New Heterocyclic Phosphorus Ylides: Synthesis,Crystal Structure,and Theoretical Calculation of Alkyl Substituted 3-(4-Benzoyl-1,5-diphenyl-2,3-dihydro-1H-pyrazol-3-yl)-3-oxo-2-(triphenylphosphoranylidene) Propanoates

Novel alkyl substituted 3-(4-benzoyl-1,5-diphenyl-2,3-dihydro-1H-pyrazol-3-yl)-3-oxo-2-(triphenylphosphoranylidene) propanoates (3) were synthesized from 4-benzoyl-1,5-diphenyl-1H-pyrazole-3-carbonylchloride (1) and alkyl (triphenylphosphoranylidene) acetates (2a–b). The synthesized compounds were characterized by elemental analysis, spectroscopic studies (3a–b), and single crystal X-ray diffraction (3a). The mechanism of the reaction between (1) and (2a) was studied by AM1, and the geometrical parameters of the studied molecules were also carried out in B3LYP methods with the standard 6–31G (d,p) basis set. NBO analysis were studied for 1 and 2a B3LYP methods with the standard 6–31G (d,p) basis set.     

Radioprotective and Antitumor Activity of Some Novel Amino Acids and Imidazoles Containing Thieno[2,3-d]pyrimidine Moiety

A variety of novel thieno[2,3-d]pyrimidine derivatives, comprising amino acids 3a–l, imidazothieno-pyrimidines 4A, 4b–h, and 7, were obtained via the reaction of 4-chloro-5,6-dimethylthieno[2,3-d]pyrimidine 1 with a variety of reagents. The structures of these compounds were confirmed by microanalysis, IR, ¹H NMR, and mass spectrometry. Some of the obtained compounds showed promising radioprotective and antitumor activities.     

Immobilization of laccase on polymer grafted polytetrafluoroethylene membranes for biosensor construction

In this study, Trametes versicolor laccase was immobilized on polytetrafluoroethylene (PTFE) membranes using two different techniques, entrapment to gelatin and covalent immobilization to the surface. For surface immobilization, functional groups were formed on PTFE surface by radiofrequency (RF) plasma treatment followed by polymer grafting. Two different polymers, polyacrylamide (pAAm) and polyacrylic acid (pAAc) were tried. For polyacrylamide grafted PTFE, a two-step polymerization process was used. The membranes were first treated with hydrogen plasma and pAAm grafted PTFE (pAAm-g-PTFE) was then formed by argon plasma treatment. To produce pAAc grafted PTFE (pAAc-g-PTFE), the surface was first treated with argon plasma and AAc was then attached to the surface by heat treatment (70 °C, 6 h). For both cases, an optimized carbodiimide coupling reaction was used for laccase immobilization. Enzyme activity was measured by an oxygen electrode using guaiacol as substrate. All three biosensing membranes were characterized and compared in terms of optimum working conditions, storage stability and reusability. Our study concluded that although a higher activity was obtained by gelatin entrapped laccase, its mechanical instability and poor storage life makes the gelatin biosensor unattractive for multiple usages and for field measurements. pAAc-g-PTFE biosensor was found to be more stable and highly reusable (ca. 50 times) when compared with the other two biosensors. In addition, its sensitivity was suitable for field applications. Therefore, the pAAc-g-PTFE biosensor could be proposed as an alternative on-site detection tool for phenolic compound monitoring.     

Determination of lead separated selectively with ion exchange method from solution onto BCW in Sirnak, East Anatolia of Turkey

There are approximately 82 million of tons asphaltites reserves in ?irnak, East Anatolia of Turkey. The present study was investigated to employ ashes of S?rnak BCW (burned coal waste) as an ion exchange in removal of important toxic metal, Lead (Pb), in high yields by adsorption. The ion exchange characteristics of lead onto BCW from aqueous solution were investigated with respect to the changes in pH of solution, adsorbent dosage, initial metal ion concentration, contact time and temperature of solution. For the adsorption of lead, the Langmuir isotherm model fitted to equilibrium data better than the Freundlich isotherm model. Thermodynamic functions, the change of free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) of adsorption were also calculated for lead. These parameters showed that the adsorption was feasible, spontaneous and exothermic at 293–333 K. Experimental data were also evaluated in terms of kinetic characteristics of adsorption. The batch kinetic data were correlated to the pseudo-first order and pseudo-second order models. The data fitted better to the pseudo-second order equation. The activation energy of systems was determined. Experimental data have shown that BCW that was used in unmodified form; as low cost, readily available ion exchange; can be used for removal of lead from industrial waste waters. Analysis was determined using Flame Atomic Absorption Spectrometry (FAAS).     

