Synthesis of MCM-41 nanomaterial from Algerian bentonite: influence of synthesis pH

Mesoporous materials of the MCM-41 type were synthesized from Algerian bentonite as an aluminosilicate source without the addition of pure silica and aluminum reagents. The samples were synthesized under hydrothermal condition using cetyltrimithylammonium bromide (CTAB) as surfactant. The influence of initial synthesis pH on the material properties of as-synthesis MCM-41 samples was studied at different temperatures of crystallization. The samples were characterized using several techniques e.g. X-ray diffraction (XRD), N2 adsorption-desorption and transmission electron microscope (TEM). The experimental results showed that bentonite can be used as an aluminosilicate source for the synthesis of Al-MCM-41. By decreasing the synthesis temperature of crystallization, it is necessary to decrease the synthesis pH value to form the best ordered hexagonal phase and eliminate the lamellar phase.Keywords: bentonite; alkaline fusion; pH; Al-MCM-4

Isolation and identification of bacterial strain I33M producing milk-clotting enzyme: Optimization of culture parameters using response surface

A strain I33M which produces a milk-clotting enzyme was screened from Algerian soil near a dairy factory. This strain was identified as Bacillus mojavensis based on morphology and internal transcription spacer sequence. Sequencing analysis of 16S rDNA gene showed 100% identity of the tested strain with the B. mojavensis in the database. Phylogenetic analysis of this strain showed that it was most closely related to Bacillus subtilis strain. The optimum levels of these significant parameters to obtain the highest milk clotting activity and the lowest proteolytic activity were determined employing the response surface methodology (RSM), which revealed these as follows: wheat bran 7%, casein 0.094%, temperature 39°C, agitation size (rpm) 150. Among the various variables screened, agitation and temperature were most significant in submerged fermentation (SmF). The optimal value of milk clotting activity (MCA) is esteemed at 2.40. Key words: Milk clotting protease, Bacillus, response surface methodology, sequencing analysis

Empirical equations for the estimation of natural mortality in Mediterranean teleosts

Empirical relationships were established linking estimates of the instantaneous rate of natural mortality (M), the von Bertalanffy growth parameters, L sub( infinity ) (or W sub( infinity )) and K, and annual mean water temperature in 56 stocks of Mediterranean teleosts fish. It is suggested that these relationships generate for these fish more reliable estimates of M than the widely-used model of Pauly (1980, J. Cons. CIEM 33(3):175-192), which was based on 175 fish stocks, but included only five stocks from the Mediterranean

Planning & Acting: Optimal Markov Decision Scheduling of Aggregated Data in WSNs by Genetic Algorithm

Data aggregation techniques have emerged as promising solutions for extending Wireless Sensor Networks (WSNs) lifetime. However, this approach suffers from a design issue in delivering the strict requirements needed by some monitoring applications. Carefully balancing Energy, Delay and Accuracy is essential for achieving these requirements. In this work, we focus on distributed data aggregation, where a sensor estimates the network information by the exchange of readings with different priority levels. We then propose an optimal decision policy for scheduling the transmission of the aggregated data at the node level. To model the investigated problem, we first adopt Markov Decision Process (MDP) whereby we define the reward function. Then, we apply a Genetic Algorithm (GA) to find a set of optimal decisions that ensures the best trade-off between energy saving, delay and accuracy of the received data based on their priority level. The simulation results yield excellent performance and our optimization shows a significant enhancement up to 20% compared to the other policies

Empirical equations for the estimation of natural mortality in Mediterranean teleosts

Natural mortality, Statistical analysis, Mediterranean Region, Teleostei

Obstructive jaundice secondary to pancreatic head adenocarcinoma in a young teenage boy: a case report

<p>Abstract</p> <p>Introduction</p> <p>Pancreatic adenocarcinoma is extremely rare in childhood. We report a case of metastatic pancreatic adenocarcinoma in a 13-year-old boy, revealed by jaundice.</p> <p>Case presentation</p> <p>A 13-year-old Moroccan boy was admitted with obstructive jaundice to the children's Hospital of Rabat, Department of Pediatric Oncology. Laboratory study results showed a high level of total and conjugated bilirubin. Computerized tomography of the abdomen showed a dilatation of the intra-hepatic and extra-hepatic bile ducts with a tissular heterogeneous tumor of the head of the pancreas and five hepatic lesions. Biopsy of a liver lesion was performed, and a histopathological examination of the sample confirmed the diagnosis of metastatic ductal adenocarcinoma of the pancreas. Our patient underwent a palliative biliary derivation. After that, chemotherapy was administered (5-fluorouracil and epirubicin), however no significant response to treatment was noted and our patient died six months after diagnosis.</p> <p>Conclusion</p> <p>Malignant pancreatic tumors, especially ductal carcinomas, are exceedingly rare in the pediatric age group and their clinical features and treatment usually go unappreciated by most pediatric oncologists and surgeons.</p

