Triarylborane Dyes as a Novel Non-Covalent and Non-Inhibitive Fluorimetric Markers for DPP III Enzyme

Novel dyes were prepared by simple “click CuAAC” attachment of a triarylborane–alkyne to the azide side chain of an amino acid yielding triarylborane dye 1 which was conjugated with pyrene (dye 2) forming a triarylborane–pyrene FRET pair. In contrast to previous cationic triarylboranes, the novel neutral dyes interact only with proteins, while their affinity to DNA/RNA is completely abolished. Both the reference triarylborane amino acid and triarylborane–pyrene conjugate bind to BSA and the hDPP III enzyme with high affinities, exhibiting a strong (up to 100-fold) fluorescence increase, whereby the triarylborane–pyrene conjugate additionally retained FRET upon binding to the protein. Furthermore, the triarylborane dyes, upon binding to the hDPP III enzyme, did not impair its enzymatic activity under a wide range of experimental conditions, thus being the first non-covalent fluorimetric markers for hDPP III, also applicable during enzymatic reactions with hDPP III substrates.     

Biodegradable Materials from Agro-Based By-Products

Summary: A new biodegradable thermoplastic material based on a wheat flour by-product has been developed. The influence of various additives (glycerol, silica) and fibers (flax, cotton, hemp) on the mechanical properties of the material has been investigated. The development of expanded materials is also presented.     

Diophantine quadruples in $\mathbb {Z}[\sqrt {4k+3}]$

It this paper, we study the existence of Diophantine quadruples with property D(z) in the ring , where d is such that the Pellian equation x ²−dy ²=±2 is solvable. This existence is characterized by the representability of z as a difference of two squares.      

Hydantoin derivatives of L- and D-amino acids: synthesis and evaluation of their antiviral and antitumoral activity

3,5-Disubstituted hydantoin (1,3-imidazolidinedione) derivatives 5a-h were prepared by base induced cyclization of the corresponding N-(1-benzotriazolecarbonyl)-L- and D-amino acid amides 4a-h. Compounds 5a-h were evaluated for their cytostatic and antiviral activities. Among all the compounds evaluated, 3-benzhydryl-5-isopropyl hydantoin (5a) showed a weak but selective inhibitory effect against vaccinia virus (EC(50) = 16 microg/mL; selectivity index: 25). 3-Cyclohexyl-5-phenyl hydantoin (5g) showed inhibitory activity against cervical carcinoma (HeLa, IC(50) = 5.4 microM) and breast carcinoma (MCF-7, IC(50) = 2 microM), but also cytotoxic effects towards human normal fibroblasts (WI 38). On the contrary, the 3-benzhydryl-5-phenyl substituted hydantoin derivative 5h showed moderate inhibitory activity towards HeLa, MCF-7, pancreatic carcinoma (MiaPaCa-2), lung carcinoma (H 460) and colon carcinoma (SW 620) (IC(50) = 20-23 microM), but no effect on WI 38.     

Effect of the remaining lanthanide catalysts on the hydrolytic and enzymatic degradation of poly-(ϵ-caprolactone)

Poly-(ϵ-caprolactone) is a biodegradable polymer, which can be used for both medical and environmental applications. Due to its multiple applications the synthesis of such a polymer has been attracting an increasing attention in the past few decades. In our work, the polymers were synthesised by bulk polymerisation, using different lanthanide halides as initiators. The lanthanide derivatives are known as very active catalysts in the ring-opening polymerisation of cyclic esters. Moreover, they are not toxic in comparison of catalysts, which are usually used for this synthesis. In this paper, the influence of the lanthanides on both the hydrolytic and enzymatic degradation of the PCL obtained by ring-opening polymerization of ϵ-caprolactone with different lanthanide-based catalysts such as: lanthane chloride (LaCl₃), ytterbium chloride (YbCl₃) and samarium chloride (SmCl₃) was assessed. Samarium seems to slightly accelerate the hydrolytic degradation of the polymer and to slow down or inhibit its enzymatic degradation, mainly when the molecular weight of the polymer is high. The behaviour of PCL containing another lanthanide like lanthane is dependent on the nature of the metallic ion. Complete degradation, by the Lipase PS from Pseudomonas cepacia, is achieved only with Ytterbium.     

Optimal taxation of a perfectly competitive firm with Cobb–Douglas production function as a bilevel programming problem

Central European Journal of Operations Research - Taxation is one of the most powerful instruments of fiscal policy, affecting economic growth and investments, as well as competitiveness of...