Search

Introduction:: In this paper, a robust sliding mode controller is developed to control an orthosis used for rehabilitation of lower limb. Materials and Methods:: The orthosis is defined as a mechanical device intended to physically assist a human subject for the realization of his movements. It should be adapted to the human morphology, interacting in harmony with its movements, and providing the necessary efforts along the limbs to which it is attached. Results:: The application of the sliding mode control to the Shank-orthosis system shows satisfactory dynamic response and tracking performances. Conclusion:: In fact, position tracking and speed tracking errors are very small. The sliding mode controller effectively absorbs disturbance and parametric variations, hence the efficiency and robustness of our applied control.

In this work, we investigate the properties of manganese dioxide (MnO2) and graphene oxide (GO) to develop a new photoelectrochemical (PEC) sensor-based MnO2-GO heterojunction on stainless steel electrode for chemical detection of copper (Cu(II)) cation. During the PEC detection process and using chronoamperometry, the photocurrent density increases gradually with the addition of incremental Cu2+ concentration, achieving a relatively low detection limit (0.9120 µM) and a linear interval range from 0.01 to 110 µM with high selectivity and stability under neutral aqueous solution (pH 7.00). In addition, the PEC change of electrode state in presence of Cu(II) cation requires the oxidized state of MnO2-GO heterojunction; this can be reached by applying anodic potential to the electrode (E = + 0.8 V). Thus, a switchable, low-cost, regenerative, and sensitive PEC sensor based on the change of MnO2-GO heterojunction surface state permits the selective detection of copper.

The increasing of penetration of wind energy conversion system to produce electricity lead to improve the choice of the operational control strategies. This paper deals with the modeling and control design of wind turbine using Takagi-Sugeno techniques. Due to the uncertainty wind speed measured through the anemometer, a Takagi-Sugeno observer is designed to estimate the effective wind speed. The nonlinear behavior of the wind turbine is driven through the Takagi-Sugeno fuzzy model approach based on Taylor linearized model. In order to maximize the extracted energy from the wind turbine conversion system, T-S observer combined with H-infinity performance is considered. The controller design based on Linear Matrix Inequalities (LMI) is used to ensure the stability and the robustness of the model. The effectiveness of the proposed control is tested in terms of wind turbine rotational speed relative to the estimated wind speed.

Background: Saponin metabolism shows high structural variability due to the diversity of aglycones and glycosylations (Gly). Although they represent a potential source of drug design, their metabolism remains misunderstood yet due to insufficient investments in analytical methods. Aims: Bibliographic structural data offer a wide field for extensive statistical analysis, highlighting mechanistic orders governing metabolic diversity. This work presents an original simulation method based on simplex rule for highlighting regulatory mechanisms of metabolism from categorical structural data. Methods: Simulation was applied on a set of 231 saponins of the Caryophyllaceae plant family initially affiliated to four aglycone types: gypsogenin (Gyp), quillaic acid (QA), gypsogenic acid (GA), and 16-OH-gypsogenic acid (16-OH-GA). Molecules were initially characterized by relative glycosylation levels of different carbons. Simplex approach was applied by combining saponins of the four aglycone groups using a complete set of N gradual weightings between structural groups. In silico combinations were applied by randomly sampling representative saponins from the four groups conforming to their weights given by mixture design. Gly profiles of sampled saponins were averaged to calculate a barycentric molecular profile for each mixture. With N mixtures, N barycentric molecules were iteratively calculated by bootstrap, leading to smoothed data from which Gly trends between carbons were highlighted. Results: Sequential, competing and cooperative Gly trends were highlighted according to the types of aglycones, attached saccharides and positions of substituted carbons. Such various conditional Gly trends seemed to be linked to multiple factors, including steric effects, regio-selectivity, enzymatic specificity and enzymatic promiscuity. These simulated results could be helpfully useful in chemical synthesis and drug design. Conclusion: These simulated results could usefully help for chemical syntheses and drug design.

