Entrapment of Lentinus sajor-caju into Ca-alginate gel beads for removal of Cd(II) ions from aqueous solution: preparation and biosorption kinetics analysis

A white rot fungus species Lentinus sajor-caju biomass was entrapped into alginate gel via a liquid curing method in the presence of Ca(II) ions. The biosorption of cadmium(II) by the entrapped live and dead fungal biomass has been studied in a batch system. The heat-treatment process enhanced the biosorption capacity of the immobilized fungal biomass. The effect of initial cadmium concentration, pH and temperature on cadmium removal has been investigated. The maximum experimental biosorption capacities for entrapped live and dead fungal mycelia of L. sajur-caju were found to be 104.8±2.7 mg Cd(II) g⁻¹ and 123.5±4.3 mg Cd(II) g⁻¹, respectively. The kinetics of cadmium biosorption was fast, approximately 85% of biosorption taking place within 30 min. The biosorption equilibrium was well described by Langmuir and Freundlich adsorption isotherms. The change in the biosorption capacity with time is found to fit pseudo-second-order equations. Cadmium binding properties of entrapped fungal preparations have been determined applying the Ruzic equations. Since the biosorption capacities are relatively high for both entrapped live and dead forms, they could be considered as suitable biosorbents for the removal of cadmium in wastewater treatment systems. The biosorbents were reused in three consecutive adsorption/desorption cycles without significant loss in the biosorption capacity.     

Preconcentration and determination of lead, cadmium and nickel from water samples using a polyethylene glycol dye immobilized on poly(hydroxyethylmethacrylate) microspheres.

A simple and sensitive preconcentration analysis-atomic absorption spectrometric procedure is described for the determination of lead, cadmium and nickel. The method is based upon on-line preconcentration of metal ions on a minicolumn of Cibacron Blue F3-GA immobilized on poly(hydroxyethylmethacrylate), poly(HEMA). The enrichment factors obtained were 42 for lead, 52 for cadmium and 63 for nickel (sample volume 10 mL and sample flow rate 5 mL/min). The relative standard deviations (n = 10), in 10 mL sample solutions containing 100 microg/L Pb(2+), 10 microg/L Cd(2+) and 100 microg/L Ni(2+) were 8.9, 3.7 and 3.5%, respectively. The limits of detection (blank + 3s) (n = 10), were found to be 12.01 microg/L for Pb(2+), 1.34 microg/L for Cd(2+) and 28.73 microg/L for Ni(2+). The accuracy of the system was checked with certified and tap water samples spiked with known amounts of metal ions. No significant difference was found between the achieved results and the certified values.     

Structural Investigation of bis(4-methyl-1-piperazineglyoximato)dipyridinato cobalt(III) chloro dinitrate trihydrate

The crystal and molecular structure of the title compound,C24H36CoN10O(4).2(NO3).3(H2O).Cl, have been determined by X-ray analysis: Cc (No: 9), a = 17.6920(4) A, b = 11.8163(2) A, c = 16.4752(4) A, Beta = 91.679(1) degrees , Z = 4. The Co(III)ion is six-coordinated with octahedral geometry, the pyridine rings are planar and the piperazine rings assume chair conformations.     

Comparison of relative INAA and k0-INAA using proficiency test materials at ITU TRIGA Mark II research reactor

Journal of Radioanalytical and Nuclear Chemistry - Proficiency testing is an important way of evaluating the analytical method used in the laboratory. In recent years, neutron activation analysis...     

pH-labile sheddable block copolymers by RAFT polymerization: Synthesis and potential use as siRNA conjugates

Well-defined amphiphilic block copolymers composed of hydrophilic and hydrophobic blocks linked through an acid-labile acetal bond were synthesized directly by RAFT polymerization using a new poly(ethylene glycol) (PEG) macroRAFT agent modified with an acid-labile group at its R-terminal. The new macroRAFT agent was used for polymerization of poly(t-butyl methacrylate) (PtBMA) or poly(cholesterol-methacrylate) (PCMA) to synthesize well-defined block copolymers with a PEG block sheddable under acidic conditions. The chain extension polymerization kinetics showed known traits of RAFT polymerization. The molecular weight distributions of the copolymers prepared using the new macroRAFT agent remained below 1.2 during the polymerizations and the molecular weight of the copolymers was linearly proportional to monomer conversions. The acid-catalyzed hydrolysis behavior of the PEG-macroRAFT agent and the PEG-b-PtBMA (Mn = 13,600 by GPC, PDI = 1.10) was studied by GPC, ¹H NMR and UV–vis spectroscopy. The half-life of acid-hydrolysis was 70 min at pH 2.2 and 92 h at pH 4.0. The potential use of the pH-labile shedding behavior of the copolymers was demonstrated by conjugating a thiol-modified siRNA to ω-pyridyldisulfide modified PEG-b-PCMA. The resultant PEG-b-PCMA-b-siRNA triblock modular polymer released PCMA-b-siRNA segment in acidic and siRNA segment in reductive conditions, as confirmed by polyacrylamide gel electrophoresis.     

