Implementación de un programa Lean-six Sigma para la optimización del proceso de producción de probióticos

En este trabajo se desarrolló un plan Lean-Six Sigma de diseño para la optimización del proceso de producción de microorganismos probióticos. Se evaluó el proceso fermentativo de dos cepas bacterianas y una levadura, Lactobacillus rhamnosus (LR), Lactobacillus plantarum (LP) y Saccharomyces boulardii (SB) en biorreactores a escala laboratorio (0.25 L). El crecimiento microbiano se caracterizó en cultivo por lote utilizando medio comercial MRS para LR y LP, y medio comercial YPD para SB. Los tres microorganismos mostraron velocidades específicas de crecimiento (μmáx) similares a las reportadas en la literatura: 0.434 h-1, 0.426 h-1 y 0.545 h-1, respectivamente. A partir del análisis de los resultados de diseños experimentales factoriales y de superficie de respuesta (RSM), se optimizó un medio (MBT) a base de melazas de betabel, azúcar y extracto de té verde (Camellia sinensis) como un substituto económico de los medios comerciales. Posteriormente, se analizó el efecto del medio optimizado sobre las condiciones de crecimiento de los microorganismos; para ello se evaluaron las condiciones de operación del bioproceso en cultivos por lote, continuo y lote alimentado. Tras la optimización, fue posible igualar las concentraciones obtenidas con los medios comerciales (>107 UFC mL-1 para LP, >108 UFC mL-1 para LR y >109 UFC mL-1 para SB). Posteriormente, para la implementación del plan Lean, se evaluó el proceso productivo a escala piloto con la definición de una línea base de producción de 7 kg; con ello se diseñó el mapa de cadena de valor (VSM) del proceso, con el cual se implementó un plan 5S para optimizar el proceso y generar un plan de trabajo estandarizado. Finalmente, se implementó un plan Six Sigma, con el uso de la caracterización del bioproceso para desarrollar las etapas de medición y análisis y generando estrategias de implementación y control a futuro para el bioproceso en etapa piloto.ITESO, A. C

By-Products of Prosperity: Transborder Hazardous Waste Issues Confronting the Maquiladora Industry

The maquiladora program allows Mexican laborers to work in American factories operating in Mexico. This program was specifically designed to generate employment and stimulate industry in Mexico. After a brief discussion of the current status and significance of the maquiladora industry, this Article explains the procedures for the transborder shipment of hazardous waste from Mexico to the United States, a hallmark of the maquiladora program. The authors analyze these procedures in light of anticipated regulatory and economic trends in the region. The analysis includes a discussion of the issue of commingled waste, as well as how NAFTA (North American Free Trade Agreement) will impact Mexico\u27s environmental policies. The authors conclude that the maquiladora program has a prosperous future, despite the hazardous waste issues that threaten the health of the industry

Regolith behavior under asteroid-level gravity conditions: Low-velocity impacts into mm- and cm-sized grain targets

In situ observations of small asteroids show that surfaces covered by boulders and coarse terrain are frequent on such bodies. Regolith grain sizes have distributions on approximately mm and cm scales, and the behavior of such large grains in the very low-gravity environments of small body surfaces dictates their morphology and evolution. In order to support the understanding of natural processes (e.g., the recapturing of impact ejecta) or spacecraft-induced interactions (e.g., the fate of a small lander), we aim to experimentally investigate the response of coarse-grained target surfaces to very-low-speed impacts (below 2 m/s). We present the outcome of 86 low-speed impacts of a cm-sized spherical projectile into a bed of simulated regolith, composed of irregular mm- and cm-sized grains. These impacts were performed under vacuum and microgravity conditions. Our results include measurements for the projectile coefficient of restitution and penetration depth, as well as ejecta production, speed, and mass estimation. We find that impact outcomes include the frequent occurrence of projectile bouncing and tangential rolling on the target surface upon impact. Ejecta is produced for impact speeds higher than about 12 cm/s, and ejecta speeds scale with the projectile to target the grain size ratio and the impact speed. Ejected mass estimations indicate that ejecta is increasingly difficult to produce for increasing grain sizes. Coefficients of restitution of rebounding projectiles do not display a dependency on the target grain size, unlike their maximum penetration depth, which can be scaled with the projectile to target grain size ratio. Finally, we compare our experimental measurements to spacecraft data and numerical work on Hayabusa 2's MASCOT landing on the surface of the asteroid Ryugu

