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Le bassin versant de l'Oued Tafna est forme´ par les reliefs et des zones de´prime´es, qui s'alternent du Nord au Sud et dont le volume augmente conside´rablement dans le meˆme sens. Le re´seau hydrographique a un trace´ ge´ne´ral orthogonal meˆme si la Tafna et ses principaux affluents de´crivent sinuosite´ et me´andre, sa densite´ et son abondance augmentent dans le meˆme sens que le volume des reliefs, c'est a` dire vers le Sud. Les apports les plus importants et les plus fluctuants pour la moyenne et la basse Tafna, sont observe´s pendant l'hiver et le printemps, pour le reste de l'anne´e, les apports sont faibles, ou le plus souvent sont alimente´s par les rejets d'eaux use´es urbaines et industrielles, comme c'est le cas pour l'Oued Mouilah, ou` les eaux use´es constituent l'essentiel du de´bit d'e´tiage. Le bassin hydrographique de la Tafna a une superficie de 7,250 km2 et alimente cinq barrages qui sont du plus ancien au plus re´cent Beni Bahdel (66 Hm3), Meffrouch (15 Hm3), Sidi Abdeli (110 Hm3), Hammam Boughrara (177 Hm3) et celui en cours de construction Sikkak (27 Hm3). Les donne´es montrent que les augmentations de la turbidite´ et du MES pendant les crues sont dues essentiellement aux teneurs en matie`res mine´rales grossie`res et que l'accroissement de la conductivite´ a` l'e´tiage est du a` une forte concentration en NaCl (jusqu'a` 14 g/l). Le re´seau hydrographique peut eˆtre se´pare´ en deux zones soumises a` des conditions diffe´rentes; la zone amont, stable, peu influence´e par les variations de de´bits et la zone avale, soumise a` l'alternance cruee´tiage, aux eaux tre`s charge´es en matie`res mine´rales hydrographique de la Tafna est caracte´rise´e par une eau tre`s mine´ralise´e puisqu'elle pre´sente une conductivite´ au niveau des sources de 600 μs/cm en moyenne lie´e a` la nature des terrains traverse´s. Cette mine´ralisation augmente de l'amont vers l'aval, ceci est lie´ en majeure partie aux chlorures. Une prise d'eau juste avant l'embouchure de la Tafna est effectue´e a` un de´bit de 11 340 m3/h. Cette eau brute est pre´traite´e par deux de´canteurs — floculateurs de 58 m de diame`tres chacun. L'eau pre´traite´e est pompe´e vers la station de traitement de Dzioua qui se trouve sur le bassin des coˆtiers oranais de l'Agence de Bassin Hydrographique Oranie-Chott-Chergui dont fait partie le Bassin Versant de la Tafna ou` l'eau est stocke´e dans un crate`re de volume de 13 000 000 m3. Cette eau est ae´re´e et traite´e par des filtres a` sables avec une production de 24 000 m3/j. Cette quantite´ d'eau alimente particulie`rement les couloirs des villes de Be´ni Saf, d'Ai¨n Temouchent et d'Oran; cette dernie`re grande ville ayant besoin d'une quantite´ de 320 000 m3/j. Les eaux du bassin hydrographique de la Tafna sont traite´es par ce proce´de´ physico-chimique dont il a e´limine´ presque entie`rement les matie`res en suspension et les matie`res organiques mais laisse passer les sels dissous de concentration de l'ordre de 1,5 g/l. [Copyright 2003 Elsevier]

The objective of this research is to manufacture new filter pellets based on polyacrylamide (PAM) activated carbon (GAC), iron oxide (Fe2O3), zinc oxide (ZnO) and kaolin and to evaluate their effectiveness in removing chromium and nickel from water. The synthesized filter pellets were characterized by FTIR, XRD and X-ray fluorescence. The XRF validation method would involve known amounts of chromium and nickel being retained by the filter pellets. the application of XRF gave precise measurements of the concentrations of Cr(VI) and Ni(II) fixed in the filter pellets. It was found that the values of the retention rates of Cr(VI) ions are higher in comparison with Ni(II) ions .The inclusion of inorganic additives influences the ability of filter pellets (FP) to retain Cr(VI) and Ni(II). FP2 (ZnO) showed reduced retention for both ions in comparison to FP1 (Fe2O3) and FP3 (Kaolin). FP3 (Kaolin) displayed better retention capacities for Cr(VI) and Ni(II) ions. The conductometric approach was also used to evaluate the retention of ions by the filter pellets. Comparing the conductivity of the feed solution with that of the filtered solution and the comparison between the different materials provided information on the most effective filter pellets for this purpose. [ABSTRACT FROM AUTHOR]

