Luminescent quantum clusters of gold in transferrin family protein, lactoferrin exhibiting FRET

We report the synthesis of highly luminescent, water soluble quantum clusters (QCs) of gold, which are stabilized by an iron binding transferrin family protein, lactoferrin (Lf). The synthesized AuQC@Lf clusters were characterized using UV-Visible spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), photoluminescence (PL), matrix assisted laser desorption ionization mass spectrometry (MALDI-MS), FTIR spectroscopy and circular dichroism (CD) spectroscopy along with picosecond-resolved lifetime measurements. Detailed investigations with FTIR and CD spectroscopy have revealed changes in the secondary structure of the protein in the cluster. We have also studied F?rster resonance energy transfer (FRET) occurring between the protein and the cluster. The ability of the clusters to sense cupric ions selectively at ppm concentrations was tested. The stability of clusters in widely varying pH conditions and their continued luminescence make it feasible for them to be used for intracellular imaging and molecular delivery, particularly in view of Lf protection.     

Synthesis and Biological Evaluation of 9‐Oxo‐9H‐indeno[1,2‐b]pyrazine‐2,3‐dicarbonitrile Analogues as Potential Inhibitors of Deubiquitinating Enzymes

High‐throughput screening highlighted 9‐oxo‐9H‐indeno[1,2‐b]pyrazine‐2,3‐dicarbonitrile ( 1 ) as an active inhibitor of ubiquitin‐specific proteases (USPs), a family of hydrolytic enzymes involved in the removal of ubiquitin from protein substrates. The chemical behavior of compound 1 was examined. Moreover, the synthesis and in vitro evaluation of new compounds, analogues of 1 , led to the identification of potent and selective inhibitors of the deubiquitinating enzyme USP8.     

Quantification of the total amount of artemisinin in leaf samples by thin layer chromatography

Artemisinin is a natural molecule highly active against malaria. At present, the extraction of this molecule from the leaves of Artemisia annua L. remains the only viable method to produce cheaply large quantities of artemisinin. Agronomic research on this plant species aims to improve agricultural yields, to decrease production costs and to ensure a steady global supply of artemisinin. These research activities require an easy, rapid, low cost, and reliable analytical technique to quantify the artemisinin content in the leaves. Thin layer chromatography (TLC) methods to quantify this molecule have already been published. However, this method does not allow the quantification of the total artemisinin content in the leaves. In order to validate the TLC method, results obtained with this method were related to results for the same samples obtained by accelerated solvent extraction and high pressure liquid chromatography with an evaporative light scattering detector (ASE-HPLC-ELSD). Using the Nernst partition law, a corrective factor of 1.21 is suggested to enable information about the true total amount of artemisinin in leaf samples to be obtained within a range of 0.25 to 3%. In conclusion, this study proposes for the first time a corrective factor in order to quantify the total artemisinin content of A. annua leaves with TLC.     

An efficient entry to planar chiral organometallic complexes via Pd-catalyzed asymmetric hydrogenolysis

Planar chiral chromium- and ruthenium-based arene complexes were prepared with high levels of enantioselectivity via a Pd-catalyzed asymmetric hydrogenolysis reaction using a bulky chiral phosphoramidite ligand. Key elements for the efficiency of the process are the use of DABCO as borane-trapping reagent as well as substantial kinetic resolution, which was found to enhance the stereochemical outcome of the reaction.     

Chemometric modeling and prediction of trihalomethane formation in Barcelona's water works plant

Formation and occurrence of trihalomethanes (CHCl3, CHBr3, CHCl2Br, and CHBr2Cl) are investigated in water chlorination disinfection processes in the Barcelona's water works plant (WWP). Twenty-three WWP variables were measured and investigated for correlation with trihalomethane formation. Multivariate statistical methods including principal component analysis (PCA), multilinear regression (MLR), stepwise MLR (SWR), principal component regression (PCR) and partial least squares regression (PLSR) have been used and compared to model and predict the complex behavior observed for the measured trihalomethane concentrations. The results, obtained by PCA as well as the evaluation of the statistical significance of the coefficients in the linear regression vectors, revealed that the most important WWP variables for trihalomethane formation were: water temperature, total organic carbon, added chlorine concentrations, UV absorbance and turbidity at different sites of the WWP, as well as other variables like wells supply flow levels and carbon filters age. Overall, MLR and PLSR methods performed the best and gave similar good predictive properties. Best results were obtained for the total sum of trihalomethane concentrations, TTHM, with average modeling and prediction relative errors of 12% and 16%, respectively. Among the individual trihalomethanes, the concentrations of CHBr3 were the worst predicted ones with average modeling and prediction relative errors between 21-25% and 29-31%, respectively, followed by CHCl2Br with 23-26% and 25-27%. Better predictions were obtained for the concentrations of CHBr2Cl with relative modeling and prediction errors varying between 14-17% and 21%, and for the concentrations of CHCl3 with 21-24% and 23-25% errors, respectively.     

