Nano-composite single grain YBa2Cu3O 7-δ/Y2Ba4CuBiOy bulk superconductors

We have succeeded recently in synthesizing a chemically stable, inert family of materials of composition Y2Ba4CuMOy (Y-2411 where M Nb, Ta, Mo, W, Zr, Hf) within the superconducting YBa 2Cu3O7-δ (Y-123) phase matrix that forms effective flux pinning centers of nano-scale dimensions. In this paper we report the synthesis of the Y2Ba4CuBiOy phase with nano-scale dimensions that is similarly compatible with the Y-123 matrix and which does not impair the properties of the bulk superconductor. YBa 2Cu3O7-δ/Y2BaCuO5 (Y-123/Y-211) precursor powders enriched with various amounts of Bi 2O3 and Y2Ba4CuBiOy have been fabricated successfully in the form of large, single grains by the top seeded melt growth (TSMG) process. Microstructural studies of these composites reveal the presence of nanometer-sized Y2Ba4CuBiO y and much larger Y-211 phase particles (∼1 νm) embedded in the Y-123 phase matrix. The critical current density of the nano-composites is observed to increase significantly compared to undoped YBCO. © 2006 IOP Publishing Ltd

Comparison and characterization of chitinase in Cornus species

This research has demonstrated that there is a significant difference between a Dogwood Anthracnose resistant Cornus species than a susceptible species in chitinase activity following inoculation with Discula. Cornus mas (resistant) and Cornus florida (susceptible) were inoculated with Discula destructiva, (cause of Dogwood Anthracnose disease) and leaves were collected over a 12 day period. Protein from the inoculated leaves was extracted and assayed colorimetrically and enzymatically for chitinase in this investigation. Chitinase characterization was accomplished through the use of the Phastsystem to determine the iso-electric points and SDSpolyacrylamide gel electrophoresis for the molecular weight determinations. Colorimetric assay indicates chitinase activity in Cornus mas is expressed earlier than Cornus florida following infection. The enzymatic assay indicates the presence of activity over all days post-inoculation in both Cornus mas and Cornus florida. Two iso-electric points were determined for Cornus florida and three determined for Cornus mas. By using SDS-polyacrylamide gel electrophoresis, the molecular weights were identified as 65 +/- 5 kDa and 21 kDa in for both Cornus species. The iso-electric points were determined to be 5.6, 6.8, and 8.9 for Cornus mas and 5.6 and 6.8 for Cornus florida

The Universal Andalusian, The Zealous Andalusian, and the Andalusian Elegy.

Biographers and critics have been content to repeat Juan Ramón Jiménez\u27 own comments concerning the influence upon him of Krausism, the Institución Libre de Enseñanza and the personality and model of Francisco Giner de los Ríos. In general, little discussion of the nature of that contact and virtually no evidence for arguing the importance or the shape of Krausist ethos on Jiménez\u27 intellectual formation have been adduced. In previous studies I have considered Jiménez\u27 literary apprenticeship in the light of the Krausist contacts. In the present study I further contend that Platero у уо, arguably his best known work, represents not only a major statement of the poet\u27s idealism but that it was written under the spell of Giner\u27s example and teachings. Platero is not only a story for children, it was intended also as an example of Giner\u27s pedagogía íntima. As such the work can take its place in the main corpus of the poet\u27s work as yet another statement of la ética estética. This essay further clarifies the formative ideological influence of Giner\u27s idealism

Bulk superconducting nano-composites with high critical currents

Flux pinning sites are most effective if their size is comparable to the superconducting coherence length, which is on the nano-meter scale for RE-Ba-Cu-O superconductors [RE = rare earth element]. Introducing nano-phase inclusions directly into the bulk superconducting material has only been partially successful to date, however, due primarily to the absence of chemically stable phases that can co-exist with RE-Ba-Cu-O without suppressing its key superconducting properties. We have identified novel isostructural phases based on (RE)2Ba4CuMOy (where M = W, Zr, Nb, Ag and Bi) and have fabricated successfully superconducting bulk nano-composites with a high current carrying capability. The average size of the nano-inclusions is observed to vary from 20 nm to 300 nm depending on element M. An observed improvement in Jc under low and high external magnetic fields at 77 K correlates directly with an increased density of nano-inclusions in the superconducting matrix

Synthesis of dense bulk MgB2 by an infiltration and growth process

We report the processing of dense, superconducting MgB2 (2.4 g cm-3) by an infiltration and growth technique. The process, which involves infiltration of liquid magnesium at 750 C into a pre-defined boron precursor pellet, is relatively simple, results in the formation of a hard, dense structure and has the potential to fabricate large bulk samples of complex geometries. X-ray diffraction has been used to confirm the presence of the MgB2 primary phase with only residual magnesium content in the fully processed samples. The samples exhibit sharp superconducting transitions at 38.4 K and have critical current densities of up to 260 kA cm-2 in self-field at 5 K. Modest measured values of Hc2(0) of 17 T suggest that superconductivity in bulk MgB2 fabricated by this technique is in the clean pairing limit

Dietary aflatoxin exposure and impaired growth in young children from Benin and Togo: cross sectional study

Fetal and early childhood environment, including the nutritional status of the pregnant mother and the infant, are considered critical for growth and risk of disease in later life. Many people in developing coun­ tries are not only malnourished but also chronically exposed to high levels of toxic fungal metabolites (mycotoxins). One family of mycotoxins, the aflatoxins, are carcinogenic and immunotoxic and cause growth retardation in animals. Aflatoxins contaminate staple foods in West Africa, particularly maize and ground­ nuts, as a result of hot, humid storage conditions that promote fungal growth. High exposure to aflatoxins occurs throughout childhood in the region, suggest­ ing that growth and development could be critically affected.We assessed exposure to aflatoxins in relation to anthropometric measures in children in Benin and Togo

“How Dare You Vote!” The Enactment of Racist and Undemocratic Voting Laws to Preserve White Supremacy, Maintain the Status Quo, and Prevent the Rise of the Black Vote – Saying the Quiet Parts Out Loud

Historically the United States has proudly described itself as a “melting pot,” declaring, “Give me your tired, your poor, your huddled masses yearning to breathe free.” However, if the truth is told, the United States of America has never been a melting pot. In a melting pot, the ingredients each contribute something to the pot that equalizes them into becoming a well-seasoned, indistinguishable meal. No one ingredient dominates the mixture, and each adds something that makes the pot richer. This country is more like a gumbo, a dish whose ingredients stand out, where some purportedly add more value to the mix than others. The term “purportedly” is intentional because the cook determines which ingredients are more deserving of being added to the gumbo and which should dominate the flavor, style, and end result. Yes, the United States of America is a gumbo, White supremacy has been the cook for far too long and the maintenance of power has been the main ingredient. America needs some new cooks in the kitchen. The right to vote has always been an unkept promise as America’s vision of equality has been distorted since its very inception. Many Americans believe the First Amendment is the most important right. The authors of this Article, however; believe that the right to vote is the foundational right because voting allows citizens to engage in the political process. Without participation in the political process, all other fundamental rights are diminished. While voting is touted as the cornerstone of American democracy, it is a promise repeatedly broken. We acknowledge that every person who is a minority in America, suffers from racism; however, but our focus here is on Black America