Synthesis, characterization and antitumour studies on N-salicyl-N′-thiobenzohydrazide and its copper(II) complex

Summary The new potential tetradentate ligand N-salicyl-N-thiobenzohydrazide (H₂SBTH) and its Cu complex, [Cu(SBTH)], have been prepared and characterized by physico-chemical studies. In vivo antitumour activity of [Cu(SBTH)] has been tested against breast tumour in C₃H/J strain mice; LD ₅₀ values were also calculated. The cytotoxicity and antitumour effect of [Cu(SBTH)] is a maximum at 100 mg kg^-1 body weight injected intraperitoneally in mice carrying breast tumour. In vitro results of the ligand and the complex on P-815 (murine mastocytoma) and K-562 (human erythroleukemia cells) indicate that these compounds show significant inhibition on ³H-thymidine and ³H-uridine incorporation in DNA and RNA in these tumour cells. Light microscopic study of the treated tumour mass demonstrated that certain cellular degradation, such as disappearance of mitotic figures, loss in cellular compactness, distortion of nucleus and disruption of cytoplasmic boundaries, take place in complex-treated mice with tumours.     

Synthesis,evaluation and docking studies of some 4-thiazolone derivatives as effective lipoxygenase inhibitors

Some promising 4-thiazolone derivatives as lipoxygenase inhibitors were designed, synthesized, characterized and evaluated for anti-inflammatory activity and respective ulcerogenic liabilities. Compounds (1b, 1e, 3b, and 3e) exhibited considerable in vivo anti-inflammatory activity (57.61, 79.35, 75.00, and 79.35%) against carrageenan-induced rat paw edema model, whereas compounds (1e, 3b, and 3e) were found active against the arachidonic acid-induced paw edema model (55.38, 55.38, and 58.46%). The most potent compound (3e) exhibited lesser ulcerogenic liability compared to the standard diclofenac and zileuton. Further, the promising compounds (1e and 3e) were evaluated for in vitro lipoxygenase (LOX; IC₅₀?=?12.98 µM and IC₅₀?=?12.67 µM) and cyclooxygenase (COX) inhibition assay (COX-1; IC₅₀?>?50 µM and, COX-2; IC₅₀?>?50 µM). The enzyme kinetics of compound 3e was evaluated against LOX enzyme and supported by in silico molecular docking and molecular dynamics simulations studies. Overall, the results substantiated that 5-benzylidene-2-phenyl-4-thiazolones are promising pharmacophore for anti-inflammatory activity.     

Untersuchungen zum elektrochemischen Verhalten des Indiums an der Quecksilbertropfelektrode in Gegenwart einiger Monocarbonsäuren

Zusammenfassung An der Quecksilber-Tropfenelektrode zeigt In³⁺ bei Gegenwart von Glykolsäure, Brenztraubensäure, Buttersäure oder Lävulinsäure das für quasireversible Elektrodenprozesse typische Verhalten.

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Studies of the electrochemical behaviour of indium at the dropping-mercury electrode in the presence of some monocarboxylic acids

In the presence of glycolic, pyruvic, butyric or laevulinic acid In³⁺ at the dropping-mercury electrode behaves in a manner typical of quasi-reversible electrode processes.

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Design of Peptides with α,β-Dehydro-Residues: Syntheses and Crystal Structures of (i) N-Tertiarybutyloxycarbonyl-L-Ala-ΔPhe-L-Ala-OCH3 and (ii) N-Tertiarybutyloxycarbonyl-L-Leu-ΔPhe-L-Leu-OCH3

In order to contribute to design rules with α,β-dehydro amino acid residues, two peptides (i) Boc-Ala-ΔPhe-Ala-OCH₃ and (ii) Boc-Leu-ΔPhe-Leu-OCH₃ were synthesized and their crystal structures were determined. Peptide (i) with Ala residues on both sides of ΔPhe adopted a type II β-turn conformation with dihedral angles of two corner residues, φ₁ = ?62.6(4)^°, ψ₁ = 138.9(5)^°, φ₂ = 76.3(4)^° and ψ₂ = 13.1(3)^°, while the peptide (ii) with Leu residues formed an unfolded conformation with dihedral angles, φ₁ = ?81.9(5)^°, ψ₁ = ?28.3(4)^°, φ₂ = 56.7(5)^° and ψ₂ = 42.6(4)^°. The structure of peptide (i) was stabilized by an intramolecular 4→1 hydrogen bond between Ala³ NH and BOC carbonyl oxygen atom, whereas that of peptide (ii) was stabilized by van der Waals forces involving the side chains of two Leu residues.     

