Structural and magnetic properties of an InGaAs/Fe3_3Si superlattice in cylindrical geometry

The structure and the magnetic properties of an InGaAs/Fe3Si superlattice in a cylindrical geometry are investigated by electron microscopy techniques, x-ray diffraction and magnetometry. To form a radial superlattice, a pseudomorphic InGaAs/Fe3As bilayer has been released from its substrate self-forming into a rolled-up microtube. Oxide-free interfaces as well as areas of crystalline bonding are observed and an overall lattice mismatch between succeeding layers is determined. The cylindrical symmetry of the final radial superlattice shows a significant effect on the magnetization behavior of the rolled-up layers

Narrativas como recurso para la Enseñanza de las Ciencias : un caso con la historia de la tabla periódica

En este trabajo analizamos el aprendizaje de alumnos de 8vo año de enseñanza básica, en Brasil, delante de aspectos de la historia de la Química, al utilizar el enfoque narrativo y descriptivo en aulas. El análisis de los textos producidos por los estudiantes mostró variaciones significativas en el aprendizaje de un mismo contenido cuando el profesor utiliza géneros discursivos distintos. Cuando el abordaje del contenido es apenas descriptivo los alumnos enfatizan la definición de conceptos y no demuestran interés por lo aprendido. Las redacciones de los alumnos expuestos a aulas narrativas, demuestran la riqueza de detalles aprendidos, la valorización del orden cronológico de los descubrimientos y una admiración por los científicos participantes de la construcción de la tabla periódica

Narrativas como recurso para la Enseñanza de las Ciencias : un caso con la historia de la tabla periódica

En este trabajo analizamos el aprendizaje de alumnos de 8vo año de enseñanza básica, en Brasil, delante de aspectos de la historia de la Química, al utilizar el enfoque narrativo y descriptivo en aulas. El análisis de los textos producidos por los estudiantes mostró variaciones significativas en el aprendizaje de un mismo contenido cuando el profesor utiliza géneros discursivos distintos. Cuando el abordaje del contenido es apenas descriptivo los alumnos enfatizan la definición de conceptos y no demuestran interés por lo aprendido. Las redacciones de los alumnos expuestos a aulas narrativas, demuestran la riqueza de detalles aprendidos, la valorización del orden cronológico de los descubrimientos y una admiración por los científicos participantes de la construcción de la tabla periódica

N-terminal pro-B-type natriuretic peptide by itself predicts death and cardiovascular events in high-risk patients with type 2 diabetes

Background: NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide) improves the discriminatory ability of risk‐prediction models in type 2 diabetes mellitus (T2DM) but is not yet used in clinical practice. We assessed the discriminatory strength of NT‐proBNP by itself for death and cardiovascular events in high‐risk patients with T2DM. Methods and Results: Cox proportional hazards were used to create a base model formed by 20 variables. The discriminatory ability of the base model was compared with that of NT‐proBNP alone and with NT‐proBNP added, using C‐statistics. We studied 5509 patients (with complete data) of 8561 patients with T2DM and cardiovascular and/or chronic kidney disease who were enrolled in the ALTITUDE (Aliskiren in Type 2 Diabetes Using Cardiorenal Endpoints) trial. During a median 2.6‐year follow‐up period, 469 patients died and 768 had a cardiovascular composite outcome (cardiovascular death, resuscitated cardiac arrest, nonfatal myocardial infarction, stroke, or heart failure hospitalization). NT‐proBNP alone was as discriminatory as the base model for predicting death (C‐statistic, 0.745 versus 0.744, P=0.95) and the cardiovascular composite outcome (C‐statistic, 0.723 versus 0.731, P=0.37). When NT‐proBNP was added, it increased the predictive ability of the base model for death (C‐statistic, 0.779 versus 0.744, P<0.001) and for cardiovascular composite outcome (C‐statistic, 0.763 versus 0.731, P<0.001). Conclusions: In high‐risk patients with T2DM, NT‐proBNP by itself demonstrated discriminatory ability similar to a multivariable model in predicting both death and cardiovascular events and should be considered for risk stratification

Rolled-up tubes and cantilevers by releasing SrRuO₃-Pr₀̣₇Ca₀̣₃MnO₃ nanomembranes

Three-dimensional micro-objects are fabricated by the controlled release of inherently strained SrRuO3/ Pr0.7Ca0.3MnO3/SrRuO3 nanometer-sized trilayers from SrTiO3(001) substrates. Freestanding cantilevers and rolled-up microtubes with a diameter of 6 to 8 μm are demonstrated. The etching behavior of the SrRuO3 film is investigated, and a selectivity of 1:9,100 with respect to the SrTiO3 substrate is found. The initial and final strain states of the rolled-up oxide layers are studied by X-ray diffraction on an ensemble of tubes. Relaxation of the sandwiched Pr0.7Ca0.3MnO3 layer towards its bulk lattice parameter is observed as the major driving force for the roll-up of the trilayers. Finally, μ-diffraction experiments reveal that a single object can represent the ensemble proving a good homogeneity of the rolled-up tubes. PACS: 81.07.-b; 68.60.-p; 68.37.Lp; 81.16.Dn