1,273 research outputs found

    Self-Assembly Behavior of Amphiphilic Janus Dendrimers in Water: A Combined Experimental and Coarse-Grained Molecular Dynamics Simulation Approach

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    Indexación: Scopus.Acknowledgments: M.E.E.G. thank the Ph. D. scholarship (251115) from CONACyT. The authors would like to thank: Luis Elizalde-Herrera (CIQA) for his help running the NMR spectra; Gloria Macedo-Raygoza and Miguel J. Beltrán-García (UAG), for their help in the measuring of MALDI-TOF mass spectra; and Maricela Rodríguez-Nieto and Jorge Luis Menchaca (UANL), for their help with the AFM measurements. FDGN thanks to the USA Air Force Office of Scientific Research Awards.Amphiphilic Janus dendrimers (JDs) are repetitively branched molecules with hydrophilic and hydrophobic components that self-assemble in water to form a variety of morphologies, including vesicles analogous to liposomes with potential pharmaceutical and medical application. To date, the self-assembly of JDs has not been fully investigated thus it is important to gain insight into its mechanism and dependence on JDs’ molecular structure. In this study, the aggregation behavior in water of a second-generation bis-MPA JD was evaluated using experimental and computational methods. Dispersions of JDs in water were carried out using the thin-film hydration and ethanol injection methods. Resulting assemblies were characterized by dynamic light scattering, confocal microscopy, and atomic force microscopy. Furthermore, a coarse-grained molecular dynamics (CG-MD) simulation was performed to study the mechanism of JDs aggregation. The obtaining of assemblies in water with no interdigitated bilayers was confirmed by the experimental characterization and CG-MD simulation. Assemblies with dendrimersome characteristics were obtained using the ethanol injection method. The results of this study establish a relationship between the molecular structure of the JD and the properties of its aggregates in water. Thus, our findings could be relevant for the design of novel JDs with tailored assemblies suitable for drug delivery systems. © 2018 by the authors.https://www.mdpi.com/1420-3049/23/4/96

    Reoxidation of the NADPH produced by the pentose phosphate pathway is necessary for the utilization of glucose by Kluyveromyces lactis rag2 mutants

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    AbstractKluyveromyces lactis mutants defective in the glycolytic enzyme phosphoglucose isomerase are able to grow in glucose media and to produce ethanol, but they depend on a functional respiratory chain and do not grow in glucose-antimycin media. We postulate that this is due to the necessity of reoxidizing, in the mitochondria, the NADPH produced by the pentose phosphate pathway, which may be highly active in these mutants in order to bypass the blockade in the phosphoglucose isomerase step. This oxidation would be mediated by a cytoplasmic-side mitochondrial NAD(P)H dehydrogenase that would pass the electrons to ubiquinone. Data supporting this hypothesis are provided

    IMPACTOS SOCIALES Y ECONÓMICOS DEL TURISMO EN UNA COMUNIDAD RURAL DE SAN LUIS POTOSÍ, MÉXICO

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    Through semi-structured interviews, observation and application of a survey, the perceptions regarding social organization, wellbeing in the community environment, and relationship of local economic activities were identified, of residents in Unión de Guadalupe, San Luis Potosí, México, facing the implementation of tourism in the community. Management is the foundation to promote, develop and broaden the tourism offer, creating and consolidating values in the inhabitants of the place themselves; community participation, gender equity, and collaboration from young people, are components that support the organizations in charge of the town to open opportunities for development; likewise, generating jobs, increasing the monetary income in families, and improving the basic services in the community, are the result from identifying impacts for the creation of strategies that can attain local development in the community. The methodology applied revealed that tourism is an alternative for the communities in the rural environment that have natural and cultural attractions, customs, traditions, lifestyles and habits that rural societies practice to become consolidated and to promote themselves in national and international settings.A través de entrevistas semi estructuradas, observación y aplicación de una encuesta se identificaron las percepciones en cuanto a la organización social, bienestar que presenta el entorno comunitario y relación de las actividades económicas locales ante la implementación del turismo en la comunidad, de los habitantes de la Unión de Guadalupe, San Luis Potosí, México. La gestión es cimiento para promover, desarrollar y ampliar la oferta turística, creando y consolidando valores en los propios habitantes del lugar; la participación comunitaria, la igualdad de género y colaboración de jóvenes son componentes que apoyan a las organizaciones encargadas del pueblo para abrir oportunidades de desarrollo; así mismo, generar empleos, aumentar el ingreso monetario en las familias y mejorar servicios básicos en la comunidad, son resultado de la identificación de impactos para la creación de estrategias que logren conseguir un desarrollo local en la comunidad. La metodología aplicada, reveló que el turismo es una alternativa para las comunidades del medio rural que cuentan con atractivos naturales y culturales, costumbres, tradiciones, modos de vida y hábitos que las sociedades rurales practican para consolidarse y promoverse en entornos nacionales e internacionales

