Precipitation and rainwater pH spatial distribution in Bahía Blanca and Tandil, Argentina

The project MAGPlan, funded by the European Commission under the program LIFE+2008, aims to develop and implement an optimal strategy for integral groundwater investigation and efficient remediation of key sources of pollution for the whole inner city area. The first investigations included descriptions of the complex hydro-geological system of the eight aquifers, drilling of monitoring wells and set up of the conceptual contaminant model. A conceptual contaminant model was developed to describe the status quo of the present contaminant distribution, as well as the basic processes controlling contaminant migration within the observed aquifers. This included the characterization of redox conditions and natural chlorinated hydrocarbons degradation processes, as well as age dating, forensic interpretations with respect to the contaminant origin, and determination of radioactive and stable isotopes. Further on, a numerical unsteady groundwater flow and contaminant transport model were developed, which enabled a quantitative description of the mass balance within the project area. The unsteady numerical model provided detection of migration paths in the valley of Stuttgart and identification of key sources of pollution.Fil: Campo, Alicia María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Geografía y Turismo; ArgentinaFil: Zapperi, Paula Andrea. Universidad Nacional del Sur. Departamento de Geografía y Turismo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Picone, Natasha. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Instituto de Geografía, Historia y Ciencias Sociales. Universidad Nacional del Centro de la Provincia de Buenos Aires. Instituto de Geografía, Historia y Ciencias Sociales; Argentin

Striking Dependence of Protein Sweetness on Water Quality: The Role of the Ionic Strength

Sweet proteins are the sweetest natural molecules. This aspect prompted several proposals for their use as food additives, mainly because the amounts to be added to food would be very small and safe for people suffering from sucrose-linked diseases. During studies of sweet proteins as food additives we found that their sweetness is affected by water salinity, while there is no influence on protein’s structure. Parallel tasting of small size sweeteners revealed no influence of the water quality. This result is explained by the interference of ionic strength with the mechanism of action of sweet proteins and provides an experimental validation of the wedge model for the interaction of proteins with the sweet receptor

New insights into the Ar-matrix-isolation FTIR spectroscopy and photochemistry of dichloroacetyl chloride, ClC(O)CHCl2: Influence of O2 and comparison with gas-phase photochemistry

Photolysis products of dichloroacetyl chloride (DCAC) isolated in Ar matrix and in gas phase, in the absence and presence of molecular oxygen, were studied by means of FTIR spectroscopy. The samples were exposed to light of different energy ranges (200–800, 280–320, 350–450 and 400–800 nm). DCAC is photostable when irradiated with light of wavelengths above 400 nm, and gives dichloroketene after photolysis with light between 280–320 and 350–450 nm. Exposure of DCAC to broad-band radiation (200–800 nm) produces dichloroketene as an intermediate photoproduct, and different 1:1 CHCl3:CO molecular complexes after further irradiation. HCl, CO and CHCl3 were detected in gas-phase DCAC photolysis. ClC(O)CCl2CCl2H molecule was also proposed, in a mechanism that involve the insertion of:CCl2 biradical into the C−C bond of DCAC. The photochemical reaction of DCAC with O2 in Ar matrix gives Cl2CO and CO2. The same photoproducts, together with HCl, were observed in the gas-phase photochemical reaction. Additionally, the FTIR spectra of DCAC isolated in solid Ar were fully interpreted in terms of an equilibrium between syn (the H−C bond syn with respect to the C=O bond) and gauche conformers. Some absorptions, which grow as the DCAC:Ar ratio increases, were attributed to dimeric forms. The most stable dimer was predicted by DFT calculations as composed by two DCAC molecules with syn conformations, interacting through two H-bonds in a structure with Ci symmetry.Fil: Tamone, Luciana Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química; ArgentinaFil: Picone, Andrea Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química; ArgentinaFil: Romano, Rosana Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química; Argentin

Sweeter and stronger: Enhancing sweetness and stability of the single chain monellin MNEI through molecular design