Effects of particulate and soluble substrates on microfauna populations and treatment efficiency in activated sludge systems

To determine the effects of particulate and soluble compounds on microfauna populations and treatment efficiency in activated sludge systems, two experimental wastewater treatment plants were set up and evaluated for a period of five months. The plants were fed with pre-flocculated domestic sewage enriched with starch or glucose as model substrates of particulate and soluble organic matter, respectively. It was observed that the starch-enriched system presented lower abundance of filamentous bacteria that turned into a better sludge sedimentation. Mean sludge volume index (SVI) values for the starch and glucose-enriched systems were 54+/-24 and 885+/-845 mL g(-1), respectively. Although no differences in organic matter removal were detected between the systems, nitrification and denitrification were higher in the starch-enriched system, which is likely to have been the result of its more compact flocs. The mean ammonia-N effluent concentrations for the starch and glucose-enriched systems were 4.7+/-5.7 and 16.2+/-9.7 mg L(-1), respectively, whereas the nitrate-N concentrations were 20.1+/-10.8 and 30.8+/-12.2 mg L(-1), respectively. Concerning microfauna analysis, ciliated protozoa specifically, attached ciliates were the dominant microfauna group in both treatment systems, whereas metazoa, particularly Lecanidae rotifera, were more abundant in the starch-enriched system. Lecanidae rotifera abundances above 400 ind mL(-1) reduced the mean floc area from 60 to 20mm(2) without affecting sludge settleability in the starch-enriched system. Finally, the reduction in floc area caused by metazoa feeding led to effluents of lower nitrogen quality, although no differences in sludge production were detected.     

Intense winter atmospheric pollution episodes affecting the Western Mediterranean

The geographic location of the Western Mediterranean Basin and its peculiar topography, the climatic conditions and the intense anthropogenic and natural emissions of atmospheric pollutants are key factors necessary to interpret the atmospheric aerosol phenomenology over this area. During the cold season it is common to have severe atmospheric particulate matter (PM) pollution episodes (of an anthropogenic origin) affecting this region, not only in the urban and industrial areas but also in the regional and rural sites. During these episodes, the midday hourly PM₁ levels at regional background sites are in many cases higher than those at urban areas. Around 10% of the days under winter anticyclonic conditions registered similar PM₁ levels at the regional background than at the urban area and, sporadically the daily PM₁ levels at the regional background sites may exceed those at urban sites. Furthermore, the very high hourly PM₁ levels measured at regional background sites during these episodes are not regularly attained in the closest urban areas, which leads to the hypothesis that an important formation of secondary aerosols occurs during the transport of the polluted air masses towards the elevated rural sites.The interpretation of the variability of PM levels and composition (2002-2008) at one urban site (Barcelona) and at one regional background site (Montseny) allows us to illustrate the phenomenology of these scenarios, to quantify the mean annual contributions to the PM levels and to identify their main tracers. Ammonium nitrate appears to be the most abundant compound during these scenarios, although organic species and trace metals also increase markedly. Owing to the intensity, composition and recurrence of these atmospheric pollution episodes, important health, climatic and ecological implications may be derived.     

Complex nanominerals and ultrafine particles assemblages in phosphogypsum of the fertilizer industry and implications on human exposure

Phosphogypsum (CaSO₄·2H₂O), a by-product of phosphate-rock processing, contains high amounts of impurities such P₂O₅, F, radioactive elements, organic substances, secondary nanominerals, and ultrafine particles (UFP) enriched in metals and metalloids. In this study, we examine phosphogypsum (PG) collected from abandoned fertilizer industry facility in south Brazil (Santa Catarina state). The fragile nature of nanominerals and UFP assemblages from fertilizer industry systems required novel techniques and experimental approaches. The investigation of the geochemistry of complex nanominerals and UFP assemblages was a prerequisite to accurately assess the environmental and human health risks of contaminants and cost-effective chemical and biogeological remediation strategies. Particular emphasis was placed on the study and characterization of the complex mixed nanominerals and UFP containing potentially toxic elements. Nanometer-sized phases in PG were characterized using energy-dispersive X-ray spectrometer (EDS), field-emission scanning electron microscope (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM) images. The chemical composition and possible correlations with morphology of nanominerals and UFP, as well as aspects of nanominerals and UFP, are discussed in the context of human health exposure, as well as in relation to management of the nanominerals and UFP in PG environments.     

An Efficient Palladium‐NHC (NHC=N‐Heterocyclic Carbene) and Aryl Amination Pre‐Catalyst: [Pd(IPr*)(cinnamyl)Cl]

The well‐defined [Pd(IPr*)(cinnamyl)Cl] complex is reported as one of the best N‐heterocyclic carbene (NHC)‐based pre‐catalysts for the Buchwald–Hartwig amination reaction. This catalytic system displays high efficiency for the coupling of numerous (hetero)aryl chlorides, with a wide range of amines, at room temperature or at extremely low catalyst loading (as low as 0.025 mol%).