Изучение адсорбции технеция-99м на оксиде алюминия из среды метилэтилкетона в статических и динамических условиях

Исследована адсорбция экстрагированного метилэтилкетоном 99mТс на гамма-оксиде алюминия с различной рН-формой в статических и динамических условиях проведения процесса. Определены коэффициенты распределения 99mТс в системе метилэтилкетон - 99mТс - оксид алюминия. Установлено, что максимальная сорбционная емкость по радионуклиду достигается на оксидах с рН-формой 4,5_6. В этих же условиях наблюдаются наименьшие потери 99mТс при проведении его адсорбции на хроматографической колонке и промывке колонки водой, а также наибольший выход 99mТс (более 95 %) при последующем его выделении в виде раствора натрия пертехнетата,99mТс. Показано, что общая продолжительность процесса отделения 99mТс от экстрагента не превышает 20 мин, что сопоставимо с временем получения элюата 99mТс из традиционных сорбционных генераторов, и, в конечном итоге, обеспечивает возможность создания ресурсоэффективных экологически чистых производств радиофармпрепаратов 99mТс

Combinatorial molecular optimization of cement hydrates

Despite its ubiquitous presence in the built environment, concrete’s molecular-level properties are only recently being explored using experimental and simulation studies. Increasing societal concerns about concrete’s environmental footprint have provided strong motivation to develop new concrete with greater specific stiffness or strength (for structures with less material). Herein, a combinatorial approach is described to optimize properties of cement hydrates. The method entails screening a computationally generated database of atomic structures of calcium-silicate-hydrate, the binding phase of concrete, against a set of three defect attributes: calcium-to-silicon ratio as compositional index and two correlation distances describing medium-range silicon-oxygen and calcium-oxygen environments. Although structural and mechanical properties correlate well with calcium-to-silicon ratio, the cross-correlation between all three defect attributes reveals an indentation modulus-to-hardness ratio extremum, analogous to identifying optimum network connectivity in glass rheology. We also comment on implications of the present findings for a novel route to optimize the nanoscale mechanical properties of cement hydrate.National Ready Mixed Concrete Association (Research sponsorship)Education Foundation (N.J.) (Research sponsorship)Portland Cement Association (Research sponsorship

Beiträge zur Geschichte des Landkreises Regensburg 24

24 Marginalien von 18 Autoren; darin: Werner, Hannsjürgen: Ein endneolithisches Körpergrab bei Moosham (S. 4); Fischer, T.: Die vor 110 Jahren erwähnt Burg Langenerling (S. 8); Bößl, Karl: Als Kareth zur freien Reichsstadt Regensburg gehörte (S. 10); Hummel, Franz: Der Hermann-, German- und Gerhof in der Gemeinde Wolfsegg (S. 12); Hemrich, Hans: Die letzte Ritterschlacht wurde bei Wenzenbach geschlagen (S. 14); Unterstöger, A.: Die Wallfahrtskirche St. Salvator in Donaustauf (S. 16); Daxl, Petra: Die Besiedlung der Hohengebrachinger Heide (S. 18); Neumann, Wenzel: Die Mötzinger Votivtafeln von 1775 und 1815 (S. 20); Schön, M.: Napoleon in Alteglofsheim (S. 22); Geser, Werner: Zum Alter der Wolfgangskapelle Klausen bei Thalmassing (S. 24); Jörgl, Fritz: Interessantes aus alten Geislinger Rechnungen (S. 25); Bösl, Hans-Josef: Die Heilung eines Taubstummen in der Wallfahrtskirche Mariae Schnee (S. 28); Fendl, Josef: Soll die Egglfinger Kirche verfallen? ( S. 30); Ebner, Karl: Aus der Geschichte des Schützenvereins Pfatter (S. 32); Staudigl, Franz Xaver: Beratzhausen in der Literatur (S. 34); Besenreiter, J.: Handwerk und Gewerbe in Aufhausen im Wandel der Zeit (S. 36); Forster, Fritz: Der Thurn- und Taxis´sche Wildpark (S. 38

On the driven Frenkel-Kontorova model: I. Uniform sliding states and dynamical domains of different particle densities

The dynamical behavior of a harmonic chain in a spatially periodic potential (Frenkel-Kontorova model, discrete sine-Gordon equation) under the influence of an external force and a velocity proportional damping is investigated. We do this at zero temperature for long chains in a regime where inertia and damping as well as the nearest-neighbor interaction and the potential are of the same order. There are two types of regular sliding states: Uniform sliding states, which are periodic solutions where all particles perform the same motion shifted in time, and nonuniform sliding states, which are quasi-periodic solutions where the system forms patterns of domains of different uniform sliding states. We discuss the properties of this kind of pattern formation and derive equations of motion for the slowly varying average particle density and velocity. To observe these dynamical domains we suggest experiments with a discrete ring of at least fifty Josephson junctions.Comment: Written in RevTeX, 9 figures in PostScrip

Genome wide profiling of human embryonic stem cells (hESCs), their derivatives and embryonal carcinoma cells to develop base profiles of U.S. Federal government approved hESC lines

BACKGROUND: In order to compare the gene expression profiles of human embryonic stem cell (hESC) lines and their differentiated progeny and to monitor feeder contaminations, we have examined gene expression in seven hESC lines and human fibroblast feeder cells using Illumina(® )bead arrays that contain probes for 24,131 transcript probes. RESULTS: A total of 48 different samples (including duplicates) grown in multiple laboratories under different conditions were analyzed and pairwise comparisons were performed in all groups. Hierarchical clustering showed that blinded duplicates were correctly identified as the closest related samples. hESC lines clustered together irrespective of the laboratory in which they were maintained. hESCs could be readily distinguished from embryoid bodies (EB) differentiated from them and the karyotypically abnormal hESC line BG01V. The embryonal carcinoma (EC) line NTera2 is a useful model for evaluating characteristics of hESCs. Expression of subsets of individual genes was validated by comparing with published databases, MPSS (Massively Parallel Signature Sequencing) libraries, and parallel analysis by microarray and RT-PCR. CONCLUSION: we show that Illumina's bead array platform is a reliable, reproducible and robust method for developing base global profiles of cells and identifying similarities and differences in large number of samples