Thermobaric Effect on Melt-Textured MBa2_2Cu3_3O7−δ_{7-\delta} (M = Y, Nd)

The effect of a short (10-30 min) thermobaric action (in the 1-5 GPa pressure and 700-1300$^\circ$C temperature range) on the structure, superconductive and mechanical properties of melt-textured-MBa$_2$Cu$_3$O$_{7-\delta}$ (M=Y, Nd) or MT-MBCO have been studied. The existence has been established of pressure-temperature--time conditions (2 GPa, 800$^\circ$C for 30 min and 900-950$^\circ$C for 15 min for MT-YBCO; 5 GPa, 850-900$^\circ$C for 15 min for MT-NdBCO) the treatment under which allows superconductive properties of the materials (because of the contact with zirconia and high pressure) to be preserved or improved, mechanical characteristics increased and the materials condensed.Comment: 2 pages (tex), 2 figures (eps), to be presented at LT2

A Novel System of Cytoskeletal Elements in the Human Pathogen Helicobacter pylori

Pathogenicity of the human pathogen Helicobacter pylori relies upon its capacity to adapt to a hostile environment and to escape from the host response. Therefore, cell shape, motility, and pH homeostasis of these bacteria are specifically adapted to the gastric mucus. We have found that the helical shape of H. pylori depends on coiled coil rich proteins (Ccrp), which form extended filamentous structures in vitro and in vivo, and are differentially required for the maintenance of cell morphology. We have developed an in vivo localization system for this pathogen. Consistent with a cytoskeleton-like structure, Ccrp proteins localized in a regular punctuate and static pattern within H. pylori cells. Ccrp genes show a high degree of sequence variation, which could be the reason for the morphological diversity between H. pylori strains. In contrast to other bacteria, the actin-like MreB protein is dispensable for viability in H. pylori, and does not affect cell shape, but cell length and chromosome segregation. In addition, mreB mutant cells displayed significantly reduced urease activity, and thus compromise a major pathogenicity factor of H. pylori. Our findings reveal that Ccrp proteins, but not MreB, affect cell morphology, while both cytoskeletal components affect the development of pathogenicity factors and/or cell cycle progression

Clinoptilolite-based mixed matrix membranes for the selective recovery of potassium and ammonium

. A clinoptilolite-based mixed matrix membrane (MMM) was developed and studied for the selective recovery of ammonium and potassium. Adsorption of sodium (Na+), potassium (K+) and ammonium (NH4+) was investigated with single salt and equimolar salt solution under static and dynamic conditions. Furthermore, the adsorption capacity of clinoptilolite was investigated when embedded in the MMM and in clay form. Two conditioning methods were compared: HCl and NaCl. Conditioned clinoptilolite with NaCl gave higher static adsorption capacities than with HCl which alters the chemical structure of clinoptilolite. The adsorption of Na+ was not detected in the static adsorption experiments and results showed that Na+ adsorbed during the conditioning process it was exchanged by K+ and NH4+. The clinoptilolite embedded in MMM reduced the porosity of the MMM so the highest adsorption capacity was reached when the amount of polymer was the lowest: 30 wt% polymer and 70 wt% clinoptilolite. The application of MMM in a dead-end filtration cell (dynamic adsorption) resulted in higher adsorption capacities compared to static conditions and comparable results between synthetic solutions and diluted urine samples. This indicates that MMM is a suitable method for the recovery of K+ and NH4+ directly from a diluted urine matrix. The desorption (recovery) of K+ and NH4+ from MMM was higher using water at 60 degrees C than using an acidic treatment. (C) 2015 Elsevier Ltd. All rights reserved

Koordinierte Einzelfoerderung zur Verfahrensentwicklung fuer texturierte HTSL-Massivmaterialien: Chemisch-physikalische Grundlagen zur HTSL-Material- und Verfahrensentwicklung Abschlussbericht

