ALBERT

Description: The groundwater hydrochemical behaviour of the Langueyú creek basin (Argentina) has been evaluated through a systematic survey, followed by application of hydrological and chemometric multivariate techniques. Ten physicochemical parameters were determined in groundwater samples collected from 26 wells during 4 sampling campaigns (June, 2010; October, 2010; February, 2011 and June, 2011), originating a tridimensional experimental dataset X . Univariate statistical and graphical hydrochemical tools (contour maps and Piper diagrams) applied to individual campaigns, allowed to reach some preliminary conclusions. However, a best visualization of the aquifer behaviour was achieved by applying Principal Component Analysis (MA-PCA) and N-way PCA procedures, PARAFAC and Tucker3. Results were consistent with two-term models, being Tucker3 [2 2 1] the most adequate, explaining a large amount of the dataset variance (50.7 %) with a low complexity. The first Tucker3 [1 1 1] interaction (38.2% of variance) is related with (i) calcium/magnesium vs. sodium/potassium ion exchange processes; (ii) an increase of ionic concentration and (iii) a decrease of nitrate pollution, all processes along the direction of the groundwater flow. The second [2 2 1] interaction (12.5% of variance), accounts for the predominant role played by conductivity, bicarbonate and magnesium in the dataset. The seasonal variations are closely related to concentration/dilution phenomena originated by the variations of the phreatic levels, although this point will require additional sampling to establish a definitive hydrochemical model. This article is protected by copyright. All rights reserved.

Description: Syntheses for 2-[1-(diarylphosphinoyl)-1-(pyridin-2-yl)methyl]pyridines, ( 8a, b ), and 2-[1-(diarylphosphinoyl)-1,1-bis(methylpyridin-2yl)methyl]pyridines, ( 11a, b ), (Ar = C 6 H 5 and 2-CF 3 C 6 H 4 ), based on substitution of 2-methylpyridine fragments onto the exo methylene carbon atom of 2-[(diaryl)phosphinoylmethyl]pyridine platforms, are described. N-oxidations of 8a, b and 11a, b produced the 2-[1-(diarylphosphinoyl)-1-(1-oxy-pyridin-2yl)methyl]pyridine N -oxides ( 5a, b ) and the 2-[1-(diarylphosphinoyl)-1,1-bis(1-oxy-methylpyridin-2-yl)methyl]pyridines ( 6a, b ), respectively. The “short-arm“ pyridine fragment of 11a, b resists N-oxidation, and the fully oxidized molecules, 2-[1-(diarylphosphinoyl)-1,1-bis(1-oxy-methylpyridin-2-yl)methyl]pyridine N -oxides ( 7a, b ) were not isolated. Molecular mechanics calculations for gas phase 1:1 ligand/lanthanide complexes indicated that 5a should accommodate a tridentate NO(meNO)PO coordination mode with minimal steric strain. In contrast, 7a cannot form tetradentate NO(meNO) 2 PO chelates; however, tridentate binding should be accessible with minimal ligand strain. Coordination complexes of 8a, b , 5a, b , 6a, b and 11a, b with Ln(NO 3 ) 3 salts were isolated and a X-ray crystal structure for [Er( 8a )(NO 3 ) 3 (MeOH) 2 ]·CH 2 Cl 2 , revealed a monodentate Er–O=P interaction. On the other hand, complexes formed by a more symmetrical trifunctional phenylphosphino-bis-2-methylpyridine N, N, P-trioxide ligand, (meNO) 2 PO* , {La[( meNO) 2 PO* )](OTf) 2 (MeOH) 3 (H 2 O) + }(OTf – ) and {Pr[ (meNO) 2 PO* )](OTf)(MeOH) 4 + }(OTf – ) 2 , realized a tridentate coordination mode. Solvent extraction behaviors for Eu III and Am III in nitric acid solutions using 5a, b , 6a, b , Ph 3 PO and the parent bifunctional ligand 2-[(diphenylphosphanyl)methyl]pyridine N, P-dioxide ( 3a ) in 1, 2-dichloroethane were assessed, and 5a, b and 6a, b were found to behave more like Ph 3 PO than 3a .

Description: Questions Are species from different biogeographic groups (mediterranean, alpine and endemic) filtered in different ways by altitude and topography in alpine plant communities? What is the relative performance of these environmental factors at predicting the species diversity of the communities as a whole and of the geographic species groups? Location Picos de Europa, Cantabrian Range (Spain). Methods We sampled the presence and cover of vascular plants in 5-m radius plots on alpine grasslands between 1900 and 2500 m a.s.l. Five GIS-based terrain variables at 15 m × 15 m were used to model species richness and cover per plot using generalized and linear models, and the variation in species composition with redundancy analysis. The same analyses were repeated for the whole data set and for subsets of species from alpine, mediterranean and endemic distributions. Results The influence of altitude and topography on species richness, cover and composition differed for the whole data set and for the geographic species groups. Altitude was the main variable affecting floristic diversity in the communities as a whole, but the separate species groups were more influenced by slope, topographic wetness index and solar radiation. Richness and cover of mediterranean species showed the strongest relationships with topography. Alpine and endemic species showed relationships with topography for species cover and composition, but not for species richness. Conclusions In alpine landscapes, biogeographic deconstruction of the species pool can provide a better understanding of the influence of altitude and topography on local communities than analysis of the entire community alone. Furthermore, the strong influence of local topography on species groups improves our understanding of how alpine species will respond to climate change. We studied the influence of high-resolution altitudinal and topographic variables on species groups with different biogeographic history. Diversity estimates of the geographic groups showed remarkable differences in the relationships with temperature-related factors that were neglected when using data for the whole community. This procedure provides a better understanding of the influence of topography in species assemblages of alpine communities.

