Controlled synthesis of ZnO nanoparticles from a Zn(II) coordination polymer: Structural characterization,optical properties and photocatalytic activity

A zinc coordination polymer derived from pyridine-2,6-dicarboxylate (PDC), {[Zn₂(PDC)₂]}_n, was successfully prepared via conventional, sonication and microwave-irradiation methods. The composition and characteristics of the obtained coordination polymers (CPs) were investigated by elemental analysis, TGA/DTA, X-ray diffraction and spectroscopic techniques. The so obtained CPs were heat-treated in the air at 600 °C for 2 h to produce ZnO of nanosized particles (NPs). It is of interest to note that the synthesis approach of the precursor greatly affects both the nanoparticle size and the structure of the resulting ZnO NPs. Moreover, the smallest particle size was associated with the sample derived from the ultrasonically prepared precursor. TEM analysis revealed that all samples have sphere-like morphologies. Structural analysis of the prepared ZnO samples was conducted and compared using Rietveld analysis of their PXRD patterns. Optical band gap calculations based on analysis of the UV–vis spectra of ZnO samples using Tauc's power law were achieved. The highest band gap of 3.63 eV was observed for ZnO sample obtained from the ultrasonically prepared precursor. Furthermore, the photocatalytic activity of ZnO NPs for the removal of Eosin Y color was monitored. The highest removal efficiency was recorded for ZnO originated from the ultrasonically synthesized precursor. Enhancement of removal efficiency that reached 98% was attained in only a period of 8 min. Its recycling test showed that it can be reused without structural changes over four cycling experiments.     

Global Analysis of the Flows of Fluids with Pressure-Dependent Viscosities

 To describe the flows of fluids over a wide range of pressures, it is necessary to take into account the fact that the viscosity of the fluid depends on the pressure. That the viscosity depends on the pressure has been verified by numerous careful experiments. While the existence of solutions local-in-time to the equations governing the flows of such fluids are available for small, special data and rather unrealistic dependence of the viscosity on the pressure, no global existence results are in place. Our interest here is to establish the existence of weak solutions for spatially periodic three-dimensional flows that are global in time, for a large class of physically meaningful viscosity-pressure relationships. (Accepted May 1, 2002) Published online November 15, 2002 Communicated by S. S. ANTMAN     

Accumulation of uranium by filamentous green algae under natural environmental conditions

The capacity of algae to concentrate uranium under natural environmental conditions is measured by a-spectrometry. Spirogyra, a filamentous green fresh-water alga, has concentrated uranium from a surface concrete ponds with elevated uranium levels (140-1140 ppb). The concentration factors (CFs) ranged from 8.9-67 with an average value of 22.Cladophora spp, a filamentous green marine alga has concentrated uranium from the marine water with a concentration factor ranged from 220–280. The average concentration factor was 250. The factors affecting the sorption process are discussed in detail. This revised version was published online in July 2006 with corrections to the Cover Date.     

The physical interpretation of a painlevé transcendent spacetime

We construct a nondiagonalizable solution of the stationary axially symmetric vacuum Einstein equations involving Painlevé transcendents III(V). From the asymptotic behaviour of this solution we identify the corresponding Newtonian potential as that of a modulated line mass at=0, and we identify our transcendental solution as corresponding to a very special differentially rotating modulated line source.     

Separation of strontium from simulated waste in K2SO4/Nitrate medium containing Sr2+, Eu3+, Ce3+, Pd2+, Rh3+, Ru3+, UO 2 2+ , Fe3+, Cr3+, Ni2+, Al3+, Ca2+ and Cs+, by strongly basic anion exchanger

In this work Strontium was separated selectively form, Pd²⁺, Ni²⁺ and Ca³⁺ using anionic resins of Amberlite type IRA-900 and IRA-410 from nitrate medium. The Separation of strontium by strongly basic anion exchangers IRA-410 and IRA-900 from simulated waste containing, Sr²⁺, Eu³⁺, Ce³⁺, Pd²⁺, Rh³⁺, Ru³⁺, VO₂ ²⁺, Fe³⁺, Cr³⁺, Ni²⁺, Al³⁺, Ca²⁺, and Cs⁺, in K₂SO₄/nitrate medium which adsorbed as strontium sulphate complex was achieved through ligand- ligan exchange. The elution of strontium carried out via “loading” the column with a solution of 0.03N EDTA in presence of 0.1N NaNO₃ at pH7 where Sr²⁺ has low K_d value. An inductively Coubled Plasma — Optical Emission Spectrometry (ICP — OES) of ARL type model 3520, was used for elemental analysis.     

