Dual-function injectable angiogenic biomaterial for the repair of brain tissue following stroke.

Stroke is the primary cause of disability due to the brain's limited ability to regenerate damaged tissue. After stroke, an increased inflammatory and immune response coupled with severely limited angiogenesis and neuronal growth results in a stroke cavity devoid of normal brain tissue. In the adult, therapeutic angiogenic materials have been used to repair ischaemic tissues through the formation of vascular networks. However, whether a therapeutic angiogenic material can regenerate brain tissue and promote neural repair is poorly understood. Here we show that the delivery of an engineered immune-modulating angiogenic biomaterial directly to the stroke cavity promotes tissue formation de novo, and results in axonal networks along thee generated blood vessels. This regenerated tissue produces functional recovery through the established axonal networks. Thus, this biomaterials approach generates a vascularized network of regenerated functional neuronal connections within previously dead tissue and lays the groundwork for the use of angiogenic materials to repair other neurologically diseased tissues

Optical absorption of divalent metal tungstates: Correlation between the band-gap energy and the cation ionic radius

We have carried out optical-absorption and reflectance measurements at room temperature in single crystals of AWO4 tungstates (A = Ba, Ca, Cd, Cu, Pb, Sr, and Zn). From the experimental results their band-gap energy has been determined to be 5.26 eV (BaWO4), 5.08 eV (SrWO4), 4.94 eV (CaWO4), 4.15 eV (CdWO4), 3.9-4.4 eV (ZnWO4), 3.8-4.2 eV (PbWO4), and 2.3 eV (CuWO4). The results are discussed in terms of the electronic structure of the studied tungstates. It has been found that those compounds where only the s electron states of the A2+ cation hybridize with the O 2p and W 5d states (e.g BaWO4) have larger band-gap energies than those where also p, d, and f states of the A2+ cation contribute to the top of the valence band and the bottom of the conduction band (e.g. PbWO4). The results are of importance in view of the large discrepancies existent in prevoiusly published data.Comment: 16 pages, 3 figures, 1 tabl

Counterfactual thinking in everyday life situations: Temporal order effects and social norms.

Razonamiento contrafáctico en situaciones de la vida diaria: Efectos de
 orden temporales y normas sociales. El razonamiento contrafáctico es la
 comparación de una situación fáctica con una alternativa simulada. Cuando
 las personas imaginan cómo las cosas podrían haber sido diferentes, tienden
 a deshacer mentalmente el último suceso de una secuencia de
 acontecimientos independientes previos a un resultado. Se presentan dos
 experimentos que examinan este fenómeno que ha sido denominado el
 efecto de orden temporal. El primer experimento, con 132 participantes,
 examinó el efecto de variar el número de eventos de la vida diaria en el
 efecto de orden temporal. Los resultados muestran que en situaciones
 cotidianas, es necesario un número suficiente de sucesos para que efecto se
 produzca. El segundo experimento, con 177 participantes, examinó una
 posible relación entre el efecto de orden temporal con un efecto diferente: la
 tendencia a cambiar eventos controlables que son excepcionales respecto a
 las normas interpersonales de conducta. Los resultados muestran que la
 posición en una secuencia temporal de sucesos independientes afecta a la
 facilidad para cambiar esos eventos excepcionales. Los resultados se
 discuten en términos de normas sociales

The connection between entropy and the absorption spectra of Schwarzschild black holes for light and massless scalar fields

We present heuristic arguments suggesting that if EM waves with wavelengths somewhat larger than the Schwarzschild radius of a black hole were fully absorbed by it, the second law of thermodynamics would be violated, under the Bekenstein interpretation of the area of a black hole as a measure of its entropy. Thus, entropy considerations make the well known fact that large wavelengths are only marginally absorbed by black holes, a natural consequence of thermodynamics. We also study numerically the ingoing radial propagation of a scalar field wave in a Schwarzschild metric, relaxing the standard assumption which leads to the eikonal equation, that the wave has zero spatial extent. We find that if these waves have wavelengths larger that the Schwarzschild radius, they are very substantially reflected, fully to numerical accuracy. Interestingly, this critical wavelength approximately coincides with the one derived from entropy considerations of the EM field, and is consistent with well known limit results of scattering in the Schwarzschild metric. The propagation speed is also calculated and seen to differ from the value $c$, for wavelengths larger than $R_{s}$, in the vicinity of $R_{s}$. As in all classical wave phenomena, whenever the wavelength is larger or comparable to the physical size of elements in the system, in this case changes in the metric, the zero extent 'particle' description fails, and the wave nature becomes apparent.Comment: 14 Pages, 4 figures. Accepted for publication in the Journal Entrop

Further developments in stress initialization in geomechanics via FEM and a two-step procedure involving airy functions

The in-situ stress field in rock masses is a key aspect when a numerical analysis of a rock mass is carried out in any area of geo-engineering, such as civil, mining, or Oil & Gas. A method for the numerical generation of the in-situ stress state in the FE context, based on Airy stress functions was previously introduced. It involves two steps: 1) an estimate of the stress state at each Gauss point is generated, and 2) global equilibrium is verified and re-balancing nodal forces are applied as needed. In this paper, new developments towards improving the accuracy of the stress proposal are discussed. A real application example has been used to illustrate the results achieved with the new implementation

Impact of nitrogen fertilization on guinea grass (Panicum maximum, Jacq) in the humid premountain forest in the Department of Tolima.

P?ginas 17-21El objetivo del trabajo de investigaci?n fue evaluar la respuesta de diferentes dosis (0, 100, 150 y 300 kg/ha) de nitr?geno en la producci?n de pasto guinea (Panicum maximum, Jacq). Los resultados servir?n para establecer una recomendaci?n t?cnico-econ?mica viable de fertilizaci?n para la producci?n de esta gram?nea bajo condiciones de bosque h?medo sub-andino. El dise?o experimental utilizado fue bloques completos al azar con las cuatro dosis de nitr?geno mencionadas. Se aplic? 246 y 60 kg ha/a?o de CaCO3 y K2 O, respectivamente para correcci?n del pH. La producci?n y el porcentaje de materia seca en el forraje fueron medidos en los tres cortes realizados a intervalos de 28 d?as. Los cortes presentaron efecto significativo (P<0,01) en la producci?n y porcentaje de materia seca. La mayor producci?n de materia seca se encontr? en el corte dos (56 d?as) con 0,23 kg/m2 y el m?ximo porcentaje de MS se encontr? en el corte tres (84 d?as) con 21,4%; mientras que la fertilizaci?n de 300 kg N/ha/a?o present? el mayor rendimiento productivo de la gram?nea. La mayor rentabilidad financiera fue encontrada en el testigo (0 kg N/ha/a?o).ABSTRACT. The goal of this study was to evaluate different levels of nitrogen fertilization (0, 100, 150 and 300 kg/ha/year) on the production of Guinea grass (Panicum maximum). The results should support a viable technical-economical recommendation of fertilization for the production of this grass under sub-Andean humid forest conditions. An experimental design of randomized blocks was used, with four treatments of nitrogen fertilization. It was also applied to all plots 246 and 60 kg/ha/yearof CaCO3 and K2O as pH corrective inputs. The production and percentage of dry mater were evaluated in all three cuttings, which were carried out every 28 days. The cutting presented a significant effect (P<0.01) in the production and percentage of dry matter. The highest dry matter production was found in the second cutting (56 days) with 0.23 kg/m2; and the highest dry matter percentage was found in the third cutting (84 days) with 21%; whereas, the fertilization with 300kg N/ha/year showed the highest grass productivity. The greatest financial profitability was found in the control treatment (0 kg N/ha/year)