Synthesis,anticancer and antiviral activities of novel thiopyrano[2,3-d]thiazole-6-carbaldehydes

Novel rel-(6R,7R)-2-oxo-7-phenyl-3,5,6,7-tetrahydro-2H-thiopyrano[2,3-d]thiazole-6-carbaldehydes were synthesized via regio- and diastereoselective hetero-Diels-Alder reaction of 5-arylidene-4-thioxo-2-thiazolidinones with acrolein. The synthesized compounds were evaluated for anticancer and antiviral activities by the National Institutes of Health (NIH) following US NCI and AACF protocols. Anticancer activity screening on NCI60 cell lines allowed identification of 7-phenyl-2-oxo-7-phenyl-3,5,6,7-tetrahydro-2H-thiopyrano[2,3-d]thiazole-6-carbaldehyde 3a with the highest level of antimitotic activity against leukemia with mean GI₅₀/TGI values 1.26/25.22 μM. The screening of antiviral activity lead to identification of 7-(4-methoxyphenyl)-2-oxo-3,5,6,7-tetrahydro-2H-thiopyrano[2,3-d]thiazole-6-carbaldehyde 3b with a promising influence on EBV virus (EC₅₀ = 0.07 μM, SI = 3279) and moderate effect on Herpes simplex virus type 1 and Varicella zoster virus and 7-[4-(benzyloxy)phenyl]-2-oxo-3,5,6,7-tetrahydro-2H-thiopyrano[2,3-d][1,3]thiazole-6-carbaldehyde 3e with a promising influence on Hepatitis C virus (EC₅₀ = 12.6 μM, SI = 43.1).     

Coordination compounds based on CAPh type ligand: synthesis,structural characteristics and luminescence properties of tetrakis-complexes CsLnL4 with dimethylbenzoylamidophosphate

Searching for prospective luminescent materials, the series of new lanthanide coordination compounds CsLnL₄ (Ln = La, Pr, Nd, Sm – Er, and Yb; L^? = {C₆H₅CONPO(OCH₃)₂}^-) was synthesized. X-ray diffraction studies of CsNdL₄ and CsYbL₄ have been performed establishing polymeric structures of the tetrakis-complexes built from [LnL₄]^? anions and cesium cations functioning as linkers. The IR, absorption, emission, excitation spectra, and decay time measurements at 298 and 77 K, as well as thermal gravimetric analyses, were used to characterize the complexes.     

β-Cyclodextrin-containing pseudorotaxanes as building blocks for cross-linked polymers

Rotaxanes and pseudorotaxanes are the supramolecular objects that attract much attention due to their low toxicity, sliding, dethreading and easy modification. Thus, polyrotaxanes and polypseudorotaxanes can be considered as components in drug delivery systems, sensor devices, implants, contrasting agents, fluorescent probes in other diagnostic systems. Therefore, we have prepared the pseudorotaxanes based on the β-cyclodextrin (β-CD) and molecule-“guest”—polyoxypropylenedimethacrylate (POPDMA) as carrier of end-capped methacrylate groups. The presence of such groups allows pseudorotaxane to be co-polymerized with acrylamide and methylene-bis-acrylamide and to develop cross-linked polymer matrices, which implies their further investigation as systems for a drug release. The structure of these substances was confirmed by FTIR- and NMR-spectroscopy, differential scanning calorimetry (DSC), X-ray analysis [wide-angle X-ray scattering (WAXS)], pyrolysis mass spectrometry. The ratio of POPDMA to β-CD was found to be 1:3, according to NMR data. The interactions between β-CD and POPDMA in the aqueous solution and in the dry mechanical mixture are entirely different, due to formation of pseudorotaxane. The results obtained by pyrolysis mass-spectrometry, WAXS and DSC well correlate with mechanism of formation of inclusion complexes, involving a linear molecule and cyclodextrins as described earlier.     

Modeling of Hierarchical Morphology of Carbon Nanotube Bundles in Polymer Composites

The morphological features of carbon nanotube (CNT) polymer composites and their influence on the effective modulus are evaluated. The considered features include bundle formation from the helical sub‐bundles made of individual CNTs. The formation of bundles is considered as a result of agglomeration of individual nanotubes above and below onset of percolation and is related to electrical conductivity. The proposed geometrical model yields a bundle diameter that agrees closely with that of the experimentally measured by voltage‐contrast method and scanning electron microscopy analysis of polyimide nanocomposites. The proposed micromechanical analytical model includes the helical structure of a bundle and provides close agreement of the effective Young's modulus of nanocomposite over a wide range of CNT content. It is shown that considering the helical structure of CNT bundles and its effect on bundle modulus is vital for predicting the effective modulus of CNT‐polymer nanocomposite.

