Nonmonotonic settling of a sphere in a cornstarch suspension\ud

Cornstarch suspensions exhibit remarkable behavior. Here, we present two unexpected observations for a sphere settling in such a suspension: In the bulk of the liquid the velocity of the sphere oscillates around a terminal value, without damping. Near the bottom the sphere comes to a full stop, but then accelerates again toward a second stop. This stop-go cycle is repeated several times before the object reaches the bottom. We show that common shear thickening or linear viscoelastic models cannot account for the observed phenomena, and propose a minimal jamming model to describe the behavior at the botto

Charakterisierung rekombinanter IgA-Antikörper gegen den EGFR

In der Therapie von epithelialen Karzinomen spielt die Behandlung mit Antigen-spezifischen Antikörpern eine große Rolle. Bei der Entwicklung von therapeutischen Antikörpern erwies sich der Rezeptor des epidermalen Wachstumsfaktors (EGFR) als geeignete Zielstruktur. Endogen exprimiert erfüllt er wichtige physiologische Funktionen bei der Entwicklung und Aufrechterhaltung der Epithelien. Die Überexpression des EGFR führt zu einem konstitutiven Anschalten von karzinomfördernden Signalwegen. Zwar sind die bisher klinisch erprobten Antikörper vom IgG-Isotyp, jedoch verfügen Antikörper vom IgA-Isotyp über interessante Eigenschaften. Im Gegensatz zu IgG- rekrutieren IgA-Antikörper keine NK-Zellen und aktivieren Monozyten und besonders effektiv Granulozyten. Diese stellen zwei für die Bekämpfung von soliden Tumoren wichtige und prozentual größere Effektorzellpopulationen dar. Zusätzlich ließe sich das Potential dieser Zellen durch Zugabe von Cytokinen (GM-CSF, G-CSF) weiter steigern. Im Unterschied zu IgG- diffundieren IgA-Antikörper in ihrer dimeren Form schneller durch Basalmembranen und werden durch Transzytose auf Epithelien transportiert. Im Rahmen dieser Arbeit konnten neue Verfahren für die Produktion und Aufreinigung von rekombinanten EGFR-gerichteten IgA-Antikörpern etabliert werden. Somit wird es nun möglich, ausreichende Mengen für klinische Anwendungen herzustellen. An den C-Terminus der J-Kette wurde eine Penta-Histidin-Markierung fusioniert. Dadurch war es möglich dimeres IgA spezifisch aufzureinigen und die Inkorporation der J-Kette nachzuverfolgen. Die weitere biochemische Charakterisierung ergab, dass die aufgereinigten Konstrukte aus korrekt zusammengebauten hochreinen monomerem und dimerem IgA bestanden. Die Charakterisierung der funktionellen Eigenschaften zeigte, dass die hergestellten IgA-Antikörper vergleichbar zu Kontrollantikörpern an EGFR und FcαRI banden sowie die Ligandenbindung blockierten, das Tumorzellwachstum inhibierten und antikörper-abhängige zelluläre Zytotoxicität (ADCC) vermittelten. Zum ersten Mal konnte gezeigt werden, dass hochreines definiertes monomeres und insbesondere dimeres IgA in der Lage waren Granulozyten und Monozyten zu rekrutieren. Dabei war der IgA2-Isotyp am effektivsten im Induzieren von ADCC. Dimeres IgA war in seiner direkten und indirekten Wirkung auf Tumorzellen effektiver als monomeres IgA. Darüber hinaus konnte gezeigt werden, dass dimeres IgA durch die Bindung an den pIgR mittels Transzytose eine Epithelzellschicht durchquerte. Darüber hinaus konnte für alle IgA-Antikörper gezeigt werden, dass sie nicht das Komplementsystem für die Lyse von Tumorzellen induzieren konnten. Im Rahmen dieser Arbeit konnten somit wichtige Voraussetzungen für nachfolgende (in vivo-) Experimente geschaffen werden

Surface bubble nucleation phase space

Recent research has revealed several different techniques for nanoscopic gas nucleation on submerged surfaces, with findings seemingly in contradiction with each other. In response to this, we have systematically investigated the occurrence of surface nanobubbles on a hydrophobised silicon substrate for various different liquid temperatures and gas concentrations, which we controlled independently. We found that nanobubbles occupy a distinct region of this phase space, occurring for gas concentrations of approximately 100-110%. Below the nanobubble phase we did not detect any gaseous formations on the substrate, whereas micropancakes (micron wide, nanometer high gaseous domains) were found at higher temperatures and gas concentrations. We moreover find that supersaturation of dissolved gases is not a requirement for nucleation of bubbles.Comment: 4 pages, 4 figure

Orthotopic Liver Transplantation: Is There a Risk for Listeria monocytogenes Infection?

Immunosuppression of any kind is a known risk factor for infection with Listeria monocytogenes (L. monocytogenes). Particularly, patients with impaired liver function are at increased risk of developing an aggravated course of infection with this bacterial pathogen (see Nolla-Salas et al.; 2002 and Cabellos et al.; 2008). It is a well-known pathogen in immunocompromised patients, but has only seldom been reported following orthotopic liver transplantation. Invasion of the central nervous system presenting as meningitis or meningoencephalitis and bacteremia are the principal clinical manifestations of listerial infections (see Brouwer et al.; 2006). We present an account of a case of a patient who developed L. monocytogenes meningitis during the early period after liver transplantation

Full-field strain determination for additively manufactured parts using radial basis functions

Additively manufactured components, especially those produced in deposition welding processes, have a rough curvilinear surface. Strain and surface deformation analysis of such components is increasingly performed using digital image correlation (DIC) methods, which raises questions regarding interpretability of the results. Furthermore, in triangulation or local tangential plane based DIC strain analysis, the principal strain directions are difficult to be calculated at any point, which is due to the non-continuity of the approach. Thus, both questions will be addressed in this article. Apart from classical local strain analysis based on triangulation or local linearization concepts, the application of globally formulated radial basis functions (RBF) is investigated for the first time, with the advantage that it is possible to evaluate all interesting quantities at arbitrary points. This is performed for both interpolation and regression. Both approaches are studied at three-dimensional, curvilinear verification examples and real additively manufactured cylindrical specimens. It is found out that, if real applications are investigated, the RBF-approach based on interpolation and regression has to be considered carefully due to so-called boundary effects. This can be circumvented by only considering the region that has a certain distance to the edges of the evaluation domain. Independent of the evaluation scheme, the error of the maximum principal strains increases with increasing surface roughness, which has to be kept in mind for such applications when interpreting or evaluating the results of manufactured parts. However, the entire scheme offers interesting properties for the treatment of DIC-data

Augmented Reality and Customer Experiences in Retail: A Case Study

This paper exposes the contingent implications of Augmented Reality (AR) on customer experiences in retail. We investigate how an AR application commissioned by the Danish designer house Louis Poulsen affects the customer experience in retail. Our study shows that AR provides possibilities to engineer the conditions influencing the customer experiences as well as to redistribute control of touchpoints in the customer journey. Consumer’s perception of the experience is exposed to a widening of the consumer-to-consumer influence, changing demographics, new event sequences and less manageable service recovery. Yet, these effects are contingent causalities where the effective harnessing of AR’s experience-enabling capacities require deep transformation of the existing structures by which customer experiences are formed. We therefore advance the argument that broad diffusion of AR in the retail setting will only happen in relation to a reformation of the retail industry, to which AR can contribute but not single-handedly motivate