A novel synthesis of 4-propyl-2H-1-benzopyran-2-ones

Reaction of 2-hydroxybutyrophenones1–5 with ethoxycarbonylmethylenetriphenylphosphorane furnishes the 4-propyl-2H-1-benzopyran-2-ones6–10.

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Eine neue Synthese von 4-Propyl-2H-1-benzopyran-2-onen

Zusammenfassung Die Reaktion von 2-Hydroxybutyrophenonen1–5 ergab mit Ethoxycarbonylmethylentriphenylphosphoran die 4-Propyl-2H-1-benzopyran-2-one6–10

     

Interlaminar Fracture Toughness Characterization of Laminated Composites: A Review

Abstract

Interlaminar fracture toughness had been the subject of great interest for several years and is still interesting to the research community. In this article, a comprehensive analysis of fracture toughness in FRP laminates is presented. Primarily, toughness studies are undertaken on glass and carbon fiber reinforced composites under mode-I and mode-II loading conditions. The fracture behavior and its failure pattern depend on a number of parameters: fiber sizing/coating, matrix modification, insert film, fiber volume fraction, stacking sequence, specimen geometry, loading rate and temperature change. In fact, a state-of-the-art process enables increasing fracture resistance with “matrix toughening by carbon nanotubes (CNT) inclusion”. It enables production of materials having ultra-high strength and low weight. The present study has highlighted the available techniques of CNT incorporation: mechanical mixing, grafting and interleaving. Other aspects, such as the dispersion level, matrix viscosity, fiber surface roughness, loading weight %, bonding strength with epoxy, height and density of grown CNT, energy absorption mechanism during delamination, etc., have been examined as well. Although a clear correlation of all these parameters with fracture toughness is hard to establish, there is growing understanding of the surface-grown CNTs and interleaving processes as they ensure significant increase in fracture toughness.     

A novel calix[4]arene-based neutral semicarbazone receptor for anion recognition

A series of novel calix[4]arene-based neutral semicarbazone and thiosemicarbazone receptors have been synthesized and characterized. The molecular receptor 4a recognizes in preference to other anions (Cl⁻, Br⁻, I⁻, , and ) through a 1:1 binding-stoichiometry.     

Surface functionalization of quantum dots for biological applications

Quantum dots are a group of inorganic nanomaterials exhibiting exceptional optical and electronic properties which impart distinct advantages over traditional fluorescent organic dyes in terms of tunable broad excitation and narrow emission spectra, signal brightness, high quantum yield and photo-stability. Aqueous solubility and surface functionalization are the most common problems for QDs employed in biological research. This review addresses the recent research progress made to improve aqueous solubility, functionalization of biomolecules to QD surface and the poorly understood chemistry involved in the steps of bio-functionalization of such nanoparticles.     

Nanocrystalline properties of chemically deposited (Cd0.95‐Pb0.05)S:CdCl2, Gd/Dy films

Results of SEM and XRD studies, optical absorption spectra and photoluminescence emission spectra are presented for the films of (Cd_0.95‐Pb_0.05)S:CdCl₂, Gd/Dy prepared by chemical bath deposition technique and using thiophenol and methanol as capping agents. The deposition of films is based on precipitation followed by condensation on the substrates. SEM studies show existence of irregular distribution of particles alongwith presence of rod/tube type structure. The XRD studies show diffraction lines of CdS, PbS and CdCl₂. Blue shift has been observed in absorption spectra showing quantum confinement. Particle sizes determined from XRD studies and absorption spectral studies are found to lie in the nano range. Photoluminescence emission spectra consist of emissions in blue and green‐yellow regions. The observed emissions are related to the combination of defect levels and levels due to rare earths. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Asymptotic solution of a non-linear wave motion in an electron plasma

The theory of high-frequency waves has been used to calculate first and second-order asymptotic solutions for the propagation of non-linear waves in a cylindrical symmetric flow of an electron plasma. The behaviour of acceleration waves and weak shock waves has been analysed through these solutions and Whitham's rule for a weak shock wave on any wavelet has been confirmed through the first-order solution. The appearance of a weak shock wave on any wavelet has been determined and its strength, the location, and the speed of propagation have been found from the asymptotic solution presented in this paper. © 1997 by B. G. Teubner Stuttgart–John Wiley & Sons Ltd.