Antiproliferative and antiinflammatory coxib–combretastatin hybrids suppress cell cycle progression and induce apoptosis of MCF7 breast cancer cells

In our study, some newly synthesized aryl-substituted pyrazole derivatives mimicking cis-diphenylethylene scaffold of two apoptotic inducing agents celecoxib and combretastatin A-4 were found to have strong antiproliferative as well as antiinflammatory activities. Among these coxib–combretastatin hybrids, two lead compounds 8 and 6c simultaneously inhibited prostaglandin E2 (PGE2) production in LPS-activated murine macrophage RAW 264.7 cells and suppressed cell cycle progression of MCF7 cells at G2/M or G0/G1 phases, but only compound 8 induced apoptosis via caspase-3 activation. Both the lead compounds showed good docking energies with both protein targets COX-2 and tubulin in the molecule interaction modeling. The cis-diphenylethylene scaffold of celecoxib or combretastatin A-4 as well as functional groups such as the ethyl ester group and the sulfonamide could be considered as potential key features for the dual activity of studied compounds meanwhile the trimethoxybenzene remained the crucial characterization of the newly derived compounds of combretastatins.

     

Quasi-wave shape of an interface upon explosion welding (copper–tantalum,copper–titanium)

The interface relief of copper–titanium compounds and its evolution upon the intensification of explosion welding are investigated. Typical structures are revealed: splashes, waves consisting of ledges, interrupted waves, and transient states generated by interrupted waves combined into bands. The effect the mutual solubility of the initial elements has on the formation of a welded joint’s structure is determined. Intermetallic compounds are detected both on ledge surfaces and inside areas of local melting.     

Structure elaboration of isoniazid: synthesis,in silico molecular docking and antimycobacterial activity of isoniazid–pyrimidine conjugates

Molecular Diversity - Designing small molecule-based new drug candidates through structure modulation of the existing drugs has drawn considerable attention in view of inevitable emergence of...     

On the region of indifference for high pressure transitions in d-camphor (II–III) and phosphorus (I–II)

An investigation has been made of the effect of pressure on the transformation in d-camphor and phosphorus. The so-called “region of indifference”, reported as approximately 0·6 kilobars (kb) in camphor and approximately 0·38 kb in phosphorus, was found to be less than 0·14 kb and 0·16 kb, respectively. Rates of transformation between phases showed strong dependence on the purity of material, and it is suggested that for sufficiently high purity the region of indifference may become vanishingly small.     

Synthesis and Reactivity of Mg(II)–Fe(II)–Fe(III) Hydroxycarbonates

Green rust-like compounds (GRs) were discovered as natural minerals in various hydromorphic soils, where anoxic conditions allow their stability. They may control some redox processes in aquifers and participate to the transformation of various pollutants. Since Mg(II) cations are present in the fields where GRs were discovered, a partial substitution of Mg(II) to Fe(II) leading to intermediate compounds between GRs and usual Mg(II)–Fe(III) hydroxysalts is suspected. Mg(II)–Fe(II)–Fe(II) hydroxycarbonates can be obtained as intermediate oxidation products of (Mg, Fe)(OH)₂ in carbonate-containing aqueous media obeying to [Fe^II _4(1–x)Mg^II _4x Fe^III ₂(OH)₁₂]²⁺ [CO₃ ^2– nH₂O]^–2. TMS spectra at 12 K are similar to those of GRs, i.e., two quadrupole doublets, one due to Fe(II) with a large isomer shift =1.29 mms^–1 (with respect to -iron at room temperature) and quadrupole splitting E _Q=2.76 mms^–1, the other one due to Fe(III) with smaller hyperfine parameters =0.49 mms^–1 and E _Q=0.44 mms^–1. Fe(II) ions oxidise rapidly into Fe(III) with dissolved O₂. The reactivity is similar to that of Fe(II)–Fe(III) hydroxysalts GR, and thus the potential of Mg(II)–Fe(II)–Fe(III) compounds for reducing pollutants.     

Total asymmetric synthesis of (–)-Phenylhistine, (–)-Aurantiamine and related compounds. Part I

A new general, short, and efficient strategy for the construction of dehydro-diketopiperazines was developed. Horner–Emmons type coupling between a phosphinyl glycine ester and a formyl heterocycle is the key coupling reaction, which proceeds in good-to-excellent yields on several sterically-hindered substrates. Moreover, racemization of the parent L-amino acids is avoided as a result of the mild basic conditions used. The selection of the NH protective group of the formyl heterocycle was crucial. N-tosylated heterocycles proved ideal for this reaction sequence. Thus, the title compounds, (–)-Phenylhistine and (–)-Aurantiamine, were prepared in high yield (four steps, 47% overall) and optical purity. Furthermore, the synthesis of unnatural derivatives including an indole analogue was successfully completed.     