One-pot synthesis of gold nanoparticles using tetradentate porphyrins

In this study, the meso-tetra (p-hydroxyphenyl) porphyrin and meso-tetra (m-hydroxyphenyl) porphyrin were coated on to gold nanoparticles (AuNPs) via thioacetate anchors which easily dissociate to form S–Au bonds. 4-tert-butyl phenyl thioacetate-AuNPs were prepared and used as a monodentate passivant to control the size of the tetradentate porphyrin-AuNPs. The porphyrin-coated AuNPs were characterized by UV–Vis, TEM, XRD, and XPS analyses. The tetradentate porphyrin-AuNPs size is within a range of 5–15 nm in diameter with exotic shapes. The plausible network formation for AuNP@p-TPP-SAc and the capping structure of the AuNP@m-TPP-SAc have been suggested.     

Green preparation of Pd nanoparticles on SBA-15 via supercritical fluid deposition and application on Suzuki–Miyaura cross-coupling reaction

A well-dispersed green Pd/SBA-15 catalyst with an average size of 13.7 nm and 492.6 m²/g BET surface area is prepared via supercritical fluid deposition method with a new bipyridyl precursor that enables reduction at mild conditions at 80 °C and 17.2 MPa. The catalytic performance of Pd/SBA-15 prepared using scCO₂ with hydrogen reduction was assessed for Suzuki–Miyaura coupling reaction of bromobenzene and phenylboronic acid that was chosen as a model coupling reaction. The catalyst was tested in six different solutions and in three organic and inorganic bases during reactions. In general, the effect of bases is investigated when solvents are held constant and K₂CO₃ appears to have the best results in the activity studies used. For each of the 3 bases used, the highest catalytic activity was reached as the result of the solvent system being ethanol/water (1:1). The highest catalytic conversion was obtained in the ethanol-K₂CO₃ solvent-base pair. The catalyst synthesized in this study exhibited high activities and TON value was found as 160.8 at room temperature.     

A Review of Human Coronaviruses’ Receptors: The Host-Cell Targets for the Crown Bearing Viruses

A novel human coronavirus prompted considerable worry at the end of the year 2019. Now, it represents a significant global health and economic burden. The newly emerged coronavirus disease caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the primary reason for the COVID-19 global pandemic. According to recent global figures, COVID-19 has caused approximately 243.3 million illnesses and 4.9 million deaths. Several human cell receptors are involved in the virus identification of the host cells and entering them. Hence, understanding how the virus binds to host-cell receptors is crucial for developing antiviral treatments and vaccines. The current work aimed to determine the multiple host-cell receptors that bind with SARS-CoV-2 and other human coronaviruses for the purpose of cell entry. Extensive research is needed using neutralizing antibodies, natural chemicals, and therapeutic peptides to target those host-cell receptors in extremely susceptible individuals. More research is needed to map SARS-CoV-2 cell entry pathways in order to identify potential viral inhibitors.     

Synthesis of a hexafluoropropylidene-bis(phthalic anhydride)-based polyimide and its conducting polymer composites with polypyrrole

A new electrically conducting composite film from polypyrrole and 4,4′-(hexafluoroisopropylidene)-bis(phthalic anhydride)-based polyimide was prepared. Pyrrole and the dopant ion can easily penetrate through the polyimide substrate and electropolymerize on the platinum (Pt) electrode due to the swelling of the polyimide on the metal electrode. The electrochemical properties of polypyrrole-polyimide (PPy/PI) composite films have been investigated by using cyclic voltammetry. The PPy/PI composite film is suitable for use as the electroactive material owing to its stable and controllable electrochemical properties. The electrical conductivity of composites falls in the range 0.0035–15 S/cm. Scanning electron micrograph, FTIR, and thermal studies indicate that PPy and PI form a homogeneous material rather than a simple mixture. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3009–3016, 1997     

Histopathological Changes in Liver and Heart Tissue Associated with Experimental Ultraviolet Radiation A and B Exposure on Wistar Albino Rats

This study aims to evaluate the influences of ultraviolet radiation A and B ( UVA + B) exposure on the liver and heart organs of albino rats. Female Wistar Albino rats, whose hair of the dorsal skin was shaved, were exposed to a combined UVA + B radiation for 2 h/day, for 4 weeks in order to be compared with the control group. Histopathological findings in vital organs (liver and heart) were evaluated. Tissues were fixed in 10% buffered formalin (pH = 7.2) and embedded in paraffin. The histopathological findings were examined on the H&E stained sections with light microscopy. The results show that the liver and the heart were injured in the UVA + B group. Liver tissue in the UVA + B group showed minimal vacuolation, enlargement of hepatocytes and bile duct proliferation, and the heart tissue showed hibernomas; uniform large cells resembling brown fat with coarsely granular to multivacuolated cytoplasm that is eosinophilic or pale with a small central nucleus. The number of hibernoma cases was significantly higher in the UVA + B group compared with the control group (P = 0.021). The control group showed normal liver and heart histology with normal adipose tissue in the pericardium. As a result, UVA + B exposure has toxic effects, especially on the liver and the heart of Wistar albino rats. UV radiation may cause such adverse effects in humans. Therefore, protection against the harmful effects of UV radiation is of significant importance for skin and organs.