Evaluación económica del proceso de recuperación de proteínas de las harinas extraídas de la soja argentina

Las harinas de extrusión-prensado de soja (EE) son el subproducto del proceso de extracción de aceite de soja utilizado habitualmente por pequeñas y medianas empresas argentinas. En este estudio se evaluó la viabilidad económica de producción de concentrados proteicos a partir de estas harinas. Se consideró una capacidad de procesamiento de 18 ton/día de harinas EE, equivalente a una producción 1.500 ton/año de concentrado proteico. La metodología propuesta consideró un proceso de cambio de pH, 3 ciclos de extracción alcalina a 60 ºC seguidos de precipitación isoeléctrica a baja temperatura utilizando HCl, resultando un producto final con contenido proteico del 75 % (bs) y una productividad de 0,28 kg de producto/kg de harinas EE. Para analizar un caso práctico, la producción propuesta se llevaría a cabo como ampliación de una planta típica de extrusión-prensado de soja de tamaño medio. Como resultado, la inversión de capital necesaria se estimó en 2,7 millones de dólares. Se calcularon otros indicadores de rendimiento financiero, como valor actual neto y tasa interna de rendimiento, y se concluyó que la propuesta de obtención de un concentrado proteico de soja era económicamente viable a escala industrial si los precios de venta son superiores a 2.267 US$/tonelada.Soybean extruded-expelled (EE) meals are the byproduct of the soybean oil extraction process commonly used by small and medium-sized Argentinean companies. In this study, the economic feasibility of protein concentrate production from soybean EE meals was evaluated. A processing daily capacity of 18 ton of EE meals was considered, resulting in an annual production of 1,500 ton of protein concentrate. The proposed methodology considered a pH change process consisting of 3 cycles of alkaline extraction at 60 ºC followed by isoelectric precipitation at low temperature using hydrochloric acid, which resulted in a final product with a protein content of 75$2.7 million. Additional financial performance indicators were computed, including net present value and internal rate of return, and it was concluded that the proposal to obtain a protein concentrate from soybean EE meals was economically viable on an industrial scale if sale prices are above 2,267 US$/ton.Fil: Accoroni, C.. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Godoy, E.. Universidad Tecnológica Nacional. Facultad Regional Rosario; ArgentinaFil: Reinheimer, Maria Agustina. Universidad del Centro Educativo Latinoamericano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentin

Fabrication and Characterization of Fully Inkjet Printed Capacitors Based on Ceramic/Polymer Composite Dielectrics on Flexible Substrates

The preparation of fully inkjet printed capacitors containing ceramic/polymer composites as the dielectric material is presented. Therefore, ceramic/polymer composite inks were developed, which allow a fast one-step fabrication of the composite thick films. Ba0.6Sr0.4TiO3 (BST) is used as the ceramic component and poly(methyl methacrylate) (PMMA) as the polymer. The use of such composites allows printing on flexible substrates. Furthermore, it results in improved values for the permittivity compared to pure polymers. Three composite inks with varying ratio of BST to PMMA were used for the fabrication of composite thick films consisting of 33, 50 and 66 vol% BST, respectively. All inks lead to homogeneous structures with precise transitions between the different layers in the capacitors. Besides the microstructures of the printed thick films, the dielectric properties were characterized by impedance spectroscopy over a frequency range of 100 Hz to 200 kHz. In addition, the influence of a larger ceramic particle size was investigated, to raise permittivity. The printed capacitors exhibited dielectric constants of 20 up to 55 at 1 kHz. Finally, the experimental results were compared to different theoretical models and their suitability for the prediction of εcomposite was assessed

Functional properties of exopolysaccharide (EPS) extract from Lactobacillus fermentum Lf2 and its impact when combined with Bifidobacterium animalis INL1 in yoghurt

The roles of an exopolysaccharide (EPS) extract from Lactobacillus fermentum Lf2 were studied individually or combined with a probiotic strain, Bifidobacterium animalis subsp. lactis INL1. EPS in its purified form caused an increase in the levels of cytokine TNF-α; both purified and crude EPS produced an increase in the regulatory cytokine IL-10. BALB/c mice received yoghurt with no additives (Y), with EPS (YE), with bifidobacteria (YB), or both (YEB) for 25 days. Only the YE group presented significantly increased concentrations of total short chain fatty acids (p < 0.05) including acetic and butyric acids; the levels of the C. coccoides cluster also rose over time (p < 0.05) for this group. A possible bifidogenic role was observed with the YEB group, reflected in the increasing levels of the genus Bifidobacterium along time (p < 0.05); this was not observed when the probiotic was administered solely (YB group)

Nonlinear response of dense colloidal suspensions under oscillatory shear: Mode-coupling theory and FT-rheology experiments

