Determination of vanadium in serum by pre-irradiation and post-irradiation chemistry and neutron activation analysis

Vanadium in serum was investigated by pre-irradiation chemistry neutron activation analysis employing anion exchange chromatography and post-irradiation neutron activation employing solvent extraction techniques. From a comparison of these techniques it is concluded that vanadium is present in human serum in the sub-ppb range.     

An Approximation of the Analytical Solution of the Linear and Nonlinear Integro-Differential Equations by Homotopy Perturbation Method

This paper aims to introduce an analytic technique, namely the Homotopy perturbation method (HPM) for the solution of integro-differential equations. From the computational viewpoint, the comparison shows that the homotopy perturbation method is efficient and easy to use.     

An unexpected, novel, three-component reaction between isoquinoline, an isocyanide and strong CH-acids in water

An unexpected three-component condensation reaction between an isocyanide, isoquinoline and a strong CH-acid efficiently provides 1,2-dihydroisoquinoline derivatives in a one-pot reaction in water at 70 °C without using any catalyst.     

A New Approach for Optimization of Distributed Quantum Circuits

International Journal of Theoretical Physics - In the present work, a novel approach was proposed to optimize the teleportation cost in Distributed Quantum Circuits (DQCs) by applying a new...     

New acetylated flavone C-glycosides from Iris lactea

Chemical investigation of the aerial parts of Iris lactea afforded three new flavone C-glycosides including 4?-O-acetyl-embinin (1), 2?,4?-O-diacetyl-embinin (2) and 6″,4?-O-diacetyl-embinin (3) along with the known analogue embinin (4). Their structures were elucidated by 1D and 2D NMR spectroscopic analysis as well as by HRESIMS data. The sugars were characterized following acid hydrolysis of the respective glycosides and TLC analysis compared to known standards. Duplicated signals can be observed in the NMR spectra, indicating the presence of rotamers caused by rotational hindrance around the glycosyl-flavone CC linkage. All isolated compounds were tested for their antimicrobial and cytotoxic activities but found to be inactive.     

PVT properties of imidazolium-, phosphonium-, pyridinium- and pyrrolidinium-based ionic liquids using critical point constants

Song and Mason equation of state (EOS) with a simple modification has been extended to modelling PVT properties of ionic liquids (ILs). The considered ILs are [C₁mim][MeSO4], [C₁mim][CH₃OC₂H₅SO₄], [C₁mim][(CH₃)₂PO₄], [C₂mim][MeSO4], [C₂mim][BF₄], [C₂mim][SCN], [C₂eim][NTf₂], [C₄mim][C(CN)₃], [C₄mim][CF₃SO₃], [C₄mim][SCN], [C₅mim][NTf₂], [C₈mim][NTf₂], [(C₆H₁₃)₃P(C₁₄H₂₉)][Cl], [(C₆H₁₃)₃P(C₁₄H₂₉)][NTf₂], [(C₆H₁₃)₃P(C₁₄H₂₉)][Ac], [C₃mpyr][NTf₂], [C₄mpyr][NTf₂] and [Py][C₂H₅OC₂H₄SO₄]. Three temperature-dependent parameters in the proposed EOS have been scaled as functions of reduced temperature with the use of the law of corresponding states. It is shown that the knowledge of just critical temperature and critical density is sufficient to predict the PVT properties of these ILs. The overall average absolute deviation of calculated densities from literature values for 1347 data points of 18 ILs was found to be 0.58%. The predicted density of ILs from proposed EOS has been compared with those obtained by other literature work. Moreover, we indicate that the Zeno line regularity can well be predicted by proposed model for ILs.     

Preparation of different graphene nanostructures for hydrogen adsorption

In this study, different types of graphene were synthesized to investigate hydrogen adsorption capacity at different pressures (0–34 bar) at room temperature (298 K). Graphene and nanoporous graphene were prepared by Chemical Vapor Deposition (CVD) method, using methane as a carbon source at a temperature of 900 °C over copper plates and nickel oxide nanocatalyst. The nickel oxide nanocatalyst was prepared by sol–gel method, whereas graphene oxide was prepared through modified Hummer's method. The products were characterized by X‐ray diffraction, field emission‐scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller and Raman spectroscopy. The adsorption of hydrogen was done by volumetric method. High adsorption capacity was achieved in nanoporous graphene because of its high pore volume (2.11 cm³/g) and large specific surface area (850 m²/g). Hydrogen adsorption values for nanoporous graphene, graphene and graphene oxide were determined as 2.56, 1.70 and 0.74 wt%, respectively. In addition, the hydrogen adsorption of graphene nanostructures fitted nicely to the selected two‐parameter and three‐parameter adsorption isotherm models. The adsorption isotherm model coefficients have been found for a 0–34 bar pressure range. The parameter values for all adsorbents showed proper conformity to the model and experimental data. Copyright © 2016 John Wiley & Sons, Ltd.     

Atom transfer radical polymerization of methyl methacrylate using copper-based homogeneous and heterogeneous catalysts

This study aimed at polymerization of methyl methacrylate with novel catalysts in the atom transfer radical polymerization (ATRP) condition at 90 °C. This was accomplished using CuBr/N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (CuBr–AEAPTMS) as a homogeneous catalyst and one time with CuBr@AEAPTMS/SBA-15 as a heterogeneous catalyst. Catalysts were characterized using TGA, FT-IR, and UV–Vis spectroscopy. The structural analysis of the polymer was carried out by ¹³C NMR spectroscopy and GPC. Three characteristic parts of polymer produced by ATRP method including the initiator, monomer units, and end group was shown in ¹³C NMR spectra. In addition, the presence of C–Br unit showed that the polymerization process is alive. The ¹H NMR analysis was used for kinetic investigation of methyl methacrylate polymerization with homogeneous and heterogeneous catalysts that showed high monomer conversion (98 and 90% after 35 min, respectively) and good control of molecular weight with a dispersity (Р= 1.5–1.7). In addition, the plot of ln ([monomer]₀/[monomer] _t ) versus time gave linear relationships indicating a constant concentration of the propagating species throughout the polymerization. Finally, the results of the polymerization using heterogeneous catalyst compared with homogeneous catalyst revealed that it was according to ATRP method.     

Al(H_2PO_4)_3 as an Efficient and Reusable Catalyst for One-pot Three-component Synthesis of α-Amino Phosphonates under Solvent-free Conditions

Synthesis of α‐amino phosphonates is described under solvent‐free conditions at 100°C from reaction between aldehydes and amines in the presence of trialkyl phosphites using Al(H₂PO₄)₃ as an efficient and reusable heterogeneous catalyst. The advantages of this procedure are short reaction time, flexibility and having high to excellent yields.     

Promoter effect on the CO2-H2O formation during Fischer-Tropsch synthesis on iron-based catalysts

The effects of Mg, La and Ca promoters on primary and secondary CO_2 and H_2O formation pathways during Fischer-Tropsch synthesis on precipitated Fe/Cu/SiO_2 catalysts are investigated. The chemisorbed oxygen atoms in the primary pathway formed in the CO dissociation steps reacted with co-adsorbed hydrogen or carbon monoxide to produce H_2O and CO_2 , respectively. The secondary pathway was the water-gas shift reaction. The results indicated that the CO_2 production led to an increase in both primary and secondary pathways, and H_2 O production decreased when surface basicity of the catalyst increased in the order Ca >Mg >La.