Synthesis of 3‐Aryl‐2‐benzoylbenzofuran Derivatives using Manganese(III) Acetate–Mediated Addition of Dimedon to Chalcone Derivatives

3‐Aryl‐2‐benzoylbenzofurans were synthesized by the reaction of α‐carboradical produced from dimedon by oxidizing with manganese(III) acetate in acetic acid and the chalcone derivatives.     

Potassium–Tertiary Butoxide–Assisted Addition of Thioglicolic Acid to Chalcone Derivatives Under Solvent-Free Conditions

A series of chalcone derivatives containing thioglicolic acid (4a–j) was prepared by addition of thioglicolic acid to the chalcones (3a–j) in the presence of KOt-Bu under solvent-free conditions. The mechanistic pathway of the reaction can be explained by the Michael-type addition of thioglicolic acid to chalcone derivatives (3a–j).     

Synthesis of Terpenoid-Like Bischalcones from α- and β-Ionones and Their Biological Activities

Ionone-based terpenoid-like bischalcones (3a–h and 4a–h) were synthesized from the reaction of α- and/or β-ionones with aldehyde derivatives in excellent yields. The antibacterial activities of synthesized compounds were screened against human pathogenic micro-organisms by employing the disk-diffusion technique.     

Evaluation of high hydrostatic pressure effects on bovine red blood cells and platelets

The objective of this study was to investigate the effects of high hydrostatic pressure (HHP) on the stability of red blood cells (RBCs) and platelets. Bovine blood cells (n=5) were treated with the pressure of 55, 110, 154 and 220 MPa at 25 °C for 5 min. Light microscopy, atomic force microscopy and flow cytometry studies revealed that RBCs were morphologically stable up until the 220 MPa pressure treatments, at which surface modifications were observed. The platelets were found to be less stable than RBCs. HHP application did not cause any significant change in the signal intensity, band area and frequency values of the infrared bands with the exception that a significant variation was observed in the area of the cholesterol band. No statistically significant variations were observed in the secondary structure elements due to HHP treatment according to the artificial neural network study based on the FTIR data.     

Mussel Inspired Dynamic Cross‐Linking of Self‐Healing Peptide Nanofiber Network

A general drawback of supramolecular peptide networks is their weak mechanical properties. In order to overcome a similar challenge, mussels have adapted to a pH‐dependent iron complexation strategy for adhesion and curing. This strategy also provides successful stiffening and self‐healing properties. The present study is inspired by the mussel curing strategy to establish iron cross‐link points in self‐assembled peptide networks. The impact of peptide‐iron complexation on the morphology and secondary structure of the supramolecular nanofibers is characterized by scanning electron microscopy, circular dichroism and Fourier transform infrared spectroscopy. Mechanical properties of the cross‐linked network are probed by small angle oscillatory rheology and nanoindentation by atomic force microscopy. It is shown that iron complexation has no influence on self‐assembly and β‐sheet‐driven elongation of the nanofibers. On the other hand, the organic‐inorganic hybrid network of iron cross‐linked nanofibers demonstrates strong mechanical properties comparable to that of covalently cross‐linked network. Strikingly, iron cross‐linking does not inhibit intrinsic reversibility of supramolecular peptide polymers into disassembled building blocks and the self‐healing ability upon high shear load. The strategy described here could be extended to improve mechanical properties of a wide range of supramolecular polymer networks.     

Synthesis of silver nanoflakes on chitosan hydrogel beads and their antimicrobial potential

Abstract

The present study involves the fabrication of CH and CH-Ag hydrogel beads and the investigation of the antimicrobial properties. The beads were fabricated using a simple coacervation method. The successfully synthesized beads were characterized by UV-Vis and FTIR. The surface morphology, shape and diameter of the samples were determined by optical microscopy and SEM. The antimicrobial activities were determined against potential human pathogens including bacterial and fungal species. Our results demonstrated that beads can be utilized as potential materials for use in biomedical approaches including delivery systems and tissue engineering applications to prevent microbial contamination and to inhibit the growth of microorganisms.     

The integral invariants of parallel timelike ruled surfaces

In this paper, we first gave the parallel timelike ruled surface with a timelike ruling and its geometric invariants in terms of the main surface. We then obtained the integral invariants which are the pitch and the dual angle of pitch of the parallel timelike ruled surface with a timelike ruling and also the relations among them and integral invariants of the main surface.     

Comparing the development of the multiplication of fractions in Turkish and American textbooks

This study analyzed the methods used to teach the multiplication of fractions in Turkish and American textbooks. Two Turkish textbooks and two American textbooks, Everyday Mathematics (EM) and Connected Mathematics 3 (CM), were analyzed. The analyses focused on the content and the nature of the mathematical problems presented in the textbooks. The findings of the study showed that the American textbooks aimed at developing conceptual understanding first and then procedural fluency, whereas the Turkish textbooks aimed at developing both concurrently. The American textbooks provided more opportunities for different computational strategies. The solutions to most problems in all textbooks required a single computational step, a numerical answer, and procedural knowledge. Furthermore, compared with the Turkish textbooks, the American textbooks contained a greater number of problems that required high-level cognitive skills such as mathematical reasoning.     

Second and third-order nonlinear optical behavior of natural pigment: chlorophyll and crocin

To provide an insight into the microscopic second and third-order nonlinear optical (NLO) behavior of chlorophyll a and crocin, we have computed the electric dipole moments (μ), dispersion-free first hyperpolarizabilities (β), frequency-dependent first and second (γ) hyperpolarizabilities at 1064 nm wavelength area using time-dependent Hartree-Fock (TDHF) method. According to ab-initio calculation results, the examined compounds exhibit first and second hyperpolarizabilities with non-zero values, implying second and third-order NLO phenomena.     

Simultaneous Determination of Rosmarinic Acid and Protocatechuic Acid at Poly(o‐Phenylenediamine)/Pt Nanoparticles Modified Glassy Carbon Electrode

A system of Pt nanoparticles and poly(ortho‐phenylenediamine) film electrochemically deposited onto a glassy carbon electrode (GCE/PoPD/Pt) was fabricated. Scanning electron microscopy, Fourier‐transform infrared spectroscopy, and atomic force microscopy techniques were used to identify the surface characteristics of the composite electrode. The conductive polymers and Pt nanoparticles together resulted in a synergistic effect, and the new formed surface was highly active against polyphenolic structures. Rosmarinic acid (RA) and protocatechuic acid (PCA) are phenolic compounds found in plants, and they are used in many applications, particularly as pharmaceuticals. The GCE/PoPD/Pt was used for the simultaneous determination of RA and PCA in a pH 2.0 H₂SO₄ solution for the first time. The RA and PCA concentrations were determined using differential pulse voltammetry (DPV) and chronoamperometry. By the amperometry measurement, for RA and PCA, a linear relation was observed in the concentration ranges of 1–55 μmol L^?1 and 1–60 μmol L^?1, with detection limits of 0.5 μmol L^?1 and 0.6 μmol L^?1, respectively. In the simultaneous determination with DPV, the detection limits for both RA and PCA were calculated as 0.7 μmol L^?1. The GCE/PoPD/Pt was successfully used for the simultaneous determination of RA and PCA in a real sample, and its accuracy was verified by high‐performance liquid chromatography studies.