Description: The transformation process of clay minerals into pozzolanic products for use as active additives in cement matrixes has been closely studied by both the scientific community and the cement industry. Sourcing these additions from recycled waste products is widely prioritized in environmental policies, because of their associated environmental benefits. This article reports an exhaustive analysis of slate waste in Spain, for its eventual use as an alternative source of pozzolans, based on activated phyllosilicates. The analysis examines the effect of activation conditions on mineralogy and the formation and evolution of the hydrated phases that form during the pozzolanic reaction at 28 days. The results show good pozzolanic activity in the starting slate wastes activated between 800°C and 1100°C of temperature for 2 h of retention, on which basis 1000°C and 2 h were recommended as the more suitable activation conditions for these activated slate wastes (ASW), as total destruction of all phyllosilicates is ensured under those conditions. The hydrated phases formed during the pozzolanic reaction in the ASW/ Ca (\ OH ) 2 system were calcium silicate hydrate gels (CSH), randomly interstratified chlorite (Cl) /smectite with variables containing chlorite/smectite ratios 30% chlorite, 40% chlorite, 50% chlorite, 60% chlorite, respectively, and monosulfoaluminate ( C 3 A · SO 4 Ca ·12 H 2 O ) directly related to the activation process used in this article. All of these findings support the viability of slate waste for use as a pozzolanic addition.

Description: Phytoplankton phenology is primarily affected by physical forcing. However, its quantification is far from being completely understood. Among the physical forcing factors, the Mixed Layer Depth (MLD) is considered to have the strongest impact on phytoplankton dynamics, and consequently, on their phenology. The role of MLD variations in shaping the phytoplankton phenology was explored in the Mediterranean Sea, a basin displaying contrasting phenological regimes. A database of MLD estimations was merged with ocean color chlorophyll concentrations ([Chl] SAT ) to generate concomitant annual MLD and [Chl] SAT cycles. Several indices were calculated to quantitatively analyze these cycles. The relevance of indices summarizing the temporal difference between main characteristics of MLD and [Chl] SAT cycles was emphasized. As previously observed, two dominant phenological regimes co-exist in the Mediterranean Sea. The first is marked by a typical spring bloom, as in temperate regions. The second displays a low seasonality and an absence of an intense [Chl] SAT peak as in subtropical areas. The MLD is shown to play a key role in determining the dominant phenological regime in a given area. Results also show that regions having low seasonality display concomitant MLD and [Chl] SAT maxima, whereas [Chl] SAT peaks are generally observed 30 days after MLD peaks in regions with strongest seasonality. Over the whole basin, [Chl] SAT increase starts one month after the initiation of MLD deepening. Finally, after examining the impact of MLD on light and nutrient availability for phytoplankton, mechanisms were proposed to explain the time-lags between MLD and [Chl] SAT increase and MLD and [Chl] SAT maxima.

Description: ABSTRACT The acute toxicity of cylindrospermopsin (CYN) has been established in rodents, based on diverse intraperitoneal an oral exposure studies and more recently in fish. But no data have been reported in fish after subchronic exposure to cyanobacterial cells containing this cyanotoxin, so far. In this work, tilapia ( Oreochromis niloticus ) were exposed by immersion to lyophilized Aphanizomenon ovalisporum cells added to the aquaria using two concentration levels of CYN (10 or 100 μg CYN L −1 ) and deoxy-cylindrospermopsin (deoxy-CYN) (0.46 or 4.6 μg deoxy-CYN L −1 ), during two different exposure times: 7 or 14 d. This is the first study showing damage in the liver, kidney, hearth, intestines, and gills of tilapia after subchronic exposure to cyanobacterial cells at environmental relevant concentrations. The major histological changes observed were degenerative processes and steatosis in the liver, membranous glomerulopathy in the kidney, myofibrolysis and edema in the heart, necrotic enteritis in the gastrointestinal tract, and hyperemic processes in gill lamellae and microhemorrhages. Moreover, these histopathological findings confirm that the extent of damage is related to the CYN concentration and length of exposure. Results from the morphometric study indicated that the average of nuclear diameter of hepatocytes and cross-sections of proximal and distal convoluted tubules are useful to evaluate the damage induced by CYN in the main targets of toxicity. © 2013 Wiley Periodicals, Inc. Environ Toxicol, 2013.

