Classical and advanced chemical sciences
The Schiff base ligands 1-(2-furanyl) ethanone isonicotinoylhydrazone (L5H), 1-(2-thienyl)ethanone isonicotinoylhydrazone (L6H), 1-(2- pyridyl)ethanone isonicotinoylhydrazone (L7H), 1-(2-naphthyl)ethanone isonicotinoylhydrazone (L8H), were prepared by the condensation reaction of isonicotinic acid hydrazide with corresponding ethanons in 1:1 molar ratio, respectively, in ethanol under microwave exposure. The Mn (II) complexes have been prepared by mixing MnCl2.4H2O in 1:1 and 1:2 molar ratios with monofunctional bidentate ligands. The structure of the ligands and their transition metal complexes were confirmed by the elemental analysis, molecular weight determinations, IR, electronic and EPR spectral studies. On the basis of these studies it is clear that the ligands coordinated to the metal atom in a monobasic bidentate mode, by O∩N donor system. Thus a tetrahedral environment around the Mn(II) ion has been proposed. The antimicrobial activity of Schiff base ligands and their respective Mn(II) complexes were tested against some of pathogenic bacterial and fungal strains. The results indicated that the complexes showed higher activity than the parent ligands.
Keywords: Mn (II) complexes; Schiff base; Antimicrobial activity; microwave
Chemical and biological aspects of life
The River Nile is the essence of life in Egypt, but during the last decades its water quality has been changed by several factors, as a result of anthropogenic activities. The western branch of the River Nile is Rosetta Branch receives different types of pollution. The main origins of most pollutants are El-Rahawy drain and industrial activities in Kafr El-Zayat city. Water samples were analysed for physico-chemical parameters and blood samples for biochemical parameters of the Nile Tilapia; Oreochromis niloticus, to investigate the responses of fish towards these different types of pollution. Samples were collected from three sites from Rosetta branch of the River Nile during summer 2014 and winter 2015. S2 and S3 recorded an increase in water electrical conductivity (EC), total dissolved solids (TDS), biological oxygen demand (BOD) and chemical oxygen demand (COD), while dissolved oxygen (DO) and pH have been depleted. Nitrite, nitrates and ammonia levels also showed an elevation, especially in winter. Moreover, fundamental biochemical parameters such as; glucose, total protein, total lipid, albumin, cholesterol, triglycerides, kidney functions and liver functions in blood serum of O. niloticus recorded remarkable alterations, indicating stressful conditions, caused by the profound pollutants and poor water quality of water at these sites.
Keywords: River Nile, Rosetta branch, fish, biochemical parameters, physico-chemical parameters
Radioprotection by 2,3-dimethyl-6-(2-(dimethylamino)ethyl)-6H-indolo[2,3-b]quinoxaline (B220) on survival and growth of female C3H mice exposed to acute whole-body gamma-radiation was evaluated for 7.5-8 months following irradiation in two separate experiments. For adult (12 weeks old) mice, B220 administration increased median survival after 8 Gy by a factor of 1.27 when given within 24 h pre-irradiation, administration up to 24 h post-irradiation had a similar effect (1.20) but in addition resulted in 1 of 9 (11 %) mice alive after 32 weeks. For adult mice irradiated with 10-14 Gy, B220 had no significant effect on survival. For very young mice (4 weeks old), however, B220 administration within 24 h pre-irradiation protected from growth retardation at both 1 and 6 Gy, and from gray-hairing at 6 Gy. In conclusion, the well tolerated drug B220 offered radioprotection in both studies and its administration could be further optimized.
Keywords: development, lethal dose 50 % (LD50), 3,3'-diindolylmethane (DIM), reactive oxygen species (ROS), radical, radioprotector
The detection of extended spectrum β-lactamases (ESBL(S)) in Gram-negative bacteria that produce AmpC β-lactamases is problematic. In the present study, the performance of modified double-disc synergy test (MDDST) that employs a combination of cefepime and piperacillin-tazobactam for the detection of ESBL(S) Klebsiella producing AmpC β-lactamases was evaluated and compared with double-disc synergy test (DDST). E-test phenotypic confirmatory and modified three-dimensional tests (MTDT) were adopted for more data confidence. A total of 100 clinical isolates of Klebsiella, which met the CLSI (2012) screening criteria as having broth microdilution (BMD) MIC > or =2 mg mL-1 for at least one extended-spectrum cephalosporin [ceftazidime (CAZ), cefotaxime (CTX) and cefpodoxime], were accurately-selected for the study. MDDST detected ESBLs in 62 out of the100 studied isolates with 100 % sensitivity and specificity, whereas DDST detected ESBLs in only 52 isolates with 92.9 % sensitivity and 100 % specificity. E-test could detect ESBLs in 62 isolates, while as many as 34/62 ESBL positive isolates were confirmed to be AmpC beta-lactamase positive by the MTDT. MDDST and E-Test could detect ESBLs in all the 34 AmpC positive isolates, whereas DDST detects ESBLs in only 26 isolates. The study recommended MDDST as superior to DDST for the detection of ESBLs in AmpC β-lactamase-producing Klebsiella spp. and this was confirmed by MTDT and E-Tests.
Keywords: AmpC β-lactamase, extended-spectrum β-lactamases (ESBLs), Klebsiella spp., modified double-disc synergy test (MDDST), double-disc synergy test (DDST), phenotypic confirmatory test (E-test), modified three-dimensional test (MTDT)
Industrial and engineering chemistry, biotechnology
The electroreduction of manganese(II) chloride from chloride (NaCl-KCl) and fluoride-chloride (KCl-KF) melts has been studied in air atmosphere by polarography. In both melts, metallic manganese was obtained and the mechanism of the reduction of manganese(II)–ions was elucidated. Optimal parameters of the process could also be established
Keywords: electroreduction; manganese chloride; molten salts; voltammetry
The salts of Wadi El Natrun saline lakes are made up of sodium chloride (NaCl, halite), sodium sulfate (Na2SO4, thenardite) and sodium carbonate (Na2CO3.10H2O, natron) deposited on the bottom of the Lakes and surrounding sabkhas. The lakes of El Raizonia, Umm Risha, El Fasda, El Beida and El Gaar are the most potential lakes for economic halite salts. Furthermore, El Beida Lake contains Na2SO4 salts, mixed with halite, and Umm Risha and El Fasda lakes are characterized by natron salt showings. The chemical analysis of the saline water revealed dominant Cl-, Na+, Ca2+, CO32-, and HCO3- as major ions; while Mg2+, SO42- and NO3- are defined as minor ions. Chemical analysis of the salt deposits of these lakes shows similarity in the mineral composition with that of the saline water indicating that the water of such lakes is the main source of the realized salt minerals.
Keywords: Remote sensing, salt lakes, Wadi El Natrun.
Non-sedimentation nanoparticles containing alkaline wastewater as effluent from the cleaning process of car-painting lines can be purified by sedimentation after adding of mineral acids to adjust the pH below 5. Using 10 % aq. sulfuric acid to coagulate and filtrate the colloid particles, and adjusting the effluent pH with 10 wt. % aq. NaOH to the original value (~9), the wastewater can be recycled with ca. 0.3 % salt content into the cleaning process of the painting line (rinsing) technology.
Keywords: car-painting rinsing water; recycling; purification; coagulation