Using a combination of theory, experiment and simulation we investigate the nonlinear response of dense colloidal suspensions to large amplitude oscillatory shear flow. The time-dependent stress response is calculated using a recently developed schematic mode-coupling-type theory describing colloidal suspensions under externally applied flow. For finite strain amplitudes the theory generates a nonlinear response, characterized by significant higher harmonic contributions. An important feature of the theory is the prediction of an ideal glass transition at sufficiently strong coupling, which is accompanied by the discontinuous appearance of a dynamic yield stress. For the oscillatory shear flow under consideration we find that the yield stress plays an important role in determining the non linearity of the time-dependent stress response. Our theoretical findings are strongly supported by both large amplitude oscillatory (LAOS) experiments (with FT-rheology analysis) on suspensions of thermosensitive core-shell particles dispersed in water and Brownian dynamics simulations performed on a two-dimensional binary hard-disc mixture. In particular, theory predicts nontrivial values of the exponents governing the final decay of the storage and loss moduli as a function of strain amplitude which are in excellent agreement with both simulation and experiment. A consistent set of parameters in the presented schematic model achieves to jointly describe linear moduli, nonlinear flow curves and large amplitude oscillatory spectroscopy

Copper (I) SNS Pincer Complexes: Impact of Ligand Design and Solvent Coordination on Conformer Interconversion from Spectroscopic and Computational Studies

The syntheses and detailed characterizations (X-ray crystallography, NMR spectroscopy, cyclic voltammetry, infrared spectroscopy, electrospray mass spectrometry, and elemental analyses) of two new Cu(I) pincer complexes are reported. The pincer ligand coordinates through one nitrogen and two sulfur donor atoms and is based on bis-imidazole or bis-triazole precursors. These tridentate SNS ligands incorporate pyridine and thione-substituted imidazole or triazole functionalities with connecting methylene units that provide flexibility to the ligand backbone and enable high bite-angle binding. Variable temperature 1H NMR analysis of these complexes and of a similar zinc(II) SNS system shows that all are fluxional in solution and permits the determination of ΔGexp‡ and ΔSexp‡. DFT calculations are used to model the fluxionality of these complexes and indicate that a coordinating solvent molecule can promote hemilability of the SNS ligand by lowering the energy barrier involved in the partial rotation of the methylene units

Draft genome sequence of Lactobacillus fermentum Lf2, an exopolysaccharide-producing strain isolated from Argentine cheese

Lactobacillus fermentum Lf2, an Argentine cheese isolate, can produce high concentrations of exopolysaccharides (EPS). These EPS were shown to improve the texture and rheology of yogurt, as well as to play a protective role in mice exposed to Salmonella enterica serovar Typhimurium. Three gene clusters potentially involved in EPS production were identified in different locations of the L. fermentum Lf2 genome

Macro-Climatic Distribution Limits Show Both Niche Expansion and Niche Specialization among C4 Panicoids

Grasses are ancestrally tropical understory species whose current dominance in warm open habitats is linked to the evolution of C4 photosynthesis. C4 grasses maintain high rates of photosynthesis in warm and water stressed environments, and the syndrome is considered to induce niche shifts into these habitats while adaptation to cold ones may be compromised. Global biogeographic analyses of C4 grasses have, however, concentrated on diversity patterns, while paying little attention to distributional limits. Using phylogenetic contrast analyses, we compared macro-climatic distribution limits among ~1300 grasses from the subfamily Panicoideae, which includes 4/5 of the known photosynthetic transitions in grasses. We explored whether evolution of C4 photosynthesis correlates with niche expansions, niche changes, or stasis at subfamily level and within the two tribes Paniceae and Paspaleae. We compared the climatic extremes of growing season temperatures, aridity, and mean temperatures of the coldest months. We found support for all the known biogeographic distribution patterns of C4 species, these patterns were, however, formed both by niche expansion and niche changes. The only ubiquitous response to a change in the photosynthetic pathway within Panicoideae was a niche expansion of the C4 species into regions with higher growing season temperatures, but without a withdrawal from the inherited climate niche. Other patterns varied among the tribes, as macro-climatic niche evolution in the American tribe Paspaleae differed from the pattern supported in the globally distributed tribe Paniceae and at family level.Fil: Aagesen, Lone. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Biganzoli, Fernando. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bena, María Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Godoy Bürki, Ana Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Reinheimer, Renata. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentin

Modern optical astronomy: technology and impact of interferometry

The present `state of the art' and the path to future progress in high spatial resolution imaging interferometry is reviewed. The review begins with a treatment of the fundamentals of stellar optical interferometry, the origin, properties, optical effects of turbulence in the Earth's atmosphere, the passive methods that are applied on a single telescope to overcome atmospheric image degradation such as speckle interferometry, and various other techniques. These topics include differential speckle interferometry, speckle spectroscopy and polarimetry, phase diversity, wavefront shearing interferometry, phase-closure methods, dark speckle imaging, as well as the limitations imposed by the detectors on the performance of speckle imaging. A brief account is given of the technological innovation of adaptive-optics (AO) to compensate such atmospheric effects on the image in real time. A major advancement involves the transition from single-aperture to the dilute-aperture interferometry using multiple telescopes. Therefore, the review deals with recent developments involving ground-based, and space-based optical arrays. Emphasis is placed on the problems specific to delay-lines, beam recombination, polarization, dispersion, fringe-tracking, bootstrapping, coherencing and cophasing, and recovery of the visibility functions. The role of AO in enhancing visibilities is also discussed. The applications of interferometry, such as imaging, astrometry, and nulling are described. The mathematical intricacies of the various `post-detection' image-processing techniques are examined critically. The review concludes with a discussion of the astrophysical importance and the perspectives of interferometry.Comment: 65 pages LaTeX file including 23 figures. Reviews of Modern Physics, 2002, to appear in April issu