Effect of rosehip extraction process on oil and defatted meal physicochemical properties

The physicochemical properties of oil from Rosa affinis rubiginosa seeds were analyzed after extraction by (i) organic solvent, (ii) cold pressing, and (iii) cold pressing assisted by enzymatic pretreatment using a mixture of the Novo-Nordisk A/S products Cellubrix (cellulase and hemicellulase activities) and Olivex (pectinase, cellulase, and hemicellulase activities). There were no significant differences in oil quality parameters, such as iodine value, refractive index, saponification value, unsaponifiable matter, and FA profile, when applying any of the three extraction processes. Although significant variations were observed in FFA content (acid value) and PV of the oil obtained by both of the cold-pressing oil extraction processes, these results were lower than the maximum value established from the Codex Alimentarius Commission. All-trans-retinoic acid content improved by 700% in rosehip oil obtained through cold pressing, with and without enzymatic pretreatment, in comparison with organic solvent extraction. This result is quite important for cosmetic oil because all-trans-retinoic acid is the main bioactive component responsible for the regenerative properties of this oil.     

Multidimensional statistical analysis of the parameterization of a genetic algorithm for the optimal ordering of tables

The optimal table row and column ordering can reveal useful patterns to improve reading and interpretation. Recently, genetic algorithms using standard crossover and mutation operators have been proposed to tackle this problem. In this paper, we carry out an experimental study that adds to this genetic algorithm crossover and mutation operators specially designed to deal with permutations and includes other parameters (initialization, replacement policy, mutation and crossover rates and stopping criteria) not examined in previous works. A proper analysis of the results must take into account all the parameters simultaneously, since the wrong conclusions can be drawn by studying each separately from the others. This is why we propose a framework for a multidimensional analysis of the results. This includes multiple hypothesis testing and a regression tree that builds a parsimonious and predictive model of the suitable configurations of the parameters.     

Cluster methods for assessing research performance: exploring Spanish computer science

The objective of this paper is to propose a cluster analysis methodology for measuring the performance of research activities in terms of productivity, visibility, quality, prestige and international collaboration. The proposed methodology is based on bibliometric techniques and permits a robust multi-dimensional cluster analysis at different levels. The main goal is to form different clusters, maximizing within-cluster homogeneity and between-cluster heterogeneity. The cluster analysis methodology has been applied to the Spanish public universities and their academic staff in the computer science area. Results show that Spanish public universities fall into four different clusters, whereas academic staff belong into six different clusters. Each cluster is interpreted as providing a characterization of research activity by universities and academic staff, identifying both their strengths and weaknesses. The resulting clusters could have potential implications on research policy, proposing collaborations and alliances among universities, supporting institutions in the processes of strategic planning, and verifying the effectiveness of research policies, among others.     

Impact of the addition of resistant starch from modified pea starch on dough and bread performance

The interest in the use of resistant starch (RS) for the development of new bakery products has significantly increased due to its ascribed physiological effects with proven health benefits. The objective of the present work was to analyse the effects of the wheat flour substitution by modified pea starch with high level of RS (PeaP) on breadmaking performance. The effects of PeaP on wheat dough functionality were evaluated by mixing/overmixing properties, texture profile analysis, viscometric profile and thermal properties. Bread quality was evaluated by physico-chemical parameters, crumb texture profile, digital image analysis, nutritional parameters and sensory evaluation. Flour substitution by PeaP up to 20% allowed keeping mechanical, extensional and viscometric parameters without significant hindering of dough machinability. Overdose of modified pea starch (30%) negatively affects dough mixing and overmixing behaviour. As a functional/prebiotic fibre, PeaP addition up to 10–20% of flour replacement entitles the formulation of wheat bread allowing a significant increase in the RS level (from 0.70 to 5.10%), delay/decrease in amylopectin retrogradation, with acceptable changes in bread quality up to 10–20% of flour replacement.     

Poly(urethanes) containing silarylene and/or germarylene units

A series of 10 poly(urethanes) were synthesized by solution polymerization from bis(chloroformates) and aromatic diamines, containing both silicon or germanium as central atom. So, the polymers prepared contain two silicon atoms or two germanium atoms exclusively or combinations of both. Me, Et, and Ph groups were bonded to the central atoms according to the nature of the monomers employed. Poly(urethanes) were characterized by FTIR, ¹H, ¹³C, and ²⁹Si NMR spectroscopy and the results agreed with the proposed structures. Additionally, intrinsic viscosity values were established in DMSO solutions and thermal analyses were developed. In all cases, thermostable oligomers were obtained, which showed a degradation process beginning at ∼240–260°C. Polymers showed a thermal dependence with the nature of the heteroatom employed. Thus, in general, when germanium was used as central atom, the thermal stability was higher than the polymers containing silicon which agrees with the lower polarity and higher energy of the C Ge bond in comparison with the C Si one. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.     

A New "Incipient-Wetness" Method for the Synthesis of Chemically Stabilized β-Cristobalite

A new "incipient-wetness" method is proposed for the synthesis of chemically stabilized β-cristobalite (CSC) that avoids the need to handle liquid phases as required by the sol-gel routes proposed in the literature. Stoichiometric compounds with the composition Si_1–xAl_*xCa_1/2O₂ have been investigated. ×= 0.07 represents the optimal composition for obtaining an extremely well-crystallized material consisting of a single β-cristobalite phase. XRD, FTIR, DSC, and differential dilatometry have been used for the physicochemical characterization of the samples.     

Multiaccess quantum channels

Shared communication channels are subject to multiple-access interference. Transmitter and receiver design techniques that explicitly deal with this interference have been shown to improve substantially the performance of communication systems over radio-frequency and other "classical" channels. Quantum multiple-access communication channels, on the other hand, have received comparatively little attention. In this paper, an input-output model for multiple-access quantum channels relevant to optical communications is proposed. The model accounts for multiaccess interference, signal attenuation, and random noise, and can be used in the analysis and design of communication systems. Using a result from optimization, a perturbation method is developed to find the minimum achievable error probability in small-interference channels. It is shown that the quantum measurement that minimizes the error probability in a no-interference channel is robust in the presence of small multiaccess interference. The results are illustrated with numerical examples, which show that optimal quantum detectors can significantly outperform conventional detectors even for moderate levels of crosstalk.     

Experimental Study of a Pilot Plant Deasphalting Process in Ethanol Sub and Supercritical Phase

The authors aimed to study the deasphalting process on laboratory scale through the design and development of a subcritical and supercritical extraction experimental unit. The experimental unity used in tests is composed by a pump, an extractor with useful volume of 3 L and one separator vessel. Extractions in sub- and supercritical conditions were carried out using petroleum residue (vacuum residuum) as feedstock and ethylic alcohol as solvent. Temperature and pressure were manipulated in order to maintain the solvent in the required conditions, thus facilitating the extraction process and avoiding sharp changes in the system. In both phases, the products in the deasphalted oil stream present adequate characteristics for the production of lubricant oils and those in the asphalt residue stream present an elevated concentration of asphalt molecules.