Investigation and comparison of pristine/doped BN,AlN, and CN nanotubes as drug delivery systems for Tegafur drug: a theoretical study

Structural Chemistry - In this work, the potential of BN, AlN, and CN nanotubes as the drug delivery systems of Tegafur (TG) was investigated by the density functional theory (DFT). The doping...     

Ultrasensitive Simultaneous Quantification of Nanomolar Level of Cd and Zn by Cathodic Adsorptive Stripping Voltammetry in Some Real Samples

A novel, simple and sensitive adsorptive stripping voltammetry method was developed for simultaneous determination of Cd and Zn using N‐Nitrozo‐N‐phenylhydroxylamine (Cupferron) as a selective complexing agent. Cadmium and zinc metals gave peaks that were distinctly separated by 450–1200 mV, allowing their determination over a wide range of concentrations. The influence of pH and the nature of supporting electrolytes, concentration of ligand, preconcentration time and applied potential were investigated. The detection limits were 0.058 ng/mL for Zn and 0.092 ng/mL for Cd, and the RSD at a concentration level of 50 ppb, were 1.8–2.1 % for both zinc and cadmium, respectively. The method was applied to the determination of cadmium and zinc in blood, drug, food and water samples with the satisfactory results.     

A New Trinuclear Zn(II) Complex {[Zn(μ-ONN)(μ<Subscript>2</Subscript>-O)(μ-OO)]<Subscript>2</Subscript>Zn}: Synthesis,Characterization, Thermal Decomposition and Antibacterial Activity

New centrosymmetric trinuclear zinc(II) complex {[Zn(μ-ONN)(μ₂-O)(μ-OO)]₂Zn} has been synthesized by the reaction of a potentially ONN tridentate Schiff base ligand, and N,N-dimethylethylendiamin, with Zn(OAc)₂·2H₂O in methanol, in the refluxed conditions and characterized by elemental analysis, FT-IR and UV–Vis spectroscopy. Single crystal X-ray structure analysis reveals a trinuclear complex {[Zn(μ-ONN)(μ₂-O)(μ-OO)]₂Zn} with zinc(II) ions connected by three different bridges, (μ-ONN) of the Schiff base ligand, μ₂-O and μ-OO of the acetate. The complex is centrosymmetric, with one of the Zn atoms located at the inversion center. While the central Zn(II) ion is six-coordinated, the coordination number of the other Zn(II) ions is five. Finally, the {[Zn(μ-ONN)(μ₂-O)(μ-OO)]₂Zn} complex was thermally decomposed in air at 700 °C resulted in ZnO nano crystalites with the average size of 42 nm. The antibacterial activity of ligand and its zinc(II) complex were tested against gram-positive and gram-negative bacteria. The ligand showed higher activity than its zinc(II) complex.     

A new scheme for solving nonlinear Stratonovich Volterra integral equations via Bernoulli’s approximation

In this paper, an efficient method for solving nonlinear Stratonovich Volterra integral equations is proposed. By using Bernoulli polynomials and their stochastic operational matrix of integration, these equations can be reduced to the system of nonlinear algebraic equations with unknown Bernoulli coefficient which can be solved by numerical methods such as Newton’s method. Also, an error analysis is valid under fairly restrictive conditions. Furthermore, in order to show the accuracy and reliability of the proposed method, the new approach is compared with the block pulse functions method by some examples. The obtained results reveal that the proposed method is more accurate and efficient than the block pulse functions method.     

Nano-Fe3O4@SiO2–TiCl3 as a novel nano-magnetic catalyst for the synthesis of 4H-pyrimido[2,1-b]benzothiazoles

Research on Chemical Intermediates - Fe3O4@SiO2–TiCl3 NPs, a novel core shell catalyst, was synthesized via preparing Fe3O4@SiO2 as a magnetic support followed by treatment with titanium...     

Calibration-free laser-induced plasma analysis of a metallic alloy with self-absorption correction

Identification and concentration measurement of constituent elements of a metallic alloy is demonstrated by calibration-free laser-induced breakdown spectroscopy (CF-LIBS) according to a special peak intensity-based model and considering the self-absorption effect. In this procedure, which is based on the line pair ratio method, the effect of line widths, though needs to be theoretically considered, may be approximately ignored. This is mainly true for the multiplet lines, but this property, in the case of some generic spectral lines in a measured spectrum, can be sometimes regarded. Initially, the optical penetration depth and therefrom self-absorption coefficient of each selected spectral line is calculated using the experimental (self-absorbed) intensity of the line. Then, the true (non-self-absorbed) intensity, which is basis of the conventional CF-LIBS calculation, is obtained through a recursive algorithm implemented by the MATLAB programming. In the experimental examination, the recorded spectrum reflects that the metallic alloy is consisted of gold, copper and silver. The concentration of elements is calculated with and without regarding self-absorption correction using 27 trios of spectral lines related to the elements. The average concentrations signify that the measurement error relative to the certified value for the concentration of the gold is modified from 3.56 % in the normal way to 0.34 % after applying self-absorption correction.     

Synthesis of gold nanoparticles decorated on sulfonated three‐dimensional graphene nanocomposite and application as a highly efficient and recyclable heterogeneous catalyst for Ullmann homocoupling of aryl iodides and reduction of p‐nitrophenol

Gold nanoparticles were decorated onto sulfonated three‐dimensional graphene (3DG‐SO₃H) through spontaneous chemical reduction of HAuCl₄ by 3DG‐SO₃H. This nanocomposite exhibited excellent catalytic activity for the synthesis of symmetric biaryls via the Ullmann homocoupling of aryl iodides in an aqueous medium. Additionally, this nanocomposite was used as a catalyst for the reduction of p‐nitrophenol to p‐aminophenol. The catalyst could be used more than six times successively without significant deactivation.     

Preparation of Mn-doped ZnO nanostructured for photocatalytic degradation of Orange G under solar light

Research on Chemical Intermediates - In this study, undoped ZnO and Mn-doped ZnO nanostructured with different doping concentrations were prepared through a facile chemical method. Then, X-ray...     

Nanosized aptameric cavities imprinted on the surface of magnetic nanoparticles for high-throughput protein recognition

The authors introduce a new kind of surface artificial biomimetic receptor, referred to as aptameric imprinted polymer (AIP), for separation of biological macromolecules. Highly dispersed magnetic nanoparticles (MNPs) were coated with silica and then functionalized with methacrylate groups via silane chemistry. The aptamer was covalently immobilized on the surface of nanoparticles via a “thiol-ene” click reaction. Once the target analyte (bovine serum albumin; BSA) has bound to the aptamer, a polymer is created by 2-dimensional copolymerization of short-length poly(ethylene glycol) and (3-aminopropyl)triethoxysilane. Following removal of BSA from the polymer, the AIP-MNPs presented here can selectively capture BSA with a specific absorbance (κ) as high as 65. When using this AIP, the recovery of BSA from spiked real biological samples is >97%, and the adsorption capacity is as high as 146 mg g^?1. In our perception, this method has a wide scope in that it may be applied to the specific extraction of numerous other biomolecules.

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Graphical abstract Schematic presentation of the AIP (aptamer-imprinted polymer) introduced here. The surface of silica coated magnetic nanoparticles is modified with a polymer that is covalently modified with an aptamer against bovine serum albumin (BSA).