Phosphogypsum (PG) is an acidic industrial by-product, resulting from the production of phosphoric acid. In Tunisia, 10 million tons of PG are discarded yearly without any treatment. The Tunisian PG is characterized by its cadmium content of about 3.1–22.9 mg/kg. It is mainly stocked without any treatment near the production sites. Therefore, minimizing the negative impact of this waste has increasingly aroused the interest of many researchers. The use of PG as alternative phosphorous and sulfate fertilizer was envisaged. In this context, we have investigated the possibility of cultivating transgenic potato plants overexpressing the dehydration responsive element binding (StDREB1) protein on PG-supplemented substrates. Prewashed PG (WPG) was used to reduce the acidity of PG. Two WPG concentrations were used (15 and 30%) for potato culture during 60 days. The data show that WPG altered the survival rate of wild-type potato plants. Indeed, increasing the amount and treatment period of WPG led to a decrease in plant survival to 10% (after 60 days), while the survival rate of transgenic lines was about 50% with normal growth characteristics. Furthermore, an increase in proline and soluble sugar and reduced levels of H2O2 and malondialdehyde were measured in transgenic plants. An increase in antioxidant enzyme activities was observed in these transgenic lines revealing that they can cope with oxidative stress generated by phosphogypsum addition in the medium. A very low accumulation of Cd was detected in leaves of both transgenic lines. All these data suggest that overexpression of the StDREB1 transcription factor in transgenic potato plants improved their tolerance to WPG.

In wind conversion system, Doubly Fed Induction Generator is widely used. The main objective of the control of the wind system in partial load power production is to require the maximum efficiency power flow transfer to the grid. Vector control strategy is well used to achieve this purpose where the conventional control design employs PI regulators for the adjusting of the currents loops. However these regulators are sensitive to parameters variations that results the degradation in the performance of the controlling system. This paper deals with an alternative controller for the DFIG generator based on internal model control strategy which the controller selected is an approximate inverse of the model. The design control was done with 5MW NREL DFIG using SimWindFarm toolbox Matlab/Simulink and compared with the classical proportional integral control to discuss the performance in terms of tracking references and sensitivity to parameters variations.

We report on the design of a simple yet sensitive and selective electrode for amperometric determination of dopamine at a cathodic potential as low as −0.30 V vs. Ag/AgCl. The electrode was obtained by self-assembly of ω-mercaptopropyl naphthoquinone (NQ-SAM) on the surface of a polycrystalline gold electrode. The presence of dopamine induces an increase of the reduction current peak at −0.30 V corresponding to the reduction of naphthoquinone to hydronaphthoquinone. Dopamine and dopamine-quinone accumulate on the surface to form a 3D network linked by hydrogen bonds. Raman and infrared spectroscopy as well as atomic force microscopy confirmed the multilayer formation. The method allows dopamine to be indirectly detected at a working potential that is lower by 0.50 V than the standard oxidation potential at a bare gold electrode. The sensor shows distinct oxidation potentials for dopamine (120 mV), ascorbic acid (280 mV) and uric acid (520 mV) which makes the method fairly selective. The analytical range extends from 1 to 100 μM concentrations of dopamine, and the limits of detection and quantification are 0.040 and 0.134 μM, respectively.

Electrically addressed covalent immobilization of biomolecules to the defined electrodes of an electrode array is described. It is based on Michael addition of the thiol group of biomolecules to α,β-unsaturated carbonyl groups of benzoquinone. This "click" reaction was tested by immobilization of a number of thiolated compounds on the simplest array consisting of two gold electrodes coated by a self-assembled monolayer of benzoquinone-terminated hexanethiol. Electrically controlled binding of hexanethiol, ferrocenylhexanethiol, human serum albumin and thiol-terminated single-stranded DNA (ssDNA) was investigated. The binding was studied using cyclic voltammetry, X-ray photoelectron spectroscopy and surface plasmon resonance. The reaction requires the oxidized state of the benzoquinone moiety; this can be reached by applying of a moderate anodic potential to the electrode. Surface plasmon resonance measurements demonstrated that the thiol-modified ssDNA immobilized by this technique binds complementary synthetic oligonucleotides or PCR-amplified DNA fragments. The developed technology of electrical addressing of covalent immobilization can be applied for fabrication of sensor arrays.

With a large increase in wind power generation, the direct driven Permanent Magnet Synchronous Generator is the most promising technology for variable speed operation and it also fulfills the grid requirements with high efficiency. This paper studies and compares conventional based on PI controller and proposed control technique for a direct driven PMSG wind turbine. The generator model is established in the Park synchronous rotating d-q reference frame. To achieve maximum power capture, the aeroturbine is controlled through Maximum Power Point Tracking (MPPT) while the PMSG control is treated through field orientation where the two currents control loops are regulated. A proposed direct-current based d-q vector control design is designed by the integration of the Internal Model Controller. Then an optimal control is developed for integrated control of PMSG power optimization and Voltage Source Converter control. The design system was done using SimWindFarm Matlab/Simulink toolbox to evaluate the performance of conventional and proposed technique control of PMSG wind turbine. The analysis, simulation results prove the effectiveness and robustness of the proposed control strategy.

