Kulinkovich-type reactions of thioamides: similar to those of carboxylic amides?

The behaviour of thioamides under Kulinkovich-type conditions is compared with the known reactivity of carboxylic amides. Dramatic differences are disclosed.     

Copper(I)‐catalyzed multicomponent reactions in sustainable media

Multicomponent reactions including Biginelli reaction and A³ coupling are useful synthetic methodologies as they can provide valuable intermediates and building blocks for the synthesis of bioactive natural compounds. The heterocyclic products of these transformations represent antibacterial, antitumor or anti‐inflammatory properties. In presented study, copper‐mediated protocols for Biginelli reaction and A³ coupling in sustainable solvents were reported. At first, charged NHC copper complexes were synthesized in few steps and characterized using spectroscopic methods followed by preliminary activity tests in sustainable media. Later in this study, Biginelli reaction and A³ coupling were proceeded using prepared copper catalytic systems under mild conditions. Desired nitrogen‐bearing products were obtained with moderate to very high yields. Some attempts to recycle one of the received NHC copper initiators were also investigated.     

Determination of uranium and selected elements in Polish dictyonema shales and sandstones by ICP-MS

Inductively coupled plasma mass spectrometry was used for characterization of Polish dictyonema shales and sandstones as a potential source of uranium and other technologically important elements. Influence of sample digestion of these materials for the determinations: U, Th, Cu, Co, Mn, Zn, La, V, Yb, Mo, Ni, Sb and Fe has been tested. The method involved two-step microwave acid digestion, followed by direct determination by ICP-MS. The instrument used for all determinations was ELAN DRC II (Perkin Elmer) with crossflow nebulizer with Scott double-pass spray chamber and Ni cones. Certified Reference Materials were used as a quality control standard to validate the applied analytical procedure. The expanded measurement uncertainty U (k = 2) ranged from 5 to 15 %, in dependence on the element. The obtained results provided information on the contents of minor and trace elements in shales and sandstones depending on their origin. At this moment, these geological deposits can be treated as a potential source of raw elements.     

Evaluation of waste products in the synthesis of surfactants by yeasts

The highest yields of biosurfactants were obtained by: (i) Pseudozyma antarctica (107.2 g L^?1) cultivated in a medium containing post-refining waste; (ii) Pseudozyma aphidis (77.7 g L^?1); and (iii) Starmerella bombicola (93.8 g L^?1) both cultivated in a medium with soapstock; (iv)Pichia jadinii (67.3 g L^?1) cultivated in a medium supplemented with waste frying oil. It was found that the biosurfactant synthesis yield increased in all strains when the cell surface hydrophobicity reached 70–80 %, enabling the microbial cells to make good contact with hydrophobic substrates. The lowest surface tension of the post-cultivation medium was from 32.0 mN m^?1 to 37.8 mN m^?1. However, this parameter (which was also determined by a drop collapse assay) was of limited use in monitoring biosurfactant synthesis in this study. The crude glycerol was not a good substrate for biosurfactant synthesis although, in the case of P. aphidis, 67.4 g L^?1 of biosurfactants were obtained after cultivation in the medium supplemented with glycerol fraction (GF2). In a low-cost medium containing soapstock and whey permeate or molasses, about 90 g L^?1 of mannosylerythritol lipids were synthesised by P. aphidis and approximately 40 g L^?1 by P. antarctica.     

Application of Green Algal Planktochlorella nurekis Biomasses to Modulate Growth of Selected Microbial Species

As microalgae are producers of proteins, lipids, polysaccharides, pigments, vitamins and unique secondary metabolites, microalgal biotechnology has gained attention in recent decades. Microalgae can be used for biomass production and to obtain biotechnologically important products. Here, we present the application of a method of producing a natural, biologically active composite obtained from unicellular microalgae of the genus Planktochlorella sp. as a modulator of the growth of microorganisms that can be used in the cosmetics and pharmaceutical industries by exploiting the phenomenon of photo-reprogramming of metabolism. The combination of red and blue light allows the collection of biomass with unique biochemical profiles, especially fatty acid composition (Patent Application P.429620). The ethanolic and water extracts of algae biomass inhibited the growth of a number of pathogenic bacteria, namely Enterococcus faecalis, Staphylococcus aureus PCM 458, Streptococcus pyogenes PCM 2318, Pseudomonas aeruginosa, Escherichia coli PCM 2209 and Candida albicans ATCC 14053. The algal biocomposite obtained according to our procedure can be used also as a prebiotic supplement. The presented technology may allow the limitation of the use of antibiotics and environmentally harmful chemicals commonly used in preparations against Enterococcus faecalis, Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa, Escherichia coli or Candida spp.     

