A mixed‐ligand quinazoline‐based Ni(II) Schiff base complex: Synthesis,characterization, crystal structure,antimicrobial investigation and catalytic activity for the synthesis of 2H–indazolo[2,1‐b]phthalazine‐triones

A tridentate Schiff base ligand, (E)‐3‐((2‐hydroxy‐3‐methoxybenzylidene)amino)‐2‐methylquinazolin‐4(3H)‐one [HL], and its mixed‐ligand Ni(II) complex [Ni(L)(imi)], were synthesized and fully characterized using elemental analysis, FT‐IR, UV–Vis and ¹HNMR spectroscopy techniques. The structure of the synthesized ligand and complex was determined with single crystal X‐ray diffraction method. In the complex, a square planner geometry was observed around the Ni(II) central atom coordinated with the donor atoms of the Schiff base ligand and one nitrogen of imidazole group. In addition, the catalytic activity of the complex on the three‐component condensation of hydrazine hydrate with phthalic anhydride and dimedone to obtain 2H–indazolo[2,1‐b]phthalazine‐triones was investigated. Furthermore, in‐vitro antimicrobial studies were performed that indicated the great antibacterial activities of the Ni(II) complex against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus cereus bacteria.     

Binary teaching-learning-based optimization algorithm is used to investigate the superscattering plasmonic nanodisk

A new efficient binary optimization method based on Teaching-Learning-Based Optimization (TLBO) algorithm is proposed to design an array of plasmonic nanodisks in order to achieve maximum scattering coefficient spectrum. In binary TLBO (BTLBO), a group of learner consists of a matrix with binary entries; control the presence (‘1’) or the absence (‘0’) of nanodisks in the array. Simulation results show that scattering coefficient strongly depends on the localized position of nanoparticles and non-periodic structures have more appropriate response in term of scattering coefficient. This approach can be useful in optical applications such as plasmonic nanoantennas.     

Tetrameric DABCO–Bromine Complex: A Novel Reagent for Regeneration of Carbonyl Compounds From Aldoximes and Ketoximes

An efficient and convenient conversion of aldoximes and ketoximes to the corresponding carbonyl compounds with tetrameric DABCO–bromine complex is reported.     

Surface modification of cellulose nanocrystal with chitosan oligosaccharide for drug delivery applications

A novel drug delivery system based on two of the most abundant natural biopolymers was developed by modifying the surface of oxidized cellulose nanocrystal (CNC) with chitosan oligosaccharide (CS_OS). First, the primary alcohol moieties of CNC were selectively oxidized to carboxyl groups using the 2,2,6,6-tetramethylpiperidine-1-oxyl radical catalyst. The amino groups of CS_OS were then reacted with carboxylic acid groups on oxidized CNC (CNC-OX) via the carbodiimide reaction using N-hydroxysuccinimide and 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide as coupling agents. Successful grafting of CS_OS to CNC-OX was confirmed by infrared spectroscopy, thermogravimetry, potentiometric titration, and zeta potential measurements. The grafting resulted in a conversion of ~90 % carboxyl groups on CNC-OX and the degree of substitution was 0.26. CNC–CS_OS nanoparticles showed a binding efficiency of 21.5 % and a drug loading of 14 % w/w. A drug selective electrode was used to directly measure the concentration of procaine hydrochloride released from CNC–CS_OS particles. The in vitro drug release was studied at pH 8 and the nanoparticles revealed a fast release of up to 1 h, which can be used as biocompatible and biodegradable drug carriers for transdermal delivery applications.     

Development of <Superscript>111</Superscript>In labeled insulin for receptor imaging/therapy

In order to target insulin receptors in various diabetic and insulinoma conditions, human recombinant insulin was successively labeled with [¹¹¹In]-indium chloride after conjugation with freshly prepared cyclic DTPA-dianhydride (ccDTPA). The best results of the conjugation were obtained by addition of 0.5 mL of an insulin pharmaceutical solution (5 mg/mL, in phosphate buffer, pH 8) to a glass tube pre-coated with DTPA-dianhydride (0.01 mg) at 25 °C with continuous mild stirring for 30 minutes. Radio-thin layer chromatography (RTLC), instant thin layer chromatography (ITLC) and high performance liquid chromatography (HPLC) have shown an overall radiochemical purity of higher than 93% at optimized conditions (specific activity = 550–750 MBq/mg, radiochemical yield =81%). The white blood cell labeling capacity of the tracer was determined up to 4 hours at 37 °C. Preliminary in vivo studies in normal rat model was performed to determine the biodistribution of the radiotracer up to 48 hours. It showed a high liver and spleen uptake of the tracer which is consistent with other reported radiolabeled insulins. SPECT images have also shown high liver accumulation of the tracer.     

Equiconvergence of some complex interpolatory polynomials

Summary Walsh showed the close relation between the Lagrange interpolant in then ^th roots of unity and the corresponding Taylor expansion for functions belonging to a certain class of analytic functions. Recent extensions of this phenomena to Hermite interpolation and other linear processes of interpolation have been surveyed in [3, 5]. Following a recent idea of L. Yuanren [7], we show how new relations between other linear operators can be derived which exhibit Walsh equiconvergence.Dedicated to R. S. Varga on the occasion of his sixtieth birthdayThese authors were supported by NSERC A3094     

Optimization of a novel method based on solidification of floating organic droplet by high-performance liquid chromatography for evaluation of antifungal drugs in biological samples

In this study, a simple, rapid, and highly efficient liquid-phase microextraction method based on solidification of floating organic droplet was coupled with high performance liquid chromatography-photo diode array detection (HPLC-PDA) for determination of ketoconazole, clotrimazole, and miconazole as antifungal drugs. Central composite design (CCD) was used for optimization of several factors affecting the extraction efficiency. The optimized conditions were established to be 550 rpm for stirring rate, 35 min for extraction time, 57 °C for extraction temperature, 8.5 for solution pH, 10 μl for organic solvent volume, and 7% (w/v) of NaCl for ionic strength. Limit of detections (LODs) of the extraction method ranged from 0.01 to 0.1 μg L⁻¹ and the linear dynamic ranges (LDRs) ranged from 0.1 to 300 μg L⁻¹ for the three antifungal drugs. Relative standard deviations (RSDs) of the proposed method were 5-11%. Preconcentration factors in the range of 306-1350 were obtained at extraction time of 35 min. Finally, performance of the proposed method was evaluated for the extraction and determination of the drugs’ levels in microgram per liter in samples and satisfactory results were obtained.