Plant growth and productivity are greatly affected by environmental stresses such as dehydration, high salinity, low temperature and pathogen infection. Plant adaptation to these environmental stresses is controlled by cascades of molecular networks. The dehydration-responsive element-binding (DREB) transcription factors play an important role in the response of plants to environmental stresses by controlling the expression of many stress-related genes. They specifically interact with C-repeat/DRE (A/GCCGAC) sequences present in the promoter regions of target genes. One of the DREB1 cDNA was previously cloned and overexpressed in transgenic potato plants. These transgenic plants displayed an improved tolerance to high salinity and drought stresses. The StDREB1 factor belongs to A-4 group that seem to be involved in biotic stress response. This report investigates the effect of Fusarium solani infection on the StDREB1 transgenic lines. Since a number of pathogenesis-related (PR) proteins are considered as DREB1 target genes, the expression of PR2, PR9 and PR3 genes were tested under biotic stress conditions. The β-1,3-glucanase (PR2) was specifically induced upon infection, whereas the chitinase and the peroxydase were expressed constitutively. The data also show that high levels of DREB1 transcripts accumulated rapidly when wild-type and transgenic plants were infected by F. solani. DREB1 transgenic potato plants accumulated higher levels of pathogenesis-related gene transcripts, such as PR2. These results showed that StDREB1 plays an important role in response to fungal attack in potato.

The ERF transcription factors belong to the AP2/ERF superfamily, one of the largest transcription factor families in plants. They play important roles in plant development processes, as well as in the response to biotic, abiotic, and hormone signaling. In the present study, 155 putative ERF transcription factor genes were identified from the potato (Solanum tuberosum) genome database, and compared with those from Arabidopsis thaliana. The StERF proteins are divided into ten phylogenetic groups. Expression analyses of five StERFs were carried out by semi-quantitative RT-PCR and compared with published RNA-seq data. These latter analyses were used to distinguish tissue-specific, biotic, and abiotic stress genes as well as hormone-responsive StERF genes. The results are of interest to better understand the role of the AP2/ERF genes in response to diverse types of stress in potatoes. A comprehensive analysis of the physiological functions and biological roles of the ERF family genes in S. tuberosum is required to understand crop stress tolerance mechanisms.

A mass conservation law-based chemometric approach was developed to extract smoothed processes governing inter- and intra-molecular variability of structural diversity in metabolic pools. The approach consisted of a machine-learning method using simplex rule to calculate a complete set of smoothed barycentric molecules from iterated linear combinations between molecular classes (glycosylation classes). An application to four glycosylation levels (GLs) of Caryophyllaceae saponins highlighted aglycone-dependent variations of glycosylations, especially for gypsogenic acid (GA) which showed high 28-glucosylation levels. Quillaic acid (QA) and gypsogenin (Gyp) showed closer variation ranges of GLs, but differed by relationships between glycosylated carbons toward different sugars. Relative GLs of carbons C3 and C28 showed associative (positive), competitive (negative) or independent (unsensitive) trends conditioned by the aglycone type (GA, Gyp) and molecular (total) GLs (the four classes): 28-glucosylation and 28-xylosylation showed negative global trends in Gyp vs GLs-depending trends in QA. Also, relative levels of 3-galactosylation and 3-xylosylation varied by unsensitive ways in Gyp vs positive trends in QA. These preliminary results revealed higher metabolic tensions (competitions) between considered glycosylations in Gyp vs more associative processes in QA. In conclusion, glycosylations of GA and QA were relatively distant whereas Gyp occupied intermediate position.

International audience; Metabolisms represent highly organized systems characterized by strong regulations satisfying the mass conservation principle. This makes a whole chemical resource to be competitively shared between several ways at both intra-and inter-molecular scales. Whole resource sharing can be statistically associated with a constant sum-unit constraint which represents the basis of simplex mixture rule. In this work, a new simplex-based simulation approach was developed to learn scaffold information on metabolic processes controlling molecular diversity from a wide set of observed chemical structures. Starting from a dataset of chemical structures classified into p clusters, a machine learning process was applied by linearly combining the p clusters j and randomly sampling a constant number (n) of molecules according to different clusters' weights (wj/w) given by Scheffé's mixture matrix. At the output of mixture design, molecular linear combinations lead to calculate barycentric molecules integrating the characteristics of the different weighted clusters. The N mixtures-design was iterated by bootstrap technique leading to extensive exploration of chemical variability between and within clusters. Finally, the K response matrices issued from K iterated mixture designs were averaged to calculate a smoothed matrix containing scaffold information on regulation processes responsible for molecular diversification at inter- and intra-molecular (atomic) scales. This matrix was used as a backbone for graphical analysis of positive and negative trends between atomic characteristics (chemical substitutions) at both mentioned scales. This new simplex approach was illustrated by cycloartane-based saponins of Astragalus genus by combining three desmosylation clusters characterized by relative glycosylation levels of different aglycones' carbons.

