DNA interaction, antioxidant and in vitro cytotoxic activities of some mononuclear metal(II) complexes of a bishydrazone ligand

Publication date: 1 September 2017
Source:Materials Science and Engineering: C, Volume 78
Author(s): Chellaian Justin Dhanaraj, Jijo Johnson
A tridentate ONO donor bishydrazone ligand, 3-(((3-oxoindolin-2-ylidene)hydrazono) methyl)quinoxalin-2(1H)-one (L) was synthesized. Using the ligand, mononuclear metal complexes of the type [M(L)(OAc)] (M=Co(II), Ni(II), Cu(II) and Zn(II), OAc=–OCOCH3) were synthesized. The newly synthesized compounds were thoroughly characterized by various analytical and spectral techniques. Tetrahedral geometry was proposed for Co(II), Ni(II) and Zn(II) complexes, while square planar geometry has been assigned to the Cu(II) complex. The in vitro antibacterial, antifungal and antioxidant studies reveal that the Cu(II) complex of the bishydrazone ligand possess higher activities. DNA binding studies suggest that the present compounds interact with CT DNA through intercalation. This was further supported by molecular docking. Gel electrophoresis studies substantiated the involvement of free radicals in the cleavage of pUC18 DNA. In vitro cytotoxicity of the compounds against MCF-7 cell line was also examined. The molecular modeling studies reveal that the compounds strongly interact with VEGFR-2 kinase receptor through hydrogen bonding, π-π, π-cation and sigma-π interactions. The bioavailability and bioactivity determination of the compounds suggest that the present compounds may be utilized as drug candidates.

Graphical abstract

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Electronic structure and half-metallicity in new Heusler alloys CoYO2 (Y=Sc, Ti, V, Cr, Mn, Fe, Ni, Cu, and Zn)

Publication date: 15 September 2017
Source:Journal of Magnetism and Magnetic Materials, Volume 438
Author(s): S. Esteki, F. Ahmadian
First-principles calculations based on density functional theory (DFT) using the self-consistent full-potential linearized augmented plane wave (FPLAPW) method were applied to study the electronic structures and magnetic properties of new Heusler alloys CoYO2 (Y=Sc, Ti, V, Cr, Mn, Fe, Ni, Cu, and Zn). The calculated formation energies of these compounds were negative, therefore, they can be synthesized experimentally. All compounds were stable in ferromagnetic AlCu2Mn-type structure. In AlCu2Mn-type structure, CoScO2, CoFeO2, and CoNiO2 compounds were HM ferromagnets, CoCuO2 was a nearly half-metal, CoZnO2 was a spin gapless semiconductor, and other compounds were conventional ferromagnets. In CuHg2Ti-type structure, CoTiO2 compound had a nearly HM characteristic, CoVO2 was a spin gapless semiconductor, and other compounds were conventional ferromagnets. The origin of the half-metallic band gap for CoScO2 alloy Heusler alloy was well understood. The total magnetic moments of the three HM compounds obeyed Slater-Pauling rules (Mtot=22-Ztot and Mtot=32-Ztot). CoScO2 had the widest region of half-metallicity between the three half-metals indicating its high robustness of half-metallicity with respect to the variation of lattice constants.



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Screening of Passiflora L. mineral content using principal component analysis and Kohonen self-organizing maps

Publication date: 15 October 2017
Source:Food Chemistry, Volume 233
Author(s): Cleber Galvão Novaes, Ivana Lago da Silva Romão, Berlane Gomes Santos, Jéssica Palhares Ribeiro, Marcos Almeida Bezerra, Erik Galvão Paranhos da Silva
A method using digestion with diluted nitric acid and inductively coupled plasma optical emission spectrometry was applied to determine metal ions in the peel, pulp, and seed of Passiflora edulis f. flavicarpa and Passiflora cincinnata cultivated in the Bahia state, Brazil. Plasma parameters (radio frequency power and argon flow rates) were optimized. The quantification limits (µg g⁻¹) were: Ca (43.0); Co (1.3); Cu (10.0); Fe (10.0); K (20.0); Mg (26.6); Mn (0.33); Na (56.6) and Zn (10.0). The accuracy of the method was evaluated by the analysis of certified reference materials (NIST 1567a Wheat Flour and NIST 1577b Bovine Liver). Recovery studies were carried out and values found were between 89 and 120%. PCA and Kohonen self-organizing maps showed the formation of groups, corresponding to the fruit parts. Thus, passion fruit has great importance and biological potential, due to its high content of K and low Na.