Spectroscopic and Theoretical Study of Cyanidin–Aluminum (III) Complexes

Complexation of aluminum (III) with cyanidin, a natural anthocyanidin molecule, has been investigated in methanol and buffered solutions of pH 3.0 and 4.0. Electronic absorption spectroscopy was performed to characterize the stoichiometry and stability of the complexes formed. In investigated solvents, aluminum bonded moderately to cyanidin requiring large mole ratios of the components (up to 200) for the access of complexation. Molar ratio plots showed the formation of only one complex with stoichiometry aluminum (III):cyanidin of 1∶1 in both investigated media. Semiempirical calculations, performed in the Austin Model 1 parameterization, enabled the determination of the structural features of free compounds as well as complex structural modifications caused by chelation of Al(III).     

Study on the Cofluorescence Effect of Europium (III)–Yttrium (III)–Balofloxacin–Sodium Dodecyl Sulfate System and Its Analytical Application

A new fluorescence enhancement phenomenon in the europium(III)–balofloxacin–sodium dodecyl sulfate system was observed when yttrium(III) was added. Based on this, a sensitive cofluorescence assay for the estimation of balofloxacin was established. Under the optimized conditions, the enhanced fluorescence signal was linear over the concentration of balofloxacin ranging from 3.0 × 10^?9 to 7.0 × 10^?6 mol L^?1 with a correlation coefficient of 0.9993. The detection limit (3 σ) was determined as 8.3 × 10^?10 mol L^?1. The presented method was successfully applied to determination of balofloxacin in pharmaceutical preparations, human serum, and urine. The possible fluorescence enhancement mechanism was also discussed.     

Physical properties and crystal structure of a new semiconducting I–III–VI2 compound,CuScS2

The compound CuScS₂ has been prepared for the first time, and single crystals have been grown by chemical transport reaction with I₂. The crystals are trigonal with a=3·7333±0·0005 , c=6·098±0·001 , and are non-centrosymmetric with space group P3m1. The crystal structure has been determined by single crystal X-ray methods and is based on a hexagonally close packed arrangement of sulfur atoms, with one formula unit per cell. The scandium atoms occupy octahedral sites and the copper atoms tetrahedral sites giving a new structure type intermediate between the structures of NiAs and hexagonal ZnS. The compound is a semiconductor and optical absorption measurements show two band gaps, one at 2·30 eV representing a direct transition and the other at 1·8±1 eV representing an indirect transition. Doping experiments with Zn produced low resistivity n-type material, but attempts to prepare p-type material were unsuccessful.     

LEED surface crystallography,R-factors and the structure of the (110) surfaces of III–V semiconductors

Investigation of InSb(110) is presented which is used as the basis for a study of the way in which R-factors are used in LEED methods. These are general comments on the nature of R-factors and the methodology of LEED appropriate to many of the complex surfaces such as the zincblende (110) surface now being studied.     

A highly luminescent complexes of Eu(III) and Tb(III) with norfloxacin and gatifloxacin doped in sol–gel matrix: A comparable approach of using silica doped Tb(III) and Eu(III) as optical sensor

Highly luminescent complexes of Eu and Tb ions with norfloxacin (NFLX) and gatifloxacin (GFLX) were prepared in sol–gel matrix. The red and green emissions of Eu and Tb ions were obtained by the energy transfer from the triplet state of (NFLX) and (GFLX) to the excited emitting states (⁵D₀ and ⁵D₄) of Eu and Tb, respectively. The intensity of the electric field emission bands (⁵D₀→⁷F₂, 617 nm and ⁵D₄→⁷F₅, 545 nm) of Eu and Tb ions were proportional to the concentration of (NFLX at pH 6.0) and (GFLX at pH 3.5) in acetonitrile with excitation wavelengths (λ_ex) (340 and 395) and (370 and 350 nm) for Eu and Tb ions, respectively. The monitored luminescence intensity of the system showed a good linear relationship with the concentration of NFLX within a range of 5×10^?9–5.8×10^?6 and 5×10^?8–1.0×10^?6 mol L^?1 with a correlation coefficient of 0.990, and for GFLX within a range of 2.4×10^?9–3.2×10^?5 and 5×10^?8–8.0×10^?6 mol L^?1 with a correlation coefficient of 0.995. The detection limit (LOD) was determined as 3.0×10^?9 and 1.0×10^?8 mol L^?1 for NFLX and 1.6×10^?10 and 2.0×10^?8mol L^?1 for GFLX. The limit of quantification (LOQ) is 9×10^?9 and 3.0×10^?8 and 4.8×10^?10 and 6.0×10^?8 in case of Eu and Tb, respectively.     

