Computer-assisted ex vivo, normothermic small bowel perfusion

Background: In the present study, a technique for computer-assisted, normothermic, oxygenated, ex vivo, recirculating small bowel perfusion was established as a tool to investigate organ pretreatment protocols and ischemia/reperfusion phenomena. A prerequisite for the desired setup was an organ chamber for ex vivo perfusion and the use of syngeneic whole blood as perfusate. Methods: The entire small bowel was harvested from Lewis rats and perfused in an organ chamber ex vivo for at least 2 h. The temperature was kept at 37 degrees C in a water bath. Three experimental groups were explored, characterized by different perfusion solutions. The basic perfusate consisted of syngeneic whole blood diluted with either NaCl, Krebs' solution or Krebs' solution and norepinephrine to a hematocrit of 30%. In addition, in each group l-glutamine was administered intraluminally. The desired perfusion pressure was 100 mm Hg which was kept constant with a computer-assisted data acquisition software, which measured an-line pressure, oxygenation, flow, temperature and pH and adjusted the pressure by changing the flow via a peristaltic pump. The viability of the preparation was tested by measuring oxygen consumption and maltose absorption, which requires intact enzymes of the mucosal brush border to break down maltose into glucose. Results: Organ perfusion in group 1 (dilution with NaCl) revealed problems such as hypersecretion into the bowel lumen, low vascular resistance and no maltose uptake. In contrast a viable organ could be demonstrated using Krebs' solution as dilution solution. The addition of norepinephrine led to an improved perfusion over the entire perfusion period. Maltose absorption was comparable to tests conducted with native small bower. Oxygen consumption was stable during the 2-hour perfusion period. Conclusions: The ex vivo perfusion system established enables small bowel perfusion for at least 2 h. The viability of the graft could be demonstrated. The perfusion time achieved is sufficient to study leukocyte/lymphocyte interaction with the endothelium of the graft vessels. In addition, a viable small bowel, after 2 h of ex vivo perfusion, facilitates testing of pretreatment protocols for the reduction of the immunogenicity of small bowel allografts. Copyright (C) 2000 S. Karger AG, Basel

Mammals of Fort Leavenworth, Kansas: a 60-year followup to Brumwell (1951)

More than 60 years have elapsed since Brumwell\u27s (1951) comprehensive assessment during 193911940 of resident terrestrial vertebrates from Fort Leavenworth Military Rooervation in northeastern Kansas. Subsequent studies have been accomplished for the amphibians, reptiles, and birds. Our study is the first to assess intervening changes in the mammalian composition of this diverse local fauna. Notable observations include: the decline or extirpation of the black-tailed jackrabbit (Lepus californicus), Franklin\u27s ground squirrel (Spermophilus franklinii), muskrat (Ondatra zibethicus), long-tailed weasel (Mustela frenata) and eastern spotted skunk (Spilogale putorius); the return or recovery of locally extirpated gray fox (Urocyon cinereoargenteus), puma (Puma concolor), and white-tailed deer (Odocoileus virginianus), the increases of the once uncommon eastern chipmunk (Tamias striatus) and striped skunk (Mephitis mephitis), the invasion and establishment of the hispid cotton rat (Sigmodon hispidus), and the displacement of the eastern fox squirrel (Sciurus niger) by the eastern gray squirrel (S. carolinensis) as the most common squirrel. Documented species either not mentioned by Brumwell (1951) or listed by him as hypothetically occurring on the post, included northern myotis (Myotis septentrionalis), eastern pipistrelle (Pipistrellus subflavus), evening bat (Nycticeius humeralis), southern bog lemming (Synaptomys cooperi), and meadow jumping mouse (Zapus hudsonius)