Description: The percolation threshold in a composite depends on the processing conditions used to fabricate it along with the size and shape of the filler and the matrix. In this study, borosilicate glass microspheres were used as the matrix material, and nanosized antimony tin oxide (ATO) particles were used as the filler. The glass microsphere/ATO composites were fabricated by hot pressing at temperatures in the range between the glass transition temperature and the softening temperature of the glass to control the viscosity. The pressure and temperature applied allowed the ATO to be confined to the spaces between certain glass particles, forming percolating networks at low volume fractions of the ATO. The viscous flow of the glass allowed for the composite to have near full densities, while allowing for the nanoparticle segregation to occur. Even though apparently similar microstructures were made using different heating schedules, the percolation behavior and electrical conductivity showed noticeable differences. The percolation threshold ranged from 0.1 to 2.5 phr (parts per hundred glass) and the change in electrical conductivity was around seven to nine orders of magnitude. The differences were attributed to the interaction of the segregated ATO particles with one another. The electrical properties were examined using ac impedance spectroscopy along with current atomic force microscopy (C-AFM), which allowed for valuable insights in the structure–property–processing relationships in these materials.

Description: Olfactory ensheathing cells (OECs) are known to be capable of continuous neurogenesis throughout lifetime and are a source of multiple trophic factors important in central nervous system regeneration. B104 neuroblastoma cells are recognized to induce differentiation of neural stem cells into oligodendrocyte precursor cells. Therefore, the aim of this study was to verify if conditioned medium (CM) obtained from OECs or B104 cells was capable of inducing differentiation of adipose tissue-derived mesenchymal stem cells (AT-MSCs) to a neuronal phenotype. In order to, immunocytochemical procedures and flow cytometry analysis were used and some neural markers, as nestin, protein gene product 9.5 (PGP 9.5), microtubule-associated protein 2 (MAP2), glial fibrillary acidic protein (GFAP), and neuron cell surface antigen (A2B5) were examined 24 hours and 7 days after the treatment. The results showed that both OECs- or B104-CM treated AT-MSCs express markers of progenitor and mature neurons (nestin, PGP 9.5 and MAP2) in time-dependent manner, display morphological features resembling neuronal cells, and result negative for GFAP and A2B5, astrocyte and oligodendrocyte markers, respectively. This study demonstrated that AT-MSCs can be influenced by the environment, indicating that these cells can respond to environmental cues also versus a neuronal phenotype. J. Cell. Physiol. © 2013 Wiley Periodicals, Inc.

Description: ABSTRACT Human exposure to persistent organic pollutants (POPs) is a certainty, even to long banned pesticides like o,p ′-dichlorodiphenyltrichloroethane ( o,p ′-DDT), and its metabolites p,p ′-dichlorodiphenyldichloroethylene ( p,p ′-DDE), and p,p ′-dichlorodiphenyldichloroethane ( p,p ′-DDD). POPs are known to be particularly toxic and have been associated with endocrine-disrupting effects in several mammals, including humans even at very low doses. As environmental estrogens, they could play a critical role in carcinogenesis, such as in breast cancer. With the purpose of evaluating their effect on breast cancer biology, o,p ′-DDT, p,p ′-DDE, and p,p ′-DDD (50–1000 nM) were tested on two human breast adenocarcinoma cell lines: MCF-7 expressing estrogen receptor (ER) α and MDA-MB-231 negative for ERα, regarding cell proliferation and viability in addition to their invasive potential. Cell proliferation and viability were not equally affected by these compounds. In MCF-7 cells, the compounds were able to decrease cell proliferation and viability. On the other hand, no evident response was observed in treated MDA-MB-231 cells. Concerning the invasive potential, the less invasive cell line, MCF-7, had its invasion potential significantly induced, while the more invasive cell line MDA-MB-231, had its invasion potential dramatically reduced in the presence of the tested compounds. Altogether, the results showed that these compounds were able to modulate several cancer-related processes, namely in breast cancer cell lines, and underline the relevance of POP exposure to the risk of cancer development and progression, unraveling distinct pathways of action of these compounds on tumor cell biology. © 2013 Wiley Periodicals, Inc. Environ Toxicol, 2013.

Description: Devonian sediments of the Malaguide Complex potentially could include the Frasnian-Famennian boundary, one of the five greatest Phanerozoic biotic crisis. Conodont biofacies and microfacies of carbonate clasts from a pebbly mudstone underlying Tournaisian radiolarites allows identification, for the first time in the Malaguide Complex, of Devonian shallow marine environments laterally grading to deeper realms. The clasts yielded Frasnian conodont associations of the falsiovalis to rhenana biozones, with six biofacies that reveal different environmental conditions in their source areas. Source sediments were dismantled and redeposited within the pebbly mudstone, whose origin is tentatively related to one of the events that are associated worldwide with the Frasnian-Famennian crisis. The latter is recorded, in two equivalent Malaguide pelagic successions, by stratigraphic discontinuities, and it was, probably, tectonically and/or eustatically controlled, as in other Alpine-Mediterranean Paleotethyan margins. This article is protected by copyright. All rights reserved.