Phenanthriporphyrin: An Antiaromatic Aceneporphyrinoid as a Ligand for a Hypervalent Organophosphorus(V) Moiety

The incorporation of a phenanthrene moiety into a porphyrin framework results in the formation of a hybrid macrocycle—phenanthriporphyrin—merging the structural features of polycyclic aromatic hydrocarbons and porphyrins. An antiaromatic aceneporphyrinoid, adopting the trianionic {CCNN} core, is suitable for the incorporation of a phosphorus(V) center to form a hypervalent organophosphorus(V) derivative.     

NKT cell-dependent glycolipid–peptide vaccines with potent anti-tumour activity

It is known that T cells can eliminate tumour cells through recognition of unique or aberrantly expressed antigens presented as peptide epitopes by major histocompatibility complex (MHC) molecules on the tumour cell surface. With recent advances in defining tumour-associated antigens, it should now be possible to devise therapeutic vaccines that expand specific populations of anti-tumour T cells. However there remains a need to develop simpler efficacious synthetic vaccines that possess clinical utility. We present here the synthesis and analysis of vaccines based on conjugation of MHC-binding peptide epitopes to α-galactosylceramide, a glycolipid presented by the nonpolymorphic antigen-presenting molecule CD1d to provoke the stimulatory activity of type I natural killer T (NKT) cells. The chemical design incorporates an enzymatically cleavable linker that effects controlled release of the active components in vivo. Chemical and biological analysis of different linkages with different enzymatic targets enabled selection of a synthetic vaccine construct with potent therapeutic anti-tumour activity in mice, and marked in vitro activity in human blood.     

Trace metal analyses in honey samples from selected countries. A potential use in bio-monitoring

Honey is a sweet product made by bees using nectar from flowers. Concentrations of Ca, K, Mg, Fe, Zn, Mn, Cu, Pb and Cd were determined in 13 honey samples from the selected regions around the world. Levels of Ca, Mg, Cu, Fe, Zn and Mn were measured using flame atomic absorption spectrometry (FAAS). Potassium concentration was determined via flame photometry. Concentrations of Cd and Pb were determined using the electrothermal technique (ETAAS). It was estimated that the examined samples of honey from Greece, Turkey, Spain, Poland, Mexico, Argentina and Italy were of good quality in terms of metal concentrations (compliant with the norms referring to food products – WHO, Fifty-third Report of the joint FAO/WHO Expert Committee on Food Additives; Technical Report Series 776, Geneva), although the analysed samples were not free of heavy metals. The concentrations of the elements in the honey samples ranged from 2.38 to 9.31 μg · g^?1 for Zn, from 3.86 to 35.10 μg · g^?1 for Fe, from 0.19 to 21.64 μg · g^?1 for Mn, from 49.53 to 1006.90 μg · g^?1 for Ca, from 388.25 to 4761.50 μg · g^?1 for K and from 0.20 to 1.53 μg · g^?1 for Cu and regarding heavy metals from 0.11 to 2.78 μg · g^?1 for Pb and from 0.02 to 0.44 μg · g^?1 for Cd. According to these results it was found that the concentrations of heavy metals in the honey samples (except for alfalfa honey and eucalyptus honey from Italy) were under the acceptable limits for foods set out by the FAO/WHO. It was confirmed that the application of chemometric tools supports the extraction of significant information from analytical data, even though the availability of samples is not fully sufficient (this problem is often encountered in environmental analyses).     

The review of versatile application of collagen

This review reports recent advances in the versatile application of collagen. Collagen materials have attracted great attention because they exhibit properties required in cosmetic preparations, in the biomedical field, and in the tanning industry leading to leather production. Herein, the structure and application of collagen are discussed in general, and detailed examples are also drawn from scientific literature and practical work. Copyright © 2016 John Wiley & Sons, Ltd.     

