Synthesis,spectral, thermal and structural characterization of {[Cu(H2O)3][Cu(MAL)2] · 2H2O}∞ and [Cu(MAL)(TEA)] · H2O (MAL = malonate and TEA = triethanolamine)

A polymeric malonato-bridged copper(II) complex, {[Cu(H₂O)₃][Cu(MAL)₂]· 2H₂O}, and a mononuclear malonato-copper(II) complex with triethanolamine, [Cu(MAL)(TEA)]·H₂O, have been prepared and characterized by elemental analyses, i.r., u.v.–vis, magnetic measurements and single crystal X-ray diffraction. The polymeric complex consists of one-dimensional chains containing the MAL bridged [Cu(H₂O)₃]²⁺ and [Cu(MAL)₂]^2– ions and each MAL ligand simultaneously exhibits chelating bidentate (at one copper atom) and bridging (at the adjacent copper atom) coordination modes. The intrachain Cu1...Cu2 separation is 4.963 Å and the polymeric complex exhibits antiferromagnetic behaviour. In the mononuclear complex, the copper(II) ion is octahedrally coordinated by one bidentate MAL and one tetradentate neutral TEA ligands. The i.r. spectra and thermal decompositions of both complexes are described.     

Heavy Metal Removal from Synthetic Solutions with Magnetic Beads Under Magnetic Field

The aim of this study is to prepare magnetic beads which can be used for the removal of heavy metal ions from synthetic solutions. Magnetic poly(ethylene glycol dimethacrylate‐vinyl imidazole) [m‐poly(EGDMA‐VIM)] beads were produced by suspension polymerization in the presence of magnetite Fe₃O₄ nano‐powder. The specific surface area of the m‐poly(EGDMA‐VIM) beads was found to be 63.1 m²/g with a size range of 150–200 µm in diameter and the swelling ratio was 85%. The average Fe₃O₄ content of the resulting m‐poly(EGDMA‐VIM) beads was 12.4%. The maximum binding capacities of the m‐poly(EGDMA‐VIM) beads were 32.4 mg/g for Cu²⁺, 45.8 mg/g for Zn²⁺, 84.2 mg/g for Cd²⁺and 134.5 mg/g for Pb²⁺. The affinity order on mass basis is Pb²⁺>Cd²⁺>Zn²⁺>Cu²⁺. Equilibrium data agreed well with the Langmuir model. pH significantly affected the binding capacity of the magnetic beads. Binding of heavy metal ions from synthetic wastewater was also studied. The binding capacities were 26.2 mg/g for Cu²⁺, 33.7 mg/g for Zn²⁺, 54.7 mg/g for Cd²⁺ and 108.4 mg/g for Pb²⁺. The magnetic beads could be regenerated up to about 97% by treating with 0.1 M HNO₃. These features make m‐poly(EGDMA‐VIM) beads a potential candidate for support of heavy metal removal under magnetic field.     

Anodic Voltammetric Determination of an Atypical Antipsychotic Drug Amisulphide in Pharmaceutical Dosage Forms Using Electrochemical fsDNA Biosensor

Russian Journal of Electrochemistry - In this study, a new biosensor for amisulpride (ASP) determination is defined. The interaction between ASP and fish sperm double-stranded DNA (FSdsDNA) was...     

Multiwall-carbon nanotube/cobalt ferrite hybrid: Synthesis,magnetic and conductivity characterization

Functionalized multiwall carbon nanotubes (MWCNT-COOH) were decorated with crystalline cobalt ferrite nanoparticles (CoFe₂O₄ NPs) by co-precipitation reaction to form MWCNT-COOH/CoFe₂O₄ hybrid. The hybrid was characterized by X-ray diffraction analysis, transmission electron microscopy (TEM), Fourier transfom infrared spectroscopy and vibrating sample magnetometry. The results confirmed that MWCNTs and CoFe₂O₄ NPs coexisted in the hybrid. The TEM results showed a thick layer of CoFe₂O₄ was intimately connected to the surface of MWCNTs. The saturation magnetization value of the hybrid was 11.5 emu/g. There has been a high frequency fluctuation in conductivity, however, above all dc conductivity changes and resulting activation energy is calculated from the Arrhenius plots. It is found to vary with the temperature regions. This can be attributed to the existence of a conventional temperature independent tunneling conduction mechanism, which can be also explained that the metallic conduction is a dominant mechanism around room temperature. The ac conductivity of MWCNT-COOH/CoFe₂O₄ hybrid might also be a consequence of the predictions of the universal dynamic response and the ‘n’ power exponents could be determined with lower concentration of the addition in the hybrids.     