Complexes of tris(o-phenanthroline)nickel(II) and copper(II) bromide with dithiocarbamates derived from α-amino acids

Complexes of 1,10-o-phenanthroline (o-phen)-Ni^II and Cu^II with dithiocarbamates derived from -amino acids (glycine, phenylalanine, alanine, methionine and tryptophan) were synthesized and characterized by chemical analysis, spectral and thermal studies and by biological screening; the complexes are non-electrolytes. The empirical formula are [Ni(o-phen)₂(aadtc)] and [Cu₂(o-phen)₂(phaladtc)(H₂O)₂Br₂] where, aadtc = glycinyl-, phenylalaninyl-, alaninyl-, methioninyl- and tryptophanyldithiocarbamate and phaladtc = phenylalaninyldithiocarbamate. The structure of these complexes is probably octahedral. Molecular association through hydrogen bonding between the —NH and the carboxylate groups is proposed for the Ni^II complexes. The Cu^II complex is dimeric with the phenylalaninyldithiocarbamate acting as a bridge.     

Perfluoroalkylated eight- and nine-membered benzoheterocycles from F-2-methyl-2-pentene

The reactions of $\text{F}$-2-methyl-2-pentene (1) with several $\text{ortho}$- difunctional benzenes afforded eight- and nine-membered benzoheterocyclic compounds carrying perfluoroalkyl groups. Salicylic acid, salicylaldehyde, and their methyl or chloro derivatives reacted in triethylamine-acetonitrile system giving perfluoroalkylated 2H,6H-1,5-benzodioxocin-2,6-dione (8) and 4H,6H-1,5-benzodioxocin (9) compounds respectively, while phthalyl alcohol and o-hydroxyphenethyl alcohol in triethylamine-diethyl ether system gave perfluoroalkylated 1H,3H,7H-2,6- and 4H,6H,7H-1,5-benzodioxonin compounds, (10) and (11). o-Aminobenzyl alcohol and (1) in diethyl ether afforded a perfluoroalkylated benzoxazocinobenzoxazocinone compound (15).     

Synthesis and photochemistry of binary and mixed ligand complexes of copper(II) containing 5-arylazo-8-hydroxyquinoline derivatives and alkyl xanthates

Summary Mixed ligand complexes of the type K[Cu(x-HQA)Rxan] [x-HQA = 5-arylazo-8-hydroxyquinoline derivatives; Rxan = methyl or ethylxanthate] have been prepared and characterised by elemental analysis, spectral measurements and conductivity. Upon irradiation, solutions of these complexes photoeliminate dinitrogen and a mechanism for this reaction is proposed. The photosensitivity of the oxine ligand was found to be responsible for the observed photolysis of the complexes.     

Musa sp. Leaves Extract Ameliorates the Hepato-Renal Toxicities Induced by Cadmium in Mice

Heavy metals intoxication causes several health problems that necessitate finding new protective and therapeutic approaches. This study aimed to evaluate the impact of Musa sp. leaves extract (MLE) on hepato-renal toxicities induced by cadmium (Cd) in male mice. The phytochemical screening, metal chelating activity (MCA), and the median lethal dose (LD₅₀) of MLE were determined. Fifty CD-1 male mice were used and intraperitoneally (i.p.) injected with MLE (1000 to 5000 mg/kg b.wt) for MLE LD₅₀ determination. Another 50 mice were used for evaluating the effect of MLE on Cd toxicity. Blood samples were collected for hematological, liver, and kidney functions assessments. Liver tissue homogenates were used for determination of oxidant/antioxidant parameters. Liver and kidney tissues were harvested for histopathological and molecular investigations. MLE showed potent in vitro antioxidant activities. The MCA and LD₅₀ of the MLE were 75 µg/mL and 3000 mg/kg b.wt, respectively. MLE showed beneficial therapeutic activity against hepato-renal toxicities in Cd-intoxicated mice, evidenced by improving the hematological, biochemical, histopathological, and molecular alterations.