Drug‐Coated Angioplasty Balloon Catheters: Coating Compositions and Methods

Flow‐limiting stenosis or total occlusion of coronary, cerebral, or peripheral arteries is very common. Minimally invasive treatment with balloon catheters optionally combined with stent implantation immediately relieves symptoms. However, renarrowing of dilated vessel segments due to excessive scar formation frequently reverses the initial success observed soon after treatment. Coating of balloons with antiproliferative drugs is a promising approach to overcome this problem. The coating of angioplasty balloon membranes is a challenging task. It must ensure homogeneous distribution of the antiproliferative agent and adherence to the balloon membrane during handling and on the way to the treatment site in a distant artery, where the agent should be immediately released and transferred to the vessel wall when the balloon is inflated. In vitro and in vivo testing methods are described. The impact of different kinds of balloons, drugs, additives, and coating methods has been investigated, and the results of representative examples including clinically tested products are presented and discussed.     

A Multiperspective Approach to Solvent Regulation of Enzymatic Activity: HMG‐CoA Reductase

3‐Hydroxy‐3‐methylglutaryl–coenzyme A (HMG‐CoA) reductase was investigated in different organic cosolvents by means of kinetic and calorimetric measurements, molecular dynamics simulations, and small‐angle X‐ray scattering. The combined experimental and theoretical techniques were essential to complement each other's limitations in the investigation of the complex interaction pattern between the enzyme, different solvent types, and concentrations. In this way, the underlying mechanisms for the loss of enzyme activity in different water‐miscible solvents could be elucidated. These include direct inhibitory effects onto the active center and structural distortions.     

Private Computation: k-Connected versus 1-Connected Networks

We study the role of connectivity of communication networks in private computations under information theoretical settings in the honest-but-curious model. We show that some functions can be 1-privately computed even if the underlying network is 1-connected but not 2-connected. Then we give a complete characterisation of non-degenerate functions that can be 1-privately computed on non-2-connected networks. Furthermore, we present a technique for simulating 1-private protocols that work on arbitrary (complete) networks on k-connected networks. For this simulation, at most additional random bits are needed, where L is the number of bits exchanged in the original protocol and n is the number of players. Finally, we give matching lower and upper bounds for the number of random bits needed to compute the parity function on k-connected networks 1-privately, namely random bits for networks consisting of n players.     

Combined Region and Motion-Based 3D Tracking of Rigid and Articulated Objects

In this paper, we propose the combined use of complementary concepts for 3D tracking: region fitting on one side and dense optical flow as well as tracked SIFT features on the other. Both concepts are chosen such that they can compensate for the shortcomings of each other. While tracking by the object region can prevent the accumulation of errors, optical flow and SIFT can handle larger transformations. Whereas segmentation works best in case of homogeneous objects, optical flow computation and SIFT tracking rely on sufficiently structured objects. We show that a sensible combination yields a general tracking system that can be applied in a large variety of scenarios without the need to manually adjust weighting parameters.     

Interaction of Zoospores of the Green Alga Ulva with Bioinspired Micro‐ and Nanostructured Surfaces Prepared by Polyelectrolyte Layer‐by‐Layer Self‐Assembly

The interaction of spores of Ulva with bioinspired structured surfaces in the nanometer–micrometer size range is investigated using a series of coatings with systematically varying morphology and chemistry, which allows separation of the contributions of morphology and surface chemistry to settlement (attachment) and adhesion strength. Structured surfaces are prepared by layer‐by‐layer spray‐coating deposition of polyelectrolytes. By changing the pH during application of oppositely charged poly(acrylic acid) and polyethylenimine polyelectrolytes, the surface structures are systematically varied, which allows the influence of morphology on the biological response to be determined. In order to discriminate morphological from chemical effects, surfaces are chemically modified with poly(ethylene glycol) and tridecafluoroctyltriethoxysilane. This chemical modification changes the water contact angles while the influence of the morphology is retained. The lowest level of settlement is observed for structures of the order 2 µm. All surfaces are characterized with respect to their wettability, chemical composition, and morphological properties by contact angle measurement, X‐ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy.     

Influence of sulfated arabino- and glucuronoxylans charging-behavior regarding antithrombotic properties

During the last decade xylans were widely researched and several derivatives have been developed and analyzed. However, the application properties of these new products are still sparsely known. The main objective of the presented investigation was to examine whether sulfated xylans from different sources (hard wood and oat-spelt) possess antithrombotic properties and how their protonation/deprotonation behavior in water solutions influence these properties. Two types of xylans, glucuronoxylan derived from beech wood, and arabinoxylan from oat spelt, were sulfated. Infrared spectroscopy, elemental analysis, NMR and size exclusion chromatography were applied for analyzing the success of derivatization. Deprotonation/protonation behavior of xylan samples in water solutions was analyzed by titration methods and the antithrombotic properties were investigated using activated partial thromboplastin time determination.The results showed significant increases in negative charges for the sulfated samples, which were a consequence of introducing sulfated groups as strong acids. However, the increase of antithrombotic properties was not influenced only by the presence of certain amounts of sulfate functional groups but also by the total negative-charges originating from both sulfate and carboxyl groups. The later was proved by the high linear correlation between the activated partial thromboplastin time values, and the total charge of the samples.