Rosin/acid oil-based liquid soap

Soapstock was converted into a liquid soap from its acid oil and formulated with varying amounts of rosin. The characteristics of the acid oil and rosin were experimentally estimated. Liquid soaps were characterized by density, pH, total fatty matter, free caustic alkali, critical micelle concentration, foaming capacity, wetting power, and washing performance. The foaming results indicated that the liquid soap is best used as an ingredient in a washing-machine detergent. The dark aspect of a formulation with 10% rosin precluded higher substitution.     

Co-evolution and information signals in biological sequences

The information content of a pool of sequences has been defined in information theory through enthropic measures aimed to capture the amount of variability within sequences. When dealing with biological sequences coding for proteins, a first approach is to align these sequences to estimate the probability of each amino-acid to occur within alignment positions and to combine these values through an “entropy” function whose minimum corresponds to the case where for each position, each amino-acid has the same probability to occur. This model is too restrictive when the purpose is to evaluate sequence constraints that have to be conserved to maintain the function of the proteins under random mutations. In fact, co-evolution of amino-acids appearing in pairs or tuplets of positions in sequences constitutes a fine signal of important structural, functional and mechanical information for protein families. It is clear that classical information theory should be revisited when applied to biological data. A large number of approaches to co-evolution of biological sequences have been developed in the last decade. We present a few of them, discuss their limitations and some related questions, like the generation of random structures to validate predictions based on co-evolution, which appear crucial for new advances in structural bioinformatics.     

Effect of sample’s length on flow properties of open-cell metal foam and pressure-drop correlations

Many applications require fluid flow through the open pores of metal foam. The foam is usually treated as a porous medium for which the Darcy law and the Hazen-Dupuit-Darcy (or Forchheimer) equation are used to describe the pressure drop, and for obtaining the two important flow properties, i.e., the permeability and the form drag coefficient. Little or no attention is paid to the length (or thickness) of the porous medium in the flow direction. This paper establishes a minimum length necessary for the foam to have length-independent (or bulk) permeability and form drag coefficient. This minimum length is obtained experimentally for various types of open-cell aluminum foam subjected to airflow in the Forchheimer regime. Below this thickness values of the two key flow properties are not constant, and they include entrance/exit effects, which may explain some of the discrepancies in the reported values in the literature. The Forchheimer equation was recast in two different manners, which resulted in new non-dimensional numbers- one representing the form drag and the other the viscous drag. These numbers correlated very well with the thickness of the porous medium. The obtained correlations allow for determining the pressure drop given only the velocity and the thickness of an aluminum foam sample.     

An invariant observer for a chemostat model

In this paper, we tackle the problem of designing an invariant observer for a chemostat model with adjustable and robust convergence. The main idea of the paper is to build a new class of observers for chemostat model using hidden symmetries. The effectiveness of the proposed observer is shown through simulations.     

CAD modeling of coplanar waveguide (CPW) air-bridges

In this paper, first, a comprehensive review of existing models for the coplanar waveguide (CPW) air-bridge is presented. Then, a new CAD model is proposed, in which the bridge is modeled as a small section of a microshield line, whose characteristics are obtained using the conformal mapping technique. Our results are in good agreement with full-wave results.     

Full‐wave analysis of circular guiding structures using the finite difference frequency domain method

In this article, a general full‐wave two dimensional finite difference frequency domain (2D‐FDFD) method is presented that could be used to analyze general circular multi‐layered multi‐conductor guiding structures. The FDFD method is mainly used to get the dispersion curves for these structures. The results which are obtained using the FDFD equations come through solving an eigen‐value problem, where the obtained eigen‐values and eigen‐vectors are used to produce the propagation constants, distribution of the fields and the characteristic impedances for these structures. Several examples ranging from simple coaxial lines to coupled circular microstrip lines are presented. The FDFD results are compared with those obtained through other analytical and numerical techniques. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

Aorto-coronary bypass

OBJECTIVES: Saphenous grafts used for coronary artery bypass are classically dissected via a continuous incision of the leg, the thigh or both. Recently, a new video-surgery technique has been introduced in an attempt to reduce the trauma of saphenous vein dissection. The aim of this work was to evaluate the possible benefits of this new technique compared with classical dissection. PATIENTS AND METHODS: Sixty patients requiring coronary artery bypass grafts were included in this study and randomly divided into two groups. In group I (30 patients) the saphenous vein was dissected according to the classical technique. The video-surgery technique was used for the other 30 patients in group II. The two groups were not significantly different for mean age, sex ratio, or history of diabetes or lower limb arteriopathy. The same number of bypasses was performed in both groups (2.6 +/- 0.7). Outcome was compared for: dissection related complications (hematomas, infections), length of the skin incision over the length of the dissected vein, duration of the dissection procedure, and post-operative pain. RESULTS: A leg incision was used in 28 cases out of 30 cases in both groups. The length of the saphenous vein dissected was 27.6 cm in group I and 21.8 cm in group II. The length of the skin incision was 27 cm in group I and only 4.7 cm in the video-surgery group II, giving an incision/vein ratio of 97% and 21% respectively. Operative time was however 37.9 min for group I and 48.5 min for group II. There was no significant difference between the groups for hematoma formation or infection but the patients in the video-surgery group experienced less post-operative pain. CONCLUSION: Besides an improvement in the esthetic result, video-surgery dissection of the saphenous vein reduces post-operative pain at the cost of a slightly longer operative procedure.