Processus d'eutrophisation : activité de la phosphatase alcaline du microplancton d'un réservoir mésotrophe marocain (Allal El Fassi)

L'activité de la phosphatase alcaline (APA) bactérienne et phytoplanctonique a été mesurée bimensuellement du mois de mars au mois de décembre 1998 au sein d'un réservoir mésotrophe situé dans une zone à climat semi-aride (Allal El Fassi, Maroc). Les résultats montrent que l'APA totale est importante (0,107-1,780 mmol PNP·l-1·h-1) et majoritairement d'origine bactérienne (> 60 %) au niveau de l'épilimnion, alors qu'elle est à dominance algale (> 58 %) dans le méta- et l'hypolimnion. L'absence de corrélation entre l'APA totale et les concentrations en orthophosphates suggère que l'hydrolyse par cette enzyme n'est pas significative dans le processus de régénération du phosphore dans ce réservoir. Par conséquent, l'APA ne pourrait pas être un indicateur fiable du déficit en phosphore dans le milieu.Bacterial and phytoplanktonic alkaline phosphatase activity (APA) was measured from march to December 1998 in the mesotrophic Allal El Fassi reservoir located in the semi-arid zone (Morocco). The total APA varied between 0.107-1.780 mmol PNP·L-1·h-1. In epilimnion, the bacterioplankton contributed significantly (> 60%) to total APA. In the meta and hypolimnion, the APA was predominantly algal (> 58%). No correlation between APA and orthophosphates indicate that the hydrolysis by this enzyme was not a significant process in recycling of phosphorus in Allal El Fassi reservoir. Consequently, the APA was not a valid test of phosphorus deficiency

Raman-active modes in defective peapod

International audienceThe vibrational properties of defective single-walled carbon nanotube filled with C60 fullerene is the subject of the current study. For this aim we use the spectral moments method in the framework of the bond-polarization theory to calculate the nonresonant Raman spectra of hexa-vacancy defective C60 peapods. Essentially, the vibrational properties are closely coupled with the atomic structure of the system. The evolution of the Raman spectrum as a function of the spatial arrangement of defects in carbon nanotubes is discussed. This work provides benchmark theoretical results to understand the experimental data of defective C60 peapod

A new T-S fuzzy model predictive control for nonlinear processes

Abstract: In this paper, a novel fuzzy Generalized Predictive Control (GPC) is proposed for discrete-time nonlinear systems via Takagi-Sugeno system based Kernel Ridge Regression (TS-KRR). The TS-KRR strategy approximates the unknown nonlinear systems by learning the Takagi-Sugeno (TS) fuzzy parameters from the input-output data. Two main steps are required to construct the TS-KRR: the first step is to use a clustering algorithm such as the clustering based Particle Swarm Optimization (PSO) algorithm that separates the input data into clusters and obtains the antecedent TS fuzzy model parameters. In the second step, the consequent TS fuzzy parameters are obtained using a Kernel ridge regression algorithm. Furthermore, the TS based predictive control is created by integrating the TS-KRR into the Generalized Predictive Controller. Next, an adaptive, online, version of TS-KRR is proposed and integrated with the GPC controller resulting an efficient adaptive fuzzy generalized predictive control methodology that can deal with most of the industrial plants and has the ability to deal with disturbances and variations of the model parameters. In the adaptive TS-KRR algorithm, the antecedent parameters are initialized with a simple K-means algorithm and updated using a simple gradient algorithm. Then, the consequent parameters are obtained using the sliding-window Kernel Recursive Least squares (KRLS) algorithm. Finally, two nonlinear systems: A surge tank and Continuous Stirred Tank Reactor (CSTR) systems were used to investigate the performance of the new adaptive TS-KRR GPC controller. Furthermore, the results obtained by the adaptive TS-KRR GPC controller were compared with two other controllers. The numerical results demonstrate the reliability of the proposed adaptive TS-KRR GPC method for discrete-time nonlinear systems

Fuzzy fractional hybrid differential equations

This article is related to present and solve the theory of fractional hybrid differential equations with fuzzy initial values involving the fuzzy Riemann-Liouville fractional differential operators of order $0 < q < 1$. For the concerned presentation, we study the existence and uniqueness of a fuzzy solution are brought in detail basing on the concept of generalized division of fuzzy numbers. We have developed and investigated a fuzzy solution of a fuzzy fractional hybrid differential equation. At the end we have given an example is provided to illustrate the theory

La gestion de l’eau d’irrigation par application de la théorie des jeux : cas de la région d’AL Haouz

In Morocco, water resources are limited and in most cases exposed to over-exploitation and degradation by actors with their non-rational behavior seeking to maximize their own profits until the resource is depleted. This competition to access a limited resource will provoke a conflict of interest between the different actors using this resource. This work was carried out in the El Haouz area with the objective of proposing the most relevant strategy for a good management of irrigation water resource. The game theory has been applied to the case study based on the prisoner's dilemma, as this methodology is typical of conflicts of interest around the use of natural resources. This methodology has contributed to identify the problems and suggest solutions adapted to the case study. Despite the difficulties encountered in bringing together the behaviors of the various actors, contracting policy appears to be a good alternative to achieve the objective of an integrated management of irrigation water while associating social welfare, economic and environmental well-being.Au Maroc, les ressources en eau sont limitées et sont dans la plupart des cas exposées à la surexploitation et à la dégradation par des individus avec leurs comportements non rationnel cherchant à maximiser leurs profits jusqu’à l’épuisement de la ressource. Cette situation de compétition pour l’accès à une ressource limitée va provoquer un conflit d’intérêt entre les différents individus usagers de cette ressource. Ce travail a été réalisé dans la zone d’El Haouz et dont l’objectif est d’identifier la meilleure stratégie de gestion de l’eau d’irrigation. La théorie de jeux a été appliquée au cas d’étude en se basant sur le dilemme du prisonnier vue que cette méthodologie est le cas typique des conflits d’intérêt autours de l’usage des ressources naturelles. Cette méthodologie a permis d’identifier les problèmes et proposer des solutions adaptées au cas d’étude. Il ressort que, malgré les difficultés rencontrées pour rapprocher les comportements des différents acteurs, la contractualisation semble être une bonne alternative pour atteindre l’objectif d’une gestion intégrée des eaux d’irrigation (Optimum de Pareto) tout en associant le bien-être social, économique et environnemental

