ALBERT

Description: A citrinin dimer, named dicitrinol ( 3 ), was isolated from extracts obtained from a rice cultivation of Penicillium janthinellum , a fungus found in fruits of Melia azedarach. Dicitrinol ( 3 ) was isolated by classical chromatographic procedures, and identified by MS, and 1D- and 2D-NMR data. A biosynthetic scheme is proposed for this new dimerization of citrinin. Dicitrinol ( 3 ) was shown to be slightly weaker than citrinin regarding bacterial inhibition.

Description: Cylindrospermopsin (CYN) is increasingly recognized as a potential threat to drinking water safety, due to its ubiquity. This cyanotoxin has been found to cause toxic effects in mammals, and although fish could be in contact with this toxin, acute toxicity studies on fish are nonexistent. This is the first study showing that single doses of CYN pure standard (200 or 400 μg CYN/kg fish bw) by oral route (gavage) generate histopathological effects in fish (Tilapia— Oreochromis niloticu s) exposed to the toxin under laboratory condition. Among the morphological changes, disorganized parenchymal architecture in the liver, dilated Bowman's space in the kidney, fibrolysis in the heart, necrotic enteritis in the intestines, and hemorrhages in the gills, were observed. Moreover, some oxidative stress biomarkers in the liver and kidney of tilapias were altered. Thus, CYN exposure induced increased protein oxidation products in both organs, NADPH oxidase activity was significantly increased with the kidney being the most affected organ, and decreased GSH contents were also detected in both organs, at the higher dose assayed. © 2012 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Description: RhCl 3 is shown to mediate unusual coupling reactions of tert -butyl acetylene. When RhCl 3 (H 2 O) n was heated with four equivalents of tert -butyl acetylene in methanol, the dinuclear complex [{Rh(μ-Cl)(CH 2 t Bu)( t BuC=CHCOCH 2 t Bu)} 2 ] ( 2 ) was isolated. A larger excess of tert -butyl acetylene (12 equiv.) resulted in the formation of the dimer [{η 5 -C 5 H 2 t Bu 2 (CH 2 t Bu)}Rh(μ-Cl) 3 Rh(C 24 H 42 O 2 )] ( 3 ). Both complexes were analyzed by single-crystal X-ray diffraction.

Description: Alterations of phospholipid (PL) profiles have been associated to disease and specific lipids may be involved in the onset and evolution of cancer; yet, analysis of PL profiles using mass spectrometry (MS) in breast cancer cells is a novel approach. Previously, we reported a lipidomic analysis of PLs from mouse mammary epithelial and breast cancer cells using off-line thin layer chromatography (TLC)-MS, where several changes in PL profile were found to be associated with the degree of malignancy of cells. In the present work, lipidomic analysis has been extended to human mammary epithelial cells and breast cancer cell lines (MCF10A, T47-D and MDA-MB-231), using TLC-MS, validated by hydrophilic interaction liquid chromatography (Hilic-LC)-MS. Differences in phosphatidylethanolamine (PE) content relative to total amount of PLs was highest in non-malignant cells while phosphatidic acid (PA) was present with highest relative abundance in metastatic cells. In addition, the following differences in PL molecular species associated to cancer phenotype, metastatic potential and cell morphology were found: higher levels of alkylacyl PCs and PI (22:5/18:0) were detected in migratory cells, epithelial cells had less unsaturated fatty acyl chains and shorter aliphatic tails in PE and sphingomyelin (SM) classes, while phosphatidylinositol PI (18:0/18:1) was lowest in non-malignant cells compared to cancer cells. To date, information about PL changes in cancer progression is scarce, therefore results presented in this work will be useful as a starting point to define possible PLs with prospective as biomarkers and disclose metabolic pathways with potential for cancer therapy. J. Cell. Physiol. © 2012 Wiley Periodicals, Inc.

Description: On 7 September 2008 a major ash explosion occurred from the SW summit crater of Stromboli volcano. This explosive event lasted ∼2 min and consisted of three discrete eruptive pulses, forming an eruptive ash cloud ∼500–600 m high and ∼300 m wide, rising with speed of 20–27 m s−1. The event was recorded by our camera and seismic networks, as well as by two electric stations installed at a 500 m mean distance from the SW crater. The electric signals recorded by the two stations during this event were 106 times greater than signals recorded during the persistent Strombolian activity, and the seismic trace had a bigger amplitude and a longer duration. Camera image analysis allowed us to infer that a partial obstruction took place at the SW crater three days before the explosive event, suggesting that a constriction within the upper conduit could have likely led to magma overpressure. Data analysis, combined with previous experimental investigations, revealed that the higher energy output of the ash explosion, when compared to the persistent Strombolian activity, resulted in a greater magma fragmentation and erupted mass. Integration of the different parameters allowed us to classify the event as a Vulcanian type, and electric signal analysis enabled retrieval of the total volume of erupted ash and of the amounts of the juvenile, phreatomagmatic, and lithic components.

