Hydrodistillation–Headspace Solvent Microextraction: An Efficient Method for Analysis of the Essential Oil from the Seeds of Foeniculum vulgare Mill.

Hydrodistillation–headspace solvent microextraction (HD–HSME) has been used for isolation and preconcentration of the essential oil from the seeds of Foeniculum vulgare Mill. The effect on extraction efficiency of different conditions, for example sample mass, extraction time, microdrop volume, and choice of solvent, was studied and all were optimized. The results were compared with those from hydrodistillation, as reference method. Fourteen compounds were identified; the main components were trans-anethole (70.4%), fenchone (9.3%), and p-allylanisole (8.8%). The results were in good agreement with those obtained by hydrodistillation.     

Synthesis,crystal structures and antibacterial studies of oxidovanadium(IV) complexes of salen-type Schiff base ligands derived from meso-1,2-diphenyl-1,2-ethylenediamine

A series of new derivatives and previously reported Schiff base ligands and their oxidovanadium(IV) complexes were synthesized, characterized and tested as potential antibacterial agents against four human pathogenic bacteria. These N₂O₂ type Schiff base ligands were derived from the condensation of meso-1,2-diphenyl-1,2-ethylenediamine with different salicylaldehyde derivatives, and their metal complexes were obtained from the reaction of these ligands with bis(acetylacetonato)oxidovanadium(IV). Our studies showed that the metal complexes had moderate antibacterial activity, and this activity was higher than that of the free ligands against both Gram-positive and Gram-negative bacteria. Besides, it was found that the presence of more substituents on the ligands increases the antibacterial activities of both the free ligands and their complexes. The crystal structures of H₂L⁴ and its corresponding complex VOL⁴ were determined by X-ray crystallography.     

Self‐Collimation in Photonic Crystals: Applications and Opportunities

A comprehensive review considering recent advances in self‐collimation and its applications in optical integration is covered in the current article. Self‐collimation is compared to the conventional technique of photonic bandgap engineering to control the light propagation in photonic crystal‐based structures. It is fully discussed how the self‐collimation phenomenon can be tailored to be independent of the incident angle and polarization. This adds substantial flexibility to the structure to overcome light coupling challenges and simultaneously aids in the omission of bulk and challenging elements, including polarizers and lenses from optical integrated circuits. Additionally, designed structures have the potential to be rescaled to operate in any desired frequency range thanks to the scalability rule in the field of electromagnetics. Moreover, it is shown that one can boost the coupling efficiency by applying an anti‐reflection property to the structure, which provides not only efficient index matching but also the matching between external waves with uniform amplitude and Bloch waves with periodic amplitude.     

Ionic Liquid Promoted Eco-friendly and Efficient Synthesis of 2,3-Dihydroquinazolin-4(1H)-ones

2,3-Dihydroquinazolin-4(1H)-ones were efficiently synthesised by the reaction of isatoic anhydride, a primary amine or ammonium acetate, and different aromatic aldehydes in 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF₄) without using any acidic catalyst. Also a bis-derivative of the title compound as a polyheterocyclic system was synthesised successfully in high yield.     

Observational constraints on FRW cosmologies with dark energy-dark matter interaction

In this paper, within the scope of FRW cosmology for $k=0, \pm 1$ , we investigate the dynamics of the universe in cosmological model where a scalar field nonminimally is coupled to matter field. By best-fitting the model parameters with the observational data, for the direct interaction between the dark sectors in the model, we obtain new constraints on cosmological parameters. The result with the best fitted model parameters supports the current universe acceleration in all models and shows that only in flat universe case the phantom crossing occurs twice in the past and once in the future. The best fitted reconstructed potential function and other physical functions are also obtained.     

The use of chitosan/Fe3O4 grafted graphene oxide for effective adsorption of rifampicin from water samples

Research on Chemical Intermediates - The environmental pollution caused by the introduction of antibiotics into the water resources poses serious threats to aquatic organisms and human...     

Hydrogen Production from Methane Decomposition Using a Mobile and Elongating Arc Plasma Reactor

Plasma Chemistry and Plasma Processing - Hydrogen and solid carbon were produced through methane decomposition in a plasma reactor with a parallel set of screw type helix and rod-like electrodes....     

Catalytic and antibacterial properties of 3-dentate carboxamide Pd/Pt complexes obtained via a benign route

The complexes Pd^II(qcq)(OAc) and Pt^II(qcq)Cl have been synthesized using environmentally benign synthesized ligands and characterized by elemental analyses: Fourier transform infrared spectroscopy, UV–visible spectroscopy, ¹H NMR spectroscopy, and X-ray diffraction. The catalytic activity of the complex was assessed, in different media, for the Mizoroki–Heck coupling reaction for typical aryl halides and terminal olefins under aerobic conditions. Since the base and the solvent were found to influence the efficiency of the reaction, reaction conditions, temperature, time, and the amount of K₃PO₄ and a mixture of H₂O/PEG, were optimized. We found, for the Mizoroki–Heck reaction coupling less reactive aryl chloride derivatives with olefins, promising activity for palladium catalysts. The electrochemical behavior of Hqcq and the Pd(II) complex was investigated by cyclic voltammetry and irreversible Pd^II/I reductions were observed. Hqcq and the Pd(II) and Pt(II) complexes were also screened for their in vitro antibacterial activity. They showed promising antibacterial activity comparable to that of the antibiotic penicillin.     

On the Average Number of Sylow Subgroups in Finite Groups

Czechoslovak Mathematical Journal - We prove that if the average number of Sylow subgroups of a finite group is less than $${{41} \over 5}$$ and not equal to $${{29} \over 4}$$ , then G is solvable...