Direct discrimination of cell surface glycosylation signatures using a single pH-responsive boronic acid-functionalized polymer

Cell surface glycans serve fundamental roles in many biological processes, including cell–cell interaction, pathogen infection, and cancer metastasis. Cancer cell surface have alternative glycosylation to healthy cells, making these changes useful hallmarks of cancer. However, the diversity of glycan structures makes glycosylation profiling very challenging, with glycan ‘fingerprints’ providing an important tool for assessing cell state. In this work, we utilized the pH-responsive differential binding of boronic acid (BA) moieties with cell surface glycans to generate a high-content six-channel BA-based sensor array that uses a single polymer to distinguish mammalian cell types. This sensing platform provided efficient discrimination of cancer cells and readily discriminated between Chinese hamster ovary (CHO) glycomutants, providing evidence that discrimination is glycan-driven. The BA-functionalized polymer sensor array is readily scalable, providing access to new diagnostic and therapeutic strategies for cell surface glycosylation-associated diseases.

A high-content multichannel sensor array was developed to efficiently discriminate cell states. The binding of boronic acid with glycans is pH-responsive, hence utilizing three pH provides a sensitive multidimensional array from a single polymer.     

Nitrogen‐doped zirconia single crystals

The aim of this work is the preparation of nitrogen‐doped single crystals of cation‐stabilized zirconia. Thin plates of these crystals were nitrided in a graphite heated resistance furnace with nitrogen as reaction gas. Several dwell times and reaction temperatures were tested and their effect on the amount of incorporated nitrogen is investigated. During nitridation at high temperatures a rock salt‐type ‘ZrN’ layer grows on the surface, leading to the destruction of the crystal. In contrast to the fluorite‐type bulk material, which can be described as a fast anion conductor, the surface layer shows electronic conductivity. For possible applications of the bulk material (solid electrolyte) the formation of the surface layer must be avoided. Therefore, the interface between surface epilayer and bulk material was investigated in detail by electron microscopy methods. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Bestimmung des Harnstoffs

Ohne Zusammenfassung     

Shape resonances in slow electron scattering by aromatic molecules. I. Anthraquinone derivatives

A series of anthraquinone (C(14)O(2)H(8)) derivatives has been studied by means of electron capture negative ion mass spectrometry (ECNI-MS), photoelectron spectroscopy (PES), and AM1 quantum chemical calculations. Mean lifetimes of molecular negative ions M(-.) (MNI) have been measured. The mechanism of long-lived MNI formation in the epithermal energy region of incident electrons has been investigated. A simple model of a molecule (a spherical potential well with the repulsive centrifugal term) has been applied for the analysis of the energy dependence of cross sections at the first stage of the electron capture process. It has been shown that a temporary resonance of MNI at the energy approximately 0.5 eV corresponds to a shape resonance with lifetime 1-2.10(-13) s in the f-partial wave (l = 3) of the incident electron. The next resonant state of MNI at the energy approximately 1.7 eV has been associated with the electron excited Feshbach resonance (whose parent state is a triplet npi* transition). In all cases the initial electron state of the MNI relaxes into the ground state by means of a radiationless transition, and the final state of the MNI is a nuclear excited resonance with a lifetime measurable on the mass spectrometry timescale. Copyright 1999 John Wiley & Sons, Ltd.     

Radar placement based on a geometric uncertainty multiplier reduction criterion

In this paper the problem of retrieving wind field information from Doppler radar data motivates the formulation of a method to design radar network configurations. The problem of estimating wind velocities from radar data is posed and used to construct a certain retrieval operator. This operator contains a factor that may be interpreted as an uncertainty multiplier. It depends on the geometry of the configuration of the radar network. The uncertainty multiplier is shown to vary continuously with perturbations of the network configuration. It is also shown to be a generalization of the Doppler angle condition used in meteorology. Numerical examples are presented to determine a network of five radars minimizing the uncertainty multiplier for the problem. Also, a configuration of sites is determined that maximizes the area of the Doppler region.     

Quantitative Infrarot-Messungen an Polyvinylchlorid-Weichmacher-Systemen

Zusammenfassung Methoden zur infrarotspektroskopischen Untersuchung von weichgemachten Polyvinylchlorid-(PVC-)Folien werden beschrieben. Die Ergebnisse von Intensitätsmessungen an Folien verschiedener PVC-Sorten und an Di-alkylphthalsäureestern werden mitgeteilt und diskutiert. Es wird gezeigt, daß in PVC-Phthalsäureester-Systemen Schlüsselfrequenzen (für PVC1430 cm^–1, für Phthalate 1728 cm. ^–1) vorhanden sind, die in einem technisch interessierenden Konzentrationsbereich dem Lambert-Beerschen Gesetz folgen und daher zur Konzentrationsbestimmung von Phthalsäureestern in PVC-Folien geeignet sind.Die für die Durchführung dieser Arbeit notwendigen apparativen Einrichtungen und die allgemeinen Sachmittel wurden uns von der Deutschen Forschungsgemeinschaft, dem Fonds der Chemie und vor allem von einem Arbeitskreis einiger deutscher Kabelwerke zur Verfügung gestellt. Wir danken den genannten Stellen für ihre wesentliche Hilfe.Auszugsweise vorgetragen von H. Loew     

Zur Messung der dielektrischen Verluste zur Bestimmung der Wechselwirkungen in Polyvinylchlorid-Weichmacher-Systemen

Zusammenfassung Am Beispiel des Systems Dioctylphthalat-Polyvinylchlorid wird gezeigt, da? der Verlauf der dielektrischen Verluste über der Temperatur nicht als Beweis für die Existenz „gebundenen“ und „freien“ Weichmachers in weichgemachtem Polyvinylchlorid gewertet werden kann. Die vorhandenen zwischenmolekularen Kr?fte zwischen den Komponenten k?nnen zwar zu Abweichungen einer idealen statistischen Verteilung der Systempartner, aber nicht zu einer Ausbildung st?chiometrisch zusammengesetzter Assoziate führen. Für die Mischungen gelten die Gesetze der Mischphasenthermodynamik (11).     

Enclosure of the Zero Set of Multivariate Exponential Interval Polynomials

The zero set of one general multivariate exponential polynomial with interval coefficients is enclosed by unions and intersections of closed half-spaces. Tighter enclosures are derived in the bivariate case. Common zeros of polynomial systems can be located by an appropriate intersection of these enclosure sets in an appropriate space. The resulting domains are directly brought into polynomial equation solvers.     

Plasma effects in picosecond-femtosecond UV laser ablation of polymers

Laser ablation of polyimide (PI) and polymethyl-methacrylate (PMMA) at 248 nm with pulse lengths ranging from 200 fs to 200 ps was investigated. The measured ablation rates show minima for pulse lengths of about 5 ps (PMMA) or 50 ps (PI).The reflected fraction of the ablating laser pulse was measured as a function of the pulse length. In the case of PMMA maximum reflectance corresponds to a minimum ablation rate.This behavior can be explained by a dynamic plasma reflection model: A fast build up of a dense plasma is followed by high obscuration for a brief transition time and a self-regulating opacity for the rest of the pulse. This model of plasma mediated ablation leads to a ^1/4-dependence of the ablation rate at fixed fluence, which fits very well to the measured data, in particular if an extension to nanosecond ablation data of PI and PMMA is considered. PACS 52.50.Jm; 61.80.Ba; 42.65.Re