New 1,3,4-Thiadiazole Derivatives with Anticancer Activity

We designed and synthesized the 1,3,4-thiadiazole derivatives differing in the structure of the substituents in C2 and C5 positions. The cytotoxic activity of the obtained compounds was then determined in biological studies using MCF-7 and MDA-MB-231 breast cancer cells and normal cell line (fibroblasts). The results showed that in both breast cancer cell lines, the strongest anti-proliferative activity was exerted by 2-(2-trifluorometylophenylamino)-5-(3-methoxyphenyl)-1,3,4-thiadiazole. The IC₅₀ values of this compound against MCF-7 and MDA-MB-231 breast cancer cells were 49.6 µM and 53.4 µM, respectively. Importantly, all new compounds had weaker cytotoxic activity on normal cell line than on breast cancer cell lines. In silico studies demonstrated a possible multitarget mode of action for the synthesized compounds. The most likely mechanism of action for the new compounds is connected with the activities of Caspase 3 and Caspase 8 and activation of BAX proteins.     

Effect of heat treatment on the structure and morphology of ZnO nanorod array and its composite with titania precursor

ABSTRACT

Effects of the elevated temperature on the structure evolution of the ZnO nanorod array (ZNA) and their hybrid nanocomposite with layered (tetramethyl)ammonium titanate (LTMAT) prepared by the liquid phase deposition were investigated. The vertically oriented ZnO nanorods were deposited on a quartz plate by a chemical bath deposition method and then they were penetrated by the LTMAT using the dip-coating method from the water solution. As a result of such an experimental procedure, an assembly composed of the ZNA with LTMAT was obtained and called hybrid nanocomposite. Since the LTMAT converts to TiO₂ upon subsequent sintering at 350 °C, it can be regarded as TiO₂ precursor for the thermal treatment experiments. The experiments with ZNA and their hybrid nanocomposite at the elevated temperature revealed coalescence of the deposited ZnO nanorods and crystallization of zinc titanate with Zn₂TiO₄ stoichiometry.     

Removal of graffiti from the mortar by using Q-switched Nd:YAG laser

This paper presents part of the larger study on microstructural features of mortars and it's effects on laser cleaning process. It focuses on the influence of surface roughness, porosity and moisture content of mortars on the removal of graffiti by Nd:YAG laser. The properties of this laser are as follows: wavelength (λ) 1.06 μm, energy: 500 mJ per pulse, pulse duration: 10 ns. The investigation shows that the variation of laser fluence with the number of pulses required for the laser cleaning can be divided into two zones, namely effective zone and ineffective zone. There is a linear relationship observed between number of pulses required for laser cleaning and the laser fluence in the effective zone, while the number of pulses required for the laser cleaning is almost constant even though the laser fluence increases in the ineffective zone. Moreover, surface roughness, porosity and moisture content of mortar samples have influence on the laser cleaning process. The effect of these parameters become however negligible at the high level of laser fluence. The number of pulses required for the laser cleaning is low for smooth surface or less porous mortar. Furthermore, the wetness of the samples facilitates the cleaning process.     

A Hierarchical Model of Quantum Anharmonic Oscillators: Critical Point Convergence

We study the two-dimensional gauge theory of the symmetric group S_n describing the statistics of branched n-coverings of Riemann surfaces. We consider the theory defined on the disc and on the sphere in the large-n limit. A non trivial phase structure emerges, with various phases corresponding to different connectivity properties of the covering surface. We show that any gauge theory on a two-dimensional surface of genus zero is equivalent to a random walk on the gauge group manifold: in the case of S_n, one of the phase transitions we find can be interpreted as a cutoff phenomenon in the corresponding random walk. A connection with the theory of phase transitions in random graphs is also pointed out. Finally we discuss how our results may be related to the known phase transitions in Yang-Mills theory. We discover that a cutoff transition occurs also in two dimensional Yang-Mills theory on a sphere, in a large N limit where the coupling constant is scaled with N with an extra logN compared to the standard t Hooft scaling.     

Bridging the Green Gap: Metal–Organic Framework Heteromultilayers Assembled from Porphyrinic Linkers Identified by Using Computational Screening

In organic photovoltaics, porphyrins (PPs) are among the most promising compounds owing to their large absorption cross-section, wide spectral range, and stability. Nevertheless, a precise adjustment of absorption band positions to reach a full coverage of the so-called green gap has not been achieved yet. We demonstrate that a tuning of the PP Q- and Soret bands can be carried out by using a computational approach for which substitution patterns are optimized in silico. The most promising candidate structures were then synthesized. The experimental UV/Vis data for the solvated compounds were in excellent agreement with the theoretical predictions. By attaching further functionalities, which allow the use of PP chromophores as linkers for the assembly of metal-organic frameworks (MOFs), we were able to exploit packing effects resulting in pronounced redshifts, which allowed further optimization of the photophysical properties of PP assemblies. Finally, we use a layer-by-layer method to assemble the PP linkers into surface-mounted MOFs (SURMOFs), thus obtaining high optical quality, homogeneous and crystalline multilayer films. Experimental results are in full accord with the calculations, demonstrating the huge potential of computational screening methods in tailoring MOF and SURMOF photophysical properties.     

