458 research outputs found
Unterschiede im Blutungsverhalten nach Ă–sophagusvarizenligatur
Background: Endoscopic band ligation (EBL) is generally accepted as the treatment of choice for bleeding from
esophageal varices. It is also used for secondary prophylaxis of esophageal variceal hemorrhage. However, there is
no data or guidelines concerning endoscopic control of ligation ulcers. We conducted a retrospective study of EBL
procedures analyzing bleeding complications after EBL.
Methods: We retrospectively analyzed data from patients who underwent EBL. We analyzed several data points,
including indication for the procedure, bleeding events and the time interval between EBL and bleeding.
Results: 255 patients and 387 ligation sessions were included in the analysis. We observed an overall bleeding rate
after EBL of 7.8%. Bleeding events after elective treatment (3.9%) were significantly lower than those after
treatment for acute variceal hemorrhage (12.1%). The number of bleeding events from ligation ulcers and variceal
rebleeding was 14 and 15, respectively. The bleeding rate from the ligation site in the group who underwent
emergency ligation was 7.1% and 0.5% in the group who underwent elective ligation. Incidence of variceal
rebleeding did not vary significantly. Seventy-five percent of all bleeding episodes after elective treatment occurred
within four days after EBL. 20/22 of bleeding events after emergency ligation occured within 11 days after
treatment. Elective EBL has a lower risk of bleeding from treatment-induced ulceration than emergency ligation.
Conclusions: Patients who underwent EBL for treatment of acute variceal bleeding should be kept under medical
surveillance for 11 days. After elective EBL, it may be reasonable to restrict the period of surveillance to four days
or even perform the procedure in an out-patient setting
Writing a Model Checker in 80 Days: Reusable Libraries and Custom Implementation
During a course on model checking we developed BMoth, a full-stack model checker for classical B, featuring both explicit-state and symbolic model checking. Given that we only had a single university term to finish the project, a particular focus was on reusing existing libraries to reduce implementation workload.In the following, we report on a selection of reusable libraries, which can be combined into a prototypical model checker relatively easily. Additionally, we discuss where custom code depending on the specification language to be checked is needed and where further optimization can take place. To conclude, we compare to other model checkers for classical B
Thermodynamic, Kinetic and Mechanical Modeling to Evaluate CO2-induced Corrosion via Oxidation and Carburization in Fe, Ni alloys
A computational framework integrating thermodynamics, kinetics, and
mechanical stress calculations is developed to study supercritical CO2 induced
corrosion in model Fe-based MA956 and Ni-based H214 alloys. Empirical models
parametrized using experimental data show surface oxidation and sub-surface
carburization for a wide range of thermodynamic conditions (800-1200 {\deg}C,
1-250 bar). CALPHAD simulations based on empirical models demonstrate higher
carburization resistance in H214 compared to MA956 below 900 {\deg}C and
through-thickness carburization in both alloys at higher temperatures. Finite
element modeling reveals enhanced volumetric misfit induced stresses at oxide
and carbide interfaces, and its critical dependence on the carbide chemistry
and concentration
Estimating and abstracting the 3D structure of feline bones using neural networks on X-ray (2D) images
Computing 3D bone models using traditional Computed Tomography (CT) requires a high-radiation dose, cost and time. We present a fully automated, domain-agnostic method for estimating the 3D structure of a bone from a pair of 2D X-ray images. Our triplet loss-trained neural network extracts a 128-dimensional embedding of the 2D X-ray images. A classifier then finds the most closely matching 3D bone shape from a predefined set of shapes. Our predictions have an average root mean square (RMS) distance of 1.08 mm between the predicted and true shapes, making our approach more accurate than the average achieved by eight other examined 3D bone reconstruction approaches. Each embedding extracted from a 2D bone image is optimized to uniquely identify the 3D bone CT from which the 2D image originated and can serve as a kind of fingerprint of each bone; possible applications include faster, image content-based bone database searches for forensic purposes
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