Maximal Subgroups of Subnormal Subgroups of GL n (D) with Finite Conjugacy Classes

Let D be an infinite division ring. A famous result due to Herstein says that every noncentral element of D has infinitely many conjugates in D. So, if D* is an FC-group, then D is a field. Now let N be a subnormal subgroup of GL _n (D), where n ≥ 1, and M a maximal subgroup of N. In this article, we prove that if M is an FC-group, then M is contained in the multiplicative group of some subfield of M _n (D).     

1-Butyl-3-methylimidazolium Hydrogen Sulfate [bmim]HSO4: An Efficient Reusable Acidic Ionic Liquid for the Formylation of Alcohols

1-Butyl-3-methylimidazolium hydrogen sulfate [bmim]HSO4 as an acidic ionic liquid was prepared and used as a catalyst for the formylation of alcohols with ethyl formate at room temperature with good to excellent yields. A good selectivity was observed for the formylation of primary alcohols in the presence of tertiary alcohols.     

Synthesis and properties of the first Möbius annulenes

Heilbronner in 1964 predicted that annulenes with ".. a planar perimeter of N=4r AO's, which would yield an open shell configuration when occupied by 4r electrons, can be twisted into a closed shell M?bius strip perimeter without loss in pi electron energy". We have been able to synthesize the first [4n]annulene with such a M?bius topology and now present further M?bius isomers and the details of their preparation as stable compounds. To address the question whether the twist in the pi system has an effect on the properties we systematically investigate energy, geometry and magnetic parameters of a large number isomers of [16]annulenes. The M?bius twisted annulenes are consistently more aromatic than the non-twisted isomers. This is true for the parent as well as our benzoannelated systems. Our results are in contrast to those published recently by C. Castro, W. L. Karney, P. von R. Schleyer et al.     

Band gap determination by absorption spectrum fitting method (ASF) and structural properties of different compositions of (60−x) V2O5–40TeO2–xSb2O3 glasses

Glasses with compositions (60?x) V₂O₅–40TeO₂–xSb₂O₃ with 0 ? x ? 10 (in mol%) have been prepared using usual melt quenching method. The position of the absorption edge and hence the values of the optical band gap was found to depend on the glass composition. Using the Tauc model, the absorption spectrum fitting method (ASF) was employed to obtain the optical band gap. This method requires only the measurement of the absorbance spectrum of the sample. For each sample, the width of the band tail was determined. Also, the density and glass transition temperature values indicate that the rigidity and packing of the samples increase with increase in Sb₂O₃ concentration.     

Mixed convection heat transfer of a nanofluid in a closed elbow-shaped cavity (CESC)

Journal of Thermal Analysis and Calorimetry - The current survey’s primary purpose is to conduct the computational modeling of laminar mixed convection heat transfer of nanofluids inside a...     

Synthesis of some mono- and bis-spiro-β-lactams of benzylisatin

Some new mono- and bis-spiro-β-lactams of benzylisatin were prepared by Staudinger’s ketene-imine [2+2] cycloaddition reaction. The cycloadducts were characterized by spectral data including ¹H NMR, ¹³C NMR, IR and mass spectra. The configuration of benzylisatin and one of mono-spiro-β-lactams (5a) was established by X-ray crystal analysis.     

Solvent-assisted intramolecular proton transfer in thiopurinol: application of M06-2X functional

All available conformers of tisopurine as an important pharmaceutical molecule are optimized and frequency calculations calculated at M06-2X/6-311++G(2d,2p) level of theory. These conformers are classified in 22 different tautomers, tautomer Z showing the most stable tautomer in the gas phase. Effects of four different solvents on the most stable conformer of each tautomer is calculated. Solvents cause stabilization of all conformers and relative solvent stabilization is as follows: water > DMSO > acetone > toluene. Energy profile for such stabilization is illustrated and mechanism of proton transfer studied at the same level of theory. Solvent-assisted proton transfer performed when water and methanol used as solvents. Results indicate that explicit solvent effect has much more stabilization on tautomerization processes compared to implicit solvent effect.     

Fatty Acid Binding to Human Serum Albumin in Blood Serum Characterized by EPR Spectroscopy

One of the functions of Human Serum Albumin (HSA) is binding and transport of fatty acids. This ability could be altered by the presence of several blood components such as toxins or peptides – which in turn alters the functionality of the protein. We aim at characterizing HSA and its fatty acid binding in native serum environment. Native ligand binding and deviations from normal function can be monitored by electron paramagnetic resonance (EPR) spectroscopy using spin labeled fatty acids (FAs). Blood serum from healthy individuals is used to examine healthy HSA in its natural physiological conditions at different loading ratios of protein to FAs. Among the EPR spectroscopic parameters (like hyperfine coupling, line shape, rotational correlation time and population of different binding sites) the rotational correlation time is found to differ significantly between binding sites of the protein, especially at loading ratios of four FAs per HSA. Although differences are observed between individual samples, a general trend regarding the dynamics of healthy HSA at different loading ratios could be obtained and compared to a reference of purified commercially available HSA in buffer.     

Experimental study of a large plastic scintillator response with different reflective coverings based on digital pulse processing method

Journal of Radioanalytical and Nuclear Chemistry - Digital pulse processing methods have various applications in radiation spectroscopy due to their unique properties. Here, the effect of light...     

Diminishing vortex intensity and improving heat transfer by applying magnetic field on an injectable slip microchannel containing FMWNT/water nanofluid

In this study, heat transfer and entropy generation were investigated in a microchannel containing FMWNT/water nanofluids given the slip condition. The main focus was on utilizing injection technique in the presence of the magnetic field. The injection from the upper high-temperature wall was incorporated into the flow field. Injection at high Reynolds number causes vortex formation, which ultimately reduces local heat transfer in the adjacent injection zone. By applying the magnetic field, the vortex intensity as well as boundary layer thickness was diminished which in turn improved the heat transfer. Based on numerical results, at higher nanoparticle volume fraction, the effect of the magnetic field on heat transfer enhancement was amplified. Moreover, at higher Reynolds numbers, the magnetic field efficacy is more obvious. The highest heat transfer occurred at the highest values of the Hartmann and Reynolds numbers and eventually the nanoparticle volume fraction. Owing to applying the magnetic field on the injectable microchannel containing nanofluid, heat transfer improvement can reach up to 79%. From the second law prospective, the entropy generation intensified by 82.8%.