In a previous paper, we reported on the structural properties of a 35-residue peptide corresponding to a modified basic subdomain (bSD) of the basic zipper protein c-Jun (residues 252–281) as determined by combined use of 1H-NMR, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopies [Krebs, D., Dahmani, B., El Antri, S., Monnot, M., Convert, O., Mauffret, O., Troalen, F. & Fermandjian, S. (1995) Eur. J. Biochem. 231, 370–380]. The fragments NP and CP (the N-terminal residues 1–19 and C-terminal residues 16–35 of bSD, respectively) proved to be particularly useful for the assignment of the 1H-NMR spectra of the full-length bSD, which has been achieved completely in aqueous solution and partially in trifluoroethanol. Here, we report on the structural properties of NP and CP in aqueous solution and under varying H2O/trifluoroethanol conditions, again using 1H-NMR, CD and FT-IR experiments. Both CD and FT-IR results established that the fragments are weakly structured in aqueous solution. Addition of trifluoroethanol to aqueous solutions of the peptides produced their stabilization into helix, following a profile sigmoidal for NP and nearly linear for CP. Quantitative NOEs, secondary · Hα chemical shifts, NH temperature coefficients and 3JαN coupling constants for the peptides in aqueous solutions provided indications for weak helix features (nascent helices) manifested within two sites (continuous dNN NOEs) in both NP and CP. For each peptide, an excellent agreement was observed between experiments and predictions with the AGADIR program for the location of these nascent helices in the sequences. Trifluoroethanol provoked both the α-helix stabilization within these sites and the α-helix propagation to adjacent amino acid residues. Finally, our results reflected the high flexibility and helix potential of the NP and CP fragments, these two properties seeming crucial for the accomodation of c-Jun to its specific DNA targets. The results demonstrated also the fragmentation's benefits in dissecting a protein or a complex peptide into smaller fragments and analyzing their structure individually. [ABSTRACT FROM AUTHOR]

Examines the structural properties of the basic subdomain of the basic zipper (bZIP) oncoprotein c-Jun. Identification of the basic subdomain responsible for sequence-specific recognition of DNA; Modification of basic subdomain bSD; Reasons why the addition of trifluoroethanol to an aqueous bSD sample resulted in an increase of the alpha-helix spectra.

The crystal structure of poly (vinylidene fluoride) (PVDF) and morphology of composite membranes prepared from mixture of PVDF, Polyvinylpyrrolidone (PVP) and Sodium Maghnite nanoclay has been investigated in this research work. Several analytical methods were used for the characterisation of synthesised membrane samples such as FTIR spectroscopy, X-ray diffraction (XRD), porosity and contact angle It was found the effect of adding of increasing amounts of Maghnite can improve the piezoelectric phase of PVDF. These is confirmed by the increase of the Beta crystal phase ratio. It was proved also that the synthetised membranes occurs different interaction with Serum Albovine protein by the increase of the fouling index fluxes for the membrane with reach content of Maghnite. Which confirm that the deposition effect of BSA in the membrane surface with high amounts of ß crystal structures. [ABSTRACT FROM AUTHOR]

Matrix hybrid membranes, based on polyvinylidene fluoride (PVDF), poly (N-vinylpyrrolidone) (PVP), silica gel (SG) and zinc oxide (ZnO) were synthesized by phase inversion via immersion precipitation method. The characterization of membrane samples was performed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), optical microscopy, contact angle, porosity, mean pore size and water permeability measurements. The FTIR analysis showed the appearance of new bands attributed to the functional groups of SG and ZnO. The XRD analysis confirmed a modification in the structure of membranes. The prepared membranes were used for the removal of hexavalent chromium (Cr(VI)) from aqueous solution. Membrane filtration experiments show that the water permeability and Cr(VI) rejection ratios increase with increasing the weight ratio ZnO (%)/SG (%). The maximum values of the Cr(VI) rejection rate and water permeability were respectively 85% and 685 L/m2hbar for weight ratios (0.75% of ZnO/0.25% of SG). [ABSTRACT FROM AUTHOR]

Microalgae represent an important source of valuable bioproducts (such as food, nutraceuticals, antioxidants, and pigments) and biofuel. They grow spontaneously in surface water and represent a contaminant that has to be separated. There is thus an urgent need to develop technologies to harvest and refine them. Depending on the microalgae species, different biocompounds can be found and appropriate separation and purification methods must be refined and selected. In this work, microalgae harvested in the Hammam Boughrara dam, situated in Tlemcen (north‐west of Algeria), were used as source to recover and fractionate bio‐derived molecules using membrane‐assisted processes. This study identified a suitable strategy to fractionate biomolecules using ultrafiltration (UF) membranes. To maintain a stable permeate flux it was necessary to decrease the complexity of the solution prior to UF. This was achieved by separating triacylglycerols (TAGs) and pigments, after breaking cells, by solid–liquid–liquid extraction with a green solvent. The UF of the remaining aqueous phase permitted a recovery factor of 70% of the proteins and more than 85% of the carbohydrates in the retentate. The TAGs that were not recovered in the green solvent, and remained in the aqueous phase, were separated in the permeate with a purity of about 70% and a recovery factor of about 60%. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]