Effect of copper concentration on atomic site occupation by Fe ions and magnetic properties of (PrDy)–(FeCo)–B alloys

The effect of small copper additions (to ～6 at %) on the distribution of iron ions in six crystallographic sites of the unit cell of the main magnetic phase (PrDy)₂(FeCo)₁₄B has been detected. An increase in the copper concentration leads to a decrease in the 8j₁ site occupation by iron ions. Independently of the presence of copper, the temperature dependences of the saturation magnetization of all samples have a minimum which can correspond to the presence of a low-temperature phase or a compensation point in grain boundary regions of the (PrDy)₂(FeCo)₁₄B main magnetic phase. The alloys under study are not additive sets of all phases in their composition, but behave as new materials with the mutual influence of phases on each other.     

Dissociation pressures of GaAs,GaP and InP and the nature of III–V melts

Direct measurements of the dissociation pressures of GaAs, GaP and InP have been made as a function of temperature by the quartz Bourdon gauge technique. The pressures at the stoichiometric melting points were found to be: for GaAs, 1·00 ± 0·02 atm. at 1238°C; for GaP, 35 ± 10 atm. at 1467°C ± 3°C; and for InP, 21± 5 atm. at 1058°C ± 3°C. These data together with the phase diagram data for the III—V compounds indicate that the melts of these compounds are neither ideal nor regular solutions but show negative excess free energies which are dependent on composition and/or temperature. This result is interpreted as indicative of association of the group V species in these melts.     

Spectroscopic Properties and Electronic Structure of (L-Glutamato)(2, 2′-Bipyridine) copper(II)

Cu(L-glu)(bpy)(L-glu = L-glutamato; bpy = 2, 2′-bipyridine) was prepared. Its electronic absorption spectrum and photoacoustic spectrum were recorded at room temperature. They were compared with each other and compared quantitatively with ligand field theory(LFT) and the radical wave function of non-free ions^[1–3]. Therefore, the electronic structure was also investigated with its spectrum behaviors and PLFT^[1–3].     

CO(III)–NI(II) double substituted bismuth vanadate: synthesis,phase stabilization,and structural and electrical characterization

Samples of Co–Ni double substituted bismuth vanadate, BICO_0.20?x NI _x VOX (Bi₄Co_0.20???x ^(III)Ni _x ^(II)V_1.8O_{10.8???(x/2)???δ} ;0?≤?x?≤?0.20) were synthesized by standard solid state reactions. The influence of Ni substitution for Co on phase stabilization and oxide-ion performance have been investigated using X-ray powder diffraction, differential thermal analysis, and AC impedance spectroscopy. The high conducting γ′-phase was effectively stabilized at room temperature for compositions with x?≥?0.13 whose thermal stability increases with Ni content. The complex plane plots of impedance were typically represented at temperatures below 380 °C, suggesting a major contribution of polycrystalline grains to the overall electrical conductivity. The dielectric permittivity measurements revealed the fact that suppression of the ferroelectric transition is compositionally dependent. Interestingly, the maximum ionic conductivity at lower temperatures (～2.56?×?10^?4 S cm^?1 at 300 °C) was observed for the composition with x?=?0.13. However, a good agreement was generally found between the values of electrical conductivity and corresponding activation energies of conduction.     

Preparation and Tunable Luminescence Properties of Tb(III)-Doped Zinc–Aluminum Hydrotalcite-Like Compounds

Journal of Applied Spectroscopy - Tb3+-doped Zn–Al (Zn–Al–Tb) hydrotalcites with tunable blue-green emission synthesized by co-precipitation. The compositions and properties of...     

Ionicities,effective charges,dielectric constants,and atomic polarizabilities of III–V semiconductors

Relative sharing times of a valence electron are used to calculate particular dielectric constant and polarizabilities of the constituent atoms from optical effective charges and dielectric constants of the compound.     

EPR Studies of DOPA–Melanin Complexes with Fe(III)

Paramagnetic centers in 3,4-dihydroxyphenylalanine–melanin and its complexes with Fe(III) were examined by electron paramagnetic resonance (EPR) spectroscopy. Paramagnetic centers of melanin play an important role in detoxification of environment and they reveal high activity in binding of metal ions. Two different signals were observed in EPR spectra: lines of o-semiquinone free radicals and lines of paramagnetic Fe(III). Amplitudes of EPR lines of both free radicals and iron ions decrease with increasing Fe(III) content in melanin–metal ion complexes. Free radical concentrations in the melanin samples, g-factors, amplitudes and line widths of EPR spectra were determined. It was stated that fast spin–lattice relaxation processes exist in both free radical system and paramagnetic iron ions in melanin complexes.