Description: RhCl 3 is shown to mediate unusual coupling reactions of tert -butyl acetylene. When RhCl 3 (H 2 O) n was heated with four equivalents of tert -butyl acetylene in methanol, the dinuclear complex [{Rh(μ-Cl)(CH 2 t Bu)( t BuC=CHCOCH 2 t Bu)} 2 ] ( 2 ) was isolated. A larger excess of tert -butyl acetylene (12 equiv.) resulted in the formation of the dimer [{η 5 -C 5 H 2 t Bu 2 (CH 2 t Bu)}Rh(μ-Cl) 3 Rh(C 24 H 42 O 2 )] ( 3 ). Both complexes were analyzed by single-crystal X-ray diffraction.

Description: The effect of different deficit-irrigation treatments on the dynamics of mineral nutrients in leaves of peach trees growing under Mediterranean conditions was studied. Treatments consisted of a control, continuous deficit irrigation, regulated deficit irrigation, and partial root drying. The dynamics of nutrients were unchanged by the water deficits, though the amount absorbed was slightly modified. The advantages of deficit-irrigation strategies with regard to water-use efficiency were accompanied by the absence of any harmful effect on leaf mineral nutrition.

Description: This paper reports on the effect of the temperature used to activate kaolinite-based paper industry waste on the hydration products obtained when the activated waste was mixed with a lime solution. After activation at temperatures ranging from 500° to 700°C, clay waste exhibited high pozzolanic activity. Analysis with instrumental techniques such as X-ray diffraction, differential thermal analysis, infrared spectroscopy, and scanning electron microscopy showed that higher temperatures favored the formation of calcium aluminate hydrates, hydrotalcite-like compounds, and strätlingite, while at lower temperatures, CSH gels constituted the majority hydrated phase. According to these findings, reaction kinetics differed substantially from the results obtained at temperatures of 700°–800°C, particularly in terms of phase quantity and timing of appearance. This study shows that metakaolinite can be obtained from clay waste at temperatures of under 700°C. The hydrated phases forming under these conditions are the same as more observed at higher activation temperatures (〉700°C). The main differences found were the sequence of phase formation and the quantity of hydrates detected.

Description: Glass nanocomposites, fabricated using borosilicate glass microspheres and antimony tin oxide (ATO) nanoparticles, were previously reported to have formed segregated networks at the boundaries of the glass particles. This resulted in an electrically conducting composite at low volume fractions (~0.5–0.8 vol%) of ATO nanoparticles. The wide range of electrical response in these borosilicate glass composites containing networks of varying concentration of ATO was examined using impedance spectroscopy. The electrical resistance of these composites varied over a range of around 12 orders of magnitude and exhibited several different types of insulator and conductor behavior. The formation of the ATO network was identified and tracked by scanning electron microscopy images and energy dispersive X-ray spectroscopy (EDS) scans. Detailed impedance spectroscopy analysis using all of the dielectric functions (impedance, permittivity, electric modulus, and admittance) was found to be an excellent method for detecting the development of the network and the effect that processing variables can have on its formation and the overall electrical properties of the nanocomposites.

Description: The sensitivity of solar irradiance at the surface to the variability of aerosol intensive optical properties is investigated for a site (Alta Floresta) in the southern portion of the Amazon basin using detailed comparisons between measured and modeled irradiances. Apart from aerosol intensive optical properties, specifically single scattering albedo (ωoλ) and asymmetry parameter (gλ), which were assumed constant, all other relevant input to the model were prescribed based on observation. For clean conditions, the differences between observed and modeled irradiances were consistent with instrumental uncertainty. For polluted conditions, the agreement was significantly worse, with a root mean square difference three times larger (23.5 Wm−2). Analysis revealed a noteworthy correlation between the irradiance differences (observed minus modeled) and the column water vapor (CWV) for polluted conditions. Positive differences occurred mostly in wet conditions, while the differences became more negative as the atmosphere dried. To explore the hypothesis that the irradiance differences might be linked to the modulation of ωoλ and gλ by humidity, AERONET retrievals of aerosol properties and CWV over the same site were analyzed. The results highlight the potential role of humidity in modifying ωoλ and gλ and suggest that to explain the relationship seen between irradiances differences via aerosols properties the focus has to be on humidity-dependent processes that affect particles chemical composition. Undoubtedly, there is a need to better understand the role of humidity in modifying the properties of smoke aerosols in the southern portion of the Amazon basin.