85 research outputs found
Endoscopic submucosal dissection with a novel high viscosity injection solution (LiftUp) in an ex vivo model: a prospective randomized study
Introduction Endoscopic submucosal dissection (ESD) is increasingly being used in the western world. Submucosal injectates are an essential tool for the ESD procedure. In this study, we evaluated a novel copolymer injectate (LiftUp, Ovesco, Tübingen Germany) in an established ESD model (EASIE-R) in comparison to existing submucosal injectables. Materials and methods We conducted a prospective, randomized ex vivo study performing ESD with three injectates: LiftUp, hydroxyethyl starch (HAES 6 %) and normal saline solution (NaCl 0.9 %). A total of 60 artificial lesions, each 3 × 3 cm in size, were resected in an ex vivo porcine model, utilizing one of the three studied injectates (n = 20 ESDs per injectate). Study parameters were: en bloc resection rate, perforation rate, lifting property, time of injection, injectate volume, general ESD procedure time, and overall procedure time. Results All 60 lesions were successfully resected using the standard ESD technique. LiftUp had no procedure related perforations, one perforation occurred in the HAES group, and two perforations in the NaCl group ( P > 0.05). Furthermore, adequate lifting was achieved in 16/20 (80 %) using LiftUp, 6/20 (30 %) in the HAES group and 6/20 (30 %) in the NaCl group ( P < 0.0002). En bloc resection was achieved in 19 (95 %) with LiftUp, in 20 (100 %) with HAES, and in 16 (80 %) with NaCl. General ESD procedure time and overall procedure time were not different among the three groups. Conclusion LiftUp appears to be a safe alternative to established fluids for ESD. It had a significantly improved lifting effect and required significantly less injected volume compared to well-established lifting solutions
Cellular Automata Applications in Shortest Path Problem
Cellular Automata (CAs) are computational models that can capture the
essential features of systems in which global behavior emerges from the
collective effect of simple components, which interact locally. During the last
decades, CAs have been extensively used for mimicking several natural processes
and systems to find fine solutions in many complex hard to solve computer
science and engineering problems. Among them, the shortest path problem is one
of the most pronounced and highly studied problems that scientists have been
trying to tackle by using a plethora of methodologies and even unconventional
approaches. The proposed solutions are mainly justified by their ability to
provide a correct solution in a better time complexity than the renowned
Dijkstra's algorithm. Although there is a wide variety regarding the
algorithmic complexity of the algorithms suggested, spanning from simplistic
graph traversal algorithms to complex nature inspired and bio-mimicking
algorithms, in this chapter we focus on the successful application of CAs to
shortest path problem as found in various diverse disciplines like computer
science, swarm robotics, computer networks, decision science and biomimicking
of biological organisms' behaviour. In particular, an introduction on the first
CA-based algorithm tackling the shortest path problem is provided in detail.
After the short presentation of shortest path algorithms arriving from the
relaxization of the CAs principles, the application of the CA-based shortest
path definition on the coordinated motion of swarm robotics is also introduced.
Moreover, the CA based application of shortest path finding in computer
networks is presented in brief. Finally, a CA that models exactly the behavior
of a biological organism, namely the Physarum's behavior, finding the
minimum-length path between two points in a labyrinth is given.Comment: To appear in the book: Adamatzky, A (Ed.) Shortest path solvers. From
software to wetware. Springer, 201
Laser Lithotripsy — The New Wave
Currently more than 90% of all common bile duct concrements
can he removed via the endoscopic retrograde route by means of endoscopic
papillotomy, stone extraction by baskets and balloon catheters, or mechanical
lithotripsy. Oversized, very hard or impacted stones however often st ill resist
conventional endoscopic therapy. Laser lithotripsy represents a promising new
endoscopic approach to the nonsurgical treatment of those common bile duct
stones. Currently only short-pulsed laser systems with high power peaks but low
potential for thermal tissue damage are used for stone fragmentation. Systems in
clinical applications are the pulsed free-running-mode neodymium YAG
(Nd:YAG) laser (1064 nm, 2 ms) and the dye laser (504 nm, 1 to 1.5 μs). Energy
transmission via highly flexible 200 ìm quartz fibres allows an endoscopic
retrograde approach to the stone via conventional duodenoscope or mother-baby-scope systems. New systems currently in preclinical and first clinical testing
are the Q-switched Nd:YAG laser (1064 nm, 20 ns) and the Alexandrite laser
(700 to 815 nm, 30 to 500 ns). By means of extremely short nanosecond pulses
(10-9 s) for the induction of local shock waves at the stone surface, possible tissue
damage is even more reduced. No complications have been reported so far after
applying laser lithotripsy clinically in about 120 patients worldwide. Compared
to extracorporeal shock wave treatment, laser lithotripsy can be executed in any
endoscopy unit in the scope of the endoscopic pretreatment and does not require
general anesthesia, which is often necessary for extracorporeal shock wave
lithotripsy
JCASim - a Java system for simulating cellular automata
. The program system JCASim is a general-purpose system for simulating cellular automata in Java. It includes a stand-alone application and an applet for web presentations. The cellular automata can be specified in Java, in CDL, or using an interactive dialogue. The system supports many different lattice geometries (1-D, 2-D square, hexagonal, triangular, 3-D), neighborhoods, boundary conditions, and can display the cells using colors, text, or icons. We show several examples to demonstrate the wide applicability of the simulation system. 1 Introduction The concept of cellular automata is about fifty years old. In this period of time, a large number of people have written programs to simulate cellular automata (CA). Most of these programs were written to simulate one specific CA, but a significant number of simulation systems have been created for the simulation of "any" cellular automaton. An overview is given in [9]. Two systems we would like to single out developed around speciall..
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