The goal of the work is to contribute to better understanding of melt processing of bulk HTSC materials and to support the development of improved bulk materials for cryomagnetic applications. The phase equilibria in the quarternary system Y-Ba-Cu-O have been investigated in terms of composition, T and p(O_2). Relations which are directly connected with technological aspects are outlined in more detail. A modified melt texturing process was proposed which includes thermodynamically controlled solidification. Combining this with a seeding method, single domain YBaCuO monoliths of 25 mm diameter with high levitation forces up to 50 N (with a 25 mm 0.42 T SmCo magnet) and trapped fields up to 0.55 T at 77 K have been achieved. Critical currents of 30 kA/cm"2 in YBaCuO and 40 kA/cm"2 in NdBaCuO have been measured. A field of 3.5 T was trapped in the 1 mm gap of 20 mm minimagnet at 30 K. Materials of this quality are necessary for levitation applications and excitation in electric machines. (orig.)Aufgabe des Vorhabens war, zum besseren Verstaendnis der Schmelztexturierung und Kristallisation von massiven Hochtemperatursupraleitern beizutragen und dadurch die Entwicklung von Materialien fuer kryomagnetische Anwendungen zu unterstuetzen. Es wurden Phasengleichgewichte im System YBaCuO bei unterschiedlichen Sauerstoffparialdruecken aufgeklaert, Zusammenhaenge mit unmittelbaren technologischen Auswirkungen wurden herausgestellt. Auf dieser Grundlage wurde ein modifizierter Schmelztexturierungsprozess vorgeschlagen. In Kombination mit einer Keimvorgabe konnten eindomaenige YBaCuO Monolithe von 25 mm Durchmesser entwickelt werden. Diese zeigen hohe Levitationskraefte von 50 N (gegen einen 0,42 T SmCo Magnet, d_2=25 mm) and hohe eingefrorene Felder bis 0,55 T bei 77 K. Kritische Stroeme bis 30 kA/cm"2 werden in YBaCuO und bis 40 kA/cm"2 in NdBaCuO erreicht. Zwischen 2 Monolithen wurde ein Feld von 3,5 T bei 30 K eingefroren. Materialien dieser Qualitaet erfuellen Anforderungen fuer moegliche Levitationsanwendungen und fuer Anwendungen in elektrischen Maschinen. (orig.)Available from TIB Hannover: F97B1436+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

The amyloid percursor protein of Alzheimer disease is expressed as a 130 kDa polypeptide in various cultured cell types.

none10The vascular and parenchymal amyloid deposits in Alzheimer disease (AD), normal aging and Down syndrome are mainly composed of a 4 kDa polypeptide (A4), which derives from a larger precursor protein (APP). There is evidence that APP is a transmembrane glycoprotein present in most tissues, but the characteristics of APP in intact cells are not yet known. In order to investigate this issue, we examined the immunoreactivity of fibroblasts of human and nonhuman cell lines with antisera raised to synthetic peptides corresponding to A4 and to two other domains of the APP. All three antisera recognized a 130 kDa polypeptide (APP-130) in immunoblots from all cell lines. In fibroblasts, an additional polypeptide of 228 kDa (APP-228) was recognized by the antiserum to A4. In immunoblots of two dimensional gels, APP-130 showed a pI of 6.2, while APP-228 failed to focus in the pH range of 4.7-7.0. Sequential extractions of cells with buffer and with Triton X-100 indicate that APP-130 is extractable with nonionic detergents at high ionic strength, whereas 228 kDa APP is a cystolic component. Immunofluorescence staining is consistent with an intracellular perinuclear and plasma membrane localization. It is concluded that APP-130 and APP-228 are two forms of the APP which result from extensive posttranslational modifications of a smaller original gene product. It is likely that APP undergoes similar posttranslational modifications in different cell types.L. Autilio-Gambetti;A. Morandi;M. Tabaton;B. Schaetzle;D. Kovacs;G. Perry;S. Sharma;J. Cornette;B. Greenberg;P. GambettiL., Autilio Gambetti; A., Morandi; Tabaton, Massimo; B., Schaetzle; D., Kovacs; G., Perry; S., Sharma; J., Cornette; B., Greenberg; P., Gambett

Texturierte HTSL-Massivmaterialien - Synthese und Charakterisierung. Chemisch-physikalische Grundlagen und Entwicklung texturierter HTSL-Materialien Abschlussbericht

Phase equilibria investigation have been performed in Y-Ba-Cu-O and Nd-Ba-Cu-O the results of which are the fundamentals of modified melt processing of these materials. Critical currents of 45 or 75 kA/cm"3 at H=0 T have been obtained in YBCO and NdBaCuO materials, respectively. The latter have been processed by an 'Oxygen pressure controlled isothermal process' (OCIP). An irreversibility field of 8.5 T (77 K) was measured in NdBaCuO whereas high levitation forces up to 87 N (77 K) have been achieved by YBaCuO combined with a 25 mm (0.4 T) SmCo magnet, and the specific levitation force was found to be 170 times the weight of the YBCO block or 18 N/cm"2 related to the top face area of the SmCo magnet, respectively. Trapped magnetic fields as high as 9.6 T have been achieved at 47 K in the gap of a minimagnet formed by two as grown YBCO cylinders with 1 inch diameter each. Fields up to 0.8 T (77 K) hve been measured along the top face of the single cylinders. Large plates of biaxially oriented subgrains have been grown by a multi-seeded process which are being tested for applications in the rotor of a 12 kW superconducting reluctance motor. (orig.)SIGLEAvailable from TIB Hannover: F99B760 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Natural history of periodontitis: Disease progression and tooth loss over 40years

ObjectivesTo assess long-term attachment and periodontitis-related tooth loss (PTL) in untreated periodontal disease over 40years