Fluctuating magnetic moments in liquid metals

We re-analyze literature data on neutron scattering by liquid metals to show that non-magnetic liquid metals possess a magnetic moment that fluctuates on a picosecond time scale. This time scale follows the motion of the cage-diffusion process in which an ion rattles around in the cage formed by its neighbors. We find that these fluctuating magnetic moments are present in liquid Hg, Al, Ga and Pb, and possibly also in the alkali metals.Comment: 17 pages, 5 figures, submitted to PR

ifo Konjunkturprognose 2008: Konjunktur verliert an Fahrt

Am 13. Dezember 2007 stellte das ifo Institut im Rahmen seines vorweihnachtlichen Pressegesprächs seine Prognose für die Jahre 2008 und 2009 vor. Die Weltwirtschaft hat in diesem Jahr mit 5,2% erneut sehr kräftig expandiert. Allerdings sind die Risiken für die Konjunktur im Gefolge der Turbulenzen an den internationalen Finanzmärkten inzwischen merklich gestiegen. So hat sich das vom ifo Institut erhobene Weltwirtschaftsklima im 4. Quartal 2007 deutlich verschlechtert. Sowohl die Einschätzungen der derzeitigen wirtschaftlichen Lage als auch die Erwartungen für die nächsten sechs Monate wurden nach unten revidiert. Die Verschlechterung des ifo Wirtschaftsklimas betrifft alle drei großen Weltregionen, also Westeuropa, Nordamerika und Asien. Dabei ist der stärkste Rückgang des Klimaindikators in Nordamerika, und dort in erster Linie in den USA zu verzeichnen. Diese Datenkonstellation deutet daraufhin, dass sich das Tempo der Weltkonjunktur merklich verlangsamen wird. Die deutsche Konjunktur ist zum Jahresende 2007 weiter aufwärts gerichtet, wenn auch mit nachlassender Kraft. Die Dynamik hatte im vergangenen Winter einen Höhepunkt erreicht und lässt inzwischen wieder deutlich nach. Wie das ifo Institut im Dezember 2006 erwartet hatte, hat sich der seit 2005 laufende Aufschwung trotz der massiven Erhöhung der Mehrwertsteuer fortgesetzt. Die Auftriebskräfte aus dem In- und Ausland waren kräftig genug, um die restriktiven Wirkungen der Finanzpolitik zu verkraften. Konjunkturmotor war weiterhin die Auslandsnachfrage, die trotz der massiven Aufwertung des Euro gegenüber dem US-Dollar aufgrund der dynamischen Weltkonjunktur kräftig blieb. Im Jahresdurchschnitt 2007 expandierte das reale Bruttoinlandsprodukt um 2,5%. Allerdings gab es in diesem Jahr erneut eine etwas geringere Zahl von Arbeitstagen als 2006. Nach Ausschaltung dieser Kalenderschwankung ist die Zuwachsrate der Produktion auf 2,6% zu veranschlagen, was knapp unter dem Durchschnitt der alten EU-Länder liegt.Konjunktur, Konjunkturprognose, Konjunkturumfrage, Wirtschaftslage, Geschäftsklima, Weltkonjunktur, Deutschland, Welt

Growth Mechanism of Self-Catalyzed Group III−V Nanowires

Group III-V nanowires offer the exciting possibility of epitaxial growth on a wide variety of substrates, most importantly silicon. To ensure compatibility with Si technology, catalyst-free growth schemes are of particular relevance, to avoid impurities from the catalysts. While this type of growth is well-documented and some aspects are described, no detailed understanding of the nucleation and the growth mechanism has been developed. By combining a series of growth experiments using metal-organic vapor phase epitaxy, as well as detailed in situ surface imaging and spectroscopy, we gain deeper insight into nucleation and growth of self-seeded III-V nanowires. By this mechanism most work available in literature concerning this field can be described

Collective dynamics of liquid aluminum probed by Inelastic X-ray Scattering

An inelastic X-ray scattering experiment has been performed in liquid aluminum with the purpose of studying the collective excitations at wavevectors below the first sharp diffraction peak. The high instrumental resolution (up to 1.5 meV) allows an accurate investigation of the dynamical processes in this liquid metal on the basis of a generalized hydrodynamics framework. The outcoming results confirm the presence of a viscosity relaxation scenario ruled by a two timescale mechanism, as recently found in liquid lithium.Comment: 8 pages, 7 figure

