Ubiquitinación de proteínas nucleares en la señalización del ayuno de fosfato en plantas

Comunicaciones a congreso

Prevalencia y factores asociados con deficiencia de vitamina D en una población adulta joven de dos instituciones de educación superior en Cali y Bogotá: estudio de corte transversal

La deficiencia de vitamina D es considerado un problema de salud pública. Aunque algunos estudios han evaluado la deficiencia de vitamina D en poblaciones de riesgo (adultos mayores, posmenopáusicas), existen pocos datos en población adulta joven y mucho menos en poblaciones latinoamericanas. Se realizó un estudio de corte transversal con 205 universitarios entre 18 y 45 años en 2 ciudades colombianas para establecer la prevalencia y los factores asociados con la deficiencia de vitamina D. Se consideró como deficiencia de vitamina D un valor menor o igual de 20 ng/mL de 25-hidroxivitamina-D. Se estableció una prevalencia de deficiencia de vitamina D del 22,4 % (IC 95 % 17- 29). Se encontró que el género masculino y fototipo Fitzpatrick IV se asociaron de manera independiente con mayor riesgo de deficiencia de vitamina D, mientras el consumo de pescado y la exposición al sol de miembros inferiores al hacer ejercicio lo disminuyeron

Conformal TiO2_2 aerogel-like films by plasma deposition: from omniphobic antireflective coatings to perovskite solar cells photoelectrodes

The ability to control porosity in oxide thin films is one of the key factors that determine their properties. Despite the abundance of dry processes for the synthesis of oxide porous layers, the high porosity range is typically achieved by spin-coating-based wet chemical methods. Besides, special techniques such as supercritical drying are required to replace the pore liquid with air while maintaining the porous network. In this study, we propose a new method for the fabrication of ultra-porous titanium dioxide thin films at room or mild temperatures (T lower or equal to 120 degrees Celsius) by the sequential process involving plasma deposition and etching. These films are conformal to the substrate topography even for high-aspect-ratio substrates and show percolated porosity values above 85 percent that are comparable to advanced aerogels. The films deposited at room temperature are amorphous. However, they become partly crystalline at slightly higher temperatures presenting a distribution of anatase clusters embedded in the sponge-like structure. Surprisingly, the porous structure remains after annealing the films at 450 degrees Celsius in air, which increases the fraction of the embedded anatase nanocrystals. The films are antireflective, omniphobic, and photoactive becoming super-hydrophilic subjected to UV light irradiation The supported percolated nanoporous structure can be used as an electron-conducting electrode in perovskite solar cells. The properties of the cells depend on the aerogel film thickness reaching efficiencies close to those of commercial mesoporous anatase electrodes. This generic solvent-free synthesis is scalable and is applicable to ultra-high porous conformal oxides of different compositions with potential applications in photonics, optoelectronics, energy storage, and controlled wetting.Comment: 31 pages, 10 Figs. plus Supporting Information 7 pags, 6 figs. Full Pape