Design,synthesis and application of new bile acid ligands with 1,2,3-triazole ring

New dimers have been obtained from propargyl ester of bile acids and α,α′-diazide-m-xylene by intermolecular 1,3-dipolar cycloaddition. These compounds have been used as ligands to form intermolecular hydrogen bonds with various aromatic acids. The structures of all products were confirmed by spectroscopic (¹H NMR, ¹³C NMR and FT-IR) analysis, mass spectrometry (ESI, MALDI) and PM5 semiempirical methods.     

Effect of composition and drying method on glass transition temperature,water sorption characteristics and surface morphology of newly designed β-lactoglobulin/retinyl palmitate/disaccharides systems

Epoxy-based nanocomposites containing different concentrations (0–3%) of surface-modified graphene nanosheets (GNS) with 3-aminopropyltriethoxysilane were prepared and their thermal and mechanical properties including dynamic mechanical analysis, tensile strength, hardness, and abrasion tests were evaluated in order to have a database for thermo-mechanical properties of epoxy nanocomposites. The main aim of this study was to understand the optimum percentage of GNS which would perform the best reinforcing influence on mechanical and physical performance of an epoxy nanocomposite. The results explain how applying the analysis of variance (ANOVA) method as a useful tool in optimization of GNS concentration in preparation of high-performance epoxy-based nanocomposites.     

Hydrotalcite-derived Co-containing mixed metal oxide catalysts for methanol incineration

The Co–Mg–Al mixed metal oxides were prepared by calcination of co-precipitated hydrotalcite-like precursors at various temperatures (600–800 °C), characterised with respect to chemical (AAS) and phase (XRD) composition, textural parameters (BET), form and aggregation of cobalt species (UV–vis-DRS) and their redox properties (H₂-TPR, cyclic voltammetry). Moreover, the process of thermal decomposition of hydrotalcite-like materials to mixed metal oxide systems was studied by thermogravimetric method combined with the analysis of gaseous decomposition products by mass spectrometry. Calcined hydrotalcite-like materials were tested as catalysts for methanol incineration. Catalytic performance of the oxides depended on cobalt content, Mg/Al ratio and calcination temperature. The catalysts with lower cobalt content, higher Mg/Al ratio and calcined at lower temperatures (600 or 700 °C) were less effective in the process of methanol incineration. In a series of the studied catalysts, the best results, with respect to high catalytic activity and selectivity to CO₂, were obtained for the mixed oxide with Co:Mg:Al molar ratio of 10:57:33 calcined at 800 °C. High activity of this catalyst was likely connected with the presence of a Co–Mg–Al spinel-type phases, containing easy reducible Co³⁺ cations, formed during high-temperature treatment of the hydrotalcite-like precursor.     

How far can we go with Amitsur’s theorem in differential polynomial rings?

A well-known theorem by S. A. Amitsur shows that the Jacobson radical of the polynomial ring R[x] equals I[x] for some nil ideal I of R. In this paper, however, we show that this is not the case for differential polynomial rings, by proving that there is a ring R which is not nil and a derivation D on R such that the differential polynomial ring R[x;D] is Jacobson radical. We also show that, on the other hand, the Amitsur theorem holds for a differential polynomial ring R[x;D], provided that D is a locally nilpotent derivation and R is an algebra over a field of characteristic p > 0. The main idea of the proof introduces a new way of embedding differential polynomial rings into bigger rings, which we name platinum rings, plus a key part of the proof involves the solution of matrix theory-based problems.     

Diffusion-Mediated Transport¶and the Flashing Ratchet

Diffusion-mediated transport is a phenomenon in which a unidirectional motion of particles is achieved as a result of two opposing tendencies: diffusion, which spreads the particles uniformly through the medium and transport, which concentrates the particles at some special sites. The flashing-ratchet version of the Brownian motor, a simple model for protein motors, where the switching between transport and diffusion is periodic, illustrates diffusion-mediated transport. In this paper we show rigorously that the flashing ratchet can be tuned in such a way that the transport of mass against the gradient of the potential takes place and the concentration of mass during the transport phase occurs at sites located at the wells of an asymmetric potential. This goal is accomplished by comparing the flashing ratchet with an approximating Markov chain. A principle achievement of this work is to establish the connection between the dynamics of the ratchet and the Markov chain in the weak^* topology.