Influence of percentage of guanine molecules, OH radicals, UV irradiation and temperature on electrooxidation of short synthetic oligonucleotides

The electrooxidation of short synthetic 20-nucleotides DNA sequences with various amount of guanine molecules has been studied in a wide temperature range by square wave voltammetry and the results were compared with UV-vis and CD spectra. A twofold increase of dsDNA voltammetric peak, related to an increase in the number of electrons transferred in the guanine electrooxidation process was found to begin at a temperature lower by circa 20 °C compared to the well known increase of the dsDNA absorbance upon denaturation. Since the dsDNA voltammetric peaks are related directly to the electrooxidation of guanine and adenine, early conformational changes in dsDNA are responsible for this effect. An increase in percentage of guanine in the DNA chains caused a delay in the conformational, predenaturation changes. An exception to this behavior was found for polyguanine (100% guanine). Interestingly, two distinct ranges of change in ellipticity in the CD spectra correlate well with the changes obtained by voltammetry. We have also checked the influence of OH radicals and UV irradiation on the dsDNA oxidation.     

Inhibition of inflammatory mediators by neobavaisoflavone in activated RAW264.7 macrophages

Flavonoids and coumarins are the major bioactive constituents identified in Psoralea corylifolia. The active fraction isolated from fruits, seeds and roots possesses antibacterial, antioxidative and immunomodulatory properties. Neobavaisoflavone is one of the flavonoids found in Psoralea corylifolia. In the present study we investigated in vitro the anti-inflammatory activity of neobavaisoflavone. Macrophages play an important role in inflammation through the release of inflammatory mediators involved in the immune response. Inappropriate and prolonged macrophage activation is largely responsible for the pathology of acute and chronic inflammatory conditions. Neobavaisoflavone significantly inhibited the production of reactive oxygen species (ROS), reactive nitrogen species (RNS) and cytokines: IL-1β, IL-6, IL-12p40, IL-12p70, TNF-α in LPS+IFN-γ- or PMA- stimulated RAW264.7 macrophages.     

Analysis of an Active Deformylation Mechanism of 5‐Formyl‐deoxycytidine (fdC) in Stem Cells

The removal of 5‐methyl‐deoxycytidine (mdC) from promoter elements is associated with reactivation of the silenced corresponding genes. It takes place through an active demethylation process involving the oxidation of mdC to 5‐hydroxymethyl‐deoxycytidine (hmdC) and further on to 5‐formyl‐deoxycytidine (fdC) and 5‐carboxy‐deoxycytidine (cadC) with the help of α‐ketoglutarate‐dependent Tet oxygenases. The next step can occur through the action of a glycosylase (TDG), which cleaves fdC out of the genome for replacement by dC. A second pathway is proposed to involve C?C bond cleavage that converts fdC directly into dC. A 6‐aza‐5‐formyl‐deoxycytidine (a‐fdC) probe molecule was synthesized and fed to various somatic cell lines and induced mouse embryonic stem cells, together with a 2′‐fluorinated fdC analogue (F‐fdC). While deformylation of F‐fdC was clearly observed in vivo, it did not occur with a‐fdC, thus suggesting that the C?C bond‐cleaving deformylation is initiated by nucleophilic activation.     

Synthetic control over magnetic moment and exchange bias in all-oxide materials encapsulated within a spherical protein cage

This work focuses on the synthetic control of magnetic properties of mixed oxide magnetic nanoparticles of the general formula Fe(3-x)Co(x)O(4) (x < or = 0.33) in the protein cage ferritin. In this biomimetic approach, variations in the chemical synthesis result in the formation of single-phase Fe(3-x)Co(x)O(4) alloys or intimately mixed binary phase Fe/Co oxides, modifying the chemical structure and magnetic behavior of these particles, as characterized by static and dynamic magnetization measurements and X-ray absorption spectroscopy.     

Sewage sludge ash as an alternative low-cost oxygen carrier for chemical looping combustion

In this paper, novel low-cost oxygen carriers containing Fe₂O₃ are evaluated for use in chemical looping combustion. Sewage sludge ashes and reference samples were prepared and used in cyclic reduction and oxidation experiments in a thermogravimetric analyzer (TG). A gaseous (3 % H₂) fuel and a solid fuel (hard coal) were tested. Three-cycle CLC tests were carried out in the 600–800 °C temperature range and long-term testing was performed at 950 °C. A reactivity study showed that the natural sewage sludge ash sample was stable during the cycling TG tests when hydrogen was used as a fuel at all of the temperatures investigated. Strong temperature effects on the oxygen transport capacity were observed. An one-cycle test at 900 °C showed also that the sewage sludge ash successfully reacted with coal. The oxygen released was fully used for coal combustion, with appreciable reaction rate at temperature of ~750–800 °C, that is significantly lower than that obtained for pure Fe₂O₃-based oxygen carrier. The oxidation reaction was much faster than the reduction reaction. Moreover, the sewage sludge ash showed a low tendency toward agglomeration in the cyclic test, which was superior to the behavior of synthetic materials. The sewage sludge ash exhibited also high mechanical strength, an attrition index of 1 % and a high-temperature resistance of 1,170 °C in a reducing atmosphere. We conclude that sewage sludge ash can be effectively used as a low-cost, valuable oxygen carrier in practical application in chemical looping combustion technology for power generation.