Breaking down the Barrier: Topical Liposomes as Nanocarriers for Drug Delivery into the Posterior Segment of the Eyeball

Topical instillation is the most widely preferred noninvasive route of drug administration to treat diseases affecting the anterior segment of the eye. Nonetheless, the ocular bioavailability for deeper ocular tissues is very low. Different routes of administration, such as intravitreal injections, periocular injections, and systemic administration, have been used to deliver drugs into the posterior segment ocular tissues. However, the presence of blood-retinal barriers (BRBs) makes systemic administration an impractical approach, whereas the drug delivery with the periocular administration route is compromised by ocular static and dynamic barriers. On the other hand, intravitreal injection, the most common and widely recommended route for drug administration to treat posterior ocular diseases, is related to several side effects such as endophthalmitis, hemorrhage, retinal detachment, and poor patient tolerance. Diverse strategies to overcome ocular barriers have been explored for topical drop formulations in order to deliver drugs into the posterior segment ocular tissues. In this chapter, we will review the promising topical nanocarriers for drug delivery into the posterior segment of the eye, emphasizing the use of liposomes for topical ophthalmic formulations targeting the vitreous cavity and the retina

Análisis de viabilidad para la instalación de un sistema fotovoltaico en viviendas

Como parte de la instrumentación de los acuerdos de París, el Gobierno Mexicano impulsa cambios en las políticas de interconexión domésticas de la Comisión Federal de Electricidad. Por su parte, la disminución en los precios de los sistemas fotovoltaicos aumenta la viabilidad de una inversión en esta tecnología. En los siguientes meses y años el país vivirá la transición energética de forma acelerada, y también de forma desordenada. Por un lado, aparecerán cada vez más instaladores improvisados, y por el otro, los usuarios aumentarán sus consumos y probablemente también sus emisiones de gases de efecto invernadero. En esta investigación se propone un método para analizar la viabilidad de instalar paneles fotovoltaicos en vivienda de forma que se mantenga un consumo eléctrico sustentable. Se ilustra la propuesta con una vivienda dentro del área metropolitana de Guadalajara, se discuten los resultados obtenidos y se concluye sobre las variables a considerar

CD38 Exacerbates Focal Cytokine Production, Postischemic Inflammation and Brain Injury after Focal Cerebral Ischemia

BACKGROUND: Converging evidence suggests that inflammatory processes significantly influence brain injury and clinical impairment in ischemic stroke. Although early studies suggested a key role of lymphocytes, recent data has emphasized the orchestrating function of innate immunity, i.e., macrophages and microglia. The bifunctional receptor and ectoenzyme CD38 synthesizes calcium-mobilizing second messengers (e.g., cyclic ADP-ribose), which have been shown to be necessary for activation and migration of myeloid immune cells. Therefore, we investigated the dynamics of CD38 in stroke and the impact of CD38-deficiency on cytokine production, inflammation and cerebral damage in a mouse model of cerebral ischemia-reperfusion. METHODOLOGY/PRINCIPAL FINDINGS: We show that the local expression of the chemokine MCP-1 was attenuated in CD38-deficient mice compared with wildtype mice after focal cerebral ischemia and reperfusion. In contrast, no significant induction of MCP-1 expression was observed in peripheral blood after 6 hours. Flow cytometry analysis revealed less infiltrating macrophages and lymphocytes in the ischemic hemisphere of CD38-deficient mice, whereas the amount of resident microglia was unaltered. An up-regulation of CD38 expression was observed in macrophages and CD8(+) cells after focal cerebral ischemia in wildtype mice, whereas CD38 expression was unchanged in microglia. Finally, we demonstrate that CD38-deficiency decreases the cerebral ischemic injury and the persistent neurological deficit after three days of reperfusion in this murine temporary middle cerebral artery occlusion (tMCAO) model. CONCLUSION/SIGNIFICANCE: CD38 is differentially regulated following stroke and its deficiency attenuates the postischemic chemokine production, the immune cell infiltration and the cerebral injury after temporary ischemia and reperfusion. Therefore CD38 might prove a therapeutic target in ischemic stroke

