32 research outputs found

    Comte y el problema de la realidad

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    Enrique Molina y la búsqueda filosófica

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    Mad Is Required for Wingless Signaling in Wing Development and Segment Patterning in Drosophila

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    A key question in developmental biology is how growth factor signals are integrated to generate pattern. In this study we investigated the integration of the Drosophila BMP and Wingless/GSK3 signaling pathways via phosphorylations of the transcription factor Mad. Wingless was found to regulate the phosphorylation of Mad by GSK3 in vivo. In epistatic experiments, the effects of Wingless on wing disc molecular markers (senseless, distalless and vestigial) were suppressed by depletion of Mad with RNAi. Wingless overexpression phenotypes, such as formation of ectopic wing margins, were induced by Mad GSK3 phosphorylation-resistant mutant protein. Unexpectedly, we found that Mad phosphorylation by GSK3 and MAPK occurred in segmental patterns. Mad depletion or overexpression produced Wingless-like embryonic segmentation phenotypes. In Xenopus embryos, segmental border formation was disrupted by Smad8 depletion. The results show that Mad is required for Wingless signaling and for the integration of gradients of positional information

    Bench-scale extraction of stilbenoids and other phenolics from stored grape canes (Vitis vinifera): Optimization process, chemical characterization, and potential protection against oxidative damage

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    Dietary supplements have become the key to complement deficiencies in the occidental diet and therefore to reduce the incidence of oxidative stress related diseases. A bench-scale extraction procedure was studied to obtain a valuable product rich in phenolic compounds and antioxidant capacity from Pinot Noir grape cane enhanced by storage. Extraction solvent, cane-size, solid:liquid ratio, temperature, and extraction time, were systematically evaluated in order to obtain a natural functional product. Complete chemical characterization of a Pinot Noir grape cane extract produced under bench scale process is presented for the first time. Phenolic profiles of the extracts were characterized by HPLC-PDA-MS/MS and minerals by ICP-OES. Proteins, carbohydrates and lignins were also evaluated. The main phenolic compounds in the final product were stilbenoids, flavan-3-ols, procyanidins, and flavonols, with 6.53%, 4.84%, 2.11%, and 0.25%, respectively on a dry matter basis. Other chemical constituents were carbohydrates (27%), minerals (1%) and lignins (38.7%). The antioxidant capacity of the product was demonstrated using chemical assays (TEACABTS/CUPRAC and ORAC-FL) and endothelial cells model. The extract produced under the described bench scale process using grape cane enhanced by storage have a chemical composition and protecting capacities to be used in functional foods industry

    Latitude gradient influences the age of onset of rheumatoid arthritis : a worldwide survey

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    The age of onset of rheumatoid arthritis (RA) is an important outcome predictor. Northern countries report an age of RA onset of around 50 years, but apparently, variability exists across different geographical regions. The objective of the present study is to assess whether the age of onset of RA varies across latitudes worldwide. In a proof-of-concept cross-sectional worldwide survey, rheumatologists from preselected cities interviewed 20 consecutive RA patients regarding the date of RA onset (RAO, when the patient first noted a swollen joint). Other studied variables included location of each city, rheumatologist settings, latitudes (10A degrees increments, south to north), longitudes (three regions), intracountry consistency, and countries' Inequality-adjusted Human Development Index (IHDI). Data from 2481 patients (82% females) were obtained from 126 rheumatologists in 77 cities of 41 countries. Worldwide mean age of RAO was 44 +/- 14 years (95% CI 44-45). In 28% of patients, RA began before age 36 years and before age 46 years in 50% of patients. RAO was 8 years earlier around the Tropic of Cancer when compared with northern latitudes (p <0.001, 95% CI 3.5-13). Multivariate analysis showed that females, western cities, and latitudes around the Tropic of Cancer are associated with younger age of RAO (R (2) 0.045, p <0.001). A positive correlation was found between the age of RAO and IHDI (r = 0.7, p <0.01, R (2) 0.5). RA often begins at an early age and onset varies across latitudes worldwide. We postulate that countries' developmental status and their geographical and geomagnetic location influence the age of RAO.Peer reviewe

    Adult neural stem cells bridge their niche.

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    Adult neural stem cells bridge their niche.

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    Major developments in the neural stem cell (NSC) field in recent years provide new insights into the nature of the NSC niche. In this perspective, we integrate recent anatomical data on the organization of the two main neurogenic niches in the adult brain, the ventricular-subventricular zone (V-SVZ) and the subgranular zone (SGZ), with signaling pathways that control the behavior of NSCs. NSCs in the adult brain stretch into physiologically distinct compartments of their niche. We propose how adult NSCs' morphology may allow these cells to integrate multiple signaling pathways arising from unique locations of their niche

    Contradicciones latentes en los programas de formación de profesores en Chile. Buscando pistas para seguir el camino

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