Thermal,morphological, and mechanical properties of ethyl vanillin immobilized in polyvinyl alcohol by electrospinning process

In this study, polyvinyl alcohol (PVA) nanofibers with ethyl vanillin as an active compound were prepared using electrospinning technique. The final products of electrospinning process were in the form of nanofibers films. PVA/ethyl vanillin nanofibers, having fibers diameters in the range 100–1700 nm, were successfully electrospun from ethanol/water mixture of PVA and ethyl vanillin. The effects of immobilization process on ethyl vanillin thermal properties were investigated by differential scanning calorimetry (DSC). The results of DSC showed significant influence of immobilization process on thermal properties of ethyl vanillin. It was noticed that melting point of immobilized ethyl vanillin was lower (~55 °C) compared to free flavor (~77 °C). Our results showed that films based on PVA/ethyl vanillin nanofibers are mechanically stable.     

In Vitro Evaluation of Antiproliferative Properties of Novel Organotin(IV) Carboxylate Compounds with Propanoic Acid Derivatives on a Panel of Human Cancer Cell Lines

The synthesis of novel triphenyltin(IV) compounds, Ph₃SnLn (n = 1–3), with oxaprozin (3-(4,5-diphenyloxazol-2-yl)propanoic acid), HL1, and the new propanoic acid derivatives 3-(4,5-bis(4-methoxylphenyl)oxazol-2-yl)propanoic acid, HL2, and 3-(2,5-dioxo-4,4-diphenylimidazolidin-1-yl)propanoic acid, HL3, has been performed. The ligands represent commercial drugs or their derivatives and the tin complexes have been characterized by standard analytical methods. The in vitro antiproliferative activity of both ligands and organotin(IV) compounds has been evaluated on the following tumour cell lines: human prostate cancer (PC-3), human colorectal adenocarcinoma (HT-29), breast cancer (MCF-7), and hepatocellular cancer (HepG2), as well as on normal mouse embryonic fibroblast cells (NIH3T3) with the aid of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-12 diphenyltetrazolium bromide) and CV (crystal violet) assays. Contrary to the inactive ligand precursors, all organotin(IV) carboxylates showed very good activity with IC₅₀ values ranging from 0.100 to 0.758 µM. According to the CV assay (IC₅₀ = 0.218 ± 0.025 µM), complex Ph₃SnL1 demonstrated the highest cytotoxicity against the caspase 3 deficient MCF-7 cell line. Inductively coupled plasma mass spectrometry (ICP-MS) analysis indicated a two-fold lower concentration of tin in MCF-7 cells in comparison to platinum. To investigate the mechanism of action of the compound Ph₃SnL1 on MCF-7 cells, morphological, autophagy and cell cycle analysis, as well as the activation of caspase and ROS/RNS and NO production, has been performed. Results suggest that Ph₃SnL1 induces caspase-independent apoptosis in MCF-7 cells.     

Enzyme Design from the Bottom Up: An Active Nickel Electrocatalyst with a Structured Peptide Outer Coordination Sphere

Catalytic, peptide‐containing metal complexes with a well‐defined peptide structure have the potential to enhance molecular catalysts through an enzyme‐like outer coordination sphere. Here, we report the synthesis and characterization of an active, peptide‐based metal complex built upon the well‐characterized hydrogen production catalyst [Ni(P^Ph₂N^Ph)₂]²⁺ (P^Ph₂N^Ph=1,3,6‐triphenyl‐1‐aza‐3,6‐diphosphacycloheptane). The incorporated peptide maintains its β‐hairpin structure when appended to the metal core, and the electrocatalytic activity of the peptide‐based metal complex (≈100,000 s^?1) is enhanced compared to the parent complex ([Ni(P^Ph₂N^APPA)₂]²⁺; ≈50,500 s^‐1). The combination of an active molecular catalyst with a structured peptide provides a scaffold that permits the incorporation of features of an enzyme‐like outer‐coordination sphere necessary to create molecular electrocatalysts with enhanced functionality.     

«3-Fluorisopren» (2-Fluor-3-methyl-1,3-butadien) und einige heterosubstituierte Abkömmlinge

‘3-Fluoroisoprene’ (2-Fluoro-3-methyl-1,3-butadiene) and Some Hetero-substituted Derivatives Thereof The readily accessible 1-chloro-1-fluoro-2-iodomethyl-2-methylcyclopropane undergoes zinc-promoted ring-cleavage yielding 2-fluoro-3-methyl-1, 3-butadiene (‘3-fluoroisoprene’) in almost quantitative yield. Alternatively the iodine atom may be replaced by electron-attracting groups such as cyano, benzenesulfonyl or triphenylphosphonio. Ring-opening of the resulting derivatives can then be brought about by various bases and leads to substituted fluorodienes. - The chemical reactivity of ‘3-fluoroisoprene’ has been studied in some detail. For example, it was found to add bromine at temperatures below 0° under kinetic control and to afford mainly the 1,4-adduct having the (Z)-configuration besides smaller quantities of the 1,2- and 3,4-adduct. At room temperature this mixture slowly undergoes a transformation yielding, as the sole products, both stereoisomeric 1, 4-adducts in a 1:1 ratio.     

Bicyclic graphs for which the least eigenvalue is minimum

The spread of a graph is defined to be the difference between the greatest eigenvalue and the least eigenvalue of the adjacency matrix of the graph. In this paper we determine the unique graph with minimum least eigenvalue among all connected bicyclic graphs of order n. Also, we determine the unique graph with maximum spread in this class for each n?28.     

Stochastic upscaling of random microstructures

In this work we present an upscaling technique for multi-scale computations based on random microstructures modelled as realisations of lognormally distributed random fields, or described by randomly distributed inclusions in a homogeneous matrix. Their corresponding coarse-scale model parameters are considered as uncertain, and are approximated by random variables, the distributions of which are obtained via polynomial chaos based Bayesian procedures in which the fine-scale energy is used as an observation. (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Fluororganische Synthesen IV, 1-Fluor-1-organyl-cyclopropane und andere Cyclopropan-Derivate durch Anlagerungsreaktion von «Nachfolge-Carbenen»

Fluoroorganic Syntheses IV: 1-Fluoro-1-organyl-cyclopropanes and other Cyclopropane Derivatives by Addition of ?Successor-Carbenes”? Treatment of chlorodifluormethane or dichlorodifluoromethane with methyllithium in the presence of an olefin affords 1-fluoro-1-methylcyclopropanes in fair yields. Depending on the particular reaction conditions, 1,1-difluorocyclopropanes, 1,1-dimethylcyclopropanes and 1-chloro-1-methylcyclopropanes may be obtained as well. Butyllithium and phenyllithium give rise to analogous products.     

On bipartite graphs with small number of laplacian eigenvalues greater than two and three

All connected bipartite graphs with exactly two Laplacian eigenvalues greater than two are determined. Besides, all connected bipartite graphs with exactly one Laplacian eigenvalue greater than three are determined.