Symmetrical and unsymmetrical incorporation of active biological monomers on the surface of phosphorus dendrimers

Phosphorus-containing dendrimers are attractive carriers for the delivery of bioactive molecules due to their very particular architecture, globular shape and chemical and physical properties. Herein we report a simple synthetic approach of ethacrynic acid derivatives loaded-phosphorus dendrimers by symmetrical grafting of ethacrynic acid analogues by nucleophilic substitution of each chlorine of P(S)Cl₂ end groups. We report also for the first time an unsymmetrical grafting of two different phenol derivatives by a selective substitution of one chlorine of P(S)Cl₂ end group followed by the grafting of the second phenol.     

Determination of three antidepressants in urine using simultaneous derivatization and temperature‐assisted dispersive liquid–liquid microextraction followed by gas chromatography–flame ionization detection

This paper presents a fast and simple method for the extraction, preconcentration and determination of fluvoxamine, nortriptyline and maprotiline in urine using simultaneous derivatization and temperature‐assisted dispersive liquid–liquid microextraction (TA‐DLLME) followed by gas chromatography–flame ionization detection (GC‐FID). An appropriate mixture of dimethylformamide (disperser solvent), 1,1,2,2‐tetrachloroethane (extraction solvent) and acetic anhydride (derivatization agent) was rapidly injected into the heated sample. Then the solution was cooled to room temperature and cloudy solution formed was centrifuged. Finally a portion of the sedimented phase was injected into the GC‐FID. The effect of several factors affecting the performance of the method, including the selection of suitable extraction and disperser solvents and their volumes, volume of derivatization agent, temperature, salt addition, pH and centrifugation time and speed were investigated and optimized. Figures of merit of the proposed method, such as linearity (r² > 0.993), enrichment factors (820–1070), limits of detection (2–4 ng mL^?1) and quantification (8–12 ng mL^?1), and relative standard deviations (3–6%) for both intraday and interday precisions (concentration = 50 ng mL^?1) were satisfactory for determination of the selected antidepressants. Finally the method was successfully applied to determine the target pharmaceuticals in urine. Copyright © 2014 John Wiley & Sons, Ltd.     

Molecular dynamics and alignment studies of silica-filled 4-pentyl-4′-cyanobiphenyl (5CB) liquid crystal

A comprehensive study of the dielectric properties of 4-pentyl-4′-cyanobiphenyl (5CB) liquid crystal filled with silica particles (particle size 30–80 nm, concentration 2, 3, 5, 10 and 15 wt%). Dielectric spectroscopy in the frequency range 100 to 10 7 Hz was applied to investigate the influence of the filler on the dynamic behaviour of the liquid crystal molecules in both the nematic and isotropic phases. In this frequency range one relaxation process is observed (at f>10⁶ Hz). The dynamical behaviour of the 5CB liquid crystal is described by the Cole-Cole relaxation function. The temperature dependence of the relaxation time obeys the empirical Arrhenius equation. The activation energies are approximately 75 kJ mol¹ for the pure 5CB sample in the nematic phase and 50 kJ mol¹ for the 5 wt% silica-filled 5CB sample. These values are compared with the corresponding literature values. The reversible electro-mechanical response of these samples under the influence of an applied a.c. electric field is investigated.     

Flexural strength of silica fume,fly ash,and metakaolin of hardened cement paste after exposure to elevated temperatures

Journal of Thermal Analysis and Calorimetry - The mechanical properties of concrete based mainly on flexural and compressive bearing capacity. Generally, researchers have an interest in the...     

Evaluation of antibacterial and antioxidant activities of Artemisia campestris (Astraceae) and Ziziphus lotus (Rhamnacea)

The present work quantitatively evaluates the antimicrobial and antioxidant potentials of two Libyan folk medicinal plants [Artemisia campestris (Astraceae) and Ziziphus lotus (Rhamnacea)] that commonly grow in the south of Libya. The crude methanolic leaves extracts of both plants are appreciably active against Gram-positive species, associated with week anti-Gram-negative activity. These two plant extracts also showed reasonably high contents of polyphenolics and alkaloids, with minimal inhibitory concentrations between 12.5–25 and 250–1000 μg/ml for Gram-positive and Gram-negative species, respectively. Results collectively suggest that A. campestris and Z. lotus are not only reliable natural sources of antimicrobials but also potential sources of phenolic antioxidants and hence could be nominated for future intensive studies.     