Peters type polynomials and numbers and their generating functions: Approach with p‐adic integral method

The aim of this paper is to introduce and investigate some of the primary generalizations and unifications of the Peters polynomials and numbers by means of convenient generating functions and p‐adic integrals method. Various fundamental properties of these polynomials and numbers involving some explicit series and integral representations in terms of the generalized Stirling numbers, generalized harmonic sums, and some well‐known special numbers and polynomials are presented. By using p‐adic integrals, we construct generating functions for Peters type polynomials and numbers (Apostol‐type Peters numbers and polynomials). By using these functions with their partial derivative eqautions and functional equations, we derive many properties, relations, explicit formulas, and identities including the Apostol‐Bernoulli polynomials, the Apostol‐Euler polynomials, the Boole polynomials, the Bernoulli polynomials, and numbers of the second kind, generalized harmonic sums. A brief revealing and historical information for the Peters type polynomials are given. Some of the formulas given in this article are given critiques and comments between previously well‐known formulas. Finally, two open problems for interpolation functions for Apostol‐type Peters numbers and polynomials are revealed.     

New copper(II) complexes including pyridine-2,5-dicarboxylic acid: synthesis,spectroscopic, thermal properties,crystal structure and how these complexes interact with purified PON 1 enzyme

We report the synthesis of two square-pyramidal copper(II) complexes, [Cu(2,5-pydc)(2-aepy)(H₂O)]·H₂O, 1, and [Cu(2,5-pydc)(2-ampy)(H₂O)]·H₂O, 2 (2-aepy = 2-(aminoethyl)pyridine, 2-ampy = 2-(aminomethyl)pyridine, 2,5-pydc = pyridine-2,5-dicarboxylic acid or isocinchomeronic acid). The synthesized complexes have been characterized by X-ray diffraction, FT-IR, elemental, and thermal analysis techniques. The crystal structure of 1 was established by X-ray analysis. Powder X-ray diffraction analysis showed that the complexes are pure. The inhibition of human serum paraoxonase 1 (PON 1, EC 3.1.8.1) enzyme with these complexes were investigated. We used diethyl 4-nitrophenyl phosphate as a substrate to measure the paraoxonase activity of PON 1 enzyme spectrophotometrically. Complexes 1 and 2 decreased the in vitro PON 1 activity with different inhibition mechanisms. Complexes 1 and 2 inhibited paraoxonase activity of this enzyme as competitively and noncompetitively, respectively.     

New metal complexes with diclofenac containing 2-pyridineethanol or 2-pyridinepropanol: synthesis,structural, spectroscopic,thermal properties,catechol oxidase and carbonic anhydrase activities

Four new neutral diclofenac-based complexes, [Co(dicl)2(2-pyet)2] 1, [Ni(dicl)2(2-pyet)2] 2, [Cu2(dicl)2(2-pyet)2] 3, and [Cu2(dicl)2(2-pypr)2] 4 have been synthesized and characterized by elemental analysis, FT-IR, thermal analysis. Complexes 1, 3, and 4 have also been characterized by X-ray single-crystal structural analysis. The compounds of Co(II) and Ni(II) have octahedral geometry with two diclofenac and two 2-pyridineethanol ligands in the coordination sphere. The compounds of Cu(II) have square-pyramidal geometry and Cu(II) ions are linked via oxygens to the bridging 2-pyridineethanol or 2-pyridinepropanol ligands. The Δν values acquired by FT-IR are in agreement with the single XRD data. Studies on the thermal properties are reported and the complexes are stable to 196, 216, 215, and 201 °C in air, respectively. Two dinuclear Cu(II) complexes have demonstrated catalytic activity on oxidation of 3,5-di-tert-butylcatechol to 3,5-di-tert-butylquinone showing saturation kinetics at high substrate concentrations. The diclofenac complexes are investigated as inhibitors of the human cytosolic isoforms hCA I and II. The complexes are good as hCA I inhibitors (Kis of 1.52–55.06 μM) but only moderately efficient as hCA II inhibitors (Kis of 0.23–5.61 μM).     

Thermodynamic stability and reactivity of silylated bis(oxy)iminium ions

Silylation of various nitronates with trialkylsilyl triflates was investigated by applying NMR techniques. In several cases, a flexible nitronate-bis(oxy)iminium ion (as an ion pair with triflate as counterion) equlibrium was found, and its thermodynamic parameters were determined. Elevation of temperature or dilution shifts this equilibrium toward the reactants. Activation parameters for the C,C-coupling reaction of silylated bis(oxy)iminium ions with a series of reference nucleophiles were determined. Estimated electrophilicity of bis(oxy)iminium ions allows one to count on C,C-coupling when partner nucleophilicity is N > 4.     

Computation methods for combinatorial sums and Euler‐type numbers related to new families of numbers

The aim of this article is to define some new families of the special numbers. These numbers provide some further motivation for computation of combinatorial sums involving binomial coefficients and the Euler kind numbers of negative order. We can show that these numbers are related to the well‐known numbers and polynomials such as the Stirling numbers of the second kind and the central factorial numbers, the array polynomials, the rook numbers and polynomials, the Bernstein basis functions and others. In order to derive our new identities and relations for these numbers, we use a technique including the generating functions and functional equations. Finally, we give not only a computational algorithm for these numbers but also some numerical values of these numbers and the Euler numbers of negative order with tables. We also give some combinatorial interpretations of our new numbers. Copyright © 2016 John Wiley & Sons, Ltd.