Optimization of an Alkylpolyglucoside-Based Dishwashing Detergent Formulation.

The aim of this work was to formulate and optimize the washing performance of an alkylpolyglucoside-based dishwashing detergent. The liquid detergent was formulated with five ingredients of commercial origin: anionic (linear sodium alkylbenzenesulfonate and sodium laurylethersulfate), nonionic (C12–C14 alkylpolyglucoside) and zwitterionic (a fatty acid amide derivative with a betaine structure) surfactants, and NaCl for viscosity control. In addition to the plate test, other properties were investigated including ‘‘cloud point’’, viscosity, and emulsion stability. Statistical analysis software was used to generate a central composite experimental design. Then, a second order design and analysis of experiments approach, known as the Response Surface Methodology, was set up to investigate the effects of the five components of the formulation on the studied properties in the region covering plausible component ranges. The method proved to be efficient for locating the domains of concentrations where the desired properties were met

Cantor type functions in non-integer bases

Cantor's ternary function is generalized to arbitrary base-change functions in non-integer bases. Some of them share the curious properties of Cantor's function, while others behave quite differently

Geometric Approach to Pontryagin's Maximum Principle

Since the second half of the 20th century, Pontryagin's Maximum Principle has been widely discussed and used as a method to solve optimal control problems in medicine, robotics, finance, engineering, astronomy. Here, we focus on the proof and on the understanding of this Principle, using as much geometric ideas and geometric tools as possible. This approach provides a better and clearer understanding of the Principle and, in particular, of the role of the abnormal extremals. These extremals are interesting because they do not depend on the cost function, but only on the control system. Moreover, they were discarded as solutions until the nineties, when examples of strict abnormal optimal curves were found. In order to give a detailed exposition of the proof, the paper is mostly self\textendash{}contained, which forces us to consider different areas in mathematics such as algebra, analysis, geometry.Comment: Final version. Minors changes have been made. 56 page

Conditioned Pain Modulation Is Associated with Common Polymorphisms in the Serotonin Transporter Gene

BACKGROUND: Variation in the serotonin transporter (5-HTT) gene (SLC6A4) has been shown to influence a wide range of affective processes. Low 5-HTT gene-expression has also been suggested to increase the risk of chronic pain. Conditioned pain modulation (CPM)--i.e. 'pain inhibits pain'--is impaired in chronic pain states and, reciprocally, aberrations of CPM may predict the development of chronic pain. Therefore we hypothesized that a common variation in the SLC6A4 is associated with inter-individual variation in CPM. Forty-five healthy subjects recruited on the basis of tri-allelic 5-HTTLPR genotype, with inferred high or low 5-HTT-expression, were included in a double-blind study. A submaximal-effort tourniquet test was used to provide a standardized degree of conditioning ischemic pain. Individualized noxious heat and pressure pain thresholds (PPTs) were used as subjective test-modalities and the nociceptive flexion reflex (NFR) was used to provide an objective neurophysiological window into spinal processing. RESULTS: The low, as compared to the high, 5-HTT-expressing group exhibited significantly reduced CPM-mediated pain inhibition for PPTs (p = 0.02) and heat-pain (p = 0.02). The CPM-mediated inhibition of the NFR, gauged by increases in NFR-threshold, did not differ significantly between groups (p = 0.75). Inhibition of PPTs and heat-pain were correlated (Spearman's rho = 0.35, p = 0.02), whereas the NFR-threshold increase was not significantly correlated with degree of inhibition of these subjectively reported modalities. CONCLUSIONS: Our results demonstrate the involvement of the tri-allelic 5-HTTLPR genotype in explaining clinically relevant inter-individual differences in pain perception and regulation. Our results also illustrate that shifts in NFR-thresholds do not necessarily correlate to the modulation of experienced pain. We discuss various possible mechanisms underlying these findings and suggest a role of regulation of 5-HT receptors along the neuraxis as a function of differential 5-HTT-expression

Modification des équations d'état pour une meilleure prédiction des propriétés thermodynamiques des pétroles bruts

International audienceCe travail consiste à proposer deux modifications des équations d'état cubiques pour une meilleure prédiction des propriétés thermodynamiques des pétroles bruts. L'élaboration de ces nouvelles équations d'état est basée sur deux approches alternatives. La première approche a consisté à représenter le paramètre Alpha des équations d'état cubiques selon une forme généralisée. Dans la seconde approche, ce même paramètre Alpha a été modifié selon une procédure similaire à celle adoptée par Soave (1993). Les équations d'état établies à partir des données des propriétés des n-alcanes se sont avérées efficaces dans la prédiction des propriétés thermodynamiques d'autres familles d'hydrocarbures. L'application de ces équations d'état aux mélanges et aux fractions pétrolières a donné des résultats très satisfaisants comparativement aux autres équations d'état de la littérature

Modification des équations d'état pour une meilleure prédiction des propriétés thermodynamiques des pétroles bruts

Ce travail consiste à proposer deux modifications des équations d'état cubiques pour une meilleure prédiction des propriétés thermodynamiques des pétroles bruts. L'élaboration de ces nouvelles équations d'état est basée sur deux approches alternatives. La première approche a consisté à représenter le paramètre Alpha des équations d'état cubiques selon une forme généralisée. Dans la seconde approche, ce même paramètre Alpha a été modifié selon une procédure similaire à celle adoptée par Soave (1993). Les équations d'état établies à partir des données des propriétés des n-alcanes se sont avérées efficaces dans la prédiction des propriétés thermodynamiques d'autres familles d'hydrocarbures. L'application de ces équations d'état aux mélanges et aux fractions pétrolières a donné des résultats très satisfaisants comparativement aux autres équations d'état de la littérature

Group-Contribution Estimation of the Critical Properties of Hydrocarbons

A groupcontribution method was developed to predict critical tempertaures, pressures and volumes of hydrocarbon compounds. The method was tested with satisfactory accuracy. The absolute average deviations obtained between experimental and calculated values are 0.36%, 4.6% and 1.7% respectively for critical temperature, critical pressure and critical volume

A New Group-Contribution Method for the Estimation of Physical Properties of Hydrocarbons

In the present work, we propose a new group-contribution method to estimate the boiling point, freezing point and the liquid density at 20°C of hydrocarbons. The method was tested with satisfactory accuracy, and when compared with other group-contribution methods, it reveals better results in terms of average standard deviations

Prédiction des tensions superficielles, facteurs acentriques et indices de corrélation des hydrocarbures purs

'Une nouvelle méthode de contribution de groupes pour l'estimation des tensions superficielles, facteurs acentriques et indices de corrélation des hydrocarbures purs a été établie. Les déviations absolues moyennes (average absolute deviations, AAD) enregistrées entre les valeurs tabulées et celles calculées sont de 2,5 %, 4,1 % et 1,5 % respectivement pour les tensions superficielles, les facteurs acentriques et les indices de corrélation