Extracción de pectinas a partir de los subproductos del beneficio del cacao

En este estudio se evaluó la posibilidad de obtener pectinas a partir de los subproductos del proceso del beneficio del cacao. Los experimentos se llevaron a cabo en el laboratorio de desarrollo de productos del departamento de ingeniería de procesos de la Universidad EAFIT.53 p.Contenido parcial: Cacao -- Pectina -- Materiales y equipos -- Procedimiento del desarrollo experimental -- Caracterización y comparación de las pectinas obtenidas con la pectina comercial -- Costos de materia prima

Actin- and myosin-dependent vesicle loading of presynaptic docking sites prior to exocytosis.

Variance analysis of postsynaptic current amplitudes suggests the presence of distinct docking sites (also called release sites) where vesicles pause before exocytosis. Docked vesicles participate in the readily releasable pool (RRP), but the relation between docking site number and RRP size remains unclear. It is also unclear whether all vesicles of the RRP are equally release competent, and what cellular mechanisms underlie RRP renewal. We address here these questions at single glutamatergic synapses, counting released vesicles using deconvolution. We find a remarkably low variance of cumulative vesicle counts during action potential trains. This, combined with Monte Carlo simulations, indicates that vesicles transit through two successive states before exocytosis, so that the RRP is up to 2-fold higher than the docking site number. The transition to the second state has a very rapid rate constant, and is specifically inhibited by latrunculin B and blebbistatin, suggesting the involvement of actin and myosin

Carta persuasiva al señor don Ignacio de Escandón

El comandante general de guerra Don Ignancio de Escandón con el respeto, que debe, dice: Que en todas las naciones políticas ha sido universal empeño conservar las memorias de sus sabios, no sólo por este un homenaje debido a su mérito, sino porque la patria se ilustra con sus literatos, y por que el número de estos acredita de cultas las regiones. Por otra parte nada más conveniente al aliento de la juventud en la carrera de las letras, que le recuerdo de los sabios patricios, cuyo ejemplo obra con más eficacia, porque se toca con mayor inmediatiación.CuencaAño 2, número 14 (julio 31 de 1891

Osteopoiquilosis y síndrome de Buschke-Ollendörf: a propósito de un caso

Presentamos una paciente de 22 años que tras estudios radiológicos rutinarios, muestra una displasia ósea condensante, completamente asintomática e inócua, que afectaba principalmente pelvis y extremidades distales, mientras que las costillas, cráneo y columna dorsolumbar estaban indemnes. Asimismo, aparecen nevus elásticos y fibromas en la piel. Esta entidad no puede confundirse con un carcinoma metastásico esclerosante, esclerosis tuberosa u otras displasias como la melorreostosis.A female patient, 22 years oíd, showing characteristic sclerotic bone images on radiographic examinations is reported. The main locations were on the distal limbs and pelvis. She has also elastic nevi as freckles in the skin. This entity was not stablished as inhered process. The differential diagnosis lies between sclerotic metastasis, neurofibromatosis (Von Recklinghausen), Bourneville disease and other displastyc lesions

Sugar, acid and furfural quantification in a sulphite pulp mill: Feedstock, product and hydrolysate analysis by HPLC/RID

Waste from pulp and paper mills consist of sugar-rich fractions comprising hemicellulose derivatives and cellulose by-products. A complete characterisation of the waste streams is necessary to study the possibilities of an existing mill. In this work, four chromatographic methods have been developed to obtain the most suitable chromatographic method conditions for measuring woody feedstocks, lignocellulosic hydrolysates and cellulose pulp in sulphite pulping processes. The analysis of major and minor monosaccharides, aliphatic carboxylic acids and furfurals has been optimised. An important drawback of the spent liquors generated after sulphite pulping is their acidic nature, high viscosity and adhesive properties that interfere in the column lifetime. This work recommends both a CHO-782Pb column for the sugar analysis and an SH-1011 resin-based cross-linked gel column to separate low-molecular-weight chain acids, alcohols and furfurals. Such columns resulted in a good separation with long lifetime, wide pH operating range and low fouling issues.The authors gratefully acknowledge the financial support of the European Union for this research by the BRIGIT “New tailor-made biopolymers produced from lignocellulosic sugars waste for highly demanding fire-resistant applications” research project under the seventh framework program www.brigit-project.eu

High Vcmax, Jmax and photosynthetic rates of Sonoran Desert species : using nitrogen and specific leaf area traits as predictors in biochemical models

Dryland ecosystems largely control the inter-annual variability of the global carbon cycle. Unfortunately, there is a paucity of data on key biochemical parameters, such as maximum carboxylation velocity (Vcmax25) and electron transport rate (Jmax25), from species in these ecosystems which limits our capacity to model photosynthesis across ecological scales. We studied six dominant C3 shrub and tree species from the Sonoran Desert with different leaf traits and phenological strategies. We characterized Vcmax25 and Jmax25 for each species and assessed which traits or trait combinations were the best predictors of these parameters for biochemical models of photosynthesis. All species had high values of Vcmax25 and Jmax25, mostly explained by high leaf nitrogen content (Narea) and high nitrogen allocation to photosynthetic enzymes comparable to those reported for herbs and crop species but higher than those of shrubs and other functional types in world databases. We found that the high values of Vcmax25 and Jmax25, by increasing rates of photosynthetic reactions, enhance photosynthetic water and nitrogen-use efficiencies and may favor carbon gain under typical conditions in drylands. Our findings improve the parameterization of photosynthesis models, and provide novel implications to common findings of high Narea in dryland species