Sweet proteins are a family of proteins with no structure or sequence homology, able to elicit a sweet sensation in humans through their interaction with the dimeric T1R2-T1R3 sweet receptor. In particular, monellin and its single chain derivative (MNEI) are among the sweetest proteins known to men. Starting from a careful analysis of the surface electrostatic potentials, we have designed new mutants of MNEI with enhanced sweetness. Then, we have included in the most promising variant the stabilising mutation E23Q, obtaining a construct with enhanced performances, which combines extreme sweetness to high, pH-independent, thermal stability. The resulting mutant, with a sweetness threshold of only 0.28 mg/L (25 nM) is the strongest sweetener known to date. All the new proteins have been produced and purified and the structures of the most powerful mutants have been solved by X-ray crystallography. Docking studies have then confirmed the rationale of their interaction with the human sweet receptor, hinting at a previously unpredicted role of plasticity in said interactio

Color Source for the First Argentinian Flags

In this work, a historical controversy of more than 200 years is settled by the study of the oldest preserved Argentinian flag. The results of the present work reinforce the hypothesis of a number of historians who consider it to be the first flag that was originally hoisted on February 27, 1812, on the banks of the Paraná River. The work consists of a study of the original textile. Through chemical analysis and implementation of different types of analyses, techniques, and spectroscopies such as UV−vis, UV−vis diffuse reflectance spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy, scanning electron microscopy−energy-dispersive X-ray spectroscopy, and resonance Raman, the original characteristics of the flag of Macha were determined. The flag was colored with indigotin from Europe (from Isatis tinctoria) and made of silk; it is white, blue, and white in a horizontal arrangement. It was not treated with tin, and its blue color was subsequently adopted by the Central American Confederation and later by various states of Central America. According to related contemporaneous stories, its preservation was due to the watchfulness of the patriots.Fil: Picone, Andrea Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Romano, Rosana Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Della Védova, Carlos Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; Argentin

Experimental and theoretical investigation on conformational and spectroscopic properties of dimethyl dithiodiglycolate, [CH3OC(O)CH2S]2

Dimethyl dithiodiglycolate (DTG), [CH3OC(O)CH2S]2, was synthetized by complete oxidation of methyl thioglycolate (MTG) with I2, and characterized by gas chromatography coupled with electron-impact mass spectrometry. Fifteen stable conformers were found with the B3LYP/6-31 + G* approximation, with calculated populations at ambient temperature higher than 1%. The IR and Raman spectra of liquid DTG were interpreted for the first time, in terms of equilibrium between four conformers. The UV–visible spectra of DTG in solutions of ethanol, isopropanol and acetonitrile present a low-intensity band around 230 nm, interpreted mainly as arising from n → π* transitions localized at the C[dbnd]O groups, according to the prediction of TD-DFT calculations.Fil: Juncal, Luciana Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica ; ArgentinaFil: Bava, Yanina Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica ; ArgentinaFil: Tamone, Luciana Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica ; ArgentinaFil: Seng, Samantha. Université de Lille 1 Sciences et Technologies; FranciaFil: Tobón, Yeny A.. Université de Lille 1 Sciences et Technologies; FranciaFil: Sobanska, Sophie. Université de Lille 1 Sciences et Technologies; FranciaFil: Picone, Andrea Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica ; ArgentinaFil: Romano, Rosana Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica ; Argentin

Producción de hidrógeno en el hidrotratamiento de etanol utilizando γ-Fe₂O₃ como catalizador: influencia de la temperatura

El previsible agotamiento de los combustibles actualmente empleados y las graves cuestiones de la contaminación atmosférica, obligan a plantear de nuevo cómo obtener la energía necesaria sin emitir compuestos capaces de perturbar la atmósfera que respiramos, y a partir de fuentes renovables. Puesto que puede obtenerse de una diversa gama de fuentes, tales como agua, biomasa, etc, el hidrógeno ofrece, a futuro, un enorme potencial energético. La industria biotecnológica permite obtener etanol a partir de una fuente renovable. La utilización de éste como punto de partida para la obtención de otros productos, tales como hidrógeno, presenta un nuevo desafío para la tecnología química. Dentro de esta línea, el hidrotratamiento de etanol utilizando diversos óxidos de hierro como catalizadores ha recibido especial atención, debido a la elevada actividad de alguno de ellos hacia la producción de hidrógeno como producto principal de reacción. El objetivo del presente trabajo consiste en evaluar la estabilidad de la fase γ del óxido férrico en la reacción mencionada a medida que se incrementa la temperatura, observando la influencia de la misma en la conversión y en la selectividad hacia hidrógeno.Facultad de Ciencias Exacta