Structure,chemical stability and electrical properties of BaCe0.9Y0.1O3−δ modified with V2O5

Wet vacuum impregnation method was applied in order to evaluate the possibility of the formation of the material in BaCe_0.9Y_0.1O_3?δ–V₂O₅ system. Single-phase BaCe_0.9Y_0.1O_3?δ samples, synthesised by solid-state reaction method, were impregnated with the solution of vanadium(V) oxide precursor. Multi-step, multi-cycle impregnation procedure was applied to enhance the impregnation efficiency. Partial decomposition of Y-doped BaCeO₃ in contact with the solution of the precursor, resulting in the formation of vanadium containing phases (CeVO₄ and BaV₂O₆) on the materials surface, was observed. However, the presence of vanadium was also confirmed for the inner parts of the materials. The synthesised materials were submitted for exposition test to evaluate their chemical stability towards CO₂/H₂O. All BaCe_0.9Y_0.1O₃-based materials modified by impregnation revealed higher chemical stability in comparison with single-phase un-modified BaCe_0.9Y_0.1O_3?δ, since the amount of barium carbonate formed during the exposition was significantly lower. The total electrical conductivity of the received multi-phase materials was generally slightly lower than for the reference BaCe_0.9Y_0.1O_3?δ sample, since the presence of the additional phases had a blocking effect on materials conductivity. The values of BaCeO₃ lattice parameters and the Seebeck coefficient did not show the modification of the defects structure of Y-doped BaCeO₃ during applied synthesis procedure.

     

L-argininato copper(II) complexes in solution exert significant selective anticancer and antimicrobial activities

A search for new drugs that overcome the multidrug resistance of microorganisms or are effective against cancer cells prompted us to investigate the binary and ternary Cu(II) complexes containing L-arginine, [CuCl(L-Arg)(phen)]Cl·2H₂O (phen = 1,10-phenanthroline) ( 1 ) and [Cu(L-Arg)₂(H₂O)]C₂O₄·6H₂O ( 2 ), for which crystal and molecular structures were characterized previously. In order to discuss the biological function, the complexes have been screened for their antitumor activity against A549 (human lung cancer cells), HepG2 (human liver hepatocellular carcinoma cells) and antimicrobial activity. To identify the complexes forms existing in the solutions of 1 and 2 crystals, the results obtained from EPR, NIR–Vis–UV and MS (mass spectrometry) measurements were correlated with those from analysis of potentiometric titration of Cu(II)―L-Arg and Cu(II)―L-Arg―phen systems. This comprehensive study indicated that the [Cu(L-Arg)(phen)]²⁺ and [Cu(L-Arg)₂]²⁺ species are dominant in the solution. Complexes 1 and 2 were found to present specific ligand-dependent cytotoxic and antiproliferative potential against cancer cells. They also show antibacterial activity against Gram-positive and Gram-negative bacteria as well as display antifungal properties.     

Atomic Hydrogen Induced Chemical Vapor Deposition of Silicon Oxycarbide Thin Films Derived from Diethoxymethylsilane Precursor

Amorphous silicon oxycarbide (a-SiOC:H) films produced by remote plasma RPCVD from diethoxymethylsilane (DEMS) were characterized in terms of their basic properties related to the coatings deposited using conventional plasma enhanced PECVD method. The effect of substrate temperature (T_S) on the growth rate, chemical composition, structure, and properties of resulting a-SiOC:H films is reported. Film growth is an adsorption-controlled process, wherein two mechanisms can be distinguished with a transition at about T_S=70°C. Depending on the temperature, films of different nature can be obtained, from polymer-like to highly crosslinked material with C-Si-O network. The chemical structure of a-SiOC:H films was characterized by FTIR, ¹³C and ²⁹Si solid-state NMR, and X-ray photoelectron spectroscopes. The a-SiOC:H films were also characterized in terms of their density, refractive index, surface morphology, conformality of coverage, hardness, adhesion to a substrate, and friction coefficient. The films were found to be morphologically homogeneous materials exhibiting good conformality of coverage and small surface roughness. Their refractive index exhibits anomalous effect revealing a minimum value at T_S=125°C. Due to their exceptional physical properties a-SiOC:H films produced by RPCVD from DEMS precursor seems to be useful as potential dielectric materials or coatings for various encapsulation applications.     

Examining the possibilities of applying high pressure to preserve yoghurt supplemented with probiotic bacteria

Natural yoghurt was subject to pressures of 200 and 250 MPa/4 and 18°C/15 min, after which milk-activated inocula of Lactobacillus acidophilus and Bifidobacterium sp. were added. The yoghurts were stored for 4 weeks at refrigeration temperature. After preparation and each week of storage, the count of bacteria, acidity, antibacterial property and an organoleptic assessment was determined. The highest survival rate was demonstrated by the bacteria of Lactobacillus delbrueckii ssp. bulgaricus, Streptococcus thermophilus and Bifidobacterium sp. in the yoghurt pressurised 200 MPa/15min at 4°C. Acidity increases in the control yoghurts were higher than in the pressurised ones. Pressurised yoghurts demonstrated weaker antibacterial effect in comparison to control yoghurts. Slight changes in the smell and taste were observed after pressurisation. Yoghurts pressurised at 18°C were characterised by more favourable organoleptic properties. Better conciseness of the curd and lower whey seep out were observed in pressurised yoghurt.     

Molecular properties with dual basis set methods

The dual basis set approach has proven to be very successful for accurately estimating total energies with large basis sets. This study extends the applications of this technique to the calculation of molecular properties, including energy derivatives with respect to nuclear positions and to an external electric field. All energy derivatives have been calculated numerically via finite-differences. Molecular gradients and Hessians as well as dipole moments and polarizabilites have been calculated at the HF and MP2 levels using two alternative versions of the dual basis set method. The accuracy of these approaches is discussed in the context of quality of basis sets used in calculations. It is shown that even quite poor results obtained with the 6-311G basis set are significantly improved in dual basis set calculations with the 6-311G(d,p) and 6-311G(3df,3dp) basis sets.