Membrane Hsp70 — a novel target for the isolation of circulating tumor cells after epithelial-to-mesenchymal transition

The presence of circulating tumor cells (CTCs) in the peripheral blood is a pre-requisite for progression, invasion, and metastatic spread of cancer. Consequently, the enumeration and molecular characterization of CTCs from the peripheral blood of patients with solid tumors before, during and after treatment serves as a valuable tool for categorizing disease, evaluating prognosis and for predicting and monitoring therapeutic responsiveness. Many of the techniques for isolating CTCs are based on the expression of epithelial cell surface adhesion molecule (EpCAM, CD326) on tumor cells. However, the transition of adherent epithelial cells to migratory mesenchymal cells (epithelial-to-mesenchymal transition, EMT)—an essential element of the metastatic process—is frequently associated with a loss of expression of epithelial cell markers, including EpCAM. A highly relevant proportion of mesenchymal CTCs cannot therefore be isolated using techniques that are based on the “capture” of cells expressing EpCAM. Herein, we provide evidence that a monoclonal antibody (mAb) directed against a membrane-bound form of Hsp70 (mHsp70)—cmHsp70.1—can be used for the isolation of viable CTCs from peripheral blood of tumor patients of different entities in a more quantitative manner. In contrast to EpCAM, the expression of mHsp70 remains stably upregulated on migratory, mesenchymal CTCs, metastases and cells that have been triggered to undergo EMT. Therefore, we propose that approaches for isolating CTCs based on the capture of cells that express mHsp70 using the cmHsp70.1 mAb are superior to those based on EpCAM expression

Convergent Bayesian global fits of 4D composite Higgs models

Models in which the Higgs boson is a composite pseudo-Nambu-Goldstone boson offer attractive solutions to the Higgs mass naturalness problem. We consider three such models based on the minimal SO(5) → SO(4) symmetry breaking pattern, and perform convergent global fits on the models under a Bayesian framework in order to find the regions of their parameter spaces that best fit a wide range of constraints, including recent Higgs measurements. We use a novel technique to analyse the fine-tuning of the models, quantifying the tuning as the Kullback-Leibler divergence from the prior to the posterior probability on the parameter space. Each model is found to be able to satisfy all constraints at the 3σ level simultaneously. As a by-product of the fits, we analyse the collider phenomenology of our models in these viable regions. In two of the three models, we find that the gg → H → γγ cross section is less than ∼90% that predicted by the SM, which is already in slight tension with experiment and could potentially be ruled out in the future high-luminosity run of the LHC. In addition, the lightest fermions F arising from the new strong dynamics in these models are seen in general to lie above ∼1.1 TeV, with the F → tW+ and F → b¯¯W+ decays offering particularly promising channels for probing these models in future collider searches.Ethan Carragher, Will Handley, Daniel Murnane, Peter Stangl, Wei Su, Martin White, Anthony G. William

Evidence of short time dynamical correlations in simple liquids

We report a molecular dynamics (MD) study of the collective dynamics of a simple monatomic liquid -interacting through a two body potential that mimics that of lithium- across the liquid-glass transition. In the glassy phase we find evidences of a fast relaxation process similar to that recently found in Lennard-Jones glasses. The origin of this process is ascribed to the topological disorder, i.e. to the dephasing of the different momentum $Q$ Fourier components of the actual normal modes of vibration of the disordered structure. More important, we find that the fast relaxation persists in the liquid phase with almost no temperature dependence of its characteristic parameters (strength and relaxation time). We conclude, therefore, that in the liquid phase well above the melting point, at variance with the usual assumption of {\it un-correlated} binary collisions, the short time particles motion is strongly {\it correlated} and can be described via a normal mode expansion of the atomic dynamics.Comment: 7 pages, 7 .eps figs. To appear in Phys. Rev.