Synthesis of Some Novel Norbornene‐Fused Pyridazines as Potent Inhibitors of Carbonic Anhydrase and Acetylcholinesterase

The reaction of benzocyclic norbornene derivatives with tetrazines provided the 1,3‐dihydropyridazine derivatives as a single product. The dihydropyridazine derivatives have been dehydrogenated with phenyliodine bis(trifluoroacetate) to yield the corresponding pyridazines in a high yield. Two stable diazines, primary product of corresponding 1,4‐dihydropyridazine, were also isolated. Structures were then determined by ¹H‐NMR, and ¹³C‐NMR beside to elemental analyses. The novel pyridazine derivatives ( 8 , 9 ) efficiently inhibited the cytosolic human carbonic anhydrase isoenzymes I and II (hCA I and II). In addition, these novel pyridazine derivatives ( 8 , 9 ) were evaluated for their in vitro acetylcholinesterase inhibitory activity. Ligand–receptor interactions are tested using molecular docking simulations. Obtained docking scores are in good agreement with in vitro results.     

Investigation of structural,electronic and optical properties of pure and Ag‐doped TiO2 nanofibers fabricated by electrospinning

Pure and 1, 2, and 3 wt% Ag doped TiO₂ nanofibers were prepared by electrospinning method at different applied voltages and heights at a constant flow rate of 2 mL/h. Characterization of the prepared samples was performed by x‐ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microcopy (AFM),four point probe method (FPPM), the differential scanning calorimetry/the thermal gravimetric analysis (DSC/TGA), ultraviolet/visible spectrometry (UV/VIS), and energy dispersive X‐ray spectrometer (EDX). It was found that the thermally untreated pure TiO₂ nanofibers and thermally treated (at 500 °C) samples have the crystalline phase of anatase (A), and mixed anatase and rutile (A+R) phases, respectively. It was also observed that the content of the silver does not affect the crystal structure, but plays strengthening role in the rutile structure. SEM micrographs showed that all fabricated nanofiber samples have uniform morphologies, and AFM measurements indicated that the nanofibers were formed in three‐dimensional coils. The band gap values of the nanofiber samples obtained from UV/VIS measurements revealed that band gap values of the nanofiber samples decrease while the diameter of the nanofiber increases.     

Fabrication of collagen immobilized electrospun poly (vinyl alcohol) scaffolds

In the development of tissue engineering scaffolds, the interactions between material surface and cells play crucial roles. The biomimetic 3‐D scaffolds absolutely provide better results for fulfilling requirements such as porosity, interconnectivity, cell attachment and proliferation. In this study, 3‐D electrospun scaffolds were prepared by using an electrospinning technique. Photo cross‐linkable polyvinyl alcohol was used as a polymeric matrix. During the electrospinning, the nanofibers were cross‐linked with in situ ultraviolet radiation. The crosslinked polymer fibers were achieved in a simple process at a single step. Nanofiber surface was modified with collagen by a chemical approach. The chemical structures were proven by attentuated total reflectance Fourier transform infrared spectroscopy and proton nuclear magnetic resonance. The surface morphology of the nanofibers was characterized by scanning electron microscope (SEM). Morphological investigations show that the resulting nanofibrous matrix has uniform morphology with a diameter of 220–250 nm. In vitro attachment and growth of 3T3 mouse fibroblasts and human umbilical vein endothelial cells (ECV304) cells on polyvinyl alcohol‐based nanofiber mats were also investigated. Cell attachment, proliferation, and methylthiazole tetrazolium cytotoxicity assays indicated good cell viability throughout the culture time, which was also confirmed by SEM analysis. Copyright © 2015 John Wiley & Sons, Ltd.     

Statistical Approximation by Double Poisson–Cauchy Singular Integral Operators

In this paper we show that it is possible to approximate a continuous and 2π-periodic function on the disk centered at origin with radius π by means of double Poisson–Cauchy singular integral operators which do not need to be positive in general. Our results cover not only the classical approximation but also the statistical approximation process.     

Chiral resonant solitons in Chern–Simons theory and Broer–Kaup type new hydrodynamic systems

New Broer–Kaup type systems of hydrodynamic equations are derived from the derivative reaction–diffusion systems arising in SL(2, R) Kaup–Newell hierarchy, represented in the non-Madelung hydrodynamic form. A relation with the problem of chiral solitons in quantum potential as a dimensional reduction of 2 + 1 dimensional Chern–Simons theory for anyons is shown. By the Hirota bilinear method, soliton solutions are constructed and the resonant character of soliton interaction is found.     

Improved parallel preconditioners for multidisciplinary topology optimisations

Two commonly used preconditioners were evaluated for parallel solution of linear systems of equations with high condition numbers. The test cases were derived from topology optimisation applications in multiple disciplines, where the material distribution finite element methods were used. Because in this optimisation method, the equations rapidly become ill-conditioned due to disappearance of large number of elements from the design space as the optimisations progresses, it is shown that the choice for a suitable preconditioner becomes very crucial. In an earlier work the conjugate gradient (CG) method with a Block-Jacobi preconditioner was used, in which the number of CG iterations increased rapidly with the increasing number processors. Consequently, the parallel scalability of the method deteriorated fast due to the increasing loss of interprocessor information among the increased number of processors. By replacing the Block-Jacobi preconditioner with a sparse approximate inverse preconditioner, it is shown that the number of iterations to converge became independent of the number of processors. Therefore, the parallel scalability is improved.     

Energy in the Schwarzschild-de Sitter Spacetime

The energy (due to matter and fields including gravitation) of the Schwarzschild-de Sitter spacetime is investigated by using the Møller energy-momentum definition in both general relativity and teleparallel gravity. We found the same energy distribution for a given metric in both of these different gravitation theories. It is also independent of the teleparallel dimensionless coupling constant, which means that it is valid in any teleparallel model. Our results sustain that (a) the importance of the energy-momentum definitions in the evaluation of the energy distribution of a given spacetime and (b) the viewpoint of Lessner that the Møller energy-momentum complex is a powerfifi concept of energy and momentum.     

Role of the 30° Telescope in Evaluation of Laryngeal Masses During Direct Laryngoscopy

SUMMARY: Visualization of enlarged laryngeal lesions is the most important factor in choosing a surgical technique, especially for partial surgery. For this reason standard microlaryngoscopy, a computed tomography (CT) scan of the larynx, and 30 degrees telescopic microlaryngoscopy were compared during evaluation of the laryngeal ventricul and sub-glottic area. The histopatholgoical findings of the specimens collected under each modality were simultaneously compared. Comparison of the histopathological findings, which corresponded to inspection with the 30 degrees telescopic method, was more significant than with the use of standard microlaryngoscopy or the CT scan. The aim of the current study therefore was to determine the importance of the 30 degrees telescopic microlaryngoscopic method for the evaluation of the laryngeal ventricle and subglottic area.