Assigning the C-15 configuration of 15-hydroxy-, 15-methoxy-, 15-ethoxy-hexahydrofurofuran neoclerodane diterpenoids

Examination of ¹H and ¹³C NMR spectra allows the establishment of rules for assigning the correct configuration at C-15 of 15-hydroxy-, 15-methoxy-, 15-ethoxy-hexahydrofurofuran neoclerodane diterpenoids. The structure of several diterpenoids has been assigned or ammended.     

Synthesis and solid-state organization of coil-ring-coil block copolymers

Shape-persistent macrocycles based on the phenyl-ethynyl-butadienyl backbone containing two extraannular hydroxyl groups were prepared by the oxidative coupling of the appropriate phenylethynyl oligomers. Carbodiimide-directed coupling with independently synthesized polystyrene carboxylic acid oligomers led to ABA coil-ring-coil block copolymers in which the central macrocycle serves as rigid and the polystyrene oligomers as flexible elements. Depending on the size of the coil blocks, these structures aggregate in cyclohexane into supramolecular hollow cylindrical brushes in which the rigid core is surrounded by the flexible matrix. However, in the solid state it is not possible to identify a morphology in which isolated channels based on aggregated macrocycles are embedded in a matrix of polystyrene. Detailed X-ray and electron diffraction studies on samples prepared from a solution in cyclohexane under equilibrium conditions show that the material adopts a lamellar morphology in the solid state in which columns of macrocycles are aggregated into layers which are separated by polystyrene.     

Qualitative supercritical fluid extraction coupled to capillary gas chromatography

The usefulness and ease of utilizing supercritical fluid extraction (SFE) directly coupled to capillary gas chromatography (GC) as quantitative or qualitative analytical problem-solving tools will be demonstrated. As an alternative to conventional liquid solvent extractions, SFE presents itself as a means to achieve high extraction efficiencies of different compounds in complex solid matrices in very rapid tims frames. Moreover, SFE has an additional advantage of being able to achieve distinct extraction selectivities as a function of the solubilizing power of the supercritical fluid extracting phase. For on-line SFE/GC, the extraction effluent is directly transferred to the analytical chromatograph. On-line SFE/GC involves the decompression of pressurized extraction effluent directly into a heated, unmodified capillary split injection port of the GC. In this respect, SFE introduction into GC can be used as an alternative means of GC injection, comparable to such modes of injection as pyrolysis and thermal desorption. This paper will show applications of SFE/GC where mass spectrometric detection together with flame ionization detection was used for component identification from environmental, tobacco, and petroleum matrices.     

A study on the essential oil of Ferulago campestris: How much does extraction method influence the oil composition?

The essential oil of different parts of Ferulago campestris (Bess.) collected in Sicily has been extracted by microwave-assisted hydrodistillation (MAHD) and by classic hydrodistillation (HD). A comparative qualitative-quantitative study on the composition of the oils was carried out. A total of 100 compounds were identified in the oils obtained by MAHD, whereas 88 compounds characterized the HD oils. The most prominent components were, in all different parts of F. campestris and in both extraction methods, 2,4,5-trimethylbenzaldehyde and 2,4,6-trimethylbenzaldehyde isomers; the latter was not previously found. The attempt to evaluate where the oil components are located in all parts of the plant was carried out by means of a kinetic study. Then, electron microscopy observation on the different parts before and after MAHD and HD was performed.     

Band-gap engineering of metal oxides for dye-sensitized solar cells

Mixed oxides Ti(1-x)Zr(x)O2 with 0 < x < or = 0.2 were synthesized by means of thermal hydrolysis for use in dye-sensitized solar cells. The lattice parameter d is observed to increase linearly with Zr content x. The band gap of the mixed oxides was measured to increase by up to 0.2 eV. The respective shift of the conduction band edge leads to an increase of the open circuit voltage (V(OC)) by up to 0.1 V. Among others, temperature-dependent measurements of V(OC) clearly identify the correlation between band edge shift and change in V(OC).     

Anthemis wiedemanniana essential oil prevents LPS-induced production of NO in RAW 264.7 macrophages and exerts antiproliferative and antibacterial activities in vitro

Anthemis wiedemanniana is known in folk medicine for the treatment of microbial infections, cancer and also urinary and pulmonary problems. In this study, the chemical composition of the essential oil from A. wiedemanniana was evaluated and its antibacterial activity was tested against 10 bacterial strains. The oil was also tested for its potentiality to inhibit nitric oxide production in RAW 264.7 macrophages and for its cytotoxicity against four human cancer cell lines. A. wiedemanniana oil, rich of oxygenated monoterpenes (25.4%), showed a good antibacterial activity against Gram-positive bacteria and a good activity against the two Gram-negative bacteria, Escherichia coli and Proteus vulgaris. Besides that, it exhibited a high inhibitory effect on the LPS-induced nitrite production and a strong cytotoxic activity, especially against amelanotic melanoma (C32) and large lung cell carcinoma (COR-L23) cell lines.     

Indoor radon survey in Eastern Sicily

Inhalation of radon (Rn-222) and its progeny is one of the most significant sources of natural radiation exposure of the population. Nowadays, high radon exposures have been shown to cause lung cancer and many governments all over the world have therefore recommended that radon exposures in dwellings and indoor workplaces should be limited. Radon levels in buildings vary widely from area to area depending on local geology. This paper presents the results of a long-term survey of radon concentrations carried out from 2005 till 2010 in schools and dwellings of Eastern Sicily, using the solid-state nuclear track detector (SSNTD) technique. The investigated area shows medium-high indoor radon concentrations, higher than the Italian average of about 70 Bq/m³, with peaks of 500 Bq/m³ or more in buildings near active faults. Fortunately, only a small fraction of the measurements, about 1.5% of total, was found greater than EU and Italian action limits for indoor and workplaces.     

Supercritical fluid chromatography: A technology update

Summary Significant advances continue to be made in supercritical fluid chromatography both in the instrumentation and application areas. Both packed and wider bore capillary columns are being extensively investigated. Detector designs and interfaces are being reviewed with a great deal of work also going into restrictor and injection technology. The paper focusses on these current developments and how they impact the role of supercritical fluid chromatography in the analytical laboratory.

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Chromatographie mit überkritischen fluiden Phasen: Stand der Technik