Reconstructing Native American population history

The peopling of the Americas has been the subject of extensive genetic, archaeological and linguistic research; however, central questions remain unresolved. One contentious issue is whether the settlement occurred by means of a single migration or multiple streams of migration from Siberia. The pattern of dispersals within the Americas is also poorly understood. To address these questions at a higher resolution than was previously possible, we assembled data from 52 Native American and 17 Siberian groups genotyped at 364,470 single nucleotide polymorphisms. Here we show that Native Americans descend from at least three streams of Asian gene flow. Most descend entirely from a single ancestral population that we call First American. However, speakers of Eskimog-Aleut languages from the Arctic inherit almost half their ancestry from a second stream of Asian gene flow, and the Na-Dene-speaking Chipewyan from Canada inherit roughly one-tenth of their ancestry from a third stream. We show that the initial peopling followed a southward expansion facilitated by the coast, with sequential population splits and little gene flow after divergence, especially in South America. A major exception is in Chibchan speakers on both sides of the Panama isthmus, who have ancestry from both North and South America. © 2012 Macmillan Publishers Limited. All rights reserved.Fil: Reich, David. Harvard Medical School; Estados Unidos. Massachusetts Institute of Technology; Estados UnidosFil: Patterson, Nick. Massachusetts Institute of Technology; Estados UnidosFil: Campbell, Desmond. Colegio Universitario de Londres; Reino Unido. The University Of Hong Kong; Hong KongFil: Tandon, Arti. Harvard Medical School; Estados Unidos. Massachusetts Institute of Technology; Estados UnidosFil: Mazieres, Stéphane. Colegio Universitario de Londres; Reino UnidoFil: Ray, Nicolas. Universidad de Ginebra; SuizaFil: Parra, Maria V.. Colegio Universitario de Londres; Reino Unido. Universidad de Antioquia; ColombiaFil: Rojas, Winston. Colegio Universitario de Londres; Reino Unido. Universidad de Antioquia; ColombiaFil: Duque, Constanza. Universidad de Antioquia; Colombia. Colegio Universitario de Londres; Reino UnidoFil: Mesa, Natalia. Universidad de Antioquia; Colombia. Colegio Universitario de Londres; Reino UnidoFil: García, Luis F.. Universidad de Antioquia; ColombiaFil: Triana, Omar. Universidad de Antioquia; ColombiaFil: Blair, Silvia. Universidad de Antioquia; ColombiaFil: Maestre, Amanda. Universidad de Antioquia; ColombiaFil: Dib, Juan C.. Fundación Salud Para El Tró Pico; ColombiaFil: Bravi, Claudio Marcelo. Colegio Universitario de Londres; Reino Unido. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; ArgentinaFil: Bailliet, Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; ArgentinaFil: Corach, Daniel. Universidad de Buenos Aires; ArgentinaFil: Hünemeier, Tábita. Colegio Universitario de Londres; Reino Unido. Universidade Federal do Rio Grande do Sul; BrasilFil: Bortolini, Maria Cátira. Universidade Federal do Rio Grande do Sul; BrasilFil: Salzano, Francisco M.. Universidade Federal do Rio Grande do Sul; BrasilFil: Petzl Erler, María Luiza. Universidade Federal do Paraná; BrasilFil: Acuña Alonzo, Victor. National Institute Of Anthropology And History; MéxicoFil: Aguilar Salinas, Carlos. Instituto Nacional de la Nutrición Salvador Zubiran; MéxicoFil: Canizales-Quinteros, Samuel. Universidad Nacional Autónoma de México; MéxicoFil: Tusié Luna, Teresa. Universidad Nacional Autónoma de México; MéxicoFil: Riba, Laura. Universidad Nacional Autónoma de México; MéxicoFil: Rodríguez Cruz, Maricela. Umae Hospital de Pediatría Centro Medico Nacional Siglo Xxi; MéxicoFil: Lopez Alarcón, Mardia. Umae Hospital de Pediatría Centro Medico Nacional Siglo Xxi; MéxicoFil: Coral Vazquez, Ramón. Instituto Politécnico Nacional; Méxic

Dung removal increases under higher dung beetle functional diversity regardless of grazing intensification

Dung removal by macrofauna such as dung beetles is an important process for nutrient cycling in pasturelands. Intensification of farming practices generally reduces species and functional diversity of terrestrial invertebrates, which may negatively affect ecosystem services. Here, we investigate the effects of cattle-grazing intensification on dung removal by dung beetles in field experiments replicated in 38 pastures around the world. Within each study site, we measured dung removal in pastures managed with low- and high-intensity regimes to assess between-regime differences in dung beetle diversity and dung removal, whilst also considering climate and regional variations. The impacts of intensification were heterogeneous, either diminishing or increasing dung beetle species richness, functional diversity, and dung removal rates. The effects of beetle diversity on dung removal were more variable across sites than within sites. Dung removal increased with species richness across sites, while functional diversity consistently enhanced dung removal within sites, independently of cattle grazing intensity or climate. Our findings indicate that, despite intensified cattle stocking rates, ecosystem services related to decomposition and nutrient cycling can be maintained when a functionally diverse dung beetle community inhabits the human-modified landscape

Reconstructing Native American Population History

The peopling of the Americas has been the subject of extensive genetic, archaeological and linguistic research; however, central questions remain unresolved1–5. One contentious issue is whether the settlement occurred via a single6–8 or multiple streams of migration from Siberia9–15. The pattern of dispersals within the Americas is also poorly understood. To address these questions at higher resolution than was previously possible, we assembled data from 52 Native American and 17 Siberian groups genotyped at 364,470 single nucleotide polymorphisms. We show that Native Americans descend from at least three streams of Asian gene flow. Most descend entirely from a single ancestral population that we call “First American”. However, speakers of Eskimo-Aleut languages from the Arctic inherit almost half their ancestry from a second stream of Asian gene flow, and the Na-Dene-speaking Chipewyan from Canada inherit roughly one-tenth of their ancestry from a third stream. We show that the initial peopling followed a southward expansion facilitated by the coast, with sequential population splits and little gene flow after divergence, especially in South America. A major exception is in Chibchan-speakers on both sides of the Panama Isthmus, who have ancestry from both North and South America

