Comparison of safflower oil extraction kinetics at two characteristic moisture conditions: Statistical analysis of non-linear model parameters

In this study the kinetics of oil extraction from partially dehulled safflower seeds at two moisture conditions (7 and 9% dry basis) was investigated. The extraction essays were performed using a stirred batch system, thermostated at 50 ºC, using n-hexane as solvent. The data obtained were fitted to a modified diffusion model in order to represent the extraction kinetics. The model took into account a washing and a diffusive step. Fitting parameters were compared statistically at both moisture conditions. The oil yield was increased in the extraction time in both cases, although the oil was released at different rates. A comparison of the parameters showed that both the extracted portion in the washing phase and the effective diffusion coefficient were moisture-dependent. The effective diffusivity was 2.81 10-12 and 8.06 10-13 m2 s-1 for a moisture content of 7% and 9%, respectively.Fil: Baumler, Erica Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingenieria Olavarria. Departamento de Ingenieria Quimica; ArgentinaFil: Fernández, María Belén. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingenieria Olavarria. Departamento de Ingenieria Quimica; ArgentinaFil: Nolasco, Susana Maria. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingenieria Olavarria. Departamento de Ingenieria Quimica; ArgentinaFil: Perez, Ethel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingenieria Olavarria. Departamento de Ingenieria Quimica; Argentin

Update on the fluorometric measurement of enzymatic activities for Lysosomal Storage Disorder detection: The example of MPS VI

Lysosomal Storage Disorders (LSD) are rare diseases that as a whole havea combined incidence ranging from 1:1500 to 1:7000 live births. One of suchdiseases is Mucopolysaccharidosis VI (MPS VI), or Maroteaux Lamy Syndrome.MPS VI patients undergo devastating and irreversible skeletal alterations andmultisystemic failure as from early childhood due to reduced Arylsulfatse B(ARSB) enzyme activity.Reaching a final diagnosis is not always a short cut path, but rather a yearslongbattle against uncertainty and unnecessary medical interventions. Ouraim is to contribute from the bench table with different approaches that couldserve as alternatives to pre-existing assays for screening and diagnosing MPSVI and other LSD.The present work is based on our research article authored by Franco etal.1 where we studied the effect of blood-derived hemoglobin, and other bloodcomponents, on the fluorescence of 4-Methylumbelliferone when measuringARSB enzyme activity from dried blood spot (DBS) samples.Our experience indicates that to date there are plenty of differentapproaches for measuring ARSB enzyme activity, although the sample typerequired or the assay in itself often make them more adaptable for either highthroughput screening or small scale diagnostics.As a whole, the fluorometric determinations seem to be the mostaccessible to low budget laboratories with equally valuable performancesas a sophisticated mass spectrometry analysis for this disease. Furthermore,the DBS serves as an attractive sample type for screening the disease in largepopulations.Fil: Franco, Paula Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas ; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Quimica Biologica. Cátedra de Química Biológica Patológica; ArgentinaFil: Adamo, Ana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas ; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Quimica Biologica. Cátedra de Química Biológica Patológica; ArgentinaFil: Mathieu, Patricia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas ; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Quimica Biologica. Cátedra de Química Biológica Patológica; ArgentinaFil: Perez, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas ; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Quimica Biologica. Cátedra de Química Biológica Patológica; ArgentinaFil: Setton, Clara Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas ; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Quimica Biologica. Cátedra de Química Biológica Patológica; ArgentinaFil: Silvestroff, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas ; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Quimica Biologica. Cátedra de Química Biológica Patológica; Argentin

Chemistry: Why the Subject is Difficult?

(Quimica: ?Por que la disciplina es dificil?): Un aspecto comun en todas las culturas es el decreciente numero de alumnos que estudian quimica. ?Cuales son las barreras que evitan que los estudiantes aprendan la quimica? El objetivo de este estudio es explorar la importancia de la filosofia de la quimica y sugerir estrategias que puedan facilitar la comprension conceptual de los estudiantes. Podemos hacer la quimica relevante para ellos y promover su interes, curiosidad y entendimiento al mostrarles que la ciencia es una empresa humana. La estructura corpuscular de la materia da oportunidad de hablar que el cambio de modelos atomicos (Thomson, Rutherford, Bohr, Bohr-Sommerfeld) es una manifestacion de la naturaleza tentativa de las teorias cientificas. Se concluye que la introduccion de algunos elementos de historia y filosofia de la quimica conduce hacia una mejor comprension del progreso cientifico