Fracture Toughness of Vapor Grown Carbon Nanofiber-Reinforced Polyethylene Composites

The impact fracture behavior of a vapor grown carbon nanofiber (VGCNF) reinforced high-density polyethylene (PE) composite was evaluated. The samples consisting of pure PE and composites with 10 wt% and 20 wt% of VGCNFs were prepared by a combination of hot-pressing and extrusion methods. Extrusion was used to produce samples with substantially different shear histories. The fracture behavior of these samples was analyzed using the essential work of fracture (EWF) approach. The results showed an increase of 292% in the essential work of fracture for the loading of 10 wt%. Further increasing fiber loading to 20 wt% caused the essential work of fracture to increase only 193% with respect to the unmodified material. Evaluation of the fracture surface morphology indicated that the fibril frequency and microvoid size within the various fiber loadings depended strongly on processing conditions

Discos interactivos : unidad IV almacenamiento y flujo de la información genética. Proyecto papime EN210804

Se presenta un conjunto de tres CDs para la enseñanza de la Biología Celular a nivel" licenciatura. Los cds acompañan a tres libros de texto de formato pequeño, tamaño esquela. Los CD-ROM, contienen: Unidades didácticas desarrolladas con conceptos esenciales de Biología Celular, vinculados a artículos de apoyo a la docencia (en formato pdf), gráficos, tablas y animaciones de procesos celulares. Imágenes y animaciones en power point y flash (50), que permiten realizar un recorrido visual e interactivo por los conceptos y procesos involucrados en la enseñanza de la Biología Celular. Autevaluaciones, que le permiten al alumno valorar si han adquirido los conocimientos fundamentales de cada unidad. Un glosario, para que el alumno se pueda referir a él en cualquier momento de estudio, para que aclare sus dudas con respecto a los conceptos. Enlaces a sitios confiables en la red, los cuales pueden contener: imágenes en 3D, animaciones, información relevante y ejercicios de cada tema

Evolution of an endofungal Lifestyle: Deductions from the Burkholderia rhizoxinica Genome

<p>Abstract</p> <p>Background</p> <p><it>Burkholderia rhizoxinica </it>is an intracellular symbiont of the phytopathogenic zygomycete <it>Rhizopus microsporus</it>, the causative agent of rice seedling blight. The endosymbiont produces the antimitotic macrolide rhizoxin for its host. It is vertically transmitted within vegetative spores and is essential for spore formation of the fungus. To shed light on the evolution and genetic potential of this model organism, we analysed the whole genome of <it>B. rhizoxinica </it>HKI 0454 - a type strain of endofungal <it>Burkholderia </it>species.</p> <p>Results</p> <p>The genome consists of a structurally conserved chromosome and two plasmids. Compared to free-living <it>Burkholderia </it>species, the genome is smaller in size and harbors less transcriptional regulator genes. Instead, we observed accumulation of transposons over the genome. Prediction of primary metabolic pathways and transporters suggests that endosymbionts consume host metabolites like citrate, but might deliver some amino acids and cofactors to the host. The rhizoxin biosynthesis gene cluster shows evolutionary traces of horizontal gene transfer. Furthermore, we analysed gene clusters coding for nonribosomal peptide synthetases (NRPS). Notably, <it>B. rhizoxinica </it>lacks common genes which are dedicated to quorum sensing systems, but is equipped with a large number of virulence-related factors and putative type III effectors.</p> <p>Conclusions</p> <p><it>B. rhizoxinica </it>is the first endofungal bacterium, whose genome has been sequenced. Here, we present models of evolution, metabolism and tools for host-symbiont interaction of the endofungal bacterium deduced from whole genome analyses. Genome size and structure suggest that <it>B. rhizoxinica </it>is in an early phase of adaptation to the intracellular lifestyle (genome in transition). By analysis of tranporters and metabolic pathways we predict how metabolites might be exchanged between the symbiont and its host. Gene clusters for biosynthesis of secondary metabolites represent novel targets for genomic mining of cryptic natural products. <it>In silico </it>analyses of virulence-associated genes, secreted proteins and effectors might inspire future studies on molecular mechanisms underlying bacterial-fungal interaction.</p