FTIR study of CO adsorption on molybdena-alumina catalysts for surface characterization

CO adsorption at low temperature has been used to probe Lewis acid sites created upon dehydroxylation of γ-Al₂O₃ and reduction of Mo/Al₂O₃ catalysts, using Fourier Transform Infrared spectroscopy (FTIR). Carbon-monoxide adsorption on γ-Al₂O₃ and Mo/Al₂O₃ catalysts dehydroxylated and reduced at different temperatures was studied at 78 K by IR spectroscopy. However, our results indicate that there is an approximately linear correlation between the increase either of dehydroxylation or the extent of reduction of the catalysts and the increasing absorbance of CO due to CO adsorption on Lewis acid sites created upon dehydroxylation of γ-Al₂O₃ and reduction of Mo/Al₂O₃.     

Effect of Poly(methacrylic acid) on the Cytokine Level in an In Vivo Tumor Model

Cancer is a leading cause of mortality globally. Despite remarkable improvements in cancer-treatment approaches, disease recurrence and progression remain major obstacles to therapy. While chemotherapy is still a first-line treatment for a variety of cancers, the focus has shifted to the development and application of new approaches to therapy. Nevertheless, the relationship between immune response, neoplastic diseases and treatment efficiency is not fully understood. Therefore, the aim of the study was to investigate the immunopharmacological effects of methacrylic acid homopolymer in an in vivo tumor model. Materials and methods: Monomeric methacrylic acid was used to synthesize polymers. Methacrylic acid was polymerized in dioxane in the presence of 4-Cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid. To study the molecular weight characteristics of PMAA by GPC, carboxyl groups were preliminarily methylated with diazomethane. An experimental cancer model was obtained by grafting RMK1 breast cancer cells. The serum levels of IL-6, IL-10, IL-17, transforming growth factor β1 (TGF-β1), and tumor necrosis factor α (TNF-α) were measured by ELISA. Results: The effect of PMAA on the serum concentrations of several cytokines was studied upon its single administration to laboratory animals in early neoplastic process. The IL-6, IL-17 and TGF-β1 concentrations were found to change significantly and reach the level observed in intact rats. The IL-10 concentration tended to normalize. Conclusion: The positive results obtained are the basis for further studies on the effect of methacrylic-acid polymers with different molecular-weight characteristics on the neoplastic process.     

Synthesis of tetrazole containing 1,2,3-thiadiazole derivatives via U-4CR and their anti-TMV activity

A series of novel tetrazole containing 1,2,3-thiadiazole derivatives were designed and synthesized via Ugi reaction. Their structures were confirmed by melting points, IR, 1H NMR, and HRMS (ESI). Preliminary bioassay indicated that most target compounds exhibited very good direct anti-TMV activity at 100 μg/mL, which was equal to or higher than that of ribavirin. Among them, compounds 4b, 4c and 4i also showed equivalent protection effect to ribavirin in vivo at 100 μg/mL.     

Unusual stereoselectivity of methionine-γ-lyase from Citrobacterfreundii toward diastereomeric (S)-methionine S-oxide

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Polarizing-alignment layers for twisted nematic cells

We describe polarizing films formed from the lyotropic liquid crystalline phases of dyes dissolved in water. The dye polarizers possess a high dichroic ratio close to that of conventional polarizers. In addition, the dried dye films provide a uniform homogeneous orientation for thermotropic nematic materials. Therefore, thin dye films can simultaneously serve as internal polarizers and as alignment agents. These properties make them especially suitable for twisted nematic devices based on low cost birefringent plastic substrates.     

[6,6]‐Open and [6,6]‐Closed Isomers of C70(CF2): Synthesis,Electrochemical and Quantum Chemical Investigation

Novel difluoromethylenated [70]fullerene derivatives, C₇₀(CF₂)_n (n=1–3), were obtained by the reaction of C₇₀ with sodium difluorochloroacetate. Two major products, isomeric C₇₀(CF₂) mono‐adducts with [6,6]‐open and [6,6]‐closed configurations, were isolated and their homofullerene and methanofullerene structures were reliably determined by a variety of methods that included X‐ray analysis and high‐level spectroscopic techniques. The [6,6]‐open isomer of C₇₀(CF₂) constitutes the first homofullerene example of a non‐hetero [70]fullerene derivative in which functionalisation involves the most reactive bond in the polar region of the cage. Voltammetric estimation of the electron affinity of the C₇₀(CF₂) isomers showed that it is substantially higher for the [6,6]‐open isomer (the 70‐electron π‐conjugated system is retained) than the [6,6]‐closed form, the latter being similar to the electron affinity of pristine C₇₀. In situ ESR spectroelectrochemical investigation of the C₇₀(CF₂) radical anions and DFT calculations of the hyperfine coupling constants provide evidence for the first example of an inter‐conversion between the [6,6]‐closed and [6,6]‐open forms of a cage‐modified fullerene driven by an electrochemical one‐electron transfer. Thus, [6,6]‐closed C₇₀(CF₂) constitutes an interesting example of a redox‐switchable fullerene derivative.     

xMAP-based analysis of three most prevalent staphylococcal toxins in Staphylococcus aureus cultures

Detection of staphylococcal toxins presents a great interest for medical diagnostics. Screening of clinical samples for the presence of several types of staphylococcal toxins using traditional methods—biological tests on animals or cell cultures as well as ELISA—is laborious. Multiplex detection methods would simplify testing. We have designed an xMAP-based assay to detect three staphylococcal toxins—enterotoxins A and B (SEA and SEB) and toxic shock syndrome toxin (TSST)—in cultural supernatants obtained from different strains of Staphylococcus aureus. The limits of detection of SEA, SEB, and TSST multiplex detection in S. aureus growth medium were 10, 1,000, and 5 pg/mL, respectively. Fifty-nine samples of S. aureus cultural supernatants were tested with the xMAP assay. The developed assay has proved highly effective detection of the natural toxins in the samples obtained due to bacterial cells cultivation. In prospect, the developed test system can be used in clinical diagnostics and in monitoring of foodstuffs and environmental objects.