DNA binding, cleavage, and cytotoxicity of binuclear phenolate nickel(II) complexes

<p>Three binuclear phenolate complexes, [Ni₂(L¹)₂(OAc)](BPh₄)·DMF (<b>1</b>), [Ni₂(L²)₂(OAc)](BPh₄) (<b>2</b>), and [Ni₂(L³)₂(OAc)](OH)·3H₂O (<b>3</b>), where L¹ = 2-{[bis-(2-hydroxy-ethyl)-amino]-methyl}-4-methyl-phenol, L² = 2-{[bis-(2-hydroxy-ethyl)-amino]-methyl}-4-methoxy-phenol, and L³ = 2-{[bis-(2-hydroxy-ethyl)-amino]-methyl}-4-tert-butyl-phenol), have been synthesized. Single-crystal diffraction reveals that all the metal atoms are in a distorted octahedral geometry. The interactions of the complexes with calf thymus DNA (CT-DNA) have been investigated by UV–vis absorption, fluorescence emission, and circular dichroism spectroscopy and viscosity measurements. Furthermore, DNA cleavage mechanism shows that the complexes may be capable to promote DNA cleavage through oxidative DNA damage pathway, which is indicative of the involvement of hydroxyl radical, singlet oxygen, or singlet oxygen-like entity in the cleavage process. Cytotoxicity studies on the Hela and MCF-7 cancer cell lines show that complexes <b>1–3</b> exhibit excellent activity toward the tested tumor cell lines with respect to the standard drug carboplatin, revealing that they have the potential to act as effective metal-based anticancer drugs.</p

Interface Engineering of Graphene/CH₃NH₃PbI₃ Heterostructure for Novel p–i–n Structural Perovskites Solar Cells

Functionalized graphene is widely used in various functional devices. Here, we introduce a simple plane capacity model and the density functional theory to investigate the origin of charge transfer in the graphene/CH₃NH₃PbI₃ interface, where graphene can be p-type or n-type doped by combining with different exposed surfaces of CH₃NH₃PbI₃. Our calculations indicate that at the equilibrium distance, the work function of isolated graphene layer should be corrected by adding a value for assessing the charge transfer. After integrating the perovskite film with the functionalized graphene layer, we obtain a van der Waals heterostructure solar cell with a p–i–n configuration, which introduces a built-in electrical field to facilitate the separation and transport of the photogenerated carriers. The new p–i–n junction highlights the interface effect on graphene in solar cell, which offers an avenue to design new photovoltaic devices with high performance

Additional file 2: of A practical community-based response strategy to interrupt Ebola transmission in sierra Leone, 2014–2015

Technical supplementary for practical community-based response strategy to interrupt Ebola transmission in Sierra Leone, 2014-2015. (DOC 721 kb

Additional file 1: of A practical community-based response strategy to interrupt Ebola transmission in sierra Leone, 2014–2015

Multilingual abstracts in the six official working languages of the United Nations. (PDF 299 kb

Search for gamma-ray spectral lines with the DArk Matter Particle Explorer

The DArk Matter Particle Explorer (DAMPE) is well suitable for searching for monochromatic and sharp γ-ray structures in the GeV–TeV range thanks to its unprecedented high energy resolution. In this work, we search for γ-ray line structures using five years of DAMPE data. To improve the sensitivity, we develop two types of dedicated data sets (including the BgoOnly data which is the first time to be used in the data analysis for the calorimeter-based gamma-ray observatories) and adopt the signal-to-noise ratio optimized regions of interest (ROIs) for different DM density profiles. No line signals or candidates are found between 10 and 300 GeV in the Galaxy. The constraints on the velocity-averaged cross section for χχ→γγ and the decay lifetime for χ→γν, both at 95% confidence level, have been calculated and the systematic uncertainties have been taken into account. Comparing to the previous Fermi-LAT results, though DAMPE has an acceptance smaller by a factor of ∼10, similar constraints on the DM parameters are achieved and below 100 GeV the lower limits on the decay lifetime are even stronger by a factor of a few. Our results demonstrate the potential of high-energy-resolution observations on dark matter detection