Stimuli-responsive selection of target DNA sequences by synthetic bZIP peptides

One of the strategies used by nature to regulate gene expression relies on the stimuli controlled combination of DNA-binding proteins. This in turn determines the target-binding site within the genome, and thereby whether a particular gene is activated or repressed. Here we demonstrate how a designed basic region leucine zipper-based peptide can be directed towards two different DNA sequences depending on its dimerization arrangement. While themonomeric peptide is non-functional, a C-terminal metallo-dimer recognizes the natural ATF/CREB-binding site (5'-ATGA cg TCAT-3'), and a N-terminal disulphide dimer binds preferentially to the swapped sequence (5-TCATcg ATGA-30'). As the dimerization mode can be efficiently controlled by appropriate external reagents, it is possible to reversibly drive the peptide to either DNA site in response to such specific inputs. This represents the firstexample of a designed molecule that can bind to more than one specific DNA sequence depending on changes in its environment.Fil: Mosquera, Jesus. Universidad de Santiago de Compostela. Facultad de Quimica. Departamento de Quimica Organica; EspañaFil: Jimenez Balsa, Adrian. Universidad de Santiago de Compostela. Facultad de Quimica. Departamento de Quimica Organica; EspañaFil: Dodero, Veronica Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad de Santiago de Compostela; EspañaFil: Vázquez, M. Eugenio . Universidad de Santiago de Compostela. Facultad de Quimica. Departamento de Quimica Organica; EspañaFil: Mascareñas, José L. . Universidad de Santiago de Compostela. Facultad de Quimica. Departamento de Quimica Organica; Españ

Non-monotonic behavior of weak-polyelectrolytes adsorption on a cationic surface: A Monte Carlo simulation study

In this work, the weak polyelectrolyte (PE) adsorption on a strong cationic surface is studied with constant pH Monte Carlo simulations using a coarse-grained model. When a large number of PE chains is added to the system, the PE adsorbed amount vs pH curve exhibits a non-monotonic behavior, with the appearance of a maximum close to the intrinsic pKa0-value of the PE titratable groups. The apparent pKa-value of the PE chains shows a non-trivial tendency depending on the pH-value and the surface coverage degree. In increasing the pH-value, the small anions that accompany the cationic surface are replaced by PE chains and small cations. For pH>pKa0+1, an evident charge reversion of surface is observed. These results are explained analyzing the interplay between the attractive and repulsion electrostatic interactions between the different components of the system (inter- and intra-charged monomers of PE chains, the strong cationic surface and small ions) and their effects on the PE chain ionization.Fil: Narambuena, Claudio Fabian. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - San Luis. Instituto de Fisica Aplicada "dr. Jorge Andres Zgrablich". Grupo Vinculado Bionanotecnologia y Sistemas Complejos | Universidad Nacional de San Luis. Facultad de Cs.fisico Matematicas y Naturales. Instituto de Fisica Aplicada "dr. Jorge Andres Zgrablich". Grupo Vinculado Bionanotecnologia y Sistemas Complejos. - Universidad Tecnologica Nacional. Facultad Reg.san Rafael. Grupo Vinculado Bionanotecnologia y Sistemas Complejos.; ArgentinaFil: Blanco, Pablo M.. Universidad de Barcelona. Facultad de Quimica. Instituto de Quimica Teorica y Computacional.; EspañaFil: Rodriguez, Adrian. Universidad Tecnológica Nacional. Facultad Reg. Neuquen; ArgentinaFil: Rodríguez, Diego E.. Universidad Tecnológica Nacional. Facultad Reg. Neuquen; ArgentinaFil: Madurga, Sergio. Universidad de Barcelona. Facultad de Quimica. Instituto de Quimica Teorica y Computacional.; EspañaFil: Garcés, José L.. Universidad de Barcelona. Facultad de Quimica. Instituto de Quimica Teorica y Computacional.; EspañaFil: Mas Pujadas, Francesc. Universidad de Barcelona. Facultad de Quimica. Instituto de Quimica Teorica y Computacional.; Españ

Substance and chemical reaction as core concepts in chemistry. A conceptual, historical and pedagogical discussion

En este articulo se lleva a cabo una discusion conceptual, historica y didactica de dos conceptos centrales de la quimica: sustancia y reaccion quimica, en sus aspectos macroscopico y nanoscopico. Se analiza como estos dos conceptos participan en la definicion de Quimica. Tambien se discuten los resultados obtenidos en una revisión de las definiciones presentadas por profesores y por libros de texto. Los autores se abocaron a la busqueda de aportes historicos y conceptuales que resultaran de utilidad para profesores de nivel medio, y que los indujeran a reflexionar sobre ambos conceptos y a llevar adelante modelos adecuados de razonamiento y accion pedagogica

Wood capillarity and deacetylation during eucalyptus alkaline impregnation. Suphidity effects and comparison between transverse directions