Etude comparative des huiles essentielles de six variétés des nouvelles obtentions d’agrumes cultivées au Maroc

In this research, the essential oils of six INRA’s citrus varieties, which are mandarines El Marzaka, El Mahdia, El Gharabaouia, El Hamra, El Maamoura and orange Shemsia were compared and analyzed. For this purpose, the oil yield, chemical composition, antioxidant and antimicrobial activity were investigated. The extraction was carried out by hydro-distillation. The highest essential oil yield was obtained for Shemsia (5,63%/ DW). The main components of essential oils were identified by GC-MS and their antioxidant activity was determined by DPPH method. The major component of essential oils is D-Limonene, and the highest antioxidant activity was obtained for Shemsia essential oil (24.02%). Antifungal activity was detected in all varieties and the highest value was identified in El Maamoura, while antibacterial activity was not distinguished. From the obtained results, we note that the essential oils of El Maamoura can be valued as a fungicide in agriculture or in medical field. in addition, El Hamra, can be used in Solar cream industry.Les huiles essentielles de six variétés d’agrumes obtenues de l’INRA du Maroc, et qui sont : les mandarines El Marzaka, El Mahdia, El Gharabaouia, El Hamra, El Maamoura et l’orange Shemsia ont été comparées et analysées. La comparaison a été effectuée en termes de rendement, de composition chimique, d’activité antioxydante et d’activité antimicrobienne de ces huiles essentielles. L’extraction a été effectuée par hydro-distillation. Le rendement en huile essentielle le plus élevé a été obtenu chez la variété Shemsia (5,63%/PS). Les principaux composants des huiles essentielles ont été identifiés par CPG-MS et leur activité antioxydante a été déterminée en testant la capacité de piégeage des radicaux libres par DPPH. Le composant majeur des huiles essentielles est le D-Limonène et la plus haute activité antioxydante a été obtenue pour l'huile essentielle d’El Maamoura (24,02%). L'activité antifongique a été détectée chez toutes les variétés et la valeur la plus élevée a été repérée chez El Maamoura, alors que l'activité antibactérienne n'a été détectée chez aucune variété. À partir des résultats obtenus, nous constatons que l’huile essentielle de la mandarine El Maamoura peut être valorisée sous forme de fongicide dans le domaine d’agriculture ou dans le domaine médical. En plus, la variété El Hamra peut être incorporée dans l’industrie de la fabrication des crèmes solaires

Prise en charge du couple mère enfant de la varicelle pendant la grossesse

La varicelle est une maladie généralement bénigne chez l’enfant, cependant l’atteinte de l’adulte est potentiellement grave et son association à la grossesse expose la mère et le nouveau né à des risques de complications plus redoutables.La prise en charge multidisciplinaire associant obstétricien, biologiste et pédiatre est indispensable pour limiter les effets délétères de l’infection par la varicelle pendant la grossesse.Nous rapportons dans cet article les approches thérapeutiques actuellement proposées pour la prise en charge anté et péripartum du couple mère-enfant en cas d’infection par la varicelle pendant la grossesse et nous proposons des conduites visant à atténuer les complications maternelles

Shared Skeletal Support in a Coral-Hydroid Symbiosis

Hydroids form symbiotic relationships with a range of invertebrate hosts. Where they live with colonial invertebrates such as corals or bryozoans the hydroids may benefit from the physical support and protection of their host's hard exoskeleton, but how they interact with them is unknown. Electron microscopy was used to investigate the physical interactions between the colonial hydroid Zanclea margaritae and its reef-building coral host Acropora muricata. The hydroid tissues extend below the coral tissue surface sitting in direct contact with the host's skeleton. Although this arrangement provides the hydroid with protective support, it also presents problems of potential interference with the coral's growth processes and exposes the hydroid to overgrowth and smothering. Desmocytes located within the epidermal layer of the hydroid's perisarc-free hydrorhizae fasten it to the coral skeleton. The large apical surface area of the desmocyte and high bifurcation of the distal end within the mesoglea, as well as the clustering of desmocytes suggests that a very strong attachment between the hydroid and the coral skeleton. This is the first study to provide a detailed description of how symbiotic hydroids attach to their host's skeleton, utilising it for physical support. Results suggest that the loss of perisarc, a characteristic commonly associated with symbiosis, allows the hydroid to utilise desmocytes for attachment. The use of these anchoring structures provides a dynamic method of attachment, facilitating detachment from the coral skeleton during extension, thereby avoiding overgrowth and smothering enabling the hydroid to remain within the host colony for prolonged periods of time