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Enhancement of electric and magnetic properties by tuning Co cluster in ZnO films via high magnetic field

Publication date: 15 September 2017
Source:Applied Surface Science, Volume 416
Author(s): Yang Gao, Guojian Li, Zhao Wang, Shan Liu, Qiang Wang
To reveal the origin of magnetic coupling in dilute magnetic semiconductors (DMSs), this article utilized high magnetic field (HMF) in the process of oxidizing Co/Zn bilayers to study the influence of Co clusters and oxygen vacancy (Vo) content control on magnetic and electrical properties of Co doped ZnO (Co-ZnO) films. Results indicated that HMF can suppress the diffusion of Co and remain the content of Co clusters compared with oxidation growth in the absence of HMF. Moreover, HMF promoted the oxidation of Zn, improved the crystallinity in the films, and lowered the content of Vo. Consequently, the resistivity of the films oxidized in HMF was decreased by 50%, while both the saturation magnetization and coercivity were increased by 100%. This indicates that contribution of more Co clusters to the magnetic properties of the films is greater than that of Vo.



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Relationships between degree of milling and loss of Vitamin B, minerals, and change in amino acid composition of brown rice

Publication date: 1 September 2017
Source:LWT - Food Science and Technology, Volume 82
Author(s): Kun-lun Liu, Jia-bao Zheng, Fu-sheng Chen
The effects of the degree of milling (DOM) on amino acid composition, thiamine, riboflavin, phytic acid (PA), and mineral (Mg, Fe, Zn, Mn, Cu, Ca, Se, and Pb) contents of japonica Xinfeng 2 and indica T-You 15 brown rice were investigated. Almost all amino acids slightly decreased as DOM increased. Quadratic and linear relationships were observed between DOM and milling time at 0–30 s and 30–100 s, respectively. Thiamine and riboflavin content decreased linearly as DOM increased. Approximately 57.6–65.4% of thiamine and 40.3–45.7% of riboflavin were removed after 30 s of milling (DOM = ca. 9%). Considerable losses were observed for PA, Mg, Mn, Fe, and Pb during milling (DOM = ca. 9%), whereas the losses of Ca, Cu, Zn, and Se were relatively lower. In addition, the linear correlations of Mg, Mn, Pb, and Fe levels with PA concentration were revealed. These results indicate that DOM should be supervised to improve nutrient utilization and appropriately control toxic metal contamination.

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Enhanced dielectric permittivity and photoluminescence in Cr doped ZnS nanoparticles

Publication date: 15 September 2017
Source:Applied Surface Science, Volume 416
Author(s): Virpal, Jitender Kumar, R. Thangaraj, Sandeep Sharma, Ravi Chand Singh
The effect of Cr doping on dielectric and optical properties of ZnS nanoparticles was systematically investigated at room temperature. Structural analysis confirmed that dopant occupy the regular lattice and interstitial sites in host lattice. Experimental data revealed exceptionally large, low frequency dielectric constant (ϵ′≈10⁶) and enhanced photoluminescence emission in Cr doped ZnS nanoparticles. It is argued that larger value of the dielectric constant in doped nanoparticles originate due to combined effect of Maxwell–Wagner phenomenon and microscopic spontaneous polarization, when larger ionic radius Zn²⁺ (0.74Å) ions are replaced by smaller ionic radius Cr³⁺(0.63Å) ions. The huge enhancement in the value of dielectric constant and emission intensity justify the use of doped ZnS nanostructures for various technological applications.

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Highlights

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Improving the efficiency of quantum-dot-sensitized solar cells by optimizing the growth time of the CuS counter electrode

Publication date: 15 September 2017
Source:Applied Surface Science, Volume 416
Author(s): Chozhidakath Damodharan Sunesh, Chandu V.V.M. Gopi, Mohammed Panthakkal Abdul Muthalif, Hee-Je Kim, Youngson Choe
CuS counter electrodes (CEs) were prepared to fabricate efficient quantum-dot-sensitized solar cells (QDSSCs) based on a CdS/CdSe photo sensitizer. The CEs were prepared on a fluorine-doped tin oxide (FTO) glass substrate by a facile chemical bath deposition (CBD) method by dissolving CuSO4·5H2O and CH3CSNH2 in water, followed by adding 0.25mM polyvinylpyrrolidone (PVP). The CBD was performed at 60°C for 1h, 2h, and 3h, and the samples were labeled as CuS 1h, CuS 2h, and CuS 3h, respectively. The QDSSCs were assembled using prepared CuS CEs and a TiO2/CdS/CdSe/ZnS photoanode, and the effect of the growth time of CuS CEs on the QDSSC performance was investigated. As the CuS growth time increases, the short-circuit current density (Jsc), fill factor (FF), and open-circuit voltage (Voc) of the QDSSCs gradually increases, leading to an enhanced power conversion efficiency (η). QDSSCs that use the CuS 2h CE exhibit a high Jsc of 14.31mAcm⁻², Voc of 0.603V, and FF of 0.49, which are higher than that using conventional Pt electrodes as well as CuS 1h and CuS 3h electrodes. The electrochemical impedance spectroscopy results show that the CuS 2h CE exhibits an inferior charge transfer resistance of only 2.93Ω, which is 33 times lesser than that of the Pt CE. The enhanced device performance of CuS 2h is ascribed to the high catalytic activity and low charge transfer resistance of the CuS CE in the reduction process of oxidized polysulfide. Consequently, a superior power conversion efficiency of 4.27% is achieved for QDSSCs utilizing CuS 2h.

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