The relative ion transport capacity of wood, i.e., the Effective Capillary Cross Sectional Area (ECCSA), is determined in this work based on the analogy with the relation between the electrical conductivities of wood and liquid medium. Wood is treated under different conditions and then the corresponding ECCSAA (effective capillarity under alkali) is estimated from the value obtained in an inert solution at room temperature (ECCSAInert). The difference between radial and tangential ECCSAA-values can be considered similar irrespectively of pH, time, temperature and the presence of sodium sulfide in the treatment liquor. The results show that the degree of removal of native acetyl groups from hardwood O-acetyl-glucuronoxylan is determinant of a physical characteristic, the ECCSAA. A kinetic expression for Eucalyptus wood deacetylation is validated and used to establish the relationship between the acetyl content and ECCSAA in both directions.Fil: Inalbon, Maria Cristina. Universidad Nacional del Litoral. Facultad de Ingenieria Quimica. Instituto de Tecnologia Celulosica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe; ArgentinaFil: Montagna, Pablo. Universidad Nacional del Litoral. Facultad de Ingenieria Quimica. Instituto de Tecnologia Celulosica; ArgentinaFil: Galván, María Verónica. Universidad Nacional del Litoral. Facultad de Ingenieria Quimica. Instituto de Tecnologia Celulosica; ArgentinaFil: Demonte, Luciano. Universidad Nacional del Litoral. Facultad de Ingenieria Quimica. Instituto de Tecnologia Celulosica; ArgentinaFil: Zanuttini, Miguel Angel Mario. Universidad Nacional del Litoral. Facultad de Ingenieria Quimica. Instituto de Tecnologia Celulosica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe; Argentin

Linear algebra and optimization based controller design for trajectory tracking of typical chemical process

This paper presents a new controller design to tracking trajectory of a typical chemical process. The plant model is represented by numerical methods and, from this approach, the control actions for an optimal operation of the system are obtained. Its main advantage is that the condition for the tracking error tends to zero and the calculation of control actions, are obtained solving a system of linear equations. The proofs of convergence to zero of the tracking error are presented. Simulation results show the good performance of the proposed control system.Fil: Serrano, Mario Emanuel. Universidad Nacional de San Juan. Facultad de Ingenieria. Instituto de Ingenieria Quimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Scaglia, Gustavo Juan Eduardo. Universidad Nacional de San Juan. Facultad de Ingenieria. Instituto de Ingenieria Quimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Aballay, P.. Universidad Nacional de San Juan. Facultad de Ingenieria. Instituto de Ingenieria Quimica; ArgentinaFil: Ortiz, O. A.. Universidad Nacional de San Juan. Facultad de Ingenieria. Instituto de Ingenieria Quimica; ArgentinaFil: Mut, Vicente Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Juan. Instituto de Automática; Argentin

Understanding organic materials performance in field-effect transistors

Comunicación oralIn the last years, much of our effort has been devoted to the search and study of new high-mobility semiconductors for organic thin film transistors. The approach used for the materials design has been two-fold: (i) the combination of donor and acceptor moieties in the pi-conjugated skeleton, which allows fine tuning of the frontier molecular orbitals, being this necessary for achieving electron/hole or ambipolar transport and ambient stability; and (ii) rational selection of the type and positioning of specific solubilizing substituents ensuring processability, which is essential to make these materials scalable to industry. However, material processability should be attained minimizing a negative effect on charge transport. Therefore, proper energy levels, planar molecular conformations, close intermolecular pi-pi stacking and adequate thin film crystallinity need to be maintained upon alkyl substitution. In this communication, several examples of molecular and polymeric materials are shown. A rational design, guided by experimental and theoretical evidences, has prompted modifications on their conjugated skeletons, donor/acceptor subunits ratio and/or selection of proper alkyl solubilizing chains, which induce noticeable changes in their electronic performances. The main aim of these studies is the basic understanding of charge transport in organic materials. For this end, we will use Raman spectroscopy and DFT quantum-chemical calculations as important tools for materials characterization.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Structural Studies and Spectroscopic properties of Quinolizidine Alkaloids (+) and (-)-Lupinine in different media

The quinolizidine alkaloids, as numerous species of lupine (Lupinus spp.), are toxic andhave biological effect on the nervous system. Hence, four (+) and (-)- molecular structuresof quinolizidine alkaloid lupinine, named C0, C1a, C1b and C1c have been theoreticallydetermined in gas phase and in aqueous solution by using hybrid B3LYP/6-31G*calculations. The studied properties have evidenced that the most stable C1c form presentthe higher populations in both media while the predicted infrared, Raman, 1H-NMR and 13C-NMR and ultra-visible spectra suggest that probably other forms in lower proportioncould be also present in water, chloroform and benzene solutions, as evidenced by the lowRMSD values observed in the 1H- and 13C-NMR chemical shifts. The C1c form presentsthe lower corrected solvation energy in water while the NBO and AIM studies suggest forthis form a high stability in both media. In addition, the predicted ECD spectra of all (+)and (-)-lupinine forms in methanol solution evidence clearly that the C1b forms is presentin the solution because its spectrum presents a negative Cotton effect as observed in the experimental one.Fil: Ruiz Hidalgo, José. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Iramain, Maximiliano Alberto. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Brandan, Silvia Antonia. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentin