Examination of the coatings of coronary stents

In our study the main properties of coated coronary stents are shown, such as foreshortening, recoil, surface features and failures and the expansion properties. The types and the effects of active and passive coatings are introduced. The results of our examinations with different coated coronary stents are shown as well

Laser Cutting of Stainless Steel Thin Sheets with Pulsed Nd:Yag Laser

The parameters of laser cutting mainly depend on material and from thickness. In case of a given material and thickness many settings can be chosen. In this article we examine the laser cutting of 0,4 mm thickness stainless steel sheets with pulsed Nd:YAG laser. We examine the effect of cutting speed on cut quality in case of three different combinations of pulse energy and pulse frequency. Good cut quality and relatively high cutting speed can be achieved with 800 Hz and 20.7 mJ setting, we can cut higher speed, but poor cut quality with 400 Hz and 49 mJ setting

Internal Marketing Orientation in Cultural Change Management for Organisation Development

Non-Profit-Organizations of the Third Sector have lately gained an increasing importance both in scientific research and as far as their economical weight is concerned. Adapting the concept of the Balanced Scorecard for those organizations, their particularities need to be determined and based on the findings, the need of changes within and additions to the concept need to be questioned and discussed.Non-Profit-Organisationen, Balanced Scorecard, Controlling, Performance, Measurement

Laser beam cutting and welding of coronary stents

Coronary stents are thin-walled and mesh-structured metallic implants, which are made generally by laser beam cutting of high-precision tubes of 90-120 micrometer thickness. The tube material can be 316L stainless steel or L605 type cobalt-chromium alloy. The paper present how laser settings influence geometry and surface quality of the kerf and residual stresses, which play very important role in the precision of stent strut homogeneity. Hungarian Tentaur stent was developed 15 years ago. This coil stent made of 145 micrometers thick stainless steel wire contains 9-25 joints produced by electric resistance projection welding. Developments were bringing out for increasing flexibility of Tentaur stent, and a new design and a new tech-nology was elaborated, which’s based on laser beam mi-crowelding. TentaFlex stent also is constructed from austenitic stainless steel wire, but it does not contain any wire-crossing joint, because stent struts are configured from sinusoidal helix. Stent contains only two welded joints at its ends. Laser welding experiences of these joints are presented in the paper. A Trumpf PowerWeld Nd:YAG laser work station was used for welding, and after optimization of laser settings joints can’t produces from only one side of the coiled stent

AccPbFRET: An ImageJ plugin for semi-automatic, fully corrected analysis of acceptor photobleaching FRET images

<p>Abstract</p> <p>Background</p> <p>The acceptor photobleaching fluorescence resonance energy transfer (FRET) method is widely used for monitoring molecular interactions in cells. This method of FRET, while among those with the simplest mathematics, is robust, self-controlled and independent of fluorophore amounts and ratios.</p> <p>Results</p> <p>AccPbFRET is a user-friendly, efficient ImageJ plugin which allows fully corrected, pixel-wise calculation and detailed, ROI (region of interest)-based analysis of FRET efficiencies in microscopic images. Furthermore, automatic registration and semi-automatic analysis of large image sets is provided, which are not available in any existing FRET evaluation software.</p> <p>Conclusion</p> <p>Despite of the widespread applicability of the acceptor photobleaching FRET technique, this is the first paper where all possible sources of major errors of the measurement and analysis are considered, and AccPbFRET is the only program which provides the complete suite of corrections – for registering image pairs, for unwanted photobleaching of the donor, for cross-talk of the acceptor and/or its photoproduct to the donor channel and for partial photobleaching of the acceptor. The program efficiently speeds up the analysis of large image sets even for novice users and is freely available.</p

Different properties of coronary stents

Stents are mesh structured implants which are used to support the vessel wall in the balloon expanded vessel part. Several methods were developed and applied for the determination of mechanical properties of coronary stents, as a part of a complex pre-clinical in vitro diagnostic system: radiopacity, flaring, metallic surface area and fatigue tests. Three pieces of equipment were assembled for the examination of fatigue properties. The first method simulates the bending stress in the coronary arteries; the second method simulates the effect of the cylindrical mechanical strain which is equivalent to the systolic and diastolic pulse in the coronary arteries; and the third method is using the energy of the ultrasound concentrating to the stent. After fatigue tests stereomicroscopy, optical microscopy, scanning electron microscopy were used for the determination of surface quality and condition. The most frequent failures were scratches, pits and small shrinkage of materials originated from the manufacturing and finishing processes. Because of fatigue tests slip lines occurred in the critical curves, grain boundaries were outlined, the surface of the struts become rough, but these mutations do not affect the functionality of the stents

Development and Examination of Coated Coronary Stents

The aim of this study is to show the developments carried out by us with coated stents, expansion properties, furthermore the failures of the coatings. The coating was examined before and after expansion, paying special attention to the curves. The quality and the changing of the coatings were examined by different methods: optical microscopy, atomic force microscopy, scanning electron microscopy and EDS analysis. The results show that the expansion to a higher pressure did not change the coating. Polyurethane coating was given to TentAur stents. The coatings were produced by a method of dipping. The sterile and dust free environment is crucial to produce a suitable coating. Electro-polished and non-electro-polished sheets and stents were used for these experiments. The quality and the changing of the coatings were examined by different methods after drying. The fatigue tests showed that the polyurethane coating had suitable adherence