Photocatalytic activity and radiation-attenuation ability of copper ions surface-doped dysprosium oxide

Journal of Materials Science: Materials in Electronics - Herein, Cu ions surface-doped Dy2O3 photocatalyst (Cu–Dy2O3) is synthesized utilizing hydrothermal technique to degrade methyl violet...     

Changes in membrane fatty acids and murein composition of Bacillus cereus and Salmonella Typhi induced by gamma irradiation treatment

This present study was carried out to evaluate the effects of gamma irradiation on the fatty acids (FA) and mureins composition of two different radiotolerant bacteria. Bacillus cereus LSPQ 2872 and Salmonella Typhi ATCC 19430 were used for this study. The bacterial strains were treated with a sublethal radiation dose of 1 kGy to cause a cellular damage. Gas chromatography (GC) and high performance liquid chromatography (HPLC) analysis were performed to demonstrate respectively the modification of the FA composition and the changes in muropeptide profile. Results obtained show, for both bacteria, that this treatment had a significant effect (P ≤ 0.05) on the FA content with an increase of unsaturated FA percentage. Substantial changes were also noticed for the relative percentage and the number of the muropeptides. This study represents one of the few to demonstrate the modifications on bacterial membrane as a cellular response to survive the ionising radiation stress.     

Influence of silver additions on electrical, mechanical and structures properties of rapidly solidified Sn–0.7%Cu alloy from melt

The eutectic alloy Sn_99.3-xCu_0.7Ag_x has been examined as one of the lead free solder alloys. Melting point, electrical resistivity, internal friction, elastic moduli, microhardness and the microstructure of the Sn_99.3Cu_0.7, Sn_95.8Cu_0.7Ag_3.5 and Sn_95.3Cu_0.7Ag₄ rapidly solidified lead free solder alloys have been investigated. The examined physical properties are improved by increasing silver contents in the studied lead free solder alloys. These improved properties indicate that these alloys are adequate for low temperature soldering applications.     

Three-Dimensional Network Polymeric Structure of (2-Amino-5 Ammoniopyridinium)[CuCl4]: Crystal Supramolecularity and Magnetic Properties

A single crystal structure determination of the complex (C₅H₉N₃)CuCl₄ [henceforth I] has been carried out. It crystallizes in the orthorhombic space group Cmca, with the cell parameters a=6.7053(5) Å, b=22.4171(19) Å, c=13.4173(9) Å, V=2016.8(3) Å³, and Z=8. In the complex, the anion is comprised of infinite zigzag chains of monochloro-bridged $\mathrm{CuCl}_{4}^{2-}$ units ?–CuCl₃–μ–Cl–CuCl₃–μ–Cl–CuCl₃–? surrounded by the pyridinium-ammonium cations. The Cu ions are five-coordinate to chloride ions in a distorted square-pyramidal geometry with the zigzag chains formed by corner-sharing polyhedra. The Cu ion is located 0.151 Å above the basal plane. In the crystal, there are four intermolecular hydrogen bonding interactions, linking the CuCl chains to the cations to form a 2D-network. The resulting 2D-networks are further linked by aryl?aryl (π?π) interactions within the cationic chains leading to a 3D-network. Variable temperature magnetic susceptibility data were fit to a one-dimensional S=1/2 antiferromagnetic chain model yielding C=0.44(1) emu-K/mol-Oe and J=?37(1) K.     

Plane Waves of a Fiber-Reinforcement Magneto-thermoelastic Comparison of Three Different Theories

In this article, the coupled theory, Lord–Shulman theory, and Green–Lindsay (GL) theory are used to study the influence of a magnetic field on a fiber-reinforced thermoelastic half-space. Normal mode analysis is used to solve a thermal shock problem. Numerical results for the temperature, displacement components, and stress components are given and illustrated graphically. A comparison is made between the coupled and GL theories in the absence and presence of a magnetic field and reinforcement.     

Isolation of powerful antioxidants from the medicinal halophyte Limoniastrum guyonianum

The antioxidant capacities of the crude extract, aqueous and ethyl acetate partitions of Limoniastrum guyonianum Boiss. (Zita) were investigated in this study. The ethyl acetate phase exhibited a significant antioxidant activity as judged by total antioxidant activity, DPPH test and reducing power. Fractionation of this extract by centrifugal partition chromatography (CPC) using quaternary Arizona solvent systems composed of n-heptane/ethyl acetate/methanol/water led to ten fractions. The antioxidant capacities of these fractions were assessed using the same previous tests. Fraction 8 showed the highest antioxidant capacity (1291.1mg GAE/g DR), the power ability to quench DPPH radical (IC(50)=2μg/ml) and to reduce Fe(3+) (EC(50)=65μg/ml). From this fraction, three powerful flavonoids were isolated (1-3): gallocatechin (1), epigallocatechin (2) and epigallocatechin-3-O-gallate (3). These findings suggest that the antioxidative property of L. guynianum is may be related to the presence of these flavonoids, which can be used in various industrial fields.     

Production and properties of chlorogenic acid lipophilic esters

Chlorogenic acid is a dietary polyphenol with important bioactivities. However, its high hydrophilicity prevents its applications as an antioxidant for lipid protection in a complex matrix such as food. Grafting an aliphatic chain onto chlorogenic acid, so‐called lipophilisation, via lipase‐catalysed esterification represents an efficient means of increasing its lipophilicity. A series of alkyl esters with various chain lengths were produced and used to explore the structure‐antioxidant activity relationship of amphiphilic antioxidants. Data obtained from complex systems (oil‐in‐water emulsion and cell culture) concluded that short or medium chain lengths enhance the antioxidant activity while longer chains tend to decrease the antioxidant ability of chlorogenic acid. This phenomenon remains to be fully explained. Acyl esters, in which the carboxylic acid group remains free were also produced and were shown to be interesting antioxidant candidates as well as useful tools for the understanding of antioxidant activities.     

A triple spin-labeling strategy coupled with DEER analysis to detect DNA modifications and enzymatic repair

In a spin: Spin-labeled oligonucleotides produced by click chemistry can be studied by EPR, by using a DEER sequence. This was used to test a complex triple-labeling strategy with damaged DNA. Extensive and accurate analysis of DNA structure and enzymatic repair processes were performed after digestion by EndoIV. Modified DNA structures and DNA-protein interactions can now be readily studied.