Solid-phase microextraction and gas chromatography–mass spectrometry for rapid characterisation of semi-hard cheeses

A headspace solid-phase microextraction (HS-SPME) method in combination with gas chromatography–mass spectrometry (GC–MS) has been used for extraction and identification of components of the volatile fraction of Provola dei Nebrodi, a typical semi-hard Sicilian cheese. Cheese samples from different producers and at different ripening stages have been examined. The effects of various conditions (e.g. sample volume, sample headspace volume, sample heating temperature, extraction time, etc.) on extraction efficiency were studied in order to optimise the technique. The technique used made it possible to identify 61 components: fatty acids from C₂ to C₁₄ and their esters, aldehydes, alcohols, methyl ketones, -lactones, aromatic compounds, hydrocarbons and terpenes. The main components were butanoic, hexanoic and octanoic acids. The linear free fatty acids (FFA) from C₂ to C₁₀ were quantified by using the standard addition method. Calibration curves constructed for the FFA spiked into cheese were highly linear with a correlation coefficient R²>0.998. Significant statistical differences (P0.05) were evident for the even-carbon-number fatty acids during ripening.     

Novel Tyrosine Kinase Inhibitors to Target Chronic Myeloid Leukemia

This paper reports on a novel series of tyrosine kinase inhibitors (TKIs) potentially useful for the treatment of chronic myeloid leukemia (CML). The newly designed and synthesized compounds are structurally related to nilotinib (NIL), a second-generation oral TKI, and to a series of imatinib (IM)-based TKIs, previously reported by our research group, these latter characterized by a hybrid structure between TKIs and heme oxygenase-1 (HO-1) inhibitors. The enzyme HO-1 was selected as an additional target since it is overexpressed in many cases of drug resistance, including CML. The new derivatives 1a–j correctly tackle the chimeric protein BCR-ABL. Therefore, the inhibition of TK was comparable to or higher than NIL and IM for many novel compounds, while most of the new analogs showed only moderate potency against HO-1. Molecular docking studies revealed insights into the binding mode with BCR-ABL and HO-1, providing a structural explanation for the differential activity. Cytotoxicity on K562 CML cells, both NIL-sensitive and -resistant, was evaluated. Notably, some new compounds strongly reduced the viability of K562 sensitive cells.     

Synthesis of some 2,3-Dihydro-11bH-thiazolo[3,2-d][1,4]benzoxazepin-5-(6H)one derivatives. A new heterocyclic ring system

Condensation of (S)-penicillamine methyl or ethyl ester hydrochloride with salicylaldehyde and its C-5 derivatives, provided the diastereomeric thiazolidine derivatives 1 and 2 . The resulting amino function was acylated to afford the amides 3 and 4. Cyclization of the latter led to the 2,3-dihydro-11bH-thiazolo[3,2-d]-[1,4]benzoxazepin-5-(6H)ones 5 and 6. Conformational data for these heterocyclic compounds are discussed.     

An extension of Babbage’s criterion for primality

Let n > 1 and k > 1 be positive integers. We show that if $$\left( {\begin{array}{*{20}c} {n + m} \\ n \\ \end{array} } \right) \equiv 1 (\bmod k)$$ for each integer m with 0 ≤ m ≤ n ? 1, then k is a prime and n is a power of this prime. In particular, this assertion under the hypothesis that n = k implies that n is a prime. This was proved by Babbage, and thus our result may be considered as a generalization of this criterion for primality.     

Counteranion dependent protonation and aggregation of tetrakis(4-sulfonatophenyl)porphyrin in organic solvents

The tetrabutylammonium salt of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) is soluble in dichloromethane, and the general properties of this compound have been investigated as function of various added acids HX (X = Cl, Br, I, CF(3)COO, CF(3)SO(3), TFPB) through UV-vis absorption spectroscopy, steady state fluorescence emission, and resonance light-scattering (RLS) techniques. Upon addition of HX, the initial monomeric free base TPPS is readily converted in an aggregated species, whose spectroscopic features are independent of the nature of the counteranion X. All the spectroscopic evidence suggest a J-type arrangement of chromophores in this aggregate, involving strong hydrogen bonds, electrostatic, and dispersive interactions. In the specific case of chloride and bromide, in the presence of a TBAX excess, the addition of the corresponding acid leads to a monomeric ion-pair between the TBA cations and the diacid TPPS, whose central core is strongly interacting with the halide. On further increasing the acid concentration in these latter solutions, fully protonated species are formed that eventually start to aggregate.     

Synthesis and properties of alkynethiolate gold(I) complexes

A series of alkynethiolate gold(I) derivatives have been synthesised by the cleavage of 4-monosubstituted 1,2,3-thiadiazoles in the presence of strong bases. The syntheses of the 1.2,3-thiadiazoles with p-cyanophenyl, p-tolyl, 2-thienyl, 3-thienyl and 9,9-dimethylfluoren-2-yl fragments are also described. All the complexes have been characterised by spectroscopic techniques and the complexes [Au(p-CH3-C6H4-C[triple bond]C-S)PPh3], [Au(3-C4H3S-C[triple bond]C-S)PPh3] and PPN[Au(p-CH3-C6H4-C[triple bond]C-S)(C6F5)] by X-ray analysis. The electrochemically polymerizable mononuclear bis(alkynethiolate) gold(I) complex PPN[Au(3-C4H3S-C[triple bond]C-S)2] is also described, including its electropolymerization and electrochemical properties.     

FTIR analysis and monitoring of synthetic aviation engine oils

Synthetic turbine oils from military aircraft engines were analysed for antioxidant content and total acid number using infrared (IR) spectroscopy. Two-dimensional IR correlation analysis was employed to investigate and interpret observed trends in the spectra, as acid was formed and antioxidant species were depleted in the oils, as a function of aging and engine wear. Principal components and partial least squares algorithms were used and compared for the development of calibration and prediction models. Transmission IR spectrometry is demonstrated to be effective for the analysis and monitoring of synthetic aviation turbine engine oils and shown to provide rapid and accurate information as compared with traditional analytical techniques and methods.     

Porphyrin deposition induced by UV irradiation

Simple irradiation by UV light of porphyrin TpyP and its zinc(II) and manganese(III) metal derivatives in chlorinated solvents leads to the deposition on silica of mesoscale aggregates. The process is due to the photochemical decomposition of the solvent with generation of HCl, which causes the precipitation of a protonated form. The morphology of the resulting objects is driven by the nature of the inserted metal ion.     

Regioselective one-pot synthesis of 9-alkyl-6-chloropyrido[3,2-e][1,2,4]triazolo[4,3-a]pyrazines. Reactivity of aliphatic and aromatic hydrazides

[reaction: see text] The one-pot synthesis of new 9-alkyl-6-chloropyrido[3,2-e][1,2,4]triazolo[4,3-a]pyrazines has been achieved. Hydrazides regioselectively reacted as nucleophiles with the 3-chloro substituent of 2,3-dichloropyrido[2,3-b]pyrazine. An intramolecular cyclization afforded the tricycle nonxanthine adenosine receptor antagonists.