Volume 16, No. 3 (2015)
Articles
EVALUATION OF THE QUALITY OF DRINKING WATER PRODUCED BY THE TREATMENT PLANT: CASE OF MAURITANIA
MOHAMEDEN TFEILA(1), KHADIJA ZAHIDI(1), MOHAMED OULD SID’AHMED OULD KANKOU(2), SALAH SOUABI(1*), MOULAY ABDELAZIZ ABOULHASSAN(3)
This study aims to evaluate the performance of treatment plants after three years of operation of the city of Nouakchott. It essentially aims to study the evolution of various raw water qualities during the different processing steps (T °, pH, EC, MES, Cl-, NO3-, NO2-, sulfate...). The water treatment in Béni Nadji pretreatment station has led to a significant removal of turbidity, organic matter, and a 99-100 % elimination of SS (Suspended Solids). For drinking water, the total hardness varies between 3.8 and 5.6 °fH. The value of turbidity in drinking water was between 0.2 and 0.3 NTU with turbidity varying between 21 and 330 NTU in the surface water. Aluminum surface concentration surface was between 0.1 and 0.7 mg·L-1. The nitrate concentration varies between 0.5 and 2 mg·L-1, which is lower than that suggested by The World Health Organization (50 mg·L-1). As a result of this study, we concluded that water clarification phases of Nouakchott must be improved.
RADICAL QUENCHING OF METHANE-AIR PREMIXED FLAME IN MICROREACTORS USING DETAILED CHEMICAL KINETICS
JUNJIE CHEN(*), DEGUANG XU
The steady hetero-/homogeneous combustion of lean methane-air mixtures in plane channel-flow microreactors was investigated numerically to elucidate the effects of wall material and initial sticking coefficient on radical quenching. Simulations were performed with a two-dimensional numerical model employing detailed reaction mechanisms to examine the interaction between heterogeneous and homogeneous reactions on platinum, alumina, quartz and copper. Comparisons among wall materials revealed that the wall chemical effect plays a vital role in the distribution of OH* radical. Homogeneous reaction of methane over platinum is significantly inhibited due to the rapid depletion of reactants on catalytic surfaces, rather than the radical adsorption. The inhibition of radical quenching on the surface of alumina is most pronounced. As the microreactor is smaller than the critical dimension of 0.7 mm, the wall chemical effect on flame characteristics becomes of great importance.
NEW OXALATO AND BENZOATO ADDUCTS CONTAINING A SnR3 or SnR2 RESIDUE (R=Me, Bu, Ph): SYNTHESIS, INFRARED AND MOSSBAUER STUDIES
YAYA SOW, LIBASSE DIOP(*)
On allowing (i-Bu2NH2)2C2O4, (Cy2NH2)2C2O4.2H2O, (Pr2NH2)2C2O4, Pr2NH2HC2O4, (Me4N)2C2O4.2H2O or Cy2NH2O2CPh to react with SnPh3Cl, SnBu3Cl or SnMe3Cl, the seven studied adducts were obtained and studied by infrared and Mössbauer techniques. The suggested structures are discrete, the oxalate behaving as a non coordinating entity, only involved in hydrogen bonding while the benzoate is a mono-, bichelating or a monocoordinating ligand, the environments around the tin centres being trans or cis trigonal bipyramidal. When extra hydrogen bonds are considered involving free OH groups, a supramolecular architecture may be obtained. The key role of both the cation and the water molecules in the structures is noteworthy.
DEVELOPMENT OF SPECTROPHOTOMETRICAL ASSAY FOR THE STUDY OF THE INTERACTION OF ANTIOXIDANT STANDARDS WITH 1,1-DIPHENYL-2-PICRYLHYDRAZYL FREE RADICALS
TOUHAMI LANEZ(*), HADIA HEMMAMI
The aim of the present study was to develop a spectrophotometric based assay for the determination of binding parameters like binding constant and binding free energy of the free and 1,1-diphenyl-2-picrylhydrazyl (DPPH) bound forms of a set of antioxidant standards (AS). The determination of binding constant and binding free energy is based upon the decrease in absorbance of the electronic absorption spectrum of a 10-4 M acetonitrile solution of DPPH in the presence of a given concentration of a solution of antioxidant standards in the same solvent.
STIRRED BIOREACTOR FOR THE ROBUSTNESS PRODUCTION OF RECOMBINANT GST.VP28 IN FED-BATCH CULTIVATION OF ESCHERICHIA COLI
MUHAMAD ALI(1*), ISMAINI(1), SULAIMAN N. DEPAMEDE(1), BAGUS D.H. SETYONO(2), ALIS MUKHLIS(2), MUHAMAD AMIN(3), MOHAMMAD ASHARI(1)
Escherichia coli is the most popular platform for the production of recombinant proteins as vaccine candidates. One important factor that may influence the quantity and quality of the expressed proteins using the bacterial host is a bioreactor. Thus, this study was aimed at comparing the influence of two different bioreactors, conventional (Sakaguchi flask) and stirred bioreactors on the growth of E. coli BL21 as a host cell and production of GST.VP28 recombinant protein in the host. The result showed that total wet biomass of E. coli BL21 harvested from the stirred bioreactor was significantly higher, compared to the total biomass from the conventional bioreactors. In addition, SDS-PAGE results also indicated that the amount of the GST.VP28 recombinant protein collected from the stirred bioreactor was higher than the quantity of recombinant protein from E. coli cultured in the conventional bioreactor. Furthermore, the stirred bioreactor also produced larger soluble fraction and lower inclusion body. This result suggested that the stirred bioreactor is very suitable for improving the production of recombinant protein using E. coli.