Metabolisms represent highly organized systems characterized by strong regulations obeying to mass conservation law. This makes a whole chemical resource to be competitively shared between several biosynthesis components (ways) at both intra-and inter-molecular scales. Statistically, the whole shared-resource principle can be considered under a constant sum-unit constraint which represents the basis of simplex mixture rule. In this work, a new simplex-based chemometric approach was developed to extract scaffold information on different biosynthesis regulation factors responsible for the chemical structural diversity at atomic and molecular scales within a large metabolic system. This approach consisted in combining different (p) molecular clusters into a complete set of N mixtures containing a same constant (n) number of molecules which were randomly sampled by gradually varying the relative weights (nj/n) of combined clusters j. The complete set of N combinations was initially given by the Scheffe’s mixture matrix. At the output of Scheffe’s design, each molecular mixture was represented by a theoretical average (barycentric) molecule which was trained by the characteristics of the different weighted clusters. The mixture design was iterated several (K) times by applying bootstrap technique leading to extensively explore chemical variability between and within clusters. Finally, the K response matrices issued from the K applications of Scheffe’s mixture design were averaged to obtain a smoothed matrix containing scaffold information on different regulation factors responsible for molecular diversification at inter- and intra- (atomic) molecular scales. This matrix was used as a backbone for graphical analysis of different positive and negative trends between atomic characteristics (chemical substitutions) at both mentioned scales. This new simplex approach was illustrated by cycloartane-based saponins of Astragalus genus by considering three desmosylation clusters (mono-, bi- and tridesmoside saponins) characterized by relative glycosylation levels of different aglycones’ carbons.

A new family of N , N -disubstituted p-anisidine-based electroactive ligands bearing dipyridinylamino- ( 1 ), difuranylamino- ( 2 ) and dithiophenylamino- ( 3 ) binding sites has been prepared by reductive alkylation of anisidine. The electrochemical investigations, in 0.1 mol/dm −3 LiClO 4 acetonitrile solution, showed that upon the addition of metallic cations, the redox features of 1 underwent drastic changes due to the cation chelation. The chemosensor complexation with Ni(II), Zn(II), Cd(II) and Pb(II) led to large anodic shifts of the oxidation potential peaks up to 700 mV depending on the metal cation. A particularly high sensitivity toward nickel(II) with a higher selectivity to zinc(II) were observed. However, in the same conditions, thiophenyl- and furfuranyl- derivatives showed no sensitivity for any of the investigated cations. Moreover, UV–visible spectroscopy studies of 1 showed that the compound can act as a chromogenic guest-responsive and in presence of metallic cations, the absorption bands of compound 1 shifted due to a participation of the nitrogen lone pairs in the cation complexation. UV–visible spectroscopy did also allow to distinguish between the Ni(II) and Zn(II) complexes. Electrochemical and UV–visible spectroscopic investigations showed that the complexes have 1:2 stoichiometry [M( 1 ) 2 ] 2+ (M: Zn, Ni, Cd and Pb).

International audience; Background. Olive oils (OOs) show high chemical variability due to several factors of genetic, environmental and anthropic types. Genetic and environmental factors are responsible for natural compositions and polymorphic diversification resulting in different varietal patterns and phenotypes. Anthropic factors, however, are at the origin of different blends' preparation leading to normative, labelled or adulterated commercial products. Control of complex OO samples requires their (i) characterization by specific markers; (ii) authentication by fingerprint patterns; and (iii) monitoring by traceability analysis.Methods. These quality control and management aims require the use of several multivariate statistical tools: specificity highlighting requires ordination methods; authentication checking calls for classification and pattern recognition methods; traceability analysis implies the use of network-based approaches able to separate or extract mixed information and memorized signals from complex matrices. Results. This chapter presents a review of different chemometrics methods applied for the control of OO variability from metabolic and physical-chemical measured characteristics. The different chemometrics methods are illustrated by different study cases on monovarietal and blended OO originated from different countries.Conclusion. Chemometrics tools offer multiple ways for quantitative evaluations and qualitative control of complex chemical variability of OO in relation to several intrinsic and extrinsic factors.