Effect of sitagliptin on cardiovascular outcomes in type 2 diabetes

BACKGROUND: Data are lacking on the long-term effect on cardiovascular events of adding sitagliptin, a dipeptidyl peptidase 4 inhibitor, to usual care in patients with type 2 diabetes and cardiovascular disease. METHODS: In this randomized, double-blind study, we assigned 14,671 patients to add either sitagliptin or placebo to their existing therapy. Open-label use of antihyperglycemic therapy was encouraged as required, aimed at reaching individually appropriate glycemic targets in all patients. To determine whether sitagliptin was noninferior to placebo, we used a relative risk of 1.3 as the marginal upper boundary. The primary cardiovascular outcome was a composite of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for unstable angina. RESULTS: During a median follow-up of 3.0 years, there was a small difference in glycated hemoglobin levels (least-squares mean difference for sitagliptin vs. placebo, -0.29 percentage points; 95% confidence interval [CI], -0.32 to -0.27). Overall, the primary outcome occurred in 839 patients in the sitagliptin group (11.4%; 4.06 per 100 person-years) and 851 patients in the placebo group (11.6%; 4.17 per 100 person-years). Sitagliptin was noninferior to placebo for the primary composite cardiovascular outcome (hazard ratio, 0.98; 95% CI, 0.88 to 1.09; P<0.001). Rates of hospitalization for heart failure did not differ between the two groups (hazard ratio, 1.00; 95% CI, 0.83 to 1.20; P = 0.98). There were no significant between-group differences in rates of acute pancreatitis (P = 0.07) or pancreatic cancer (P = 0.32). CONCLUSIONS: Among patients with type 2 diabetes and established cardiovascular disease, adding sitagliptin to usual care did not appear to increase the risk of major adverse cardiovascular events, hospitalization for heart failure, or other adverse events

Effects of Once-Weekly Exenatide on Cardiovascular Outcomes in Type 2 Diabetes.

Abstract BACKGROUND: The cardiovascular effects of adding once-weekly treatment with exenatide to usual care in patients with type 2 diabetes are unknown. METHODS: We randomly assigned patients with type 2 diabetes, with or without previous cardiovascular disease, to receive subcutaneous injections of extended-release exenatide at a dose of 2 mg or matching placebo once weekly. The primary composite outcome was the first occurrence of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke. The coprimary hypotheses were that exenatide, administered once weekly, would be noninferior to placebo with respect to safety and superior to placebo with respect to efficacy. RESULTS: In all, 14,752 patients (of whom 10,782 [73.1%] had previous cardiovascular disease) were followed for a median of 3.2 years (interquartile range, 2.2 to 4.4). A primary composite outcome event occurred in 839 of 7356 patients (11.4%; 3.7 events per 100 person-years) in the exenatide group and in 905 of 7396 patients (12.2%; 4.0 events per 100 person-years) in the placebo group (hazard ratio, 0.91; 95% confidence interval [CI], 0.83 to 1.00), with the intention-to-treat analysis indicating that exenatide, administered once weekly, was noninferior to placebo with respect to safety (P<0.001 for noninferiority) but was not superior to placebo with respect to efficacy (P=0.06 for superiority). The rates of death from cardiovascular causes, fatal or nonfatal myocardial infarction, fatal or nonfatal stroke, hospitalization for heart failure, and hospitalization for acute coronary syndrome, and the incidence of acute pancreatitis, pancreatic cancer, medullary thyroid carcinoma, and serious adverse events did not differ significantly between the two groups. CONCLUSIONS: Among patients with type 2 diabetes with or without previous cardiovascular disease, the incidence of major adverse cardiovascular events did not differ significantly between patients who received exenatide and those who received placebo. (Funded by Amylin Pharmaceuticals; EXSCEL ClinicalTrials.gov number, NCT01144338 .)