Drug Distribution and Stent Retention of Drug Eluting Stents

In this paper the examinations of drug eluting coronary stents are shown, such as the morphology of the coatings before expansion, drug distribution, the methodology and the value of stent retention. Surface qualities of drug coatings were examined with stereo-microscope, metallographic microscope and scanning electron microscope. Examinations with confocal microscope show drug distribution in the coatings. Stent retention is a very important property of the stent system. Stent retention is a force, needed to the stent slip down from the balloon. Three drug eluting coronary stents were tested with our method

Mechanical Properties of Coronary Veins

There are several publications available and experiments were done regarding to the vessel biomechanical properties. In the range we could find in vitro and in vivo assessments data for elasticity properties. Even though we have many results in this topic we still don’t have enough data for special veins. Three coronary veins were investigated from pig’s heart. The aim of these experiments was to define and measure the longitudinal tensile stress and tensile strength of coronary veins. The tensile tests were done successfully and the tensile stress was defined in the range of 1.66-2.57 MPa

The biomechanical effect of root amputation and degree of furcation involvement on intracoronally splinted upper molar teeth – An in vitro study

Objectives: The aim of this study was to evaluate the effect of the amount of periodontal support and the presence or absence of root amputation on the fracture resistance of intracoronally splinted maxillary molar teeth.Materials and methods: 48 extracted human upper first molars and 48 s premolars were included in the study. All teeth underwent standard mesio-occluso-distal (MOD) (molars) and standard occluso-distal (OD) (premolars) cavity preparation. After the preparation, all molars were root canal treated, and 48 molar-premolar units were created by intracoronal splinting. The units were randomly divided into 4 groups (Groups A-D, 12 units per group): in Groups C and D, the disto-buccal (DB) roots of the molars were amputated, while in Groups A and B, no root amputation was performed. All units were embedded in methacrylate resin at different levels: in Groups A and C, at 4 mm apically from the cemento-enamel junction (CEJ), while in Groups B and D, at 6 mm apically from the CEJ, mimicking the different stages of furcation involvement. All units were submitted first to dynamic and then to static, load-to-fracture mechanical testing. Fracture resistance values were recorded fracture mode was analysed.Results: During the load-to-facture test, Groups A and B (without root amputation) were characterized by significantly higher fracture resistance values compared to Groups C and D (with root amputation) (p Conclusions: Root amputation has a negative effect on the fracture resistance of intracoronally splinted upper first molar-second premolar units with modeled furcation involvement.</p

Microscopic concavity and fluctuation bounds in a class of deposition processes

We prove fluctuation bounds for the particle current in totally asymmetric zero range processes in one dimension with nondecreasing, concave jump rates whose slope decays exponentially. Fluctuations in the characteristic directions have order of magnitude $t^{1/3}$. This is in agreement with the expectation that these systems lie in the same KPZ universality class as the asymmetric simple exclusion process. The result is via a robust argument formulated for a broad class of deposition-type processes. Besides this class of zero range processes, hypotheses of this argument have also been verified in the authors' earlier papers for the asymmetric simple exclusion and the constant rate zero range processes, and are currently under development for a bricklayers process with exponentially increasing jump rates.Comment: Improved after Referee's comments: we added explanations and changed some parts of the text. 50 pages, 1 figur

Stochastic integration based on simple, symmetric random walks

A new approach to stochastic integration is described, which is based on an a.s. pathwise approximation of the integrator by simple, symmetric random walks. Hopefully, this method is didactically more advantageous, more transparent, and technically less demanding than other existing ones. In a large part of the theory one has a.s. uniform convergence on compacts. In particular, it gives a.s. convergence for the stochastic integral of a finite variation function of the integrator, which is not c\`adl\`ag in general.Comment: 16 pages, some typos correcte

Prediction of the Shear Tension Strength of Resistance Spot Welded Thin Steel Sheets from High- to Ultrahigh Strength Range

The tensile strength of newly developed ultra-high strength steel grades is now above 1800 MPa, and even new steel grades are currently in development. One typical welding process to join thin steels sheets is resistance spot welding (RSW). Some standardized and not standardized formulas predict the minimal shear tension strength (STS) of RSWed joints, but those formulas are less and less accurate with the higher base materials strength. Therefore, in our current research, we investigated a significant amount of STS data of the professional literature and our own experiments and recommended a new formula to predict the STS of RSWed high strength steel joints. The proposed correlation gives a better prediction than the other formulas, not only in the ultra-high strength steel range but also in the lower steel strength domain