Presoaking ACL grafts in vancomycin decreases the frequency of postoperative septic arthritis. A cohort study of 29,659 patients, systematic review, and meta-analysis from the SANTI Study Group

Background: Presoaking anterior cruciate ligament (ACL) grafts in vancomycin has been reported to reduce the occurrence of septic arthritis (SA). However, strong recommendations for its universal use have been precluded by concerns regarding the fragility of previous meta-analyses. Purpose: The primary objective was to investigate whether presoaking ACL grafts in vancomycin was associated with a reduction in the rate of SA in a large series of patients. The secondary objective was to perform an updated systematic review and meta- analysis to determine the efficacy of vancomycin in reducing the rate of SA. Study Design: Cohort study and systematic review; Level of evidence, 3. Methods: A retrospective analysis of patients who underwent primary ACL reconstruction (ACLR) at our institution was undertaken. Rates of postoperative SA were determined and analyzed according to whether patients had received grafts presoaked in vanco- mycin. A systematic review of the literature and meta-analysis was performed. Odds ratios (ORs) for the risk of SA were calculated according to the inverse variance approach. Results were presented using forest plots, funnel plots, and the fragility index. Results: A total of 5300 patients underwent primary ACLR during the study period. The rate of SA was 0.34% (11/3228) in the control group and 0.05% (1/2072) in the presoaked group. There was a 5-fold greater risk of SA in patients who did not receive grafts presoaked in vancomycin (OR, 5.13 [95% CI, 1.16-48.30]; P 1⁄4 .04). Overall, 11 studies were included in the systematic review (29,659 ACLR procedures). The meta-analysis demonstrated a significantly greater risk of SA in those patients who did not receive grafts presoaked in vancomycin (OR, 14.39 [95% CI, 5.90-35.10]; fragility index 1⁄4 23). This finding held true for the subpopulation receiving hamstring tendon grafts (fragility index 1⁄4 16), but only a trend was demonstrated for bone–patellar ten- don–bone grafts. Conclusion: The meta-analysis demonstrated that presoaking ACL grafts in vancomycin was associated with significant reductions in the rates of SA when all graft types were analyzed together. This finding held true specifically for hamstring tendon autografts. The fragility index of these findings allows for a strong recommendation for the universal use of vancomycin presoaking. However, it should be noted that only a trend toward reduced SA rates was demonstrated with presoaking bone–patellar tendon– bone autografts in vancomycin

Influence de la teneur de nickel sur le comportement tribologique et électrochimique de l’alliage TiNi.

Parmi les matériaux métalliques, les alliages de TiNi sont employés principalement pour des applications biomédicales et/ou dentaires dues à leur meilleure compatibilité mécanique avec les tissus, leur module de Young proche de celui de l’os et une résistance élevée à la corrosion dans les fluides du corps et une bonne biocompatibilité. Pour cette raison, le comportement à la corrosion et à l’usure de l’alliage TiNi avec des teneurs en Ni varie de 40 à 60% en poids, ont été étudiés afin de vérifier l’effet du Ni sur la biocompatibilité de cet alliage pour des applications dentaires

Primary tumor-induced immunity eradicates disseminated tumor cells in syngeneic mouse model

WOS: 000462721900029PubMed ID: 30926774Although clinically apparent metastasis is associated with late stages of cancer development, micro-metastatic dissemination may be an early event. However, the fate of these early disseminated tumor cells (DTC) remains elusive. We show that despite their capacity to disseminate into secondary organs, 4T1 tumor models develop overt metastasis while EMT6-tumor bearing mice clear DTCs shed from primary tumors as well as those introduced by intravenous (IV) injection. Following the surgical resection of primary EMT6 tumors, mice do not develop detectable metastasis and reject IV-injected tumor cells. In contrast, these cells readily grow and metastasize in immuno-deficient athymic or Rag2(-/- )mice, an effect mimicked by CD8(+) T-cell depletion in immunocompetent mice. Furthermore, recombinant G-CSF or adoptive transfer of granulocytic-MDSCs isolated from 4T1 tumor-bearing mice, induce metastasis by suppressing CD8(+) T-cells in EMT6-primed mice. Our studies support the concept of immune surveillance providing molecular insights into the immune mechanisms during tumor progression.Georgia Cancer Center; Forbes Institute research fund; Bridge Fund by Augusta University Research Inc.; American Cancer Society Institutional fundWe gratefully acknowledge the generous help from Flow Cytometry, Genomics Core facilities, and Labaratory of Animal Services. We thank Drs. Rafi Ahmed and Paulo C. Rodriguez for insightful discussions and comments, Dr. Iskander Asm for for helping with and training of our staff on the tail vein injections. This work was supported by start up funds to H.K. by Georgia Cancer Center. Additional research fundings to H.K. provided by American Cancer Society Institutional fund, Forbes Institute research fund, and Bridge Fund by Augusta University Research Inc

Quantitative atomic force microscopy provides new insight into matrix vesicle mineralization

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