Antioxidants and Bioactive Compounds in Licorice Root Extract Potentially Contribute to Improving Growth,Bulb Quality and Yield of Onion (Allium cepa)

The increasing culinary use of onion (Alium cepa) raises pressure on the current production rate, demanding sustainable approaches for increasing its productivity worldwide. Here, we aimed to investigate the beneficial effects of licorice (Glycyrrhiza glabra) root extract (LRE) in improving growth, yield, nutritional status, and antioxidant properties of two high-yielding onion cultivars, Shandaweel and Giza 20, growing under field conditions in two consecutive years. Our results revealed that pretreatments of both onion cultivars with LRE exhibited improved growth indices (plant height and number of leaves) and yield-related features (bulb length, bulb diameter, and bulb weight) in comparison with the corresponding LRE-devoid control plants. Pretreatments with LRE also improved the nutritional and antioxidant properties of bulbs of both cultivars, which was linked to improved mineral (e.g., K⁺ and Ca²⁺) acquisition, and heightened activities of enzymatic antioxidants (e.g., superoxide dismutase, catalase, ascorbate peroxidase, glutathione peroxidase, and glutathione S-transferase) and increased levels of non-enzymatic antioxidants (e.g., ascorbic acid, reduced glutathione, phenolics, and flavonoids). LRE also elevated the contents of proline, total free amino acids, total soluble carbohydrates, and water-soluble proteins in both onion bulbs. In general, both cultivars displayed positive responses to LRE pretreatments; however, the Shandaweel cultivar performed better than the Giza 20 cultivar in terms of yield and, to some extent, bulb quality. Collectively, our findings suggest that the application of LRE as biostimulant might be an effective strategy to enhance bulb quality and ultimately the productivity of onion cultivars under field conditions.     

The spectrum of a weighted Laplacian in the half‐space

J. Banasiak In this paper, we deal with spectral properties of a weighted Laplacian in the half‐space when a Dirichlet or a Neumann boundary condition is imposed. After proving that the spectrum is discrete under suitable assumptions, we give explicit formulae of eigenvalues and eigenfunctions in a specific case. In particular, the obtained eigenfunctions are rational or pseudo‐rational and have remarkable orthogonality properties. These results suggest the use of the discovered functions for approximating solutions of elliptic problems in the half‐space. Copyright © 2015 John Wiley & Sons, Ltd.     

Ligational,DFT modeling and biological properties of some new metal complexes with 3-(bromoacetyl)coumarin and 1,10-phenanthroline

The synthesis and characterization of Mn (II), Fe (II), Co (II), Ni (II), Cu (II) and Zn (II) complexes with 3-(bromoacetyl)coumarin (BAC) in presence of 1,10-phenanthroline (Phen) were reported and described by elemental analysis, molar conductivity, FT-IR, UV–Vis and effective magnetic moments. TG and DTG have been applied to study the decomposition mechanisms for BAC, Phen and their complexes. The analytical results and spectral studies showed that BAC and Phen act as bidentate ligands via oxygen of α, β-unsaturated ketone and oxygen of lactone carbonyl of coumarin and two pyridyl nitrogen atoms of Phen. Octahedral geometries have been proposed for all complexes and the kinetic parameter (E*, ΔH*, ΔS* and ΔG*) were calculated using Coats-Redfern (CR) and Horowitz-Metzeger (HM) methods. DFT calculations (bond lengths, bond angles, total energy, heat of formation, dipole moment and the lowest energy model structures) have been determined. The antibacterial activities for synthesized complexes were assayed against some selected bacterial and the complexes displayed a very highly significant against L. monocytogens.     

Transition metal complexes of nano bidentate organometallic Schiff base: Preparation,structure characterization,biological activity,DFT and molecular docking studies

An organometallic NO‐bidentate Schiff base, (2‐(1‐((1‐carboxyethyl)imino)ethyl) cyclopenta‐2,4‐dien‐1‐yl)(cyclopenta‐2,4‐dien‐1‐yl) iron (HL) was synthesized by condensation of 2‐acetylferrocene with amino acid alanine. Then its octahedral Cr (III), Mn (II), Fe (III), Co (II), Ni (II), Cu (II), Zn (II) and Cd (II) complexes were synthesized. All compounds were characterized on the basis of elemental analysis (C, H, N and M), molar conductivity, FT‐IR, UV–Vis, ¹H‐NMR, SEM, mass analysis and thermal studies. Furthermore, computational studies of HL ligand have been carried out by DFT/B3LYP method. HOMO and LUMO energy values, chemical hardness‐softness, electronegativity, electrophilic index and other parameters were calculated. SEM micrographs of HL ligand and its [Cd (HL)(H₂O)₂Cl₂].2H₂O complex, showed that they were prepared in nano‐structure forms with particle size 54 and 41 nm, respectively. Antifungal and antibacterial activities of HL ligand and its metal complexes have been screened in vitro against different species such as Aspergillus fumigatus, Candida albicans, Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Salmonella typhimurium. The synthesized compounds were evaluated for their anticancer activities against breast cancer cell line (MCF‐7) and normal melanocytes cell line (HFB‐4). It was found that [Co (HL)(H₂O)₂Cl₂].3H₂O complex had the lowest IC₅₀ value (10.9 μg/ml) and hence was the most active one. Finally, the optimized structures of the Schiff base and its Co (II) complex have been used to accomplish molecular docking studies with receptors of 3HB5, 3MIW, 5IBV and 4WM8 to determine the most preferred mode of interaction.