We report on the design of an amperometric tyrosinase-based biosensor using a self-assembled monolayer of ω-mercaptopropyl naphthoquinone on gold electrode as an electron mediator. Under optimal conditions (i.e. pH=7.4 and E=-0.35V vs. KCl), the chronoamperometric response of the naphthoquinone-modified bioelectrode to successive additions of phenol was evaluated. The biosensor exhibits sensitive bioelectrocatalytic response at a working potential of -0.35V vs. Ag/AgCl (sat.KCl), reaching the steady-state current within 40s after each addition of phenol solution with a range of 0-135μM and a limit of detection and quantification which are 0.019μM and 0.0633μM, respectively. The bioelectrode was used to determine the content in polyphenol in a local virgin olive oil.

It has been established that drought-responsive element binding (DREB) proteins correspond to transcription factors which play important regulatory roles in plant response to abiotic and biotic stresses. In this study, a novel cDNA encoding DREB transcription factor, designated StDREB1, was isolated from potato (Solanum tuberosum L.). This protein was classified in the A-4 group of DREB subfamily based on multiple sequence alignments and phylogenetic characterization. Semi-quantitative RT-PCR showed that StDREB1 is expressed in leaves, stems, and roots under stress conditions and it is greatly induced by NaCl, drought, low temperature, and abscisic acid (ABA) treatments. Overexpression of StDREB1 cDNA in transgenic potato plants exhibited an improved salt and drought stress tolerance in comparison to the non-transformed controls. The enhanced stress tolerance may be associated with the increase in P5CS-RNA expression (δ 1-pyrroline-5-carboxylate synthetase) and the subsequent accumulation of proline osmoprotectant in addition to a better control of water loss. Overexpression of StDREB1 also activated stress-responsive genes, such as those encoding calcium-dependent protein kinases (CDPKs), in transgenic potatoes under standard and high salt conditions. These data suggest that the StDREB1 transcription factor is involved in the regulation of salt stress tolerance in potato by the activation of different downstream gene expression.

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; Dehydration responsive element binding proteins (DREB) are members of a larger family of transcription factors, many of which have been reported to contribute to plant responses to abiotic stresses in several species. While, little is known about their role in potato (Solanum tuberosum). This report describes the cloning and characterization of a DREB transcription factor cDNA, StDREB2, isolated from potato(cv Nicola) plants submitted to salt treatment. Based on a multiple sequence alignment, this protein was classified into the A-5 group of DREB subfamily. Expression studies revealed that StDREB2 was induced in leaves, roots and stems upon various abiotic stresses and in response to exogenous treatment with abscisic acid (ABA). In agreement with this expression pattern, over-expression of StDREB2 in transgenic potato plants resulted in enhanced tolerance to salt stress. These data suggest that the isolated StDREB2 encodes a functional protein involved in plant response to different abiotic stresses. An electrophoretic mobility shift assay (EMSA) indicated that the StDREB2 protein bound specifically to the DRE core element (ACCGAGA) in vitro. Moreover, Semi quantitative RT-PCR analysis revealed that the transcript level of a putative target gene i.e. d1-pyrroline-5-carboxylate synthase (P5CS) was upregulated in transgenic plants submitted to salt stress conditions. A concomitant increase in proline accumulation was also observed under these conditions. Taking together, all these data suggest that StDREB2 takes part in the processes underlying plant responses to abiotic stresses probably via the regulation of ABA hormone signaling and through a mechanism allowing proline synthesis.

International audience; Leberagin-C, a new member of the disintegrin-like/cysteine-rich (D/C) family, was purified to homogeneity from the venom of Tunisian snake Macrovipera lebetina transmediterranea. It is a monomeric protein with a molecular mass of 25,787 Da. Its complete sequence of 205 amino acid residues was established by cDNA cloning. The leberagin-C shows many conserved sequences with other known D/C proteins, like the SECD binding sites and a pattern of 28 cysteines. It is the first purified protein from M. lebetina transmediterranea with only two disintegrin-like/cysteine-rich domains. Leberagin-C is able to inhibit platelet aggregation induced by thrombin and arachidonic acid with IC(50) of 40 and 50 nM respectively. It was also able to inhibit the adhesion of melanoma tumour cells on fibrinogen and fibronectin, by interfering with the function of alphavbeta3 and, to a lesser extent, with alphavbeta6 and alpha5beta1 integrins. To our knowledge, leberagin-C is the sole described D/C protein that does not specifically interact with the alpha2beta1 integrin. Structure-activity relationship study of leberagin-C suggested that there are some important amino acid differences with jararhagin, the most studied PIII metalloprotease from Bothrops jararaca, notably around the SECD motif in its disintegrin-like domain. Other regions implicated in leberagin-C specificities could not be excluded.