middle-aged (45 ± 10 yr-old) and elderly (75 ± 10 yr-old) individuals. Grapes (Vitis vinifera cv. Tempranillo) were de-stemmed, racked and pressed. The juice was subsequently stabilized by high hydrostatic pressure (HHP). Participants consumed 200 mL of grape juice twice a day (as the lunch and dinner desserts) for 5 days. First-void morning urines were collected before treatment (basal values), the day immediately after the last ingestion of juice (assay), and one day afterwards (post-assay). aMT6-s and total antioxidant capacity were quantified using commercial ELISA and colorimetric assay kits, respectively. The intake of grape juice cv. Tempranillo induced a significant increase of urinary aMT6-s and total antioxidant capacity in the three groups of age analyzed as compared to their corresponding basal and post-assay values. These functional/nutraceutical properties may be of interest for a prospective commercialization of the grape juice. The novel technology used for juice stabilization may be suitable for introducing into the market a product with high sensory and nutritional quality, as it has been shown in this study.     

Concentration of Docosahexaenoic Acid (DHA) by Selective Alcoholysis Catalyzed by Lipases

The aim of this work was to obtain acylglycerols from tuna oil (23 % weight DHA) rich in docosahexaenoic acid (DHA) by selective ethanolysis, catalyzed by lipases. First, seven immobilized lipases were tested and the best DHA concentration and recovery in the acylglycerol fraction were attained with Lipozyme TL IM^® from Thermomyces lanuginosus, Lipozyme RM IM from Rhizomucor miehei, and lipase from Thermomyces lanuginosus immobilized on Immobead 150. As it is the cheapest, Lipozyme TL IM^® was selected to optimize the reaction conditions. The influence of temperature, reaction time, and ethanol/oil and lipase/oil ratios were studied. Under the optimized conditions (35 °C, ethanol/oil molar ratio 2.3, lipase/oil ratio 5 % weight and 48 h) and for a 56 % conversion, acylglycerols were obtained with a 45 % DHA concentration and 90 % recovery. In these optimized conditions the reaction was scaled up to 766 g of tuna oil and carried out in a batch stirred tank reactor, with the lipase contained in a cartridge filter attached to the stirring rod. The results were similar to those obtained on the smaller scale. The DHA-enriched acylglycerols were separated from the ethyl esters by evaporation of the latter in a short-path vacuum distiller, where the influence of distillation temperature was studied. At 170 °C DHA-rich acylglycerols (44 % DHA) were recovered in the residue with 94.5 % purity and 72 % recovery.     

RoHS regulated substances in mixed plastics from waste electrical and electronic equipment

The disposal and recovery of plastics from waste electrical and electronic equipment (WEEE) are of considerable importance, both from an environmental and an economic perspective. This paper presents the results of a study investigating current concentrations of hazardous substances in mixed plastics from WEEE and their implications for an environmentally sound recovery. The study included 53 sampling campaigns for mixed plastics from WEEE. The samples were analyzed with regard to heavy metals (cadmium, chromium, mercury, and lead) and flame retardants (PentaBDE, OctaBDE, DecaBDE, DecaBB) regulated in the RoHS Directive. Besides these substances, other brominated flame retardants known to occur in electronics (HBCD, TBBPA) as well as the total bromine and phosphorus contents were considered. Results show that no mixed plastics fraction from WEEE is completely free from substances regulated in the RoHS Directive. The lowest number and average concentrations were found in flat screen monitors. The highest concentrations were found in mixed plastics from CRT monitors and TVs. Mixed plastics fractions with high average concentrations of heavy metals originate from the treatment of small household appliances (cadmium), ICT equipment (lead), and consumer equipment (lead). Mixed plastics fractions with high average concentrations of brominated flame retardants mainly originate from the treatment of small household appliances for high temperature applications (DecaBDE), CRT monitors (OctaBDE and DecaBDE) and consumer equipment (DecaBDE), in particular CRT TVs (DecaBDE). To avoid a dissipation of hazardous substances into plastics and the environment, it is recommended that mixed plastics from WEEE are subject to a strict quality management.     

Is the production of the biogenic amines tyramine and putrescine a species-level trait in enterococci?

Biogenic amines (BA) are toxic nitrogenous compounds that can be accumulated in foods via the microbial decarboxylation of certain amino acids. Lactic acid bacteria (LAB) strains belonging to different species and genera have been described as BA producers and are mainly responsible for their synthesis in fermented foods. It is generally accepted that the capacity to produced BAs is strain-dependent. However, the large number of enterococci identified as BA producers suggests that the aminogenic trait may be a species-level characteristic. Enterococcus faecalis, Enterococcus faecium and Enterococcus durans strains of different origin were analysed to determine their capacity to produce tyramine and putrescine. The presence of the genes responsible for this and the identity of their flanking regions were checked by PCR. The results suggest that tyramine biosynthesis is a species-level characteristic in E. faecalis, E. faecium and E. durans. Putrescine synthesis was found to be a species-level trait of E. faecalis, with production occurring via the agmatine deamination pathway. Some E. faecium strains of human origin also produced putrescine; this trait was probably acquired via horizontal gene transfer.     

Angiotensin‐converting enzyme‐inhibitory activity in protein hydrolysates from normal and anthracnose disease‐damaged Phaseolus vulgaris seeds

BACKGROUND: Bean seeds are an inexpensive source of protein. Anthracnose disease caused by the fungus Colletotrichum lindemuthianum results in serious losses in common bean (Phaseolus vulgaris L.) crops worldwide, affecting any above‐ground plant part, and protein dysfunction, inducing the synthesis of proteins that allow plants to improve their stress tolerance. The aim of this study was to evaluate the use of beans damaged by anthracnose disease as a source of peptides with angiotensin‐converting enzyme (ACE‐I)‐inhibitory activity. RESULTS: Protein concentrates from beans spoiled by anthracnose disease and from regular beans as controls were prepared by alkaline extraction and precipitation at isolelectric pH and hydrolysed using Alcalase 2.4 L. The hydrolysates from spoiled beans had ACE‐I‐inhibitory activity (IC₅₀ 0.0191 mg protein mL^?1) and were very similar to those from control beans in terms of ACE‐I inhibition, peptide electrophoretic profile and kinetics of hydrolysis. Thus preparation of hydrolysates using beans affected by anthracnose disease would allow for revalorisation of this otherwise wasted product. CONCLUSION: The present results suggest the use of spoiled bean seeds, e.g. anthracnose‐damaged beans, as an alternative for the isolation of ACE‐I‐inhibitory peptides to be further introduced as active ingredients in functional foods. © 2012 Society of Chemical Industry