24 research outputs found
Pierwsze stwierdzenie modraszka wikramy Pseudophilotes vicrama (Moore, 1865) (Lepidoptera: Lycaenidae) w Bieszczadach Zachodnich
First record of Eastern Baton Blue Pseudophilotes vicrama (Moore, 1865) (Lepidoptera: Lycaenidae) in the Western Bieszczady Mts. The paper presents first observation of Eastern Baton Blue Pseudophilotes vicrama (Moore, 1865) in the Western Bieszczady Mts. A single individual was observed on the top of Połonina Wetlińska Range. This site is located approx. 30 km north-east of the known sites in Slovakia and approx. 35 km north of the sites in Ukraine. At the only two known and historical sites in the Podkarpacie Region, near Pruchnik and Jarosław, the species was last observed before 1960
Synthesis, spectroscopy, and theoretical calculations of some 2-thiohydantoin derivatives as possible new fungicides
Hydrolysis of 2,4-dithiophenobarbital
Hydrolysis of 2,4-dithiophenobarbital in aqueous solutions of pH 2 - 12 was investigated at 40 and 60OC using UV spectrophotometry. The values of reaction order, rate constants, pKa1 and pKa2 and activation energy were determined. The preliminary estimation of degradation products was accomplished using thin layer chromatography. The major products were isolated by circular chromatography and identified by spectroscopic and classical methods
5-Arylidenerhodanines as P-gp modulators : an interesting effect of the carboxyl group on ABCB1 function in multidrug-resistant cancer cells
Multidrug resistance (MDR) is considered one of the major mechanisms responsible for the failure of numerous anticancer and antiviral chemotherapies. Various strategies to overcome the MDR phenomenon have been developed, and one of the most attractive research directions is focused on the inhibition of MDR transporters, membrane proteins that extrude cytotoxic drugs from living cells. Here, we report the results of our studies on a series newly synthesized of 5-arylidenerhodanines and their ability to inhibit the ABCB1 efflux pump in mouse T-lymphoma cancer cells. In the series, compounds possessing a triphenylamine moiety and the carboxyl group in their structure were of particular interest. These amphiphilic compounds showed over 17-fold stronger efflux pump inhibitory effects than verapamil. The cytotoxic and antiproliferative effects of target rhodanines on T-lymphoma cells were also investigated. A putative binding mode for 11, one of the most potent P-gp inhibitors tested here, was predicted by molecular docking studies and discussed with regard to the binding mode of verapamil
Derivation of the Supermolecular Interaction Energy from the Monomer Densities in the Density Functional Theory
The density functional theory (DFT) interaction energy of a dimer is
rigorously derived from the monomer densities. To this end, the supermolecular
energy bifunctional is formulated in terms of mutually orthogonal sets of
orbitals of the constituent monomers. The orthogonality condition is preserved
in the solution of the Kohn-Sham equations through the Pauli blockade method.
Numerical implementation of the method provides interaction energies which
agree with those obtained from standard supermolecular calculations within less
than 0.1% error for three example functionals: Slater-Dirac, PBE0 and B3LYP,
and for two model van der Waals dimers: Ne2 and (C2H4)2, and two model H-bond
complexes: (HF)2 and (NH3)2.Comment: 6 pages, 1 figure, REVTeX
Density Functional Theory Approach to Noncovalent Interactions via Interacting Monomer Densities
A recently proposed "DFT+dispersion" treatment (Rajchel et al., Phys. Rev.
Lett., 2010, 104, 163001) is described in detail and illustrated by more
examples. The formalism derives the dispersion-free density functional theory
(DFT) interaction energy and combines it with the dispersion energy from
separate DFT calculations. It consists in the self-consistent polarization of
DFT monomers restrained by the exclusion principle via the Pauli blockade
technique. Within the monomers a complete exchange-correlation potential should
be used, but between them only the exact exchange operates. The applications to
wide range of molecular complexes from rare-gas dimers to H-bonds to
pi-electron interactions show good agreement with benchmark values.Comment: 9 pages, 5 figures, 2 tables, REVTeX