SYNTHESIS, CHARACTERIZATION AND ANTITUMOR ACTIVITY OF A Ca (II) COORDINATION POLYMER BASED ON 3-AMINO-2-PYRAZINECARBOXYLIC ACID
XI-SHI TAI(1*), XIN WANG(2)
A new Ca(II) coordination polymer has been obtained by reaction of Ca(ClO4)2·H2O with 3-amino-2-pyrazinecarboxylic acid in CH3CH2OH/H2O. It was characterized by IR, 1HNMR, thermal analysis and X-ray single crystal diffraction analysis. X-ray analysis reveals that each Ca(II) center is seven-coordination with a N2O5 distorted pentagonal bipyramidal coordination environment. The Ca(II) ions are linked through the O atoms of 3-amino-2-pyrazinecarboxylic acid ligands to form 1D chain structure. And then a 3D network structure is constructed by hydrogen bonds and π-π stacking. The antitumor activity of 3-amino-2-pyrazinecarboxylic acid ligand and its Ca(II) coordination polymer against human intestinal adenocarcinoma HCT-8 cells, lung adenocarcinoma HCT-116 cells and human lung adenocarcinoma A549 cells line have been investigated.
STUDY ON SYNTHESIS AND CRYSTAL STRUCTURE OF TETRAKIS-(μ2-ACETATO)-DIHYDRATE-DICOPPER(II)
LI-HUA WANG(*)
A new binuclear Cu(II) complex, tetrakis-(μ2-acetato)-dihydrate-dicopper (II), has been prepared by the reaction of Cu(OAc)2·H2O with 2-formyl-benzenesulfonate-hydrazine in the CH3CH2OH/H2O (v : v = 1 : 1). It was characterized by elemental analysis, IR and X-ray single crystal diffraction analysis. The crystal of the Cu(II) complex belongs to monoclinic, space group C2/c with a = 13.162(3) Å, b = 8.5572(17) Å, c = 13.860(3) Å, β = 117.06(3) º, V = 1390.1(5) Å3, Z = 4, Dc = 1.889 μg·m-3, μ = 3.103 mm-1, F(000) = 792, and final R1 = 0.0548, wR2 = 0.1410. Two Cu(II) centers are bridged by oxygen atoms of carboxylato groups. Each Cu(II) center is five-coordinated with four O donor atoms of acetate and a O donor of coordinated water molecule. The molecules form three dimensional network structures by the inaction of π-π stacking and hydrogen bonds.
CONTRIBUTION TO DETERMINING THE BIOCHEMICAL COMPOSITION OF THE WATER CHESTNUT TRAPA NATANS L. LAKE OUBEIRA EL-KALA AND DEVELOPMENT OF NUTRIENT AGAR
MOHAMED SAHLI(1*), AISSA BOUTEBBA(2), ALI TAHAR(1)
This work is aims to determining the biochemical composition of the flour water chestnut seeds and the development of a nutrient agar for bacteria and fungi in the presence and absence of oxytetracycline. The culture medium consists of the filtrate recovered after dispersion of the flour of the seeds in distilled water and the agar. The results show in the absence of oxytetracycline, bacterial and fungal strains develop. In the presence of the antibiotic to 0.25 mg·mL-1 and 0.5 mg·mL-1 bacteria are completely inhibited whereas fungi evolve. Statistical analysis reveals the existence of a very highly significant difference (P ≤ 0.001) between the effects of different concentrations of the bactericide deploying Pyrenophora tritici and Septoria nodorum. There is no influence of antibacterial concentrations on the growth of Fusarium sp.
NEW TIN (IV), MX2 AND M’Cl3 (M= Zn, Hg; M’= Pr, Er) ADDUCTS AND COMPLEXES OF BIS(AMINOMETHYLBENZENE): SYNTHESIS AND INFRARED STUDY
ASSANE TOURE, LIBASSE DIOP(*)
The new adducts and complexes obtained have discrete or dimeric structures; in these structures the diamine behaves as a monodentate and hydrogen bonds involved or bidentate ligand. In one rare earth halide adduct the high coordination number (7) proposed is common for this family. When extra intermolecular hydrogen bonds are taken into account, supramolecular architectures may be obtained.
Zn2(Y)·H2O, (Me4N)2H2Y·3ZnCl2, (Me4N)4Y·5ZnCl2·H2O, (BzNMe3)2H2Y·2ZnBr2, Zn(H2Y)·4ZnCl2·2EtOH·14H2O AND Zn(H2Y)·6ZnCl2·2EtOH·6H2O (Y = EDTA): SYNTHESIS AND INFRARED STUDY
SERIGNE CISSE, IBRAHIMA CISSE, LIBASSE DIOP(*)
Six acidic or neutral ethylenediaminetetraacetato [H2Y2-, H3Y- or Y4-] containing adducts and derivatives have been synthesized and studied by infrared. The suggested structures are discrete with octahedral or tetrahedral environments around the zinc centres, the ethylenediaminetetraacetic anion behaving as a bichelating, trichelating, tetrachelating and hydrogen bonds involved, pentachelating or hexachelating and hydrogen bonds involved ligand. For most of the structures when intermolecular hydrogen bonds are considered, a supramolecular architecture is obtained.