     

Efficient Emission Facilitated by Multiple Energy Level Transitions in Uniform Graphitic Carbon Nitride Films Deposited by Thermal Vapor Condensation

Graphitic carbon nitride (g‐CN) films are important components of optoelectronic devices, but current techniques for their production, such as drop casting and spin coating, fail to deliver uniform and pinhole‐free g‐CN films on solid substrates. Here, versatile, cost‐effective, and large‐area growth of uniform and pinhole‐free g‐CN films is achieved by using a thermal vapor condensation method under atmospheric pressure. A comparison of the X‐ray diffraction and Fourier transform infrared data with the calculated infrared spectrum confirmed the graphitic build‐up of films composed of tri‐s‐triazine units. These g‐CN films possess multiple active energy states including π*, π, and lone‐pair states, which facilitate their efficient (6 % quantum yield in the solid state) photoluminescence, as confirmed by both experimental measurements and theoretical calculations.     

Structure-Morphology-Antimicrobial and Antiviral Activity Relationship in Silver-Containing Nanocomposites Based on Polylactide

Green synthesis of silver-containing nanocomposites based on polylactide (PLA) was carried out in two ways. With the use of green tea extract, Ag⁺ ions were reduced to silver nanoparticles with their subsequent introduction into the PLA (mechanical method) and Ag⁺ ions were reduced in the polymer matrix of PLA-AgPalmitate (PLA-AgPalm) (in situ method). Structure, morphology and thermophysical properties of nanocomposites PLA-Ag were studied by FTIR spectroscopy, wide-angle X-ray scattering (WAXS), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) methods. The antimicrobial, antiviral, and cytotoxic properties were studied as well. It was found that the mechanical method provides the average size of silver nanoparticles in the PLA of about 16 nm, while in the formation of samples by the in situ method their average size was 3.7 nm. The strong influence of smaller silver nanoparticles (3.7 nm) on the properties of nanocomposites was revealed, as with increasing nanosilver concentration the heat resistance and glass transition temperature of the samples decreases, while the influence of larger particles (16 nm) on these parameters was not detected. It was shown that silver-containing nanocomposites formed in situ demonstrate antimicrobial activity against gram-positive bacterium S. aureus, gram-negative bacteria E. coli, P. aeruginosa, and the fungal pathogen of C. albicans, and the activity of the samples increases with increasing nanoparticle concentration. Silver-containing nanocomposites formed by the mechanical method have not shown antimicrobial activity. The relative antiviral activity of nanocomposites obtained by two methods against influenza A virus, and adenovirus serotype 2 was also revealed. The obtained nanocomposites were not-cytotoxic, and they did not inhibit the viability of MDCK or Hep-2 cell cultures.     

Spectral parameter power series for arbitrary order linear differential equations

Let L be the n‐th order linear differential operator Ly=?₀y⁽ⁿ⁾+?₁y^(n?1)+?+?_ny with variable coefficients. A representation is given for n linearly independent solutions of Ly=λry as power series in λ, generalizing the SPPS (spectral parameter power series) solution that has been previously developed for n=2. The coefficient functions in these series are obtained by recursively iterating a simple integration process, beginning with a solution system for λ=0. It is shown how to obtain such an initializing system working upwards from equations of lower order. The values of the successive derivatives of the power series solutions at the basepoint of integration are given, which provides a technique for numerical solution of n‐th order initial value problems and spectral problems.     

Light-Ion Linear Accelerator for the NICA Project

Physics of Particles and Nuclei Letters - A joint team from the Joint Institute for Nuclear Research (JINR) (Dubna, Russia) and Bevatech GmbH (Frankfurt-am-Main, Germany) has been developing a new...     

Solution of parabolic free boundary problems using transmuted heat polynomials

A numerical method for free boundary problems for the equation is proposed. The method is based on recent results from transmutation operators theory allowing one to construct efficiently a complete system of solutions for the above equation, generalizing the system of heat polynomials. The corresponding implementation algorithm is presented.     

A method for computation of scattering amplitudes and Green functions of whole axis problems

A method for the computation of scattering data and of the Green function for the one‐dimensional Schrödinger operator with a decaying potential is presented. It is based on representations for the Jost solutions in the case of a compactly supported potential obtained in terms of Neumann series of Bessel functions (NSBF). The representations are used for calculating a complete orthonormal system of generalized eigenfunctions of the operator H, which in turn allow one to compute the scattering amplitudes and the Green function of the operator H?λ with .