Conceptual graph-based knowledge representation for supporting reasoning in African traditional medicine

Although African patients use both conventional or modern and traditional healthcare simultaneously, it has been proven that 80% of people rely on African traditional medicine (ATM). ATM includes medical activities stemming from practices, customs and traditions which were integral to the distinctive African cultures. It is based mainly on the oral transfer of knowledge, with the risk of losing critical knowledge. Moreover, practices differ according to the regions and the availability of medicinal plants. Therefore, it is necessary to compile tacit, disseminated and complex knowledge from various Tradi-Practitioners (TP) in order to determine interesting patterns for treating a given disease. Knowledge engineering methods for traditional medicine are useful to model suitably complex information needs, formalize knowledge of domain experts and highlight the effective practices for their integration to conventional medicine. The work described in this paper presents an approach which addresses two issues. First it aims at proposing a formal representation model of ATM knowledge and practices to facilitate their sharing and reusing. Then, it aims at providing a visual reasoning mechanism for selecting best available procedures and medicinal plants to treat diseases. The approach is based on the use of the Delphi method for capturing knowledge from various experts which necessitate reaching a consensus. Conceptual graph formalism is used to model ATM knowledge with visual reasoning capabilities and processes. The nested conceptual graphs are used to visually express the semantic meaning of Computational Tree Logic (CTL) constructs that are useful for formal specification of temporal properties of ATM domain knowledge. Our approach presents the advantage of mitigating knowledge loss with conceptual development assistance to improve the quality of ATM care (medical diagnosis and therapeutics), but also patient safety (drug monitoring).     

Stability and 2,4-dinitrotoluene response of organic field effect transistors based on π-conjugated thiophene oligomers

This paper reports on organic field effect transistors (OFETs) based on two π-conjugated oligomers derived from thiophenes and their use as sensors for the detection of 2,4-dinitrotoluene (DNT). The detection mechanism relies on donor-acceptor interactions between the π-conjugated system (donor) and the nitrated molecule (acceptor). An important feature of sensors is the stability under operation, so, a large part of this work will be dealing with the behavior of OFETs under bias stress experiments as well as with the influence of temperature during operation. Most of results reported here are concerning hexyl capped tetra Thienylene–Vinylene (denominated 4-TV). Some preliminary results on the promising hexyl capped quinquethiophene derived from 3,4-ethylenedioxythiophene (denominated TETET) are also reported. Under a DNT contaminated air atmosphere ( 7 ppm), 4-TV based OFETs exhibit an increase of the drain current when DNT is present in the atmosphere as expected.     

Enhanced two-antenna structures for universal mobile telecommunications system diversity terminals

The design of several universal mobile telecommunications system multi-antenna systems with radiators having a high isolation, a high total efficiency and a low envelope correlation is presented. First, two planar inverted-F antennas (PIFAs), closely positioned at the top edge of a small ground plane whose size is representative of the printed circuit board of a mobile phone, are described. A technical solution is then proposed to increase the isolation between the antennas and enhance their total efficiency when still keeping them closely spaced. The technical solution is based on an optimal neutralisation technique, applied between the antennas of the structure. Several optimal systems, based on different parameters, are fabricated and measured. The simulated and measured S-parameters are presented in addition to the gain radiation patterns, the surface currents on the structure and the theoretical and experimental total efficiencies. The envelope correlation coefficients are also computed using two different equations. It is then demonstrated that, with the help of the neutralisation technique, a system composed of two closely spaced PIFAs located at the top edge of a small ground plane can lead to a high total efficiency and a low envelope correlation coefficient. In conclusion, this technique can be easily implemented at the terminal side of a wireless link and may enhance its diversity gain and multiple input multiple output performance.     

Dendritic chelating agents. 2. U(VI) binding to poly(amidoamine) and poly(propyleneimine) dendrimers in aqueous solutions

Chelating agents are widely employed in many separation processes used to recover uranyl [U(VI)] from contaminated aqueous solutions. This article describes an experimental investigation of the binding of U(VI) to poly(amidoamine) [PAMAM] and poly(propyleneimine) [PPI] dendrimers in aqueous solutions. We combine fluorescence spectroscopy with bench scale ultrafiltration experiments to measure the extent of binding and fractional binding of U(VI) in aqueous solutions of these dendrimers as a function of (i) metal-ion dendrimer loading, (ii) dendrimer generation, (iii) dendrimer core and terminal group chemistry, and (iv) solution pH and competing ligands (NO3-, PO4(3-), CO3(2-), and Cl-). The overall results of this study suggest that uranyl binding to PAMAM and PPI dendrimers in aqueous solutions involves the coordination of the UO2(2+) ions with the dendrimer amine, amide, and carboxylic groups. We find significant binding of U(VI) to PAMAM dendrimers in (i) acidic solutions containing up to 1.0 M HNO3 and H3PO4 and (ii) in basic solutions containing up to 0.5 M Na2CO3. However, no binding of U(VI) by PAMAM dendrimers is observed in aqueous solutions containing 1.0 M NaCl at pH 3.0. These results strongly suggest that PAMAM and PPI dendrimers can serve as high capacity and selective chelating ligands for U(VI) in aqueous solutions.     