DRBEM solution of biomagnetic fluid flow and heat transfer in cavities-CMMSE2016

In this paper, we investigate the fully developed, laminar, forced convection flow of an electrically non-conducting, viscous, biomagnetic fluid in the 2D cross-section (cavity) of a long impermeable pipe. The fluid is under the influence of a point magnetic source placed below the cavity. The dual reciprocity boundary element method (DRBEM) with constant and linear elements is used for solving the governing equations resulting from the Navier–Stokes and energy equations together with magnetization and buoyancy forces. The fundamental solution of Laplace equation is made use of converting differential equations to boundary integral equations by taking all the terms other than Laplacian as inhomogeneity in the Poisson’s equations for the velocity components, pressure and the temperature of the fluid. The unknown pressure boundary conditions are approximated through momentum equations by using finite difference approximation for the pressure gradients and DRBEM coordinate matrix for the other terms. All the space derivatives are also calculated by DRBEM coordinate matrix which is one of the main advantages of DRBEM. Pipe axis velocity is also computed. The effects of magnetization and the buoyancy force on the fluid with or without viscous dissipation term in the energy equation are investigated in square and lid-driven cavities for several values of magnetic (Mn) and Rayleigh (Ra) numbers. It is observed that the flow and heat transfer are significantly affected with increasing values of Mn and Ra. DRBEM gives small sized linear systems due to its boundary only nature at a considerably low computational expense.     

A One‐Dimensional Pyrazine Bridged Copper(II)‐Saccharinato Coordination Polymer

A one‐dimensional copper(II) complex {[Cu(sac)₂(μ‐pyz)(H₂O)]·H₂O}_n ( 1 ) (pyz = pyrazine, and sac = saccharinate) has been synthesized and characterized by elemental analysis, IR spectroscopy, thermal and single crystal X‐ray analyses. Complex 1 crystallizes in the triclinic space group . The [Cu(sac)₂(H₂O)] units are bridged by pyz leading to a one‐dimensional alternating chain in which the copper(II) ions exhibit a distorted square–pyramidal coordination of CuN₄O. The intradimer Cu···Cu distance is 6.881Å, while interdimer Cu···Cu distance is 7.066Å. The supramolecular interactions are mainly controlled by the sac anion and water molecules. The individual chains are linked by strong OW–H···O(sac) hydrogen bonds into a two‐dimensional layers, which are further arranged in a three‐dimensional supramolecular network by aromatic π(sac)···π(sac) stacking interactions and CH···π(pyz) interactions. Thermal analysis of complex 1 shows that the decompositions of the aqua, pyz and sac ligands are observed as distinct steps on the DTA and TG curves.     

Preparation and conductivities of polyacrylic acid/polyvinylimidazole grafted and ungrafted iron oxide nanocomposite polymer electrolytes

Nanocomposites of Polyacrylic acid/polyvinylimidazole (PAA/PVI) with grafted and ungrafted iron oxide nanoparticles were prepared by a Reflux method. The Fe₃O₄ nanoparticles with 10 nm average diameter were synthesized by controlled co-precipitation and silanization of Si-PVI on Fe₃O₄ was used to obtain the grafted ones. Grafting becomes important at composites of less PVI that cause drastic decreases in AC conductivity. The content of PVI has important effects on the conductivity mechanism of these composites. The effect of grafting and Polyacrylic acid/polyvinylimidazole molar ratio on the conduction mechanism were studied. The conduction mechanism of iron oxide nanocomposites can be adjusted by changing molar ratio of Polyacrylic acid/polyvinylimidazole and grafting of Fe₃O₄ NPs.      