    Discriminant Canonical Analysis as a Validation Tool for Multivariety Native Breed Egg Commercial Quality Classification

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    This study aimed to develop a tool to validate multivariety breed egg quality classification depending on quality-related internal and external traits using a discriminant canonical analysis approach. A flock of 60 Utrerana hens (Franciscan, White, Black, and Partridge) and a control group of 10 Leghorn hens were placed in individual cages to follow the traceability of the eggs and perform an individual internal and external quality assessment. Egg groups were determined depending on their commercial size (S, M, L, and XL), laying hen breed, and variety. Egg weight, major diameter, minor diameter, shell b*, albumen height, and the presence or absence of visual defects in yolk and/or albumen showed multicollinearity problems (variance inflation factor (VIF) > 5) and were discarded. Albumen weight, eggshell weight, and yolk weight were the most responsible traits for the differences among egg quality categories (Wilks’ lambda: 0.335, 0.539, and 0.566 for albumen weight, eggshell weight, and yolk weight, respectively). The combination of traits in the first two dimensions explained 55.02% and 20.62% variability among groups, respectively. Shared properties between Partridge and Franciscan varieties may stem from their eggs presenting heavier yolks and slightly lower weights, while White Utrerana and Leghorn hens’ similarities may be ascribed to hybridization reminiscences

    Micronized bran enriched fresh egg tagliatelle: significance of gums addition on pasta technological features

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    [EN] The aim of the work was to produce fibre-enriched fresh pasta based on micronised wheat bran and durum wheat semolina with appropriate techno-functional properties. Wheat semolina was replaced with fine particle size (50% below 75 mu m) wheat bran - up to 11.54% (w/w). A Box-Behnken design with randomised response surface methodology was used to determine a suitable combination of carboxymethylcellulose, xanthan gum and locust bean gum to improve pasta attributes: minimum cooking loss, maximum values for water gain and swelling index, as well as better colour and texture characteristics before and after cooking. The proximate chemical composition of wheat semolina and bran was determined and the microstructure of uncooked pasta was observed as well. From the response surface methodology analysis, it is recommended to use: (i) xanthan gum over 0.6% w/w as it led to bran-enriched pasta with a better developed structure and superior cooking behaviour, (ii) a combination of xanthan gum (0.8% w/w) and carboxymethylcellulose (over 0.6% w/w) to enhance uncooked pasta yellowness.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Authors would like to thank the Conselleria de Empresa, Universidad y Ciencia, Generalitat Valenciana (Spain) for financial support throughout the project AICO/2016/056.Martín-Esparza, M.; Raga-Soriano, A.; González Martínez, MC.; Albors, A. (2018). Micronized bran enriched fresh egg tagliatelle: significance of gums addition on pasta technological features. Food Science and Technology International. 24(4):309-320. https://doi.org/10.1177/1082013217750683S30932024

    Optimización de un método de detección y seguimiento de instrumental quirúrgico en video laparoscópico

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    La localización del instrumental quirúrgico es de gran interés en Cirugía Mínimamente Invasiva (CMI). Determinar su posición con precisión es fundamental para el desarrollo de futuras aplicaciones tanto en la formación y evaluación de cirujanos como en el desarrollo de nuevos sistemas de navegación que asistan al cirujano durante la propia intervención quirúrgica. En la literatura existen técnicas de estimación basadas en el análisis de imágenes, siendo la principal limitación común la gran variabilidad de las imágenes de este tipo de cirugía, que dificultan el diseño de un método genérico capaz de obtener buenas precisiones para todas ellas. En este trabajo de investigación se propone una optimización de un método de detección y seguimiento automático de instrumental quirúrgico basado en el análisis de video endoscópico, incorporando filtros homomórficos, un nuevo algoritmo de segmentación y un seguimiento mediante enventanado. Los resultados obtenidos muestran que el método propuesto consigue una detección precisa y robusta para imágenes con diferentes características sin necesidad de ninguna adaptación previa

    The Study of Growth and Performance in Local Chicken Breeds and Varieties: A Review of Methods and Scientific Transference

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    A review of the scientific advances in the study of the growth and performance in native chicken breeds and varieties over the past 20 years was performed. Understanding the growth patterns of native breeds can only be achieved if the constraints characterizing these populations are considered and treated accordingly. Contextually, the determination of researchers to use the same research methods and study designs applied in international commercial poultry populations conditions the accuracy of the model, variability capturing ability, and the observational or predictive performance when the data of the local population are fitted. Highly skewed sex ratios favouring females, an inappropriate census imbalance compensation and a lack of population structure render models that are regularly deemed effective as invalid to issue solid and sound conclusions. The wider the breed diversity is in a country, the higher the scientific attention paid to these populations. A detailed discussion of the most appropriate models and underlying reasons for their suitability and the reasons preventing the use of others in these populations is provided. Furthermore, the factors conditioning the scientific reception and impact of related publications used to transfer these results to the broad scientific public were evaluated to serve as guidance for the maximization of the success and dissemination of local breed information
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