In the paper, the Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Photoelectron Spectroscopy (XPS) results of the surface layer formed on pure titanium after plasma electrolytic oxidation (micro arc oxidation) at the voltage of 450 V are shown. As an electrolyte, the mixture of copper nitrate Cu(NO3)2 (10–600 g/L) in concentrated phosphoric acid H3PO4 (98 g/mol) was used. The thickness of the obtained porous surface layer equals about 10 μm, and it consists mainly of titanium phosphates and oxygen with embedded copper ions as a bactericidal agent. The maximum percent of copper in the PEO surface layer was equal to 12.2 ± 0.7 wt % (7.6 ± 0.5 at %), which is the best result that the authors obtained. The top surface layer of all obtained plasma electrolytic oxidation (PEO) coatings consisted most likely mainly of Ti3(PO4)4∙nH3PO4 and Cu3(PO4)2∙nH3PO4 with a small addition of CuP2, CuO and Cu2O.

In the paper, the surface layers formed on nickel-titanium alloy during Plasma Electrolytic Oxidation (PEO), known also as Micro Arc Oxidation (MAO), are described. The mixture of phosphoric acid and copper nitrate as the electrolyte for all plasma electrochemical processes was used. Nitinol biomaterial was used for the studies. All the experiments were performed under the voltage of 450 V and current density of 0.3 A/dm 2 . The main purpose of the studies was to achieve the highest amount of copper in the surface layer versus amount of the copper nitrate in phosphoric acid. The highest copper concentration was found in the surface layer after the PEO treatment in the electrolyte consisting of 150g Cu(NO 3 ) 2 in 0.5 dm 3 H 3 PO 4 . The worst results, in case of the amount of copper in the NiTi surface layer, were recorded after oxidizing in the solution with 5 g Cu(NO 3 ) 2 .

Analysis of the spectral properties and structural differences of two turn-on ratiometric fluorescent receptors for Zn(2+) and Cd(2+) ions, derivatives of pyrrolo[2,3-b]quinoxaline (2), and earlier published 3 (Ostrowska et al. CrystEngComm 2015, 17, 498-502) was performed. Both ligands are E/Z push-pull olefins interconverting at room temperature, with barriers to rotation about enamine double bonds, from E to Z isomers of 19.3 ± 0.1 and 16.9 ± 0.3 kcal/mol and from Z to E of 16.9 ± 0.3 and 15.7 ± 0.2 kcal/mol, respectively. Diastereoisomers (E)-2 and (Z)-2 were isolated and characterized by X-ray structural analysis. The formation of complexes by (E/Z)-2 with acetates and acetylacetonates of Zn(2+) and Cd(2+) was monitored by UV-vis, fluorescence, and (1)H NMR titrations in acetonitrile, respectively. X-ray structural analysis for isolated [(E)-2]2Zn in relation to earlier published (E)-3-ZnOAc revealed the formation of a six-coordinated zinc ion with six- and four-membered bis-chelate rings by (E)-2. The chelate effect increases the ligand affinity for Zn(2+) (log β12 = 12.45) and causes the elongation of nitrogen-metal bonds. Extension of the coordination cavity size allows coordination of a cadmium ion. The introduction of a flexible ethylene linker between the fluorophore and ionophore pyridyl groups in 3 significantly affects the selectivity of zinc-ion recognition. The distorted tetrahedral geometry of (E)-3-ZnOAc with a four-coordinated zinc ion appears to be the most preferred because of the short donor-zinc distance with a 1:1 binding mode. The formation of the small coordination cavity size with six-membered bis-chelate rings provides an effective overlap of zinc and donor orbitals, precluding the coordination of a cadmium ion in the same manner as zinc.

First published on the web Xth XXXXXXXXX 200X DOI:Among three novel DBTAA derivatives only DBTAA-propyl-adenine conjugate 1 showed recognition of the consecutive oligo dT sequence by increased affinity and specific induced chirooptical response in comparison to other single stranded RNA and DNA; whereby of particular 10 importance is up until now unique efficient differentiation between dT and rU. At variance, its close analogue DBTAA-hexyl-adenine 2 did not reveal any selectivity among ss-DNA/RNA pointing out to the important role of steric factors (linker length); moreover non-selectivity of the reference compound (3, lacking adenine) stressed the importance of adenine interactions in the 1 selectivity. 15 IntroductionBoth, DNA and RNA exhibit a wide range of structural topologies, among which different single stranded (ss-) sequences are quite numerous. While ss-sequences are ubiquitous part of the RNA folding landscape, there are fewer 20 observations of stable ss-DNA cases, such as hairpins 1 or abasic sites, 2 to name some of them. Since ds-DNA is protected from reaction with a number of chemical and biological nucleases, 3 many studies have been aimed at exploiting the vulnerable ss-DNA. A number of small 25 molecules were synthesized that bind specifically at abasic lesions with an idea to inhibit the DNA repair system and in that way pronounce the action of antitumor drugs. 4 Moreover, recently many research groups have explored the potential of the DNA as a template for arraying multichromophoric 30 systems, among which non-covalent ss-DNA-associated dyes attracted considerable attention. 5 Until now, aryl-nucleobase conjugates efficiently recognized complementary nucleobases by affinity increase, 4 Zn-cyclene derivatives showed highly selective interactions 35 with uracil and thymine caused by specific coordination of Zn with two keto-groups. 6 Very recently, abasic sites and single base bulges in DNA were efficiently recognized by metalloinsertors, 7 or small-ligand-immobilized biosensor was applied for detecting thymine-related single-nucleotide 40 polymorphisms (SNPs). 8 However, longer oligo-dT sequences were not specifically recognised until now, especially in respect to closely related uracil analogues. Within the last decade we showed that small modifications in structure of aryl-nucleobase conjugates can control their selectivity toward 45 various ss-and ds-polynucleotide sequences. 9 On the other hand, for the dibenzotetraaza [14]annulene (DBTAA) derivatives we recently showed that the interactions of side-chains can finely tune selectivity toward various DNA/RNA and consequently control their biological 50 activity. 10a Specific properties of the DBTAA moiety, such as larger aromatic surface than the most of until now used arylmoieties and pronounced out-of-plane flexibility, offered intriguing possibilities in design of novel aryl-nucleobase conjugates. The very last generation of DBTAA derivatives 55 showed high (sub-micromolar) DNA/RNA affinity and selectivity toward dA-d...

In the paper, the glow discharge optical emission spectroscopy, X‐ray photoelectron spectroscopy, scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy results of a commercial purity titanium grade 2 after plasma electrolytic oxidation (PEO), also known as micro arc oxidation (MAO), are presented. The PEO treatment was performed in the electrolyte containing concentrated (85%) phosphoric acid with copper nitrate at the voltage of 450 ± 10 V for 1 min. For the electrolyte, copper nitrate addition from 300 to 600 g/l was used. Porous coatings of specific properties were obtained. The measurements results allow to state that the copper and nitrogen ions can be introduced into the surface layer formed on pure titanium by the plasma electrolytic oxidation. The distributions of these elements were detected to depend on the electrolyte composition, with the highest amounts revealed in the coating created in the electrolyte containing 600 g Cu(NO3)2 in 1 l H3PO4. Three sub‐layers of the coating, displayed in this work by two models, were developed in the study. The analysis performed shows that under the PEO treatment in each of the electrolytes used, the formation of coating with the top sub‐layers always enriched in copper compounds was found. Copyright © 2016 John Wiley & Sons, Ltd.