Dendrimer enhanced ultrafiltration. 1. Recovery of Cu(II) from aqueous solutions using PAMAM dendrimers with ethylene diamine core and terminal NH2 groups

This article discusses the feasibility of using dendrimer enhanced ultrafiltration (DEUF)to recover Cu(II) from aqueous solutions. Building upon the results of fundamental investigations of Cu(II) binding to PAMAM dendrimers with ethylenediamine (EDA) core and terminal NH2 groups, we combine (i) dead-end ultrafiltration (UF) experiments with (ii) atomic force microscopy (AFM) characterization of membrane fouling to assess the feasibility of using DEUF to recover Cu(II) from aqueous solutions. On a mass basis, the Cu(II) binding capacities of the EDA core PAMAM dendrimers are much larger and more sensitive to solution pH than those of linear polymers with amine groups. The dendrimer-Cu(II) complexes can be efficiently separated from aqueous solutions by ultrafiltration. The metal ion laden dendrimers can be regenerated by decreasing the solution pH to 4.0; thus enabling the recovery of the bound Cu(II) ions and recycling of the dendrimers. The UF measurements and AFM characterization studies show that EDA core PAMAM dendrimers with terminal NH2 groups have very lowtendency to foul the commercially available regenerated cellulose (RC) membranes evaluated in this study. The overall results of these experiments suggest that DEUF is a promising process for recovering metal ions such as Cu(II) from aqueous solutions.     

Sampling of French local networks and applications

In this paper the authors describe a study in progress by which it is intended to represent all the French local telephone networks by just a small number of typical cases. The objectives are firstly, to gain a better knowledge of the existing network and secondly, to be able to compare equipment policies by simulating the evolution of the sample networks. The representative areas were chosen by original data analysis methods (principal component analysis followed by classification and choice of samples). Detailed data appertaining to the sample areas were then collected. They give examples of overall statistical results extrapolated at national level and discuss the corresponding applications. Lastly, they consider further developments of the study.     

A Loss-Minimization DTC Scheme for EV Induction Motors

This paper proposes a strategy to minimize the losses of an induction motor propelling an electric vehicle (EV). The proposed control strategy, which is based on a direct flux and torque control scheme, utilizes the stator flux as a control variable, and the flux level is selected in accordance with the torque demand of the EV to achieve the efficiency-optimized drive performance. Moreover, among EV's motor electric propulsion features, the energy efficiency is a basic characteristic that is influenced by vehicle dynamics and system architecture. For this reason, the EV dynamics are taken into account. Simulation tests have been carried out on a 1.1-kW EV induction motor drive to evaluate the consistency and the performance of the proposed control approach     

Optimal joint selective imperfect maintenance and multiple repairpersons assignment strategy for complex multicomponent systems

This paper addresses the joint selective maintenance and repairperson assignment problem (JSM–RAP) for complex multicomponent systems. The systems perform consecutive missions separated by scheduled finite duration breaks and are imperfectly maintained during the breaks. Current selective maintenance (SM) models usually assume that only one repair channel is available or that the repairperson assignment optimisation can be done at a subsequent stage. Using a generalised reliability function for k-out-of-n systems, we formulate the JSM–RAP for multicomponent systems more complex than the series-parallel systems commonly used in previous SM models. Two nonlinear formulations and their corresponding binary integer programming models are then proposed and optimally solved. Numerical experiments show the added value of the proposed approach and highlight the benefit of jointly carrying out the selection of the components to be maintained, the maintenance level to be performed and the assignment of the maintenance tasks to repairpersons. It is also shown that the flexibility provided by mixed skill cohorts of repairpersons over uniform cohorts can yield higher performance levels when the skillsets are significantly different.     

Dendritic anion hosts: perchlorate uptake by G5-NH2 poly(propyleneimine) dendrimer in water and model electrolyte solutions

Perchlorate (ClO4-) has emerged as a major groundwater and surface water contaminant in the United States. Ion exchange (IX) is the most widely used technology for treating water containing lower concentrations of perchlorate (<100 ppb). However, a major drawback of IX is the need for frequent regeneration or disposal of the perchlorate-laden resins. As a first step toward the development of high-capacity, selective and recyclable dendritic ligandsforthe recovery of perchloratefrom aqueous solutions by dendrimer filtration, we tested the hypothesis that dendrimers with hydrophobic cavities and positively charged internal groups should selectively bind ClO4- over more hydrophilic anions such as Cl-, NO3-, SO4(2-), and HCO3-. We measured the uptake of ClO4- by the fifth generation (G5-NH2) poly(propyleneimine) (PPI) dendrimer with a diaminobutane core and terminal NH2 groups in deonized water and model electrolyte solutions as a function of (i) anion-dendrimer loading, (ii) solution pH, (iii) background electrolyte concentration, and (iv) reaction time. The ClO4- binding capacity of this dendrimer is comparable to those of perchlorate-selective IX resins. However, its ClO4- binding kinetics is faster and reaches equilibrium in approximately 1 h. Note also that only a high pH (approximately 9.0) aqueous solution is needed to release more than 90% of the bound ClO4- anions by deprotonation of the dendrimer tertiary amine groups. The overall results of this study suggest that dendritic macromolecules such as the G5-PPI NH2 dendrimer provide ideal building blocks for the development of high-capacity, selective and recyclable ligands for the recovery of anions such as perchlorate from aqueous solutions by dendrimer enhanced filtration.