Measurement of the Antipsychotic Clozapine Using Reduced Graphene Oxide Nanocomposites-Au/Pd/Pt Electrodes

Enhanced methods of drug monitoring are required to support the individualization of therapeutic drug dosing. Clozapine is one of the most important medications for managing schizophrenia, and timely measurement of serum clozapine levels has been identified as a barrier to the broader use of clozapine. For the first time, reduced graphene oxide nanocomposites were used to construct an electrochemical clozapine (Clz) sensor. The Reduced graphene oxide (Rego) nanocomposites were synthesized and characterized by using X-Ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM) techniques. The Clz sensing electrode was fabricated by drop coating of Rego nanocomposites suspension and Nafion solution on the pencil graphite electrode, respectively. The electrochemical behavior and influence of various physicochemical parameters of sensing electrodes were investigated by using cyclic voltammetry (CV) and differential voltammetry (DPV) techniques. The designed sensor displayed decent linear range, detection limit, reproducibility, and reusability results. Under optimum experimental parameters a linear dynamic range of 0.05–10 μM clozapine was observed with actual detection limit of 50 nM. Furthermore, the designed sensing electrode was used to measure the amount of Clz in real samples.     

A Comparative Study of Receptor-Targeted Magnetosome and HSA-Coated Iron Oxide Nanoparticles as MRI Contrast-Enhancing Agent in Animal Cancer Model

Magnetosomes are specialized organelles arranged in intracellular chains in magnetotactic bacteria. The superparamagnetic property of these magnetite crystals provides potential applications as contrast-enhancing agents for magnetic resonance imaging. In this study, we compared two different nanoparticles that are bacterial magnetosome and HSA-coated iron oxide nanoparticles for targeting breast cancer. Both magnetosomes and HSA-coated iron oxide nanoparticles were chemically conjugated to fluorescent-labeled anti-EGFR antibodies. Antibody-conjugated nanoparticles were able to bind the MDA-MB-231 cell line, as assessed by flow cytometry. To compare the cytotoxic effect of nanoparticles, MTT assay was used, and according to the results, HSA-coated iron oxide nanoparticles were less cytotoxic to breast cancer cells than magnetosomes. Magnetosomes were bound with higher rate to breast cancer cells than HSA-coated iron oxide nanoparticles. While 250 μg/ml of magnetosomes was bound 92 ± 0.2%, 250 μg/ml of HSA-coated iron oxide nanoparticles was bound with a rate of 65 ± 5%. In vivo efficiencies of these nanoparticles on breast cancer generated in nude mice were assessed by MRI imaging. Anti-EGFR-modified nanoparticles provide higher resolution images than unmodified nanoparticles. Also, magnetosome with anti-EGFR produced darker image of the tumor tissue in T2-weighted MRI than HSA-coated iron oxide nanoparticles with anti-EGFR. In vivo MR imaging in a mouse breast cancer model shows effective intratumoral distribution of both nanoparticles in the tumor tissue. However, magnetosome demonstrated higher distribution than HSA-coated iron oxide nanoparticles according to fluorescence microscopy evaluation. According to the results of in vitro and in vivo study results, magnetosomes are promising for targeting and therapy applications of the breast cancer cells.     

Hydroxyl functionalized thermosensitive microgels with quadratic crosslinking density distribution

N-isopropylacrylamide (NIPA) based uniform thermosensitive microgels were synthesized by dispersion polymerization by using relatively hydrophilic crosslinking agents with hydroxyl functionality. Glycerol dimethacrylate (GDMA), pentaerythritol triacrylate (PETA) and pentaerythritol propoxylate triacrylate (PEPTA) were used as crosslinking agents with different hydrophilicities. A protocol was first proposed to determine the crosslinking density distribution in the thermosensitive microgel particles by confocal laser scanning microscopy (CLSM). The microgels were fluorescently labeled by using hydroxyl group of the crosslinking agent. The CLSM observations performed with the microgels synthesized by three different crosslinking agents showed that the crosslinking density exhibited a quadratic decrease with the increasing radial distance in the spherical microgel particles. This structure led to the formation of more loose gel structure on the particle surface with respect to the center. Then the use of hydrophilic crosslinking agents in the dispersion polymerization of NIPA made possible the synthesis of thermosensitive microgels carrying long, flexible and chemically derivatizable (i.e., hydroxyl functionalized) fringes on the surface by a single-stage dispersion polymerization. The microgels with all crosslinking agents exhibited volume phase transition with the increasing temperature. The microgel obtained by the most hydrophilic crosslinking agent, GDMA exhibited higher hydrodynamic diameters in the fully swollen form at low temperatures than those obtained by PETA and PEPTA. Higher hydrodynamic size decrease from fully swollen form to the fully shrunken form was also observed with the same microgel.