Electronically ordered ultrathin Cr2O3 on Pt(1 1 1) in presence of a multidomain graphene intralayer

In the last decade, reducing the dimensionality of materials to few atomic layers thickness has allowed exploring new physical properties and functionalities otherwise absent out of the two dimensional limit. In this regime, interfaces and interlayers play a crucial role. Here, we investigate their influence on the electronic properties and structural quality of ultrathin Cr2O3 on Pt(111), in presence of a multidomain graphene intralayer. Specifically, by combining Low-Energy Electron Diffraction, X-ray Photoelectron Spectroscopy and X-ray Absorption Spectroscopy, we confirm the growth of high-quality ultrathin Cr2O3 on bare Pt, with sharp surface reconstructions, proper stoichiometry and good electronic quality. Once a multidomain graphene intralayer is included at the metal/oxide interface, the Cr2O3 maintained its correct stoichiometry and a comparable electronic quality, even at the very first monolayers, despite the partially lost of the morphological long-range order. These results show how ultrathin Cr2O3 films are slightly affected by the interfacial epitaxial quality from the electronic point of view, making them potential candidates for graphene-integrated heterostructures

Olive oil industry by-products. Effects of a polyphenol-rich extract on the metabolome and response to inflammation in cultured intestinal cell

Over the past years, researchers and food manufacturers have become increasingly interested in olive polyphenols due to the recognition of their biological properties and probable role in the prevention of various diseases such as inflammatory bowel disease. Olive pomace, one of the main by-products of olive oil production, is a potential low-cost, phenol-rich ingredient for the formulation of functional food. In this study, the aqueous extract of olive pomace was characterized and used to supplement human intestinal cell in culture (Caco-2). The effect on the cell metabolome and the anti-inflammatory potential were then evaluated. Modification in the metabolome induced by supplementation clearly evidenced a metabolic shift toward a “glucose saving/accumulation” strategy that could have a role in maintaining anorexigenic hormone secretion and could explain the reported appetite-suppressing effect of the administration of polyphenol-rich food. In both basal and inflamed condition, supplementation significantly reduced the secretion of the main pro-inflammatory cytokine, IL-8. Thus, our data confirm the therapeutic potential of polyphenols, and specifically of olive pomace in intestinal bowel diseases. Although intervention studies are needed to confirm the clinical significance of our findings, the herein reported results pave the road for exploitation of olive pomace in the formulation of new, value-added foods. In addition, the application of a foodomics approach allowed observing a not hypothesized modulation of glucose metabolism

A facile method for in-situ detection of thiabendazole residues in fruit and vegetable peels using Surface-Enhanced Raman Spectroscopy

A flexible Surface-Enhanced Raman Spectroscopy (SERS) substrate based on silver nanoparticles encapsulated in an agar gel has been probed to detect the fungicide thiabendazole (TBZ) reaching a limit of detection (LOD) of 30 ng/cm2. In addition, a simple and sensitive strategy was employed for in-situ detection of TBZ on fruit and vegetable peels. For that purpose, peels of different fruits and vegetables were intentionally contaminated with different amount of TBZ, and the analyte was subsequently extracted within few seconds by gently rubbing the surface with the SERS substrate. The lowest value of TBZ detected on eggplant and green pepper peels was 50 ng/ cm². The values achieved for apple and pear peels were 0.20 μg/cm² and 40 ng/cm², respectively. On the other hand, for tomato and strawberry peels the lowest value achieved was 0.50 μg/cm². The variation in sensitivity can be attributed to differences in the surface properties of the different peels. The above results show that this flexible SERS substrate can be further employed for the detection of contaminants in practical applications for food safety inspection.Centro de Química Inorgánic