Pb(II)-phycoremediation mechanism using Scenedesmus obliquus: cells physicochemical properties and metabolomic profiling.

This study highlights the mechanisms of Pb(II)-phycoremediation using the Pb(II) tolerant strain of Scenedesmus obliquus. First, monitoring of cell growth kinetics in control and Pb(II)-doped medium revealed significant growth inhibition, while the analyses through flow cytometry and Zetasizer revealed no difference in cell viability and size. Residual weights of control and Pb(II)-loaded cells assessed by thermogravimetric analysis were 31.34% and 57.8%, respectively, indicating the uptake of Pb(II) into S. obliquus cells. Next, the use of chemical extraction to distinguish between the intracellular and extracellular uptake indicated the involvement of both biosorption (85.5%) and bioaccumulation (14.5%) mechanisms. Biosorption interaction of Pb(II) ions and the cell wall was confirmed using SEM-EDX, FTIR, zeta potential, zero-charge pH, and contact angle analyses. Besides, the biochemical characterization of control and Pb(II)-loaded cells revealed that the bioaccumulation of Pb(II) induces significant increases in the carotenoids and lipids content, while it decreases in the chlorophyll, carbohydrates, and proteins content. Finally, the metabolomic analysis indicated an increase in the relative abundance of fatty acid methyl esters, alkanes, aromatic compounds, and sterols. However, the alkenes and monounsaturated fatty acids decreased. Such metabolic adjustment may represent an adaptive strategy that prevents high Pb(II)-bioaccumulation in cellular compartments.

[Optimization of inventory levels in the blood transfusion centers in Morocco]. / Optimisation des niveaux de stock dans les centres de transfusion sanguine au Maroc.

PURPOSE OF THE STUDY: Improve the flow of quantities of blood products between the different centers to restore the ideal quantities at low cost. MATERIALS AND METHODS: The problem addressed in this work concerns the balancing inventory levels between blood transfusion centers in Morocco. This problem is characterized by a number of constraints to be taken into account: safety stock, stock ideal proportional balancing of stocks, etc. An integer linear model has been proposed to determine the optimal allocation between different centers. Two variants are examined; the first which aims to minimize the level of inventory loss, the second is to balance the different levels of stock, so that all centers have a level of surplus stock and/or loss proportional to the ideal stock. RESULTS: Two variants of an integer linear model that determine the optimal allocation between different centers has been proposed and their performance was evaluated by experimental results obtained using a solver commercial. CONCLUSION: The results of this study allow us to meet the goal of PSL availability of sufficient and subsequently the quality of service required blood transfusion.

[Improvement and process optimization transfusion in Morocco: proposal of a new organization]. / Amélioration et optimisation du processus transfusionnel au Maroc : proposition d'une nouvelle organisation.

PURPOSE OF THE STUDY: Propose a new organization for the Moroccan blood transfusion system. MATERIALS AND METHODS: Through an analysis of several aspects of the current organization, both qualitatively and quantitatively (Statistics 2011), it was found that several failures of the current system prevent them from achieving it's objectives and ensuring its responsibilities. Using multiple-criteria decision analysis (ELECTRE III), a new organization based on resources pooling is proposed. This new organization concerns the status of the National Blood Transfusion Center, donor management, the geographical location of the various regional centers, logistics, inventory management and the information system. RESULTS: Within the new organization proposed, the number of regional Centers for blood transfusion is reduced from 16 to 7 in accordance with the existing constraints, while redefining the roles of each site. The aspects of inventory management, the information system, increasing the number of donors, the policy communication and marketing and cycle of blood collection and distribution are also redefined. CONCLUSION: This proposed new organization will provide decision makers with the necessary assistance for decision making, whit respect to the improvement of the entire system Moroccan blood transfusion system. And so help achieving the desired objectives on ensuring blood availability and it' maximum safety. The simulation of this proposal should confirm the choice that was made. Further analysis of complementary aspects such as the financial aspect or human resources, would moreover contribute to refining this proposal.

[Evaluation of the response to vaccination against poliomyelitis and measles in malnourished children in Morocco]. / Evaluation de la réponse vaccinale contre la poliomyélite et la rougeole chez les enfants malnutris au Maroc.

We made a comparative survey of the poliovirus antibodies (anti-poliovirus type 1, anti-poliovirus type 2 and anti-poliovirus type 3) and the measles antibodies in malnourished but completely vaccinated children (37) and control children (34). The age range was 10 months to 5 years. Immunization in children with protein-energy malnutrition was low for both vaccines. Seroprevalence rates of the polio 1, polio 2, polio 3 antibodies and the measles antibodies in the control group were 94.1%, 97.1%, 91.2% and 82.4% respectively. In malnourished children the respective rates were in some cases significantly lower being: 40.5% (P = 0.001), 59.5% (P = 0.001), 40.5% and 35.1%. Malnutrition is a major determinant of the humoral response to oral polio and measles vaccines and must be given due consideration to prevent vaccination failure.