UV light induced surface modification of HDPE films with bioactive compounds

The development of different techniques for surface modification of polymers becomes popular in a last decade. These techniques preserve useful bulk polymer properties unchanged, while the activation of the polymer surface offers more possibilities for polymer applications.In this work, a new, one-step method for bio-activation of HDPE (high density polyethylene) surface by UV irradiation is presented. HDPE films coupled with selected active compound and a photoinitiator was treated by UV lamp, emitting light at 254 nm.For surface functionalization of HDPE films, the following compounds were employed: 2-aminopyridine (AP), N¹-(2-pyridylaminomethyl)-1,2,4-triazole (TA) and benzocaine (BC). The influence of irradiation time on the extent of surface changes was investigated. The modified polymer surfaces were investigated by Fourier transformed infrared (FTIR) and Raman spectroscopy, scanning electron microscopy (SEM) and contact angle measurements, demonstrating successful functionalization of HDPE surface.     

Microwave assisted synthesis of enantiomerically pure allylboronates

Stable allylboronates with a stereogenic centre α to the boronic ester moiety represent versatile reagents for stereoselective synthesis of homoallylic alcohols. Use of microwave irradiation in desilylation and sigmatropic rearrangement reactions allows rapid synthesis of α-chiral allylboronates utilized in the highly diastereo- and enantioselective synthesis of (Z)-configured homoallylic α-hydroxy esters by allyl additions to ethyl glyoxylate.     

Stereospecific ligands and their complexes. IV: Synthesis,characterization and cytotoxicity of novel platinum(IV) complexes with ethylenediamine-N,N′-di-S,S-2-propanoate and halogenido ligands: Crystal structure of s-cis-[Pt(S,S-eddp)Cl2]·4H2O and uns-cis-[Pt(S,S-eddp)Br2]

The syntheses of two novel platinum(IV) complexes of formula [PtX₂(S,S-eddp)]·nH₂O (S,S-eddp = ethylenediamine-N,N′-di-S,S-2-propanoate ion, X = chlorido (1) or bromido (2), n = 4, 0) are reported. The complexes have been obtained by direct reaction of corresponding potassium hexahalogenidoplatinate(IV) with neutralized ethylenediamine-N,N′-di-S,S-2-propanoic acid (H₂-S,S-eddp). The complexes were characterized by elemental analysis, infrared, ¹H and ¹³C NMR spectroscopy. The spectroscopically predicted geometrical configurations of the obtained complexes were confirmed by X-ray analyses of the crystal structures of the s-cis-[Pt(S,S-eddp)Cl₂]·4H₂O and uns-cis-[Pt(S,S-eddp)Br₂]. These complexes displayed significantly lower in vitro cytotoxicity in comparison to cisplatin.     

Au-Ag hybrid nanoparticle patterns of tunable size and density on glass and polymeric supports

This paper describes a method to pattern surfaces with Au-Ag hybrid nanoparticles. We used block copolymer micelle lithography of Au nanoparticles and electroless deposition of Ag. The combination of these two methods enables independent tuning of nanoparticle spacing and Ag-shell size. For this purpose, 8 nm large patterned Au nanoparticle seeds served as nuclei for the electroless deposition of silver that is based on a modified Tollens process with glucose. By adjusting the reaction conditions, specific growth of Ag on top of the Au seeds has been accomplished and analyzed by SEM, HRTEM, XEDS, and UV-vis spectroscopy. We could show that this versatile and green method is feasible on glass as well as on biomedical-relevant polymers like poly(ethylene glycol) hydrogels and amorphous Teflon. In conclusion, this method provides a new route to pattern glass and polymeric surfaces with Au-Ag hybrid nanoparticles. It will have many uses in applications such as surface enhanced Raman spectroscopy (SERS) or antimicrobial coatings for which hybrid nanoparticle density, size, and morphology are important.     

X-ray structural analysis, antioxidant and cytotoxic activity of newly synthesized salicylic acid derivatives

New salicylic (2-hydroxybenzoic) acid derivatives 1–6 were prepared by conventional heating or microwave irradiation of a mixture consisting of methyl salicylate and the corresponding amino alcohol (2,2′-dihydroxydiethylamine, 2,2′,2″-trihydroxytriethylamine or N-phenyl-2,2′-dihydroxydiethylamine) and metallic sodium as catalyst. For compounds 1, 3, and 5 X-ray structure analysis was performed, as well as molecular mechanics calculations (MMC), to define their conformation in terms of their energy minima. Comparison of crystal and MMC structures for these three compounds (1, 3, and 5) revealed that the intramolecular hydrogen bonds play an important role, stabilizing conformation of the most part of the molecule. The antioxidant activity and cytotoxicity of the synthesized derivatives were evaluated in a series of in vitro tests. The newly synthesized compounds exhibited strong activity against hydroxyl radical, as well as promising lipid peroxidation inhibition. The study showed that the electronic effects of the groups at the N atom are responsible for neutralization of the OH radical, i.e., antioxidant activity. Compounds 1–3 exhibited sub-micromolar cytotoxicity against HeLa S3, whereas compounds 1, 3 and 5 efficiently inhibited the growth of PC3 cells.     

Synthesis, structure and solvatochromic properties of some novel 5-arylazo-6-hydoxy-4-phenyl-3-cyano-2-pyridone dyes

ABSTRACT: BACKGROUND: A series of some novel arylazo pyridone dyes was synthesized from the corresponding diazonium salt and 6-hydroxy-4-phenyl-3-cyano-2-pyridone using classical reaction for the synthesis of the azo compounds. RESULTS: The structure of the dyes was confirmed by UV-vis, FT-IR, 1H NMR, 13C NMR spectroscopic technique and elemental analysis. The solvatochromic behaviour of the dyes was evaluated with respect to visible absorption properties in various solvents. CONCLUSIONS: The azo-hydrazone tautomeric equilibration is found to depend upon substituents as well as on solvents. The geometry data of the investigated dyes were obtained using DFT quantum-chemical calculations. The obtained calculational results are in very good agreement with the experimental data.     

New version of the integrated method for measuring small effects in experiments on beams extracted from a nuclear reactor at the effect sign switching frequency above the fundamental frequencies of the reactor power fluctuation spectrum

The principles of construction and the results of testing of a system for measuring P-odd asymmetries in nuclear reactions with polarized cold neutrons by the integrated method of recording events at the neutron polarization switching frequency above the fundamental frequencies of the reactor power fluctuation spectrum are presented. It is shown experimentally that if the signal under investigation is characterized by the spectral density of power decreasing with increasing frequency, switching of the equipment at a higher frequency decreases the measuring error. The dependence of the error of measurements of P-odd asymmetry in the emission of γ quanta in the ¹⁰B(n, α)⁷Li* ⟹ γ ⟹ ⁷Li(g.s.) reaction on the neutron polarization switching frequency is derived. The system described here is implemented experimentally for the first time.     

Protein stability in an ionic liquid milieu: on the use of differential scanning fluorimetry

Protein stability is a major bottleneck in the biotechnological application of ionic liquid-containing solvents, either in the frame of biocatalysis or protein storage. Herein, differential scanning fluorimetry was successfully implemented as a high throughput method to fast scan the impact of a number of cholinium-based ionic liquids on the stability of proteins.     

Topologies of some new sequence spaces, their duals, and the graphical representations of neighborhoods

Many interesting topologies arise in the theory of FK spaces. Here we present some new results on the topologies of certain FK spaces and the determinations of their dual spaces. We also apply our software package for visualization and animations in mathematics and its extensions to the representation of neighborhoods in various topologies.